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Biomedical subjects

R E Anderson

Publications and source records attributed to R E Anderson.

At least 181 records · Page 10Linked to original sources
PubMed1991

Fatty acid and molecular species compositions of phospholipids and diacylglycerols from rat retinal membranes.

The relative proportions and compositions of the diacyl molecular species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidic acid (PA), and diacylglycerol (DG) from rat retinal membranes were determined. Two membrane fractions were derived by discontinuous sucrose gradient floatation: rod outer segment (ROS) and 'rest of the retina' (ROR). ROR is defined as those membranes pelleted as 100,000 g following removal of the ROS. Diacylglycerols were prepared from PC, PE and PS by phospholipase C treatment and were converted into the corresponding 1,2-diacylglycerobenzoates (DGBZ). PI, PA, and DG were converted into 1,2-diacylglyceroacetates (DGAC) by acetolysis. The molecular species of the DGBZ and DGAC were resolved by reverse-phase HPLC and detected by UV absorption at 230 and 210 nm, respectively. Fatty acid methyl esters of PC, PE, PS, PI and DG from ROS and ROR were prepared and analysed by GLC. The fatty acid and molecular species patterns of PC, PE and PS were similar in both membrane fractions, although the levels of docosahexaenoic acid (22:6 omega 3) and 22:6-containing molecular species were lower in ROR than in ROS, PE and PS were enriched in 22:6 omega 3 and 18:0, an evidenced by the high levels of 18:0-22:6 and 22:6-22:6 molecular species. PC contained relatively more saturated and monoene species, such as 16:0-16:0, 16:0-18:0, 16:0-18:0, 16:0-18:1 and 18:0-18:1. The fatty acids and molecular species patterns of DG, PI and PA in ROS and ROR differed from those of PC, PE and PS.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Metabolism of lipid molecular species in rat rod outer segments.

We have studied the metabolism of selected diacyl molecular species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and diacylglycerol (DG) from rat rod outer segments (ROS). Rats were injected intravitreally with [2-3H]glycerol. At 1, 2, 3, 4 and 6 days post-injection, ROS phospholipids and DG were isolated by two-dimensional thin-layer chromatography (TLC), derivatized, and fractionated into molecular species by high-performance liquid chromatography (HPLC). Selected molecular species were quantitated and counted for radioactivity. We found the following. In PC and PE, the specific activities of 22:6-22:6, 18:1-22:6 and 16:0-22:6 were highest at day 1 and then decreased in a nearly exponential manner. In contrast, the specific activities of 18:0-22:6 and 18:0-20:4 were substantially lower than these three molecular species and changed little over the 6-day period. In PS, the specific activities of 22:6-22:6, 18:0-22:6 and 18:1-22:6 were similar and did not reach their maximum until the 3rd or 4th days. In PC, the specific activities of the five molecular species examined were two to three times higher at day 1 than the same species in PE and PS. In PI and DG, the major molecular species were 16:0-20:4 and 18:0-20:4. The specific activities of these two molecular species at day 1 were about ten times higher than those of 20:4-containing species in PE and PC, and showed the most rapid turnover of any of the molecular species examined in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Alteration of gastric surface cell pH regulation by sodium taurocholate.

Gastric mucosal cells from guinea pigs were grown in cell culture. Acridine orange fluorescence at 624 nm was used as an qualitative indicator of intracellular pH. The cultured cells were exposed to Hank's solution at pH 7.4, 6.0, 5.0, 4.0, 3.0, and 1.8 for 30 min. After removal of the acid, the cells were loaded with acridine orange for qualitative pH assessment. The cells developed alkaline shifts in the cytoplasmic pH in direct proportion to the acid load. This alkaline overcorrection after exposure to acid was blocked by amiloride and blunted by taurocholic acid in a dose-dependent fashion. These results suggest that gastric surface cells may regulate their cytoplasmic pH with a sodium-hydrogen antiporter. These results also suggest that this antiport system may be adversely affected by bile salts.

