Archive | July, 2011

Diabetes Mellitus is Associated With Increased Prostate Tumor Risk

Even though previous studies have suggested that men with diabetes mellitus (DM) have a lower risk of prostate cancer, Duke University researchers now report that their findings suggest that there is a relationship between DM and increased risk of aggressive prostate tumors.

Leah Gerber, MSc, and colleagues at the Duke University Prostate Center retrospectively analyzed statistical data from 1,848 men from the center’s database who underwent radical prostatectomy for prostate cancer at Duke University Medical Center between 1999 and 2009 and who had complete clinical information.  The number of patients with DM at time of surgery was 197 or 10.7% of men in the study.

After the researchers adjusted for demographic and clinical covariates, they found that men with preexisting DM had almost 50% increased risk of aggressive prostate cancer compared to men without DM.  Race and obesity did not appear to have an effect on this association.  These findings could partly explain why meta-analyses show that pre-existing DM is a significant risk factor for prostate cancer and overall mortality.  Gerber reports that if the findings hold in other populations, then the finding can be used to stratify patients by risk and identify therapeutic agents acting within the molecular pathways by both disease processes.  Additionally, the team reported that investigating pharmacological agents used to treat DM should continue to determine a potential benefit against prostate cancer.

The study data was presented at the 2011 annual meeting of the American Urological Association and funded by the Duke Division of Urologic Surgery.

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Tests for Overactive Bladder Drugs Produce Mixed Results

A randomized placebo-controlled trial showed that overactive bladder (OAB) symptoms decreased significantly within four weeks after the start of treatment with the investigational beta-3 agonist mirabegron.  Frequency of urinary incontinence and urination decreased significantly with two different doses of mirabegron.

This improvement in symptoms was correlated with improvement in patient-reported outcomes, including treatment satisfaction, symptoms, and quality of life.

According to presentations at the American Urological Association meeting adverse events occurred at similar rates in the placebo-controlled and mirabegron-treated patients.

Mirabegron is a first-in-class agent developed specifically for the treatment of OAB that has not been approved by the FDA.  It selectively binds and activates beta-3 adrenoreceptors on bladder detrusor muscle to facilitate filling and storage.

Favorable results from phase II studies of mirabegron led to this phase III, randomized and placebo-controlled study involving more than 1,300 patients with OAB.  Investigators at 132 sites throughout the United States and Canada randomized the patients to receive either the placebo or 50-mg or 100-mg of mirabegron.  Researchers examined patient diaries recording changes in the number of daily episodes of urinary incontinence and urination from baseline to 12 weeks.

About three-fourths of study participants were women with a mean age of 60.  About four in ten patients had mixed stress/urgency incontinence with urgency predominance, a third had no incontinence, and the remainder had urgency incontinence.

The number of incontinence episodes per 24 hours had declined in all three treatment groups after 12 weeks, but there were more significant reduction in the 50-mg and 100-mg mirabegron treatment groups.  The incidence and severity of adverse events including hypertension, urinary tract infection, headache and nasopharyngitis were similar across the three groups.  Patient-reported outcomes were all significantly better in the mirabegron treatment groups compared with the placebo-controlled group.

In contrast to these mirabegron results, findings from a randomized trial of ONO-8359, a prostaglandin EP1 receptor antagonist, showed no significant improvement in any of its treatment groups.   The study involved 435 patients randomized to a placebo, tolterodine, or one of three doses of ONO-8539.  In this study, patients were randomized on the basis of findings from a three-day placebo run-in that showed at least eight micturitions per 24-hour period, at least one urgency episode per 24 hours, and at least six urgency episodes during the three-day run-in.  Researcher compared the number of urinations per 24 hours at baseline to 12 weeks.    They found no significant differences between any dose of ONO-8358 and placebo for any of the outcomes.

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Johns Hopkins Students Create Device to Improve Kidney Dialysis Process

Bioengineering graduate students at Johns Hopkins University have invented a device that can reduce the risk of infection, clotting, and narrowing of the blood vessels in kidney dialysis patients.

The students discovered the need for such a device last year when they accompanied physicians on hospital rounds as part of their program.  One doctor had to perform a procedure to open a narrowed blood vessel at a kidney patient’s dialysis access site.  The students found out that this narrowing was a common problem among kidney dialysis patients.

These students learned that 350,000 people in the United States and 1.5 million people worldwide experience kidney failure that requires them to undergo hemodialysis to prevent a fatal buildup of toxins in the bloodstream.  They found out that the three most common ways to connect the machine to the patient’s bloodstream only work for a short time because of problems with infection, blood clots and narrowing of the blood vessels.  The students found these current options to be “grossly inadequate” and lead to increased healthcare expenses and sometimes patient deaths.

While the device, the Hemova Port, has not been tested in human patients, it has been used in tests on animals.  The prototype is designed to be implanted under the skin of a patient’s leg, giving technicians easy access to the patient’s bloodstream and reducing the risk of infection and clotting.  The device’s two valves can be easily opened and closed at the beginning and end of a dialysis procedure with a technician’s syringe from outside the skin.  Furthermore, the devise includes a simple cleaning system, which helps prevent infections.

The students’ device won them a $10,000 first prize in the 2011 American Society of Mechanical Engineers (ASME) showcase.  The five biomedical engineering students on the team were enrolled in a one-year master’s degree program at Johns Hopkins University’s Center for Bioengineering Innovation and Design.  Sherri Hall, Peter Li, Shishira Nagesh, Mary O’Grady and Thora Thorgilsdottir all recently graduated, but Li, along with Brandon Doan, has remained in Baltimore to form a company that will continue to test and develop the project.  The other four team members will serve as consultants for the project.  The team has filed for three provisional patents covering their device and applied for grants for further testing.

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Relationship Between Kidney Cancer and Arsenic Found

A new study in the Journal of Urology finds that people with moderately elevated levels of arsenic in their urine may have an increased risk of kidney cancer, especially if they have high blood pressure and kidney disease.  This does not necessarily mean that arsenic leads to kidney cancers.  Researchers report that one possibility is that kidney cancer leads to higher levels of arsenic in the urine.

While high levels of arsenic have been linked to many forms of cancer and some studies have linked moderately elevated levels of arsenic to high blood pressure and type 2 diabetes, the effects of low-level arsenic exposure are not yet fully known.

This new study was conducted in Taipei, Taiwan, where researchers looked at the arsenic levels in the urine of people who live in an area with low arsenic concentrations in the drinking water.  In Taipei, arsenic levels in tap water ranges from undetectable to 4 micrograms per liter, which is below the 10 micrograms per liter allowed by the U.S. Environmental Protection Agency (EPA).  Researchers compared 132 patients with kidney cancer to 260 cancer-free adults of the same age and sex.

In general, there was a relationship between higher arsenic levels in the urine and higher chances of kidney cancer.  This relationship was strongest for people who had high blood pressure or impaired kidney function, which have been established as risk factors for kidney cancer.  Study participants with both of these conditions and relatively high levels of arsenic in their urine were six times more likely than people with none of these risk factors to contract kidney cancer.  Participants with two of these risk factors had a quadruple rate of increase in risk of kidney cancer.

One possibility proposed by both researchers involved with the study and researcher who were not was that arsenic exposure led to high blood pressure or kidney disease in some people, which, in turn, contributed to their kidney cancer.

An estimated 13 million Americans live in areas where the public water supply exceeds the EPA’s limit of 10 micrograms per liter, and water from unregulated private wells may contain too much arsenic.

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