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Biomedical subjects

R Hopf

Publications and source records attributed to R Hopf.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Pathophysiology of fat embolisms in orthopedics and traumatology].

It is well known that fat embolisms can occur after long bone fractures, and this has been feared for more than 100 years. Since 1970 fat embolisms have also been recognized in endoprosthetic surgery. The clinical manifestation was described as the fat embolism syndrome (FES) by Gurd in 1974. Based on reports in the literature and our own data, a concise pathophysiological model of the FES is presented in this paper. The increase in intramedullary pressure (IMP) in the long bones is the most decisive pathogenic factor for the development of an FES. Any long bone fracture, stabilization of fractures, or implantation of knee or hip endoprostheses can generate IMP peaks leading to bone marrow release into the circulation. Bone marrow itself is a tremendous stimulus for activation of the clotting system. As a result, hypercoagulation and venous stasis in the draining veins generate mixed macroemboli from the initial bone-marrow microemboli. Bone-marrow embolization of the lung in phase I leads to mechanical obstruction of pulmonary arteries. In phase II, release of local mediators, triggered by a systemic inflammatory response (SIR) of the lungs, causes damage to the pulmonary membranes. Disturbed gas exchange and respiratory insufficiency with possible cardiac and cerebral decompensation are the result. In most cases an FES may not be detected clinically, and any mild cardiorespiratory changes are treated easily with oxygen insufflation and usually disappear within 48 h. Of paramount importance for clinical manifestation of an FES are the quantity and duration of bone-marrow release and co-factors (cardiorespiratory compliance and perioperative stability of the patient). Patients with preexisting cardiorespiratory disease in combination with massive intraoperative bone-marrow release may even face a deadly FES event. Increased IMP causes local obstruction of cortical vessels with bone marrow. In combination with the damaged endosteal blood supply, avascular necrosis of the cortical bone occurs. During endoprosthetic procedures, mechanical-and mediator-triggered damage of the intima of big veins, in combination with venous stasis and hypercoagulation may be responsible for the high incidence of proximal thrombosis of femoral veins. As a delayed result of the disseminated intravascular coagulopathy, petechial bleeding in the trunk and subconjunctiva can be seen. A better understanding and recognition of the FES's pathophysiology may help to use prophylactic, diagnostic and therapeutical measures more effectively.

Blood Coagulation↗
PubMed1994

A noninvasive functional evaluation following peripheral nerve repair with electromyography in a rat model.

A new bipolar surface electrode array was designed and constructed for a noninvasive "closed" functional evaluation with electromyography following sciatic nerve transection in a rat model. This "closed" method was compared with a conventional one-shot "open" measurement. Nerve conduction velocity and distal latency were calculated. Data obtained from the recordings from different animals as well as from the same animal at different points in time yielded excellent reproducibilities. There is no difference in the mean values whether nerve conduction velocity and distal latency are obtained by "closed" or "open" measurements. Correlation was significant (p < 0.01; rNCV = 0.77, rDL = 0.63) between these two methods. The results lead to the conclusion that the noninvasive functional evaluation with the parameters of nerve conduction velocity and distal latency introduced in the present study could be employed as a reliable method for serial functional evaluations following nerve transection in a long-term study in a rat model.

Animals↗
PubMed1994

[Effect of the prostacyclin analog taprostene on ischemic ST-segment depression in the stress ECG of coronary patients].

Prostaglandins and prostacyclin are potent vasodilators with marked hemodynamic effects, i.e., both improve cardiac function and possibly cause myocardial ischemia. In order to assess the stable prostacyclin analogon taprostene (T) we first performed an open preliminary study with increasing T-doses (6.5-50 ng/kg/min) and, secondly a double-blind crossover study versus placebo to investigate its influence on ischemic ST-segment depression during exercise stress testing under continuous T-infusions of 25 ng/kg/min (in one case 12.5 ng/kg/min). Eleven of 12 normotensive male patients (age 40 to 60, mean 52.8 +/- 8.4 years) suffering from angiographically proven coronary heart disease and stable angina pectoris completed the study. T was well tolerated, even under increasing doses, and blood pressure and the ECG parameters did not change. The double-blind study revealed no variation in the extent of ischemic ST-segment depression when compared to placebo, and all other ECG parameters as well as the blood pressure remained unaffected. Thus, myocardial ischemia cannot be ruled out completely under T, but earlier clinical findings may be confirmed characterizing T as a marked cytoprotective agent and, to a less degree, as a potent vasodilator.

