Production and characterization of a monoclonal islet cell surface autoantibody from the BB rat

Summary Islet cell surface autoantibodies are present in the serum of the spontaneously diabetic BB rat. The availability in large quantities of such autoantibodies should help us understand their significance in vivo. Fusions between BB rat lymphocytes and rat myeloma cells were screened by cellular enzyme linked immunosorbent assay and indirect immunofluorescence on rat living cells. They resulted in a stable hybridoma, called IC₂, secreting a monoclonal immunoglobulin M specific for the surface of rat islet cells. This monoclonal antibody was found to bind to the surface of 56% normal rat islet cells and 72% rat insulinoma cells. Protease treatment of rat islet cells resulted in a subsequent 72–100% binding inhibition of IC₂ to the surface of these cells, suggesting that IC₂ specific antigen is a protein.     

Comparative chemotherapeutic investigations on transplanted and autochthonous acute rat leukemias

Summary The effect of a clinically active drug combination (vincristine, adriamycin, cytosine arabinoside) against (1) a transplanted acute rat leukemia (L 5222) and (2) autochthonous acute rat leukemias is compared in a non-toxic dose range. After four therapy cycles without therapy-free intervals, the animals with transplanted leukemia died; remissions were not achieved. In all rats with autochthonous leukemia the same treatment that was additionally interrupted by therapy-free intervals of 1 week caused complete remissions.The different reactions of both leukemia types to this treatment are mainly due to their kinetic differences. The comparability of transplanted and autochthonous rat leukemias with human acute leukemia is discussed.Dedicated to Prof. Dr. Ch. B. Huggins, Chicago, on the occasion of his 80^th birthday     

The Actions of Dopamine on the Blood Pressure and Heart Rate of Conscious Hypertensive Rats: Evidence for Reduced Dopaminergic Activity in Rats of the Japanese Strains

The effects of intracerebroventricularly (icv) and intravenously (iv) administered dopamine (DA) on mean arterial pressure (MAP) and heart rate were investigated in conscious spontaneously hypertensive rat (SHR), stroke-prone SHR (spSHR) and normotensive Wistar-Kyoto (WKY) rat of Japanese strains, genetically hypertensive (GHR) and normotensive (NT-NZ) rat of New Zealand strains, Sprague-Dawley (SD) rat, and left renal artery stenosed hypertensive WKY (WKYLRAS) and SD (SDLRAS) rats. Icv DA (0.0125-0.4 mg/kg) caused a linear dose-related decrease in MAP, accompanied by bradycardia in all animals. By contrast, the same doses of DA given iv caused a linear dose-related increase in MAP, accompanied by reflex bradycardia in most groups (except the spSHR, SHR and WKYLRAS where tachycardia occurred to most of the doses employed), indicating that the decrease in MAP following icv DA is centrally-mediated. A “greater” relative hypotensive effect to icv DA was seen in the Japanese hypertensive strains SHR and spSHR compared to the WKY, but not between the New Zealand strains or the renal hypertensive animals. Our data also show that this marked hypotensive responsiveness is not related to the basal MAP, but appears to be strain-specific. It is thus possible that the alleged reduced central dopaminergic activity in the Japanese strains of hypertensive rats may be responsible for exaggerated hypotensive responses observed in these strains.     

Electrofocusing fractionation and characterization of pituitary follicle-stimulating hormone from male and female rats

Extracts of male and female rat pituitaries were fractionated by electrofocusing on sucrose density gradients and the pH distribution of FSH determined by an FSH in vitro bioassay, rFSH radioimmunoassay (RIA) and FSH radioreceptor assay (RRA) method. FSH for both sexes was located in the pH range 3–6. Significantly more activity, as measured by all three methods, was found in the male in the pH range 3.4-4.0 (P < 0.01), while conversely significantly more activity was found in the female in the pH range 4.8-6.0 (P < 0.05). Ratios of the levels of FSH assayed by the three methods showed significant (P < 0.05) differences between sexes in both the original pituitary extracts and electrofocusing fractions in the pH region 4.4–6.0. The acidic fractions, when fractionated by gel filtration (Sephadex G100SF), were larger in apparent molecular size than the more alkaline fractions found in pituitary extracts from either sex. Binding of electrofocusing fractions from male pituitaries to concanavalin A showed significant (P < 0.01) differences between fractions, suggesting that the various FSH fractions may differ in their carbohydrate structure. It is concluded that the differences in apparent size and charge of FSH from male and female rat pituitaries can be attributed to the combination in different proportions of the various FSH species. However, differences in the ratio of FSH activity (in vitro bioassay, RRA and RIA) for FSH from the same pI region (pH 4.4–6.0) between sexes suggests that structural differences may also exist.     

