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Biomedical subjects

H Klein

Publications and source records attributed to H Klein.

At least 199 records · Page 11Linked to original sources
PubMed1990

Perceived consequences associated with the use of beer, wine, distilled spirits, and wine coolers.

Based on a national probability sample of 2,401 Americans aged 21 and over (1,069 of whom were deemed "drinkers" on the basis of having drunk at least one alcoholic beverage in the past 7 days), this study examines which of six specific problems people associate with the use of beer, distilled spirits, wine, and wine coolers. It was found that people are most likely to associate alcoholism, birth defects, drunk driving, and fighting and rowdy behavior equally with these four types of alcohol. But when beverage associations are made, distilled spirits and beer are blamed most frequently for these problems, whereas wine and wine coolers are virtually never thought of as being closely related to any of the problems under study. It was also determined that nearly 1 out of every 7 drinkers surveyed stated that birth defects are unrelated to alcohol use of any kind.

Accidents, Traffic↗
PubMed1990

Effect of interleukin 3 on cytosine arabinoside-mediated cytotoxicity of leukemic myeloblasts.

The concept of biologic modification of proliferation and differentiation of myeloid leukemia cells has attracted much attention over the past years. One promising strategy involves the recruitment of leukemic cells into the cell cycle by hematopoietic growth factors in combination with cycle-specific cytotoxic drugs. Because cytosine arabinoside (Ara-C), which targets only cells in S-phase of the mitotic cell cycle, is included in most chemotherapeutic regimens for the treatment of acute myelogenous leukemia, we explored the hypothesis that the recruitment of quiescent immature leukemic blasts into the cell cycle by the early acting growth factor interleukin 3 (IL-3) can increase the efficacy of Ara-C for kill of leukemic stem cells. We show that IL-3 increases the fraction of blasts in S-phase, as assessed by DNA histogram analysis with propidium iodide staining, leading to an enhancement of kill of clonogenic blast cells when combined with Ara-C. Expression of the protooncogenes c-myc, c-fms, and c-fos, known to be linked to cellular proliferation and differentiation, was also altered by IL-3 in Ara-C-treated cultures, further substantiating the role that IL-3 plays as an enhancer of the cytotoxicity of Ara-C.

Antigens, CD↗
PubMed1990

[Prognostic significance of syncope in patients with Wolff-Parkinson-White syndrome].

The prognostic value of syncope in symptomatic patients with Wolff-Parkinson-White syndrome (WPW) is unknown. Therefore, in order to evaluate the sensibility, specificity, positive and negative predictive value of syncope and compare those values with the one obtained for the shortest RR interval (less than or equal to 250 msec) as well as for the anterograde refractory period of the accessory pathway (less than 270 msec), we reviewed the clinical and electrophysiological data of 158 symptomatic patients with WPW. Fourty-eight patients (30%) reported at least one episode of syncope, and 24 out of 158 patients experienced an aborted sudden death, probably due to rapid conduction via the accessory pathway during atrial fibrillation. Syncope has poor sensibility but high specificity in recognizing an aborted sudden death. However, the syncope demonstrated it had a lower prognostic value when compared with other electrophysiological parameters in correctly identifying patients with a history of ventricular tachycardia and/or fibrillation. In conclusion, the data of this study propose the symptom "syncope" as a frequent event in the history of symptomatic patients with WPW referred to electrophysiological study. Generally its presence does not correctly identify patients who experienced an aborted sudden death. Furthermore, its prognostic value is significantly lower than a shorter RR interval (less than or equal to 250 msec) during atrial fibrillation and an anterograde effective refractory period less than 270 msec.

Adult↗
PubMed1990

[Variants of surgical treatment of ventricular tachycardia].