Adult↗
PubMed1994

[Angiography follow-up after transluminal angioplasty of coronary bypass grafts].

Between January 1979 and October 1991, percutaneous transluminal angioplasty of stenosed or occluded coronary bypass grafts was attempted 180 times in 146 patients (180 lesions in 157 bypass grafts); 6/157 grafts were internal mammary grafts. The procedure was successful in 129/157 grafts (82%) and in 151/180 lesions (84%). Failures occurred almost exclusively in recanalization attempts. Cardiac complications occurred in 4/146 patients (2.7%). Three patients developed an acute myocardial infarction, another patient died after acute occlusion of a native vessel dilated during the same procedure. In successful attempts the severity of stenosis was reduced from 87 +/- 10% to 33 +/- 15%. 113/129 successfully dilated grafts had at least one (mean 2.7) control angiogram. 54/113 (48%) showed recurrence after a mean follow up of 6 months. An additional 15 grafts showed late restenosis in a second control angiogram (mean follow-up 23 months). The total restenosis rate was 61%. Restenoses were dilated again one to six times (mean 1.9) with comparable success and recurrence rate. Two patients died during the sixth angioplasty. Finally, 32/129 (25%) grafts were occluded or presumably occluded, and 97/129 (75%) were angiographically confirmed open without restenosis. Thus, angioplasty of bypass grafts is an alternative to a repeat revascularization surgery. The acute results are comparable to the results of angioplasty in native coronary arteries. The restenosis rate is high. One has to be aware of late restenosis. Restenosis can be dilated repeatedly with a comparable success rate and with no significant increase in restenosis rate.

Adult↗
PubMed1993

[Life-threatening diarrhea in atypical course of legionellosis].

After eating a meal of poultry a 41-year-old man fell ill with severe diarrhoea, persistent high fever of around 39 degrees C, dehydration and somnolence. On admission to hospital physical examination was normal except for signs of dehydration. The blood count showed a leukocytosis (13,300/microliters) with 60% stab-form neutrophils. The erythrocyte sedimentation rate was raised to 49/82 mm. Also increased were the serum concentrations of creatinine (3.5 mg/dl), creatine kinase (179 U/l), lactate dehydrogenase (298 U/l) and C-reactive protein (16.8 mg/dl). Bacteriological and virological examinations of blood and stool were negative. A normal fluid and electrolyte balance was re-established. But as there was no improvement, ampicillin was administered, 2 g three times daily, then ciprofloxacin, 500 mg two times daily, and finally combined with metronidazole, 500 mg three times daily. Despite this treatment a chest radiograph on the tenth day revealed an infiltration in the left basal lung segment, and the legionella titre became positive at 1:2045. The antibiotic treatment was changed to 150 mg roxithromycin two times daily. The fever fell within 3 days and the diarrhoea stopped after 5 days. He was discharged free of symptoms after 24 days.

Adult↗
PubMed1993

Cardiovascular effects, pharmacokinetics, and converting enzyme inhibition of enalapril after morning versus evening administration.

The cardiovascular effects and pharmacokinetics of once-daily enalapril were studied after single-dose and subchronic treatment in eight patients with hypertension by use of ambulatory blood pressure monitoring. Enalapril, 10 mg, was given at either 7 AM or 7 PM in a randomized crossover design. In addition, inhibition of serum converting enzyme was studied. Subchronic treatment at 7 AM significantly reduced blood pressure during the day but was less effective at night. Subchronic dosing at 7 PM significantly further decreased nighttime blood pressure followed by a slow increase during the day, with no effect on elevated afternoon values. Peak concentrations of enalaprilat were found 3.5 hours (morning) and 5.6 hours (evening) after drug intake (p < 0.05), whereas peak effects occurred 7.4 hours (morning) and 12 hours (evening) after drug administration. In conclusion, 24-hour blood pressure profiles in patients with hypertension were significantly influenced by the time of enalapril dosing. Differences in effect profiles could not be attributed to similar changes in pharmacokinetics or to different time courses of angiotensin converting enzyme inhibition.

