Biomedical subjects
R Brown
Publications and source records attributed to R Brown.
Tissue distribution of 3H-canrenoate potassium in rabbits.
Plasma and various organ concentrations of canrenone, canrenoate, and total 3H-activity were measured following single doses of 20 mg of 3H-canrenoate/kg iv to rabbits. Organs studied included heart, lungs, brain, kidneys, liver, adrenal glands, and spleen. Canrenoate was shown to be in rapid equilibrium with canrenone. Both were eliminated from plasma and other tissues with a half-life of about 1 hr. Plasma concentrations of both drugs were equal as early as 10 min after intravenous drug administration. Canrenone was concentrated about 10-fold in organ tissues when compared to plasma, while no such preferential uptake was found with canrenoate. Total 3H-activity declined slowly in all tissues with a half-life of approximately 15 hr, indicating extensive metabolism and metabolite retention in the rabbit.
Recovery of anaerobic bacteria from small inocula: a model for blood culture studies.
The recovery of anaerobic, facultative anaerobic, and aerobic pathogens from very small inocula was studied under conditions that could be related to routine blood culture procedures. Results with Brain Heart Infusion broth were unsatisfactory. Freshly prepared Brewer thioglycollate medium gave apparently good results, but there are disadvantages when this medium is used for blood culture. Results with Difco Thiol broth were disappointing. A modification of Robertson's cooked-meat broth supplemented with Brain Heart Infusion gave good recovery and sustained viability with a wide range of test organisms including exacting strains. The findings raise points of practical importance.
Effects of intravenous histamine on pulmonary mechanics in nonasthmatic and asthmatic subjects.
Histamine is thought to be one of the primary mediators of the airways response in allergic asthma. We have studied in detail in nonasthmatic and asthmatic volunteers the effects of its intravenous infusion on pulmonary mechanics. The doses used were similar in both groups and limited by vascular rather than pulmonary effects. Measurements were made of lung resistance, the subdivisions of lung volume, maximal flow, density dependence, lung elastic recoil and dynamic compliance. The only mean group changes were a decrease in dynamic compliance and increase in frequency dependence of compliance in the nonasthmatics. Although in nonasthmatic individuals, statistically significant changes occasionally occurred in some parameters, the response was variable on repeated studies and sufficiently small to be of questionable physiological significance. Some of the asthmatics developed larger changes, but these only occurred in those individuals whose preinfusion pulmonary function was abnormal. Our results suggest the possibility that altered prechallenge pulmonary function rather than an unusual sensitivity to histamine may determine the greater responses observed in asthmatics.
The Harlem regional stroke program: an overview.
The Harlem regional stroke program has been a demonstration model designed to detect, treat, and follow up stroke and hypertension patients through collaboration with a municipal teaching hospital, community practitioners, local service organizations and a major medical school. Many aspects of the stroke program appear suitable for replication at the local or regional levels in varied settings. In particular, the program has demonstrated the need to link community outreach programs, stressing early detection and preventive-care education, with sustained treatment and follow-up programs. The stroke program has also suggested ways in which specialized programs can be incorporated into long-term comprehensive health planning and care facilities at local and regional levels.
Spring cantilever bridge design for single and double pontics.
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Synthesis and reactions of 7,8-dihydro-8-methylpterin and 9-methylguanine 7-oxide.
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Mirex residues in nontarget organisms after application of 10-5 bait for fire ant control, northeast Florida--1972-74.
The 10-5 bait formulation of mirex insecticide was applied to a 20,000-acre area of northeast Florida. For 24 months after application, samples of a wide variety of fauna were collected and analyzed for mirex content. Insects accumulated mirex to the greatest extent in the first 6 months after application; most residues had decreased greatly by 12 months. Other invertebrates showed low mirex levels during the first 9 months after application and none after 12 months. Fish possessed low levels of insecticides for 9 months; amphibians showed mirex residues for 12 months after application. In general, reptiles had low levels throughout the 24-month period and mammals had higher levels, particularly in fat tissues. Birds consistently had low to moderate mirex levels. After a single application of 10-5 mirex bait, only relatively low levels of insecticide were detected in exposed fauna. After 24-months, mirex was found infrequently and at low levels.
Alpha1-fetorprotein concentrations in maternal serum during normal pregnancy.
