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Biomedical subjects

M Wimmer

Publications and source records attributed to M Wimmer.

At least 73 records · Page 4Linked to original sources
PubMed1987

Effect of artemisinin (qinghaosu) and chloroquine on drug-sensitive and drug-resistant strains of Plasmodium falciparum malaria: use of [2,8-3H]adenosine as an alternative to [G-3H]hypoxanthine in the assessment of in vitro antimalarial activity.

Using [G-3H]hypoxanthine uptake as a radioactive indicator for the growth of malarial parasites, we measured the antimalarial activity of artemisinin (Qinghaosu, QHS) against FCMSU1/Sudan strain (chloroquine-sensitive strain) and FCB K+ strain (chloroquine-resistant strain) of Plasmodium falciparum in continuous culture in vitro. The 50% inhibitory concentrations (IC50) for QHS against FCMSU1/Sudan strain and FCB K+ strain were 2.8 X 10(-8) and 3.0 X 10(-8) M, respectively. On the contrary, the response of the two strains to chloroquine was quite different. The IC50 for chloroquine against FCMSU1/Sudan strain was 5.6 ng/ml, whereas that for the FCB K+ strain was 65.6 ng/ml. Therefore, QHS did not appear to exhibit any cross-resistance with chloroquine. If [2,8-3H]adenosine was used as a radioactive precursor instead of [G-3H]hypoxanthine for the determination of antimalarial activity, virtually identical results were obtained. Therefore, [2,8-3H]adenosine can be used as an alternative to [G-3H]hypoxanthine for the assessment of antimalarial action.

Adenosine↗
PubMed1987

Dysrhythmias following the Mustard and Senning operation for transposition of the great arteries.

The prevalence and nature of late dysrhythmias following operative repair of transposition of the great arteries were evaluated in 32 children using pre- and postoperative standard electrocardiograms and postoperative Holter monitoring. The Mustard procedure was performed in 17 patients, the Senning procedure in 15 patients. The mean age at operation was 40 +/- 35 months in the Mustard and 9 +/- 6 months in the Senning group. The mean interval between operation and Holter monitoring 7 +/- 2 years in the Mustard and 1.6 +/- 1 years in the Senning group. All patients had sinus rhythm preoperatively. Following operation, the incidence of sinus rhythm increased from 59% in the Mustard and 87% in the Senning group in the first postoperative week to 76% in the Mustard and 100% in the Senning group at the end of follow-up (mean 4.6 +/- 3.5 years). Holter monitoring revealed dysrhythmias or conduction abnormalities in 12 patients (9 Mustard, 3 Senning). A permanent pacemaker had to be inserted in 2 Mustard patients because of complete atrioventricular block and sinus bradycardia with sinus arrest, respectively. Results indicate a prevalence of late postoperative dysrhythmias of 20% in the Senning and of 59% in the Mustard group (p less than 0.05). However, the significantly longer mean follow-up period of the Mustard group precludes a direct comparison between the 2 types of repair.

Arrhythmias, Cardiac↗
PubMed1986

[Hemodynamic studies of nifedipine (Adalat) in pulmonary hypertension in childhood].

Under long-term oral treatment with nifedipine (N) 2 of 3 patients (2 children with VSD and Eisenmenger, 1 patient with Truncus I after corrective surgery) showed a remarkable improvement in exercise tolerance and reduction in the total pulmonary resistance. Therefore a single-dose testing with N was performed in 9 patients aged 2 to 20 years with primary pulmonary hypertension (n = 2), secondary pulmonary hypertension because of congenital heart disease with intracardiac shunts (n = 6) and after correction of Truncus Type I (n = 1). Before and after the injection of 0.5 mcg/kg of N into the main pulmonary artery, pulmonary artery pressure, cardiac output and systolic blood pressure were measured at 1 minute intervals during right heart catheterization. The maximal reaction occurred 3 to 4 minutes after the injection. The total pulmonary vascular resistance decreased significantly from 2684.2 +/- 1829.2 to 1300.2 +/- 1117.0 dyn.sec.cm-5.m2 (p less than 0.025), the cardiac index increased significantly from 3.1 +/- 1.65 to 5.73 +/- 1.95 l/min.m2 (p less than 0.01) concomitantly with a mild reduction in the mean pulmonary artery pressure. No significant change in heart rate and systolic blood pressure was seen; no side effects were observed. 4 of the 5 patients with the highest pulmonary vascular resistance showed the best positive reactions. Therefore these 9 patients may benefit from a long-term oral treatment with nifedipine.

