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Biomedical subjects

H E Stegner

Publications and source records attributed to H E Stegner.

At least 73 records · Page 4Linked to original sources
PubMed1977

The villous stroma of the human placenta. I. The ultrastructure of fixed connective tissue cells.

In human placental villi the connective tissue is constructed by mesenchymal cells, small and large reticulum cells and fibroblasts. During early pregnancy mesenchymal cells dominate; starting with the third month of gestation the reticulum cells are in the majority within the terminal villi, the fibroblasts within the stem villi. Ultrastructurally intermediary types of cells can be differentiated. Together with reticular and collagenous fibres the reticulum cells form the basic architecture of the villous stroma during the first 2/3 of gestation: the "reticular type of stroma". This consists of a network of cells and fibres with fetal vessels fitted in between. The remaining interspaces form a fluid system of compartments in which Hofbauer cells are suspended. They are called stromal channels. During the last trimester these channels and the Hofbauer cells as well are progressively replaced either by voluminous masses of fibres ("fibrous type of stroma", mainly in the stem villi) or by sinusoidal enlargements of fetal capillaries ("sinusoidal type of stroma", mainly in the terminal villi).

Cell Differentiation↗
PubMed1976

The ultrastructure of the interstitial cells in human fetal ovaries.

Steroid-active interstitial cells (stromal lutein cells) in human fetal ovaries of 12, 15 and 22 weeks of gestation were studied by means of electron microscope. The large cells, which are predominantly situated in the vicinity of capillaries, show high structural similarity to Leydig cells (type A) of the fetal testis. Both are characterized by extensively development of smooth endoplasmic reticulum, accumulation of lipids, and numerous mitochondria of the tubular type containing osmiophilic inclusions. Whether the interstitial cell system of the fetal ovary has any specific function in developmental physiology of the genital system cannot be decided on the basis of the present results. Its differentiation may only indicate adequate response of competent mesenchymal cells to gonadotropic stimulation.

Endoplasmic Reticulum↗
PubMed1975

A light and electron microscopic study of endometrial sarcomas of the uterus.

38 endometrial sarcomas were studied light microscopically, 5 of them additionally with the electron microscope. According to their histological appearance these tumours were classified as homologous stromal sarcomas (13 cases), pure heterologous (4) and mixed mesodermal sarcomas (21). The ultrastructure is described with reference to the cytoplasmic differentiation of the tumour cells. A basic immature cell type was present in all endometrial sarcomas irrespective whether they were of pure homologous or of mixed type. In regard to the striking similarity between this cell and cells of the early proliferating endometrium an origin of all endometrial sarcomas from immature stromal cell is suggested. The mixed tumours contain a number of highly differentiated cells like smooth muscle cells, rhabdomyoblasts, fibroblasts etc. As there was a number of cells intermediate in cytoplasmic appearances between immature and differentiated end stages it seems likely that the latter develop from the former. Thus the undifferentiated cell represents the stem cell from which the differentiation processes of all cell lines take their origin. A transition from neoplastic epithelium to neoplastic mesenchyme could not be demonstrated in thed that the mixed epithelial-mesenchymal endometrial tumours originate by a simultaneous malignant transformation of cells with a fixed differentiation potency.

Cell Differentiation↗
PubMed1975

Mixed Müllerian tumors of the uterus. Ultrastructural studies on the differentiation of rhabdomyoblasts.

In the present study the differentiation of rhabdomyoblasts of two carcinosarcomas of the uterus is analysed electronmicroscopically. During the development of rhabdomyoblasts three cell types can be distinguished: 1. the undifferentiated mesenchymal cell with abundant ribosomes but few other cell organelles. Usually these cells are already associated to each other in strands of 2-4 cells. Occasionally cytoplasmic areas with numerous nonspecific filaments can be observed. 2. the light rhabdomyoblast which is characterized by its conspicuous nonspecific cytoplasmic filaments and its reduction in ribosomes. Specific myofilaments can be visualized only occasionally in this cell type. 3. more differentiated rhabdomyoblasts. These cells can be identified clearly by the presence of large numbers of myofibrils and myofibrillar fragments. Higly organized myofibrils as seen in skeletal muscle are seldom found. Transitional forms between these cell types are also observed. The functions of Z-bodies and of the sarcotubular system in the process of myofibrillar differentiation are discussed.

Aged↗
PubMed1975

[Pulsecytophotometric analysis of cervical cells of postmenopausal women (author's transl)].

49 suspensions with cells of the cervix uteri exclusively taken from postmenopausal women were analysed with the pulsecytophotometer. 7 of these cases had an histologically verified invasive cancer of the cervix uteri. There were no false negative results, the percentage of false positive measurements was about 30%. This good result may arise from selecting the cell material analized exclusively from postmenopausal patients and the choice of mathematical model for histogram interpretation, which has been constructed analogously to the cycle of mitosis of cells. Comparing the different methods of preparation of the suspensions the standard procedure (RNase, pepsin, ultrasonic) before staining with ethidium bromide seems to be the best one.

Automation↗
PubMed1975

[Pathological and anatomical aspects of organ-preserving therapy in the early stages of breast cancer].

In the treatment of breast cancer a worldwide trent towards selective and more individualized methods can be observed. Selective treatment depends to a considerable extend on precise morphological diagnosis. Conservative surgery combined with radiotherapy seems to be justified in cases of smallsized carcinomas of stage T0, N0, M0, and T1, N0, M0. There are different opinions on the adequate treatment of non-infiltrating carcinomas (i.e. intraductal comedo carcinoma, non-infiltrating lobular carcinoma). Up till now standard methods are not applicable. The high frequency of multicentric and bilateral development, and the unfavorable mode of segmental canalicular outgrowth are critical factors that must be taken into consideration for individual therapeutic planning.

Breast Neoplasms↗