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Biomedical subjects

H Schicha

Publications and source records attributed to H Schicha.

At least 91 records · Page 5Linked to original sources
PubMed1999

Improvement of myocardial blood flow to ischemic regions by angiotensin-converting enzyme inhibition with quinaprilat IV: a study using [15O] water dobutamine stress positron emission tomography.

OBJECTIVES: This study was designed to analyze the effects of acute angiotensin-converting enzyme (ACE) inhibition on myocardial blood flow (MBF) in control and ischemic regions. BACKGROUND: Although animal studies indicate an improvement of MBF to ischemic regions after ACE inhibition, this effect has not been conclusively demonstrated in patients with coronary artery disease. METHODS: Myocardial blood flow was analyzed in ischemic and nonischemic regions of 10 symptomatic patients with coronary artery disease using repetitive [15O] water positron emission tomography at rest and during maximal dobutamine stress before and after ACE inhibition with quinaprilat 10 mg i.v. To exclude the possibility that repetitive ischemia may cause an increase in MBF, eight patients underwent the same protocol without quinaprilat (placebo patients). RESULTS: Rate pressure product in control and quinaprilat patients was comparable. In placebo patients, repetitive dobutamine stress did not change MBF to ischemic regions (1.41 +/- 0.17 during the first stress vs. 1.39 +/- 0.19 ml/min/g during the second stress, p = 0.93). In contrast, MBF in ischemic regions increased significantly after acute ACE inhibition with quinaprilat during repetitive dobutamine stress (1.10 +/- 0.13 vs. 1.69 +/- 0.17 ml/min/g, p < 0.015). Dobutamine coronary reserve in ischemic regions remained unchanged in placebo patients (1.07 +/- 0.11 vs. 1.10 +/- 0.16, p = 0.92), but increased significantly after quinaprilat (0.97 +/- 0.10 vs. 1.44 +/- 0.14, p < 0.002). Total coronary resistance decreased after ACE inhibition (123 +/- 19 vs. 71 +/- 10 mm Hg x min x g/ml, p < 0.02). CONCLUSIONS: Angiotensin-converting enzyme inhibition by quinaprilat significantly improves MBF to ischemic regions in patients with coronary artery disease.

Adult↗
PubMed1999

Radioiodine therapy and thyroid-associated orbitopathy: risk factors and preventive effects of glucocorticoids.

Whether or not thyroid-associated orbitopathy is exacerbated by radioiodine therapy is a matter of controversy. Several risk factors can be listed: pre-existing active ophthalmopathy, hypothyroidism following radioiodine therapy, elevated T3 levels during radioiodine therapy, recurrent or persisting hyperthyroidism after low-dose radioiodine therapy and smoking. Recent studies and own data demonstrate that worsening of pre-existing thyroid-associated orbitopathy after radioiodine therapy can be prevented by the administration of glucocorticoids. Even in patients without evident ophthalmopathy the prophylactic use of glucocorticoids is in our opinion justified to minimize a small but known risk of the development of ocular symptoms. Larger prospective randomized studies are needed to establish the optimal dose and duration of the required anti-inflammatory therapy.

Disease Progression↗
PubMed1999

Positron emission tomography using 18F-fluorodeoxyglucose in advanced stages of malignant melanoma: a comparison of ultrasonographic and radiological methods of diagnosis.

The diagnostic and therapeutic impact and the cost-effectiveness of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) will depend on the role for which the tests are used. In 68 patients with advanced malignant melanoma, original sets of FDG-PET images from various institutes were compared with findings obtained by ultrasonography, conventional radiology, computed tomography (CT) and magnetic resonance imaging. In 22 patients, all examinations were undertaken within 2 weeks and strategies of staging were analysed. In 46 patients, only some of these examinations were performed within this time period, and comparison of methods was restricted to the examined organs. The occurrence of metastasis, without specifying the number of foci, was detected by either conventional staging with CT or by PET in 20 of 22 patients. None of these patients were up- or down-staged by FDG-PET compared with CT staging. In the 68 patients as a whole, FDG-PET detected fewer pulmonary and hepatic metastases and fewer cerebral foci, but more lymph node and bone metastases than conventional radiology or CT. For the detection of lymph node or skeletal metastases, false-positive FDG-PET findings were taken into account when compared with follow-up data. In advanced melanoma, FDG-PET did not influence the pattern of subsequent diagnostic testing. Thus, indications for FDG-PET include pre-metastatic melanoma, localized lymph node metastases and monitoring of the response to treatment.