Adolescent↗
PubMed1986

[Doppler echocardiographic evaluation of pressure in the pulmonary artery in children with congenital heart defects].

In children with congenital heart disease serial noninvasive assessment of the pulmonary vascular bed is desirable in order to determine the appropriate timing of cardiac catheterization and corrective surgery. To assess the value of pulmonary Doppler echocardiography for the estimation of pulmonary arterial pressure we correlated the rightsided systolic time intervals (preejection period, acceleration period, ejection period) derived from pulmonary artery Doppler traces with catheterization data (systolic, mean and diastolic pulmonary arterial pressure, total and vascular pulmonary resistances). 62 children aged from 1 month to 15 years suffering from congenital heart disease (n = 52), from rheumatic heart disease (n = 4), from cardiomyopathy (n = 5) or from primary pulmonary hypertension (n = 1) were investigated. The major finding was a highly significant correlation between the acceleration period and the systolic pulmonary arterial pressure (r = 0.79; p less than or equal to 0.0001). However the acceleration period could not be used for prediction of pulmonary arterial pressure in children with poor myocardial contractility.

Adolescent↗
PubMed1986

[Diagnosis of an aneurysm of the great cerebral vein of Galen using duplex sonography].

The combination of two-dimensional sonography of the skull and pulsed Doppler measurements (= Duplex-scan-technique) was used to detect an aneurysm of the vein of Galen in a three months old infant, who presented with clinical signs of congestive heart failure. Excellent correlation of sonography with computed tomography and intravenous digital subtraction angiography could be demonstrated. A short review of the pathological and clinical findings of this lesion is given. The value of Duplex-scanning in the diagnostic approach of arterio-venous malformations of the brain in comparison with other radiological methods is discussed.

Cerebral Veins↗
PubMed1985

The relation of rat liver wet weight to dry weight.

To assess a reliable relation between the dry and wet weight of rat livers, the water content of liver samples was determined by freeze drying. The ratio between wet and dry weight of the livers turned out as 3.33 +/- 0.3 for male and 3.28 +/- 0.24 for female rats. Thus for calculations a value of 3.3 can be used irrespective of the sex of rats.

Animals↗
PubMed1985

[Rare cause of a left ventricular aneurysm in a 10-year-old boy].

A 3-year-old boy had an accident with a blunt chest trauma, 9 years later a left ventricular aneurysm was diagnosed by echocardiography and angiography. The 12-year-old-boy was operated successfully. The pathogenesis of cardiac lesions in association with blunt chest traumas is described, and frequent control examinations in the affected patients are recommended.

Adolescent↗
PubMed1983

Antagonistic reaction of the periportal and perivenous zone in the rat liver after castration and estrogen treatment. Histochemical and biochemical studies on G6PDH and malic enzyme activity.

G6PDH and ME activity was determined biochemically in homogenates and demonstrated histochemically in cryostat sections of rat liver. Control animals were sham-operated, the male and female rats of the experimental groups were castrated. After castration groups of rats were treated with daily doses of 3 or 6 micrograms/estradiol benzoate for 21 days. The results show that in the controls there is a sex-dependent distribution pattern of the two enzymes; in males the rather low activity is mainly located in the periportal area, in females the higher activity is demonstrable in the perivenous area. After castration G6PDH activity (and to a lesser extent ME activity) increases, mainly in the periportal zone. Estrogen treatment results in the high activity of both enzymes, which are exclusively located in the perivenous zone. In the periportal zone no G6PDH or ME activity is demonstrable histochemically. This zone-typical effect of estrogen is interpreted in terms of the concept of Metabolic Zonation, according to which it is supposed that the NADPH generating enzymes in the perivenous area have a lipogenic function whereas the periportal activity contributes to bile acid production.

Animals↗
PubMed1983

[Idiopathic enlargement of the right atrium].

In a 3 year old male patient with a very rare congenital enlargement of the right atrium the diagnosis was made only because of an occasional chest X-ray film. These dilated right atria rarely cause symptoms, but in rhythmic disorders or thrombosis they can be life threatening. The differential diagnoses of this entity are listed.

