[en] Chondroitin sulfate represents approximately 15% of the ³⁵SO₄-labeled glycosaminoglycans carried by the proteoglycans of the cell surface and of the basolateral secretions of normal mouse mammary epithelial cells in culture. Evidence is provided that these chondroitin sulfate-carrying proteoglycans are hybrid proteoglycans, carrying both chondroitin sulfate and heparan sulfate chains. Complete N-desulfation but limited O-desulfation, by treatment with dimethyl sulfoxide, of the proteoglycans decreased the anionic charge of the chondroitin sulfate-carrying proteoglycans to a greater extent than it decreased the charge of their constituent chondroitin sulfate chains. Partial depolymerization of the heparan sulfate residues of the proteoglycans with nitrous acid or with heparin lyase also reduced the effective molecular radius of the chondroitin sulfate-carrying proteoglycans. The effect of heparin lyase on the chondroitin sulfate-carrying proteoglycans was prevented by treating the proteoglycan fractions with dimethyl sulfoxide, while the effect of nitrous acid on the dimethyl sulfoxide-treated proteoglycans was prevented by acetylation. This occurrence of heparan sulfate-chondroitin sulfate hybrid proteoglycans suggests that the substitution of core proteins by heparan sulfate or chondroitin sulfate chains may not solely be determined by the specific routing of these proteins through distinct chondroitin sulfate and heparan sulfate synthesizing mechanisms. Moreover, regional and temporal changes in pericellular glycosaminoglycan compositions might be due to variable postsynthetic modification of a single gene product

[en] Confluent cultured human lung fibroblasts were labeled with 35SO4(2-). After 48 h of labeling, the pericellular matrix was prepared by Triton X-100 and deoxycholate extraction of the monolayers. Heparan sulfate proteoglycan (HSPG) accounted for nearly 80% of the total matrix [35S]proteoglycans. After solubilization in 6 M guanidinium HCl and cesium chloride density gradient centrifugation, the majority (78%) of these [35S] HSPG equilibrated at an average buoyant density of 1.35 g/ml. This major HSPG fraction was purified by ion-exchange chromatography on Mono Q and by gel filtration on Sepharose CL-4B, and further characterized by gel electrophoresis and immunoblotting. Intact [35S]HSPG eluted with Kav 0.1 from Sepharose CL-4B, whereas the protein-free [35S]heparan sulfate chains, obtained by alkaline borohydride treatment of the proteoglycan fractions, eluted with Kav 0.45 (Mr approximately 72,000). When analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography, core (protein) preparations, obtained by heparitinase digestion of 125I-labeled HSPG fractions, yielded one major labeled band with apparent molecular mass of approximately 300 kDa. Reduction with beta-mercaptoethanol slightly increased the apparent Mr of the labeled band, suggesting a single polypeptide structure and the presence of intrachain disulfide bonds. Immunoadsorption experiments and immunostaining of electrophoretically separated heparitinase-digested core proteins with monoclonal antibodies raised against matrix and cell surface-associated HSPG suggested that the major matrix-associated HSPG of cultured human lung fibroblasts is distinct from the HSPG that are anchored in the membranes of these cells. Binding studies suggested that this matrix HSPG interacts with several matrix components, both through its glycosaminoglycan chains and through its heparitinase-resistant core. (Abstract Truncated)

[en] In 19 cases of secondary hematologic disorders in patients previously treated for Hodgkin's disease, chromosome aberrations were analyzed in relation to the type of previous chemo- and/or radiotherapy, age of the patients, histopathologic features of the Hodgkin's disease at diagnosis, time interval between the treatment and the occurrence of the secondary disorder, and survival. The karyotype was of significant prognostic value when three cytogenetic groups were considered: patients with normal karyotypes; patients with aberrations of chromosome 7 as the sole anomaly; and patients with complex rearrangements and translocations. The last group showed the lowest rate of survival. Bone marrow transplantation was successful in two patients with a normal karyotype

[en] Cultured amniotic-fluid cells from a fetus at risk for homozygous familial hypercholesterolaemia (F.H.) almost completely lacked cell-surface receptors for plasma low-density lipoprotein (L.D.L.), as evidenced by direct measurement of binding, uptake, and degradation of ¹²⁵ I-L.D.L. Functional consequences of L.D.L. binding to the receptor - i.e., suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase and stimulation of cholesterol esterification - were proportionately reduced when compared with results in cultured amniotic cells from two control fetuses. On the basis of these findings, homozygous F.H. was diagnosed and the pregnancy was terminated at the 20th week. The diagnosis of homozygous F.H. was confirmed by a serum-cholesterol of the aborted fetus of 279 mg/dl, a value 9 times the mean of four control fetuses of similar gestational age. More than 80% of the serum-cholesterol of the affected fetus was contained within L.D.L. Prenatal diagnosis of homozygous F.H. now seems practical; moreover, the finding of a raised serum-L.D.L. in the affected fetus indicates that the L.D.L. receptor is normally functional as early as the 20th week of fetal life. (author)

[en] Collagen metabolism was compared in cultures of mouse mammary epithelial cells maintained on plastic or fibrillar type I collagen gel substrata. The accumulation of dialysable and non-dialysable [³H]hydroxyproline and the identification of the collagens produced suggest no difference between substrata in the allover rates of collagen synthesis and degradation. The proportion of the [³H]collagen which accumulates in the monolayers of cultures on collagen, however, markedly exceeds that of cultures on plastic. Cultures on collagen deposit a sheet-like layer of extracellular matrix materials on the surface of the collagen fibers. Transformed cells on collagen produce and accumulate more [³H]collage, yet are less effective in basement membrane formation than normal cells, indicting that the accumulation of collagen alone and the effect of interstitial collagen thereupon do not suffice. Thus, exogenous fibrillar collagen appears to enhance, but is not sufficient for proper assembly of collagenous basement membrane components near the basal epithelial cell surface

[en] This paper reports a recent study on applying a knowledge-based system approach as a new attempt to solve the problem of chromosome classification. A theoretical framework of an expert image analysis system is proposed, based on such a study. In this scheme, chromosome classification can be carried out under a hypothesize-and-verify paradigm, by integrating a rule-based component, in which the expertise of chromosome karyotyping is formulated with an existing image analysis system which uses conventional pattern recognition techniques. Results from the existing system can be used to bring in hypotheses, and with the rule-based verification and modification procedures, improvement of the classification performance can be excepted