Computerized management of oral anticoagulant therapy: experience in major joint arthroplasty.

OBJECTIVE: Evaluation of the safety and potential cost savings of a computerized, laboratory-based program to manage inpatient warfarin thromboprophylaxis after major joint arthroplasty. DESIGN: A consecutive-case study of adults. SETTING: A tertiary care orthopedic institution. PATIENTS: Patients requiring joint arthroplasty who had no recent episodes of thromboembolic disease, no mechanical heart valve, atrial fibrillation, severe liver disease or baseline international normalized ratio [INR] greater than 1.3 admitted over a 54-month period (July 1994-December 1998). All patients received a standard regimen of warfarin beginning on the evening after the operation. Four hundred and thirty randomly selected patients managed by the program were followed up by telephone survey 3 months after discharge. Patients exhibiting erratic responses to warfarin were withdrawn from the program and managed individually thereafter. INTERVENTION: Major joint arthroplasty with warfarin therapy administered through the computerized program. MAIN OUTCOME MEASURES: Test results maintained within the desired therapeutic range (INR 2.0-3.0), clinically severe bleeding episodes, readmission rates, clinically symptomatic and venographically proven episodes of venous thrombosis or pulmonary embolism. RESULTS: Over the study period 5629 patients underwent joint arthroplasty; 5,372 patients were considered for the program; 332 patients were ineligible and were managed individually; 311 entered patients did not complete the program. This left 4,729 patients who completed the program. In 2932 (62%) patients test results were maintained in the desired therapeutic range. The major bleeding rate was less than 0.5%, the readmission rate was 3.8%, the deep venous thrombosis rate was 3.7% and the pulmonary embolism rate was 0.2% with no thromboembolic related deaths in the small sample cohort. CONCLUSIONS: The majority of patients requiring warfarin thromboprophylaxis can be safely and effectively managed by this laboratory-based computerized program while in hospital. Significant potential cost savings in nursing time could be achieved.     

Effect of tetrahydrouridine and deoxytetrahydrouridine on the interaction between 2'-deoxycytidine and 1-beta-D-arabinofuranosylcytosine in human leukemia cells

The interaction between 2'-deoxycytidine (dCyd) and 1-beta-D-arabinofuranosylcytosine (ara-C), administered at pharmacologically achievable concentrations, was examined in four continuously cultured human leukemia cell lines, HL-60, KG-1, K-562, and CCRF-CEM. In three of the cell lines (HL-60, K-562, and CCRF-CEM), co-administration of 20 or 50 microM dCyd with 10 microM ara-C reduced ara-CTP formation by at least 90% and incorporation of ara-C into DNA by at least 80%. In contrast, KG-1 cells exhibited substantially smaller reductions in both ara-CTP formation and incorporation of ara-C into DNA under identical conditions. KG-1 cells were distinguished by the highest activity of the enzyme cytidine deaminase of the four lines assayed, and exhibited the smallest increments in the intracellular accumulation of both dCyd and deoxycytidine triphosphate (dCTP) in response to exogenous dCyd. Co-administration of 1 mM tetrahydrouridine (THU) or 0.5 mM deoxy-tetrahydrouridine (dTHU) had little effect on the ability of dCyd to antagonize ara-C metabolism in HL-60, KG-1 and K-562 cells. In contrast, these deaminase inhibitors substantially increased the intracellular accumulation of dCTP as well as the ability of dCyd to antagonize ara-CTP formation and incorporation of ara-C into DNA in KG-1 cells. THU and dTHU also permitted dCyd to antagonize ara-C growth inhibitory effects in KG-1 cells to the extent observed in the other leukemic cell lines. These studies suggest that the intracellular deamination of exogenous deoxycytidine may influence the degree to which this nucleoside antagonizes ara-C metabolism and toxicity in some leukemic cells. They also raise the possibility that deaminase inhibitors may be employed to modulate, and perhaps to improve, the therapeutic selectivity of pharmacologically relevant concentrations of ara-C and dCyd in the treatment of acute leukemia in man.     

Airway permeability in rats exposed to ozone or treated with cytoskeleton-destabilizing drugs

Ozone (O3) exposure of rats increases airway epithelial permeability. We hypothesized that this increased permeability may be mediated by the epithelial cell cytoskeleton. To test this hypothesis, we studied the effect of cytoskeletal disruption on the transmucosal transport of tracers from airway lumen to blood and compared the results with the effects of O3 exposure. No increase in transport occurred following disruption of microtubules by vinblastine, but disruption of microfilaments with cytochalasin D resulted in increased transport of radiolabeled tracers [99mTc- and 111In-labeled diethylenetriamine-pentacetate (DTPA) and 125I-labeled bovine serum albumin (BSA)]. In control rats, both horseradish peroxidase (HRP) and BSA, localized by cytochemistry and autoradiography, respectively, were detected on the epithelial cell surfaces and in endocytic vesicles. In rats treated with cytochalasin D or exposed to O3, the tracer molecules also penetrated the intercellular spaces, though the apical tight junctions remained devoid of the tracers. Increased numbers of endocytic vesicles containing HRP and aggregation of 125I-labeled BSA autoradiographic grains in the subepithelial region were also seen after either treatment. We conclude that destabilization of cytoskeletal elements following O3 exposure is a possible mechanism of increased transmucosal transport, which may be a combined effect of accelerated transport through both endocytic and paracellular pathways.     

