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Biomedical subjects

J D Wade

Publications and source records attributed to J D Wade.

At least 55 records · Page 3Linked to original sources
PubMed1994

Primate relaxin: synthesis of gorilla and rhesus monkey relaxins.

The synthesis of the hormone relaxin from the species Gorilla gorilla (gorilla) and Macaca mulatta (rhesus monkey) has been achieved. Each of the two chains which constitute the peptide structures was assembled separately, the A-chains (24 amino acids) by the Boc-polystyrene solid-phase procedure and the B-chains (29 and 28 amino acids) by the Fmoc-polyamide (gorilla) and the Boc-polystyrene (rhesus monkey) solid-phase methods. After cleavage from the solid supports, the separate chains were purified to a high degree of homogeneity. Oxidative combination of the respective A- and B-chains in solution at high pH afforded the synthetic relaxins in low overall yield. Chemical and physiochemical characterization of the products confirmed both their purity and their conformational similarity to the human hormone. The synthetic gorilla and rhesus monkey relaxins were both found to possess potent chronotropic and inotropic activity in the isolated rat cardiac atrium assay.

Amino Acid Sequence↗
PubMed1993

A peptide corresponding to the N-terminal 13 residues of T4 lysozyme forms an alpha-helix.

Solid-phase methods have been used to synthesize LYS(1-13), a peptide corresponding to the first 13 residues of T4 lysozyme. 2D 1H NMR techniques were used to investigate its solution structure in the presence of SDS micelles. The identification of numerous medium-range NOESY crosspeaks and several slowly exchanging NH protons indicated the presence of an alpha-helical structure. This was confirmed by simulated annealing calculations performed using XPLOR.

Amino Acid Sequence↗
PubMed1991

Use of recombinant DNA derived human relaxin to probe the structure of the native protein.

This report describes the physical, chemical, and biological characterization of recombinant human relaxin (rhRlx) used as a probe to establish the disulfide pairing in native human relaxin. This strategy is necessary since native human relaxin is only available in the nanogram range. The relaxin molecule is composed of two nonidentical peptide chains, an A-chain 24 amino acids in length and a B-chain of 29 amino acids, linked by two disulfide bridges with an additional disulfide linkage in the A-chain. Native relaxin isolated from human corpora lutea was compared to rhRlx by reversed-phase chromatography, partial sequence analysis, mass spectroscopy, and bioassay. The potency of rhRlx was established by its ability to stimulate cAMP from primary human uterine endometrial cells. Native relaxin isolated from human corpora lutea was equipotent to chemically synthesized relaxin, which in turn was equipotent to rhRlx. A tryptic map was developed for rhRlx to confirm the complete amino acid sequence and assignment of the disulfide bonds. The three disulfide bonds (CysA10-CysA15, CysA11-CysB11, and CysA24-CysB23) were assigned by mass spectrometric analysis of the tryptic peptides and by comparison to chemically synthesized peptides disulfide linked in the two most probable configurations. In addition, the observed amino acid composition and sequence of rhRlx was in agreement with that predicted from the cDNA sequence with the exception that the A-chain amino terminal was pyroglutamic acid. The migration of rhRlx upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis was consistent with a monomeric structure, and the identity of the band was demonstrated by immunoblotting.

Amino Acid Sequence↗
PubMed1991

Two-dimensional nuclear magnetic resonance study of brain natriuretic peptide in aqueous solution.

Two dimensional NMR spectra of porcine brain natriuretic peptide have been recorded at 400 MHz. Peak assignments have been made and the combined information from chemical shifts, coupling constants, temperature coefficients, exchange studies and nuclear Overhauser effects has been used to determine the conformation of pBNP in aqueous media. Overall the peptide appears to be conformationally averaged with the possibility of some restricted flexibility in localized regions. The conformation of porcine brain natriuretic peptide in water is compared to previous studies in d6-DMSO and to studies of atrial natriuretic peptide and some closely related analogues in H2O and d6-DMSO.

Amino Acid Sequence↗
PubMed1989

Cardiovascular actions of human endothelin in conscious sheep.

1. Synthetic human endothelin was injected intravenously over the range 1.5-50 micrograms to examine its cardiovascular actions in conscious sheep. 2. Mean arterial pressure increased by 9-21 mmHg within 30-120 s over the range 5-50 micrograms endothelin. The increase in blood pressure was associated with increased calculated total peripheral resistance and a fall in cardiac output and heart rate. Stroke volume was increased. 3. Injection of endothelin into ganglion blocked sheep produced vasoconstriction and an increased blood pressure response associated with an attenuation of the effects on cardiac output, heart rate and stroke volume. 4. This study suggests that endothelin produces potent arterial vasoconstriction and reflex mediated effects on the heart in conscious sheep.

