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Biomedical subjects

E Hoffmann

Publications and source records attributed to E Hoffmann.

At least 145 records · Page 8Linked to original sources
PubMed1993

[Primary malignant lymphoma in the appendix vermiformis].

Primary gastrointestinal lymphoma (PGL) is a rare condition. A case story concerning a 17 year old boy is presented and discussed. The symptoms were fever and pain in the lower right quadrant of the abdomen, where a tender tumor was palpable. The tentative diagnosis was periappendicular abscess and the patient was treated with antibiotics. As the tumor persisted, a laparotomy with resection of the coecum was performed. Histologic diagnosis was malignant lymphoma originating in the appendix. There was no sign of dissemination in the abdomen. Postoperative treatment with chemotherapy and radiation was carried out. PGL in the appendix in young patients, almost entirely males, will as here often be of the Burkitt type. The histologic type of the tumor, the staging and the radicality at operation are important with regard to prognosis.

Adolescent↗
PubMed1993

Plasma levels of atrial natriuretic peptide and hemodynamic function in cardiac disease.

Plasma concentrations of atrial natriuretic peptide were measured in eight patients with cardiac disease but normal resting right atrial pressure, during cardiac catheterization. No patient had clinical evidence of overt heart failure. An increase in peptide concentrations was observed between the aorta or the peripheral vein and the pulmonary artery. A linear relation was found between peripheral vein and pulmonary artery peptide concentration. Mean pulmonary artery and capillary wedge pressure also correlated with the peptide levels. No correlation was observed between mean right atrial pressure and peptide concentration. These findings demonstrate that atrial natriuretic peptide release, even in the absence of cardiac failure, seems at least partly regulated by left atrial pressure. Finally, peripheral levels reflect the central concentrations of atrial natriuretic peptide.

Adult↗
PubMed1993

Intestinal microsporidiosis in a Chilean patient with acquired immunodeficiency syndrome (AIDS).

A 24-year-old male patient with AIDS diagnosed in 1989, and with several episodes of pneumocystosis, was admitted because of a chronic diarrheic syndrome and severe epigastric pain. Endoscopy showed a granular duodenal mucosa. Light microscopy showed a moderate villous atrophy with round-cell inflammatory infiltration of the chorion. Giemsa, Ziehl-Neelsen, and Gram stains showed microsporidial spores measuring between 1.5 and 2 microns in the supranuclear cytoplasm of some enterocytes. Electron microscopy showed sporoblasts and spores consistent with Enterocytozoon bieneusi, with an apparently non-tubular, rather electron-dense polar filament showing up to 7 coils and also a microtubular internal structure with annular disposition, a finding which has not been adequately emphasized in the pertinent literature, probably representing a contractile property of the polar filament, rather than a mere duct for the parasitic sporoplasm to be inoculated.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Temperature-controlled radiofrequency catheter ablation of AV conduction: first clinical experience.

A new technique for catheter ablation of atrioventricular (AV) conduction, using temperature-controlled radiofrequency energy and a bipolar asymmetrical electrode configuration, was applied to 12 patients (mean age, 48 +/- 15 years; range, 18-69 years) with medically refractory atrioventricular nodal reentrant tachycardia (AVNRT) or rapid atrial rhythms. The energy source was a 500 kHz generator with automatic power regulation to a preselected temperature of 80 degrees C. A specially designed 7 F bipolar asymmetric thermo-catheter was used for ablation in all cases. The endpoints of the procedure were: first-degree AV block in patients with AVNRT and third-degree block in patients with atrial fibrillation or flutter. Energy was applied over a range of 1-14 times per patient. After a mean follow-up of 8 +/- 4 months, third- or first-degree AV block persisted in eight patients. In comparison to constant-power radiofrequency ablation, where impedance rises are commonly observed, no impedance rise or coating of the electrode occurred during any of the 97 energy applications in this study. Variable wall contact of the electrode was identified in 20 of 97 applications by a slow temperature rise or a drop in temperature and frequent power adjustments. Thus, monitoring temperature and automatic power regulation may help to reduce the total delivered energy. Temperature control during radiofrequency energy avoids coagulum formation and consequently the associated potential hazards of constant-power application.

Adolescent↗
PubMed1993

Randomized crossover comparison of the electrophysiologic and antiarrhythmic efficacy of oral cibenzoline and sotalol for sustained ventricular tachycardia.

