大白鼠心室肌细胞ClC-2型氯通道的特性

目的研究在生理及病理条件下C lC-2型氯通道(简称C lC-2)的特性。方法以酶解法分离大白鼠心室肌细胞,先后用正常、改变渗透压以及不同的pH值的灌流液灌流,并采用膜片钳全细胞记录法观察心室肌细胞C lC-2通道的活性变化。结果①正常心室肌细胞的C lC-2通道具有电压依赖性。它在细胞膜超极化(-40~-100 mV)时激活,由C l-介导的一种内向整流电流(IC I,ir)。低渗时细胞膨胀会加速激活,增加电流强度。高渗时反之。它可以被9-蒽甲酸(9-AC)所阻断,但对乙拌磷1,2-二苯乙烯衍生物SITS不敏感。②当pH值从7.4升高到8.0时,IC l,ir强度减小;当pH值从7.4下降到6.8时IC l,ir强度明显增加。在pH值为5.5的时候,电流几乎为零。结论C lC-2通道介导的IC l,ir,在超极化、低渗、细胞肿胀及酸性环境下其电流强度明显增加。     

胸水结核抗体对结核性胸膜炎的诊断意义

目的 了解结核性胸膜炎的诊断意义。方法 检查205例胸水的病因分析。结果 胸水结核抗体对结核性胸膜炎阳性率最高83.1%。结论 胸水结核抗体对鉴别结核性胸膜炎有较高实用价值。     

Galanin antisense oligonucleotides reduce galanin levels in dorsal root ganglia and induce autotomy in rats after axotomy.

Antisense (AS) oligonucleotides (ONs) to galanin (GAL) were applied to the proximal end of a transected sciatic nerve, allowing their cellular uptake and transport into injured axons. GAL expression in dorsal root ganglia and self-mutilation behavior (autotomy) were then studied. AS-ONs with phosphorothioate or allyl modifications significantly suppressed the axotomy-induced increase in GAL levels, as demonstrated by immunohistochemistry and exaggerated autotomy behavior, whereas no significant effect on GAL mRNA levels could be demonstrated with in situ hybridization. Allyl-ONs were more effective than phosphorothioate-ONs. An AS-ON with three base mismatches did not induce any of the above effects. These results support the view that the inhibition of axotomy-induced GAL up-regulation is related to autotomy.     

N糖基化对SMMC7721移植瘤生长及FAS,NM23,ICAM-1表达的调控

目的观察N糖基化抑制剂swainsonine对人肝癌细胞株SMMC7721体内生长的影响及探讨其可能的作用机制.方法将SMMC7721接种于裸鼠,对比研究饮用含1 mg/Lswainsonine饮用水的荷瘤裸鼠和对照组裸鼠的生存期及肿瘤大小指数,运用免疫组织化学的方法观察两组瘤组织标本的FAS,NM23,ICAM-1的表达情况.结果 swainsonine能延长实验组荷瘤裸鼠的生存期,抑制SMMC7721在荷瘤小鼠上的生长,其肿瘤生长抑制率为36%.FAS,NM23,ICAM-1的表达在实验组明显增强.结论 N糖基化抑制剂swainsonine能抑制人肝癌细胞株SMMC7721在裸鼠体内的生长,其对肿瘤组织fas,nm23 ICAM-1表达的调控可能与其作用机制有关.     

3alpha-Hydroxysteroid dehydrogenase type III deficiency: a novel mechanism for hirsutism

