Culture and differentiation of chondrocytes entrapped in alginate gels.

We studied the response to culture conditions and the differentiative ability in suspension culture in alginate gels of resting chondrocytes from the preosseous cartilage of adult pig scapula. It was found that the maximum rate of chondrocyte duplication is reached at the fourth day in culture whereas the rate of proteoglycan synthesis and alkaline phosphatase expression do not gain a maximum value before the seventh day. During the culture time, the chondrocytes undergo differentiation as it is demonstrated by the alkaline phosphatase specific activity increase and by morphological criteria (hypertrophy, increase of the number of mitochondria per cell, increased endoplasmic reticulum, matrix vesicle production).

Calcium-activated potassium channels in chondrocytes.

The presence of calcium-activated potassium channels in chondrocytes of growing cartilage was tested. Results obtained with fura-2 on cultured resting chondrocytes indicate that the cells respond to an elevation of extracellular calcium concentration ([Ca2+]o) from 0.1 to 2 mM increasing the intracellular concentration of the ion ([Ca2+]i) from 117 to 187 nM.

A potassium channel in cultured chondrocytes.

Chondrocytes, obtained from preosseous cartilage, were studied by patch clamp technique in cell-attached recording configuration, and single potassium channels were characterized at different stages of culture. After 3 days, outward currents were present, with an open probability increasing with depolarization, and the K+ channels showing a mean slope conductance of 82 pS in asymmetric and 168 pS in symmetric potassium solution. Tetraethylammonium (TEA) and quinidine blocked the channels.

[Percutaneous transhepatic bilioplasty: long-term results].

We report the results of a long-term follow-up of 40/101 patients with benign biliary strictures treated with percutaneous balloon dilatation (PBD) at the Radiology Department of the University of Turin, from March 1983 to March 1990. We excluded all the patients who were not followed or treated after June 1988, being their follow-up shorter than 18 months. All patients underwent accurate clinical, biological (AST, ALT, gammaGT, alcaline phosphatase) and US controls.

Modification of plasma membrane of differentiating preosseous chondrocytes: evidence for a degradative process in the mechanism of matrix vesicle formation.

Chondrocytes of the growth plate are differentiating cells. Their evolution leads to matrix vesicle formation and to cartilage mineralization. This is an in vitro study of the plasma membrane of chondrocytes at two differentiation stages.

[Solid-phase conglutinin tests for circulating IgA immunocomplexes].

In some renal, gastroenterological and dermatological diseases the pathogenic role of circulating immune complexes (CIC) of IgA type has been defined. The methods so far proposed to investigate CIC are for the most part able to identify IgGIC, while only few can do the same for IgAIC. The Authors discuss in details the technique and the sensibility and specificity of a new test for IgAIC based on the linkage with the conglutinin in solid phase and propose this test for the clinical study of IgA diseases.