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Biomedical subjects

M Fischer

Publications and source records attributed to M Fischer.

At least 595 records · Page 33Linked to original sources
PubMed1986

[Adrenal gland scintigraphy].

The exact localization of adrenal lesions can be achieved by noninvasive procedures. Whereas radiological methods reflect morphological changes, scintigraphy of adrenal cortex and medulla depends on function. - Radiolabeled 6 beta-methyl-19-norcholesterol is used for adrenocortical scintigraphy in primary aldosteronism, Cushing's syndrome and hyperandrogenism. By dexamethasone suppression a correct classification of adrenocortical lesions by scintigraphy can be observed in about 89% with a specificity of 86%. 123-I- and 131-I-metaiodobenzylguanidine is used for specific scintigraphy of the adrenal medulla. This method is a safe and reliable method for localization of adrenal and extraadrenal pheochromocytomas.

19-Iodocholesterol↗
PubMed1986

Influence of beta-aminopropionitril on media hypertrophy and baroreceptor reflex in normotensive and hypertensive rats.

Experiments were performed to investigate the antihypertensive action of beta-aminopropionitril (BAPN) in normotensive and hypertensive rats and to elucidate the role of media hypertrophy and arterial wall distensibility on baroreceptor reflex and blood pressure (BP) regulation. Normotensive Wistar-Kyoto rats (WKY), DOCA-salt hypertensive WKY, and stroke-prone spontaneously hypertensive rats (SHRSP) were treated with BAPN (100 mg/kg per day, intraperitoneally) for 10 weeks. The respective control groups (n = 10 per group) received 0.9% NaC1 instead of BAPN. In BAPN-treated groups the BP of DOCA-salt WKY (145 versus 170 mmHg) and SHRSP (170 versus 208 mmHg) was lower than that of controls at the end of the treatment period. In BAPN-treated rats, the medial cross-sectional area was reduced, postmortem distensibility of vascular wall was greater, and baroreceptor reflex, estimated from heart rate responses to BP changes, showed steeper regression curves. The BAPN-induced BP decrease in the hypertensive rats demonstrates that the level of sensitivity of the baroreceptor reflex is related to the mechanical properties of the arterial wall.

Aminopropionitrile↗
PubMed1986

Radioimmunoscintigraphy with anti-thyroglobulin monoclonal antibodies.

Monoclonal mouse antibodies to human thyroglobulin were conjugated to the cyclic dianhydride of DTPA. After radiolabelling with 111In this compound was injected into nude mice bearing various human thyroid carcinomas. Repeated imaging studies were carried out 15 min to 50 h after tracer administration. In both papillary and undifferentiated thyroid carcinoma no significant uptake of radiolabelled anti-hTG-MAb was observed.

Animals↗
PubMed1985

[Critical assessment of light reflection rheography. Comparative studies of phlebodynamometry using invasive measurement of venous pressure, photoplethysmography and light reflection rheography].

In chronic venous insufficiency, phlebodynamometry by invasive venous-pressure measurement demonstrates a reduced pressure drop and an accelerated pressure rise, resulting from the action of the ankle-joint-calf muscle "pump". On the other hand, light-reflexion rheography and photoplethysmography can measure only the duration of the refilling period. Simultaneous measurements were made on 47 legs after phlebography (normal: 8; side-arm varicosities: 17; long-saphenous insufficiency: 15; postthrombotic syndrome: 7). Refilling time by photoplethysmography correlated better with that measured invasively than by light-reflexion rheography. Refilling half-time cannot be measured accurately with either noninvasive method. Sclerosing treatment of single side-branch varicosities in ten legs demonstrated that merely measuring refilling time (invasively or noninvasively) was not sufficient, because this value did not indicate any improvement in haemodynamics even after successful treatment.

Adult↗
PubMed1985

The behaviour of the tissue pO2 in transparent chambers of rats with and without tumour implantations.

Changes of tissue pO2 levels in chronic subcutis wounds with and without heteroplastic tumour spheroid implants in thoraco-lumbal rat skinfolds covered by transparent chambers were followed in crosscut analysis by pO2 surface electrodes as a function of post-operative age using constant normoxic, hypoxic, post-hypoxic breathing conditions and intervals for each measured area. The tissue pO2 showed significantly higher values in the edematous phase of wound healing than in the granulation and differentiation phase. Tumour implantations induced even higher pO2 values in the edematic phase. This difference vanished in later phases. The hypoxic reactivity of non-tumour and tumour tissue improved with post-operative age indicating a sufficient vessel outgrowth.

Age Factors↗
PubMed1985

Effect of alpha-isopropylmalate on the synthesis of RNA and protein in Neurospora.

The leu-3/alpha-IPM (alpha-isopropylmalate) regulatory system, previously shown to control several genes of leucine, isoleucine, valine, and histidine biosynthesis, appears likely to be involved also in the regulation of overall RNA and protein synthesis in Neurospora. Upon addition of alpha-IPM the synthesis of all major species of stable RNA was found to be transiently inhibited by approximately 50%. A similar reduction was observed in overall protein synthesis. The inhibition was dependent in both cases on a functional leu-3 gene product, in conformance with previously established patterns of alpha-IPM dependent gene regulation. The overt resemblance of the phenomenon described here to the 'stringent response' of bacteria is noted but neither the mechanism of inhibition nor the precise role of alpha-IPM in the process has been established.

