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Biomedical subjects

E Hoffmann

Publications and source records attributed to E Hoffmann.

At least 163 records · Page 9Linked to original sources
PubMed1992

Efficacy of automatic multimodal device therapy for ventricular tachyarrhythmias as delivered by a new implantable pacing cardioverter-defibrillator. Results of a European multicenter study of 102 implants.

BACKGROUND: Third-generation implantable cardioverter-defibrillators are devices designed to treat ventricular tachycardia (VT) and ventricular fibrillation (VF) by means of overdrive pacing, cardioversion, or defibrillation. So far, the efficacy of tiered therapy has been documented only in small series. Therefore, a European multicenter clinical evaluation study of a new tachyarrhythmia control device, the Medtronic PCD pacer-cardioverter-defibrillator with epicardial patch-lead configuration, was undertaken. METHODS AND RESULTS: We report on 102 patients (mean age, 55 +/- 13 years) from 11 European centers. PCD devices implanted between May 1989 and February 1991 were included. The patients suffered from hemodynamically significant ventricular tachyarrhythmias not suppressed by antiarrhythmic drug therapy and unrelated to acute myocardial infarction; one patient had nonsustained VT and severely depressed left ventricular function. Seventy patients had coronary artery disease with old myocardial infarctions, 23 had cardiomyopathies of various etiologies, and nine patients had no detectable heart disease. Mean ejection fraction was 36 +/- 14% (range, 10-76%). Mean intraoperative defibrillation threshold (51 patients) was 10.6 +/- 5.1 J (range, 2-18 J). The documented follow-up ranged from 1 to 21 months (mean, 9.4 +/- 5.8 months), or 79.9 cumulative patient-years. Perioperative mortality was 3.9%. The actuarial survival rate at 12 months was 91%. One sudden arrhythmic death occurred. Sixty patients (58%) received device therapy. Seventeen patients had therapies only for "VF" episodes, 16 patients only for VT, and 28 patients for VT and "VF" episodes. Based on device memory data, 1,235 spontaneous VT episodes were detected and treated in 43 patients. Twelve hundred four of these VT episodes received painless initial antitachycardia pacing therapy, restoring sinus rhythm in 91%. The 108 ongoing episodes received 209 multiple therapeutic attempts. Eighty-five additional overdrive pacing therapies restored sinus rhythm in 30%. Initial ineffective antitachycardia pacing therapies received 51 cardioversion pulses. The success rate was 61%. Seventy-three additional cardioversion pulses were delivered to backup ineffective pacing therapy as well as ineffective secondary cardioversion pulses. Their success rate was only 40%. Two hundred eighty-six spontaneous episodes were detected in 44 patients as "VF." Overall defibrillation efficacy was 97.6%. CONCLUSIONS: The implanted device nearly eliminates sudden arrhythmic death in patients with documented, potentially fatal ventricular tachyarrhythmias. Automatic tiered therapy is highly effective to restore sinus rhythm, provided that an integrated two-zone tachycardia detection algorithm is used, assigning lower tachycardia rates to overdrive pacing and/or cardioversion and higher tachycardia rates to defibrillation. In general, spontaneous VTs can be terminated by automatic overdrive pacing, and painful or disturbing countershock therapies are not required to terminate the majority of spontaneous VT episodes.

Death, Sudden, Cardiac↗
PubMed1992

[Importance of physical parameters for the effectiveness of radiofrequency catheter ablation].

Radiofrequency catheter ablation has been shown to be an effective form of treatment of accessory pathways in patients with WPW-syndrome and other supraventricular tachycardias. However, the biophysical parameters so far used in vivo neither correlated with the size of the myocardial lesion nor did they provide any information about contact of the electrode with the myocardial wall. In this study, 104 radiofrequency energy applications were performed on excised pig myocardium in circulating heparinized pig blood, and in blood alone, and root mean square (rms) voltage, current and phase angle were measured using a specially developed device. The calculated effective power and output power differed by only 2-7% measured at the point of maximum current during coagulation. A progressive drop in current following a rise in impedance led to a phase shift of more than 80 degrees with a decrease in effective power to 17% of the output power. Hence, apparent output power was mainly ineffective power. The time-dependent variations of phase angle, impedance and current were found to be useful for distinguishing between the coagulated media. These results show that physical parameters measured during radio-frequency catheter ablation may help to monitor electrode position in the clinical situation and reduce the number of ineffective energy applications.

