Thursday, February 23, 2017
Wednesday, February 22, 2017
Ref : http://cancerpreventionresearch.aacrjournals.org/content/early/2016/04/30/1940-6207.CAPR-15-0290
Posted by dr.umesh l at 6:35 AM
Tuesday, February 21, 2017
A team led by Rice University scientists has improved the production of a potent anti-tumor antibiotic known as uncialamycin.
The Rice lab of synthetic chemist K.C. Nicolaou announced this month it had streamlined the total synthesis of uncialamycin to make it simpler to create novel variations of the molecule. Such variations could allow the substance, which is too toxic in its original form, to be made into useful drugs to fight cancer.
The new work by Nicolaou and colleagues appears in the Journal of the American Chemical Society.
Nicolaou's lab specializes in the synthesis of molecules found in nature with medicinal properties, but in amounts too small for testing or clinical use. The new process is scalable for bulk production, he said.
Uncialamycin is an enediyne, compounds defined by the presence of nine- and 10-member atomic rings in their structures. Two other enediynes, neocarzinostatin and calicheamicin, are or have been used as chemotherapy agents to treat leukemia and cancers of the liver and the brain.
"The 10-member ring is like the warhead of the molecule," Nicolaou said. "The ring undergoes the Bergman reaction, producing radicals that cut both strands of the DNA, rendering it difficult to repair by the cell. It's a Trojan horse that gets inside the cell and causes havoc."
The payoff has been a long time coming for Nicolaou and his colleagues who began investigating uncialamycin after it was isolated from a strain of streptomycete related to Streptomyces cyanogenus, a marine bacterium, in 2005. The lab reported the total synthesis of the molecule in 2007 and followed up in 2008 with a report on new synthetic versions and demonstration of its DNA-cleaving, antibiotic and cytotoxic capabilities.
He said the newly developed synthetic strategies and methods make it possible to synthesize a series of designed analogs of the molecule for biological evaluation. As part of the new study, the lab synthesized not only pure synthetic uncialamycin but also 13 variants of the molecule, with handles for attachment to cancer-cell-associated antibodies and other drug-delivery systems.
These were tested for their potency against lung, gastric, ovarian and multidrug-resistant cancer cell lines. Three of the variants showed "remarkably high potency against the tested cell lines," the researchers reported.
Nicolaou said the analogs proved stable enough to be used as payloads in antibody drug conjugates that combine a delivery system - an antibody capable of recognizing and targeting cancer cells - with the anti-cancer drug through a chemical linker that joins the two until they reach the target.
Ref : http://pubs.acs.org/doi/abs/10.1021/jacs.6b04339
Monday, February 20, 2017
In continuation of my update on paclitaxel
New research indicates that paclitaxel, which is the most commonly used chemotherapy for breast cancer, suppresses tumors when given at a certain dosage, but at low doses, it actually promotes cancer spread to the liver.
The findings suggest that lowering the dose of paclitaxel to reduce toxic side-effects is not a safe strategy.
"Paclitaxel and its analogous compounds are the first line agents widely used in clinical cancer chemotherapy. However, potential risks and reasonable treatment strategies of paclitaxel continue to be widely investigated," wrote the authors of The FEBS Journalstudy.
Friday, February 17, 2017
A recent meta-analysis in Scientific Reports supports a link between EPA and DHA omega-3 intake and a reduced risk of death by any cause. The meta-analysis included 11 studies involving 371,965 participants and 31,185 death events, with a subset of the studies being used for different analyses.
In the analysis of n-3 LCPUFA intake, there was a 9% reduced risk of all-cause death associated with high versus low omega-3 intake. In the dose-response analysis, an increase in EPA/DHA intake of 300 mg/day was associated with a 6% lower risk of all-cause mortality. These findings suggest that both dietary and circulating n-3 LCPUFA are shown to be significantly associated with reduced risk of all-cause mortality.
According to study author Manfred Eggersdorfer, "The meta-analysis of 11 prospective observational studies demonstrates that each 1% increment of omega-3s in total fatty acids in blood may be associated with a 20% decrease in risk of all-cause mortality. This is an important finding for the potential contribution of adequate omega-3 intake to public health."
Thursday, February 16, 2017
Wednesday, February 15, 2017
"Phenolic compounds have good antioxidant activity, and there is increasing evidence that this antioxidant activity affects biochemical pathways affiliated with inflammation in mammals. We need inflammation because it's a response to disease or damage, but it's also associated with initiation of a number of degenerative diseases. People whose diets consist of a certain level of these compounds will have a lesser risk of contracting these diseases," explains U of I geneticist Jack Juvik.
