慢性吗啡处理对大鼠嘌呤核苷酸补救合成酶基因表达的影响

对一些原代细胞及细胞系的体外研究表明 ,吗啡或其它阿片类大多抑制脑来源细胞的ＤＮＡ或ＲＮＡ合成 ,而促进脑外来源细胞的ＤＮＡ或ＲＮＡ合成 ,有关机制还不清楚。吗啡或其它阿片类是否通过干扰核苷酸代谢相关酶的基因表达影响核苷酸代谢 ,进而影响核酸代谢 ?国内外尚未见此类研究报道。中枢神经系统调控阿片类产生的躯体依赖与精神依赖。脑组织中只能进行嘌呤核苷酸的补救合成。本文采用反转录 -聚合酶链反应ＲＴ ＰＣＲ检测吗啡依赖大鼠部分组织中嘌呤核苷酸补救合成途径的两个关键酶次黄嘌呤 -鸟嘌呤磷酸核糖转移酶ＨＧＰＲＴ和腺苷激…     

Hypoxanthine-guanine phosphoribosyltransferase gene analysis for Japanese patients with Lesch-Nyhan syndrome

The Lesch-Nyhan syndrome results as a consequence of a severe deficiency of functional activity of purine salvage enzyme, hypoxanthine phosphoribosyltransferase (HPRT). We performed Southern blot analysis for five patients and their families using full length cDNA of the HPRT gene as a probe. Pst I digested Southern blot analysis revealed a large deletion that included exon 2 in patient 3. The size of this deletion was about 4.4 Kb. The mother of this patient had the same mutated allele and a normal one (heterozygote). This type of mutation from a Lesch-Nyhan syndrome patient has not been previously reported. The restriction fragment length polymorphism (RFLP) pattern was analyzed by Bam HI digested Southern blot analysis for one family who had no major gene abnormality. We determined from this analysis that the sister of the patient was a Lesch-Nyhan syndrome carrier and the fetus (brother) was normal for HPRT activity. This study shows RFLP analysis is still useful for carrier detection and prenatal diagnosis of Lesch-Nyhan syndrome.     

Circumvention of 5-Fluorouracil Resistance in Human Stomach Cancer Cells by Uracil Phosphoribosyltransferase Gene Transduction

A human stomach cancer cell line with acquired resistance to 5-fluorouracil (5-FU), NUGC-3/5FU/L, has been found to possess reduced ability to convert 5-FU into active metabolites. We attempted in vitro gene therapy for this 5-FU-resistant cell line. NUGC-3 and NUGC-3/5FU/L cells were infected with recombinant adenovirus (Ad) containing Escherichia coli uracil phosphoribosyltransferase ( UPRT ) gene driven by CAG promoter (CA), AdCA-UPRT, and changes in their 5-FU metabolism and sensitivity were investigated. Activities of orotate phosphoribosyltransferase increased from 10.2 and 1.56 (nmol/mg protein/30 min) in the uninfected cells of NUGC-3 and NUGC-3/5FU/L to 216 and 237, respectively, after the transfection of UPRT gene. The 5-FU nucleotide level in the acid-insoluble fraction increased from 7.32 to 15.9 (pmol/mg protein) in NUGC-3 cells on infection with AdCA-UPRT, and in NUGC-3/5FU/L cells it increased from 1.91 to 21.4. The 50% growth-inhibition concentration (IC50) was 12.7 μmol/liter for NUGC-3 and much higher than 100 μmol/liter for NUGC-3/5FU/L, indicating over 8-fold resistance. NUGC-3/5FU/L transfected with the UPRT gene showed very high sensitivity to 5-FU with an IC₅₀ of 3.2 μmol/liter. The high resistance in this metabolic activation-deficient cell line was thus completely reversed by transduction of an exogenous gene coding for a 5-FU-anabolizing enzyme.     

烟酰胺对实验性心肌损伤血浆内皮素影响及心肌保护作用

目的 :探讨烟酰胺对大鼠实验性心肌损伤血浆内皮素 ( ET)影响及心肌保护作用。方法 :用 Wistar大鼠 60只 ,随机分为心肌损伤模型组、烟酰胺治疗组和对照组 ,每组 2 0只。测定血中ET、肌酸磷酸激酶 ( CPK)、乳酸脱氢酶 ( L DH)变化并观察心肌组织学损害程度。结果 :模型组与对照组比较血中 ET、CPK、LDH明显增高 ( P <0 .0 5 ) ,心肌组织学损害程度较重。治疗组与模型组比较血中 ET、CPK、L DH显著下降 ( P<0 .0 5 ) ,组织学受损程度轻、例数少。治疗组与对照组比较血中 ET、CPK、L DH无显著性差异 ( P >0 .0 5 )。结论 :烟酰胺对大鼠实验性心肌损伤有明显的保护治疗作用。     

