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Biomedical subjects

R Sullivan

Publications and source records attributed to R Sullivan.

At least 109 records · Page 6Linked to original sources
PubMed1990

An experimental evaluation of interdisciplinary training in intervention with sexually abused adolescents.

Effective intervention in cases of sexual abuse of adolescents requires both knowledge of medical and other indicators and interviewing skills to facilitate disclosure. Public health settings are one place where the knowledge and skills of the health and social work professions can be effectively used to identify and protect adolescent victims. Interdisciplinary training was found to enhance requisite skills in this area. The experimental evaluation of a brief, state-wide, in-service training program found significant improvement in posttest knowledge of relevant indicators and interviewing skills and an increase in the number of cases identified and reported.

Adolescent↗
PubMed1990

Protein synthesis and acrosome reaction-inducing activity of human cumulus cells.

The acrosome reaction of human spermatozoa is a prerequisite to fertilization. It has been hypothesized that secretions of cumulus cells could be involved in the induction of this sperm reaction. A source of variation in the in-vitro fertilization of human oocytes could be the maturational differences in the cumulus cells which affect the acrosome reaction. In order to investigate this possibility, we have studied the capability of secretions obtained from cumulus cells of different maturational stages to induce the acrosome reaction. Capacitated spermatozoa were exposed to the culture medium containing cumulus cell secretions and their acrosomal status was evaluated using the triple stain technique. The maturational status of the cumulus or fertilization of the enclosed oocyte did not influence the percentage of acrosome-reacted live spermatozoa. In order to further document these observations, cumulus cells were submitted to [35S]methionine incorporation and total and secreted proteins were analysed by SDS-PAGE electrophoresis. Neither quantitative nor qualitative changes were detected in the electrophoretic patterns of the proteins obtained from cumulus cells of different maturational status. Thus, variation of the acrosome reaction-inducing activity of cumulus cells does not appear to be involved in the variable fertilization of oocytes obtained from follicles of differing maturity.

Acrosome↗
PubMed1989

Immunodetectable galactosyltransferase is associated only with human spermatozoa of high buoyant density.

Human ejaculated spermatozoa are heterogeneous and can be separated into two distinct populations according to their respective buoyant densities. In order to investigate the functional differences between these two types of spermatozoa, we have searched for the presence of galactosyltransferase. A Western blot of sperm proteins following their electrophoresis was probed with an anti-galactosyltransferase serum revealing that this enzyme is present in human spermatozoa. Furthermore, galactosyltransferase is detectable only in those proteins isolated from the head of high density spermatozoa. These results suggest that ejaculated spermatozoa consist of two populations that are functionally different.

Animals↗
PubMed1989

An elevation in the concentration of free cytosolic calcium is sufficient to activate the oxidative burst of granulocytes primed with recombinant human granulocyte-macrophage colony-stimulating factor.

In granulocytes harvested from human blood, an elevation of the cytosolic concentration of Ca2+ ions is by itself insufficient to activate the cell's respiratory burst. We report herein that, when granulocytes are "primed" by a 90-min preincubation with the recombinant human hemopoietic growth factor granulocyte-macrophage colony-stimulating factor (GM-CSFrh), elevation of the concentration of cytosolic Ca2+ ions ([Ca2+]i) becomes a more effective transduction signal capable of triggering the generation of substantial quantities of superoxide (O2-) anions by the cell. In these studies, we used four separate and independent maneuvers to induce elevation of [Ca2+]i: 1) depolarization of the cell's electrical potential through obliteration of the transmembrane Na+ and K+ gradients; 2) acidification of the cytoplasm using propionic acid; 3) addition of the calcium ionophore ionomycin; and 4) treatment of the cells with the monoclonal antibody to the C3bi receptor, PMN7C3. In all cases, elevation of [Ca2+]i through these manipulations resulted in the release of substantially greater quantities of O2- by GM-CSFrh-primed granulocytes than by unprimed, control cells. The generation of O2- was in all cases markedly reduced by chelation of either intracellular Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid or extracellular Ca2+ with [ethylene-bis(oxyethylenenitrilo)]tetraacetic acid. We conclude that during the process of GM-CSFrh priming, the metabolic assembly responsible for O2- anion production in the granulocyte becomes altered in such a way that a subsequent elevation in [Ca2+]i provides a potent signal for its activation.