The paper presents the practice of the Hannover++ Surgery Center (FRG) in managing ventricular tachycardias: 122 patients underwent a radical operation by using electrophysiological studies, 92 patients were implanted an automatic cardioverter/defibrillator, 12 had homotopic cardiac transplantation. Coronary heart disease was present in 82%, non-ischemic heart disease was seen in 18%. The outcomes of operations with electrophysiological studies were as follows: deaths were 9% in early periods, relapses occurred in 5% of patients with coronary heart disease and in 46% of non-coronarogenic diseases. The cardioverter/defibrillator was implanted in 71 patients with coronary heart disease and 21 patients with non-coronarogenic diseases. The mean ejection fraction was 32%. The early and late mortality rates were 5 and 19%%, respectively. Out of 19 patients who had undergone transplantation, 17 were alive in follow-ups of 3 to 36 months. The ejection fraction before transplantation averaged 17%. The surgery for ventricular tachycardias with electrophysiological support is a highly effective method of therapy. The implantation of a cardioverter/defibrillator is regarded as a palliative intervention in patients with ventricular malfunction in the absence of an electrophysiological tachycardia substrate or in the presence of polymorphic tachycardia. Cardiac transplantation should be performed chiefly in young patients with evolving major disease. The transplantation may be replaced by implantation of a cardioverter if the former is impracticable or will be performed in future.

Adult↗
PubMed1990

[The implantable automatic cardioverter-defibrillator].

In addition to medical treatment for ventricular tachyarrhythmias which has not proven to be sufficient, nonmedical modes of treatment are available such as electrophysiologically-guided surgical measures and catheter ablation, both of which are restricted to only a relatively small patient population and require further technical refinement. In 1980, Mirowski introduced the automatic implantable defibrillator and, to date, world-wide, this device has been implanted in 8000 patients. CHARACTERISTICS AND IMPLANTATION OF THE AUTOMATIC IMPLANTABLE CARDIOVERTER/DEFIBRILLATOR (AICD): The AICD continuously monitors the electrical activity of the heart, recognizes the onset of threatening ventricular tachycardias and terminates these according to the respectively programmed mode by delivering direct current shocks or stimuli. The currently used defibrillators consist of an impulse generator with lithium batteries and an electrode system. The batteries can charge a capacitor with about 700 volts in five to eight seconds which produces a current with an energy up to 30 Joules on discharge. The current is delivered either by two plate electrodes on the right and left ventricles or a plate electrode on the left ventricle and a spiral electrode inserted in the superior vena cava. The electrodes also serve the purpose of tachycardia detection by means of an electrical signal, the probability density function (PDF), that is, a significant decrease in the potentials to isoelectric. With this, it is only possible to terminate ventricular fibrillation. Additional electrical detection criteria are obtained and analyzed by two adjacently positioned epicardial screw electrodes or a bipolar endocardial electrode, enable identification of ventricular tachycardia as well. If the tachycardia detection criteria are fulfilled, the capacitor is discharged according to its programmed shock energy. In 1988, programmable defibrillators were introduced. Current defibrillator treatment also incorporates the possibility for antitachycardia stimulation. Attempts to use, instead of the monophase, square-wave impulse, a biphasic defibrillation impulse, to achieve a sequential impulse and to make use of the bidirectional impulse extension have rendered improved reliability for tachycardia termination and energy savings. After median sternotomy, the plate electrodes are usually sutured to the epicardium and the spiral electrode for the bipolar ECG is positioned at the anterior aspect of the right ventricle. The generator is implanted on the left side para-umbilically in subcutaneous or subfascial tissue. With the subxyphoid approach to avoid sternotomy, the plate electrode is sutured extrapericardially over the left ventricle and the spiral electrode is positioned at the epicardium. Alternatively, for those in whom prior cardiac surgery has been carried out, a lateral thoracotomy can be used. The defibrillation threshold, that is the lowest possible energy for defibrillation of ventricular fibrillation or ventricular tachycardia, should be determined intraoperatively after stimulation of the arrhythmia. The energy required for termination of a stable ventricular tachycardia is usually less than that for termination of ventricular fibrillation and can be determined postoperatively. A margin of security should be taken into consideration which, for defibrillation thresholds of up to 10 Joules, is about twice the amount of the defibrillation threshold itself.(ABSTRACT TRUNCATED AT 400 WORDS)

Electric Countershock↗
PubMed1990

[Are double potentials an indication of reentry? Intra-atrial catheter mapping in atrial flutter].