Attenuation of ozone-induced airway permeability in rats by pretreatment with cyclophosphamide, FPL 55712, and indomethacin.

Exposure of rats to ozone (O3) produces an increase in airway permeability and a concomitant influx of polymorphonuclear leukocytes in the lung. These observations raise the possibility that the inflammatory cells play a role in the cellular injury and increased airway permeability after O3 exposure. This study was therefore designed to determine if the inflammatory cells or their products are essential for the O3 effect. In a series of experiments, rats were rendered leukopenic with cyclophosphamide, treated with leukotriene B4 (LTB4), or with the inhibitors of lipoxygenase or cyclooxygenase products of arachidonic acid, followed by exposure to O3. A 2-h exposure to 0.8 ppm O3 caused a significant increase in the flux of proteins and albumin in bronchoalveolar lavage (BAL) and elevated the transport of 99mTc-diethylenetriaminepentaacetate (99mTc-DTPA) from trachea to blood. The treatment with cyclophosphamide caused a significant reduction in the circulating and pulmonary leukocytes and prevented an increase in tracheal mucosal permeability to 99mTc-DTPA and the protein and albumin flux in BAL. While the intratracheal instillation of LTB4 did not affect the permeability, tracheal permeability and albumin levels in BAL in rats treated with LTD4 antagonist FPL 55712 and exposed to O3 were lower than in the untreated O3-exposed rats. Pretreatment with indomethacin also prevented the O3 effects, as reflected by the decreased protein and albumin flux in BAL and 99mTc-DTPA transport from trachea to blood. These data show a reduction in the effect of O3 by agents that affect leukocytes or their products. The results support a mechanism of increased permeability that is dependent upon inflammatory cells and their products.     

Newer indolyl imidazolones as anti-inflammatory agents

Sixteen new 1,2-disubstituted-4-(indol-3'-yl)methylene imidazol-5-ones were synthesized by the condensation of oxazolone with different aryl amines and evaluated as to their anti-inflammatory and antiproteolytic activities. These derivatives showed 2-38% protection against carrageenin-induced paw oedema in albino rats at a dose of 100 mg/kg p.o. All compounds showed antiproteolytic activity. The degree of inhibition against trypsin-induced hydrolysis of casein ranged from 10 to 75% at a concentration of 4 X 10(-4) mol/l. Furthermore, active compounds of the series were also screened for their analgesic activity against aconitine-induced writhing in albino mice. The toxicity of the compounds was reflected by their approximate LD50 values.     

Estrogen receptor-alpha gene transfer into bovine aortic endothelial cells induces eNOS gene expression and inhibits cell migration

OBJECTIVES: It has been suggested that estrogen may improve endothelial cell function to delay the onset of atherosclerosis in pre-menopausal females, though its mechanism of action is not fully understood. We examined the hypothesis that human estrogen receptor-alpha (ER alpha) gene transfection improves the endothelial cell function. METHODS: A replication deficient adenoviral vector was used to transfect the ER alpha gene into bovine aortic endothelial cells (BAEC) and a GFP gene containing vector was used as control. Expression of the eNOS gene was determined by Northern blot analysis and enzyme activity assay; cell migration was assayed using a Transwell apparatus; and tyrosine phosphorylation of FAK was estimated by Western blot analysis. RESULTS: ER alpha gene transfection of endothelial cells produced a 2-3-fold increase in eNOS mRNA and protein levels as well as a significant increase (P < 0.05) in NOS activity as measured by citrulline assay and nitrite accumulation in the media in response to bradykinin stimulation. Treatment of cells with estrogen blocking agent ICI 182780 inhibited eNOS induction in response to ER alpha transfection. ER alpha gene transfection significantly inhibited (P < 0.05) bFGF-induced chemotactic migration of endothelial cells but increased cell attachment to fibronectin, laminin, and type I and IV collagens. ER alpha gene transfer also inhibited bFGF-stimulated tyrosine phosphorylation of FAK. CONCLUSION: Our results suggest that the atheroprotective effects of estrogen may in part be mediated by ER alpha-induced upregulation of eNOS gene expression and maintenance of endothelial cell function and integrity.