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Biomedical subjects

D Pfeiffer

Publications and source records attributed to D Pfeiffer.

At least 145 records · Page 8Linked to original sources
PubMed1990

[Treatment of tachyarrhythmia in a patient with long QT syndrome by autologous heart transplantation and atrial stimulation controlled by the sinoatrial node].

The authors described an operation performed in a female patient aged 37 years who was first examined in 1980. That year she experienced the first ventricular fibrillation episode. The duration of the Q-T interval was 600 msec. She was examined by a comprehensive protocol which enabled coronary abnormalities to be excluded. The operation was made in July 1987 in the Charite Hospital by Dr. Warnke. The operation involved dissection of the nerve connections nearest the heart by cutting the pulmonary artery, aorta, both atria and subsequently suturing by the scheme used in cardiac grafting. The patient rapidly recovered after the surgery. She had a normal Q-T interval and no recurrences of ventricular tachycardias. Following the surgery she displayed disturbances of intraatrial conduction and pacemaker displacement into the lower segments of the right atrium, so she was implanted a DDD-mode pacemaker.

Adult↗
PubMed1989

Long QT syndrome associated with inflammatory degeneration of the stellate ganglia.

A well-studied case of intermittent long QT syndrome in a 21-year-old female is presented. Electrophysiologic investigation repeated three times revealed changing sinoatrial and atrioventricular dysfunction and nonsustained ventricular tachycardia. The patient died 29 months after first hospitalization in a stage of electromechanical dissociation after runs of torsade de pointes although she had been treated with repeated anti-inflammatory therapy as well as high doses of propranolol. Postmortem examination demonstrated active inflammation of stellate ganglia. Myocardium appeared normal.

Adult↗
PubMed1989

Clinical implications of the epidermal growth factor receptor in the squamous cell carcinoma of the uterine cervix.

The clinical implications of the epidermal growth factor (EGF) and its receptor (EGF-R) were studied in 52 squamous cell carcinomas of the uterine cervix. In comparison to 40 biopsies of the normal cervix EGF-R capacity was significantly increased in the carcinomas, while the affinity was unchanged. The amount of EGF-like substances extracted from the tumors was increased in patients with lymph node metastases, in whom 5-year survival is reduced. Irrespective of tumor stage patients with a very high level of EGF-R (greater than 100 fmole/mg protein) were more likely to have recurrences later or to die from disease: recurrence or death occurred in 5 of 7 patients with high capacity and in 2 of 45 patients with low capacity. Our data suggest that the level of EGF-R is indicative of the biological aggressiveness of cervical carcinomas.

Adult↗
PubMed1989

Human corticotropin-releasing hormone during pregnancy.

Elevated irCRH levels up to 14 ng/ml were measured in 176 females in the last trimester. The highest maternal CRH levels were found in those females in whom the period from the onset of labour to full dilatation of the cervix and the time span of delivery were shortest. irCRH in amniotic fluid (120 +/- 180 pg/ml; n = 14) was in the same range as in umbilical cord plasma (233 +/- 188 pg/ml; n = 66) and 20-fold lower than in prepartal maternal plasma (5.38 +/- 4.49 ng/ml; n = 66). irCRH in maternal plasma correlated highly to irCRH in umbilical cord plasma (p less than 0.001; n = 66). After delivery irCRH disappeared from maternal plasma with a half-life of 50 minutes (n = 14). One day postpartum irCRH levels (n = 22) were undetectable. The height of the irCRH levels in the various biological fluids did not correlate to the mode or the pathological events of delivery (n = 43). Maternal ACTH levels above the normal range were encountered only in women immediately prepartal and did not correlate to the CRH levels (253 +/- 229 pg/ml; n = 66). Cortisol levels were higher in maternal plasma than in umbilical cord plasma due to elevated CBG (n = 78). Free cortisol levels were higher in the 3rd trimester than in the 1st (2.18 +/- 0.16 vs 1.16 +/- 0.73 ng/ml; n = 42). irCRH in maternal and umbilical cord plasma correlated to the hPl and estriol levels (p less than 0.001 and p less than 0.05; n = 66). We conclude that irCRH is secreted by the placenta into both maternal and fetal circulation. Though placental CRH is undistinguishable from hypothalamic CRH, the biological significance of placental CRH remains open. Our data show that placental CRH might be responsible for the changed function of the adrenal gland during pregnancy, with higher free cortisol levels in the last trimester. The extremely elevated ACTH levels during labour and delivery indicate that CRH is not the only mediator of stress-induced ACTH secretion in the regulation of the maternal hypothalamo-pituitary-adrenal axis.