依普拉芬和雌激素对去势后雌性大鼠骨丢失的影响

目的为了探讨依普拉芬对绝经后骨质疏松的防治作用。方法 以去势后雌性大鼠作实验模型,双能Ｘ线吸收骨密度测定（ＤＥＸＡ）及光镜图像分析方法,观察依普拉芬对去势后雌性大鼠骨丢失的作用及单独同期联合和交替使用雌激素,依普拉芬对椎骨、股肌骨密度的影响。结果 依普拉芬与去势组间骨密度有显著性差异,各用药组之间无显著性差异;光镜图像分析示去势组与依普拉芬组及其他各组间均有显著性差异。依普 分组与正常组间无显著性     

Histone acetyltransferase activity in rat hepatomas

Summary In view of various reports describing differences in histone acetylation between normal rat liver and hepatomas, the behaviour of histone acetyltransferase (EC 2.3.1.48) activity was elucidated in normal rat liver and in a spectrum of well-characterized rat hepatomas of slow, intermediate and rapid growth rates. In all tumours the acetyltransferase specific activity, expressed as nmol h^-1 mg total protein^-1, was higher than in the corresponding normal livers and the rise correlated positively with the proliferation rates of the tumors. No difference is observed if acetyltransferase activity is expressed per milligram of histone. This is explained by elevated ratios of histones and of DNA to total protein in the hepatomas compared to the ratios in normal liver. Electrophoretic analysis of [³H]acetate-labeled histones revealed similar patterns in hepatoma and normal liver. The extent of histone H4 acetylation, as indicated by the frequency distribution of non-, mono-, di-, tri-, and tetraacetylated H4-species, was found to be identical in hepatomas and normal liver. The histone protein and acetate labeling patterns were near normal in the slowly growing hepatomas.These investigations were supported in part by USPH grants CA-13526 and by an Outstanding Investigator Grant CA-42510 to G. W. awarded by the National Cancer Institute, Department of Health and Human Services, USA and by the Austrian Science Fund (Fonds zur Förderung der wissenschaftlichen Forschung, project number P5097). H. G. was a recipient of Fulbright Scholarship     

西洋参茎叶皂甙对老年大鼠血清和组织中超氧化物歧化酶的作用

实验观察了西洋参茎叶皂甙对老年大鼠血清和组织中超氧化物歧化酶(SOD)的作用。结果表明,西洋参茎叶皂甙50mg/kg能明显提高老年大鼠血清和组织中SOD的活性,与对照组相比有显著性差异(P<0.01),同样剂量对青年大鼠SOD的活性无明显作用。     

大鼠胆汁淤积性肝硬化的动态病理变化及其意义

目的：观察胆汁淤积性大鼠肝硬化形成过程中模型动态变化特点。方法：结扎大鼠胆总管制备大鼠胆汁淤积性肝硬化模型；结扎后3天、1周、2周、3用、4周、5周后杀鼠取材，观测大鼠一般状况，肝功能、肝组织羟脯氨酸（Hyp）含量测定，肝组织病理学及CK-19免疫组织化学观察。结果：与假手术组大鼠比较。模型组大鼠肝重、脾重、肝／体比、脾／体比均呈先增加后降低的动态变化；血清Alb含量持续下降，而TP含量呈先高后低的变化；血清ALT活性在结扎3天后最高，2周时最低；GGT活性及TBil含量自造模后呈持续增高；而ALP活性在2周时最高；肝组织Hyp含量从结扎后呈持续增加；结扎3天后汇管区已见胆管增生，至3周时增生逐渐加重。CK-19免疫组织化学染色观察，胆管上皮细胞第3天起开始增生，1周、2周时增生明显，3周后增生渐减。4周、5周时肝组织呈花环样改变，肝实质细胞显著减少。可见肝细胞去分化现象。结论：①胆汁淤积性大鼠肝硬化模型主要病理改变有胆汁淤积、胆管上皮细胞增生、肝细胞减少、胶原增生和沉积与新生的胆管上皮细胞关系密切。②血清ALT水平由高到低，5周末仅比假手术组稍高。AST活性一直维持在较高水平。③肝细胞的减少方式除了凋亡、坏死外，可见去分化现象。     

