In molecular biology, human chorionic gonadotropin (hCG) is a hormone produced by the syncytiotrophoblast, a portion of the placenta following implantation. The presence of hCG is detected in pregnancy tests. Some cancerous tumors produce this hormone; therefore, elevated levels measured when the patient is not pregnant can lead to a cancer diagnosis. However, it is not known whether this production is a contributing cause or an effect of tumorigenesis. The pituitary analog of hCG, known as luteinizing hormone (LH), is produced in the pituitary gland of males and females of all ages. As of December 6, 2011, the United States FDA has prohibited the sale of "homeopathic" and over-the-counter hCG diet products and declared them fraudulent and illegal.

Structure

Human chorionic gonadotropin is a glycoprotein composed of 237 amino acids with a molecular mass of 25.7 kDa.

It is heterodimeric, with an ? (alpha) subunit identical to that of luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), and ? (beta) subunit that is unique to hCG.

• The ? (alpha) subunit is 92 amino acids long.
• The ?-subunit of hCG gonadotropin (beta-hCG) contains 145 amino acids, encoded by six highly homologous genes that are arranged in tandem and inverted pairs on chromosome 19q13.3 - CGB (1, 2, 3, 5, 7, 8)

The two subunits create a small hydrophobic core surrounded by a high surface area-to-volume ratio: 2.8 times that of a sphere. The vast majority of the outer amino acids are hydrophilic.

Function

Human chorionic gonadotropin interacts with the LHCG receptor of the ovary and promotes the maintenance of the corpus luteum during the beginning of pregnancy. This allows the corpus luteum to secrete the hormone progesterone during the first trimester. Progesterone enriches the uterus with a thick lining of blood vessels and capillaries so that it can sustain the growing fetus. Due to its highly negative charge, hCG may repel the immune cells of the mother, protecting the fetus during the first trimester. It has also been hypothesized that hCG may be a placental link for the development of local maternal immunotolerance. For example, hCG-treated endometrial cells induce an increase in T cell apoptosis (dissolution of T cells). These results suggest that hCG may be a link in the development of peritrophoblastic immune tolerance, and may facilitate the trophoblast invasion, which is known to expedite fetal development in the endometrium. It has also been suggested that hCG levels are linked to the severity of morning sickness or Hyperemesis gravidarum in pregnant women.

Because of its similarity to LH, hCG can also be used clinically to induce ovulation in the ovaries as well as testosterone production in the testes. As the most abundant biological source is women who are presently pregnant, some organizations collect urine from pregnant women to extract hCG for use in fertility treatment.

Human chorionic gonadotropin also plays a role in cellular differentiation/proliferation and may activate apoptosis.

Production

Naturally, it is produced in the human placenta by the syncytiotrophoblast.

Like other gonadotropins, it can be extracted from the urine of pregnant women or produced from cultures of genetically modified cells using recombinant DNA technology.

In Pregnyl, Follutein, Profasi, Choragon and Novarel, it is extracted from the urine of pregnant women. In Ovidrel, it is produced with recombinant DNA technology.

hCG forms

Total hCG, C-terminal peptide total hCG, intact hCG, free ?-subunit hCG, ?-core fragment hCG, hyperglycosylated hCG, nicked hCG, alpha hCG, pituitary hCG.

Testing

Blood or urine tests measure hCG. These can be pregnancy tests. hCG-positive indicates an implanted blastocyst and mammalian embryogenesis. These can be done to diagnose and monitor germ cell tumors and gestational trophoblastic diseases.

Concentrations are commonly reported in thousandth international units per milliliter (mIU/ml). The international unit of hCG was originally established in 1938 and has been redefined in 1964 and in 1980. At the present time, 1 international unit is equal to approximately 2.35×10^-12 moles, or about 6×10^-8 grams.

Methodology

Most tests employ a monoclonal antibody, which is specific to the ?-subunit of hCG (?-hCG). This procedure is employed to ensure that tests do not make false positives by confusing hCG with LH and FSH. (The latter two are always present at varying levels in the body, whereas the presence of hCG almost always indicates pregnancy.)

Many hCG immunoassays are based on the sandwich principle, which uses antibodies to hCG labeled with an enzyme or a conventional or luminescent dye. Pregnancy urine dipstick tests are based on the lateral flow technique.

• The urine test may be a chromatographic immunoassay or any of several other test formats, home-, physician's office-, or laboratory-based. Published detection thresholds range from 20 to 100 mIU/ml, depending on the brand of test. Early in pregnancy, more accurate results may be obtained by using the first urine of the morning (when hCG levels are highest). When the urine is dilute (specific gravity less than 1.015), the hCG concentration may not be representative of the blood concentration, and the test may be falsely negative.

• The serum test, using 2-4 mL of venous blood, is typically a chemiluminescent or fluorimetric immunoassay that can detect ?hCG levels as low as 5 mIU/ml and allows quantification of the ?hCG concentration.

Reference levels in normal pregnancy

The following is a list of serum hCG levels. (LMP is the last menstrual period dated from the first day of your last period.) The levels grow exponentially after conception and implantation.

Interpretation

The ability to quantitate the ?hCG level is useful in the monitoring germ cell and trophoblastic tumors, follow-up care after miscarriage, and in diagnosis of and follow-up care after treatment of ectopic pregnancy. The lack of a visible fetus on vaginal ultrasound after the ?hCG levels have reached 1500 mIU/ml is strongly indicative of an ectopic pregnancy. Still, even an hCG over 2000 IU/l does not necessarily exclude the presence of a viable intrauterine pregnancy in such cases.

As pregnancy tests, quantitative blood tests and the most sensitive urine tests usually detect hCG between 6 and 12 days after ovulation. However, it must be taken into account that total hCG levels may vary in a very wide range within the first 4 weeks of gestation, leading to false results during this period. A rise of 35% over 48 hours is proposed as the minimal rise consistent with a viable intrauterine pregnancy.

Gestational trophoblastic disease like hydatidiform moles ("molar pregnancy") or choriocarcinoma may produce high levels of ?hCG (due to the presence of syncytialtrophoblasts- part of the villi that make up the placenta) despite the absence of an embryo. This, as well as several other conditions, can lead to elevated hCG readings in the absence of pregnancy.

hCG levels are also a component of the triple test, a screening test for certain fetal chromosomal abnormalities/birth defects.

A study of 32 normal pregnancies came to the result a gestational sac of 1-3 mm was detected at a mean hCG level of 1150 UI/l (range 800-1500), a yolk sac was detected at a mean level of 6000 UI/l (range 4500-7500) and fetal heartbeat was visible at a mean hCG level of 10,000 UI/l (range 8650-12,200).

Uses

Tumor marker

Human chorionic gonadotropin can be used as a tumor marker, as its ? subunit is secreted by some cancers including seminoma, choriocarcinoma, germ cell tumors, hydatidiform mole formation, teratoma with elements of choriocarcinoma, and islet cell tumor. For this reason a positive result in males can be a test for testicular cancer. The normal range for men is between 0-5 mIU/mL. Combined with alpha-fetoprotein, ?-HCG is an excellent tumor marker for the monitoring of germ cell tumors.

Fertility

Human chorionic gonadotropin is extensively used parenterally for final maturation induction in lieu of luteinizing hormone. In the presence of one or more mature ovarian follicles, ovulation can be triggered by the administration of HCG. As ovulation will happen between 38 and 40 hours after a single HCG injection, procedures can be scheduled to take advantage of this time sequence, such as intrauterine insemination or sexual intercourse. Also, patients that undergo IVF, in general, receive HCG to trigger the ovulation process, but have an oocyte retrieval performed at about 34 to 36 hours after injection by, a few hours before the eggs actually would be released from the ovary.

As HCG supports the corpus luteum, administration of HCG is used in certain circumstances to enhance the production of progesterone.

In the male, HCG injections are used to stimulate the Leydig cells to synthesize testosterone. The intratesticular testosterone is necessary for spermatogenesis from the sertoli cells. Typical uses for HCG in men include hypogonadism and fertility treatment.

During first few months of pregnancy, the transmission of HIV-1 from woman to fetus is extremely rare. It has been suggested that this is due to the high concentration of HCG, and that the beta-subunit of this protein is active against HIV-1.

