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Biomedical subjects

J Jung

Publications and source records attributed to J Jung.

At least 19 recordsLinked to original sources
PubMed1996

Atrial defibrillation: can modifications in current implantable cardioverter-defibrillators achieve this?

Atrial fibrillation (AF), the most common arrhythmia resulting in hospital admission, is a major health problem. The limited efficacy of antiarrhythmic drugs to control this rhythm disorder and their potential proarrhythmic risk led to the development of new techniques to ameliorate the treatment of AF. Transvenous atrial defibrillation using endocardial electrodes has been shown to be effective at low energy levels. An implantable atrial defibrillator could be a potentially valuable treatment option for patients with paroxysmal AF that is medically refractory. Research is currently under way to investigate several critical issues concerning this new therapeutic concept: long-term efficacy, safety, patient's tolerance, and an acceptable cost/benefit ratio. It is well known that AF often complicates the use of the implantable cardioverter-defibrillator (ICD) for ventricular tachyarrhythmias. Therefore, it would seem desirable to implement the capability for atrial defibrillation into current ICD systems. It has been shown that atrial defibrillation, using endocardial lead configurations specifically designed for ventricular defibrillation, is feasible at energies well within the capabilities of current ICD technology. Further research is needed to evaluate if some enhancement of the lead configuration in combination with possible advanced technology could reduce the atrial defibrillation threshold to a well tolerated level as a prerequisite for automated atrial defibrillation, in ICD recipients with concomitant paroxysmal AF.

Animals↗
PubMed1996

Effects of reperfusion after thrombolysis for myocardial infarction on the signal-averaged electrocardiogram.

Patients with early reperfusion after thrombolysis for acute myocardial infarction revealed a significantly reduced incidence of ventricular late potentials in the signal-averaged electrocardiogram obtained in the chronic post-infarction period in comparison to patients who did not meet the criteria for early successful thrombolysis (14 vs. 39%; P < 0.05). This data demonstrates that early reperfusion might prevent the development of an abnormal electrophysiological milieu after myocardial infarction.

Action Potentials↗
PubMed1996

[The prevalence of sleep-related breathing disorders in patients with implanted cardioverter-defibrillators. The effect on the incidence and circadian distribution of malignant ventricular tachyarrhythmias].

OBJECTIVE: To determine the prevalence of sleep-related breathing disorders (SRBD) on patients who, because of malignant ventricular tachyarrhythmias associated with cardiac disease, have an implanted cardioverter-defibrillator (ICD). It was also investigated whether the frequency and circadian distribution of spontaneous ventricular tachycardia and (or) fibrillation (VTF) can be influenced by SRBD. PATIENTS AND METHODS: 29 consecutive ICD patients (28 men, one woman; mean age 64 +/- 8 years) were investigated by multifunction recordings. 22 patients had coronary heart disease, and seven dilated cardiomyopathy. For each patient the number of VIF episodes per month were recorded, as well as the percentage distribution of the episodes during the day per hour and after grouping into four time periods. RESULTS: SRBDs were recorded in 13 of the 29 patients (45%) (apnoea-hypopnea index [AHI] > 10). The other 16 patients had normal findings (AHI < or = 10). Mean frequency of the registered VTF attacks was similar in both groups (0.41/month with AHI < or = 10 vs 0.44/month with AHI > 10; difference not statistically significant). Averaged percentage distribution pattern showed a maximum frequency in both groups between 6 o'clock and 12 o'clock a.m. There was no significant increase of VTF during the night (10 o'clock p.m.-6 o'clock a.m.) in the group with SRBD (19% with AHI > 10 vs 18.2% with ATF < or = 10; difference not significant). CONCLUSION: There was a high prevalence of SRBD in the patients with ICD and underlying cardiac disease. No influence of SRBD on frequency and circadian distribution of VTF was demonstrated in patients with ICD during long-term observation.

