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Biomedical subjects

G Stabellini

Publications and source records attributed to G Stabellini.

At least 91 records · Page 5Linked to original sources
PubMed1985

Avian skin embryonal fibroblasts heterogeneity for lectins surface receptors.

Using several fluorescein-coupled lectins (ConA, WGA and SBA) the distribution of surface ligands in chick embryonic skin fibroblasts was studied at two incubation stages. On the basis of the percentage of lectin marked cells, at least, three fibroblastic populations heterogeneous for surface specific-saccharide binding sites were found. Their relative concentration were changed in the course of incubation, thus indicating developmental changes. We discuss this finding in relation to the regulatory mechanism of the spatial and temporal mesenchymal glycosaminoglycan pattern.

Age Factors↗
PubMed1984

Exogenous glycosaminoglycans (GAG) are able to modulate avian skin differentiation (epithelial keratinization and feather formation).

Several reports have suggested that mesenchymal glycosaminoglycans (GAG) may be involved in the regulatory role of epithelial differentiation. Some researchers have pointed out that exogenous GAG affects extracellular GAG accumulation. We have therefore examined the effect of added GAG on two typical processes of avian skin differentiation: keratinization and feather formation. Glycosaminoglycans, either obtained from fibroblasts cultures (conditioned media) or purified commercially available GAG were administered to 5/6-day chick embryo back skin explants. Control cultures were supported with 199 synthetic medium, chick embryo extract or calf serum. Explants have been examined by histological and histochemical procedures. Skin explants maintained in vitro for 7 days exhibited an epithelial differentiation and a dermal histochemical reactivity which were related to the composition of the culture medium. In conditioned media from dermal fibroblasts, but not from heart or lung fibroblasts, explants always exhibited keratinization. In purified-GAG-containing media, keratinization was observed with condroitinsulphates and not with hyaluronic acid. Keratinization was always related to prevalent accumulation of hyaluronic acid in the underlying mesenchyme whereas feather formation was in relation to deposits of condroitinsulphates in dermis pulp. The above findings demonstrate that exogenous GAG is able to modulate avian skin differentiation and that this regulation is linked to an influence on the mesenchymal GAG pattern.

Animals↗
PubMed1983

[Analysis, by lectin fluorescence, of the cell surface of embryonal fibroblasts cultivated in vitro].

Cultured fibroblast derived from 7 and 14 days chick embryonic skin were tested with three fluorescent lectins (Con A, WGA and SBA). The result obtained shown that the percentage of cells that bind WGA decrease from 7 to 14 days, supporting the presence of an age-dependent heterogeneity at cell surface level. In both cellular population only the 50% of the cell bind to SBA, suggesting a more subtle heterogeneity into the same population.

Animals↗
PubMed1982

[Medium molecular weight uremic toxins and endogenous polyamines. Behavior of polymorphonuclear leukocyte chemotaxis with respect to chromatographic peaks of dialysate and standard polyamines].

The aim of our study is to evaluate the eventual activity of the total dialysate of two uremic nephrectomized patients in recirculating dialysis and the chromatographic peak of the dialysate fractionated by Sephadex column G 15 on PMN chemotaxis. Only the total dialysate and the chromatographic peak B showed inhibition of chemotaxis. On the contrary the commercial polyamines in the same concentration range, and the other chromatographic peaks, containing polyamines too, did not revealed inhibition. Our data show, therefore, that the chemotaxis inhibition could be due to the middle-molecules present in the peak B, rather than the polyamines itself. Polyamines were determined by dansylation method, separated by thin layer chromatography and quantified by spectrofluorimeter. Chemotaxis was evaluated using the modified Boyden chamber.

Chemotaxis, Leukocyte↗
PubMed1980

[Reynolds syndrome associated with Sjögren's syndrome].

