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Biomedical subjects

J C Mackenzie

Publications and source records attributed to J C Mackenzie.

At least 37 records · Page 2Linked to original sources
PubMed1986

Atrial natriuretic peptide: physiological release associated with natriuresis during water immersion in man.

Thermoneutral water immersion produces a physiological increase of thoracic blood volume, raises central venous pressure and increases urinary sodium excretion by a hitherto ill-understood mechanism. We have investigated whether this enhanced sodium excretion could be mediated by the recently discovered natriuretic factor, atrial natriuretic peptide (ANP). During water immersion there was a highly significant (P less than 0.001) twofold increase of the mean plasma ANP concentration and a doubling of the mean urinary sodium excretion. Both were unchanged during the control experiments. These results are consistent with the hypotheses that ANP is released into plasma in response to central blood volume expansion and that it functions as a natriuretic hormone in normal man under physiological conditions.

Adult↗
PubMed1985

Influence of angiotensin II on the concentration of arterial plasma electrolytes in anaesthetized sheep.

Angiotensin II and I significantly raised potassium and lowered sodium and chloride ion concentrations in arterial plasma, with peak changes occurring in the first 2 min of a 6-min infusion period. The octapeptide increased the arterial K+ level in a dose-dependent manner, but the response showed tachyphylaxis when multiple infusions of 6-min duration were administered after a recovery interval of only 5 min. Raising the arterial blood pressure by 20-33 mmHg with adrenaline and noradrenaline failed to account for the increase in arterial plasma K+ concentration produced by the two peptides. These findings, in particular the rise in K+ concentration, are discussed in relation to possible mechanisms by which angiotensin II affects arteriolar tone.

Angiotensin I↗
PubMed1985

Ten years' experience of an amyloid clinic--a clinicopathological survey.

The aetiology, clinical course and affected organs were studied in 124 patients with acquired systemic amyloidosis and seven patients with organ-limited amyloid deposits. Seventy-five patients had reactive systemic AA amyloidosis, which was associated with rheumatic disease in 55 and with chronic infection in 13 cases. Forty-nine patients had systemic AL amyloidosis. Thirteen of these cases were associated with myelomatosis and 11 with non-malignant immunocyte dyscrasias. In 25 patients with systemic AL disease no immunocyte dyscrasia was identified. Renal involvement dominated the clinical course of both forms of systemic amyloidosis, and renal failure was the most common cause of death. Gastrointestinal disturbance and hepatosplenomegaly were found in both AA and AL disease, although differences were noted in the distribution of amyloid protein within rectal biopsies. Amyloid cardiomyopathy, neuropathy and macroglossia were present in patients with AL amyloidosis only. These clinical patterns were reflected by tissue distribution at necropsy in 67 patients.

Adolescent↗
PubMed1984

Glomerulonephritis, non-Hodgkin's lymphoma and leucocytoclastic vasculitis.

2 cases of active focal proliferative glomerulonephritis, lymphocytic malignant lymphoma and leucocytoclastic vasculitis are described. 1 presented with the nephrotic syndrome and progressive renal impairment, the other with acute renal failure. Cryoglobulins were detected in the serum of 1 patient, but not in that of the other. Initial renal and skin biopsies in the 2 patients were strikingly similar. As well as demonstrating glomerular lesions, the renal biopsies contained interstitial lymphomatous infiltrate which, in 1 case, was initially incorrectly interpreted and resulted in delay in specific treatment. Immunosuppressive therapy markedly improved renal function and induced remission of the vasculitis and lymphoma. Repeat renal biopsy in 1 case confirmed regression of the glomerulonephritis. A common immunological aetiology may explain the co-existence of these three conditions in the 2 patients.

Biopsy↗
PubMed1984

Renal biopsy in the elderly: clinicopathological correlations in 143 patients.

The clinical presentation and spectrum of renal histopathology is described in 143 patients aged 60 years or more, with renal disease. In 82 patients renal biopsy revealed primary renal disease. In the remainder, changes associated with systemic conditions were found. These included amyloidosis, polyarteritis nodosa and hypertension. Fifty patients present with the nephrotic syndrome, one third of whom had a membranous glomerulonephritis on the renal biopsy. Three patients had a carcinoma associated with this renal histology. Two patients had a minimal change lesion and their nephrotic syndrome responded to corticosteroids. Renal biopsies from the 45 patients present with renal failure revealed a variety of histopathology which included idiopathic crescentic nephritis and antiglomerular basement membrane disease. Percutaneous renal biopsy is a valuable diagnostic aid in elderly patients with renal disease.

Age Factors↗
PubMed1983

Long-term effects of endralazine (BQ-22-708) in patients with renal impairment and hypertension.

