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Biomedical subjects

H Frenzel

Publications and source records attributed to H Frenzel.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Dissolution processes and surface changes. 3. Determination of the surface with the BET process].

Two methods are demonstrated for the determination of the surfaces of solid substances by the BET-method. Using a newly constructed apparatus substances with high specific surfaces can be determined by the two-point-method with a good precision. For the determination of pulverous drugs we used the one-point-method proposed by Haul and Dümbgen [2] improving it in calibration und practicability.

Chemistry, Pharmaceutical↗
PubMed1985

[Light and electron microscopy findings in early and late stages of heart failure. Studies of endomyocardial biopsies of patients with latent (LCM) and dilated (DCM) cardiomyopathy].

Right-ventricular myocardial biopsies were obtained from 28 patients with LCM (EF 72 +/- 10.4%) and 36 patients with DCM of different degrees (EF 45 +/- 15%). Using paraffin sections and electron micrographs, 16 structural variables were semiquantitatively evaluated. Hypertrophy of myofibres, and nuclear and mitochondrial alterations were significantly more pronounced in patients with DCM. A score of 9 selected variables was found to be significantly higher in the DCM-group as compared with the LCM-group. The diameter of the myofibres was significantly thicker in DCM (17.5 +/- 2.2 microns) than in LCM (14.6 +/- 0.95 microns), but no significant difference of the volume density of myofibrils and of mitochondria could be determined. In the myocytes of DCM the mitochondria were significantly smaller than in LCM. The EF correlates with the myofibre thickness, with the semiquantitative score, and with the size of the mitochondria, but no significant correlation was seen with the volume density of myofibrils or mitochondria. The study has shown: At present no alterations in myocardial biopsies are known to be diagnostic for LCM or DCM. The findings support the concept of a diffuse myocardial disease in LCM. Only one patient out of 28 exhibited a myocardium without any pathologic changes. There is no evidence for small vessel disease in LCM. From the morphological point of view DCM and LCM are different only in quantity, but not in quality of their structural alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1985

[Dissolution processes and surface alteration. 4. Determination of the "effective" surface].

A method is described for measuring the "effective" surface of a drug by means of dissolution parameters using the Paddle-model or a resorption-model respectively. The obtained values were compared with the specific surface which was determined by BET-technique. The "effective" surfaces obtained by means of the dissolution parameters are smaller than those determined BET-technique.

Diffusion↗
PubMed1985

[Acute course of Leigh syndrome with hypertrophic cardiomyopathy in a female infant].

A female infant already as a newborn progressively developed nutritional disturbances, metabolic acidosis, muscular hypotension and other neurologic changes, and on its 20th day of life suffered from an acute cardiac and respiratory insufficiency due to pericardial effusions causing cardiac tamponade. In spite of intensive care including mechanical ventilation the child died on the 58th day of life. Cardiac changes and cranial CT-scans are demonstrated. The characteristic symptomatology as well as blood chemistry led to the tentative diagnosis of Leigh's disease. Postmortem examination confirmed this diagnosis.

Acidosis↗
PubMed1985

[The heart in the elderly. Light and electron microscopy findings].

No specific morphological substrate has yet been found which could explain the reduced adaptability of the heart in old age. A review is given of the most striking changes which have been observed in the myocardium of elderly humans and animals, as revealed by light and electron microscopy. Heart muscle cells: In the myocytes of aged animals an increase in fat droplets and glycogen was observed, but there was a reduction of endoplasmic reticulum. Basophilic degeneration, which is a frequent alteration of myocardial cells in old people, is based on the storage of a glucose polymer. The age-related increase of lipofuscin particles in myocytes is well known. In the course of life they change their structure from a fine granular type in children to a coarse granular and vacuolated type in the aged. The importance of this wear and tear pigment for myocardial function is not known, which is also true for the altered lipid composition of the cellular membrane of myocytes in the hearts of the elderly. A reduction of the mitochondrial to myofibrillar ratio, which was found in the left ventricular myocardium of old old rats, may affect the adaptability of the heart, and changes in the ratio of myosin isoenzymes are suggested to be of importance in reduced contractility. Studies on the mitochondria in the aged myocardium revealed different results concerning size and numbers.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

[Myocardial infarct--morphology and development].

Exact pathological investigations revealed 90% of transmural infarctions to be caused by thrombotic occlusion of "Infarction branch". This is the reason for and not the consequence of the myocardial infarction. The myogenic theory could be disproved for the overwhelming majority of cases. The subendocardial infarction is caused by stenosed three-vessel-disease occasionally combined with severe anemia or attacks of tachycardia. In about 30% of cases fibrinous pericarditis could be found over the infarction area. Mural thromboses were detected in about one third of the transmural infarctions, a myocardial rupture was found in 10 to 15% of autopsies. A ventricular aneurysm developed in 5 to 10% of those cases, who survived more than 3 months. In cases of sudden death a severe stenosis or occlusion of one or more coronary vessels were found in more than 80%. A fresh thrombotic occlusion was also found due to rupture of arteriosclerotic plaques. An infarction is in this condition often not detectable, because the time between the onset of the attack and death was too short to develop a myocardial necrosis.

