PubMed Health⌕ Search

Biomedical subjects

H Nemetschek-Gansler

Publications and source records attributed to H Nemetschek-Gansler.

At least 19 recordsLinked to original sources
PubMed1989

Ehlers-Danlos syndrome type IV (EDS IV) as model of a defective biopolymer composite material.

The connective tissue of a lethal EDS IV case was investigated for the reasons of the manifested disturbances of the arterial wall. This functional disorder was attributed to the mechanical decoupling of elastin and collagen, with the premise of a composite material consisting of cellular, fibrillar, lamellar and other matrix components. A conceivable relation between the manifested deficiency of type III collagen and a disturbed anchoring of elastin is shown. These findings are supported by biochemical, morphological, x-ray and mechanical data.

Adult↗
PubMed1986

New aspects of the etiology of tendon rupture. An analysis of time-resolved dynamic-mechanical measurements using synchrotron radiation.

Native collagen fibers were exposed to different dynamic loads to simulate damage to tendons and ligaments relevant clinically and for sports medicine. The results suggest that the rupture of a tendon is caused at the submicroscopic fibrillar level. Not only slow or very fast elongation, but also very fast unloading of stretched fibers seems to be responsible for disseminated damage, which reduces the stability of a fiber. This damage is induced by intrafibrillar sliding processes, which occur only a few seconds before macroscopic slippage takes place. The significance of these events for the beginning and progress of repair in vivo is discussed. The conclusions are supported by simultaneous mechanical and radiological measurements, as well as by light- and electron-microscopic results.

Animals↗
PubMed1986

[Poorly differentiated laryngeal tumors. An electron microscopy analysis].

Poorly differentiated laryngeal carcinomas, which light microscopically are made up of anisomorphic nuclei, undifferentiated cytoplasm and hardly visible cell membranes, show electronmicroscopically a remarquable polymorphism. The tumor cells, which form solid or trabecular groups of different sizes often with poorly defined borderlines to the stroma, are subdivided according to their ultrastructural features in spinosa, secretory and stemcell types. Lymphocytes, plasmacells and reticular cells may show distinct focal proliferation or may be completely absent. In some cases, there was a transition between tumour tissue and metaplastic ciliated and glandular epithelium with concomitant reduction of normal glands. By comparison, besides hyperplastic and metaplastic squamous and ciliated epithelium, normal mucosal biopsies reveal invaginations of pseudostratified ciliated epithelium.

Actin Cytoskeleton↗
PubMed1985

Stress-induced molecular rearrangement in tendon collagen.

Tension-induced molecular rearrangements in wet native fibres of rat-tail tendons and human finger flexor tendons are registered with the help of time-resolved diffraction spectra using synchrotron radiation. The tension-induced increase of the 67 nm D period is combined with changes in the intensities of some orders of the meridional small angle reflection. Both effects are reversible when unloading the fibre, but are preserved when the load is held constant until the fibre tears. The increase in the D period is partly due to a sliding of the triple helices relative to each other and partly due to a stretching of the triple helices themselves. The sliding of the triple helices results in an alteration of the D stagger, leading to a change in the length of the gap and overlap regions, and to a stretching of the cross-linked telopeptides. This interpretation is supported by comparison with the relative intensities derived from a model with varying length of gap and overlap regions, as well as by comparison with model calculations that include the telopeptides.

Adult↗
PubMed1985

[Neuroendocrine larynx cancer of the small cell (oat cell) type. Morphologic and immunohistochemical findings and their significance for therapy].

By combining immunohistochemical, biochemical, and light and electron microscopy techniques, the following original observations concerning the rare and highly malignant small cell ("oat cell") carcinoma of the larynx were made: The typical electron microscopic feature was the presence of neurosecretory granules in some cells. This indicates that this tumour was a carcinoma with endocrinal differentiation. The demonstration of cytokeratins as major cytoskeletal components, as well as the presence of desmosomes, confirmed the epithelial origin of the tumour cells. The detection of neuroendocrinal markers such as calcitonin and neuronspecific enolase (NSE) in some of the tumour cells, as well as the presence of neurosecretory granules allow us to classify this tumour as a neuroendocrinal carcinoma of the small-cell type. This is in accordance with the latest classification of neuroendocrine carcinomas of the lung. The rapid clinical evolution of the disease is typical for patients with anaplastic carcinomas. Laryngectomy followed by adjuvant chemotherapy and radiotherapy is indicated only in cases without metastases. The detection of regional metastases suggests haematogenous spread with distinct metastases, restricting treatment to chemotherapy and radiotherapy.

APUD Cells↗
PubMed1985

[Kaposi sarcoma in acquired immune deficiency syndrome (AIDS). II: Light and electron microscopic and immunohistochemical peculiarities including the cytoskeleton].

AIDS-related lymphoadenopathy is characterised by follicular hyperplasia with irregularities in the dendritic network, a loss of the follicular mantle zone and an enhanced influx of T-suppressor cells into the germinal centres. The histological features of AIDS-associated epidemic Kaposi's sarcoma are spindle-like tumour cells and a source vascularisation, which is of clinical relevance for the biopsy. Since immunohistochemical markers specific for blood vessel endothelium can not be detected within the tumour cells an origin from this cell type gets unlikely. An origin from lymphatic endothelium however can still be discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Transformation of the structure of collagen. A time-resolved analysis of mechanochemical processes using synchrotron radiation.

