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Biomedical subjects

G Taubert

Publications and source records attributed to G Taubert.

At least 37 records · Page 2Linked to original sources
PubMed1990

Histological examination of blood vessels in peripheral gangrene among patients with sporadic outbreak of ergotism.

During the academic year 1985-1986 at Gondar College of Medical Sciences Hospital gangrenous ergotism was clinically diagnosed in seven patients (5 males, 2 females) ranging in age from 20 to 45 years. Amputation and subsequent histological examination of the blood vessels revealed occluded tibial arteries by acute thrombosis without cellular reaction or inflammatory lesion of the arterial wall in 3 patients. Endangitis with organized arterial thrombosis and focal recanalization of the vessels was noted in the remaining four patients. The smaller arterial branches including the dorsal pedal artery appeared to be contracted with knobby projections into the lumen. The latter was occluded by chronic, organized thrombosis in all patients. The present finding indicates that thrombosis and its organization could be another pathogenic factor in the development of gangrene due to ergotism, which is a histological picture similar to that of thrombangitis obliterans.

Adult↗
PubMed1989

Cytophotometric and interference microscopic investigations in carcinomas of the oral cavity.

The DNA content and the nuclear dry mass of 18 keratinized squamous cell carcinomas and their metastases, of one adamantinoma recurrence and two adenoid cystic carcinomas of the oral cavity were determined in comparison to the normal buccal mucosa using Feulgen scanning cytophotometry and interference microscopy. The squamous cell carcinomas could be classified into five groups based on their DNA distribution pattern. The nuclear dry mass and its variation were found to be different from the normal mucosal epithelial cells in all cases. No differences could be found between diploid cells and cells of a higher degree of ploidy. Therefore the relation of nuclear dry mass and DNA content appeared to be lower in cells of higher DNA ploidy. This fact is discussed in relation to the underlying molecular biological processes. This leads to the conclusion that the increase of the nuclear dry mass (mainly protein) precedes the increase of the DNA content. The combined measurement of DNA content and nuclear dry mass allows a better characterization of malignancy than each of the nuclear components measured alone. The difference of nuclear dry mass between malignant cells and normal mucosal epithelial cells is more sensitive than the deviation of the DNA content owing to the fact that malignant tumours with normal DNA content exist.

Carcinoma, Squamous Cell↗
PubMed1988

Flow cytometric DNA histograms and type of growth.

DNA histograms of human tumors should be interpreted together with the type of growth. In order to prove this connection the Ehrlich ascites tumors of 144 mice were investigated by absolute cell counting and flow cytometry. The exponential, transition and steady-state phases of tumor development were defined as types of growth based on the logistic function (Verhulst-Pearl). Flow-cytometric histograms (ethidium-bromide, olivomycin) were evaluated by two methods presupposing lognormal distribution and resulting in the same trend of changes concerning the percentage of cells in the three cell-cycle phases. In exponential growth the histograms show a high S-phase compartment and a decrease of the G2M peak. The increased percentage of S-phase cells is caused by a recruitment from G0-1 and G0-2 after transplantation. The decrease of the G2M peak is due to the exponential growth, a recruitment from G0-2 and a relative shortening of G2M duration. A high G2M peak and a low S-phase portion occur in steady state. Besides a decrease of DNA-synthesizing cells the S compartment decreases as a result of a relative S-phase shortening. For the increase of the G2M peak, transition into steady state, prolongation of G2M duration, recruitment of G0-1 and the occurrence of G0-2 cells are responsible. The same histogram may reflect different biological behavior patterns depending on the type of growth.

Animals↗
PubMed1988

Amyloid deposition in the nucleus basalis of Meynert complex: a topographic marker for degenerating cell clusters in Alzheimer's disease.

