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Biomedical subjects

J Hall

Publications and source records attributed to J Hall.

At least 433 records · Page 24Linked to original sources
PubMed1985

Dietary fat and immune function. I. Antibody responses, lymphocyte and accessory cell function in (NZB x NZW)F1 mice.

The influence of dietary fat on autoimmunity in lupus-prone (NZB x NZW)F1 mice has been demonstrated. In defining further the effects of dietary lipid on the immune system of this strain, female weanling mice were placed on four diets differing in quantity and type of fat. Their immunologic response was then studied by a variety of tests at 4 and 7 mo of age. Few differences were seen among the four groups at 4 mo of age. At 7 mo of age, however, the mice receiving diets high in saturated and unsaturated fats had a reduced mitogenic response to T cell mitogens and an enhanced response to the B cell mitogen LPS. Immunoglobulin levels and delayed hypersensitivity responses did not show any consistent differences among the diet groups. At 7 mo, however, mice receiving diets high in unsaturated fat demonstrated hyperresponsiveness to injected sheep red blood cells as measured by the hemolytic plaque technique. In addition, peritoneal leukocytes from the same diet group exhibited an increased response to bromelain-treated autologous erythrocytes which was decreased after treatment with anti-Thy-1 antiserum and complement. Phagocytosis by peritoneal macrophages was significantly decreased in the animals fed high-fat diets, particular high saturated fat. Similarly, natural killer cell activity was markedly reduced in the mice with a high intake of saturated lipid, a finding which correlated with the in vitro production of interferon. These results indicate that diets high in fat influence immune responses and thus can affect the onset and severity of autoimmune disease. A low-fat diet can reduce the development of disease by maintaining normal immune responses. The data also suggest that unsaturated fat may influence T helper cell activity and therefore antibody production, whereas saturated fats may affect cellular immune responses which are dependent on membrane contact.

Animals↗
PubMed1985

Bacterial endosymbionts of Acanthamoeba sp.

Gimenez staining of presumably axenic Acanthamoeba sp., strain HN-3, showed rod-shaped cytoplasmic inclusions. Electron microscopy of thin sections of the amebae showed these to be bacilli which measured 1.3 to 3.3 microns by 0.22 to 0.33 micron. Their cell envelopes were those typical of gram-negative bacteria, surrounded by an electron-translucent area that stains with ruthenium red, suggesting the presence of a capsule. The bacilli grew and reproduced in the cytoplasm of both trophozoites and cysts of Acanthamoeba sp. There was no evidence of a surrounding phagosomal or phagolysosomal membrane. They were retained by the ameba both during encystment and excystment. All attempts to isolate the endosymbionts in embryonated eggs and/or standard bacteriological media failed; and they persisted within the amebae for 1 to 6 mo despite temperature shocking or constant treatment of cultures with penicillin, streptomycin, chloramphenicol, tetracycline, erythromycin, polymyxin B, ampicillin, isoniazid, rifampicin, or gentamycin at concentrations of 10(-5) to 10(-3) M.

Amoeba↗
PubMed1985

Motor proficiency in depressed adolescent inpatients: biochemical and clinical diagnostic correlates.

A pilot investigation was conducted on 25 adolescents, ages 11 to 18 years, admitted to a six-bed psychiatric unit in a university hospital in order to explore relationships among motor proficiency and categories of depressive illness. The investigators endeavored to determine whether (a) depressed adolescents would perform as well as normals on the Bruininks-Oseretsky Test of Motor Proficiency and (b) whether the method of diagnosing major depressive episode (MDE), using DSM-III criteria or the Dexamethasone Suppression Test, was related to motor proficiency. Results indicate that depressed adolescents performed less well on balance, bilateral coordination, upper limb coordination, and response speed than normals. Major depressive episode (MDE) patients, as defined by the Dexamethasone Suppression Test, performed less well than patients with Adjustment Disorder with Depressive Mood. Patients diagnosed as MDE on the basis of DSM-III criteria had motor proficiency scores similar to those of the other patients with depressive mood adjustment disorders. The method of diagnosis is critical if prescribed physical activity therapy is to be effective.

Adolescent↗
PubMed1984

An in vitro approach to studying cutaneous metabolism and disposition of topically applied xenobiotics.

The extent to which cutaneous metabolism may be involved in the penetration and fate of topically applied xenobiotics was examined by metabolically viable and structurally intact mouse skin in organ culture. Evidence that skin penetration of certain chemicals is coupled to cutaneous metabolism was based upon observations utilizing [14C]benzo[a]pyrene (BP). As judged by the recovery of radioactivity in the culture medium 24 hr after in vitro topical application of [14C]BP to the skin from both control and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced C3H mice, skin penetration of BP was higher in the induced tissue. All classes of metabolites of BP were found in the culture medium; water-soluble metabolites predominated and negligible amounts of unmetabolized BP were found. As shown by enzymatic hydrolysis of the medium, TCDD induction resulted in shifting the cutaneous metabolism of BP toward the synthesis of more water-soluble conjugates. Differences in the degree of covalent binding of BP, via diol epoxide intermediates to epidermal DNA, from control and induced tissues were observed. These differences may reflect a change in the pathways of metabolism as a consequence of TCDD induction. These results indicated that topically applied BP is metabolized by the skin during its passage through the skin; and the degree of percutaneous penetration and disposition of BP was dependent upon the metabolic status of the tissue. This suggests that cutaneous metabolism may play an important role in the translocation and subsequent physiological disposition of topically applied BP.

Administration, Topical↗
PubMed1984

An economic model of general practice.

