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Biomedical subjects

D A McCarthy

Publications and source records attributed to D A McCarthy.

At least 37 records · Page 2Linked to original sources
PubMed1994

The ex vivo function and expression of function-associated antigens of peripheral blood neutrophils and monocytes.

The availability of recombinant human granulocyte and granulocyte-macrophage colony-stimulating factors (rhG-CSF and rhGM-CSF) has prompted many studies of the analysis of antigen expression and function of monocytes and neutrophils from patients receiving these factors as therapeutic agents. Preparatory procedures for leukocytes are known to alter antigen expression and so function. We therefore investigated the use of a novel procedure in which live leukocytes are analyzed by flow cytometry without isolation from blood. The expression levels of CD11b, CD13, CD14, CD16, and CD18 antigens and L-selectin (TQ1 and Leu-8 epitopes) on neutrophils and monocytes from 15 normal individuals were determined and compared with a previously used method in which the leukocytes were fixed and the erythrocytes lysed before analysis. Significant differences for the apparent expression of CD11b, CD18, and L-selectin were observed between the two methods. The reasons for this were investigated. Since the new method allowed analysis of live cells, we also investigated whether modulation of antigen expression could be determined following receptor agonist interaction. This was found to be easily achievable, and we advocate using the new procedure where possible for the ex vivo analysis of function and function-associated antigens on monocytes and neutrophils.

Adult↗
PubMed1994

An eclectic inpatient treatment model for Vietnam and Desert Storm veterans suffering from posttraumatic stress disorder.

This paper describes the therapeutic components of an eclectic, intensive inpatient treatment strategy for Vietnam and Desert Storm veterans with posttraumatic stress disorder. A specific treatment model was devised by this author. The procedure was a collaborative effort: the staff and the patients participated in this preparatory phase treatment program at the Tripler Posttraumatic Stress Unit, Tripler Army Medical Center, Honolulu, Hawaii. The basic treatment is based on group therapy, utilizing educational, cognitive-behavioral therapy, gestalt therapy, and individualized psychotherapy, and eye movement desensitization strategies. The timing and sequencing of these treatments are a critical part of the model, and we have come to refer to it as the layered model because the treatments are layered, much like the delicious parfait dessert.

Adaptation, Psychological↗
PubMed1993

A simple flow cytometric procedure for the determination of surface antigens on unfixed leucocytes in whole blood.

A novel procedure has been developed for the quantitation by flow cytometry of function-associated antigens on neutrophils and monocytes in unlysed, unfixed, peripheral blood samples. Freshly drawn blood anticoagulated with the serine esterase inhibitor, phenylmethylsulphonyl fluoride, is mixed with the vital nucleic acid stain, LDS-751, labelled with monoclonal antibodies for 5 min at 4 degrees C, diluted and analysed in a five-parameter flow cytometer. The three major leucocyte subpopulations (neutrophils, lymphocytes and monocytes) can be resolved in real time on the basis of their side light scattering and staining intensity with LDS-751 in the FL3 channel (erythrocytes and platelets stain very weakly), whilst the fluorescence intensity due to bound fluorescein isothiocyanate- or phycoerythrin-labelled antibody is monitored simultaneously in the FL1 or FL2 channels respectively. This procedure avoids potential artefacts that can occur due to the use of fixatives, erythrocyte lysing agents, or anticoagulants which are also divalent metal ion chelators. It should be widely applicable for the quantitation of those function-associated antigens, such as adhesion molecules and immune complex receptors, whose surface expression can be rapidly upregulated following activation, as well as for the quantitation of those leucocyte surface antigens whose expression is not subject to rapid modulation.

Antigens, Surface↗
PubMed1992

Studies on the immediate and delayed leucocytosis elicited by brief (30-min) strenuous exercise.