The deficiency of the cholinergic cortical projection system arising in the different basal forebrain structures collectively referred to as nucleus basalis of Meynert complex is a constant finding in Alzheimer's disease, a disorder which is neuro-pathologically characterised by the appearance of three intracerebral formes of twisted beta-pleated sheet (amyloid) fibrils, neurofibrillary tangles, amyloid-containing neuritic plaques and congophilic amyloid angiopathy. In the present study the quantitative relationship between these hallmarks of the disease, amyloid deposition and neuronal loss in the cholinergic basal forebrain system, was investigated in ten cases of Alzheimer's disease. Besides a constant involvement of the cerebral cortex and hippocampus, all cases of Alzheimer's disease show a large amount of amyloid in the medial septal nucleus, in the diagonal band nucleus and in the substantia innominata which is correlated with neuronal loss in these areas. These amyloid deposits in the basal forebrain are due to congophilic angiopathy associated with plaques and neurofibrillary tangles. The distribution of amyloid deposition in the basal forebrain is restricted entirely to those neuronal clusters which represent the origin of cholinergic innervation of the cerebral cortex and hippocampus. Immediately adjacent structures are not affected. These findings suggest a pathogenetic role of amyloid deposition in the mechanism of degeneration of the cholinergic basal forebrain system.

Aged↗
PubMed1987

Dry mass, DNA and non-histone protein determinations in lung cancer cells.

Cell nuclei from two biopsies of bronchial mucosa, seven squamous-cell carcinomas and six small-cell carcinomas of the lung were investigated. DNA and non-histone protein (NHP) content were simultaneously determined in Feulgen-Naphthol Yellow S-stained smears by means of multiple plug cytophotometry. In addition, the nuclear dry mass of cells originating from the same populations was measured by interference microscopy. DNA histograms of carcinomas were characterized by DNA stemlines being situated in the diploid range in four out of six small-cell carcinomas and in the hyperdiploid to hypertetraploid range in six out of seven squamous-cell carcinomas. Polyploid values (up to 8 c) were seldom found in small-cell carcinomas whereas squamous-cell carcinomas showed a broader dispersion approaching the 16 c level. The similarity of the NHP distributions with the DNA histograms was more marked in small-cell carcinomas than in the squamous-cell carcinomas. In comparison with the NHP distributions of normal bronchial epithelial cells, those of carcinomas were shifted to higher values. The increased NHP content was found to be a more prominent sign of malignancy in small-cell carcinomas than the DNA mass. The increase in nuclear dry mass in carcinomas was mainly caused by the accumulation of NHP in tumour cell nuclei.

Bronchi↗
PubMed1986

Hydrolysis optimum of TCA Feulgen reaction on lymphocytes, liver cells, and Ehrlich ascites tumour cells.

For simultaneous cytophotometric measurements of DNA and protein the Feulgen hydrolysis must be performed with trichloracetic acid (TCA) at room temperature because of the preservation of nuclear proteins. Already after 10 h of hydrolysis, a good discrimination between the frequency peaks in the histogram is obtained. The best results are achieved after a hydrolysis time in the range of the maximum of the hydrolysis curve (20 h). At this time, little variations of hydrolysis duration scarcely influence the cytophotometric data.

Animals↗
PubMed1986

Cell cycle peculiarities of the Ehrlich ascites tumour as revealed by cell counting and flow cytometry.

Based on own investigations general principles of cell cycle analysis by quantitative microscopic methods are discussed. Cell cycle peculiarities of the Ehrlich ascites tumour (EAT) are demonstrated. The numerical data yield information on the underlying type of growth expressed by the logistic function (Verhulst-Pearl). The effective tumour development starts with an exponential phase. In EAT the 5th day is regarded as representative for this stage. Then after a transition phase a steady state is reached. The 11th day after transplantation reflects best this phase of tumour development. By flow cytometric measurements DNA frequency distributions can be obtained in dependence of tumour age. The interpretation of the practically useful height of the second frequency peak in the histograms is discussed in relation to the underlying type of growth. The evaluation of the measurements reveals a characteristic change of the relative duration of the cell cycle phases G1, S, G2 and of the percentage of cells within these phases. Multiparameter single cell measurements complete the cytometric cell cycle analysis in relation to the position of cells in the cell cycle and allow a distinction between quiescent and proliferating cells. Finally the application of the parameters assayed on the biological model is extended to tumours in man.

Animals↗
PubMed1985

A new system to consider varying section thickness in histophotometry.

The reference material, an exposed and developed x-ray film, was cutted together with the tissue specimen. By scanning microscope photometry, the mean optical density of the silver layer was measured. By this way, variations in section thickness are to be considered for histophotometrical investigations. A good proportionality between the optical density of the silver grain layer and the relative thickness of the clear film carrier, estimated by microinterferometry, was proved.

