Ossification of the posterior longitudinal ligament (OPLL) of the spine is a subset of "bone-forming" diseases, characterized by ectopic ossification in the spinal ligaments. OPLL is a common disorder among elderly populations in eastern Asia and is the leading cause of spinal myelopathy in Japan. We performed a genomewide linkage study with 142 affected sib pairs, to identify genetic loci related to OPLL. In multipoint linkage analysis using GENEHUNTER-PLUS, evidence of linkage to OPLL was detected on chromosomes 1p, 6p, 11q, 14q, 16q, and 21q. The best evidence of linkage was detected near D21S1903 on chromosome 21q22.3 (maximum Zlr=3.97); therefore, the linkage region was extensively investigated for linkage disequilibrium with single-nucleotide polymorphisms (SNPs) covering 20 Mb. One hundred fifty positional candidate genes lie in the region, and 600 gene-based SNPs were genotyped. There were positive allelic associations with seven genes (P<.01) in 280 patients and 210 controls, and four of the seven genes were clustered within a region of 750 kb, approximately 1.2 Mb telomeric to D21S1903. Extensive linkage disequilibrium and association studies of the four genes indicated that SNPs in the collagen 6A1 gene (COL6A1) were strongly associated with OPLL (P=.000003 for the SNP in intron 32 [-29]). Haplotype analysis with three SNPs in COL6A1 gave a single-point P value of.0000007. Identification of the locus of susceptibility to OPLL by genomewide linkage and linkage disequilibrium studies permits us to investigate the pathogenesis of the disease, which may lead to the development of novel therapeutic tools.

By using a patch clamp technique, we examined the effect of cyclic guanosine monophosphate (cGMP)-dependent protein kinase (G kinase) on Ca(2+)-activated maxi K+ channels in canine coronary artery smooth muscle cells. Maxi K+ channels (274 +/- 4 pS in symmetrical 140 mM KCl at 24-26 degrees C) were activated by cytoplasmic Ca2+ and were completely blocked by 100 nM charybdotoxin (CTX). G kinase (300 U/ml) added to the cytoplasmic face of the membrane patch shifted the voltage dependence of these channels by about 25 mV in the negative direction in the presence of 1 microM Ca2+, 50 microM cGMP and 1 mM magnesium adenosine triphosphate. At -50 mV and 1 microM Ca2+, G kinase treatment increased the mean number of open channels 4.5-fold compared with the control. alpha-Human atrial natriuretic peptide (ANP, 100 nM) reduced the isometric tension of coronary arterial rings elicited by 14 or 24 mM KCl, but failed to relax the artery contracted by 34 mM KCl. Addition of 100 nM CTX augmented tension development elicited by 24 mM KCl and totally prevented ANP from relaxing the arterial rings. These results indicate that G kinase-dependent protein phosphorylation activates maxi K+ channels in canine coronary smooth muscle, and further suggest that the G kinase-induced activation of maxi K+ channels may cause hyperpolarization and relaxation of coronary artery.

A fucose-binding lectin from fruiting bodies of Aleuria aurantia was purified by affinity chromatography by using the H-active glycopeptide of desialyzed porcine submaxillary mucine coupled to Sepharose 4B and eluting with L-fucose. Homogeneity of the active protein was confirmed by polyacrylamide gel electrophoresis, isoelectric focusing, column chromatography using Sephadex G-100, and ultracentrifugal analyses. It has a molecular weight of 72 000 and is proposed to be a dimer of identical subunits, each of which has combining site of uniform affinity. Chemical analyses revealed the absence of the sulfur-containing amino acid and carbohydrate, neutral and amino sugar, in the lectin molecule. It agglutinated human erythrocytes of all ABO and Lewis types, Bombay phenotype, and group O cells treated with alpha (1 leads to 2)-fucosidase. In double-diffusion experiments, the lectin formed a single precipitin line which fused with all of the fucose-containing blood-group substances tested, including the alpha-fucosidase-treated materials. These findings together with the results of hemagglutination and precipitation studies indicate that the lectin combines the terminal fucose in the carbohydrate chain but doses not require a particular linkage to the penultimate sugar moiety.

According to the study results, CTGF/Hcs24 may not only be an important factor in the development of endochondral ossification in OPLL, but may also be responsible for initiating osteogenesis in spinal ligament cells.

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