A local doubling of atrial potentials was demonstrated in 40 out of 49 electrophysiological investigations with intraatrial catheter-mapping during atrial flutter. Such doubled potentials can be localized in small areas of the right atrium. In these circumscribed areas the distances between the doubled potentials vary. A predilection area inside the right atrium was not detected. The doubled potentials were found in different sites varying from patient to patient: 15 times in the upper, 13 times in the middle, and 12 times in the lower areas of the atrium. In each patient there was a particular reproducible place, where the doubled potentials were found. Sequential activation time mapping seems to show atrial excitation spreading from the area where the doubled potentials were found. We interpreted these findings as evidence of a reentry-circuit. However, the reentry-circuit apparently does not use preexisting anatomical obstacles, but rather a circumscribed pathological alteration in the atrium.

Adult↗
PubMed1990

[Surgical treatment of Wolff-Parkinson-White syndrome--experiences with 87 surgically treated patients].

Since January 1984, 87 patients (pts) (57 male, 30 female; age 3 to 64 years) with Wolff-Parkinson-White syndrome were operated upon. The indication for surgical treatment was documented recurrent, paroxysmal tachycardia refractory to medical treatment in 85 cases. Eleven pts (13%) had additional heart disease. 87 pts had a total of 103 accessory pathways (AP). AP was localized at the left free wall in 68% (70 AP), at the right free wall in 16% (16 AP), and localized septally in 17% (17 AP). Thirteen pts (15%) had multiple AP (10 pts had two and three pts had three AP). 87 AP were known preoperatively, 96 were localized intraoperatively, and seven were diagnosed during reoperation. Twenty-seven pts were left lateral AP were operated by the epicardial approach and 37 pts by the endocardial approach. Patients with right lateral AP were approached by an epicardial technique in six cases, and by a transmural technique in five. Cryotechnique was applied additionally in 85 pts. Twelve pts suffered recurrences, 11 were reoperated. 101 AP (98%) were dissected successfully, of which 13 (13%) were ablated during reoperation. All pts survived the initial operation. Two pts died after reoperation. One pt is pacemaker-dependent due to a persisting postoperative AV block. We conclude that surgical dissection of accessory pathways can now be offered as an alternative to the non-surgical treatment modes, with low risk and yielding a high success rate.

Adolescent↗
PubMed1990

[The occurrence of hereditary congenital arthromyodysplasia (arthromyodysplasia congenita hereditaria) in calves of the Hessian cattle population].

The Arthromyodysplasia congenita hereditaria is marked by the flexion and fixation of the front leg joints. The statistic analysis of all available data from 536 calves showed that male calves and twins are significantly more affected. The course, duration and delivery date in the pregnancy of cows with arthromyodysplastic calves showed no peculiarity. Concomitant defects of arthromyodysplasia of the forelimbs were spine- and heart defects and neuromyodysplasia of the hind legs. Three bulls KUR, KER and ALD were ancestors of 37% of all registered calves. This frequency of arthromyodysplasia in the bloodline of these three bulls seem to be a sign for a genetic factor with a strong penetrance in male calves.

Animals↗
PubMed1990

[A mechanism of terminating atrial flutter using programmed atrial stimulation].

The analysis of 1168 programmed stimulations (PS) from 30 studies during the last 20 years has shown that the termination of atrial flutter (a-flut) by means of PS directly resulted in sinusrhythm (SR) in 45% of cases. SR following a brief atrial fibrillation (a-fib) occurs in 20% of cases, while in 30% of cases a permanent a-fib results. Our study of 107 cases of a-flut have confirmed these results. The technique of stimulation and the atrial rate show no difference in how the result groups are distributed. It seems as if the maximal pacing rates applied play an important role in whether SR or a-fib is brought about. Permanent a-fib was more often the result of a high pacing rate. A comparable relationship is valid for the difference between the a-flut rate and the maximal pacing rate employed. There was no relation to the pacing rate whether SR was achieved directly or after a brief a-fib. The pacing rate and the difference was equally great when the a-flut was terminated into both groups, but significantly less then when permanent a-fib was triggered. There are three possible mechanisms which may be used to explain how an interaction between programmed stimulation and reentry could take place.