Adolescent↗
PubMed1999

[Quality criteria for cost-benefit analysis in oncologic nuclear medicine and state of its realization].

Additional or expensive diagnostic imaging had to prove prospectively their diagnostic efficacy, their therapeutic efficacy, or their patient-outcome efficacy. The adherence to methodologic standards in the cost-effectiveness literature is required. Based on the bone scintigraphy in oncologic patients with a low prevalence of bone metastases, the cost-effectiveness is questionable. The economic role of 99m-Tc MIBI mammoscintigraphy and of the imaging for carcinomas of unknown origin is discussed controversially. Based on the reimbursement of the positron emission tomography (PET) in the USA and in Switzerland, cost-effectiveness literature and decision trees for cost-utility analyses are reviewed. PET imaging was cost-effective in non-small-cell lung cancer, in solitary pulmonary nodules, in recurrent colorectal cancer, in metastatic melanoma and in recurrent head and neck cancer with reduced costs of management. The German health insurance calls for PET-data based on the national reimbursement.

Breast Neoplasms↗
PubMed1999

[Two-step radioiodine therapy in benign thyroid diseases during a single hospital visit--observations on 100 patients].

AIM: A two-step radioiodine therapy (RITh) is occasionally necessary in patients with benign thyroid disorders, when strong differences to the pretherapeutic radioiodine test occur. In this study, the parameters (uptake and effective half-life of I-131) of the radioiodine test are compared with those of the first and second RITh. METHODS: 100 patients were evaluated, who received a two-step RITh in our department between June 1992 and March 1994. Uptake and effective half-life of I-131 and the absorbed dose in the first and second therapy were compared with each other based on the daily measured activity of the thyroid. RESULTS: A two-step RITh was necessary in 10% of the patients. The uptake of I-131 in the first RITh was significantly lower as compared to the test and significantly higher as compared to the second RITh. There were no significant changes between the effective half-life of I-131 in test, first and second RITh. CONCLUSION: The importance of radioiodine test for the calculation of therapeutic doses is emphasized. The data gathered in our study concerning the diminution of uptake of I-131 in the second RITh can be useful for dose calculation.

Adult↗
PubMed1999

[Synthesis of tumor affinity label Yb-169- and Y-90- porphyrin complexes and animal experimental investigations with various Yb-169-porphyrins].

AIM: It should be shown, that it is possible to insert radioactive isotopes of Yb and Y into some selected porphyrins. Besides, first informations about the biodistribution of Yb-169-por-phyrin-complexes should be obtained. METHODS: Carrier added radioactive isotopes were used for the synthesis of the metal porphyrin complexes. The animal experiments were done with mamma carcinoma bearing mice. The activity of the organs was determined 5 and 24 h after i.v. injection in a well counter. RESULTS: Four Yb-169-porphyrin complexes and Y-90-porphyrin complexes could be synthesized in non-carrier-free form. This was verified by absorption spectra, TLC and HPLC. Depending on the complex, the average tumour/background ratios were between 2 and 20. CONCLUSION: The synthesized radioactive metal-porphyrin complexes showed a clear tumour-affinity which could be used for tumour scintigraphy or perhaps therapy if the synthesis is improved (goal: reduction of carrier, other radionuclides).

Animals↗
PubMed1999

[F-18-FDG PET in autonomous goiter].

AIM: Gain-of-function mutations of the thyrotropin receptor (TSHR) gene have been invoked as one of the major causes of toxic thyroid adenomas. This study evaluates F-18-FDG-PET in these patients. METHODS: Twenty patients with focal autonomous nodules and ten with disseminated autonomy were investigated the day before radioiodine therapy. Twenty patients with cancer of the head or neck and normal thyroid function served as controls. RESULTS: F-18-FDG-Uptake was higher in patients than in controls. Focal autonomous nodules were associated with focally enhanced glucose metabolism. Disseminated autonomous goiters showed various patterns of focal or global hypermetabolism. CONCLUSION: Autonomous thyroid tissue caused by constitutive mutations of the TSH receptor is characterised by simultaneous increases in glucose and iodine metabolism which are correlated.