Uncoupler- and hypoxia-induced damage in the working rat heart and its treatment

Summary In the working rat heart we investigated heart function (aortic and coronary flow) during a normoxic, a hypoxic, and a reoxygenation phase after hypoxia. A depressed heart function was obtained by limiting oxygen supply and reducing left ventricular filling pressure (preload). After hypoxic perfusion for about 90 min, reoxygenation resulted in a 50% decrease of aortic flow. Lactate production and release increased immediately after oxygen deprivation and reached a maximum after about 35 min of hypoxia. Following reoxygenation, lactate release decreased. Lactate dehydrogenase became significant after reoxygenation.After stabilization of aortic flow at 50% in the reoxygenation phase different reagents were examined for their influence on heart performance. 1.5 mM of 2-Mercaptopropionylglycine (MPG) significantly increased aortic flow by 40%. The oxidized form of MPG (ox-MPG) at a concentration of 0.6 mM increased aortic flow by 125%. A molecular mechanism is proposed involving reorientation of the ATPase molecules at their membrane sites.This work was supported by the Deutsche Forschungsgemeinschaft     

血压平逆转肾性高血压大鼠左室重构的作用及机制

目的　探讨复方中药制剂血压平逆转二肾一夹 (2K1C)肾性高血压大鼠左室重构的作用及机制。方法　采用 2K1C法 ,建立肾性高血压大鼠 (RHR)模型 ,术后 8周将造模成功的 40只RHR随机分为 5组 ,每组 8只 ,采用放免法检测血清Ⅲ型前胶原(PCⅢ ) ,测量心肌细胞面积、周长、平均直径、长径和短径。SP免疫组化测量原癌基因C -myc和C -fos表达阳性细胞的平均光密度值。结果　①血压平有降低血压、左室重量 (LVW )、左室重量指数 (LVW /BW )、心肌细胞体积的作用 ;②血压平可降低血清PCⅢ含量 ,抑制原癌基因C -myc和C -fos的表达 ;③血压平的降压和逆转左室重构的药理作用有量效关系。结论　血压平具有逆转RHR左室重构的作用 ,其降低血压、降低血清PCⅢ含量、抑制Ⅲ型胶原合成、防治心肌纤维化及降低原癌基因C -myc和C -fos的表达、抑制心肌细胞肥大、减轻左心室肥厚 ,是其逆转2K1CRHR左室重构的部分机制。     

ACE2和ACE在自发性高血压大鼠心肌中的变化

目的:观察自发性高血压大鼠(SHR)心肌的血管紧张素转化酶(ACE)和ACE2的表达,以探讨ACE2和ACE在高血压发生发展中的变化。方法:取15只SHR,处死,分离左心室,行RT-PCR、Western blot蛋白质免疫印迹和免疫组织化学检测ACE及ACE2表达;同步取10只WKY大鼠作为正常血压对照组。结果:SHR组心肌ACE的mRNA和蛋白质表达都显著高于WKY组[(1.68±0.34)∶(0.33±0.12),P<0.05;(1.21±0.14)∶(0.71±0.11),P<0.05],而ACE2的mRNA和蛋白质表达皆明显低于WKY组[(0.50±0.15)∶(1.16±0.24),P<0.05;(0.71±0.24)∶(1.22±0.14),P<0.05)]。免疫组织化学染色显示,SHR组ACE的阳性率明显高于WKY组(87%∶50%,P<0.05),而ACE2的阳性率明显低于WKY组(27%∶70%,P<0.05)。结论:SHR心肌ACE明显升高,ACE2显著降低;SHR高血压发生发展过程中存在着ACE和ACE2表达的失衡。     

Comparison of Angiotensin II Staining in Rat Brain using Affinity Purified and Crude Antisera

The use of affinity purified ANG II antiserum as opposed to crude antiserum greatly enhanced the staining resolution in rat brain. This improved resolution was due to a complete loss of background staining and an apparent increase in specific staining that was totally blockable by preabsorption. With the purified antibody it was easily possible to visualise the finest fibres in rats not treated with colchicine. Furthermore, the improved technique permitted a clearer visualisation of an ANG II-like immunoreactive product in cell bodies. This use of affinity purified antibody should greatly facilitate the mapping of central angiotensinergic pathways.     

Levels of Immunoreactive Angiotensin II in Microdissected Nuclei from Adult wky and Sh Rat Brain

Levels of immunoreactive angiotensin II (ANG II) were measured by radioimmunoassay in microdissected nuclei from the brain of the spontaneously hypertensive rat (SHR) and its normotensive control, the Wistar Kyoto rat (WKY). The nuclei assayed included the paraventricular nucleus of the hypothalamus (PVH), locus coeruleus (LC), nucleus of the solitary tract (NTS), dorsal motor nucleus of the vagus nerve (DMN of X) and the Al region of the medulla. Sections of cerebral and cerebellar cortex were used as controls. Levels of immunoreactive ANG II ranged from 0.24 nmoles/g protein to 0.93 nmoles/g protein, with SHR brain containing significantly higher levels than WKY brain in the PVH and NTS. higher levels of immunoreactive ANG I1 than WKY brain, the difference was not significant. the A1 region between the two species, and no detectable ANG I1 immunoreactivity was found in cerebral or cerebellar cortex. Since each of the nuclei studied has been implicated in the neural control of cardiovascular function, the increased levels of immunoreactive ANG I1 in the SH rat brain nuclei indicates a possible role for ANG I 1 in the pathophysiology of hypertension in the SHR model. Although LC and DMN of X in the SHR brain contained No significant difference was found in     