Adolescent↗
PubMed1989

Glucose measurement in diluted blood.

The sensitivity, measuring range and lifetime of enzyme electrodes using glucose oxidase sandwiched between dialysis membranes or alternatively in a polyurethane layer directly on the surface of a platinum electrode are compared. The GOD modified electrode exhibits the highest sensitivity. However, the signal depends strongly on the stirring rate. Using the sandwich membranes up to 120 diluted blood samples per hour with a serial coefficient of variation below 1% can be analyzed.

Biosensing Techniques↗
PubMed1987

[Arrhythmogenic effects of anti-arrhythmia agents].

Arrhythmogenic effects appear in 5-22% of all patients. On the basis of a literary investigation on 11,547 patients with 1,114 proarrhythmic effects and of 21 own observations mechanisms, risks and diagnostics of this dangerous side effect are demonstrated. In most cases patients with severe functional disturbances of the heart and known ventricular tachyarrhythmias are affected. Not infrequently a prolonged QT-internal is found. An accumulation of the known arrhythmias or an appearance of new disturbed rhythms, frequently Torsade de pointes, may occur. Holter-ECG and programmed stimulation are suited for recognition, which are together to be applied in malignant tachyarrhythmias. The prophylaxis deals with a careful indication, aimed selection of the antiarrhythmic drugs and a subtile control of therapy in the first days after the beginning of the therapy and after every increase of dosage.

Adult↗
PubMed1987

[Transvascular intracardiac ablation--on the current status of the method in the treatment of tachyarrhythmias].

A survey is given on the method of the transvasal intracardiac ablation in the treatment of atrial and ventricular tachyarrhythmias. Experimental fundaments, indication, method and possible complications are reported. Own results on five patients with His bundle ablation are described. A possible further development of the method is the enlargement of the His bundle ablation to the ablation of focal arrhythmias, Kent's fibres and ventricular tachycardias without evocation of a total atrioventricular block. Alternative techniques of the cauterization, the laser ablation and the high frequency coagulation are described.

Adult↗
PubMed1987

Metabolism of exogenous 4- and 2-hydroxyestradiol in the human male.

The metabolic fate of the isomeric catecholestrogens 4-hydroxyestradiol (4-OHE2) and 2-hydroxyestradiol (2-OHE2) was studied to elucidate possible differences in their metabolism as an explanation for their different bioactivities. Healthy young men (n = 3 each) were infused (90 min) with 4-OHE2 (60 micrograms/h) or 2-OHE2 (100 micrograms/h). The main metabolites were determined in plasma and urine before, during and after infusion. Unconjugated and conjugated steroids, the latter after hot acid hydrolysis, were subjected to chromatography on LH-20 columns and measured by specific RIAs. During the infusion 4-OHE2 reached significant plasma concentrations whereas 2-OHE2 was so rapidly metabolised that its plasma levels remained virtually undetectable in spite of a higher infusion rate. The metabolism of 4-OHE2 was dominated by direct conjugation, that of 2-OHE2 by methyl ether formation. These findings were corroborated by the urinary excretion rates: during the infusion and the first hours afterwards, 4-OHE2 was mainly excreted as 4-OHE2 and 4-hydroxyestrone, while 2-OHE2 was predominantly excreted as 2-hydroxyestradiol 2-methyl ether and 2-hydroxyestrone 2-methyl ether.

Adult↗
PubMed1986

[Differential therapeutic problems in sinus node syndrome--drug or electrical therapy?].

