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PubMed1987

Neurologic abnormalities and recovery of human immunodeficiency virus from cerebrospinal fluid.

Infectious human immunodeficiency virus (HIV) was recovered from 30 of 48 cerebrospinal fluid specimens from seropositive persons with and without neurologic symptoms or disease. Of 16 patients with only neurologic problems or other HIV-related conditions, but not the acquired immunodeficiency syndrome (AIDS), 11 had virus recovered; over half of those with AIDS also had virus isolated. Patients with headache or altered mental status had the highest recovery rate of HIV from cerebrospinal fluid. Although virus was primarily found in patients with detectable neurologic disease, it was also isolated from 5 of 8 patients with normal neurologic examinations. Two of these patients had fever alone. The presence of virus in cerebrospinal fluid did not necessarily correlate with isolation of virus from the serum. These findings suggest that HIV may at times replicate preferentially in the brain and that its presence may not immediately cause neurologic signs or symptoms.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Diallel genetic analysis of the elements of paradise fish's (Macropodus opercularis L.) behavior in familiar and novel situations.

Elements of the paradise fish's ethogram were recorded in 1 familiar and 3 different unfamiliar situations and the inheritance of these behavioral elements was investigated employing a five times replicated diallel cross between 3 inbred strains. A generalized Hayman Analysis of Variance and a Variance Covariance Analysis were performed to estimate genetic effects and parameters, such as, additive genetic variance, different sorts of dominance variance, reciprocal effects, direction and degree of dominance, ratio between the frequency of dominant and of recessive alleles, minimum number of effective factors and heritabilities, etc. Knowing the genetic architecture, we make inferences about the possible evolutionary past of the behavioral elements and explain why selection might favor certain types of paradise fish's behavior in particular circumstances. In several cases a possibility of "monogenic" inheritance emerged. We explain this finding and conclude that in a cross experiment where the inheritance of phenotypical units are investigated by employing only a few genetically different strains this result may be expected.

Alleles↗
PubMed1988

The aortic intima in organ culture. Response to culture conditions and partial endothelial denudation.

A culture technique for whole blood vessel wall that preserves an intact and regenerative endothelium has been developed. The retention of an intact endothelium allows careful observation of the tissue as it responds to culture conditions, responses that include a change of replication timing and the induction of particulate endocytosis. Complete and normal regeneration of the endothelium in explants has made possible evaluation of the differences between the regeneration of endothelial cell monolayers and regeneration of intima in vivo. From these comparisons it appears that the shorter induction time of endothelial migration and proliferation and the more rapid migration in endothelial cell monolayers are due to effects of the culture medium or plastic culture surface, while the higher than normal cell density found in the intima after wound recovery in vivo probably is due to the dynamics of the blood vessel itself. The ability to control cell-cell interactions on the cultured tissue has made possible the investigation of gap junction-mediated metabolic interactions in regenerating intima. Results indicate that the disruptive effects of intimal regeneration do not depend on or produce an obvious change in junction-mediated nucleotide transfer between endothelial cells.

Animals↗
PubMed1985

Nitroderm TTS in exercise-induced angina pectoris--a randomized double-blind study.

Nitroderm TTS is a new transdermal delivery system for nitroglycerin, consisting of a self adhesive disc from which the drug diffuses into the skin at a predetermined rate through a microporous membrane. In an acute, randomized, double-blind, within-patient study, a TTS formulation releasing 10 mg of nitroglycerin over 24 hours (TTS 10) was compared with placebo and isosorbide dinitrate (ISDN) 20 mg slow-release. TTS 10, ISDN and placebo were given on 3 successive days, according to a 3 X 3 latin square design 3 times replicated, to 9 in-patients with coronary heart disease and stable exercise-induced angina pectoris. At rest, both TTS 10 and ISDN significantly lowered lying (p less than 0.05) and standing (p less than 0.01) systolic blood pressure as compared to placebo, but there was no difference between the 2 active treatments. On the symptoms-limited cycloergometric exercise test, carried out 4 hours post-dosing, both TTS 10 and ISDN significantly (p less than 0.05) improved exercise tolerance in respect to placebo. Treatments were well tolerated. In conclusion, both TTS 10 and ISDN, 4 hours post-dosing, are superior to placebo in improving exercise tolerance in patients with coronary heart disease and exercise-induced angina pectoris. The transdermal therapeutic system, allowing constant plasma nitroglycerin levels over 24 hours, has the advantage of once daily administration.

Adult↗
PubMedDate not supplied

Medical hypothesis: cardiovascular complications of diabetes mellitus-from glucose to insulin and back.

Vascular complications such as atheroma, hypertension and macroangiopathy are the leading causes of morbidity and mortality in diabetic patients. Epidemiological and clinical data linking hyperinsulinaemia to both hypertension and atherosclerosis are inconsistent. Hyperglycaemia is the distinguishing feature of diabetes and it seems a likely candidate for the poor cardiovascular outlook of diabetic patients. High blood glucose levels cause selective impairment of endothelium-dependent relaxation and delay cell replication time of cultured human endothelial cells. These effects of hyperglycaemia are reversed by a number of antioxidants, including superoxide dismutase, catalase and glutathione. Impaired endothelium-dependent vasodilation has been reported both in Type 1 and Type 2 diabetic patient. The evidence for a role of oxygen-derived free radicals in the pathogenesis of vascular diabetic complications can be summarized as follows: 1) glucose can auto-oxidize generating oxygen derived free radicals; 2) elevated levels of oxygen derived free radicals are found in red blood cells, plasma and retina of diabetic animals and patients, and correlate with metabolic control; 3) endogenous antioxidants are all decreased in diabetic tissues and blood; and 4) treatment with different antioxidants may improve many of the metabolic abnormalities reported to occur in diabetic patients. The use of antioxidants to reduce the risk of coronary heart disease in diabetes should await the results of randomized trials with these drugs in the primary and secondary prevention of coronary disease.

