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Biomedical subjects

A Murphy

Publications and source records attributed to A Murphy.

At least 19 recordsLinked to original sources
PubMed1995

Leukocyte function-associated antigen 1 (LFA-1) and CD44 are signalling molecules for cytoskeleton-dependent morphological changes in activated T cells.

Signaling through the leukocyte function-associated antigen 1 (LFA-1) molecule has previously been shown to induce homotypic aggregation in T cells and to induce cytoskeletal changes in T lymphoma cells. In this study we describe the induction of a dendritic phenotype associated with cytoskeletal rearrangement in activated human peripheral blood T cells stimulated with monoclonal antibody SPV-L7 to LFA-1 alpha. Maximal expression of this phenotype required 72 h preactivation with phorbol myristate acetate and expression was abolished using the protein kinase C inhibitor staurosporine. Monoclonal antibody to CD18, the beta-chain of LFA-1, did not induce this phenotype. Monoclonal antibody MEM 83 to presumably a discrete epitope on LFA-1 alpha did not induce this phenotype but induced homotypic aggregation. However, a monoclonal antibody to CD44 induced a similar phenotype in activated lymphocytes. Induction of both homotypic in activated lymphocytes. Induction of both homotypic aggregation and the dendritic phenotype was abolished by preincubation with soluble intracellular adhesion molecule 1 (ICAM-1). Cytoskeletal inhibitors prevented the morphological changes in SPV-L7-activated lymphocytes. Preincubation with tyrosine kinase inhibitor, protein kinase C inhibitors, and inhibitors of new protein synthesis also prevented these morphological changes. These data suggest that discrete epitopes on LFA-1 alpha may be capable of inducing discrete signals either for homotypic aggregation or for a dendritic phenotype. As both LFA-1 and CD44 are involved in the migration of lymphocytes through high endothelial venules, these data could suggest that these molecules transduce signals resulting in cytoskeletal modification necessary for lymphocyte transmigration.

Alkaloids↗
PubMed1995

In vivo assessment of catheter-tip PO2 sensor: sampling lumen fabrication.

Fabrication of the sampling lumen of an intra-arterial PO2 sensor is performed in standard catheters mechanically or by laser. Clinical evaluation is performed with respect to catheter insertion, complications, accuracy of oxygen sensor data and fibrin deposition on the catheter surface. The success rate for catheter insertion is 57% for 138 standard and 50% for 74 laser-cut catheters studied. The proportion of catheter failures (blocked or non-reading) is 14% in laser-cut compared with 30% in standard. These differences are not statistically significant at the 5% level. There is no clinically significant difference in sensor accuracy, with 37.5% of results within +/- 0.05 kPa and 80% within +/- 2.0 kPa of simultaneous blood gas values. Drift is within +/- 0.3 kPa h-1 for 78% of monitoring time. Significant errors of recalibration occur in 6% of calibrations. Scanning electron micrographs demonstrate a much smaller sampling lumen in the laser-cut group, but no reduction in fibrin deposition at the site of the sampling hole. The low success rate for catheter insertion is a problem because of cost implications. The accuracy of the system is usually sufficient for clinical purposes, provided the calibration is checked every 4 h.

Catheterization, Peripheral↗
PubMed1995

Expression of CD44 on rheumatoid synovial fluid lymphocytes.

OBJECTIVES: To investigate the involvement of the adhesion molecule CD44 in the homing of lymphocytes to synovial tissue, by examining the density of expression and molecular mass of CD44 on rheumatoid synovial fluid lymphocytes. METHODS: Twenty patients with rheumatoid arthritis were studied. Peripheral blood and synovial fluid lymphocytes were isolated by Ficoll-Hypaque sedimentation. CD44 expression was analysed by two colour flow cytometry of CD3 positive T lymphocytes with calculation of mean fluorescence intensity. Expression of activation markers M21C5, M2B3, interleukin (IL)-2 receptor and transferrin receptor was quantitated. In addition, CD44 molecular mass was examined by Western blot in six patients. RESULTS: CD44 expression was markedly increased on synovial fluid T lymphocytes of rheumatoid patients relative to peripheral blood lymphocytes from the same individuals. CD44 molecular mass on peripheral blood mononuclear cells was 88 kDa, but that on synovial fluid lymphocytes was only 83 kDa. CD44 expression correlated significantly with expression of activation markers M21C5, M2B3, and the IL-2 receptor. CONCLUSIONS: Alterations in density of expression or of the molecular mass of CD44 could contribute to local tissue injury, either directly by facilitating adhesion, or indirectly through effects on other adhesion molecules.