Observation of a case of CREST syndrome associated with autoimmune chronic hepatopathy (so-called Reynolds syndrome) and Sjögren's syndrome brings to the fore the importance of symptomatological superimpositions within the autoimmune diseases. A number of diagnostic and pathogenetic aspects of this rare disease association are discussed.

Aged↗
PubMed1979

Estrogen-induced ultrastructural changes in cultured chick embryo hepatocytes.

Administration of estradiol-17-beta induces the synthesis of vitellogenin in primary cultures of chick embryo liver. The ultrastructural changes accompanying steroid induced vitellogenin synthesis were investigated in hepatocytes cultures incubated for 0, 12 and 24 h following hormonal treatment. Both electron microscopy and immuno-chemical techniques were used. The immuno-fluorescence data indicate that the cultures contain a cell population of 90--95% hepatocytes, both in control and estradiol-treated groups. Ultrastructurally, cultured hepatocytes are similar to in vivo ones, except for a reduced accumulation of storage materials, glycogen and lipids. In the estradiol-treated cultures hepatocytes show an accumulation of free ribosomes, enlargement of rough endoplasmic reticulum, and development of the Golgi apparatus.

Animals↗
PubMed1978

Regulation of protein synthesis by estradiol-17beta in cultured hepatocytes.

Estradiol-17beta added to cultured chick embryo hepatocytes induced the appearance in the medium of a phosphoprotein, identified as phosvitin on the basis of: (i) its behaviour on ionic exchange columns; (ii) its SDS-acrylamide gel electrophoretic mobility; (iii) its amino acid composition. The hormone treatment was also followed by a decreased synthesis of other proteins secreted by the hepatocytes.

Animals↗
PubMed1978

Serum-dependent avian skin differentiation in vitro: time sequence of induced events.

Information concerning the developmental mechanisms involved in skin differentiation have been mainly derived from in vitro experiments. We have previously observed that 6-day chick embryonic thigh skin keratinizes in vitro in chicken serum-containing medium, but does not do so in chick embryo extract-containing medium. This system seems adequate in many respects for investigating the mutual regulative relationship between epithelium and mesenchyme (so called epithelio-mesenchymal interactions). We have therefore attempted better to define the time course of differentiative events and their dependence upon the time of serum administration. Skin explants have been sequentially supplemented with differentiation-stimulating or non-stimulating nutrient, removed at different intervals and examined by histological and histochemical procedures. Different epithelial and mesenchymal behaviour results according to serum supplementation time. Serum administered in the first 48 h of in vitro maintenance is unable to stimulate either the subsequent epidermal keratinization or the correlated changes in dermal histochemical pattern. On the other hand, serum-containing medium induces keratinization and changes in dermal intercellular composition (glycoproteins accumulate to a greater extent than glycosoaminoglycans, as does hyaluronic acid relative to chondroitin sulphuric acids), if added for only the second two days. In the last 48 h, serum may promote epidermal keratinization provided that in vitro incubation has been prolonged. Administration of actinomycin D with serum in the second 48 h prevents epidermal keratinization and modifies dermal histochemical reactivity, but is ineffective if added in the last 48 h. The above findings demonstrate that serum factor(s) stimulating epidermal differentiation act(s) on skin explants in the central incubation period and that correlatively mesenchyme acquires a characteristic histochemical pattern, supporting the possibility that the effect of serum may be mediated by changes in the composition of dermal ground substance.

Animals↗
PubMed1976

Studies on the mechanism of in vitro estradiol-17 beta induced synthesis of phosvitin in chick embryo liver cells.

The effect of estradiol-17-beta treatment on phosvitin synthesis by cultured chick embryo liver cells has been studied. Phosvitin synthesis occurs approximately 15 hr of hormone treatment; the synthesis being blocked by actinomycin D treatment suggests that RNA synthesis is required. The life time of the newly synthesized RNA is at least 24 hr. The significance of these findings with respect to the mechanisms involved in hormone-mediated protein synthesis is discussed.

Animals↗