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Biomedical subjects

A Lametschwandtner

Publications and source records attributed to A Lametschwandtner.

At least 73 records · Page 4Linked to original sources
PubMed1982

[Angioarchitecture of the retroauricular skin in humans. Scanning electron microscope studies of corrosion casts].

The angioarchitecture of the skin of the retroauricular area of a 25-year-old and a 55-year-old man was studied by scanning electron microscopy of vascular corrosion casts. Special attention was paid to the arrangement of the capillary bed of the stratum papillare corii. There is an average of 40 capillary loops per mm2. The diameters of the ascending loops of the capillaries range between 12.3 and 15.3 microns, of the descending ones between 19.0 and 22.9 microns, the length of the capillary loops is between 326 and 407 microns. The range of confidence is 95 percent. Three different patterns of arteriovenous anastomoses were found within the papillary and partly in the subpapillary capillary bed. The results showed no difference between the vascular beds of the two men. The scanning electron microscopy of vascular corrosion casts and its significance in the normal and pathological vascular bed is discussed.

Adult↗
PubMed1981

[The vascular pattern in solid and cystic basal cell tumors (author's transl)].

In addition to other criteria, the growth pattern, macroscopic form, and histologic examination of a tumor are heavily influenced by the tumor's blood supply. Rapid size increases of basal cell carcinomas in certain of our patients has led us to examine the capillary network of such tumors. Known histologic patterns were summarized, and the tumor vascular patterns evaluated by scanning electron microscopy of corrosion preparations. For this, an artery leading to the tumor was cannulated, and a thin synthetic resin ("Mercox" liquid) injected. After precipitation, the preparation was macerated in aqueous sodium hydroxide. The vascular changes encountered could thus be illustrated in three-dimensional form. In addition to changes specific in the tumors (i.e., caliber fluctuations, cyst formation at vessel ends, and degeneration forms), peculiar formations could be found in various sites, suggesting that capillary neogenesis was taking place within the tumors.

Capillaries↗
PubMed1980

[Experimental heterograft tracheal transplants in animals. III. Light microscopic, scanning and electron microscopic findings (author's transl)].

In seven three-month old piglets, tracheal defects were created experimentally and Cialit-fixed human tracheal transplants were grafted at the site of the defect. The implants did well in five of the animals, and no signs of respiratory insufficiency (such as stridor, dyspnea or cyanosis) were found. 230-273 days after the transplantation, the animals were sacrificed and the tracheas removed. The transplants were then examined macroscopically and by light, scanning and transmission electron microscopy. Two questions arose: 1) What was the fate of the epithelium of the tracheal graft? It was then found that the host tracheal epithelium surrounding the graft resurfaces the graft. However, a series of morphological changes occur and are described in detail. 2) What happens to the grafted tracheal cartilage? It was found that the cartilage was replaced by thick connective tissue and scar. From the results of these studies, two conclusions could be drawn. 1) The repair of tracheal defects by means of Cialit-fixed human tracheal grafts is limited in those cases in which the newly formed connective tissue is not able to stabilize the tracheal tube. 2) The size of the heterologous tracheal transplant is limited to 6-7 cm2 in animal experiments.

Animals↗
PubMed1979

Endothelial lesions after temporary clipping. A comparative study.

The effect of temporary clipping on the arterial endothelium of rats was examined with scanning electron microscopy. The opening pressure of four Heifetz clips was modified by changing the springs. Four different clip forces (20, 35, 45, and 65 gm), four periods of clipping (10, 30, 60, and 180 minutes), and three vessel diameters (smaller than 1 mm, 1.1 to 1.3 mm, and 1.4 to 2 mm) were compared. Different grades of endothelial damage were observed. On gross examination the damage involved a detachment of endothelium and the adherence of platelets to the subendothelial tissue. The duration of clipping seemed to be of more importance than the clip force, whereas the vessel diameter had no recognizable influence.

Animals↗
PubMed1979

[Experimental heterograft tracheal transplants in animals. II (author's transl)].

In sequence with an earlier publication on the results of heterograft tracheal transplants in animals, changes in the Formol-Cialit preserved heterogenous tracheal grafts were studied by light microscopy, and by scanning and transmission electron microscopy. Two main queries arise. Where does the graft respiratory epithelium come from, and what happens to the grafted tracheal cartilage? We found that in the epithelium of graft the number of ciliated cells decreased and that there was ultrastructure evidence of cilial destruction, the goblet cells increased in number, there was a loss of strict polarity of the respiratory epithelium, subepithelial accumulations of cells of probable epithelial origin appeared, and there was a subepithelial accumulation of lymphocytes just beneath the basal lamina. Resorption and transformation of the grafted tracheal cartilage into connective tissue was also observed. Hence, the following conclusions may be made. (1) Small tracheal defects can be corrected by Formol-Cialit preserved heterologous grafts. (2) The mucosa of the host trachea produces a functioning respiratory epithelium in the graft. (3) Tracheal grafts should not exceed 2 x 3 cm in size otherwise a new stenosis from resorption and transformation of grafted cartilage into connective tissue will occur.

Animals↗
PubMed1979

[The pathogenesis of tracheal stenosis following thyroidectomy (author's transl)].

