Search PubMed⌕ Search

Biomedical subjects

R Montz

Publications and source records attributed to R Montz.

At least 73 records · Page 4Linked to original sources
PubMed1980

[Non-invasive method for recognition of coronary artery spasm: 201thallium sequential scintigraphy of the myocardium after ergotamine provocation (author's transl)].

For evaluation of coronary artery spasm 201thallium sequential scintigraphy of the myocardium after ergotamine provocation was performed in 10 patients with recurrent angina pectoris at rest and normal exercise ECG. In 9 out of the 10 patients ergotamine administration in the same dosage was repeated during the coronary angiography. A reversible defect in the 201thallium scintigram representative of regional myocardial ischaemia developed in 9 patients after ergotamine. Only in 4 out of the 9 patients angina pectoris and ST elevation were present at the same time. In all cases coronary spasm after ergotamine was demonstrable in the coronary angiogram; in the 4 patients with ergotamine-induced Prinzmetal angina pectoris it consisted of complete vascular occlusion, in the asymptomatic patients of incomplete vascular narrowing of a higher degree. In all cases the spasm could be relieved by ergotamine antidotes within a few minutes.

Adult↗
PubMed1980

Bone calcium exchange in primary hyperparathyroidism as measured by 47calcium kinetics.

A 2-compartmental analysis of 47Ca kinetics was carried out in 21 patients with primary hyperparathyroidism (pHPT) and 7 healthy control subjects. The results were compared with serum concentrations of calcium, inorganic phosphorus, alkaline phosphatase, and immunoreactive parathyroid hormone (iPTH). The well known increase in exchangeable calcium was found to be not uniform in its subcompartments and with a marked predominance of the osseous fraction. The most important result was the increase of calcium efflux from osseous into extraosseous exchangeable calcium in agreement with the results of Talmage et al. studying PTH actions on calcium flux rates between blood and bone in rats. The increased calcium efflux in pHPT was the only kinetic parameter correlated with serum iPTH. Neither increased calcium accretion indicating high bone turnover, nor serum calcium concentrations and exchangeable calcium fractions correlated with serum iPTH. These results lead to the following conclusions: radiocalcium kinetics provides valuable parameters of bone calcium turnover (osseous exchangeable calcium, bone-calcium efflux, and calcium accretion). Calcium efflux from exchangeable bone calcium, determined kinetically, might be related to PTH induced calcium transport from bone fluid compartment to extracellular fluids according to the concept of Talmage 1977.

Alkaline Phosphatase↗
PubMed1980

[Correlation between myocardial Thallium-201 kinetics, myocardial lactate metabolism and coronary angiographic findings in hypertrophic cardiomyopathy (author's transl)].

In 20 patients with idiopathic hypertrophic obstructive and nonobstructive cardiomyopathy (IHSS), biphasic Thallium-201 myocardial scintigraphy was performed. Regional myocardial Thallium-201 kinetics of these patients were analysed by a semiquantitative computerized method and compared with those of 6 normal subjects. In 12 of 18 with IHSS and no coronary artery disease 26 regions of interest with irreversible and 6 regions of interest with reversible Thallium-201 defects could be detected. Most of the Thallium-201 defects were localized in the interventricular septum. The defects were not related to the age of the patients and there was no relationship between the occurrence of reversible Thallium-201 defects and pathological myocardial lactate extraction rate during maximal atrial pacing measured in 14 patients. The percentage (6.8%) of irreversible defect regions in patients with LV outflow obstruction at rest (n = 13) was more than twice higher compared to those (n = 5, 3.2%) without LV outflow obstruction or no provocative pressure gradient, resp. These data suggest that IHSS is often associated with regional ischemic myocardial fibrosis despite normal coronary arteries. Therefore in these patients Thallium scintigraphy cannot be used as a noninvasive screening method to exclude or prove coronary artery disease.

Adult↗
PubMed1980

[Clinical correlations, lactate extraction, coronary venous bloodflow and Thallium-201 myocardial imaging in patients with isolated left anterior descending muscle bridges: normal variant or obstruction? (author's transl)].