Adult↗
PubMed1992

[Drug therapy of hypertrophic cardiomyopathy].

INTRODUCTION: Hypertrophy of the myocardium occurring in hypertrophic cardiomyopathy (HCM) may affect different locations of the left ventricle. If the hypertrophy is sited in the region of the basal septum, obstruction of the left ventricular outflow tract (hypertrophic obstructive cardiomyopathy [HOCM]) occurs. characteristic of left ventricular function in HCM is hypercontractility and disordered diastolic relaxation. THERAPEUTIC APPROACHES: In the medical treatment of HCM, the calcium antagonists play a leading role. They improve relaxation and, through their negative inotropic effect, decrease the intraventricular gradient. Although beta-blockers reduce the gradient in outflow tract obstruction, they do not improve relaxation. In individual cases the use of diuretics and anti-arrhythmic agents may be necessary; in the case of atrial fibrillation the use of marcumar is recommended. CAUTIONARY REMARK: In the event of dental treatment or invasive diagnostic procedures being necessary, prophylactic measures against endocarditis should be initiated.

Adrenergic beta-Antagonists↗
PubMed1992

[Ventricular function in hypertrophic cardiomyopathy. Systolic and diastolic ventricular function].

BASIC CONSIDERATION: Hypertrophic cardiomyopathy is defined as a primary myocardial disease associated with a hypertrophic non-dilated left ventricle with no other heart or systemic disease that might lead to hypertrophy of the left ventricle. The leading symptoms are effort-associated angina and dyspnea, rapid fatigue, dizziness and syncope. MAIN POINTS DISCUSSED: The hemodynamic situation is characterized by a hyperdynamic systole and impaired diastole and left-ventricular filling. In the obstructive form, hypertrophy of the basal septum and an anteriorly moving mitral valve during systole result in an end-systolic reduction in the cross-section of the outflow tract associated with considerable intraventricular pressure gradients. Disturbances in the myocardial calcium metabolism are presently suspected to be causally involved in the diastolic function impairment.

Cardiomyopathy, Hypertrophic↗
PubMed1992

Effect of propranolol and disopyramide on left ventricular function at rest and during exercise in hypertrophic cardiomyopathy.

In 19 patients with hypertrophic cardiomyopathy (15 males, 4 females, mean age 49.2 +/- 10.8 years) left ventricular function was studied with radionuclide ventriculography at rest and during exercise in a crossover design without intervention and after disopyramide and propranolol treatment. 15 of the 19 patients had a resting or latent intraventricular gradient of more than 30 mm Hg. Left ventricular function at rest and during exercise was evaluated before medication, 90 min after oral administration of 200 mg disopyramide or 160 mg propranolol and after 3 weeks of oral therapy with disopyramide 200 mg 2 times a day or propranolol 80 mg 4 times a day. After long-term treatment with disopyramide, resting ejection fraction decreased from 72 +/- 12 to 69 +/- 14% (p less than 0.01) and peak ejection rate (PER) decreased from 3.46 +/- 135 to 3.24 +/- 65 end-diastolic volume (EDV).s-1 (p less than 0.01). Peak filling rate (PFR) at rest decreased from 3.01 +/- 0.8 to 2.77 +/- 0.63 EDV.s-1 (p less than 0.05). Time to peak filling rate (TPFR) at rest and during exercise after acute and chronic therapy did not change compared to control values. Acute and long-term administration of propranolol lead to a significant reduction in heart rate at rest and during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1991

[Course of dilatative hypertrophic cardiomyopathy].

Five patients with hypertrophic cardiomyopathy developed left-ventricular dilatation and congestive heart failure during an observation period of 16-29 years. In one patient cardiac transplantation had to be performed. The initial predominant symptoms of outflow-tract obstruction and diastolic dysfunction developed into progressive left-ventricular systolic failure. The question of whether this is a well-defined subgroup of patients with hypertrophic cardiomyopathy, or whether hypertrophic cardiomyopathy turns into a phase of left-ventricular dilatation and failure after some years remains to be elucidated by long-term studies.

Adult↗
PubMed1990

Is technetium-99 m-pyrophosphate scintigraphy valuable in the diagnosis of cardiac amyloidosis?