Acid-Base Equilibrium↗
PubMed1991

Academic manpower survey of 1990: II. Kinetics in the United States (from the Joint Task Force on Pathology Manpower ASCP/CAP/APC).

Survey data obtained from chairmen of United States departments of pathology shows a continued shortage of faculty, especially those with the MD or MD/PhD degree. Losses of such faculty by responding departments during the 12 months prior to the survey were distributed as follows: retirement, 40 (15.6% of total); disability/death, 19 (7.4%); termination, 23 (8.9%); resignation, 172 (69.3%); and other, 3 (1.2%). Resignations were due primarily to decisions to join another university (41.4%) or to enter private practice (42.5%); a small proportion were due to individuals who left academe for a pathology position in government or industry, or left both academe and pathology for another field. Comparison with a similar survey performed in 1984 suggests that the manpower situation in academic pathology is worsening, especially with respect to physician faculty. An assessment of those factors known to influence manpower kinetics suggests that it will continue to deteriorate for the foreseeable future with an adverse impact on all sectors of pathology.

Education, Medical↗
PubMed1991

Academic manpower survey of 1990: I. Descriptors of departments of pathology in the United States (from the Joint Task Force on Pathology Manpower ASCP/CAP/APC).

A survey of chairmen of United States departments of pathology (97% response rate) augmented with data from the Association of American Medical Colleges shows that roughly two thirds (65%) of departmental faculty are physicians, the great majority of whom are pathologists. Most of the remainder are persons with solely the PhD degree (26.4% of faculty). The composition of departments of pathology in terms of age, gender, ethnic origin, academic rank, and tenure status is also reported. In contrast to a comparable survey performed 5 years previously, the present report shows that in 1989, departments of pathology contained (1) 20.6% more faculty positions, (2) a greater proportion of faculty members with a PhD degree, (3) greater numbers of open positions, and (4) a probable increase in the proportion of faculty that are female and that are of an ethnic minority.

Faculty, Medical↗
PubMed1991

The uses and value of autopsy in medical education as seen by pathology educators.

A national meeting of pathology educators in 1989 provided the impetus for an exploration of new uses of autopsy in medical education. A month before the conference, the authors sent a questionnaire about the uses and value of autopsy in medical education to 120 persons registered to attend the conference. They used the 98 responses, representing 69 U.S. and Canadian medical schools, as the basis of a workshop on the place of autopsy in future medical education. The present article is a report of the authors' findings from the questionnaire and workshop. They found that the uses of autopsy go far beyond the traditional uses in teaching clinical pathophysiology, clinico-pathologic correlations, clinical anatomy, gross and microscopic anatomy of disease, and visual skills. Emphasis was placed on the potential role of autopsy in education regarding legal/judicial proceedings, vital statistics, epidemiologic investigations, and public health, and in the understanding of such complex matters as medical fallibility, medical uncertainty, and grief. These purposes were seen as congruent with current societal concerns about the need to reverse the trend toward dehumanization of medicine and physicians. The inability to realize these aims in the face of a precipitous drop in the autopsy rate is discussed.

Autopsy↗
PubMed1991

CD8+ T lymphocytes and progression to AIDS in HIV-infected men: some observations.

The relationship between CD8+ lymphocyte counts and progression to AIDS was studied in 340 HIV-1-seropositive men participating in a population-based prospective study. Overall, the relative hazard for developing AIDS during 60 months of observation was slightly elevated (1.08, P = 0.003), indicating an 8% increase in risk of progression for every 100 CD8+ cell count increment. When the data were analyzed in relation to date of diagnosis, the relative hazard was depressed (0.90, P less than 0.001) for the period 6 months prior to diagnosis, but was close to 1.0 for the period 6-36 months prior to diagnosis. These findings suggest a complex relationship between CD8+ cell counts and progression to AIDS, with the possibility that various subsets of the CD8+ compartment play different roles.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Conservation of docosahexaenoic acid in rod outer segments of rat retina during n-3 and n-6 fatty acid deficiency.

