胰岛素对糖尿病大鼠代谢紊乱的调节作用

利用四氧嘧啶建立糖尿病大鼠模型,研究了胰岛素对糖尿病大鼠脂肪、蛋白质、自由基代谢紊乱的调节作用及对机体和肝脏氧化损伤的保护作用。结果表明,胰岛素0．5U/kg皮下注射8周,能明显抑制糖尿病引起大鼠体重的降低。皮下注射6周,显著提高了血清总蛋白、白蛋白、总胆固醇的水平,降低了血清甘油三酯的含量。胰岛素1U／kg皮下注射9d,能显著提高血清超氧化物歧化酶、谷肮甘肽过氧化物酶的活性,降低血清丙二醛的含量及促氧化酶黄嘌呤氧化酶的活性,提高肝线粒体谷胱甘肽过氧化物酶的活性,降低肝线粒体丙二醛的含量。从而调节糖尿病大鼠脂肪、蛋白质、自由基代谢紊乱,减轻机体的氧化损伤,改善肝功能。     

黄芪多糖预防2 型糖尿病大鼠肝损伤的实验研究

目的:研究分析黄芪多糖(Astragalus polysaecharides,APS)在预防2型糖尿病大鼠肝损伤的作用。方法:Wistar大鼠72只,其中48只以小剂量链脲佐菌素(Streptozotocin,STZ)建立2型糖尿病大鼠模型,并随机分为模型对照组(B组)和APS组(C组),余24只大鼠为正常对照组(A组)。C组大鼠给予APS 400 mg/kg/d灌胃,A、B组分别给予等量生理盐水。分别于第0、2、4、6周检测3组大鼠血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、超氧化物歧化酶(SOD)以及丙二醛(MDA)水平,透射电镜下观察3组大鼠肝细胞超微结构变化。结果:第0、2周时B、C组大鼠ALT、AST、SOD以及MDA水平比较无显著差异(P0.05)。第4、6周时,C组大鼠ALT、AST以及MDA水平均高于A组,但低于B组;而SOD水平低于A组,但高于B组;差异均有统计学意义(P0.05)。电镜下观察,A组肝细胞内大量线粒体、内质网,结构完好,未见损伤;B组细胞器数量减少,线粒体及内质网形态异常,膜结构破损,细胞空化;C组细胞器也存在损伤,但较B组明显减轻。结论:APS可增加肝细胞抗氧化酶的活性,促进氧自由基的清除,减少肝细胞损伤,对预防2型糖尿病引起的肝功能损害有一定的价值。     

Roux-en-Y胃旁路术对2型糖尿病大鼠肝及外周胰岛素敏感性的影响

目的观察RYGB术后不同时间2型糖尿病大鼠肝及外周组织胰岛素敏感性的变化并初步探讨可能机制。方法 RYGB组(n=21)及RYGB假手术组(n=7),采用清醒状态扩展高胰岛素-正血糖钳夹术,评估RYGB术后2、4、8周肝及外周组织胰岛素敏感性。检测肝及腓肠肌内TG水平。结果 RYGB术降低体重,减少体内脂肪,改善脂代谢。术后2周肝胰岛素敏感性指数显著提高,肝TG含量明显下降(P0.05)。术后4周M值显著提高,肌肉TG含量明显下降(P0.05)。结论 RYGB术后肝胰岛素敏感性的提高早于外周组织,肝及外周组织胰岛素抵抗持续改善有助于2型糖尿病的长期缓解。RYGB术减少肝及骨骼肌脂肪沉积可能是术后胰岛素敏感性上调的重要机制之一。     

大鼠再生肝抗CCl4损伤与其线粒体呼吸活性变化的关系

本工作观察了肝部分切除(68%)后96h 大鼠再生肝的抗 CCl_4损伤作用,并用氧电极法测定了再生肝线粒体的呼吸活性。结果如下: (1)CCl_4(50%,10ml/kg)引起的动物死亡率,肝切除组大鼠较假手术组明显降低;(2)CCl_4(50%,5 ml/kg)损伤后,肝切除组大鼠血清胆红素、血清谷丙转氨酶(sGPT)均明显低于假手术组,组织学检查损伤程度也明显减轻;(3)无论是否伴有 CCI_1损伤,肝切除组大鼠肝线粒体的呼吸活性均强于假手术组,且肝线粒体呼吸活性的变化与血清胆红素、sGPT 及肝组织损伤程度的改善是一致的。上述结果提示:再生肝线粒体呼吸活性增高,同时不易受 CCl_4损伤,可能在再生肝抗 CCl_4损伤机制中起一定作用。     