Arrhythmias, Cardiac↗
PubMed1984

Congenital Leigh's disease: panencephalomyelopathy and peripheral neuropathy.

A dystrophic newborn girl (38th week of gestation) presented as a floppy infant with relapsing episodes of lactic acidosis and progressive cerebral deterioration. She died after serious apnoea at the age of 8 weeks. Neuropathological examination demonstrated widespread changes of Leigh's subacute polioencephalomyelopathy affecting the cerebral cortex, basal ganglia, mesencephalon and spinal cord. In addition, there was severe leukoencephalopathy of the cerebral hemispheres with sudanophilic tissue degregation, advanced axonal loss and reactive astrocytic gliosis. There was marked demyelination of the sciatic nerves. Electron-microscopical examination of the hypertrophic heart revealed pathological mitochondria with tubular inclusions suggestive of primary mitochondrial cardiomyopathy. Similar mitochondrial changes were not detected in the CNS and PNS. The complex of neuropathological alterations in this case is nevertheless consistent with a congenital variant of Leigh's disease.

Brain↗
PubMed1984

Age-dependent structural changes in the myocardium of rats. A quantitative light- and electron-microscopic study on the right and left chamber wall.

Myocardial fine structure of 6-week-old and 2-year-old female Wistar rats was examined after fixation by perfusion. Qualitatively, lipid droplets, lipofuscin granules and myelin figures were found more often in the older animals. Quantitatively, the volume density of the interstitium of the right ventricular myocardium had significantly increased (52%) in the 2-year-old rats. In these animals a reduction (9%) in the volume fraction of mitochondria in the left ventricular myocytes was seen, while the volume fraction of myofibrils had increased by 10%. The numerical density of mitochondria had significantly increased in the left ventricular myocardium of the older rats by 42%. A decrease in the average size of a mitochondrion by 36% could be shown in the left and by 11% in the right ventricular myocytes of the 2-year-old rats. In these animals the myofibrillar transverse diameter diminished by 15% in the left and by 6% in the right ventricular wall, while the number of myofibrils had increased by 36% and 12%, respectively; these findings signify a close relationship in the number of mitochondria and myofibrils in myocytes. Quantitative alterations in the myocytes of aged rats are more obvious in the left than in the right chamber wall. A reduced mitochondria/myofibril ratio may contribute to the diminished functional adaptability of the aging heart.

Aging↗
PubMed1983

Effect of chronic alcohol consumption on tumor incidence due to dimethylnitrosamine administration.

To study the effect of chronic alcohol consumption on tumor development due to dimethylnitrosamine (DMN) administration, female Sprague-Dawley rats were pair-fed for 3 weeks a nutritionally adequate liquid diet containing either ethanol (36% of total calories) or isocalorically substituted carbohydrates as control diet. Thereafter, the animals were maintained on laboratory chow and tap water ad libitum for another 2 weeks and received 1.5 mg DMN i.p. per day for the first 5 days. This 5-week cycle was repeated three more times. Chronic treatment with an alcohol-containing diet was shown to significantly improve the mean survival time of DMN-treated rats compared with identically treated animals fed the control diet, but the total number of tumors observed under these experimental conditions and the target organ remained virtually unchanged.

Alcoholism↗
PubMed1983

Patch-graft enlargement of the aortic root using autologous pericardium (long-term results).

In some clinical cases, mainly with severe aortic valve stenosis, there is a disproportion between the diameter of the aortic root and the adequate valve prosthesis for the patient. The resulting defect of the aorta requires a patch closure. The patch material mostly used is Dacron, but in our series autologous pericardium has been preferred. From 1970 to 1979 this procedure was performed in 28 out of 661 patients with aortic valve replacement (4.2%). Seven patients died postoperatively or during the follow-up period. In 1981 the surviving patients were restudied with particular reference to any complication resulting from the pericardial patch. The follow-up period was 15 months to 10 years with a mean of 4 years. Data of the postoperative reexaminations of 19 out of these 21 patients are available. No patient restudied demonstrated any sign of aortic aneurysmal dilatation or destruction, dissection, or perivalvular leakage in this particular area. Therefore autologous pericardium can be recommended as patch material to close a defect in the ascending aorta after aortic valve replacement.

Adolescent↗
PubMed1983

Differential diagnosis of hypertrophic cardiomyopathies: typical (subaortic) hypertrophic obstructive cardiomyopathy, atypical (mid-ventricular) hypertrophic obstructive cardiomyopathy and hypertrophic non-obstructive cardiomyopathy.

