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Biomedical subjects

R M Klein

Publications and source records attributed to R M Klein.

At least 73 records · Page 4Linked to original sources
PubMed1997

Long-term survival of recipients of allogeneic bone-marrow transplantation after mechanical ventilation.

To evaluate the prognostic significance of mechanical ventilation for outcome of intensive care therapy for pulmonary complications after allogeneic bone marrow transplantation (aBMT) we analysed the clinical course of ten patients requiring intubation and mechanical ventilation after aBMT for pulmonary complications. Ten out of eighty-five patients (12%) undergoing aBMT between 1989 and 1995 required mechanical ventilation for pulmonary complications at our university adult intensive care unit (ICU). Ventilation could be discontinued in four patients after pulmonary function improved. Three of these patients are long-term survivors after two to five years (median 37 months) of follow-up. Significant differences between the two groups of survivors (n = 4 patients) and non-survivors (n = 6 patients) which could have an impact on prognosis exist for graft-versus-host-disease (GvHD), (p < 0.04) and the time between aBMT and intubation (p < 0.05). There were no differences for age (median: 36 and 34 years of age respectively), laboratory values, duration of mechanical ventilation (median: 7 days for both groups) and APACHE-scores. In survivors, mechanical ventilation became necessary because of atelectasis or obstruction by mucositis in two cases, septicemia with concomitant ARDS in one case and bacterial pneumonia in one case. In non-survivors, pulmonary complications were caused by infections. Causes of death were septicemia or septic shock in five cases and GvHD-induced bronchiolitis obliterans in one case. In conclusion patients at risk for fatal outcome after intensive-care therapy for pulmonary complications following aBMT show a higher degree of GvHD, more infectious complications and a later onset of ventilation after aBMT. With an overall longterm-survival of 3 out of 10 patients, mechanical ventilation seems to be live-saving in a selected subset of patients.

Adult↗
PubMed1997

Secretion of cardiac plasminogen activator during hypoxia-induced right ventricular hypertrophy.

In the circulation, fibrinolytic activity is determined to a large degree by the relative levels of tissue plasminogen activator (tPA) and its major inhibitor (PAI-1). Vascular beds in different organs secrete tPA and PAI-1 into the circulation, and the total secretory rate of each protein is balanced by its half-life in the bloodstream. We are testing the hypothesis that in the heart, ventricular hypertrophy will alter the rates of formation of tPA and/or PAI-1 and the rates of their release into the cardiac vasculature. In this study, we have examined the effects of continuous hypoxia on PA activity in extracts of rat heart ventricles, on the activity secreted into the cardiac vasculature of perfused hearts, and on the levels of mRNAs for tPA and PAI-1. Rats were subjected to hypobaric hypoxia at 0.5 atm for 1-21 days. The treatment caused polycythemia within 1-3 days, and right ventricular hypertrophy by 3 days. PA activity in extracts of both right and left ventricles was significantly elevated after 3 days of hypoxia, continued to increase for 4 additional days, and remained elevated for 3 weeks. The actions of inhibitors of urokinase and tPA indicated that the PA activity in heart extracts was exclusively tPA. Fibrin zymography confirmed that result. The mRNAs for tPA and for PAI-1 were elevated after 1 day of hypoxia and then returned to near control levels on days 2 and 3. After 7 days, hearts from hypoxic rats secreted more tPA activity into perfusates than did hearts from controls. The difference in secretory rates was proportional to the differences in the levels of tPA in the corresponding heart extracts.

Animals↗
PubMed1997

[Immunosuppressive therapy for effective suppression of life threatening ventricular tachyarrhythmias in chronic myocarditis].