Aged↗
PubMed1996

Characterization of K+ channels in the basolateral membrane of rat tracheal epithelia.

To study K+ channels in the basolateral membrane of chloride-secreting epithelia, rat tracheal epithelial monolayers were cultured on permeable filters and mounted into an Ussing chamber system. The mucosal membrane was permeabilized with nystatin (180 microg/ml) in the symmetrical high K+ (145 mm) Ringer solution. During measurement of the macroscopic K+ conductance properties of the basolateral membrane under a transepithelial voltage clamp, we detected at least two types of K+ currents: one is an inwardly rectifying K+ current and the other is a slowly activating outwardly rectifying K+ current. The inwardly rectifying K+ current is inhibited by Ba2+. The slowly activating K+ current was potentiated by cAMP and inhibited by clofilium, phorbol 12-myristate 13-acetate (PMA) and lowering temperature. This is consistent with the biophysical characteristics of ISK channel. RT-PCR analysis revealed the presence of ISK cDNA in the rat trachea epithelia. Although 0.1 mM Ba2+ only had minimal affect on short-circuit current (Isc) induced by cAMP in intact epithelia, 0.1 mM clofilium strongly inhibited it. These results indicate that ISK might be important for maintaining cAMP-induced chloride secretion in the rat trachea epithelia.

Animals↗
PubMed1996

Sesquiterpene O-naphthoquinones from the root bark of Ulmus davidiana.

Three new sesquiterpene ortho-naphthoquinones, davidianones A, B and C, together with four known compounds, mansonones E, F, H and I, were isolated from the root bark of Ulmus davidiana. On the basis of spectral data including pulse field gradient two-dimensional NMR spectroscopy, the structures of new compounds were established as 3-hydroxymethyl-6,9-dimethylnaphtho(1,8-b,c)pyran-7,8-dione, 6-methoxycarbonyl-3,9-dimethylnaphtho(1,8-b,c)pyran-7,8-dione, 6-dimethoxymethyl-3,9-dimethylnaphtho(1.8-b,c)pyran-7,8-d ion e, respectively. Their antioxidative activities were evaluated by a thiobarbituric acid method using rat liver microsomes, with mansonone F showing the greatest activity.

Animals↗
PubMed1996

Determinants of the natural course of ventricular late potentials after thrombolytic therapy for acute myocardial infarction.

The intraindividual changes of ventricular late potentials and their possible determinants were examined prospectively in 88 consecutive patients (male: 75; mean age: 58 +/- 9 years) after thrombolytic therapy for acute myocardial infarction. Late potential analysis was performed 4 weeks and 12 months after acute myocardial infarction. At the same time, a left heart catheterization was performed to assess the extent of coronary heart disease and left ventricular ejection fraction. The incidence of late potential 4 weeks after acute myocardial infarction was 15% (13/88 patients). Eighteen percent (16/88) of the patients revealed changing results of late potential analysis: 9 patients lost late potential (late potential pos./neg.) 1 year after acute myocardial infarction and 7 patients presented new formation of late potential (late potential neg./pos.). Preserved late potentials were found in four patients (late potential pos./pos.). Late potential analysis remained negative in 68 patients (late potential neg./neg.). There was no influence of age, gender, site of infarction, clinical course, and medical treatment on the natural course of late potential. Changing results of late potential analysis seemed to be correlated with the evolution of left ventricular ejection fraction and the dynamics of coronary heart disease. In the group late potential pos./pos., comparable values for left ventricular ejection fraction were measured at both examinations, whereas late potential neg./neg. had a significant increase in ejection fraction. In the group late potential pos./neg., a significant improvement in left ventricular function was also measured. In contrast, the late potential neg./pos. group tended to have lower left ventricular ejection fractions 1 year after infarction. In the late potential neg./pos. and late potential pos./pos. groups, the extent of coronary artery disease returned to conditions comparable to baseline despite an initial reduction after coronary revascularization performed 4 weeks after infarction. Late potential neg./neg. and late potential pos./neg. revealed a stable benefit gained from coronary revascularization with a persistent reduction in the number of diseased vessels. Dynamic changes in the results of the signal-averaged ECG 1 year after thrombolytic therapy for acute myocardial infarction were observed in 18% of the patients. These changes seem to be correlated with the evolution of left ventricular function and the dynamics of coronary artery disease.