Amyloidosis is a systemic disease frequently involving the myocardium and leading to functional disturbances of the heart. Amyloidosis can mimic other cardiac diseases. A conclusive clinical diagnosis of cardiac involvement can only be made by a combination of different diagnostic methods. In 7 patients with myocardial amyloidosis we used a combined first-pass and static scintigraphy with technetium-99 m-pyrophosphate. There was only insignificant myocardial uptake of the tracer. The first-pass studies however revealed reduced systolic function in 4/7 patients and impaired diastolic function in 6/7 patients. Therefore, although cardiac amyloid could not be demonstrated in the static scintigraphy due to amyloid fibril amount and composition, myocardial functional abnormalities were seen in the first-pass study.

Amyloidosis↗
PubMed1990

Management of hypertrophic cardiomyopathy.

Therapy of hypertrophic cardiomyopathy aspires to reduce symptoms, increase exercise tolerance, retard or prevent disease progression, and improve prognosis. Medical treatment with calcium antagonists and suppression of rhythm disturbances with amiodarone seem to be most effective. In patients who show no improvement, surgical treatment must be considered.

Cardiomyopathy, Hypertrophic↗
PubMed1989

[Ischemic reaction in a young woman without coronary sclerosis: Bland-White-Garland syndrome].

A 39-year-old woman, with known mild mitral regurgitation, developed progressively more severe symptoms of angina, associated with an ischaemia response in the exercise electrocardiogram. Angiocardiography demonstrated an anomalous origin of the left coronary artery from the pulmonary artery (Bland-White-Garland syndrome). At operation an aortocoronary venous bypass graft was constructed; the patient has been without symptoms since and the exercise ECG is normal. As demonstrated by angiography, the previously marked dilatation of the right coronary artery had largely regressed and previously present collaterals to the left coronary artery were no longer visualized three months after operation. The described coronary artery anomaly, although rare, should be considered in a young patient with reproducible coronary artery ischaemia.

Adult↗
PubMed1989

[Piretanide in chronic and acute decompensated heart failure. Effect on hemodynamics and vasoactive hormones].

Eight patients with chronic heart failure classified as NYHA class II to III (group 1) and nine patients with acute decompensated heart failure classified as NYHA class IV (group 2) were treated with piretanide at a dosage of 12 mg administered intravenously. In both groups the level of prostaglandine PGE2 as well as plasma renine activity significantly increased prior to the onset of diuresis. The percentage increase was more pronounced in group 1 which had lower baseline values. With a time-lag, the norepinephrine plasma level also increased significantly. During the first 30 minutes there was only little effect on blood pressure, pulmonary artery pressure and cardiac output in patients with chronic heart failure (group 1). Only after 60 minutes there was a significant decrease in mean pulmonary artery pressure (from 39 +/- 17 to 33 +/- 18 mm Hg; p less than 0.05). In patients with acute decompensated heart failure (group 2) piretanide led to a significant reduction in mean pulmonary artery pressure (from 42 +/- 13 to 37 +/- 12 mm Hg; p less than 0.05) within 15 minutes after administration, i.e. even prior to the onset of diuresis. Thus, the administration of piretanide had a positive effect on hemodynamics in patients with chronic as well as in patients with acute decompensated heart failure. Significant improvement prior to diuresis onset, however, was only found in patients with acute decompensated heart failure. These effects may be explained by a stimulation of prostaglandines which promote vasodilation. They are increased by the diuresis.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1989

[Basic therapy of chronic heart failure with digitalis or diuretics?].

Sixteen patients in heart failure and sinus rhythm were, after a four-week treatment-free period, randomly assigned to receive, for four to six weeks, either a diuretic combination (hydrochlorothiazide + triamterene) or a digitalis glycoside. Subsequently the treatment was exchanged between the two groups. Without treatment nine patients were in stage II (New York Heart Association classification), seven in stage III. Pulmonary wedge pressure at rest was 27 +/- 14, on exercise 32 +/- 8 mm Hg, cardiac output 5.3 +/- 1.0 at rest and 7.8 +/- 2.3 l/min on exercise. Digitalis glycosides improved symptoms by one stage in three of 16 patients. All objective measures showed slight but not significant improvement. Diuretic treatment improved symptoms in five patients, while heart size and echocardiographically measured ventricular volume decreased slightly. Cardiac output decreased at rest, but not significantly, and on exercise not at all. Pulmonary arterial pressure (21 +/- 9 mm Hg), pulmonary wedge pressure (13 +/- 7 mm Hg) and pulmonary artery pressure on exercise (39 +/- 11 mm Hg) were significantly lower on diuretics than without treatment. The results support the primary use of diuretics in the treatment of chronic heart failure.

