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This study indirectly examined the role of prostanoids (PG) in mediating rat mesangial cell (MC) DNA synthesis induced by hydrogen peroxide (H2O2), interleukin 6 (IL-6), and platelet-derived growth factor (PDGF). MC were exposed to three daily pulses of 10(-6) mol/l H2O2 alone or in combination with IL-6 (5 ng/ml) or PDGF (10 ng/ml). In order to examine (indirectly) the role of PG in mediating changes in MC DNA synthesis, indomethacin (1.5 x 10(-5) mol/l) or the thromboxane A2 synthetase inhibitor Dazmegrel (10(-5) mol/l) was added to the medium and DNA synthesis assessed after 72 h using 3H-thymidine incorporation (3H-TdR). Stimulation of MC by H2O2 alone resulted in an increase in 3H-TdR of 34.7 +/- 5.5% (p < 0.01). H2O2 enhanced the mitogenic effects of IL-6 and PDGF, 3H-TdR increasing by 52 +/- 12.1% (p < 0.01) and 100 +/- 21% (p < 0.001), respectively. Indomethacin suppressed the DNA synthesis induced by H2O2 alone, 3H-TdR decreasing by 33 +/- 12% (p < 0.05). Indomethacin also reduced the mitogenic response to H2O2 plus IL-6 and H2O2 plus PDGF by 91 +/- 17 and 97 +/- 12%, respectively (p < 0.05). Dazmegrel reduced 3H-TdR when MC were exposed to H2O2 alone by 31.8 +/- 16% (p < 0.05) and when combined with IL-6 or PDGF by 80 +/- 26 and 120 +/- 13%, respectively (p < 0.05). These data suggest that the pathways through which H2O2-induced growth of MC is mediated appear, at least in part, to involve PG, particularly thromboxane A2.

Angiographic and histological studies of the intrarenal circulation have been undertaken in 20 patients following complicated pregnancies: 12 patients had had hypertension of pregnancy (group 1); 7 acute renal failure due to either ante- or post-partum haemorrhage and 1 patient post-partum renal failure (group 2). 3 months after delivery all patients had angiographic evidence of structural and functional abnormalities involving intrarenal blood vessels and cortical blood flow. The severity of the structural changes was related to the degree of microangiopathic haemolytic anaemia noted in the acute obstetric complication but not to the height of the blood pressure at this stage. Histological abnormalities of the cortical blood vessels were minimal. At the time of the renal angiogram and biopsy, 3 of the 12 group 1 patients were hypertensive and 3 had impaired renal function, compared with 5 and 1, respectively, in the 8 group 2 patients. Although during the follow-up period (mean 5 years) no further deterioration in renal function in either group has been observed, hypertension developed in 50% of the group 1 patients compared with only 1 of the patients in group 2. The relationship between the late onset of hypertension and the intrarenal vascular and haemodynamic abnormalities is discussed.

The histological appearances of the proximal and peripheral intrarenal arteries and renal cortex have been examined in 3 patients who underwent nephrectomy for intractable pain associated with the loin-pain-haematuria syndrome. Marked 'atherosclerotic' changes were noted to involve segmental, lobar, interlobar and arcuate arteries with evidence in one kidney of early microaneurysmal formation. These lesions of the more proximal intrarenal arteries were associated with occlusive lesions of the interlobular arteries, areas of cortical ischaemia and cortical infarcts consistent with the changes resulting from microemboli. The histological appearances correlated well with previously described angiographic findings.

The effect of an isotonic saline infusion on urinary sodium excretion and plasma renin activity (PRA) has been studied in 11 normotensive patients with a previous history of pregnancy-associated hypertension. The results have been compared with a group of controls matched for age, sex and parity. The results demonstrate an exaggerated natriuresis and a suppressed PRA response in the patients with a previous history or pregnancy-associated hypertension which is similar to those reported in patients with established 'essential' hypertension.