We compared the electrophysiologic and clinical effects of oral cibenzoline and sotalol in 12 patients with spontaneous and inducible sustained ventricular tachycardia (VT), using a randomized, open-label, cross-over study. Electrophysiologic studies were performed in the control state, after oral cibenzoline and after oral sotalol, using an incremental dose-titration protocol. Therapy with cibenzoline at the maximum dose level (130-390 mg/day) resulted in complete suppression of VT in 1 of 12 patients (8%). Sotalol (160-320 mg/day) prevented induction of VT in 4 of 12 patients (33%). The effective refractory period (ERP) of the right ventricle was more significantly prolonged with sotalol (p < 0.001) as compared with cibenzoline (p < 0.05). Neither drug prolonged QT duration corrected for frequency (QTc) and cycle length of induced VT, as compared with the control study. Three patients experienced spontaneous VT after cibenzoline administration, and 2 patients experienced incessant VT during programmed electrical stimulation. No patient had a proarrhythmic effect while receiving oral sotalol treatment. Chronic sotalol therapy maintained long-term arrhythmia suppression in all 4 responders at 1-year follow-up. Sotalol appears to have greater efficacy than and a safety profile superior to that of cibenzoline. Drug-related proarrhythmic effects of oral cibenzoline therapy occurred with greater frequency than that associated with other antiarrhythmic drugs. Based on these findings, cibenzoline cannot be recommended for use in patients with VT.

Administration, Oral↗
PubMed1993

Cyclopeptide analogs for characterization of the neuropeptide Y Y2-receptor.

A discontinuous 17-amino acid peptide analog of neuropeptide Y (NPY), NPY 1-4-Ahx-25-36 containing 6-aminohexanoic acid instead of the residues 5 to 24, was found to bind preferentially to Y2 subtypes of NPY receptors. In order to further characterize the binding site, three different types of cyclic analogs were synthesized. Firstly lactamisation between residues 2 and 30 led to the most selective Y2-agonist, secondly lactamisation between the N-terminus and residue 31 reduced binding significantly. Thirdly, any cyclization including the C-terminus led to an inactive compound. Circular dichroism revealed different conformations for the three analogs with reduced alpha-helical content in comparison to the linear ana-log. The different conformation of the peptides has been confirmed by molecular dynamics simulations. A model for peptide-receptor interaction is suggested.

Amino Acid Sequence↗
PubMed1993

[A new method for calculating the mass of the left ventricle by angiocardiography].

The authors describe a simplified method to determine left ventricular volume and mass from the ventricular silhouette, taken from a right oblique anterior angiographic projection at 30 degrees, used to measure the telediastolic surface and major axis, and of measuring the telediastolic thickness of the ventricular wall in the postero-lateral segment of the silhouette taken from a left oblique anterior angiographic projection at 60 degrees. Sixty-four ventricular silhouettes were analysed in patients undergoing left kineventriculography for coronaropathy and ventricular mass was determined using both the new and traditional methods. Using the new method mass values (mean value 87.85 g/sq.mt. and SD 34.04) were obtained which were significantly correlated (r = 0.999) with values obtained using the standard method (mean value 88.02 g/sq mt and SD 34.11). The practical advantages of the new method are discussed (simplicity of calculating equation without determining the minor axis of the ventricular silhouette), together with its limits due to the monoplanar technique used to calculate the volume and the measurement of wall thickness in those cases in which the postero-lateral wall is considered the most representative of the mean thicknesses of the left ventricular wall. Lastly, the paper discusses the possibility of applying this method to non-invasive procedures, such as the two dimensional echocardiogram, where more reliable mass values could be obtained even in the event of non-uniform wall thickness.

Angiocardiography↗
PubMed1993

[Electrotherapy of supraventricular tachycardia (atrial fibrillation/atrial flutter)].

Contrary to patients with the WPW-syndrome and AV nodal reentry in whom radiofrequency catheter ablation is the therapy of first choice for cure from these arrhythmias instead of life-long medical therapy, pharmacologic therapy of atrial fibrillation and atrial flutter remains the treatment of choice in these patients. If, however, atrial fibrillation with rapid atrioventricular conduction is medically intractable and associated with severe haemodynamic impairment, these patients may be offered catheter ablation of AV conduction by radiofrequency energy. Compared to DC ablation, this approach is associated by an acceptable complication rate. Including the left ventricular approach in cases where it is not possible to ablate AV conduction using the venous approach, the success rate to achieve third degree AV block approaches 100%. With the development of temperature-controlled radiofrequency catheter ablation, a further reduction of side effects is anticipated. A disadvantage of this approach is the need for permanent pacemaker implantation (usually rate-adaptive VVI stimulation) after induction of complete AV block. Therefore, the advantage of normalization of ventricular rate by ablation of AV conduction has to be weighed against the risk of life-long pacemaker treatment for complete AV block in every patient. Patients with medically intractable typical atrial flutter may be offered the following alternative modes of electric treatment: selective ablation of the area of slow conduction sustaining circus movement in the right atrium underlying atrial flutter, by radiofrequency energy without interrupting AV conduction, implantation of a permanent antitachycardia pacemaker with electrodes positioned in the right atrium, radiofrequency catheter ablation of AV conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1992