Adenoma↗
PubMed1999

[Cost-effectiveness analysis: radioiodine or antithyroid medication in primary treatment of immune hyperthyroidism].

AIM: As first-line therapy of hyperthyroidism caused by Graves' disease antithyroid drugs are favoured in Europe, while radioiodine therapy is favoured in the USA. Radioiodine therapy has become more economic in Germany since the new recommendations by the Federal German Radiation Protection Committee (SSK) for patient discharge guidelines. METHOD: Sensitivity analyses took into account the long-term relapse rate of conservative or radioiodine therapy, use of diagnostic tests, level of health insurance, drops in productivity and a discount factor. Costing models included the costs of follow-up care over 30 years. The costs of the hospitalisation for radioiodine therapy were calculated for 300 patients, discharged with 250 MBq 1-131 residual activity. RESULT: Antithyroid drugs were considered cost-effective when they achieved relapse rate of 50% or less, a cut in the number of tests needed and reduced working hours. Failure to meet any one of these conditions makes primary radioiodine therapy more cost-effective in 1593 of 1944 calculated costing models. Repeated conservative therapies will increase clearly the overall costs. CONCLUSION: Radioiodine is a cost-effective, first-line therapy in patients with a special risk of relapse after primary conservative therapy (goitre, younger patient, persistent elevated TSH-receptor-antibodies or Tc-uptake).

Antithyroid Agents↗
PubMed1998

Somatostatin receptor imaging in intracranial tumours.

The somatostatin analogue [111In-DTPA-d-Phe1]-octreotide (111In-octreotide) allows scintigraphic visualization of somatostatin receptor-expressing tissue. While it is well known that a large variety of tissues express somatostatin receptors and 111In-octreotide scintigraphy has a clearly defined role in various neuroendocrine diseases, the clinical value of 111In-octreotide scintigraphy in brain tumours is still under clinical investigation. In 124 patients with 141 brain lesions (63 meningiomas, 24 pituitary adenomas, 10 gliomas WHO class I and II, 12 gliomas WHO class III and IV, 11 neurinomas and 2 neurofibromas, 7 metastases and 12 other varieties: three non-Hodgkin B-cell lymphomas, two epidermoids, one abscess, one angioleiomyoma, one chordoma, one haemangiopericytoma, one osteosarcoma, one plasmacytoma and one pseudocyst), 111In-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 110-220 MBq 111In-octreotide. Planar images of the head in four views with a 128x128 matrix and single-photon emission tomographic images (64x64 matrix) were acquired, and lesions were graded according to qualitative tracer uptake. Fifty-nine of the 63 meningiomas showed moderate to intense tracer uptake. Nine of 24 pituitary adenomas were visible; the remaining 15 did not show any tracer uptake. None of the class I and II gliomas with an intact blood-brain barrier were detected whereas 11/12 class III and IV gliomas showed 111In-octreotide uptake. None of the neurinomas or neurofibromas were positive. Five of seven metastases were classified as positive, as were the osteosarcoma, two of three non-Hodgkin B-cell lymphomas, one abscess, one angioleiomyoma, one chordoma and one haemangiopericytoma. The other varieties (one non-Hodgkin B-cell lymphoma, two epidermoids, one plasmacytoma and one pseudocyst) did not show 111In-octreotide uptake. The results demonstrate that a large variety of intracranial lesions express somatostatin receptors and therefore can be visualized by [111In-DTPA-d-Phe1]-octreotide scintigraphy. This technique can be valuable in the differentiation between meningiomas and pituitary adenomas, based on qualitative tracer uptake. [111In-DTPA-d-Phe1]-octreotide scintigraphy allows differentiation between meningiomas and neurinomas or neurofibromas and therefore provides complementary information to computed tomography or magnetic resonance imaging. Furthermore, this technique allows differentiation between scar tissue and recurrent meningiomas postoperatively and can help in non-invasive tumour differentiation of multiple intracranial lesions, which can be of value in defining the most adequate therapeutic strategy.

Adolescent↗