Action Potentials↗
PubMed1996

[Diurnal distribution of spontaneous ventricular tachyarrhythmias in patients with implanted cardioverter defibrillator].

The purpose of this study was to analyze temporal patterns of spontaneous ventricular tachyarrhythmias in patients (p) with implantable cardioverter-defibrillator (ICD). By reading out the ICD-data logs 725 arrhythmic episodes (e) from 43 patients were investigated. After grouping the episodes into four defined time periods (period 1: midnight to 6 a.m., period 2: 6 a.m. to noon, period 3: noon to 6 p.m., period 4: 6 p.m. to midnight) according to the data stored by the device, the percentage of episodes per time period has been calculated for each patient who experienced at least 10 arrhythmic events (n = 22). A significant peak occurrence (mean 34%) could been demonstrated for the morning hours (period 2). Analyzing patients individually, 4 subgroups could be identified: group 1 with an episode peak in period 2 (9 p, 277 e, p < 0.01), group with an episode peak in period 3 (4 p, 83 e, p < 0.01), group 3 with a peak occurrence in period 4 (3 p, 110 e, p < 0.01) and group 4 with an equal episode distribution over all four time periods (6 p, 187 e). Comparing sustained and nonsustained tachyarrhythmias, the nonsustained episodes were found to be distributed much more equally, meanwhile the circadian variation for fast (HR > or = 240/min) and slower (HR < 240/min) arrhythmias was identical. Regarding episodes of patients on beta-blocker or class III-antiarrhythmic therapy the same circadian variation has been found. There was no significant difference between the subgroups of patients with an episode peak in period 2 and the other patients concerning age, sex, cardiac disease, left ventricular ejection fraction, clinical arrhythmia, beta-blocker or class III-antiarrhythmics, number of recorded episodes or follow-up time. Further studies are needed to determine a possible correlation between these findings and different circadian variations in individual psychovegetative activity.

Adult↗
PubMed1995

Safety of antitachycardia pacing in patients with implantable cardioverter defibrillators and severely depressed left ventricular function.

The purpose of this study was to investigate the efficacy and safety of antitachycardia pacing (ATP) in third-generation implantable cardioverter defibrillators (ICDs) for terminating spontaneously occurring ventricular tachycardias (VTs) in patients with severely depressed left ventricular (LV) function. Ninety-one patients with active ATP were followed for 16 +/- 13 months. During this period, 775 VT episodes occurring in 36 patients were treated by ATP. The patients were divided into two groups according to their LV ejection fraction (LVEF): group A with LVEF < or = 30% (n = 20), and group B with LVEF > 30% (n = 16). There were no differences between both groups in age, gender, underlying heart disease, indication for ICD therapy, or drug therapy. The VT rates were comparable (group A: 183 +/- 16 beats/min; group B: 180 +/- 21 beats/min; P = NS). Eighty-three percent of all episodes (n = 332) in group A and 93% of the VTs (n = 443) in group B were ATP terminated (P < 0.01). Ten percent of VTs in group A were accelerated by ATP into the ventricular fibrillation zone versus 2% in group B (P < 0.01). The individual termination rate and acceleration rate per patient were comparable in both groups. All VT episodes unresponsive to ATP were converted by backup shocks. The efficacy of first-shock therapy was similar in both groups (group A: 89%; group B: 97%; P = NS). The proportion of patients who needed at least one backup shock for unsuccessful ATP was comparable in both groups (group A: 65%; group B: 56%; P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Defibrillators, Implantable↗
PubMed1994

High resolution ECG and left ventricular volume after acute myocardial infarction.