HCG Pregnyl Warnings

In the case of female patients who want to be treated with HCG Pregnyl: a) Since infertile female patients who undergo medically assisted reproduction (especially those who need in vitro fertilization), are known to often be suffering from tubal abnormalities, after a treatment with this drug they might experience many more ectopic pregnancies. This is why early ultrasound confirmation at the beginning of a pregnancy (to see whether the pregnancy is intrauterine or not) is crucial. - Pregnancies that have occurred after a treatment with this medicine are submitted to a higher risk of multiplets. - Female patients who have thrombosis, severe obesity or thrombophilia should not be prescribed this medicine as they have a higher risk of arterial or venous thromboembolic events after or during a treatment with HCG Pregnyl. b)Female patients who have been treated with this medicine are usually more prone to pregnancy losses.

In the case of male patients: A prolonged treatment with HCG Pregnyl is known to regularly lead to increased production of androgen. Therefore: Patients who are suffering from overt or latent cardiac failure, hypertension, renal dysfunction, migraines or epilepsy might not be allowed to start using this medicine or may require a lower dose of HCG Pregnyl. Also this medicine should be used with extreme caution in the treatment of prepubescent teenagers in order to reduce the risk of precocious sexual development or premature epiphyseal closure. This type of patients' skeletal maturation should be closely and regularly monitored.

Both male and female patients who have the following medical conditions must not start a treatment with HCG Pregnyl: (1) Hypersensitivity to this medicine or to any of its main ingredients. (2) Known or possible androgen-dependent tumors for example male breast carcinoma or prostatic carcinoma.

Anabolic steroid adjunct

In the world of performance-enhancing drugs, HCG is increasingly used in combination with various anabolic androgenic steroid (AAS) cycles. As a result, HCG is included in some sports' illegal drug lists.

When exogenous AAS are put into the male body, natural negative-feedback loops cause the body to shut down its own production of testosterone via shutdown of the hypothalamic-pituitary-gonadal axis (HPGA). This causes testicular atrophy, among other things. HCG is commonly used during and after steroid cycles to maintain and restore testicular size as well as normal testosterone production.

High levels of AASs, that mimic the body's natural testosterone, trigger the hypothalamus to shut down its production of gonadotropin-releasing hormone (GnRH) from the hypothalamus. Without GnRH, the pituitary gland stops releasing luteinizing hormone (LH). LH normally travels from the pituitary via the blood stream to the testes, where it triggers the production and release of testosterone. Without LH, the testes shut down their production of testosterone. In males, HCG helps restore and maintain testosterone production in the testes by mimicking LH and triggering the production and release of testosterone.

If HCG is used for too long and in too high a dose, the resulting rise in natural testosterone would eventually inhibit its own production via negative feedback on the hypothalamus and pituitary gland.

Professional athletes who have tested positive for HCG have been temporarily banned from their sport, including a 50-game ban from MLB for Manny Ramirez in 2009 and a 4-game ban from the NFL for Brian Cushing for a positive urine test for HCG. Mixed Martial Arts fighter Dennis Siver was fined $19,800 and suspended 9 months for being tested positive after his bout at UFC 168.

HCG diet

British endocrinologist Albert T. W. Simeons proposed HCG as an adjunct to an ultra-low-calorie weight-loss diet (less than 500 calories). Simeons, while studying pregnant women in India on a calorie-deficient diet, and "fat boys" with pituitary problems (Frölich's syndrome) treated with low-dose HCG, observed that both lost fat rather than lean (muscle) tissue. He reasoned that HCG must be programming the hypothalamus to do this in the former cases in order to protect the developing fetus by promoting mobilization and consumption of abnormal, excessive adipose deposits. Simeons in 1954 published a book entitled Pounds and Inches, designed to combat obesity. Simeons, practicing at Salvator Mundi International Hospital in Rome, Italy, recommended low-dose daily HCG injections (125 IU) in combination with a customized ultra-low-calorie (500 cal/day, high-protein, low-carbohydrate/fat) diet, which was supposed to result in a loss of adipose tissue without loss of lean tissue.

Simeons' results were not reproduced by other researchers and in 1976 in response to complaints the FDA required Simeons and others to include the following disclaimer on all advertisements:

There was a resurgence of interest in the "HCG diet" following promotion by Kevin Trudeau who was later banned from making HCG diet weight-loss claims by the U.S. Federal Trade Commission.

Review studies refuting the HCG diet have been published in the Journal of the American Medical Association and the American Journal of Clinical Nutrition, both concluding that HCG is neither safe nor effective as a weight-loss aid.

A meta analysis found that studies supporting HCG for weight loss were of poor methodological quality and concluded that "there is no scientific evidence that HCG is effective in the treatment of obesity; it does not bring about weight-loss or fat-redistribution, nor does it reduce hunger or induce a feeling of well-being".

According to the American Society of Bariatric Physicians, no new clinical trials have been published since the definitive 1995 meta-analysis.

The scientific consensus is that any weight loss reported by individuals on an "HCG diet" may be attributed entirely to the fact that such diets prescribe calorie intake of between 500 and 1,000 calories per day, substantially below recommended levels for an adult, to the point that this may risk health effects associated with malnutrition.

Homeopathic HCG for weight control

Controversy about, and shortages of, injected HCG for weight loss have led to substantial Internet promotion of "homeopathic HCG" for weight control. The ingredients in these products are often obscure, but if prepared from true HCG via homeopathic dilution, they contain either no HCG at all or only trace amounts. Moreover, it is highly unlikely that oral HCG is bioavailable due to the fact that digestive protease enzymes and hepatic metabolism renders peptide-based molecules (such as insulin and human growth hormone) biologically inert. HCG can likely only enter the bloodstream through injection.

The United States Food and Drug Administration has stated that over-the-counter products containing HCG are fraudulent and ineffective for weight loss. They are also not protected as homeopathic drugs and have been deemed illegal substances. HCG itself is classified as a prescription drug in the United States and it has not been approved for over-the-counter sales by the FDA as a weight loss product or for any other purposes, and therefore neither HCG in its pure form nor any preparations containing HCG may be sold legally in the country except by prescription. In December 2011, FDA and FTC started to take actions to pull unapproved HCG products from the market. In the aftermath, some suppliers started to switch to "hormone-free" versions of their weight loss products, where the hormone is replaced with an unproven mixture of free amino acids or where radionics is used to transfer the "energy" to the final product.

See also

• Equine chorionic gonadotropin
• Gonadotropin preparations
• Human placental lactogen
• Triple test - a screening test in pregnancy
• The Weight-Loss Cure "They" Don't Want You to Know About - Kevin Trudeau's book

References

External links

• Chorionic Gonadotropin at the US National Library of Medicine Medical Subject Headings (MeSH)
• History of pregnancy test (NIH)
• All you need to know about using HCG for weight loss

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Nerve compression syndrome or compression neuropathy, also known as entrapment neuropathy, is a medical condition caused by direct pressure on a single nerve. It is known colloquially as a trapped nerve, though this may also refer to nerve root compression (by a herniated disc, for example). Its symptoms include pain, tingling, numbness, and muscle weakness. The symptoms affect just one particular part of the body, depending on which nerve is affected. Nerve conduction studies help to confirm the diagnosis. In some cases, surgery may help to relieve the pressure on the nerve, but this does not always relieve all the symptoms.

Nerve injury by a single episode of physical trauma is in one sense a compression neuropathy, but is not usually included under this heading.

Pathophysiology

External pressure reduces flow in the vessels supplying the nerve with blood (the vasa nervorum). This causes local ischaemia, which has an immediate effect on the ability of the nerve axons to transmit action potentials. As the compression becomes more severe over time, focal demyelination occurs, followed by axonal damage, and finally scarring.

Causes

A nerve may be compressed by prolonged or repeated external force, such as sitting with one's arm over the back of a chair (radial nerve), frequently resting one's elbows on a table (ulnar nerve), or an ill-fitting cast or brace on the leg (peroneal nerve).

Part of the patient's own body can cause the compression, and the term entrapment neuropathy is used particularly in this situation. The offending structure may be a well-defined lesion such as a tumour (for example a lipoma, neurofibroma or metastasis), a ganglion cyst or a haematoma. Alternatively, there may be expansion of the tissues around a nerve in a space where there is little room for this to occur, as is often the case in carpal tunnel syndrome. This may be due to weight gain or peripheral oedema (especially in pregnancy), or to a specific condition such as acromegaly, hypothyroidism or scleroderma and psoriasis.

Some conditions cause nerves to be particularly susceptible to compression. These include diabetes, in which the blood supply to the nerves is already compromised, rendering the nerve more sensitive to minor degrees of compression. The genetic condition HNPP is a much rarer cause.