Adenosine↗
PubMed1985

Doppler frequency spectrum analysis and digital subtraction angiography in carotid artery disease.

The aim of the study was to evaluate the diagnostic accuracy of frequency spectrum analysis complementary to direct Doppler sonography in comparison to conventional biplane arteriography and transvenous digital subtraction angiography in internal carotid artery stenosis. In a group consisting of 229 carotid arteries visualized by conventional biplane arteriography, Doppler frequency spectrum analysis had a specificity of 97% and concerning all stenoses and occlusions, a sensitivity of 89%. In a second group consisting of 198 carotid arteries imaged by transvenous digital subtraction angiography, Doppler sonographic examination had a specificity of 65% only, and concerning all categories of stenoses and occlusions a sensitivity of 85%. These differences concerning specificity are not interpreted as false positive diagnoses in Doppler spectrum analysis but are considered to be due to false negative findings of digital subtraction angiography in stenoses of less than 50% vessel diameter reduction.

Carotid Artery Diseases↗
PubMed1985

[Peripheral venous DSA of the calf arteries in arterial obstructive disease patients. A comparison with conventional angiography].

The ability of venous DSA to demonstrate the calf vessels distal to the trifurcation in patients with proximal blocks was compared with conventional angiography in 33 patients (44 limbs) in a study carried out by four observers. In 11.1% cases, the vessels were demonstrated better by DSA and in 2.5% by conventional angiography. In 86.4% the quality was the same. The reasons for this are analysed.

Angiography↗
PubMed1985

The effects of dietary fibre in a liquid diet on bowel function of mentally retarded individuals.

A soy polysaccharide at a level of 20-22.3 g/day was added to a liquid formula diet provided to constipated, tube-fed, nonambulant, severely or profoundly mentally retarded individuals. This amount of polysaccharide contained 15.6-17.4 g of dietary fibre or 4.9-5.5 g of neutral detergent fibre. The fibre formula was well tolerated by the subjects and increased stool size and improved stool consistency. At these levels of fibre and short duration of the study, defecation rate and need for elimination aids were unaffected. Transit times of 5 to 6 days were unchanged but mean daily stool weights increased to a level equivalent to low normal values for healthy adults on a low fibre intake.

Adolescent↗
PubMed1985

Deficiency of fibrinogen and factor VII following treatment of severe aplastic anaemia with anti-thymocyte globulin and high-dose methylprednisolone.

In 4 patients with SAA treated with ATG and high-dose MP, an as yet unrecognized acquired deficiency of fibrinogen and factor VII was observed. The plasma level of fibrinogen fell to 39% (34-51%) and of factor VII:C to 50% (31-55%) of the pretreatment value. The nadirs were between days 10 and 35 (fibrinogen) and d 3 and 11 (factor VII) after the 1st dose of ATG/MP. From additional clotting studies it is concluded that disseminated intravascular coagulation, fibrinolysis, liver cell damage and synthesis of abnormal clotting factors are unlikely causes of these clotting abnormalities. The most probable explanation seems to be a selective inhibition of the synthesis of fibrinogen and factor VII by an as yet unknown mechanism. These clotting abnormalities might, to some extent, increase the bleeding tendency in these patients, which up to now had been solely attributed to thrombocytopenia.

Adult↗
PubMed1985

Primary aldosteronism: diagnosis and noninvasive lateralization procedures.

In 72 patients with primary aldosteronism who were classified on the basis of adrenal pathology after adrenalectomy, analysis of routine clinical and laboratory data, of supine and upright plasma aldosterone, and of plasma renin activity were of limited value in differentiating patients with aldosterone-producing adenoma(s) (APA, n = 59) from those with idiopathic adrenal hyperplasia (IAH, n = 13). Normokalemic aldosteronism occurred in 6 patients (3 APA, 3 IAH). A correct classification of the adrenal lesion(s) was obtained in 80% of the patients by computed tomography and only in 69% by adrenal scintiscan. In addition, adrenal scintiscan was hampered by a relatively high rate of incorrect results independent of whether dexamethasone was used or not. Small adenomas (less than 1 cm) and more often adrenal hyperplasia may escape visualization by computed tomography.

Adenoma↗
PubMed1985

Localization procedures in pheochromocytoma and neuroblastoma.

Localization procedures are required in catecholamine-producing tumors after clinical and biochemical confirmation. Computed tomography, ultrasound and/or 131I-metaiodobenzylguanidine (131I-MIBG) scintigraphy was performed in patients with pheochromocytoma, neuroblastoma and metastases of carcinoid tumors. Whereas computed tomography and ultrasound reflect morphological abnormalities, adrenomedullary scintigraphy depends on hormonal activity and other factors. 131I-MIBG scintigraphy has the advantage of detecting extraadrenal, multilocular and malignant pheochromocytomas. Especially small lesions and tumor tissue in bone marrow in children with neuroblastoma can be visualized more easily.

3-Iodobenzylguanidine↗