稳定性核素测定大鼠小肠蛋白质合成

目的：建立稳定性核素（[L-^15N]亮氨酸）测定大鼠小肠蛋白质合成率的方法。方法：分别测定静脉注射相同剂量[L-^15N]亮氨酸不同时相的大鼠小肠^15N丰度及不同剂量[L-^15N]亮氨酸同一时相的大鼠小肠^15N丰度。结果：大鼠小肠游离氨基酸池中^15N核素丰度在注射后0．5h内呈线性上升并达高峰，维持4h后缓慢下降，小肠蛋白质中的^15N丰度0．5h至12h基本维持不变；随着注射剂量的增加，大鼠小肠蛋白质分数合成率（FSR）亦增加，当[L-^15N]亮氨酸剂量在1．0mmol／kg以上，FSR并不随施加[L15N]亮氨酸剂量的加大而增加。结论：在进行大鼠小肠蛋白质合成率测定时，一次性静脉注射的测量最佳时限为0．5h，剂量为1．0mmol／kg。     

二甲亚砜对人表皮的核酸和蛋白质合成的影响

用体外培养的人的伪表皮作为模型，进行药物毒理学作用的研究，观察了二甲亚砜（ＤＭＳＯ）在不同浓度和不同接触时间条件下，对人的伪表皮细胞脱氧核糖核酸（ＤＮＡ）、核糖核酸（ＲＮＡ）和蛋白质合成的影响：随着接触时间的延长，ＤＮＡ、ＲＮＡ和蛋白质合成均受抑制。低浓度条件下（１％），ＤＮＡ、ＲＮＡ和蛋白质合成增加；在１５～５０％浓度下，ＤＮＡ和蛋白质合成抑制，而ＲＮＡ合成仍增加；在高浓度条件下（７０％～１００％），ＤＮＡ、ＲＮＡ和蛋白质合成均明显抑制。     

重组O-GLcNAc糖基转移酶在昆虫细胞中的表达和纯化

蛋白质的 O- Glc NAc糖基化修饰是一种细胞核蛋白与细胞浆蛋白的蛋白质翻译后修饰。不同于膜蛋白和分泌蛋白的糖基化修饰 ,与蛋白质磷酸化修饰相似。催化蛋白质 O- Glc NAc糖基转移酶 ( OGT)已被克隆。用Hi5昆虫细胞系统表达并纯化了具有活性的重组 OGT。在 Hi5昆虫细胞中表达的鼠肝 OGT带有一 His 6标记片段。经镍离子螯合柱纯化后 ,其比活性达到 0 .88nmol· min- 1·m g- 1 OGT。因此本研究为进一步研究蛋白 O- Glc NAc糖基化修饰提供重要资源     

Decreased expression of DMPK: correlation with CTG repeat expansion and fibre type composition in myotonic dystrophy type 1

Abstract Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by a trinucleotide repeatexpansion, cytosine-thymine-guanine (CTG)_n, in the 3′ untranslated region of a gene encoding the myotonic dystrophy protein kinase (DMPK). To correlate CTG expansion and protein expression, we studied muscle specimens from 16 adult DM1 patients using three anti-DMPK antibodies for immunoblotting. We estimated the amount of the full-length DMPK (85 kDa) in muscle biopsies from normal controls and from DM1 patients carrying different (CTG)_n expansions. We found that DMPK concentration was decreased to about 50% in DM patients’ muscles; the protein decrease did not seem correlated with the CTG repeat length. However, the fibre type composition in skeletal muscle seemed somehow to affect DMPK decrease, as the lowest level of the enzyme was found in patients with the lowest content of type 1 fibre.     

Effects of chelating agents on the rheological property of cervical mucus

As an ongoing effort to elucidate the mechanisms involved in the calcium-dependent fertility regulation process, the viscoelastic properties of the mucus obtained from lamb cervix and human semen, as well as their water and total protein contents after exposure to EDTA, a chelating agent, or Nonoxynol-9 (N-9), a spermicidal agent, were examined. The viscosity was measured using a Cone Plate Digital Viscometer, while the water and total protein contents were determined by the lyophilization process and the Lowry method, respectively. The significant changes in the rheological properties of mucus, such as its viscosity and the water content, upon exposure to EDTA were demonstrated. The viscosity of cervical mucus and human semen were significantly increased by EDTA treatment (as compared to the controls): lamb cervical mucus (2.9 ± 0.3 vs. 2.2 ± 0.3 cps) and human semen (5.0 ± 0.3 vs. 4.3 ± 0.3 cps), respectively. The hydration rate was decreased by EDTA treatment as compared with the control (93.6 ± 0.7 vs. 96.8 ± 0.8%). Among tested samples, the reduction in the percentage of sperm penetration through the cervical mucus was the highest in the mucus containing EDTA, which had the lowest water content (93.6 ± 0.7%), indicating that there is a positive relationship between the hydration rate of the cervical mucus and its ability to permit the penetration of spermatozoa. This result indicates that spermicidal activity exerted by high concentrations of EDTA is in part due to its effect on the rheological properties of cervical mucus or semen.     