Diagnosis

The symptoms and signs depend on which nerve is affected, where along its length the nerve is affected, and how severely the nerve is affected. Positive sensory symptoms are usually the earliest to occur, particularly tingling and neuropathic pain, followed or accompanied by reduced sensation or complete numbness. Muscle weakness is usually noticed later, and is often associated with muscle atrophy.

A compression neuropathy can usually be diagnosed confidently on the basis of the symptoms and signs alone. However, nerve conduction studies are helpful in confirming the diagnosis, quantifying the severity, and ruling out involvement of other nerves (suggesting a mononeuritis multiplex or polyneuropathy). A scan is not usually necessary, but may be helpful if a tumour or other local compressive lesion is suspected.

Nerve injury, as a mononeuropathy, may cause similar symptoms to compression neuropathy. This may occasionally cause diagnostic confusion, particularly if the patient does not remember the injury and there are no obvious physical signs to suggest it.

The symptoms and signs of each particular syndrome are discussed on the relevant pages, listed below.

Treatment

When an underlying medical condition is causing the neuropathy, treatment should first be directed at this condition. For example, if weight gain is the underlying cause, then a weight loss program is the most appropriate treatment. Compression neuropathy occurring in pregnancy often resolves after delivery, so no specific treatment is usually required.

Some compression neuropathies are amenable to surgery: carpal tunnel syndrome and cubital tunnel syndrome are two common examples. Whether or not it is appropriate to offer surgery in any particular case depends on the severity of the symptoms, the risks of the proposed operation, and the prognosis if untreated. After surgery, the symptoms may resolve completely, but if the compression was sufficiently severe or prolonged then the nerve may not recover fully and some symptoms may persist.

Drug treatment may be useful for an underlying condition (including peripheral oedema), or for ameliorating neuropathic pain.

List of syndromes

Upper limb

Lower limb, abdomen and pelvis

See also

• Mononeuropathy
• Neuropathy
• Plexopathy
• Sciatica
• Spinal disc herniation
• Thoracic outlet syndrome

References

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Spirulina is a cyanobacterium that can be consumed by humans and other animals. There are two species, Arthrospira platensis and Arthrospira maxima.

Arthrospira is cultivated worldwide; used as a dietary supplement as well as a whole food; and is also available in tablet, flake and powder form. It is also used as a feed supplement in the aquaculture, aquarium and poultry industries.

Nutrient and vitamin content

Protein

Dried spirulina contains about 60% (51-71%) protein. It is a complete protein containing all essential amino acids, though with reduced amounts of methionine, cysteine and lysine when compared to the proteins of meat, eggs and milk. It is, however, superior to typical plant protein, such as that from legumes.

The U.S. National Library of Medicine said that spirulina was no better than milk or meat as a protein source, and was approximately 30 times more expensive per gram.

Other nutrients

Spirulina's lipid content is about 7% by weight, and is rich in gamma-linolenic acid (GLA), and also provides alpha-linolenic acid (ALA), linoleic acid (LA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA). Spirulina contains vitamins B₁ (thiamine), B₂ (riboflavin), B₃ (nicotinamide), B₆ (pyridoxine), B₉ (folic acid), vitamin C, vitamin A, and vitamin E. It is also a source of potassium, calcium, chromium, copper, iron, magnesium, manganese, phosphorus, selenium, sodium, and zinc. Spirulina contains many pigments which may be beneficial and bioavailable, including beta-carotene, zeaxanthin, 7-hydroxyretinoic acid, isomers, chlorophyll-a, xanthophyll, echinenone, myxoxanthophyll, canthaxanthin, diatoxanthin, 3'-hydroxyechinenone, beta-cryptoxanthin, and oscillaxanthin, plus the phycobiliproteins c-phycocyanin and allophycocyanin.

Vitamin B₁₂ controversy

Spirulina is not considered to be a reliable source of Vitamin B₁₂. Spirulina supplements contain predominantly pseudovitamin B₁₂, which is biologically inactive in humans. Companies which grow and market spirulina have claimed it to be a significant source of B₁₂ on the basis of alternative, unpublished assays, although their claims are not accepted by independent scientific organizations. The American Dietetic Association and Dietitians of Canada in their position paper on vegetarian diets state that spirulina cannot be counted on as a reliable source of active vitamin B₁₂. The medical literature similarly advises that spirulina is unsuitable as a source of B₁₂.

Risks

Toxicological studies

Toxicological studies of the effects of spirulina consumption on humans and animals, including feeding as much as 800 mg/kg, and replacing up to 60% of protein intake with spirulina, have shown no toxic effects. Fertility, teratogenicity, peri- and post-natal, and multi-generational studies on animals also have found no adverse effects from spirulina consumption.

Quality-related safety issues

Spirulina is a form of cyanobacterium, some of which are known to produce toxins such as microcystins, BMAA, and others. Some spirulina supplements have been found to be contaminated with microcystins, albeit at levels below the limit set by the Oregon Health Department. Microcystins can cause gastrointestinal disturbances and, in the long term, liver cancer. The effects of chronic exposure to even very low levels of microcystins are of concern, because of the potential risk of cancer.

These toxic compounds are not produced by spirulina itself, but may occur as a result of contamination of spirulina batches with other toxin-producing blue-green algae. Because spirulina is considered a dietary supplement in the U.S., there is no active, industry-wide regulation of its production and no enforced safety standards for its production or purity. The U.S. National Institutes of Health describes spirulina supplements as "possibly safe", provided they are free of microcystin contamination, but "likely unsafe" (especially for children) if contaminated. Given the lack of regulatory standards in the U.S., some public-health researchers have raised the concern that consumers cannot be certain that spirulina and other blue-green algae supplements are free of contamination.

Heavy-metal contamination of spirulina supplements has also raised concern. The Chinese State Food and Drug Administration reported that lead, mercury, and arsenic contamination was widespread in spirulina supplements marketed in China.

Safety issues for certain target groups

Due to very high Vitamin K content, patients undergoing anticoagulant treatments should not change consumption patterns of spirulina without seeking medical advice to adjust the level of medication accordingly.

Like all protein-rich foods, spirulina contains the essential amino acid phenylalanine (2.6-4.1 g/100 g), which should be avoided by people who have phenylketonuria, a rare genetic disorder that prevents the body from metabolizing phenylalanine, which then builds up in the brain, causing damage.

Etymology and ecology

The maxima and plaetensis species were once classified in the genus Spirulina. There is now agreement that they are in fact Arthrospira; nevertheless, and somewhat confusingly, the older term Spirulina remains in use for historical reasons.

Arthrospira are free-floating filamentous cyanobacteria characterized by cylindrical, multicellular trichomes in an open left-hand helix. They occur naturally in tropical and subtropical lakes with high pH and high concentrations of carbonate and bicarbonate. Arthrospira platensis occurs in Africa, Asia and South America, whereas Arthrospira maxima is confined to Central America. Most cultivated spirulina is produced in open channel raceway ponds, with paddle-wheels used to agitate the water. The largest commercial producers of spirulina are located in the United States, Thailand, India, Taiwan, China, Bangladesh, Pakistan, Burma (a.k.a. Myanmar), Greece, and Chile.

Spirulina thrives at a pH around 8.5 +, which will get more alkaline, and a temperature around 30 °C (86 °F). They are able to make their own food, and do not need a living energy or organic carbon source. In addition, spirulina have to have an ensemble of nutrients to thrive in a home aquarium or pond. A simple nutrient feed for growing Spirulina is:

• Baking soda- 16 g/L (61 g/US gal)
• Potassium nitrate- 2 g/L (7.6 g/US gal)
• Sea salt- 1 g/L (3.8 g/US gal)
• Potassium phosphate- 0.1 g/L (0.38 g/US gal)
• Iron sulphate- 0.0378 g/L (0.143 g/US gal)

which can all be found in aquarium or else in the agricultural division, all commonly occurring compounds except for the iron sulphate. The algae has actually been tested and successfully grown in human urine at 1:180 parts. After 7days, 97% of NH4+-N, 96.5% of total phosphorus (TP) and 85-98% of urea in the urine (ca. 120-diluted) were removed by the microalgae under autotrophic culture (30 °C).

Historical use

Spirulina was a food source for the Aztecs and other Mesoamericans until the 16th century; the harvest from Lake Texcoco and subsequent sale as cakes were described by one of Cortés' soldiers. The Aztecs called it "tecuitlatl".

Spirulina was found in abundance at Lake Texcoco by French researchers in the 1960s, but there is no reference to its use by the Aztecs as a daily food source after the 16th century, probably due to the draining of the surrounding lakes for agricultural and urban development. The first large-scale spirulina production plant, run by Sosa Texcoco, was established there in the early 1970s.