We investigated the mechanism by which rat retina conserves docosahexaenoic acid during essential fatty acid deficiency. Weanling female albino rats were fed diets containing either 10% by weight hydrogenated coconut oil, safflower oil, or linseed oil for 15 weeks. Plasma and rod outer segment (ROS) membranes were prepared for fatty acid and phospholipid molecular species analysis. In addition, retinas were removed for morphometric analysis. We found the following: (1) Plasma phospholipids and cholesterol esters from coconut oil, safflower oil, and linseed oil diet groups were enriched in 20:3(n-9), 20:4(n-6), and 20:5(n-3), respectively. The levels of these 20-carbon fatty acids in the ROS, however, were only slightly affected by diet. (2) The fatty acids and molecular species of ROS phospholipids from the safflower oil and coconut oil groups showed a selective replacement of 22:6(n-3) with 22:5(n-6), as evidenced by a reduction of the 22:6(n-3)-22:6(n-3) molecular species and an increase in the 22:5(n-6)-22:6(n-3) species. (3) The renewal rate of ROS integral proteins, determined by autoradiography, was 10% per day for each diet group. (4) Morphometric analysis of retinas showed no differences in the outer nuclear layer area or in ROS length between the three groups. We conclude that the conservation of 22:6(n-3) in ROS is not accomplished through reductions in the rate of membrane turnover, the total amount of ROS membranes, or in the number of rod cells. The retina may conserve 22:6(n-3) through recycling within the retina or between the retina and the pigment epithelium, or through the selective uptake of 22-carbon polyunsaturated fatty acids from the circulation.

Animals↗
PubMed1991

Identification and immunolocalization of phospholipase C in bovine rod outer segments.

Bovine rod outer segments (ROS) contain a phospholipase C (PLC) that hydrolyzes phosphatidylinositol 4,5-bisphosphate. Approximately 60-70% of PLC activity is recovered in soluble extracts of ROS. Moreover, the specific activity of this soluble PLC is approximately 10-fold higher than that of resealed ROS enzyme activity. Peptide-specific antiserum (Ab 1109) directed against a highly conserved sequence of the Y-region found in several PLC isozymes was used to detect any PLC belonging to this family. This antibody specifically recognized a protein of apparent molecular mass of approximately 140 kDa present in immunoblots of soluble extracts of both ROS and whole retina. The elution profile of this 140-kDa antigen from a Sephadex G-150 column coincided with the peak of PLC activity, suggesting PLC activity is associated with the 140-kDa protein. Immunocytochemical studies of bovine retina using Ab 1109 showed pronounced immunoreactive labeling in the photoreceptor layer. In resealed ROS and washed ROS membranes, Ab 1109 recognized an additional protein of apparent molecular mass of 70 kDa not usually detectable in soluble extracts of ROS, suggesting the presence of at least two isozymes of PLC in ROS.

Animals↗
PubMed1991

Laparoscopic cholecystectomy is less expensive than open cholecystectomy.

Laparoscopic cholecystectomy (LC) is emerging as the most attractive alternative to open cholecystectomy (OC) ever offered to patients. It combines a rapid recovery time with definitive therapy for their affliction. In addition to its greater acceptance by patients, LC has the potential to be more economical than OC because of the markedly shorter hospital stay required by most patients who have undergone LC. In this article we compare the hospital charges for patients undergoing LC with a matched group of patients undergoing OC. The hospital charge was $4,070 +/- 297 (mean +/- SEM) for patients undergoing LC and $5,017 +/- 497 for patients undergoing OC. This difference arises from the mean cost of in-patient care, which was $353 +/- 40 for LC patients and $1,335 +/- 138 for OC patients. LC appeared to be a bargain, both economically and physiologically.

