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Biomedical subjects

G Mall

Publications and source records attributed to G Mall.

177 records · Page 10Linked to original sources
PubMed1978

An effective morphometric method for electron microscopic studies on papillary muscles.

Morphometry was performed on the left ventricular posterior papillary muscles of seven Wistar rats. The volume densities of myocardial cells, interstitial space, myocardial nuclei, sarcoplasm, mitochondria, myofibrils, ground substance and T tubules, and the surface densities of myocardial cells, mitochondrial membranes and T tubules, were calculated. Though only 1 ultrathin section per animal was evaluated the low standard errors of the means indicate that the method described here will be adequate in most experimental studies. Due to the anisotropy of the surfaces within myocardial cells, the papillary muscles were cut at an angle of 32.4 degrees to their longitudinal axis. This angle is derived from an equation published by Whitehouse (1974). The procedure to correct the loss of cristal membrane images from oblique sectioning is discussed.

Animals↗
PubMed1975

[Bilateral renal hypoplasia with oligomeganephronie. A morphometric, light- and electronmicroscopic study (author's transl)].

Kidney biopsy specimens of three patients with a special form of hypoplasia, the oligomeganephronic hypoplasia (Oligomeganephronie) were studied with light- and electron-microscopy as well as morphometric methods. The morphometric measurements demonstrated that there were no quantitative differences of the glomerular components between normal and oligomeganephronic glomeruli of patients of the same age. All of the structures measured--glomerular capillary surface, glomerular volume, volume of the glomerular capillary lumina and volume of Bowman's capsular space--were increased about 5.4 times. The volume of the proximal and distal tubules per mum tubular length in oligomeganephronic patients was disproportionally increased. The total number of glomeruli was more diminuished than mentionned in the literature until this time. The secondary glomerular sclerosis, initially focal, was progressive and supposed to be caused by "chronic overwork".

Adolescent↗
PubMedDate not supplied

[Experimental visualization of the ventricular conduction system of the heart intra vitam (author's transl)].

The in-vivo tolerability of an in vitro in cow, calf and sheep hearts developed method for radiologic visualization of the left ventricular conduction system is tested in four animal experiments. The clinical in-vivo tolerability could be demonstrated on principle; however, it is to accent that hypertonic X-ray contrast dyes may be the cause of morphological changes in the micro- and ultrastructures of the specialised musculature of unknown dignity.

Animals↗
PubMedDate not supplied

Capillary neoformation in the rat heart--stereological studies on papillary muscles in hypertrophy and physiologic growth.

Stereological investigations on myocardial capillaries provided evidence that the common estimator of capillarity, the capillary density (i.e., number of capillary profiles per unit transverse sectional area), underestimates the true capillary supply since the capillary axes are not oriented perfectly in parallel to the myofiber axes. Recently, we studied the "true" capillarity, i.e., the length density of capillaries (LV = capillary length per capillary volume), in some experimental models of cardiac hypertrophy which have been published elsewhere. It has been shown that LV decreases in renovascular hypertension, but is maintained in physical exercise and after chronic thyroxin application. However, the growth pattern of capillaries in hypertrophic hearts has not yet been analyzed. In the present paper it is demonstrated that important information on the capillary network can be derived from the two-dimensional capillary-to-fiber ratios (2D CFR: capillary profiles per myofiber profiles in transverse sections) and from the three-dimensional capillary-to-fiber ratios (3D CFR: capillary length per unit myofiber length). Increase in both suggests neoformation of additional capillary branches in parallel connection. Retrospective analysis of the quantitative data indicates that in hypertrophy induced by physical exercise or by chronic thyroxin application capillary neoformation in parallel connection counterbalances increase of oxygen diffusion distance due to myofiber enlargement. In renovascular hypertension, capillary neoformation in parallel connection does not occur. Studies on normal growth indicated both a slight decrease of LV of capillaries, as well as a continuous neoformation of additional capillary branches.

Animals↗
PubMedDate not supplied

Morphometric analysis of the rabbit myocardium after chronic ethanol feeding - early capillary changes.

