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Biomedical subjects

D M Smith

Publications and source records attributed to D M Smith.

At least 271 records · Page 15Linked to original sources
PubMed1989

Characterization of sites of serine phosphorylation in human placental insulin receptor copurified with insulin-stimulated serine kinase activity by two-dimensional thin-layer peptide mapping.

Insulin receptor was copurified from human placenta together with insulin-stimulated kinase activity that phosphorylates the insulin receptor on serine residues. Analysis of phosphorylated insulin receptor by two-dimensional tryptic peptide mapping showed that sites of insulin stimulated serine phosphorylation in the insulin receptor were recovered in the same peptides as those known to be phosphorylated on serine in vivo in response to insulin. This indicates that the serine kinase copurified with the insulin receptor represents a physiologically important enzyme involved in the insulin triggered serine phosphorylation of the insulin receptor in vivo.

Humans↗
PubMed1989

Functional and metabolic heterogeneity among normal neutrophil subpopulations.

In this study, normal human peripheral blood neutrophils were separated into subpopulations by centrifugation on discontinuous Percoll density gradients and further characterized according to various functional and metabolic capabilities. Chemotaxis was measured in response to optimal concentrations (20 nM) of the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP). According to a population ratio analysis, the majority of cells that contain the highest proportion of fast migrating cells are isolated between the densities of 1.093 and 1.096 gm/ml. Arachidonic acid (AA) metabolism was also determined in neutrophil subpopulations. On initial density gradients, cells isolated from 1.084-1.087 gm/ml and incubated in the presence of exogenous [3H]AA produce 50% of the total [3H]LTB4 produced in response to ionophore A23187 stimulation; whereas after prelabeling with [3H]AA for 2 hr at 37 degrees C, the cells between 1.087 and 1.093 gm/ml are the most active at both releasing [3H]AA from the cellular phospholipids and synthesizing [3H]LTB4 (dpm/cell). These studies demonstrate the significant functional and metabolic heterogeneity that exists among normal neutrophil subpopulations.

Arachidonic Acid↗
PubMed1989

Removal of peripheral blood monocytes by phenylalanine methyl ester has no effect on the colony growth of hematopoietic progenitor cells.

Purification of hematopoietic cells often includes an adherence step for the removal of monocytes. Recent studies have shown that some hematopoietic cells are adherent and that plastic adhesion might activate monocyte/macrophage for cytokine production. We investigated the possibility of using L-phenylalanine methyl ester (PME) as an alternative approach to monocyte removal, particularly for large-scale cell separations. Cell yield, extent of monocyte removal and cloning efficiency of colony-forming progenitor cells were compared to that produced by plastic adhesion. Starting with mononuclear cells (MNC) from adult peripheral blood, cell recovery after PME treatment was higher than that achieved with adherence and fewer monocytes were present. Cloning efficiency of the granulocyte-monocyte colony-forming progenitor cells (CFU-gm) was not affected by the PME treatment. PME treatment and plastic adhesion of low-density cord blood cells produced comparable cell recovery, monocyte depletion and cloning efficiencies for CFU-gm and burst forming units for erythroid progenitor cells (BFU-e). The PME procedure was optimized for the purification of hematopoietic cells from large quantities (less than 1 x 10(9)) of low density. T cell-depleted peripheral blood MNC containing 60% to 85% monocytes. Compared to two cycles of plastic adhesion, PME treatment permitted higher cell recovery (5.9% vs. 1.3%), lower monocyte contamination (4.5% vs. 10.7%) and substantial cost, time and labor savings without compromising CFU-gm growth.

Cell Adhesion↗
PubMed1989

The effect of clomiphene citrate on human preovulatory oocyte maturation in vivo.

Sixty-four infertile women underwent diagnostic laparoscopy in the periovulatory period at time-bracketed intervals following their endogenous luteinizing hormone (LH) surge. Forty-eight of these women were studied during natural cycles and 16 had mild oligoovulation and were administered clomiphene citrate (CC) to regulate their cycles. No patient received human chorionic gonadotropin. No patient was undergoing either in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT). Follicle puncture was performed and the oocytes were observed immediately for stage of maturation. Oocytes obtained from follicles exposed to CC were found to require an increased interval of time to reach metaphase I compared to oocytes obtained from natural cycles (27.75 +/- 2.2 vs 22.5 hr; mean +/- SE). Furthermore, the interval of time required for metaphase I oocytes to achieve metaphase II was statistically significantly shortened for CC cycles (2.4 hr for CC vs 10 hr for natural cycles. Nevertheless, there was no difference between natural and CC cycles in the time interval between LH surge onset and ovulation. These in vivo findings suggest a direct effect of CC on human oocyte maturation and may help explain the well-established discrepancy between the relatively high ovulation rate and the relatively low conception rate in clomiphene-induced cycles.

