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Biomedical subjects

D Nelson

Publications and source records attributed to D Nelson.

At least 307 records · Page 17Linked to original sources
PubMed1979

Histone deacetylation in nuclei isolated from hepatoma tissue culture cells. Inhibition by sodium butyrate.

Nuclei from hepatoma tissue culture (HTC) cells were isolated by standard methods and incubated in media commonly used for nuclease digestions (DNAase I and micrococcal nuclease) and for in vitro RNA synthesis. During the incubation, histones can be deacetylated from both control cells and cells treated with 6 mM sodium butyrate to enhance the levels of histone acetylation. Deacetylation of histone is much more apparent in nuclei isolated from sodium butyrate-treated cells. Inclusion of 6 mM sodium butyrate in the incubation medium effectively inhibits the endogenous deacetylase activity acting on histones H3 and H4, whereas sodium acetate at the same concentration has very little inhibitory effect.

Acetates↗
PubMed1979

Cardenolide analogues: 10--characterization of cardiac glycosides by chemical ionization mass spectrometry.

The potential of chemical ionization mass spectrometry for the characterization of naturally occurring and semi-synthetic cardiac glycosides has been investigated. Methane, isobutane and ammonia were used as reactant gases. With the exception of ouabain, the ammonia chemical ionization mass spectra of the cardiac glycosides examined in this work contained abundant [M + NH4]+ions and abundant fragment ions formed by cleavage of glycoside bonds. Ammonia chemical ionization mass spectrometry was found to provide a rapid and sensitive method for the characterization of the products of glycosidation reactions. In contrast, the methane and isobutane chemical ionization mass spectra of the cardiac glycosides, with the exception of ouabain, did not contain protonated molecular ions and did not contain abundant fragment ions above m/z 400.

Ammonia↗
PubMed1979

Pentothal protection for delay cerebral revascularization.

Thiopentone (20 mg/kg/bolus and 20 mg/kg/three hours) was effective in preventing infarction in five dogs with six hours of middle cerebral occlusion. Nine control animals sustained massive to large infarctions. Utilizing this regime therapeutic blood levels were rapidly attained for over 12 hours without side effects. From the experimental and human experience with focal cerebral ischaemia, there appears to be a finite grace period in which cerebral revascularization can be undertaken. In canine and primate models this time has been about five hours, following which the infarction process may not be reversible (Sundt et al. 1977, Laha et al. 1978). Seeking to prolong this grace period, thiopentone was selected as an ideal drug for this purpose, and its effect on the revascularized canine middle cerebral distribution was evaluated at six hours following embolectomy.

Animals↗
PubMed1979

Abnormal whole-body and cellular (erythrocytes) turnover of 22Na+ in normotensive relatives of probands with established essential hypertension.

1. Whole-body elimination rate of 22Na+ was decreased in normotensive or borderline first-degree relatives of hypertensive probands. 2. Whole-body potassium, exchangeable sodium and urine excretion of sodium, potassium and creatinine were similar in relatives and controls. 3. Erythrocyte net influx of 22Na+ was significantly increased in normotensive relatives. 4. Abnormal whole-body and cellular handling of sodium (22Na+) demonstrated in relatives indicates that this abnormality may have an important role in the development of essential hypertension in man.

Erythrocytes↗
PubMed1979

A correlation between nucleosome spacer region susceptibility to DNase I and histone acetylation.

Hepatoma tissue culture (HTC) cell nuclei were digested with either DNase I or micrococcal nuclease and the nucleohistone digestion products fractionated by gel electrophoresis or exclusion chromatography. Under appropriate conditions, gel electrophoresis demonstrates that for both nucleases, only cleavages within the nucleosome spacer regions and not within the nucleosome core lead to freely migrating nucleohistone particles. These particles consist of nucleosome cores, nucleosomes and nucleosome oligomers. Following DNase I digestion and fractionation by exclusion chromatography, analysis of the histones indicates a direct relationship between increased spacer region susceptibility to nuclease and increased nucleosomal histone acetylation. Evidently digestion sites outside the regions of DNA protected by core histones can reflect the degree of acetylation of core histones. Such a relationship is not found when micrococcal nuclease is used to digest the samples.

Acetylation↗
PubMed1979

Non-polio enterovirus activity in Wisconsin based on a 20-year experience in a diagnostic virology laboratory.