The frequency of trachealmalacia or stenoses following operations for struma or recurrent struma initiated our study of the pathogenesis of such changes. This study revealed that mechanical factors, such as compression of the trachea and the like, had been reported in the literature as the causative factors. The present paper investigates to what extent disturbances in the blood supply of the trachea, particularly after ligature of the inferior thyroid artery during thyroidectomy, influence changes in the tracheal mucosa, the connective tissue, and the adjacent cartilage. In twelve experiments on domestic pigs, the blood supply of the cervical trachea was interrupted. After varying periods of survival time, the animals were sacrificed and the tracheas histologically examined. In all cases, ischemic changes in the tracheal mucosa and cartilage could be found in addition to inflammatory reactions with scar formation. It seems justified to conclude that both mechanical factors and disturbances in local blood supply can cause tracheal tissue changes after thyroidectomy. The inferior thyroid artery and its branches also seem to play a central role in the success or failure of tracheal reconstructions following end-to-end anastomoses after stenosis resections. As a consequence, this paper also deals comprehensively with the detailed anatomy of this vessel.

Adult↗
PubMed1979

[Results of heterologous tracheal transplants in animal experiments (author's transl)].

In the present study, 7 x 15 mm Cialit-preserved human tracheal segments were grafted to the tracheas of five 3-month old piglets. 72-120 days later, the animals were sacrificed and the grafts with proximal and distal control areas were removed. Tissues were then examined macroscopically and by light and scanning electron microscopy. We found that: (1) all grafts had taken well; (2) no animal suffered from clinical signs of respiratory obstruction or inflammation; (3) although luminal diameters of the tracheas increased from 8 mm to 22 mm, the size of the grafts remained unchanged but the resulting tracheal stenosis did not cause respiratory obstruction; (4) the graftet areas showed re-epithelialization. The nature of the re-epithelialization as well as the fate of the submucosa and tracheal cartilage will be reported in a subsequent publication.

Adult↗
PubMed1978

[Light and scanning electron microscopical studies of the soft palate and the tongue in Bombina variegata L (author's transl)].

The soft palate and the tongue of adult Bombina variegata L. were studied by means of light and scanning electron microscopy. In the palate numerous taste-disks were found prominent by their polygonal surface structures. These are caused by longer microvilli at the margins of the different cells of the taste-disk or by deepened margins of the polygonal cells. The surfaces of the cells are slightly convex and are covered by numerous microvilli. In the tongue primarily fungiform papillae were observed (with the exception of the margins were taste-disks similar to those found in the palate were present). Their taste-disks also present polygonal structures, their epithelial cells are characterized by microridges while those of the epithelial folds surrounding the fungiform papillae own microvilli. As special formations within the taste-disks small knob-like protrusions between polygonal cells were found.

Animals↗
PubMed1977

A new cell type in the taste buds of anurans. A scanning and transmission electron microscopic study.

A hitherto undescribed cell type within the fungiform papillae of the tongue of the toad, Bufo bufo (L.) and the taste-disks of the soft palate of Bombina variegata L. was identified by means of scanning and transmission electron microscopy. This cell type is characterized by an apical protrusion carrying numerous microvilli. Bundles of filaments are present in the cytoplasm of the protrusion. Vesicles with electron lucent content and microtubules are present thoughout the cytoplasm of the cell.

Animals↗
PubMed1977

The vascularization of the neural stalk and the pars nervosa of the hypophysis in the toad, Bufo bufo (L.) (amphibia, anura). A comparative light microscopical and scanning electron microscopical study.

The angioarchitecture of the neural stalk and the encephaloposthypophysial portal system of the hypophysis of the toad, Bufo bufo (L.), was studied using three different methods. The neural stalk is mainly supplied by branches of the arteria infundibularis superficialis which form a widemeshed vascular network. Dorsally this network continues into the plexus of the pars nervosa. The vascularization of the pars nervosa is made up of the encephalo-posthypophysial portal system. This portal system consists of a hypothalamic branch (=portion), a mesencephalic and a mesencephalicbulbar branch (=portion). The hypothalamic branch was found to drain the pars ventralis of the tuber cinereum as well as more dorsal regions of the diencephalon. The mesencephalic-bulbar trunk enters the hypothalamic branch. The resulting common stem of the encephalo-posthypophysial portal vein the curves around the retroinfundibular communicating artery, crosses its ventral side and runs caudally. The secondary capillary plexus of the pars nervosa is characterized by well defined capillary plexus of the pars nervosa is characterized by well defined capillary networks which are located at the periphery of the parenchyma of the pars nervosa, thus forming a rostral, dorsal and ventro-caudal net. The central region of the parenchyma of the pars nervosa is supplied only by main branches of the encephalo-postpophysial portal vein. The venous drainage of the pars nervosa is via the vena hypophysea transversa.

Animals↗
PubMed1977

Vascularization of the pars intermedia of the hypophysis in the toad, , Bufo bufo (L.) (Amphibia, Anura). A comparative light microscopical and scanning electron microscopical study. II.

The vascularization of the pars intermedia of the hypophysis of the toad, Bufo bufo (L.) was studied by injection of a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further methyl-methacrylate corrosion casts of brains were made and the hypophysial region of the corrosion casts was examined with the scanning electron microscope. The results showed that the vascularization of the pars intermedia of the toad hypophysis consists of a single-layered vascular network, which is located on the ventral surface of the pars intermedia. The network is formed by capillaries, which primarily run caudally in a fan-like manner and which show only a few cross-connections. In the rostral region of the pars intermedia this network lies rather superficially, while in the caudal region it slightly penetrates the parenchyma. The vascular network originates from vessels of the neural stalk and from wide capillaries of the rostro-ventral region of the neurointermediate junction. The venous drainage of the pars intermedia is exerted by veins, which leave the caudal region and drain into the veins leaving the venous pole of the pars distalis. The flat, wide meshed vascular net on the ventral side of the pars intermedia, demonstrated in this study, fits into the concept that the pars intermedia of the anuran hypophysis is under the control of nerve fibers coming from the hypothalamus.

Animals↗