Chronic myocarditis predisposes to the occurrence of spontaneous ventricular arrhythmias. It is not known if an immunosuppressive treatment-as a casual therapy-leads to arrhythmia suppression. In the present study, 12 patients (four female, eight male, mean age 53 +/- 15 years) with a mean left-ventricular ejection fraction of 52 +/- 19% were included. After exclusion of coronary macroangiopathy, the presence of chronic myocarditis was demonstrated by immunohistological evaluation of right-ventricular biopsies taking the number of specific lymphocytes (CD 2-8), of activated macrophages and the degree of HLA-expression on interstitial and endothelial cells as a basis. Seven patients had a successful resuscitation due to ventricular fibrillation in their case history, three patients presented sustained monomorphic ventricular tachycardia and two syncopes with inducible tachyarrhythmias. As a "conventional" therapy ten patients received antiarrhythmic drugs and four patients an implantable cardioverter/defibrillator. After confirmation of the diagnosis by a second biopsy after 3 months, all patients underwent an immunosuppressive therapy with methylprednisolone. The initial dose of 1 mg/kg body weight was reduced by 20 mg each every 2 weeks, until a maintenance dosage of 8-12 mg/day was achieved. If the control study after 6 months still gave a positive result, a combined therapy with azathioprine, 100-150 mg/day, was carried out for a further 6 months. In nine patients (75%), the control biopsy became negative, in three patients (25%), the biopsy remained to be positive. In the group presenting negative biopsies, no tachyarrhythmia relapse occurred within a follow-up period of 49 +/- 13 months, while in the group with positive biopsies, relapses occurred in two of three patients. Complete suppression during EPS after therapy was achieved in 50% of the patients who were inducible before therapy. In addition to lymphocyte infiltration, particularly HLA expression on endothelial and interstitial cells was significantly reduced; left-ventricular ejection fraction was improved only in tendency, while left-ventricular filling pressure decreased significantly. In summary, in patients with chronic myocarditis and malignant ventricular arrhythmias, a high-dose immunosuppressive long-term therapy results in the significant reduction of inflammatory infiltrations in about 75% of the cases and, at the same time, in the effective suppression of arrhythmias.

Adult↗
PubMed1997

[Early postoperative changes in systolic and diastolic function at rest and during stress in patients with hypertrophic obstructive cardiomyopathy (HOCM) after myectomy].

INTRODUCTION: In this study systolic and diastolic function in patients with hypertrophic obstructive cardiomyopathy (HOCM) and intractable complaints to medication were investigated before and after a mean of 7 months after myectomy. METHODS: Investigations in 19 patients with HOCM included echocardiography, Swan-Ganz-thermodilution-catheter and radionuclide-angiography. RESULTS: Myectomy resulted in a reduction of the intraventricular gradient at rest (40.1 +/- 43.3 versus 7.6 +/- 12.0 mm Hg, p < or = 0.005) and under provocation (92.4 +/- 67.1 versus 21.3 +/- 26.5 mm Hg, p < or = 0.001). Echocardiographically determined basal septal thickness was reduced (24.9 +/- 6.3 versus 20.1 +/- 6.8 mm; p < or = 0.05) and diastolic diameter increased (40.4 +/- 5.2 versus 44.8 +/- 7.1; p < or = 0.05). Exercise tolerance increased from the maximally achieved 64.5 +/- 19.2 to 89.5 +/- 24.0 W (p < or = 0.001). Symptomatic status (NYHA) improved (1.7 +/- 1.4 versus 2.8 +/- 0.3 (p < or = 0.001). Systolic parameters showed at rest an increase in isovolumetric contraction time (65 +/- 39 versus 112 +/- 50 ms, p < or = 0.01), in time to peak ejection (109 +/- 40 versus 188 +/- 42 ms, p < or = 0.001), and a reduced left ventricular ejection fraction (72 +/- 12 versus 64 +/- 11%, p < or = 0.01). Analysis of regional ejection fraction revealed a significant reduction of ejection fraction in the basal septal region (p < or = 0.05). Increase of global and regional ejection fraction under exercise was still preserved. Mean pulmonary capillary wedge pressure was significantly reduced at rest (11.8 +/- 3.8 versus 8.6 +/- 2.4 mm Hg, p < or = 0.05) as well as under exercise (27.0 +/- 7.1 versus 20.4 +/- 6.8 mm Hg, p < or = 0.01), whereas left ventricular enddiastolic volume index (63 +/- 19 versus 72 +/- 17 ml*m-2, p < or = 0.05) was significantly increased. CONCLUSIONS: In patients with HOCM, myectomy reduces intraventricular gradient, increases exercise capacity, and is accompanied by improved diastolic function parameters, while systolic function parameters are generally reduced.