Role of Long-Term Potentiation of Sympathetic Ganglia (gLTP) in Hypertension

Ganglionic long-term potentiation (gLTP) is an activity-dependent sustained increase in the synaptic efficacy of the nicotinic pathway that has been demonstrated in autonomic ganglia. Sustained enhancement in ganglionic transmission as in chronic mental stress may affect the activity of autonomic functions, including blood pressure and heart rate. An increase in sympathetic activity associated with psychosocial stress and stress-prone conditions such as obesity and aging could result in in vivo expression of gLTP leading to hypertension of a neural origin. Recent reports indicated that the prevention of the expression of gLTP in animal models of hypertension prevented or reduced high blood pressure. Although stress-induced hypertension normalizes within a few days of stress relief, prolonged mild-moderate hypertension may contribute to atherosclerotic cardiovascular diseases. The relation between hypertension and enhanced ganglionic transmission as a result of in vivo expression of gLTP is discussed in this review.     

缺氧前、后处理1-磷酸鞘氨醇对心肌细胞缺氧／复氧损伤拮抗作用的差异及相关机制

目的：探讨1-磷酸鞘氨醇（S1P）缺氧前、后处理对心肌细胞缺氧／复氧（H／R）损伤拮抗作用的差异及相关机制。方法：分离SD乳鼠（1—2d龄）心肌细胞进行体外培养。对培养的心肌细胞进行H／R处理以模拟心脏缺血／再灌注（ischemia／reperfusion,r／R）损伤。将培养的心肌细胞随机分为对照组、H／R组、H／R＋SIP缺氧前处理（H／R’pre—S1P）组及I-I／R＋SIP缺氧后处理（I-I／R＋post—S1P）组,采用四甲基偶氮唑蓝（methylthiazolyltetrazo｜ium。MTT）比色法检测心肌细胞的活力,乳酸脱氢酶（1actatedehydrogenase,LDH）检测试剂盒检测培养基中LDH的水平,caspase-3活性检测试剂盒检测心肌细胞中caspase．3的活性,Westernblot检测ATP激活的蛋白激酶（AMPK）、激活的苏氨酸激酶（Akt）、细胞外信号调节激酶1／2（ERKl／2）蛋白磷酸化水平及SIP裂解酶．1（SIPlyase1,SPLl）蛋白表达的水平。结果：与对照组相比,I-1／R组心肌细胞活力显著降低（P〈0．01）,培养基中LDH的浓度和细胞中easpase-3的活性显著增高（P〈0．01）。S1P缺氧前处理可明显增加H／R处理后心肌细胞的活力（P〈0．01）,减少LDH释放和caspase-3的活性（P〈0．01）;而I-I／R＋post—S1P组的各项指标与H／R组比较均无明显差异。Westernblot检测发现,S1P缺氧前处理可明显增高心肌细胞中AMPK、Akt和ERkl／2磷酸化的水平（P〈0．05）,而SIP缺氧后处理未激活AMPK、Akt和ERKl／2生存信号。Westernblot检测发现,缺氧处理组心肌细胞中SPLl表达的水平较对照组显著升高（P〈0．01）。结论：缺氧前用S1P处理可激活AMPK、Akt、ERKl／2生存信号,显著减少心肌细胞凋亡,增加细胞的存活率,减轻心肌细胞H／R损伤;而S1P缺氧后处理不能发挥以上保护作用,其机制可能是缺氧处理导致心肌细胞SPLl的表达上调,通过降解SIP而减弱了其介导的抗心肌细胞H／R损伤的作用。     

新生大鼠心肌细胞的原代培养及鉴定

目的：探讨新生大鼠心肌细胞原代培养的方法,培养存活率高和纯度高的心肌细胞。方法：无菌条件下取出出生1~2 d的SD大鼠心脏,用2.5 g/L胰蛋白酶和 2.0 g/L Ⅱ型胶原酶等量混合液在37℃条件下分次消化心肌组织。以差速贴壁并将时间延长至90 min纯化心肌细胞,48 h后换液。结果： 将心肌细胞24 h贴壁生长,于2~3 d心肌细胞伸出伪足,形成细胞簇,同步搏动,频率约80~130次/min,存活率为（93.9±2.8）%,纯度为（91.9±2.2）%。结论：以本实验的方法培养的心肌细胞存活率高、纯度高,是一种较为理想的原代心肌细胞培养方法。     

