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Biomedical subjects

L Chai

Publications and source records attributed to L Chai.

24 records · Page 2Linked to original sources

[Repair of bone defect of distal end of radius and its functional restoration].

The treatment of the bone defect of the distal part of the radius included repair of the bone defect and restoration of the function of the wrist joint. Since 1979, three operative methods were used to treat 13 cases, and they were grafting of the vascularized fibula by anastomrsis fibular vessels, grafting of upper part of fibular with lateral inferior genicular artery and grafting vascularized scapula flap. Follow-up had been carried out from 1 to 10 years. The result was satisfactory. The discussion included the repair of the defect of the middle or distal part of the radius, the operative methods, main attentions and indications. It was considered that it should be based on the length of bone defect while the operative method was considered.

Adolescent↗

[The anti-tumor efficacy of human recombinant interleukin-2 (rIL-2) in vivo].

Our results suggest that the growth of tumors was significantly suppressed when the high-dose rIL-2 (2 x 10(4)U/day) was injected i.p. in mice bearing subcutaneously (s. c.) transplanted tumors. The inhibition effect on the growth of mouse hepatoma HAC was more potent than that on S180 group. It was found that rIL-2 increased significantly the survival of BALB/C mice bearing HAC tumor (P < 0.001). We have also shown that the adoptive transfer of unfractionated LAK cells plus rIL-2 was more effective than rIL-2 alone. The results also indicated that adherent LAK cells (A-LAK) in combination with rIL-2 had higher antitumor effects as compared to standard LAK cells plus rIL-2.

Animals↗

Distribution of heparan sulfate proteoglycans in embryonic chicken neural retina and isolated inner limiting membrane.

Quantitative distribution of proteoglycans was studied in retinal neural epithelium and its basement membrane (inner limiting membrane). Heparan sulfate proteoglycans (HSPGs) were primarily associated with both inner and outer plexiform (synaptic) layers, and inner limiting membrane (ILM), as determined by autoradiographs of lyase-digested cryosections. Based on distribution of 35S-sulfate-labeled proteoglycans, the isolated ILM contained on average approximately three fourths of its proteoglycans as HSPGs and one fourth as chondroitin sulfate/dermatan sulfate proteoglycans (CS/DSPGs), whereas the remaining retina contained approximately equal amounts of the two proteoglycans (PGs). Immunohistochemical staining indicates that the core proteins of the HSPGs in the ILM are distinct from those of the plexiform layers. The photoreceptor layer, which other studies have shown to contain much of the extracellular CS/DSPGs, was not examined. Enrichment of distinct HSPGs in the ILM and plexiform layers support the conclusion that the HSPGs may be intimately involved in the different developmental events characterizing the two regions: development and extension of ganglion cell axons in the former, synaptogenesis and neuronal function in the latter.

Animals↗

N-band proteins of nucleolar organizers: chromosomal mapping, subnucleolar localization and rDNA binding.

The ribosomal DNA(rDNA)-containing chromatin in eukaryotes forms a unique architecture called the "secondary constriction" or "nucleolus organiser region (NOR)" on mitotic chromosomes. To gain more insight into non-histone chromosomal proteins (NHCP), termed "N-band proteins", that are specifically associated with the NOR in a wide variety of eukaryotes, we attempted to: identify the NHCP responsible for N-band staining; determine their stoichiometry; map them on metaphase chromosomes; determine their subnucleolar localization and examine their possible ability to bind rDNA. Based on several criteria, including chromosomal localization, solubility, association with chromatin, and intra-nuclear localization, two of the nucleolus-rich NHCP, termed component B of mol.wt 55,000 and component C of mol.wt. 41,000, were tentatively identified as N-band proteins. Immunological studies using a polyclonal, monospecific antibody raised against component C show that this protein is in fact associated with the chromosomal telomeres where NORs are located. In nucleoli, N-band proteins appear to be compartmentalized into a structure that probably corresponds to fibrillar components. Both components B and C are among several NHCPs that showed, under in vitro conditions, a strong affinity for rDNA cloned in lambda phage but not for calf thymus genomic DNA or phage vector DNA. The antibody against component C effectively suppressed in vitro transcription by RNA polymerase I in nucleoli and nucleolar chromatin. Component C appears to exist in the nucleus at 3.75-5.13 X 10(3) copies per rDNA unit or 0.09-0.13 copy per nucleotide. These findings support the hypothesis that the NOR is a chromosomal site, architecturally not only unique but also different from other chromatin regions in that constituent DNA, i.e., rDNA, is organized in a specific manner by interacting with specific NHCP, i.e., N-band proteins.

Animals↗