Suppression of voltage-dependent K+ currents in retinal bipolar cells by ascorbate

Ascorbate, often used as an antioxidant in neural studies, may also serve as a neuromodulator in the vertebrate central nervous system (CNS), in that it modulates the synaptic actions of glutamate and dopamine. Retina of fish contain a high concentration of ascorbate. The release and/or uptake of neurotransmitters are related to membrane potential, which to a large extent is determined by the activity of K+ channels. As retinal bipolar cells are subject to synaptic input from glutamatergic and dopaminergic sources, the effects of ascorbate on voltage-dependent K+ currents (I(K)(v)) of the mixed rod-cone ON-center bipolar cells (Mb) in goldfish retinal slices were studied using whole-cell recording techniques. I(K)(V) was suppressed reversibly 60% by 100-200 microM ascorbate. The effect of ascorbate was not due to changes in pH, oxidative stress, lipid peroxidation, any Ca2+-dependent or Na+-dependent action. However, the suppressive effect of ascorbate was blocked by cholera toxin and Wiptide, a protein kinase A (PKA) inhibitor. It is concluded that ascorbate, at physiological concentrations, inhibits I(K)(V) of bipolar cells via a Gs-protein-PKA system. This effect of ascorbate should be taken into account when using ascorbate as an antioxidant in retinal studies involving dopamine.     

氯地滴眼液对家兔眼压及房角组织影响的研究

目的 观察氯地滴眼液对家兔眼压及房角组织影响。方法 用６０只家兔设实验和对照组,以含０．１７５％氯霉素和０．１５％地塞米松的氯地跟液滴眼,每日４次,生理盐水对照。于１／２、１、２、３月测眼压后处死家兔以电镜观察房角组织变化。结果 眼压和房角组织结构与对照组无明显差异。结论 临床应用氯地眼液３月内是安全的。     

左旋四氢巴马汀对单个豚鼠心室肌细胞钙电流的阻滞作用

AIM: To study the effect of l-tetrahydropalmatine (l-THP) on L-type calcium channel. METHODS: Patch clamp technique (whole cell recording) was used to record L-Ca2+ current in single cardiac myocyte. RESULTS: 1) l-THP 1, 10, and 100 micromol.L-1 reduced ICa-max from (999 +/- 93) pA to (700 +/- 111) pA, (582 +/- 66) pA, and (420 +/- 112) pA (n = 6, P < 0.01), respectively. 2) l-THP reduced the voltage at half-maximal inactivation (V1/2) of L-Ca2+ channel to more negative potentials by 9 mV (n = 5, P < 0.05). 3) l-THP caused both tonic and use-dependent reduction of Ca2+ current. Tonic block of l-THP on Ca2+ current was 46% +/- 8% (n = 6, P < 0.01). The degree of use dependent blocking was 13.5% +/- 2.4% (n = 6, P < 0.05) at 1 Hz, the degree increased to 44% +/- 5% (n = 6, P < 0.01) at 3 Hz. 4) l-THP delayed half-recovery time of Ca2+ channel recovery from inactivity from (94 +/- 39) ms to (170 +/- 42) ms(n = 6, P < 0.01). CONCLUSION: l-THP has a moderate inhibitory effect on L-Ca2+ current.     

Interleukln-8 stimulates angiogenesis in rats

To test the hypothesis that the cytokines interleukin-6 (IL-6) and IL-8 may play regulatory roles in the aberrant neovascularization in chronic inflammatory diseases, we examined their effects in a rat sponge model and compared their actions with those of IL-1 and lumor necrosis factor- (TNF-). Daily doses of 3 pmol IL-8, IL-1, TNF-, but nol IL-6, significantly accelerated the sponge-induced angio-genesis. Although lower doses (0.3 pmol) of these cytokines were inactive, IL-1 acted synergistically with subthreshold daily doses (10 pmol) of substance P (SP) and bradykinin (BK) to produce an intense angiogenic response. In contrast, IL-8 only interacted positively with IL-1, but not TNF-, SP, or BK. There was no synergism or antagonism between IL-6 and SP. These results demonstrate the discrete interactions between angiogenic factors and cytokines in chronic inflammation and suggest that the sponge model is a good means for the study of such interactions.     

A study on the expression of TGF-beta 1/T beta R II in laryngeal carcinoma]

OBJECTIVE: To explore the expression of TGF-beta 1/T beta R II in laryngeal carcinoma. METHOD: Immunohistochemical study using SP kit in 53 cases. RESULT: The expression of TGF-beta 1 was decreased in carcinoma tissues when compared with peri-cancer controls (P < 0.05). There wasn't difference in T beta R II expression when compared with peri cancer controls (P > 0.05). But it was correlated with the stage, differentiation and lymph node metastasis of laryngeal carcinoma. CONCLUSION: TGF-beta 1/T beta R II may involve in the histogenesis and development of laryngeal carcinoma. The decreased expression of TGF-beta 1/T beta R II may serve as an important molecular marker of laryngeal carcinoma.     

