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Biomedical subjects

A Anthony

Publications and source records attributed to A Anthony.

At least 109 records · Page 6Linked to original sources
PubMed1983

Quantitative cytochemical analyses of ovarian luteal and interstitial cell RNA in relation to plasma progestins during pseudopregnancy in the rat.

Luteal and interstitial cell RNA contents and circulating progesterone (P) and 20 alpha-hydroxypregn-4-ene-3-one (20 alpha-OH P) levels were measured during pseudopregnancy in order to characterize relationships between ovarian 20 alpha-OH P secretion and luteal regression. Functional luteolysis, as manifested in depressed P levels, was not associated with concurrent elevations in 20 alpha-OH P. Rather, augmented 20 alpha-OH P levels were evidenced in periovulatory periods at the onset and termination of pseudopregnancy, subsequent to RNA accumulation in both luteal and interstitial compartments. It is postulated that 20 alpha-OH P, the putative inactive metabolite of P, is produced by both ovarian compartments in a cyclic manner and in response to gonadotrophin released in the preovulatory period.

20-alpha-Dihydroprogesterone↗
PubMed1983

Brain neuronal RNA metabolism during acute soman toxication: effects of antidotal pretreatments.

Effects of various antidotal treatments on neuronal RNA contents and on soman induced RNA and acetylcholinesterase (AChE) depletion were monitored using quantitative cytochemical techniques. In rats only with antidotes, atropine depressed whereas pralidoxime (2-PAM) elevated RNA contents of both caudate and cerebrocortical (Layer V) neurons. Soman produced a virtually complete inhibition of AChE activity and a moderate decline in neuronal RNA contents. Atropine pretreatment partially restored neuronal RNA levels. Atropine + 2-PAM prophylaxis eventuated in a complete restoration of RNA levels but no reactivation of AChE. Addition of physostigmine to the atropine + 2-PAM treatment regimen resulted in appreciable AChE reactivation but reduced RNA levels. The overall data indicate that: (1) soman-induced neuronal RNA depletion can be completely reversed by antidotal pretreatments; (2) no precise relationship exists between the extents of antidote-induced restoration of RNA and AChE levels; and (3) 2-PAM exerts marked effects on the brain neuronal network which are unrelated to AChE reactivation. It is postulated that effects of soman and antidotes on neuronal RNA metabolism may signify alterations in acetylcholine (ACh) sensitivity and that pharmacologic manipulation of ACh responsiveness during organophosphate cholinesterase poisoning may be a mechanism for additional therapeutic intervention.

Acetylcholinesterase↗
PubMed1982

Effects of environmental enrichment on old mice.

Fifteen male C57BL/6J mice, exposed to an enriched environment from age 600 to 750 days, were compared with 15 matched controls on 4 learning problems and an activity test. The enriched mice were significantly superior on an incidental learning and a food-seeking task, but did not differ significantly from controls on a brightness discrimination task, the Lashley III maze and an activity test. The relative abundance of high and low ribonucleic acid-containing cerebrocortical cells differed significantly between groups; the enriched mice had more cells with very high levels of RNA. The mammalian brain appears to remain responsive to environmental enrichment well into advanced age.

Age Factors↗
PubMed1981

Hydrocortisone effects on nucleic acid and nuclear protein content and protein metabolism in aging WI-38 cells.

Confluent late passage WI-38 human diploid fibroblast cultures grown in the presence or absence of hydrocortisone for fifteen population doublings were measured cytochemically for DNA, nuclear RNA, basic nuclear protein and acidic nuclear protein content during a 12-hour interval following a medium-change stimulation. Radioisotope tracer studies were utilized to assess the effects of prolonged hydrocortisone treatment on protein synthesis and degradation in aging confluent and logarithmically growing cultures. Hydrocortisone-treated cultures exhibited an increased Feulgen--DNA stainability, no difference in basic nuclear protein content, a significantly larger initial decrease followed by an increase in acidic nuclear protein content, and elevated levels of nuclear RNA as compared to untreated controls. Hydrocortisone treatment also resulted in increased incorporation of leucine into protein and decreased breakdown of pre-labeled protein in both confluent and logarithmically growing cultures. These results indicate that many of the metabolic changes associated with proliferation are stimulated by prolonged hydrocortisone treatment of late passage WI-38 fibroblast cells.

Cell Division↗
PubMed1981

Age-related changes in brain RNA of noise stressed mice.

Correlative data were obtained on RNA levels of cerebrocortical neurons, adrenal fasciculate cell RNA content and serum corticosterone levels in 10, 40 and 100 week old male C57BL/6J mice immediately following a 30 interval of continuous noise stimulation (100 dB re 2 x 10(-5) N/m2, 0.35-20 kHz) and at 1 hr and 4 hr recovery intervals. Quantification of cellular RNA levels entailed use of scanning-integrating microdensitometry of azure B stained tissue sections. Hormonal analyses were done by radioimmunoassay. Noise stimulation induced a mild to moderate adrenocortical activation and a moderate elevation of serum corticosterone levels in all age groups. Noise exposure also resulted in an increase in the RNA content of cerebrocortical neurons. However, maximal neuronal RNA levels proved to be considerably lower (32-36%) in 100 week old mice as compared to both 10 and 40 week old mice during the post-exposure intervals. The overall data support the existence of a lower neuronal capacity for sensory induced RNA synthesis in 100 week old mice. The data also suggest that age dependent differences in neuronal responsiveness are not directly related to the extent of adrenal RNA activation or to a lower availability of circulating glucocorticoids.

