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Biomedical subjects

H Themann

Publications and source records attributed to H Themann.

At least 19 recordsLinked to original sources
PubMed1979

Ultrastructural morphometric investigations on human platelets after long-term ingestion of oral contraceptives.

Platelets from healthy females, who were taking oral contraceptives over a long period of time, were investigated by ultrastructural morphometry. The size, shape, relative volumes, numerical and surface densities of the platelets and their organelles were measured. In 'long-term pill users' the platelets showed a significant increase in the area of section profile. Further changes as, for example, increased volume of platelet granules, reduced number of mitochondria, decreased volume and surface of the open canalicular system, and increased surface of the dense tubular system are to be noted.

Adolescent↗
PubMed1979

Carbon tetrachloride induced proliferation of tight junctions in the rat liver as revealed by freeze-fracturing.

Application of carbon tetrachloride produced a progressive proliferation of tight junctions in the rat liver. This system proved to be rapid and highly reproducable and affords the opportunity for tracing the fate of tight junctions in freeze-fracture replicas, facilitating investigations on their formation and function. Beginning on day one carbon tetrachloride treatments resulted in the progressive loosening and fragmentation of the junctional meshwork. After three to four days the membrane outside the zonulae occludentes was extensively filled with proliferated discrete junctional elements often forming complex configurations. From the fifth day on the zonulae occludentes were restricted again predominantly around the bile canaliculus margins. But the junctional meshwork of the zonulae occludentes remained loosened in comparison to those in the control rats. It could be shown that tight junction proliferation on the lateral surface of the plasmalemma occurred both through de novo formation from discrete centers of growth by addition of intramembranous particles and through reorganization of preexistent junctional strands of the fragmented zonulae occludentes bodies. Whereas the large gap junctions close associated with the zonulae occludentes remained more or less unaffected during the experiments, small gap junctions increased in number after five days and were located at the margin or in the tight junction domain. It is assumed that the degeneration of the tight junctions served as a pool for intramembranous particles which form the gap junctions. The results of these observations are discussed in relation to those obtained in other systems.

Animals↗
PubMed1978

[Ultrastructural morphometric analysis of normally loaded human myocardial left ventricles from young and old patients (author's transl)].

An ultrastructural and morphometric analysis was performed on human myocardial left ventricle, obtained during surgical heart operations on normally loaded ventricles. The diagnoses of the patients were a) Persistant foramen ovale b) Atrial septal defect stage (I.-II) c) Mitral stenosis (stage III.-IV.). The median values of left ventricular pressure were not pathologically elevated. The patients were divided in 2 groups, the younger one ranging from 5-15 years, the older from 42-78 years. It was shown that the volume density of the interstitial tissue does not differ with the aging process. The number of the nuclei per test area of the heart muscle cells decreased within age (P less than 0.001). This finding suggests a decreasing process in the number of the heart muscle cells and an increase in size of the individual myocardial cell. Increase in the volume density of myofibrils was demonstrated at electron microscopical level with aging (P less than 0.02). The volume density of mitochondria is the same in both groups, whereas the volume density of the remaining cytoplasm (without myofibrils and mitochondria) decreases (P less than 0.05). The numberical density of the mitochondria increased in the older patient group (P less than 0.001).

Adolescent↗
PubMed1978

[Ultrastructural morphometric analysis of hypertrophied human myocardial left ventricles (author's transl)].

Biopsies of hypertrophied human myocardial left ventricles were investigated morphometrically. The diagnoses of the patients were stenosis of the aortic valve, aortic insufficiency or a combination of both lesions. The results were compared with those from normally loaded human left ventricles. There are no differences on light microscopical level between the volume densities of interstitial tissue and of heart muscle cells in the three groups of patients. A significant diminution of the volume density of the nuclei (P less than 0.001) and the number of nuclei per test area (P less than 0.001) when compared with normal groups suggests an increase in volume of the single heart muscle cell. The ultrastructural study shows marked increase in volume density of myofibrils (P less than 0.0001), with accompanying decrease in the volume densities of mitochondria (P less than 0.0001) and the remaining cytoplasm (P less than 0.001). A gross decrease in the surface area of mitochondria (P less than 0.001) and of cristae mitochondriales (P less than 0.0001) is found. The morphological equivalents of this result are numerous stages of mithochondrial destruction including cristolysis. All myocardial weights were beyond the "critical heart weight".

Adult↗
PubMed1978

Ultrastructural morphometric investigations on normal human platelets.

