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Biomedical subjects

W Boyle

Publications and source records attributed to W Boyle.

At least 19 recordsLinked to original sources
PubMed1996

Skin testing with Mycobacterium avium sensitin to identify infection with M. avium complex in patients with cystic fibrosis.

We sought to determine if patients with cystic fibrosis and sputum cultures positive for Mycobacterium avium complex (MAC) have delayed-type hypersensitivity to an M. avium sensitin. Seventeen (33%) of 51 selected patients had MAC isolated from at least one sputum culture. Skin tests with purified protein derivative and M. avium sensitin demonstrated that five (10%) of 51 patients were anergic, and anergy was correlated with use of systemic steroids. Sixteen (35%) of 46 nonanergic patients had M. avium-dominant skin test reactions. Twelve (75%) of these 16 patients with cultures positive for MAC had M. avium-dominant skin tests; the specificity of skin testing was 87%. These data suggest that most patients with cystic fibrosis and sputum cultures positive for MAC have infection rather than colonization with MAC. Skin testing with M. avium sensitin is a sensitive and specific method for screening these infections.

Adolescent↗
PubMed1996

Dual actions of halothane on intracellular calcium stores of vascular smooth muscle.

BACKGROUND: Halothane has been reported to affect the integrity of intracellular Ca2+ stores in a number of tissues including vascular smooth muscle. However, the actions of halothane on intracellular Ca2+ stores are not yet fully understood. METHODS: Employing the isometric tension recording method, the action of halothane in isolated endothelium-denuded rat mesenteric arteries under either intact or beta-escinmembrane-permeabilized conditions was investigated. RESULTS: Halothane (0.125-5%) produced concentration-dependent contractions in Ca2+ free solution in both intact and membrane-permeabilized muscle strips. Ryanodine treatment or repetitive application of phenylephrine eliminated both caffeine-and halothane-induced contractions in the Ca2+ free solution. When either halothane and caffeine, caffeine and halothane, phenylephrine and halothane, or inositol 1,4,5-triphosphate and halothane were applied consecutively in the Ca2+ free solution in either intact or membrane-permeabilized muscle strips, the contraction induced by application of the second agent of the pair was inhibited compared to application of that agent alone. However, when procaine was applied before and during application of the first agent, the contraction induced by the first agent was inhibited and the contraction induced by the second agent was restored. Heparin inhibited the inositol 1,4,5-triphosphate-mediated contraction, but not contractions induced by halothane or caffeine. Halothane (0.125-5%), applied during Ca2+ loading, produced concentration-dependent inhibition of the caffeine contraction (used to estimate the amount of Ca2+ in the store) in both intact and membrane-permeabilized muscle strips. In contrast, halothane applied with procaine during Ca2+ loading produced concentration-dependent enhancement of the caffeine contraction. This enhancement was observed only in the intact but not in the membrane-permeabilized condition. CONCLUSIONS: Halothane has two distinct actions on the intracellular Ca2+ stores of vascular smooth muscle, a Ca2+ releasing action and a stimulating action on Ca2+ uptake. Halothane releases Ca2+ from the stores that are sensitive to both caffeine/ryanodine and phenylephrine/inositol 1,4,5-triphosphate through a procaine-sensitive mechanism. The observed inhibitory effect on Ca2+ uptake is probably caused by the Ca2+ uptake after blockade of Ca2+ release may be membrane-mediated.

Anesthetics, Inhalation↗
PubMed1995

Susceptibility of human monocytes to HIV type 1 infection in vitro is not dependent on their level of CD4 expression.

Monocytes from HIV-seronegative persons were analyzed for CD4 expression and susceptibility to infection with HIV-1 on the day of isolation and following 1, 2, and 7 days in culture. Although surface CD4 was readily detected on freshly isolated monocytes, these cells were relatively resistant to infection. After 1 to 2 days in culture, when surface expression of CD4 had decreased over 90% to near background levels, cells became susceptible to infection with HIV-1. CD4 expression on monocytes cultured for 7 days was more than four times higher than that on freshly isolated cells, and the cultured cells were fully permissive to infection. These observations suggest that the differing susceptibility of monocytes and monocyte-derived macrophages to infection with HIV-1 is not simply proportional to the level of surface CD4 expression.

Antigens, CD↗
PubMed1994

Keratinocyte growth factor induces proliferation of hepatocytes and epithelial cells throughout the rat gastrointestinal tract.

Keratinocyte growth factor (KGF), a member of the fibroblast growth factor (FGF) family, was identified as a specific keratinocyte mitogen after isolation from a lung fibroblast line. Recently, recombinant (r)KGF was found to influence proliferation and differentiation patterns of multiple epithelial cell lineages within skin, lung, and the reproductive tract. In the present study, we designed experiments to identify additional target tissues, and focused on the rat gastrointestinal (GI) system, since a putative receptor, K-sam, was originally identified in a gastric carcinoma. Expression of KGF receptor and KGF mRNA was detected within the entire GI tract, suggesting the gut both synthesized and responded to KGF. Therefore, rKGF was administered to adult rats and was found to induce markedly increased proliferation of epithelial cells from the foregut to the colon, and of hepatocytes, one day after systemic treatment. Daily treatment resulted in the marked selective induction of mucin-producing cell lineages throughout the GI tract in a dose-dependent fashion. Other cell lineages were either unaffected (e.g., Paneth cells), or relatively decreased (e.g., parietal cells, enterocytes) in rKGF-treated rats. The direct effect of rKGF was confirmed by demonstrating markedly increased carcinoembryonic antigen production in a human colon carcinoma cell line, LIM1899. Serum levels of albumin were specifically and significantly elevated after daily treatment. These results demonstrate rKGF can induce epithelial cell activation throughout the GI tract and liver. Further, endogenous KGF may be a normal paracrine mediator of growth within the gut.

