Biomedical subjects

W Jurecka

Publications and source records attributed to W Jurecka.

8 recordsLinked to original sources

PubMed1979

Tactile corpuscle-like structures in a case of plexiform neurofibromatosis.

Tactile corpuscle-like structures were identified in a plexiform neurofibroma, which was localized on the right cranial hemisphere os a 16-year-old boy and had necessitated repeated surgery. These structures were studied by light and electron microscopy. The origin of their component cells is, however, still controversial. We believe to have accumulated sufficient evidence for a Schwann cell origin of these cells.

Adolescent↗

PubMed1979

Effect of different preparation procedures on the ultrastructure of gonococci.

Culture samples of Neisseria gonorrhoeae and Escherichia coli were studied by transmission and electron microscopy to evaluate the effect of different preparation procedures on the pilation of these organisms. Unfixed as well as fixed bacteria showed only few, long, filamentous appendages when investigated in ultrathin sections, negatively stained specimens, or critical-point dried preparations. Snap-frozen specimens of E. coli showed many short and thin pili after being shadowed with carbon and platinum whereas those of N. gonorrhoeae showed only some type-C-like pili. Thus, the number and morphological appearance of pili appear to be greatly influenced by the preparation techniques used for study by electronmicroscopy. Conclusions as to the type and the infectivity of a bacterial strain can, therefore, not be based on purely morphological criteria.

Bacteriological Techniques↗

PubMed1978

Ultrastructural sequence of myelin degradation. II. Wallerian degeneration in the rat femoral nerve.

Myelin degradation in Wallerian degeneration of rat femoral nerves has been studied with the electron microscope. In the initial stages, a decrease of myelin periodicity from 115 A to 88 A was noted, followed by the transformation of the myelin structure into uniformly layered lipid inclusions. 10--14 days after nerve section, most of the inclusions found represented unstructured lipid droplets or crystals. In the later stages of degeneration, numerous pleomorphic lamellar inclusions were found, some of them resembling the structure of pi and micron-granules. Lysosomal enzyme activity was found especially in pleomorphic inclusions during the late stages of myelin degradation. Normal myelin sheaths, as well as unstructured lipid droplets and crystals, were devoid of enzyme activity. The results are compared with alterations found in Wallerian degeneration of the central nervous system.

Animals↗

PubMed1978

Autoradiographic investigation on benzoyl peroxide treated skin.

In vitro autoradiography was used to study the effect of a 5% benzoyl peroxide preparation, or its gel base alone. After three weeks' local application, there was no change in the labelling index of epidermis or follicular infundibulum, while there was a significant reduction in the labelling index of the sebaceous glands. Treatment with the base alone brought about no change.

Acne Vulgaris↗

PubMed1977

[Autoradiographic investigations in actinic (senile) comedones (author's transl].

Skin specimens of patients suffering from actinic comedones, young patients with acne vulgaris, and normal controls of the same age groups respectively were subjected to in vitro autoradiography. From the results it can be concluded, that a rise in the proliferational activity in the follicular infundibulum due to actinic stimuli is responsible for the development and growth of actinic comedones.

Acne Keloid↗

PubMed1977

[Benzoyl peroxide in the treatment of acne vulgaris (author's transl)].

63 patients suffering from predominantly papulo-pustular acne vulgaris were treated with 5-10% benzoyl peroxidegel over a period of 2-4 months. The skin condition showed marked improvement in 80% of the patients. Two patients developed cutaneous allergy. Benzoyl peroxide is the therapy of choice for the inflammatory form of acne vulgaris. Systemic tetracyclines need not be given concomitantly. Autoradiographic studies revealed that benzoyl peroxide also has a truly sebostatic effect.

Acne Vulgaris↗

PubMed1977

Different types of benign nerve sheath tumors. Light microscopy, electron microscopy and autoradiography.

In a light-, electronmicroscopic and autoradiographic study different types of nerve sheath tumors were classified. Their cellular population was quantitatively evaluated in the electron microscope. In the neurinoma the predominant cell was found to be the Schwann cell, but in the different types of neurofibromata a variable content of connective tissue cells was noted. T-HE DIFFUSE NEUROFIBROMATA SHOWED A QUANTITATIVE CELLULAR COMPOSITION SIMILAR TO NORMAL PERIPHERAL NERVES. In the plexiform neurofibroma a large number of fibroblasts were present and in the argyrophilic neurofibroma high content of perineurial cells was found. In autoradiographic sections the tumors showed in general a low proliferation rate (L.i. 1-3.6%). In the argyrophilic neurofibrom a higher labelling index (9.5%) was found.

Adolescent↗

PubMed1977

The epidermal cell proliferation in lichen planus.

The proliferative activity of epidermal structures was determined in 6 patients suffering from lichen planus (i.p.). By using the in vitro 3H-thymidine labelling technique, semithin Epon sections of lesional and perilesional uninvolved skin were compared autoradiographically with normal controls. The following results were obtained. The labelling index of epidermal cells was significantly increased within the i.p. papules. The mean values ranged from 41% in acanthotic i.p. to 23% in atrophic i.p. whereas in adjacent unaffected skin (15% and 11% respectively) as well as in normal controls (6%) a lower 3H-index was observed. As regards damage to basal cells within i.p. lesions, a factor--the relation between the number of basal cells in involved and uninvolved skin in reference to the epidermal length--was calculated in order to correct the autoradiographic results in involved skin. The differences between i.p. papules, adjacent skin and controls remained statistically significant even after correction. The intradermal eccrine ducts revealed a significantly increased labelling index in i.p. lesions as compared with perilesional and normal skin. In this respect no difference could be observed between the acanthotic and the atrophic variant of i.p. These findings indicate that replacement of damaged basal cells in i.p. is achieved by an increase in actively dividing keratinocytes in both epidermis and skin appendages within the lesion.

Cell Count↗