血浆蛋白C、蛋白S与脑梗死的相关性研究

目的研究血浆蛋白C、蛋白S与脑梗死发病的关系。方法对64例脑梗死患者及15例正常对照组进行血浆蛋白C(PC)、蛋白S(PS)检测,并分析其与脑梗死严重程度、年龄及其它脑梗死危险因素之间的关系。结果实验组血浆PC浓度(4.97±1.82μg/ml)与对照组血浆PC浓度(4.74±1.95μg/ml)之间差别无统计学意义;首发组血浆PC浓度(5.28±1.85μg/ml)与复发组血浆PC浓度(4.03±1.40μg/ml)之间差别有统计学意义(P=0.016);实验组血浆PS浓度(7.47±3.87μg/ml)与对照组血浆PS浓度(12.06±3.99μg/ml)之间差别有统计学意义,中老年组血浆PS浓度(6.58±3.33μg/ml)与青年组血浆PS浓度(9.28±4.33μg/ml)之间差别有统计学意义。结论PC降低是复发性脑梗死的危险因素之一;游离PS降低是脑梗死的危险因素;PS水平的降低导致PC功能的降低,进而凝血功能障碍,导致脑梗死的发生。     

Effect of dietary protein on Masheri-induced drug metabolising enzymes

The modulation of drug metabolising enzymes by Masheri extract (ME) and Benzo(a)Pyrene [B(a)P] was studied in male Sprague Dawley rats fed different dietary protein levels. Two groups of 21 days old male Sprague Dawley rats were put on a high protein diet (SHP) with 20% Casein, and a low protein diet (SLP) with 3% Casein semisynthetic based diets for 12 weeks. The SLP fed animals showed lower basal levels of the Phase I activating enzymes viz. Cytochrome P450, Benzo(a)Pyrene hydroxylase, Benzphetamine demethylase and Phase II glutathione detoxification system viz. Glutathione (GSH) and Glutathione-S-transferase. ME and B(a)P treatment significantly depleted the glutathione detoxification system in the SLP group whereas an opposite effect was observed in the SHP group. Interstingly, ME and B(a)P treated rats in the SLP group showed a higher percent increase in the hepatic and pulmonary Phase I enzyme activities than those observed in the treated ME/B(a)P treated SHP rats. Furthermore, both ME and B(a)P significantly decreased the hepatic pool of vitamin A while a concomittant increase in that of vitamin C was observed.     

胃肠道肿瘤病人围手术期细胞因子及蛋白质代谢的变化

目的 :探讨胃肠道肿瘤病人手术后肿瘤坏死因子 α (TNF α)、白介素 6 (IL 6 )、白介素 10 (IL 10 )的变化以及与蛋白质代谢的关系。　方法 :用酶联免疫法 (ELISA)检测 19例胃肠道肿瘤根治术病人术前和术后 1、3、5天血清TNF α、IL 6和IL 10水平 ,同时检测蛋白质分解代谢相关指标、2 4h尿中尿素和肌酐排泄量。　结果 :胃肠道肿瘤根治术后病人TNF α呈下降趋势 ,术后第 1天较术前明显下降 (P <0 .0 5 )。IL 6和IL 10术后升高 (P <0 .0 1) ,尤以术后第 1天升高明显。术后 2 4h尿中尿素和肌酐排泄量明显升高。　结论 :胃肠道肿瘤根治术后病人IL 6和IL 10的升高支持手术应激导致的细胞因子释放变化 ,但TNF α呈下降趋势 ,可能与胃肠道肿瘤病人术前TNF α的高表达有关。术后蛋白质分解代谢增加 ,可能与细胞因子IL 6和IL 10的升高有关。     

Fentanyl and the interleukin-6 response to surgery

It has been suggested that large doses of opioids may suppress the interleukin-6 response to surgery. We examined the effects of the supplementation of inhalational anaesthesia with either 3 or 15 μg.kg⁻¹ fentanyl on the circulating interleukin-6, interleukin-8, C-reactive protein, cortisol and glucose concentrations in 16 patients undergoing pelvic surgery. In both groups, surgery evoked the expected glucose, cortisol and interleukin-6 response but no increase in interleukin-8 was detected. There were no significant differences between the two groups. We conclude that the supplementation of inhalational anaesthesia with conventional doses of opioids does not modify the cytokine response to surgery.