J. Richard Trout

Prevalence, treatment, and control of hypertension in chronic hemodialysis patients in the United States

BACKGROUND Hypertension is common in chronic hemodialysis patients, yet there are limited data on the epidemiology of hypertension in these patients in the United States. METHODS We assessed the prevalence, treatment, and control of hypertension in a cohort of 2535 clinically stable, adult hemodialysis patients who participated in a multicenter study of the safety and tolerability of an intravenous iron preparation. Hypertension was defined as an average predialysis systolic blood pressure >150 mm Hg or diastolic blood pressure >85 mm Hg, or the use of antihypertensive medications. RESULTS Hypertension was documented in 86% (n = 2173) of patients. The prevalence of hypertension, in contrast to that observed in the general population, did not increase linearly with age and was not affected by sex or ethnicity. Hypertension was controlled adequately in only 30% (n = 659) of the hypertensive patients. In the remaining patients, hypertension was either untreated (12% [252/2173]) or treated inadequately (58% [1262/2173]). CONCLUSION Control of hypertension, particularly systolic hypertension, in chronic hemodialysis patients in the United States is inadequate, despite recognition of its prevalence and the frequent use of antihypertensive drugs. Optimizing the use of medications and closer attention to nonpharmacologic interventions, such as adjustment of dry weight, a low-sodium diet, and exercise, may improve control.

Correlation of gas chromatographic profiles and organoleptic scores of different fats and oils after simulated deep fat frying

Five oils and a fat were subjected to simulated deep fat frying using moist cotton balls. The used oils were evaluated by an expert organoleptic panel. Statistically significant differences were found in the odors and flavors of the used oils. Volatile decomposition products of the used oils were quantitatively isolated by high vacuum cryogenic entrainment and then analyzed by gas-liquid chromatography. The volatiles from each used oil yielded a gas chromatogram which was qualitatively and quantitatively different from the others. A statistical analysis was used to correlate the organoleptic scores with the profile gas chromatograms from the used oils. Excellent correlations between gas chromatographic peak areas and organoleptic scores were established. However, limitations in the number of samples tested and limitations in the statistical design do not permit drawing conclusions of cause and effect.

Recombinant alpha-2 interferon gel treatment of recurrent herpes genitalis.

Topical recombinant alpha-2 interferon treatment of recurrent genital herpes was studied in a randomized, double-blind, placebo controlled clinical trial. Three hundred and eighty-seven patients were treated at eight study centers with either interferon gel or placebo four times daily for four days. Interferon therapy caused a 26% decrease in the duration of viral shedding. For male patients, there were also significant decreases in the time to crusting (17%) and duration of pain (34%) and itching (21%). For patients with recurrent genital herpes, treatment with topical interferon was found to be effective in decreasing the duration of viral shedding and, for males, pain, itching and time to crusting.

Effects of Yohimbine on Autonomic Measures are Determined by Individual Values for Area Under the Concentration—Time Curve

A study was conducted to examine tolerability and pharmacodynamics of single doses of yohimbine in healthy volunteers using measures of mood, heart rate, blood pressure, and serum catecholamine levels. Participants were given single oral doses of yohimbine hydrochloride as high as 21.6 mg. Plasma concentrations of yohimbine, epinephrine, norepinephrine, and MHPG (3‐methoxy‐4‐hydroxyphenylethylene‐glycol) were quantified by means of high‐performance liquid chromatography with electrochemical detection. Mood was assessed by visual analogue scale (VAS), the Profile of Mood States, and the Spielberger State Anxiety Index. Yohimbine was well tolerated and rapidly absorbed and eliminated. Dose‐related increases in area under the concentration—time curve (AUC) were observed. Administration of yohimbine in the presence of a high fat meal diminished both the rate and extent of drug absorption. Significant intersubject variability in the pharmacokinetic parameters of yohimbine was observed, with some individuals exhibiting greatly increased oral bioavailability of yohimbine. Increases in blood pressure, respiratory rate, plasma catecholamine levels, and total VAS score were observed in participants with elevated AUC values. The AUC of yohimbine had the largest effect on total VAS score. The results indicate that higher doses of yohimbine are both well tolerated and produce dose‐related increases in AUC, which are associated with more pronounced autonomic effects. Increases in respiratory rate and plasma MHPG appear to be the most reliable pharmacodynamic measures for single oral doses of yohimbine. Individual differences in the pharmacokinetics of yohimbine are important in determining pharmacodynamic effects and should be considered in evaluations of its clinical effectiveness.

Jamaica Bay studies VII: Factors affecting the distribution and abundance of ducks in a New York estuary

Abstract The abundance and distribution of ducks (Anatini, Cairinini, Aythyini, Mergini, Oxyurini) were examined at Jamaica Bay Wildlife Refuge, a coastal estuary on Long Island, New York. The refuge contains a variety of tidal habitats as well two freshwater impoundments. The largest concentrations of diving ducks were present in March and April, and from October through December; while the largest concentrations of dabbling ducks were present from June through December. Thus, diving ducks used the refuge on migration whereas dabbling ducks used the refuge during and following the breeding season. Time of year was thus the most significant factor affecting distribution and abundance. Some species were present all year, including Black Duck Anas rubripes , Mallard A. platyrhynchos , Gadwall A. strepera , and Ruddy Duck Oxyura jamaicensis . Although both dabblers and divers used all areas of the bay, dabblers used both ponds while divers used only the East Pond. Dabbling ducks concentrated in the bay at low tide, and on the ponds at high tide. There were more divers on the bay on a falling tide although tide direction did not influence the abundance or distribution of dabblers. Temperature and wind variables influenced the distribution of all ducks: they used the bay at low temperatures, and rafted in large flocks on the bay in intermediate, Northwest winds. Only the numbers and distribution of dabblers were significantly influenced by cloud cover. We conclude that abiotic factors influence the abundance and distribution of ducks on Jamaica Bay Wildlife Refuge, and that tidal factors should be considered when managing migratory or wintering populations of ducks.