Arthritis, Rheumatoid↗
PubMed1995

Tyrosine phosphorylation in the human duodenum.

Many growth factor receptors including the epidermal growth factor receptor function through tyrosine kinase activity. The aim of this study was to examine the constitutive level of tyrosine phosphorylation in the normal duodenum and in the hyperproliferative coeliac duodenum. A flow cytometric assay was devised using monoclonal antibody to phosphorylated (but not native) tyrosine residues to determine the levels of tyrosine phosphorylation in both CD3 positive intraepithelial lymphocytes and CD3 negative epithelial cells obtained by EDTA treatment of endoscopically obtained duodenal biopsy specimens. In addition, immunohistochemistry was performed on 18 formalin fixed coeliac duodenal biopsy specimens and eight control specimens. Tyrosine phosphorylation could be detected by flow cytometry on duodenal enterocytes and this expression was up regulated by pretreatment with epidermal growth factor. Tyrosine phosphorylation decreased with progression from the villus to the crypt, however, and was virtually undetectable on crypt enterocytes. Immunohistochemistry of the coeliac duodenum showed virtually absent tyrosine phosphorylation in the crypt. Increased tyrosine phosphorylation was detected in the infiltrating T cells. In conclusion, tyrosine phosphorylation in the duodenum is confined to the non-proliferative villous epithelium and is virtually undetectable in the proliferative crypt compartment. These findings suggest that tyrosine kinase activity is not a significant factor in the regulation of crypt cell proliferation in the human duodenum either in normal subjects or in coeliac disease patients.

CD3 Complex↗
PubMed1994

ChlVPP/PABlOE and radiotherapy in advanced Hodgkin's disease. The Central Lymphoma Group.

PURPOSE: The United Kingdom Central Lymphoma Group (CLG) has modified mechlorethamine, vincristine, procarbazine, and prednisone/doxorubicin, bleomycin, vinblastine, and dacarbazine (MOPP/ABVD) by substituting mechlorethamine with chlorambucil and dacarbazine with etoposide in the treatment of patients with advanced Hodgkin's disease (HD). Prednisolone is included in the bleomycin-containing combination, and the vinca alkaloids have been switched to balance the myelotoxicity of the two component regimens. PATIENTS AND METHODS: The resulting ChlVPP/PABlOE regimen is as follows: on days 1 to 14, chlorambucil 6 mg/m2 orally, procarbazine 100 mg/m2 orally, and prednisolone 30 mg/m2 orally; on days 1 and 8, vinblastine 6 mg/m2 intravenously (i.v.); on day 29, doxorubicin 40 mg/m2 i.v.; on days 29 and 36, vincristine 1.4 mg/m2 (maximum, 2 mg) i.v., and bleomycin 10 mg/m2 i.v.; on days 30, 31, and 32, etoposide 200 mg/m2/d orally; on days 29 to 43, inclusive, prednisolone, 30 mg/m2 orally. The second full cycle restarts on day 50. Treatment continues to maximum response plus two full cycles, but with a minimum of three full cycles. Radiotherapy is administered, after chemotherapy, to sites of previously bulky disease. Since 1983, 216 patients with previously untreated, advanced Hodgkin's disease (HD) have entered this study. RESULTS: The complete remission (CR) rate after chemotherapy was 73% (95% confidence interval [CI], 67% to 79%), and after additional radiotherapy was 85% (95% CI, 80% to 90%). The failure-free survival (FFS) rate at 5 years was 68% (95% CI, 61% to 74%), and the overall actuarial survival at 5 years was 78% (95% CI, 72% to 84%). The CR rate in patients in the poorer prognostic categories was high: 81% in patients with albumin levels less than 37 g/L, 79% in patients older than 40 years of age, 84% in stages IIIB plus i.v. disease, and 79% in patients presenting with B symptoms. As expected, nausea and vomiting were not major problems, although infection, often in the context of myelosuppression, complicated almost half the cases, and 29% of patients required admission at some stage for treatment of infection. CONCLUSION: In this multicenter study, ChlVPP/PABlOE produced results comparable to those reported for MOPP/ABVD, but with less nausea and vomiting. Treatment duration was shorter than in the original MOPP/ABVD regimen, and than that used in the Cancer and Leukemia Group B (CALGB) trial. It will now be compared with PABlOE alone.

