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B L Evatt

Publications and source records attributed to B L Evatt.

At least 55 records · Page 3Linked to original sources
PubMed1996

TNF-alpha suppresses IL-6 upregulation of protein S in HepG-2 hepatoma cells.

The pathogenesis of disseminated intravascular coagulation (DIC) has, in part, been attributed to the impairment of the natural anticoagulant protein C/protein S pathway. DIC, which frequently occurs during sepsis, has been linked to cytokines that can induce or modulate procoagulant activity. Three of these cytokines, IL-1 alpha, IL-6, and TNF-alpha have been reported to be increased in the early stages of sepsis. In the present study, we have stimulated HepG-2 hepatoma cell cultures with recombinant human IL-1 alpha, IL-6, TNF-alpha, and oncostatin M (OSM). The results demonstrated that TNF-alpha, and to a lesser degree, IL-1 alpha, could significantly suppress IL-6 upregulation of protein S, whereas the effects of OSM was only suppressed by the combination of IL-1 alpha and TNF-alpha. The combination of IL-1 alpha and TNF-alpha also suppressed protein S production below that of control or basal levels. These results indicate that IL-1 alpha and TNF-alpha may play important regulatory roles in coagulation.

Antineoplastic Agents↗
PubMed1996

Attitudes, practices, and infection risks of hemophilia treatment center nurses who teach infection control for the home.

OBJECTIVE: To examine the practices toward infection control training and to assess the attitudes about, and risks for, exposures to blood among hemophilia treatment center (HTC) nurses who teach home infusion therapy (HIT). DESIGN AND POPULATION: Written and telephone interview surveys of the 153 nurses who teach HIT at federally funded HTCs. MAIN OUTCOME MEASURES: Hemophilia treatment center nurses' teaching practices and infection control messages taught, and frequency of exposures to blood. RESULTS: The response rate to the written nurses' survey was 60% and to the telephone interview 88%. Nurses taught patients a median of three HIT sessions totaling 4 hours of instruction. Reevaluation of patients' HIT practices took place every 6 months by 22% and every 12 months by 59% of nurses. Nurses frequently reported teaching proper use of a sharps disposal container (99%) and gloves (93%), but less often reported teaching patients to wash hands after infusions (26%) and to report needlestick injuries to HTCs (11%). The respondents identified several barriers to effective infection control as it is practiced in the home by patients. Although at least 30% of HTC nurses recalled having had percutaneous exposure to blood, they considered their risk for hepatitis B infection low but greater than for infection with the human immunodeficiency virus (HIV). CONCLUSIONS: While some important infection control messages are stressed during HIT teaching, others may be underemphasized. Failure to instruct patients about all infection control precautions may be related to nurse educators' perception of low to moderate personal risk for hepatitis B and HIV infection. Patients receiving HIT, and those who assist them, need to be fully aware of, and to have reinforced periodically, universal infection control strategies in the home.

Health Knowledge, Attitudes, Practice↗
PubMed1995

Hemostatic properties of the SV-40 transfected human microvascular endothelial cell line (HMEC-1). A representative in vitro model for microvascular endothelium.

HMEC-1 is a SV-40T transfected human microvascular endothelial cell line that constitutively expresses RNA transcripts for plasminogen activator inhibitor 1 (PAI-1), tissue-type plasminogen activator (t-PA), protein S (PS), von Willebrand factor (vWF), and thrombomodulin. Tissue factor (TF) can be induced in response to stimulation with tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1alpha) and phorbol 12-myristate 13-acetate (PMA). Proteins corresponding to PAI-1, t-PA, protein S and vWF genes were constitutively released in the culture supernatant. This cell line is a model that will be useful to investigate coagulation/fibrinolytic properties of microvascular endothelium.

Basal Metabolism↗
PubMed1995

IL-6 upregulates protein S expression in the HepG-2 hepatoma cells.

