5-Lipoxygenase inhibitors: the synthesis and structure-activity relationships of a series of 1-phenyl-3-pyrazolidinones.

A series of analogues of the 5-lipoxygenase inhibitor 1-phenyl-3-pyrazolidinone (phenidone, 1a) has been prepared via two complementary new synthetic methods. The reaction of various electrophiles with the dianion of 1a or with an N-silylpyrazolidinone anion gave the desired 4-substituted pyrazolidinones (Scheme I and II). A new procedure was developed for the resolution of 4-substituted pyrazolidinones (Scheme V). A regression study on 21 compounds in this series showed a correlation of increased inhibitor potency (pIC50) with increased compound lipophilicity (log P) and with an N-phenyl electronic effect as measured by the 13C NMR chemical shift parameter CNMR1' (R2 = 0.79). The most potent 5-lipoxygenase inhibitor in this series was 4-(ethylthio)-1-phenyl-3-pyrazolidinone (1n) with an IC50 of 60 nM. Another member of this series, 4-(2-methoxyethyl)-1-phenyl-3-pyrazolidinone (1f, IC50 = 0.48 microM), although less potent than 1n, was better tolerated in the whole animal relative to phenidone (1a) and also displayed good oral activity in two models of 5-lipoxygenase inhibition. On the basis of a structure-activity relationship study, a mechanism for the inhibition of 5-lipoxygenase by this class of inhibitors was proposed.

Orally bioavailable benzisothiazolone inhibitors of human leukocyte elastase.

Human leukocyte elastase (HLE) has been proposed as a primary mediator of pulmonary emphysema and other inflammatory airway diseases. HLE is capable of cleaving many proteins, including elastin, other components of connective tissue, certain complement proteins, and receptors. Under normal conditions an appropriate balance exists in the lung between HLE and endogenous inhibitors, which scavenge the released enzyme before it exerts deleterious effects in the lung. Emphysema is thought to result from an imbalance in the lung between HLE and endogenous inhibitor (elevated elastase or insufficient inhibitor) that leads to the destruction of alveoli. We have identified WIN 64733 (2) and WIN 63759 (3) as potent (Ki* = 14 and 13 pM, respectively), selective, mechanism-based inhibitors of HLE which are orally bioavailable in the dog (absolute bioavailability 46% and 21%, respectively). In this series the in vitro stabilities of the inhibitors in blood, jejunal homogenates, and liver S9 homogenates are useful predictors of oral bioavailability. After being administered orally (30 mg/kg) to dogs, compounds 2 and 3 are found in the lung, being detected in the epithelial lining fluid obtained by bronchoalveolar lavage (Cmax of 2.5 and 0.47 microgram/mL, respectively).

Prevention of spinal cord injury after transient aortic clamping with tissue factor pathway inhibitor.

BACKGROUND: Lower limb paralysis that occurs in 11% of patients after treatment of thoracic and thoracoabdominal aortic aneurysms is unpredictable and at present not preventable. The proposed cause for the neurologic changes is believed to be spinal cord ischemia combined with ischemia/reperfusion injury. Recombinant tissue factor pathway inhibitor (rTFPI), a multivalent Kunitz-type inhibitor that binds to tissue factor-VIIa complex, was evaluated. METHODS: The effectiveness of rTFPI as an agent to limit spinal cord ischemia/reperfusion injury was studied in a rabbit spinal cord made ischemic for 20 minutes. rTFPI or phosphate-buffered saline solution (control) was given in randomized blinded fashion at the onset and conclusion of ischemia. Animals underwent neurologic evaluation at 24 hours in a blinded fashion with a modified Tarlov Scale to rate the lower limb paralysis (score of 4 = normal function, score of 0 = complete paralysis). RESULTS: Seventy-five percent of the TFPI-treated animals had Tarlov scores of 3 to 4, whereas only 29% of the animals treated with phosphate-buffered saline solution had such scores (p < 0.0014). Spinal cord histologic findings correlated with the neurologic findings. CONCLUSIONS: We believe that TFPI has unique inhibitory properties that make it an effective agent in limiting postoperative paraplegia associated with spinal ischemia.

Effects of exercise and physical fitness on the pituitary-thyroid axis and on prolactin secretion in male runners.