The presence of ventricular late potentials (LPs) early after acute myocardial infarction (AMI) was recently reported to correlate with left ventricular dilatation subsequent to AMI. We assessed prospectively the relationship between LP (time domain) in the late phase of AMI and left ventricular end-diastolic volume (EDV) measured by equilibrium radionuclide angiocardiography 4 weeks and 12 months after AMI. In 80 consecutive patients 4 weeks and 12 months after thrombolytic therapy for AMI, LP and EDV were determined (EDV1, EDV2). There was no significant correlation between QRS duration (r = 0.18), RMS40 (r = 0.08), or LAS40 (r = 0.1) and EDV1 or EDV2 in patients with or without LP at baseline. In both groups (patients with [n = 15] and without LP [n = 65]), EDV1 and EDV2 were comparable (128 +/- 32 mL vs 126 +/- 35 mL; 114 +/- 40 mL vs 117 +/- 36 mL; P = NS). In addition, there was no significant difference between EDV1 and EDV2 in patients who developed new LP (n = 6) or lost LP (n = 9) 12 months after AMI. In contrast to LP in the very early phase after AMI, there seems to be no significant correlation between the high resolution ECG in the late phase after thrombolytic therapy for AMI and left ventricular EDV.

Electrocardiography↗
PubMed1994

Treatment of subjects with refractory periodontal disease.

The aim of the present study was to evaluate the effect of non-surgical periodontal therapy with the adjunct of a selected antibiotic in subjects diagnosed with refractory periodontal disease. 21 subjects were selected for the study; all had a history of periodontal surgery, tetracycline therapy, and regular maintenance by a periodontist. When disease activity was detected, a bacterial sample was taken and a whole plaque susceptibility test was performed. Before the outcome of the susceptibility test the subjects were assigned to either antibiotic or placebo therapy. All subjects received scaling and rootplaning prior to antibiotic or placebo therapy. Based on the susceptibility test, subjects in the antibiotic group were treated either with Augmentin or clindamycin. The results demonstrated that in subjects with refractory periodontal disease there was no significant difference (N.S.) in the proportion of sites losing attachment before and after treatment (11.3% and 12.4%, respectively) over a 2-year post therapy observation period. However, the proportion of sites showing gain of attachment increased from 0.9% before therapy to 5.1% (p = 0.029) following selective antibiotic therapy when combined with scaling and rootplaning. The remainder of sites showed no change between pre- and post-therapy monitoring periods. The progression of attachment loss in the active sites could not be completely stopped over the entire 2-year period. After 12-15 months following therapy, there was a tendency towards new loss of attachment and an increase of pocket depth. However, all 4 subjects treated with placebo drug demonstrated continuous deterioration and had to be retreated. Although the proportion of sites losing attachment decreased from 5.1% to 2.3% (N.S.), the proportion of sites gaining attachment also decreased from 2.0% to 1.0% (N.S.). The results suggest that scaling and rootplaning together with selected antibiotic therapy repeated every 12-15 months may be beneficial for these subjects although it may not completely stop progressive attachment loss.

Adult↗
PubMed1994

Cues to start and end drinking episodes as a function of family drinking history.

College students with positive (FH+) and negative (FH-) family history for heavy frequent alcohol use showed no differences in age of first drink, amount consumed then, amount currently consumed, current frequency, maximum consumed, or effect of current alcohol consumed. However, there were FH background differences in the reasons identified for ending, but not for starting, drinking episodes involving intoxication. The realization of already drinking too much ended these drinking episodes more often among FH- than for FH+ subjects. In contrast, nausea and lateness of the hour were related to the end of drinking more often for FH+ subjects.

Adolescent↗
PubMed1994

Epithelial tumours induced by a herpesvirus oncogene in transgenic mice.