Adult↗
PubMed1997

A spatial gradient of acceleration and temporal extension underlies three illusions of motion.

If an object (or cue), is presented and shortly afterwards a line is drawn with one end near to the object, motion away from the object location is induced within the line. This line-motion illusion has best been explained by postulating a facilitative spatial gradient that accelerates signal transmission most strongly near to the object, and less so with increasing distance away from the object. This simple accelerative-gradient model was tested in four experiments by either briefly presenting the line, or replacing the line rendering with a dot moving at high velocity towards (or away from) the initial object location. Observers first perceived motion away from the cue followed by motion towards the cue (hence this new illusion is referred to as the "two motion percepts", or TMP illusion). The generality of the TMP illusion was investigated through the reports of forty-five inexperienced undergraduates who were presented with TMP displays. Observers who were asked to pictorially reproduce their motion experience, drew a line expanding away from the cue then contracting back towards it 85% of the time. Over 90% of individuals reported experiencing the illusion with a quickly moving dot. The effects of several presentation parameters were investigated by the moving-dot method, and it was concluded that the accelerative-gradient model by itself was inadequate to explain TMP phenomena. Two extended versions of the gradient model are proposed that place the locus of the TMP effects in properties of motion detection mechanisms or in temporal aspects of visual-signal transmission.

Computer Graphics↗
PubMed1997

Metabolic and biomechanical variables of two incline conditions during distance running.

The purpose of this experiment was to examine the effects of an incline during distance running on selected metabolic and biomechanical variables. Six (4 males, 2 females) trained distance runners (age 27.2 +/- 7.8 yr; VO2max 63.7 +/- 7.5 mL x kg-1 x min-1) performed three 35-min runs at speeds corresponding to each individual's anaerobic threshold. The first run (Control) was performed at 0% grade. The remaining two runs were randomly assigned and included a 5% incline during min 5-15 (Run A) or 20-30 (Run B). Heart rate via telemetry (HR), and oxygen consumption (VO2), minute ventilation (VE), RER, and tidal volume (TV) were measured by indirect calorimetry. High speed videography was used to measure time in support phase, time in swing phase, step length, trunk lean, vertical oscillation of the hip, knee flexion in support, shank angle during toe-off, and ankle flexion at heel strike during the runs. Significant increases (P < or = 0.05) were found during the incline conditions of Run A for VO2 (+18%) HR (+11%), VE (+24%), and RER (+8%) and Run B for VO2 (+19%) HR (+10%), and VE (+25%) compared with the Control. No significant differences (P > 0.05) were noted between Run A and Run B during incline running in the physiological variables. No significant differences (P > 0.05) were observed in any of the biomechanical variables among the runs. These data indicate that the energy expenditure required during incline running is the same regardless of incline location during a 35-min run, and running mechanics are not significantly altered during a 5% incline lasting 10 min. In addition, following a 5% incline for 10 min, runners experience no significant physiological or biomechanical changes during subsequent level running at anaerobic threshold pace.

Adult↗
PubMed1997

Evaluation of X-ray beam angulation for successful twin canal identification in mandibular incisors.

This study was undertaken to determine the most effective horizontal beam angulation for the diagnosis of twin canals in mandibular incisors. Two hundred extracted mandibular incisor teeth, in groups of four, were aligned in the form of a lower dental arch and radiographed using a beam alignment device at 10 degrees intervals between 0 degree and 50 degrees from both right and left sides. Five observers with varying degrees of experience were asked to assess the number of canals in each of the four teeth from these radiographs. A further radiograph of each individual tooth was taken at 90 degrees through the mesio-distal plane to identify the number of twin canals present. A random sample of 10% of the radiographs were viewed for a second time 3 months later to assess intra-observer variation. The 20 degrees right and 30 degrees left horizontal beam angulations showed significantly more accurate diagnosis of twin canals than the ortho-radial view (0 degree) by all five observers. Analysis of the inter-observer results suggests that the experienced viewers were no better but more consistent at identifying twin canals in mandibular incisors.

