Archive for the ‘health’ Category

False Pregnancy:

Março 20, 2009

False pregnancy, most commonly termed pseudocyesis in humans and pseudopregnancy in other mammals, is the appearance of clinical and/or subclinical signs and symptoms associated with pregnancy when the person or animal is not pregnant. Clinically, false pregnancy is most common in veterinary medicine (particularly in dogs and mice). False pregnancy in humans is less common, and may sometimes be purely psychological.

In humans (pseudocyesis)

History

Cases of pseudocyesis have been documented since antiquity. Hippocrates gives us the first written account around 300 B.C. when he recorded 12 cases of women with the disorder. Mary I (1516-1558), Queen of England, was perhaps the most famous of western historical examples, who believed on several occasions that she was pregnant, when she was in fact not. Some even attribute the violence that gave her the nickname “Bloody Mary” to be a reaction to her disappointment on realising she was without child. Other medical historians believe that the queen’s physicians mistook fibroid tumors in her uterus for a pregnancy. John Mason Good coined the term pseudocyesis from the Greek words pseudes (false) and kyesis (pregnancy) in 1923.

More recently, pseudocyesis has received attention in popular culture. It has been featured in the television shows CSI: Crime Scene Investigation, Law and Order SVU, The Simpsons, Shameless, General Hospital: Night Shift, and Grey’s Anatomy, in the films Who’s Afraid of Virginia Woolf? and Oldboy, and on the Kaleidoscope album White Faced Lady.

Signs and symptoms

The symptoms of pseudocyesis are similar to the symptoms of true pregnancy and are often hard to distinguish from it. Such natural signs as amenorrhoea, morning sickness, tender breasts, and weight gain may all be present. Many health care professionals can be deceived by the symptoms associated with pseudocyesis. Research shows that 18% of women with pseudocyesis were at one time diagnosed as pregnant by medical professionals.

The hallmark sign of pseudocyesis that is common to all cases is that the affected patient is convinced that she is pregnant. Abdominal distension is the most common physical symptom of pseudocyesis (60– 90%). The abdomen expands in the same manner as it does during pregnancy, so that the affected woman looks pregnant. This phenomenon is thought to be caused by buildup of gas, fat, feces, or urine. These symptoms often resolve under general anesthesia and the woman’s abdomen returns to its normal size.

The second most common physical sign of pseudocyesis is menstrual irregularity (50–90%). Women are also reported to experience the sensation of fetal movements known as quickening, even though there is no fetus present (50%-75%). Other common signs and symptoms include gastrointestinal symptoms, breast changes or secretions, labor pains, uterine enlargement, and softening of the cervix. One percent of women eventually experience false labor.

To be diagnosed as true pseudocyesis, the woman must actually believe that she is pregnant. When a woman intentionally and consciously feigns pregnancy, it is termed a simulated pregnancy.

Causes

There are various explanations, none of which is universally accepted. Psychodynamic theories attribute the false pregnancy to emotional conflict. It is thought that an intense desire to become pregnant, or an intense fear of becoming pregnant, can create internal conflicts and changes in the endocrine system, which may explain some of the symptoms of pseudocyesis. Another theory concerns wish-fulfillment. It holds that if a woman desires pregnancy badly enough she may interpret minor changes in her body as signs of pregnancy. Proposed biological mechanisms include the effect of stress on the hypothalamo-pituitary-adrenal axis, constipation, weight gain and the movement of intestinal gas.

Taenia Saginata:

Março 20, 2009
Taenia saginata, the Beef Tapeworm


http://www.healthinplainenglish.com/health/infectious_diseases/tapeworm

Introduction

The beef tapeworm, Taenia saginata, is a cestode parasite acquired in humans through the ingestion of raw or poorly cooked meat of infected cows. These cows have been infected via the ingestion of human feces containing the eggs of the parasite and these cows contain viable cysticercus larvae in the muscle. Humans act as the host only to the adult tapeworms and can grow up to 25 meters in the lumen of the intestine, but are usually closer to 5 meters in length. T. saginata is closely related but distinct from the pork tapeworm, Taenia solium, which comes from eating infected or poorly cooked pig. Yet another tapeworm, T. asiatica, has been recently distinguished from T. saginata over the past 15 years. A study by Eom and Jun estimated a 4.8% genetic divergence between the two tapeworms. The mitochondrial genomes of the two tapeworms were amplified using PCR and restriction maps were constructed using 13 different restriction enzymes. In T. saginata, the tapeworm is very flexible and fragile and does not obstruct the intestine. The beef tapeworm is found all over the world, including the United States, and is often found in many countries to have greater prevalence than that of T. solium.

Agent

Binomial name: Taenia saginata

Classification and Taxonomy:

Kingdom: Animalia
Phylum: Platyhelminthes
Class: Cestodes
Order: Cyclophyllidea
Family: Taeniidae
Genus: Taenia
Subgenus: Taeniarhynchus
Species: saginata

Synonyms

Beef tapeworm, “unarmed” tapeworm

History of Discovery

Taenia saginata was first distinguished from its close relative Taenia solium by Goeze in 1782. The first report of T. saginata was in 1700 by Audry, but was unable to distinguish the proglottids of the two tapeworms. Goeze was the first to correctly describe the worm as he did in his treatise on helminthology. Leuckart was the first to show experimentally that proglottids of T. saginata fed to calfs developed into cysticerci in the calf’s muscles in 1863. Lastly, Oliver was the first to discover that when humans ingested “bladder worms,” they developed adult T. saginata.

Contact Information

Jon Wong, Class of ’06, jonwong@stanford.edu
Stanford University
Parasites & Pestilence: Infectious Public Health Challenges
Prof. D. Scott Smith, ssmith@stanford.edu


This site was created for Human Biology 103: Parasites & Pestilence at Stanford University. Last updated 5/23/06.