Antibodies, Monoclonal↗
PubMed1989

Binding and activation of plasminogen on immobilized immunoglobulin G. Identification of the plasmin-derived Fab as the plasminogen-binding fragment.

We have found that tissue plasminogen activator catalyzes the binding of plasminogen (Pg) to immunoglobulin G (IgG) immobilized on a surface. This enhancement is due to the formation of plasmin, since plasmin treatment of immobilized IgG produced a 20-fold increase in Pg binding. Pg binding is lysine site dependent and reversible. The augmentation of Pg binding by plasmin is specific as other proteases produced significantly less or no effect. Immobilized plasmin-treated IgG also specifically binds Pg in plasma. IgG-immobilized Pg is activated by tissue plasminogen activator, and a significant portion of the plasmin formed remains bound to the IgG. The Pg reactive species in a plasmin-treated IgG digest was identified as the Fab fragment by chromatography utilizing the immobilized high affinity lysine-binding site of plasminogen. Specificity of the interaction was further demonstrated by immunoblot-ligand analysis which demonstrated that the plasmin-derived Fab fragment bound Pg whereas papain-derived Fab or plasmin-derived Fc fragments did not. These data suggest that Pg binds to the new COOH-terminal lysine residue of the plasmin-derived Fab. Pg also binds to an immobilized immune complex following plasmin treatment. These findings indicate that surface-bound IgG localizes plasminogen thus extending the spectrum of activity of the plasmin system to immunologic reactions.

Enzyme Activation↗
PubMed1989

Effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh) on transmembrane electrical potentials in granulocytes: relationship between enhancement of ligand-mediated depolarization and augmentation of superoxide anion (O2-) production.

When human granulocytes that have been primed with recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh) are activated by ligands that stimulate the respiratory burst, the amount of superoxide anion (O2-) they generate is significantly increased. We have found that the accelerated rate of O2- release occurring under these conditions is accompanied by an antecedent increase in membrane depolarization. We examined the nature of the enhancement of membrane depolarization in GM-CSFrh-primed granulocytes and investigated its relationship to the increase in O2- generation by N-formyl methionylleucylphenylalanine (fMLP)-activated granulocytes. We found that augmented depolarization could not be accounted for by a change in the resting membrane potential induced by the growth factor and was still present after either blocking passive transmembrane Na+ movement with dimethylamiloride or by increasing the membrane's permeability to K+ with valinomycin. When their ability to depolarize was virtually eliminated by dissipating the transmembrane K+ gradient, GM-CSFrh-pretreated cells continued to generate more O2- after fMLP than did control cells. These results indicate that augmentation of the granulocyte's ability to generate O2- anions, which is induced by priming with GM-CSFrh, is independent both of the resting transmembrane potential and of alterations in the extent of membrane potential change induced by stimuli such as fMLP.

Colony-Stimulating Factors↗
PubMed1989

Qualitative changes in protein synthesis associated with polyspermic fertilization of human eggs.

To investigate the early molecular events in human oocytes that are triggered by fertilization, the authors examined the pattern of polypeptides synthesized by unfertilized and dispermic embryos obtained through an in vitro fertilization and embryo transfer (IVF-ET) program. Compared with unfertilized oocytes of the same postovulatory age, the de novo protein synthesis in tripronuclear dispermic zygotes (21 hours postinsemination) was characterized by the appearance of three novel protein bands with molecular weights of 41.2, 35.3, and 26.0 kD. Concomitant with these changes, these zygotes showed the disappearance of bands at 54.0, 36.5, and 28.0 kD, along with the decreased synthesis of a protein band at 42.5 kD. Although 24% of the aged unfertilized oocytes exhibited bands corresponding to 41.2 and 35.3 kD, the 26.0 kD protein is restricted to the tripronuclear embryos. The significance of these results is discussed in relation to the use of polyspermic human oocytes as a model for the study of the early molecular events triggered by fertilization.

