Measurement of bisphenol A levels in human urine.
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We report a new approach for assessing human exposure to bisphenol A (BPA) by measuring BPA in urine after enzymatic deglucuronidation. This method involves addition of (13)C(12)-labeled BPA, enzymatic deconjugation, solid-phase extraction, and derivatization with pentafluorobenzyl bromide. The product of the derivatization is separated by gas chromatography followed by mass spectrometric detection using negative chemical ionization and selected ion monitoring. Using this analysis method, urine samples fortified with both a constant level of labeled BPA and a range of unlabeled BPA levels (0.27-10.6 ng/ml) demonstrated constant percentage recovery. In addition, a range of urine sample volumes (0.25-10.0 ml) with constant amounts of added internal standard produced a linear response (r(2)=0.99). The method limit of detection was 0.12 ng/ml. This method was validated by duplicate analyses using gas chromatography coupled to a high-resolution mass spectrometer. (+info)
Safety of the insect repellent N,N-diethyl-M-toluamide (DEET) in pregnancy.
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The safety of daily application of N, N-diethyl-m-toluamide (DEET) (1.7 g of DEET/day) in the second and third trimesters of pregnancy was assessed as part of a double-blind, randomized, therapeutic trial of insect repellents for the prevention of malaria in pregnancy (n = 897). No adverse neurologic, gastrointestinal, or dermatologic effects were observed for women who applied a median total dose of 214.2 g of DEET per pregnancy (range = 0-345.1 g). DEET crossed the placenta and was detected in 8% (95% confidence interval = 2.6-18.2) of cord blood samples from a randomly selected subgroup of DEET users (n = 50). No adverse effects on survival, growth, or development at birth, or at one year, were found. This is the first study to document the safety of DEET applied regularly in the second and third trimesters of pregnancy. The results suggest that the risk of DEET accumulating in the fetus is low and that DEET is safe to use in later pregnancy. (+info)
Five ruminally cannulated Holstein steers (176 kg) were used in a 5 x 5 Latin square to evaluate the effects of branched-chain AA supplementation on N retention and plasma AA concentrations of steers. Steers were limit-fed (3.0 kg/d of DM) twice daily diets low in ruminally undegradable protein (72% soybean hulls, 19% alfalfa, 5% molasses, and 4% vitamins and minerals). Acetate (400 g/d) was continuously infused into the rumen. Treatments were continuous abomasal infusions of 1) 115 g/d of a mixture of 10 essential AA designed to exceed the steers' requirements (10AA), 2) 10AA with Leu removed, 3) 10AA with Ile removed, 4) 10AA with Val removed, and 5) 10AA with all three branched-chain AA removed. Experimental periods were 7 d, with 3 d for adaptation to treatments and 4 d for total fecal and urinary collections for N balance. Blood samples were collected 5 h after feeding on d 7. Retained N decreased in response to removal of Leu (P < 0.06), Val (P < 0.05), or all three branched-chain AA (P < 0.05). Plasma Leu concentrations decreased (P < 0.05) in response to removal of Leu and all three branched-chain AA. Plasma Ile concentrations decreased (P < 0.05) in response to removal of Ile and all three branched-chain AA but increased (P < 0.05) in response to removal of Leu. Plasma Val concentrations decreased (P < 0.05) in response to removal of Val and all three branched-chain AA but increased (P < 0.05) in response to removal of Leu. Responses in N balance and plasma AA concentrations of growing cattle limit-fed soybean hull-based diets demonstrate limitations in the basal supply of Leu and Val but not Ile provided that supplies of all other essential AA are met. (+info)
Yield and cost of individual common diagnostic tests in new primary care outpatients in Japan.
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BACKGROUND: Appropriate diagnostic testing involves considerations of cost-effectiveness. We examined the cost-effectiveness of individual tests in a panel of tests defined by the Japan Society of Clinical Pathology. METHODS: We studied 540 new, symptomatic primary care outpatients with a set of 30 common diagnostic tests [the Essential Laboratory Tests (2); ELT(2) panel] for clinical evaluation and identification of occult disease. A useful result (UR) of testing was defined as a finding that contributed to a change in a physician's diagnosis or decision-making relating to a "tentative initial diagnosis" obtained from history and physical examination alone. RESULTS: The ELT(2) panel testing yielded 398 URs and uncovered 261 occult diseases among 540 patients. In total, 1592 tests contributed to either UR-generation or discovery of occult disease. The cost per effective test (cost required per test that contributed to either definition of effectiveness) ranged from 108 yen (approximately 0.92 US dollars) for total cholesterol to 6200 yen (approximately 52.50 dollars) for chest x-ray. Contribution rates and the cost per effective test varied among disease categories. We restructured panel components considering the effectiveness of each test. Subsets of the ELT(2) would have improved cost-effectiveness and achieved cost savings in five of eight disease categories. CONCLUSIONS: Assembly of tests based on cost-effectiveness can improve clinical efficiency and decrease total cost of panel testing for selected patient groups. (+info)
Safely reducing manual urine microscopy analyses by combining urine flow cytometer and strip results.
