Gamma-carboxylated isoforms of recombinant human protein S with different biologic properties

Human protein S (HPS), a regulator of hemostasis, is a vitamin K- dependent plasma protein with potential clinical utility. We have obtained high-level expression of the cDNA for HPS in two mammalian cell lines. Both cell lines secreted single chain recombinant HPS (rHPS) in serum-free medium as determined by Western blot analysis. The ability of the rHPS from both cell lines to act as a cofactor for human protein C (HPC) was determined; the rHPS secreted from the human 293 cell line had an activity six times that of the rHPS from the AV12-664 Syrian hamster cell line. Furthermore, the relative specific cofactor activity of rHPS from the 293 cell line was actually 2.5-fold higher than that of single-chain human plasma-derived HPS. Essentially all of the rHPS secreted from the 293 cell line exhibited a calcium-dependent elution profile on anion exchange chromatography, whereas only 25% to 35% of the hamster cell-derived rHPS exhibited this profile. However, the calcium-eluted rHPS from the AV12 cell line had a high specific cofactor activity, equivalent to that of the 293-derived rHPS. A NaCl- elutable rHPS fraction (calcium nondependent) was isolated from the recombinant AV12-664 cell line, further purified, and found to have reduced activity, only 40% that of the calcium-dependent rHPS. The only observable difference in the calcium-dependent and nondependent rHPS molecules was in the content of gamma-carboxyglutamic acid (Gla); the calcium-dependent material contained approximately 10 mol Gla/mol protein whereas the calcium-nondependent material contained only approximately 8 mol Gla/mol of protein. In addition, the calcium- nondependent rHPS had reduced ability to interact with phospholipid vesicles as evidenced by an eightfold increase in the apparent kd. Our data demonstrate the isolation of rHPS with high specific activity, and show that a reduction in as few as two Gla residues dramatically decreases its functional cofactor activity for HPC, due to a reduction in ability to interact with the phospholipid bilayer.     

Enhancement of erythrocyte superoxide dismutase activity: effects on cellular oxidant defense

To delineate further the role of superoxide dismutase (SOD) in red blood cell (RBC) oxidant defense, normal human erythrocytes were osmotically lysed and resealed in the presence of varying concentrations of exogenous SOD. This resulted in a dose-dependent increase in SOD activity in the resealed erythrocytes while maintaining nearly normal RBC hemoglobin concentration (less than 10% decrease from the control value), cell volume, and cellular deformability. Surprisingly, a five- or ninefold increase in SOD activity yielded no additional protection against superoxide-generating drugs (phenazine methosulfate or menadione sodium bisulfite). No significant differences were observed between the control and SOD-loaded RBCs in O2-driven methemoglobin formation or generation of thiobarbituric acid-reactive substances. In contrast, RBCs with elevated SOD activity pretreated with sodium azide (to block catalase activity) or 1-chloro-2,4- dinitrobenzene (to deplete reduced glutathione, GSH) showed significantly enhanced methemoglobin generation in response to superoxide generating drugs. No differential response was noted between the control, control-resealed, and SOD-loaded RBCs to oxidants other than superoxide. Based on our results and other data, we conclude that elevated SOD activity may imbalance cellular oxidant defense, resulting in enhanced oxidation due to the accelerated generation of H2O2, the product of O2- dismutation. This effect is significantly exacerbated under conditions in which H2O2 catabolism is altered.     

Infection of human T-cell leukemia virus type I and development of human T-cell leukemia lymphoma in patients with hematologic neoplasms: a possible linkage to blood transfusion

Among 354 adult patients with either hematological malignancy or aplastic anemia, eight were positive for anti-HTLV-I antibodies; six of eight had received multiple transfusions. There was an approximately 3.5-fold increase (P less than .001) of HTLV-I seropositivity in the patients with hematologic disease (8 of 354, 2.23%) compared to the healthy adults older than 20 years (34 of 5252, .65%). Two hematological patients, one with Hodgkin's disease and one with acute promyelocytic leukemia, were found to be positive for HTLV-I, and developed and died of adult T-cell leukemia/lymphoma (ATL) subsequently. Both were long-term survivors of the primary disease and had received multiple transfusions. The latent period from blood transfusion to onset of ATL was 6 months and 11 years, respectively. Immunocompromised patients, who were seropositive for HTLV-I, may be at increased risk for ATL compared to healthy carriers of HTLV-I, and the latent period may be shorter.     

