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Biomedical subjects

W Roth

Publications and source records attributed to W Roth.

At least 19 recordsLinked to original sources
PubMed1997

Immunochemotherapy of malignant glioma: synergistic activity of CD95 ligand and chemotherapeutics.

Malignant glioma cells are susceptible to CD95(Fas/APO-)-mediated apoptosis triggered by agonistic antibody. Here we examined the proapoptotic effects of the natural CD95 ligand, a cytotoxic cytokine homologous to tumor necrosis factor, on malignant glioma cell lines LN-229, LN-308 and T98G. We assessed whether glioma cell killing is synergistically enhanced by cotreatment with CD95 ligand and chemotherapeutic agents, including doxorubicin, carmustine, vincristine, etoposide, teniposide, 5-fluorouracil and cytarabine. Synergy was examined at low concentrations of cytotoxic drugs and CD95 ligand with a defined effect level (IC15). Short-term-cytotoxicity assays showed prominent killing of the glioma cells by CD95 ligand but not by the drugs at relevant concentrations. CD95 ligand induced apoptosis in the acute toxicity paradigm was augmented by doxorubicin and vincristine. Growth-inhibition assays revealed prominent synergy between CD95 ligand and all drugs examined. The best synergy was obtained with CD95 ligand and doxorubicin, vincristine or teniposide. The strong synergistic antiproliferative effects were observed at much lower concentrations of CD95 ligand and cytotoxic drugs than the moderate synergistic acute cytotoxic effects. All cell lines examined express the Bcl-2 protein. LN-229 has partial wild-type p53 activity. T98G has mutant p53, LN-308 has a deleted p53 gene and lacks p53 protein expression. Thus, synergistic effects of CD95 ligand and cytotoxic drugs were observed in cell lines exhibiting two features thought to play a role in the chemoresistance of human malignant glioma cells: loss of wild-type p53 activity and acquisition of bcl-2 expression. Ectopic expression of murine bcl-2 conferred partial protection from CD95 ligand and drugs when administered alone but did not interfere with the mechanisms underlying the synergistic effects of CD95 ligand and chemotherapeutic drugs.

Antineoplastic Agents↗
PubMed1997

The genes of the lysosomal cysteine proteinases cathepsin B, H, L, and S map to different mouse chromosomes.

The mouse genes for the lysosomal cysteine proteinases cathepsin B, H, L, and S were mapped to Chromosomes (Chrs) 14, 9, 13, and 3, respectively. Two of the DNA probes used in this study detected an additional, independently segregating locus. The cathepsin B-specific probe hybridized to a locus on Chr 2, and the cathepsin H probe to a locus on the X Chr. These loci either correspond to pseudogenes or to cathepsin B- and cathepsin H-related genes. The four cysteine proteinases mapped in this study lie within known regions of conserved synteny between mouse and human chromosomes, when compared with the corresponding positions of their human homologs. Assuming that the genes of the cysteine proteinase gene family arose from a common ancestral gene, our results suggest that these four cysteine proteinases had been dispersed over different chromosomes before separation of mouse and human in evolution.

Animals↗
PubMed1996

Attenuation of shock-induced inflammation in the rat liver depends on the time of TNF-alpha inhibition.

The relevance of tumor necrosis factor-alpha (TNF-alpha) inducing early inflammatory reactions in the liver after hemorrhagic shock, for example, leukocyte adhesion, has been well described. This study evaluated the anti-inflammatory effects of a monoclonal antibody against TNF-alpha (TN3.19.12) in terms of the time of application, namely, prior to shock induction, at the time of resuscitation, and after resuscitation. The hepatic microcirculation was investigated by intravital fluorescence microscopy in female Sprague-Dawley rats undergoing severe hemorrhagic shock for 60 min and subsequent resuscitation. TN3.19.12 or placebo was given in a randomized and blinded manner either 60 min prior to shock induction, 1 min prior to resuscitation, or 15 min after the onset of resuscitation. The number of firmly adherent leukocytes in the livers of treated animals depended on the time of application of TN3.19.12. Leukocyte adhesion was significantly reduced when TN3.19.12 was given prior to shock induction or at the time of resuscitation and was less effective when administered after the onset of resuscitation. The results further confirm that TNF-alpha initiates very early pathological leukocyte adhesion in the liver 5 h following shock. Inhibition of leukocyte adhesion after shock, however, depends strongly on the time of TNF-alpha blocking. While TN3.19.12 prior to shock induction resulted in most effective attenuation, only very early treatment allowed limitation of posttraumatically increased leukocyte adhesion.

