Mitogenicity of autolysates of Trypanosoma congolense

Autolysates of Trypanosoma congolense, in subcytotoxic amounts, were found to be highly mitogenic in vitro for the spleen cells of normal mice. Significant amounts of [3H]-thymidine were also incorporated by the responding spleen cells of nu/nu (athymic) mice. In contrast, the spleen cells of cyclophosphamide-treated mice were unresponsive. The findings suggest that a potent B-cell-mitogen is generated by the autolysing T. congolense organism.     

Combined action of nickel sulfate and x-irradiation on human lymphoblastoid leukemic cells]

In a first experiment, cells were cultured in media supplemented by nickel sulphate, irradiated in same media and cultured in same media after irradiation. In a second experiment, cells were cultured during 18 hrs. in media supplemented by nickel sulphate, and then cells were washed and cultured in normal media where they were irradiated. The nickel sulphate toxicity appears as a creasing function of the nickel sulphate concentration and the nickel sulphate action endurance. The nickel sulphate toxic effect is amplified by X-Rays. This amplification is a time function that depends on the X-Ray dose, nickel sulphate concentration and period of time from the outset of culture to the irradiation. The nickel sulphate toxic effect appears faster when nickel works after X-Rays.     

Velocity sedimentation of tumor cells: A comparison of methods

Summary Tumor cells isolated from a murine fibrosarcoma were grown in primary culture for two days and then separated on a basis of size by velocity sedimentation. Centrifugal elutriation and STAPUT methods were compared for their ability to isolate biophysically unique tumor subpopulations. The isolated cell fractions were assayed for cell number, incorporation of triatiated thymidine and Coulter volume. Both methods were comparable with regard to ability to separate tumor cells on a basis of size. Elutriation had the advantage of speed but required sophisticated equipment. The STAPUT method was less expensive but required somewhat longer times for separation.Supported in part by NIH-NCI grants No. CA-06294 and CA-18628.     

Effect of acute and chronic ethanol ingestion on the content of reduced glutathione of various tissues of the rat

Summary The effect of acute ethanol ingestion (5 g/kg) by fasted rats, or chronic treatment in fed animals, revealed a significant decrease in the content of reduced glutathione of the liver and kidney. No changes were observed in reduced glutathione levels of the pancreas, intestines, stomach or spleen in the acute model. In this condition, the time course study of the decrease in reduced glutathione levels showed a progressive effect in the liver and a rapid and constant effect in the kidney.These studies were supported by the Grant M 308-792 from the Servicio de Desarrollo Cientifico, Artistico y de Cooperacion Internacional, Universidad de Chile, and by the Research Associateship Program (L.A.V.) from the Natural Sciences and Engineering Research Council of Canada.     

Microbial methylation of benzenethiols and release of methylthiobenzenes

Three phylogenetically diverse microorganisms methylated several different chloro- and nitro-substituted benzenethiols to yield the corresponding methylthiobenzenes. These products were identified by gas chromatography-mass spectrometry. In several cases large percentages of the methylthio products were released by intact cells into the medium, suggesting that microbial methylation of xenobiotic thiols may be a significant biotransformation in many ecosystems.     

The effect of postnatal undernourishment on epileptiform kindling of dorsal hippocampus

Summary Rats were undernourished postnatally from birth through 20 days of age. They were subsequently tested for susceptibility to motor seizures kindled in hippocampus in adulthood. Compared to littermate control animals the postnatally undernourished rats were more susceptible to the kindling treatment. We conclude that early postnatal undernourishment has a permanent effect on susceptibility of the hippocampus to electrically-induced seizures.This work was supported by Public Health Service grant NS 13799, National Science Foundation grant GB 35532, and by Hoffman-LaRoche, Inc.     

X-ray microanalysis of mast cells in rat's muscle

Summary Mast cells from rat's tongue muscles, fixed with glutaraldehyde only, were examined with an electron microscopic microanalyzer — the EMMA-4. With the preparatory method used, high emissions of a number of elements were obtained in various intracellular spots. The granules of mast cells were found to contain strictly localized high concentrations of sulphur, calcium and zinc.This work was supported by a grant from the MRC. Funds for the purchase and running cost of the instrumentation were provied by the SRC.     