Dental Pulp Cavity↗
PubMed1997

[Indications and limits of conventional revascularization methods in coronary heart disease].

The number of cardiologic patients undergoing invasive diagnostic catheterization is rapidly increasing. Due to more liberal and extensive indications for invasive diagnosis patients in relatively unfavorable clinical condition (e.g., elderly patients with severe extracardial disease, patients status post CABG) are being catheterized and, if suitable and indicated, undergo revascularization procedures. With rapidly increasing procedural skill of cardiovascular surgeons and invasive cardiologists even high-risk patients with severe coronary artery disease or underlying illness, who were classically excluded from surgical or catheter-invasive revascularization, are now being treated more aggressively. The changing indications for diagnostic catheterization and significant changes in the different modes of revascularization--operative bypass-surgery or interventional procedures--have led to continuous changes in the differential indications for these invasive therapeutic strategies. This article reviews and discusses the currently accepted indications for surgical and interventional revascularization as well as the limitations of these procedures.

Adult↗
PubMed1996

[Systemic Nocardia asteroides infection with endocardial involvement in a patient undergoing immunosuppressive therapy].

HISTORY: A 62 year-old male patient developed malaise, unproductive cough and high temperature (39.5 degrees C) during immunosuppressive therapy with methylprednisolon and cyclosporin A six months after kidney transplantation for glomerulonephritis. INVESTIGATIONS: Clinical examination revealed an endophthalmitis and chest X ray a left-sided lobar pulmonic infiltration. Computed tomography and magnetic resonance imaging examination performed because of recurrent petit-mal-convulsions demonstrated multiple intracranial infiltrations. Transoesophageal echocardiography revealed floating vegetations up to 8 mm in diameter predominantly attached to the aortic valve. A total of 39 consecutive blood cultures drawn during several days remained sterile. However, Nocardia asteroides (Biovar A1) was isolated from a small cutaneous tumor excised from the right thigh. TREATMENT AND COURSE: After initiation of a specific antibiotic treatment with imipenem/cilastatin (each 1 g three times daily), and doxycyclin (100 mg twice daily), computed tomography and magnetic resonance imaging showed a reduction in size and number of the intracranial infiltrations. Neurological symptoms were progressive despite maximal anticonvulsant therapy. The patient died 83 days after hospital admission from an epileptic state resistant to therapy. CONCLUSION: Though nocardiosis is still rare, it should early be included in the differential diagnosis of infections in immunocompromised patients to allow timely diagnosis and therapy.

Anti-Bacterial Agents↗
PubMed1996

Error patterns on the continuous performance test in non-medicated and medicated samples of children with and without ADHD: a meta-analytic review.

We systematically reviewed the patterns of Continuous Performance Test (CPT) errors of omission and commission exhibited by normal children and children with Attention Deficit and Hyperactivity Disorder (ADHD) under no drug, placebo and methylphenidate drug conditions. Findings from 26 studies were submitted to a meta-analytic procedure. In contrast to the contradictory findings of individual reports, our results revealed that children with ADHD made significantly more errors of omission and commission than normal children. As well, in children with ADHD and treated with methylphenidate, statistically significant reductions in the rate of both error types were noted. The effects of methylphenidate on the percentage of hits (i.e. 1 - omissions) were greater in experiments using shorter stimulus duration, smaller number of trials and higher probability of a target. Using Signal Detection Theory (SDT) parameters, we found that children with ADHD were less sensitive to the difference between targets and non-targets than their normal counterparts, while showing a comparable response bias. Similarly, the effects of methylphenidate were restricted to improving the sensitivity, while not affecting response bias, in both normal children and those with ADHD.

Attention↗
PubMed1996

[A Q-fever pneumonia epidemic in Dusseldorf].

