Abstract: Clavulanic acid is a β‐lactamase inhibitor which prevents microbial lactamase inactivation of β‐lactam antibiotics. The pharmacokinetics and urinary excretion of clavulanic acid were studied in eight healthy adult volunteers after oral administration of 500 mg amoxicillin and 125 mg potassium clavulanate. Serum and urine clavulanic acid concentrations were assayed using high‐performance liquid chromatography. Pharmacokinetic parameters were: t1/2β = 1.019 ± 0.090 hour, t1/2α = 0.276 ± 0.031 hour, lag time = 0.321 ± 0.018 hour, tmax = 1.042 ± 0.80 hour, Cmax = 2.098 ± 0.441 μg/ml, and AUC = 4.897 ± 0.979 μg · hr/ml. Cumulative urinary excretion of clavulanic acid (as percentage of dose administered) was: 14.05 ± 2.87 within 2 hours, 25.77 ± 3.98 within 4 hours, and 27.85 ± 4.27 within 6 hours after administration.

Context Increasing evidence demonstrates that atherosclerosis is an immunologically mediated disease in which the secretion of atherogenic and atheroprotective cytokines, by infiltrating blood mononuclear cells, plays an important role. It is not known whether long-term exercise alters this atherogenic and atheroprotective activity directly. Objective To determine the effect of long-term exercise on the atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease. Design Before-after trial using a 6-month individualized, supervised exercise program, with an enrollment period from December 1996 to October 1997. Setting Hospital-based community wellness center. Participants of 110 persons who responded to a public request for volunteers, 52 met the inclusion criteria (risk ratio for myocardial infarction ≥1.7 based on serum complement and/or C-reactive protein levels, and normal exercise treadmill test results). Forty-three of the 52 enrollees (25 women [mean age, 49.7 years] and 18 men [mean age, 48.1 years]) completed the study; 9 withdrew for personal reasons. Additional risk factors for ischemic heart disease included hypercholesterolemia (65.1%), a family history of coronary heart disease (62.8%), inactivity (60.5%), hypertension (32.6%), obesity (25.6%), smoking (11.6%), and diabetes mellitus (4.7%). Main Outcome Measures Blood levels were compared at baseline and after the exercise program had been completed for the following: spontaneous and phytohemagglutinin-induced production of interleukin 1 α, tumor necrosis factor α, and interferon gamma (atherogenic cytokines), and interleukin 4, interleukin 10, and transforming growth factor beta 1 (atheroprotective cytokines) by blood mononuclear cells; lymphocyte phenotypes and mitogenic responses to phytohemagglutinin; and serum C- reactive protein levels. Results Subjects exercised for a mean of 2.5 (range, 0.3-7.4) hours per week. Mononuclear cell production of atherogenic cytokines fell by 58.3 % (P<.001) following the exercise program, whereas the production of atheroprotective cytokines rose by 35.9% (P<.001). Changes in transforming growth factor beta 1 and in phytohemagglutinin-induced atherogenic cytokine production after the exercise program were proportionate to the time subjects spent performing repetitive lower-body motion exercises (P<.02), indicating a dose-response relationship. After the exercise program, changes in cellular function were reflected systemically by a 35% decrease in serum levels of C-reactive protein (P = .12). Conclusions Our data suggest that long-term exercise decreases the atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease. This may be a mechanism whereby physical activity protects against ischemic heart disease.

No description available.

A microanalytical method with direct on-column specimen injection for determination of 1,3-butylene glycol (1,3-butanediol) in whole blood or plasma using gas-liquid chromatography with flame ionization is described. Whole blood or serum (minimum of 10 μL) was mixed with an equal volume of internal standard (1,2-propanediol, 50 mg/dL) and a 2-μL aliquot was injected onto the column without prior derivatization or extraction. The other short chain (C2 to C4) alkyldiols were separated by this method and did not interfere with the quantitation of 1,3-butylene glycol. The method was linear (y = 0.0206x + [-0.0073], r = 0.9990) over the range of 25 to 100 mg/dL and the coefficient of variation varied between 0.74 and 6.03%. Minimum detectable concentration of 1,3-butylene glycol was 5.0 mg/dL. The method described is suitable for the rapid detection of potentially toxic blood or plasma levels of 1,3-butylene glycol, as well as for the detection of other short chain glycols.

No description available.

The possible oxidative inactivation of buman blood plasma alpha-1-proteinase inhibitor (αl-Pl) by inhaled ozone was assessed. Eleven male volunteers (non-smokers) were exposed to 0.5 ppm ozone for four bours on two consecutive days and ten control subjects were exposed to air under the same conditions. Blood plasma samples, drawn before and after treatment, were assayed for total αl-PI, total protein and elastase inbibitory activity. The amount of active αl-PI in plasma samples was quanti-tated by titrating porcine pancreatic elastase with increasing amounts of plasma. The importance of constructing titration curves for determinations of this type was demonstrated. No differences were noted in the ratios of total α1-PI/total protein or elastase inhibitory activity/total αl-PI in the plasma from ozone exposed individuals relative to controls. Although inhaled ozone did not result in any significant decrease in the activity of blood plasma αl-PI, these findings do not preclude the possibility of oxidative inactivation of a αl-Pl in the lung.