Laboratory test results, demographic information, and clinical data on 1364 patients who had specimens submitted to the Wisconsin State Laboratory of Hygiene and from whom non-polio enteroviruses were isolated during 1957--1976 were examined. Echoviruses (echo) and Coxsackievirus group B (CB) and group A (CA) were isolated from 719, 389, and 256 of the patients, respectively. Thirty-five different serotypes were identified in the 20-year period. The six most frequently occurring serotypes (echo 9, CB 5, echo 18, CB 2, CB 4, and echo 6) were associated with 57 per cent of all illnesses. The first three serotypes occurred in an epidemic-like manner whereas the next three appeared to be endemic. Eighty-eight per cent of all isolations were from patients whose illnesses began in July through October. The percentage of CA isolates obtained from adults was much smaller than the corresponding percentages seen with CB or echo. A majority of the non-polio enteroviruses were obtained from males. Central nervous system and gastrointestinal tract involvement was greatest with echo and CB 5 tract and lowest with CA and CB 1--4 illnesses. The highest frequency of respiratory tract involvement was with CA and echo 9 illnesses and rash was most frequent with CA illnesses. The highest frequency of hospitalization was with CB 5 patients.

Adolescent↗
PubMed1979

Laboratory-based surveillance of influenza virus in the United States during the winter of 1977-1978. I. Periods of prevalence of H1N1 and H3N2 influenza A strains, their relative rates of isolation in different age groups, and detection of antigenic variants.

Influenza A (H3N2) viruses were isolated from outbreaks and epidemics of disease during the period December 1977 to March 1978. For the last two months of this period, H1N1 strains of influenza A were also responsible for epidemics. In some regions (e.g., Hawaii) co-circulation of H1N1 AND H3N2 strains occurred, whereas in other regions (e.g., Wisconsin) isolation of H3N2 strains had almost ceased prior to isolation of H1N1 strains. Few influenza B isolates were reported. Analysis of the ages of patients from whom specimens were submitted for influenza virus isolation confirmed that, whereas H3N2 strains were isolated from persons of all ages, greater than 97 per cent of H1N1 isolates in six states analyzed were recovered from patients less than 26 years old, although specimens were tested from older persons who were ill during the period of prevalence of H1N1 influenza. The majority of H3N2 isolates tested by hemagglutinin-inhibition reaction were similar to A/Texas/1/77, and the majority of H1N1 isolates were similar to A/USSR/90/77. Antigenic analysis of isolates, however, identified a small number of variants of H3N2 and H1N1 strains.

Adolescent↗
PubMed1979

Minimum vascular occlusive force.

A mathematical analysis of the minimum occlusion force necessary to occlude small vessels based on the parametric influence of blood pressure, vessel diameter, clamp width, and vessel shape after clamping was performed. The results were confirmed by in vivo experimentation with 60 rat aortas (of 1.8 to 2.4 mm caliber) using a variable-force clamp gauge developed in our laboratory. Experimental and theoretical results differed by only 3 gm. Scanning electron microscopy revealed that the initial changes in the endothelium occurred in smaller radii of curvature. Increased pressure resulted in gross morphological changes across the vessel. The minimum occlusion force (as determined by the variable-force clamp gauge) produced only minimal endothelial damage.

Animals↗
PubMed1977

Epinephrine-induced cystoid macular edema in aphakic eyes.

A population of glaucomatous aphakic eyes being treated with topical epinephrine compounds was studied in order to determine the incidence of cystoid macular edema that had been induced by this medication. Eyes were considered responders only if fluorescein angiography demonstrated that macular edema was eliminated with discontinuation of epinephrine and recurred with reapplication of epinephrine. Reversible maculopathy occurred in six of 47 eyes. Topical epinephrine caused macular edema in an appreciable percentage of aphakic eyes, and we recommend that other medications be used to control glaucoma in aphakic patients when possible. If epinephrine compounds are required, periodic angiography is advisable.

Cataract Extraction↗
PubMed1977

Free-living volunteer's motivations and attitudes toward pharmacologic studies in man.

Two groups of volunteers who had participated in pharmacologic studies were interviewed about their impressions of such studies. One group was from a university community, the other from the pharmaceutical industry. The differences between the two groups were correlated with their respective backgrounds. Both groups had favorable impressions about drug studies and investigators. Most were satisfied with the information given them about the nature and risks of the studies, but some believed that a written description of the study that they could consult at home would improve their understanding of the information. Financial reward was the primary reason given by both groups for volunteering, but the perceived risk of the study was the ultimate deciding factor. The volunteers disliked having their mobility restricted and for this reason might not be willing to participate in long-term studies, such as those formerly carried out in prisons. Alternative sources of volunteers for long-term studies will have to be found.

Adult↗