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Biomedical subjects

G Brown

Publications and source records attributed to G Brown.

At least 379 records · Page 21Linked to original sources

Assessing the consultation: method for measuring changes in patient stress and arousal.

A method has been developed to assess anxiety levels in terms of stress and arousal in patients before and after a consultation with a general practitioner. The MACL self report mood scale has been used in hospital outpatient studies. An adaptation of the scale using 26 items of low vocabulary was applied to general practice patients in a novel way to show appreciable reductions in stress and increases in arousal after consultations. Since arousal is related to efficiency of performance and stress has been inversely related to recall of information given in the consultation factors that affect stress and arousal in patients could usefully be identified.

Adolescent↗

Assessing the consultation: methods of observing trainees in general practice.

We compared two different methods of observing trainees at work in general practice: the traditional one of a senior or training general practitioner sitting in during selected surgeries and the more modern video recording, with the patients' written consent. Patients who had experienced the presence of a second doctor during the consultation were less likely to show an increase in arousal after their consultations than those who had been recorded on video. Patients who refused consent to be recorded were more highly stressed than those who agreed and showed smaller decreases in stress after consultations. The presence of two doctors generated fewer reductions in stress after the consultation than video recording did, but this was a non-significant trend. The group that was recorded on video did not differ appreciably from a control group in changes in stress or arousal.

Arousal↗

Computers in the surgery. The patient's view.

A postal survey sent to 350 patients from two rural practices confirmed that an appreciable minority of patients (17%) were opposed to doctors using computers. The questionnaire distributed had been carefully designed to identify their opposition more specifically. Most of the general concern was accounted for by the 91 patients (31%) who feared that confidentiality of information would be reduced. The sensitive nature of medical information alerts patients to the possibility of diminished security of records and obliges practices considering acquiring a computer to ensure that these fears are not realised. Smaller proportions of patients were found to oppose computers on other grounds--namely, impersonality, economy, and general anxiety.

Adolescent↗

Maintenance of granulocyte-monocyte progenitor cells in liquid cultures of human foetal liver.

These studies describe a liquid suspension culture system for normal myeloid cells derived from human foetal liver. A simple one-step fractionation procedure was employed to obtain a cell population capable of expanding into all stages of myeloid differentiation, including committed myeloid progenitor cells (GM-CFC). Cell proliferation in these cultures resulted in the maintenance of early myeloid populations for up to a month. In order to extend myeloid cell maintenance, a specific factor in the form of media conditioned by human endothelial cells (endo C.M.) was used. Addition of endo C.M. to foetal liver cultures resulted in increased myeloid proliferation coupled to extensive myeloid differentiation. Clonally derived foetal liver culture cells proliferated for up to 2 months in the presence of endo C.M. before maturing into macrophages. These results show that endo C.M. exert an extensive proliferative effect on early myeloid cells as well as inducing their differentiation. The large quantity of cells in early stages of myeloid differentiation provided by foetal liver cultures may be useful for biochemical and molecular biology studies of myelopoiesis. In addition, these cultures are a potential source from which to derive normal myeloid lines. The separation of the potent proliferative activity present in endo C.M. may yield an effector which maintains human myeloid cell proliferation.

Cells, Cultured↗

A carbamylphosphate synthetase deficiency with no detectable immunoreactive enzyme and no translatable mRNA.

A lethal carbamylphosphate synthetase (CPS: EC 6.3.4.16) deficiency (McKusick 23730) was found in a newborn girl; who presented on the second day of life with acute hyperammonaemia, hypotonia, seizures and who died in a coma 6 days after birth. The activity of the mitochondrial urea cycle enzymes, CPS and ornithine transcarbamylase (OTC: EC 2.1.3.3) were measured on a needle biopsy sample taken from liver and showed that CPS was 1.4% of the normal mean (0.09 nmol/min/mg protein) whereas OTC activity was normal (110 nmol/min/mg protein). Immunological analysis of the liver sample showed no detectable immunoreactive CPS and confirmed the presence of normal levels of OTC. RNA was extracted from postmortem liver and in vitro translation experiments showed that there was no translatable CPS mRNA and confirmed that no CPS protein was synthesized in this child. The absence of translatable mRNA is explicable in terms of a genetic defect which results in a failure to synthesize mRNA for CPS, or synthesis of a defective form of mRNA which is not translated.

Amino Acid Metabolism, Inborn Errors↗

T-cell proliferation and expression of MHC class II antigens.

