Nerve compression syndromes of the extremities

An analogue of human melanin-concentrating hormone (MCH) suitable for radioiodination was designed in which Tyr13 and Val19 of the natural peptide were replaced by phenylalanyl and tyrosyl residues: [Phe13, Tyr19]-MCH. The peptide was synthesized by the continuous-flow solid-phase methodology using Fmoc-strategy and polyhipe PA 500 and PEG-PS resins. The linear MCH peptides with either acetamidomethyl-protected or free cysteinyl residues were purified to homogeneity and cyclized by iodine oxidation, yielding the final product with the correct molecular weight of 2434.61. Radioiodination of the C-terminal tyrosine was carried out enzymatically using solid-phase bound glucose oxidase/lactoperoxidase, followed by purification on a reversed-phase mini-column and by high-pressure liquid chromatography. The resulting [125I]-[Phe13, Tyr19]-MCH tracer was the first radiolabelled MCH peptide suitable for radioreceptor assay: saturation binding analysis using mouse G4F-7 melanoma cells demonstrated the presence of 1090 MCH receptors per cell. The dissociation constant (KD) was 1.18 x 10(-10) M, indicating high-affinity MCH receptors on these cells. MCH receptors were also found in other cell lines such as mouse B16-F1 and G4F and human RE melanoma cells as well as in PC12 and COS-7 cells. Competition binding analyses with a number of other peptides such as alpha-MSH, neuropeptide Y, substance P and pituitary adenylate cyclase activating peptide, demonstrated that the binding to the MCH receptor is specific. Atrial natriuretic factor was found to be a weak competitor of MCH, indicating topological similarities between MCH and ANF when interacting with MCH receptors.     

Assessing the risk of gestational diabetes in twin gestation

This study examines the hypothesis that twin gestation is a risk factor for gestational diabetes. In a retrospective analysis, the incidence of gestational diabetes in twin and singleton pregnancies was determined in groups matched for maternal age, weight, and parity. One-hour oral glucose challenge tests (50 g) were used to screen 9185 pregnant women. Gestational diabetes was diagnosed when abnormal screens (> or = 130 mg/dL) were followed by two or more abnormal values on a 3-hour (100 g) glucose tolerance test using National Diabetes Data Group (NDDG) criteria. A twin gestation was identified in 1.5% (138/9185) of the pregnancies. Gestational diabetes was diagnosed in 5.8% (8/138) and 5.4% (439/9047) of the twin and singleton pregnancies, respectively. The incidence of gestational diabetes is similar for singleton and twin gestations.     

Regulation of the TRP Ca2+ channel by INAD in Drosophila photoreceptors

Drosophila vision involves a G protein-coupled phospholipase C-mediated signaling pathway that leads to membrane depolarization through activation of Na+ and Ca2+ channels. InaD mutant flies have a M442K point mutation and display a slow recovery of the Ca2+ dependent current. We report that anti-INAD antibodies coimmunoprecipitate TRP, identified by its electrophoretic mobility, cross reactivity with anti-TRP antibody, and absence in a null allele trp mutant. This interaction is abolished by the InaD point mutation in vitro and in vivo. Interaction was localized to the 19 amino acid C-terminus of TRP by overlay assays, and to the PDZ domain of INAD, encompassing the point mutation. Given the impaired electrophysiology of the InaD mutant, this novel interaction suggests that INAD functions as a regulatory subunit of the TRP Ca2+ channel.     

Effect of acute alterations in afterload on left ventricular function in patients with combined coronary artery and peripheral vascular disease

The GTP analog guanylylmethylene diphosphonate (GppCH2p) strongly inhibited polyuridylic acid-directed polypeptide synthesis in a cell-free translation system prepared from Agrobacterium tumefaciens. Fusidic acid increased even further the inhibitory action. The pre-translocational ribosomal complexes formed with the GppCH2p and the elongation factor G protected the ribosome against the depurinating action of crotin 2 assayed as the acid-dependent release of the RNA fragment whose terminal sequence is 5'-GAGGACCGGGAUGGAC-3'. The results allowed to conclude that the interaction of both crotin 2 and the elongation factor G with the A. tumefaciens ribosomes in the pre-translocational state must take place at overlapping, either sterically or allosterically, ribosomal sites which are equally accessible to the RIP.