Arrhythmias, Cardiac↗
PubMed1983

[Origin of the right pulmonary artery from the ascending aorta].

A 19-day old female infant presented with congestive cardiac failure. Cardiac catheterization and angiography demonstrated the right pulmonary artery to originate from the ascending aorta, and an atrial septal defect with a left to right shunt of 40%. At the age of six months anastomosis of the right pulmonary artery to the main pulmonary artery was performed with hypothermic arrest and cardioplegia. The postoperative course was complicated by respiratory distress but later the patient's condition improved. Four years later control cardiac catheterization and angiography visualized operative repair and only a small left to right shunt of 20% at atrial level.

Aorta↗
PubMed1982

[Mexiletine in the treatment of ventricular arrhythmias (author's transl)].

The indication and efficacy of mexiletine is described in five patients. In four children the first signs of arrhythmias were seen a short time after viral infection. Two girls had numerous ventricular extrasystoles, which showed very promptly a positive reaction to mexiletine. Two patients had ventricular tachycardias beside ventricular premature beats. Because of signs of cardial insufficiency a 13 year old boy was defibrillated before his cardiac rhythm could be established with mexiletine. Because of ventricular tachycardias the second patient was treated with a combination of mexiletine and propranolol. Seven years after corrective operation of tetralogy of Fallot a nine year old boy showed ventricular extrasystoles. Because of a very low plasma concentration of mexiletine the therapy was without any effect. In all children, a long term ECG over 24 hours was deduced. To control the efficacy of mexiletine in all patients the plasma-concentration was determined. The therapeutic effective plasma concentration of mexiletine lays between 0.5 and 2,5 mcg/ml. This level can be reached by a daily dose of 12.5--16.2 mg/kg body weight.

Arrhythmias, Cardiac↗
PubMed1982

[Prostaglandin E2 in newborns with congenital heart disease].

Prostaglandins of the E-type are potent ductus dilatators not only in vitro but also in vivo, as could be shown in the former literature. We report on 20 newborn children, in whom we only used prostaglandin E2 to perform a better lung or kidney perfusion by opening the ductus arteriosus. The diagnoses of the children were: pulmonary atresia + ventricular septal defect +/- transposition of the aorta, tricuspid atresia, hypoplastic left heart syndrome, transposition of the great arteries +/- ventricular septal defect, coarctation of the aorta and tetralogy of Fallot. The dosis pattern of the prostaglandin E2 infusion was in 17 patients the same, starting with 0.1 microgram/kg body weight/min and consecutive reduction depending on the capillary pO2, in the last 3 patients we started with 0.05 microgram/kg body weight/min. In 7 patients we gave an oral preparation of prostaglandin E2 intermittently. The duration of treatment was between 15 min and 37 days. There was a significant increase of the capillary pO2 under prostaglandin E2 treatment (p less than 0.0001), the increase of capillary pO2 correlates negatively with the initial pO2 before treatment (p less than 0.05), but there is no dependence on the age of the children. The side effects of this therapy are discussed, especially the dangerous apnoic spells.

Administration, Oral↗
PubMed1981

Hyperaldosteronism after heart surgery in children. Part II: Regulation of aldosterone secretion.

The relative importance of the various mechanisms responsible for development of postoperative hyperaldosteronism (HA) is not known. Therefore, serum sodium (NA), plasma-renin activity (PRA) and plasma cortisol (PC) were evaluated in pediatric patients with transient HA following heart surgery. PRA and PC were elevated and NA was depressed postoperatively. Plasma aldosterone (PA) was negatively correlated with NA (r = -0.77; p less than 0.001) and positively correlated with PRA (r = 0.68; p less than 0.01) but was not significantly correlated with PC. PRA and NA were significantly negatively correlated (r = 0.53; p less than 0.005). Multiple regression analysis revealed that NA had the strongest influence on PA, with PRA having a somewhat lesser but still significant influence; PC had no influence. Despite the significant negative correlation between PRA and NA, the interaction of the two variables in influencing PA was not significant (partial F-test; F = 0.12; p greater tha 0.5). It is concluded that in the postoperative state sodium depletion stimulates secretion of aldosterone not only via the angiotensin-renin system but also in a significant manner by a mechanism unrelated to the angiotensin-renin system. ACTH does not seem to play an important role in postoperative HA.

Adolescent↗