胰岛素对鹅原代肝细胞增殖及蛋白合成的影响

通过用不同浓度胰岛素培养天府肉鹅（Ansercygnoides）原代肝细胞探讨胰岛素对鹅原代肝细胞增殖及蛋白合成的影响。结果表明：与对照组相比,0—200nmol／L胰岛素对肝细胞上清液中谷草转氨酶（AST）、谷丙转氨酶（ALT）浓度没有显著影响,表明细胞功能正常;100、150和200nmol／L胰岛素显著增加细胞培养上清液中总蛋白（什）和白蛋白（ALB）浓度;Brdu．ELISA法检测DNA合成实验结果表明经胰岛素处理后显著增加鹅原代肝细胞增殖率。因此,胰岛素能促进鹅原代肝细胞的细胞增殖及蛋白合成。     

激活PPARγ抑制异烟肼与利福平合用致大鼠肝损伤及HMGB1水平上调

目的探讨激活过氧化物酶体增殖物激活受体γ(peroxisome proliferator-activated receptorγ,PPARγ)对异烟肼与利福平合用致肝损伤的作用。方法以异烟肼和利福平合用制作大鼠肝损伤模型,以15d-PGJ2激活PPARγ。造模第14d和第28d分批处死大鼠,测定血清总胆红素(total bilirubin,TBIL)、直接胆红素(direct bilirubin,DBIL)、谷丙转氨酶(alanine aminotransferase,ALT),、谷草转氨酶(aspartate aminotransferase,AST)水平,观察大鼠肝病理学和超微结构变化,检测大鼠肝组织超氧化物歧化酶(superoxide dismutase,SOD)活性、丙二醛(malondialdehyde,MDA)含量,免疫组织化学测定肝高迁移率族蛋白B1(high mobility group box 1,HMGB1)表达。结果异烟肼和利福平合用所致肝损伤模型小鼠血清TBIL、DBIL明显升高,肝组织SOD活性显著降低,MDA含量升高,肝脂肪变性和炎症细胞浸润较明显,肝细胞线粒体及内质网结构破坏,HMGB1免疫反应性增强;PPARγ激动剂15d-PGJ2处理可明显抑制上述变化。结论 PPARγ激动剂15d-PGJ2可能通过抗氧化及抑制HMGB1表达对异烟肼、利福平合用致肝损伤发挥保护作用。     

糖尿病大鼠肝细胞膜胰岛素受体的变化及机制探讨

本文采用受体的放射配体分析法,观察链佐霉素（ＳＴＺ）糖尿病大鼠肝细胞膜胰岛素受体的变化,并用核酸杂交方法对ＳＴＺ大鼠肝组织胰岛素受体变化的机制进行探讨。主要结果如下,Ｗｉｓｔａｒ大鼠在腹腔注射ＳＴＺ后２周,血糖升高,血清胰岛素水平降低,肝细胞膜胰岛素受体数目增加,与正常对照组相比增加了１５５．６％,而受体结合的亲和力下降。用斑点杂交方法观察到,ＳＴＺ注射２周后,大鼠肝组织胰岛素受体ｍＲＮＡ含量明显增加,而补充胰岛素后,受体ｍＲＮＡ含量基本恢复正常。提示ＳＴＺ大鼠肝细胞膜胰岛素受体数目增加的原因,可能主要是低胰岛素血症引起肝组织胰岛素受体ｍＲＮＡ表达水平增加,而补充胰岛素可使其恢复正常。从而进一步证明,血清胰岛素水平在ＳＴＺ糖尿病大鼠肝细胞膜胰岛素受体的变化中具有重要作用。     

