Continuous monitoring of extracellular lactate concentration by microdialysis lactography for the study of rat muscle metabolism in vivo

A method is described for the measurement and on-line monitoring of muscular extracellular lactate concentration in both anaesthetized and freely moving rats. This method is based on microdialysis sampling and lactic dehydrogenase-catalysed nicotinamide adenine dinucleotide, reduced (NADH)-fluorescence detection techniques. In vivo calibration revealed a resting extracellular lactate concentration of 1.92±0.13 mmol/l (± SEM) in the gastrocnemius muscle of adult male Wistar rats (n=6), while the average whole-blood lactate level was 0.76±0.12 mmol/l (± SEM). This measured extracellular lactate concentration was 1.73-times higher than that deduced from the arterial lactate concentration. Blocking glycolysis with iodoacetate reduced the extracellular lactate concentration to 52±6% (± SEM, n= 4) of the resting level. The extracellular lactate concentration in rat gastrocnemius muscle had increased to significantly (P0.05) different levels, 2.4±0.03 (± SEM) or 4.0±0.55 (± SEM) times the control value, 1 h after aortic clamping (n=3) or cardiac arrest (n=3), respectively. Stimulation of the sciatic nerve induced elevations of the extracellular lactate concentration in the tibialis anterior muscle which were linearly related to the recorded isometric force-time integral. We also monitored on-line the changes in extracellular lactate concentration in the tibialis anterior muscle of a swimming rat. Our results indicate that microdialysis lactate reflects also intracellular metabolism. Lactography may be a useful alternative to biopsies and nuclear magnetic resonance spectroscopy in clinical medicine and physiology for the monitoring of metabolism in vivo.     

Effects of isoflurane and halothane on the calcium ion-tension curve in rat myocardium

In order to clarify the interaction of volatile anesthetics and extracellular calcium ion on the myocardial contraction, effects of both isoflurane (1.0%) and halothane (0.5%) on the extracellular calcium ion concentration ([Ca²⁺]_O)-tension curve were studied. Increasing [Ca²⁺]_O enhanced the myocardial contraction response, and the maximal response was obtained at [Ca²⁺]_O of 3.0mM. Halothane depressed the maximal value of the tension development in response to increasing [Ca²⁺]_O, while isoflurane did not (P 0.01). The probit response of the developed tension to the changes in [Ca²⁺]_O indicated that isoflurane increased the median effective concentration (EC₅₀) of [Ca²⁺]_O significantly from 0.484 ± 0.051 (mean ± SEM) to 0.870 ± 0.056mM (P = 0.001), but halothane did not (P = 0.018). Therefore, 1.0% isoflurane was concluded to move the [Ca²⁺]_O-tension curve to the right, while a downwards shift occurred with 0.5% halothane.(Saeki S, Hirakawa M, Shimosato S: Effects of Isoflurane and Halothane on the Calcium Ion-tension Curve in Rat Myocardium. J Anesth 6: 172–175, 1992)     

Aggregated plasmalemmal vesicles and microvilli in human astrocytoma

Summary Plasmalemmal vesicles and microvilli or filopodia in human astrocytoma were examined with thin-section and freeze-fracture techniques. The plasmalemmal vesicles, although sparsely scattered in distribution, were often aggregated in a curvilinear, semicircular, or circular fashion, and the involved plasma membrane was often protruded externally like a mound.Microvilli or filopodia were cross-fractured when fracture travelled within the plasma membrane resulting in a fracture face interrupted by numerous holes of cytoplasms. The microvilli were distributed in a concentrated manner on the free suface of the cell and often closely oriented in a linear, curvilinear, or circular fashion. They varied in size, form, and length. When they were arisen from a common hillock of the plasma membrane, its fracture face was elongated, up to 0.8 in length. Fenestrae were occasionally visible in attenuated cytoplasm which surrounded peripheral vacuole in the cell.     