Histological Techniques↗
PubMed1985

[Practical application of logistic function to the growth of experimental tumors].

The properties of the logistic law of growth (Verhulst-Pearl) and a simple method for computing of statistical approximation are described. Two parameters are estimated: the generation rate c and the mortality rate c0, although the real biological processes are of greater complexity. The logistic law is modified by an additional term concerning the prefinal decline in the last life span. To prove the curve fitting to tumour growth by the modified logistic function the total number of Ehrlich ascites tumour cells was measured in 144 mice at 12 different times after inoculation. The accuracy of the curve fitting proved to be very good. Therefore the logistic function modified by an additional term for the final stages, is particularly suited for the characterization of Ehrlich ascites tumour growth and its changes.

Animals↗
PubMed1983

[DNA content and sulfurous nuclear proteins of Ehrlich ascites tumor cells in relation to growth].

The proliferative behaviour of the Ehrlich ascites tumor in dependence on age after transplantation is characterized by pulse cytophotometrical DNA measurements as well as by determination of the sulfhydryl groups of the nuclear proteins. With increasing tumor age the DNA measurements show a decrease of the percentage of cells in S phase. During the first days of growth increases the percentage of cells in G1 phase. The percentage of cells in G2 and M phases increases strongly in the later days of growth. By the reaction of protein thiols with DDD and Fast Blue B cells with higher and lower concentration of SH groups of the nuclear proteins can be distinguished in two groups. By succeeding analysis of one and the same cell could be proved that the cells with higher SH concentration also possess a higher concentration of nuclear dry mass. On the basis of our own investigations and of data in the literature is suggested that the cells with higher nuclear SH concentration represent the visualized proliferating compartment of the tumor cell population.

Animals↗
PubMed1981

[Changed retinal cell content in diabetics (author's transl)].

A quantitative exploration of retinal cell content was carried out in diabetics and metabolically healthy controls of the same age and sex distribution. After diabetes of 6 years duration there was a drastic diminution of cells in the ganglion cell layer of the central retinal area, while the number of cells of the inner nuclear layer was slightly reduced and that of the outer nuclear layer was still unchanged. The periphery of short duration diabetic retinae showed a normal cell content in all nuclear layers. In long-term diabetes (about 10 years), significant diminutions in cell numbers were found in all layers of both the retinal center and periphery. The described cell deficits are accounted for by disturbances of retinal microcirculation. After a relatively short duration of diabetes, blood flow interruptions in the area supplied by the central retinal artery occur; in long-term diabetics the chorioidal vessels are also affected. Connexions between the cell-deficit pattern and functional (electrophysiological) findings are discussed.

Aged↗
PubMed1979

[Interference microscopic determinations of dry mass of cell nuclei of normal and dysplastic epithelium, carcinoma in situ and cervical carcinoma cultivated in vitro (author's transl)].

Dry mass of cell nuclei was studied in 34 explant cultures of normal epithelium (8), persisting dysplasias (7), Ca in situ (9) and cervical carcinomas (10) by interference microscopic determination. Dysplasias, Ca in situ and carcinomas can be distinguished from normal epithelium by a significantly higher dry mass value. Such a difference does not exist between dysplasia and Ca in situ. The percentage of dispersion of the dry mass is significantly higher in carcinomas than in all other examined tissues. The biological meaning of these results is discussed. The interference microscopic determination of dry mass of the cell nuclei is a suitable parameter for the characterization of properties of cervical carcinomas and their intraepithelial prestages cultivated in vitro.

Carcinoma, Squamous Cell↗
PubMed1978

Histophysical and histochemical investigations on muscle arterioles in hypertensive arteriolosclerosis; an interference microscopical, polarization optical and histophotometrical study.