Clomiphene↗
PubMed1989

Biochemical characterization of soluble phospholipase A2 from rheumatoid synovial fluid.

Radiolabeled E. coli, Phosphatidylethanolamine (PE) and Phosphatidylcholine (PC), were used to characterize the phospholipase A2 (PLA2) activity in synovial fluid (SF) from rheumatoid arthritis (RA) patients. Cell-free fractions of SF contain a PLA2 enzyme that preferentially releases [14C]oleic acid from E. coli, requires calcium and is optimally active at neutral pH. Purified PE, but not PC is also readily degraded by the soluble enzyme. A cell-associated PLA2 present in sonicates of SF mononuclear cells and neutrophils preferentially releases [3H]AA from E. coli. These studies suggest the presence of at least two different enzymes with activity of PLA2 in rheumatoid SF.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Determination of cellular oncogene rearrangement or amplification in ovarian adenocarcinomas.

Four cellular oncogenes, fos, myc, Ha-ras, and Ki-ras, are routinely expressed in ovarian adenocarcinomas. To determine whether the molecular lesion in ovarian carcinoma was a genetic rearrangement or amplification of expressed oncogenes, we examined the myc, Ha-ras, Ki-ras, and fos oncogenes in 14 serous adenocarcinomas of the ovary using molecular hybridization techniques. Using a series of diagnostic restriction endonucleases and gene-specific deoxyribonucleic acid probes, we found no evidence of rearrangement of these genes. In addition, we found no evidence of amplification of the cellular oncogenes analyzed in this series of ovarian tumors. Therefore genetic rearrangement or amplification of these cellular oncogenes is not the primary molecular lesion leading to their expression in ovarian carcinomas.

Adenocarcinoma↗
PubMed1989

Cellular stimuli for rejection of sarcoma I tumor allografts by BALB/c recipient mice.

We have evaluated the role of passenger leukocytes in Sarcoma I (SaI) tumor allograft rejection by BALB/c recipient mice. SaI tumor cells grown in tissue culture expressed low levels of class I MHC antigens as determined by flow cytometry. Ascites-derived tumor cells contained additional cell populations of A/J host origin which expressed high levels of class I and class II alloantigens. Tissue culture-derived SaI grafts grew progressively or were rejected in delayed fashion by some BALB/c hosts. In contrast, ascites-derived tumor allografts were rejected rapidly by 100% of recipient mice. Passenger cells appear to be responsible for these striking differences in immunogenicity because the addition of allogeneic A/J splenocytes to the tissue culture form of SaI caused rapid rejection. When tissue culture- and ascites-derived tumors simultaneously were grafted on opposite shoulders of recipient mice, both tumors were rejected. These data indicate that passenger cells provide the primary stimulus for SaI tumor allograft rejection by BALB/c mice. The mechanism of SaI enhancement by anti-Ia antibodies may be analogous to the prolonged survival of endocrine grafts after depletion of Ia+ passenger leukocytes.

Animals↗
PubMed1989

QUAD: a computer package for the analysis of QUantal Assay Data.

The computer package QUAD has been developed at the University of Kent, U.K. It is menu driven and written in Advanced BASIC. It runs on IBM PC compatible machines equipped with a suitable graphics facility such as CGA or simulated CGA. QUAD is available on a floppy disk, for a small handling charge. QUAD has four main functions: it performs a logit analysis of quantal assay data; it provides a flexible way of analysing the data, allowing dose transformations and providing alternative confidence intervals for EDp values; it produces a range of diagnostics for assessing the fit of models to data; it provides and fits two families of extended models, each containing the logit as a special case. The package makes use of the latest statistical research, and fitted models are displayed by means of the good graphics facilities available on microcomputers. This document describes the facilities available in detail, and provides and discusses, illustrations of the package at work. QUAD has been designed as a pilot package. Further additions and developments are planned and described later.

Animals↗
PubMed1989

Phospholipid metabolism in polymorphonuclear leukocytes from rheumatoid arthritis patients: effects of non-steroidal anti-inflammatory agents and clotrimazole.

