Acute idiopathic tubulointerstitial nephritis: report of two cases and review of the literature

Two patients who presented with severe renal failure and evidence of generalized proximal tubular dysfunction were found to have severe diffuse acute tubulointerstitial nephritis on renal biopsy. No etiology could be found in either case. Both patients had dramatic improvement in renal function following steroid therapy. In the first reported case of its kind, one patient relapsed when steroids were withdrawn, but improved again with reinstitution of steroid therapy. These cases, as well as others in the literature, show that steroids are effective and may be necessary to improve renal function in some patients with acute idiopathic tubulointerstitial nephritis. Evidence of proximal tubular dysfunction is a clue to the presence of this disorder.     

Revascularization of the renal artery in renovascular hypertension with progressive renal insufficiency

Sixteen patients underwent surgical treatment for severe renovascular hypertension with rapidly progressive renal failure. These patients were assessed preoperatively with the measurement of serum creatinine and blood-urea levels (means 271 +/- 204 mumol/l and 15.6 +/- 10.3 mmol/l respectively), and renal clearances. 5 patients underwent aorto-renal bypass (bilateral in one case) and 11 patients were treated by autotransplantation of the kidney. Operative mortality was 6.2%. Early results were assessed at 1 and 6 months postoperatively. Renal function was normal in 8 patients, improved in 5 (p less than 0.05), unchanged in 1 and worse in 1 by aorto-renal bypass thrombosis. At long-term with a minimum follow-up of 12 months (mean 31 +/- 12 months), the initial improvement in renal function remained steady in 12 patients whilst 1 patient has gone on to hemodialysis. At middle and long-term, 81% of the patients were normotensive without medication or had improved blood pressure (p less than 0.001). These good results confirm the reversibility of renal ischemic lesions and support an aggressive attitude towards the use of revascularization in the surgical treatment of such patients with renovascular hypertension and renal failure.     

Glucocorticoid effects on phenylethanolamine N-methyltransferase (PNMT) in explants of embryonic rat medulla oblongata

Although glucocorticoid hormones have important roles in the development of neurotransmitter systems in cells derived from the neural crest, it is not known whether they have parallel effects on neuronal development in the brain. To address this issue, we have established an in vitro system of fetal medulla oblongata (MO) to follow development of the epinephrine-synthesizing enzyme, phenylethanolamine N-methyltransferase (PNMT). Embryonic MO was explanted from E13 or E18 embryos and maintained for up to 3 weeks. Successful culture of adrenergic neurons was possible only in explants taken from young embryos, since E18 explants failed to develop. In E13 explants, immunoreactivity to both PNMT and tyrosine hydroxylase, the rate limiting enzyme in catecholamine synthesis, was observed. PNMT catalytic activity which was barely detectable at the time of explanation increased markedly during the first week in vitro. To study the effects of glucocorticoids on PNMT development in central neurons, MO explants were grown in glucocorticoid deficient medium in which rat serum from adrenalectomized rats was substituted for human placental serum. Addition of natural glucocorticoids, cortisol or corticosterone, or the mineralcorticoid, deoxycorticosterone, during the third culture week had no effect on PNMT activity. Dexamethasone (DEX), a synthetic glucocorticoid, also had no effect on PNMT during the first or second weeks in culture. However, addition of DEX during the third culture week resulted in a doubling of PNMT activity. However, attempts to block the DEX effect during the third week or to block the increase in PNMT activity during the first week in control cultures with the glucocorticoid receptor antagonist, dexamethasone 21-mesylate, were unsuccessful. These results suggest that PNMT in central neurons does not require glucocorticoids for ontogeny during the embryonic period. This is in contrast to PNMT in adrenal medulla which requires glucocorticoids for normal development during both the embryonic and postnatal periods. More generally, these studies suggest that development of the same neurotransmitter phenotype in brain and periphery may be differentially regulated.     

Sensitivity of the hypothalamo-hypophyseal system to dexamethasone administered at different times of the day in obesity

The paper is concerned with the results of a study of the circadian rhythm of cortisol secretion and sensitivity of the hypothalamohypophyseal system to small doses of dexamethasone administered in different time of a day to patients with obesity. Disturbance of the circadian rhythm of cortisol secretion resulting in change of the nature of cortisol discharge in the second half of a day, was revealed. Three groups of patients were defined with relation to the type of response of the hypothalamohypophyseal system to dexamethasone administration: with normal, paradoxical and hypersensitive reactions. The results of the study of the circadian rhythm and response of the hypothalamohypophyseal system to dexamethasone were indicative of hypothalamic disturbances in obesity. The authors emphasized the relationship between the nature of sensitivity of the hypothalamohypophyseal system to dexamethasone and age at which the disease developed.     

Effects of methylphenidate and d-amphetamine on timing in the rat

Rats were trained to press a lever for food pellets provided according to a fixed interval 60-sec schedule of reinforcement. Probe trials (peak trials) assessed responding over two-min periods with no pellet delivered. The low rates of responding found early and late in probe trials were increased by methylphenidate and 1.0 mg/kg d-amphetamine (rate-dependent effect). Further, the mean time of responding (peak time) was shortened for both drugs (timing effect).     

Time trends of the prevalences of hepatitis B e antigen positives among hepatitis B virus carriers in Japan

In order to examine time trends of the prevalences of HBeAg positives among HBV carriers in Japan, we analysed data on HBeAg of HBsAg positive voluntary blood donors (23,560 males, and 8659 females) at the Osaka Red Cross Blood Centre between January 1977 and March 1984. Age-specific prevalences of HBeAg positives decreased year by year for both sexes, especially for those in their teens and twenties. The prevalences of HBeAg positives decreased with age, but at any given age it was lower for the later than for the earlier birth cohorts. Although reasons for the secular declines are unknown, the findings suggest that the prevalence of HBeAg positives among HBV carriers will continue to decrease in Japan. This, together with the immunization programme implemented this year, may lead to a future reduction in the risk of HBV related liver diseases in Japan.