The effects of acute exercise and thyrotropin-releasing hormone on the pituitary-thyroid axis were examined in men placed into three well-defined categories of physical fitness. There were 20 sedentary men, 22 joggers (running four to 20 miles per week) and 18 marathoners (running 30 to 100 miles per week) who participated. During treadmill exercise, the mean VO2 max differed among all groups, being 38.5, 45.0, and 60.3 mL/kg . min in the sedentary, jogger, and marathon groups, respectively. Serum was obtained before, immediately after, and one hour after exercise for measurement of thyroxine (T4), triiodothyronine (T3), reverse T3, thyrotropin (TSH), and prolactin. Basal values of all hormones did not differ among the groups. Maximal short-term treadmill exercise produced no change in serum T4, T3, reverse T3, or TSH. Prolactin rose significantly by a similar amount in all three subject groups. On a separate day, ten individuals from each group received thyrotropin releasing hormone (TRH; 500 micrograms IV). Neither the peak TSH response nor the total TSH secreted during two hours after TRH differed among groups. The mean total prolactin secretion in the joggers and marathoners was 48% and 45% greater, respectively, than in the sedentary men. Five subjects in each group also underwent a TRH test immediately postexercise. Similar to the results on the nonexercise day, the integrated TSH response to TRH was similar in all three groups, whereas the integrated PRL response to TRH was increased by 52% and 78% in the two conditioned groups. Post-TRH sera from one subject in each group were fractionated on a Sephadex G-100 column.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of exercise and conditioning on clotting and fibrinolytic activity in men.

Sixty healthy men in three physical fitness categories (sedentary, on no organized fitness program; joggers, running 5-15 miles/wk; and marathoners, running greater than 50 miles/wk) were evaluated for changes in blood clotting and fibrinolytic activity before and after maximum exercise on a treadmill according to the Bruce protocol. The rate of blood clotting, as measured by prothrombin times, partial thromboplastin times and thrombin times, was accelerated by exercise (all P less than 0.005). The ability of euglobulin clots and plasma clots to lyse incorporated 125I-fibrin, termed 125I-euglobulin clot lysis (IEL) and 125I-plasma clot lysis (IPCL), were used as indexes of fibrinolytic activity. Marathoners had greater increases in fibrinolytic activity with exercise (76% compared with 63% for joggers and 55% for sedentary subjects by IEL; 427% compared with 418% for joggers and 309% for sedentary subjects by IPCL; all P less than 0.05). Fibrin degradation products increased with exercise (P less than 0.005 for the total group of 60 subjects). The absolute concentrations of alpha 2-plasmin inhibitor, alpha 2-macroglobulin, and antithrombin III increased with exercise (all P less than 0.005), but when concentrations were corrected for acute shifts of plasma water during exercise, the quantity of these inhibitors actually decreased (all P less than 0.005). The changes in clotting assays with exercise were not significantly correlated with changes in whole blood lactate, blood pyruvate, or rectal temperatures. Fibrinolytic assays before and after exercise correlated poorly to moderately with blood lactates (IEL: r = 0.441 and r = 0.425, respectively; IPCL: r = 0.294 and r = 0.544, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood viscosity responses to maximal exercise in endurance-trained and sedentary female subjects.

To assess whether the rheological properties of blood might be altered by exercise, we measured whole blood viscosity, plasma viscosity, and its components in healthy female subjects before, immediately after, and 1 h after maximal upright exercise using the Bruce graded exercise protocol. Forty-seven female subjects (15 sedentary, 14 who ran 5-15 miles/wk, and 18 who ran greater than 50 miles/wk), ages 18-43 yr, were evaluated. Whole blood viscosity, measured with a cone and plate viscometer, increased an average of 12.6% with exercise. The increase was greater than can be attributed to the observed 8.9% increase in hematocrit alone due to a coincident increase in plasma protein concentration. However, plasma viscosity did not rise to the degree expected, likely due to a disproportionate observed loss of fibrinogen from the protein pool. These changes were independent of conditioning level or aerobic capacity. In this cross-sectional study, there appears to be no adaptive adjustment in females to physical conditioning that results in changes in blood viscosity.

Plasma viscosity elevations with simulated weightlessness.

