Monday, September 6, 2010
Saturday, September 4, 2010
Scientists discover how omega-3 fatty acids shut down inflammation and reverse diabetes
(Picture, courtsey : Cell) Omega-3 fatty acids (
-3 FAs), DHA and EPA, exert anti-inflammatory effects, but the mechanisms are poorly understood. Now the  researchers  show that the G protein-coupled receptor 120 (GPR120) functions as an 
-3 FA receptor/sensor. As per the claim by the researchers, stimulation of GPR120 with  
-3 FAs or a chemical agonist causes broad anti-inflammatory effects in monocytic RAW 264.7 cells and in primary intraperitoneal macrophages. All of these effects are abrogated by GPR120 knockdown. Since chronic macrophage-mediated tissue inflammation is a key mechanism for insulin resistance in obesity, researchers fed obese WT and GPR120 knockout mice a high-fat diet with or without  
-3 FA supplementation.
The  
-3 FA treatment inhibited inflammation and enhanced systemic insulin sensitivity in WT mice, but was without effect in GPR120 knockout mice. In conclusion, GPR120 is a functional  
-3 FA receptor/sensor and mediates potent insulin sensitizing and antidiabetic effects in vivo by repressing macrophage-induced tissue inflammation. ….....
Friday, September 3, 2010
Thursday, September 2, 2010
Study on current insect repellants confirms need for better insect repellants...
In continuation of update on  mosquito repellents developments and DEET
Now, Johns Hopkins scientists have discovered what it is in the bugs'  molecular makeup that enables citronellal (the aromatic liquid used in  lotions, sprays and candles) and DEET, to deter insects from landing and  feeding on you. A better understanding of these molecular-behavioral  links already is aiding the team's search for more effective repellants.  
Researchers claim that, three taste receptors on the insects' tongue and elsewhere are needed to  detect DEET. Citronellal detection is enabled by pore-like proteins  known as TRP (pronounced "trip") channels. When these molecular  receptors are activated by exposure to DEET or citronellal, they send  chemical messages to the insect brain, resulting in an aversion response.
"DEET has low potency and is not as long-lasting as desired, so finding the molecules in insects that detect repellents opens the door to identifying more effective repellents for combating insect-borne disease," says Craig Montell, Ph.D., a professor of biological chemistry and member of Johns Hopkins' Center for Sensory Biology.
As per the lead researcher, when a mosquito lands, it tastes your skin with its gustatory  receptors, before it bites. Researchers suggests that,  one of the  reasons DEET is relatively effective is that it causes avoidance  responses not only through the sense of smell but also through the sense  of taste.
The team filled feeding plates with high and low concentrations of  color-coded sugar water (red and blue dyes added to the sugar), allowing  the flies to feed at will and taking note of what they ate by the color  of their stomachs: red, blue or purple (a combination of red and blue).  Wild-type (normal) flies preferred the more sugary water to the less  sugary water in the absence of DEET. When various concentrations of DEET  were mixed in with the more sugary water, the flies preferred the less  sugary water, almost always avoiding the DEET-laced sugar water.Flies  that were genetically engineered to have abnormalities in three  different taste receptors showed no aversion to the DEET-infused sugar  water, indicating the receptors were necessary to detect DEET. 
"We found that the insects were exquisitely sensitive to even tiny concentrations of DEET through the sense of taste," Montell reports. "Levels of DEET as low as five hundredths of a percent reduced feeding behavior."
To add to the evidence that three taste receptors (Gr66a, Gr33a and  Gr32a) are required for DEET detection, the team attached recording  electrodes to tiny taste hairs (sensilla) on the fly tongue and measured  the taste-induced spikes of electrical activity resulting from nerve  cells responding to DEET. Consistent with the feeding studies,  DEET-induced activity was profoundly reduced in flies with abnormal or  mutated versions of Gr66a, Gr33a, and Gr32a. 