Several pro-inflammatory cytokines have been shown to be important in the modulation of the procoagulant response. However, what role these cytokines may have in the regulation of coagulation inhibitors is poorly understood. While the hepatocyte is a primary site of synthesis for the anticoagulant protein C and S, it is also a major target cell for the proinflammatory cytokine, IL-6. We have found that stimulation of HepG-2 hepatoma cells with IL-6 (5 ng/ ml) significantly increased the production of the anticoagulant cofactor, protein S, in both a time and dose dependent fashion. This increase was seen at both the RNA and protein level. A mouse monoclonal neutralizing antibody to human IL-6 suppressed the IL-6 effect in a concentration dependent fashion. IL-6 also increased the release of the C4b-binding protein but had no effect on protein C production. When combined with either dexamethasone or soluble IL-6 receptor, the IL-6 response was significantly enhanced. Oncostatin M, a functionally related cytokine, had a similar effect while other related cytokines, IL-11 and leukemia inhibitory factor, only had a marginal effect. IL-1, TGF-beta, and TNF-alpha had no significant effect on protein S production. These results indicate that IL-6 may play an important regulatory role in the anti-coagulant pathway.

Animals↗
PubMed1994

Tumor necrosis factor-alpha downregulates protein S secretion in human microvascular and umbilical vein endothelial cells but not in the HepG-2 hepatoma cell line.

Protein S deficiency, which is associated with thrombosis, can either be inherited or acquired. Recently, we reported that a decrease in free protein S was observed in 19 of 25 persons with HIV/AIDS. The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), has been reported to be elevated in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients and has been shown to induce a procoagulant state on the surface of endothelial cells. We report here that recombinant TNF-alpha (rTNF-alpha) downregulated protein S synthesis in the SV-40T transfected human microvascular endothelial cell line (HMEC-1) model system by approximately 70% and in primary human umbilical vein and dermal microvascular endothelial cell cultures by approximately 50%. Using the HMEC-1 model, Northern blot analysis showed a decrease in protein S RNA at 24 hours that was corroborated by Western blot analysis and enzyme-linked immunosorbent assay (ELISA) quantification. Evidence supporting the specificity of the TNF-alpha effect included the following: (1) TNF-alpha down-regulation of protein S was completely blocked by TNF neutralizing antibody; (2) the effect was transient, and protein S was restored to near normal levels after TNF was removed from cell cultures; (3) an antibody directed to the TNF RI (55-kD receptor) was shown to mimic the action of TNF-alpha on HMEC-1 cells; and (4) other proinflammatory cytokines, interleukin (IL)-1, IL-6, and TGF-beta, had no effect on protein S secretion. However, TNF-alpha showed no regulatory control over protein S synthesis in the human hepatocellular carcinoma cell line HepG-2. We suggest that TNF-alpha downregulation of protein S may be a mechanism for localized procoagulant activity and thrombosis recently reported in some AIDS patients with associated protein S deficiency.

Carcinoma, Hepatocellular↗
PubMed1994

Relative antithrombotic effects of monoclonal antibodies targeting different platelet glycoprotein-adhesive molecule interactions in nonhuman primates.