There was an unusually high incidence of atypical pneumonias in the catchment area of the Rhine river near the university of Düsseldorf in July 1994 during a long period of hot and dry weather. The 18 patients described in this paper (5 women and 13 men) complained of sudden onset of fever up to over 40 degrees C, often associated with severe headache and dry cough. Almost all of these patients had previously been healthy and active and of young to middle age (average 38 years) without any bronchopulmonary anamnesis. Radiology revealed that all the patients had in most cases defined pulmonary infiltrates without any specific preference for a particular site. Serology was initially negative, but four weeks later the complement fixation reaction titre was positive for Coxiella burnetii antibodies in 14 patients (78%). All patients became symptom-free within a few days'time when treated with a combination of antibiotics which included doxycycline, whereas the infiltrates receded completely only after several weeks. The occurrence of pulmonary Q-fever in a large northern German conurbation had been rare at that time. Such epidemics, however, were also noted in Berlin (1992) and in Dortmund (1993). The epidemic reported in this article probably originated from one of the frequent flocks of sheep grazing along the banks of the Rhine river near Düsseldorf. The infections were probably acquired by inhalation of airborne organisms in infected aerosols derived from infected sheep, promoted by the long-term very hot and dry weather which was at the same time very windy, leading to an unusually extensive spreading of the pathogens throughout a very large infected aerosol area.

Adult↗
PubMed1995

[Acute myocardial ischemia in spontaneous coronary artery spasm].

AIM OF STUDY: To discover what factors indicate spontaneous coronary artery spasms as a cause of myocardial ischaemia. PATIENTS AND METHOD: In a retrospective analysis 15 of 1407 consecutive patients who had undergone coronary arteriography (six women and nine men; mean age 47 +/- 11 years) had acute ischaemia due to spontaneous coronary artery spasms. The clinical findings at the time of first investigation and during the follow-up period (mean of 29 [3-65] months) were evaluated. RESULTS: The most common risk factors were hypercholesterolaemia (> or = 200 mg/dl) in ten patients (66%) and heavy nicotine consumption > or = 20 cigarettes per day) in eight patients (55%). Of the patients with angina at rest nine had reversible ST elevations, six had terminal T negativity in the ECG and an increased incidence of ventricular arrhythmias (n = 6). At time of hospitalization ten patients had acute myocardial ischaemia and five had signs of acute myocardial infarction (maximal creatine kinase concentration: 121-2980 U/l). Acute coronary angiography revealed circumscribed coronary artery constriction, reversible with nitroglycerin, with stenosis of < 70% in five patients and of > or = 70% in six, as well as intermittent vessel occlusion in four patients. Angiography showed smooth coronary artery walls in almost all instances. Angiographic evidence of circumscribed arteriosclerotic lesion with maximally 50% narrowing was present in six patients. CONCLUSION: Especially in younger, male patients with hypercholesterolaemia and heavy smoking recurrent anginal pectoris at rest, with reversible ECG signs of myocardial ischaemia but without advanced coronary sclerosis, speaks for spontaneous coronary artery spasms as the cause.

Acute Disease↗
PubMed1995

[Cyclosporin in severe steroid-requiring bronchial asthma].

BASIC PROBLEM: Treatment of chronic severe bronchial asthma with corticosteroids is inadequate in a minority of patients and is often accompanied by considerable side effects. Additional specific immunosuppression appears to be therapeutically promising. PATIENTS AND TREATMENT: Three patients (2 women, aged 44 and 29, a man aged 57 years), all with chronic severe asthma requiring corticosteroids, were given cyclosporin (mean dose 1.8 mg/kg; serum level 72 +/- 35 ng/ml) additional to conventional bronchospasmolytic drugs for 9 to 20 months. COURSE: The frequency and intensity of asthmatic attacks markedly decreased in all three patients. The mean peak-flow measurements in the mornings before broncholysis had increased by 23% over the precyclosporin level of the calculated normal value. Peak flow variability improved by 13%. The mean one-second forced expiratory volume (FEV1) rose from 37 to 66% of the normal value (P < or = 0.05) and correlated with the serum cyclosporin level (correlation coefficient 0.58-0.97). The frequency of acute severe asthmatic attacks (FEV1 < or = 40%) requiring additional hospitalization with intravenous administration of glucocorticoids fell by 30%. The systemic corticosteroid maintenance dosage could be significantly reduced or the drug discontinued in two patients. CONCLUSION: These observations indicate that cyclosporin can be useful in the treatment of selected cases of chronic severe steroid-refractory asthma. Prospective studies are needed to judge its long-term efficacy.

Adult↗