Compensatory adaptation of the heart to chronic rate overload: increase in calcium transport ATPase activity of myocardial sarcoplasmic reticulum

This study was undertaken to test the hypothesis that a compensatory response of the heart to a chronic and continuous, metabolic and heart rate overload was an increase in the calcium sequestering activity of the myocardial sarcoplasmic reticulum. Calcium sequestering activity was estimated by determination of the calcium-dependent ATPase (Ca2+-ATPase) activity of isolated microsomes. Chronic rate overload was modelled by comparing: dysthyroid and control rats; control swine and swine with implanted cardiac pacemakers set at 180 beats/min; and different species of mammals with widely different heart rates. The myocardial sarcoplasmic reticulum Ca2+-ATPase pump activity was significantly increased by 39% for hyperthyroid rats compared to control rats and by 87% for control rats compared to thyroidectomized rats; by 63% for paced swine compared to control swine; and by 43% for rats compared to guinea pigs, by 140% for guinea pigs compared to dogs and by 120% for dogs compared to cows. These data indicate that calcium sequestering activity of myocardial sarcoplasmic reticulum increases in equivalent proportion to the chronotropic demand and that heart rate is a hemodynamic correlate of the sarcoplasmic reticulum Ca2+-ATPase activity.     

蛛网膜下腔注射神经降压素对大鼠血压和心率的影响

本文研究了蛛网膜下腔注射神经降压素（ｎｅｕｒｏｔｅｎｓｉｎ，ＮＴ）对大鼠血压和心率的影响，结果表明：注射ＮＴ后血压立即下降，继而有所回升，但不及正常水平，然后再次降低，持续６０ｍｉｎ；心率无明显改变。Ｈ１受体阻断剂苯海拉明能部分阻断ＮＴ的降血压效应，Ｈ２受体阻断剂甲氰咪胍无翻转作用。注射组胺释放剂Ｃｏｍｐｏｕｎｄ４８／８０使血压下降，待血压恢复正常水平后，再注射ＮＴ，其降压效应减弱。结果提示：蛛网     

Multiple sclerosis: myelin basic protein induced mRNA expression of proinflammatory cytokines in mononuclear cells is suppressed by interferon-β 1b in vitro

Beta-interferon (IFN-β) is a promising treatment in multiple sclerosis (MS), reducing the exacerbation rate and MRI lesion burden, as well as the disease progression in relapsing-remitting MS. IFN-β was originally defined by its antiviral effects, but the interest has recently been focused on its immunomodulatory properties. Myelin basic protein (MBP) is one of several autoantigens considered to be the target for autoaggressive immune responses, which eventually might lead to the development of MS. To study in-vitro effects of IFN-β1b on MBP induced cytokine expression, mRNA for the Th1 cytokines IFN-γ and TNF-α, the Th2 related IL-4 and IL-6, the cytolytic perforin and the immune response downregulating TGF-β was measured with in situ hybridization after culture of blood mononuclear cells (MNC) in the presence and absence of MBP. Numbers of cells expressing IFN-γ, TNF-α, perforin and IL-4 mRNA were significantly suppressed after culture with 10 U/ml IFN-β1b. No such effect was seen on MBP induced IL-6 or TGF-β mRNA expression. These observations suggest that one of the major effects of IFN-β1b is the induction of a shift in the cytokine mRNA profile towards a more immunosuppressive pattern. In parallel in vitro tests, the control substance dexametasone (40 μg/ml) reduced the numbers of cells expressing mRNA for all cytokines under study with the exception of TGF-β, to an extent equal to or even more pronounced than IFN-β1b.     

病理性损伤因素对肾小管上皮细胞表型转化的影响

目的 :观察低血清、高糖、高蛋白刺激下肾小管上皮细胞向间叶性细胞的表型转化 ,探讨损伤的肾小管上皮细胞在肾小管间质纤维化中的作用。方法 :以体外培养的人近端肾小管上皮细胞为对象 ,分别用含低血清(0 .2mol·L-1小牛血清 )、高葡萄糖 (4.5 g·L-1)、高白蛋白 (15 g·L-1)的培养液培养 7d ,透射电镜检测细胞形态变化 ;免疫组化和Westernblot检测细胞表型改变 ,包括CK、Vimentin、α SMA、Ⅰ和Ⅲ型胶原 ,原位杂交检测Ⅰ型胶原mRNA表达 ,同时检测细胞TGFβ1蛋白表达。 结果 :低血清、高糖、高蛋白直接刺激下 ,肾小管上皮细胞出现明显形态学改变 ,包括细胞变为长梭形 ;透射电镜下细胞内线粒体明显减少 ,粗面内质网明显增加 ,并出现actin样微丝。免疫组化染色和Westernblot显示CK表达明显减弱 ,Vimentin、Ⅰ、Ⅲ型胶原、α SMA和TGFβ1表达增强。原位杂交显示Ⅰ型胶原mRNA表达增强。结论 :低血清、高糖、高蛋白可直接引起人近端肾小管上皮细胞TGFβ1表达增加 ,并发生向间叶性细胞的表型转化     