Measurement of amniotic fluid concentrations of alpha1-fetoprotein has been proposed as a potentially important screening test of fetal well-being. Because maternal serum is more easily obtainable, the present study was performed to determine if there is a definable normal pattern of maternal serum alpha1-fetoprotein levels during gestation. Sequential alpha1-fetoprotein determinations were performed throughout gestation on the serums of 151 women having apparently normal pregnancies. Before 13 weeks, all samples contained less than 20 nanograms of alpha1-fetoprotein per milliliter of serum, and in 12.5 per cent of normal pregnancies, alpha1-fetoprotein was still undetectable as late as 21 weeks of gestation. One normal term delivery followed a negative alpha1-fetoprotein determination at the 24th week of pregnancy. Beyond the 21st week of pregnancy, there was a wide range of normal absolute values noted between women at the same stage of pregnancy. Moreover, wide fluctuations in maternal serum concentrations of alpha1-fetoprotein were observed from point to point in specimens from individual women studied longitudinally throughout gestation. The distribution of alpha1-fetoprotein concentrations at each stage of pregnancy was skewed. We conclude that studies of maternal serum alpha1-fetoprotein concentrations are likely to be more meaningful from a diagnostic point of view prior to 21 weeks of gestation, when the range of circulating maternal alpha1-fetroportein values is relatively small. Undetectable maternal serum alpha1-fetoprotein as late as the 24th week of pregnancy is compatible witha viable conceptus. Because unexplained and marked elevations of maternal alpha1-fetoprotein may occur, particularly in the third trimester, it would appear inappropriate to base clinical decision on maternal serum alpha1-fetoprotein measurements alone, and such decisions certainly should not be taken after only single maternal serum alpha1-fetoprotein measurements. Finally, no correlation was found between maternal alpha1-fetoprotein concentrations near term and the birth weight of the infant.
Effects of storage on the methaemoglobin content of equine blood.
Equine blood containing different levels of methaemoglobin was stored under varying conditions and the methaemoglobin content was monitored during the storage period. Only under aerobic storage at 4 degrees C did the methaemoglobin content of all samples appear to remain stable.
Successful renal transplantation in Wegener's granulomatosis.
Two patients with Wegener's granulomatosis, who were in complete remission secondary to cyclophosphamide therapy but who had end-stage renal failure, were treated with renal transplantation. Neither patient has clinical evidence of recurrent glomerulonephritis 10 and 28 months after receiving the renal transplants. Cytotoxic therapy has been proved to be highly effective in inducing and maintaining remission in patients with Wegener's granulomatosis; thus increasingly larger numbers of patients will be seen who, despite being maintained in complete remission, will have markedly impaired renal function due to previous acute damage. Renal transplantation can now be considered an acceptable alternative form of therapy in such patients.
Tests of performance of anaerobic jars.
This paper briefly reviews methods of assessing the in-use performance of anaerobic jars and outlines a simple system combining a rapid test of catalytic activity with a biological indicator that can detect defects in the jars after incubation.
Effect of volume history on successive partial expiratory flow-volume maneuvers.
In normal subjects, the second of two successive partial expiratory flow-volume (PEFV 2) curves often had higher isovolume maximal expiratory flow rates (Vmax) than the first (PEFV 1) (mean increase 30.2 +/- 13%). The higher Vmax on PEFV 2 was present only when there was a greater lung elastic recoil pressure (Pst(L)). In eight subjects the Pst(L) derived from sequential partial quasi-static pressure-volume curves, from interruption of the flow-volume maneuvers and at the start of the PEFV curves showed that isovolume upstream resistance increased although Vmax also increased after going to residual volume (RV). In four subjects the RV volume history did not change the pressure flow relationship across the upstream airways. If airways dimensions were the sole determinant of Vmax, then Vmax on PEFV 2 would be the same or smaller than on PEFV 1. That the opposite was observed in our study indicates that the increase in Pst(L), which results from parenchymal hysteresis, offsets any dimensional decrease in upstream airways due to airways hysteresis.
Letter: Abnormal lung elasticity in juvenile diabetes mellitus.
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Common antigens of Herpex simplex virus 2, associated hamster tumors, and human cervical cancer.
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Colorectal cancer: diagnosis, natural history, and treatment.
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Letter: Polymeric type-III collagen in inflamed human synovia.
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