The relative antithrombotic effectiveness of targeting glycoprotein (GP) Ib-dependent versus GPIIb-IIIa-dependent platelet interactions has been determined in baboons by measuring thrombus formation after infusing comparable antihemostatic doses of anti-von Willebrand factor (vWF) monoclonal antibody (MoAb) BB3-BD5, anti-GPIb MoAb AP1, and anti-GPIIb-IIIa MoAb LJ-CP8 under conditions of arterial and venous flow (shear rates of 750 to 1,000 seconds-1 and 100 seconds-1, respectively). Thrombus formation was quantified as 111In-platelet deposition and 125I-fibrin accumulation on segments of collagen-coated tubing interposed in chronic exteriorized arteriovenous (AV) shunts for 40 minutes. In vitro, anti-vWF MoAb BB3 BD5 (IgG) and anti-GPIb MoAb AP1 [IgG or F(ab)2 fragments] inhibited ristocetin-induced platelet aggregation (IC50 50 nmol/L and 1 mumol/L, respectively), but neither of these MoAbs blocked platelet aggregation induced by adenosine diphosphate (ADP) (P > .5). Conversely, anti-GPIIb-IIIa MoAb LJ-CP8 inhibited platelet aggregation induced by ADP (IC50 1 mumol/L, but failed to block ristocetin-induced platelet aggregation (P > .5). In vivo, the intravenous infusion of anti-vWF MoAb BB3 BD5 or anti-GPIIb-IIIa MoAb LJ-CP8 into baboons at doses that abolished corresponding agonist-induced aggregation ex vivo (bolus injections of 0.5 mg/kg and 10 mg/kg, respectively) prolonged template bleeding times from baseline values of 4.0 +/- 0.3 minutes to > 27 +/- 4 minutes, and to > 26 +/- 4 minutes, respectively (P < .001 in both cases), without affecting the peripheral platelet count (P > .5). However, injection of anti-GPIb MoAb AP1 [10 mg/kg as IgG or 1 mg/kg as F(ab)2 fragments] produced immediate irreversible thrombocytopenia (< 40,000 platelets/microL). Anti-GPIIb-IIIa MoAb LJ-CP8 abolished platelet deposition and fibrin accumulation on collagen segments under both arterial and venous flow conditions (P < .01 in all cases), whereas MoAb BB3 BD5 produced minimal inhibition of platelet deposition and no decrease in fibrin accumulation at arterial shear rates and undetectable antithrombotic outcomes at low shear. Thus, inhibiting GPIIb-IIIa-dependent platelet recruitment abrogates both thrombus formation and platelet hemostatic function at both venous and arterial shear rates. By contrast, interfering with GPIb-vWF-dependent platelet interactions abolishes platelet hemostatic function without producing corresponding antithrombotic effects.

Animals↗
PubMed1994

Changes in longevity and causes of death among persons with hemophilia A.

To examine recent changes in longevity and the causes of death among persons with hemophilia A, we evaluated death certificate data for persons who died in the United States from 1968 through 1989 and had hemophilia A or congenital Factor VIII disorder (ICD code 286.0) listed on the death certificate as one of the multiple causes of death. Multiple-cause-of-death mortality data for the United States from 1968 to 1989 were examined to compare death rates by year, focusing on death rates and causes of death for 1979-1981, 1983-1985, and 1987-1989. Gender, age group, race, geographic region, and median age at death of persons with hemophilia A and human immunodeficiency virus (HIV)-related disease listed as a cause of death were compared with those with hemophilia A without HIV-related disease. From 1968 through 1989, 2,792 hemophilia A deaths were reported. The death rate increased from 0.5 to 1.3 per 1,000,000 persons. From 1979-1981 through 1987-1989, mortality increased in all age groups above 9 years of age and age at death shifted markedly to lower ages. Median age at death decreased from 57 years in 1979-1981 to 40 years in 1987-1989. The percentage of deaths due to hemorrhage or diseases of the circulatory system decreased markedly as the result of the increase in deaths associated with HIV infection or infections other than HIV infection. Spread of HIV-1 infection in persons with hemophilia A has disrupted the reduction in mortality seen with factor replacement therapy, implementation of home care, and use of comprehensive hemophilia treatment centers. It is hoped that advances in the care of HIV-infected persons will improve survival in the hemophilia community.

Adolescent↗
PubMed1994

Development of an ELISA for quantification of human protein S in cell culture fluids using commercial polyclonal antisera.

An enzyme-linked immunosorbent assay (ELISA) was developed to measure protein S antigen released into cell culture fluids. We used readily available commercial polyclonal antisera to develop the assay. This assay was sensitive with a detection limit of about 0.086 ng/ml. Between-assay precision (coefficient of variation) at levels of 0.2, 1.1, and 13.9 ng/ml was 14%, 15%, and 11% respectively. Specificity and accuracy were demonstrated from the use of: 1) culture fluids from 3-primary endothelial cell cultures and 7-cell lines known to constitutively produce protein S; 2) 2-cell lines not synthesizing protein S; and 3) from selected samples of normal and protein S deficient plasma. The ELISA described here was about 12-fold more sensitive and 40-fold more cost effective when compared to a commercial ELISA kit. Thus the assay provided a sensitive, specific, precise and economical method useful for the measurement of the nanogram amounts of protein S commonly encountered in cell culture fluids.

