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Biomedical subjects

V Mandys

Publications and source records attributed to V Mandys.

17 recordsLinked to original sources
PubMed1991

A modification of tooth germ cultivation in vitro and in ovo.

Mandibular molar anlages excised from 17-day mouse foetuses were cultured in vitro or in ovo (on the chorioallantoic membrane). In both cases, the explants were underlain either with a Millipore filter or with a piece of fibrin foam. Tooth germs were harvested after 7 days of cultivation and processed histologically. Spatial arrangement was highly preserved in the tooth germs cultured in vitro on fibrin foam. In vitro cultures on Millipore filters revealed significant flattening of tooth germs, caused especially by the collapse of enamel organ and the pulp. The cytodifferentiation of tooth germs cultured in vitro on both substrates (Millipore filter, fibrin foam) was characterized by the presence of odontoblasts, polarizing ameloblasts and predentine. The cytodifferentiation of tooth germs cultured in ovo on Millipore filters placed on chorioallantoic membrane was characterized by the presence of odontoblasts, ameloblasts, predentine, dentine and enamel. However, the flattening of these explants was identical with the changes of the explants cultured on Millipore filters in vitro. In ovo cultivation on the fibrin foam failed to bring satisfactory results.

Ameloblasts↗
PubMed1991

Cultivation of rat fetal spinal cord slices in a semi-solid medium: a new approach to studying axonal outgrowth and regeneration.

A soft agar culture system was used for the cultivation of spinal cord slices with the purpose of improving the evaluation of the dynamics of axonal outgrowth and development. Slices of the spinal cord of 15-day-old fetal Wistar rats were cultured in a 0.5% agar culture medium. The sprouting and outgrowth of axons from the slices was observed at 6-24-h intervals. The morphology and growth rates of axons could be easily investigated by light microscopy. Quantification of growth parameters of individual neurites is made easy because no cells migrate out of the slices, so that the outgrowth is not masked by migrating neurons, fibroblasts, glial cells etc. The axons had well-developed growth cones, comparable to those observed in liquid medium; the daily growth rate was on average 318 microns during the 6 days of observation, with a maximum of 1050 microns per day. Back-labelling with a fluorescent dye (DiI) indicated that the longest neurites originated from motoneurons. Our experiments show that axons can develop and grow in a soft agar medium without the need for adding any growth promoting factor or substrate molecule.

Agar↗
PubMed1990

Morphological changes in the human thyroid gland cultivated in continual flow system.

In the present pilot study, the human thyroid gland tissue was cultivated under continuous culture conditions in the culture chambers of the ACUSYST-S system to determine morphological changes as well as the secretion of thyreoglobulin (Tgl) and thyroid hormones. After 24 hours of cultivation the follicular structure of the tissue was preserved in peripheral parts only, and there were regressive changes in the epithelium center. After 72 hours the regressive changes appeared in isolated follicles only; the size of the follicles increased, the height of the follicular epithelium decreased and there were macrophages present with phagocytized cell debris. After 144 hours disintegration of epithelia took place in the centre, while at the periphery the original follicles survived and very tiny new follicles formed, consisting of only 6 to 8 cells each and surrounding in section the homogeneous colloid. The parenchyma picture suggests a possibility of functional regeneration as an expression of adaptation to the conditions newly arisen during cultivation in a culture chamber. There was no significant influencing of the thyroid hormone secretion during cultivation. On the other hand, the Tgl secretion decreased throughout cultivation.

Culture Media↗
PubMed1989

[Functional ultrastructure of the thyroid gland in rats].

Thyroid gland from normal and hormonally influenced rats (by application of exogenous Triiodothyronine and Thyroid stimulating Hormone), were investigated by means of classical electron microscopy. Dense granules, micropinocytotic and macropinocytotic structures were observed similarly as was already published. Triiodothyronine and Thyroglobulin were localized by affinity cytochemistry on ultrathin cryosections from normal rat thyroid gland. These method showed, that particular endocytotic and exocytotic structures can't be distinguish only by simple morphology and that functional status of these structures can be evaluated only by detection of contained molecules. Triioodthyronine was observed by affinity cytochemistry in multivesicular bodies and in lateral intercellular spaces. That findings indicate, that Triiodothyronine is internalized (transcytosed) by Receptor-mediated endocytosis. Affinity cytochemistry is useful for study of triiodothyronine and thyroglobulin movement in the thyroid gland.

Animals↗
PubMed1988

Irritation effects of residual products derived from p(HEMA) gels. II. Compounds extracted from hydrogels.