Adult↗
PubMed1990

[Therapeutic value of programmed stimulation in atrial flutter].

The results of 181 therapeutic stimulations in cases of atrial flutter (a-flut) have shown that a-flut is terminated in a wide range by means of programmed stimulation (PS). A sinus rhythm (SR) was achieved in 68% of cases; out of these 21% changed to SR after brief atrial fibrillation (a-fib). Permanent a-fib was induced by means of PS in 32% of cases. In patients with previous coronary artery bypass surgery (ACVB) SR is to be reckoned with most frequently. SR occurs here in 89.5% of cases; in idiopathic a-flut in 71.8% of cases. In four further sub-samples SR must be expected in about two-thirds of cases. With congenital lesions after corrective surgery, as well as with aortic valve lesions without valve replacement, SR was achieved in 66.7% of cases, and in 64.7% of patients with coronary heart disease without previous coronary bypass surgery. SR resulted by means of PS in 64.3% of aortic lesions after a valve operation. In 76.7% of cases of mitral valve lesions with postoperative a-flut the result was permanent a-fib. A-fib appeared in 80% of mitral lesions without heart operation. The influence of a heart operation is minimal, with SR after PS only occurring with more significant frequency in patients after coronary bypass surgery. The result of the stimulation is not influenced by the duration of the postoperative phase. The techniques of stimulation, with the exception of high rate pacing, are of equal value. Even a persistent a-flut can be terminated by means of high rate pacing, with an a-fib thereby resulting more frequently. In cases of spontaneous as well as post-operative a-flut therapeutic stimulation is an effective form of therapy.

Adult↗
PubMed1989

Alternative molecular form of human T cell-specific antigen CD27 expressed upon T cell activation.

The CD27 membrane antigen is exclusively present on a large subset of human peripheral blood T lymphocytes and on mature thymocytes. Several observations point towards a specific role of this molecule on activated T cells. Upon T cell activation induced via the T cell receptor complex, CD27 expression greatly increases, while addition of anti-CD27 monoclonal antibodies amplifies the proliferative response. Within the CD4+ subset, only CD27+ T cells provide helper activity for B cell differentiation. Interestingly, CD27 expression differs not only quantitatively, but also qualitatively between resting and activated T cells. On resting cells, CD27 is a disulfide-linked homodimer with subunits of 55 kDa molecular mass. Upon activation, also a 55-kDa monomer seems to occur, while in addition a 32-kDa component is found. The relationship between these two proteins has been investigated. The 55-kDa and 32-kDa molecules do not seem to be physically associated. The two CD27 components are structurally highly homologous as determined by two-dimensional mapping of tryptic peptides. They both express the epitopes recognized by anti-CD27 antibodies, indicating that the 32-kDa molecule is also T cell specific. Both 55-kDa and 32-kDa molecules carry N-linked carbohydrate groups. However, they differ in other, not yet specified, post-translational modifications, and do not arise from a common precursor simply by alternative N-glycosylation. The 32-kDa form may be derived by proteolytic processing from the 55-kDa protein, but most likely not from a larger (common) precursor. Alternatively, both molecules may arise from a common gene by alternative mRNA splicing, or be derived from highly homologous genes. The dramatic change in molecular composition of CD27 suggests a newly acquired function for CD27 on activated T cells.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Probable exclusion of juvenile neuronal ceroid lipofuscinosis in a fetus at risk: an interim report.

