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Biomedical subjects

W Jung

Publications and source records attributed to W Jung.

At least 199 records · Page 11Linked to original sources
PubMed1993

The role of Ito cells in the biosynthesis of HGF-SF in the liver.

Hepatocyte Growth Factor-Scatter Factor (HGF-SF) is produced by sinusoidal cells in normal rat liver. Analysis of isolated cells has proven that Ito cells (fat-storing cells, hepatic lipocytes) are the source of hepatic HGF. In diseased liver the HGF-expression pattern is more complex. In acute liver injury HGF is expressed by an increased number of resident liver cells, which may be due to recruitment of other nonparenchymal liver cells as well as an increased number of Ito cells due to cell division. In cirrhotic rat liver tissue, the number of HGF-expressing cells is decreased. This may be explained by the complete loss of HGF-expression in myofibroblast-like cells derived from Ito cells. Quiescent Ito cells seem to be in a strategic position to control parenchymal cell proliferation. Activation of Ito cells, which occurs in chronic fibrotic liver disease, may lead to the loss of this control function.

Acute Disease↗
PubMed1992

Effects of chronic amiodarone therapy on defibrillation threshold.

In a prospective and parallel, randomized study, the long-term stability of epicardial defibrillation threshold was evaluated in 22 patients, using a patch-patch lead configuration at the time of implantation and generator replacement. The concomitant antiarrhythmic drug treatment consisted of either mexiletine (720 mg/day) or amiodarone (400 mg/day) and was administered to patients in a randomized and parallel manner. During a mean follow-up of 24 +/- 6 months, the defibrillation threshold increased significantly from 14.3 +/- 2.8 to 17.9 +/- 5.3 J (p < 0.05) for the entire patient group. The increase in the chronic defibrillation threshold was due to a marked increase in defibrillation energy needs in the subgroup of patients receiving amiodarone. Whereas no significant change in the defibrillation threshold was documented in the subgroup of patients receiving mexiletine, the mean defibrillation threshold increased from 14.1 +/- 3.0 to 20.9 +/- 5.4 J (p < 0.001) in those receiving amiodarone. In all patients with increased defibrillation thresholds, reevaluation showed a reduction in the defibrillation threshold after discontinuation of antiarrhythmic drug therapy. The only variable associated with an increase in the chronic defibrillation threshold was amiodarone treatment. These findings suggest that the defibrillation threshold should be measured at each generator replacement and in case of a change in antiarrhythmic drug treatment. In particular, if amiodarone treatment is initiated, it is recommended that the defibrillation threshold should be reevaluated to ensure an adequate margin of safety.

Amiodarone↗
PubMed1992

The pharmacokinetics of two different concentrations of short-acting insulin, intermediate-acting insulin, and an insulin mixture following subcutaneous injection.

To compare the pharmacokinetics of two different concentrations, containing either 40 or 100 IU/ml of short-acting human insulin (Velasulin HM), intermediate-acting human insulin (Insulatard HM), or an insulin mixture (25% short-acting insulin, 75% intermediate-acting insulin; Mixtard HM), three randomized, single-blind, crossover trials were performed using the euglycemic clamp technique. Eighteen healthy volunteers received insulin of either formulation subcutaneously in each of the studies (15 IU Velasulin, 20 IU Insulatard, or Mixtard). The blood glucose levels were maintained constant by glucose infusions. In the trial using Velasulin, the two different insulin concentrations were equivalent regarding the total absorption [area under the curve (AUC) of serum insulin: 126 +/- 28 and 123 +/- 35 mU/l x 12 h for U40 and U100 (mean +/- SD)], but not in regard to the rate of absorption (t max 1.3 +/- 0.4 and 2.4 +/- 1.0 h for U40 and U100). In the case of Insulatard, total absorption was not equivalent (AUC 153 +/- 35 and 128 +/- 37 ml/l x 24 h for U40 and U100), but the rate of absorption was equivalent (t max 4.8 +/- 2.9 and 5.3 +/- 4.6 h). In the Mixtard series, total absorption was equivalent (AUC 142 +/- 32 and 128 +/- 22 mU/l x 24 h), but the rate of absorption was not (t max 2.2 +/- 0.9 and 3.2 +/- 4.2 h for U40 and U100). The glucose requirement was not equivalent in each of the three series.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Hemodynamic effects of amiodarone during acute and chronic treatment in patients with recurrent sustained ventricular tachycardia.