In 50 formol fixed biopsies from the m. quadriceps femoris normal and hypertensive arteriolosclerotic arterioles were characterized by quantitative histophysical and histochemical methods. The interference microscopical measurements showed a real increase of dry mass concentration in the pathologically changed vessels. Additional histophotometrical results are interpreted as an increase of proteins with higher isoelectric point (globulins, actomyosin). An augmentation of actomyosin is compatible with the medial hyperplasia demonstrated histologically. Likewise a positive correlation was found between the fibrin incorporation proved histochemically and the quantitatively evaluated protein reaction with Fast green; Glycosaminglycans do not carry weight quantitatively. The polarization optical measurements yielded an alteration of the submicroscopical structure in arteriolosclerosis. It consists in a diminution of the submicroscopical volum of gaps and in a diminished orientated dye binding of Congo red. Thereby the pathogenesis of hypertensive arteriolosclerosis of skeleton muscle is above all characterized by an increase of heterogeneous proteins (blood plasma proteins, actomyosin) in the arteriolar wall, leading to a diminution of the submicroscopical volume of gaps and to an elevation of the dry mass concentration.

Arteries↗
PubMed1977

Renal biopsies performed on diabetics.

Metabolic disorders and immunological factors are discussed in connection with the pathogenesis of diabetic microangiopathy. Renal biopsies were obtained from 22 diabetics (8 women aged 18 to 53, 14 men aged 15 to 52). 7 of the 22 patients had been suffering from diabetes for 2 weeks to 3 years, 10 for 7 to 25 years, 2 showed a pathological glucose-tolerance test, i.e., they had been "latent" diabetics, and 3 patients, had been so-called "potential" subjects of diabetes due to hereditary traits or delivery of big babies. They were examined by light miroscopy as well as by immunofluorescence microscopy. A number of cases were chosen for the differentiation and counting of glomerular cells (n=8) as well as for electron microscopic (n=7) and polarizing-microscopic (n=6) examinations. Histologically, focal proliferations of mesangial cells as well as an increase in mesangial substance in the glomeruli was found in all cases, although in a varying degree of intensity. These results were confirmed by both the glomuerular cell count and electron-microscopic examination. Immunofluorescence microscopy made it possible to detect frequently both IgA (9/17) and IgG (9/17), usually in either linear or mesangial arrangements whereas it was less frequently possible to detect IgM (1/17) and albumin (1/8) and impossible to detect beta1C in the glomerulus. Labeled insulin was detected five times in the glomerulus. Polarizing-microscopic measurements made in order to discover possible submicroscopic variations in the structure of GBM showed deviations in the average values of anisotropic indices from the controls in the group of long-term diabetics only. The pathogenesis of diabetic microangiopathy may be described as an inflow of immunoglobulins and serum proteins into the mesangium because of an alteration of the capillary endothelium, the mesangial cell being thus caused to overfunction, proliferate and produce an excess of mesangial matrix. In prolonged diabetes the mesangial cell, so far as its own metabolism is concerned, will finally be affected to the point where its power of synthesis is modified in the sense of an excess and/or faulty composition of GBM (glomerular basement membrane).

Adolescent↗
PubMed1977

[On applicabilities of polarization microscopy in diagnostic histopathology (author's transl)].

Apart from its importance in ultrastructure research polarization microscopy turns out to be a valuable additional method in the daily hitological diagnostics of pathologist. By means of some examples the applicabilities of the polarization microscopy in this field are demonstrated. After some physical bases and practical hints for the use of polarization microscopes some staining reactions leading to an optical anisotropic effect are reported. Morever, it is reffered to the demonstration and characterization of crystals in biological fluids and tisdues. In our opinion, simple polarization optics should belong to the optical equipment of each pathologist.

Aorta↗
PubMed1976

[Passive electrical investigations on the normal and atherosclerotic human aorta in the alpha-dispersion area (author's transl)].

The passive electrical behaviour of the normal and the atherosclerotic human aorta was investigated at frequencies between 20 Hz and 50 kHz. A distinct alpha-dispersion area with characteristic frequencies of 280 and 104 Hz respectively was found in the normal vessel wall as well as in the atherosclerotic plaques. The confrontation of the passive electrical parameters determined from the curves shows in atherosclerotic plaques an increase of epsilon 0 and a decrease of epsilon infinity compared with the normal aorta. The characteristic frequency f 0 is smaller in atheromas and the relaxation time t 0 is larger accordingly. The distribution parameter alpha is smaller in atherosclerotic plaques. That means that in atheromas the physically defined structures are larger and among one another more similar physically. A connection between the passive electrical parameters and the structural and biochemical compisition of the vessel wall and its pathological changes is discussed.

Aged↗