Retinal capillaries: basement membrane thickening by galactosemia prevented with aldose reductase inhibitor

A twofold thickening of capillary basement membranes of rat retinas resulting from dietary galactose was prevented by sorbinil, an inhibitor of aldose reductase. Since the basement membrane thickening was ultrastructurally similar to that typical of diabetic retinopathy, it may indicate changes in vessel permeability and susceptibility to hemorrhage. Galactosemic rats should be useful models for studying basement membrane-related complications of diabetes and for examining the potential biochemical regulation of basement membrane synthesis by aldose reductase inhibitors.     

PJ34对糖尿病大鼠肾脏的保护作用

目的 探讨多聚(ADP-核糖)聚合酶(PARP)抑制剂PJ34对糖尿病大鼠肾脏保护作用及其可能机制.方法 将SD大鼠分为正常对照组、模型对照组、模型治疗组,模型治疗组给予PJ34 10mg/kg,正常对照组及模型对照组给予同等剂量的纯化水.测定尿白蛋白排泄量(UAE)、内生肌酐清除率(Ccr)、血浆及肾组织一氧化氮(NO)、一氧化氮合酶(NOS)、内皮素(ET)、转化生长因子β1(TGF-β1)和肾小球蛋白激酶C(PKC) 水平,并行肾组织形态学观察.结果 4周时,模型对照组Ccr、UAE、NO、NOS及肾小球细胞膜PKC明显高于正常对照组,ET低于正常对照组;8周时,糖尿病大鼠肾小球细胞膜PKC明显高于正常对照组,NO和NOS均低于正常对照组,ET高于正常对照组.8周时模型治疗组大鼠的Ccr、尿白蛋白量和肾小球细胞膜PKC,以及4周时NO、NOS明显低于模型对照组.模型治疗组的肾功能及肾病变明显改善,肾组织中ET水平、TGF-β1表达减少.结论 PJ34对糖尿病大鼠的肾脏有保护作用,可能与抑制PKC、肾脏NO合成及降低肾组织ET和TGF-β1水平有关.     

Study of aldose reductase inhibition in intact lenses by 13C nuclear magnetic resonance spectroscopy

Carbon-13 nuclear magnetic resonance spectroscopy has been used in the study of glucose metabolism, specifically aldose reductase inhibition, in intact rabbit lenses maintained in organ culture. This technique provides an effective method of screening potential inhibitors of aldose reductase under conditions that more closely approximate in vivo conditions than do earlier methods. The aspirin substitutes acetaminophen and ibuprofen were studied as aldose reductase inhibitors and were found to be effective in reducing sorbitol accumulation in lenses exposed to high glucose stress. Results of this work with various inhibitors of aldose reductase are discussed in terms of lens metabolism and implications regarding diabetic complications such as cataract formation.     

Polyol pathway in aorta: regulation by hormones

Aldose reductase is present in human and rabbit aortas and provides a mechanism whereby hyper-glycemia can alter the metabolism of the arterial wall. Aortic sorbitol concentration is regulated by ambient glucose concentration and is increased by epinephrine, isoproterenol, dibutyryl-3',5'-adenosine monophosphate, ouabain, and angiotensin II.     

Lipolysis in homogenates of adipose tissue: an inhibitor found in fat from obese rats

The presence of a lipidbound inhibitor in adipose tissue of rats with hypothalamic obesity may explain the failure of the tissue to release fatty acids on epinephrine stinmulation. Aqueous extracts of tissue from obese animals showed no deficiency of lipase activity, but when whole homogenates of epididymal fat from lean and obese animals were mixed, 25 percent tissue from obese animals reduced by 73 percent the release expected from tissue of lean controls.     

Cooperative control of potassium accumulation by ouabain in vascular smooth muscle

The effects of ouabain on potassium accumulation were studied in the dog carotid artery. It was confirmed that vascular smooth muscle lost potassium in the presence of ouabain greater than 10(-9) molar. This effect could be reversed by systematically increasing potassium in the external medium. The action of ouabain on ion accumulation was represented quantitatively with the application of a recent biophysical approach.     

