Publications by authors named "Selwyn M"

The study of plant-frugivore interactions is essential to understand the ecology and evolution of many plant communities. However, very little is known about how interactions among frugivores indirectly affect plant reproductive success. In this study, we examined direct interactions among vertebrate frugivores sharing the same fruit resources.

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This report describes the results of a survey designed to evaluate the contribution of F1 neurobehavioral testing to hazard identification and characterization in safety assessment studies. (To review the details of the distributed survey, please see the supplementary data for this article on the journal's Web site.) The survey provided information about studies completed in industrial laboratories in the United States, Europe, and Japan since 1990 on 174 compounds.

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Background: Postoperative air leaks are a major cause of morbidity after lung resections. This study was designed to evaluate the efficacy and safety of a new synthetic, bioresorbable surgical sealant in preventing air leaks after pulmonary resection.

Methods: In a multicenter trial, 172 patients undergoing thoracotomy were randomized intraoperatively in a 2:1 ratio to receive surgical sealant applied to sites at risk for air leak after standard methods of lung closure (treatment group) or to have standard lung closure only (control group).

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A high-affinity Ca(2+)-ATPase was solubilized from rat parotid plasma membranes and purified by concanavalin A and DEAE-cellulose chromatography. The properties of the purified high-affinity Ca(2+)-ATPase are very different from those of the parotid plasma membrane ATP-dependent Ca2+ pump but appear to be similar to those of a rat liver cell adhesion protein which exhibits high-affinity ecto-Ca(2+)-ATPase activity.

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A low molecular weight thermostable cytoplasmic fraction isolated from rat liver homogenate when pre-incubated with mitochondria increases the rate at which anions enter mitochondria via the pH-dependent anion-conducting channel in the inner membrane. The crude fraction obtained by centrifuging and heating the liver homogenate was purified by gel filtration and chromatography on DEAE-cellulose. The resulting factor is stable to heating at 100 degrees C, freeze-drying and extremes of pH.

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We propose the use of Gaussian mixed models to analyse statistically 24 hour ambulatory blood pressure data from clinical trials. We develop specific models and apply them to data from a clinical study that compares two angiotensin-converting enzyme inhibitors. We investigate and discuss computing issues related to the implementation of such methods.

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Zinc is a potent reversible inhibitor of the pH-dependent anion-conducting channel in the mitochondrial inner membrane, 50% inhibition was produced by 1.5 microM added Zn2+ at which point free Zn2+ was < or = 10(-8) M. Inhibition by Zn2+ is rapid but can be prevented or rapidly reversed by excess EDTA.

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The effects of buffers and osmolality of the suspending medium on the pH-dependent anion uniport across the inner membrane of isolated rat liver mitochondria have been studied using the light scattering technique to measure passive osmotic swelling. In contrast to some other transport processes the rates of entry of chloride and other anions via the anion-conducting channel decreased steeply with increasing solute concentration. This effect appears to be a result of increased osmolality or decreased matrix volume rather than inhibition by the anion since it was also produced by increasing the osmolality by addition of non-penetrant solutes.

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This study indicates that some current procedures used in thermocycling dental restorative materials would not produce the desired thermal gradient in the specimens. The shortfall in gradient depends on the size of the specimen, the dwell time in the baths and whether the baths are stirred or not. The desired thermal gradient of 50 degrees C can be approximated with a dwell time of 60 s in well-circulated water baths at 5 degrees C and 55 degrees C.

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Stimulation of the rat liver mitochondrial inner-membrane anion-conducting channel by aeration is dependent on the concentration of Ca2+ ions in the assay medium. Ca2+ activates anion conduction in both aerated and non-energised mitochondria but acts over a wider concentration range and produces a greater increase in anion-conductivity in aerated mitochondria. EGTA reverses Ca2+ stimulation but takes several seconds to act, indicating slow release of Ca2+ from the activation site possibly on the matrix side of the inner mitochondrial membrane.

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1. When mitochondria are stirred in air the rate of anion conductivity increases, this effect being enhanced by the addition of respiratory substrate. 2.

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The interpretation of statistically significant findings in a carcinogenicity study is difficult, in part because of the large number of statistical tests conducted. Some scientists who believe that the false positive rates in these experiments are unreasonably large often suggest that the use of multiple control groups will provide important insight into the operational false positive rates. The purpose of this paper is 2-fold: to present results from two carcinogenicity studies with dual control groups, and to present and illustrate a new graphical technique potentially useful in the analysis and interpretation of tumor data from carcinogenicity studies.

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Palmitoyl-CoA is shown here to inhibit the pH-dependent anion-conducting channel (IMAC) in the inner membrane of rat liver mitochondria, with half-maximal inhibition at 2.4 microM. It has little effect on the transport of ribose, thiocyanate and glutamate.

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Both Mg2+ and oligomycin are required for the establishment of a membrane potential and the uptake of Cl- in submitochondrial particles prepared from rat liver. The effect of oligomycin is considered to be due to blocking of H+ conduction through exposed F0 channels of the ATPase complex whereas Mg2+ may more directly affect the anion-conducting channel.

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Bayesian methods are presented for assessing bioequivalence for studies in which a new formulation and a standard are administered simultaneously, and for Latin square designs which compare two or more new formulations to a standard. Two examples illustrate the application of the methods.

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A battery of drugs with antirheumatic properties was tested for effects on the progress of osteoarthritis induced by a lateral meniscectomy procedure in knee joint cartilage of rabbits. Oral administration of the potent glucocorticoids, paramethasone acetate or triamcinolone, resulted in dramatic inhibition of cartilage degeneration. Significant protection against development of osteoarthritic lesions was also observed in rabbits treated with pirprofen or CGS 5391B but not with 9 other nonsteroidal antiinflammatory drugs.

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A partial lateral meniscectomy procedure has been developed for the induction of a predictable and reproducible degenerative joint disease in knees of rabbits. The procedure adopted involves section of the fibular collateral and sesamoid ligaments and removal of 4-5 mm of the anterior lateral meniscus. In most experiments the animals are killed and tissues obtained for histologic examination at 6 weeks.

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The carboxyl group reagent dicyclohexylcarbodiimide inhibits the electrogenic entry of Cl- and NO3-into rat liver mitochondria at alkaline pH. The inhibition is time dependent and 50% inhibition is obtained by the addition of 3-4 nmol DCCD/mg protein. The blockage of the pH-dependent anion-conducting pore appears to be unrelated to the other known actions of DCCD on rat liver mitochondria but seems similar to its effect on the uncoupling protein of brown adipose tissue.

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1. The proteolipid fraction isolated from rat liver mitochondria pretreated with [3H]triphenyltin chloride is enriched in triphenyltin compared with the original mitochondria. 2.

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