Comparing diagnostic tests: trials in people with discordant test results

Diagnostic tests are traditionally compared for accuracy against a gold standard but can also be compared prospectively in a trial. A conventional trial comparing two tests would randomize each participant to a testing strategy, but a more efficient alternative is to give both tests to all participants and follow up those with discordant results. Participants could be randomized before or after testing. The statistical analysis of such a trial has not previously been described. We investigated two estimates of the risk difference for a binary outcome: one based on analysing outcomes as if from a conventional trial and one combining estimates of different parameters in the manner of a decision analysis. We show that the trial estimate and decision analysis estimate are both unbiased and derive approximate formulae for their standard errors. By using the decision analysis estimate (but not the trial estimate), the same precision can be achieved by randomizing before testing as by randomizing after. To avoid destroying equipoise, and to allow consenting and randomizing to be carried out at the same visit, we recommend randomizing before testing. Giving both tests to all participants means fewer need to be recruited: in one example from the literature, the proposed design was nearly four times more efficient in this sense than a conventional trial design. Copyright © 2012 John Wiley & Sons, Ltd.     

The Effect of Green Tea Consumption on Prostate Cancer Risk and Progression: A Systematic Review

This systematic review aimed to assess the clinical benefits of green tea consumption on the progression and prevention of prostate cancer (PCa). A systematic search was performed across the following databases: PubMed, Excerpta Medica dataBASE, Database of Abstracts of Reviews of Effects, Current Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials. We included studies from database inception to September 2015. Studies must report on the effect of green tea consumption on PCa. The quality of observational studies was assessed using the Newcastle-Ottawa Scale (NOS), while randomized controlled trials (RCTs) were assessed for quality using the Jadad scale. A total of 15 articles were included, with 11 reporting on the effect of green tea consumption on PCa prevention, and four reporting on the effect of green tea on treatment. Mean NOS for observational studies was 7.4 (SD±1.3), with a range from 6 to 9, while all three RCTs scored 5 on the Jadad scale. Findings demonstrate that green tea appears to be an effective chemopreventive agent, particularly in those with high-grade prostate intraepithelial neoplasia. However, evidence of efficacy in the treatment of PCa is currently lacking. Given the limitations in current studies, more well-designed RCTs should be undertaken to determine if green tea indeed has a role in the prevention and treatment of PCa.     

Contraindications and side effects of commonly used medications in coronary CT angiography

For certain clinical applications, coronary CT angiography (CCTA) has become a useful tool for the noninvasive evaluation of coronary artery atherosclerosis. To optimize image quality in CCTA, medications are often given prior to scanning to slow the heart rate or distend the arteries. These medications have side effects and are contraindicated in certain patient populations. Metoprolol is the ß-blocker of choice in CCTA, and it has been shown to be effective in achieving the goal heart rate of less than 65 beats per minute for CCTA and in minimizing variability of heart rate. It is contraindicated in patients with hypotension or high degree AV block, and it must be used with caution in patients with asthma or obstructive pulmonary disease, patients with decompensated heart failure, and those with vasospastic or vasoocclusive disease. Diltiazem, the calcium channel blocker of choice in CCTA, is a reasonable alternative for heart control, particularly in patients with asthma or bronchospastic disease, and patients with orthotopic heart transplants that have been sympathetically denervated. Sublingual nitroglycerin is especially useful in order to dilate distal arteries to improve stenosis visibility. However, it is contraindicated in patients on erectile dysfunction medications and those with severe anemia. It must be used cautiously in patients with aortic stenosis or other preload-dependant cardiac pathologies.     

Serological Detection of Antibodies to Peste des Petits Ruminants Virus in Large Ruminants

Peste des petits ruminants (PPR) is an economically important disease of small ruminants with a rapidly expanding geographical distribution. Peste des petits ruminants virus may manifest in a variety of ways with disease ranging from acute to subclinical. We investigated the exposure of large ruminants to PPRV in areas where the virus is endemic in the small ruminant population by assessing the serological status of groups of animals. This study focused on the Punjab province of Pakistan as an area where the virus is endemic and where mixed farming practices occur enabling close interactions between small and large ruminant populations. An overall PPR seropositivity was detected in 10.0% of cattle and 14.16% of buffaloes. Following an assessment of serological profiles in large ruminants within different age groups, a maximum seroprevalence was observed in cattle (17.5%) and buffaloes (22.5%) over 2 years of age indicating the potential utility of sampling large ruminant populations for PPR serosurveillance. The large ruminants sampled between one and two years of age had similar levels of seropositivity within populations with 11.2% and 16.2% of animals being seropositive, respectively. Current PPR vaccination strategies do not enable the differentiation between infected and vaccinated small ruminants, and as such, the serological surveillance of sheep and goats is of little value. When considering eradication programmes for PPRV, this factor is of great significance. However, where large and small ruminants are farmed together, serological surveillance of large ruminants may provide a snapshot of virus infection within populations where mild disease is present or where small ruminants are regularly vaccinated.     

Atypical focal nodular hyperplasia of the liver

BACKGROUND:Focal nodular hyperplasia,a benign hepatic tumor,is usually asymptomatic.However,rarely the entity can cause symptoms,mandating intervention. METHOD:We present a case of focal nodular hyperplasia of the liver,which caused a considerable diagnostic dilemma due to its atypical presentation. RESULTS:A 29-year-old woman presented with a 15-year history of a progressively increasing mass in the right upper quadrant which was associated with pain and emesis. Examination showed a firm,mobile mass palpab...     

Measurement of hematological and biochemical studies on wild marine carnivorous fishes from Vellar estuary, southeast coast of India

Hematological parameters have been recognized as valuable tools for monitoring fish health. Hematological and serum biochemical parameters were studied and compared between four marine carnivorous fish. Statistical analysis revealed that differences in hematological parameters between marine carnivorous fish were significant (P < 0.01). The result revealed that hematological red blood cells (RBC)/white blood cells (WBC) ratio, mean corpuscular volume, and mean cell hemoglobin concentration were significantly correlated at the P < 0.05 level. The RBC/WBC level increased due to the decrease in WBC during the study. Serum biochemical parameters can be used for confirming the maturity and monitoring any changes in the quality of waters and related soils.