Pathological Effects of Matebrnal Hypoglycemia on Fetal Development in Cats

The pathogenesis of fetal brain damage caused by acute maternal hypoglycemia was investigated experimentally in cats: profound hypoglycemia (blood glucose concentration:less than 30 mg/dl) was induced in 12 pregnant cats at various stages of gestation by intravenous bolus injections of insulin. Maximal hypoglycemia was attained within 2 3 h, although the grade and duration in individual cats varied. The EEGs of all of seven maternal cats examined showed an increased frequency of slow high-voltage waves as hypoglycemia progressed, eventually becoming flat in 3 for a maximum period of 20 min. Some fetuses showed severe neuropathological changes, such as infarction or intrauterine death. Subventricular soften ing, cortical hemorrhage and ischemic neuronal changes also occurred, being distributed symmetrically in the para-sagittal areas of the cerebrum, basal ganglia, thalamus and tegrnentum of the brainstem. In general, these patho logical changes were more marked in fetuses and neonates than in the maternal cats, in which only ischemic neuronal changes were present, and may have been due to fetal systemic hypotension and cerebral ischemia induced by hypoglycemia. In maternal cats, the distribution of neu rons showing ischemic changes was widest in the cerebral cortex, and some were also present in the dentate gyri of the hippocampus. Moreover, ultrastructural examination of the ischemic neurons in maternal cats, unlike those of the fetuses, showed no mitochondrial swelling. Therefore, the distribution and ultrastructural nature of the ischemic neurons found in the maternal cats were considered to be characteristic of hypoglycemia, as proposed by Agardh et al . (1980). Acta Pathol Jpn 42 : 316–324, 1992.     

Effects of "Below-Zero" Habituation on the Electrodermal Orienting Response to a Test Stimulus

Two experiments were designed to investigate the effect of below-zero habituation training on skin conductance response (SCR) amplitude to a change in auditory stimulus frequency. In both experiments, subjects were trained with a 1000 Hz tone until zero responding and then received 5, 10, or IS further training trials. In Experiment 1 (N=45), subjects then received 1 presentation of a test stimulus of 1400 Hz, while in Experiment 2 (N=45), the test stimulus was a tone of 670 Hz. On the basis of dual-process theory, it was hypothesized that response amplitude to the test stimulus would be inversely related to amount of below-zero training. However, the results of both experiments indicate that SCR amplitude was positively related to amount of below-zero training. These results suggest that in situations of extended habituation training, an expectancy or subjective probability of stimulus occurrence gradient is important in determining response amplitude to a test stimulus.     

Family History of Hypertension and Cardiovascular Responses to Orthostatic Stress

Cardiovascular effects of orthostatic stress (sitting to standing) were assessed in 60 healthy young male subjects according lo family history of hypertension (half with a positive and half with a negative family history' of hypertension). Systolic (SBP) and diastolic blood pressure (DBF) were recorded on each successive heart heal using a non-invasive blood pressure tracking system. Heart rate (HR) and respiration rate (RR) were also recorded. During the postural change, characteristic phasic changes were shown with an initial fall and subsequent recover of SBP and DBF and a mirror image response in MR and RR. Phasic analysis of the pre-standing sit, peak/trough, and recovery stand values indicated group differences in the initial as well as the later phases of orthostatic response. In the initial phase, subjects with a positive family history of hypertension showed an earlier trough in systolic and pulse pressure and an earlier peak in heart rate response immediately on standing up. The level of the pulse pressure trough was also higher in these subjects. In the later standing phase, these subjects showed higher levels of pulse pressure. The results were interpreted in terms of increased sympathetic nervous system activity during the initial phase and structural and neurocirculatory abnormalities in the later phase of orthostatic regulation in individuals with a positive family history of hypertension.     

Dynamic changes in corticospinal excitability during motor imagery

 We investigated temporal changes in the amplitudes of motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation over the left motor cortex during motor imagery. Nine subjects were instructed to imagine repetitive wrist flexion and extension movements at 1 Hz, in which the flexion timing was cued by a tone signal. Electromyographs (EMGs) were recorded from the first dorsal interosseous, flexor carpi radialis and extensor carpi radialis muscles of the right hand, and magnetic stimulation was delivered at 0, 250, 500 and 750 ms after the auditory cue. On average, the evoked EMG responses were larger in the flexor muscle during the phase of imagined flexion than during extension, whilst the opposite was true for the extensor muscle. There were no consistent changes in the amplitudes of MEPs in the intrinsic hand muscle (first dorsal interosseous). The EMG remained relaxed in all muscles and did not show any significant temporal changes during the test. The H-reflex in the flexor muscle was obtained in four subjects. There was no change in its amplitude during motor imagery. These observations lead us to suggest that motor imagery can have dynamic effects on the excitability of motor cortex similar to those seen during actual motor performance. Received: 23 July 1998 / Accepted: 26 October 1998     