Two monoclonal antibodies to major histocompatibility complex (MHC) class II antigens, which in combination identify beta chains encoded by the SB and DR loci, were used to investigate which of these gene products were expressed at the cell surface of unstimulated T cells and at various stages of mitogen-induced T-cell maturation. In tests on blood lymphocytes from healthy donors 12% of T cells expressed class II antigens, but only SB antigens were expressed. During activation of T lymphocytes, SB-coded antigens were expressed before DR antigens, and the kinetics of SB expression correlated with the proliferative response of T cells. These results and consideration of recent reports from other laboratories lead us to suggest that SB-coded class II antigens play a role in T-cell proliferation.

Cells, Cultured↗

Mechanisms of depressed delayed-type hypersensitivity in rheumatoid arthritis: the role of protein energy malnutrition.

The presence of anergy and its relationship to malnutrition was investigated in patients with rheumatoid arthritis (RA) and in controls. A generalised reduction in delayed cutaneous hypersensitivity to 7 recall antigens were found in 104 RA patients compared with 67 controls. No measured of the disease was capable of predicting cutaneous anergy, which was present in 36% of patients but none of the controls. A detailed dietary assessment in 30 RA patients and 30 controls revealed little evidence of clinically important malnutrition. It is therefore concluded that the cutaneous anergy of rheumatoid arthritis is not a consequence of nutritional factors.

Adult↗

Widespread distribution in human tissues of an antigenic determinant of granulocytes.

The monoclonal antibodies AGF4 .48 and AGF4 .36 have previously been shown to distinguish human granulocyte lineage cells from other peripheral blood and bone marrow cells. The AGF4 .48 antigen, which is carbohydrate in nature, together with similar antigens described by numerous investigators have been considered specific differentiation antigens of myeloid cells. In immunohistological studies of a wide range of normal tissues, the AGF4 .48 antibody selectively stained cells in several apparently unrelated tissues. These included proximal tubules and descending thin limbs in the kidney, parietal cells in the stomach, a variety of other epithelial cells, astrocytes in the brain, and cells in the anterior pituitary containing adrenocorticotrophic hormone. The AGF4 .36 antibody gave similar results on kidney, stomach and pituitary. These findings emphasise the importance of assessing the binding of monoclonal antibodies, which appear unique in their reactivity with blood cells, to non-haemopoietic tissues before assigning specificity to reagents. The distribution of cells expressing the AGF4 .48 and AGF4 .36 antigen correlates with the occurrence of the 3-fucosyl-N-acetyllactosamine carbohydrate structure in various secreted glycoproteins.

Animals↗

A central apnoea extension alarm.

A central apnoea alarm designed to monitor the breathing of infants placed in four separate cubicles is described. It has been found to be effective and inexpensive, costing about 50 pounds.

Emergencies↗

Parasitologic and clinical features of bancroftian filariasis in a community in East Sepik Province, Papua New Guinea.

Bancroftian filariasis has been reported in several areas of Papua New Guinea. The epidemiologic features and natural history of Wuchereria bancrofti infection in this geographic region, however, have not been well-defined. The objective of this study was to assess the parasitological and clinical features of bancroftian filariasis in a community in East Sepik Province, Papua New Guinea. In a village of 99 individuals, the overall prevalence of microfilaremia was 68%. The microfilarial carrier rate was high in those less than or equal to 10 years (62%), remained elevated in the 11-20, 21-30, and 31-40 age groups (42-55%), and peaked in subjects greater than or equal to 41 years old (90%). The geometric mean level of parasitemia in all subjects with patent infection was 3,198 microfilariae/ml blood. This value was 78 parasites/ml in the less than or equal to 10-year-old age group, increased to 1,753 in 21 to 30-year-olds and was markedly elevated in subjects greater than or equal to 41 years old (6, 792 microfilariae/ml). Acute symptoms of filariasis (lymphadenitis and lymphangitis) were initially noted in individuals between the ages of 11 and 20 years (30%). Obstructive disease, manifested as elephantiasis and hydroceles, was present in 64 and 79% of 31-40 and greater than or equal to 41-year-olds, respectively. These data suggest that intense transmission of W. bancrofti infection occurs at an early age in this area of East Sepik Province; patent infection remains high in older age groups. Irreversible lymphatic obstruction develops 20-30 years after initial infection and may be associated with either amicrofilaremia or microfilaremia.

Adolescent↗

Mechanisms of rat pancreatic islet allograft rejection.