Elevated extracellular potassium is associated with a reduced extracellular space in rat neural lobe in vitro

Summary Increased neural activity of neurosecretory cells is accompanied by large increases in extracellular K⁺. The possibility that elevations of this ion might involve fluid redistribution and thus affect the size of the extracellular space and the relationship between pituicytes and axons in the rat neural lobe was explored using rapid freezing and freeze-substitution. Neural lobes were incubated for 15 min before freezing either in a normal medium or one containing a 10 mM increase in KCl (high KCl), a 10 mM increase in KCl balanced by an equimolar reduction in NaCl (high KCl-low NaCl), or only a 10 mM reduction in NaCl (low NaCl). A quantitative assessment of the region of good fixation was made to determine the relative fractions occupied by axons, pituicytes and the extracellular space near the neurohaemal contact zone. In addition, the percentage of basal lamina contacted by pituicytes and axons was calculated, as was the degree of enclosure of axons by pituicytes.In neural lobes incubated in normal medium, the extracellular space accounted for approximately 30% of the cross-sectional area of the neuropil and could be divided into two domains: an extended perivascular space (28–29% of total area); and a narrow (approximately 24 nm; approximately 1% of total) space between closely apposed neurosecretory processes or between these processes and pituicytes. Pituicytes occupied almost 60% of the basal lamina at the neurohaemal contact zone, while axons occupied approximately 20%. Neural lobes incubated in either the high KCl solution, or in the high KCl-low NaCl solution, exhibited a significantly reduced extracellular space, to about 20% of the total area, or a reduction from controls of about one-third. The reduction was complemented by an increased area occupied by axons plus pituicytes. In the high KCl group, the contribution of the narrow spaces (22–24 nm) between apposed processes to the total extracellular space was greatly increased. The group exposed to low NaCl showed high variability in the size of extracellular space, and was thus not significantly different from any other group. No changes in any group were observed in the enclosure of axons by pituicytes, or in the relative amounts of axon and pituicyte apposition to the basal lamina.The subsequent buffering of K⁺ and other ions during periods of increased neuronal activity may be affected by changes in the extracellular space, thereby influencing stimulus-secretion coupling. A shrinkage of the extracellular space and the relative increase in the narrow spaces between processes initiated by elevated K⁺ could also alter the diffusion properties of the neural lobe.     

自体骨髓多次注射治疗家兔骨缺损的实验研究

目的：观察骨髓多次注射的成骨性能。方法：利用家兔实验性骨缺损模型，通过大体、组织学观察，生物力学测定，评价骨髓不同移植次数促进骨缺损愈合的情况。结果：骨髓单次移植能够促进骨缺损的愈合，然而，骨髓二次移植组骨折愈合程度明显优于骨髓单次移植组，但骨髓三次移植组与骨髓二次移植组骨折愈合无明显差异。结论：在骨折愈合早期增加骨髓移植次数，能明显增强骨髓的成骨能力，加快骨折愈合     

授权影印西文书的特点及其机读目录的著录方法

对授权影印书的特点进行了分析，并对其机读目录著录方法和需要注意的问题进行了论述。     

305例老年死亡病例医院感染回顾性调查

本文结果表明,305例老年死亡病例医院感染的发病率为33.8％。感染最多部位为肺部(66.9％),其次为尿路感染(19.4％)。高龄患者,侵袭性操作、多种抗生素联合应用,激素疗法等是诱发医院感染的危险因素。58.8％的病原菌为革兰氏阴性杆菌,37.2％为真菌。31株病原菌药敏结果显示耐药率为33.3％。本文指出合理应用抗生素是预防医院感染的重要措施之一。     

逆行灌注心脏不停跳心肌保护的实验研究

目的：探讨逆行灌注心脏不停跳心肌保护的效果。方法：中国大白兔32只随机分为4组，每组8只，A组（对照组），B组（心脏不停跳组，血温34℃），C组（温血心脏麻痹液组，血温34℃），D组（冷血心脏麻痹液组，血温4℃）。采用离体兔心左室做功模型，经冠状静脉窦逆行灌注稀释血液或血停搏液60min。比较观察心功能、冠脉排出液心肌酶谱、心肌组织乳酸、心肌细胞内游离钙浓度、心肌细胞膜ATP酶活性、心肌细胞膜脂质过氧化产物丙二醛含量的变化。结果：B组心功能恢复、心肌细胞膜ATP酶活性显著优于C组和D组，C组优于D组；B组心肌酶漏出、乳酸生成量、心肌细胞内游离钙浓度、心肌细胞膜丙二醛（MDA）含量低于C组和D组，C组低于D组。结论：常温氧合血逆灌心脏不停跳良好的心肌保护效果与其减轻自由基损伤，较好地保持细胞内外Ca^2 平衡，减轻细胞内钙超载，保护细胞膜酶功能有关。