Animals↗
PubMed1992

[Anti-arrhythmia and pro-arrhythmia effects of oral cibenzoline therapy in sustained ventricular tachycardia].

The efficacy and safety of the new class-I antiarrhythmic drug cibenzoline was assessed in 12 patients with spontaneous and inducible ventricular tachycardia. Programmed ventricular stimulation, 24-h ambulatory electrocardiogram (ECG), and continuous ECG monitoring were performed without antiarrhythmic drugs and after oral administration of 254 +/- 80 mg of the substance. Oral cibenzoline suppressed the induction of tachycardia in only one patient. Induction of tachycardia was more difficult in two patients, unchanged in four patients, and easier in two patients. Cycle length of induced tachycardia and QT-interval corrected for frequency were not changed significantly; effective refractory period of the right ventricle was prolonged. Twenty-four hours of ambulatory monitoring during cibenzoline treatment (n = 9) showed no significant increase in the frequency of ventricular premature complexes. However, spontaneous sustained ventricular tachycardia developed in three patients after initiation of cibenzoline treatment. In two patients, termination of induced ventricular tachycardia was significantly more difficult under cibenzoline; several DC-shocks were required to terminate the tachycardia. Thus, the use of oral cibenzoline in patients with sustained spontaneous and inducible ventricular tachycardias showed a low antiarrhythmic efficacy at programmed stimulation and a high incidence of spontaneous ventricular tachycardia.

Adult↗
PubMed1992

[Left ventricular catheter ablation of the AV conduction system with radiofrequency electric current].

We report on a 32-year-old female patient with a history of recurrent atrial fibrillation and rapid ventricular response (up to 240 beats/min) resistant to multiple drug therapy. In this patient, we successfully performed a radiofrequency catheter ablation of the atrioventricular (AV) junction from the left ventricle, after radiofrequency energy application in His-position above the tricuspid valve was unsuccessful. This technique offers an-alternative treatment in patients in whom the conventional right-sided catheter ablation of the AV junction proves ineffective.

Adult↗
PubMed1991

Kinetic parameters of enzymatic reactions in states of maximal activity; an evolutionary approach.

A theoretical investigation is presented which allows the calculation of states of maximal reaction rates for single enzymes and for unbranched enzymatic chains. As an extension to previous papers (Heinrich & Holzhütter, 1985, Biomed. biochim. Acta 44, 959-969; Heinrich et al., 1987, Bull. math. Biol. 49, 539-595) a detailed enzymatic mechanism was taken into consideration. Conclusions are drawn for the optimal values of the microscopic rate constants as well as of the maximal activities and Michaelis constants. Ten solutions are found which depend on the equilibrium constant as well as on the concentrations of substrates and products. It is shown that for high equilibrium constants one of the solutions applies to a very large range of the concentrations of the outer reactants. This solution is characterized by maximal values of the rate constants of all forward reactions and by non-maximal values of the rate constants of all backward reactions. In contrast to previous assumptions (Albery & Knowles, 1976b, Biochemistry 15, 5631-5640; Burbaum et al., 1989, Biochemistry 28, 9293-9305) states of maximal reaction rate are not always characterized by the highest possible values of the second-order rate constants which are related to the diffusion of the substrate and the product to the active site of the enzyme. Predictions are made concerning the ratios of maximal activities in optimal states as well as for the adaptation of the Michaelis constants to the concentrations of the outer reactants. Using metabolic control analysis it is shown that the solutions obtained for single enzymes may also be applied in multi-enzyme systems.

Animals↗
PubMed1991

[Diabetic ketoacidosis (169 episodes in 131 patients in the course of 10 years)].

Diabetic patient material--presenting hyperglycaemic ketoacidotic episode--observed in Gyula and Szekszárd County Hospitals in period 1980-89, was reviewed by authors. 131 patients were admitted with 169 ketoacidotic episodes (among them 23 patients had 62 recurrences). The mean age of patients were 49.4 years (14-84 years), duration of diabetes 9.5 years (from one month to 45 years). The common cause of diabetic ketoacidosis was respiratory (26 per cent) and enteral (35.5 per cent) infection. The consciousness of patients had shown close correlation with the increase of blood sugar and urea nitrogen level as well as with the decreasing of the pH value of capillary blood. The first step of the therapy was the parenteral fluid intake with isotonic solution (in the first hour the average 1351 ml). In 18 patients fast-acting insulin (Novo Actrapid MC) was given by constant infusion, in the remaining cases intravenous or intramuscular low doses of the same insulin were administered. The importance of early potassium replacement, and the dangers of forced and rapid correction of acidosis is emphasized. Lethality related to episodes was 10 per cent, related to the patients 12.9 per cent. The number of ketoacidotic cases did not decrease parallel with the improvement of therapeutic possibilities, as it was experienced by their earlier evaluations. The importance of the prevention of acute metabolic disorders is outlined might be resulted from increasing the efficacy of patients education and better knowledge of GP's, as well.

