The role of gamma A/gamma ' fibrinogen in plasma factor XIII activation

Factor XIII zymogen activation is a complex series of events that involve fibrinogen acting in several different roles. This report focuses on the role of fibrinogen as a cofactor in factor XIII activation by thrombin. We demonstrate that fibrinogen has two distinct activities that lead to an increased rate of factor XIII activation. First, the thrombin proteolytic activity is increased by fibrin. The cleavage rates of both a small chromogenic substrate and the factor XIII activation peptide are increased in the presence of either the major fibrin isoform, gammaA/gammaA fibrin, or a minor variant form, gammaA/gamma' fibrin. This enhancement of thrombin activity by fibrin is independent of fibrin polymerization and requires only cleavage of the fibrinopeptides. Subsequently, gammaA/gamma' fibrinogen accelerates plasma factor XIII activation by a non-proteolytic mechanism. This increased rate of activation results in a slightly more rapid cross-linking of fibrin gammaA and gamma' chains and a significantly more rapid cross-linking of fibrin alpha chain multimers. Together, these results show that although both forms of fibrin increase the rate of activation peptide cleavage by thrombin, gammaA/gamma' fibrinogen also increases the rate of factor XIII activation in a non-proteolytic manner. A revised model of factor XIII activation is presented below.     

Linkage analyses of five chromosome 4 markers localizes the facioscapulohumeral muscular dystrophy (FSHD) gene to distal 4q35

The genetic locus for facioscapulohumeral muscular dystrophy (FSHD) has been mapped to chromosome 4. We have examined linkage to five chromosome 4q DNA markers in 22 multigenerational FSHD families. Multipoint linkage analyses of the segregation of four markers in the FSHD families and in 40 multigenerational mapping families from the Centre d'Etude du Polymorphisme Humaine enabled these loci and FSHD to be placed in the following order: cen-D4S171-factor XI-D4S163-D4S139-FSHD-qter. One interval, D4S171-FSHD, showed significant sex-specific differences in recombination. Homogeneity tests supported linkage of FSHD to these 4q DNA markers in all of the families we studied. The position of FSHD is consistent with that generated by other groups as members of an international FSHD consortium.     

A comparative study of PAS-phosphotungstic acid-Diamine Supra Blue FGL and immunological reactions for type I collagen

Summary Immunohistochemical techniques proved valuable in histological studies of various types of collagens. However drawbacks include non-specific reactions of antibodies, masking of antigens, and the high cost of antibodies. This study was undertaken to ascertain the specificity of the PAS-phosphotungstic acid-Diamine Supra Blue FGL (PAS PTA-DSB-FGL) reaction for type I collagen, differentiating it from other collagens. Duplicate series of methaearn-fixed sections of various tissues were treated with the PAS-PTA-DSB FGL reaction and the peroxidase-antiperoxidase (PAP) technique for type I collagen and the staining patterns were compared. Fibers binding the blue dye were found only at sites reacting with antibodies against type I collagen. These observations indicate that the PAS-PTA-DSB FGL procedure is suitable for visualization of type I collagen, e.g. in screening of large series of sections and in the practice of surgical and autopsy pathology.     

An evaluation of 3,4-methylenedioxy phenyl replacements in the aminopiperidine chromone class of MCHr1 antagonists

The optimization of potent MCHr1 antagonist 1 with respect to improving its in vitro profile by replacement of the 3,4-methylenedioxy phenyl (piperonyl) moiety led to the discovery of 19, a compound that showed excellent MCHr1 binding and functional potencies in addition to possessing superior hERG separation, CYP3A4 profile, and receptor cross-reactivity profiles.     

Application of cellulase and hemicellulase to pure xylan, pure cellulose, and switchgrass solids from leading pretreatments

Accellerase 1000 cellulase, Spezyme CP cellulase, β-glucosidase, Multifect xylanase, and beta-xylosidase were evaluated for hydrolysis of pure cellulose, pure xylan, and switchgrass solids from leading pretreatments of dilute sulfuric acid, sulfur dioxide, liquid hot water, lime, soaking in aqueous ammonia, and ammonia fiber expansion. Distinctive sugar release patterns were observed from Avicel, phosphoric acid swollen cellulose (PASC), xylan, and pretreated switchgrass solids, with accumulation of significant amounts of xylooligomers during xylan hydrolysis. The strong inhibition of cellulose hydrolysis by xylooligomers could be partially attributed to the negative impact of xylooligomers on cellulase adsorption. The digestibility of pretreated switchgrass varied with pretreatment but could not be consistently correlated to xylan, lignin, or acetyl removal. Initial hydrolysis rates did correlate well with cellulase adsorption capacities for all pretreatments except lime, but more investigation is needed to relate this behavior to physical and compositional properties of pretreated switchgrass.     

Novel isoxazole carboxamides as growth hormone secretagogue receptor (GHS-R) antagonists

Novel isoxazole carboxamides have been identified as growth hormone secretagogue receptor (GHS-R) antagonists. Substituent modification off the 5-position of the isoxazole ring led to analogues with potent binding affinity and functional antagonism of GHS-R. A potent analogue (32) with high aqueous solubility and good GPCR selectivity was also identified as a potential pharmacological tool for in vivo studies.     

Aminopiperidine indazoles as orally efficacious melanin concentrating hormone receptor-1 antagonists

The synthesis and biological evaluation of novel 3-amino indazole melanin concentrating hormone receptor-1 antagonists are reported, several of which demonstrated functional activity of less than 100nM. Compounds 19 and 28, two of the more potent compounds identified in this study, were characterized by high exposure in the brain and demonstrated robust efficacy when dosed in diet-induced obese mice.