Adult↗
PubMed1990

Leukocyte function-associated antigen 1 (LFA-1) is a signaling molecule for cytoskeletal changes in a human T cell line.

The HuT 78/2 clone is a human T cell clone which has an activated phenotype. When this line was stimulated with immobilized antibody to LFA-1, the majority of cells developed dendritic processes. These processes were demonstrated to contain cytoskeletal elements including microtubules and intermediate filaments. Phorbol myristate acetate synergized with and prolonged this effect. Thus, the LFA-1 molecule may function as a signaling molecule for cytoskeletal reorganization in a human T cell clone.

Antibodies, Monoclonal↗
PubMed1990

Antinuclear antibodies in sera of patients with recurrent pregnancy wastage.

Four groups of women were studied to determine whether low-level antinuclear antibody titers are associated with a higher risk for pregnancy loss. Group A consisted of 30 patients with a history of unexplained fetal losses. Group B consisted of 30 women with "explained" fetal losses (e.g., uterine septum or luteal phase defect). Ages and number of losses were comparable between the women in groups A and B. Group C consisted of 61 healthy pregnant women. Group D involved 61 healthy nonpregnant women of reproductive age. In groups A and B, 40% and 53.3% of the respective patients had antinuclear antibody titers greater than or equal to 1:40. In groups C and D the frequencies of positive antinuclear antibody titers were 8.2% and 5.6%, respectively. This study demonstrates a high prevalence of low-titer antinuclear antibody-positive serum in patients with explained and unexplained pregnancy losses.

Abortion, Habitual↗
PubMed1990

Spectrophotometric quantitation of anchorage-dependent cell numbers using the bicinchoninic acid protein assay reagent.

A rapid and convenient method is described for the determination of the actual and relative number of adherent cells in tissue culture. The cell lines human melanoma C32, ATCC CRL 1585, mouse melanoma B16-F10, and pig epithelial LLC-PK1, suspended in Dulbecco's minimum essential medium containing no serum, were allowed to adhere to fibronectin adsorbed to wells of a 96-well microtiter plate. Nonadherent cells were removed by aspiration, wells were washed, and adherent cells were solubilized with 200 microliters of the bicinchoninic acid (4,4'-dicarboxy-2,2'-biquinoline) protein assay reagent. Plates were heated to 60 degrees C for 30 min and absorbances read at 562 nm using a microtiter plate reader. A linear correlation was observed between the number of adherent cells in the range 2-8 X 10(5)/ml cells added and the protein content of the adherent cells as measured by the BCA protein reagent. The assay procedure gave absorbance values in the range of 0.100 to 1.30 making the method highly sensitive and reproducible. Blank wells containing only coupled protein and no cells gave little or no absorbance. Cell adhesion was fibronectin specific since little or no cell attachment was observed when microtiter plates were coupled with bovine serum albumin. Similar results were obtained with other cell types such as platelets. These results indicate that measurement of total cellular protein using the BCA protein reagent can be a rapid and sensitive assay for the detection and quantitation of adherent cells.

Animals↗
PubMed1990

Effect of low-dose oral contraceptive on gonadotropins, androgens, and sex hormone binding globulin in nonhirsute women.

The effectiveness of a low-dose oral contraceptive (OC) in suppressing plasma levels of gonadotropins, ovarian, and adrenal androgens and stimulating sex hormone-binding globulin (SHBG) was evaluated prospectively in nonhirsute women. Thirty-three women ingested 35 micrograms of ethinyl estradiol and 1 mg of norethindrone beginning within day 1 to 5 of the menstrual cycle. Baseline levels of luteinizing hormone, follicle-stimulating hormone, total testosterone (T), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), and SHBG were obtained before ingestion of the OC and repeated after 3, 6 and, 9 months of OC use on day 1 to 5 of the OC "cycle". A significant suppression of gonadotropin levels is seen in nonhirsute women. Sex hormone binding globulin is consistently stimulated by the low-dose OC. A significant suppression of T and DHEAS is observed. No change was seen in levels of A. The demonstrated effects become evident at 3 months and are maintained at 6 and 9 months.

Adolescent↗
PubMed1989

The interaction of thrombospondin with platelet glycoprotein GPIIb-IIIa.

