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Biomedical subjects

A R Clarkson

Publications and source records attributed to A R Clarkson.

At least 91 records · Page 5Linked to original sources
PubMed1977

Salivary antipyrine kinetics in hepatic and renal disease and in patients on anticonvulsant therapy.

The effects in man of liver disease, renal failure and hepatic microsomal enzyme induction on the elimination kinetics of antipyrine in saliva have been examined. Antipyrine (10 mg/kg) was given orally and assayed in saliva by gas-liquid chromatography. The mean antipyrine half-life from saliva in nine epileptic subjects receiving long term anticonvulsant drug therapy (6 hr +/- 0-9 SEM) was significantly shorter than in twenty normal healthy volunteers (10-7 +/- 0-6). Therapy included phenytoin and phenobarbitone, two drugs known to induce hepatic microsomal enzymes. Five subjects with chronic renal failure exhibited no significant difference in salivary anti-pyrine half-life (11-7 +/- 1-9) compared to the control group, whereas six subjects with chronic liver disease and impaired hepatic function had significantly increased half-life values (42-4 +/- 10). The results suggest that differences in the activity of hepatic microsomal enzymes are reflected by changes in salivary antipyrine elimination kinetics. Chronic renal failure appeared to have no effect on the function of these enzymes.

Adult↗
PubMed1977

IgA nephropathy: a syndrome of uniform morphology, diverse clinical features and uncertain prognosis.

Isolated glomerulonephritis with mesangial IgA deposits was the most common single finding encountered in a large biopsy series in an Australian community and was found in 50 patients, 18% of those presenting for the investigation of primary glomerular disease. A uniform histopathological picture of mesangial enlargement, with or without focal and segmental features was present. A tendency to progression was suggested by the frequent presence of glomerulosclerosis, interstitial scarring and vascular hyalinization. Because of the uniform histological immunofluorescence and ultrastructural appearances, the term IgA nephropathy has been used for this condition. The clinical picture, however, was heterogenous. Presenting symptoms included macroscopic hematuria (34%), proteinuria (32%) acute nephritis (10%), nephrotic syndrome (6%), malignant hypertension (8%), acute renal failure (6%) and chronic renal failure (4%). There was a striking correlation of increased blood pressure and decreased renal function with increasing age. While the period of follow-up was too short to assess individual patient data, a gradual and progressive decrease in renal function over several decades is suspected in patients with this condition.

Adolescent↗
PubMed1976

Renal and cardiac complications of drug abuse.

The case is presented of a young man who, after prolonged intravenous narcotic administration, developed subacute bacterial endocarditis involving the aortic valve, and rapidly progressive glomerulonephritis. After treatment of and recovery from renal failure, persistent proteinuria was shown to be caused by focal glomerulosclerosis. The association of these lesions with "mainlining" is reviewed.

Adult↗
PubMed1976

Coagulation and renal disease.

The role of coagulation in relation to the aetiology, pathogenesis and progression of renal diseases is discussed. The intimate interdependence between the coagulation process and platelet function, fibrinolysis, complement activation and kinin release is emphasized; these processes are usually involved in most types of immunological inflammation. Coagulation abnormalities occurring in distinct renal diseases are reviewed and the benefits derived from therapy aimed at correcting these abnormalities are compared with the known natural histories of these diseases.

Animals↗
PubMed1976

Phenformin and lactic acidosis.

Thirty-eight patients who presented with diabetes and a changed state of consciousness satisfied the criteria for lactic acidosis. Sixteen patients were non-ketotic, and 15 of these were receiving phenformin on admission. In all but one of these 15 patients, however, additional renal or cardiovascular abnormalities, or both, could be identified, which supported a multifactorial aetiology for lactic acidosis. Advanced age and cardiovascular and renal disease are absolute contraindications to the use of phenformin in diabetics.

Adolescent↗
PubMed1976

Clinical and haemodynamic effects of minoxidil in refractory hypertension.

Thirteen patients whose hypertension had been resistant to conventional drug therapy, had minoxidil added to their regimen in doses from 5 to 60 mg/day. All responded with satisfactory reductions of blood pressure to mean values of 149/90mm Hg (supine) and 143/89mm Hg (standing). A significant portion of their previous antihypertensive therapy was either greatly decreased or withdrawn completely. Although fluid retention occurred in most patients as the dose of minoxidil was increased, this could be successfully checked by the use of diuretics. It was considered that in addition to beta-adrenoreceptor blocking drugs to control the reflexly induced cardiac stimulation, sufficiently aggressive diuretic therapy is mandatory to ensure the successful use of this drug. Haemodynamic evaluations in seven patients clearly showed that lowering of blood pressure was the result of decreases in peripheral vascular resistance as significant increases in the cardiac index occurred in all patients.

Adult↗
PubMed1976

Morphological and immunological evidence of coagulopathy in renal complications of pregnancy.

Renal biopsies in 14 patients with P.E.T. or eclampsia showed constant I.F. reactions for IgM and fibrin, with frequent reactions for C1q and C3. The glomeruli showed reversible mesangial proliferation and swelling, with characterictic E.M. deposits, and segmental lesions were present in seven patients. Similar I.F. reactions occurred in three other patients with clinical diagnoses of P.E.T. whose biopsies demonstrated coexistent glomerular disease. Serum complement studies showed a significant rise in C3 in the third trimester of normal pregnancies and a further significant elevation in C1q and C3 in the third trimester of a series of unselected P.E.T. patients. In contrast, four patients from the biopsy series with eclampsia or severe P.E.T. showed profound depression of serum C3 and C4, at the time of maximum clinical severity, which was shown to return to normal in two patients. The I.F. findings confirm those of Petrucco et al (6), and, with the other data, suggest that immune-complex deposition and activation of the classical complement pathway could interrect with intravascular coagulation to produce the glomerular lesions of P.E.T. and eclampsia.

Adolescent↗
PubMed1974

Urinary excretion of C3 antigen in glomerulonephritis.

C3 and fibrin degradation products (F.D.P.) have been measured in early morning urine samples from 38 normal people and 123 patients with glomerulonephritis. Normal urine contained less than 0.3 mug of either antigen per ml. C3 and F.D.P. were both detected in the urine of many patients with glomerulonephritis. Levels above 1 mug/ml were exceptional in patients with "minimal change," and the highest excretion of both antigens occurred in mesangiocapillary glomerulonephritis, membranous nephropathy, and focal glomerulosclerosis.Both C3 and F.D.P. excretion showed considerable variation with time, with parellel fluctuations in the two antigens. These fluctuations did not depend on the total protein leakage and suggest that the complement and clotting sequence are closely related in these glomerular disorders.

Antigens↗
PubMed1973

Identification of intrarenal fibrin deposition.

The site and extent of intrarenal fibrin deposition has been examined by routine histological staining, immunofluorescence, and electron microscopy in 109 patients with a wide variety of renal diseases. The findings have been correlated with the amount of urinary fibrin/fibrinogen degradation product (FDP) excretion as measured by the tanned red cell haemagglutination inhibition immunoassay. The results show that routine histological stains (Martius Scarlet Blue and Picro Mallory) are unreliable, particularly where there is mesangial accumulation of material or where the amount of fibrin deposited is small and confined to a subendothelial position. Similarly the electron microscope may overassess the degree of fibrin deposition, particularly if this is associated with the deposition of immunoglobulins and complement. There is a close relationship between the site and extent of fibrin, as detected by immunofluorescence, and the maximal urinary FDP excretion.

Adult↗