In the second study,  Montell and colleagues focused on the repellent citronellal. To measure  repulsion to the vapors it emits, they applied the botanical compound  to the inside bottom of one of the two connected test tubes, and  introduced about 100 flies into the tubes. After a while, the team  counted the flies in the two tubes. As expected, the flies avoided  citronellal. 
The researchers identified two distinct types of  cell surface channels that are required in olfactory neurons for  avoiding citronellal vapor. The channels let calcium and other small,  charged molecules into cells in response to citronellal. One type of  channel, called Or83b, was known to be required for avoiding DEET. The  second type is a TRP channel. 
The team tested flies with mutated  versions of 11 different insect TRP channels. The responses of 10 were  indistinguishable from wild-type flies. However, the repellent reaction  to citronellal was reduced greatly in flies lacking TRPA1. Loss of  either Or83b or TRPA1 resulted in avoidance of citronellal vapor.
The  team then "mosquito-ized" the fruit flies by putting into them the gene  that makes the mosquito TRP channel (TRPA1) and found that the mosquito  TRPA1 substituted for the fly TRPA1. Researchers found that the mosquito-version of TRPA1 was directly activated by citronellal. Montell's lab and others have tallied 28 TRP channels in mammals and 13  in flies, broadening understanding about how animals detect a broad  range of sensory stimuli, including smells and tastes. 
Hop this discovery now raises the possibility of using TRP channels to find better insect repellents. 
2 : http://download.cell.com/neuron/pdf/PIIS0896627310005441.pdf?intermediate=true
Wednesday, September 1, 2010
Naringenin (grape fruits) initiates increased fatty acid oxidation, inhibits vLDL production...
Naringenin is a flavonoid that is considered to have a bioactive  effect on human health as antioxidant, free radical scavenger,  anti-inflammatory, carbohydrate metabolism promoter, and immune system  modulator. It is the predominant flavanone in grapefruit. It  has been  shown to have an inhibitory effect on the human cytochrome P450 isoform  CYP1A2, which can change pharmacokinetics in a human (or orthologous)  host of several popular drugs in an adverse manner, even resulting in  carcinogens of otherwise harmless substances. Naringenin has also been  shown to reduce hepatitis C virus production by infected hepatocytes  (liver cells) in cell culture. This seem to be secondary to Naringenin  ability to inhibit the secretion of very-low-density lipoprotein by the  cells.It has been reported that Naringenin,  lowers the plasma and  hepatic cholesterol concentrations by suppressing HMG-CoA reductase and  ACAT in rats fed a high-cholesterol diet. 
Now interestingly, researchers from Hebrew University of Jerusalem and Massachusetts General Hospital (MGH)  report that naringenin activates a family of small proteins, called  nuclear receptors, causing the liver to break down fatty acids. In fact,  the compound seems to mimic the actions of other drugs, such as the  lipid-lowering Fenofibrate and the anti-diabetic Rosiglitazone, offering  the advantages of both. If the results of this study extend to human  patients, this dietary supplement could become a staple in the treatment  of hyperlipidemia, type-2 diabetes, and perhaps metabolic syndrome. 
The researchers demonstrated that the compound activates PPARα and PPARγ by dramatically increasing the levels of a co-activator peptide of both, called PGC1α. At the same time, naringenin bound directly to LXRα, blocking its activation. These effects culminated with increased fatty acid oxidation and the inhibition of vLDL ('bad cholesterol') production.
The researchers demonstrated that the compound activates PPARα and PPARγ by dramatically increasing the levels of a co-activator peptide of both, called PGC1α. At the same time, naringenin bound directly to LXRα, blocking its activation. These effects culminated with increased fatty acid oxidation and the inhibition of vLDL ('bad cholesterol') production.
Authors claim that, it is a process which is similar to the Atkins diet, without many of the side effects and the liver behaves as if fasting, breaking down fatty acids instead of carbohydrates."It is a fascinating find," says Yaakov Nahmias, PhD, of the Hebrew University of Jerusalem the paper's senior author. "We show the mechanism by which naringenin increases two important pharmaceutical targets, PPARα and PPARγ, while blocking a third, LXRα. The results are similar to those induced by long periods of fasting".