Animals↗
PubMed1996

A review of the clinical pharmacokinetics of meloxicam.

Meloxicam is a new preferential cyclooxygenase-2 (COX-2) inhibitor currently for the treatment of osteoarthritis and rheumatoid arthritis. Its pharmacokinetic profile is characterized by a prolonged and almost complete absorption and the drug is > 99.5% bound to plasma proteins. Meloxicam is metabolized to four biologically inactive main metabolites, which are excreted in both urine and faeces. The elimination half-life (t1/2) of meloxicam is approximately 20 h. This is reflected in a total plasma clearance (CL) of 0.42-0.48 1/h. Steady-state plasma concentrations are achieved within 3-5 days. The pharmacokinetic parameters of meloxicam are linear over the dose range 7.5-30 mg and bioequivalence has been shown for a number of different formulations. No interactions were observed following the concomitant administration of food, cimetidine, antacid, aspirin, beta-acetyldigoxin, methotrexate, warfarin or furosemide. Neither hepatic insufficiency nor moderate renal dysfunction have any relevant effects on the pharmacokinetics of meloxicam and dosage adjustments in the elderly are not required.

Absorption↗
PubMed1995

Pharmacokinetic-pharmacodynamic and metabolite modeling with TopFit.

Two examples illustrating the ease of use and powerful data fitting and simulation techniques provided by the validated program TopFit 2.0 for the PC are presented. In the first, kinetics of parent compound and metabolite for (+) and (-) enantiomers of a racemic compound X were determined during a Phase III clinical study. Four data sets were fitted simultaneously for each patient. The model could be defined by the user without programming differential equations. The fit results indicated enantiomer specific kinetics for the metabolite but not for parent compound. In the second example, a model with nonlinear elimination and an Emax-effect function was used to simultaneously fit data from six doses of compound Y in a Phase I study. The fitted parameters predicted the feasibility of a twice-daily dose regimen despite a very short plasma half-life of the compound. In conclusion, TopFit provides rapid and cost-effective support in analysis and design of clinical trials.

Computer Simulation↗
PubMed1993

Zatebradine: pharmacokinetics of a novel heart-rate-lowering agent after intravenous infusion and oral administration to healthy subjects.

Zatebradine (1; UL-FS 49 CL; 1,3,4,5-[tetrahydro-7,8-dimethoxy-3-[3-[ [2-(3,4-dimethoxyphenyl)ethyl]methylamino]propyl]-2H-3-benzazepin- 2-on- hydrochloride) is the proposed INN name for a nonchiral, novel, specific heart-rate-lowering drug that is suitable for the treatment of stable angina pectoris. The pharmacokinetics of 1 and of total radioactivity in healthy volunteers (n = 6) were determined after intravenous infusion and oral administration of an experimental drug solution containing 7.5 mg (1.85 MBq) of 14C-labeled drug. Concentrations in plasma and urine were measured by a specific, sensitive, reversed-phase automated high-performance liquid chromatography system with fluorimetric detection at 285 nm Ex, 315 nm Em and by liquid scintillation counting. Recovery of total radioactivity was 89.8 +/- 2.3% (infusion) and 92.2 +/- 3.0% (oral). Renal elimination of total radioactivity was 62.5 +/- 2.0% (infusion) and 48.8 +/- 3.1% (oral). After intravenous infusion and oral administration, 27.3 +/- 2.4 and 43.4 +/- 3.9%, respectively, of the administered dose was eliminated in the feces. Absorption, based on renal excretion of total radioactivity following oral and intravenous dosing, was 79.2 +/- 15.3% (mean +/- standard deviation). Unchanged parent drug contributed 28.4 +/- 5.8% (infusion) and 12.4 +/- 3.7% (oral) of the dose to renal excretion. Zero to three minutes after cessation of the 20-min infusion, the maximum concentration of parent drug in plasma was 161.9 +/- 70.9 ng/mL. After oral administration, a mean peak concentration in plasma of 24.3 +/- 6.7 ng/mL (0.5-3 h postadministration) was reached. Data regarding levels of 1 in plasma could be adequately fitted with an open, two-compartment model.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

Force-time characteristics of the rowing stroke and corresponding physiological muscle adaptations.