Evolution of semen quality in North-eastern Spain: a study in 22,759 infertile men over a 36 year period

A retrospective study was conducted in a large population to determine whether sperm quality has changed in Northeastern Spain between 1960 and 1996. From a total initial population of 22,759 men, two separate groups were studied: men with spermatozoa (n = 20,411) and those with azoospermia (n = 1364). After adjustment for age and sexual abstinence, multiple linear regression analyses were used to assess changes in semen parameters over time. A 0.2% decline was observed in semen volume in the spermatozoa group (P < 0.001). No significant increase (0.04%) in sperm count (x 10(6)/ml) was observed in the spermatozoa group. There was a 0.4% increase in motile spermatozoa in the spermatozoa group (P < 0.001). There was a statistically significant decline in normal spermatozoa (3.6%) in the spermatozoa group (P < 0.001). Of the total population, 1364 men had azoospermia (6.0%). The changes observed in the semen parameters analysed in this large population showed no evidence of a deteriorating sperm quality, although a statistically significant decline was observed in the percentage of normal spermatozoa.     

CD34+ stromal cells and hyalinized vascular changes in the anal fibroepithelial polyps

AIMS: To elucidate the pathogenesis of the anal fibroepithelial polyp, we examined surgically resected lesions histopathologically. METHODS AND RESULTS: Twenty-seven surgically resected anal fibroepithelial polyps were investigated histologically with an additional immunohistochemical examination using anti-CD34. For a control study, the surgical specimens of the anal canal showing non-polypoid lesions, obtained from haemorrhoidectomy (18 specimens) and rectectomy (five specimens) due to rectal cancer without anal canal involvement, were also analysed. We demonstrated characteristic spindle or stellate cells immunohistochemically positive for CD34 in the anal fibroepithelial polyps (24/27, 89%). The number of CD34+ cells was statistically related to the size of anal fibroepithelial polyps, although CD34+ stromal cells were recognized in the non-polypoid anal submucosa and haemorrhoids. We also found hyalinized vascular changes in the base of six anal fibroepithelial polyps examined. These features were not detected in the non-polypoid anal canal. CONCLUSIONS: An increase in CD34+ stromal cells may play a role in the enlargement of anal fibroepithelial polyps. CD34+ stromal cells are suggested to be distinctive mesenchymal cells with a capability for tissue repair and overgrowth. The vascular impairment could be secondary change associated with localized tissue damage by abnormal traction.     

The Psychological Significance of Task-Induced Tonic Changes in Somatic and Autonomic Activity

Two experiments tested the view that task-induced autonomic-somatic gradient parallelism does exist and that the steeper the physiological gradients, over the course of a task, the more involved the subject and the greater the effort. Thirty-three male subjects performed easy and difficult versions of a continuous reaction time task. In both experiments the difficult task prompted steeper electromyographic (EMG) activity gradients than did the easy version. Scores on heart rate (HR) and skin conductance did not show clear gradients. However, task-dependent effort was positively related to the magnitude of the initial HR acceleration and to the steepness of the EMG gradient. The autonomic-somatic coupling hypothesis of Obrist did not explain the results. Instead, evidence for ventilatory-somatic parallelism was found.     

溴氰菊酯对白纹伊蚊C6／36细胞株的杀伤作用及对其形态影响的研究

本文采用ＭＴＴ微量酶反应比色法，研究了溴氰菊酯对白纹伊蚊Ｃ６／３６细胞的杀伤作用、形态影响以及受损细胞的恢复。结果发现用溴氰菊酯处理２４ｈ后，对Ｃ６／３６细胞的半数毒性浓度（ＩＣ５０）为７４８８μｇ／ｍｌ，且毒性作用强度随着药物浓度增加而增强。溴氰菊酯浓度在２０μｇ／ｍｌ以上时可以诱发Ｃ６／３６细胞形态学改变，表现为细胞呈多形性、细胞间有间隙、胞质内充满颗粒，以后随药物浓度的升高，胞质出现空泡、染色质凝成粗大颗粒或无结构大块、大片细胞脱落、崩解、死亡。高浓度溴氰菊酯（１６０μｇ／ｍｌ）作用于Ｃ６／３６细胞，其受损细胞的恢复与作用时间有关，作用２４ｈ的细胞，在经历一段生长停滞后，可缓慢恢复，而作用４８ｈ的细胞，则不可逆转的死亡