Epidemiology and economic burden of viral hepatitis: an observational population based study.

OBJECTIVE: To describe the epidemiology and estimate the health resource use of patients with viral hepatitis in Tayside, Scotland, using record linkage techniques. DESIGN: A retrospective observational study. SETTING: Liver disease database, Tayside, Scotland. PATIENTS: All subjects resident in Tayside in the study period 1989-1999 and registered on the Epidemiology of Liver Disease in Tayside (ELDIT) database. MAIN OUTCOME MEASURES: Incidence and prevalence of known viral hepatitis in Tayside, survival of subjects diagnosed with viral hepatitis, and the health resource use with respect to hospital admissions compared with the general population. RESULTS: There were 4992 patients identified with viral hepatitis in the study period 1989-1999; 86 were IgM positive anti-hepatitis A, 187 patients were hepatitis B surface antigen (HBsAg) positive, and 469 were anti-hepatitis C (HCV) positive. HCV and HBsAg seropositive patients were more likely to be hospitalised and stay in hospital longer, less likely to survive after six years, and used more drugs of potential abuse than the general population. There was an increase in cost per admission and per patient as a consequence of liver disease. CONCLUSIONS: A record linkage population based study of viral hepatitis allows outcomes to be identified and costed. Those at risk of viral hepatitis infection in the Tayside population should be informed about the future implication to their health and costs to society. The health service should investigate the cost effectiveness of vaccination and opportunity costs to the health service of viral hepatitis taking into consideration the increasing incidence and prevalence of disease.     

Myocardial contractility and relaxation after deep hypothermic circulatory arrest in a neonatal piglet model

Cooling before circulatory arrest or ischemic arrest has been reported to influence myocardial performance in isolated neonatal hearts. The aim of the present study was to analyze indices of myocardial contractility and relaxation in an in vivo neonatal model after deep hypothermic circulatory arrest (DHCA). DHCA (18°C; DHCA group; n = 8) or mild hypothermic cardiopulmonary bypass ([MH-CPB] 32°C; MH-CPB group; n = 10) was applied in newborn piglets. After reperfusion (60 and 120 min), left ventricular dP/dt(max) increased in DHCA and MH-CPB, while-dP/dt(max) decreased slightly in DHCA and increased in MH-CPB. Nevertheless, the differences between the two groups did not reach statistical significance. In conclusion, left ventricular contractility remained stable after reperfusion following DHCA, to some degree at the expense of the diastolic function.     

Distribution of [14C]-ciprofloxacin in experimentally induced intramuscular abscesses of rats

Wistar rats were infected by injection of 0.05 ml of a dense oily suspension of Staphylococcus aureus into the posterior thigh muscles of the hind leg. Three days later, solid abscesses had formed which were characterized by a peripheral accumulation of polymorphocytes and incipient central necrosis. At this time, 10 mg/kg of [14C]-ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-piperazin-1-ylquino line-3-carboxylic acid, Bay o 9867; designated tradename: Ciprobay) were administered intravenously. The animals were sacrificed at various time intervals after treatment and the distribution of radioactivity was examined by whole-body autoradiography. Five min after administration of ciprofloxacin, the radioactivity was found to be differentially distributed among all organs and tissues, but no radioactivity was detectable in the abscess. Beginning from 1 h post appl., increasing relative amounts of radioactivity were seen inside the abscesses. The relative enrichment as compared to the surrounding muscle tissue was most pronounced after 5 h, indicating that the radioactivity was eliminated more rapidly from the muscle than from the abscess. Some radioactivity was still present in the abscess 8 h after treatment of the animals. The comparison of autoradiograms and corresponding histological sections revealed a distinct affinity of [14C]-ciprofloxacin and/or its potential radioactive metabolites to the areas of inflammatory cellular infiltrates.