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Biomedical subjects

W Kirch

Publications and source records attributed to W Kirch.

At least 145 records · Page 8Linked to original sources
PubMed1994

Reflections on misdiagnosis.

It is correct to speak of misdiagnosis when, at the end of the diagnostic procedure, a disease which could not be proved by autopsy is assumed by the physician to be present; furthermore, when the non-recognition of the true disease leads to a worsening of the patient's prognosis. In contrast, the false positive and the false negative diagnoses have no prognostic relevance. The introduction of new diagnostic technology, such as sonography, scintigraphy and computer tomography, has not reduced the frequency of misdiagnosis appreciably within the last 20 years: now, just as before, its incidence appears to be about 10%. Over-reliance on the new procedures occasionally contributes directly to misdiagnosis.

Diagnostic Errors↗
PubMed1993

Changes in the effects of nizatidine and famotidine on cardiac performance after pretreatment with ranitidine.

This was an open, randomized study of the cardiovascular effects of the histamine H2 receptor antagonists ranitidine, famotidine, and nizatidine after single oral doses alone or in combination in healthy volunteers. When compared with placebo ranitidine (450 mg) did not have any haemodynamic effects. Nizatidine (300 mg) caused significant falls in heart rate and cardiac output. Famotidine (40 mg) caused significant falls in stroke volume and cardiac output and an increase in pre-ejection period. Pretreatment with ranitidine abolished the haemodynamic effects of nizatidine and caused a time-shift of 2 h in the onset of the cardiovascular effects of famotidine. The difference in the results for nizatidine and famotidine can be explained by the longer half-life of famotidine. Vascular effects are assumed to be responsible for impairment of cardiac performance by famotidine.

Adult↗
PubMed1993

Dose-dependent heart rate reducing effect of nizatidine, a histamine H2-receptor antagonist.

1. Twelve healthy subjects were treated in a randomised placebo-controlled crossover study with placebo, 150 mg, 300 mg, and 600 mg nizatidine, 100 mg pirenzepine, and 300 mg nizatidine plus 100 mg pirenzepine for 1 week each. 2. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, impedance cardiographic and Doppler ultrasound variables were measured. 3. Stroke volume and blood pressure were not altered by nizatidine and/or pirenzepine. By contrast, heart rate and cardiac output significantly (P < 0.05) decreased in a dose-dependent manner 1.5 and 3 h after administration of 300 and 600 mg nizatidine. Treatment with 150 mg nizatidine led to similar though non-significant trends. 4. While a slightly insignificant rise in heart rate was detected with pirenzepine alone, heart rate and cardiac output remained unchanged upon combined nizatidine and pirenzepine treatment as compared with placebo and baseline values. 5. In conclusion, nizatidine reduced heart rate and cardiac output in a dose-dependent manner, whereas this negative chronotropic effect was counteracted by concurrent administration of the anti-cholinergic drug pirenzepine.

Adult↗
PubMed1993

[The HLA pattern in Adamantiades-Behçet's disease in Germany. Association of occurrence, clinical symptoms and follow-up in 39 patients].

The frequencies of HLA-class I antigens were studied in 39 patients with Adamantiades-Behçet's disease and were compared with those in 1415 [corrected] healthy controls; both patients and controls were of German origin. Moreover, the correlations of HLA antigens with onset, various clinical features and the course of the disease were investigated and the familial clustering of the disease was examined. We found an increased frequency of the HLA-B5 antigen in these series (P < 0.05, relative risk 2.6, confidence interval 1.2-5.5). The presence of HLA-B5 was more frequently detected in male (41%, relative risk 4.9, confidence interval 1.8-13.1) than in female patients (9%; P < 0.05). A significantly higher frequency of HLA-B5 was found in male patients with severe vascular involvement, including blindness and thrombosis, than in HLA-B5-positive male patients without these features. Incidences of genital ulcers, ocular involvement, cutaneous features, positive pathergy test and of secondary symptoms as well as the age of onset and the duration of development of the complete clinical picture were all found not to be significantly correlated with any of the HLA-A, -B, -C alleles. Familial clustering was also not found in German patients. Because of the low relative risk in the presence of HLA-B5 and the lacking familial clustering, it seems likely that there is a weak immunogenetically determined predisposition for Adamantiades-Behçet's disease in Germany. HLA-B5-positive male persons of German origin show a higher relative risk to develop or acquire Adamantiades-Behçet's disease than female ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Erythema nodosum of dental origin.