Occurrence,distribution and nature of neuropeptide Y in the rat pancreas

Summary Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.     

Relativity of motion: From Occam to Galileo

Early observations of the southern celestial sky were reported in many sixteenth-century books and compilations of voyages of discovery. Here we analyse these accounts in order to find out what was really seen and reported by the first navigators. Our analysis had resulted in new interpretations of the phenomena reported by Amerigo Vespucci and Andreas Corsali. Thus, a reassessment of the discovery of the Coalsack Nebula, the Magellanic Clouds, and the Southern Cross can be made. From a comparative review of the observations of the latter constellation as published between 1500 and 1600, we demonstrate that only questionable records found their way to contemporary compilations of voyages of discovery, and that as a result public knowledge about this constellation at the end of the sixteenth century was entirely unreliable. Another problem we discuss is that although the stars of the Southern Cross were the first to be discovered, and were observed again and again by many navigators, it was not until 1678 that their proper positions were found in stellar atlases and star catalogues accessible to astronomers. We explain how negligence of and subsequently confidence in Ptolemy's astronomy by, respectively, the early navigators and cartographers, were at the root of this amazingly long-lasting gap in the knowledge of the southern celestial sky.     

枸杞多糖对人肺腺癌 A549细胞增殖和凋亡的影响

目的探讨枸杞多糖(LBP)对体外培养的人肺腺癌细胞 A549的增殖抑制作用及其可能的作用机制.方法用不同浓度的LBP处理 A549细胞,MTT法检测24、48、72h时间点 LBP对 A549细胞的生长抑制率,实验设为对照组和实验组(1/2IC50作用48小时),MTT法绘制生长曲线、细胞计数计算倍增时间、流式细胞仪检测凋亡率及其细胞周期、RT PCR检测 SurvivinmRNA的变化、Westernblot检测 CyclinB1蛋白的变化,transwell体外侵袭实验观察药物对细胞体外侵袭的影响.结果 MTT显示不同浓度的LBP均能明显抑制 A549细胞的增殖且成剂量 效应关系,实验组细胞的倍增时间、凋亡率与对照组相比,均有统计学意义(P<0.05);LBP使细胞阻滞在 G2期,SurvivinmRNA表达和 CyclinB1蛋白的表达均降低,与对照组相比差异有显著性(P<0.05).结论 LBP可抑制 A549细胞的增殖,其机理可能与 LBP使 SurvivinmRNA表达下降引起细胞凋亡及 CyclinB1蛋白的表达降低造成细胞周期阻滞及抑制细胞的侵袭能力有关     

Accumulation of 3H-dopamine by synaptic vesicles from rat striatum in an impermeant medium

The accumulation of 3H-dopamine by synaptic vesicles from rat striatum was significantly stabilized in a membrane impermeant medium. The characteristics of dopamine accumulation by striatal vesicles were quite similar to those reported for dopamine accumulation by a whole brain vesicle preparation in the same medium, and were significantly different from the characteristics previously reported for vesicular accumulation of norepinephrine.     

Occurrence, distribution and nature of neuropeptide Y in the rat pancreas

Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.     

Inhibition of IgM antibody-mediated aggregation of Trypanosoma gambiense in the presence of complement.

This paper deals with the immune reaction between Trypanosoma gambiense and monoclonal IgM mouse antibody at equivalence with or without rabbit complement. Antibody-mediated trypanosome clumps formed in the absence of complement, and were readily dissociated by complement to become free. In the presence of complement, on the other hand, T. gambiense were not aggregated by the antibody. Free parasites adhered readily to cultured peritoneal macrophages. Complement-mediated dissociation of the clumped trypanosomes in the equivalence area released a large number of previously bound surface antigens. These antigens were capable of binding again to fresh IgM antibody. Experimental results further indicated that the complement system caused a functional alteration, changing the multivalent nature of the IgM antibody in the immune complex into a univalent one. This phenomenon is of great advantage to the infected host in clearing pathogens in vivo, as it allows more antibodies to attach to trypanosomes and subsequently initiate complement activity.     