Tissue ascorbic acid and polyol pathway metabolism in experimental diabetes

Summary Previous studies demonstrating reduced plasma concentrations of ascorbic acid (AA) in diabetes and interactions between this vitamin and biochemical mechanisms such as synthesis of structural proteins, oxidative stress, polyol pathway and non-enzymatic glycation of proteins suggest that disturbed AA metabolism may be important in the pathogenesis of diabetic microangiopathy. However, limited information is available on the concentration of AA in tissues which develop diabetic complications. This study demonstrates reduced renal but not sciatic nerve or plasma AA concentration in two animal models of insulin-dependent diabetes mellitus, namely the STZ-diabetic rat and the spontaneously diabetic BB rat. Decreased lens AA concentration was also observed in STZ-diabetic rats. Improvement of glycaemic control by insulin treatment (albeit insufficient to achieve normoglycaemia) partially corrected lens and renal AA concentration in STZ-diabetic rats. AA treatment increased kidney and lens AA concentrations of STZ-diabetic and non-diabetic rats and corrected the abnormalities observed for untreated diabetic rats. Sciatic nerve AA concentration was not increased by AA treatment in any group. Tissue ratios of dehydroascorbic acid (DHAA)/AA, one index of oxidative stress, were not different between the diabetic and non-diabetic groups and were unaltered by AA supplementation. AA treatment of STZ-diabetic rats had no effect on elevated tissue concentrations of glucose, sorbitol and fructose or reduced myo-inositol concentration. The effect of reduced tissue AA levels in diabetes on either collagen synthesis or ability to combat increased free radical production is not known. However, correction of abnormal kidney and lens AA concentrations in experimental diabetes by AA supplementation suggests that if AA does have a role in the development or progression of the renal and ocular complications of diabetes, this treatment could be beneficial. [Diabetologia (1998) 41: 516–523] Received: 6 October 1997 and in final revised form: 15 January 1998     

Contractions to Endothelin in Normotensive and Spontaneously Hypertensive Rats: Role of Endothelium and Prostaglandins

Contractions to endothelin-1 in aortas of the spontaneously hypertensive rats (SHR) were compared with those of normotensive controls (WKY); rings with and without endothelium were studied in organ chambers. Contractions to endothelin were smaller in aortas of SHR compared to WKY, whether the endothelium was present or not. The presence of a functional endothelium reduced contractions to the peptide in both strains. Endothelium-dependent relaxations to acetylcholine and endothelium-independent relaxations to nitric oxide were observed in rings from both strains during contraction with endothelin. Indomethacin reduced the contractions to endothelin in the aorta from SHR with endothelium, but not in those without endothelium; it did not significantly affect endothelin-induced contractions in rings of WKY with or without endothelium. These experiments demonstrate that contractions of the vascular smooth muscle to endothelin are reduced in the aorta of the SHR. The basal and stimulated release of endothelium-derived relaxing factor inhibits contractions to endothelin in the aorta from both strains. The inhibitor of cyclooxygenase indomethacin does not prevent the response of the vascular smooth muscle to endothelin; however, endothelin may stimulate the release of an indomethacin-sensitive endothelium-derived contracting factor in the SHR aorta.     

Seoul Virus in Pet and Feeder Rats in The Netherlands

Seoul virus (SEOV) is a zoonotic orthohantavirus carried by rats. In humans, SEOV can cause hemorrhagic fever with renal syndrome. Recent human SEOV cases described in the USA, United Kingdom, France and the Netherlands were associated with contact with pet or feeder rats. The prevalence of SEOV in these types of rats is unknown. We collected 175 pet and feeder rats (Rattus norvegicus) from private owners, ratteries and commercial breeders/traders in the Netherlands. Lung tissue of the rats was tested using a SEOV real-time RT-qPCR and heart fluid was tested for the presence of antibodies against SEOV. In all three investigated groups, RT-qPCR-positive rats were found: in 1/29 rats from private owners (3.6%), 2/56 rats from ratteries (3.4%) and 11/90 rats from commercial breeders (12.2%). The seroprevalence was largely similar to the prevalence calculated from RT-qPCR-positive rats. The SEOV sequences found were highly similar to sequences previously found in domesticated rats in Europe. In conclusion, SEOV is spread throughout different populations of domesticated rats.