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Biomedical subjects

R Levin

Publications and source records attributed to R Levin.

At least 91 records · Page 5Linked to original sources
PubMed1995

Relations of oral imagery to thought disorder in subjects with frequent nightmares.

Oral imagery was examined in the Rorschach protocols of 60 female subjects, 30 who experienced at least one nightmare per week and 30 who had no more than one nightmare in the past year. Mean number of oral responses did not differ between the groups. In subjects with nightmares, Rorschach orality was significantly related to many personality measures, including state and trait anxiety, Beck Depression Inventory scores, five subscales of a schizotypy inventory, the Rorschach penetration score, and two measures of pathological thinking on the Rorschach. In the 30 subjects without nightmares, the number of significant correlations did not exceed that expected by chance. The results are discussed within the context of empirical and theoretical reports about the links between the oral personality and pathological behavior.

Adolescent↗
PubMed1994

Effect of cromakalim and pinacidil on 86Rb efflux from guinea pig urinary bladder smooth muscle.

86Rb efflux assay was used to investigate the effect of cromakalim, pinacidil and P1075 in guinea pig urinary bladder strips. The type of K channel opened by cromakalim and pinacidil was determined using specific K channel blockers through 86Rb efflux assay in detrusor strips. Cromakalim, pinacidil and P1075 all three potassium channel openers (PCOs) evoked a concentration-dependent increase in 86Rb efflux in bladder strips. This increase in isotope release was inhibited by pretreatment of bladder with 10 and 30 microM glibenclamide suggesting that both cromakalim and pinacidil interact with ATP-sensitive K channels (KATP). Further, an increase in basal 86Rb efflux was observed when 2-deoxy-D-glucose was substituted for glucose together with 0.24 micrograms/ml of oligomycin (known to lower intracellular ATP) indicating the presence of KATP channels in bladder smooth muscle. Charybdotoxin and apamin, blockers of large and small conductance Ca(2+)-dependent K channels, were found not to be involved in the action of these PCOs in bladder strips. alpha-Dendrotoxin, known to block voltage-dependent K channels, slightly reduced pinacidil-induced 86Rb release without affecting cromakalim-induced 86Rb efflux. The present studies show that ATP-sensitive K channels are present in guinea pig urinary bladder and that cromakalim and pinacidil act by opening these ATP-sensitive K channels in detrusor strips.

Adenosine Triphosphate↗
PubMed1994

"Salvage" therapy?

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Breast Neoplasms↗
PubMed1992

Neuronal cell cultures as a model for assessing neurotoxicity induced by encephalitic viruses.

Primary dispersed and organotypic cultures were prepared from selected brain areas and spinal cords of rat (Sprague-Dawley) and mouse (SJL/OLA(F) Ness-Ziona) fetuses and neonates. Following fiber regeneration, synapse formation and myelination, cultures were infected with one of the following viruses: Rabies CVS-21 strain, Sindbis Alphavirus, West-Nile Flavivirus and Theiler Murine Encephalomyelitis virus. Light and electron microscopical studies showed clear differences in the target cells for virus infection; time of viral replication and in the intensity and specificity of the cytopathic effects induced by these viruses. Thus, Sindbis and Theiler viruses induced severe cytotoxicity and demyelination due to rapid viral replication in both neurons and all glial cell types. Rabies and West-Nile viruses, on the other hand, replicated mainly in neurons and at a much slower rate, causing only mild damage to the cells and the myelin sheath. A very specific alignment of West-Nile virions was observed along the interperiod lines of the myelin sheath in several myelinated axons. This peculiar arrangement of the virions, entrapped between the myelin lamellae may lead to a novel concept in the understanding of viral infection.

Animals↗
PubMed1991

Spinal cord slices with attached dorsal root ganglia: a culture model for the study of pathogenicity of encephalitic viruses.

We describe here a culture system for long-term growth of organotypic slices of spinal cord, with attached dorsal root ganglia (DRG) derived from 13-14 day mouse fetuses. This is a unique in vitro tool in which both central and peripheral nervous tissue grow and differentiate in culture to become heavily myelinated. During cultivation the slices and the ganglia become flattened so as to allow microscopical and immunocytochemical staining. When both central and peripheral myelin had been formed (usually around the third week of cultivation), cultures were infected with 5 x 10(6) PFU of West Nile Virus (WNV). Progeny virions appeared first in about 10% of the neurons and were subsequently observed between lamellae in the central myelin sheath of several axons. Such viral arrangement in relation to myelin membranes, might provide a novel concept for a possible mechanism underlying slow viral infection.

Animals↗
PubMed1991

The risk of lead toxicity in homes with lead paint hazard.

While lead paint has long been known to be a major source of lead poisoning, only a few small epidemiologic studies have attempted to assess directly the relative risk of lead poisoning due to the presence of lead paint. Using data from over 200,000 screening tests of children in the city of Chicago performed between 1976 and 1980, the relative risks can be quantified for children living in a major urban area. Lead paint was found to be a significant predictor of the probability of a child having lead toxicity. As expected, the reduction in leaded gasoline sales during the period reduced mean blood lead levels and increased the percentage of lead toxic children whose toxicity could be attributed to paint lead. Poisson regression models indicated that with the elimination of leaded gasoline, the relative risk of lead toxicity given lead paint exposure was 5.70 (95% CI, 4.13-7.86) during the winter and fall. The relative risk rose to 12.81 (95% CI, 7.33-22.4) in the spring and 15.8 (95% CI, 8.90-28.1) in the summer, probably due to increased exposure to window wells.