Aged↗
PubMed1989

[Diastolic ventricular function in hypertrophic, obstructive and non-obstructive cardiomyopathy--effect of gallopamil].

Left ventricular function was investigated by radionuclide ventriculography in 13 patients (11 male, two female) with hypertrophic cardiomyopathy, aged from 22-57 years (mean 45.5 years) at rest and during exercise. Ten patients had hypertrophic obstructive cardiomyopathy with maximal left ventricular outflow tract gradients of 64-290 mmHg (mean 147 mmHg). Left ventricular enddiastolic pressure of all patients ranged from 8-35 mmHg (mean 21 mmHg). Radionuclide ventriculography was performed without therapy, after acute application of a single oral dose of gallopamil (50 mg), and after longterm treatment for 3 weeks (50 mg tid). Ejection fraction at rest after single dose increased from 69.2% to 72.9% (p less than 0.02), peak ejection rate (PER) increased from 333.5 to 362.0/s (p less than 0.01) and peak filling rate (PFR) from 284.5 to 316.5/s (p less than 0.02). Under exercise single dose as well as longterm treatment led to a slight but significant shift in the ratio of PFR/PER (from 1.02 to 1.12 after single dose [p less than 0.04], and to 1.18 with longterm treatment [p less than 0.03]). There was no correlation between the individual response to gallopamil treatment and histopathological parameters such as hypertrophy or fibrosis. These data demonstrate that gallopamil in patients with hypertrophic cardiomyopathy leads to an improvement mainly in left ventricular diastolic function which appears to be most effective under exercise.

Adult↗
PubMed1989

[The anti-ischemic effect of isosorbide dinitrate alone and in combination with gallopamil and propranolol].

In 18 patients (17 male and 1 female, 40 to 63 years old) with coronary heart disease, a randomized double-blind study was carried out to investigate in comparison to placebo, the antiischemic effects of 5, 10 and 20 mg isosorbide dinitrate (ISDN) alone and in combination with gallopamil (G: 25 and 50 mg) or 80 mg propranolol (P: 80 mg) on the ischemic ST-segment-depression in standardized exercise ECGs. ST-depression following administration of ISDN alone was reduced significantly and dose-dependently: following 5 mg from 1.32 +/- 1.14 to 1.0 +/- 0.85 mm (-25.2%; p less than 0.05), 10 mg from 1.17 +/- 0.85 to 0.91 +/- 0.69 mm (-21.7% n.s.) and 20 mg from 1.19 +/- 0.5 to 0.52 +/- 0.57 mm (-53.6%; p less than 0.001). In combination with gallopamil (G: 25 and 50 mg) or propranolol (P) reduction of ST-depression was more pronounced: by 5 mg ISDN with 25 mg G from 1.32 +/- 1.14 to 0.7 +/- 0.71 mm (-46.4%; p less than 0.05), with 50 mg G from 1.32 +/- 1.14 to 0.8 +/- 0.83 mm (-38.8%; p less than 0.01), with 80 mg P from 1.32 +/- 1.14 to 0.28 +/- 0.35 mm (-79.5% p less than 0.01), by 10 mg ISDN combined with 25 mg G from 1.17 +/- 0.85 to 0.69 +/- 0.6 mm (-40.7%; p less than 0.05), with 50 mg G from 1.17 +/- 0.85 to 0.66 +/- 0.62 mm (-43.5%; p less than 0.05), with 80 mg P from 1.17 +/- 0.85 to 0.64 +/- 0.78 mm (-46.4%; p less than 0.01), and by 20 mg ISDN with 25 mg G from 1.19 +/- 0.5 to 0.42 +/- 0.43 mm (-62.6%; p less than 0.001), with 50 mg G from 1.19 +/- 0.5 to 0.39 +/- 0.45 mm (-65.2%; p less than 0.001) and with 80 mg P from 1.19 +/- 0.5 to 0.05 +/- 0.16 mm (-95.8%; p less than 0.001).

Adult↗