The effects of treatment with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and vitamin E, an antioxidant, on immune functions were examined. Male C57/Bl mice were fed daily with natural vitamin E for 12 weeks, subsequently injected i.p. with MPTP or its vehicle, and sacrificed 1 week later. Control mice received the stripped corn oil vehicle daily, in place of vitamin E. Oral vitamin E feeding increased cerebral vitamin E content by 60% (P = 0.05). However, MPTP attenuated this rise in cerebral vitamin E content when measured 1 week after treatment with the neurotoxin (P = 0.05). MPTP also produced an 80 - 90% reduction in striatal dopamine content in both the stripped corn oil control group and the vitamin E-treated group (P = 0.0000). One week after MPTP injection, the numbers of peripheral blood lymphocytes and the percent of spleen T-cells, but not B-cells, were decreased in those groups receiving MPTP alone or MPTP plus vitamin E (P<0.05 and 0.02, respectively). The Con A-induced IL-2 production of spleen cells was decreased in all treated groups (P<0.005). There was no difference in the mitogenic stimulative response to PHA, Con A or LPS. However, the response to PWM was increased in both MPTP and MPTP plus vitamin E-treated groups (P<0.05 and 0.001, respectively). On the other hand, the one-way mixed lymphocyte response of the splenocytes from the MPTP-treated group was increased (P<0.01). These results indicate that MPTP exhibits an inhibitory effect on T-cells and modulates certain proliferative responses of immune cells, and that long-term intragastric administration of vitamin E exerts no measured protection against these acute toxicities produced by MPTP.

Flumazenil (FMZ, Flumazepil, Anexate, RO 15-1788) is an imidiazobenzodiazepine used in the reversal of benzodiazepine sedation and intoxication. Dosages of up to 1 mg reverse the coma and respiratory and CNS depression produced by benzodiazepines. Therapeutic dosages of FMZ produce plasma concentrations of up to 500 ng/mL. An analytical method was developed to determine FMZ concentrations in plasma and urine. Plasma and urine samples were spiked with FMZ from 5 to 500 ng/mL and flunitrazepam (FN, internal standard, 500 ng/ml). Specimens (3 ml) were extracted using 9 ml n-butyl chloride and 3 ml ammonium chloride buffer (pH 9.2). Extracts were dried under N2 in silanized glass, reconstituted in 25 μl methanol and 5 μl injected. GC/MS methodology utilized 15 m x 0.25 mm (ID) DB-5 (1.0 μm film) fused silica capillary column, with He carrier (29 cm/sec), splitless injection at 270°C, column 200-270°C @ 10°/min, separator oven 270°C, electron ionization (70 eV) with selective ion monitoring for FMZ (303 m/z) and FN (312 m/z). FMZ eluted at 7.37 min and FN at 8.19 min (relative index 0.8998). Correlation coefficients of concentration to peak area ratios were r = 0.9979 for plasma and r = 0.9943 for urine. Coefficients of variation were: plasma, 25 ng/ml, 13.2% (n = 5, x = 23 ± 1.3); plasma, 250 ng/ml, 6.6% (n = 6, x = 274 ± 7.4); urine, 25 ng/ml, 12.1% (n = 5, x = 23 ± 1.2); urine, 250 ng/ml, 10.7% (n = 5, x = 308 ± 14.7). This GC/MS method can determine FMZ concentrations in plasma and urine associated with therapeutic doses of FMZ.

Tryptases are trypsin-like enzymes found in mast cell granules that appear to exist as tetramers. These enzymes are not controlled by blood plasma proteinase inhibitors and only cleave a few physiological substrates in vitro, including high-molecular-mass kininogen (HMMK) and vasoactive intestinal peptide (VIP). Purified human lung mast cell tryptase (HLT) contained two bands of approx. molecular mass 29 and 33 kDa on SDS/PAGE. These two forms of HLT have been separated by chromatography on a cellulose phosphate column, with the high-molecular-mass form (high-HLT) being eluted with 10 μM heparin and the low-molecular-mass form (low-HLT) subsequently eluted with 1 M NaCl. Removal of asparagine-linked carbohydrate caused both isoforms to run as single sharp bands on SDS/PAGE, differing slightly in molecular mass. Separation of these two isoforms of tryptase shows that tetramers consist of four homologous subunits rather than mixtures of the two isoforms. Using HMMK and VIP as substrates, these two forms of HLT were found to differ with regard to specificity and rate of cleavage. High-HLT initially cleaved HMMK at Arg-431 within the C-terminal anionic binding region of the molecule, whereas low-HLT cleaved HMMK simultaneously at multiple sites within the C-terminal portion of the molecule. On the basis of HPLC peptide mapping, each isoform also cleaved VIP at different sites. Comparison of cleavage rates based on the active-site concentrations of titrated isoforms showed that low-HLT cleaved HMMK more rapidly than did high-HLT. These two isoforms may represent different gene products or they may result from post-translational modification.

Bronchial leucocyte proteinase inhibitor (BLPI) is an 11 000 M(r) protein found in human mucous secretions. This inhibitor apparently controls the serine proteinases elastase and cathepsin G, released from extravascular polymorphonuclear leucocytes. A simple, single-step chromatographic procedure for the isolation of BLPI based on its affinity for chymotrypsin was developed. The purified inhibitor was homogeneous by electrophoresis and gel filtration. Amino acid analyses were in close agreement with previous reports, and showed BLPI to be rich in proline and cystine, but lacking histidine. We have further characterized the role of BLPI with respect to human leucocyte elastase and cathepsin G by close examination of the kinetic parameters. Additionally, we have determined the kinetics of association (k(on)) and dissociation (k(off)) for BLPI with bovine trypsin and chymotrypsin. Equilibrium dissociation constants (K(i)) of 1.87 x 10-10M, 4.18 x 10-9M, 8.28 x 10-9M and 2.63 x 10-8M were obtained from human leucocyte elastase, cathepsin G, bovine trypsin and chymotrypsin, respectively. These results discussed with respect to BLPI's possible function in vivo and in its role relative to other inhibitors in bronchial secretions.