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Biomedical subjects

R E Anderson

Publications and source records attributed to R E Anderson.

At least 361 records · Page 20Linked to original sources
PubMed1982

The manpower situation in pathology: implications for the future.

With the exception of academic pathology and specific subspecialty areas, manpower in pathology is currently in a state of apparent equilibrium between supply and demand. Exogenous influences, and especially an influx of Americans who have attended foreign-chartered medical schools, could disturb this apparent equilibrium. Other key manpower issues with respect to pathology include mechanisms to determine optimal numbers of pathologists, the future productivity of pathologists, current and prospective needs in academic pathology and subspecialty areas, and the role of the federal government in the area of medical manpower. Recommendations to deal with these and related issues are presented.

Foreign Medical Graduates↗
PubMed1982

Cerebral blood flow, brain pH, and oxidative metabolism in the cat during severe insulin-induced hypoglycemia.

The effects of severe hypoglycemia on brain pH, cerebral blood flow (CBF), and other physiologic and metabolic parameters were studied in 26 cats subjected to insulin hypoglycemia. Two groups were utilized to compare the effects of anesthesia. The halothane group was composed of 14 animals and the barbiturate group contained 12 animals. Insulin was administered by both the intravenous and intramuscular routes until there was a severe electroencephalographic (EEG) change or until 6 h had elapsed. The cerebral responses to hypoglycemia demonstrated the following: CBF was unaffected by severe hypoglycemia in normotensive animals with or without EEG changes; brain pH was essentially constant in all groups regardless of glucose levels, CBF, or EEG; and the EEG abnormalities corresponded closely to brain glucose levels. Cerebral adenosine triphosphate and phosphocreatine levels were lowest in the animals with isoelectric EEGs. We conclude that CBF and brain pH in the normotensive cat under general anesthesia are relatively unaffected by insulin hypoglycemia despite the presence of severe EEG changes and diminished cerebral energy reserves. The study suggests tha the PaCO2-CBF response curve is ot dependent upon the metabolic integrity of cerebral tissue and is mediated by pathways separate from those of autoregulation.

Animals↗
PubMed1982

Third report of the ASCP/CAP/APC joint task force on pathology manpower.

This report concerns the results of pathology manpower surveys encompassing responses from four groups of pathologists: (1) solo and group practitioners; (2) training program directors; (3) house staff; (4) diplomates seeking positions. The rate of response by all four groups is judged highly satisfactory. The results show an approximate balance between supply and demand with respect to manpower in pathology. Comparison with the results of two similar surveys conducted by the Joint Task Force shows the following trends: (1) a continued marked reduction of foreign medical graduate (FMG) trainees; (2) continued increase in the proportion of women entering pathology; (3) an increase in the size of the average practice and a corresponding decrease in the proportion of pathologists in solo practice; (4) a decreased tendency of practicing pathologists to relocate; (5) an increase in pathologists lost to the profession because of death, disability and retirement; (6) a slight decrease (approximately 50) in the number of funded full-time positions and a slight increase in the number of part-time vacancies.

Aged↗
PubMed1982

Application of a three-dimensional display in diagnostic imaging.

An autostereoscopic viewing device for tomographic scans that allows a physician to examine multiple computed tomography sections with each section properly positioned in three dimensions has been constructed and tested. Images produced on the device allow the observer to utilize both motion parallax and stereoscopic depth cues as if viewing a real three-dimensional (3D) object. These 3D images can be very striking because of the ease with which one can form a true impression of depth relationships. We describe operating principles of the viewing device and the appearance of images produced on it. Stereo photographs made from 3D images displayed on the device are included to illustrate potential applications and problems.

Data Display↗
PubMed1982

Carbonic anhydrase localization by light and electron microscopy: a comparison of methods.

The histochemical localization of carbonic anhydrase by Hansson's cobalt-salt method was compared with immunocytochemical localization in the proventriculus (glandular stomach), the chorioallantoic membrane, and in articular and growth-plate cartilages from the domestic hen. Numerous differences were observed. Staining was positive by Hansson's method and negative by immunocytochemistry for the submucosal glands of the proventriculus, articular cartilage cells, resting and proliferating cells of the growth plate, nuclei, and intercellular spaces. Red blood cells stained faintly and inconsistently by Hansson's method. Both methods were in agreement for the cytoplasm of the surface mucosal cells of the proventriculus, the cytoplasm of the villus cavity cells in the chorioallantoic membrane, and in hypertrophic cells of growth-plate cartilage. Acetazolamide usually inhibited the histochemical reaction, even in those sites that, according to other methods, did not contain enzyme. Consequently, acetazolamide inhibition appears to be an unreliable control for the histochemical reaction.