Arachidonic acid (AA) metabolism and phospholipase A2 (PLA2) activity were measured in the peripheral blood polymorphonuclear leukocytes (PMNL) from ten patients with rheumatoid arthritis (RA) on treatment with various non-steroidal anti-inflammatory agents (NSAIA). AA metabolism and PLA2 activity were measured both initially and after treatment with either placebo or Clotrimazole, a broad spectrum anti-mycotic agent, as a possible anti-rheumatic drug. AA metabolism was also measured in PMNL from ten patients with active RA untreated with any NSAIA and ten normal volunteers. Using 3H-AA prelabeled cells, we show that there was a significantly higher (P less than 0.025) production of 3H-LTB4 in response to stimulation with the calcium ionophore A23187 in untreated RA patients than in normal volunteers (mean +/- S.D.:4.8 +/- 1.6% and 3.1 +/- 1.0%, respectively). The production of 3H-LTB4 by PMNL from patients on NSAIAs was less elevated (mean +/- S.D.:4.1 +/- 1.5%) and was not significantly different from normal controls. Concurrently we examined PLA2 activity in PMNL-sonicates from ten of our study patients using autoclaved [14C]oleate-labeled E. coli biomembranes as an exogenous substrate. Using linear regression analysis, we demonstrate a significant correlation between in vitro PLA2 activity and the release of 3H-AA from the cellular phospholipids (deacylation) in response to A23187 stimulation (r = -0.526, P less than 0.025). We also demonstrate significant correlations between the overall clinical state of the RA patient, as evaluated by a modified rheumatoid activity index (MRAI), and both the release of 3H-AA from the cellular phospholipids and its production of total [3H]eicosanoids (r = -0.557, P less than 0.025 and r = 0.644, P less than 0.005, respectively). This data suggests that: PLA2 activity may, in part, account for the higher generation of LTB4 by RA PMNL; NSAIAs may be capable of modulating this abnormality; and Clotrimazole may affect the clinical or laboratory data of RA patients already on treatment with NSAIA.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Genetic and immunopathological findings in a lymphoma family.

We have studied a remarkable family with seven cases of malignant lymphoma extending through three generations wherein five sisters and their mother had histopathologically documented non-Hodgkin's lymphoma, while a granddaughter had Hodgkin's disease. An immunological study of three lymphoma survivors, nine of their first degree relatives, and four spouse controls was undertaken. Significant findings consisted of a depressed serum IgG3 level in four of the nine first-degree relatives; in two of these four, lymphocyte stimulation by both pokeweed mitogen and concanavalin A were significantly depressed. The subtle immunological abnormalities present in this kindred may be associated with the pathogenesis of the lymphomas.

Adult↗
PubMed1989

Organizational socialization of physical therapists.

Organizational socialization is the process by which an individual becomes a member of an organization. It involves interaction between the employee and the organization during recruitment, hiring, and training and continues as the employee's role in the organization is defined and develops. The individual and the employee each have a set of expectations for the other; the extent to which these expectations are recognized, communicated, and combined in a mutually agreeable "psychological contract" can influence the eventual effectiveness, satisfaction, and longevity of the individual as an employee. The purpose of this article is to describe organizational socialization as it applies to the physical therapy setting. The author makes recommendations for management of the process.

Employee Performance Appraisal↗
PubMed1989

Hearing aids worn with tympanic membrane perforation: complications and solutions.

Hearing aids are sometimes recommended in ears with tympanic membrane perforation. Presented are six illustrative cases that represent various degrees of perforation, ear-mold styles, and wearing habits. The degrees of perforation represented include total, 50%, 20%, myringotomy tube, and modified mastoid cavity (canal up). Patients wearing earmolds with total perforation experience nearly constant irritation, infection, itching, or drainage. Rare periods of success are achieved in such cases by strict adherence to hygiene and ventilation guidelines. Lesser degrees of perforation usually experience significantly fewer problems if such guidelines are followed. Ear ventilation is found to be the primary success factor, whether achieved by periods of non-use or earmold venting. Since the potential for serious complications always exists, such fittings require patient education and regular otologic follow-up.

Aged↗
PubMed1989

Characterisation of soluble and cell associated phospholipase A2 from rheumatoid synovial fluid.

The hydrolysis of radiolabelled Escherichia coli phospholipids, and micellar dispersions of phosphatidylethanolamine and phosphatidylcholine, were used to characterise the phospholipase A2 activity in synovial fluid from patients with rheumatoid arthritis. Cell free fractions of synovial fluid contain a phospholipase A2 enzyme that preferentially releases [14C]oleic acid from E coli biomembranes (specific activity 291.3 (SEM 27.6) pmol/min/mg). This enzyme requires calcium and is optimally active at neutral pH. Purified dispersions of phosphatidylethanolamine are also readily degraded by the soluble enzyme, but it is not active against phosphatidylcholine. The substitution of [14C]oleic acid by [3H]arachidonic acid for the labelling of E coli allowed differentiation between the soluble phospholipase A2 and the cell associated phospholipase A2 present in sonicates of mononuclear cells and neutrophils from peripheral blood and synovial fluid. The cell associated phospholipase A2 preferentially releases [3H]arachidonic acid from E coli cardiolipin. In this paper the phospholipid substrate specificity of phospholipase A2 from rheumatoid synovial fluid, the optimal assay conditions for its detection, and a standardised expression of activity in terms of pmol per minute per mg of protein are established.

