GM6001的玻璃体代谢及视网膜毒性作用的研究

目的：评价人工合成的金属蛋白酶抑制剂GM6001在玻璃体中的代谢及其眼内安全性。方法：选择健康成年的青紫蓝兔16只，随机分成4组，右眼分别玻璃体房注射GM6001各0．05mL（A组100μmol、B组75μmol、C组50μmol和D组25μmol）。左眼分别注射PBS0．05mL作为对照。各组术后不同时间取玻璃体样本，应用高效液相色谱分析仪检测其中GM6001的浓度。术前术后进行裂隙灯、间接检眼镜和视网膜电图（ERG）检查，最后处死动物对视网膜进行光镜及透射电镜的检查。结果：术后前3d，玻璃体房GM6001浓度下降迅速，而后保持缓慢降低至术后28d完全清除。术后裂隙灯、间接检眼镜、ERG检查、视网膜光镜及透射电镜观察，各组均未发现异常改变。结论：GM6001在玻璃体房注射对视网膜是安全的。GM6001在单次玻璃体房注射后2wk可维持有效浓度。     

顺铂聚乳酸微球的药物释放特性及肝动脉栓塞研究

对顺铂聚乳酸微球进行了体外药物释放和家犬肝动脉栓塞研究。该微球粒径范围为50～200μm,平均粒径为115.76±35.94μm,顺铂含量为37.16%(W/W);体外药物释放机制符合Higuchi方程;肝动脉栓塞后8h,肝组织顺铂浓度高达21.55±12.18μg/g,明显高于肝动脉灌注顺铂组:3.16±0.09μg/g(P<0.05);肝动脉栓塞组的顺铂血浓峰值、各取血点浓度及曲线下面积AUC皆低于肝动脉灌注顺铂组。可望达到提高栓塞部位的药物疗效,降低全身毒副反应的作用。     

Chronic opioid treatment of neuroblastoma X dorsal root ganglion neuron hybrid F11 cells results in elevated GM1 ganglioside and cyclic adenosine monophosphate levels and onset of naloxone-evoked decreases in membrane K+ currents

Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via G_s regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K⁺ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the G_s/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc.     

Cholera Toxin B-Mediated Targeting of Lipid Vesicles Containing Ganglioside GM1 to Mucosal Epithelial Cells

Purpose. To determine whether the non-toxic pentameric B subunit of Cholera toxin (CTB) binding to ganglioside GM1 on both the lipid vesicles and epithelial cells may provide a means to target lipid vesicles to mucosal cells expressing surface GM1. Methods. Sonicated lipid vesicles containing ganglioside GM1 were prepared. Inter-vesicle cross-linking due to pentameric CTB binding to these GM1 vesicles was determined with a sub-micron particle analyzer. Association of CTB to GM1 vesicles was analyzed with continuous sucrose gradient centrifugation. CTB-mediated binding of GM1 vesicles to human mucosal epithelial cells (Caco-2 and HT-29), mucous membranes of mouse trachea, and nasal tissues were detected with fluorescent labeled vesicles. Results. An increase in lipid particle size due to binding of CTB to lipid vesicles and inter-vesicles cross-linking was detected. At a 30-to-1 mole ratio of membrane-bound GMl-to-CTB, optimum increase in GM1 vesicle aggregation, was detected. Under such conditions, all the added CTB molecules were associated with GM1 vesicles. Time course analysis showed that inter-vesicles cross linking by CTB was detectable within 10 min. and reached a maximum value at 60 min. CTB associated GM1-vesicles bind to mucosal epithelial cells HT-29 and Caco-2 with similar affinity [K_d = 7.8 × 10^–4 M lipid (Caco-2) and 7.6 × 10^–4 M lipid (HT-29)]. GM1 mediated binding specificity was demonstrated by blocking with anti-GMl antibody and the insignificant degree of CTB-associated GM1 vesicle binding to GM1 deficient C6 cells. Conclusions. The CTB-mediated GM1 binding to multiple membrane surfaces provides selective localization of GM1 vesicles to GM1 expressing mucosal cells and tissues. The strategy may be useful in localizing drugs and proteins to gut and respiratory tract mucosa.     

干细胞动员对骨创伤大鼠免疫功能的保护作用

目的：观察自体干细胞动员对骨创伤大鼠的免疫功能的保护作用，为战创伤后的免疫抑制及继发性感染、系统性炎症反应等治疗提供依据。方法：挤压折断法复制大鼠双后肢股骨骨折模型，于致伤后0、24、48h连续给模型动物肌肉注射GM—CSF20μg／kg，致伤后72h细胞增殖法检测T、B淋巴细胞活性，ELISA法检测血清IL-1、IL-2、IFN-7、TNF—α浓度，自动系列化分析法检测C3、CA、IgM、IgG浓度，称重法观察脾重与体重的比例变化。结果：股骨骨折模型大鼠致伤后72h，GM—CSF动员骨髓干细胞组大鼠的T、B淋巴细胞活性和血清IFN-γ、IL-2浓度高于对照组（P〈0．01），IL-1、TNF—α浓度低于对照组（P〈0．01），血清C3、CA、IgM、IgG浓度及脾／体重比值高于对照组（P〈0．01）。结论：GM—CSF动员自体干细胞动员对大鼠骨创伤诱导的免疫功能抑制具有保护作用。     