细胞外基质金属蛋白酶诱导因子和基质金属蛋白酶-2在喉癌中的表达

目的　了解细胞外基质金属蛋白酶诱导因子 (EMMPRIN )和基质金属蛋白酶 2 (MMP 2 )在喉癌的表达情况 ,探讨两者表达的关系以及与喉癌浸润和转移的关系。方法　采用免疫组织化学S P法对 47例喉癌和 2 2例正常喉组织中的EMMPRIN和MMP 2的表达情况进行检测。结果　EMMPRIN和MMP 2在喉癌的阳性表达率 (分别为 87.2 %和 91.5 % )明显高于正常喉组织分别为 ( 9.1%和 18.2 % ) ,EMMPRIN和MMP 2的强阳性表达与喉癌的病理分级、临床分期和淋巴结转移情况有关 ;EMM PRIN和MMP 2的表达一致率为 91.5 % ,Kappa值为 0 .614 ,两者表达具有明显的相关性。 结论　EMMPRIN和MMP 2在喉癌有阳性表达 ,表达与喉癌的临床分期和淋巴结转移有关 ,EMMPRIN与MMP 2的产生有密切的关系     

表皮生长因子受体和细胞外信号调节激酶的表达与舌鳞状细胞癌转移关系的观察

目的　了解表皮生长因子受体 (EGFR )和细胞外信号调节激酶 (ERK )在舌鳞状细胞癌中的表达 ,探讨EGFR和ERK与肿瘤增殖、转移的关系。方法　应用免疫组织化学SABC方法 ,分别对 90例舌鳞状细胞癌术后组织标本的EGFR、活化ERK 1/2和Ki 67进行检测 ,并对各因子间的表达关系进行统计分析。结果　在 90例舌鳞状细胞癌组织中 ,2 6例证实有颈部淋巴结转移 ,EGFR、活化ERK 1/2及Ki 67的阳性表达率分别为 93 .3 3 % ( 84/90 )、10 0 .0 0 % ( 90 /90 )和 10 0 .0 0 % ( 90 /90 ) ,阳性细胞分布和反应强度均以肿瘤深部边界区域最为明显 ,统计分析显示EGFR、活化ERK 1/2与肿瘤细胞增殖和肿瘤转移之间呈明显的正相关 (P <0 .0 1)。结论　EGFR、活化ERK 1/2在舌鳞状细胞癌细胞中多呈现过度表达与肿瘤的增殖、转移密切相关     

nm23-H1基因对人肺癌细胞中细胞外信号调节激酶活性的影响

目的探讨肿瘤转移抑制基因nm23-H1对人高转移大细胞肺癌细胞株L9981中细胞外信号调节激酶ERK1/2活性的影响.方法应用特异性识别总ERK1/2(p44/42 MAP kinase)和双磷酸化ERK1/2(phospho-p44/42 MAP kinase)的抗体及蛋白印迹法(Western blot),检测L9981(缺失nm23-H1基因的原代肺癌细胞株)、L9981-nm23-H1(转染了nm23-H1基因的L9981细胞株)、L9981-PLXSN(转染了空载体的L9981细胞株)中总ERK1/2和磷酸化ERK1/2的水平.磷酸化ERK1/2活性应用非放射性免疫沉淀和Western blot法以及p44/42 MAP kinase分析试剂盒予以检测.结果 L9981-nm23-H1细胞株中磷酸化ERK1/2的水平,以及ERK1/2活性均显著低于L9981细胞株和L9981-PLXSN细胞株(P<0.01),L9981和L9981-PLXSN细胞株间磷酸化ERK1/2水平和ERK1/2活性比较均无显著性差异(P＞0.05).三个细胞株间总ERK1/2水平比较均无显著性差异(P>0.05).结论 nm23-H1基因可明显靶向地抑制人高转移肺癌细胞株L9981中ERK1/2的转录表达和ERK1/2的活性.推测nm23-H1基因的作用机制可能与其抑制了MAPK/ERK信号传导通路有关.     

