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Biomedical subjects

G Brown

Publications and source records attributed to G Brown.

At least 415 records · Page 23Linked to original sources
PubMed1980

A prospective study of children with head injuries: I. Design and methods.

The main unresolved issues with respect to the psychological sequelae of brain damage in childhood are noted, and the previous studies of children suffering head injury are critically reviewed. A new prospective study is described. Three groups of children were studied: (a) 31 children with "severe" head injuries resulting in a post-traumatic amnesia of at least 7 days; (b) an individually matched control group of 28 children with hospital-treated orthopaedic injuries; and (c) 29 children with "mild" head injuries resulting in a post-traumatic amnesia exceeding 1 hour but less than 1 week. The children were studied as soon as possible after the accident and then again 4 months, 1 year, and 2 1/4 years after the injury. The parents were interviewed, using systematic and standardized interview techniques; both parents and teachers completed behavioural questionnaires; and the children were seen for individual psychological testing the WISC, the Neale Analysis of Reading Ability and a battery of tests of more specific cognitive functions. At the final follow-up, the severe head injury group (but not the other 2 groups) received a systematic neurological examination and the school teacher who knew the child best was personally interviewed. The findings are given on physical handicap, neurological abnormality, school placement and psychiatric referrals. All types of disabilities were both more frequent and more persistent in the children with severe head injuries.

Amnesia↗
PubMed1980

Angiotensin II receptors and in vitro aldosterone responses of aldosterone-producing adenomas, adjacent nontumorous tissue, and normal human adrenal glomerulosa.

Angiotensin II (angio II) receptors have been compared using tissues from aldosterone-producing adenomas (APAs), adjacent nontumorus tissue, and normal human adrenal glomerulosa. Plasma membrane-rich subcellular fractions were employed in a radioreceptor assay with [125I]angio II. In vitro aldosterone secretory response to angio II were determined using isolated cells obtained by collagenase digestion. Results are reported as the mean +/- SE. Normal glands have high and low affinity receptor sites for angio II. The Ka values for a normal adrenal obtained at surgery were 2.5 and 0.4 nM-1, while autopsy adrenals were 1.1 +/- 0.4 and 0.3 +/- 0.15 nM-1 (n = 3). APAs and adjacent nontumorous tissue possessed only low affinity receptor sites (0.22 +/- 0.05 nM--1; n = 11). The receptor concentration for a surgically obtained adrenal was 1562 fmol/mg protein, contrasted with 466 +/- 135 from autopsy adrenals. APA and adjacent tissue bound 462 +/- 112 fmol/mg protein. Cells from seven of eight APAs produced aldosterone when stimulated by angio II (3 x 10(-10)-10(-6) m). The increments were 16-105% above basal levels. The response were similar to but less senstive than cells from normal adrenals. The only tumor that failed to respond had 1/50th of the receptors of the other APAs. In contrast, only three of seven adjacent tissues responded, and then only negligibly. ACTH (10(-8) M) increased aldosterone production by APAs 10-158%, by normal cells 283% and by three of six adjacent nontumorous tissues 170-400%. The observations that APAs have angio II receptors and aldosterone responses to angio II is consistent with the fact that some patients with APA have postural increments of plasma posture. The presence of receptors of adjacent tissue and no in vitro response suggest a defect in the aldosterone biosynthetic pathway as a cause of the prolonged absence of response to angio II after removal of APAs.

Adenoma↗
PubMed1980

Group B beta-hemolytic streptococcus: randomized controlled treatment study at term.

A randomized controlled investigation was undertaken to evaluate the role of maternal oral antibiotic therapy in decreasing the incidence of maternal and neonatal colonization at term with group B beta-hemolytic streptococcus (GB-BHS). Data were collected to determine the optimum transfer media and the colonization rate in the study population. At delivery 1441 maternal-infant pairs were evaluated. One hundred sixty-eight women (11.6%) and 55 infants (3.8%) were colonized. Forty-four women colonized with GB-BHS at 38 weeks' gestation were randomly assigned to a treatment (500 mg potassium penicillin or erythromycin ethylsuccinate q.i.d.) or a control group to determine the value of antepartum oral antibiotic therapy in preventing infant colonization. There was a significant reduction in maternal (P = 0.008) and infant (P = 0.004) colonization rates in the treatment group. There were no observed complications of antibiotic therapy in mothers or infants. This study suggests that routine cultures for GB-BHS should be done at 38 weeks' gestation. Mothers colonized at this time may be considered candidates for prophylactic antibiotic treatment.

