Calculation of coronary blood flow from myocardial clearance of systemically administered 133Xe

Clearance curves for arterial and coronary-venous blood were determined after systemic left-ventricle or pulmonary-artery infections of 133Xe, paired with selective left-coronary-artery injections of 133Xe in 20 dogs with closed chest. Coronary blood flows calculated from systemic and coronary-artery injections were comparable only when a correction was made for arteriol recirculation of 133Xe following the systemic injection (r = 0.962) for left ventricle and 0.932 for pulmonary artery, paired with coronary artery). Experiments in four other dogs, verified that clearance of 133Xe from the pulmonary circulation was only about 60%. The myocardium/blood 133Xe partition coefficient, determined in vivo in ten dogs, agreed within 10% with that previously determined in vitro.     

Effect of undernutrition and amino acid deficiency on the timing of puberty in rats

Sexual maturation was examined in underfed or amino acid-deficient rats. We have demonstrated a highly significant negative linear relationship (r = -0.80, P less than 0.001) between the age at puberty and the growth rate in rats under conditions of food restriction. The weight at puberty in animals growing at different rates because of undernutrition was not constant but behaved as a quadratic function of growth rate, as predicted from the assumption that growth rate was an independent variable. Growth rate is therefore more important than arrival at a particular fixed weight in determining the timing of puberty. Feeding of low valine diets resulted in delayed sexual maturation. Both the weight at vaginal opening (182 +/- 5.9 g) and the weight at first estrus (187 +/- 6.1 g) were significantly greater in the valine-deficient group when compared with growth-matched control (139 +/- 10.7 g and 161 +/- 9.3 g, respectively, P less than 0.05). The valine-deficient group also had significantly later vaginal opening (98.8+/- 4.7 days) than growth-matched controls (76.6 +/- 6.6 days, P less than 0.02). Valine deficiency seemed to have a specific effect on the hypothalamic-pituitary-gonadal axis since puberty in valine-deficient animals was delayed more than could be accounted for by impairment of growth.     

Circulatory effects of diazepam in heart disease

Diazepam was administered to ten patients with heart disease during diagnostic cardiac catheterization, in order to determine whether or not this drug's circulatory actions could alter results obtained during the procedure. Diazepam produced no change in baroreceptor sensitivity; however, there was a significant rise in heart rate and a significant fall in aortic systolic and left ventricular end-diastolic pressures. Cardiac index was unchanged, whereas stroke volume fell significantly. Systemic vascular resistance and peak left ventricular dp/dt did not change throughout the study. Clinical response in terms of sedation was judged to be satisfactory in eight patients, and no adverse effect on respiration was noted. Diazepam has little effect on basal circulatory and respiratory parameters when changes in these parameters are averaged for our ten patients. However, substantial changes in hemodynamic parameters did occur in several individuals, and such alteration in circulatory function must be considered when this agent is used routinely in patients having diagnostic cardiac catheterization.     

Studies on the antitesticular action of DL-6-(N-2-pipecolinomethyl)-5-hydroxy-indane (PMHI) in the rat

Both prepubertal and adult rats were treated with a single oral dose of either 60 mg or 120 mg of dl-6-(N-pipecolinomethyl)-5-hydroxy indane maleate (PMHI) per kg of body weight. Their testicular weights were drastically reduced compared with those of the controls. A follow-up, beginning on the third day post-treatment and continuing for a period of 50 days, showed that the body weight growth of PMHI-treated rats was not retarded. The hormonal profile indicated that, except for FSH which showed a transitory elevation in PMHI-treated immature rats, the serum levels of LH, estrogen, and testosterone were indistinguishable from those of the controls. Testicular histology revealed that the spermatogenic process in PMHI-treated rats recovered at a dose-related rate. EM sections of testes of adult rats indicated that cytoplasmic vacuolation appeared in the Sertoli cells 5 h post-treatment. The consequent cascade of arrested spermiogenesis included abnormal acrosomal condensation of spermatids and sloughing of polynucleated spermatids. Some spermatocytes also seemed to be affected, but spermatogonia and Leydig cells remained intact. These results indicate the PMHI acts primarily on Sertoli cells and causes arrest in the spermiogenetic stage of the spermatids. At a higher and toxic dose of PMHI, however, the earlier germinal elements might also be affected, due to the extensive damage to the supporting Sertoli cells.     