A comparison of electrophysiologically guided antiarrhythmic drug therapy with beta-blocker therapy in patients with symptomatic, sustained ventricular tachyarrhythmias.

BACKGROUND: Antiarrhythmic drug therapy guided by invasive electrophysiologic testing is now widely used in patients with symptomatic, sustained ventricular tachyarrhythmias. METHODS: We conducted a prospective, randomized trial in 170 patients to investigate whether this approach would improve long-term outcome. Patients whose arrhythmia was inducible by programmed electrical stimulation were assigned to treatment with electrophysiologically guided drug therapy based on serial testing (61 patients) or with metoprolol (54 patients). Electrophysiologically guided therapy consisted of serial testing of antiarrhythmic agents to identify the first one that rendered the arrhythmia noninducible. The 55 patients whose arrhythmia was noninducible during the initial electrophysiologic test were also treated with metoprolol. RESULTS: During a mean (+/- SD) follow-up period of 23 +/- 17 months, recurrent, nonfatal arrhythmia occurred in 44 patients and sudden death due to cardiac factors in 27. The incidence of symptomatic arrhythmia and sudden death combined was virtually the same in the two groups with inducible arrhythmia after two years of observation (electrophysiologically guided therapy vs. metoprolol therapy, 46 percent vs. 48 percent). The outcome was more favorable in the patients with noninducible arrhythmia at base line (75 percent had neither adverse event) than in those with inducible arrhythmia who were assigned to metoprolol therapy (P = 0.009 by log-rank test). Only 6 of the 29 patients (21 percent) with inducible arrhythmia that became noninducible during drug therapy had recurrent arrhythmia or sudden death, as compared with 21 of the 32 patients (66 percent) with arrhythmia that continued to be inducible (P less than 0.001). A multivariate regression analysis identified continued inducibility of the arrhythmia as an independent predictor of recurrent arrhythmia or sudden death (relative risk, 7.3; 95 percent confidence interval, 2.3 to 23.2; P less than 0.001). CONCLUSIONS: As compared with metoprolol therapy, electrophysiologically guided antiarrhythmic drug therapy did not improve the overall outcome of patients with sustained ventricular tachyarrhythmias. However, effective suppression of inducible arrhythmia by antiarrhythmic drugs was associated with a better outcome than was lack of suppression.

Adrenergic beta-Antagonists↗
PubMed1992

A novel cyclic analog of neuropeptide Y specific for the Y2 receptor.

The low-molecular-mass, cyclic analog of neuropeptide Y, [Ahx5-24, gamma-Glu2-epsilon-Lys30] NPY (YESK-Ahx-RHYINKITRQRY; Ahx, 6-aminohexanoic acid; NPY, neuropeptide Y), was synthesized and investigated for receptor binding, inhibition of forskolin-stimulated cAMP accumulation, inhibition of electrically stimulated rat vas deferens contractions and ability to increase blood pressure. Like the linear peptide [Ahx5-24] NPY (YPSK-Ahx-RHYINLITRQRY), the more rigid, cyclic analog showed good correlation between receptor binding to rabbit kidney membranes and biological activity in the vas deferens assay. Binding of this peptide to a new Y2-receptor-expressing cell line was slightly reduced, compared to the linear peptide [Ahx5-24] NPY, however inhibition of cAMP accumulation was even more efficient. Unlike the linear peptide [Ahx5-24] NPY, the cyclic analog did not induce a blood pressure increase in rats. Reduced binding to Y1 receptor-expressing SK-N-MC cells, as well as the loss of capability of signal transduction, suggest that only Y2-mediated activity is preserved after cyclization. The selectivity of the cyclic compound for Y2 subtypes of NPY receptors with respect to inhibition of cAMP accumulation is more than fortyfold increased, as compared to the linear NPY-(13-36) peptide, which has been used to determine Y2 selectivity so far.

