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Biomedical subjects

G Schröter

Publications and source records attributed to G Schröter.

At least 19 recordsLinked to original sources
PubMed2000

Myocardial high-energy phosphate metabolism is altered after treatment with anthracycline in childhood.

OBJECTIVES: We aimed to investigate whether changes in high-energy phosphate metabolism after treatment of children and young adults with anthracycline can be demonstrated non-invasively by 31P magnetic resonance spectroscopy. BACKGROUND: Abnormal myocardial energy metabolism has been suggested as a mechanism for anthracycline-induced cardiotoxicity. Deterioration in such has been shown in animal studies by resonance spectroscopy. METHODS: We studied 62 patients, with a mean age of 13.5+/-5 years, 3.7+/-4.3 years after a cumulative anthracycline dose of 270+/-137 mg/m2. Normal echocardiographic findings had been elicited in 54 patients. The control group consisted of 28 healthy subjects aged 20+/-7 years. Resonance spectrums of the anterior left ventricular myocardium were obtained at 1.5 Tesla using an image-selected in vivo spectroscopy localization technique. RESULTS: The ratio of phosphocreatine to adenosine triphosphate after blood correction was 1.09+/-0.43 for the patients, and 1.36+/-0.36 (mean+/-SD) for controls (p=0.005), with a significantly reduced mean ratio even in the subgroup of patients with normal echocardiographic results (1.11+/-0.44 versus 1.36+/-0.36, p=0.01). The ratio did not correlate with the cumulative dose of anthracycline. The ratio of phosphodiester to adenosine triphosphate was similar in patients and controls (0.90+/-0.56 versus 0.88+/-0.62). CONCLUSIONS: In patients treated with anthracyclines in childhood, myocardial high-energy phosphate metabolism may be impaired even in the absence of cardiomyopathy. Our data support the concept that anthracycline-induced cardiotoxicity is not clearly dose dependent.

Adenosine Triphosphate↗
PubMed1997

Myocardial technetium-99m-tetrofosmin and technetium-99m-sestamibi kinetics in normal subjects and patients with coronary artery disease.

UNLABELLED: This study was designed to compare the tracer kinetics between 99mTc-sestamibi and 99mTc-tetrofosmin in a heterogeneous group of 24 patients admitted for routine perfusion imaging. METHODS: Twelve patients were studied with 99mTc-tetrofosmin and 12 with 99mTc-sestamibi. In each group, six patients had a low likelihood for coronary artery disease, and six patients had angiographically proven coronary artery stenoses of > 75% or previous myocardial infarction. Analysis of myocardial and liver uptake and clearance as well as target-to-organ contrasts were performed with planar stress images. RESULTS: Myocardial uptake of 99mTc-tetrofosmin was higher from 5 min (0.37 +/- 0.12 counts/pixel x MBq-1, p = 0.008) to 60 min (0.32 +/- 0.10 counts/pixel x MBq-1, p = 0.04) compared to 99mTc-sestamibi. Biological half-life for 99mTc-tetrofosmin (278 +/- 32 min) in normal myocardium was significantly shorter (p = 0.008) than for 99mTc-sestamibi (680 +/- 45 min). Biological liver half-life for 99mTc-tetrofosmin (67 +/- 16 min) was also significantly shorter (p = 0.02) than for 99mTc-sestamibi (136 +/- 18 min). Heart-to-lung ratios for 99mTc-tetrofosmin (2.49 +/- 0.43 at 5 min to 2.66 +/- 0.55 at 60 min) and 99mTc-sestamibi (2.52 +/- 0.37 at 5 min to 2.95 +/- 0.50 at 60 min) were similar. Whereas heart-to-liver ratios for 99mTc-tetrofosmin (1.04 +/- 0.24 at 5 min, increasing to 1.51 +/- 0.44 at 60 min) were significantly higher from 30-60 min postinjection (p = 0.05 at 30 min to p = 0.02 at 60 min) compared to the 99mTc-sestamibi (0.83 + 0.16 at 5 min to 1.08 +/- 0.27 at 60 min). CONCLUSION: Technetium-99m-tetrofosmin displays a shorter myocardial half-life compared to 99mTc-sestamibi. The rapid liver clearance of 99mTc-tetrofosmin, combined with comparable myocardial retention, resulted in higher heart-to-liver ratios but similar heart-to-lung contrasts compared to 99mTc-sestamibi from 30-60 min.

Coronary Disease↗
PubMed1996

A comparison of sevoflurane with halothane in outpatient adenotomy in children with mild upper respiratory tract infections.