CONTEXT: Dihydrotestosterone (DHT), the primary active androgen in peripheral target tissues, is metabolized by 3alpha-hydroxysteroid dehydrogenase type III (3alpha-HSD), encoded by the AKR1C2 gene, forming 5alpha-androstane-3alpha,17beta-diol (3alpha-diol). 3alpha-HSD may play a role in the pathogenesis of hirsutism. OBJECTIVES: Our objective was to evaluate the role of 3alpha-HSD in hirsutism by comparing 1) tissue levels of active androgens, 2) relative gene expression of AKR1C2, and 3) activity of 3alpha-HSD in genital skin from normal and hirsute women. DESIGN: Genital skin was obtained from normal and hirsute women. After homogenization, testosterone (T) and DHT levels were quantified by conventional RIA. From isolated RNA, relative expression of AKR1C2 was determined by real-time PCR. In addition, minced genital skin was incubated with [(3)H]DHT, and the product, [(3)H]3alpha-diol, was quantified by radio-HPLC. SETTING: The study took place at an inner-city hospital. Patients: Patients included women undergoing posterior colporrhaphy. MAIN OUTCOME MEASURES: We assessed 1) tissue levels of T, DHT, and 3alpha-diol; 2) relative expression of AKR1C2; and 3) conversion ratio of [(3)H]3alpha-diol to [(3)H]DHT. Results: In genital skin, tissue DHT and T concentrations in hirsute women were 1.90-fold and 1.84-fold higher than in normal women (P =0 .002 and 0.03), and relative expression of AKR1C2 mRNA was reduced approximately 7-fold (P = 0.04). Genital skin from hirsute women showed less metabolism of [(3)H]DHT to [(3)H]3alpha-diol (conversion ratio, 0.24 +/- 0.19 vs. 0.85 +/- 0.55, P = 0.01). CONCLUSIONS: In genital skin of hirsute women, reduced AKR1C2 gene expression and 3alpha-HSD activity results in decreased DHT metabolism and elevated tissue levels of DHT. Diminished DHT metabolism may play an important role in the pathogenesis of hirsutism.     

Microsatellite instability and novel mismatch repair gene mutations in northern Chinese population with Hereditary non‐polyposis colorectal cancer

OBJECTIVE: Hereditary non‐polyposis colorectal cancer (HNPCC) syndrome is the most common cause of hereditary colorectal cancer with an early age of onset. Microsatellite instability (MSI) and germline mutation in one of the DNA mismatch repair (MMR) genes are found in the majority of HNPCC families and provide an opportunity for genetic diagnosis and prophylactic screening. The MMR gene mutation spectrum may vary across different populations and be influenced by founder mutations that prevail in specific ethnic groups. China is a big and ancient nation with enormous genetic diversity, which is especially notable between the northern and southern Chinese populations. A MMR gene mutation database for the southern Chinese population based in Hong Kong has been previously established. This study compares the MMR gene mutation spectrum and the MSI of HNPCC between the northern and southern Chinese populations. METHODS: Twenty‐five HNPCC families from northern China were systematically analyzed. The MSI analysis was performed using five loci in the USA National Cancer Institute (NCI) panel (D2S123, D5S346, BAT‐25, BAT‐26 and BAT‐40) by PCR from the tumor and normal tissue. MSH2, MSH6 and MLH1 were performed using immunohistochemical staining. Two founder mutations of MSH2 and MLH1 were examined by PCR base analyses using primers flanking the two deletion sites (c.1452_1455delAATG in MSH2 and 1.8 kb deletion involving exon 11 of MLH1) . RESULTS: Of the 25 families collected, 19 met Bethesda guideline (BG) 1 and six met BG3. Twenty‐two (15.7%) were extra‐colonic cancers with gastric cancer (in seven patients) being the most common cancer type. Of the 25 tumors analyzed, 21 (84%) were high level microsatellite instability (MSI‐H) and four (16%) were microsatellite stable (MSS). Eighteen (86%) of the 21 MSI‐H tumors showed loss of either the MLH1 or the MSH2 protein. Three MSI‐H tumors and all four MSS tumors showed no loss of expression of the three MMR proteins. Out of the 21 patients with MSI‐H tumors, 12 (57%) showed pathogenic germline mutations in either MLH1 (n = 8) or MSH2 (n = 4). Overall, three novel mutations (in patients H22, H17 and H29) have been identified. One of them, c.503_4insA, caused a frameshift mutation in the MLH1 gene. The other two were found in the MSH2 gene, including a frameshift (c.899_890insAT) and a splice junction (IVS7‐1G→A, SA of Exon 8) mutation. CONCLUSIONS: The results suggest a distinctly different mutation spectrum of MMR genes between northern and southern Chinese populations and call for a systematic, nationwide study to facilitate the design of a MMR gene mutation detection strategy tailored for individual populations in China.     

