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Biomedical subjects

M J Sampson

Publications and source records attributed to M J Sampson.

43 records · Page 3Linked to original sources

Ribosomal RNA synthesis in newly sliced discs of potato tuber.

A burst of ribosomal RNA synthesis is induced in potato tissue by slicing, and continues at a decreasing rate for about 12 hours. Ribosomal RNA synthesis in potato discs is sensitive to puromycin, in contrast to non-ribosomal RNA synthesis. Thus, the influence of puromycin on total RNA synthesis is significant only during the first 12 hours following slicing. The function of RNA made after 12 hours in a puromycin-insensitive manner is unknown. However, it is apparently unrelated to protein synthesis, since it has been shown that total inhibition of RNA synthesis by addition of actinomycin D to potato tissue after 12 hours of aging has no effect upon protein synthesis during the ensuing 12 hours.

Journal Article↗

Lack of relationship between sympathetic nervous system activity, measured by two circulating markers, and blood pressure in diabetic and nondiabetic subjects.

Two putative sympathetic nervous system (SNS) markers, noradrenaline and neuropeptide Y (NPY) were related to 24-h ambulatory blood pressure (BP) in 59 normotensive subjects, 34 non-insulin-dependent diabetics, and 25 controls. Plasma NPY levels were not significantly different between the two groups [non-insulin-dependent (NIDDM) diabetes mellitus 4.33 (3.25-5.78), controls 5.68 (3.39-6.97) p=0.26] as were those of noradrenaline (1.51+/-0.69 versus 1.78+/-0.55; p=0.053). There were correlations, controlled for age and obesity, of plasma NPY with clinic and night time diastolic BP in the control group only (r=0.49 [p=0.013] and r=0.48 [p=0.023] respectively). No similar correlation was found in the NIDDM group, or between plasma noradrenaline and blood pressure in either group. No correlation was found between plasma insulin and NPY or noradrenaline levels. There is a weak independent relationship between NPY and blood pressure in normotensive nondiabetics but not in NIDDM subjects. We found no evidence for the hypothesis that insulin modulates blood pressure through activity of the SNS.

Adult↗

Development of nephropathy in diabetic patients with a single kidney.

Six diabetic patients with either a nephrectomy or a congenitally single kidney, and who later developed diabetic nephropathy, are described. They represent about 3% of our diabetic population with nephropathy, and are the only patients in our clinic population known to have single kidneys. A reduced renal mass may augment the renal glomerular hyperfiltration associated with diabetes mellitus and increase the risk of later developing nephropathy.

Adult↗

Regression of left ventricular hypertrophy with 1 year of antihypertensive treatment in type 1 diabetic patients with early nephropathy.

M-mode echocardiograms were recorded in 22 Type 1 diabetic patients with microalbuminuria (n = 10) or early persistent proteinuria (n = 12). Eight (36%) had both an increased left ventricular mass (males greater than 131 g m-2; females greater than 100 g m-2) and a systolic blood pressure above the 75th centile of the normal blood pressure distribution. These eight patients were treated with antihypertensive drugs, predominantly enalapril, for 1 year. Echocardiograms were repeated after 3 and 12 months. Systolic blood pressure at recruitment was 155 +/- 14 (+/- SD) mmHg, and was significantly lower after 3 months (146 +/- 12 mmHg; p less than 0.05) and 12 months (139 +/- 8 mmHg; p less than 0.005). Diastolic blood pressure did not change significantly. Both intraventricular septal width and left ventricular posterior wall thickness fell progressively and were significantly lower after 12 months treatment (15.0 +/- 2.7 vs 13.0 +/- 2.6 mm, and 10.3 +/- 1.9 vs 8.8 +/- 1.3 mm; both p less than 0.05). Left ventricular mass index was 148 +/- 29 g m-2 at recruitment, but lower after 3 months (131 +/- 25 g m-2; p less than 0.05) and 12 months (132 +/- 26 g m-2; p less than 0.005) antihypertensive therapy.

Adult↗