Cell Line↗
PubMed1993

Precision of genotyping of Epstein-Barr virus by polymerase chain reaction using three gene loci (EBNA-2, EBNA-3C, and EBER): predominance of type A virus associated with Hodgkin's disease.

To precisely determine the genotype of Epstein-Barr virus (EBV) in Hodgkin's disease (HD), we simultaneously analyzed three divergent gene loci (EBNA-2, EBNA-3C, and EBER) that distinguish type A and B viruses. The primers designed to amplify these three gene loci encompass either type-specific deletion sequences (EBNA-2 and EBNA-3C) or type-specific point mutations (EBER) that identify the virus strain based on the sizes of the polymerase chain reaction (PCR)-amplified products or the mobility shifts in single-strand conformation polymorphism analysis. The locations of point mutations were identified by direct sequencing of the PCR-amplified DNA. We analyzed 15 EBV-infected cell lines and found a good correlation between EBNA-2 and EBNA-3C typing results. In contrast, approximately 33% of the cell lines analyzed maintained type A sequences in EBNA-2 and EBNA-3C genes while carrying type B sequences in the EBER region. Data obtained from analysis of cell lines served as a reference for studying HD samples. EBV DNA was detected in about 70% of HD. Among the EBV-positive samples, 56% were associated with type A virus, 13% with type B, and 31% with dual viral sequences. Thus, type A virus is predominant in HD. Based on the histology, the frequencies of EBV positivity were 83%, 71%, and 33% for mixed cellularity, nodular sclerosis, and lymphocyte predominance, respectively. The detection of high frequency of both type A and B sequences in HD may provide a lead in investigating the role of dual viral infection in EBV pathogenesis.

Antigens, Viral↗
PubMed1993

Protein S deficiency in men with long-term human immunodeficiency virus infection.

Decreases in protein S levels have recently been reported in some human immunodeficiency virus (HIV)-infected patients. To examine predisposing factors, 25 men randomly selected from a long-term study of HIV-infected patients were studied. The minimum mean duration of HIV seropositivity in this group was 106.6 months (range 15 to 143 months). No patients were anticoagulated at the time of the study. Three of the 25 randomly selected patients gave a history of thrombosis, in each instance occurring after the onset of HIV positivity. Two of the 3 patients with thrombosis had more than one episode. Coagulation studies showed that 3 of 3 (100%) of the patients with thrombosis and 16 of 22 (72.7%) of those without previous thrombosis had decreased free protein S. Mean-free and total protein S levels were statistically lower for HIV-infected patients with and without previous thrombosis compared with healthy male controls. C4b-binding protein was not increased in study patients with decreased protein S levels. Decreases in protein S levels did not correlate with CD4+ cell levels, CDC class, p24 antigen positivity, zidovudine (AZT) use, or Pneumocystis carinii prophylaxis. The duration of disease statistically correlated with decreases in protein S levels (r = .37, P < .05). A linear correlation existed between increasing IgG anticardiolipin antibody levels and decreasing free protein S antigen (r = .67, P < .005). This study shows that protein S deficiency is common in long-term HIV-infected patients and is caused by a decrease in the free protein, rather than by changes in the bound complex. The data suggest that protein S deficiency is not correlated with HIV disease severity but may predispose patients to thromboembolic complications.

Adult↗
PubMed1993

Cross-reactivity of 75 monoclonal antibodies to human immunoglobulin with sera of non-human primates.

We systematically analyzed a panel of 75 murine monoclonal antibodies (mAbs) reactive with human immunoglobulins IgG, IgA, IgM, IgD, and kappa and lambda light chains for reactivity with serum immunoglobulins of higher primates. In the great apes, and to a lesser extent in other primates, epitopes related to human light chains, IgM, IgA, IgD, and all 4 IgG subclasses were identified with many of the mAbs. Those mAbs identified as reactive with a given species may be useful for immunologic studies of these species. Cladistic analysis of antigenic relatedness generated a phylogenetic tree consistent with current anatomic or molecular taxonomies.

