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Biomedical subjects

G Williams

Publications and source records attributed to G Williams.

At least 649 records · Page 36Linked to original sources
PubMed1985

Treatment with danazol and plasma glucagon concentration.

The association between treatment with danazol and hyperglucagonaemia was studied. Plasma glucagon concentrations were measured during an oral glucose tolerance test in seven women taking danazol and six healthy controls not taking danazol. Results showed that treatment with danazol is associated with severe hyperglucagonaemia, and in three patients glucagon concentrations reached the range suggestive of glucagonoma. It is important to recognise that this increasingly used drug may cause severe hyperglucagonaemia to prevent patients treated with danazol undergoing unnecessary investigations to localise glucagonoma.

Adult↗
PubMed1985

Solution structure of mitochondrial cytochrome c. I. 1H nuclear magnetic resonance of ferricytochrome c.

The 1H nuclear magnetic resonance spectra of tuna and horse ferricytochromes c have been investigated and the resonances of all amino acid methyl groups have been assigned to specific absorption lines. The assignment procedure involves principally the comparison of one-dimensional nuclear magnetic resonance spectra from a range of homologous ferricytochromes c and does not require a prior knowledge of the secondary or tertiary protein structure. Of the 49 methyl groups of tuna cytochrome c, the assignment of 33 is made without reference to the X-ray crystal structure. The method should therefore be applicable to other proteins of similar size where X-ray structures are unavailable. The assignments will be used to investigate the structure of cytochrome c in solution.

Amino Acid Sequence↗
PubMed1985

Solution structure of mitochondrial cytochrome c. II. 1H nuclear magnetic resonance of ferrocytochrome c.

The 1H nuclear magnetic resonance spectrum of tuna ferrocytochrome c has been studied and the resonances of all 49 amino acid methyl groups have been assigned to specific absorption lines. In comparison with resonance assignments in the ferricytochrome c spectrum, the secondary shifts of resonances of ferrocytochrome c are smaller and the identification of characteristic spin-systems from comparison of spectra from homologous proteins more difficult. For this reason, two-dimensional nuclear magnetic resonance exchange correlated spectroscopy has been used to correlate the assigned resonances of tuna ferricytochrome c with previously unassigned resonances of tuna ferrocytochrome c.

Amino Acid Sequence↗
PubMed1985

Comparison of the solution and crystal structures of mitochondrial cytochrome c. Analysis of paramagnetic shifts in the nuclear magnetic resonance spectrum of ferricytochrome c.

The two accompanying papers describe the assignment of methyl-containing spin-systems in the 1H nuclear magnetic resonance spectra of tuna ferricytochrome c and tuna ferrocytochrome c. At present, 104 resonances from 208 C-H protons are assigned in both oxidation states. In this paper, the difference in chemical shift of a resonance between the two oxidation states is used together with a dipolar model of the unpaired electron spin of ferricytochrome c to compare the structure of cytochrome c in solution with three high-resolution structures of cytochrome c obtained by X-ray diffraction in single crystals. The overall protein fold and the positions of most of the haem-packing residues are shown to be invariant between the crystal and solution. However, three regions of the protein, at the C terminus, around the haem propionic acid groups and at the haem crevice near thioether-2, are found to undergo conformational changes on the removal of crystal packing constraints.

Amino Acid Sequence↗
PubMed1985

Histochemical changes after ureterosigmoidostomies and colonic diversion.

Forty patients with colonic urinary diversions were studied for morphological and histochemical changes in the colon using haematoxylin and eosin, and high iron diamine alcian blue stains. Eighty-nine per cent of ureterosigmoidostomies biopsied at the ureteric orifice and 44% biopsied distal to the orifice showed "transitional" changes thought to represent a pre-malignant state. Thirty-eight per cent of patients who had had ureterosigmoidostomies in the past and 100% of the colon conduits also demonstrated this change. The earliest "transitional" change occurred 1 year after the diversion. This and the low incidence of morphological changes in this group of patients suggest that the finding of "transitional" mucosa is of no value in the follow-up of patients with colonic urinary diversions.

Adolescent↗
PubMed1985

Pre-excitation due to accessory sinoventricular connexions associated with coronary sinus aneurysms. A report of two cases.

Ventricular pre-excitation occurred in two cases in which the accessory pathways between the atria and the ventricles were histologically identified as being associated with aneurysmal malformations of the coronary sinus. In one case the connexions were in the posterior wall of the coronary sinus aneurysm and were not related to the atrioventricular annulus; in the other, a connexion was situated in the anterior wall of the aneurysm in close apposition to the annulus and superficially resembled a Kent fibre. These connexions were considered to be of sinus venosus origin and to represent a modification of the muscular sheath that normally surrounds the coronary sinus but does not continue along the coronary veins. One of the posterior wall connecting bundles was composed of abnormally large Purkinje-like fibres; this may have played some role in the manifestation of the pre-excitation by reducing any mismatch impedance.

Adolescent↗
PubMed1985

Congenital diaphragmatic hernia in half sibs.

Half brothers from the same mother had congenital left sided posterolateral diaphragmatic hernias repaired in the neonatal period. The inheritance of diaphragmatic hernia should probably be based on the multifactorial hypothesis.

Female↗