Characterization of hepatitis B virus (Dane particle)

Hepatitis B virions (Dane particles) were purified from the sera of chronic HBsAg carriers by consecutive rate-zonal and isopycnic centrifugations in sucrose gradients using HBsAg, HBcAg and endogenous DNA polymerase activities as specific markers. Purified Dane particles, radiolabelled with Na ¹²⁵I by the chloramine-T procedure, had a higher buoyant density in CsCl (1.28 g/cm³) than unlabelled particles (1.26 g/cm³) and an estimated sedimentation coefficient of 280 s. ¹²⁵I-Dane particles were fully precipitated by anti-HBs and not by anti-HBc sera. Heavy and light density core particles were purified from heavy and light density populations of Dane particles and radioiodinated. The iodinated polypeptides of Dane particles and HBcAg were compared with those of the iodinated 22-nm form of HBsAg by SDS-PAGE. Iodinated Dane particles contained seven polypeptides with molecular weights of 18,000, 23,000, 26,000, 34,000, 43,000, 48,000 and 115,000. Heavy and light core particles contained three polypeptides with molecular weights of 18,000, 25,000 and 37,000.     

In vitro degradation of silk fibroin

A significant need exists for long-term degradable biomaterials which can slowly and predictably transfer a load-bearing burden to developing biological tissue. In this study Bombyx mori silk fibroin yarns were incubated in 1mg/ml Protease XIV at 37 degrees C to create an in vitro model system of proteolytic degradation. Samples were harvested at designated time points up to 12 weeks and (1) prepared for scanning electron microscopy (SEM), (2) lyophilized and weighed, (3) mechanical properties determined using a servohydraulic Instron 8511, (4) dissolved and run on a SDS-PAGE gel, and (5) characterized with Fourier transform infrared spectroscopy. Control samples were incubated in phosphate-buffered saline. Fibroin was shown to proteolytically degrade with predictable rates of change in fibroin diameter, failure strength, cycles to failure, and mass. SEM indicated increasing fragmentation of individual fibroin filaments from protease-digested samples with time of exposure to the enzyme; particulate debris was present within 7 days of incubation. Gel electrophoresis indicated a decreasing amount of the silk 25 kDa light chain and a shift in the molecular weight of the heavy chain with increasing incubation time in protease. Results support that silk is a mechanically robust biomaterial with predictable long-term degradation characteristics.     

New families of adhesion molecules play a vital role in platelet functions

Adhesion molecules play a crucial part in cell-matrix and in cell-cell interactions. These interactions, which are essential to the body's defense processes, involve adhesion molecules belonging to different families: integrins, immunoglobulins and selectins. Integrins are expressed by a large number of tissues, whereas other adhesion molecule families are restricted to a small number of cell types. A recent symposium dealt with the recruitment of circulating platelets at specific sites, their adhesion to extracellular matrix components and their activation by agonists leading to aggregation or attachment to other cells. These events, supporting hemostasis and thrombosis, involve integrins, selectins and other adhesion molecules. This report focuses on newly reported integrins (GPIa, GPIc, GPIIa), selectins (GMP-140) and GPIIIb, previously known as 'minor' surface oriented platelet glycoproteins. Major membrane glycoproteins such as GPIIb-IIIa (an integrin) and GPIb, which also play a vital role in platelet functions, have been extensively reviewed elsewhere.     

Phospholipid metabolism of herpesvirus-infected and uninfected rabbit kidney cells

The incorporation of labeled precursors into the phospholipids of uninfected rabbit kidney cells in stationary phase was studied with the following results: (1) Incorporation of ³²P into cytoplasmic phospholipids is rapid and reaches a plateau by 40 hr of incubation with the isotope; incorporation into the nuclear fraction, however, continues to increase linearly. (2) The different phospholipids become labeled at different rates. (3) The inner nuclear membrane fraction has a different phospholipid composition from the outer nuclear or the cytoplasmic fractions; it contains a significantly larger amount of sphingomyelin.     

An Association Between a Microsatellite Polymorphism at the DRD5 Gene and the Liability to Substance Abuse: Pilot Study

We have conducted a population-based association study of substance abuse and a microsatellite at the dopamine D5 receptor locus (DRD5) in a sample of European–American males and females with substance dependence (SA) or without any psychiatric disorder. Overrepresentation of the most frequent allele (148 bp) was found in males in the SA group (OR = 2.2, P= .02); this finding was reproduced in females (OR = 5.4, p< .001). The difference in the frequencies of this allele between SA males and SA females was statistically significant. The genotype coded in accordance with the dose of this allele correlated with substance abuse liability in males and females (stronger in females) and with novelty seeking in females. There was no evidence of correlation between the genotypes of spouses that could be induced by assortative mating for the liability to substance abuse. The data suggest that the DRD5 locus is involved in the variation and sex dimorphism of substance abuse liability.CEDAR is a consortium between St. Francis Medical Center and the University of Pittsburgh.     

Inconsistent expression of both centromeres of a dicentric Y chromosome in a child with ambiguous external genitalia.

A newborn child with ambiguous external genitalia had evidence of internal female development on the left and internal male development on the right. Blood chromosome analysis showed three cell types: 45,X; 46,XY with the Y being submetacentric and about twice the usual size with two 'centromeric' C bands; and 46,X,dic(Y). Chromosome studies from the skin, uterus, and Fallopian tube showed almost exclusively 45,X cells. This represents the second reported patient in whom two centromeres are inconsistently expressed though present as shown by two 'centromeric' C bands.     

Genetic counseling in ornithine carbamoyltransferase deficiency

Ornithine transcarbamylase (OTC) deficiency is an inborn error of urea cycle metabolism, responsible for lethal hyperammonemia in males and for severe symptoms in at least 20% of heterozygous females. The authors provide here additional data on the informativity of the protein loading test (PLT) for the detection of heterozygotes. They show that the risk of being a carrier for the mother of an affected boy falls from 2/3 a priori to only 1/8 if her PLT is negative. The risk for the mother of heterozygote girl falls from 1/2 a priori to 1/16 if her PLT is negative.     

Effects of social factors on adrenal weight and related physiology of Macaca fascicularis

Increased adrenal cortical activity and hypertrophy of adrenal glands associated with defeat and social subordination have been reported frequently in small mammals; these adrenal changes have been linked to impairments in immune response, glucose metabolism and reproductive performance. Similar studies in primates have produced variable results. The current study was undertaken to illuminate the effects of social status on the adrenal gland and to examine concurrent effects of social variables on other physiological systems in Macaca fascicularis, in an initial exploration of the hypothesis that high and low social status have different physiological consequences. Sixty adult male M. fascicularis were housed in social groups of n = 5, under either stable or unstable social conditions. It was found that subordinate animals had heavier adrenal glands and somewhat higher plasma glucose concentrations than dominants. In contrast, dominants had higher blood pressure and worsened atherosclerosis, under some conditions, than subordinates. These data appear to offer preliminary support for Henry and Stephen's hypothesis of differential arousal of dominant and subordinate animals.