Densitometry↗
PubMed1989

Heterogeneity of epididymal spermatozoa of the hamster.

Epididymal transit is involved in the acquisition of fertilizing ability by mammalian spermatozoa. The epididymis is implicated in the addition and/or modification of sperm surface proteins functionally involved in the processes leading to fertilization. In order to characterize these sperm components, we have studied the modifications of sperm membrane proteins during epididymal maturation. Hamster spermatozoa were collected from the caput, corpus, and proximal and distal cauda of the epididymis and submitted to a continuous Percoll gradient centrifugation. Independently of their epididymal origin, the spermatozoa were distributed into two bands of buoyant densities of 1,045 and 1,088 on the gradient. However, the proportion of more dense spermatozoa increased progressively along the epididymis. This proportion is 87-fold higher in the distal cauda compared to the caput. SDS-PAGE electrophoresis demonstrated that although they originate from different regions of the epididymis, spermatozoa of the same density exhibited similar membrane protein patterns. In contrast, the electrophoretic patterns of spermatozoa with densities of 1,045 and 1,088 were very different. One of these differences involves a 26 kD protein that is implicated in zona pellucida recognition (Sullivan and Bleau, Gamete Res 12:101-116, 1985). This protein is present in dense sperm obtained from all regions of the epididymis but is absent in spermatozoa of low density. If we consider that this 26 kD protein is a "marker" of surface changes occurring during sperm maturation, we can hypothesize that in the proximal segments of the epididymis a certain proportion of spermatozoa are indeed mature but that this proportion increases considerably along the epididymis.

Animals↗
PubMed1989

Haemophilus influenzae b polysaccharide revaccination: a continued role for the unconjugated vaccine.

In a study of the issue of revaccination with Haemophilus influenzae b polysaccharide vaccine, 36 children who had been vaccinated with polysaccharide vaccine at age 18 to 20 months were stratified according to their 3-week postvaccination anticapsular antibody concentration determined by radioantigen binding assay, then sequentially assigned to one of three groups so as to have comparable distributions of peak antibody concentrations. These children were revaccinated with polysaccharide vaccine at 24 to 27, 30 to 33, or 36 to 39 months of age. The post-reimmunization geometric mean antibody concentrations in these three groups were 3.1, 3.0 and 7.8 micrograms/ml, respectively, and the percentages rising to greater than 1 microgram/ml were 75, 80 and 93%. The geometric means and antibody response rates were nearly identical to age-matched control groups not previously vaccinated. Thus there was no evidence of priming (memory induction) or of tolerance induction by the early (18 months old) primary vaccination.

Age Factors↗
PubMed1989

Enhancement of superoxide anion release by granulocytes harvested from patients receiving granulocyte-macrophage colony-stimulating factor.

We examined the rate and quantity of superoxide anion (O2-) generation by granulocytes harvested from the blood of patients before and after a 12-24 h constant intravenous infusion with recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh). Seven previously untreated patients with sarcomas who exhibited no bone marrow involvement by their disease were studied. Granulocytes were harvested from the peripheral blood of each patient before and after intravenous infusion with GM-CSFrh. The total quantity of O2- produced and the kinetics of its release were then determined following in vitro activation of the cells by the chemotactic peptide N-formyl methionyl-leucylphenylalanine (fMLP) or by phorbol myristate acetate (PMA). In all cases, the amount of O2- generated and the rate of its release were significantly increased after GM-CSFrh infusion. Our findings indicate that intravenous administration of GM-CSFrh to patients heightens the functional responsiveness of circulating granulocytes.

Adult↗
PubMed1989

Triage: a subspecialty of emergency nursing.

Triage nursing is evolving as a subspeciality of emergency nursing. Of the five major types of triage systems in use, four utilize nursing personnel. The Advanced Triage System is the most comprehensive system and is utilized in the Emergency Department at Harbor-UCLA Medical Center. This article defines the process of triage, reviews various types of triage systems and discusses the role of the triage nurse in the Advanced Triage System utilized at Harbor-UCLA Medical Center.