Animals↗
PubMed1982

Identification of carbonic anhydrase in chick growth-plate cartilage.

Carbonic anhydrase has been localized by immunocytochemistry in the cells and territorial matrix of the hypertrophic and calcifying zones of chick growth-plate cartilage. Adjacent epiphyseal and articular cartilage were not stained. By biochemical assay the activity levels were 61.3, 1.8, 34.7, and 703.3 units/g wet weight for growth plate, epiphyseal/articular cartilage, spongiosa, and blood, respectively. The role of the enzyme in growth plate is discussed.

Animals↗
PubMed1982

Computer-assisted morphometric analysis of radiation injury in murine lymphocytes.

Groups of mice were killed 1, 3, 7 and 15 days after whole body exposure to 0, 5, 50 or 500 rads of irradiation. Lymphocytes were harvested from the peripheral blood and spleen for total and differential leukocyte counts, for determination of the absolute numbers of thymic-dependent (T) and bone marrow-dependent (B) cells and the in vitro responsiveness to phytohemagglutinin (PHA), concanavalin A (Con A) and lipopolysaccharide (LPS) mitogens and for computer-assisted morphometric analysis (CAMA) of Feulgen-stained nuclei. Alterations in functional activity and morphometric composition showed the same trends with respect to radiation injury, with maximum effects observed three days after exposure. The spleen contained a greater proportion of altered cells than did the peripheral blood. Comparison of the results with similar data obtained from lymphocytes irradiated in vitro showed that the same micromorphometric descriptors serve to distinguish irradiated from control cells in both cases.

Animals↗
PubMed1982

Membrane addition to rod photoreceptor outer segments: light stimulates membrane assembly in the absence of increased membrane biosynthesis.

The effect of light on the biosynthesis and the assembly of rod photoreceptor outer segment membranes was analyzed in vitro using retinas from Xenopus laevis. The number of open discs at the base of the outer segment was used as a morphologic index to evaluate relative differences in rates of membrane assembly. Assembly was stimulated in vitro by light, as evidenced by a greater number of open discs that accumulated in light-exposed retinas than that in retinas maintained under the same conditions but in darkness. Quantitative autoradiography indicated, however, that unlike membrane assembly, the incorporation of 3H-leucine or 3H-mannose into proteins by rods was nearly identical in light-stimulated and dark-maintained retinas. Likewise, the synthesis of opsin, a protein destined for the rod outer segment, was not affected by light. We conclude from these studies that the enhanced rate of outer segment membrane assembly that occurs during the early light phase of the diurnal cycle takes place in the absence of an increase in the rate of biosynthesis of opsin, the major outer segment membrane protein.

Animals↗
PubMed1982

The pathogenesis of radiation injury in complex tissues: an overview of problems and probes.

The evaluation of radiation injury in complex organs has tended to lag behind comparable areas of investigative interest. This observation is somewhat surprising in view of the increased use of radiotherapy as a primary or adjuvant mode of therapy for malignant disease. In part, this problem appears to relate to the difficulty of identifying and quantifying the morphologic consequences of radiation injury in complex organs, in which the various component tissues exhibit a broad spectrum of radiosensitivities. Two approaches have been employed to address this problem: (1) utilization of sophisticated probes to evaluate the functional and morphologic sequelae of radiation injury and (2) segmentation of complex tissues into their component parts, which are then evaluated individually. Both approaches are illustrated in the papers presented in this issue. The purpose of this overview is to call attention to some of the attendant difficulties of the former approach, as seen in an ongoing investigative program concerned with radiation injury of the kidney.

Animals↗
PubMed1982

Retinal protein synthesis in relationship to environmental lighting.