Spirulina has also been traditionally harvested in Chad. It is dried into cakes called dihé, which are used to make broths for meals, and also sold in markets. The spirulina is harvested from small lakes and ponds around Lake Chad.

Research

At present, research is preliminary. According to the U.S. National Institutes of Health, there is insufficient scientific evidence to recommend spirulina supplementation for any human condition, and more research is needed to clarify its benefits, if any.

Administration of spirulina has been investigated as a way to control glucose in people with diabetes, but the EFSA rejected those claims in 2013.

Advocates

In 1974, the World Health Organization described Spirulina as "an interesting food for multiple reasons, rich in iron and protein, and is able to be administered to children without any risk," considering it "a very suitable food." The United Nations established the Intergovernmental Institution for the use of Micro-algae Spirulina Against Malnutrition in 2003.

In the late 1980s and early 90s, both NASA (CELSS) and the European Space Agency (MELISSA) proposed Spirulina as one of the primary foods to be cultivated during long-term space missions.

See also

• Algaculture - commercial farming of algae
• Aphanizomenon flos-aquae

Notes and references

External links

• "Blue-green Algae". MedlinePlus. National Institutes of Health. December 2011. 
• "Blue-green Algae". Memorial Sloan-Kettering Cancer Center. December 2011. 
• "Spirulina". University of Maryland Medical Center. June 2011. 
• "Spirulina". Beth Israel Deaconess Medical Center. August 2011. 
• "Intergovernmental Institution for the use of Micro-algae Spirulina Against Malnutrition". 

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Body contouring is any procedure that alters the shape of different areas of the body. Body contouring after massive weight loss refers to a series of procedures that eliminate and/or reduce excess skin and fat that remains after previously obese individuals have lost a significant amount of weight, in a variety of places including the torso, upper arms, chest, and thighs.

History

Obesity is in epidemic proportions in the US and many parts of the world. It is defined as a condition where a person's body mass index (BMI) is 30 or greater. BMI is calculated by dividing the patient's weight in kilograms by their height in meters, squared. Normal weight individuals have a BMI that ranges from 18 to 25. Overweight people have a BMI from 26 to 30, with 30 and above people considered obese. Once the BMI reaches 35 and above, patients are considered morbidly obese. From a BMI of 30 and above a person's life span is shortened. In addition, obesity negatively affects the economic health of a society as well as other aspects of adult and child health, often for life. Childhood obesity is on the rise in Europe as well.

Bariatric surgery

In response to a serious obesity crisis, medical science has devised a handful of bariatric (obesity treatment) surgeries, including gastric bypass, stomach stapling, lap banding, stomach reduction and other techniques that reduce the amount of food the stomach can hold. For instance, in the United States, the American Society of Bariatric Surgery (ASBS) reports that the year 2000 saw an estimated 37,700 surgeries to restrict the size of a patient's stomach. But in 2006, the most recent year for which statistics are available, there were 177,600 such operations. Usually, by 18 months after the surgery, patients report having lost anywhere from 45 to 136 kg (100 to 300 pounds).

Body lifting

Food-restriction operations to the stomach have several side effects. One such undesirable side effect that is very bothersome and visible is the loose, hanging skin that covers much of a weight loss patient's body. Because hundreds of pounds have stretched the patient's skin to the maximum, it has lost its elasticity and the ability to spring back. Instead, the newly slimmed patient must deal with so much extra hanging skin, he or she can actually stumble on an overhanging panniculus, the large apron of skin hanging from the stomach that can cover the pubis and groin areas. Notably, many extra inches (and sometimes, feet) of floppy skin hang from the upper arms, the chest, the stomach, the upper thighs and buttocks.

Most people who have lost massive amounts of weight complain about the difficulty of getting their fleshy arms into sleeves and their excess stomach skin tucked into clothing. Most women in this state condition require a mastopexy, or breast lift, often in conjunction with breast implants. Men who have body shaping surgery usually undergo male breast reduction surgery to remove the pendulous skin hanging from their chests.

The extra rolls and sheets of skin rub against each other, creating many spots of irritation and leading to hygienic difficulties. The masses of excess skin also make any form of exercise difficult.

While the procedure is expensive, often running in the neighbourhood of US$20,000-50,000 for an entire body, it usually leaves long, visible scars on the arms, chest, stomach and legs. Most surgeons break the surgical task into an upper, and a lower, body lift. A lower body lift removes the sagging skin on the back, abdomen, buttocks and thighs while the upper body procedure removes loose skin from the arms, breasts and chest.

Potential risks and side-effects

Body lifting is not lightly undertaken. The process requires a commitment on the part of the patient who must stay with the program through bariatric surgery, during the 18 months required for weight loss, then the body contouring procedures and recovery. Often, beginning to end takes three years. A single body lifting operation can require seven to 10 hours under general anesthesia, blood transfusions and often, another surgeon to assist. Plastic surgeons advise patients that body shaping is not an obesity operation. A patient who is more than 50 percent over his or her ideal weight must first drop as many pounds as possible before proceeding. Other medical considerations the plastic surgeon must take into account include scars already present on the body, current medical conditions like heart disease or bleeding disorders, and if the patient smokes. Other possible risks include infections and reactions and complications due to being under anesthesia for longer than six hours. The patient may also experience seroma, a buildup of fluid; dehiscence (wound separation) and deep vein thrombosis (blood clots forming in the legs.) Rare complications include lymphatic injury and major wound dehiscence. The hospital stay for the procedure can require from one to four days while recovery can require about a month for a total body lift. Essentially, the patient trades "skin for scars". But skin relaxation is always a risk and may not be stopped with a single procedure. Reputable plastic surgeons will explain all the risks and complications in full to their patients and even encourage a second or third consultation visit with other plastic surgeons to get additional views on such a major undertaking.

Body lifting surgical procedures

While body shaping can be done in one marathon session, it is usually broken into one to three surgical stages, with the patient under general anesthesia. But if the patient is a smoker, has a history of deep venous thrombosis or clotting disorders along with a high BMI and other medical risk factors, the surgeon will probably insist on doing several short procedures in a hospital setting to insure maximum safety for the patient.

The following are the individual components of body contouring:

Arm lift or brachioplasty. The extra flesh on the arms of bariatric patients virtually always appears on the underside of the upper arm and is sometimes referred to as "bat wings". Surgeons make incisions made from the armpit to the elbow to remove the skin and create a more pleasing contour. Consequently, surgeons open the arm on its underside so that the resulting scar is fairly well hidden. A brachioplasty procedure can employ some liposuction after the incision is made. With the arm opened, the surgeon pulls the skin tight and then trims away the excess skin which, depending on the patient, can be a pound of skin per arm or more.

Breast lift or mastopexy. By trimming excess tissue from the upper breast, the surgeon can move breasts which usually droop to the umbillicus to a more upright and full position. The procedure also often requires an implant to make up for lost fat and tissue inside the breast. Scars on women are almost always hidden inside the area covered by the bra.

Stomach lift or abdominoplasty. Excess skin hanging down over the pubic region is often the distorting feature that most concerns and bothers patients. The stomach pannus retains moisture, and causes rashes due to skin rubbing against itself which usually leads to poor hygiene. While the surgical procedure to remove it is known as a panniculectomy, there is often more work to be done for patients who suffer from large amounts of hanging skin. To provide improved contours on the waist, back and flanks, surgeons sometimes perform a belt lipectomy, (also known as a torsoplasty or a circumferential lipectomy). The incision goes all the way around the patient's midsection at the level of the lower waist. The surgeon uses more liposuction on the stomach and flanks while trimming excess skin from the patient's back and sides as well. The abdominoplasty and belt lipectomy incisions are placed so that the resulting scar is hidden within most underwear and swimsuits.

Lower body lift trims excess skin on the buttocks and thighs. For an inner thigh lift, the surgeon makes an incision high on the inner leg, starting near the groin and continuing down to the knee. Some fat may be removed with liposuction. The surgeon then removes excess skin and redrapes the remaining skin before closing the long incision, leaving the patient with tighter and more attractive thighs.

The outer thigh and buttock can be lifted through a hip-to-hip incision across the back, above the buttocks.

Nonsurgical methods

Nonsurgical body contouring is a rapidly growing field. Common methods used include low-level laser therapy (LLLT), cryolipolysis, radiofrequency energy, suction massage, and high-frequency focused ultrasound.

