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Biomedical subjects

M S Knapp

Publications and source records attributed to M S Knapp.

At least 19 recordsLinked to original sources
PubMed1979

Possible effect of time on renal allograft rejection.

The change in plasma creatinine concentrations from decreasing values after successful renal transplantation to increasing values after the onset of rejection occurs as a sudden event. Twenty-two such episodes in 16 renal allograft recipients were studied by extrapolating sequential measurements of plasma creatinine concentrations to see when the change occurred. Seventeen of the episodes occurred between 2300 and 1100 and the rest at other times. This difference was significant. The results suggest that rejection is more common at night and apparently has a circadian rhythm, being likely to first influence creatinine clearance at around 0600.

Circadian Rhythm↗
PubMed1979

The time of day of antigen encounter influences the magnitude of the immune response.

Studies in the rat and in man have shown that the time of day at which an antigen is encountered has an influence on the expression of any subsequent cell-mediated immunity, when the response is measured after a fixed interval. This suggests that immune processes are modulated by intrinsic biological rhythms. Experiments are now reported in which sensitized rats were ear-challenged with oxazolone and studied at intervals during the delayed hypersensitivity reaction. These show that differences in the expression of immunity due to the clock time of challenge became apparent at an early stage and were still present after the maximum response, assessed by the change in ear thickness. The experiments also show that the circadian variations in antigen responsiveness are present during the second recall of immunity and can be manipulated by altering the lighting regimen. The light-dark cycle is often a synchronizer for biological rhythms, although its precise role in the oxazolone system remains to be evaluated. This study demonstrates that phase reversal of the lighting regimen alters the proportions of lymphocytes present in rat blood at two clock times, one of which is the time of day at which the maximum immune response to oxazolone is initiated.

Animals↗
PubMed1978

Blood transfusion and renal allograft survival.

Thirty-two first renal transplantations with cadaveric allografts were reviewed to see how many of the recipients had received blood transfusions preoperatively. There was a significant difference in transplant survival between patients who had and patients who had not received blood transfusion before transplantation; this difference was entirely due to acute rejection within three months after transplantation in patients who had not received transfusion. Other factors studied had no effect on survival.

Blood Transfusion↗
PubMed1978

Circadian rhythmicity of delayed hypersensitivity to oxazolone in the rat.

1. A marked circadian rhythm was detected in the ear swelling of rats immunized and then challenged with oxazolone. 2. The peak response observed at 10.00 hours was over eight times the minimum at 16.00 hours. 3. As related tests are used frequently in man greater attention to clock time is necessary in clinical immunology.

Animals↗
PubMed1978

Transplantation, immunosuppression and plasmapheresis in Goodpasture's syndrome.

Renal transplantation in the face of circulating anti-glomerular basement membrane (GBM) antibody can lead to recurrent glomerulonephritis. The severity of the recurrence may be related to the level of antibody present at the time of transplantation. We describe a patient with Goodpasture's Syndrome and moderate circulating anti-GBM antibody activity who received a renal transplant, followed by plasmapheresis and immunosuppression. The graft has functioned well for almost two years associated with a continued reduction in levels of circulating anti-GBM antibody.

Adult↗
PubMed1978

Analgesic nephropathy: an important cause of chronic renal failure.

Study of case-notes and autopsy reports of patients with renal disease suggests that analgesic nephropathy is responsible for at least 12 per cent of cases of chronic renal failure, Between 1970 and 1975 eight new cases of analgesic nephropathy were seen annually in a population of three-quarters of a million. This is equivalent to an incidence of 490 new cases per year in England and Wales. Fifty-five patients with analgesic nephropathy were followed from one to 84 months for a total of 190 patient years. Changes in renal function were correlated with bacteriuria, hypertension and analgesic consumption. One-third of the cases had been misdiagnosed and analgesic abuse was only revealed by thorough examination of case-notes and autopsy records, together with careful questioning of patients and relatives. A number of cases had been classified as chronic pyelonephritis. The calculated survival rate at five years was 44 per cent. Mortality was related to the level of analgesic consumption and the degree of renal failure at the time of diagnosis. The prognosis was poor if serum creatinine at presentation was greater than 400 mumol/l. There was no significant correlation between deterioration in renal function and bacteriuria or hypertension. Forty-two per cent of the patients were taking analgesics for arthritis; 27 per cent had rheumatoid arthritis. Most had been taking large quantities of analgesic mixtures containing phenacetin. Renal papillary necrosis was present in only 26 per cent on intravenous urography but was found in all those examined at autopsy. Twenty thousand, two hundred and twenty-nine autopsy reports were examined for the presence of renal disease. Renal papillary necrosis was found in 0.41 per cent, and could be attributed to analgesic nephropathy in 24 per cent. In patients under 65 years of age analgesic nephropathy appeared to be a more frequent cause of death than chronic pyelonephritis. The report indicates the need for careful enquiry about analgesic consumption in all patients with renal disease, and emphasizes the importance of early diagnosis and cessation of analgesics in suspected cases of analgesic nephropathy.

Adult↗