"Dual PPARα and PPARγ agonists, like naringenin, were long sought after by the pharmaceutical industry," says Nahmias, "but their development was plagued by safety concerns. Remarkably, naringenin is a dietary supplement with a clear safety record. Evidence suggests it might actually protect the liver from damage."....Ref : http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0012399
Monday, August 30, 2010
Plantain and broccoli fiber help in Crohn’s disease........
New research from University School of Clinical Sciences in Liverpool, lead by Prof. Jonathan Rhodes,  suggests that plant fibers in plantains and broccoli can help prevent relapses of Crohn's disease.  This disease is a long term disease of the gut that is characterized by  inflammation of the lining of the digestive system, with symptoms  including diarrhea and abdominal pain. Scientists believe that rise in processed food and decrease in fibers in  diet could be a reason for rise of incidence of this disease.
For this study the scientists tested a range of soluble plant fiber to judge their effect on Crohn's disease.  Soluble plant fiber is the kind which comes out of vegetables when they  are boiled in water. The results of the study showed that soluble fiber  from plantain and broccoli specifically stopped 45% to 82% of the  bacteria E.coli from crossing into cells in the intestine. Fiber from leek and apple had no effect. 
The sticky E. coli are capable of penetrating the gut wall via  special cells, called M-cells that act as 'gatekeepers' to the lymphatic  system. Studies have shown that patients with Crohn's disease  this leak leads to chronic inflammation in the gut. This study shed  that plantain soluble fibers prevented the uptake and transport of E. coli  across M.cells. They compared these results with tests on  polysorbate-80 - a fat emulsifier used in processed food to bind  ingredients together. The tests revealed that polysorbate had the  opposite effect to plantain fibers, and encouraged the movement of  bacteria through the cells. 
The research shows that different dietary components can have powerful  effects on the movement of bacteria through the bowel. We  know  the general health benefits of eating plantain and broccoli,  which are both high in vitamins and minerals, but until now we have not  understood how they can boost the body's natural defences against  infection common in Crohn's patients. This work, suggests that it might be  important for patients with this condition to eat healthily and limit  their intake of processed foods.
Experimental drug PLX4032 holds promise against cancers with faulty BRAF gene....
Plexxikon  recently announced the publication  of data from the Phase 1 clinical trial of PLX4032 (RG7204), confirming  that treatment of metastatic melanoma patients with the BRAF V600E  (mutation resulted in significant tumor shrinkage in the majority of  patients). The company claims that, in the melanoma extension cohort of the study,  nearly all patients showed some response; 81 percent of patients had  tumor shrinkage of at least 30 percent and the company concludes that these results further  support the current PLX4032 development strategy, which includes  parallel and ongoing Phase 2 (BRIM2) and Phase 3 (BRIM3) studies to  support registration. PLX4032 is a novel, orally administered, targeted  agent that is selective for a key oncogenic driver in melanoma and other  cancers. 
Primary objectives of the melanoma extension cohort were to establish  further safety and pharmacokinetics (PK) data beyond the dose-escalation  phase, as well as demonstrate proof-of-concept in the target patient  population at the MTD of 960 mg twice daily.
Results Demonstrate Significant Anti-tumor Activity with PLX4032 . In the melanoma extension cohort, in which 32 patients  with metastatic melanoma harboring the BRAF mutation were enrolled, data  showed an 81 percent response rate by RECIST criteria, including:  2 complete responses (no evidence of disease) and 24 partial responses (tumor shrinkage of at least 30 percent)
As per the claim by the company, all patients except two showed some tumor regression. The estimated  median progression-free survival (PFS) among these patients was at least  seven months as of January 31, 2010, compared to historical PFS of less  than two months. Sixteen patients were still on study as of January 31,  2010.
Company also claims that, drug-related adverse events were predominantly mild in severity and  included rash, joint pain, photosensitivity and fatigue. Among the 48  patients treated in the dose-escalation and extension cohorts, 18  patients developed cutaneous squamous cell carcinoma in sun exposed  areas of the skin (primarily keratoacanthoma subtype) that were treated  by excision, while treatment with PLX4032 was continued. 
