Prenatal diagnosis of GM1 gangliosidosis by detection of galactosyl-oligosaccharides in amniotic fluid with high-performance liquid chromatography.

Prenatal diagnosis of infantile GM1 gangliosidosis was accomplished by analyzing the galactosyl-oligosaccharides accumulating in amniotic fluid with high-performance liquid chromatography (HPLC) at 14 weeks gestation. The pattern of amniotic oligosaccharides was nearly identical with that in neonatal urine in GM1 gangliosidosis but the concentrations were about one-fiftieth of that in urine, necessitating a highly sensitive assay.     

The release of 3′:5′-cyclic monophosphate from the isolated perfused rat heart

Although basal release of cyclic AMP from isolated perfused rat hearts was not measurable, isoprenaline induced substantial release of the nucleotide, suggesting that in vivo the myocardium can contribute to plasma cyclic AMP. Anoxia also increased the amount of cyclic AMP released, but insulin and nicotinate alone or in combination had no effect.     

Avoiding biohazards in medical, veterinary and research laboratories

Personnel in medical, veterinary or research laboratories may be exposed to a wide variety of pathogens that range from deadly to debilitating. For some of these pathogens, no treatment is available, and in other cases the treatment does not fully control the disease. It is important that personnel in laboratories that process human or microbiological specimens follow universal precautions when handling tissues, cells, or microbiological specimens owing to the increasing numbers of individuals infected with hepatitis C and HIV in the US and the possibility that an individual may be asymptomatic when a specimen is obtained. Similar precautions must be followed in laboratories that use animal tissues owing to the possibility of exposure to agents that are pathogenic in humans. Personnel with conditions associated with immunosuppression should evaluate carefully whether or not specific laboratory environments put them at increased risk of disease. We offer here some general approaches to identifying biohazards and to minimizing the potential risk of exposure. The issues discussed can be used to develop a general safety program as required by regulatory or accrediting agencies, including the Occupational Safety and Health Administration.     

Glucocerebrosidase: reconstitution of activity from macromolecular components. (Short Communication)

Glucocerebrosidase activity was reconstituted in vitro from a soluble glycoprotein factor (P) and a particle-bound factor (C). The physiological significance of the system is discussed.     

Purified human liver acid beta-D-galactosidases possessing activity towards G(M1)-ganglioside and lactosylceramide.

Our studies with purified human liver acid beta-D-galactosidases (EC 3.2.1.23) indicate that 4-methylumbelliferyl beta-D-galactosidase and G(M1)-ganglioside beta-D-galactosidase activities are identical with lactosylceramidase II activity. Evidence for this includes co-purification of all enzyme activities by affinity chromatography to yield a single band on polyacrylamide-gel electrophoresis and coincident elution from Sepharose 6B of all three enzyme activities.     

UV-induced reversion of his4 frameshift mutations in rad6, rev1, and rev3 mutants of yeast

Summary The UV-induced reversion of two his4 frameshift alleles was much reduced in rad6 mutants of Saccharomyces cerevisiae, an observation that is consistent with the hypothesis that RAD6 function is required for the induction of all types of genetic alteration in misrepair mutagenesis. The reversion of these his4 alleles, together with two others of the same type, was also reduced in rev1 and rev3 mutant strains; in these, however, the extent of the reduction varied considerably with test allele used, in a manner analogous to the results in these strains for base repair substitution test alleles. The general features of UV-induced frameshift and substitution mutagenesis therefore appear quite similar, indicating that they may depend on related processes. If this conclusion is correct, greater attention must be given to integrating models which account for the production of nucleotide additions and deletions into those concerning misrepair mutagenesis.     

Conformational studies of Escherichia coli pyruvate oxidase

In this study the effects of experimental modifications of plasma membrane lipid lateral mobility on the electrical membrane properties and cation transport of mouse neuroblastoma cells, clone Neuro-2A, have been studied. Short-term supplementation of a chemically defined growth medium with oleic acid or linoleic acid resulted in an increase in the lateral mobility of lipids as inferred from fluorescence recovery after photobleaching of the lipid probe 3,3'-dioctadecylindocarbocyanide iodide. These changes were accompanied by a marked depolarization of the membrane potential from -51 mV to -36 mV, 1.5 h after addition, followed by a slow repolarization. Tracer flux studies, using 86Rb+ as a radioactive tracer for K+, demonstrated that the depolarization was not caused by changes in (Na+ + K+)-ATPase-mediated K+ influx or in the transmembrane K+ gradient. The permeability ratio (PNa/PK), determined from electrophysiological measurements, however, increased from 0.10 to 0.27 upon supplementation with oleic acid or linoleic acid. This transient rise of PNa/PK was shown by 24Na+ and 86Rb+ flux measurements to be due to both an increase of the Na+ permeability and a decrease of the K+ permeability. None of these effects occurred upon supplementation of the growth medium with stearic acid.