"It's going to take awhile," Juvik notes. "This work is a step in that direction, but is not the final answer. We plan to take the candidate genes we identified here and use them in a breeding program to improve the health benefits of these vegetables. Meanwhile, we'll have to make sure yield, appearance, and taste are maintained as well."
"These are things we can't make ourselves, so we have to get them from our diets," Juvik says. "The compounds don't stick around forever, so we need to eat broccoli or some other Brassica vegetable every three or four days to lower the risk of cancers and other degenerative diseases."
Tuesday, February 14, 2017
Monday, February 13, 2017
In continuation of my update fentanyl
The recent overdose death of rock legend Prince has brought renewed focus on the dangers posed by synthetic opioids -- laboratory-created narcotics tweaked by chemists to produce potentially lethal highs while skirting U.S. drug laws.
Prince Rogers Nelson, 57, died April 21 from an overdose of fentanyl, a drug often used to quell pain in cancer patients when traditional opioids prove ineffective.
Despite its legitimate medical uses, fentanyl has acquired a growing reputation as a dangerous street drug thanks to at least a dozen synthetic variants now available to users, according to the U.S. Drug Enforcement Administration (DEA).
And fentanyl is only one of numerous synthetic opioids and designer drugs now flooding the illicit drug market in the United States, DEA acting chief Chuck Rosenberg warned during a U.S. Senate hearing last week.
"We are trying to keep up with a picture that changes almost every day," Rosenberg testified. "We've identified something like 400 new psychoactive substances over the last four or five years."
Another synthetic opioid, U-47700, has been connected to at least 50 deaths nationwide, but is so new to the black market that the DEA has not yet moved to control it, according to the Associated Press.
Synthetic narcotics are dangerous because their potency can far outstrip traditional opioids. For example, fentanyl is 25 to 40 times more potent than heroin, and 50 to 100 times more potent than morphine, said Dr. Mitra Ahadpour. She is a medical officer with the Center for Substance Abuse Treatment in the U.S. Substance Abuse and Mental Health Services Administration.
Rosenberg testified that "fentanyl is so dangerous we've had to instruct our agents that if they touch it or inhale it accidentally, they can die."
Several states reported sharp increases in overdose deaths caused by fentanyl and its analogs in 2014, a health advisory from the U.S. Centers for Disease Control and Prevention noted. Ohio reported 514 fentanyl-related deaths in 2014 compared to 92 in 2013, while Maryland had 185 fentanyl deaths in 2014 compared to 58 the year before.
Ahadpour explained that "if someone is not opioid-tolerant, and uses either pharmaceutical or illicit fentanyl, you have a very high increased chance of respiratory depression and dying. Their breathing slows down, it goes to shallow breathing, and then they stop breathing."
There's wide variation in the potency of these synthetic drugs, and often they are cut with other illicit drugs, Ahadpour added. A user might buy heroin not knowing that it has been cut with fentanyl to increase its potency.
Eleanor Artigiani, deputy director of policy and governmental affairs with the University of Maryland's Center for Substance Abuse Research, said, "They may think they're getting heroin, or they're just buying a Xanax pill off the street, when it's actually one of these other substances."
Artigiani added, "From what I've been hearing recently, sometimes even the people selling these drugs don't know exactly what's in them either. It's like Russian roulette, because you don't really know what you're getting or what effect it's going to have on you."
Toxicology tests concluded that Prince died from a fentanyl overdose, although the medical examiner's report did not say whether the fentanyl was prescription or an illicit analog, CNN reported.
Designer drugs are typically based on medications that have been around for decades, Artigiani said.
Fentanyl was first created in Belgium in the late 1950s, the DEA says, while U-47700 was developed in the 1970s by the pharmaceutical company Upjohn as a potential alternative for morphine.
Black market drug makers come across the formula for a drug, and then tweak the molecule slightly so that it has the same effect on people but isn't technically the same substance, Artigiani explained.
"There's a journal article or a patent document or something that gets produced," she said. "Illicit chemists find it and reproduce it or tweak the molecules to look for other kinds of things that aren't illegal, that haven't been scheduled yet."
Other synthetic opioids on the streets include substances with names like W-18, AH-7921 and MT-45, according to Congressional testimony provided by James Hall, an epidemiologist with the Center for Applied Research on Substance Use and Health Disparities at Nova Southeastern University in Miami.
Illicit drug manufacturers also produce other categories of designer drugs besides synthetic opioids, Hall said, including synthetic versions of cannabinoids, stimulants and hallucinogens.
Nearly all synthetic opioids and other designer drugs are manufactured in China, U.S. National Drug Control Policy Director Michael Botticelli testified before the Senate.
The designer drugs enter the United States either through the mail or across the Mexican or Canadian border, he said, and often are sold at head shops and other retail stores.