Animals↗
PubMed1993

Hemophilia growth and development study. Design, methods, and entry data.

PURPOSE: The study design, research questions, and baseline data are presented from a multicenter longitudinal epidemiologic investigation of the impact of human immunodeficiency virus (HIV) infection on three areas of functioning in children and adolescents with hemophilia: physical growth and sexual maturation, immune function, and neurological and neuropsychological functioning. PATIENTS AND METHODS: Sixty-nine percent (n = 333) of a population of males between the ages of 6 and 19 years with moderate to severe hemophilia participated in a comprehensive baseline examination. Approximately 62% of the study group was HIV seropositive and 38% HIV seronegative. RESULTS: Adjusted for age, HIV-positive participants were three times as likely as HIV-negative participants to exhibit declines in height-for-age attainment (p = 0.05), twice as likely to have delays in sexual maturation (p = 0.414), and more than three times as likely to exhibit antibody levels that were not indicative of prior exposure or vaccination (p < 0.001). In addition, analysis of a comprehensive battery of neuropsychological tests showed that HIV-positive participants were 50% more likely to show scores approximately 1 SD below expected levels in three of nine functional areas (p = NS) compared with HIV-negative participants. CONCLUSIONS: Entry data for this study reveal a greater likelihood for HIV-positive children and adolescents with moderate to severe hemophilia to have abnormal growth, and to exhibit antibody levels not indicative of prior exposure to disease or vaccination, which could be attributed to HIV infection. Lowered neuropsychological test performance in both groups may be attributable to the deleterious effects of chronic illness. Data are being collected from a group of non-HIV infected non-hemophiliac siblings for comparison.

Adolescent↗
PubMed1993

Protein S, an antithrombotic factor, is synthesized and released by neural tumor cells.

Protein S, an anticoagulant factor in the protein C antithrombotic pathway, was found to be synthesized and released by six tumor cell lines of neural origin by western blotting and ELISA. The rate of synthesis ranged from three- to 11-fold higher than that of a microvascular endothelial cell line and 36-144% that of a hepatoma cell line. The secreted protein S displayed specific anticoagulant activity similar to that of purified plasma protein S, implying that it was fully gamma-carboxylated. Ten primary brain tumor tissues also expressed protein S antigen, as shown by western blot analysis. Expression of anticoagulantly active protein S by neural cells raises important questions concerning possible physiologic roles for this multidomain protein beyond its function in control of thrombosis.

Blotting, Western↗
PubMed1993

Replication of Colorado tick fever virus within human hematopoietic progenitor cells.

Significant neutropenia, as well as thrombocytopenia and a mild anemia, occurs in patients infected with Colorado tick fever virus. In this study, human bone marrow CD34+ cells and KG-1a cells, a human hematopoietic progenitor cell line, were infected in vitro with Colorado tick fever virus. The time course and morphological appearance of viral replication in human progenitor cells were similar to those seen in erythroblasts and in HEL cells and suggest one possible mechanism for the clinical hematologic findings.

Animals↗
PubMed1992

Differential effects of sequential, simultaneous, and single agent interleukin-3 and granulocyte-macrophage colony-stimulating factor on megakaryocyte maturation and platelet response in primates.

Recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) following interleukin-3 (IL-3) priming has been shown to increase thrombopoiesis. To elucidate the comparative abilities of IL-3 and GM-CSF in influencing megakaryocyte development in vivo, serial bone marrow analyses were performed on rhesus monkeys treated with 5 micrograms/kg/d of IL-3 and 5 micrograms/kg/d of GM-CSF sequentially for 4 days each, simultaneously for 8 days, and as single agents for 8 days. Platelet counts maximally increased to a mean of 7.5 x 10(5)/microL (n = 3) on days 11 through 12 in monkeys treated with sequential IL-3/GM-CSF. In contrast, neither IL-3 alone nor simultaneously administered IL-3/GM-CSF elicited increases in thrombopoiesis between days 3 and 15. GM-CSF elicited a variable platelet response. Megakaryocyte ploidy distributions were significantly (P < .001) shifted between days 7 and 10 in monkeys treated sequentially and between days 3 and 15 in monkeys treated with combined IL-3/GM-CSF and with GM-CSF alone but not in monkeys treated with IL-3 alone. The changes in mean DNA content and megakaryocyte size, as determined by digital image analysis, were larger in monkeys treated with sequential IL-3/GM-CSF and with GM-CSF alone than in simultaneously treated monkeys. In addition, sequentially but not simultaneously treated monkeys showed increased numbers of megakaryocytes on bone marrow biopsy. We conclude that administration of IL-3 followed by GM-CSF treatment increases thrombopoiesis by sequentially increasing megakaryocyte numbers and maturation and that these effects are diminished by simultaneous administration of the two cytokines.

Animals↗
PubMed1992

Human lymphotropic retroviruses associated with mycosis fungoides: evidence that human T-cell lymphotropic virus type II (HTLV-II) as well as HTLV-I may play a role in the disease.

The human T-cell lymphotropic virus type I (HTLV-I) is causally associated with adult T-cell leukemia, but its role in mycosis fungoides (MF) has remained enigmatic. The virus is suspect because a small percentage of patients with MF have antibodies to it, the cells of others harbor deleted HTLV-I proviral sequences, and particles resembling HTLV-I emerge in cultured blood lymphocytes obtained from most patients. An alternative possibility is that disparate lymphotropic retroviruses may infect or affect a population of epidermotropic lymphocytes, leading to the same outcome, ie, MF. In studies designed to identify the particles detected in lymphocyte cultures of nine patients with a diagnosis of skin involvement characteristic of MF, this concept has gained support. While the cells of four patients provided evidence of HTLV-I infection, molecular hybridization with HTLV-II-specific pol probes showed HTLV-II in the cells of another patient. The 103-bp fragment amplified by the HTLV-II-specific probe was sequenced and proved to have greater than 90% homology with the same fragment amplified from cells known to be infected with HTLV-II. A role for HTLV-II in MF has not been suggested heretofore. Therefore, HTLV-I, HTLV-II, and their incomplete forms may be found in cells of MF patients, suggesting new theories regarding the pathogenesis of this disease.

Base Sequence↗
PubMed1992

Survival of hemophilic males with acquired immunodeficiency syndrome with and without risk factors for AIDS other than hemophilia.

Between January 1, 1981, and June 30, 1990, 1,514 hemophilia-associated acquired immunodeficiency syndrome (AIDS) cases in males were diagnosed in the United States. In 1,394, hemophilia was reported as the sole risk factor. For an additional 120, other risk factors were reported: of 101 of these, 40 had homosexual/bisexual activity, 53 had a history of intravenous drug use, and 8 had both of these risk factors. We examined the demographic data and the survival data of two principal groups: males for whom hemophilia was the sole reported risk factor for human immunodeficiency virus (HIV) exposure, and hemophilic males for whom homosexual/bisexual activity, intravenous drug use, or both of these additional risk factors were reported. The survival curves showed marginal differences between the hemophilia-only and the multiple risk groups; the median survival times were 13.1 and 14.6 months, with the cumulative probability of survival at 1 year as 52.7% and 54.0%, respectively. Kaposi's sarcoma was among AIDS indicator diseases more commonly found in the multiple risk factor group. Pneumocystis carinii pneumonia was the sole reported diagnosis indicative of AIDS for 34.4% of those in the hemophilia-only group, compared with 20.8% of those with multiple risk factors. The principal demographic difference between the two groups was the age distribution; those in the multiple risk factor group were primarily between 20 and 44 years of age. Restricting the analysis to those between 20 and 44 years resulted in a slightly longer survival time in the hemophilia-only group and no appreciable difference between the disease distributions and survival curves of the two groups.

Acquired Immunodeficiency Syndrome↗