Involvement of nitric oxide in the deregulation of cytosolic calcium in cerebellar neurons during combined glucose-oxygen deprivation.

Nitric oxide (NO) has been proposed as a neuronal messenger molecule in hypoxic/ischemic cell injury (Nowicki et al., 1991; Trifiletti, 1992). We conducted studies in a model of combined glucose-oxygen deprivation using cultured rat cerebellar granule cells.

Age-related changes in the diurnal rhythm of CRH gene expression in the paraventricular nuclei.

A circadian rhythm secretion of corticotropin-releasing hormone (CRH) is thought to regulate the circadian pattern of secretion of adrenocorticotropic hormone and corticosterone. We have previously reported that the amplitude of the diurnal rhythm of serum corticosterone concentrations decreases in 17- to 20-mo-old rats. In the present experiment, we tested whether an age-related alteration in the daily rhythm and/or level of CRH mRNA in the paraventricular nuclei (PVN) occurs during middle age.

Glycogen phosphorylase activity and glycogen concentration in muscle of normal to overtly diabetic rhesus monkeys.

The effect of insulin to increase the activity of glycogen synthase (GS) in muscle has been well documented, however, the effect of in vivo insulin to inactivate glycogen phosphorylase (GP) has not been previously shown. To determine the effects of insulin on glycogenolysis in rhesus monkeys, GP and glycogen were determined in muscle samples obtained under basal fasting and insulin-stimulated conditions during a euglycemic hyperinsulinemic clamp in a group of 27 monkeys ranging from normal to overtly diabetic (NIDDM) and compared to GS activity previously examined. The diabetic monkeys had lower basal and insulin-stimulated glycogen concentrations compared to the normal and hyperinsulinemic monkeys (p < 0.

Determining the site and nature of DNA mutations with the cloned MutY mismatch repair enzyme.

The Escherichia coli MutY gene was cloned into a modified pET-11 plasmid which was then transfected into an E.coli HMS174 host for overproduction of the MutY mismatch repair (MR) enzyme. Approximately 30-50% of the total cellular protein in the transformed HMS174 cells was isopropyl-beta-D-thiogalactoside-induced MutY protein, as estimated from the staining intensity on an SDS-PAGE gel following electrophoresis.

Stabilization of the tetrameric structure of human and bovine hemoglobins by pseudocrosslinking with muconic acid.

In previous studies mono-3,5-dibromosalicyl-fumarate was used to introduce an intramolecular crosslink (pseudo-crosslink) in the beta cleft between hemoglobin beta subunits. Sedimentation velocity analysis indicated that the product had a mean molecular weight indicating a tetramer with low dissociability. The product had a P50 higher than that of native hemoglobin and a plasma retention time in the rat of about 3 h, i.

Self-organization in computer simulated selective systems.

In certain biologic systems, the signal selects functional or numerical expansion of the recognizing elements. Examples of these systems include the immune system, brain cortex, and evolution. One common feature of these Darwinian-type systems is degenerate recognition, in which one signal can recognize several different elements, with different affinities and consequences.

Distance distributions from the tyrosyl to disulfide residues in the oxytocin and [Arg8]-vasopressin measured using frequency-domain fluorescence resonance energy transfer.

We have examined the fluorescence intensity decays of oxytocin and [Arg8]-vasopressin resulting from the single tyrosyl residue in each peptide, and the intensity decay of the Asu1,6-analogues in which the disulfide bridge is substituted by a CH2-CH2 bridge. Viscosity-dependent steady state and intensity decay measurements indicated that fluorescence resonance energy transfer (FRET) from tyrosyl phenol to the disulfide bridge is responsible for the decrease in fluorescence relative to the Asu-analogues. The frequency-domain phase and modulation data for the tyrosyl donor were interpreted in terms of fluorescence resonance energy transfer (FRET) to the weakly absorbing disulfide bridge and a distribution of donor-to-acceptor distances.

Hsp47 and other ER-resident molecular chaperones form heterocomplexes with each other and with collagen type IV chains.

