Histological, histochemical and electron microscopic changes of the placenta induced by maternal exposure to hyperthermia in the rat.

Both clinical and experimental investigations have shown that maternal hyperthermia during critical stages of embryo development can induce malformations in the offspring. Studies of the effect of heat stress on the placental functions are limited to the ewes, but that on microscopic structure is unknown. In the present study, rats were exposed to 41 or 42 degrees C for 1 h on gestation day (GD) 9. The controls were sham treated. Fetuses and placentas were collected on GD 20. Intrauterine growth retardation (IUGR) and several craniofacial malformations were observed in the fetuses of the heat-treated group. The placentas of the 42 degrees C group were significantly lighter in weight than those of the control. Light microscopy (LM) revealed thickening, hyalinization and occasional lymphocytic infiltration of the decidua basalis. Giant cells were prominent and glycogen cells had degenerated, leaving behind large cysts in the basal (spongy) zone. Best's carmine stain with or without diastase indicated the reduction in number and degeneration of glycogen cells and cyst formation. The labyrinthine zone was relatively thin in comparison to that of the controls. Perivascular fibrosis and paucity of vascularization were other features of the placentas of the hyperthermia group. Electron microscopy (EM) revealed lipid droplet accumulation in the trophoblast, the presence of myelin bodies and an increased production of collagen in the basal zone. Perivascular fibrosis appeared to have contributed to placental barrier thickening. EM also revealed accumulation of glycogen and lipid droplets in the trophoblasts and fibrin secretion into the extracellular space of the labyrinthine zone. These data suggest that placental pathology possibly contributes to fetal growth retardation in maternally heat-stressed rat fetuses.     

The use of lyophilized plasma as a reference sample for determining factor VIII]

The activity of lyophilized Soviet reference plasma Factor VIII was measured by a single-stage Papayan and Khrolova's method. This factor is referent in respect of the prothrombin complex factors, stored for 18-43.5 months. Factor VIII activity was found to be within 55-135 percent. Differences in the values of antihemophilic globulin activities obtained in parallel studies in different days may be explained by the fact that the native control was not standard. The results are promising as regards the possibility of using lyophilized donor reference plasma as a reference reagent for estimation of Factor VIII activity.     

Febrile seizures

A door-to-door survey was carried out to screen a community of 14,010 people (Parsis living in colonies in Bombay, India) for possible neurological diseases. High school graduates, social workers, and a medical student administered a screening questionnaire that, in a pilot study, had a high sensitivity for identifying febrile seizures in children under the age of 14 years. Neurologists used defined diagnostic criteria to evaluate individuals positive on the screening survey. There were 1,581 children under the age of 14 years. Twenty-eight children (19 boys, 9 girls) suffered from febrile seizures (17.7/1,000 population). The present prevalence study is the first from India and suggests that, contrary to expectation, the frequency of febrile seizures may be no different in developing and developed countries.     

The electrophysiological properties of substantia nigra pars compacta neurones recorded from 6-hydroxydopamine lesioned guinea-pigs in vitro

Summary Intracellular recordings were made from substantia nigra pars compacta neurones in vitro from animals with partial unilateral 6-hydroxydopamine lesions of the nigrostriatal tract. Lesions were assessed and grouped according to the severity of the strital dopamine depletion. No differences were seen between neurones from control and lesioned side nigrae as regards their membrane properties, firing rates, burst activity or percentage of quiescent neurones in any of the lesioned categories. It is concluded that following partial lesioning, the remaining substantia nigra zona compacta neurones in vitro, are functioning normally.     

Experience with using balloon dilatation of the coronary arteries

The paper presents the analysis of balloon dilations of the coronary arteries in 18 patients with ischemic heart disease. A multimodality clinical examination of the patients involving provocative tests and echocardiography is recommended to be performed both preoperatively and postoperatively.     

Development of intracellular calcium responses to depolarization and to kainate and N-methyl-D-aspartate in cultured mouse hippocampal neurons.

We have investigated the initial appearance of voltage-gated Ca channels and kainate- and NMDA-type glutamate receptors in cultured embryonic mouse hippocampal neurons. The Ca-dependent fluorescence change of the dye fura-2 was used as a sensitive assay for the presence of functional channels and receptors. Expression of functional NMDA receptors was observed on some hippocampal neurons as early as E14. By the equivalent of E15-16, 40-50% of cells responded to Ko-depolarization (50 mM), indicating the presence of functional voltage-gated Ca channels, approximately 20% of cells responded to kainate (50 microM), and just under 20% responded to NMDA (50 microM; in the presence of glycine and strychnine). By the equivalent of the end of the embryonic period 70-80% of cells responded to all 3 stimuli. As approximately 20% of cells in these cultures are glia, these data indicate that by the time of birth close to 100% of neurons express functioning kainate and NMDA receptors, and voltage-gated Ca channels. Increases in [Ca2+]i in embryonic neurons after application of NMDA were sensitive to APV and to external Mg, as are responses in mature neurons. The IC50 for block by external Mg of the [Ca2+]i increase induced by NMDA was 130 microM, and there was a slight positive correlation between the amplitude of the response to NMDA and sensitivity to external Mg.     

Recurrent vestibulopathy: support for a viral etiology

Over an 18-month period, mother, father and child were seen with dizziness. The mother had Ramsay Hunt syndrome prior to developing recurrent vestibulopathy. A viral cause for recurrent vestibulopathy is suggested.