Ion and water transport characteristics of Nafion ionomer membranes were investigated systematically in the mixed cation form of H+ and various kinds of alkali metal cation systems, which were prepared by equilibrating the membranes in the mixtures of HCl and alkali chloride in aqueous solutions of various mixing ratios. The membrane cationic composition showed that cations of larger atomic number had a higher affinity to sulfonic acid groups but less water content in the membrane than those of smaller atomic numbers. The net ionic conductivity was decreased, in any case, by the presence of alkali metal cations in the membrane. Different kinds of the interaction mode among cations were observed between H/Li or H/Na systems and H/K, H/Rb, or H/Cs systems. The interaction between alkali metal cations appeared to increase as the atomic number of the alkali metal cation increased. The water transference coefficient (electro-osmosis drag coefficient) increased from 2.5 to more than 10 by the presence of alkali metal cations. In the mixed systems, these cations were found to cause less water molecule drag than in the case of individual ions, in the presence of H+ ion. Overall, the transport characteristics of H+ and alkali metal cations influenced each other by way of the water molecules when they coexist in the membrane.

We have previously reported that propolypeptide of von Willebrand factor (pp-vWF) promotes melanoma cell adhesion in a ␤1 integrin-dependent manner. In this report, we identified the ␣ subunit of the cell adhesion receptor for pp-vWF as ␣4. Human leukemia cell lines that express ␣4␤1 integrin (very late antigen-4, VLA-4), but not cell lines which lack VLA-4, attached well to pp-vWF substrate and these adhesions were completely inhibited by anti-␣4 integrin monoclonal antibody HP2/1. Adhesion of mouse melanoma expressing ␣4 integrin was also inhibited by anti-mouse ␣4 mAb PS/2. Furthermore, transfection of human ␣4 cDNA into ␣4 ؊ Chinese hamster ovary cells resulted in an acquisition of adhesive activity to pp-vWF, indicating that pp-vWF is a ligand for VLA-4 integrin. Using a recombinant fragment of pp-vWF, the cell attachment site was shown to be located within amino acid residues 376 -455 of ppvWF. A series of synthetic peptides covering this region were tested for the ability to promote cell attachment and a 15-residue peptide designated T2-15 (DCQDHSF-SIVIETVQ, residues numbered 395-409) promoted VLA-4 dependent cell adhesion. The peptide was also capable of inhibiting cell adhesion to pp-vWF, suggesting that this sequence represents the cell attachment site. By affinity chromatography using peptide T2-15-Sepharose, it was found that ␣4␤1 integrin complex from extracts of surface iodinated B16 cells specifically bound to the peptide. These results strongly suggest that pp-vWF is a novel physiological ligand for VLA-4.Propolypeptide of von Willebrand factor (pp-vWF), 1 which is also called von Willebrand antigen II (1), is an unusually large propolypeptide (ϳ100 kDa) produced only in endothelial cells and megakaryocytes together with blood coagulation protein von Willebrand factor (2). It is processed from a large precursor of vWF (prepro-vWF) during biosynthesis and stored in the granule of both endothelial cells and platelets independent from mature vWF (3, 4). We have been investigating the biological functions of pp-vWF and found that pp-vWF bound to collagen and inhibited collagen-induced platelet aggregation in contrast to the mature vWF (5, 6). Furthermore, we have found that pp-vWF serves as a substrate for transglutaminase and is specifically cross-linked to laminin (7), suggesting a possibility that it acts as transient matrix protein upon secretion from platelets and endothelial cells at the site of vascular injury. In a previous paper (8), we reported that pp-vWF promoted the attachment and spreading of melanoma cells. The receptor responsible for this adhesion was the ␤1 class of integrin but the corresponding ␣ subunit could not be identified.Integrins are heterodimeric transmembrane proteins consisting of ␣ and ␤ subunits and mediate cell adhesion to extracellular matrix proteins as well as cell-cell interactions (9 -12). To date more than 15 ␣ subunits and 8 ␤ subunits have been identified and combination of ␣ and ␤ subunits determines the ligand specificity of individual integrins. Integrin-m...

A clone that contains goat growth hormone (gGH) gene was isolated from a goat genomic library using bovine growth hormone CDNA as a probe. The gGH gene was located on a 5.8-kb EcoRl-Hindlll fragment from the data of Southern hybridization analysis, and the gGH gene and its flanking region were completely sequenced. The nucleotide sequence of the region was highly homologous to those of other animals. The nucleotide sequence homologies of the promoter region of the gGH gene were 98% with the bovine, 90% with the porcine, 74% with the human, and 72% with the rat genes. The consensus sequence for the glucocorticoid receptor binding site was found in the first intron of the gGHgene. Comparison of the 5'-flanking sequences of the gGHgene with those of other animals revealed that there were three homologous tracts amongthose sequences. Wefound conserved sequences in the 3'-flanking region.

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