Samples of poly(2-hydroxyethyl methacrylate) p(HEMA) hydrogels were prepared using three different polymerization initiators. The gels were washed in water under standard conditions. The extracts were then examined for intradermal irritation in rats using a radioactive indicator (113mIn). The irritation effects were dependent on the concentrations of the irritating substances and also on the gel type. Solid discs made of the gels, washed to varying degrees of purity, were also implanted into rats. Tissue irritation, as well as some other biological responses, were followed in situ using the radioindicator and common histological techniques. The irritation effects were very mild (even with the unextracted gel material). A possible explanation for the events taking place at the site of implantation is presented.

Animals↗
PubMed1988

A new cell line, GS, derived from a human renal cell carcinoma.

A new cell line, GS, of human renal cell carcinoma was established and characterized. It was derived from a metastasis of a human renal cell carcinoma, which appeared 6 years after nephrectomy. The GS cells exhibit basic characteristics of renal cell carcinoma: epithelial cell character, PAS and glycogen positivity, typical ultrastructural features. The cells have a pseudotriploid stemline with a modal number of 75 chromosomes and two marker chromosomes. GS cells formed neither colonies in soft agar nor transplantable tumours in nude mice but produced a factor(s) stimulating growth and colony forming activity of indicator cells.

Aged↗
PubMed1987

[Menkes syndrome].

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Brain Diseases, Metabolic↗
PubMed1987

Heterogeneity of lymphocytic colonies in agar culture.

Cytochemical methods and electron microscopy were employed to examine lymphocytic colonies grown in semisolid media for the presence of a heterogeneous cell population consisting mainly of T lymphoblasts with an admixture of B-series elements and monocytoid-macrophagic cells.

Agar↗
PubMed1986

Biostability and morphology of tissue reaction of some synthetic polymers.

Synthetic polymers as tissue substitute are more and more widely used in medicine today. Therefore it is necessary to continue to complete our knowledge on the subject of the mutual interaction of the organism and tissue substitutes of synthetic polymers. The influence of the organism on the degradation processe of some synthetic textile fibres made of polyester was studied polypropylene and polyamide, which are either suggested or already used in the production of vascular protheses and other tissue substitutes. The morphological picture of tissue reaction to implanted synthetic fibres, the mechanical properties of the fibres and changes in their surface structure after 4-360 days after implantation were also studied.

Animals↗
PubMed1986

[Epithelial tumors of the large intestine in short-term tissue culture (relation to biological behavior)].

Short term tissue cultures on space substrate were made from 13 samples of normal colonic mucosa and non-tumours colonic lesions as well as from 28 samples of epithelial colonic tumours. The growth and morphological features of cultivated tumours were mostly connected with their original histological structure and biological behaviour. Epithelial structures from adenoma and carcinoma survived longer than those from non-tumorous lesions. Epithelial cells from villous adenomas and from familiar polypous colonic adenomas showed increased proliferation on space substrate similar to the growth of carcinoma cells.

Adenoma↗
PubMed1986

Relation between high-frequency electrical impedance and malignity of two L cell sublines.

Two L cell sublines (L-As and LC3), differing in the ability to induce sarcomas in irradiated C3H mice, were grown on special gold electrodes interrupted in the middle by a 50 micron wide slot. Electrical impedance of the two sublines was compared at 100 kHz in a special measuring device connected with an apparatus used for impedance measurement in clinics. Significantly lower values of impedance characterized the LC3 cells, which induced more sarcomas in susceptibility hosts than the L-As cells. This result agrees with the findings in human tumors compared with corresponding normal tissue or benign growth, and stresses the importance of the cell population as such in impedance measurements.

Animals↗
PubMed1985

Myotube-like structures in cultures of rat liver cells.

Branching and budding myotube-like structures developed in primary cultures of rat liver cells and in the JH1 cell line derived from them. Elongated uninuclear cells aligned in chains and fused into multinuclear tubes of varying length and thickness. The tubes contained thick and thin filaments running in all directions. The filaments were occasionally linked with M lines and formed incomplete hexagonal patterns resembling those of skeletal muscle myofilaments, but a regular arrangement of the filaments and organelles was lacking. Cross-striation and contractions were never observed. Both uninuclear cells and multinuclear tubes contained numerous lysosomes, myelin figures and lamellated bodies as well as electronlucent or content-filled vacuoles and cisternae of variable size, sometimes reminding the sarcoplasmic reticulum in early stages of its development. Endocytotic caveolae and vesicles were present in all elements. These features together with interdigitated cell processes and specialized cell contacts suggested a possible relationship of the cells to the reticuloendothelial system.

Actin Cytoskeleton↗
PubMed1985

[Homocystinuria].

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Child, Preschool↗
PubMed1978

[An unusual case of polydactylia].

A woman of 85 had a symetrical malformation of the hands manifested as a combination of syndactyly of the soft parts of the 3rd and 4th fingers and an incomplete bifurcation of the bones of the 4th finger.

Female↗