The association of erythema nodosum and dental infectious foci has rarely been described in the literature. This report concerns four women who developed erythema nodosum either following dental treatment associated with gingival bleeding or due to infectious dental foci. In these cases, tooth extraction, removal of dental deposits, interrupted pulp treatment, apical periodontitis, or a relicted root were identified as causes of the development of erythema nodosum. Upon admission to the hospital, these patients also presented fever and and a maximally elevated erythrocyte sedimentation rate (ESR). In all instances, surgical treatment of the dental foci and/or administration of antibiotics rapidly led to the regression of the erythema nodosum, as well as to the normalization of body temperature and ESR. The cases described indicate that antecedent dental treatment and the possible presence of infectious dental foci should be considered in the differential diagnosis of erythema nodosum when taking the patient's medical history. This approach may avoid unnecessary, possibly invasive diagnostic procedures and can lead to rapid improvement in the patient's clinical status.

Adult↗
PubMed1992

Haemodynamic effects of roxatidine, an H2-receptor antagonist.

The haemodynamic effects of roxatidine were investigated in 12 patients with congestive heart failure (New York Heart Association class II) in a placebo-controlled, double-blind, randomized, cross-over study. Impedance and mechanocardiography were determined following successive 7-day treatment periods with placebo and roxatidine 150 mg once daily. Comparison with placebo values showed roxatidine to significantly increase the preejection period (109.7 +/- 2.7 ms versus 117.3 +/- 2.7 ms, 1.5 h after administration). Heart rate and blood pressure remained the same. In contrast to other, newer H2-receptor antagonists, which decrease stroke volume and/or cardiac output, roxatidine did not reduce these parameters but increased the preejection period and the ratio of the preejection period to the left ventricular ejection time, indicating a slight negative influence on cardiac performance.

Blood Pressure↗
PubMed1992

Divergent effects of different enzyme-inducing agents on endogenous and exogenous testosterone.

The effects of three different enzyme-inducing drugs (antipyrine 1200 mg, phenobarbital 100 mg, rifampicin 600 mg per day for 7 days) on plasma and urinary testosterone concentrations, plasma gonadotropin levels, antipyrine kinetics, and urinary 6 beta-hydroxycortisol excretion were studied in 18 healthy volunteers. Changes in plasma and urinary testosterone concentrations following exogenous testosterone undecanoate (TU) were also investigated. Although both antipyrine and rifampicin increased antipyrine clearance by about 60%, they produced contrary effects on testosterone: antipyrine lowered the total morning plasma testosterone and plasma testosterone AUC following TU, while rifampicin led to increases of about 20% and 78%, respectively. By contrast, phenobarbital did not significantly alter the endogenous and exogenous plasma testosterone concentrations, but it increased the urinary excretion of testosterone by more than 60%. The other two enzyme inducers did not alter this parameter. Gonadotropin levels remained unchanged. The results indicate that different enzyme-inducing agents exert divergent effects on endogenous and exogenous testosterone concentrations and suggest that the effect of enzyme induction on endogenous testosterone depends on the type of microsomal enzyme-inducing drug used rather than on the extent of the induction achieved.

Adult↗
PubMed1992

Stereoselective pharmacokinetics of oral nitrendipine in elderly hypertensive patients with normal and impaired renal function.