The public perceives that doctors earn too much, while general practitioners complain that their income is dwindling . In the absence of reliable data on doctors' incomes, it is impossible to determine whether medical fees are set appropriately, and what effects Medicare might have on general practice. An economic model of practice, using estimates of income and expenditure derived from specified assumptions, was constructed. Then, the effects of changes in various parameters of the model were examined in turn to show how economic forces are likely to affect the behaviour of doctors. It is shown that a general practitioner working at a moderate rate during a normal working week will earn a low income under current schedule fees. Some implications of these findings for practitioners, fee setting, and the public are explored.

Aged↗
PubMed1984

Immunocytochemical localization of mouse placental lactogen in the mouse placenta.

The localization of mouse placental lactogen (mPL) in the mouse placenta has been examined with the avidin-biotin-peroxidase complex (ABC) technique. Staining was observed to occur in the basal zone of placentae from days 10, 12, 15, and 18 of gestation. Within the basal zone, the most prominent staining was localized to the cytoplasm of the giant cells. Within the labyrinth, staining was observed in the giant cells in day-15 and day-18 placentae, with a greater number of stained cells being observed in the latter.

Animals↗
PubMed1984

Methodological standards in studies evaluating the dexamethasone suppression test.

The dexamethasone suppression test (DST) has been used for several years to assist in the diagnosis of melancholia. However, recent studies have cast doubt upon the diagnostic efficacy of the test. Twenty of the original studies that assessed this application of the DST were reviewed using six methodological criteria considered essential for the evaluation of a diagnostic test. None of the papers complied with all the criteria and only seven of the papers satisfied more than three criteria. These findings suggest that methodological problems might account for discrepancies between the original claims made for the test and the current status of the test.

Depressive Disorder↗
PubMed1984

A rapid sensitive assay for the quantitation of elastin.

A rapid, sensitive and direct assay was developed for the quantitation of elastin using reverse phase high performance liquid chromatography. The method is based on the separation of the alkaline hydrolysis-resistant dipeptide valyl-proline, a dipeptide found in high concentrations in elastin. The methodology is applicable to unlabelled elastin samples in the range of 10-100 micrograms utilizing fluorescamine detection and to hot alkali insoluble as well as soluble forms of elastin. Increased sensitivity was achieved by the use of in vitro radiolabelling of elastin with [3H]proline. This was useful for following synthesis of elastin in cultured cells. Since this technique is not dependent on detection of the elastin-specific crosslink groups, desmosine and isodesmosine, precursor forms of elastin can be measured as well as other forms of elastin deficient in cross-linking. The same chromatographic procedure however, is able to detect these desmosine and isodesmosine crosslinks. Therefore, in cell cultures under the proper radiolabelling conditions, biosynthesis and cross-linking of elastin can be followed simultaneously in a single chromatographic procedure.

Animals↗
PubMed1984

The matrix of human breast tumor cells is mitogenic for fibroblasts.

The basis of the scirrhous reaction to human breast carcinoma was investigated. When normal human skin fibroblasts were plated on the preformed extracellular matrix of human breast tumor cells, a remarkable series of changes was observed. The matrix of the tumor cells was mitogenic for the fibroblasts. An increased growth rate and a fourfold increase in cell density was observed. There was also a change in cell morphology and in the pattern in which the cells grew, with an apparent loss of contact inhibition. The spindle-shaped fibroblasts became more elliptical and grew in a series of whorls and dense ridges with spaces between them. These observations were made with the use of newborn foreskin fibroblasts and the matrix of an established line of human breast cancer cells, ZR75-1. No such effect was seen when fibroblasts were plated on their own preformed matrix, on the matrixes of other cell types, on various type-specific collagen gels, or on a combination of collagen and fibronectin or when fibroblasts were grown in media conditioned by the ZR75-1 cells. A floating tumor cell matrix added to the cell media also did not provide the mitogenic stimulus. Apparently, fibroblasts required direct contact with the tumor cell matrix for the mitogenic response to occur. In vivo, the matrix of breast tumor cells may modulate the growth and the morphology of host stromal cells. Collagen is a major synthetic product of fibroblasts. The stimulation of stromal cells to proliferate by adjacent breast tumor matrix may be the basis of the desmoplastic reaction, the intense fibrotic response associated with human breast cancer.

Breast Neoplasms↗
PubMed1984

Dietary intakes of preschoolers.

Between 1977 and 1979, the H.J. Heinz Company of Canada Ltd conducted a longitudinal survey of infant nutrition from birth to 18 months. In 1980, 189 of the original 403 infants were recruited in a follow-up study. The age of the children in the follow-up study was 3.5 to 4 years. This article describes the food and nutrient intakes of the preschool children. Food intake information was obtained by the 4-day dietary record method. The mean energy intake of the children was adequate to support normal growth. The mean nutrient intakes were above the recommended daily intakes of the Canadian Dietary Standard. All children ate three regular meals and at least one in-between meal snack. Milk was the primary source of energy, protein, fat, calcium, phosphorus, sodium, potassium, and riboflavin. Meat contributed a substantial amount of protein, fat, and niacin. Cereal and cereal products were the primary source of iron and were good sources of carbohydrates, sodium, and the B vitamins. Fruit and fruit juices were the primary sources of carbohydrate and vitamin C. Vitamin supplements provided large amounts of vitamin A and the B vitamins. Since foods alone included sufficient nutrients to provide the recommended daily nutrient intakes, vitamin supplements were largely unnecessary.

Child Nutritional Physiological Phenomena↗