To investigate the role of herpesviral genes in tumourigenesis, transgenic mice were generated expressing STP-C, a transformation associated protein of the lymphoma inducing herpesvirus saimiri. Epithelial tumours developed in the salivary gland, pancreas, thymus and liver of transgenic mice within the first weeks of life. Thus, the target cells for tumour formation in the transgenic mice were surprisingly different from those of the herpesvirus from which the oncogene was derived. Our results identify STP-C as a herpesvirus oncogene sufficient for tumour induction without the cooperation of other viral gene products. Furthermore, the results demonstrate pleiotropic transforming capabilities of the STP-C oncogene and suggest that the specificity of lymphoma induction by the virus is determined by factors other than the oncogene itself.

Animals↗
PubMed1993

18q-mosaicism associated with Rett syndrome phenotype.

Rett syndrome consists of a characteristic progressive encephalopathy in females. The cause of this syndrome is unknown. We present a patient with 18q-mosaicism who, along with the characteristics of this autosomal deletion, also fulfills the clinical criteria for Rett syndrome. This may demonstrate heterogeneity within this as yet clinically defined syndrome. A thorough chromosomal analysis should be performed in suspected cases of Rett syndrome.

Adult↗
PubMed1993

Biodegradation of phenol: a comparative study with and without applying magnetic fields.

The objective of this work was to study the effect of magnetic fields on the rate of phenol biodegradation using immobilized activated sludge. A recirculation flow bioreactor employing immobilized bacterial beads was used with phenol as the substrate to study the biodegradation process. This study was conducted by applying separately the north pole and the south pole magnetic fields to the bioreactor. Rate of dissolved oxygen consumption, phenol concentration and extracellular protein concentration were the parameters monitored during the process. It was observed that by applying a magnetic south pole to the process, biodegradation in the form of biological oxidation was enhanced. A 30% increase in biodegradation rate was obtained by applying a magnetic south pole of strength of 0.45 Tesla to the bioreactor with immobilized microbial beads as compared to the control. Magnetic north pole irradiation inhibited this type of biooxidation. This process has potential for biological treatment of organic wastes.

Bacteria↗
PubMed1993

The relationship of worrying, coping, and symptoms among college men and women.

College students maintained a daily log of their worrying for 7 consecutive days, with three different subgroups starting on different days of the week. Patterns of the type and amount of worrying did not vary systematically over successive days. Multiple regression analyses showed a direct relationship between worrying level and amount of psychological symptoms, as measured by both the diary method and a single item self-rating. Avoidance coping was related to higher levels of physical and psychological symptoms, whereas problem solving was associated with fewer psychological symptoms for females. Men and women, for the most part, had similar relationships among the variables.

Adaptation, Psychological↗
PubMed1993

The efficacy of hydrophilic contact lens cleaning systems in removing protein deposits.

New, never-worn, individual hydrophilic contact lenses were incubated in an artificial tear solution (containing lysozyme, albumin, lactoferrin, and glycoprotein) for 24 hours at 37 degrees C with constant stirring. These lenses were then cleaned following the manufacturer's instructions with one of six commercial cleaning systems: AOSEPT, CONSEPT, Oxysept, ReNu, Opti-Free and thermal disinfection in conjunction with the Allergan Enzymatic Contact Lens Cleaner. The protein remaining on each lens after cleaning was removed and then quantified by the Bio-Rad Protein Assay. High resolution gel electrophoresis was used to assess the individual protein profile patterns. We found that only one-third to one-half of the protein deposited on a lens is removed by the above cleaning systems. Of the proteins in the artificial tear solution only lysozyme is removed by cleaning, while lactoferrin, albumin, and glycoprotein tend to remain on the lens. Since many of the complications experienced by contact lens wearers are thought to be related to protein deposits on their lenses, our results suggest the need for more effective contact lens cleaning solutions.

Albumins↗