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The study published in Jan. 23 issue of theis a thumps up for those interested towards personalized medicine, a small but important step.
A person’s genetic make-up seems to influence how he or she reacts to certain hypertension medications. The new study focused on the NPPA (atrial natriuretic precursor A) gene, which is involved in forming atrial natriuretic polypeptide, which acts as a diuretic.
n all, 38,462 people with hypertension underwent genotyping [genetic testing] and were randomly assigned to receive a diuretic (chlorthalidone) or one of the following three drugs: a(amlodipine); an (lisinopril); or an alpha-blocker (doxazosin).
people with hypertension and two different NPPA genotypes (known as NPPA G664A and NPPA T2238C) responded differently to different medications.
Scientists from the Lucile Packard Children’s Hospital and the Stanford University School of Medicine have identified a pattern of gene expression shared by a small group of patients who beat the odds and remained healthy for years without medication, after undergoing Organ transplant.
The findings made by Minnie Sarwal, MD, PhD, a pediatric nephrologist at Packard Children’s is a major advantage in organ transplantation treatment. Transplant recipients who share the same pattern of genes but are still on conventional medication may be able to reduce or eliminate their lifelong dependence on immunosuppressive drugs. The study may also help physicians determine how best to induce acceptance, or tolerance, of donor organs in all transplant patients, regardless of their gene expression profiles.
Although the anti-rejection medications, known as immunosuppressants, tamp down the immune system enough to permit lifesaving organ transplants, their benefits come at a price. They also quash the body’s natural response to dangerous invaders, such as bacteria and viruses, and to rogue cancer cells. Transplant physicians prescribing immunosuppressants to their patients walk a fine line between avoiding organ rejection and increasing the risk of infection and cancer
The researchers used microarray, or gene chip, technology to compare gene expression patterns in blood samples from 16 healthy volunteers with those from three groups of adult kidney transplant recipients from the United States, Canada and France
Filed under: biodefense, bioinformatics blog, cancer, clinical genomics, DNA, DNA diagnostics, gene expression, gene therapy, genetic medicine, genetics, Genomics, microaray blog, Pharmacogenomics, transgenomics | 24 Comments »
ChIP-sequencing (ChIPSeq) – a combination of chromatin immunoprecipitation and next-generation, or parallel, sequencing. The feat was performed “with a speed and precision that goes beyond what has been achieved with previous technologies,” commentsgeneticist Stanley Fields, in an accompanying essay in Science.
hIP is a well-established lab technique to identify those specific sites where proteins latch onto the DNA. Cells are treated with a chemical to fossilize the links between DNA and protein, the chromatin is then isolated, the DNA broken up, and the attached proteins immunoprecipitated. Finally, the DNA stuck to the protein can be released and analyzed. Until now, the most high-throughput application of this technique involved using microarrays containing thousands of gene spots able to identify binding sites for transcription factors and the like.
Next-Generation Sequencing Invades Microarray Turf By Kevin Davies June 14, 2007 | Two new papers unveil a new dimension to commercial next-generation sequencing applications – one that could potentiallypose a threat to more-established microarray technologies. Using theGenome Analyzer from Illumina/Solexa, two groups working independentlyhave been able to map the locations across the genome where a specific
DNA-binding protein latches onto the DNA.
ChIPSeq is a cost-effective alternative to microarray methods, with a significant upside. “Other ultrahigh-throughput sequencing platforms, such as the one from 454 LifeSciences, could also be used to assay ChIP products, but whatever sequencing platform is used, our results indicate that read numbercapacity and input ChIP DNA size are key parameters,” Johnson et al. writes.ChIPSeq might be an order of magnitude cheaper than microarray alternatives, with the eight flow cell lanes in theGenome Analyzer offering excellent design flexibility. Fewer materialsare required, and the method can be applied to any organism – it is not restricted to available gene arrays.