Collagen type IV is a genetically distinct secretory protein that constitutes a major component of the basement membranes. Despite the differences between collagen types I and IV, it appears that collagen IV alpha-chain translation/translocation through the ER should follow similar pathways to those established for procollagen I. Using a collagen IV-producing mouse teratocarcinoma cell line, we sought to determine if evolving nascent chains of collagen IV are associated with Hsp47 and other ER-resident molecular chaperones.

Lyme disease surveillance in Maryland, 1992.

The incidence of Lyme disease (LD) reported to the Maryland Department of Health and Mental Hygiene during 1992 was 6.5/100,000 population, ranging from 29.3 cases/100,000 on the Eastern Shore (74.

Tumor necrosis factor alpha mediates the antitumor effect of combined interleukin-2 and whole body hyperthermia.

Combined whole body hyperthermia (WBHT) and interleukin-2 (IL-2) significantly reduces the growth rate of subcutaneous 10 day MCA-105 tumors in C57BL/6 mice, but not in 3-day tumors. Others have shown that macroscopic tumors show reduced growth with tumor necrosis factor alpha (TNF alpha) therapy compared with microscopic tumors. We sought to determine if the antitumor effect of combined WBHT+IL-2 is mediated by TNF alpha.

Construction and immunogenicity of Salmonella typhimurium vaccine vectors that express HIV-1 gp120.

Since the human immunodeficiency virus (HIV-1) is transmitted either parenterally or sexually, both mucosal and systemic immune responses may be required to provide protective immunity. Attenuated Salmonella vectors expressing heterologous antigen can stimulate responses in both compartments. To evaluate the utility of Salmonella vectors as an HIV-1 vector vaccine, a gene expression cassette encoding recombinant HIV-1 gp120 (rgp120) was integrated into the hisOGD locus of Salmonella typhimurium aroA strain, SL3261 (SL3261::120).

Membrane skeleton restraint of surface shape change during fusion of erythrocyte membranes: evidence from use of osmotic and dielectrophoretic microforces as probes.

The role of the spectrin-based membrane skeleton in cell fusion was studied by following the condition-dependent diameter versus time expansion signature of the fusion zone in electrofused pairs of erythrocyte ghost membranes. Previous work showed that the presence of the dielectrophoresis-inducing alternating electric field, which is used to bring membranes into contact through pearl chain formation, had a detectable promoting effect on fusion zone expansion. Two new dielectrophoresis protocols were used in the present work to utilize this externally generated and controllable microforce field to probe the forces intrinsic to the system that drives the expansion of the fusion zone.

Immune responses to novel Escherichia coli and Salmonella typhimurium vectors that express colonization factor antigen I (CFA/I) of enterotoxigenic E. coli in the absence of the CFA/I positive regulator cfaR.

An asd-stabilized plasmid carrying enterotoxigenic Escherichia coli cfaABCE genes was constructed and called pJGX15C-asd+. Expression of colonization factor antigen I (CFA/I) by this plasmid occurs independently of the cfaABCE positive regulator cfaR in attenuated Salmonella delta aro delta asd strain H683 and nonpathogenic laboratory E. coli asd strain chi 6212.

Levels of superoxide dismutase mRNA in rat lens: effect of aging.

Superoxide dismutase, the enzyme catalyzing the dismutation of O2.- to H2O2 is known to be present in various ocular and nonocular tissues. In this communication we have determined the gene expression of this enzyme in rat lenses.

A fluorimetric liquid chromatographic method for the determination of propranolol in human serum/plasma.

A simple, rapid, and sensitive fluorimetric-high-performance liquid chromatographic method for the determination of propranolol in human serum/plasma has been developed, without the need for solvent extraction. The procedure required 200 microliters of serum/plasma, and the addition of 1 ml of acetonitrile for protein precipitation followed by vortexing and centrifugation at 10 000 g. The clear supernatant was evaporated to dryness under a stream of nitrogen at 50-60 degrees C, the residue was reconstituted in 100 microliters of methanol, and a 90 microliters portion was injected onto the high-performance liquid chromatograph for propranolol quantitation.

In vitro and in vivo antibiotic susceptibilities of ELB rickettsiae.