Absorption of protein in the early postoperative period in chronic conscious dogs

Postoperative alterations in amino acid exchange across the intestinal tract and in the capacity for protein absorption were investigated in a chronic canine model. Changes in postoperative splanchnic amino acid exchange consisted of a temporary decrease of total splanchnic amino acid release, including a significant reduction in alanine production, and an increase in glutamine consumption. Contrary to results under stable metabolic conditions, branched chain amino acids were also taken up by the intestine in the early postoperative period. The changes in postoperative amino acid exchange were not, however, reflected by a corresponding alteration in protein transport capacity. The absorptive capacity for a protein hydrolysate remained stable during the early postoperative period.     

Comparison of retinal pigment epithelium cell preparations from the bovine eye

Retinal pigment epithelium (RPE) cells were collected from bovine eyes using a new method. The cells were harvested by vortexing the RPE and underlying choroid in 0.05 M citrate phosphate buffer, pH 5. RPE cells recovered by this method were compared to a standard method by microscopic examination of cell integrity, estimation of total protein, and assay of 11-cis and all-trans retinyl ester hydrolase (REH) activities. Results suggest that this method collects RPE cells of good integrity and with a significantly higher protein yield than the conventional method. Additionally, a much higher retinyl ester hydrolase activity was noted. Therefore we propose that this procedure offers a new and convenient method in the collection of RPE proteins for certain purposes such as enzyme purification.     

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Summary Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. These was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).Acknowledgments. This work was supported, in part, by a grant (HL-03299) and a Research Career Award (HL-00734) from the National Institutes of Health, and by funds from Mary L. Smith and the Commonwealth of Pennsylvania.     

A fast transient osmotic method. Simultaneous in vivo determination of the reflexion coefficient and of the permeability/filtration coefficient ratio of the pulmonary capillary endothelium in the dog]

Thermodynamic variables characterizing the transport of water and urea across Dog pulmonary capillary membrane were obtained in vivo by means of a pulse transient osmotic method. Results were inconsistent with the hypothesis of a homoporous membrane. When data were interpreted in terms of an exclusive water channel and of a shared pore pathway, the value of the pore reflexion coefficient was close to zero for urea.     

Effects of inhibition and stimulation of Na+-K+ active transport on the resting membrane input conductance of the guinea-pig ventricle

The effects of inhibition by ouabain and stimulation by high frequency drive of the sarcolemmal Na+-K+ active transport system on the resting input conductance (gi) of guinea-pig ventricular muscles were determined. Although both pump inhibition and stimulation were associated with changes in electrophysiological properties of the muscles, neither had a significant effect on gi.     

A comparative study of the innervation of the choroid plexus in amphibia

The aminergic and cholinergic innervation of choroid plexuses in three species of amphibia was investigated. Plexuses of the Japanese toad and the bullfrog had poor innervation by adrenergic nerves of sympathetic origin, but in the clawed toad, these plexuses were heavily innervated by adrenergic axons from ganglion cells located in the plexus stroma. Nerve fibers positive for acetylcholinesterase were not found in the plexuses, except for a few fibers with very weak enzyme activity in the clawed toad.     

Mitogenicity of autolysates ofTrypanosoma congolense

Summary Autolysates ofTrypanosoma congolense, in subcytotoxic amounts, were found to be highly mitogenic in vitro for the spleen cells of normal mice. Significant amounts of [³H]-thymidine were also incorporated by the responding spleen cells of nu/nu (athymic) mice. In contrast, the spleen cells of cyclophosphamide-treated mice were unresponsive. The findings suggest that a potent B-cell-mitogen is generated by the autolysingT. congolense organism.Acknowledgments. This investigation was supported by the International Development Research Centre, Canada.