The pharmacokinetics of the enantiomers of nitrendipine has been studied in seven elderly patients with chronic renal failure (CRF) and in six control subjects (mean creatinine clearance 30 and 97 ml.min-1 respectively). Racemic nitrendipine 20 mg was given once daily for seven days and the pharmacokinetics of the enantiomers over the last dosage interval were determined using a stereospecific assay. In both groups nitrendipine exhibited stereoselective pharmacokinetics (AUC, Cmax), but the half-lives of the enantiomers did not differ in individual subjects. As an index of stereoselectivity, the mean S/R ratio of AUCs in control subjects (2.07) was not significantly different from the ratio in patients with CRF (2.68). The mean AUCs of (S)- and (R)-nitrendipine during the last dosage interval were increased in CRF by 132% and 85%, respectively. The observed doubling of the half-lives and the increases in Cmax did not reach significance because of the large variability in each group. Thus, the pharmacokinetics of oral nitrendipine is altered in CRF, but there was no change in the stereoselectivity of its pharmacokinetics.

Administration, Oral↗
PubMed1992

Influence of prolonged neuropsychological testing on immunoregulatory cells and hormonal parameters in patients with systemic lupus erythematosus.

The influence of a 2-h neuropsychological stress test on plasma catecholamines, cortisol, and on the distribution of lymphocyte subpopulations was studied in 14 patients with systemic lupus erythematosus (SLE), 10 patients on prednisone treatment (without collagenosis), and 14 sex-and-age-matched healthy controls. Psychological stress induced comparably significant increases in plasma adrenaline and noradrenaline levels as compared with baseline values (P less than 0.05) in all three groups, whereas plasma cortisol remained unchanged. The rise in plasma catecholamines was accompanied by a significant cell mobilization in healthy subjects and prednisone-treated patients, but not in patients with SLE. CD19+ cells increased significantly in number from baseline in healthy subjects and prednisone-treated controls (P less than 0.05), while remaining unchanged in SLE patients. In conclusion, SLE patients showed a reduced cell mobilization due to psychological stress despite hormonal alterations paralleling those of healthy subjects or prednisone-treated patients without collagenosis.

Adult↗
PubMed1992

Hemodynamic and humoral effects of the novel calcium antagonist Ro 40-5967 in patients with hypertension.

The tolerability and hemodynamic and humoral effects of the structurally novel calcium antagonist Ro 40-5967 were investigated in 64 patients with hypertension. In a double-blind, placebo-controlled study, ascending oral doses of 50, 100, 150, or 200 mg were administered once daily for 8 days in a solution. Ro 40-5967 was well tolerated up to 150 mg, but treatment was stopped in one patient in the 200 mg group because of bradycardia. Blood pressure was dose-dependently reduced over the full 24-hour dosing period with more pronounced effects on day 8 than on day 1. The maximum blood pressure reduction was obtained after 150 mg (supine blood pressure, -34/-25 mm Hg, p less than 0.001). Despite a slight decrease in supine heart rate, cardiac output increased. PQ time was dose-dependently increased and concentration-effect analysis showed that relevant atrioventricular conduction disturbances occur only at concentrations much higher than those required to reduce blood pressure. Changes in catecholamines, plasma renin activity, and aldosterone were small and inconsistent. In conclusion, Ro 40-5967 has a long-lasting antihypertensive effect after once-daily administration.

Aldosterone↗
PubMed1992

Hemodynamic effects of quinidine and famotidine in patients with congestive heart failure.

In a randomized, placebo-controlled, double-blind study, 12 patients with congestive heart failure (New York Heart Association class II) were successively treated for 1 week each with placebo, 40 mg famotidine, and 1000 mg quinidine. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, impedance cardiography, and Doppler ultrasound were measured. Heart rate and blood pressure were not markedly altered by either drug. By contrast, quinidine and famotidine significantly decreased stroke volume and cardiac output in impedance cardiography and Doppler ultrasound (p less than 0.05). A high correlation between both noninvasive methods was found for cardiac output and stroke volume (r = 0.93 and r = 0.97 for stroke volume 1 1/2 hours after quinidine and placebo administration, respectively). In addition, the mechanocardiographic ratio of the preejection period to the left ventricular ejection time in systolic time intervals increased significantly 1 1/2 and 3 hours after administration of quinidine and famotidine (p less than 0.05). In conclusion, both quinidine and famotidine exert similar negative effects on cardiac performance, with no significant differences in hemodynamic parameters emerging between the antiarrhythmic agent and the H2-receptor antagonist.