This PLX4032 trial represents the first evidence that a treatment that targets activating BRAF mutations can induce significant tumor regressions in patients," said Dr. K. Peter Hirth, CEO of Plexxikon. He adds that "these data are particularly encouraging, with responses observed at all sites of disease, including challenging visceral lesions in the bone, liver and small bowel and they are hopeful that PLX4032 will provide similar benefit to these patients so urgently in need of effective therapies."..
PLX4032 is currently being tested in a randomized, controlled Phase 3  (BRIM3) trial in previously untreated metastatic melanoma patients who  test positive for the BRAF mutation. Enrollment for the trial is  currently under way. The primary endpoint for the BRIM3 trial is overall  survival....
Ref : http://www.nejm.org/doi/full/10.1056/NEJMoa1002011
Labels:
Metastatic Melanoma,
PLX4032,
skin cancers.
Saturday, August 28, 2010
Thursday, August 26, 2010
FDA approves Chelsea Therapeutics' Phase II protocol for CH-4051 antifolate in rheumatoid arthritis
Chelsea Therapeutics International, Ltd. announced the   confirmation by the U.S. FDA,  that its  proposed Phase II protocol for CH-4051  in rheumatoid arthritis has been approved by the agency. Chelsea plans to initiate patient screening next month and initiating treatment in October.
This multi-national, double-blind, randomized Phase II trial of CH-4051,  an orally available metabolically stable antifolate, is intended to  evaluate the safety and efficacy of CH-4051 in a 250-patient head-to-head study against methotrexate (MTX). Patients with rheumatoid arthritis  who are experiencing an inadequate response to MTX treatment will be  randomized to receive daily oral doses of 0.3 mg, 1.0 mg, 3.0 mg or 3.0  mg plus folate of CH-4051 or 20 mg weekly dose of MTX plus folate  supplement for 12 weeks following a two-week MTX-washout. The primary efficacy analysis will be conducted using the hybrid American College of Rheumatology,  or ACR, score (hACR), which allows for a more comprehensive assessment  of treatment benefit across all seven symptomatic and functional  components of the standard ACR 20/50/70 evaluations historically used in  RA trials. 
"Although MTX is considered the standard of care in RA, both as a monotherapy and in combination with other RA treatments, the dosing and maximal therapeutic benefit of MTX is limited by well-documented tolerability issues, long-term safety concerns and variable bioavailability," commented Dr. Simon Pedder, president and CEO of Chelsea Therapeutics. "Given that CH-4051 is metabolically stable and that all of our preclinical and clinical work suggests enhanced absorption, dramatically increased potency and improved tolerability over MTX, we believe CH-4051 will be safe and highly efficacious in a historically treatment-resistant patient population."
Chelsea intends to conduct an un-blinded interim efficacy  analysis after approximately 50% of patients in the two lower CH-4051  dose groups complete treatment and expect to report results from this  analysis in the third quarter of 2011. Full study results, inclusive of  all dose groups, are expected in mid-2012. 
As previously reported, results from Chelsea's Phase I single and  multiple ascending dose studies demonstrated that CH-4051 was well  tolerated at doses up to and including 7.5mg, a dose range likely to be  effective for multiple autoimmune disorders. The 5mg dose was as well  tolerated as placebo. No serious adverse events occurred during the  study and pharmacokinetic data indicated dose proportionate increases in  plasma levels of CH-4051. Furthermore, it was revealed that plasma  concentrations in the study were comparable to those seen in animal  pharmacology studies in which CH-4051 demonstrated superior suppression  of RA than both the maximally tolerated dose of methotrexate and  equivalent doses of CH-1504 (see structure)....
Wednesday, August 25, 2010
New compound may be effective against Chagas' disease
New compound may be effective against Chagas' disease
Ref : http://www.asm.org/images/Communications/chagas%20-%20aac.pdf
Ref : http://www.asm.org/images/Communications/chagas%20-%20aac.pdf
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