The advantages of ChIPSeq over ChIP-chip include the ability to interrogate the entire genome rather than just the genesrepresented on a microarray. (For example, Johnson et al. point out thata similar experiment using Affymetrix-style microarrays would requireroughly 1 billion features per array.) There is also the benefit of
sidestepping known hybridization complications with microarrayplatforms. “Perhaps most usefully,” writes Fields, “ChIPSeq canimmediately be applied to any of those [available] genomes, rather thanonly those for which microarrays are available.”
Filed under: bioinformatics blog, DNA, gene expression, genetic medicine, microaray blog, microarray, microarray business, microarray cost, microarray industry, microarray price, Next Generation of DNA and RNA Microarrays | 1 Comment »
The Secret of how to prevent bacteria from developing drug resistance has been revealed in a new study.Drugs called bisphosphonates, widely prescribed for bone loss has been found to help in preventing an enzyme that helps in conjugation of bacteria, by help of which it derives drug resistance.
Many highly-drug resistant bacteria rely on an enzyme, called DNA relaxase, to obtain and pass on their resistance genes. Relaxase plays a crucial role in conjugation as it is the gate keeper that starts and stops the movement of DNA between bacteria durig conjugation.
researchers at the University of North Carolina at Chapel Hill, have stopped the microbes’ ability to spread, among other advantageous mutations, resistance to antibiotics, by disabling the enzyme using molecules known as bisphosphonates
The study by Matthew Redinbo and his associates is published in this week’s Proceedings of the National Academy of Sciences USA
The antibiotic-resistant Escherichia coli bacteria that were trying to pass their genes along, actually died when their DNA relaxase was shielded thus preveinting the spread of drug resistant bacteria andpossibility of more mutations.
The news is will bring fresh hopes at a stage when drug–resistant strain of the bacteria Staphylococcus aureus infects over 1 million US hospital patients every year.
The average human gene consists of 3000 bases, but sizes vary greatly, with the largest known human gene being dystrophin at 2.4 million bases. Residing at Chromosome 4 it has long been of interest to the medical community because its the gene responsible for huntington’s disease, polycystic kidney disease, a form of muscular dystrophy and a variety of other inherited disorders. Chromosome 2 is noteworthy for being the second largest human chromosome, trailing only chromosome 1 in size. It is also home to the gene with the longest known, protein-coding sequence – a 280,000 base pair gene that codes for a muscle protein, called titin, which is 33,000 amino acids long.
Now reseacrhers at Emory university has developed a microarray based test to chek for mutations in this gene. The current test do not detect all types of mutation that affects 1 in 3500 males according to the university wesbite.
Mutations in the dystrophin such as point mutations in a sequence of DNA can result in mistakes in gene expression and nonfunctional proteins that causes Duchenne muscular dystrophy (DMD).
A detailed presentation of the advantages of the test is available at the Emory Genetics Testing website. The test offeredon the Nimblegen CGH array platform gains more prominance as the company is now being acquired by Roche who has plans to dominate the clinical microarray market with its products in genetics testing space
The emory university Genetics testing lab offers numerous other genetic tests
Filed under: clinical diagnostics, clinical microarray, DNA diagnostics, gene expression, genetic medicine, genetic testing, microarray blog, microarray for clinical diagnostics, Pharmacogenomics | 7 Comments »
considered by some to be the ‘living fossils’ of a time when life was based on RNA -Rribozymes have been used by researchers to prevent the spread of HIV in the body
The Medical Marketing International Group (MMI) scientists have used these ancient RNA catalysts to suppress key receptors that allow HIV to enter cells
HIV enters cells using the cellular receptors CCR5 or CXCR4 and previous work has shown that preventing the expression of these receptors using the Company’s proprietary ribozymes, which target the messenger RNA (‘mRNA’) that encodes these proteins, is highly effective at preventing HIV replication in vitro. The results announced today show that the ribozyme technology can effectively deliver the ribozyme and suppress expression of these receptors in an advanced in vivo model. Moreover, a single administration of the ribozymes was able to maintain suppression of the receptors for a significant period (>35 days so far), indicating that a pool of HIV-resistant cells could be established.