Cardiac Output↗
PubMed1992

Pharmacokinetics of temafloxacin in patients with liver impairment.

A multicentre study was conducted to determine whether liver impairment would alter the pharmacokinetics of temafloxacin, a new fluoroquinolone antimicrobial agent. 16 patients with cirrhosis and 12 healthy volunteers (the control group) received a single oral 600mg dose of temafloxacin. Blood and urine were sampled at frequent intervals after drug administration and assayed by high performance liquid chromatography. The mean age of patients with liver impairment was greater than that of the control group; they also had a lower creatinine clearance and urine output. There was no difference between the groups in either the peak plasma temafloxacin concentration or the time to reach peak concentration. However, the volume of distribution and elimination rate constant of temafloxacin were significantly lower in the group with liver impairment, as were total temafloxacin clearance, renal clearance, and the ratio of renal:creatinine clearance. Nonrenal clearance was similar in patients and controls. Creatinine clearance and urine output were found to account for most of the intersubject variability in total clearance as determined by multiple linear regression analysis. Because the altered temafloxacin pharmacokinetics appear to be primarily due to impaired renal function, this should be the main determinant of temafloxacin dosage in patients with liver disease.

Adult↗
PubMed1992

Effects of acute febrile infectious diseases on the oral pharmacokinetics and effects of nitrendipine enantiomers and of bisoprolol.

In 2 longitudinal studies with 10 patients each, the stereoselective pharmacokinetics of nitrendipine and the pharmacokinetics of racemic (rac) bisoprolol (both 20mg orally) were investigated during acute febrile infectious diseases and at least 6 weeks later in the healthy state. The area under the plasma concentration-time curve (AUC) and peak plasma concentration (Cmax) of rac-nitrendipine were increased in the infectious state by 89% [95% confidence interval (CI): 24 to 187%] and 95% (95% CI: 22 to 209%), respectively. Similar increases were observed for both S- and R-nitrendipine. Nitrendipine exhibited stereoselective pharmacokinetics in both the healthy state and the infectious state, but the mean ratios of S:R AUC values [healthy: 1.79 (95% CI: 1.36 to 2.11); infectious: 1.87 (95% CI: 1.62 to 2.11)] were not different. The elimination half-life, protein binding and haemodynamic effects of nitrendipine also did not differ between the infectious and the healthy state. The mechanism for the disease effects may be related to suppression of hepatic cytochrome P450 activity by mediators of inflammatory reactions. On the other hand, none of the pharmacokinetic parameters, including nonrenal clearance, of rac-bisoprolol was changed during febrile infectious disease, indicating specificity in the effects of acute febrile disease on oxidative drug metabolism.

Acute Disease↗
PubMed1992

Cardiovascular effects of omeprazole and famotidine.

In a randomized, placebo-controlled, double-blind, crossover comparison, 12 patients with congestive heart failure (New York Heart Association class II) and dyspeptic complaints were treated orally for 1 week each with placebo, 40 mg omeprazole daily, and 40 mg famotidine daily. Non-invasive haemodynamic measurements were taken on the last day of treatment. Although omeprazole did not alter cardiac performance in impedance cardiography and mechanocardiography, the administration of famotidine led to a significant fall in stroke volume and cardiac output as compared with placebo (both p less than 0.05). Thus, omeprazole did not exert any relevant cardiovascular effects, in contrast to the H2-receptor antagonist famotidine.

Aged↗