Bed rest studies which simulate weightlessness have demonstrated marked changes in the state of hydration of subjects as well as decrements in aerobic capacity. These two phenomena may be linked through increases in blood viscosity which is altered by a loss of free water and which, in turn, influences blood flow needed for aerobic muscular work. This study examines changes in the rheologic properties of blood which attend changes in plasma volume with bed rest in humans and correlates these changes with alterations in aerobic capacity. Eight healthy human subjects were studied on the 6th day of bed rest during two consecutive 10-d bed rest periods separated by a 14-d recovery interval designed to simulate the flight-layover schedule of shuttle astronauts. Plasma viscosity was measured with a Wells-Brookfield viscometer, plasma volume by dye dilution, and maximal aerobic capacity (VO2max) by recumbent cycle ergometry. Bed rest resulted in significant increases in hematocrit and in total plasma protein concentration and fibrinogen concentration, both of which contribute to an elevation in plasma viscosity. The greater than 20% increase in fibrinogen concentration was much greater than could be explained by hemoconcentration. VO2max decreased significantly in the first but not the second bed rest cycle. In many individuals, a decrease in plasma volume and aerobic capacity was coupled with elevated plasma viscosity and hematocrit; however, significant correlations between these variables were lacking. Although significant rheologic perturbations do occur with bed rest, in this study, blood viscosity elevation failed to directly correlate with the reduction in VO2max.(ABSTRACT TRUNCATED AT 250 WORDS)

Using quality service analysts to streamline record reviews.

By using registered nurse quality service analysts (RN-QSAs), the United States Air Force Medical Center in Wiesbaden, Germany, which closed in 1993, reduced physician reviews of medical records in 1991-1992 to only the records that did not meet the preestablished screening criteria. The authors relate how the screening of records by RN-QSAs increased the number of records reviewed, reduced the number of people reviewing records, established the quality services department as a repository of patient care information, and markedly improved the quantity, quality, and reproducibility of patient care reviews.

Survey of global telemedicine.

The number and scope of telemedicine projects and applications world-wide are growing rapidly along with exponential expansions in national and international information infrastructures and computer capabilities to support them. To track these rapid changes, the Center for Public Service Communications (CPSC) of Arlington, VA, developed the Telemedicine and Information Technologies in Health Care: Project Tracking Document for the National Aeronautics and Space Administration (NASA). This document is maintained by CPSC and frequently updated. It tracks the following areas in telemedicine and health care informatics: (1) major existing Federal grant and other assistance programs and activities; (2) legislation effecting policy in these areas; (3) projects using various technologies throughout the US; and (4) telemedicine projects/interests in other nations. This paper is a survey of international (global) telemedicine activities that are outlined in that document.

A re-examination of the cleavage of fibrinogen and fibrin by plasmin.

Three Fragment D species (D1, D2, D3) were isolated with time from a plasmin digest of fibrinogen and had molecular weights of 92,999, 86,000 and 82,000 by summation of subunit molecular weights from sodium dodecyl sulfate polyacrylamide gel electrophoresis. Their molecular weights by sedimentation equilibrium ultracentrifugation were 94,000 t87,000, 88,000 to 82, 000, and 76,000 to 70,000 depending on the values calculated for the partial specific volumes. Each of the Fragment D species contained three disulfide-linked subunits derived from the Aalpha, Bbeta, and gamma chains of fibrinogen and differed only in the extent of COOH-terminal degradation of their gamma chain derivatives. Plasmin cleaved Fragment D1 to release the cross-link sites from its gamma' subunit of 38,000 molecular weight; however, the beta'' subunit of 42,000 molecular weight and the alpha'' subunit of 12,000 molecular weight were resistant to further digestion by plasmin. Fragment D isolated from highly cross-linked fibrin had a dimeric structure due to cross-link formation between the gamma' subunits of two fibrinogen Fragment D species. The molecular weight of fibrin Fragment D was 184,000 by summation of subunit molecular weights and 190,000 to 175,000 by sedimentation equilibrium. Cross-linking the gamma chain, as well as incorporating the site-specific fluorescent label monodansyl cadaverine into the gamma chain cross-link acceptor site, prevented its COOH-terminal degradation by plasmin. Therefore, only one species of fibrin Fragment D, as well as only one species of monodansyl cadaverine-labeled fibrin Fragment D monomer, was generated during plasmin digestion. These results show unequivocally that each fibrinogen Fragment D contains only three subunit chains and therefore the digestion of fibrinogen by plasmin must result in the production of two Fragment D molecules from each fibrinogen molecule. The recently proposed model of fibrinogen cleavage that postulates the generation of a single Fragment D with three pairs of subunit chains from each fibrinogen molecule is incorrect. Incorporation of monodansyl cadaverine into the cross-link acceptor sites of the alpha chain did not alter its cleavage by plasmin detectably. A series of monodansyl cadaverine-labeled peptides, which ranged in molecular weight from 40,000 to 23,000, were cleaved from the alpha chain of monodansyl cadaverine-labeled fibrin monomer during the early stages of plasmin digestion. These peptides were degraded progressively to a brightly fluorescent plasmin-resistant peptide of 21,000 molecular weight and a weakly fluorescent peptide of 2,500 molecular weight. Thus both alpha chain cross-link acceptor sites are contained within a peptide segment of 23,000 molecular weight.