The force-time characteristics of the rowing stroke was examined in a coxless pair. Sixteen highly trained rowers were evaluated in their usual training positions (stroke or bow). Stroke rowers had higher stroke speed and stroke force in the first part of the stroke than bow rowers. This finding was more prominent during competition speed rowing than during endurance training. Higher blood lactate levels and lower base excess were found at both speeds in stroke rowers. During and incremental ergometer rowing test, lactate performance curves were shifted to the left in the stroke rowers. Analysis of morphometric data in the left deltoid muscle demonstrated higher FT fiber content and lower oxidative fiber capacity and fiber areas in the stroke rowers. The results demonstrate adaptation to years of training in a specific boat position.

Adaptation, Physiological↗
PubMed1992

Clinical investigation of potency and onset of different lidocaine sprays for topical anesthesia in dentistry.

The clinical effects of three lidocaine-containing solutions with and without frigen (freon-113) as a propellant, after different waiting periods, and with different dosages applied were investigated in 130 outpatients who were undergoing dental treatment in the maxilla under local anesthesia. They were divided randomly into five groups (A through E): (A) Xylocaine spray with frigen, two applications (20 mg lidocaine); (B) Xylestesin spray with frigen, two applications (14 mg lidocaine); (C) Xylestesin spray with frigen, three applications (21 mg lidocaine); (D) Xylestesin pump spray without frigen, two applications (14 mg lidocaine); and (E) no topical anesthesia. They were further divided into 12 subgroups to evaluate waiting periods between the application of the topical anesthesia and the injection (1, 2, or 3 minutes). Patients assessed the pain of the injection, intensity of numbness, and intensity of the taste on a visual analog scale; they also assessed the pain of the injection compared to former injections. Pain during injection was reduced by topical application of lidocaine. A waiting period of 2 minutes proved to be sufficient and can be justified to avoid impatience and increased numbness in patients. However, a 3-minute waiting period may be appropriate for sensitive patients. An increase in the dosage failed to show better analgesia. The pump spray without frigen proved to be effective.

Aerosols↗
PubMed1992

Effects of different lidocaine sprays for topical anesthesia on cardiovascular parameters and oxygen saturation.

The effects of three lidocaine-containing solutions with and without frigen (freon-113) as a propellant on cardiovascular parameters and oxygen saturation, after different waiting periods and with different dosages applied, were investigated in 130 outpatients undergoing dental treatment in the maxilla under local anesthesia. They were divided randomly into five groups: (A) Xylocaine spray with frigen, two applications (20 mg lidocaine); (B) Xylestesin spray with frigen, two applications (14 mg lidocaine); (C) Xylestesin spray with frigen, three applications (21 mg lidocaine); (D) Xylestesin pump spray without frigen, two applications (14 mg lidocaine); and (E) no topical anesthesia. They were further divided into 12 subgroups to evaluate the influence of waiting periods between the application of the local anesthetic and the injection (1, 2, or 3 minutes). Without topical anesthesia and after the 1-minute waiting period, cardiovascular parameters increased immediately after the injection; after 2- and 3-minute waiting periods the increases were far less pronounced. The mean oxygen saturations did not change during the observed period. The higher lidocaine dosage administered (21 mg) did not intensify the positive impact on the cardiovascular parameters compared to the lower dosage (14 mg). The new pump spray without frigen proved to be as effective as the traditional, ecologically harmful aerosol sprays.