In 15 patients with recurrent ventricular tachycardia, the hemodynamic effects of amiodarone were evaluated under oral loading (1000 mg/day for 14-16 days) and during chronic treatment (600 mg/day for a further 10 weeks). In all patients, coronary artery disease was present with a mean ejection fraction of 37%+/- 10%. The cardiac output during the sinus rhythm, as determined by thermodilution, did not change significantly during loading with amiodarone. During ventricular tachycardia, the cardiac output increased from 3.7 +/- 1.3 to 4.5 +/- 1.6 1/min under the influence of amiodarone in 5 patients. Echocardiographic measurements of the left ventricle dimensions did not show a directed change of the enddiastolic and endsystolic diameters and the fraction shortening at the end of the loading period and after 3 months of maintenance therapy. No negative inotropic effect of amiodarone could be demonstrated in patients with recurrent ventricular tachycardia and impaired left ventricular function due to coronary artery disease.

Aged↗
PubMed1992

Surface mu heavy chain expressed on pre-B lymphomas transduces Ca2+ signals but fails to cause growth arrest of pre-B lymphomas.

Little is known about the role of signals transduced by cell surface IgM (sIgM) expressed during early B cell development. A subclone (1.6) of the late pre-B cell lymphoma 70Z/3.12 was used to study signal transduction by surface mu heavy (H) chain before and after transition to the early immature B cell stage, and the functional consequences thereof. Although kappa L chain expression can be induced on 1.6 cells by LPS or cytokines, immunoprecipitations indicated that the non-induced 1.6 cells expressed mu H chain with an alternative protein(s) which may be a surrogate light chain(s). Consistent with this, anti-mu but not anti-kappa or anti-lambda antibodies caused transient Ca2+ mobilization in noninduced 1.6 cells. The Ca2+ signal was derived from both intracellular stores and Ca2+ influx in either noninduced cells or in cells that had been preinduced to express kappa L chain. Thus, the ability of mu H chain to mobilize Ca2+ as a second messenger does not depend upon the expression of mature L chains. The immature B lymphomas, WEHI-231 and CH1, express mature forms of IgM and undergo growth arrest when stimulated by anti-mu antibody. In contrast, signals generated by mu H chain on either noninduced or preinduced 1.6 cells or in the sIgM+ pre-B cell transfectant 300-19 mu lambda 36/8 did not cause growth arrest. These results suggest that mu H chain expressed on pre-B cells is capable of mobilizing Ca2+, but that this signal alone is insufficient to induce growth arrest in the pre-B cell.

B-Lymphocytes↗
PubMed1992

Soluble CD8, CD25 and CD30 antigens as prognostic markers in patients with untreated Hodgkin's lymphoma.

In a search for serum markers with prognostic value and specificity for disease activity in Hodgkin's lymphoma, we evaluated the clinical significance of soluble suppressor/cytotoxic T-cell antigen (sCD8), soluble interleukin-2 receptor (sCD25) and soluble Hodgkin's associated antigen (sCD30) levels in the serum of 90 patients with untreated Hodgkin's lymphoma (HD). HD patients in advanced stages had significantly higher sCD8 and sCD25 levels than normal controls. The rate of detectable sCD30, which was absent in healthy controls, depended on stage and histological subtype, and was 22% for the entire group. Low sCD25 levels (< 1000 U/ml) predicted an excellent prognosis (100% event-free survival), while patients with high sCD8 levels (> 750 U/ml) or the demonstration of sCD30 had a poor outcome. Therefore, all three markers have prognostic significance. However, only sCD30 correlated strictly with disease activity and seems to be of value for the follow-up of patients in remission.

Adolescent↗
PubMed1992

Electrophysiological and haemodynamic effects of lidocaine and ajmaline in the management of sustained ventricular tachycardia.