Adolescent↗
PubMed1991

[Possibilities of early diagnosis of autonomic neuropathy in diabetics].

The possibilities of the diagnosis of autonomous neuropathy were investigated by the authors in 71 insulin-treated diabetes mellitus patients with the use of dynamic esophageal scintigraphy and determination of cardiac reflex tests. It has been found that the extent and severity of the lesion can be earlier and more exactly recognized with the help of these two methods. Important information can be obtained by the determination of esophageal transit time about the functional condition of vagal nerves supplying gastrointestinal organs. In patients suffering from autonomous neuropathy the esophageal transit time proved to be significantly prolonged (p less than 0.01). The injury of parasympathetic heart innervation is earlier indicated by the pulmo-cardiac reflexes, while the troubles of symphathic functions are shown more responsively by the sustained handgrip test. Cases with considerable degree of orthostatic hypotension were not observed, its incidence may be probably higher only in advanced forms of autonomous neuropathy. The injury of vegetative nerve fibers develops mostly parallel in diabetes mellitus, but partial functional disorders can be also observed. Detailed neurological examinations were performed in 30 patients, and it has been found, that the lesion of peripheral nerves can be only later observed. Specific complications involving the nervous system are more frequent in cases with longer duration of the disease. In the authors opinion, for investigation and follow-up of larger number of diabetic patients, the dynamic esophageal scintigraphy and determination of pulmo-cardiac reflex and sustained handgrip tests seem to be suitable.

Adult↗
PubMed1991

A new phloroglucinol derivative from Hypericum calycinum with antifungal and in vitro antimalarial activity.

The new phloroglucinol derivative 1 has been isolated from the light petroleum ether extract of the aerial parts of Hypericum calycinum. Its structure has been established by means of 1H- and 13C-NMR spectroscopy and by nOe, MHQC, and HMBC experiments on its monomethyl ether derivative 3. Compound 1 was fungicidal against Cladosporium cucumerinum in a TLC bioassay. In addition, this new phloroglucinol derivative was also found to exert an interesting antimalarial activity in an in vitro test system.

Animals↗
PubMed1991

Clinical nursing research priorities: a Delphi study.

Using the delphi technique, a group of clinical nurse specialists was surveyed regarding delineation of clinical nursing research priorities. Upon completion of the four-round survey, the results suggested that the top priorities for nursing research are: (1) factors which influence longevity in clinical nursing practice, (2) patient care delivery systems as related to nurse satisfaction, and (3) indicators of quality nursing care.

Attitude of Health Personnel↗
PubMed1991

Urinary excretion of CGS 5,649 and its conjugated glucuronide and sulfate in man.

Experiments in animals have indicated that CGS 5,649 B [6-(2-isopropylaminopropyl)-3-pyridinol fumarate] might enhance memory and learning processes and might be a valuable drug for treatment of impairment of vigilance and mental performance in the elderly. CGS 5,649 (I) is extensively metabolized. Therefore, we investigated the excretion of the drug and its conjugates (I-SULF,I-GLUC) into urine after oral administration of 1200 mg of the fumarate salt of I to one healthy male volunteer. Three HPLC methods were developed to analyze the three compounds in urine: a. Solid-phase extraction and UV-measurement at 280 nm; b. Dansylation followed by fluorometric detection (lambda ex 340, lambda em 525 nm); c. Direct injection of diluted urine, gradient system with ion-pair reagent and UV-detection at 280 nm. The conjugates were measured after enzymatic hydrolysis with glucuronidase/sulfatase and sulfatase. I-GLUC was also measured directly since a synthetic sample had become available. Results from the different analytical methods showed agreement: about 100% of the administered dose was excreted within 24 h; the relative amounts of I, I-SULF and I-GLUC were about 1:2:2; after oral administration, CGS 5,649 B is rapidly and completely absorbed; it is eliminated from plasma by conjugation and direct excretion into urine.