微细药物表面包覆技术在制剂中的应用

新型药物开发制备过程中，需要对药物颗粒进行粒子设计，通过多层微胶囊化而得到复合包覆药物颗粒。药物包覆、微胶囊制备方法很多，可分为化学法、物理化学法、物理法。本文着重介绍了制备复合多层包覆药物颗粒的几种物理机械方法：复合杂化系统，高速椭圆转子混合法、喷流床包覆法。简要分析了该技术用于中药现代化加工的可能性。     

Synthesis and physico‐chemical properties of peptides in soil humic substances

Abstract: Soil humic substances (HS) are heterologous, polydispersive, and multi‐functional organometallic macromolecules ubiquitous in soils and sediments. They are key players in the maintenance of the belowground ecosystems and in the bioavailability of both organic and inorganic contaminants. It is widely assumed that the peptidic substructures of HS are readily degraded and therefore do not contribute significantly to interactions with contaminants such as toxic metals. To investigate the turnover of humified peptides, laboratory soil aging experiments were conducted with ¹³C‐glucose or ¹⁵N‐nitrate for 8.5 months. Evidence for random‐coil peptidic structures in the labeled HS was obtained from 2‐D nuclear magnetic resonance (NMR), pyrolysis gas chromatography‐mass spectrometry (pyro‐GC‐MS), and circular dichroism data. Interaction of metals with the peptidic carbonyls of labeled HS was rationalized from the solid‐state NMR data. Detailed ¹³C and ¹⁵N labeling patterns of amino acid residues in the acid hydrolysates of HS acquired from NMR and GC‐MS revealed two pools of peptides, i.e. one extant (unlabeled) and the other, newly humified with little isotopic scrambling (fully labeled). The persistence of pre‐existing peptidic structures indicates their resistance to degradation while the presence of fully labeled peptidic amino acids suggests wholesale incorporation of newly synthesized peptides into HS. These findings are contrary to the general notion that humified peptides are readily degraded.     

人单核巨噬细胞泡沫化抑制剂筛选模型的建立及应用

目的: 建立人单核巨噬细胞泡沫化抑制剂筛选模型,筛选得到可抑制细胞泡沫化的抑制剂.方法: U937单核细胞经100 nmol·L-1佛波酯(PMA)诱导72 h分化为巨噬细胞后,换无血清培养液于96孔板中,每毫升含巨噬细胞1×106个,每孔再加入80 mg·L-1氧化的低密度脂蛋白(ox-LDL),37 ℃培养48 h,建立单核巨噬细胞泡沫化模型.利用微生物发酵液,或单一的化合物样品与其共孵育,油红.染色后观察细胞胞内变化,寻找对泡沫细胞形成有抑制作用的样品.利用基因工程技术表达的人清道夫受体A类II型的胞外部分,在本模型中可抑制巨噬细胞泡沫化的形成,进一步验证了模型的可行性.结果: 从2000 个微生物发酵液中筛选到6株微生物发酵液为阳性,从10个化合物中发现一个有抑制巨噬细胞泡沫化活性的新化合物.结论: 本模型可用于细胞泡沫化抑制剂的高通量筛选.     

妊娠晚期人类小DNA病毒B19感染情况,母婴传播及与早产或小于胎龄儿关系的研究

为了解妊娠晚期人类小ＤＮＡ病毒Ｂ１９（ＨＰＶＢ１９）感染情况、母婴传播及与早产或小于胎龄儿的关系，将１０４例母亲及其新生儿分成两组，试验组包括１９例早产儿、３２例小于胎龄儿及其母亲；对照组包括５３例正常新生儿及其母亲。采用聚合酶链反应技术（ＰＣＲ）检测母血、脐血和胎盘组织ＨＰＶＢ１９ＤＮＡ；用鼠抗Ｂ１９单克隆抗体和Ｂ１９联合抗原（ＶＰ１＋ＶＰ２）建立了捕获式ＥＬＩＳＡ法检测母血和脐血ＨＰＶＢ１９特异性ＩｇＭ抗体。结果：１０４例母血中，ＨＰＶＢ１９ＩｇＭ阳性２例（１．９％），１０４例脐血中阳性３例（２．９％）。在母血、脐血及胎盘组织各１０４例中检出ＨＰＶＢ１９ＤＮＡ阳性分别为６例、４例、６例。因此试验组５１对母婴共１０２例中６例有ＨＰＶＢ１９感染（５．９％）；对照组５３对母婴共１０６例中２例有ＨＰＶＢ１９感染（１．９％）。两组Ｂ１９感染率差异无显著意义。提示：在北京地区，妊娠晚期存在Ｂ１９急性感染，应引起重视；Ｂ１９感染与早产或小于胎龄儿的发生可能不相关；新生儿Ｂ１９感染是通过胎盘传播的。对有Ｂ１９感染证据的新生儿进行随访及研究如何阻止胎盘传播很重要。