Pharmacologic characterization of immune complex induced bronchoconstriction in guinea pigs.

Intravenous injections of soluble immune complexes to anesthetized guinea pigs resulted in bronchoconstriction that was inhibited by FPL 55712, indomethacin, oxarbazole, soybean trypsin inhibitor, and cobra venom factor. Immune complex induced bronchoconstriction was not inhibited by atropine, imidazole, mepyramine, ketotifen, methysergide, and the anti-anaphylactic compound DPP (Diethyl [2-(4-pyridyl)-4-pyrimidinyl]aminoethylene malonate). Immune complex induced bronchoconstriction in guinea pigs appears to involve activation of complement and formation of anaphylatoxins. In addition, products of cyclo-oxygenase metabolism of arachidonic acid and kinins may be involved.

Fibrinogenolysis and fibrinolysis with strenuous exercise.

Twenty healthy young men were exercised on a treadmill according to the protocol of Balke and Ware. Mean duration of exercise was 24.9 +/- 5.7 min and mean maximum heart rate was 195 +/- 9. Fibrinolytic activity was markedly accelerated with euglobulin lysis times decreasing to 36% of control values and fibrinogen-fibrin degradation products increasing 109% after exercise. Assays for fibrin monomer were negative in all samples. In vivo fibrinogen A alpha-chin degradation was assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis of reduced samples of fibrin monomer isolated by clotting plasma samples in the presence of 0.1 M epsilon-aminocaproic acid and 1% disodium ethylenediaminetetraacetate. The A alpha-chain, the fibrinogen chain most susceptible to plasmin degeneration, showed no evidence of increased degeneration after exercise. Gel scans showed no decrease in the ratio of total alpha-chain to beta- and gamma-chains after exercise. The ratio of intact alpha 1 chain (alpha 1, 67,000 mol wt) to total alpha-chain was 0.66 +/- 0.13 before exercise, 0.64 +/- 0.14 immediately after exercise, and 0.65 +/- 0.13 1 h after exercise. The rate and extent of crosslinking of the alpha-chain of fibrin formed by clotting plasma samples was unaltered by exericse. These data suggest that physiologically significant fibrinogenolysis does not occur with strenuous exercise, even when fibrinolytic activity is markedly accelerated.

Beta receptors in peripheral mononuclear cells increase acutely during exercise.

Five healthy adult well trained men (averaging 49 miles running per week) were exercised to exhaustion on a treadmill. Plasma epinephrine increased from 168 +/- 37 pg/ml prior to exercise to 633 +/- 155 pg/ml immediately after exercise (P less than 0.025) and plasma norepinephrine increased from 1608 +/- 345 to 8576 +/- 1662 pg/ml (P less than 0.025) in the two respective periods. Beta receptor density increased from 53 +/- 18 fmol/mg protein before exercise, to 223 +/- 63 fmol/mg (P less than 0.05) protein immediately after exercise, and then decreased to 83 +/- 27 fmol/mg protein 1 h later (P less than 0.05 compared to post-exercise). The mean Kd value prior to exercise of 1.5 +/- 0.2 X 10(-11) M was unchanged statistically throughout the study. Following correction for haemodilution, serum total and free T4 and T3 concentrations were also unchanged during exercise, although reverse T3 levels did increase from 39 +/- 4 to 45 +/- 0 ng/dl (P less than 0.05). These findings suggest that: 1) plasma epinephrine, norepinephrine and beta receptor density, but not Kd, increase acutely during exercise and 2) total and free T4 and T3, after correction for haemodilution, do not change during acute exercise. Our data indicate that acute exercise represents an unusual condition during which 'down regulation' is not observed, but, rather, there appear to be parallel alterations in beta receptor density and plasma catecholamine levels.