Animals↗
PubMed1993

Childhood injury prevention counseling in primary care settings: a critical review of the literature.

OBJECTIVES: The American Academy of Pediatrics (AAP) believes that health education, through office-based counseling, can contribute to childhood injury prevention. This report presents the results of a critical review of the scientific literature on the effectiveness of primary care-based counseling to prevent childhood unintentional injury. METHODS: A panel selected from the AAP Committee and the AAP Section on Injury and Poison Prevention searched the English-language scientific literature for all articles about childhood unintentional injury prevention counseling. A standardized format was developed to record data on each study. Two members of the panel independently reviewed each article. Articles that were original reports and in which unintentional injury prevention counseling took place in a primary care setting were included. Articles were encoded and analyzed by computer and then grouped by quality of evidence using the US Preventive Services Task Force (USPSTF) method of categorizing results of medical care evaluation. Articles were rated by strength of study design in order to compare studies within each USPSTF group. RESULTS: Twenty articles met the criteria for inclusion. Of these, 18 showed positive effects of injury prevention counseling including five randomized/controlled, 10 non-randomized/controlled, two multiple time series, and one descriptive study. In 15 of the positive studies, physicians performed the counseling. Positive outcomes as measured by increased knowledge, improved behavior, or decreased injury occurrence were reported for both motor vehicle and non-motor vehicle injuries. CONCLUSIONS: The literature review supports the recommendation of the AAP to include injury prevention counseling as part of routine health supervision. This recommendation has implications for health care reimbursement and care content.

Accident Prevention↗
PubMed1990

Class II MHC antigen-positive macrophages from human placentae suppress strong MLR and CML reactions.

Placental adherent cells (PAC), derived by mild enzymic digestion of human placentae and adherence to plastic, were tested for their ability to suppress MLR and CML reactions. Stimulation of allogeneic T cells by cord blood mononuclear cells or by a strongly stimulatory B lymphoblastoid cell line were consistently inhibited by all PAC preparations tested. PAC were fractionated by Fc rosetting and Percoll gradients to produce a number of bands. Suppression correlated with the content of macrophages in each band and was strongest in band 5 which generally contained 94-100% macrophages. The suppressive effect was not inhibited by indomethacin. The possible role of macrophages in suppressing immune reactivity in the placenta is discussed.

Cell Separation↗
PubMed1989

Electrocardiographic and hemodynamic effects of intravenous cocaine in awake and anesthetized dogs.

Graded bolus and infusion doses of cocaine were given to 18 dogs, 6 under general anesthesia and 12 awake, to determine the range of hemodynamic and electrocardiographic effects. Blood pressure, electrocardiographic measurements, cocaine plasma levels, temperature, electrolytes, and arterial blood gases were measured before and after the initial bolus and/or infusion at 10 minutes and each 30 minutes up to a maximum of 180 minutes. At the end of the infusion, a single large intravenous terminal bolus of cocaine was given. The hemodynamic and electrocardiographic changes occurred by 10 minutes after the bolus and resolved by 30 minutes, independent of the infusion rate and dose. Only anesthetized dogs could tolerate the highest cocaine doses. Three ranges of bolus doses were given: the lowest range was the average initial bolus dose received by the awake group; the intermediate range was the average initial bolus dose received by the anesthetized group; and the highest range was the average terminal bolus dose. The heart rate changes were unpredictable and did not change significantly at any dose range. The blood pressure increased in the lowest dose range, remained unchanged at intermediate doses, and fell at the highest doses in four of six dogs. Electrocardiographic intervals increased as the dose range increased. Only at the highest doses did potentially lethal ventricular arrhythmia (ventricular tachycardia and an idioventricular escape rhythm) occur. Intravenous cocaine causes hemodynamic and electrocardiographic effects that are related to the dose and rate of administration. At high doses, hypotension, arrhythmia, and electrocardiographic changes consistent with infranodal and/or intraventricular conduction slowing can occur.

Anesthesia, General↗
PubMed1989

Application of a novel immunization protocol to the production of monoclonal antibodies specific for macrophages in human placenta.

A monolayer depletion/adoptive immunization protocol that biased the immune response towards recognition of placental macrophage (pMO) antigens was established. BALB/c spleen cells immune to human pMO were adsorbed onto monolayers of the B-cell line QIMR-WIL. Monolayer-depleted or unfractionated cells were transferred to irradiated recipients, which subsequently were restimulated with pMO then killed for hybridoma production. Screening of hybridomas revealed an increased proportion of pMO-specific hybridomas following transfer and fusion of monolayer-depleted cells. Two monoclonal antibodies (mAb), L9 and L21, which were generated through application of this protocol, are described. L9 recognized an antigen on cells within the villi in sections of term placenta and freshly isolated pMO. With time in culture, expression of this antigen decreased markedly. Macrophages, but no other cell type, in placental cell suspensions expressed this antigen. L9 failed to react with any peripheral blood cells. Immunoprecipitation and SDS-PAGE analyses indicated that two proteins of molecular weight (MW) 40,000 and 43,000 were recognized by L9. Sections of term placenta and freshly isolated pMO failed to react with L21. After 2-3 days in culture, however, most macrophages expressed this antigen. L21 reacted weakly with peripheral monocytes and granulocytes but not other normal peripheral blood cells. Myeloid cell lines reacted strongly with this mAb only after activation with PMA. SDS-PAGE analyses of the L21 immunoprecipitate under non-reducing conditions revealed a single band of 61,000 MW, while two bands of 46,000 and 49,000 MW were detected under reducing conditions. Cellular distribution and molecular weight analyses indicated that the antigens recognized by these two mAb were apparently distinct from previously defined myeloid antigens.

Animals↗