A series of in vivo and in vitro experiments using Xenopus laevis juvenile toads was conducted to probe the relationship between environmental lighting and protein synthesis in the retina. Autoradiographic and biochemical analyses indicated that measurable changes in protein synthesis did not occur during a normal diurnal cycle when animals were conditioned to 12 hr light followed by 12 hr darkness each day (LD). However, when retinas from animals maintained in continuous darkness (DD) for 3 days were incubated with 3H-leucine, there was a 40% reduction in the specific radioactivity of total retinal proteins compared with retinas from animals maintained in continuous light (LL) for 3 days or on the LD cycle. Retinas from DD animals injected with 3H-leucine showed a 48% reduction in protein synthesis compared with retinas of LL animals. In autoradiographs of retinas from in vivo or in vitro experiments, grain counts were 40% lower in the total retinas of the DD animals compared with retinas of LL animals. This reduction occurred throughout the entire retina and was not restricted to any specific cell type. There was also a 35% reduction in the rate of radioactive band displacement in the rod outer segments of DD animals, although the percent of 3H-leucine incorporated into opsin relative to total retinal protein was the same for both groups. We conclude from these studies that fluctuations in the rate of protein synthesis during the normal light-dark cycle are not detectable. However, major differences in protein synthesis are evident when animals are stressed with continuous darkness for several days. This effect is not restricted to any particular retinal layer but occurs throughout the entire retina. Moreover, prolonged darkness affects protein synthesis in extraocular tissues as well.U

Animals↗
PubMed1982

Effects of irradiation upon the response of murine spleen cells to mitogens.

The mitogenic response of murine spleen cells exposed to graded doses of radiation was evaluated. Low-dose exposures were associated with an augmented response to concanavalin A (Con A) that was most marked with 100 rads. Low-dose augmentation of phytohemagglutinin (PHA) stimulation was equivocal and most pronounced in cells exposed to 10-20 rads. Augmentation was only demonstrable when the cells were irradiated immediately prior to mitogenic stimulation. Timed exposures after stimulation with Con A or PHA showed no evidence that mitogen activation increased radioresistance, although the possibility could not be excluded that activation protects against interphase cell death. Reduced isotope incorporation was associated with all doses of radiation evaluated in cells stimulated with lipopolysaccharide (LPS) or pokeweed mitogen (PWM). On this basis it is concluded that 1) each of the mitogens tested differs in its capacity to stimulate irradiated spleen cells; 2) radiation-induced augmentation is noted with those mitogens (Con A and possibly PHA) known to activate only T cells; 3) radiation-induced augmentation may be due to the release of mitogenically active molecules by injured lymphocytes.

Animals↗
PubMed1982

Radiation-induced augmentation of the response of A/J mice to SaI tumor cells.

Whole-body exposure of A/J mice to low doses (5-25 rads) of ionizing radiation immediately prior to the inoculation of 10(4) Sarcoma I (SaI) cells results in smaller tumors than are observed in sham-irradiated control animals. The irradiated group also contains a greater proportion of mice that fail to develop tumors or that demonstrate tumor regression. Low-dose augmentation is 1) less pronounced in recipients that have undergone splenectomy; 2) not evident in adult thymectomized-lethally irradiated-bone-marrow-restored (ATxXBM) animals, where the opposite effect is seen (eg, low-dose enhancement of tumor growth); and 3) abolished by the administration of normal syngeneic spleen cells unless the latter have been depleted of T cells. On this basis, a very radiosensitive T cell with suppressor activity is implicated in this phenomenon. Low-dose exposure at various times prior to tumor inoculation suggests that this cell regenerates in 5-10 days after irradiation.

Animals↗
PubMed1982

Protective effect of lidocaine during regional myocardial ischemia: an altered pathophysiologic response assessed by NADH fluorescence.

Studies were undertaken to determine the effects of lidocaine on ischemic myocardium, which was induced by coronary artery constriction in open-chested dogs. A real-time epicardial fluorescent technique to detect in vivo-reduced nicotinamide adenine dinucleotide (NADH) during 60 seconds of ischemia was used. Blood flow of ischemic myocardium was measured by using radioactive microspheres of 9 +/- 1 micrometers (mean +/- SE) and was compared with that of normal myocardium, shown by injection of alpha-zurine blue dye. Lidocaine effectively reduced peak NADH fluorescence by 18.6%, from 93.9 +/- 7.2 to 76.4 +/-4.1 mV (p less than 0.005). Lidocaine delayed the onset of fluorescence (2.2 +/- 0.2 versus 1.3 +/- 0.1 s p less than 0.002) and facilitated the recovery from ischemia (38.4 +/- 2.9 versus 54.8 +/- 2.9 s p less than 0.001). Increase in NADH concentration during ischemia correlated (r=0.76, p less than 0.006) with ischemic fluorescence. These findings were independent of altered hemodynamics or change in myocardial blood flow. Results indicate that lidocaine provides myocardial cellular protection during transient ischemia; there is an altered NADH fluorescent response to coronary artery occlusion.

Animals↗