Emergencies↗
PubMed1988

Clostridium difficile toxin A stimulates intracellular calcium release and chemotactic response in human granulocytes.

Clostridium difficile, a common enteric pathogen, mediates tissue damage and intestinal fluid secretion by release of two protein exotoxins: toxin A, an enterotoxin, and toxin B, a cytotoxin. Because toxin A elicits an intense inflammatory reaction in vivo, we studied the effects of highly purified C. difficile toxins on activation of human granulocytes. Toxin A at concentrations of 10(-7) to 10(-6) M, but not toxin B, elicited a significant chemotactic and chemokinetic response by granulocytes that was comparable with that induced by the chemotactic factor N-FMLP (10(-7) M). Neither toxin stimulated release of superoxide anion from granulocytes. Toxin A produced a rapid, transient rise in cytosolic [Ca2+]i, as measured by quin 2 fluorescence. Pertussis toxin and depletion of intra- and extracellular calcium blocked the toxin A effect on cytosolic [Ca2+]i. These findings suggest that the inflammatory effects of C. difficile toxin A in the intestine may be related to its ability to mobilize intracellular Ca2+ and elicit a chemotactic response by granulocytes.

Bacterial Toxins↗
PubMed1988

Prevention of lower extremity stress fractures: a controlled trial of a shock absorbent insole.

A prospective controlled trial was carried out to determine the usefulness of a viscoelastic polymer insole in prevention of stress fractures and stress reactions of the lower extremities. The subjects were 3,025 US Marine recruits who were followed for 12 weeks of training at Parris Island, South Carolina. Polymer and standard mesh insoles were systematically distributed in boots that were issued to members of odd and even numbered platoons. The most important finding was that an elastic polymer insole with good shock absorbency properties did not prevent stress reactions of bone during a 12-week period of vigorous physical training. To control for the confounding effects of running in running shoes, which occurred for about one and one-half hours per week for the first five weeks, we also examined the association of age of shoes and cost of shoes with injury incidence. A slight trend of increasing stress injuries by increasing age of shoes was observed. However, this trend did not account for the similarity of rates in the two insole groups. In addition, we observed a strong trend of decreasing stress injury rate by history of increasing physical activity, as well as a higher stress injury rate in White compared to Black recruits. The results of the trial were not altered after controlling for these factors. This prospective study confirms previous clinical reports of the association of stress fractures with physical activity history. The clinical application of a shock absorbing insole as a preventive for lower extremity stress reactions is not supported in these uniformly trained recruits. The findings are relevant to civilian populations.

Adolescent↗
PubMed1988

Effects of recombinant human granulocyte-macrophage colony-stimulating factor on intracellular pH in mature granulocytes.

We studied the effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh) on the internal pH of granulocytes using the fluorescent probe BCECF. GM-CSFrh did not directly alter the resting pH of granulocytes isolated from the peripheral blood; however, when the cells were preincubated for 90 minutes with the growth factor and then activated with the chemotactic peptide N-formyl met leu phe (fMLP), they exhibited both an acceleration in the initial rate of acidification and a marked delay in realkalinization. The kinetic changes both in initial acidification and in subsequent realkalinization induced by GM-CSFrh priming were not prevented by protein synthesis inhibitors and were observed in granulocytes harvested from patients with both sex-linked and autosomal recessive chronic granulomatous disease (CGD). By directly quantitating H+ ion secretion, by monitoring the effects of sodium repletion on intracellular pH, and through use of the sodium channel inhibitors amiloride and dimethyl amiloride and the Na+/K+-ATPase inhibitor ouabain, we showed that the altered kinetics of intracellular acidification and alkalinization following fMLP stimulation of GM-CSFrh-primed granulocytes could not be accounted for by changes in transmembrane proton exportation regulated by the Na+/H+ antiport channel. Although the initial acidification following fMLP was abrogated by 2-deoxy-D-glucose in both GM-CSFrh-pretreated and GM-CSFrh-untreated granulocytes, retardation of the subsequent phase of alkalinization was observed in GM-CSFrh-primed cells even after inhibition of both glycolytic and mitochondrial metabolism. Our data indicate that the increased cytosolic acidification following fMLP stimulation in granulocytes "primed" with GM-CSFrh does not result from disordered proton excretion but instead from increased release of intracellular free acid which is only partially coupled to glucose catabolism or to the generation of superoxide anion (O2-).