In 848 coronary arteriograms performed in a two-years period 21 patients (2.5%) showed a myocardial bridging of the left anterior descending artery. Resting- and/or stress-ECG were abnormal in half of the patients. Regional lactate-metabolism measured in the great cardiac vein at rest and during maximal atrial pacing was normal (29 +/- 12 resp. 24 +/- 9%). Thermodilution of great cardiac vein bloodflow at rest and during atrial pacing also demonstrated normal values (94 +/- 33 resp. 138 +/- 30 ml/min). Biphasic 201-Thallium myocardial imaging revealed no case of reversible perfusion defect, but surprisingly frequent (5 of 16 patients) clearly irreversible defects limited to the interventricular septum. We conclude that muscle bridges do not cause myocardial ischemia at rest or during exercise.

Coronary Circulation↗
PubMed1979

[Spleen irradiation and splenectomy for treatment of hypersplenism in chronic myeloid leukemia and chronic lymphatic leukemia (author's transl)].

Hypersplenism is characterized by cytopenia, splenomegaly (possibly hyperplastic bone-marrow), and lienal hypersequestration. It is necessary, in view of the rather important surgical risks of splenectomy, to clarify if the hypersplenism may be influenced by splenic irradiation in case of chronic myeloid leukemia (CML) or chronic lymphatic leukemia (CLL). References in literature are rare and do not present a reliable differentiation of the syndrome, according to its present definition. Of our patients, three cases with hypersplenism verified by radioiron studies are reported: in one patient with chronic myeloid leukemia, irradiation of the spleen had no effect, whereas pancytopenia was completely repaired by means of splenectomy. The same results were seen in a patient with chronic lymphatic leukemia. In the last patient, however, who had chronic lymphatic leukemia, fractionated irradiation of the spleen led to a distinct improvement of anemia and thrombopenia, but the recovery lasted only six months. This effect is due to transient normalization of the lienal hypersequestration.

Aged↗
PubMed1978

[Reversible myocardial ischaemia or irreversible myocardial fibrosis? Differentiation by biphasic 201thallium scintigraphy (author's transl)].

The results of biphasic 201thallium (201Tl) scanning were compared with those of coronary arteriography, left ventricular angiogarphy and stress ECG in 56 patients with coronary artery disease and six with no evidence of heart disease. There were 104 201Tl defects, 50 of them reversible. The defects were always located in the area supplied by a critically stenotic coronary artery. Correlation of regional wall motion with 201Tl activity demonstrated that in all forms of abnormal wall motion there was either ischaemia or fibrosis. The resting LV angiogram thus does not make it possible to distinguish between myocardial ischaemia and fibrosis. Taking the LV angiogram as a standard, the rate of false-positive 201Tl scintigrams was 5%, that of false-negative ones 23%. The biphasic 201Tl scintigram was more sensitive than the stress ECG in detecting myocardial ischaemia. It furthermore made it possible to localize the ischaemic (or fibrotic) region within the LV and to estimate its size.

Adult↗
PubMed1978

Correlation of electron microscopic and secretory response of human parathyroid adenomas with different calcium concentrations in organ culture.

Twelve parathyroid chief cell adenomas from patients with primary hyperparathyroidism were incubated in a tissue culture system in the presence of different calcium concentrations and for various time periods. The endocrine response of the tissue was examined electron microscopically and radioimmunologically. After incubation in a medium of low calcium concentration the parathyroid adenomas showed ultrastructural signs of stimulation with proliferation of the hormone-synthesizing organelles. The development of the ultrastructural response could first be observed after four hours and increased up to several days. Radioimmunologically, an increase of the hormone secretion could be demonstrated. Converse results were obtained after incubation of the tumor tissue under suppressive culture conditions. To check for de-novo synthesis of the hormone released the tissue was incubated in a 75Se-methionine-containing medium. This resulted in radioactivity of the secreted parathyroid hormone, indicating de novo synthesis in our culture system. The biological potency of the released hormone was demonstrated by comparison of the PTH out of the medium with the international human MRC standard using two different radioassays.

Adenoma↗
PubMed1978

[Short-term localized myocardial ischaemia and its consequences in Prinzmetal angina pectoris (author's transl)].