Since the mechanisms of rat islet allograft rejection are unknown, metabolic, histologic, and immunologic parameters were characterized during rejection. Syngeneic intraportal islet transplants in diabetic Lewis rats normalize glucose values without islet cellular infiltrates; after Wistar-Furth allografts, glucose values rapidly return to diabetic levels and infiltration of islets by mononuclear cells occurs. Using lymphocyte proliferative assays, allogeneic islets induce a 3-fold stimulation of lymphocytes derived from nondiabetic allograft recipients. Using cytotoxicity assays, cell-mediated cytotoxicity of allogeneic islet target cells although inefficient is 2-fold greater in diabetic allograft recipients than in syngeneic recipients. Antibody-dependent cellular cytotoxicity is not observed, whereas 14 days after allotransplantation, complement-dependent antibody-mediated cytotoxicity is elevated. These data suggest that islet allograft rejection using metabolic, histopathologic and immunologic methods is associated primarily with cell-mediated cytotoxicity related to histocompatibility antigens.

Animals↗

Effects of dietary manipulation on vascular status of patients with peripheral vascular disease.

In a one-year, double-blind clinical trial, 45 patients with peripheral vascular disease (PVD) were randomly assigned to either the American Heart Association Hyperlipidemia Diet C (n = 20) or a low-fat, high-fiber, complex carbohydrate diet similar to the Pritikin Maintenance Diet (n = 25). Vascular status and blood lipid levels were monitored at 0, 2, 4, 6, and 12 months. Walking distance increased significantly in both groups, with no difference between groups. No vascular parameters changed significantly, suggesting that increased walking distance was due to improved metabolic capacity of the muscle. A trend toward lower blood lipid values was observed, with no significant differences within or between groups. We conclude that while patients with PVD benefit from a program of diet and exercise, there is no apparent advantage to the more difficult complex carbohydrate diet.

Aged↗

Pineal modulation of ACTH 1-17 effect upon murine corticosterone production.

In tests of corticosterone production in vitro, aqueous pineal homogenate (APH) modulates the effect of a short-chain ACTH analogue, ACTH 1-17, added to adrenals from different circadian stages. Adrenal and pineal glands from female B6D2F1 mice, standardized on staggered LD 12:12 regimens, were obtained at the same clock-hour from each room, in order to cover 6 different circadian stages. Adrenals from each circadian stage were bisected and incubated with APH from the same circadian stage (isophasic incubation) or from one of the other 5 circadian stages (heterophasic incubation). ACTH 1-17 (0.05 IU) was added to each incubation medium. After 4 hours of incubation at 37 degrees C with 95% O2 and 5% CO2, the media were stored at -20 degrees C until corticosterone RIA were done. APH was found to have a statistically significant modulatory effect upon the stimulation by ACTH 1-17 of adrenal corticosterone production in vitro. This APH effect changed rhythmically as a function of circadian stage from amplification over no effect to attenuation, as a so-called feed-sideward.

Adrenal Glands↗

Antigen shared by human hemopoietic precursor cells and T and B lineage cells.

In this study, we investigated antigens present at the surface of acute myeloblastic leukemia (AML) cells by using the monoclonal antibody (MAb) approach. The MAb AGF43 reacted with acute myeloid and lymphoid leukemia cells and chronic lymphocytic leukemia cells and was unreactive against chronic myeloid leukemia cells. A large proportion of AML blasts showing minimal or no differentiation (AML-M1) were intensely labeled by AGF43 in contrast to a smaller percentage of blasts showing partial differentiation (AML-M2 and acute myelomonocytic leukemia). The AGF43 antigen is expressed by bone marrow lymphoid (TdT+) and myeloid (CFU-GM) progenitor cells, 95% of B cells and 65% of T cells in the blood and absent from monocytes. Only 17% of normal myeloblasts were weakly stained by AGF43. Sections of tonsil and spleen were used to confirm that, unlike antibodies to MHC class II antigens, AGF43 stained a majority of T cells and macrophages were unreactive. In conclusion, the MAb AGF43 identifies a new precursor cell antigen. The distribution of this antigen during normal myelopoiesis and on AML cells support the suggestion that acute myeloid leukemias originate in pluripotent or closely related myeloid stem cells.

Antibodies, Monoclonal↗

Transferrin receptors in human tissues: their distribution and possible clinical relevance.

The distribution of transferrin receptors (TR) has been studied in a range of normal and malignant tissues using four monoclonal antibodies, BK19.9, B3/25, T56/14 and T58/1. In normal tissues TR was found in a limited number of sites, notably basal epidermis, the endocrine pancreas, hepatocytes, Kupffer cells, testis and pituitary. This restricted pattern of distribution may be relevant to the characteristic pattern of iron deposition in primary haemachromatosis. In contrast to this limited pattern of expression in normal tissue, the receptor was widely distributed in carcinomas, sarcomas and in samples from cases of Hodgkin's disease. This malignancy-associated expression of the receptor may play a role in the anaemia of advanced malignancy by competing with the bone marrow for serum iron.

Adenocarcinoma↗