Amino Acid Sequence↗
PubMed1992

[Massive gastrointestinal hemorrhage from a hepaticojejunostomy in pancreatogenic mesenteric vein thrombosis. Diagnosis and therapy].

Gastrointestinal hemorrhage in a patient with a biliodigestive anastomosis necessitates exclusion of a bleeding source in the region of the choledocho- or hepaticojejunal anastomosis. This cannot be achieved by endoscopic methods. The source of bleeding can sometimes, though rarely, be localised by performance of selective angiography during hemorrhage. Laparotomy with exploration of the anastomosis during such an episode is at the same time a diagnostic and a therapeutic intervention. The surgical procedure of choice is de-anastomosis, resection of the bypassed jejunal loop and formation of a hepatico-duodenostomy.

Anastomosis, Roux-en-Y↗
PubMed1992

Biophysical parameters of radiofrequency catheter ablation.

Radiofrequency catheter ablation has been shown to be an effective treatment for patients with accessory pathways in Wolff-Parkinson-White syndrome and other supraventricular tachycardias. However, the biophysical parameters used so far in vivo did not correlate to the size of myocardial lesions and provided no information about the myocardial wall contact of the electrode. In this study 104 radiofrequency applications were performed on excised pig myocardium in circulating heparinized pig blood as well as in blood alone, and root mean square (rms) voltage, root mean square current and phase angle were measured using a specially developed device. The calculated effective power and output power differed by only 2-7% when measured at the point of maximum current during coagulation. A drop of current following a rise in impedance led to a phase displacement of more than 80 degrees and thereby to a drop of effective power to 17% of the output power. Hence, apparent output power consists mainly of ineffective power. The time dependent variations of phase angle, impedance and current were found to be useful for distinguishing between the media blood and myocardium. These results show that physical parameters measured during radiofrequency catheter ablation may help to control electrode position in the clinical situation and reduce the number and duration of ineffective energy applications.

Animals↗
PubMed1992

[The magnesium and calcium content of pre- and postmenopausal myometrium].

Magnesium and calcium, as well as sodium and potassium, have an important influence on the physiology of contraction of the uterus. The ionic concentrations in the pre- and postmenopausal myometrium were examined. We assumed, that there are differences in the electrolytic contents because of the different functions of the corpus, isthmic part and cervix uteri during pregnancy and throughout labour. Small tissue samples from 37 premenopausal and 20 postmenopausal patients, who underwent an operation with different indications, were dissected after hysterectomy. Magnesium and calcium levels were determined by atomic absorption spectrophotometry and potassium and sodium by emission spectrometry in the wet tissue. In both groups, we found significant differences of the electrolytic contents of the myometrium. In the premenopausal uteri, the magnesium levels decrease significantly (p < 0.001) from the corpus (mean = 4.14 mmol/kg) to the cervix (mean = 2.14 mmol/kg). The same scenario can be observed for the potassium levels (Corpus mean = 56.2 mmol/kg and cervix mean = 25.4 mmol/kg). In contrary, the calcium levels (Corpus mean = 1.60 mmol/kg and cervix mean = 2.26 mmol/kg) and sodium levels (Corpus mean = 69.3 mmol/kg and cervix mean = 93.0 mmol/kg) increase significantly (p < 0.001). In the postmenopausal group, we found slightly elevated concentrations of magnesium, sodium and potassium. Only the calcium content of the corpus uteri rises up to three times about 20 years after the menopause (from mean = 1.60 mmol/kg) (p < 0.001). The electrolytic contents in the myometrium were shown to be different in the corpus, isthmus and cervix uteri.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Diagnosis of mycobacterial infections by PCR and restriction enzyme digestion.

A method for the diagnosis of mycobacterial infections by PCR amplification followed by selective restriction enzyme digestion of the PCR product was developed. The amplified DNA sequence used in this study occurs within the gene encoding for the mycobacterial 65 kDa heat shock protein (Hance et al. 1989), which is found in all mycobacteria. However, there are minute differences in the amplified sequence from the Mycobacterium tuberculosis complex compared with the corresponding sequence from the Mycobacterium avium complex. These differences made it possible to rapidly identify to which mycobacterial complex a particular sample belonged by restriction enzyme digestion of the PCR product. A total of 66 samples were tested and all of them were correctly identified. This and similar methods should provide a sensitive, specific and rapid (within 12 h) way of diagnosing mycobacterial infections to the species level.

Animals↗