Now, doctors are able to use non-invasive technology to achieve a reduction in size of certain body areas, increased tone in lax or redundant skin and a diminished appearance of cellulite.

Usual results

While considered major surgery, the outcome of body shaping can require several months to see the full effects of the procedure.

When researchers at the University of Pittsburgh enrolled 18 bariatric patients just before the subjects decided to undergo body contouring, their average age was 46, plus or minus ten years. The researchers studied the patients' body perception, quality of life and mood at three and six months after the body contouring procedures. They found the subjects' quality of life improved and significantly enhanced their moods which had remained stable at the six-month point. Most body lifting patients return to non-strenuous work in about two to three weeks.

Except for brachioplasty, virtually all body shaping procedures require the patient to wear a support or compression garment for two to six weeks. The garment speeds and aids in healing.

Patients can usually drive again within one to three weeks, depending on the extent of the surgery, their health and general robustness.

See also

• Liposuction
• Bariatrics

References

Further reading

• Soldin, M; Mughal, M; Al-Hadithy, N (2014). "National Commissioning Guidelines: Body contouring surgery after massive weight loss". Journal of Plastic, Reconstructive & Aesthetic Surgery 67 (8): 1076-81. doi:10.1016/j.bjps.2014.04.031. PMID 24909630. 
• Hasanbegovic, E; Sørensen, JA (2014). "Complications following body contouring surgery after massive weight loss: A meta-analysis". Journal of Plastic, Reconstructive & Aesthetic Surgery 67 (3): 295-301. doi:10.1016/j.bjps.2013.10.031. PMID 24211118. 
• Azin, A; Zhou, C; Jackson, T; Cassin, S et al. (2014). "Body contouring surgery after bariatric surgery: A study of cost as a barrier and impact on psychological well-being". Plastic and Reconstructive Surgery 133 (6): 776e-82e. doi:10.1097/PRS.0000000000000227. PMID 24867737. 
• Hurwitz, Dennis J. Total Body Lift: Reshaping the Breasts, Chest, Arms, Thighs, Hips. Waist, Abdomen & Knees after Weight Loss, Aging & Pregnancies. New York: M.D. Publish. 
• Capella, Joseph; Rubin, Peter; Sebastian, Jeffrey. Body Contouring Surgery After Weight Loss. Omaha, NE: Addicus Books. 
• Jalian, HR; Avram, MM (2012). "Body contouring: The skinny on noninvasive fat removal" (PDF). Seminars in Cutaneous Medicine and Surgery 31 (2): 121-5. doi:10.1016/j.sder.2012.02.004. 

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Gastric bypass surgery refers to a surgical procedure in which the stomach is divided into a small upper pouch and a much larger lower "remnant" pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several different ways to reconnect the intestine, thus leading to several different gastric bypass (GBP) procedures. Any GBP leads to a marked reduction in the functional volume of the stomach, accompanied by an altered physiological and physical response to food.

The operation is prescribed to treat morbid obesity (defined as a body mass index greater than 40), type 2 diabetes, hypertension, sleep apnea, and other comorbid conditions. Bariatric surgery is the term encompassing all of the surgical treatments for morbid obesity, not just gastric bypasses, which make up only one class of such operations. The resulting weight loss, typically dramatic, markedly reduces comorbidities. The long-term mortality rate of gastric bypass patients has been shown to be reduced by up to 40%. As with all surgery, complications may occur. A study from 2005 to 2006 revealed that 15% of patients experience complications as a result of gastric bypass, and 0.5% of patients died within six months of surgery due to complications.

Uses

Gastric bypass is indicated for the surgical treatment of morbid obesity, a diagnosis which is made when the patient is seriously obese, has been unable to achieve satisfactory and sustained weight loss by dietary efforts, and suffers from comorbid conditions which are either life-threatening or a serious impairment to the quality of life.

Prior to 1991, clinicians interpreted serious obesity as weighing at least 100 pounds (45 kg) more than the "ideal body weight", an actuarially-determined body-weight at which one was estimated to be likely to live the longest, as determined by the life-insurance industry. This criterion failed for persons of short stature.

In 1991, the National Institutes of Health (NIH) sponsored a consensus panel whose recommendations have set the current standard for consideration of surgical treatment, the body mass index (BMI). The BMI is defined as the body weight (in kilograms), divided by the square of the height (in meters). The result is expressed as a number - usually between 15 and 70 - in units of kilograms per square meter.

The Consensus Panel of the National Institutes of Health (NIH) recommended the following criteria for consideration of bariatric surgery, including gastric bypass procedures:

• people who have a BMI of 40 or higher
• people with a BMI of 35 or higher with one or more related comorbid conditions

The Consensus Panel also emphasized the necessity of multidisciplinary care of the bariatric surgical patient by a team of physicians and therapists to manage associated comorbidities and nutrition, physical activity, behavior, and psychological needs. The surgical procedure is best regarded as a tool which enables the patient to alter lifestyle and eating habits, and to achieve effective and permanent management of obesity and eating behavior.

Since 1991, major developments in the field of bariatric surgery, particularly laparoscopy, have outdated some of the conclusions of the NIH panel. In 2004 the American Society for Bariatric Surgery (ASBS) sponsored a consensus conference which updated the evidence and the conclusions of the NIH panel. This conference, composed of physicians and scientists of both surgical and non-surgical disciplines, reached several conclusions, including:

• bariatric surgery is the most effective treatment for morbid obesity
• gastric bypass is one of four types of operations for morbid obesity
• laparoscopic surgery is equally effective and as safe as open surgery
• patients should undergo comprehensive preoperative evaluation and have multi-disciplinary support for optimum outcome

Surgical techniques

The gastric bypass, in its various forms, accounts for a large majority of the bariatric surgical procedures performed. It is estimated that 200,000 such operations were performed in the United States in 2008. An increasing number of these operations are now performed by limited access techniques, termed "laparoscopy".

Laparoscopic surgery is performed using several small incisions, or ports: one to insert a surgical telescope connected to a video camera, and others to permit access of specialized operating instruments. The surgeon views his operation on a video screen. Laparoscopy is also called limited access surgery, reflecting the limitation on handling and feeling tissues and also the limited resolution and two-dimensionality of the video image. With experience, a skilled laparoscopic surgeon can perform most procedures as expeditiously as with an open incision--with the option of using an incision should the need arise.

The Roux-en-Y laparoscopic gastric bypass, first performed in 1993, is regarded as one of the most difficult procedures to perform by limited access techniques, but use of this method has greatly popularized the operation due to associated benefits such as a shortened hospital stay, reduced discomfort, shorter recovery time, less scarring, and minimal risk of incisional hernia.

Essential features

The gastric bypass procedure consists of:

• Creation of a small, (15-30 mL/1-2 tbsp) thumb-sized pouch from the upper stomach, accompanied by bypass of the remaining stomach (about 400 mL and variable). This restricts the volume of food which can be eaten. The stomach may simply be partitioned (like a wall between two rooms in a house or two office cubicles next to each other with a partition wall in between them - and typically by the use of surgical staples), or it may be totally divided into two separate/separated parts (also with staples). Total division (separate/separated parts) is usually advocated to reduce the possibility that the two parts of the stomach will heal back together ("fistulize") and negate the operation.
• Re-construction of the GI tract to enable drainage of both segments of the stomach. The particular technique used for this reconstruction produces several variants of the operation, differing in the lengths of small intestine used, the degree to which food absorption is affected, and the likelihood of adverse nutritional effects. Usually, a segment of the small bowel (called the alimentary limb) is brought up to the proximal remains of the stomach.

Variations of the gastric bypass

Gastric bypass, Roux en-Y (proximal)

This variant is the most commonly employed gastric bypass technique, and is by far the most commonly performed bariatric procedure in the United States. The small intestine is divided approximately 45 cm (18 in) below the lower stomach outlet and is re-arranged into a Y-configuration, enabling outflow of food from the small upper stomach pouch via a "Roux limb". In the proximal version, the Y-intersection is formed near the upper (proximal) end of the small intestine. The Roux limb is constructed using 80-150 cm (31-59 in) of the small intestine, preserving the rest (and the majority) of it for absorbing nutrients. The patient will experience very rapid onset of the stomach feeling full, followed by a growing satiety (or "indifference" to food) shortly after the start of a meal.