Adult↗
PubMed1991

The initial immune response to HIV and immune system activation determine the outcome of HIV disease.

A study was conducted to assess the relative contribution of the HIV-1-specific immune response and -nonspecific immune activation to HIV disease progression. The titer of antibody to the p24 core protein and the concentration of serum neopterin were measured in 238 HIV-1-seropositive subjects in a prospective cohort study of homosexual men. Antibody titers were extremely variable among cohort participants but relatively stable over time, suggesting inherent differences in the initial immune response capacity. Neopterin concentrations were also variable at cohort entry but generally increased over time. These two markers, measured at cohort entry, had powerful and independent predictive value for the development of AIDS up to 54 months before diagnosis. Subjects with low antibody titers and high levels of neopterin, had the highest incidence of AIDS (60% over 54 months). Patients with low antibody or high neopterin alone had an intermediate risk (34% incidence) and less than 10% of those with high antibody and low neopterin developed AIDS. We propose that the initial immune response to HIV and virus-mediated immune system activation are independent and innately variable components of an individual's response to HIV infection that interact to determine the clinical outcome.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Recycling of docosahexaenoic acid in rat retinas during n-3 fatty acid deficiency.

About 50% of the fatty acids in retinal rod outer segments is docosahexaenoic acid [22:6(n-3)], a member of the linolenic acid [18:3(n-3)] family of essential fatty acids. Dietary deprivation of n-3 fatty acids leads to only modest changes in 22:6(n-3) levels in the retina. We investigated the mechanism(s) by which the retina conserves 22:6(n-3) during n-3 fatty acid deficiency. Weanling rats were fed diets containing 10% (wt/wt) hydrogenated coconut oil (no n-3 or n-6 fatty acids), linseed oil (high n-3, low n-6), or safflower oil (high n-6, less than 0.1% n-3) for 15 weeks. The turnover of phospholipid molecular species and the turnover and recycling of 22:6(n-3) in phospholipids of the rod outer segment membranes were examined after the intravitreal injection of [2-3H]glycerol and [4,5-3H]22:6(n-3), respectively. Animals were killed on selected days, and rod outer segment membranes, liver, and plasma were taken for lipid analyses. The half-lives (days) of individual phospholipid molecular species and total phospholipid 22:6(n-3) were calculated from the slopes of the regression lines of log specific activity versus time. There were no differences in the turnover rates of phospholipid molecular species among the three dietary groups, as determined by the disappearance of labeled glycerol. Thus, 22:6(n-3) is not conserved through a reduction in phospholipid turnover in rod outer segments. However, the half-life of [4,5-3H]22:6(n-3) in the linseed oil group (19 days) was significantly less than in the coconut oil (54 days) and safflower oil (not measurable) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Comparison of faculty members' and students' perceptions concerning performance criteria and evaluation strategies at the University of New Mexico School of Medicine.

Faculty members' and students' perceptions concerning the relative importances of (1) various performance criteria for students and (2) strategies of evaluation were determined in 1989 by a questionnaire in a single medical school that had both a problem-based, student-centered curriculum and an organ-block curriculum (i.e., regular track). The greatest differences in the rankings of both areas were found between those given by the freshman and sophomore students in the problem-based curriculum and those given by the same groups in the regular track. The faculty members' perceptions tended to be closer to those of the students in the regular track.

Attitude to Health↗
PubMed1991

Pathologists and the autopsy.

Autopsy practice today remains rooted in the fabric of medicine as it developed through the 18th and 19th centuries. Recent developments in medicine and society have left autopsy practice behind and have led to the decline of the autopsy. Potential new values of autopsies point strongly to the need for revitalized modern autopsy services, services focused on objectives and problems related to patients, their physicians, and the attendant societal issues. There are real values for pathology and pathologists, but only if major realignments in purposes and outcomes are forthcoming.

Autopsy↗