The electrophysiological and haemodynamic effects of lidocaine (100 mg) and ajmaline (50 mg) were evaluated while attempting to interrupt sustained ventricular tachycardia. The study was performed as a prospective, non-blinded, randomized investigation in 61 patients. Lidocaine terminated ventricular tachycardia in four of 31 patients, ajmaline in 19 of 30 patients (P less than 0.001). QRS and RR intervals during ventricular tachycardia were prolonged by ajmaline from 164 +/- 28 ms to 214 +/- 49 ms and from 371 +/- 86 ms to 479 +/- 137 ms (P less than 0.001), respectively; lidocaine did not influence these parameters. The duration of the return cycles after termination of ventricular tachycardia did not differ between the two groups. Lidocaine did not change cardiac output during ventricular tachycardia whereas cardiac output increased significantly under ajmaline from 3.5 +/- 1.21.min-1 to 5.5 +/- 1.91.min-1 (P less than 0.001). It is concluded that anti-arrhythmic agents such as ajmaline, which slow conduction velocity and prolong refractoriness, are more effective than lidocaine in the medical treatment of haemodynamically stable, sustained ventricular tachycardia.

Ajmaline↗
PubMed1992

Long-term therapy of antitachycardia pacing for supraventricular tachycardia.

Long-term antitachycardia pacing therapy with the InterTach 262-12 and 262-16 was evaluated in 32 consecutive patients (mean age 50 +/- 13 years) with recurrent, drug refractory supraventricular tachycardia. AV nodal reentrant tachycardia was present in 20 patients, Wolff-Parkinson-White syndrome in ten patients, and a reentrant tachycardia due to Mahaim fibers in one patient. During follow-up of 39 +/- 17 months, 250 persistent tachycardia episodes occurred in 22 patients. By adjusting detection and termination mode, recurrent supraventricular tachycardia could be controlled in 19 of 32 patients (60%) by antitachycardia pacing alone. Concomitant antiarrhythmic drug therapy was required in ten of 32 patients (30%). During follow-up antitachycardia pacing became ineffective in three patients (10%). Thus, chronic antitachycardia pacing proved to be safe and effective in selected patients with drug refractory supraventricular tachycardia and could significantly improve quality of life by rapid termination of recurrent supraventricular tachycardia episodes.

Algorithms↗
PubMed1992

Smoke aldehyde component influences pulmonary edema.

The pulmonary edema of smoke inhalation is caused by the toxins of smoke and not the heat. We investigated the potential of smoke consisting of carbon in combination with either acrolein or formaldehyde (both common components of smoke) to cause pulmonary edema in anesthetized sheep. Seven animals received acrolein smoke, seven animals received a low-dose formaldehyde smoke, and five animals received a high-dose formaldehyde smoke. Pulmonary arterial pressure, pulmonary capillary wedge pressure, and cardiac output were not affected by smoke in any group. Peak airway pressure increased after acrolein (14 +/- 1 to 21 +/- 2 mmHg; P less than 0.05) and after low- and high-dose formaldehyde (14 +/- 1 to 21 +/- 1 and 20 +/- 1 mmHg, respectively; both P less than 0.05). The partial pressure of O2 in arterial blood fell sharply after acrolein [219 +/- 29 to 86 +/- 9 (SE) Torr; P less than 0.05] but not after formaldehyde. Only acrolein resulted in a rise in lung lymph flow (6.5 +/- 2.2 to 17.9 +/- 2.6 ml/h; P less than 0.05). Lung lymph-to-plasma protein ratio was unchanged for all three groups, but clearance of lymph protein was increased after acrolein. After acrolein, the blood-free extravascular lung water-to-lung dry weight ratio was elevated (P less than 0.05) compared with both low- and high-dose formaldehyde groups (4.8 +/- 0.4 to 3.3 +/- 0.2 and 3.6 +/- 0.2, respectively). Lymph clearance (ng/h) of thromboxane B2, leukotriene B4, and the sulfidopeptide leukotrienes was elevated after acrolein but not formaldehyde.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrolein↗
PubMed1992

Failure of an implantable cardioverter-defibrillator to redetect ventricular fibrillation in patients with a nonthoracotomy lead system.