再灌注对急性心肌梗死左室舒张与收缩功能影响的实验研究

本文用急性心肌梗死（ＡＭＩ）犬模型对左室舒张与收缩功能及再灌注后的变化特点进行了观察。结果发现，ＡＭＩ后２、３和７２小时左室舒张与收缩功能均明显下降，在ＡＭＩ后７２小时再灌注组左室舒张与收缩功能明显优于未再灌注组（Ｐ＜０．０５和Ｐ＜０．０１）。     

Sodium channel mutations in paramyotonia congenita exhibit similar biophysical phenotypes in vitro.

Mutations in the skeletal muscle voltage-gated Na+ channel alpha-subunit have been found in patients with two distinct hereditary disorders of sarcolemmal excitation: hyperkalemic periodic paralysis (HYPP) and paramyotonia congenita (PC). Six of these mutations have been functionally expressed in a heterologous cell line (tsA201 cells) using the recombinant human skeletal muscle Na+ channel alpha-subunit cDNA hSkM1. PC mutants from diverse locations in this subunit (T1313M, L1433R, R1448H, R1448C, A1156T) all exhibit a similar disturbance in channel inactivation characterized by reduced macroscopic rate, accelerated recovery, and altered voltage dependence. PC mutants had no significant abnormality in activation. In contrast, one HYPP mutation studied (T704M) has a normal inactivation rate but exhibits shifts in the midpoints of steady-state activation and inactivation along the voltage axis. These findings help to explain the phenotypic differences between HYPP and PC at the molecular and biophysical level and contribute to our understanding of Na+ channel structure and function.     

萃取光度法测定水中氯硝柳胺含量的研究

目的实验室条件下,采用萃取光度法测定水中氯硝柳胺含量。方法采用1:9乙酸丁酯-石油醚混合溶剂萃取,再用NaOH反萃取有机相中的氯硝柳胺,用双波长光度法测定。结果在实验室条件下,氯硝柳胺的提取率达93％。测定的线性范围为0-4g／m3,检出限为0．042 7 g／m3, 方法的表观摩尔吸光系数为1．26×105L／(mol·cm)。结论萃取光度法能用于水样中氯硝柳胺含量的现场检测。     

Aspirin and clopidogrel treatment impair nitric oxide biosynthesis by platelets

Aspirin and clopidogrel are used therapeutically for their anti-platelet effects. We examined the effects of aspirin and clopidogrel on basal and β-adrenoceptor (β-AR)-mediated platelet nitric oxide (NO) synthesis in healthy subjects and patients with coronary heart disease (CHD). Healthy subjects (n = 19) were randomized in a double-blind cross-over manner to receive aspirin or clopidogrel, each at 75 mg daily, for 14 days. Patients (n = 17) of similar age with CHD, taking aspirin, were randomized double-blind to either continue on aspirin 75 mg daily or to receive clopidogrel 75 mg daily for 14 days. NO synthase (NOS) activity was measured from l-[³H]arginine to l-[³H]citrulline conversion, and cGMP was determined by radioimmunoassay, in platelets basally and following incubation with isoproterenol or albuterol (each at 10⁻⁵ mol/L). In healthy subjects, aspirin did not affect basal NOS activity or cGMP in platelets, but suppressed the normal increase in both by isoproterenol and albuterol. Clopidogrel suppressed platelet NOS activity and cGMP both basally and in response to β-AR agonists. In platelets from CHD patients, clopidogrel suppressed basal and β-AR-stimulated NOS activity and cGMP as compared with aspirin. Platelet NOS activity and cGMP were lower in CHD subjects pre-randomization compared with healthy subjects both pre-randomization and post-aspirin. We conclude that chronic aspirin treatment suppresses β-AR-stimulated but not basal platelet NO synthesis, as previously described, whereas chronic clopidogrel treatment suppresses both, with resultant functional consequences. Moreover, CHD may itself be associated with decreased platelet NO biosynthesis.