不同叶面阻控剂对玉米Cd、Pb积累与转运差异研究

为探究不同类型叶面阻控剂对玉米吸收Cd、Pb的阻控效果,实现重金属污染耕地农作物的安全生产,以“华兴单88”为供试玉米,采用田间试验方法,设置8个处理：对照（CK）、YZ-1、YZ-2、YZ-3、YZ-4、降镉灵（JGL）、喷喷富（PPF）和万物生（WWS）,研究不同处理玉米生物性状和各部位Cd、Pb富集及转运系数的差异性。结果表明： 7种叶面阻控剂处理下,产量相较CK提高了4.8%~30.4%,增产能力表现为WWSWWS>PPF>YZ-4>YZ-3>JGL>YZ-2>YZ-1;供试玉米各部位Cd、Pb转运系数均表现为根部-茎部<茎部-棒芯<棒芯-籽粒<茎部-叶部。通过田间试验证明,供试的7种叶面阻控剂对玉米籽粒的Cd、Pb阻控效果表现为YZ-1>YZ-2>JGL>YZ-3>YZ-4>PPF>WWS。本试验条件下,YZ-3作为增产效果最好的叶面阻控剂,建议在Cd轻中度污染的玉米产区推广使用; YZ-1作为Cd、Pb阻控效果最好且成本最低的叶面阻控剂,建议在Cd重度污染的玉米主产区推广使用。     

Participation of an intermediate of oxidative phosphorylation in ion accumulation by mitochondria

Heart mitochondria accumulate massive amounts of Mg(++) and phosphate or Ca(++) and phosphate when incubated under appropriate conditions. Studies with inhibitors of respiration, oligomycin, and uncouplers of oxidative phosphorylation indicate that the energy necessary for these reactions may be provided either in the form of ATP in the absence of electron transport, or in the form of a high-energy intermediate of oxidative phosphorylation, which operates even though ATP is not produced.     

Glutathione reductase: stimulation in normal subjects by riboflavin supplementation

Glutathione reductase of hemolyzates from clinically normal subjects is activated by the addition of flavin-adenine dinucleotide. One-half maximum stimulation could be achieved by approximately 0.02 micromolar flavin-adenine dinucleotide; prior addition of adenosine triphosphate, adenosine diphosphate, or adenosine mnonophosphate prevented activation. Stimulation of glutathione reductase activity of red cells of normal subjects occurred when they were given 5 milligrams of riboflavin daily for 8 days. The degree of stimulation in vitro by flavin-adenine dinucleotide and in vivo by riboflavin was inversely proportional to dietary intake of riboflavin. The variety of clinical disorders which have been associated with glutathione reductase deficiency may have, as a common denominator, abnormalities in flavin-adenine dinucleotide formation.     

广西玉米田间鼠害的调查及防治

为害广西玉米的主要鼠种是板齿鼠、褐家鼠、黄毛鼠、小家鼠等，玉米播种期和乳熟期受灾最严重，采取田间分布取样方法，进行鼠害调查，准确掌握鼠情，制订科学的防治计划，可提高灭鼠效果。     

Alpha-naphthoflavone: an inhibitor of hydrocarbon cytotoxicity and microsomal hydroxylase

Alpha-naphthoflavone inhibits the metabolism of 3,4-benzopyrene and 7,12-dimethylbenz(a)anthracene in hamster enlbryo cell cultures and protects the cells against the inhibition of cell multiplication by these carcinogens. Alphla-nalphthoflavone also inhibits the aryl hydrocarbon hydroxylase activity in homogenates of induced hamster embryo cells and in liver microsomes from rats previously treated with polycyclic aromatic hydrocarbons, but not in microsomes from control rats.     

Object-carrying by rats: an approach to the behavior produced by brain stimulation

Rats were provided with opportunity to turn reinforcing hypothalamic stimulation on and off by traversing back and forth across a chamber. When provided with edible and inedible objects, all animals that self-stimulated carried them from the stimulation to the nonstimulation side. Neither food deprivation nor a history of stimulus-bound eating produced a preference for the edible objects. Equivalent stimulation provided without regard to the animals' location in the chamber did not elicit object-carrying. Results are interpreted in terms of the natural conditions which normally elicit this species-specific unit of behavior. Implications for understanding other behavior patterns elicited by hypothalamic stimulation are suggested.     

Senescence of nickel-transformed cells by an X chromosome: possible epigenetic control

Transfer of a normal Chinese hamster X chromosome (carried in a mouse A9 donor cell line) to a nickel-transformed Chinese hamster cell line with an Xq chromosome deletion resulted in senescense of these previously immortal cells. At early passages of the A9/CX donor cells, the hamster X chromosome was highly active, inducing senescence in 100% of the colonies obtained after its transfer into the nickel-transformed cells. However, senescence was reduced to 50% when Chinese hamster X chromosomes were transferred from later passage A9 cells. Full senescing activity of the intact hamster X chromosome was restored by treatment of the donor mouse cells with 5-azacytidine, which induced demethylation of DNA. These results suggest that a senescence gene or genes, which may be located on the Chinese hamster X chromosome, can be regulated by DNA methylation, and that escape from senescence and possibly loss of tumor suppressor gene activity can occur by epigenetic mechanisms.     