Gastric bypass, Roux en-Y (distal)

The small intestine is normally 6-10 m (20-33 ft) in length. As the Y-connection is moved further down the gastrointestinal tract, the amount available to fully absorb nutrients is progressively reduced, traded for greater effectiveness of the operation. The Y-connection is formed much closer to the lower (distal) end of the small intestine, usually 100-150 cm (39-59 in) from the lower end, causing reduced absorption (malabsorption) of food: primarily of fats and starches, but also of various minerals and the fat-soluble vitamins. The unabsorbed fats and starches pass into the large intestine, where bacterial actions may act on them to produce irritants and malodorous gases. These larger effects on nutrition are traded for a relatively modest increase in total weight loss.

"Mini-gastric bypass" (MGB)

The mini gastric bypass procedure was first developed by Dr Robert Rutledge from the USA in 1997, as a modification of the standard Billroth II procedure. A mini gastric bypass creates a long narrow tube of the stomach along its right border (the lesser curvature). A loop of the small gut is brought up and hooked to this tube at about 180 cm from the start of the intestine

Numerous studies show that the loop reconstruction (Billroth II gastrojejunostomy) works more safely when placed low on the stomach, but can be a disaster when placed adjacent to the esophagus. Today thousands of "loops" are used for surgical procedures to treat gastric problems such as ulcers, stomach cancer, and injury to the stomach. The mini gastric bypass uses the low set loop reconstruction and thus has rare chances of bile reflux.

The MGB has been suggested as an alternative to the Roux en-Y procedure due to the simplicity of its construction, and is becoming more and more popular because of low risk of complications and good sustained weight loss. It has been estimated that 15.4% of weight loss surgery in Asia is now performed via the MGB technique.

Physiology

The gastric bypass reduces the size of the stomach by well over 90%. A normal stomach can stretch, sometimes to over 1000 mL, while the pouch of the gastric bypass may be 15 mL in size. The gastric bypass pouch is usually formed from the part of the stomach which is least susceptible to stretching. That, and its small original size, prevents any significant long-term change in pouch volume. What does change, over time, is the size of the connection between the stomach and intestine and the ability of the small intestine to hold a greater volume of food. Over time, the functional capacity of the pouch increases; by that time, weight loss has occurred, and the increased capacity should serve to allow maintenance of a lower body weight.

When the patient ingests just a small amount of food, the first response is a stretching of the wall of the stomach pouch, stimulating nerves which tell the brain that the stomach is full. The patient feels a sensation of fullness, as if they had just eaten a large meal--but with just a thimble-full of food. Most people do not stop eating simply in response to a feeling of fullness, but the patient rapidly learns that subsequent bites must be eaten very slowly and carefully, to avoid increasing discomfort or vomiting.

Food is first churned in the stomach before passing into the small intestine. When the lumen of the small intestine comes into contact with nutrients, a number of hormones are released, including cholecystokinin from the duodenum and PYY and GLP-1 from the ileum. These hormones inhibit further food intake and have thus been dubbed "satiety factors". Ghrelin is a hormone that is released in the stomach that stimulates hunger and food intake. Changes in circulating hormone levels after gastric bypass have been hypothesized to produce reductions in food intake and body weight in obese patients. However, these findings remain controversial, and the exact mechanisms by which gastric bypass surgery reduces food intake and body weight have yet to be elucidated.

For example, it is still widely perceived that gastric bypass works by mechanical means, i.e. food restriction and/or malabsorption. Recent clinical and animal studies, however, have indicated that these long-held inferences about the mechanisms of Roux en-Y gastric bypass (RYGB) may not be correct. A growing body of evidence suggests that profound changes in body weight and metabolism resulting from RYGB cannot be explained by simple mechanical restriction or malabsorption. One study in rats found that RYGB induced a 19% increase in total and a 31% increase in resting energy expenditure, an effect not exhibited in vertical sleeve gastrectomy rats. In addition, pair-fed rats lost only 47% as much weight as their RYGB counterparts. Changes in food intake after RYGB only partially account for the RYGB-induced weight loss, and there is no evidence of clinically significant malabsorption of calories contributing to weight loss. Thus, it appears RYGB affects weight loss by altering the physiology of weight regulation and eating behavior rather than by simple mechanical restriction or malabsorption.

To gain the maximum benefit from this physiology, it is important that the patient eat only at mealtimes, 5 to 6 small meals daily, and not graze between meals, which can effectively "bypass the bypass". Concentration on obtaining 80-100 g of daily protein is necessary. Meals after surgery are 1/4-1/2 cup, slowly getting to 1 cup by one year. This requires a change in eating behavior and alteration of long-acquired habits for finding food. In almost every case where weight gain occurs late after surgery, capacity for a meal has not greatly increased. Some assume the cause of regaining weight must be the patient's fault, e.g. eating between meals with high-caloric snack foods, though this has been debated. Others believe it is an unpredictable failure or limitation of the surgery for certain patients (e.g. reactive hypoglycemia). Of course, there may be no operation which can completely counteract the adverse effects of destructive eating behavior. This surgery is only a tool and as with most tools, if not used correctly, it can be of no use.

Complications

Any major surgery involves the potential for complications--adverse events which increase risk, hospital stay, and mortality. Some complications are common to all abdominal operations, while some are specific to bariatric surgery.

Mortality and complication rates

The overall rate of complications during the 30 days following surgery ranges from 7% for laparoscopic procedures to 14.5% for operations through open incisions. One study on mortality revealed a 0% mortality rate out of 401 laparoscopic cases, and 0.6% out of 955 open procedures (6 Deaths). Similar mortality rates--30-day mortality of 0.11% (364 deaths), and 90-day mortality of 0.3%--have been recorded in the U.S. Centers of Excellence program, the results being from 33,117 operations at 106 centers.

Mortality and complications are affected by pre-existing risk factors such as degree of obesity, heart disease, obstructive sleep apnea, diabetes mellitus, and history of prior pulmonary embolism. It is also affected by the experience of the operating surgeon: the learning curve for laparoscopic bariatric surgery is estimated to be about 100 cases. Supervision and experience is important when selecting a surgeon, as the way a surgeon becomes experienced in dealing with problems is by encountering and solving them.

Complications of abdominal surgery

Infection

Infection of the incisions or of the inside of the abdomen (peritonitis, abscess) may occur due to release of bacteria from the bowel during the operation. Nosocomial infections, such as pneumonia, bladder or kidney infections, and sepsis (blood-borne infection) are also possible. Effective short-term use of antibiotics, diligent respiratory therapy, and encouragement of activity within a few hours after surgery can reduce the risks of infections.

Venous thromboembolism

Any injury, such as a surgical operation, causes the body to increase the coagulation of the blood. Simultaneously, activity may be reduced. There is an increased probability of formation of clots in the veins of the legs, or sometimes the pelvis, particularly in the morbidly obese patient. A clot which breaks free and floats to the lungs is called a pulmonary embolus, a very dangerous occurrence. Blood thinners are commonly administered before surgery to reduce the probability of this type of complication.

Hemorrhage

Many blood vessels must be cut in order to divide the stomach and to move the bowel. Any of these may later begin bleeding, either into the abdomen (intra-abdominal hemorrhage), or into the bowel itself (gastrointestinal hemorrhage). Transfusions may be needed, and re-operation is sometimes necessary. Use of blood thinners to prevent venous thromboembolic disease may actually increase the risk of hemorrhage slightly.

Hernia

A hernia is an abnormal opening, either within the abdomen or through the abdominal wall muscles. An internal hernia may result from surgery and re-arrangement of the bowel, and is a cause of bowel obstruction. Antecolic antegastric Roux-en-Y gastric bypass surgery has been estimated to result in internal hernia in 0.2% of cases, mainly through Petersen's defect. An incisional hernia occurs when a surgical incision does not heal well; the muscles of the abdomen separate and allow protrusion of a sac-like membrane, which may contain bowel or other abdominal contents, and which can be painful and unsightly. The risk of abdominal-wall hernia is markedly decreased in laparoscopic surgery.

Bowel obstruction

Abdominal surgery always results in some scarring of the bowel, called adhesions. A hernia, either internal or through the abdominal wall, may also result. When bowel becomes trapped by adhesions or a hernia, it may become kinked and obstructed, sometimes many years after the original procedure. An operation is usually necessary to correct this problem.