芦笋老茎澄清汁对链脲佐菌素致糖尿病大鼠降糖作用的研究

本文评价了芦笋老茎澄清汁(CAJ)的降血糖作用,并对其降血糖机制进行了初步探讨。腹腔注射STZ制备类似1型糖尿病大鼠模型,以0.6,1.2和2.0 g/kg体重剂量的CAJ连续灌胃21 d,监测血糖,测定糖化血清蛋白、血清胰岛素、肝糖原、脂代谢及抗氧化系统部分相关指标。结果显示,CAJ可明显降低糖尿病大鼠血清中葡萄糖、糖化血清蛋白、总胆固醇和MDA含量,并显著提高受试模型鼠的血清胰岛素水平、肝糖原含量、血清SOD活性、肝脏SOD、GSH-Px和CAT的活性。上述结果表明CAJ可明显降低糖尿病大鼠的血糖水平,刺激胰岛素分泌,调节血脂,增强抗氧化能力。     

青少年食蟹猴糖尿病模型的肝脏病理生理学研究

目的通过对胰岛素用量不足条件下链脲佐菌素诱导的青少年食蟹猴1型糖尿病模型肝脏病理生理学的研究,探讨长期高血糖所致青少年食蟹猴肝损伤特点及机制。方法通过静脉注射68 mg/kg的链脲佐菌素,诱导4只3岁的食蟹猴成为1型糖尿病模型,然后经长期的血糖监测和静脉糖耐量实验来评价该模型的可靠性及稳定性,造模4年后,对模型猴进行血生化、PAS染色、苏丹III染色及普通病理和超微病理等指标的检测,另外选取4只健康与模型猴年龄匹配的猴作为正常对照组,同时进行相应的检测。结果与正常对照组比较,糖尿病猴血清学检测指标中总胆汁酸、尿素氮、谷丙转氨酶、谷草转氨酶、胆碱酯酶、乳酸脱氢酶、总胆固醇、甘油三酯和低密度脂蛋白胆固醇明显升高。组织化学染色结果显示,与正常猴比较,糖尿病猴中央静脉区肝实质细胞肿胀,肝细胞PAS染色（糖原染色）加深,苏丹Ⅲ染色（脂肪染色）阳性细胞增多;电镜结果显示糖尿病猴肝细胞内胞质糖原颗粒增多;线粒体电子密度显著增高,结构不清;窦周隙内含有大量脂滴的肝星状细胞明显增多。结论在长期胰岛素用量不足血糖控制不理想的条件下,青少年食蟹猴1型糖尿病模型肝脏特异性的病理改变是肝糖原贮积和含有大量脂滴的肝星状细胞增生,这些病理改变与非酒精性脂肪肝病的病变特点存在显著不同,但其机制目前尚不清楚。     

Iuteolin对糖尿病大鼠心脏功能的保护作用及其可能机制

目的：研究Iuteolin对链脲佐菌素诱导的Ⅰ型糖尿病大鼠心功能及心肌线粒体氧化应激的影响。方法：雄性SD大鼠,随机分成正常对照组,Iuteolin对照纽,糖尿病模型组,低剂量Iuteolin（10ms／（kg·d））灌胃治疗组,高剂量Iuteolin（100ms／（kg·d））灌胃治疗组。各组大鼠饲养8周后,测体重、血糖、心功能、左心室重量、心肌胶原含量及活性氧自由基（ROS）水平,分离心肌线粒体检测ROS水平、超氧化物歧化酶（SOD）活性及线粒体肿胀程度。结果：Iuteolin处理对糖尿病大鼠血糖无明显影响,但可减少糖尿病引起的体重下降。高剂量Iuteolin可显著减小糖尿病大鼠心室与体重比值,提高左室发展压,降低左室舒张末压。高剂量Iuteolin治疗后,糖尿病大鼠心肌ROS及胶原含量。心肌线粒体ROS水平与肿胀程度均明显下降,心肌线粒体SOD活性明显增加。结论：Iuteolin处理可显著改善糖尿病大鼠心功能．其机制可能与减轻心肌线粒体氧化应激及抑制线粒体肿胀有关。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。