Animals↗
PubMed1989

Class II-restricted T-cell clones to a synthetic peptide of influenza virus hemagglutinin differ in their fine specificities and in the ability to respond to virus.

Fifteen T-cell clones were derived from BALB/c or DBA/2 mice immunized with a synthetic peptide corresponding to the C-terminal 24 residues (residues 305 to 328) of the HA1 chain of H3 subtype influenza virus hemagglutinin. All of the clones proliferated when the peptide was presented in association with I-Ed. By using shorter homologs, it was shown that the T-cell response was focused predominantly on the region at the N-terminal end of the peptide encompassed by residues 306 to 319. Individual clones recognizing this region differed in their absolute requirements for residues at the extremities of the site and also in their patterns of efficiency of recognition of shorter homologs. One particular clone defined another site of T-cell recognition within residues 314 to 328. The response of the clones to peptide analogs identified certain residues within the sites that were critical for recognition, with the substitution Gln-311----Ser having a differential effect on clones responding to the N-terminal site. Only one of the clones responded well to influenza virus itself. This clone also required relatively low concentrations of the parent peptide for optimum stimulation and was suppressed by higher concentrations. The data demonstrate striking heterogeneity in the T-cell response even to a short synthetic peptide, with different T-cell clones recognizing slightly different but overlapping areas of the molecule.

Amino Acid Sequence↗
PubMed1988

Beta-subunit of baboon chorionic gonadotropin. Continuous flow Fmoc-polyamide synthesis of the C-terminal 37-peptide.

The synthesis of a 37-peptide fragment derived from the carboxyl terminal of the beta-subunit of baboon chorionic gonadotropin has been accomplished by the continuous flow Fmoc-polyamide solid phase method. The use of N alpha-fluorenylmethoxy-carbonyl-glutamine with its sidechain protected by the 4,4'-dimethoxybenzhydryl group enabled successful incorporation of this residue onto a hydroxymethyl linkage agent without apparent side reaction.

Animals↗
PubMed1982

Effect of C-terminal chain shortening on the insulin-antagonistic activity of human growth hormone 177--191.

Six synthetic C-terminal shortened fragments of the reduced and S-carbamidomethylated peptide corresponding to residues 177 to 191 of human growth hormone (Cam-hGH 177--191) were assayed for insulin antagonistic activity in vivo. Two of the peptides, Cam-hGH 177--191 and cam-hGH 177--191 were, in nanomolar quantities, both active in that they caused significant hyperglycaemia and insulin resistance in normal rats. The remaining peptides, hGH 177--180, Cam-hGH 177--185, Cam-hGH 177--187 and hGH 177--189 were all inactive even at up to one hundred times the dose employed for the active peptides. The results indicate that an insulin antagonistic core of hGH is contained within amino acid residues 178 to 190 inclusive.

Amino Acid Sequence↗
PubMed1979

Diabetogenic action of human growth hormone. Synthesis and activity of C-terminal fragments.

Three peptides corresponding to the C-terminal region of human growth hormone have been synthesized by the solid-phase method: HGH-(177--191), HGH-(178--191) and HGH-(179--191). The diabetogenic activities of these synthetic peptides are reported. The data indicate that extension of HGH-(179--191) at its NH2-terminus is required for in vivo activity. The reduced and S-carbamidomethylated form of HGH-(177--191) was also active, indicating that the disulphide bond is possibly not a prerequisite for biological activity.

Amino Acid Sequence↗
PubMed1977

The principles and in vivo performance of the Edinburgh pivoted aerofoil-disc prosthetic heart valve.

Prototypes of the Edinburgh prosthetic heart valve, known from previous experiments in vitro to promote exceptionally smooth and undisturbed forward flow, have been shown here in canine experiments to possess hemodynamic characteristics not inferior to those of the Bjork-Shiley valve (a present standard of excellence). In addition, we report a low incidence of valve thrombus deposition among calves in which this prototype valve, fabricated from the conventional materials, Delrin and stainless steel, has been implanted in the tricuspid site for up to 100 days without use of anticoagulants. This suggests that the design of the valve is such as to render it of low thrombogenicity. The new valve is designed for fabrication throughout in vitreous or pyro-coated carbon, materials of very high inherent athrombogenicity. It appears from the results discussed here that the developed form of the prosthesis, composed wholly of these athrombogenic materials, is likely to have both acceptable hemodynamic characteristics and an exceptionally low tendency to form thrombus. The introduction of such valves promises to be very advantageous and the results given here appear to warrant their development as the next stage of this program.

Animals↗