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Biomedical subjects

D G Williams

Publications and source records attributed to D G Williams.

At least 199 records · Page 11Linked to original sources
PubMed1976

Disease activity in the nephritis of systemic lupus erythematosus in relation to serum complement concentrations. DNA-binding capacity and precipitating anti-DNA antibody.

Serum C4 and C3 concentration and binding of double-stranded-DNA (ds-DNA) were measured in sera from ninety-nine patients with systemic lupus erythematosus and clinical evidence of nephritis. C3 and C4 concentrations correlated poorly with ds-DNA binding. In sera from fifty-three patients, precipitating antibody was sought using the counterimmunoelectrophoretic technique. Precipitating antibody was detected on at least one occasion in 44% of the patients, and these sera with precipitating antibody showed higher binding of ds-DNA and lower C4 concentrations than those without precipitating antibody. In thirty-two patients, serial assessments of the activity of the renal disease were made using decline or improvement in glomerular filtration rate, degree of proteinuria, oedema and hypertension as indices of "activity". All patients were receiving immunosuppressive drugs. Active nephritis was rarely found in patients showing, at that time, a normal serum C4 or normal ds-DNA binding; but a raised ds-DNA binding or lowered serum C4 were found in both active and inactive nephritis. There was no correlation of activity with serum concentrations of C3, or the presence or absence of precipitating antibody. We conclude that measurements of serum-complement concentrations and binding of ds-DNA are of most use in the diagnosis of systemic lupus erythematosus, and that in patients with nephritis and taking immunosuppressive drugs, these tests are of limited use in guiding treatment.

Antibodies, Antinuclear↗
PubMed1975

The effect of excess dietary iodine on pregnant mares and foals.

On a thoroughbred stud four foals were born with greatly enlarged thyroids and leg weakness. Two foals died within 18 hours of birth, the others subsequently recovered. An enlarged thyroid was also evident in one of the resident mares. The thyroids from the dead foals were hyperplastic. Feed analyses showed that the mares had an iodine intake of about 83 mg daily, 8-8 ppm of the dietary dry matter, due almost entirely to the high iodine content of a proprietary compound horse nut which had been fed at the daily rate of 12 lb per head. It was concluded from the histology of the thyroids, the high intake of iodine, the lack of response to treatment with potassium iodide and the elevated levels of serum protein bound iodine that the condition of the foals on the stud was caused by an excess of iodine fed to the mares during pregnancy.

Animal Feed↗
PubMed1975

Mechanisms of activation of the properdin system. Studies on properdin electrophoretic mobility in agarose activation of the alternative pathway.

The electrophoretic mobility of properdin in agarose with and without EDTA examined in sera from normal subjects and from patients with mesangiocapillary glomerulonephritis, systemic lupus erythematosus, rapidly progressive glomerulonephritis, mesangial IgG-IgA disease, minimal change glomerulonephritis and partial lipodystrophy. In 'EDTA agarose", the properdin arc of normal serum was always cathodal (gamma), whereas in non-EDTA agarose it was always (beta), indicating that agarose activated properdin with its consequent conversion from a cathodal to an anodal form. Using this change in the mobility of properdin to investigate activation of the properdin system, it was found that the lower the C3 concentration of diseased sera, the less able were they to support properdin conversion by non-EDTA agarose. This relationship we interpret as a manifestation of the requirement of an intact C3b feedback pathway for properdin activation. This view was supported experimentally by (i) decreasing ability of non-EDTA agarose to shift properdin mobility in normal serum as it was progressively depleted of components of the alternative pathway by cobra venom factor, C3 nehritic factor or Mg2+, and (ii) the inability of non-EDTA agarose to shift properdin in sera depleted of C3 or factor B, and in serum deficient in C3. The report of other workers that activated properdin causes generation of C3b, coupled with our finding that properdin activation depends on the C3b feedback, indicates that a system exists in which activation of the C3b feedback cycle allows activation of properdin, allowing in turn further amplification of the C3b feedback. That the anodal form of properdin may be a property of activated properdin was shown by our observations that properdin eluted from zymosan was anodal and activated, and that the properdin in the supernatant normal serum incubated with inulin was anodal.

Complement C3↗
PubMed1974

Metabolic studies of the third component of complement and the glycine-rich beta glycoprotein in patients with hypocomplementemia.

Metabolic studies using radioiodine-labeled third component of complement (C3) and the glycine-rich beta glycoprotein (GBG), a major component of the C3b-feedback pathway, were undertaken in normal subjects, in 22 patients with evidence of complement activation, and in 11 patients with various renal diseases without evidence of complement activation. In seven normal subjects GBG was found to be a rapidly metabolized protein with catabolic rates ranging from 1.7% to 2.2% of the plasma pool/h, synthesis rates from 0.14 to 0.21 mg/kg per h. and extravascular/intravascular distribution ratios from 0.81 to 1.31. In patients with reduced plasma C3, both increased C3 fractional catabolic rates and reduced C3 synthesis rates were observed, and in some patients there was evidence of increased extravascular distribution of the protein. GBG catabolism was usually increased when there was evidence of C3 activation, presumably reflecting activation of the C3b-feedback; but GBG turnover was normal or only slightly accelerated in some patients with accelerated C3 catabolism and profound hypocomplementemia, suggesting that reduced C3 synthesis had limited activation of the C3b-feedback.

Complement Inactivator Proteins↗
PubMed1973

Glomerular deposition of properdin in Henoch-Schönlein syndrome and idiopathic focal nephritis.

Biopsy of renal tissue from four patients with idiopathic focal nephritis and three patients with Henoch-Schönlein syndrome showed that C3 and properdin were deposited with IgA in the glomerular mesangium, C1q could not be detected. These observations suggest that glomerular injury in disorders characterized by mesangial deposits of IgA and C3 is mediated via the properdin system.

Biopsy↗