Endralazine, a new peripheral vasodilator, was studied in 21 patients with hypertension and chronic renal failure. Nineteen patients had unacceptable control of hypertension with their previous therapy, and 2 were suffering adverse effects for other third line drugs. All patients continued to receive a beta-adrenergic blocking agent. Five patients failed to complete the study, two because of poor compliance, and 3 as a result of failure to control raised blood pressure. In the remaining 16 patients, satisfactory blood pressure reduction was seen at 6 months and was maintained in 12 patients followed for 18 months. Endralazine was well tolerated. No patient developed the lupus syndrome nor evidence of drug-induced immunological abnormality.

Adult↗
PubMed1983

Renal involvement in systemic amyloidosis.

In a study of 124 patients with systemic amyloidosis, renal involvement was the major presenting feature in 68 per cent of patients with AA and 42 per cent with AL disease. Renal failure contributed to the deaths of 72 per cent and 33 per cent of patients respectively. In 23 renal biopsies from patients with AA disease, quantitative glomerular amyloid infiltration correlated with urinary protein excretion and with serum creatinine. Seven of these patients had repeat biopsies; change in glomerular amyloid correlated with changes in both renal function and proteinuria. Four patients with end-stage renal amyloidosis have been successfully managed on CAPD for 37 patient months.

Adolescent↗
PubMed1979

A renal biopsy study in toxaemia of pregnancy.

Renal biopsy specimens from 11 women with severe pre-eclamptic toxaemia were examined by light and electron microscopy linked with immunofluorescence and immuno-electron microscopy. The part played by the mesangium in causing capillary loop thickening is stressed, and the progress of this 'strangulation' is illustrated. In contrast to the findings of most previous authors, IgM was demonstrated by direct immunofluorescence in all biopsy specimens, and its presence and site within the glomerulus were shown by immuno-electron microscopy in three cases.

Adult↗
PubMed1977

Radioimmunoassay of unprocessed sheep blood extracts to follow angiotensin metabolism.

The acceptability of radioimmunoassay to determine the levels of compounds antigenic to anti-angiotensin antibodies, in unprocessed methanolic blood extracts, was established for sheep blood. This approach was used to follow the clearance of antigenic compounds after administration of angiotensins I and II and fragments of angiotensin II in anesthetized sheep. The organs supplied by the systemic circulation and also the lungs effectively removed angiotensin I, but the removal of octapeptide occurred only in the peripheral tissues. The blood concentrations of compounds reacting with the anti-angiotensin II antibody always increased with passage of angiotensin I through the pulmonary circulation but not with passage of angiotensin II. The results indicate that factors other than efficiency of removal by the tissue is important in establishing blood levels. The sites of administration and of sampling were shown to be important in relation to ratios of the concentrations of antigenic material. There was a similar uptake of both hormones in the kidney; the relative inability of angiotensin I to reduce renal blood flow, therefore, does not result from a failure of uptake.

Angiotensin I↗
PubMed1976

Penicillamine nephropathy in rheumatoid arthritis. A clinical, pathological and immunological study.

Fourteen patients who developed persistent proteinuria while on penicillamine for rheumatoid arthritis, were collected over a period of one year. Eleven patients had a frank nephrotic syndrome and three had a lesser degree of proteinuria but no oedema. The patients had received penicillamine (mean daily dose 1015 mg) for less than one year (mean 7-5 months) when the nephropathy was detected. Clinical investigations have been correlated with renal biopsy material. Light microscopy detected no abnormalities except for minimal hypercellularity in a few patients. In markde contrast, the electron-microscope revealed numerous electron-dense deposits (EED's) in the outer layer of the basement membrane. Immunofluorescence showed the presence of IgG and complement in the basement membrane, the intensity of which correlated with the number of EED's. The pathological picture was essentially the same in those patients with the nephrotic syndrome and those with proteinuria. In this series, we found no evidence that penicillamine induced renal damage by any other mechanism except immune complex deposition. Serological tests revealed little evidence for complement activation or consumption and platelet aggregation was the only positive direct test for circulating immune complexes. Renal biopsies were performed at differing intervals after the cessation of penicillamine therapy, which allowed assessment of the natural history of the pathological lesion and revealed a striking persistence of EDD's in some patients. Two patients showed an almost identical picture initially and at re-biopsy one year later. Persistent proteinuria was also a feature of the group as a whole. The pathological picture has similarities with that of idiopathic membranous glomerulopathy. This study suggests that the use of penicillamine in rheumatoid arthritis may induce persistent renal damage.

Adult↗
PubMed1976

Undried cellulose gel film-- a high permeability dialysis membrane.

Undried cellulose gel film manufactured by British Cellophane Ltd (BCL) has been evaluated in vivo and in vitro. Results obtained indicate that undried cellulose gel film is superior in terms of ultrafiltration and middle molecular clearance to the widely used Cuprophan membrane and comparable with the Rhône Poulenc AN69 Acrylopolynitrile membrane for middle molecular clearance. The gel film is suitable for use with conventional dialysis equipment and in terms of residual blood volume, leak rate and pyrogenicity is indistinguishable from cuprophan.

Cellulose↗