Eight healthy male volunteers exercised for two 30-min sessions starting 3 h apart on an electronically braked cycle ergometer at a work load (mean 155.9 W, SD 33.4 W) which required an oxygen consumption that was 70% of their maximal rate of oxygen uptake. Venous blood samples were taken through an indwelling cannula over a period of 6 h beginning shortly before the first bout of exercise and were analysed for routine haematological parameters and for lactate, noradrenaline, adrenaline and cortisol. Both bouts of exercise induced an immediate leucocytosis due to rises in lymphocytes and neutrophils but only the first exercise bout induced a substantial delayed neutrophilia. In at least five subjects, changes in lymphocyte and platelet numbers were correlated (Spearman's rank procedure, P less than 0.05) with simultaneous changes in the plasma concentrations of lactate, noradrenaline and adrenaline over the 6-h period studied. Increases in the plasma concentration of cortisol due to exercise correlated positively with the percentage changes in neutrophil numbers at 3 h and 6 h. These results are consistent with the suggestion that the immediate and delayed leucocytosis induced by exercise are mediated respectively by catecholamine and by cortisol.

Adult↗
PubMed1992

Changes in the leucocyte count during and after brief intense exercise.

Twelve healthy male volunteers exercised at 200 W on a cycle ergometer for 8 min or until exhausted, if sooner. Retrospectively, subjects fell into two groups. During the last minute of exercise at 200 W, those in group 1 (n = 5) had a mean respiratory exchange ratio (R) of 1.06 (SD 0.01) and were working at a mean of 79% (SD 4%) of their maximum oxygen consumption (VO2max) as measured in a separate incremental load test. For subjects in group 2 (n = 7), R was 1.31 (SD 0.08) and their VO2 was maximal (mean 101%. SD 3%). Plasma lactate, and adrenaline concentrations rose to higher levels during exercise in subjects in group 2 than in those in group 1. At the finish of exercise, the leucocyte count and the plasma lactate concentration immediately began to fall in subjects in group 1 whereas in group 2 subjects both rose for several minutes before falling. Plasma catecholamine concentrations fell rapidly in both groups during recovery.

Adult↗
PubMed1992

Coxsackievirus B4 infection of the mouse pancreas: acute and persistent infection.

The course of infection of a pancreas-adapted isolate of coxsackievirus B4 was followed over a 10 month period in a murine model. Following intraperitoneal inoculation a typical acute infection was seen in nine of 10 inbred mouse strains. Virus rapidly infected the exocrine pancreas, titres peaking 3 to 4 days post-infection (p.i.). Lesions were almost exclusively confined to pancreatic acinar cells and varied in severity among the inbred strains. Virus shed into the blood-stream was not cell-associated. Evidence of persistent infection was found in nine mouse strains and infective virus was recovered from the pancreas of seven strains for up to 10 months p.i. Approximately 28% of pancreases examined beyond the acute phase showed focal inflammation and 22% showed focal necrosis (cell death). Virus was occasionally recovered from other organs (heart, liver and spleen), but lesions were rarely seen. Virus-specific antigen was localized to small groups of pancreatic acinar cells using an indirect immunogold silver staining technique. These observations suggested that the virus persists in pancreatic tissues because it seems unlikely that virus disseminated from distant sites would cause such localized infection. In three of these strains, the course of infection may have been influenced by superinfection with mouse hepatitis virus.

Acute Disease↗
PubMed1992

Morphological evidence that activated polymorphs circulate in the peripheral blood of patients with rheumatoid arthritis.

