γ射线诱发人正常肝细胞基因组不稳定性研究

目的探讨电离辐射诱发的基因组不稳定性效应。方法采用^60Co γ射线照射人正常肝细胞，检测克隆形成率和微核发生率，利用单细胞凝胶电泳（SCGE）技术检测DNA损伤情况。照射2、4、6、8和10Gy后传代培养，在40代后各剂量组再次统一照射2Gy，进行辐射损伤的检测。结果首次照射后，克隆形成率随受照剂量的增大而降低。存活细胞经二次照射后，SCGE结果和微核发生率结果表明，首次照射剂量与子代二次照射后的损伤程度存在剂量效应关系。结论γ射线不仅在肝细胞中产生直接的生物效应，而且还可以诱发产生可遗传的基因组不稳定性，使子代细胞中的突变频率增加，表现出滞后的遗传改变。二次事件的放大作用是研究基因组不稳定性的一种较好方法。     

单纯或联合药物治疗复发性外阴阴道念珠菌病48例疗效分析

目的 :探讨两种方法治疗复发性外阴阴道念珠菌病的效果。方法 :将 4 8例复发性外阴念珠菌阴道炎的患者随机分为两组 ,分别给予两种治疗方法。Ⅰ组 (2 5例 ) :每晚米可定泡腾片 1片塞入阴道 ,连续用药 7～ 10d。首次用药后 1周复查 ,临床及白带真菌学培养阴性进入维持期治疗 ,即每周 1次米可定泡腾片 1片阴道塞 ,连续 5个月。Ⅱ组 (2 3例 ) :单次口服氟康唑15 0mg外加每晚米可定泡腾片 1片阴道塞 ,连续用药 7～ 10d。首次用药后 1周复查 ,临床及白带真菌学培养阴性进入维持期治疗 ,即每月月经第 1天口服氟康唑 15 0mg外加每周 1次米可定泡腾片 1片阴道塞、连续 5个月。结果 :首次治疗后 1周及第1个月、12个月两组的治愈率、无效率及假阳性率统计学结果无差异 (P >0 .0 5 ) ,而维持治疗第 1、3和 6个月Ⅱ组的治愈率显著高于Ⅰ组、无效率显著低于Ⅰ组 (P <0 .0 5 )。结论 :氟康唑口服与米可定泡腾片阴道联合用药半年能有效减少治疗期间复发率 ,但停药后并不能降低复发率。     

Single unit activity in the auditory cortex of a monkey performing a short term memory task

Summary Short term memory to tones (STMT) was investigated by recording single unit activity in the auditory cortex of a behaving monkey. The activity of each unit was studied in two behavioral conditions: a) During task performance, the monkey had to compare two tones separated by one second of silence (inter-stimulus interval), b) During a nonperforming period; the monkey heard the two tones but did not respond behaviorally. It was noted that the firing rate of many units during the inter-stimulus interval (ISI) was dependent on the frequency of the first tone. Such dependency was observed even towards the end of the ISI, both during task performance trials (50% of the units) and during the nonperforming period (32% of the units). The activity of these units could be the basis of STMT in both of these behavioral states. In 65% of all the units tested, the responses during the ISI were of a higher magnitude in the performance period than were the responses in the non-performance period. The activity of these units may be related either to general processes such as attention and expectation or to short-term memory processes. During task performance, the responses of 23% of the units to the second tone were dependent on whether its frequency was identical to that of the first tone. Such dependency was never observed during the non-performing period. These units may detect similarity or non similarity between two tones presented one second apart. Periodic patterns of firing were not found in the study, thus suggesting that the ISI responses were not generated by reverberatory activity in simple closed loops. On the basis of these results, several alternative mechanisms of STMT are suggested.     

Acetylcholine produces stimulus-specific receptive field alterations in cat auditory cortex

Frequency receptive fields (RFs) were determined before and after pairing iontophorectic administration of acetylcholine (ACh) with a repeated single-frequency stimulus in the auditory cortex of barbiturate-anesthesized cats. In 58% of the cells, the paired ACh + tone treatment produced subsequent alterations of frequency RFs. In half of these cases, the RF modifications were highly specific to the frequency that had been paired with ACh. Atropine antagoized the frequency-effects of ACh, suggesting that they were mediated via muscarinic cholinergic receptors.     

SLE小鼠高IgG血症Fcgr2b基因序列分析

目的: 测定系统性红斑狼疮(SLE)小鼠模型-NZB/WF1双亲NZB,NZW小鼠 Fcgr2b基因启动子区核酸序列,明确Fcgr2b基因启动子区的突变性质.方法:扩增NZB,NZW小鼠Fcgr2b基因启动子DNA进行核酸序列分析.采用ELISA法测定、比较(NZB×NZW )F1×NZW回交小鼠Fcgr2b基因B/W型与W/W型组间血清总IgG 水平.结果:NZB小鼠Fcgr2b基因启动子区与正常鼠Balb/C相比存在2个部位碱基缺失,分别为13 bp及3 bp.NZW小鼠除有3个碱基置换外,与Balb/C鼠该基因启动子区序列相同.回交小鼠Fcgr2b基因B/W型组血清总 IgG水平明显高于W/W型组(P<0.0001).结论:NZB小鼠Fcgr2b基因启动子区存在碱基缺失,且该缺失突变可能与血清总IgG水平升高有关.     

