The Routine Use of Echoencephalography in the Diagnosis of Intracranial Masses

Ultrasonic echoes can be detected from interfaces within the body. This principle has been applied to the examination of the cranial contents by the procedure of echoencephalography. The presence of a unilateral intracranial mass was correctly predicted by this technique in 30 out of 33 cases. The method of examination is simple, harmless, painless and rapid. Its general adoption as an aid in diagnosis of intracranial lesions, particularly in acute head injuries, is recommended.     

The C-terminal domain of eukaryotic protein synthesis initiation factor (eIF) 4G is sufficient to support cap-independent translation in the absence of eIF4E.

The foot and mouth disease virus, a picornavirus, encodes two forms of a cysteine proteinase (leader or L protease) that bisects the EIF4G polypeptide of the initiation factor complex eIF4F into N-terminal (Nt) and C-terminal (Ct) domains. Previously we showed that, although in vitro cleavage of the translation initiation factor, eIF4G, with L protease decreases cap-dependent translation, the cleavage products themselves may directly promote cap-dependent protein synthesis. We now demonstrate that translation of uncapped mRNAs normally exhibits a strong requirement for eIF4F. However, this dependence is abolished when eIF4G is cleaved, with the Ct domain capable of supporting translation in the absence of the Nt domain. In contrast, the efficient translation of the second cistron of bicistronic mRNAs, directed by two distinct Internal Ribosome Entry Segments (IRES), exhibits no requirement for eIF4E but is dependent upon either intact eIF4G or the Ct domain. These results demonstrate that: (i) the apparent requirement for eIF4F for internal initiation on IRES-driven mRNAs can be fulfilled by the Ct proteolytic cleavage product; (ii) when eIF4G is cleaved, the Ct domain can also support cap-independent translation of cellular mRNAs not possessing an IRES element, in the absence of eIF4E; and (iii) when eIF4G is intact, translation of cellular mRNAs, whether capped or uncapped, is strictly dependent upon eIF4E. These data complement recent work in other laboratories defining the binding sites for other initiation factors on the eIF4G molecule.     

Effect of anoxia and reoxygenation on antioxidant enzyme activities in immortalized brain endothelial cells

Summary The effects of anoxia and reoxygenation on major antioxidant enzyme activities were investigatedin vitro in immortalized rat brain endothelial cells (RBE₄ cells). A sublethal anoxic period of 12 h was assessed for RBE₄ cells using the neutral red uptake test. Anoxia markedly influenced the specific activity of catalase and superoxide dismutase, with no major effect on glutathione peroxidase or glutathione reductase. After 24 h postanoxia, the superoxide dismutase activity modulated by the presence or absence of oxygen returned to control value. Damage and recovery of RBE₄ immortalized rat brain endothelial cells in culture after exposure to free radicals and other oxygen-derived species provides a usefulin vitro model to study anoxia-reoxygenation trauma at the cellular level.     

Corticotrophin releasing factor,grooming and ingestive behavior

Corticotrophin releasing factor (CRF) decreases food intake after starvation and during the nocturnal feeding phase in rats. This decrease appears to be associated with CRF producing a marked increase in grooming. The effects of CRF on food intake and grooming are independent of its effects on the pituatary. CRF is a putative mediator of stress-induced anorexias.     

Babysitting behavior by age/sex classification in squirrel monkeys (Saimiri sciureus)

The aunting behavior in a captive group of 22 squirrel monkeys containing three infants was done in terms of the age/sex classification of those animals involved. The time course of the aunting phenomena and the type and intensity of the interactions between the mothers and the aunts were recorded. Males as well as females were observed to ascertain if the babysitters were sex specific. Observations were gathered before, during, and after a particular threat to any monkey who was carrying an infant. Three categories of protective behavior (protect, retreat, and nothing) were tabulated. The results indicated that most aunting and protection occurred between infant ages 2-1/2-5 weeks when the infants were growing rapidly but not as yet socially self-sufficient. Mothers protected infants the most against juveniles, then subadult males, and least against other adult females. Subadult males were occasionally observed to carry and protect older infants. Aunting behavior was discussed in terms of the selective pressures by which it may have evolved.     

Amylin.

Amylin is a 37 amino-acid peptide which is secreted from the pancreatic islets of Langerhans. It has major sequence homology with calcitonin gene related peptide. Amylin can precipitate out in these cells to form amyloid. Amylin is secreted by similar stimuli to those that secrete insulin. Amylin has a number of effects that may counteract the effect of secreted insulin, i.e., decreased second phase insulin secretion, increased hepatic glucose output, and inhibition of insulin effects on skeletal muscle. It must, however, be recognized that in many cases the doses necessary to produce these effects appear to be supraphysiological. The putative role of amylin in the hyperglycemia of aging and Type II diabetes mellitus therefore remains controversial. Amylin has a number of other effects including inhibition of osteoclastic activity, vasodilatation, anorectic effects and enhanced memory retention. This review postulates a role for amylin in the pathogenesis of a number of age-related changes.     

In vivo human somatic mutation: frequency and spectrum with age.

The number and molecular nature of in vivo mutations in relation to age was studied at the autosomal HLA-A locus in human lymphocytes. Mutant lymphocytes were isolated by immunoselection, cloned at limiting dilution and enumerated, and the HLA-A gene and other polymorphic gene loci on chromosome 6 were studied by Southern blotting to determine gene dosage and loss of heterozygosity. Results of 167 assays in 73 individuals showed that the total number of mutant lymphocytes increased significantly with age from a geometric mean frequency of 0.71 x 10(-5) in neonates to 6.53 x 10(-5) in elderly individuals. Analysis of rearrangement of T lymphocyte receptor beta or gamma chain genes gave a best estimate of 3.3% for the proportion of mutant lymphocytes detected which are clonally related. Molecular study of 434 mutants from 31 individuals showed no change on Southern blotting in 64.7%, gene deletion in 2.8% and mitotic recombination in 32.5%. Two mutants due to gene conversion but no mutants due to non-disjunction were detected. The number of 'no change' and recombination mutants increased significantly with age. There was a significant difference between individuals in the proportion of mutants which resulted from mitotic recombination and the data suggested that the proportion was bimodally distributed. The point of crossing-over in recombination mutants was predominantly randomly distributed between the HLA-A locus and the centromere.