STUDY OBJECTIVE: To investigate the efficacy and safety of sevoflurane compared with halothane in pediatric outpatient ear-nose-throat (ENT) surgery during the induction, maintenance, emergence, and recovery of anesthesia. DESIGN: Prospective, randomized, comparative, open-label study. SETTING: ENT operating room and postoperative recovery room at a university medical center. PATIENTS: 41 ASA status I and II children between the ages of 2 to 10 years, with mild upper respiratory tract infection (URI). INTERVENTIONS: Induction and maintenance of anesthesia with either sevoflurane or halothane for outpatient adenotomy, otomicroscopy, and myringotomy. MEASUREMENTS AND MAIN RESULTS: Induction (means +/- SEM) was significantly shorter in the sevoflurane group (2.6 +/- 0.2 minutes) than in the halothane group (3.2 +/- 0.2 minutes). There was no difference between the two groups with regard to complications that occurred during the induction and maintenance period. The time to emergence and recovery was significantly shorter with sevoflurane than with halothane (means +/- SEM; time to extubation 9.9 +/- 0.98 minutes vs. 13.4 +/- 1.06 minutes, time to eye opening 12.9 +/- 1.6 minutes vs. 24.5 +/- 1.8 minutes, command response time 20.7 +/- 2.5 minutes vs. 36.4 +/- 2.8 minutes). No difference in the incidence of complications during emergence and recovery was found. Evaluation of recovery as assessed by a modified Aldrete score showed that children who had received sevoflurane reached higher scores in the first 30 minutes following the discontinuation of the anesthetic. The Pain/Discomfort Scale demonstrated a difference in the sevoflurane group, with more children being agitated and restless. CONCLUSION: Sevoflurane provides a safe and rapid anesthetic induction with no differences in complications during the induction, maintenance, and emergence period. With sevoflurane, the time of emergence and recovery was significantly shorter. The characteristics of sevoflurane as evaluated in the present study make it a suitable anesthetic in pediatric outpatient surgery even in the presence of mild URI.

Adenoids↗
PubMed1994

Beneficial effects of a single dose of quinapril on left ventricular performance in chronic mitral regurgitation.

To evaluate the effect of a single dose of the angiotensin-converting enzyme inhibitor quinapril on left ventricular (LV) performance and size in patients with moderate to severe chronic mitral regurgitation (MR), 12 patients with angiographically proven isolated MR grade II to III and no evidence of coronary artery disease were studied. In all patients a baseline right heart catheterization and simultaneous radionuclide angiogram were performed at rest and during supine exercise (maximum 100 W) as well as 2 hours after oral administration of 10 mg of quinapril. Quinapril reduced heart rate slightly and lowered mean blood pressure at rest and during maximal exercise (p < 0.05). Systemic vascular resistance at rest was decreased from 1,484 +/- 505 to 1,150 +/- 427 dynes s cm-5 and with maximal exercise from 999 +/- 455 to 734 +/- 395 dynes s cm-5 (p < 0.005). Pulmonary capillary arterial pressure at rest decreased from 13 +/- 6 to 10 +/- 4 mm Hg (p = 0.01) and during maximal exercise from 29 +/- 10 to 20 +/- 7 mm Hg (p = 0.001). LV end-diastolic volume at rest (146 +/- 26 ml/m2) decreased after administration of quinapril to 128 +/- 24 ml/m2 (p = 0.001) and was also reduced during exercise (p = 0.001). LV end-systolic volume decreased from 63 +/- 43 to 49 +/- 35 ml/m2 at rest (p = 0.001) and with maximal exercise from 56 +/- 49 to 44 +/- 39 ml/m2 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Quinapril therapy in patients with chronic mitral regurgitation.

Pre- and afterload reduction is known to have beneficial effects in patients with chronic mitral regurgitation. To date, no controlled study has been reported analyzing the long term influence of angiotensin-converting enzyme inhibitor treatment on patients with chronic mitral regurgitation. Therefore the aim of this study was to assess the effects of one year angiotensin-converting enzyme inhibition with quinapril on myocardial performance in patients with chronic mitral regurgitation. Twelve patients with moderate to severe isolated chronic mitral regurgitation and no coronary disease on coronary angiography were studied under control conditions and followed up until one year of quinapril therapy (10-20mg/day) using echocardiography and simultaneous right heart catheterization, and radionuclide ventriculography at rest and exercise. As the result of a significant pre- and afterload reduction after one year quinapril treatment regurgitant fraction fell from 0.43 +/- 0.10 at control before therapy to 0.25 +/- 0.08 (p = 0.0001), left ventricular end-diastolic volume was reduced from 146 +/- 26 to 109 +/- 24 ml/m2 (p = 0.0001) and end-systolic volume decreased from 63 +/- 43 to 47 +/- 29 ml/m2 (p = 0.02). Left ventricular ejection fraction at control averaged 0.59 +/- 0.20 at rest, increased to 0.65 +/- 0.21 with maximum exercise and was unchanged after one year quinapril therapy. After one year treatment left ventricular mass was reduced by 15% (p = 0.0004) and septal wall thickness decreased from 11.8 +/- 0.7 to 10.8 +/- 0.8 mm (p = 0.0006). Moreover, there was significant functional improvement of nearly one NYHA class after one year quinapril therapy. In conclusion, in patients with chronic mitral regurgitation long term angiotensin-converting enzyme inhibition with quinapril reduces regurgitation and decreases left ventricular size and mass thereby demonstrating functional improvement. In addition, these data suggest that angiotensin-converting enzyme inhibition might have the potential of delaying mitral valve surgery.