Arthritis, Rheumatoid↗
PubMed1989

Extreme endurance training and fiber type adaptation in rat diaphragm.

Extreme endurance training was used to investigate the adaptability of the rat diaphragm muscle fibers. During the final phase of the 14-wk training program, the animals were running for 240 min/day at an estimated requirement of 80% of pretraining maximal O2 consumption. Analysis of a sample of the costal diaphragm indicated that training resulted in a 34% reduction (P less than 0.05) in the percent distribution of type IIa fibers [27.7 +/- 1.1 vs. 18.3 +/- 2.6 (SE)] and a 15% increase (P less than 0.05) in the percent of type IIb fibers (40.0 +/- 1.2 vs. 46.1 +/- 2.4). No change (P greater than 0.05) was found in the distribution of the type I fibers (32.3 +/- 1.2 vs. 35.7 +/- 1.3). Oxidative potential as assessed with NADH-tetrazolium reductase and measured microphotometrically increased (P less than 0.05) by 19% in type I fibers but did not change in either the type IIa or type IIb fibers. No effect of training was found when a different oxidative marker, succinic dehydrogenase, was employed. Similarly glycolytic potential based on the activity of alpha-glycerophosphate dehydrogenase was not affected by training. Glycogen concentration was elevated by 60% (P less than 0.01) in type I fibers and 77% (P less than 0.01) in type IIb fibers with training but was not altered (P greater than 0.05) in type IIa fibers. Reductions (P less than 0.05) in fiber area ranging from 11 to 20% were observed in all fiber types as a result of training, whereas the number of capillaries per fiber remained static.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Recombinant TGF-beta 1 is synthesized as a two-component latent complex that shares some structural features with the native platelet latent TGF-beta 1 complex.

The entire coding region of the human transforming growth factor beta 1 (TGF-beta 1) precursor cDNA has been stably expressed in a human renal carcinoma cell line. Like platelet TGF-beta 1, the recombinant TGF-beta 1 is secreted in a biologically latent form. Immunoblot analysis and gel-filtration indicate that the recombinant latent TGF-beta 1 is a 100-kDa complex in which active 25-kDa TGF-beta 1 is noncovalently associated with the remaining 75 kDa of the processed precursor. Unlike the platelet latent complex, the recombinant latent complex contains no 135-kDa component. Thus, the processed precursor peptide alone is sufficient to confer latency on active TGF-beta 1, and the 135-kDa platelet component has a different role. The processed precursor is similarly glycosylated in recombinant and platelet complexes, and in both has an exposed heparin binding site that may be involved in targeting of the latent complex. Finally, acid activation of recombinant and platelet complexes is reversible, suggesting that the activation process does not cause major structural modifications in the components of the latent complex.

Binding Sites↗
PubMed1989

High-dose therapy and autologous peripheral blood stem cell transplantation for patients with lymphoma.

Forty patients with refractory Hodgkin's disease (24 patients) or non-Hodgkin's lymphoma (16 patients) who were considered for high-dose therapy but not for autologous bone marrow transplantation (ABMT) due to BM metastases, previous pelvic irradiation, a history of marrow involvement by tumor or hypocellular marrow in conventional harvest sites received high-dose therapy and autologous peripheral blood (PB) hematopoietic stem cell transplantation. Disappearance of circulating neutrophils and development of RBC and platelet transfusion-dependence was followed, in the evaluable patients, by reappearance of 0.5 x 10(9)/L circulating granulocytes and sufficient platelets to obviate the need for platelet transfusions at a median of 25 days after transplantation. Twenty-three patients experienced a clinical complete remission (CR). The projected 2-year event-free survival was 24% for all 40 patients and 49% for the non-Hodgkin's lymphoma patients. The projected 18-month event-free survival for the Hodgkin's disease patients was 15%. PB stem cell transplantation provided an opportunity to administer high-dose salvage therapy to patients with refractory lymphoma who otherwise were not candidates for such therapy. For some of those patients, the high-dose therapy produced prolonged survival, free of tumor progression.

Actuarial Analysis↗