Adult↗
PubMed1991

Quantitation of the new hypoglycaemic agent AG-EE 388 ZW in human plasma by automated high-performance liquid chromatography with electrochemical detection.

A sensitive and selective high-performance liquid chromatographic assay has been developed for a new hypoglycaemic agent AG-EE 388 ZW (I) in human plasma. Plasma samples containing I were acidified with 0.2 M hydrochloric acid, directly injected into C2 reversed-phase pre-columns, and cleaned up on-line. After pre-column switching, the substance was separated isocratically in 15 min on a C18 reversed-phase column. Quantitation was performed after amperometric detection by external standard calibration curves. The linearity of the assay was demonstrated over the therapeutic concentration range 5-200 ng/ml. between-day coefficient of variation was 9.2% at 30 ng/ml. The limit of detection was 5 ng/ml in plasma. Determination of human plasma samples after intravenous and oral administration of 1 mg of 14C-labelled I demonstrated the applicability of the assay for pharmacokinetic studies in humans.

Administration, Oral↗
PubMed1991

Pharmacokinetic profile and tolerability of pimobendan in patients with terminal renal insufficiency.

The pharmacokinetics of an i.v. bolus of pimobendan (P) 2.5 mg and 5.0 mg, its tolerability and the effect on heart rate and blood pressure have been studied in 12 subjects (42-70 y) suffering from severe terminal renal impairment. Plasma level data were compared with those obtained in a previous investigation in healthy volunteers. Pharmacokinetics were dose linear and were comparable to those in healthy subjects. No adjustment of the dose of P is necessary in patients with severe renal impairment. Tolerability of P, observed by means of blood pressure monitoring, clinical chemistry tests, electrocardiography and subjective judgement resulted in 4 complaints out of 12 patients: three suffered from orthostatic problems and vomiting, and one patient had nausea. Mean heart rate was elevated by 19% (2.5 mg) and 16% (5.0 mg). Blood pressure was significantly reduced after 2.5 mg P (23% systolic and 26% diastolic pressure), and after 5.0 mg P by 25% systolic and 23% diastolic pressure.

Adult↗
PubMed1991

Combined haemoperfusion, haemofiltration and haemodialysis for systemic detoxification in locoregional 5-fluorouracil therapy.

Combined haemoperfusion, haemofiltration and haemodialysis (HPFD) was examined for its systemic effect on 5-fluorouracil (5-FU) kinetics after locoregional application to one female patient with liver metastases of a colon carcinoma. During each HPFD treatment, which lasted 4 h, 5-FU was given via a port-a-cath system into the hepatic artery on 4 separate days. The HPFD extraction rate was 99%. Extracorporal 5-FU clearance (89 ml/min) was 9% of total body clearance (1094 ml/min). The fraction eliminated within 4 h was only 6% of the applied dose (3500-4000 mg 5-FU). Sufficient extracorporal detoxification during combined HPFD can thus not be guaranteed in locoregional chemotherapy with a high dose of 5-FU.

Colonic Neoplasms↗
PubMed1990

Pharmacokinetics of falipamil after intravenous administration to humans.

Falipamil (2-[3-[3-(3,4-dimethoxyphenetylmethylamino]propyl]-5,6- dimethoxyphthalamidine; 1) is a new specific bradycardic agent for the treatment of sinus tachycardia. Pharmacokinetics of falipamil in humans (n = 6) was determined in plasma and urine after iv administration of 100 mg (1.85 MBq) per person of 14C-labeled drug by liquid scintillation counting and by a specific, sensitive reversed-phase totally automated HPLC system with fluorimetric detection. Recovery of total radioactivity was 91.8 +/- 3.7%, with 68.2 +/- 4.3% in urine and 23.6 +/- 2.5% in the feces. The majority of radioactivity was excreted within 24 to 48 h. The parent drug, falipamil (1), and its N-desmethyl-metabolite (2), which is approximately 100 times less active than 1, contributed 14.1 +/- 1.6 and 4.5 +/- 0.7%, respectively, of the dose to urinary excretion. Plasma protein binding of 1 and 2 was 87.9 +/- 1.2 (concentration range: 2000-8000 ng/mL) and 89.7 +/- 0.5% (concentration range: 62.5-1000 ng/mL), respectively. Plasma concentrations of 1 peaked at 2 min at 724 +/- 173 ng/mL, declined biphasically, and were fitted to a two-compartment open model. Plasma concentrations of 2 were very low, in all cases ranging from 0 to 35 ng/mL. The dominant terminal half-life (beta-phase) of 1 from plasma was 1.8 +/- 0.6 h (range 1.4-2.9 h), mean residence time was 2.4 +/- 0.4 h, total body clearance was 1108.5 +/- 119 mL/min, and renal clearance was 117 +/- 20 mL/min. All parameters demonstrated very low intersubject variability.