Purified peripheral blood polymorphonuclear leucocytes (PMNs) from patients with rheumatoid arthritis (RA) have been found to differ from purified PMNs from normal subjects in ways that are consistent with their prior activation. However, it is currently contentious whether activated PMNs really circulate in patients with RA, or whether they are produced as an in vitro artefact of purification. Recently developed rapid leucocyte fixation and preparation technique showed that the proportion of polarised (activated) PMNs (36.9 (24.7)%, mean (SD); n = 31) was increased relative to that in control subjects (8.1 (5.6)%; n = 12). Serum cytidine deaminase levels, a biochemical marker of PMN lysis, were also increased in patients with RA (11.59 (7.26) U/ml) compared with those in controls (6.82 (3.78) U/ml), but the proportion of polarised PMNs and the levels of cytidine deaminase activity were unrelated to clinical assessments of inflammatory disease activity. Twelve patients who were not receiving drugs or who were receiving only non-steroidal anti-inflammatory drugs (NSAIDs) had more polarised PMNs than 19 patients receiving second line treatment in addition to NSAIDs (patients receiving NSAIDs, 49.6 (25.9)%; patients receiving second line treatment, 27.5 (21.1)%). Fluorescence activated cytometric analysis of CR1 and CR3 expression on PMNs from a randomly selected subgroup of patients with RA showed that the serum level of cytidine deaminase activity was correlated positively with the expression of CR1 (the C3b receptor) on the cell surface and that the proportion of polarised PMNs was positively correlated with the expression of CR3 (or CD11b/CD18), the iC3b receptor that is upregulated on activation. It is suggested that the polarised PMNs which circulate in blood samples from patients with RA represent cells which have been activated but not yet marginated, or activated cells which have marginated but subsequently returned to the circulating pool.

Adult↗
PubMed1992

Circulating von Willebrand factor in inflammatory bowel disease.

Raised circulating von Willebrand factor is a recognised marker of vascular injury. To evaluate the role of vascular injury in the pathogenesis of inflammatory bowel disease, serum von Willebrand factor in Crohn's disease, ulcerative colitis, confirmed bacterial diarrhoea, and healthy subjects was measured. von Willebrand factor values were raised in 9/14 patients (p = 0.007) with active Crohn's disease, 15/28 (p = 0.0004) with inactive Crohn's disease, 16/23 (p = 0.0003) with active ulcerative colitis, 9/27 (p = 0.04) with inactive ulcerative colitis, and 15/17 (p = 0.0001) patients with bacterial diarrhoea. Serum von Willebrand factor was unrelated to disease activity in Crohn's disease but was significantly raised in active (p = 0.02) compared with inactive ulcerative colitis. In contrast to controls, the detection of von Willebrand factor from inflammatory bowel disease sera and that from fractured endothelial cells was significantly inhibited by the reducing agent, dithiothreitol, suggesting the presence of an additional dithiothreitol sensitive form of the molecule derived from injured endothelial cells in inflammatory bowel disease. That serum von Willebrand factor is raised in quiescent as well as active Crohn's disease is compatible with the proposal that vascular injury is a fundamental abnormality in this disorder. The raised von Willebrand factor values in active inflammatory bowel disease and bacterial diarrhoea could be caused by either vascular injury, occurring secondary to bowel inflammation, or to an acute phase response resulting from endothelial cell stimulation by mediators released during the inflammatory process. Raised circulating von Willebrand factor could contribute to the increased risk of thrombosis associated with active inflammatory bowel disease.

Bacterial Infections↗
PubMed1992

Anti-neutrophil antibodies in inflammatory bowel disease: prevalence and diagnostic role.

Anti-neutrophil antibodies have been shown in sera from patients with a variety of inflammatory diseases. Those reacting with components of neutrophil cytoplasm are associated with systemic vasculitis. Both nuclear and perinuclear staining patterns on human neutrophils have been reported using sera from patients with inflammatory bowel disease. We have evaluated the reactivity against human neutrophils of sera from 100 patients with inflammatory bowel disease, 14 disease controls, and 20 normal volunteers. Altogether 27/50 (54%) sera from patients with ulcerative colitis contained antibodies that reacted with cytospun ethanol fixed neutrophils compared with 5/50 (10%) from Crohn's disease (p less than 0.001) and 0/34 control sera (p less than 0.001). All seven sera from patients with proctitis alone were negative (p less than 0.01). There was no correlation between presence or titre of anti-neutrophil antibodies and either disease activity or treatment. Positive sera gave three different staining patterns on human neutrophils. The predominant pattern was perinuclear (17/32); 12 sera gave a cytoplasmic and three a homogeneous nuclear staining pattern. None of the patients or the controls had antibodies to myeloperoxidase, elastase, or serine proteinase 3, all of which are recognised by anti-neutrophil cytoplasmic antibodies. Only 2/27 sera positive by indirect immunofluorescence reacted with an extract of neutrophil primary granules. In conclusion, anti-neutrophil antibodies occur more commonly in ulcerative colitis than in Crohn's disease or control subjects and the anti-neutrophil antibodies found in inflammatory bowel disease are different from those associated with vasculitis.

