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Aim: The aim of this study was to investigate the effect of a high salt (HS) diet on age-related changes in blood pressure (BP) and the possible role played by regulatory central mechanisms., Methods: Young (5 months) and old (27 months) male Fischer 344 × Brown Norway (F344/BN) rats were fed standard chow or 8% HS diet for 12 days. BP and heart rate (HR) were measured by telemetry., Results: Mean arterial BP (MAP) was significantly elevated in old rats during the day and night when compared with young animals. The HS diet further elevated MAP in both age groups, and the increase was more pronounced in the old animals, while HR was not altered by age or HS diet. In addition, cardiovascular responses to restraint stress were diminished in the old when compared with the young and were unchanged with HS diet in either age group. Both age and the HS diet elevated the adrenomedullary mRNA levels of tyrosine hydroxylase, an indicator for sympathoexcitation. HS diet enhanced intracerebroventricular angiotensin II (AngII)-induced BP and HR elevations in both age groups. AngII type 1 receptor mRNA increased significantly in the hypothalamus with age and HS diet. Furthermore, hypothalamic p22phox mRNA and gp91phox protein, subunits of NADPH oxidase, as well as NADPH oxidase activity increased with the HS diet in the old animals, whereas antioxidant enzymes that decreased with age yet remained unaltered with the HS diet., Conclusion: Our findings indicate that sensitivity of BP to HS diet increases with age, and that central AngII-induced pressor responses are diminished in old rats compared with the young both under control conditions and during HS diet treatment. These changes are paralleled by increases in the expression and NADPH oxidase activity in the hypothalamus, possibly leading to central oxidative stress-mediated sympathoexcitation and high BP., (© 2017 S. Karger AG, Basel.)

Background: Various immunological abnormalities leading to impaired immune status have been described in uraemic adults; however, few data are available for uraemic children., Methods: In this study, peripheral blood total lymphocyte count and lymphocyte subsets (CD3+, CD4+, CD8+, CD16+, CD20+) were evaluated, skin tests with PPD and Candida antigens were performed, and serum immunoglobulin (IgG, IgA, IgM) and complement (C3, C4) levels were measured in 30 children with end-stage renal failure (10 before dialysis, 10 on continuous ambulatory peritoneal dialysis, and 10 on haemodialysis) and the results compared with those of 15 healthy controls., Results: The data showed significant lymphopenia in predialysis and haemodialysis groups. No significant change was observed in the CD4+/CD8+ ratio or in the percentages of lymphocyte subsets in either group studied, while the absolute values of some lymphocyte subsets were significantly lower in all groups as compared with controls. In skin test evaluation, only the patients in the predialysis group showed a significantly decreased response to Candida antigen. The serum immunoglobulin levels were significantly decreased in the continuous ambulatory peritoneal dialysis group as compared with the control group., Conclusion: Our results, together with those of other paediatric studies, reported in the literature, suggest that uraemic children are not immunocompromised, though the effects of uraemia may cause some variation in their immune status., (Copyright 2001 S. Karger AG, Basel.)

Chronic exposure to cold (5 degrees C) is well known to increase both tyrosine hydroxylase (TH) activity in brown adipose tissue and systemic blood pressure. The effect of chronic dietary administration of the alpha-adrenergic antagonist, prazosin, and the amino acid, L-arginine, on both the elevation of blood pressure during exposure to cold and on TH activity and expression of TH mRNA in the adrenal glands of rats was studied. As observed previously, chronic exposure to cold increased systolic blood pressure significantly and induced cardiac hypertrophy. Chronic dietary treatment with prazosin (8 mg/kg food) and arginine (20 g/kg food) returned blood pressure to control levels, did not affect body weight significantly, but failed to prevent cardiac hypertrophy. Both prazosin and L-arginine reduced the drinking response to administration of angiotensin II. Treatment with arginine and prazosin was accompanied by a significant increase in the urinary outputs of dopamine and L-DOPA. The 3 cold-treated groups (control, L-arginine and prazosin) had increases in plasma T3 and decreases in plasma T4 and plasma renin activity. Plasma concentrations of epinephrine and norepinephrine were increased significantly in the L-arginine-treated group. TH mRNA and TH activity in the adrenal glands were increased in the 3 cold-treated groups and these measures were correlated directly and significantly with plasma norepinephrine and epinephrine concentrations. Although both prazosin and arginine prevented the cold-induced elevation of blood pressure, they did not prevent the increase in TH mRNA, TH activity or epinephrine in plasma. The protective effect of arginine and prazosin in cold-induced hypertension may be related both to their reduction in plasma renin activity and to a reduced responsiveness to angiotensin II, as well as to their abilities to increase the secretion of dopamine.

The effect on growth of long-term treatment with prednisolone was studied in 12 patients with steroid-sensitive nephrotic syndrome. Our patient's heights were found between the 10th and 25th percentile both at the first and last height measurement. There was no statistical difference between the first and last height standard deviation score (Ht SDS) (p greater than 0.05). When compared with chronological age, growth velocity (GV), GV SDS and bone age were found low but within the normal range for this age group. There was not any correlation between the last Ht SDS and relapse number, total doses and duration of daily and alternate-day steroid therapy (p greater than 0.05). Growth hormone (GH) responses to pharmacological stimuli were obtained as severe deficiency in 10 patients, partial deficiency in 1 patient and normal level in 1. There was statistical difference between the pulse number of the overnight GH profile of the patients and control group (p less than 0.05). But no statistical difference was found between GH pulse amplitude and GH concentration in patients and control group (p greater than 0.05).