The activities of doxycycline, rifampin, chloramphenicol, and erythromycin against ELB rickettsiae (Rickettsia azadi) were determined by dye uptake and plaque assays. Plaque formation in Vero cells was inhibited by 0.12 microgram of doxycycline per ml.

Escherichia coli DNA topoisomerase III is a site-specific DNA binding protein that binds asymmetrically to its cleavage site.

The binding of DNA topoisomerase III (Topo III) to a single-stranded DNA substrate containing a strong cleavage site has been examined. The minimal substrate requirement for Topo III-catalyzed cleavage has been determined to consist of 7 bases; 6 bases 5' to the cleavage site and only 1 base 3' to the site. Nuclease P1 protection experiments indicate that the enzyme also binds to its substrate asymmetrically, protecting approximately 12 bases 5' to the cleavage site and only 2 bases 3' to the cleavage site.

Thrombosis and the pharmacology of antithrombotic agents.

Objective: To provide an overview of the current state of knowledge regarding the physiology of hemostasis, the pathophysiology of thrombosis, and the pharmacology of antithrombotic agents.

Data Sources: A MEDLINE search was conducted to identify pertinent literature published since 1984. Recently published textbooks devoted to the subjects of hematology, hemostasis, and thrombosis also were reviewed, particularly their bibliographies.

The membrane skeleton of acetylcholine receptor domains in rat myotubes contains antiparallel homodimers of beta-spectrin in filaments quantitatively resembling those of erythrocytes.

I used immunogold labeling and quick-freeze, deep-etch, rotary replication to characterize the membrane skeleton at regions with high concentrations of acetylcholine receptor domains in receptor clusters of cultured rat muscle cells. This membrane skeleton consists of a network of filaments closely applied to the cytoplasmic membrane surface. The filaments are specifically decorated by immunogold labeling with a monoclonal antibody, VIIF7, that recognizes an isoform of beta-spectrin colocalizing with acetylcholine receptors.

Effects of homelessness on the quality of life of persons with severe mental illness.

Objective: This study assessed the relationship between homelessness and specific quality-of-life problems for persons with severe and persistent mental illness.

Methods: The objective and subjective quality of life of 106 homeless persons with severe mental illness who lived on the streets or in shelters in Baltimore was compared with that of 146 domiciled persons with severe mental illness who lived in the community.

Results: Objective and subjective quality of life of the homeless subjects was clearly worse than that of the domiciled group in the areas of living situation, family and social relations, employment, daily activities, and legal and safety problems.

Contribution of biofilm bacteria to the contamination of the dental unit water supply.

The authors studied the contribution of bacterial biofilm to the contamination of the dental unit water supply, as well as the effects of flushing and sodium hypochlorite treatment on reducing the number of contaminants. This study demonstrated that biofilm in the dental tubing was the primary source of contaminated water delivered by dental units.

Dream busters ... clinic income.

In summary, the best clinical education occurs in a setting of exemplary patient care. The critical factor is quality--not just technical quality, but those features by which patients judge quality. Commitment to service should be enhanced and barriers should be minimized in order to achieve efficient and personalized patient care.

In vivo analysis of straight-chain and branched-chain fatty acid biosynthesis in three actinomycetes.

The starter units for branched-chain and straight-chain fatty acid biosynthesis was investigated in vivo in three actinomycetes using stable isotopes. Branched-chain fatty acids, which constitute the majority of the fatty acid pool, were confirmed to be biosynthesized using the amino acid degradation products methylbutyrl-CoA and isobutyrl-CoA as starter units. Straight-chain fatty acids were shown to be constructed using butyrl-CoA as a starter unit.

Differential up-regulation of HLA class I molecules on neuronal and glial cell lines by virus infection correlates with differential induction of IFN-beta.

Adult neurons normally lack the expression of MHC class I molecules, which has implications on virus clearance from the central nervous system. The author previously demonstrated that HLA class I up-regulation in measles virus (MV)-infected glial cells is primarily mediated by IFN-beta. In contrast, this study demonstrates that MV-infection of the neuronal cell lines IMR-32 and CHP-126 fails to up-regulate HLA class I expression, which was associated with an inability of MV to induce IFN-beta in the neuronal cell lines.