烟酰胺对甲基苯丙胺注射后大鼠脑组织中SOD、NO和MDA表达的影响

目的：观察甲基苯丙胺（MA）所致大鼠脑组织中一氧化氮（NO）、超氧化物歧化酶（SOD）、丙二醛（MDA）的变化及烟酰胺（Nicotinamide,Ni）的保护作用。方法：实验分为4组,分别给予MA,Ni,MA＋Ni和生理盐水,观察4组脑组织中NO、SOD、MDA的变化及相互关系。结果：MA给药模型中SOD的含量有显著性下降,NO和MDA均有显著性上升。预先应用Ni能使SOD的下降和NO与MDA的上升显著减轻,MA＋Ni组与MA组间比较,差异有显著性意义（P〈0.01）。结论：Ni可以减轻MA对神经的损伤,其机制可能与提高SOD活性,清除氧自由基抑制脂质过氧化有关。     

Promotion of β-cell differentiation by the alkaloid conophylline in porcine pancreatic endocrine cells

We previously found that conophylline, an alkaloid isolated from the leaves of Ervatamia microphylla, induced β-cell differentiation in rat pancreatic acinar carcinoma cells and in cultured fetal rat pancreatic tissue and that it also decreased the blood glucose level in streptozotocin-treated fetal rats. In the present research, we looked into the effect of conophylline on the differentiation of newborn pig pancreatic endocrine cells into insulin-secreting cells. Conophylline potentiated the differentiation of monolayer cells into insulin-producing cells in the presence of nicotinamide in 3 weeks. Next we prepared islet-like cell clusters (ICC). Cononophylline together with nicotinamide also increased the number of insulin-producing cells and the insulin content in ICC in 3–6 weeks. The ICC thus prepared were sensitive to the glucose concentration for the insulin secretion. Conophylline increased the mRNA expression of PDX-1, neurogenin3, neuroD/Beta2, and insulin in ICC. Thus, the vinca alkaloid conophylline potentiated β-cell differentiation in porcine pancreatic endocrine-rich cells in cluster cultures. Pig pancreatic cells are practical candidate for use in transplantation therapy. Conophylline may thus be useful for the large-scale preparation of porcine insulin-producing cells for the regeneration therapy of type-1 diabetes mellitus.     

脂联素和内脂素与胎儿生长发育的关系

目的 探讨脂肪因子--脂联素和内脂素与胎儿生长发育的关系.方法 收集2007年6月至12月北京军区总医院妇产科住院分娩的产妇42例,其中分娩胎儿生长受限(FGR)儿14例(FGR组),分娩巨大儿14例(巨大儿组),分娩出生体重正常新生儿14例(对照组).采用酶联免疫吸附试验(ELISA,双抗体夹心法)检测3组产妇血和新生儿脐血中的脂联素和内脂素的水平,并分析新生儿脐血中脂联素和内脂素水平与产妇血中水平的相关性.结果 (1)FGR组产妇血中内脂素水平为(41.4±5.5)μ/L,明显高于对照组的(34.7±4.9)μ/L和巨大儿组的(37.3±4.4)μ/L,分别比较,差异均有统计学意义(P<0.01,P<0.05);巨大儿组产妇血中脂联索水平为(4.1±1.3)mg/L,显著低于对照组的(6.6±1.5)mg/L和FGR组的(6.4±1.3)mg/L,分别比较,差异均有统计学意义(P均<0.01).(2)FGR组新生儿脐血中内脂素水平为(58.1±7.6)μ/L,明显高于对照组的(42.6±7.8)μ/L和巨大儿组的(48.5±9.1)μ/L,分别比较,差异均有统计学意义(P<0.01,P<0.05);巨大儿组新生儿脐血中脂联素水平为(6.5±1.3)mg/L,低于对照组的(7.7±1.5)mg/L和FGR组的(7.7±1.0)mg/L,分别比较,差异均有统计学意义(P均<0.05).(3)脐血中内脂素水平高于产妇血中的水平,两者呈显著正相关关系(r=0.720,P<0.01);脐血中脂联素水平略高于产妇血中的水平,两者无明显相关性(r=0.301,P>0.05).结论 内脂索水平的升高可能与FGR的发生有关,脂联素水平的降低可能与巨大儿的发生有关.     

烟酰胺对1型糖尿病的防治作用及其机理

目的　探讨烟酰胺 (Nicotinamide ,NAA)对 1型糖尿病 (1-DM)的防治作用 方法　NAA 1.2g/m2 .d治疗 1型糖尿病 48例 ,连续口服 4个月 .结果　 16例血基础C -肽 (CP)和胰高糖素刺激后 6分钟C -肽 (6’ -CP)显著升高 ;其中 8例出现蜜月期 ,5例胰岛细胞抗体 (ICA)和胰岛素自身抗体 (IAA)均阳性 ,3例为ICA阳性 ;蜜月期发生于治疗后第 3～ 12周 ;随访 18个月 ,其中 5例需恢复INS治疗 .其余的 32例治疗并随访 12个月以上 ,C -肽有上升趋向 .结论　烟酰胺对 1型糖尿病早期的胰岛 β细胞有一定的保护作用 .     

Bioenergetics of aging and calorie restriction

Aging is a physiological process that involves a multi-factorial set of deleterious changes. These alterations are caused by an exponential increase in damage to macromolecules. This process is likely due to the cumulative effects of oxidative stress over time. One area of ongoing research in gerontology has focused on determining why there is an age-dependent decrease in cellular bioenergetics. The aim of this review is to summarize the recent findings on the effects of aging and calorie restriction on energy metabolism. The effect of calorie restriction on age-associated changes in bioenergetic parameters will be examined.