Amiloride↗
PubMed1988

Granulocyte-macrophage colony-stimulating factor induces the expression of the CD11b surface adhesion molecule on human granulocytes in vivo.

The CD11b (Mol) molecule is a member of a family of surface glycoproteins that are essential for adhesion-dependent granulocyte functions. Brief exposure of granulocytes to human granulocyte-macrophage colony-stimulating factor (GM-CSF) in vitro increases the surface expression of CD11b and increases granulocyte adhesiveness. To assess the possible in vivo significance of these observations we studied the effect of GM-CSF on CD11b, CD11a (LFA-1), and CD11c (gp 150, 95) expression on granulocytes from nine adult patients with sarcoma who were receiving GM-CSF as part of a phase I trial. GM-CSF was administered as a continuous infusion at a dose of 32 or 64 micrograms/kg/d. Granulocyte CD11b, CD11a, and CD11c expression was determined by indirect immunofluorescence staining of whole blood, thereby minimizing in vitro manipulation. A transient leukopenia developed within 15 minutes of initiation of GM-CSF treatment that was associated with a marked increase in the surface antigen density of CD11b. A mean 1.7-fold increase (P = .001) in the percentage of CD11b-positive granulocytes and a mean 2.1-fold increase (P = .002) in CD11b surface antigen density was noted after 12 hours of treatment. No change in CD11a or CD11c expression was observed over the first 12 hours. The level of CD11b expression was followed in six patients for up to 5 days of treatment with GM-CSF. Compared with the 12-hour value, three of six patients showed a subsequent decrease in CD11b expression, two remained constant, and one showed a continued increase in CD11b surface density. Fluorescence-activated cell sorting of granulocytes into high- and low-density CD11b-positive groups revealed a preponderance of immature myeloid forms in the low-density CD11b fraction, which suggests that the late decrease in CD11b expression in some patients may be related to a greater proportion of circulating immature myeloid forms in the peripheral blood. This study suggests that GM-CSF administered as a continuous infusion rapidly upregulates the expression of granulocyte CD11b in vivo. The influence of this phenomenon on in vivo granulocyte aggregation may be clinically relevant with regard to the toxicity of GM-CSF and deserves further investigation.

Antigens, Differentiation↗
PubMed1988

Distribution of the 124-kd antigen defined by monoclonal antibody AML-1-99 on normal and leukemic myeloid cells.

We have produced a monoclonal antibody (MoAb), AML-1-99, that defines a novel 124-kd protein antigen expressed on a subpopulation of monocytes and on the majority of hematopoietic progenitor cells of the granulocyte-monocyte (CFU-GM), erythroid, and mixed-lineage classes. AML-1-99 is lytic to bone marrow (BM)- and peripheral blood-derived progenitor cells in the presence of rabbit complement (C'). AML-1-99 is not toxic to progenitor cells in the absence of C', nor does it modify their growth when included in colony-forming cultures. Several leukemia cell lines, including HL-60, U937, KG-1a, and Daudi cells, express the antigen on the majority of cells. Freshly isolated leukemia cells from patients with acute myelogenous leukemia (AML) react variably with AML-1-99. Leukemia colony-forming cells from several AML patients express the antigen and could be eliminated by treatment with AML-1-99 and C'. Cell sorting and immune rosette techniques were successfully applied to normal BM and chronic myelocytic leukemia cell populations using AML-1-99 with the result that significant enrichment of CFU-GM could be accomplished. The pattern of reactivity of this MoAb and its apparent molecular weight suggests that AML-1-99 recognizes a newly defined myeloid-associated cell surface antigen.

Antibodies, Monoclonal↗