Complications of gastric bypass

Anastomotic leakage

An anastomosis is a surgical connection between the stomach and bowel, or between two parts of the bowel. The surgeon attempts to create a water-tight connection by connecting the two organs with either staples or sutures, either of which actually makes a hole in the bowel wall. The surgeon will rely on the body's natural healing abilities and its ability to create a seal, like a self-sealing tire, to succeed with the surgery. If that seal fails to form for any reason, fluid from within the gastrointestinal tract can leak into the sterile abdominal cavity and give rise to infection and abscess formation. Leakage of an anastomosis can occur in about 2% of Roux-en-Y gastric bypass and less than 1% in mini gastric bypass. Leaks usually occur at the stomach-intestine connection (gastro-jejunostomy). There is a change in the drain fluid contents from serous (before the leak) to fecal/bilious (after the leak). Usually significant leaks need urgent re-operation. Sometimes a minor leakage can be treated with antibiotics only. It is usually safer to re-operate if an infection cannot be definitely controlled immediately.

Anastomotic stricture

As the anastomosis heals, it forms scar tissue, which naturally tends to shrink ("contract") over time, making the opening smaller. This is called a "stricture". Usually, the passage of food through an anastomosis will keep it stretched open, but if the inflammation and healing process outpaces the stretching process, scarring may make the opening so small that even liquids can no longer pass through it. The solution is a procedure called gastroendoscopy, and stretching of the connection by inflating a balloon inside it. Sometimes this manipulation may have to be performed more than once to achieve lasting correction.

Anastomotic ulcer

Ulceration of the anastomosis occurs in 1-16% of patients. Possible causes of such ulcers are:

• Restricted blood supply to the anastomosis (compared to the blood supply available to the original stomach)
• Anastomosis tension
• Gastric acid
• The bacteria Helicobacter pylori
• Smoking
• Use of non-steroidal anti-inflammatory drugs

This condition can be treated with:

• Proton pump inhibitors, e.g. esomeprazole
• A cytoprotectant and acid buffering agent, e.g. sucralfate
• Temporary restriction of the consumption of solid foods

Dumping syndrome

Normally, the pyloric valve at the lower end of the stomach regulates the release of food into the bowel. When the gastric bypass patient eats a sugary food, the sugar passes rapidly into the intestine, where it gives rise to a physiological reaction called dumping syndrome. The body will flood the intestines in an attempt to dilute the sugars. An affected person may feel their heart beating rapidly and forcefully, break into a cold sweat, get a feeling of butterflies in the stomach, and may have an anxiety attack. The person usually has to lie down, and could be very uncomfortable for 30-45 minutes. Diarrhea may then follow.

Nutritional deficiencies

Nutritional deficiencies are common after gastric bypass surgery, and are often not recognized. They include:

• Secondary hyperparathyroidism due to inadequate absorption of calcium may occur for GBP patients. Calcium is primarily absorbed in the duodenum, which is bypassed by the surgery. Most patients can achieve adequate calcium absorption by supplementation with vitamin D and calcium citrate (carbonate may not be absorbed--it requires an acidic stomach, which is bypassed).
• Iron frequently is seriously deficient, particularly in menstruating females, and must be supplemented. Again, it is normally absorbed in the duodenum. Ferrous sulfate can cause considerable GI distress in normal doses; alternatives include ferrous fumarate, or a chelated form of iron. Occasionally, a female patient develops severe anemia, even with supplements, and must be treated with parenteral iron. The signs of iron deficiency include: brittle nails, an inflamed tongue, constipation, depression, headaches, fatigue, and mouth lesions.
• Signs and symptoms of zinc deficiency may also occur such as: acne, eczema, white spots on the nails, hair loss, depression, amnesia, and lethargy.
• Deficiency of thiamine (also known as vitamin B₁) brings the risk of permanent neurological damage (i.e. Wernicke's encephalopathy or polyneuropathy). Signs of thiamin deficiency are heart failure, memory loss, numbness of the hands, constipation, and loss of appetite.
• Vitamin B₁₂ requires intrinsic factor from the gastric mucosa to be absorbed. In patients with a small gastric pouch, it may not be absorbed, even if supplemented orally, and deficiencies can result in pernicious anemia and neuropathies. Vitamin B₁₂ deficiency is quite common after gastric bypass surgery with reported rates of 30% in some clinical trials. Sublingual B₁₂ (cyanocobalamin) appears to be adequately absorbed. In cases where sublingual B₁₂ does not provide sufficient amounts, injections may be needed.
• Protein malnutrition is a real risk. Some patients suffer troublesome vomiting after surgery, until their GI tract adjusts to the changes, and cannot eat adequate amounts even with 6 meals a day. Many patients require protein supplementation during the early phases of rapid weight loss to prevent excessive loss of muscle mass. Hair loss is also a risk of protein malnutrition.
• Vitamin A deficiencies generally occur as a result of fat-soluble vitamins deficiencies. This often comes after intestinal bypass procedures such as jejunoileal bypass (no longer performed) or biliopancreatic diversion/duodenal switch procedures. In these procedures, fat absorption is markedly impaired. There is also the possibility of a vitamin A deficiency with use of the weight-loss medication orlistat (marketed as Xenical and Alli).
• Folate deficiency is also a common occurrence in gastric bypass surgery patients.

Nutritional effects

After surgery, patients feel fullness after ingesting only a small volume of food, followed soon thereafter by a sense of satiety and loss of appetite. Total food intake is markedly reduced. Due to the reduced size of the newly created stomach pouch, and reduced food intake, adequate nutrition demands that the patient follow the surgeon's instructions for food consumption, including the number of meals to be taken daily, adequate protein intake, and the use of vitamin and mineral supplements. Calcium supplements, iron supplements, protein supplements, multi-vitamins (sometimes pre-natal vitamins are best), and vitamin B₁₂ (cyanocobalamin) supplements are all very important to the post-operative bypass patient.

Total food intake and absorbance rate of food will rapidly decline after gastric bypass surgery, and the number of acid-producing cells lining the stomach increases. Doctors often prescribe acid-lowering medications to counteract the high acidity levels. Many patients then experience a condition known as achlorhydria, where there is not enough acid in stomach. As a result of the low acidity levels, patients can develop an overgrowth of bacteria. A study conducted on 43 post-operative patients revealed that almost all of the patients tested positive for a hydrogen breath test, which indicated an overgrowth of bacteria in the small intestine. Bacterial overgrowth causes the gut ecology to change and induces nausea and vomiting. Recurring nausea and vomiting eventually change the absorbance rate of food, contributing to the vitamin and nutrition deficiencies common in post-operative gastric bypass patients.

Protein nutrition

Proteins are essential food substances, contained in foods such as meat, fish and poultry, dairy products, soy, nuts, and eggs. With reduced ability to eat a large volume of food, gastric bypass patients must focus on eating their protein requirements first, and with each meal. In some cases, surgeons may recommend use of a liquid protein supplement. Powdered protein supplements added to smoothies or any food can be an important part of the post-op diet.

Calorie nutrition

The profound weight loss which occurs after bariatric surgery is due to taking in much less energy (calories) than the body needs to use every day. Fat tissue must be burned to offset the deficit, and weight loss results. Eventually, as the body becomes smaller, its energy requirements are decreased, while the patient simultaneously finds it possible to eat somewhat more food. When the energy consumed is equal to the calories eaten, weight loss will stop. Proximal GBP typically results in loss of 60-80% of excess body weight, and very rarely leads to excessive weight loss. The risk of excessive weight loss is slightly greater with distal GBP.

Vitamins

Vitamins are normally contained in foods and supplements. The amount of food eaten after GBP is severely reduced, and vitamin content is correspondingly lowered. Supplements should therefore be taken to complete minimum daily requirements of all vitamins and minerals. Pre-natal vitamins are sometimes suggested by doctors, as they contain more of certain vitamins than most multi-vitamins. Absorption of most vitamins is not seriously affected after proximal GBP, although vitamin B₁₂ may not be well-absorbed in some persons: sublingual preparations of B₁₂ provide adequate absorption. Some studies suggest that GBP patients who took probiotics after surgery are able to absorb and retain higher amounts of B₁₂ than patients who did not take probiotics after surgery. After a distal GBP, fat-soluble vitamins A, D, and E may not be well-absorbed, particularly if fat intake is large. Water-dispersed forms of these vitamins may be indicated on specific physician recommendation. For some patients, sublingual B₁₂ is not enough, and patients may require B₁₂ injections.

Minerals

All versions of the GBP bypass the duodenum, which is the primary site of absorption of both iron and calcium. Iron replacement is essential in menstruating females, and supplementation of iron and calcium is preferable in all patients. Ferrous sulfate is poorly tolerated. Alternative forms of iron (fumarate, gluconate, chelates) are less irritating and probably better absorbed. Calcium carbonate preparations should also be avoided; calcium as citrate or gluconate (with 1200 mg as calcium) has greater bioavailability independent of acid in the stomach, and will likely be better absorbed. Chewable calcium supplements that include vitamin K are sometimes recommended by doctors as a good way to get calcium.