In a family with two children affected by juvenile neuronal ceroid lipofuscinosis (JNCL) an attempt was made at the prenatal diagnosis of the disorder. The following tissues from the fetus at risk were investigated by electron microscopy and were found to be free of fingerprint profiles and curvilinear bodies, typical for JNCL: uncultivated amniotic fluid cells, lymphocytes isolated from fetal blood, and fetal skin biopsy specimens. The child was born at the 34th week of gestation and was clinically normal at the age of 15 months. Postnatally, lymphocytes (isolated at the age of 6 and 15 months) and skin tissue (taken at the age of 15 months) were found to be morphologically normal. It is highly unlikely that the child is affected but definite proof of the absence of JNCL remains difficult at this age.

Amniocentesis↗
PubMed1989

Steroid sulfate sulfatase in human benign prostatic hyperplasia: characterization and quantification of the enzyme in epithelium and stroma.

Characteristics and activities of estrone sulfate (E1S) and dehydroepiandrosterone sulfate (DHAS) sulfatases were studied in epithelium and stroma of benign hyperplastic tissues from human prostates. Tissues were obtained by suprapubic prostatectomy, and epithelium and stroma were separated mechanically by standard techniques. The assay procedure comprised homogenization in Tris-buffer, incubation of the homogenate with [3H]E1S or [3H]DHAS, separation of free steroids from nonhydrolyzed steroid sulfates by extraction with ether, and their final quantification by LSC. The main results were: (1) The pH-optimum of the sulfatase was found at pH 7.0. (2) The highest specific sulfatase activity was found in the epithelium and was associated with its nuclear fraction. (3) Michaelis-Menten constants Km (microM) were 8.7 +/- 1.4 (7) and 4.3 +/- 0.8 (5), maximum velocity rates Vmax (nmol/h x mgDNA) were 47.4 +/- 8.8 (7) and 8.4 +/- 1.5 (5) for E1S and DHAS, respectively (means +/- SEM (n]. (4) The enzymatic cleavage of E1-sulfate was competitively inhibited by DHA-sulfate and vice versa with inhibition constants Ki (microM) of 4.0 +/- 0.5 (2) for E1S and 2.7 +/- 0.4 (2) for DHAS. On the basis of these findings, possible roles of steroid sulfate-sulfatases in forming precursors of active androgens and estrogens from the high amounts of E1S and DHAS in blood are discussed.

Aged↗
PubMed1989

Natural history of single vessel disease. Risk of sudden coronary death in relation to coronary anatomy and arrhythmia profile.

214 patients with single vessel disease were followed-up for 1-78 months (mean 48 months). Incidence of sudden death was studied in relation to coronary artery lesions, left ventricular wall motion and ventricular arrhythmias found during ambulatory ECG recording. Incidence of sudden death was 11% (16 of 144) in patients with lesions of the left anterior descending branch (LAD), 8% (4 of 55) in lesions of the right (RCA) and 7% (1 of 15) in those with lesions of the left circumflex (LCX) coronary artery. Coronary artery occlusion was associated with a significantly higher incidence of sudden death (15%, 18 of 123) than high-grade stenosis (3%, 3 of 91) (P less than 0.05). The risk of sudden death increased in patients with complex arrhythmias and occluded LAD or RCA (8 of 38, 21%; 2 of 12, 18%) compared with patients without complex arrhythmias (5 of 34, 15%; 1 of 18, 6%). One patient with LCX occlusion died suddenly. Our data show that the incidence of sudden death in relatively low in patients with single vessel disease. However, there is a high risk of sudden death in patients with LAD or RCA occlusion associated with akinetic left ventricular areas and complex arrhythmias.

Adult↗
PubMed1989

Participation of the cytokines interleukin 6, tumor necrosis factor-alpha, and interleukin 1-beta secreted by acute myelogenous leukemia blasts in autocrine and paracrine leukemia growth control.