GM1 ganglioside partially rescues cultured dopaminergic neurons from MPP-induced damage: dependence on initial damage and time of treatment

GM1 ganglioside is believed to be important in promoting the recovery of neurons from injury. The present study assesses the ability of GM1 to repair or prevent the damage of dopamine neurons caused by the neurotoxin 1-methyl-4-phenylpyridinium (MPP⁺). Treatment of mesencephalic cell cultures with 2.5 μM MPP⁺ resulted in the loss of 30% of tyrosine hydoxylase (TH) immunoreactive neurons. In contrast, cultures administered 100 μM GM1 ganglioside for 3 days after toxin treatment contained nearly control numbers of TH⁺ neurons (97%). This reparative effect of GM1 was reflected in parallel increases in TH enzyme activity, dopamine and dopac levels. Cultures sustaining greater insult from higher doses of MPP⁺ (5.0–10.0 μM) did not benefit from ganglioside treatment, suggesting that rescue by GM1 depended on the degree of initial damage to cells. Moreover, the timing of ganglioside treatment was critical; pretreatment with GM1 alone did not prevent or attenuate the damage caused by subsequent incubation in 2.5 μM MPP⁺.     

Characterization of an anti-idiotypic MoAb bearing an internal image of the receptor-binding epitope of cholera toxin.

A mouse anti-cholera toxin (CT) MoAb, mAb1, specific for the GM1-binding epitope of CT, was used to raise a syngenic anti-idiotypic MoAb, mAb2. Purified mAb2 was specific for mAb1 as shown by latex particle counting immunoassay and ELISA. Several experiments of competition between mAb2 and CT for binding to mAb1 demonstrated that mAb2 bore an internal image of the GM1-binding epitope of CT. Binding of mAb2 to GM1 unambiguously corroborated the mAb1-paratopic specificity of mAb2. Furthermore, mAb2 acted as a CT-surrogate antigen: rabbits injected with mAb2 produced some anti-CT antibodies, Ab3, which resembled mAb1 in specificity as expected. The potential use of this mAb2 as vaccine or as prophylactic agent to prevent CT from binding to its cellular receptor is discussed.     

空管药物疗法治疗牙髓病和根尖周病疗效观察

用ＳＭＴＤ复合药物对牙髓病和根尖周病实施空管药物疗法。７８例１０３颗获得完整随访资料患牙经两年观察，９２．２％治愈率。文章介绍了治疗方法，讨论了空管药物疗法的愈合机理、优点、失败原因及其预防措施。     

GM and KM allotypes in eight tribal populations of madyha Pradesh and Orissa, India

Summary Serum samples from eight endogamous Indian tribal populations of Madhya Pradesh (Dhurwa, Halba, Bhatra, Muria, Maria) and Orissa (Deshia Khond, Binjhal, Kisan) with a total of n=731 unrelated individuals were typed for G1M (1,2,3,17), G3M (5,10,11,13,14,15,16,21,26), and KM (1). In seven of these populations five different GM haplotypes were found:GM*1,17;21,26; GM*1,17;10,11,13,15,16; GM*1,2,17;21,26; GM*1,3;5,10,11,13,14,26; andGM*3;5,10,11,13,14,26. In the Kisan sample the haplotypeGM*1,2,17; 21,26 is absent. The intergroup variability in the distribution of these haplotypes is considerable and statistically highly significant. The reasons for that can be attributed to the ethnohistory and to the genetic isolation of these eight endogamous tribal populations. The GM haplotype distribution pattern of all these groups is quite different from that of the non-tribal populations of India, whereas it is in good agreement with that of the so far tested other tribal populations from India. This can be explained by different origin and history of the Indian tribal and non-tribal populations. In the KM system, too, remarkable variability is seen in the distribution of phenotype and allele frequencies among the eight tribal populations under study.     

An enzyme-linked immunosorbent assay (ELISA) for the measurement of antibodies to different parts of the gram-negative lipopolysaccharide core region

Bovine serum albumin was complexed with the core antigens of either Escherichia coli J5 LPS, Salmonella minnesota R595 LPS or E. coli lipid A. These core-BSA complexes were used for solid-phase coating in ELISAs for anti-core antibodies. Antibodies, binding to various parts of the core region were easily quantified in a single experimental set-up, which was hitherto not possible. The ELISA has only 3 incubation steps and is not costly as only moderate amounts of the core antigens (i.e., 1 microgram per test) were needed for coating. The sensitivity proved to be excellent and the complexes were biologically fully active (compared to native, smooth LPS), which make them suitable for the screening (after fusion) of monoclonal anti-core antibodies. Another possible application is the large-scale screening of blood-bank sera in order to find samples with a high anti-core antibody content.