Simultaneous detection of tyrosine hydroxylase-immunoreactivity and vasopressin mRNA in neurons of the human paraventricular and supraoptic nucleus

The extracellular signal-regulated protein kinase-1 and -2 (ERK1 and ERK2), also referred to as the p44/42 mitogen-activated protein kinase (p44/42 MAP kinase), plays an essential role in neuronal signal transduction, but its function involved in nociceptive response has not been deeply studied yet. Here we report immunohistochemical evidence that p44/42 MAPK might be critical in nociceptive response. We found that after formalin was injected into the perioral skin of the upper lip of mice, the number of activated p44/42 MAPK-like immunoreactive neurons was significantly increased in the laminae I and II of the caudal subnucleus of the trigeminal spinal nucleus (Sp5C). The positive neurons and fibers were mostly concentrated in the middle portion of Sp5C dorsoventrally, where the afferent fibers innervating the skin of the upper lip are terminated. The reactive products were localized in perikarya, dendrites, nuclei, and diffusely in the neuropil. The present result suggests that p44/42 MAPK may be important in the transmission and modulation of noxious information in Sp5C.     

自制NECM修复兔耳廓软骨缺损的试验研究

目的本研究的目的在于评价自制同种异体天然细胞外基质(Nature Extracellular Matrix,NECM)在修复兔耳廓软骨缺损中的价值,从而在体外研究的基础上进一步证实我们采用的去污剂-酶四步法制作的NECM在组织工程学中的可行性.方法选用10只新西兰大白兔,于其双耳廓制造1.0×.0cm大小的软骨缺损后,分别作以下研究:①灰兔NECM修复兔耳廓缺损.②灰兔NECM复合软骨膜修复兔耳廓缺损;③不植任何材料的空白对照.术后4、6、12、24周取材并行组织学检查.结果NECM植入后4、6周有轻重不一的炎症反应,第12周炎症反应消失,NECM周边无包裹现象.第12周时NECM复合软骨膜组有软骨膜细胞长入NECM,此时的软骨膜细胞多处于增殖期,24周时软骨膜细胞继续增殖分化细胞逐渐长入NECM深部,且部分软骨膜细胞发育成熟.单纯NECM修复组,第6周出现纤维结缔组织长入NECM,12、24周纤维结缔组织逐渐长入NECM深部,并逐渐取代NECM.结论①NECM可诱导软骨膜细胞增殖分化生长,修复软骨缺损:②NECM具有较好的组织亲和性和相容性;③软骨膜细胞可以作为NECM再生软骨的种子细胞的来源;④软骨膜可以阻止纤维结缔组织侵入修复区NECM.     

p-ERK在早孕绒毛组织中的表达及意义

目的:研究人早孕绒毛组织中磷酸化的细胞外信号调节蛋白激酶(p-ERK)的表达水平,探讨流产及其有关生殖过程发生的分子机制。方法:采用免疫组织化学、图像分析方法检测30例正常早孕绒毛组织(正常早孕组)和30例自然流产的早孕绒毛组织(自然流产组)中p-ERK的表达水平。结果:人早孕绒毛细胞滋养细胞、合体滋养细胞均有p-ERK的表达,自然流产组中p-ERK蛋白表达面积及强度均明显低于正常早孕组,两者差异有显著性意义(P<0.05)。结论:ERK/MAPK(丝裂原活化蛋白激酶)通路可能是人早孕绒毛滋养细胞增殖、分化及侵入过程中的主要信号转导途径之一。     

Rab10蛋白及其在肿瘤中的研究进展

Rab10蛋白作为Rab鸟苷三磷酸酶家族成员之一,不仅参与细胞内囊泡的形成、转运、锚定和融合过程,同时也影响肿瘤的发生发展.通过对Rab10在细胞内囊泡运输和肿瘤中的机制研究,可能为抗肿瘤治疗提供潜在的靶点和新思路.