Adult↗
PubMed1991

Peripheral blood neutrophils in inflammatory bowel disease: morphological evidence of in vivo activation in active disease.

Morphological evidence of activation in vivo of circulating neutrophils in patients with inflammatory bowel disease (IBD) was sought by quantitative light microscope examination of toluidine blue-stained preparations made from peripheral venous bloods that had been fixed immediately ex vivo. The proportion of spherical (unactivated) circulating neutrophils was reduced in active Crohn's disease (73%; 46-96 (median; range), n = 11) compared with inactive Crohn's (90%; 45-99; n = 18, P less than 0.01) and normal subjects (94%; 44-98; n = 13, P less than 0.05). There tended to be fewer spherical neutrophils in active ulcerative colitis (77%; 13-96; n = 17) than in quiescent colitis (88%; 57-99, n = 13, P less than 0.1) or normal subjects (P less than 0.05). Activated neutrophils occur in the circulating pool of patients with active IBD and can be detected by light microscopy of peripheral venous blood leucocyte preparations.

Adult↗
PubMed1991

Characterisation of the size and composition of circulating immune complexes in patients with rheumatoid arthritis.

The size and composition of circulating immune complexes in the sera of patients with rheumatoid arthritis (RA) were studied in relation to different manifestations of the disease. Circulating immune complexes from the sera of 94 patients (50 with extra-articular disease) and 10 matched controls were fractionated by sucrose density gradient ultracentrifugation. The composition, immunoglobulin and rheumatoid factor (RF) concentrations within each of the fractions were determined by a sensitive enzyme linked immunosorbent assay (ELISA). Intermediate size (14S-21S) IgG complexes containing RF activity and 22S IgG-IgM RF complexes were found in the sera of 40 patients with RA, while intermediate size complexes of self associated IgG RF and larger size complexes (greater than 22S) of IgG RF and IgM RF were associated with extra-articular features of RA (50% of extra-articular disease). Complexes containing IgA were found in the sera of many patients with RA, and dimeric IgA RF mainly in patients with extra-articular disease. These results support the view that whereas small size circulating immune complexes are of no primary pathogenic importance in synovitis, large size (greater than 22S) circulating immune complexes may play a role in extra-articular disease in RA. Current understanding of the formation of large complexes provides a biological explanation for their occurrence and effects.

Antigen-Antibody Complex↗
PubMed1991

Brief exercise induces an immediate and a delayed leucocytosis.

Haematological profiles were measured: (1) before and for 5 h 30 min after 30 min sports (squash, swimming, jogging); and (2) before, during and for 2 h 30 min after 30 min cycle ergometry at workloads which required rates of oxygen consumption that were between 48% and 84% of maximal. In both instances exercise induced an immediate leucocytosis (owing to rises in both neutrophils and lymphocytes) which subsided rapidly at the finish of exercise and was followed by a delayed neutrophilia of greater magnitude which peaked at approximately 3 h after the start of exercise. Changes in plasma catecholamines and cortisol recorded during and after exercise (cycle ergometry only) support the hypothesis that the immediate leucocytosis during brief exercise is attributable to elevated catecholamine levels, whereas the delayed neutrophilia is due to raised cortisol levels.

Adult↗
PubMed1990

A rapid preparation technique for leucocytes.