Carrier State↗
PubMed1980

Plasmodium falciparum strains from Papua New Guinea: culture characteristics and drug sensitivity.

Seven strains of Plasmodium falciparum from Papua New Guinea have been established in continuous in vitro culture. Samples with a high initial parasitaemia were more likely to form continuous lines, possibly due to the time required for transport of infected blood samples from Papua New Guinea to laboratories in Australia. Most but not all established lines were resistant to chloroquine and all were resistant to pyrimethamine, possibly reflecting the parasite strain characteristics in that region.

Adolescent↗
PubMed1980

Immunosuppression in BALB/c mice bearing the plasmacytoma TEPC-183: massive increase in red pulp macrophages induced by the tumour.

An increase was found in total macrophage numbers in the spleens of BALB/c mice bearing the plasmacytoma TEPC-183 compared with controls. The increase was shown to be confined to red pulp macrophage; white pulp macrophage numbers were normal as were the number of macrophages which took up hydroxyethyl starch. It is suggested that this increase in red pulp macrophages may account for the suppression of primary immune responses caused by spleen cells from TEPC-183 bearing mice. This effect may be due to increased numbers of normal macrophages rather than the generation of distinctive suppressor macrophages as suggested previously.

Animals↗
PubMed1979

Immune suppression in BALB/c mice bearing the plasmacytoma TEPC-183: evidence for normal lymphocyte but defective macrophage function.

This paper analyses impairment of the primary immune response of mice bearing the plasmacytoma TEPC-183. Healthy animals and mice bearing the reported non-immunosuppressive tumour MOPC-104E were used as controls. The defect was shown to affect both primary IgG and IgM responses to chicken cells (CRBC) and to be related to tumour size. However, the primary immune depression could be overcome either by increasing the antigen dose or by using Freund's complete adjuvant together with antigen. Secondary responses were also depressed. This depression was more pronounced if the animals was primed after, rather than before, tumour implantation. Further studies involved the measurement of primary immune responses of immunologically deprived syngeneic mice, after they had been reconstituted with cells from normal or tumour-bearing mice. Lymphocyte reconstitution experiments were carried out in mice which had been irradiated with 950R. Various lymphoid preparations from TEPC-183-bearing mice were unable to bring about such restoration. It is concluded that the impairment of the primary immune response of mice bearing the plasmacytoma TEPC-183 is due to a macrophage, rather than a lymphocyte, abnormality. However, none of these transfer studies suggested that positive suppression of primary immune responses was being mediated by cells from TEPC-183-bearing mice.

Animals↗
PubMed1979

The carbohydrate prosthetic groups of rat fibrinogen plasmic fragment E.

Rat fibrinogen plasmic fragment E was found to contain one oligosaccharide chain per gamma-chain attached by a glycosylamine linkage. The oligosaccharide was composed of 1 sialic acid, 1 galactose, 2 mannose and 2 glucosamine residues. The probable sequence from the nonreducing end was sialic acid leads to galactose beta leads to mannose alpha leads to mannose alpha leads to glucosamine leads to glucosamine. No difference in the rate of clearance from the rat circulation could be detected between native and desialated fragment E. A non-denaturing method for the purification of fragment E is described.

Animals↗
PubMed1979

The distribution of HLA on human lymphoid, bone marrow and peripheral blood cells.

The cellular distribution and the differential expression of HLA on cell suspensions and tissue sections has been investigated using the monoclonal antibody W6-32, which reacts with the high molecular weight chain of the major histocompatibility antigen. Lymphocytes and platelets, as assessed by autoradiographic and immunoperoxidase labeling, were the most densely labeled cells. Myeloid precursors showed more labeling than mature neutrophils. Electron microscopic immunoperoxidase labeling showed a continuous distribution of HLA antigen on lymphoid and myeloid cell membranes. Erythroid precursors (including reticulocytes), although very weakly labeled, were clearly positive, in comparison with mature erythrocytes. In the thymus, HLA-negative, thymocyte antigen-positive cells (85%) can be distinguished from HLA-positive, thymocyte antigen-negative cells (15%). By using immunofluorescence techniques on tissue sections, the former cells were shown to be cortical thymocytes and the latter medullary cells.

Antigens, Surface↗
PubMed1979

Antibodies in human sera reacting with an insect pathogenic virus.

Precipitating antibodies to an insect pathogenic RNA virus of Darna trima from East Malaysia have been found in a small percentage of human sera from several different groups of persons in West Malaysia and the United Kingdom. No associated illness was identified. The results suggest that an antigenically related virus or viruses are present in the environment that may be associated with symptomless or inapparent infections in man.

Adolescent↗