Previous clinical studies in patients with hypertrophic cardiomyopathies predominantly comprised patients with typical subaortic HOCM and in many other studies patients with 'hypertrophic' cardiomyopathies were investigated; i.e. no distinction was made between patients with the typical obstructive, the atypical obstructive and the non-obstructive forms of hypertrophic cardiomyopathy. In addition, in the more differentiated studies, the differential diagnosis between HOCM and HNCM was based mainly on the presence and absence of the subaortic pressure gradient. This is also true for the clinical characterization of both types of hypertrophic cardiomyopathy. Finally, diagnostic descriptions of atypical (mid-ventricular) HOCM exist only in the form of case reports, i.e. they are not based on observations in a large number of patients. Therefore a comparative study in 353 patients with hypertrophic cardiomyopathies was designed to characterize the clinical picture of patients with HNCM and with atypical HOCM in relation to typical HOCM with special reference to the differential diagnosis. The study revealed a profoundly different diagnostic profile of the three subsets of hypertrophic cardiomyopathies. The distinction between the three subsets may serve as a more differentiated basis for clinical studies related to diagnosis, therapeutic approaches, long-term follow-up observations and prognostic evaluation of patients with hypertrophic cardiomyopathies.

Adolescent↗
PubMed1983

Effect of an acute dose of ethanol on the hepatotoxicity due to carbon tetrachloride.

To study the effect of an acute dose of alcohol on the hepatotoxicity due to CCl4, rats received alcohol (4 g/kg BW) and/or CCl4 (1.5 ml/kg BW) by concomitant intragastric intubation. Compared to animals receiving CCl4 alone, the simultaneous application of CCl4 and alcohol resulted 12 h after administration in significantly lower serum activities of glutamate oxalacetate transaminase (1005 +/- 70 vs 739 +/- 47; p less than 0.01) and glutamate pyruvate transaminase (746 +/- 10 vs 330 +/- 41; p less than 0.01), whereas 36 h after administration, an increase of serum enzyme activities was observed. No significant differences could be demonstrated 24 h after application. By histological assessment, liver damage was also much less pronounced 12 h after combined administration of CCl4 and ethanol, compared to CCl4 alone, whereas the reversed constellation could be demonstrated 36 h after administration. These results therefore show that in the early phase of CCl4 intoxication an acute dose of alcohol may partially protect from CCl4 hepatotoxicity, whereas potentiation was observed under these experimental conditions in the late phase of CCl4 intoxication.

Alanine Transaminase↗
PubMed1983

[Global and regional computer-assisted functional topography of the thyroid. A simple self-calibrating method for supplementing gamma-camera-thyroid-gland scintigraphy].

A semiautomatic computer program is described for the quantification of global and regional 20 min 99mTc-thyroid uptake. The procedure is self-calibrating by the activity remaining in the empty syringe. The standardized definition of the thyroid ROI by an isocontour in the interpolative background corrected thyroid image results in an excellent inter-observer variability. The very short processing time of 30 sec makes this procedure suitable for routine use.

Calibration↗
PubMed1983

[Left ventricular basal fibrous myocardial aneurysm in a 3-week-old girl].

A congenital bulging of the myocardial wall is a rare finding; little is known about its etiology and clinical course. The case of a 3-week-old girl in whom rapidly progressive cardiac insufficiency occurred after a completely normal postnatal development is described. Selective ventricular angiography revealed ventricular malfunction and an akinetic area occupying 57% of the basal free left ventricular wall. The child died in acute cardiac failure. Autopsy disclosed a basal fibrous aneurysm which extended to 34% of the free ventricular wall. There was no indication of a coronary or inflammatory etiology, so a focal disorder of myocardial architecture was presumed. Congenital bulging of the ventricular wall can be divided into broad-based aneurysms and diverticula, the latter being connected with the ventricle by a small orificium. A further distinction can be made on the basis of localization and histology. A reclassification of the congenital bulging of the left ventricular wall presented in the literature showed that apical muscular diverticula are the most frequent, whereas only four cases of fibrous aneurysms were reported. Differences were found, with regard to the distribution of age and race, the clinical course, and the possible etiology.

Diagnosis, Differential↗
PubMed1983

[Unusual benign and malignant ureteral stenosis. Causes, therapy and clinical course].

In 652 patients with ureteral stenoses treated in the last 23 years we found 12 (1.8%) patients with rare benign and 5 (0.7%) patients with rare malignant diseases resulting in ureteral stenoses. Causes, clinical symptoms, diagnostic procedures and pathohistological findings are analysed and discussed with emphasis on the pathohistological diagnosis. Operative procedures are demonstrated and long term follow-up studies presented.

Adult↗