A procedure is described for making leucocyte preparations from blood samples fixed ex vivo. Briefly, blood is treated with buffered formaldehyde and the erythrocytes and platelets removed subsequently by lysis and differential centrifugation. The fixed leucocyte preparations can then be processed or fixed further for various types of microscopy as required. In stained preparations examined by light microscopy, the different leucocytes, i.e. lymphocytes, polymorphonuclear leucocytes (PMN) and monocytes, can readily be identified by their characteristic nuclear morphology, and polarized PMN can easily be recognized by their non-spherical shape. Experiments with chemotaxins in vitro indicated that the procedure could be used to determine whether polarized PMN circulate in the blood of normal individuals and patients with inflammatory disease. A study of the blood from eleven normal subjects showed that 84.0 +/- 10.8% (mean +/- 2 SEM) of circulating PMN were spherical, while the majority of the remainder (14.3 +/- 10.5%) were only 'slightly' polarized.

B-Lymphocytes↗
PubMed1989

Spectroscopic studies on IgG aggregate formation.

Spectroscopic techniques have been used to examine the effects of IgG of heating, irradiation by ultraviolet light and exposure to glutaraldehyde. Relatively few changes were observed in treated IgG which remained unaggregated but several significant size-dependent changes were observed in aggregated IgG. These results suggest that IgG aggregate formation by cross-linking with glutaraldehyde involves the least perturbation of the basis IgG structure, whereas aggregate formation by heating involves the most, with ultraviolet irradiation occupying an intermediate position.

Glutaral↗
PubMed1989

Rapid clearance of the lupus antigen Sm is delayed by autoantibody: a possible mechanism of autoimmunity perpetuation.

Sm ribonucleoprotein complex was immunopurified and labelled with 125I. After i.v. injection into normal mice 125I-Sm was cleared with a half life of less than 3 min, mainly to the liver (54% at 15 min). With time there was a progressive reduction in liver uptake (13.3% at 1 h), and this was associated with the appearance of increasing amounts of trichloroacetic acid soluble 125I in serum, suggesting complete Sm catabolism. Injection of 125I-Sm as a preformed immune complex with human anti-Sm antibody was associated with slower antigen removal from the circulation (half life 15 min), more gradual liver uptake (27% at 1 hr), and less degradation products in the serum than after injection of antigen alone. These data suggest that release of 125I-Sm into the circulation is followed by specific organ uptake and antigen degradation. In the form of an immune complex, the rapid removal mechanism is impaired, and antigen persists in the circulation in an undegraded form. Simultaneous production of anti-Sm antibody and Sm antigen release following tissue destruction could lead to amplification of any primed immune response as a result of autoantigen drive in systemic lupus erythematosus.

Animals↗
PubMed1988

The leucocytosis of exercise. A review and model.

Exercise is known to induce an immediate leucocytosis, the magnitude of which is related, in most instances, to the intensity and duration of the work. On finishing exercise, however, the leucocyte count may change in any one of several different ways. The pattern of postexercise changes in the leucocyte count is determined mainly by the time which has elapsed since beginning exercise, rather than the work intensity or the total work done, if, for example, exercise has been intermittent. Consideration of, firstly, the circumstances under which the plasma concentrations of catecholamines and cortisol have been found separately to correlate with the leucocyte count at the finish of exercise, and, secondly, the effects on the leucocyte count of exogenous administration of these substances has led us to develop a model which can satisfactorily account for all of the principal changes in the leucocyte count that have been noted during and after exercise. It is proposed that catecholamines produced during exercise act to increase the ratio of circulating to non-circulating leucocytes, while cortisol acts, by a mechanism which involves a time lag, to increase the total number of leucocytes in the vascular compartment. Examination of previously published reports shows that many contain results which support this model. Using the model as a basis, some predictions are made that can be tested experimentally, and some experiments are suggested which should help elucidate the mode of action of catecholamines and cortisol.

Adolescent↗
PubMed1987

An evaluation of the Cell-Dyn 1000.

The Cell-Dyn 1000 is a new eight parameter fully automatic cell counter. This was evaluated following the ICSH guidelines. Scientific evaluation was generally satisfactory, largely conforming to the manufacturer's specifications. A number of potential microbiological safety hazards were noted; many could be overcome by minor modifications. Throughput and start-up/close-down times were acceptable. However, the reliability of the tested machine was felt to be less than satisfactory although this may be corrected by further minor machine modifications.

Blood Cell Count↗