BACKGROUND: Shock delivery of an implantable defibrillator may cause a change in the amplitude of endocardial electrograms and impair the detection of ventricular fibrillation. Thus, the effects of shock discharges on the amplitude of endocardial electrograms were evaluated in five patients undergoing implantation of a cardioverter-defibrillator in combination with a new nonthoracotomy lead system. METHODS AND RESULTS: At implant, bipolar endocardial electrograms were recorded before each shock application, during ventricular fibrillation, during redetection of ventricular fibrillation in case the applied shock was ineffective, and at intervals of 5, 10, 20, 30, 60, and 120 seconds after each shock delivery. The amplitude of the endocardial electrograms decreased from 10.5 +/- 3.8 mV during sinus rhythm to 6.3 +/- 1.9 mV during initial ventricular fibrillation and declined to 2.2 +/- 1.3 mV during redetection of ventricular fibrillation. After successful termination, the following bipolar electrograms could be obtained at the predetermined intervals: 1.9 +/- 1.2 mV, 3.1 +/- 1.8 mV, 4.5 +/- 1.9 mV, 6.5 +/- 2.9 mV, 9.5 +/- 3.3 mV, and 10.4 +/- 3.8 mV. At predischarge testing, failure of redetection of ventricular fibrillation could be documented in two patients, requiring rescue external defibrillation in both cases to restore sinus rhythm. CONCLUSIONS: These findings demonstrate that the implantable cardioverter-defibrillator did not ensure reliable redetection of ventricular fibrillation in patients using the implanted nonthoracotomy lead system. Thus, the potential risk of sudden cardiac death may persist in these patients despite defibrillator therapy.

Cardiomyopathy, Dilated↗
PubMed1992

Phenytoin and carbamazepine decreased oral bioavailability of praziquantel.

Antiepileptic drugs, especially carbamazepine and phenytoin, are potent liver enzyme inducers. Since praziquantel, the drug used to treat neurocysticercosis, undergoes extensive liver first-pass metabolism, we carried out a prospective study to verify whether there was a decrease in oral bioavailability induced by carbamazepine and phenytoin. Carbamazepine and phenytoin significantly decreased concentrations of praziquantel, due to increased clearance secondary to induction of first pass-liver metabolism. The magnitude of the decrease is surprisingly high and may be responsible for failures of treatment.

Adult↗
PubMed1992

The clinical significance of cytokines and soluble forms of membrane-derived activation antigens in the serum of patients with Hodgkin's disease.

In a search for specific serum markers with prognostic impact in Hodgkin's Disease (HD), we evaluated the clinical significance of several cytokines (IL-1 beta, IL-2, IL-3, IL-6, G-CSF, GM-CSF, TNF-alpha) and soluble forms of membrane-derived antigens (sCD4, sCD8, sCD23, sCD25, sCD30) in the serum of patients with untreated HD. Elevations of three groups of serum factors were observed: Firstly, elevations of the hematopoietic cytokines GM-CSF (detected in 39%), IL-6 (57%) and IL-3 (13%), which occurred simultaneously in the majority of the cases; secondly, simultaneous elevations of the inflammatory cytokines TNF-alpha and IL-1 beta (detected in 7%); and finally, elevations of membrane-derived activation antigens sCD8, sCD25, and sCD30. While the cytokine levels did not correlate with other obvious parameters, the membrane-derived activation antigens sCD8, sCD25 and sCD30 were associated with a poor prognosis. Only sCD30 correlated with disease activity and holds promise for the follow-up of patients in remission. Further investigations of these parameters at the cellular level might help to elucidate the enigmatic biology of HD.

Antigens, CD↗
PubMed1992

[Combination anti-arrhythmic drug therapy].

Antiarrhythmic treatment with single agents is often ineffective and can be limited by dose-dependent side-effects. Therefore, combinations of antiarrhythmic drugs in smaller and well-tolerated doses are advocated in cases refractory to single antiarrhythmic drugs. Basically, substances belonging to the same electrophysiologic class should not be combined. A combination of beta-adrenoreceptor blockers with class I antiarrhythmic drugs may be effective, mainly in cases in which the arrhythmia is dependent on adrenergic stimulation. As shown in our study, the combination of class III and I B-substances can be useful in some cases, from the electrophysiological and clinical points of view. Among the successful combinations of this type are amiodarone and mexiletine, sotalol and mexiletine, and sotalol and tocainide. In patients refractory to amiodarone alone or to a combination with mexiletine, the combined treatment with amiodarone and class-I-C drugs such as flecainide and encainide prolongs the cycle length of ventricular tachycardia, but does not suppress induction of ventricular tachycardia during programmed stimulation. Combination therapy with amiodarone and encainide is associated with a remarkable incidence of proarrhythmic effects. Nevertheless, a combination of antiarrhythmic drugs improves efficacy of therapy in selected patients. However, a close monitoring is mandatory because of the risk of proarrhythmia.

