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Biomedical subjects

J Harris

Publications and source records attributed to J Harris.

At least 361 records · Page 20Linked to original sources
PubMed1988

Measurement of gamma-interferon in culture supernatants of antigen-stimulated lymphocytes from patients with Schistosoma mansoni infections by a reverse passive haemagglutination assay.

An assay for gamma-interferon (IFN gamma) in human lymphocyte culture supernatants, based on reverse passive haemagglutination (RPH) of red cells bearing a monoclonal anti-IFN gamma antibody, was developed and compared with a conventional virus inhibition assay. Test samples comprised supernatants of lymphocytes from patients with Schistosoma mansoni infections, cultured with or without a soluble worm antigen preparation. The two assays gave comparable results, the correlations for individual samples being good. The RPH assay was both specific and sensitive, allowing the detection of IFN gamma at 13 u/ml (1 ng/ml) or less. The advantages of the RPH assay were that it was quick, relatively inexpensive and suitable for testing large numbers of samples. In particular, between-experiment variation was very low, allowing the assay of different samples on different occasions.

Adolescent↗
PubMed1988

Synthesis of eicosanoids by gamma-interferon-differentiated U937 cells.

Interferons induce morphological, biochemical and functional alterations in monocyte macrophage and myeloid cell lines. We studied the effect of 3 days incubation with gamma-interferon from human buffy coats on the global synthesis of arachidonic acid metabolites by U937 cells. Interferon-induced morphologic changes including cytoplasmic and nuclear changes and the appearance of multiple lysosomal-like granules consistent with cellular differentiation were observed by electron microscopy. The labeling of phosphatidylserine, phosphatidylcholine and phosphatidylethanolamine was increased and that of phosphatidylinositol, free fatty acids as 3H-arachidonic acid and neutral lipids reduced, when interferon-treated cells were incubated with 3H-arachidonic acid. Interferon caused qualitative and quantitative changes in the synthesis of cyclooxygenase and lipoxygenase products. A23187, a calcium ionophore, and the tumor promotor, phorbol myristate acetate, greatly increased the synthesis by interferon-differentiated cells of 2 cyclooxygenase products; synthesis of lipoxygenase products was reduced. In the presence of indomethacin, 'shunting' into putative lipoxygenase products occurred. The relationship between interferon-induced morphologic and functional changes, the development of altered phospholipid and eicosanoid metabolism and the identity of these metabolites are yet to be established.

Cell Differentiation↗
PubMed1988

Preadolescent attitudes toward the elderly: an analysis of race, gender and contact variables.

Preadolescent attitudes toward the elderly were examined through analysis of race, gender, and contact variables. Subjects were randomly selected preadolescents (mean = 12.8 years), a total of 157 students (91 boys and 66 girls), comprising three ethnic groups (49% white, 30% Mexican-American, 21% black). The investigator instructed each student to complete the Tuckman-Lorge Old People Scale, and a self-report contact questionnaire, thereby establishing three contact groups (high, medium, low). Data were analyzed via an ANOVA. The results revealed that only one of the variables studied, race, was significantly related to attitudes toward the elderly. The white preadolescents possessed the most positive attitudes toward the elderly. The greatest differences were between the white and black female preadolescents. These results suggest that preadolescent attitudes toward the elderly are culturally related. It can be concluded that as a variable, race should receive more attention in future attitudinal studies of the preadolescent.

Adolescent↗
PubMed1987

Secular rates and correlates for gastroschisis in California (1968-1977).

This study reports on an epidemiological investigation of gastroschisis using birth certificate data from California for the period of 1968-1977. Gastroschisis has been reported to be on the increase in a number of countries. The distribution of the 166 California gastroschisis cases reported during this time period indicated a clear upward secular trend (P less than .001) with the rate per 1,000 increasing from .006 in 1968 to .089 by 1977. This secular trend was observed in every maternal age group and for gravidity level 1. Gastroschisis also occurred more frequently among younger mothers (P less than .001) and low gravidity mothers (P less than .001). Omphalocele, another eventration defect, was also examined but did not display an upward secular trend.

Abdominal Muscles↗
PubMed1987

Alcohol and adolescence.

Alcohol is the drug of choice for most substance-abusing adolescents and is the drug most often associated with teenage deaths. This article summarizes what is known about the inheritance of alcohol abuse, as well as the physical, developmental, psychosocial, and behavioral factors related to adolescent alcohol use.

Adolescent↗
PubMed1987

Measurement characteristics of the mental health scale from the OARS. Older Americans Resources and Services.

Psychometric properties of the mental health scale from the OARS, which is also called the Short Psychiatric Evaluation Schedule (SPES), were explored in a large (N = 2015) cross-sectional sample ranging in age from 26 to 86 years. Results indicated that the 15 SPES items represented three distinctive factors--alienation, somatic symptoms, and depression. Only on somatic symptoms was there a pattern of greater endorsement by older respondents. The results illustrate that global test scores can be misleading, especially when applied to different age groups.

Adult↗
PubMed1987

QALYfying the value of life.

This paper argues that the Quality Adjusted Life Year or QALY is fatally flawed as a way of priority setting in health care and of dealing with the problem of scarce resources. In addition to showing why this is so the paper sets out a view of the moral constraints that govern the allocation of health resources and suggests reasons for a new attitude to the health budget.