Chromatography, High Pressure Liquid↗
PubMed1990

[Prognostic factors affecting survival in multiple myeloma].

70 patients suffering from multiple myeloma were observed by authors in the last 15 years and three months. In the meantime fifty-two out of them have died, and 18 patients are under permanent care. 43 IgG, 17 IgA, 6 Bence-Jones, 2 IgD types were diagnosed according to the paraprotein distribution, one patient proved to be nonsecretory, and an other one to osteosclerotic form as well. The median survival time was 27 months in the group of deceased patients. In the group followed-up 50.8 months survival time was observed up to the closing of the study. Several prognostic factors were investigated. According to the classification by Durie and Salmon the survival time was 60 months in the patients with stage I, 33 months in stage II., and 9 months in stage III respectively. The prognosis is much poorer in patients into the "B" category: the survival time was 14 months. Classified in the basis of the type of the myeloma-cell, the cases with well matured cells have had the best prognosis with survival time of 46 months, while the most unfavourable prognosis was observed in patients with blast-cell type, with a median survival time of 10 months. The greatest number of patients suffered from multiple myeloma of IgG paraprotein type, in this group the serum IgA level was found to be significantly decreased in the patients died due to inevitable infections. The survival was injured significantly by the occurrence of concomitant severe diseases, to.(ABSTRACT TRUNCATED AT 250 WORDS)

Bence Jones Protein↗
PubMed1990

[Extra-pleural approaches in the management of bronchial stump insufficiency following pneumonectomy].

Insufficiency of the bronchial stump is still a dreaded complication. The treatment with the use of extrapleural accesses led to a significant improvement of the therapeutical results. We have to distinguish between transpericardial techniques and the contralateral thoracotomy with transpleural or extrapleural access. If the pleural cavity is still sterile, immediate or four week postoperative insufficiency may be treated using rethoracotomy with resuturing the stump. Coverage of the stump with pedicled muscle tissue provides a rather good method for a secondary treatment of the bronchial stump. When the pleural cavity is already infected, extrapleural treatment of the bronchial stump should be undertaken immediately. In addition, all late insufficiencies are treated extrapleurally. If only a very small opening of a fistula is found, an endoscopical closure of the fistula should be attempted using acryl glue or fibrin glue. Our own therapeutic results concerning four right hand and one left hand stump insufficiency after pneumonectomy are presented in this study and we have classified the up to now published therapeutical results.

Adenocarcinoma↗
PubMed1990

Imaging of cerebral arterio-venous malformations by transcranial colour-coded real-time sonography.

Transcranial color-coded real-time sonography (TCCS) is a new diagnostic method allowing the non-invasive imaging of parenchymal and vascular structures of the adult brain through the intact skull. A description of the sonographic findings in two patients presenting with a radiologically ascertained arterio-venous malformation is provided. The AVM's can be depicted in the two-dimensional B-mode image as echodense areas interspersed with zones of lower echodensity. Their extension correlated with corresponding MRI images. The color-coded illustration of intravascular flow phenomena allowed the distinct identification of the major afferent feeding vessels, the venous drainage and of the vascular convolution of both AVM's. Information on hemodynamics, as e.g. the blood supply of the angioma by the contralateral internal carotid artery, are obtained by color-coded identification of intravascular flow direction including analysis of the Doppler frequency spectrum. All findings obtained by TCCS complied with those established by angiography. We conclude, that TCCS is a suitable method for early diagnosis and long term follow up of cerebral AVM's.

Adult↗
PubMed1990

Suspensions of plant cells in microgravity.

Electrofusion of evacuolated with vacuolated mesophyll protoplasts of Nicotiana spec. was performed as part of the German Sounding Rocket Program (TEXUS). The results indicate a significant increase not only in the yield of 1:1 fusion products, but also in homo- and multifusion products. Heterokaryons obtained under microgravity have been shown to be viable to a higher degree with respect to their ability for light-dependent oxygen evolution (independent of other substrates than bicarbonate). Furthermore we were able to regenerate hybrid plants from suspensions of vacuolated and evacuolated protoplasts which were pulse-treated under microgravity. These expressed characteristics intermediate to those of the parental plants (Nicotiana tabacum (cv. Samsun), evacuolated; N. rustica, vacuolated).

Cell Fusion↗