Amiodarone↗
PubMed1992

[Wolff-Parkinson-White syndrome: regional endocardial potential and efficacy of high frequency ablation].

The aim of the study was the evaluation of results of radiofrequency (RF) catheter ablation in relation to characteristics of regional endocardial potential morphology. 418 RF current deliveries in 26 patients with anterogradely conducting left-sided accessory pathways (AP) were investigated. A large regional atrial deflection (> 1/4 of ventricular potential) prior to RF discharge is a prerequisite for ablation success using the ventricular approach. A failing or extremely short (< 10 ms) isoelectric interval between atrial and ventricular deflections of the regional potential predicts a block of the AP. A persistent block can be expected if the regional electrogram contains an AP potential and the AP block occurs early (< 5 s) during onset of RF current.

Adult↗
PubMed1992

[Who should be referred for electrophysiologic studies?].

Prerequisite of a rational antiarrhythmic therapy is the correct diagnosis of the given cardiac rhythm disorder. The majority of intermittent and latent cardiac arrhythmias can be reliably induced and analyzed during the electrophysiologic study (EPS). In case of bradyarrhythmias, the method is indicated in patients with suspected sinus node disease or high-grade AV conduction disturbances, as far as the cause of clinical symptoms cannot be settled by Holter recordings. Since patients with paroxysmal supraventricular tachycardias (WPW syndrome and AV nodal reentrant tachycardia) can be cured by transvenous ablation techniques, EPS is indicating in this setting in all symptomatic patients for the diagnosis and the treatment of the given arrhythmia. In patients with recurrent ventricular tachyarrhythmias, EPS should be performed to establish the diagnosis and to control medical treatment; in addition, EPS is a prerequisite for nonpharmacologic treatment modalities such as defibrillator therapy and transvenous or surgical ablation techniques. In survivors of cardiac arrest without new Q-wave myocardial infarction, persistent ventricular tachyarrhythmias can be induced in some 50% of the patients. Patients should be evaluated by EPS in case the reasons for significant clinical symptoms cannot be determined otherwise, given the likelihood, that brady- or tachyarrhythmias are the cause of the clinical symptoms; this includes patients with organic heart disease and with unexplained syncopes.

Arrhythmias, Cardiac↗
PubMed1992

[Clinical assessment and indications for automatic defibrillation].

A variety of therapeutic options including pharmacological treatment, surgical procedures, ablation interventions and electrotherapy are available for the management of patients who are subject to symptomatic ventricular tachyarrhythmias. Patients with documented sustained ventricular tachycardia or ventricular fibrillation are usually controlled by serial electrophysiological studies. About 30 to 60% of these patients respond to antiarrhythmic drugs during serial electrophysiological testing. Patients with severe left-ventricular function respond less frequently than those of well-preserved function. Long-term follow-up studies have demonstrated that, if ventricular tachyarrhythmias can no longer be induced on antiarrhythmic drugs or if inducibility is at least rendered more difficult, the rate of recurrences is low. In contrast, patients with still inducible ventricular tachyarrhythmias may have a poor prognosis and may suffer from frequent recurrences or may even die suddenly. Thus, nonpharmacological strategies such as an implantable cardioverter/defibrillator, transvenous catheter ablation and map-guided antitachycardia surgery have become important alternatives for drug refractory patients. Since the introduction of the implantable cardioverter/defibrillator using a nonthoracotomy approach, the intraoperative and perioperative mortality and morbidity has been significantly reduced. A widespread use of these newer devices required the establishment of guidelines for the appropriate application of this new treatment modality. Surgical, medical and economic considerations make it imperative that defibrillator therapy should be chosen on a basis of careful patient selection. The presenting clinical arrhythmia and its hemodynamic stability, underlying heart disease and left-ventricular ejection fraction should be taken into consideration.(ABSTRACT TRUNCATED AT 250 WORDS)

Electric Countershock↗