In a 45-year-old female patient with Prinzmetal angina pectoris coronary angiograms and a 201thallium scintigram were performed during an ergotamine-induced episode of angina. The spontaneous and the ergotamine-induced attacks were characterized by transient ST elevation in the posterior wall ECG leads. The coronary angiogram during the attack showed spasm of the circumflex branch of the left coronary artery. In the 201thallium scintigram a large defect in myocardial thallium uptake was noticed in the posterior wall of the left ventricle. Angina and ECG abnormalities disappeared within 4 minutes. However, the scintigraphic defect disappeared only after 6 hours. The slow recovery of myocardial thallium uptake is thought to represent an alteration of the myocardium after a brief 4 minute interruption of regional coronary arterial blood flow. The diagnostic approach in patients with Prinzmetal angina is discussed.

Angina Pectoris↗
PubMed1978

[Diagnosis of primary hyperparathyroidism based on determination of parathormone in venous blood of the neck (author's transl)].

Experiences with 77 patients with primary hyperparathyroidism (HPT) are reported. Among the diagnostic parameters, the serum calcium level is the most significant; a definite diagnosis can be made through PTH-RIA. The problem of HPT diagnosis are discussed. For standardization, our own human PTH preparation, produced from tissue culture of operatively removed human adenoma of the parathyroid gland, has been used. For determination of parathormone, venous blood should be selectively extracted from the neck before every relapse-necessitated operation. The technically expensive and difficult examination methods do not excuse the surgeon from carefully exploring all of the parathyroid glands, though the general procedures to be applied before the first operation are still disputed.

Antigen-Antibody Complex↗
PubMed1977

The effect of calcium and dibutryl-cAMP on the secretion of parathyroid hormone by human parathyroid adenomas in organ culture.

The effect of different calcium concentrations as well as dibutyryl-cyclic adenosine 3',5'-monophosphate (DB-cAMP) on the secretion of parathyroid hormone by human parathyroid adenomas taken from patients with primary hyperparathyroidism (pHPT) was studied in organ culture. Their influence on the release of hormone was determined. The tissue was incubated in culture medium for 4 h; the medium was changed hourly and analyzed for immunoreactive parathyroid hormone (PTH) by radioimmunoassay. The hormone secretion showed an inverse relationship to different calcium concentrations in the medium and could be stimulated independently of the calcium concentration by adding DB-cAMP. These results suggest that the examined parathyroid adenomas are sensitive to physiological stimuli.

Adenoma↗
PubMed1977

The effect of 1,25-dihydroxycholecalciferol on the parathyroid hormone secretion of porcine parathyroid glands and human parathyroid adenomas in vitro.

The effect of 1,25-dihydroxycholecalciferol (1,25-(OH)2-D3) on parathyroid hormone secretion by porcine parathyroid glands and human parathyroid adenoma tissue was investigated by in vitro incubation. The addition of 100 nmoles 1,25-(OH)2-D3 to the medium inhibited significantly the release of immunoreactive parathyroid hormone by 63--65%. This suppression was reversible when 1,25-(OH)2-D3 was removed again. The inhibition of parathyroid hormone release observed in human parathyroid adenoma tissue was similar to that in normal porcine parathyroid glands. This indicates that adenoma tissue is sensitive to regulatory influences. As well as calcium, 1,25-(OH)2-D3 may act as another feedback inhibitor of parathyroid hormone secretion.

Adenoma↗
PubMed1977

[Resections of the pancreas: their effects on bone and calcium metabolism (author's transl)].

Four to ten years after partial or total resections of the pancreas calcium and bone metabolism was investigated. A high-turnover osteoporosis is proved by bone histomorphometry. There were no signs of osteomalacia or secondary hyperparathyroidism. Radiocalciumkinetics in all cases showed an increase endogenous fecal loss of calcium. Both, intestinal absorption and renal excretion of calcium were normal. Pathophysiologic relationship between resections of the pancreas and their influence on calcium and bone metabolism has not been sufficiently explained until now. Further investigation will be necessary.

Adult↗