Wednesday, March 9, 2011

Genetic Engineering Based(A Plasmid)

the DNA of any transmissible agent (e.g. plasmid or virus) into which a segment of foreign DNA can be spliced in order to introduce the foreign DNA into cells of the agent's normal host and promote its replication and transcription therein. (1) Plasmid vectors contain (i) an origin of replication, so that the plasmid can be replicated; (ii) an antibiotic resistance gene to allow selection of transformed host cells; (iii) often, a ‘polylinker’ containing several different restriction enzyme recognition sites and a second marker gene (e.g. lacZ; see X‐gal), which will be inactivated when foreign DNA is inserted therein, thus allowing identification of transformants bearing plasmids containing inserts, rather than ‘empty’ vectors. Examples include pBR322 and the pUC vectors. See also expression vectors. (2) Bacteriophage vectors, usually based on lambda phage, can accommodate longer fragments of foreign DNA. In insertion vectors (e.g. λEMBL4) the foreign DNA is inserted into the phage DNA whole in replacement vectors (e.g. λEMBL4) the foreign DNA is ligated between two phage fragments, or arms. (3) Hybrid vectors, cosmids, phagemids and phasmids , with features of both plasmids and phage, have also been constructed.


http://science.jrank.org/pages/27228/cloning-vector-or-cloning-vehicle.html 

Leukaemia Treatment 'Cures' Man of HIV

An HIV positive man who received a bone marrow transplant after developing leukaemia appears to have been cured of HIV.

The American man in his forties, was living in Berlin when he developed acute myeloid leukaemia. When chemotherapy failed to treat his condition, he was given two bone marrow stem cell transplants chosen from a donor who had a natural genetic resistance to HIV.

Around one to three in every hundred people have a gene mutation which gives them a natural resistance to HIV. The virus can only infect human cells by interacting with two 'receptors' located on the surface of the cell, known as the CD4 and CCR5 receptors. However, a small minority of people with a genetic mutation lack the CCR5 receptor, making it extremely difficult for the virus to enter their cells.
The HIV patient's doctors deliberately chose a bone marrow donor with the gene mutation.
Three years on and the man is free of both HIV and leukaemia and is not being treated with anti-retroviral medicines. No trace of the virus has been found in the blood or other parts of the body where HIV can hide out such as the intestines, lymph nodes or the brain.
And all of the patient's new blood and bone marrow cells are of the HIV-resistant kind, without the CCR5 receptor.
However, as bone marrow transplants are risky and complicated procedures, they cannot be widely used as a cure for HIV.

In the journal Blood, the doctors from the Charite University Hospital, Berlin say their findings "strongly suggest that cure of HIV has been achieved" in their patient.

A Female Condom

A female condom is a plastic device that is used during sexual intercourse as a barrier and to reduce the risk of sexually transmitted infections (STIs—such as gonorrhea, syphilis, and HIV) and unintended pregnancy. Invented by Danish MD Lasse Hessel,internally by the receptive partner and physically blocks ejaculated semen from entering  person's body. Female condoms can be used by the receptive partner during anal sex.

The female condom is a thin, soft, loose-fitting sheath with a flexible ring at each end. The inner ring at the closed end of the sheath is used to insert the condom inside the vagina and to hold it in place during intercourse. The rolled outer ring at the open end of the sheath remains outside the vagina and covers part of the external genitalia
A female condom and a male condom should not be used at the same time.

Thursday, October 14, 2010

Drinking During Pregnancy

Pregnant women who have up to two alcoholic drinks per week do not harm their children, a U.K. study shows.
More than 11,500 children and their mothers were included in the study. Mothers were first asked about their alcohol use when the kids were 9 months old. The children were last given a battery of behavioral and cognitive tests when they were 5 years of age.
Women were defined as light drinkers if they had no more than one or two drinks a week. A drink was defined as a very small glass of wine, a half pint of beer, or a small single measure of spirits.

In the U.K., women are advised not to drink at all during the first trimester of their pregnancy and to drink no more than a drink or two a week after that.
In the U.S., pregnant women are strongly advised not to drink at all.
Pressman points out that women who are light drinkers during pregnancy tend to be from households with relatively high incomes. Children in high-income households tend to perform better on behavioral and cognitive tests -- which could mask some possible harms from their mothers' light drinking during pregnancy.