Adult↗
PubMed1989

Cardiovascular effects and plasma level profile of pimobendan (UD-CG 115 BS) and its metabolite UD-CG 212 in patients with congestive heart failure after single and repeated oral dosing.

Pimobendan (10 mg on day 1, then 5 mg twice daily for 28 days) was administered orally to nine patients in class III-IV stable congestive heart failure. On day 1, pimobendan appeared in plasma within 30 min, its plasma concentration peaked at 39 +/- 23 ng/ml after 1.5 h, and then decreased with a half-life of 1.44 +/- 0.94 h. Concentrations of its major metabolite UD-CG 212 peaked 3 h after drug intake, at 24 +/- 7 ng/ml. The time course of plasma concentrations was similar on days 1, 2, and 28. Cardiac index increased from 2.2 +/- 0.5 to 2.8 +/- 0.4 L.min-1.m-2 (p = 0.0001) on day 1, from 2.8 +/- 0.5 to 3.4 +/- 0.4 L.min-1.m-2 (p = 0.0032) on day 2, and stayed at 2.7 +/- 0.6 and 2.7 +/- 0.9 L.min-1.m-2 (p = 0.7895) on day 28. On day 1, pulmonary capillary wedge pressure decreased from 16 +/- 7 to 6 +/- 5 mm Hg (p = 0.0001), from 10 +/- 7 to 7 +/- 8 mm Hg (p = 0.0001) on day 2, and from 9 +/- 7 to 5 +/- 3 mm Hg (p = 0.0275) on day 28. Cardiovascular effects of pimobendan were independent of plasma concentrations. All patients improved by at least one NYHA functional class; exercise tolerance increased. No side effect was observed, but two patients died suddenly: Arrhythmogenicity should be ruled out before pimobendan is recommended for treatment of heart failure.

Aged↗
PubMed1989

Correlations between the cardiovascular effects of pimobendan and plasma concentrations of the parent compound and of its major active metabolite, UD-CG 212 CL, in patients with congestive heart failure.

Pimobendan was administered orally (10 mg single dose on day 1, then 5 mg twice daily for 4 weeks) to nine patients with chronic heart failure undergoing hemodynamic monitoring. The time course of changes in plasma concentrations of pimobendan and of its major active metabolite. UD-CG 212 CL, was similar on days 1, 2, and 28. Pimobendan plasma levels peaked 1.5-2.0 h after drug intake: plasma concentrations of UD-CG 212 CL reached a maximum 1 h later; the terminal half-life of pimobendan in plasma varied between 1.44 +/- 0.94 h on day 1 and 1.19 +/- 0.36 h on day 2. Initially, cardiovascular variables changed with increasing plasma drug levels and reached a maximum 4 h after pimobendan intake; later, we found no correlation between plasma concentrations and hemodynamic effects. A steady state of hemodynamic improvement was achieved after 4 weeks of maintenance therapy with pimobendan. Baseline pulmonary capillary wedge pressure dropped from 16 +/- 7 mm Hg on day 1 to 5 +/- 3 mm Hg at noon on day 28 (-69%; p less than 0.001), and baseline cardiac index increased from 2.2 +/- 0.5 L/min/m2 on day 1 to 2.7 +/- 0.9 L/min/m2 on day 28 (+23%; p less than 0.01). Pimobendan is a long-acting drug that effectively improves cardiac performance in patients with chronic congestive heart failure.

Administration, Oral↗