Bayes Theorem↗
PubMed1991

A non-bronchoconstrictor, bacteriostatic preservative for nebuliser solutions.

We have studied the bacteriostatic and airways effects of the preservatives chlorocresol and chlorbutol, to assess if they may be safely used in nebuliser solutions. The bacteriostatic study was carried out according to standard techniques, and the preservatives were able to inhibit the growth of a range of bacteria and yeasts for a period of 28 days. The airways effects were studied in eight asthmatic subjects, who were challenged with either the preservatives or saline (as placebo). Pulmonary function was followed as FEV1 for 60 min after inhalation, and there was no change in FEV1 following inhalation. We conclude that these preservatives may be used safely in nebuliser solutions.

Adult↗
PubMed1991

Concordance between two measures of dream bizarreness.

To assess the level of concordance between two published measures of dream bizarreness, 100 randomly selected dreams from 93 college students were scored for primary process using the Auld, Goldenberg, and Weiss scale and for dream distortion using Zepelin's scale. This analysis yielded a strong relationship between these measures, indicating adequate concurrent validity for the content analysis of the construct of dream bizarreness.

Adult↗
PubMed1990

Different pathogenicity of encephalitic togaviruses in organotypic cultures of spinal cord slices.

The pathogenicity of two encephalitic Togaviruses, Sindbis virus (SV), an alphavirus, and West Nile virus (WNV), a flavivirus, was studied in organotypic cultures of fetal mouse spinal cord slices grown in roller tubes. After about 3 weeks in vitro, during which time the cultures became abundantly myelinated, they were infected either by 5 X 10(5) PFU SV or by 5 X 10(6) PFU WNV per culture. The viruses caused different patterns of cytopathogenicity: SV induced severe cytotoxicity in all glia cells and neurons with concomitant demyelination within 48 hr. In contrast, WNV, even 4 days after infection, caused only mild cytopathic effects mainly to neurons and astrocytes and a slight degree of damage to the myelin sheath. A most remarkable finding was the entrapment of WNV particles in the interperiod lines of the myelin sheaths. Treatment of cultures with mouse alpha and beta interferon prior to their infection with either virus protected the cultures from any viral damage. Long-term exposure of non-infected control organotypic cultures of fetal spinal cord slices to mouse interferons had no significant effect on neuronal and glial differentiation, and myelin formation.

Animals↗
PubMed1990

West Nile virions aligned along myelin lamellae in organotypic spinal cord cultures.

Organotypic spinal cord cultures infected with West Nile Virus (WNV) exhibited a remarkable arrangement of virions among lamellae of the myelin sheath. Virions were first observed in neurons and only at day 4 after infection appeared within the myelin lamellae. Virions were observed only in the central myelin, aligned along the interperiod lines and therefore attached to the outer side of the oligodendrocyte membrane. In spite of this peculiar location of the virions, their presence was not associated with severe damage to the axon or to the myelin sheath. The causes of the formation of this viral pattern, its morphological features, and the role which it might have in viral infection in vivo are considered.

Animals↗
PubMed1990

Serologically defined linear epitopes in the E2 envelope glycoprotein of Semliki Forest virus.

A set of 41 overlapping peptides, representing the complete sequence of SFV-E2 protein were synthesized and analyzed in the ELISA test against murine anti-SFV sera. No single peptide was recognized by all antisera. Eight peptides were found to be highly reactive with hyperimmune anti-SFV sera. Six out of the eight peptide sequences coincide with the most hydrophilic regions of SFV-E2. Out of these, four peptides (amino acid positions 16-35, 61-80, 166-185, 286-305) that contain the least number of alphavirus conserved residues were selected. This panel constitutes the minimal number of peptides necessary and sufficient for specific recognition of hyperimmune mouse anti-SFV sera.

Antigens, Viral↗
PubMed1990

Effect of specific amino acid groups on renal hemodynamics in humans.

The effect of specific amino acid groups on renal hemodynamics was examined in seven healthy young volunteers. Each subject received a 3-h intravenous infusion according to one of the following protocols: study 1, gluconeogenic amino acids (Arg, Gly, Pro, Cys, Met, Ser); study 2, alanine alone; study 3, branched-chain amino acids (BCAA, Leu, Ile, Val); or study 4, 0.9% saline. The rise (40-60% above base line) in total plasma amino acid concentration was similar in studies 1-3; no change was observed in study 4. During study 1, glomerular filtration rate (GFR) rose by 16% (from 98 +/- 6 to 114 +/- 8 ml.1.73 m-2.min-1, P less than 0.01), and renal plasma flow (RPF) rose by 28% (from 496 +/- 47 to 638 +/- 70 ml.1.73 m-2.min-1, P less than 0.01). After alanine (study 2) and BCAA (study 3) infusion, there was a slight, although not significant, rise in GFR and RPF; during saline infusion (study 4), GFR and RPF remained unchanged. Plasma insulin and growth hormone did not change significantly in any study protocol. Plasma glucagon rose significantly by 30% in study 1 (from 117 +/- 10 to 151 +/- 13 pg/ml, P less than 0.05) but did not change in studies 2-4. In summary, infusion of mixed gluconeogenic amino acids increases both GFR and RPF, and neither alanine nor BCAA infusion caused a consistent alteration in renal hemodynamics.

Adult↗