121 hospitalised patients with electrophysiologically ascertained sick sinus syndrome were ambulatorily observed for two and a half years. The knowledge of the electrophysiological parameters allowed in every case an exact estimation of the degree of severity. Patients with preponderantly isolated disturbance of the sino-atrial node automatism, the sino-atrial conduction and the nervous regulation (patients with carotid sinus syndrome) as well as the majority of patients with bradycardia-tachycardia-syndrome were conservatively treated. Patients with high-degree combined disturbances of the sinus node partial functions were electrically treated. Every cardiac syncope in the medicamentously treated sick sinus node syndrome is the absolute indication for a pacemaker implantation. The further observation in the outpatient department showed that in many patients with symptomatic sick sinus node syndrome an attempt of conservative treatment is justified.

Anti-Arrhythmia Agents↗
PubMed1986

Anterograde conduction of a concealed accessory pathway after transvenous electric catheter ablation.

An 18-year-old woman with a concealed right midseptal accessory pathway and refractory supraventricular tachycardia with a cycle length of 280-400 ms and a wide echo zone of 280-520 ms is reported. The transvenous electric catheter ablation with two shocks of 200 and 300 J, each on a separate occasion, was followed by anterograde and retrograde atrioventricular block. The patient received an implantable pacemaker (VVI). Four weeks later we observed a stable anterograde conduction of the pathway in spite of a persisting retrograde block. It is concluded that the site of unidirectional block in this patient is at the origin of the concealed accessory pathway in the ventricular septal muscle. The necrosis after ablation changed conduction conditions at the site of unidirectional block. Presently, the patient has been free of tachycardia for 19 months. This observation is of importance for the patient because another mechanism of tachycardia might be possible after ablation.

Adolescent↗
PubMed1986

Inhibition by auranofin of pharmacologic and antigen-induced contractions of the isolated guinea pig trachea.

The effects of an orally active gold complex, auranofin, were investigated on the isolated guinea pig trachea contracted pharmacologically and antigenically. Pretreatment of the tracheal tissues for 15 minutes with auranofin (10(-5) and 10(-4) mol/L) produced a significant rightward shift of a histamine dose-response curve (p less than 0.001), whereas a 30-minute pretreatment with auranofin (10(-4) mol/L) inhibited LTD4-induced (but not LTC4-induced) contraction of the tracheal spirals. In tracheas from animals actively sensitized to ovalbumin, auranofin (10(-4) mol/L) significantly inhibited contractions elicited by 0.01 micrograms/ml of this antigen. Auranofin does not appear to behave like a nonspecific suppressant of tracheal muscle contraction since it failed to antagonize a potassium chloride-induced (6 X 10(-2) mol/L) contraction. Therefore, auranofin appears to alter the in vitro response of the guinea pig trachea not only to histamine but also, more importantly, to LTD4 and specific antigen. These results characterize and extend further the pharmacology of auranofin in airway tissue.

Animals↗
PubMed1985

[Clinico-electrophysiologic studies on the action of the anti-arrhythmic substance 3-carbethoxyamino-5-dimethylamino-acetyl-10,11-dihydro-5H- dibenz[b,f]azepine hydrochloride (Bonnecor, AWD 19-166, GS 015)].

The effects of the new antiarrhythmic drug 3-carbethoxy-amino-5-dimethyl-amino-acetyl-iminodibenzyl-hydroc hlorid (Bonnecor) (B.) were investigated by means of clinical-electrophysiologic methods (His-bundle electrography, programmed electrical stimulation) in 11 patients with normal cardiac output and paroxysmal supraventricular tachycardias. In a maximal dosage of 0.24 mg/kg body mass. B. affects several compartments of the impulse initiation and conduction. B. has positive chronotropic actions on the sinus node automaticity, negative dromotropic effects on the sinu-atrial, intraatrial, AV nodal and intraventricular conduction and finally negative bathmotropic actions on the myocardium of the atria and ventricles. B. suppress the artificial induction of paroxysmal supraventricular tachycardias in patients with AV nodal reentry. These results help to recognize indications (supraventricular and ventricular premature beats or tachycardias) and contraindications (sick sinus syndrome, atrio-ventricular block of higher degreé and bifascicular blocks).

Adult↗