Adrenal Cortex↗
PubMed1981

Feulgen-deoxyribonucleic acid analysis of rabbit aortic smooth muscle cells using scanning- integrating microdensitometry.

A procedure entailing the use of the Feulgen reaction is described for precise quantification of nuclear DNA levels in smooth muscle cells (SMC) of paraffin-processed microtome sections of the rabbit aorta. It was established that maximal, stable, and reproducible Feulgen-DNA (F-DNA) staining of SMC nuclei is achieved using 3.5 N HCl hydrolysis of 30-50 min prior to staining of aortic sections in Schiff reagent for 60 min at 22 degrees C. Scanning-integrating microdensitometry of Feulgen-stained SMC revealed that the tunica media is comprised of a relatively homogeneous population of cells with between 0.3 and 1% of the SMC nuclei yielding 3C or 4C (tetraploid) F-DNA levels, depending on location within the aortic wall. The nuclear chromatin in inner medial SMC was found to be in a more dispersed state than that of outer SMC (using nuclear area and nuclear susceptibility to acid hydrolysis as indices of chromatin dispersion). A linear correspondence was evidenced between nuclear area and nuclear F-DNA stainability throughout the tunica media. The observation that the lumenal portion of the tunica media contains a greater abundance of SMC with large, vesicular nuclei is interpreted as reflecting a greater metabolic reactivity of this compartment relative to that of SMC bordering the tunica adventitia.

Animals↗
PubMed1979

Cytochemical bioassay and radioimmunoassay of ACTH in noise stressed rats.

Serum corticosterone and ACTH levels were measured in rats subjected to one and two 30 min intervals of noise (100 dB, 250--20,000 Hz). Both hormones were elevated immediately after noise exposure, dropped below pre-exposure levels after a 2 hr recovery interval and were again elevated with a second exposure. The ratio of immunoactive to bioactive ACTH was slightly depressed after one exposure and markedly depressed after two successive noise exposures (relative to controls) indicating that multiple exposure to auditory stimulation effects a proportionally greater output of bioactive ACTH.

Acoustic Stimulation↗
PubMed1978

Cytophotometric analyses of myocardial RNA in rats exposed to altitude hypoxia.

Analytical cytophotometry of azure B-stained heart sections was employed to investigate the pattern of myocardial ribonucleic acid (RNA) alterations in rats exposed to acute (1-2 days) and prolonged periods (1-8 weeks) of hypoxia exposure (380 torr). Data support the existence of a slight transient drop in myocardial RNA on day one of exposure followed by a restoration to levels slightly elevated over controls during a 1- to 8-week exposure interval. Because of the high variability in RNA levels among myocytes (coefficient of variation, ca 40%), a shift in the proportion of low and high RNA containing segments of the myocyte population proved to be a more sensitive indicator of suppression or augmentation of RNA synthesis than the use of average RNA levels of the cell population analyzed. Microscopic analyses revealed the presence of compensatory vascular responses which could be effective in ameliorating the extent of tissue hypoxemia, i.e., capillary vasodilation on day 1 with a progressive increase in vascularization with prolonged exposure.

Altitude↗
PubMed1977

Myocardial Feulgen-DNA levels and capillary vascularization in hypoxia-exposed rats.

Male abino rats were exposed to simulated altitude of 18,000 ft (380 Torr) for 1 day to 8 wk. Histological sections of heart ventricles were stained by the Feulgen technique and amounts of Feulgen-DNA were determined cytophotometrically. Heart weights, relative to body weights, increased over controls at all exposure periods, as did myocardial capillary vascularization. Ninety percent of cardiac muscle nuclei were found to contain tetraploid amounts of DNA. All nuclei exhibited a high degree of chromatin dispersion in exposed and unexposed rats, which reflects a highly reactive metabolic state of cardiac cells in both groups. There was no evidence of increased ploidy or increased DNA synthesis associated with hypertrophy after acute or chronic hypoxia exposure. The data suggest that an initial event which could facilitate augmented protein synthesis during hypoxia acclimation appears to be an increased availability of oxygen and/or nutrients brought about by an expansion of the capillary bed and vascular proliferation.

Animals↗
PubMed1977

Scanning Feulgen-deoxyribonucleic acid cytophotometry of Papanicolaou destained preparations.

Feulgen deoxyribonucleic acid cytophotometry of Papanicolaou destained specimens revealed a differential loss in Feulgen reactivity among human buccal and cervical smears, cultured embryonic lung fibroblasts and invasive cervical carcinoma cells. Loss in Feulgen reactivity in Papanicolaou destained fibroblasts and polyploid nuclei of malignant lesions was observed to result in underestimates of relative Feulgen deoxyribonucleic acid and nuclear area values using scanning integrating microdensitometry. Thus, Papanicolaou stained preparations may not be suitable for deoxyribonucleic acid quantification of high ploidy lesions since distributional absorption error is unpredictably influenced by such factors as ploidy level, nuclear size, chromatin dispersion and differential aldehyde loss during destaining. Feulgen deoxyribonucleic acid cytophotometry of Papanicolaou stained preparations can be useful for differentiating benign from malignant lesions if extent of aneuploidy (as reflected in abnormal deoxyribonucleic acid frequency distribution profile) is used as a diagnostic indicator.

Cell Nucleus↗