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We aimed to reduce the number of manual urine microscopy examinations safely by cross-interpretation of the Sysmex UF-100 (TOA Medical Electronics, Kobe, Japan) and urine strip results such that microscopy would be performed if there was discordance between the UF-100 and urine strip results. We also evaluated the usefulness of the optional UF-100 expert software. We performed 2 studies: study 1 to establish review rules for eventual microscopic examination; study 2, a validation study. Our review rates were 40% and 48% and those of UF-100 software were 16% and 32% for the 2 studies. Our false-positive and false-negative results, among the samples not flagged for microscopic review, were acceptably low. We did not find a good correlation between the microscopic classification of RBC morphologic features and the classification given by the UF-100. Since incorporation of the automated urine strip reader and the UF-100 in routine use, our manual microscopy has been reduced to less than 40%. (+info)
Performance of five non-instrumented urine drug-testing devices with challenging near-cutoff specimens.
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A comparison of five non-instrumented urine drug-testing devices was performed using a challenging clinical specimen set with drug concentrations close to the immunoassay screening cutoffs. The five devices were Syva RapidTest d.a.u. 8, Syva RapidCup d.a.u. 5, Roche TesTcup 5, Biosite Triage, and Casco-Nerl microLINE Drug Screen Card. Sixty clinical specimens for each of the five SAMHSA-specified drug categories were tested by both a scientist and a non-scientist with each result independently read by both. All specimens were also tested on a benchtop automated immunoassay analyzer (Syva ETS using Emit d.a.u. reagents) for comparison and by gas chromatography-mass spectrometry (GC-MS). The non-instrumented devices demonstrated an overall accuracy of 70% (66-74%), based on standard GC-MS confirmation cutoffs, comparable to the Syva ETS analyzer (80%). There was also little difference in overall accuracy between the scientist (71%) and non-scientist (69%), although the non-scientist reported 10 false-positive results (0.7% of 1490 total results or 3.8% of 260 results for drug-free specimens), and the scientist reported only 1 false-positive result (0.07% of 1490 total results or 0.38% of 260 results for drug-free specimens). When device performance was assessed according to drug presence/absence criteria, accuracy generally improved with all devices demonstrating extremely high positive predictive values (0.98-1). (+info)
Human nutritional supplements in the horse. Dehydroepiandrosterone versus androstenedione: comparative effects on the androgen profile and consequences for doping analysis.
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Dehydroepiandrosterone (DHEA) and androstenedione are weak androgens, which need conversion to more potent testosterone in order to enhance anabolic action. Consequences of oral dosing at 1 mg/kg on the urinary and plasma androgen profile of mare and gelding have been evaluated with an analytical method involving conjugate fractionation and selective hydrolysis, group separation, and quantitation by gas chromatography-mass spectrometry with selected ion monitoring of trimethylsilyl ethers. Peak levels of testosterone total conjugates in urine (range 300-6000 microg/L) were attained a few hours after dosing. Renal clearance was fast, so the testosterone detection period lasted only 20 to 33 h, the longest time being generated by androstenedione. The urinary testosterone/epitestosterone ratio for detection of exogenous testosterone in the mare was inoperative after DHEA administration because there was a concomitant increase of epitestosterone, which thereby acted as a masking agent. Androstanediols and androstenediols, as well as some 17-ketosteroids, were additional markers. A transient increase of circulating free testosterone has been evidenced, and this would support possible anabolic/androgenic action by supplementation with DHEA and androstenedione along the oral route. (+info)
Nondigestible oligosaccharides do not increase accumulation of lipid soluble environmental contaminants by mice.
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Supplementing diets with nondigestible fibers that are fermented by the gastrointestinal tract bacteria increases the dimension and absorptive capacities of the small intestine; we hypothesized that this would increase the accumulation of environmental contaminants. This was tested by feeding mice for 6-8 wk diets with fiber at two levels (0 and 100 g/kg) and from different sources (cellulose, lactosucrose, polydextrose, indigestible dextrin, inulin) before a 2-wk oral exposure to (14)C-labeled mirex or methylmercury in combination with (3)H-labeled retinol. Concentrations of contaminants and retinol were measured in urine and feces collected for the last 2 d of exposure and in seven tissues (small and large intestine, brain, liver, kidneys, gastrointestinal tract mesentery, gall bladder). Mice fed the same diets, but not exposed to the contaminants, were used for routine microbiology of alimentary canal contents, measurements of intestinal dimensions and in vitro rates of glucose, mirex, methylmercury and retinol absorption by the small intestine. Mice fed the diets with nondigestible oligosaccharides had higher densities of anaerobic bacteria and larger small and large intestines, but did not have greater rates of contaminant absorption or accumulation. Mice exposed to methylmercury accumulated less retinol than mice exposed to mirex. Although diets with nondigestible oligosaccharides fibers reduce accumulation of environmental contaminants, but not retinol, the specific responses vary among tissues, sources of fiber and contaminants. The mechanisms responsible for the influence of nondigestible oligosaccharides can include reduced absorption, increased fecal elimination and transformation to forms that are excreted in the urine. (+info)