SOURCE>>>
http://www.medicinenet.com/script/main/art.asp?articlekey=120565

Dense Breasts Linked to Breast Cancer Return

Study Shows Dense Breast Tissue May Raise Risk for Cancer Recurrence in Other Breast
Women with an early form of breast cancer are at higher risk for recurrence if their breast tissue appears dense on mammograms, a study shows.
The study also shows the risk of recurrence is more pronounced in the opposing breast.
In the study, of 935 women with an early type of breast cancer known as ductal carcinoma in situ (DCIS) treated with breast-conserving surgery, those women whose breasts appeared dense on their screening mammogram were twice as likely to develop a secondary breast cancer. This risk was about threefold higher for developing a secondary breast cancer in the opposite breast, the study shows.
DCIS refers to breast cancer that has not spread outside the milk glands. During follow-up, 164 had a subsequent breast cancer on the same breast and 59 developed a new cancer in the other breast.
Composed of breast ducts and connective tissue, dense breast tissue looks white on mammograms. Non-dense breast tissue is mainly fat and appears dark gray on a mammogram.
Exactly how dense breast tissue increases breast cancer risk is not fully understood, but breast density may be mediated by certain hormonal and genetic factors. That said, certain hormone therapies can increase or decrease breast density and should be discussed with a doctor if a woman has dense breasts.
According to the National Cancer Institute, women who have a high percentage of dense breast tissue have a higher risk of breast cancer compared to those of a similar age who have a small percentage of or no dense breast tissue.

soure of article>>
http://www.medicinenet.com/script/main/art.asp?articlekey=120651

Bowel Diversion Surgery

Bowel diversion surgery allows stool to safely leave the body when (because of disease or injury) the large intestine is removed or needs time to heal. Bowel is a general term for any part of the small or large intestine.
Some bowel diversion surgeries (those called ostomy surgery)divert the bowel to an opening in the abdomen where a stoma is created. A surgeon forms a stoma by rolling the bowel's end back on itself, like a shirt cuff, and stitching it to the abdominal wall. An ostomy pouch is attached to the stoma and worn outside the body to collect stool.
Other bowel diversion surgeries reconfigure the intestines after damaged portions are removed. For example, after removing the colon, a surgeon can create a colon like pouch out of the last part of the small intestine, avoiding the need for an ostomy pouch.
Cancer, trauma, inflammatory bowel disease (IBD), bowel obstruction, and diverticulitis are all possible reasons for bowel diversion surgery.
Picture of a Stoma.

Which Parts of the Gastrointestinal Tract Are Affected by Bowel Diversion Surgeries?

Bowel diversion surgeries affect the large intestine and often the small intestine.
Small Intestine

The small intestine runs from the stomach to the large intestine and has three main sections: the duodenum, which is the first 10 inches; the jejunum, which is the middle 8 feet; and the ileum, which is the final 12 feet. Bowel diversion surgeries only affect the ileum.
Picture of Small Intestine.

Large Intestine

The large intestine is about 5 feet long and runs from the small intestine to the anus. The colon and rectum are the two main sections of the large intestine. Semisolid digestive waste enters the colon from the small intestine. Gradually, the colon absorbs moisture and forms stool as digestive waste moves toward the rectum. The rectum is about 6 inches long and is located right before the anus. The rectum stores stool, which leaves the body through the anus. The rectum and anus control bowel movements.


For more detail.visit this link>>

http://www.medicinenet.com/bowel_diversion_surgery_ileostomy_colostomy/article.htm

Excess Computer, TV Time Harm Kids Psychologically

Childrens who spent more than two hours a day in front of the TV or computer were at greater risk of having psychological problems than youngsters averaging less screen time, even if the kids also tended to be physically active, new research finds.
It is founf that  the risk of psychological difficulties increased by about 60 percent when kids between 10 and 11 years old spent more than two hours daily watching TV or playing on the computer.
Still, the experts stressed that the study can't discern whether media exposure causes psychological woes in kids, or whether troubled children simply prefer spending time in front of computers or the TV.
Previous studies have linked excessive TV viewing with childhood obesity, and both TV and computer use have been associated with psychological problems and an increase in sedentary time, according to background information in the study.
The researchers had all of the children complete a Strengths and Difficulties questionnaire, which is designed to measure psychological difficulties, such as hyperactivity, inattention, social problems and conduct issues.
Overall, most children reported spending between an hour or two a day on TV and computer use for entertainment. On average, boys were moderately to vigorously active for an average of 83 minutes per day, versus 63 minutes for girls, according to the study.
The study found that children who spent more than two hours a day watching television or using a computer were more likely to have reported psychological difficulties than children who spent less time in front an electronic screen. Kids who watched more than two hours of TV a day had a 61 percent increased risk of psychological difficulties, while those who spent more than two hours on a computer were 59 percent more likely to have psychological difficulties.
When children weren't very active throughout the day, the risk of psychological difficulties went up even more. The risk of psychological problems for sedentary children who watched more than two hours of TV was 70 percent, and for those who spent more than two hours on the computer, the odds were increased 81 percent.
Surprisingly, being highly physically active didn't offer much protection against psychological difficulties if children already clocked more than two hours of screen time each day. The risk of psychological difficulties was still increased by about 50 percent for the highly active group when they spent more than two hours watching TV or using the computer, according to the study.


for more info....visit this link>>
http://www.medicinenet.com/script/main/art.asp?articlekey=120732