Alcohol metabolism

Post-operative gastric bypass patients develop a lowered tolerance for alcoholic beverages because their altered digestive tract absorbs alcohol at a faster rate than people who have not undergone the surgery. It also takes a post-operative patient longer to reach sober levels after consuming alcohol. In a study conducted on 36 post-operative patients and a control group of 36 subjects (who had not undergone surgery), each subject drank a 5 oz. glass of red wine and had the alcohol in their breath measured to evaluate alcohol metabolism. The gastric bypass group had an average peak alcohol breath level at 0.08%, whereas the control group had an average peak alcohol breath level of 0.05%. It took on average 108 minutes for the gastric bypass patients group to return to an alcohol breath of zero, while it took the control group an average of 72 minutes.

Pica

There have been reported cases in which pica recurs after gastric bypass in patients with a pre-operative history of the disorder, which are possibly due to iron deficiency. Pica is a compulsive tendency to eat substances other than normal food. Some examples would be people eating paper, clay, plaster, ashes, or ice. Low levels of iron and hemoglobin are common in patients who have undergone gastric bypass. One study reported on a female post-operative gastric bypass patient who was consuming eight to ten 32 oz. glasses of ice a day. The patient's blood test revealed iron levels of 2.3 mmol/L and hemoglobin level of 5.83 mmol/L. Normal iron blood levels of adult women are 30 to 126 µg/dL and normal hemoglobin levels are 12.1 to 15.1 g/dl. This deficiency in the patient's iron levels may have led to the increase Pica activity. The patient was then given iron supplements that brought her hemoglobin and iron blood levels to normal levels. After one month, the patient's eating diminished to two to three glasses of ice per day. After one year of taking iron supplements the patient's iron and hemoglobin levels remained in a normal range and the patient reported that she did not have any further cravings for ice.

Results and health benefits of gastric bypass

Weight loss of 65-80% of excess body weight is typical of most large series of gastric bypass operations reported. The medically more significant effects include a dramatic reduction in comorbid conditions:

• Hyperlipidemia is corrected in over 70% of patients.
• Essential hypertension is relieved in over 70% of patients, and medication requirements are usually reduced in the remainder.
• Obstructive sleep apnea improves markedly with weight loss and bariatric surgery may be curative for sleep apnea. Snoring also reduces in most patients.
• Type 2 diabetes is reversed in up to 90% of patients usually leading to a normal blood-sugar level without medication, sometimes within days of surgery. Furthermore, Type 2 diabetes is prevented by more than 30-fold in patients with pre-diabetes. All these findings were first reported by Walter Pories and Jose F. Caro.
• Gastroesophageal reflux disease is relieved in almost all patients.
• Venous thromboembolic disease signs such as leg swelling are typically alleviated.
• Lower-back pain and joint pain are typically relieved or improved in nearly all patients.

A study in a large comparative series of patients showed an 89% reduction in mortality over the five years following surgery, compared to a non-surgically treated group of patients.

Concurrently, most patients are able to enjoy greater participation in family and social activities.

Cost of gastric bypass

The patient's out of pocket cost for Roux-en-Y gastric bypass surgery varies widely depending on method of payment, region, surgical practice and hospital in which the procedure is performed.

Methods of payment in the United States include private insurance (Individual & Family coverage, Small Group coverage through an employer (Under 50 full-time employees) and Large Group coverage through an employer (50 or more full-time employees), public insurance (Medicare and Medicaid) and self-pay. Out of pocket costs for a patient with private or public insurance that specifically list bariatric surgery as a covered benefit include several insurance-policy-specific parameters such as deductible levels, coinsurance percentages, copay amounts and out of pocket limits.

Patients without insurance must pay for surgery directly (or through a third party lender), and total out of pocket costs will depend on the surgical practice they choose and the hospital in which the surgical practice performs the procedure. On average, the total cost of gastric bypass surgery is about $24,000 in the United States, although on a state-specific level it ranges from an average of $15,000 (Arkansas) to an average of $57,000 (Alaska).

Living with gastric bypass

Gastric bypass surgery has an emotional and physiological impact on the individual. Many who have undergone the surgery suffer from depression in the following months as a result of a change in the role food plays in their emotional well-being. Strict limitations on the diet can place great emotional strain on the patient. Energy levels in the period following the surgery can be low, both due to the restriction of food intake and negative changes in emotional state. It may take as long as three months for emotional levels to rebound. Muscular weakness in the months following surgery is also common. This is caused by a number of factors, including a restriction on protein intake, a resulting loss in muscle mass and decline in energy levels. Muscle weakness may result in balance problems, difficulty climbing stairs or lifting heavy objects, and increased fatigue following simple physical tasks. Many of these issues pass over time as food intake gradually increases. However, the first months following the surgery can be very difficult, an issue not often mentioned by physicians suggesting the surgery. The benefits and risks of this surgery are well established; however, the psychological effects are not well understood.

Even if physical activity is increased patients may still harbor long term psychological effects due to excess skin and fat. Often bypass surgery is followed up with "body lifts" of skin and liposuction of fatty deposits. These extra surgeries have their own inherent risks but are even more dangerous when coupled with the typical nutritional deficiences that accompany convalescing gastric bypass patients.

Surgeon accreditation

The American Society for Metabolic & Bariatric Surgery lists bariatric programs and surgeons in its "Centers of Excellence" network, while the American College of Surgeons accredits providers through its Bariatric Surgery Center Network. For listings of surgeons and centers in other countries, the International Federation for the Surgery of Obesity and Metabolic Disorders lists medical associations by country.

See also

• Adjustable gastric banding surgery
• Duodenal Switch surgery
• Vagotomy--Cutting of the vagus nerve to reduce the feeling of hunger
• StomaphyX--Revisional, natural orifice procedure for patients that have regained weight after gastric bypass
• American Society for Bariatric Surgery

References

• Buchwald, H; Cowan, GSM; Pories, WJ (2007), Surgical Management of Obesity, Saunders Elsevier, ISBN 978-1-4160-0089-1 
• Buchwald, H; Consensus Conference, Panel (2005), "Bariatric surgery for morbid obesity: health implications for patients, health professionals, and third-party payers", J Am Coll Surg 200 (4): 593-604, doi:10.1016/j.jamcollsurg.2004.10.039, PMID 15804474 
• Christou, N; Sampalis, J; Liberman, M; Look, D; Auger, S; McLean, A; MacLean, L (2004), "Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients", Ann Surg 240 (3): 416-23; discussion 423-4, doi:10.1097/01.sla.0000137343.63376.19, PMC 1356432, PMID 15319713 
• Wittgrove, AC; Clark, GW (2000), "Laparoscopic Gastric Bypass, Roux en-Y - 500 Patients: Technique and Results with 3-60 Months Follow-up", Obesity Surgery 10 (3): 233-9, doi:10.1381/096089200321643511, PMID 10929154 
• Fontaine, KR; Wang, C; Westfall, AO; Allison, DB et al. (2003), "Years of life lost to obesity", JAMA 289 (2): 187-93, doi:10.1001/jama.289.2.187, PMID 12517229  CS1 maint: Explicit use of et al. (link)
• Peeters, A; Barendregt, J; Willekens, F; Mackenbach, J; Al-Mamun, A; Bonneux, L; NEDCOM, the Netherlands Epidemiology and Demography Compression of Morbidity Research Group (2003), "Obesity in adulthood and its consequences for life expectancy: a life-table analysis", Ann Intern Med 138 (1): 24-32, doi:10.7326/0003-4819-138-1-200301070-00008, PMID 12513041 
• Hutter, MM; Randall, S; Khuri, SF; Henderson, WG; Abbott, WM; Warshaw, AL (2006), "Laparoscopic Versus Open Gastric Bypass for Morbid Obesity: A Multicenter, Prospective, Risk-Adjusted Analysis From the National Surgical Quality Improvement Program", Annals of Surgery 243 (5): 657-66, doi:10.1097/01.sla.0000216784.05951.0b, PMC 1570562, PMID 16633001 

External links

• ASBS Consensus Conference Statement - 2004
• NIH - Gastrointestinal Surgery for Obesity
• NIH Medline Plus - Multiple Links to articles, videos about bariatric surgery
• Metabolic & Weight Loss Surgical Procedures Gallery - Including information on bariatric surgery

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