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INSIGHT


SALIVA TEST FOR HIV COMPARED WITH BLOOD TEST A SALIVA TEST used to diagnose the Human immunodeficiency virus (HIV) is comparable in accuracy to the traditional blood test. The oral HIV test has become one of the most popular tests because of its acceptability and ease of use. It is also noninvasive, pain- free, convenient and produces results in 20 minutes. A meta-analysis carried


separately for specimens of oral mucosal transudate and whole blood and explored the variability of the PPV within specimen groups in low-prevalence and high-prevalence settings. The results of the analysis


out by scientists at the McGill University (Montreal, QC, Canada) compared studies worldwide and showed that the saliva HIV test had the same accuracy as the blood test for high-risk populations. They computed the positive predicted values (PPVs)


showed that the saliva HIV test, the OraQuick advance rapid HIV-1/2 (OraSure Technologies Inc.; PA, USA) had the same accuracy as the blood test for high-risk populations. The test sensitivity was slightly reduced for low risk populations. The slightly lower sensitivity of the test in oral mucosal transudate compared with blood specimens is probably because of a lower quantity of HIV antibodies in oral mucosal transudate than


CANNABIS DESTROYS CANCER CELLS


SCIENTISTS WORKING IN the UK have revealed that cannabis has the potential to destroy leukemia cells. The team – based at Queen Mary’s School of Medicine and Dentistry in London – have followed up on their previous findings that the main active ingredient in cannabis, tetrahydrocannabinol (THC), has the potential to be used effectively against some forms of cancer. Use of cannabis as a therapeutic agent continues to be controversial due to its psychoactive side effects and consequent legal status, however, leader of the team, Dr Wai Man Liu, explains: “It is important to stress that these cannabis-like substances are far removed from the cannabis that is smoked. These novel compounds have been specifically designed to be free of the psychoactive features, whilst maintaining anti-cancer action.” THC has previously been shown to attack cancer cells by interfering with important growth-processing pathways, however its mechanism of doing so has remained a mystery. Now, by using microarray technology – allowing them to simultaneously detect changes in more than 18,000 genes in cells


006 MEDLAB MAGAZINE ISSUE 1 2012


treated with THC – Dr Liu and his colleagues, have begun to uncover the existence of processes through which THC can kill cancer cells and potentially promote survival. The researchers hope that the findings will provide a crucial step towards the development of new therapies for many types of cancer. Dr Liu said: “Ultimately, understanding the fundamental mechanisms of these compounds will provide us with insights into developing new drugs that can be used to effectively treat cancers.”


in whole blood. The titer of HIV antibodies is also low in acute HIV infection before seroconversion, hence the increased possibility that oral


testing might miss more acute HIV infections than tests with blood specimens because of its lower sensitivity. Source: Labmedica


PROTEIN FAMILY HAILS HYPOXIA BREAKTHROUGH


THE DISCOVERY OF a new family of proteins which regulate the body’s hypoxic response has allowed a significant step forward in understanding the process which can cause and affect the progress of many diseases. The researchers – from Barts


Cancer Institute at Queen Mary, University of London, and the University of Nottingham – have uncovered a previously unknown level of hypoxic regulation at a molecular level in human cells. This may provide a novel pathway for the development of new drug therapeutics to fight disease, like cancer. “The results from this research


represent a significant advancement in our understanding of precisely how the hypoxic response works,” said Dr Tyson Sharp, a molecular oncologist from Nottingham’s School of Biomedical Sciences. “It will help researchers develop better drugs to fight cancer and also other human diseases that are caused by low levels of oxygen within our body, such as anaemia, myocardial infarction, stroke and peripheral arterial disease.” Researchers discovered that LIM domain


containing proteins, namely LIMD1, function as molecular scaffolds which bring together two key enzymes in the hypoxic response pathway – pyrol hydroxylases (PHD2) and von Hippel-Lindau (VHL) tumour suppressor. Both PHD2 and VHL are involved in down-regulating the master regulator protein which responds to changes in intracellular oxygen – hypoxia-inducible factors or HIF- 1. When the hypoxic response malfunctions, loss of LIMD1 breaks down the bridge created between HD2 and VHL, and this enables HIF1 to function out of control and contribute to cancer formation. Cancer cells have a faulty hypoxic response, and as the cells multiply they hijack the response to create their own rogue blood supply. This new blood supply allows the cancer to form large tumours, and to help the cancer spread to other parts of the body. The work – funded by the Biotechnology and Biological Science Research Council (BBSRC) – is published in Nature Cell Biology. Further research is now being conducted at Barts Cancer Institute.


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