The interaction of human platelet thrombospondin (TSP) with human platelet glycoproteins GPIIb-IIIa was studied using a solid-phase binding assay. Polystyrene test tubes were coated with TSP, and 125I-labeled GPIIb-IIIa was added, allowed to bind, and the bound radioactivity was measured. After 90 min, the binding became time independent, and in most experiments, more than 10% of the exogenously added radioactivity was bound to the tube. Analysis of the bound radioactivity by polyacrylamide gel electrophoresis and autoradiography indicated that it was from labeled GPIIb-IIIa. Several lines of evidence indicate that the binding of GPIIb-IIIa to TSP was specific. (a) TSP immobilized on plastic or Sepharose bound 3-10-fold more GPIIb-IIIa than immobilized bovine serum albumin. (b) Addition of unlabeled excess GPIIb-IIIa reversed the binding of 125I-labeled GPIIb-IIIa to immobilized TSP. (c) Addition of EDTA inhibited the binding of GPIIb-IIIa to TSP by more than 90%, whereas addition of 1 mM CaCl2 and 1 mM MgCl2 potentiated the binding by more than 100%. (d) Monoclonal antibodies against TSP and GPIIb-IIIa inhibited the binding by 30-70% as compared with control and polyclonal anti-fibrinogen anti-serum. (e) A plot of GPIIb-IIIa bound versus GPIIb-IIIa added was best described as a rectangular hyperbola by regression analysis with half-saturation at 60 ng/ml GPIIb-IIIa. Similar results were obtained when labeled TSP was added to tubes coated with GPIIb-IIIa. These results show that TSP and GPIIb-IIIa can specifically interact in vitro and suggest that GPIIb-IIIa may function as a platelet TSP receptor during platelet aggregation.

Calcium↗
PubMed1989

The GPIIB-IIIa-like complex may function as a human melanoma cell adhesion receptor for thrombospondin.

The purpose of this study was to determine whether a heterodimeric complex immunologically related to the fibrinogen receptor could function as a thrombospondin (TSP) receptor in TSP-mediated cell-substratum adhesion of human melanoma cells. We found that polyclonal antibodies to the platelet GPIIb-IIIa complex, GPIIIa, and the human vitronectin receptor inhibited TSP-mediated cell adhesion by 63-68%. Immunoprecipitation of detergent extracts of 125I-surface-labeled melanoma cells using either anti-human platelet GPIIb-IIIa or anti-human vitronectin receptor antibody revealed the presence of a single heterodimeric complex, suggesting that both antisera recognize the same integrin receptor, GPIIb-IIIa-like antigen. Adhesion of cells to TSP is likely mediated through a region of the TSP molecule containing the arginine-glycine-aspartic (RGD) peptide sequence, since cell attachment to TSP was inhibited 50-66% in the presence of peptides containing RGD. These results strongly suggest that a GPIIb-IIIa-like/vitronectin receptor can serve as a cell binding site for TSP in mediating cell-substratum adhesion.

Antibodies, Monoclonal↗
PubMed1989

Mammographic localization and biopsy: the experience of a gynecologic oncology group.

From 1976 through 1986, two hundred eighty or 9% of all breast biopsies performed by a private gynecologic oncology group were for mammographically suspicious but occult breast lesions. Sixteen percent were found to be malignant. There has been improvement in mammographic techniques, and localization procedures have evolved to the current use of hooked-wire needles, which allow for the excision of smaller amounts of tissue and use of outpatient surgery facilities. Recently, the cancers encountered have been more often carcinoma in situ rather than invasive lesions. With the current increase in mammographic screening, there needs to be a continuing evolution in diagnostic modalities.

Adult↗
PubMed1989

Postoperative recuperation: relation to the extent of endoscopic surgery.

Ninety patients undergoing a total of 92 endoscopic procedures were assessed regarding their subjective recovery times, their delays in returning to their places of employment, the duration of analgesic use, and their inhospital stays. A significant association (P less than 0.05) between recuperation parameters and the extent of the intra-abdominal surgery at laparoscopy was observed. A weak association also was noted between the number of incisions performed, the duration of surgery, and postoperative recuperation. Nonetheless, even the most radical endoscopic procedures required considerably less recuperation time when compared with laparotomies. With the out-of-work period reduced 5- to 6-fold, obese individuals appeared to tolerate these procedures as well as their thin counterparts.

Abdomen↗