Characterization of prostaglandin production in tissue culture of rat renal medullary cells

The purpose of our studies was to examine the role of the nervous system in arrhythmias produced by digitalis overdose and coronary artery occlusion in the cat. This was done by observing the effect of these arrhythmogenic procedures on cardiac efferent neural activity and then determining whether any observed alteration in neural activity contributed to the cardiac rhythm disturbances evoked by digitalis and coronary artery occlusion. Our data indicate that both procedures used to evoke arrhythmias activate each division of the autonomic nervous system. Activation of the sympathetic nervous system resulted in a deleterious effect on cardiac rhythm whereas activation of the parasympathetic nervous system, in general, resulted in a beneficial effect on cardiac rhythm. With coronary occlusion, the role exerted by the nervous system depended on the anatomic location of the involved myocardium. Studies directed at elucidating the mechanisms whereby the nervous system caused cardiac rhythm disturbances indicated that there may be an important difference between the antiarrhythmic efficacy of beta-adrenergic blockade and bilateral stellate ganglionectomy. The latter procedure proved to be a more effective way of removing deleterious sympathetic neural effects on the heart. In conclusion, our findings suggest that the development of new drugs for treating arrhythmias resulting from digitalis and coronary occlusion should be aimed at finding drugs that act to either depress central sympathetic outflow or enhance parasympathetic effects on the ventricle.     

Sodium bicarbonate and alfalfa hay additions to wheat silage diets fed to lactating dairy cows

Two experiments were conducted to examine dietary effects of .8% sodium bicarbonate and 1.4 kg/d of alfalfa hay on performance and rumen metabolism of lactating dairy cows fed 50% wheat silage and 50% concentrate (dry basis). In Experiment 1 with 12 midlactation Holsteins in a 4 X 4 Latin square design, intake, milk production, and milk composition were not affected by treatment. Dietary sodium bicarbonate and alfalfa hay did not alter blood, rumen, or fecal pH. Rumen volatile fatty acid pattern was not affected by sodium bicarbonate, but addition of hay resulted in higher molar percentage propionate and lower acetate: propionate ratios. In Experiment 2 with 32 early lactation cows (20 Holsteins and 12 Jerseys) in a complete randomized block design, supplementation of sodium bicarbonate, alfalfa hay, or both did not affect intake, milk production, or milk composition in the first 8 wk of lactation. Blood, rumen, and fecal pH were not affected by treatment. Dietary sodium bicarbonate did not alter ruminal volatile fatty acid profile, whereas addition of hay increased molar proportion acetate and decreased molar proportion butyrate. A shift in rumen fermentation was observed across treatments from wk 1 through 8 postpartum with molar proportions of acetate and butyrate increasing and molar proportion of propionate decreasing.     

On thin-wire multiturn loop antennas

A general theory of thin-wire multiturn loop antennas is presented. For convenience the windings of the loop are considered to form a circular helix. An integral equation is derived and solved numerically for the current distribution on the antenna. The antenna impedance, efficiency, and pattern are obtained.     

Non-targeted analysis of tea by hydrophilic interaction liquid chromatography and high resolution mass spectrometry

Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the potential of HILIC chromatography combined with non-targeted mass spectrometric methods to provide a comprehensive understanding of polar metabolites in plant extracts.     

乳杆菌耐消化应激能力及消化应激对其肠道黏附能力的影响

首先通过体外模拟唾液-胃液-肠液应激实验研究乳杆菌的耐消化应激能力,然后研究其对肠道黏蛋白和Caco-2细胞的黏附及抑制肠道病原菌黏附的能力,最后探讨消化应激对乳杆菌黏附能力的影响。结果表明,副干酪乳杆菌W125、m111和发酵乳杆菌146在依次经过模拟唾液-胃液-肠液应激后存活率分别为2.70%、3.53%及11.15%,活菌数分别为7.46、7.24(lg(CFU/mL))及8.35(lg(CFU/mL)),且对黏蛋白和Caco-2细胞的黏附率显著高于其他菌株（P<0.05）,分别为15.67%、8.75%、8.38%和11.47%、21.34%、10.44%;3株菌株均可通过排除、竞争和替代的方式抑制大肠杆菌CICC10899和沙门菌WX29对肠道的黏附,黏附抑制率均大于13.51%;消化应激显著降低了副干酪乳杆菌W125和发酵乳杆菌146对肠道的黏附能力（P<0.05）,但显著增加了副干酪乳杆菌m111的黏附能力（P<0.05）,黏附率由17.60%增加到30.45%,且主要黏附素由消化应激前的表层蛋白变为应激后的蛋白和多糖;消化应激前后副干酪乳杆菌m111均...