Male rabbits were fed with ethanol for 3 weeks. 10 ml of a 20% ethanol solution were applied daily with a stomach tube. The macroscopic, histologic and ultrastructural investigation of the hearts did not reveal and structural alterations. Morphometrically, the endothelial cells of the capillaries were changed, whereas the muscle cells did not show any abnormalities. The quantitative data indicate that the numerical density of endothelial cells is increased, whereas the volume density is not changed. This type of quantitative reaction pattern may be characterized as "proliferation" of endothelial cells. The proliferation is possibly related to ethanol-induced metabolic changes similar to chronic hypoxia. On the other hand, there is some evidence that the alteration is part of a general activation of mesenchymal cells in various organs after ethanol ingestion. The alteration is probably an early stage of the proliferation of capillaries.

Animals↗
PubMedDate not supplied

Endometriosis: a dysfunction and disease of the archimetra.

Endometriosis is considered primarily a disease of the endometrial-subendometrial unit or archimetra. The clinical picture of endometriosis characterises this disease as a hyperactivation of genuine archimetrial functions such as proliferation, inflammatory defence and peristalsis. While the aetiology of the disease remains to be elucidated, a key event appears to consist in the local production of extraovarian oestrogen by a pathological expression of the P450 aromatase. The starting event may consist in a hyperactivity of the endometrial inflammatory defence, a hyperactivity of the endometrial oxytocin/oxytocin receptor system or in the pathological expression of the P450 aromatase system itself. Regardless of which of these levels the starting event is localized in, they influence each other on both the level of the archimetra and the endometriotic lesions. Locally elevated oestrogen levels inevitably up-regulate the endometrial oxytocin mRNA and increased levels of oxytocin result in uterine hyperperistalsis, increased transtubal seeding of endometrial tissue fragments and finally subfertility and infertility by impairment of the uterine mechanism of rapid and sustained sperm transport. Locally increased levels of oestrogen lead, on both the level of the endometrial-subendometrial unit and the endometriotic lesion, to processes of hyperproliferation. These processes result, on the level of the uterus, in an infiltrative growth of elements of the archimetra into the neometra and, on the level of the endometriotic lesion, in infiltrative endometriosis. There is circumstantial evidence that trauma might be an important initial event that induces the specific biochemical and cellular responses of the archimetra. This model is able to explain both the pleiomorphic appearance of endometriosis and the, up until now, enigmatic infertility associated with mild and moderate endometriosis.

Aromatase↗
PubMedDate not supplied

[Collagen and fibrin as biologic binders for granular hydroxylapatite].

In an animal experiment the use of the biologic binders collagen and fibrin for the temporary stabilization of the shape of granular hydroxyl apatite grafts has been tested. A simple way of producing a hydroxyl apatite fibrin paste involves the use of a thrombin solution diluted to 1 i.u./ml. The fibrin-bound polygonal granules (Interpore 200) studied did not grow denser during the interposition of fibrous tissue, while the molded specimens of collagen-bound granules (Alveoform) underwent condensation involving a 30% decrease in intergranular distance.

Adhesives↗
PubMedDate not supplied

[Pathogenesis, diagnosis and therapy of heart disease caused by enteroviruses (molecular biological study)].

Molecular hybridization studies have demonstrated that human enteroviruses, including group B coxsackieviruses (CVB), are detectable in myocardial tissue of patients with acute and chronic myocarditis. As well, such infections are observed in some patients with end-stage dilated cardiomyopathy indicating the possibility of persistent heart muscle infection. Enterovirus persistence in the human heart is supported by the discovery in various murine models of chronic myocarditis, demonstrating that coxsackievirus B3 (CVB3), typically a cytolytic virus, is capable of evading immunological surveillance in a host-dependent manner. Currently attention is focused on the analysis of molecular mechanisms of virus persistence, the characterization of viral and host factors and their impact in determining the natural course of myocardial enterovirus infections. The evidence for a causal linkage of enterovirus infection with heart muscle diseases has emerged therapeutic implications. From the view of a virologist, immunosuppressive treatment of patients revealing enterovirus infection in the myocardium with steroids is clearly contraindicated. The evaluation of potent antiviral agents, such as interferons, in established in vitro and in vivo model systems of enterovirus infection is expected to contribute significantly to new therapeutic strategies in human enteroviral heart disease.

Animals↗