State and federal lawmakers are reviewing legislation designed to improve response against new synthetic narcotics, Botticelli said, and the United States is leading discussions with international partners to improve the global response to these drugs.
But right now, law enforcement often is several steps behind the traffickers because U.S. laws aren't flexible enough to quickly outlaw emerging drug analogs, Rosenberg told Congress.
"I almost feel each time I sign an administrative control regulation that I'm simply telling the bad guys, 'Not this one any more. Move over here.' And that's what they do," Rosenberg said. "For every one substance we've controlled, legislatively or administratively, there are 11 more out there that are uncontrolled."
Friday, February 10, 2017
FDA Approves Rayaldee (calcifediol) to Treat Secondary Hyperparathyroidism in Patients with Chronic Kidney Disease
OPKO Health, Inc. announced that the U.S. Food and Drug Administration (FDA) has approved Rayaldee (calcifediol) extended release capsules for the treatment of secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 chronic kidney disease (CKD) and serum total 25-hydroxyvitamin D levels less than 30 ng/mL. Rayaldee is a patented extended release product containing 30 mcg of a prohormone called calcifediol (25-hydroxyvitamin D3).
"FDA's approval of Rayaldee represents an important milestone for OPKO," noted Dr. Phillip Frost, CEO and Chairman of OPKO. "Rayaldee is the first product to receive FDA approval for this important indication and is one of OPKO's many pharmaceutical products being developed for significant medical problems which will benefit from new treatment options."
Results from two 26 week placebo controlled, double blind phase 3 trials demonstrated that a larger proportion of stage 3 or 4 CKD patients with SHPT and vitamin D insufficiency achieved ≥30% reductions in plasma intact parathyroid hormone (iPTH) when treated with Rayaldee than with placebo. Vitamin D insufficiency was corrected in more than 80% of the patients receiving Rayaldee compared with less than 7% of subjects receiving placebo. Mean serum calcium and phosphorus levels increased by 0.1 mg/dL during Rayaldee treatment compared to placebo treatment, but these changes were deemed clinically irrelevant. No differences in Rayaldee's efficacy or safety were observed between patients with stage 3 CKD or stage 4 CKD.
"Rayaldee fills a large void in the current treatment options for SHPT in predialysis patients," commented Dr. Charles W. Bishop, CEO of OPKO's Renal Division. "The current standard of care is high dose vitamin D supplementation, an approach for treating SHPT that is neither FDA approved nor demonstrated to be safe and effective in this population. SHPT is a progressive disease that becomes increasingly debilitating and difficult to treat, necessitating timely and effective treatment."
"Rayaldee is an important new option for treating SHPT in patients with stage 3 or 4 CKD and vitamin D insufficiency," stated Kevin J. Martin, Director of Research, Division of Nephrology at Saint Louis University School of Medicine. "The great majority of SHPT cases in this patient population are associated with vitamin D insufficiency, a problem that Rayaldee can correct."
Rayaldee (calcifediol) extended release capsules are approved by the U.S. Food and Drug Administration (FDA) for the treatment of SHPT in adult patients with stage 3 or 4 CKD and serum total 25-hydroxyvitamin D levels less than 30 ng/mL. Rayaldee has a patented formulation designed to raise serum total 25-hydroxyvitamin D (prohormone) concentrations to targeted levels (at least 30 ng/mL) and to reduce elevated iPTH. OPKO expects to launch Rayaldee in the U.S. through its dedicated renal sales force in the second half of 2016. Rayaldee is not indicated in patients with stage 5 chronic kidney disease or end-stage renal disease on dialysis. The full prescribing information for Rayaldee will be available at www.opkorenal.com.
Potential side effects of Rayaldee include hypercalcemia (elevated serum calcium), which can also lead to digitalis toxicity, and adynamic bone disease with subsequent increased risk of fractures if intact PTH levels are suppressed by Rayaldee to abnormally low levels. Severe hypercalcemia may require emergency attention; symptoms of hypercalcemia may include feeling tired, difficulty thinking clearly, loss of appetite, nausea, vomiting, constipation, increased thirst, increased urination, and weight loss. Digitalis toxicity can be potentiated by hypercalcemia of any cause. Excessive administration of Rayaldee can cause hypercalciuria, hypercalcemia, hyperphosphatemia, or oversuppression of intact PTH. Common symptoms of vitamin D overdosage may include constipation, decreased appetite, dehydration, fatigue, irritability, muscle weakness, or vomiting. Patients concomitantly taking cytochrome P450 inhibitors, thiazides, cholestyramine, phenobarbital or other anticonvulsants may require dose adjustments and more frequent monitoring.
The most common adverse reactions in clinical trials (≥3% and more frequent than placebo) were anemia, nasopharyngitis, increased blood creatinine, dyspnea, cough, congestive heart failure and constipation.