Adult↗
PubMed1994

Assessment of tissue viability with fluorine-18-fluoro-2-deoxyglucose (FDG) and carbon-11-acetate PET imaging.

Positron emission tomography allows noninvasive assessment of myocardial metabolic processes and perfusion. Myocardial F-18-2 deoxyglucose (FDG) uptake as assessed by PET imaging has been established as a metabolic tracer indicating myocardial viability, whereas N-13 ammonia uptake reflects myocardial perfusion. Furthermore, it has been shown that the clearance of C-11-acetate in normal and ischemic myocardium correlates closely with overall myocardial oxygen consumption (MVO2). Therefore, C-11-acetate PET imaging has been proposed as a tracer for myocardial viability. In contrast with myocardial FDG uptake, the clearance of C-11-acetate is independent from overall substrate utilization. In the present time the highly expensive PET studies should only be performed in patients with chronic advanced coronary artery disease resulting in severely impaired left ventricular function. Moreover, coronary anatomy has to be suitable for revascularization and there has to be an absence of reversible perfusion abnormalities on Tl-201-chloride reinjection SPECT scans. This review focuses on clinical studies employing C-11-acetate and FDG PET imaging in patients with advanced chronic coronary artery disease, acute myocardial infarction and after heart transplantation. Clinical applications of FDG and C-11-acetate PET imaging and prognosis of PET flow-metabolic imaging regarding recovery of myocardial function and clinical outcome after revascularization and thrombolytic therapy are summarized. Furthermore, PET results are compared to SPECT imaging with Tl-201 and Tc-99m-MIBI.

Blood Glucose↗
PubMed1991

Frequency and spectrum of microorganisms isolated from biopsy specimens in chronic colitis.

In 109 patients with chronic diarrhea colonic biopsies were examined for the presence of specific microorganisms. A positive result was obtained in 48% of patients with ulcerative colitis, 50% with Crohn's disease, 21% with non-specific colitis and 36% with non-specific proctitis. Chlamydiae were found most frequently in all groups. Obligate enteropathogenic bacteria were isolated in only three cases of nonspecific colitis. Of the facultatively enteropathogenic organisms Klebsiella and Pseudomonas aeruginosa were isolated in 31% and 24%, respectively, of patients with ulcerative colitis, in 21% and 7% of patients with Crohn's disease, and in 10% and 6% of patients with non-specific colitis. Whereas chlamydial proctitis is a well-known disease, the results of this study point also to a possible pathogenic role of chlamydiae in the proximal colon. Facultatively enteropathogenic organisms causing acute diarrhea might have aetiologic relevance in some cases of chronic non-specific colitis.

Adolescent↗
PubMed1991

[Bacterial spondylitis caused by Haemophilus aphrophilus].

Four weeks after a slight scratch a 43-year-old man noted a severe back pain. Physical examination gave suspicion of a bacterial spondylitis. From the biopsy of the involved vertebral body Haemophilus aphrophilus was isolated under aerobic growth conditions.

Adult↗
PubMed1990

Rectal pseudotumor due to Chlamydia trachomatis in a male homosexual.

Chlamydia trachomatis causes a wide spectrum of human genital infections including lymphogranuloma venereum. We describe an unusual case of Chlamydia trachomatis proctitis in a homosexual man presenting with a large, solid tumor in the distal rectum, which was treated successfully by long-term oral doxycycline therapy.

Adult↗
PubMed1988

[Successful antibiotic treatment of a pulmonary infection with Nocardia asteroides (biovariety A3)].

An open lung biopsy in a 67-year-old man revealed nocardiosis as the cause of a treatment-resistant pulmonary infection. His resistance had been weakened by a non-Hodgkin lymphoma, polychemotherapy and long-term steroid medication. The nocardiosis was cured by a 26-day high-dosage regimen of imipenem and amikacin in combination. A six-month period of co-trimoxazole followed to ensure treatment success. Nocardia asteroides (biovariety A3) was found to be the causative organism, the second time that this has been described as cause of a human infection.

Aged↗
PubMed1987

[Immune depression as a reaction to surgical operations--its significance for postoperative infection].

Injuries, burns, and surgical intervention may lead to temporary depression of immune defence. Today, life-threatening infections may be caused by bacteria, such as pseudomonas, bacteroids, serratia as well as by viruses, including cytomegaly virus, and yeasts. Severe infections of that kind may be countered by adequate nutrition, planned application of antibiotics or, in the future, by possible active substances against depression of the immunity system, such as interferone, interleucine, and prostaglandins. More attention should be given in surgery to control of immunological defence as well as to knowledge about immunological defence mechanisms. Immune defence has proved to play an important role not only in transplantation surgery but also in other major surgical interventions and in intensive therapy.

Antibody Formation↗