Assessment of changes in regional cerebral blood flow in patients with major depression using the 99mTc-HMPAO single photon emission tomography method

Regional cerebral blood flow was investigated in 14 patients with major depression diagnosed according to the DSM-III-R criteria (six patients with single and eight patients with recurrent episodes) and in ten healthy volunteers. The mean ages of the patients and the controls were 33.5 ± 2.7 and 31.6 ± 2.6 years, respectively. The severity of the depression was assessed using the 17-item Hamilton Depression Scale (mean: 23.2 ± 1.5). None of the patients was under medication. After administration of 500 MBq technetium-99m hexamethylpropylene amine oxime, a single photon emission tomography study was performed and then transaxial, sagittal and coronal slices were obtained. For the semiquantitative analysis of the data, the ratios of the mean counts/pixel to the whole slice were calculated for 24 regions on three consecutive transaxial slices in the orbitomeatal plane. Additionally, left/right and frontal/occipital ratios were calculated. Both sides of the temporal region had a significantly decreased cerebral blood flow (CBF) when compared to the controls. The left/right ratio of the prefrontal region was also significantly lower in the patients than in the controls. The Hamilton score had a negative correlation with blood flow in the anterofrontal and left prefrontal regions. According to our results, regional CBF seems to be decreased in the left prefrontal and in both temporal regions in major depression. The severity of depression is correlated with the reduction in CBF in the regions of the anterofrontal and left prefrontal cortex.     

Activities of creatine kinase isoenzymes in single skeletal muscle fibres of trained and untrained rats

Biochemical changes in the creatine kinase isoenzyme compositions in single muscle fibres of different types in rats were induced by endurance running training. Single muscle fibres were dissected from the soleus and extensor digitorum longus muscles of Wistarstrain male rats trained on a motor-driven treadmill for 16 weeks. Each fibre was typed histochemically (SO, slow-twitch oxidative; FOG, fast-twitch oxidative glycolytic; FG, fast-twitch glycolytic), and the activities of total creatine kinase and its four isoenzymes (CK-MM, -MB,-BB, and mitochondrial creatine kinase) were measured. The endurance training did not affect the total creatine kinase activity, but resulted in significantly increased activities of CK-MB and CK-BB in SO and FOG fibres, and the mitochondrial enzyme activity in FOG and FG fibres. Endurance training induced biochemical changes in the isoenzyme compositions, specifically in FOG fibres. These results suggest that changes in creatine kinase isoenzymes with endurance training reflect changes in the energy metabolism in the different muscle fibres, supporting the hypothesis that the different isoenzymes play different roles in energy transduction.     

Unilateral lesion of the nigrostriatal pathway decreases the firing rate and alters the firing pattern of globus pallidus neurons in the rat

Activities of spontaneously firing neurons in the globus pallidus of intact rats and rats that survived unilateral lesions of the nigrostriatal pathway for 3 days, 1 week, or 6-11 weeks were compared. No significant differences in neuronal firing rate, firing pattern, and number of cells per pass were observed between chloral hydrate-anesthetized control and lesioned animals. However, in locally anesthetized animals, pallidal cells fired significantly faster than in chloral hydrate-anesthetized animals, and the lesion caused a decrease in the firing rates of pallidal cells 1 week and 6-9 weeks postlesion. In addition, significant differences in the firing pattern of pallidal cells, as determined by the ratio of the mean to median interspike intervals, were seen between locally anesthetized controls and animals surviving 3 days, 1 week, and 6-9 weeks postlesion. This altered firing pattern tended to return to normal with time. The number of cells per pass was not significantly altered by the lesion. Data from this study suggest that, in locally anesthetized animals, the removal of the tonic dopaminergic input to the basal ganglia causes pallidal cells to decrease their firing rates in a time-dependent fashion and causes reversable firing pattern changes. This suggests that tonically active dopamine neurons, probably acting through the striatopallidal pathway, regulate the firing rate and mechanisms controlling the temporal ordering of spontaneous discharges of globus pallidus neurons.     

Single photon emission computerized tomography in childhood hydrocephalus

Single photon emission computerized tomography (SPECT) is now widely used as one of the tools in evaluating cerebral blood flow (CBF). The authors report the CBF changes in childhood hydrocephalus. Five pediatric cases studied by ¹²³I-IM SPECT in children are presented. The authors counted radioactivities both in early and delayed images in each patient, and calculated the reabsorption ratio (RR). Two negative-RR cases and three positive-RR cases were found. All of the negative-RR patients had a poor prognosis, while all of the positive-RR patients had a favorable outcome.