Blood Glucose↗
PubMed1983

ARS replication during the yeast S phase.

A 1.45 kb circular plasmid derived from yeast chromosome IV contains the autonomous replication element called ARS1. Isotope density transfer experiments show that each plasmid molecule replicates once each S phase, with initiation depending on two genetically defined steps required for nuclear DNA replication. A density transfer experiment with synchronized cells demonstrates that the ARS1 plasmid population replicates early in the S phase. The sequences adjacent to ARS1 on chromosome IV also initiate replication early, suggesting that the ARS1 plasmid contains information which determines its time of replication. The times of replication for two other yeast chromosome sequences, ARS2 and a sequence referred to as 1OZ, indicate that the temporal order of replication is ARS1 leads to ARS2 leads to 1OZ. These experiments show directly that specific chromosome regions replicate at specific times during the yeast S phase. If ARS elements are origins of chromosome replication, then the experiment reveals times of activation for two origins.

DNA Replication↗
PubMed1989

Activation and repression of a beta-globin gene in cell hybrids is accompanied by a shift in its temporal replication.

To investigate whether a switch in the transcriptional activity of a gene is associated with a change in the timing of replication during the S phase, we examined the replication timing of the beta-globin genes in two different types of somatic cell hybrids. In mouse hepatoma (Hepa 1a) x mouse erythroleukemia (MEL) hybrid cells, the beta-globin gene from the MEL parent is transcriptionally inactivated and is later replicating than in the parental MEL cell line. In human fibroblast (GM3552) x MEL hybrid cells, the human beta-globin gene is transcriptionally activated, and all of the sequences within the human beta-globin domain (200 kilobases) we have examined appear to be earlier replicating than those in the parental fibroblast cell line. The chromatin configuration of the activated human beta-globin domain in the hybrids is relatively more sensitive to nucleases than that in the fibroblasts. Furthermore, major nuclease-hypersensitive sites that were absent in the chromatin flanking the distal 5' region of the human beta-globin gene cluster in the parental fibroblast cell line are present in the transcriptionally activated domain in the hybrid cell line. These results suggest that timing of replication of globin genes has been altered in these hybrid cells and thus is not fixed during the process of differentiation.

Animals↗
PubMed1988

Timing of chromosomal replication in Escherichia coli.

We have previously shown that certain mutations in the dnaA and recA genes of Escherichia coli perturb initiation of chromosomal replication so that all origins present are not initiated simultaneously. In this work, several genes whose protein products are involved in initiation of replication have been investigated for their effects on the synchrony of initiation. Some of the mutants (dnaC2, rpoC907, dam3) were found to have the asynchrony phenotype. Also, dnaA(Ts) mutations were shown to be dominant over dnaA+ in terms of initiation synchrony. The mechanism leading to the asynchronous phenotype is discussed.

Bacterial Proteins↗
PubMed1986

Zinc oxide to induce molt in layers.

The effects of the addition of Zn as ZnO to diets to induce molt were evaluated against a fasted control. Experiment 1 involved 315 Leghorn hens, 15 months old, randomly distributed among five treatments, each replicated seven times with 9 hens per replicate. Hens fasted for 10 days were compared with hens fed diets to which ZnO was added at 10,000, 5,000, or 2,500 ppm for 7, 14, or 21 days. No significant differences were observed among treatments for days to return to 50% production, hen-day and hen-housed production, egg weight, grams egg per hen-day, grams of feed per gram egg, mortality, or Haugh units during the 22-week experimental period. Experiment 2 involved 420 Leghorn hens, 18 months old, randomly distributed among five treatments, each replicated seven times with 12 hens per replicate. Treatments involved fasting for 10 days or feeding diets with 10,000, 5,000, or 2,500 ppm ZnO fed for 7, 14, or 21 days. Hens fasted and hens fed diets with 10,000 ppm ZnO at the start of the experiment ceased production in significantly less time (4.6 to 6 days) than hens fed 5,000 ppm ZnO (14.3 to 14.9 days); however, days to return to 50% production from the start of the experiment did not differ among treatments. Feed consumption and feed cost per hen day during molt were lowest (P less than .05) in the fasted hens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Heterochromatin associated with active versus inactive centromeres of mouse replicates at different times.

A subline of mouse L-cells carries a dicentric chromosome in which one centromere always separates prematurely. This centromere is not involved in the dynamics of chromosome migration and is considered inactive. By use of anti-BRdU antibody binding to BRdU-treated chromosomes it is shown that the pericentric constitutive heterochromatin associated with the prematurely separating centromere replicates earlier than its counterpart associated with the active centromere and even before several euchromatic regions in the genome. These results point to a possible mechanism by which dicentric chromosomes segregate equationally.

Animals↗