Mechanochemically induced molecular transformations of collagen fibres were analysed using time-resolved small-angle diffraction spectra and histomechanical measurements. In particular, the influence of aqueous and methanolic perchlorate solutions was examined. According to a transformation continuing from the periphery towards the centre, the macroscopic contraction that is completed less than five minutes after incubation with perchlorate is caused by peripherally transformed fibrils only, whereas the centrally situated fibrils first undergo an accordion-like folding, but after more than 20 minutes are transformed similarly. The triple-helical transformation is preceded by a structure-breaking effect on structural water that can be monitored in time-resolved diffraction spectra. The combined loss of meridional low-angle reflections and cross-striated fibrils in micrographs is irreversible. By dialysis of colloidally dissolved collagen against a solution of ATP, however, segment-long spacing aggregates are obtained. Under isometric conditions, an instantaneous transformation of intermittent regions leads to an increase in the long period of adjacent, still structured regions of the same fibril that is correlated with a delayed increase in tension in the fibre. Increase of tension under isometric conditions as well as the flow-properties of a fibre relaxed in perchlorate are interpreted in terms of the parallel sliding of subunits of varying lengths, which has been demonstrated by diffraction analysis.

Animals↗
PubMed1979

Intimal thickening of human femoral arteries with special regard to elastin, Part 1. Diffuse intimal thickening due to growth and age.

In infants, human femoral arteries display seam-like internal elastic lamina (IEL) covered with endothelium on the luminal side and with smooth muscle cells (SMC) on the medial side. At birth the growth of IEL is finished, correlated with a loss of microfibrils (MF) at the periphery. With the onset of the postnatal vessel growth the joints of IEL seem to be mechanically widened until they have the appearance of gaps with progressing age. After the age of 40 years there are often rod-like crystallites in the IEL, probably composed of cholesterol esters. A small first consecutive lamina (CL) can be seen already in childhood; it enlarges until the 3rd decade of life and is interpreted as a substitute to the "fragmented" IEL. After the 5th decade of life the first CL is arranged within the intima at a certain distance from the IEL and consisting of loosely arranged elastic fibrils. In very old arteries (beyond the 8th decade of life) gaps are rarely seen in the first CL. In individuals over the age of 30 years, the space between IEL and the first CL is occupied by smooth muscle cells (SMC) which are tightly packed. Additional CLs above the first CL can be found in elderly individuals, there CL obviously contribute to the intimal thickening. The ultrastructure of the elastic elements of the vessel wall and their possible function are discussed.

Adolescent↗
PubMed1979

[Etiology and pathogenesis of primary hydrocele in children].

The serous-wall of the typical, non-communicating, idiopathic hydrocele of the child presents with a lympho-static oedema, whose protein-containing fluid is pressed transmesothelially into the lumen. The cause must be seen in the lymph-drainage of the tunica vaginalis testis which follows the obliteration. The above described etiological-pathogenical concept gives the more or less empirical therapeutic-methods a rational basis.

Age Factors↗
PubMed1977

[Disordered fibrillar structure in ruptured tendons (author's transl)].

Areas of disordered fibrillar structure similar to kinking deformities have been observed in specimens from ruptured tendons. It seems possible to compare this phenomenon with experimentally produced deformations. The significance for the pathomechanics of tendon rupture is discussed.

Achilles Tendon↗
PubMed1977

[Kinking deformities in collagen (author's transl)].

The affect of stretch on collagen was investigated. Alterations of mechanical dimensions and thermostability of fibrils were measured and changes in fine structure determined by x-ray diffraction and electronmicroscopy. Collagen underwent changes both in tensile strength and fine structure following stretch beyond the physiological range. The severity of these changes depended both on the degree of stretch and the cross-link density of the collagen Fibrils either became split into bundles consisting of subfibrillar units or showed circumscribed kinking deformities. The mechanism producing kinking was investigated. It is possible that a connection exists between fibrillar kinking and tendon rupture.

Animals↗
PubMed1977

[Banded filamentous associates in the intra- and extracellular space in connection with collagen degradation (author's transl)].

Banded fibrous associates are described in the extracellular space of connective tissue from human endometrium, Ehlers-Danlos syndrome and of tendon rupture. In the cases of morbus Dupuytren these associates are also found as intracellular inclusions. The banded structures are interpreted as states of an enzymatically induced degradation of collagen in correlation with Type-III collagen.

Adult↗
PubMed1976

[The wall of primary hydrocele in childhood. Light and electron microscopic findings (author's transl)].

Hydroceles of infants and children are characterized by edematous wall-thickening, caused by lacking lymph vessels and venous congestion. The morphologic and clinical differences between hydroceles of infants and children favor the following hypothesis: Pathologically increased filtration of fluid from the parietal tunica vaginalis can't be drained into the peritoneal cavity because the processus vaginalis closes too early and gives raise to hydrocele.

Age Factors↗