Ethics, Medical↗
PubMed1987

Teaching medical ethics symposium. Medical ethics in Manchester.

Manchester's multi-disciplinary approach to medical ethics combines established methods and new initiatives. There is a longstanding Medical Group and also, plans are evolving for the inclusion of medical ethics teaching in the undergraduate curriculum, the start of an MA in Health Care Ethics in October 1987 and the establishment of the Centre for Social Ethics and Policy to act as a focus within the university for research and study in a wider context.

Curriculum↗
PubMed1987

Protection by thymidine, an inhibitor of polyadenosine diphosphate ribosylation, of streptozotocin inhibition of insulin secretion.

It has been suggested that a result of streptozotocin (Sz)-initiated damage to beta-cell DNA is activation of the repair enzyme nuclear poly-ADP-ribose (p-ADPR) synthetase and subsequent depletion of cellular NAD. This reduction of NAD is presumed responsible for the impaired islet function. Using freshly isolated rat pancreatic islets, we have examined the ability of p-ADPR synthetase inhibitors, in particular the previously not studied thymidine, to block Sz-induced damage to the B cell. Islets were incubated in 2 mM glucose and 2 mM Sz with or without p-ADPR synthetase inhibitor and then challenged for 1 h with 25 mM glucose plus 25 microM forskolin or 100 nM phorbol ester without glucose. Sz treatment inhibited insulin secretion about 90% even when stimulated by the non-glucose-containing challenge, indicating that Sz caused a rapid and generalized lesion past glucose-specific signals. Thymidine maintained the insulin secretory response to glucose plus forskolin from Sz-treated islets as, or more, effectively than nicotinamide. In a dose-dependent manner, thymidine protected Sz-treated islets to 87% of normal islet secretion at the highest thymidine dose (20 mM). However, even protected islets could not sustain normal secretion; insulin secretion was significantly diminished in thymidine-protected islets challenged with a second consecutive 1-h glucose plus forskolin stimulus. As expected, the acute depletion of islet NAD content (approximately 50%, 1 h after Sz) was reversed to 90% of normal by thymidine. However, even in unprotected Sz-treated islets, NAD content gradually recovered over 48 h of culture in standard RPMI, although insulin secretion remained suppressed. Thus, thymidine may be a useful protective agent against chemically induced islet cell damage. Furthermore, a sustained suppression of NAD content does not explain Sz's permanent inhibition of islet secretory response. Other aspects of inhibited nuclear p-ADP-ribosylation are considered to explain protection against Sz damage to the beta-cell.

Animals↗
PubMed1987

Magnification factor for adaptation of a visual transient mechanism.

After adaptation by an observer to a patch of gradually increasing (or decreasing) luminance, a steady test patch appeared to be gradually dimming (or brightening). These aftereffects did not transfer interocularly. Adaptation to a checkerboard, in which the white squares gradually dimmed while the black squares gradually brightened, gave an aftereffect that was a pattern of intersecting diagonal lines, that is, an extremely blurred checkerboard. The larger the squares of the checkerboard were, the farther into the periphery the aftereffect extended, because small squares were blurred out by the summation areas of the underlying visual channels, which were larger at increasing eccentricities and had diameters of 20 times the resolvable dot separation. The estimated visual acuity of these channels was as low as 20/400. These estimates were confirmed by manipulating separately the local and space-averaged luminances of the adapting stimulus.

Acclimatization↗
PubMed1987

Aqueous-organic solvent extraction of water-insoluble protein from ragweed pollen.

A water-insoluble material was obtained from either short ragweed (Ambrosia elatior) or false ragweed (Franseria acanthicarpa) pollen extracted by organic solvent (50% N,N-dimethylformamide). Further investigation of this water-insoluble material showed it contained at least five proteins. Two of them were isolated and shown to possess antigenicity as well as allergenicity. RFA2 contains carbohydrate and is a glycoprotein. RFB2 not only possesses antigenic determinants found in the water-soluble antigens AgE, AgK and Ra3, but also contains a separate and unique antigenic determinant. Immunodiffusion tests of RFB2, isolated from false ragweed and short ragweed, showed immunological identity. This communication further supports the suggestion that aqueous-organic solvent systems may be useful for the extraction of the biologically-active protein components from short ragweed pollen which can not be obtained with the currently used standard aqueous buffer system.

Allergens↗
PubMed1986

Formation of 8-hydroxydeoxyguanosine, hydroxyl free radical adduct of DNA in granulocytes exposed to the tumor promoter, tetradecanoylphorbolacetate.

The exposure of human granulocytes to the tumor promoter, tetradecanoylphorbolacetate (TPA), resulted in the accumulation of 8-hydroxydeoxyguanosine (8-OHdG) in the DNA of the treated cells. Hydroxyl free radicals react with DNA causing the hydroxylation of guanine at the C-8 position. The modified nucleoside (8-OHdG) cleaved from DNA, was quantitated at subpicomole levels utilizing high pressure liquid chromatography with electrochemical detection (LCED). Superoxide dismutase and catalase caused a marked decrease in the levels of 8-OHdG in the cellular DNA. The level of 8-OHdG formed by TPA stimulation of granulocytes was equivalent to one modified guanine for about every 600 possible guanines in the cellular DNA.

8-Hydroxy-2'-Deoxyguanosine↗