Platelets from normal human volunteers were investigated by ultrastructural morphometry. Preparation of blood samples was done in two different ways in order to evaluate the possible influence of the preparative method on the size and shape of platelets and their organelles. No significant differences could be dmonstrated for any of the measured parameters. Relative volumes of specific granules, mitochondria and the open canalicular system were calculated according to the method of Weibel. Surface and numerical densities of some compartments were determined. Direct measurements of the long and short axes of the platelets were conducted to ascertain further information about their size and shape. Absolute data are in good agreement with the few reports in the literature.

Blood Platelets↗
PubMed1978

Ultrastructural morphometric investigations on normal human liver biopsies.

Normal liver biopsies of 14 volunteers were investigated ultrastructural morphometrically. Besides the determination of morphometric baseline data for comparative purposes particular emphasis was placed on the question, if morphometric evaluations of human livers yield reliable results in spite of the higher range of distribution than in experimental liver material. The results showed that the surface of the smooth endoplasmic reticulum of human liver is significantly greater than the surface of rough endoplasmic reticulum. Otherwise the morphometric data of the human liver tissue did not differ essentially to the values of the laboratory rat. The variance analytical consideration of the mean evaluated from the data of the 14 liver biopsies indicated that the standard error of nearly all proved parameters was less than 10% of the mean. The results suggest that ultrastructural morphometric evaluation of human liver biopsy samples yield reliable results provided the samples investigated are sufficiently extensive.

Animals↗
PubMed1978

[Ultrastructural-morphometric analysis of polyenylphosphatidylcholine [PPC] treated cholestatic rat liver (author's transl)].

Essential phospholipid PPC was administered to male rats over 24 and 72 hours after operation on bile duct ligation. The subsequent alterations were studied by ultrastructural morphometry and correlated with serum enzyme changes. By the results evidence is accrued that hepatocellular mitochondria are prevented by phospholipid treatment to develop alterations as seen after bile duct ligation alone. This occurred although serum GLDH activity was significantly increased. The smooth endoplasmic reticulum exhibited a normotrophic behavior after PPC treatment of animals in which bile duct ligation was done. The surface of the rough membranes was found increased at hours 24 and 72 after bile duct ligation. The bile canaliculi were markedly dilated. However, this alteration was not accompanied by a marked loss of microvilli. Administration of the phospholipid induced a numerical increase of hepatocellular nuclei in both sham-operated and cholestatic animals independantly from the bile duct ligation. It is suggested by the results that the administration of the phospholipid PPC is of value in influencing the fine structural hepatic alterations as seen in cholestatis.

Alanine Transaminase↗
PubMed1977

[Ultrastructural investigations on the nuclear channel system in the human endometrium (author's transl)].

The Nuclear Channel System (NCS) is a distinct endometrial pattern as observed by transmission electron microscopy. The NCS was identified in the present study in cell nuclei of endometrial glands during mid and late proliferation. These observations do not support the concept that the NCS develops at the ovulation, and is therefore not a typical post ovulatory structure. It is suggested that there are relations between hormonal factors and the development of the NCS which are as yet not clarified.

Cell Nucleus↗
PubMed1977

[Ultrastructural-morphometric investigations on liver biopsies--the influence of oral contraceptives on the human liver (author's transl)].

Liver biopsies from 12 healthy women were investigated morphometrically--according to the methods of Weibel (1969). All women had taken an oral contraceptive agent during 2 til 76 months. The evaluated stereological datas were compared with base-line dates for normal human liver biopsies, which were elaborated in a previous investigation (Roessner et al., 1977). Statistical analysis was performed on an IBM 360/50 computer system, including F- and student's t-test. In the liver biopsy-specimen from the women, which were on oral contraceptives, the volume-density of lysosomes per ml hepatocytes shows a pronounced, significant (p less than 0.001) increase. A moderate increase of cytoplasm is combined with decrease of nuclei-volume. The surface-densities of the rough and smooth endoplasmatic reticulum do not differ significantly from the datas calculated from normal human liver biopsies. All other datas too demonstrate that there are no striking changes in the ultrastructure of human liver, caused by oral contraceptives. Functional alterations however can not be excluded.

Biopsy, Needle↗
PubMed1976

[Transplantable sebaceous adenoma of the mouse with virus particles studied by electron microscopy (author's transl)].

Histology and ultrastructure of a sebaceous adenoma of the mouse -- derived from i.p.-injection of 0.1 ml DNA, isolated from cells of a transplantable mouse-leukemia -- were studied. The original tumour and all transplanted tumours display the same tissular differentiation. In all tumours virus particles were found. Structure and behaviour of the intracytoplasmic A-particles resemble those of the mouse mammary tumour virus while the C-particles found extracellular were identical with the leukemia viruses of the mouse. It might be suspected that mammary tumour virus and leukemia viruses are either non specific or that a new virus is present in the sebaceous adenoma.

Adenoma↗