Regional levels of cyclic AMP in rat brain: pitfalls of microwave inactivation.

Techniques of in-vivo microwave irradiation to inactivate brain enzymes in rats were varied as to exposure configuration and output power. The rate at which metabolism was stopped was studied in various regions of the rat brain, using changes in levels of cyclic AMP and phosphodiesterase activity. Exposure times required to obtain stabilized levels of cyclic AMP varied in different brain regions, i.e., hypothalamus, cortex and cerebellum. Levels of cyclic AMP in selective regions of the brain decreased as more rapid inactivation was achieved. The authors identify important sources of variability of present microwave inactivation systems and the need for improved control of signficant microwave parameters.     

Ecophysiological investigations on lichens of the Negev desert

Summary Previous publications have reported on investigations of CO₂ exchange in the desert lichenRamalina maciformis both in its natural habitat in the Negev and in the laboratory. Utilizing laboratory data, net photosynthesis and dark respiration were expressed as mathematical functions of the most important environmental factors. Based on these relationships, a model is developed that allows one to predict CO₂ exchange of the plant. Input data are light intensity, temperature, and water content of the thallus, together with a measure of the rate of the seasonal change of photosynthetic and respiratory activity. The validity of the model is tested by comparing simulated daily courses of CO₂ uptake and release of the lichen with independent results of CO₂ exchange measurements conducted in the field during and after the condensation of dew. The sensitivity of the model is shown by simulating changes in the input data of temperature and water content of the lichen.This paper is dedicated to Dr. h.c. Oscar Klement on the occasion of his 80th birthday     

Subsoil gravel horizon and maize root growth

Summary A series of factoral experiments involving the effects of gravel concentration in the subsoil horizon, the effect of inter-gravel bulk density, the depth of the surface soil above the gravel horizon and the interaction between soil moisture regime and gravel concentration, on growth and development of maize roots were conducted in the greenhouse. Increasing sub soil gravel concentration decreased the total porosity and the available waterholding capacity. Though the root growth of maize seedlings was adversely affected by gravel concentration above 20 per cent, lower concentration of gravels had a beneficial effect on roots. The root development and the leaf concentration of N, P and K improved with increasing depth of surface soil above the gravel horizon. The symptoms of mechanical impedance, such as thickening of root tips and profuse branching behind the tip were commonly observed on the root axis penetrating the gravelly horizon. re]19750916     

Subtypes of Depression—Diagnosis and Medical Management

Depression is both a common and a greatly undertreated illness in the United States today. The focus of this review is a definition of the characteristics of four subtypes of depression which appear to be differentially sensitive to four different classes of medications. The tricyclic antidepressants should be used for patients with unipolar depression and vegetative symptoms. Lithium appears to be most effective for bipolar depressives. The monoamine oxidase (MAO) inhibitors are best used for patients with atypical depression. Antipsychotic medications appear to be useful for depressed patients with psychotic symptoms or agitation. Recent pharmacokinetic and biochemical data, including serum lithium levels, plasma tricyclic levels, and the predictive ability of pretreatment urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) levels are also reviewed.     

Possible occurrence of character displacement in the sympatric skates Raja erinacea and R. ocellata (Pisces: Rajidae)

Synopsis Raja erinacea and R. ocellata are sibling species which are positively correlated with each other by occurrence and numerical abundance. In sympatry the species undergo interactive segregation; R. erinacea feeds on a higher percentage of epifauna and R. ocellata feeds on a higher percentage of infauna.An isolated allopatric population of R. ocellata occurs in the Gulf of St. Lawrence which is phenotypically intermediate between the sympatric populations of R. erinacea and R. ocellata in characters related to feeding e.g. size, number of tooth rows in the upper jaw, and shape of the upper jaw. It appears probable that the allopatric population represents the morphological state of R. ocellata before it became sympatric with R. erinacea; divergence in size, number of tooth rows, and shape of the upper jaw between the two species developed after establishment of sympatry. These divergences in character traits, related to feeding, reduced competition between the two sympatric species and permitted the present wide overlap in their ranges.Character displacement is evidently rare in demersal fishes inhabiting the flat and soft bottoms of the northwestern Atlantic because the three other pairs of sibling species that occur there are parapatrically distributed and thus would not compete for resources. Raja erinacea and R. ocellata may have been restrained from establishing parapatry by another species pair of skates (R. senta and R. radiata) which have a complementary distribution and similar feeding habits of R. erinacea and R. ocellata but which occur in deeper water.     

Penetrating chest wound: a case report.

An unusual penetrating chest injury was caused by a ball-point pen. Because of apparent penetration of the heart, preparations were made for an emergency open-heart procedure before emergency thoracotomy was undertaken, with the pen still in situ. The pen had bruised the epicardium but had not penetrated the pericardial sac. After removal of the pen, the wound was closed and a chest tube left in place. Recovery, apart from minor degrees of basal atelectasis, pleural effusion and wound infection, was uneventful. The outcome was consistent with that associated with current aggressive management of penetrating chest injuries. Management is based on three approaches. The primary one is intercostal thoracostomy tube drainage and fluid and blood replacement. In cases of massive hemorrhage or air leak, thoracotomy is necessary. The third approach is to prevent post-traumatic pulmonary insufficiency by using fine, high-efficiency filters during blood transfusion, avoiding excessive administration of intravenous fluids, performing tracheostomy after prolonged endotracheal intubation, and using a volume respirator with positive end-expiratory pressure. The average mortality for penetrating wounds of the heart is 25%.     

Comparison of ribosomes from Coxiella burnetii and Escherichia coli by gel electrophoresis, protein synthesis, and immunological techniques.

Ribosomes and postribiosomal supernatant fluid (S-100) were isolated from Coxiella burnetii. The ribosomes functioned in polyuridylic acid-directed polyphenylalanine synthesis in the presence of S-100 from either C. burnetii or Escherichia coli. C. burnetii S-100 promoted translation with E. coli ribosomes. Antisera against E. coli elongation factor G and ribosomal proteins L7/L12 cross-reacted with rickettsial S-100 and ribosomes, respectively. Ribosomal proteins were analyzed by two-dimensional gel electrophoresis.