Autonomous in vitro growth of myeloid leukemic colony-forming cells may in part result from autocrine production of colony-stimulating factors (CSF). Some acute myeloid leukemia (AML) samples, however, fail to synthesize CSF despite growing autonomously in agar, and are therefore believed to bypass CSF requirements. Cytokines such as IL-6, tumor necrosis factor (TNF)-alpha, and IL-1, products of cells of the myeloid lineage, are known to be involved in growth control of myeloid progenitor cells. Since these molecules may also contribute to autocrine and paracrine growth regulation of myeloid leukemias, we screened a series of AML for cytokine production. In addition, possible roles of IL-6, TNF-alpha, and IL-1 in growth control of AML were investigated in vitro. We show that a substantial proportion of AML cells produce IL-6, TNF-alpha, and IL-1-beta and use these mediators to stimulate their growth by disparate mechanisms: IL-6 acts as a costimulator to enhance CSF-induced clonogenicity of AML blasts. TNF-alpha induces CSF production by endothelial cells and may therefore provide a paracrine loop to support leukemia growth.

Colony-Stimulating Factors↗
PubMed1989

[Syncope in patients with Wolff-Parkinson-White syndrome: clinical data, electrophysiologic substrate and prognostic value].

Syncope in Wolff-Parkinson-White (WPW) patients might be considered a premonitory event heralding the future development of sudden death. Therefore, we reviewed the clinical and electrophysiologic data of 91 WPW patients referred for invasive evaluation of known arrhythmias, in order to assess the incidence and clinical relevance of syncope. Thirty-four patients (37%, Group I) reported the occurrence of 1 or more syncopal episodes, while 57 patients (63%, Group II) had no syncope. These 2 groups did not differ significantly with regard to age, sex, incidence and characteristics of arrhythmias, clinical history and frequency of arrhythmic events, presence of associated cardiac diseases. Eleven patients in Group I and 9 in Group II were resuscitated from a cardiac arrest. The sensitivity (40%), the specificity (64%) as well as the positive predictive value (32%) and the negative predictive value (71%) of syncope vs a cardiac arrest were not significant. There were no statistical differences in the effective refractory period of the right atrium, atrioventricular node, accessory pathway and right ventricle between the 2 groups. Furthermore, no differences were noted in the cycle length of tachycardia (327 +/- 60 ms in Group I and 335 +/- 46 ms in Group II) and in the minimum RR interval during atrial fibrillation (248 +/- 49 ms and 244 +/- 43 ms, in Group I and II, respectively) as well as in the number of patients who had a minimum RR interval during atrial fibrillation less than or equal to 250 ms (15 patients--65%--in Group I and 21 patients--62%--in Group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Effect of recombinant human granulocyte-macrophage colony-stimulating factor in patients with myelodysplastic syndrome with excess blasts.

As part of a broad phase I study of recombinant human granulocyte-macrophage colony-stimulating factor (rh GM-CSF), four patients were treated who had myelodysplastic syndrome (MDS) with excess blasts. The GM-CSF was given daily as an intravenous injection over a period of 30 min for 5 days. A total of 11 cycles were conducted. Each patient received at least two different dose levels. In three patients, three different dosages were delivered. The treatment course was interrupted by a 10-day rest period. Rh GM-CSF was well tolerated, with only minor side effects seen, which included bone discomfort at the lower back, sternum and ribs, and constitutional symptoms such as low grade fever, nausea/vomiting, and mild myalgias. Whereas no increases in platelet and reticulocyte counts were recorded, elevations of absolute neutrophil counts above 100 cells/microliters occurred in all patients. The most striking finding was, however, the development of increases in the number of circulating and bone marrow blast counts that were observed particularly when doses of greater than or equal to 500 micrograms/m2 of body surface area were administered. In line with data demonstrating in vitro induction of proliferation of leukemic blast cells by rh GM-CSF, one may take advantage of blastogenesis induced in vivo that may favor the use of a therapeutic strategy by recruiting quiescent cells into the mitotic cycle which would then represent optimum targets for a subsequent cycle-specific cytotoxic chemotherapy. Such an approach could form the basis for new clinical trials in MDS.

Adult↗