桂皮提取物对糖尿病大鼠血糖和血脂含量的影响

【目的】探讨桂皮提取物对糖尿病大鼠血糖和血脂含量的影响。【方法】给大鼠腹腔注射200mg/kg的四氧嘧啶建立糖尿病模型。试验共分4组:正常对照组(Ⅰ)、糖尿病模型组(Ⅱ)、低剂量桂皮提取物组(Ⅲ)和高剂量桂皮提取物组(Ⅳ),Ⅲ、Ⅳ组糖尿病模型大鼠分别灌服100和200mg/(kg.d)的桂皮提取物,连续灌服30d;Ⅰ、Ⅱ组大鼠分别灌服生理盐水,方法和剂量同前。试验期间观测各组大鼠饮食、尿量,并在0d(开始时)和30d时,取样测定大鼠血糖、血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白(LDL-C)、高密度脂蛋白(HDL-C)水平和体质量。【结果】试验开始时,与Ⅰ组相比,Ⅱ、Ⅲ和Ⅳ组大鼠体质量显著降低(P<0.05),血糖显著提高(P<0.05)。试验结束时,与Ⅱ组相比,Ⅳ组大鼠血糖及血清TC、TG和LDL-C水平显著降低(P<0.05),而体质量和HDL-C水平显著升高(P<0.05);而Ⅳ组与Ⅰ组相比,大鼠体质量、血糖及血清TC、TG、LDL-C和HDL-C水平差异均不显著(P>0.05)。【结论】灌服200mg/(kg.d)的桂皮提取物,能够降低四氧嘧啶所致糖尿病大鼠的血糖及血清TC、TG和LDL-C水平,增加其体质量,提高其血清HDL-C水平。     

Glucose and weight control in mice with a designed ghrelin O-acyltransferase inhibitor

Ghrelin is a gastric peptide hormone that stimulates weight gain in vertebrates. The biological activities of ghrelin require octanoylation of the peptide on Ser(3), an unusual posttranslational modification that is catalyzed by the enzyme ghrelin O-acyltransferase (GOAT). Here, we describe the design, synthesis, and characterization of GO-CoA-Tat, a peptide-based bisubstrate analog that antagonizes GOAT. GO-CoA-Tat potently inhibits GOAT in vitro, in cultured cells, and in mice. Intraperitoneal administration of GO-CoA-Tat improves glucose tolerance and reduces weight gain in wild-type mice but not in ghrelin-deficient mice, supporting the concept that its beneficial metabolic effects are due specifically to GOAT inhibition. In addition to serving as a research tool for mapping ghrelin actions, GO-CoA-Tat may help pave the way for clinical targeting of GOAT in metabolic diseases.     

Carbonic anhydrase and osteoclasts: localization by labeled inhibitor autoradiography

Autoradiography with tritiated acetazolamide indicates that osteoclasts of the hen and chick contain concentrations of carbonic anhydrase which are similar to those in pancreatic acinar cells. Grain counts of osteoblasts and osteocytes were not different from background. Thus, a sufficient quantity of carbonic anhydrase seems to be present in osteoclasts to be of physiological importance in bone resorption.     

农田鼠害防治技术研究中的若干问题

本文综合评述了农田鼠害研究方面的有关问题及主要技术措施的研究进展。指出农田鼠害的有效防治除了需要掌握害鼠本身的发生规律、种群动态等生物生态学特性外，还需研究预测预报，防治指标，损失评价技术，制定防治方案，进而研究各项技术措施。化学防治是当今世界各国鼠害防治的主要手段；在一定的条件下，诱订和稳定捕食性天敌，可以有效地控制害鼠种群数量的恶性增长；不育剂的大面积应用还未取得成功的先例，但可以肯定在不远的未来，包括不育剂在内的遗传防治技术将成为现实；信息素、外激素的应用还存在许多问题；电磁灭鼠已告失败，超声波也难付诸应用；驱避剂的弱点是害鼠很容易适应它们。因此，有效的灭鼠仍然是一个引人注目的问题。     

Production of polydipsia in normal rats by an intermittent food schedule

Marked polydipsia was produced in all animals trained to press a bar for food pellets on a 1-minute variableinterval schedule. It is suggested that since this feeding arrangement produces a sustained, high fluid intake in the normal, unrestrained animal, it might serve as a useful tool in the study of renal function.