A bivariate radioimmunoassay for arginine vasopressin and the synthetic antidiuretic agent 1-deamino-8-D-arginine vasopressin (desmopressin)

Pairs of radioimmunoassays, each of which include a two-dimensional matrix of standards, have been previously employed to resolve specificity problems in steroid immunoassay. In this study the bivariate radioimmunoassay principle has been applied to simultaneous measurement of plasma antidiuretic hormone, arginine vasopressin, and the synthetic antidiuretic agent 1-deamino-8-D-arginine vasopressin (desmopressin), by utilizing two arginine vasopressin antisera which show significantly different cross-reactivities with the synthetic analog. Data processing consists of mathematical representation of two curved dose-response surfaces followed by solution of this pair of nonlinear simultaneous equations for the unknown arginine vasopressin and desmopressin concentrations. Details of numerical procedures are given in the Appendix. The assay appears entirely adequate in terms of sensitivity, accuracy, and precision for measurement of these antidiuretic agents in clinical samples. No evidence of significant covariance in estimated concentrations could be detected but precision of estimation is (not unexpectedly) a function of the concentration of both agents. The plasma disappearance half-time of desmopressin (probably the second of a biphasic disappearance) was estimated as 37 min in one normal subject, which is in good agreement with a previously reported value of 30 min.     

The adult fast isozyme of myosin is present in a nerve-muscle tissue culture system

Abstract. Organotypic nerve-muscle cultures were prepared from foetal mouse spinal cord and adult mouse muscle fibres. In this system, the adult fibres degenerate and new myotubes form. The regenerated muscle fibres become innervated, develop cross-striations, and survive for several months. We have investigated the isozymes of myosin present in these muscle fibres using histochemistry and immunocytochemistry with antibodies to rat embryonic, neonatal, and adult fast myosins. We demonstrate that some of the regenerated fibres contain adult fast but not embryonic or neonatal myosin. This is the first demonstration of the production of adult myosin heavy chain in tissue culture. This system therefore offers the possibility for further study of the development of adult myosin isoforms in vitro.     

The “specific” binding of insulin to polyethene and other materials

It is known that insulin is adsorbed onto glass but it has been assumed that it is not adsorbed onto plastic. We find that tritium-labelled insulin is adsorbed onto all materials tried. The adsorption is reduced in the presence of other proteins and can be prevented altogether by coating the vessels with cetyl alcohol.     

cDNA sequences for human von Willebrand factor reveal five types of repeated domains and five possible protein sequence polymorphisms

A human umbilical vein endothelial cell cDNA library in lambda gt11 was screened with two previously described cDNA inserts for human von Willebrand factor. Among 16 positive isolates, two that hybridized with a probe corresponding to the amino terminus of von Willebrand factor were sequenced. Together, these four cDNA inserts span 6.5 kilobases of the von Willebrand factor mRNA sequence, completely specifying the 2050 amino acids of the subunit of mature, secreted von Willebrand factor and 24 residues of a precursor peptide. Approximately 77% of the sequence is contained in five types of repeated domains. Domain A consists of 193-220 amino acids and is present in three tandem copies between residues 497 and 1111. Domain B contains 25-35 amino acids and is present in three copies between residues 1533 and 1636. Domain C consists of 116-119 amino acids and is duplicated between residues 1637 and 1899. In contrast to the essentially contiguous repetition of domains A-C, the two copies of domains D and E are each separated by 804 and 1383 amino acids, respectively. Domain D1 contains 289 amino acids between residues 79 and 367, while domain D2 consists of 270 amino acids between residues 1171 and 1440. Domain E1 consists of 46 amino acids between residues 25 and 70, and domain E2 consists of 46 amino acids between residues 1453 and 1498. The triplicated A domains are notably poor in Cys content, while the remaining domains are Cys-rich. The A domains appear to be homologous to a 225-residue segment of complement factor B.(ABSTRACT TRUNCATED AT 250 WORDS)     

Statistical characterization of nucleic acid sequence functional domains

It has long been recognized that various genome classes were distinguishable on the basis of base composition and nearest neighbor frequencies. In addition Grantham et al. (8) have recently presented evidence that these distinctions are preserved at the level of codon usage. As discussed in this report it is now clear that these and related statistics can uniquely characterize the various functional domains of the genome. In particular peptide coding, intervening segments, structural RNA coding and mitochondrial domains of the vertebrate genome are uniquely characterizable. The statistical measures not only reflect understood functional differences among these domains but suggest others. The ability of these simple statistics of nucleic acid sequences to reflect so much of the encoded complex pattern information and/or effects of selective constraints is somewhat surprising. Here, we investigated the statistical measures most distinctive of the various domains and then linked them to our current understandings in so far as possible.     

“Ischaemic” Colitis in Young Adults

Four cases of transient haemorrhagic colitis seen in young adults resemble 10 others in the literature. The 14 cases are distinguished from the classical transient ischaemic colitis syndrome by their youth, the low incidence of stricture formation, and the prevalence of right-sided lesions.     

Serotonin as a regulator of craniofacial morphogenesis: site specific malformations following exposure to serotonin uptake inhibitors.

During craniofacial development in the mouse embryo (days 9-12 of gestation; plug day = day 1), transient expression of serotonin (5-HT) uptake in epithelial structures of this region correlates with critical morphogenetic events (Lauder et al., '88; Shuey, '91; Shuey et al., '89, '92). The purpose of the present investigation was to assess the possible functional significance of these uptake sites by examination of patterns of dysmorphology following exposure of embryos to selective 5-HT uptake inhibitors. Exposure of mouse embryos in whole embryo culture to sertraline, at a concentration (10 microM) which produced no evidence of general embryotoxicity, caused craniofacial malformations consistent with direct action at 5-HT uptake sites. Two other 5-HT uptake inhibitors, fluoxetine and amitriptyline, produced similar defects. The critical period of sertraline exposure occurred on days 10-11. The observed craniofacial defects were associated with decreased proliferation and extensive cell death in mesenchyme located 5-6 cell layers deep from the overlying epithelium. In contrast, the subepithelial mesenchymal layers showed normal or elevated levels of proliferation. From these results it appears that inhibition of 5-HT uptake into craniofacial epithelia may produce developmental defects by interference with serotonergic regulation of epithelial-mesenchymal interactions important for normal craniofacial morphogenesis.