Table of the Percentage Points of the Trivariate t-Distribution with an Application to Uniform Confidence Bands

Tables of the percentage points of the trivariate t-distribution are presented. The tables presented consider the situation when the coordinates are not necessarily equal. In addition percentage points are presented for a fairly large selection of possible correlation structures. Also given are several practical situations where these tables could be used. Emphasized is the use of these tables in obtaining a uniform confidence band for the quadratic model where the associated probability is approximate.

Uniform Confidence Bands for a Quadratic Model

In this paper uniform confidence bands are developed for a quadratic regression model. Tables are supplied to determine a uniform confidence band for the quadratic model in which it is assumed the sum of the cubed deviations of the independent variable about its mean is equal to zero. The uniform confidence band is then compared with the classical competitor, the Scheffit confidence band. A table summarizing the results of this comparison is presented. Finally, an example is examined.

Regular and Inverse interval Estimation of Individual Observations Using Uniform Confidence Bands

Bowden and Graybill construct uniform confidence bands under the familiar simple linear regression model, and use those bands to write joint confidence intervals for expected Y given X = Xo for all Xo in a specified finite range Xa ≤ Xo ≤ Xb . Their approach is extended here to provide joint confidence intervals for individual observations on Y given X, and also for individual X given Y (the inverse interval estimation problem), in both cases using uniform confidence bands constructed for Xa ≤ X ≤ Xb . We show that Bowden and Graybills tables can be used in these applications, and give supplementary tables to cover additional cases which more commonly arise in these new contexts. Asymptotic results are also given, allowing the user to generate additional “table” values. The relative efficiencies of the uniform and Scheffe procedures for inverse interval estimation of individual X given Y are extensively compared. It seems that one need not pay a price in efficiency for the convenience of the uniform proc...

A 12-week randomized clinical trial investigating the potential for sucralose to affect glucose homeostasis

ABSTRACT The discovery of gut sweet taste receptors has led to speculations that non‐nutritive sweeteners, including sucralose, may affect glucose control. A double‐blind, parallel, randomized clinical trial, reported here and previously submitted to regulatory agencies, helps to clarify the role of sucralose in this regard. This was primarily an out‐patient study, with 4‐week screening, 12‐week test, and 4‐week follow‐up phases. Normoglycemic male volunteers (47) consumed ˜333.3 mg encapsulated sucralose or placebo 3x/day at mealtimes. HbA1c, fasting glucose, insulin, and C‐peptide were measured weekly. OGTTs were conducted in‐clinic overnight, following overnight fasting twice during screening phase, twice during test phase, and once at follow‐up. Throughout the study, glucose, insulin, C‐peptide and HbA1c levels were within normal range. No statistically significant differences between sucralose and placebo groups in change from baseline for fasting glucose, insulin, C‐peptide and HbA1c, no clinically meaningful differences in time to peak levels or return towards basal levels in OGTTs, and no treatment group differences in mean glucose, insulin, or C‐peptide AUC change from baseline were observed. The results of other relevant clinical trials and studies of gastrointestinal sweet taste receptors are compared to these findings. The collective evidence supports that sucralose has no effect on glycemic control. HIGHLIGHTSGut taste receptor research has led to questions on low calorie sweeteners in glycemic control.Effects have been hypothesized based mostly on cellular and/or short‐term animal studies.Reported is a 12‐week clinical trial investigating the effects of sucralose on glycemic control.Sucralose had no effect on fasting or post‐prandial glucose, insulin and C‐peptide, or HbA1c.The collective evidence is reviewed and supports that sucralose is without effect on glycemia.

Fenfluramine-induced behavior changes in rats prefed serotonin-altering amounts of tryptophan and pyridoxine.

It has been well established that elevated dietary tryptophan (TRP) levels can increase brain serotonin concentrations, thereby influencing serotonergic transmission. We previously examined interaction between dietary substrate (TRP: 0.15 and 0.6%) and the cofactor precursor (pyridoxine HCl: 3 and 3,000 mg/kg) on brain serotonin metabolism, observing significant increases in serotonin concentrations from such dietary interaction. The present experiments were designed to explore possible behavioral consequences of the substrate-cofactor interaction. After the IP injection of fenfluramine (FA: at 5, 10, 15, and 20 mg/kg), serotonin-mediated behavior traits and the appearance of flushing were observed in rats fed experimental diets as stated above. With a 5 mg/kg dose of FA, a differential dietary effect was most visible. However, at higher FA levels (15 and 20 mg/kg), such dietary effects were no longer discernible. The appearance of flushing was also dependent on dietary TRP intake and the dosage of FA. These results indicate a clear substrate-cofactor interaction on certain serotonin-mediated behavior traits in the rat.