Nutritional programming of blood pressure and renal morphology

A range of epidemiological evidence from several diverse populations, supports the hypothesis that risk of essential hypertension, coronary heart disease and non-insulin dependent diabetes is, in part, programmed by intrauterine nutritional status. Animal models developed to investigate the mechanisms that are responsible for such programming are becoming more important as challenges to the epidemiological data become more robust. With strong evidence from animal studies it is now widely accepted that maternal nutritional status in pregnancy is a major programming influence upon the fetus. This paper considers the hypothesis that renal structure and function are determined by prenatal nutrition and that this is a key mechanism in the programming of hypertension. The feeding of low protein diets or other insults in pregnancy that have an impact upon the development of cardiovascular functions, also appears to impact upon nephron number. In the sheep nephron number is related to weight at birth following nutrient restriction, and in the rat low protein diets reduce nephron number by approximately 30%. However, it is possible that hypertension and reduced renal reserve merely coincide and are not causally associated. A study of rats fed low protein diets supplemented with additional nitrogen sources found that whilst only glycine could reverse the hypertensive effects of low protein diets, all supplements could normalise nephron number. The evidence thus suggests that prenatal undernutrition may programme renal structure in later life, but that renal programming is not one of the primary mechanisms leading to hypertension.

Intrauterine programming of nephron number: the fetal flaw revisited

A broad range of epidemiological evidence supports the hypothesis that risk of essential hypertension, coronary heart disease and non-insulin dependent diabetes is, in part, determined before birth. This phenomenon, termed programming, is now the subject of intensive investigation in order to determine possible underlying mechanisms. It is widely accepted that maternal nutritional status in pregnancy is a major programming influence upon the fetus. This review considers the hypothesis that nephron number in humans is determined by prenatal nutrition. An increasing number of human studies indicate that the developing kidney is particularly vulnerable to the adverse effects of fetal growth retarding influences. In animals, growth retarding diets or other insults which have an impact upon the development of cardiovascular functions, also appear to impact upon nephron number. However, it is possible that hypertension and reduced renal reserve merely coincide and are not causally associated.

Stiripentol in severe myoclonic epilepsy in infancy: a randomised placebo-controlled syndrome-dedicated trial. STICLO study group

BACKGROUND

Stiripentol is an inhibitor of cytochrome P450 that showed antiepileptic efficacy in severe myoclonic epilepsy in infancy (SMEI) in association with clobazam and valproate in an open study. To confirm these results, 41 children with SMEI were included in a randomised, placebo-controlled, add-on trial.

METHODS

After a baseline period of 1 month, placebo (n=20) or stiripentol (n=21) was added to valproate and clobazam during a double-blind period of 2 months. Patients then received stiripentol in an open fashion. Responders were defined as having more than 50% reduction in the frequency of clonic (or tonic-clonic) seizures during the second month of the double-blind period compared with baseline.

FINDINGS

15 (71%) patients were responders on stiripentol (including nine free of clonic or tonic-clonic seizures), whereas there was only one (5%) on placebo (none were seizure free; stiripentol 95% CI 52.1-90.7 vs placebo 0-14.6). The 95% CI of the difference was 42.2-85.7. Percentage of change from baseline was higher on stiripentol (-69%) than on placebo (+7%), p<0.0001. 21 patients on stiripentol had moderate side-effects (drowsiness, loss of appetite) compared with eight on placebo, but side-effects disappeared when the dose of comedication was decreased in 12 of the 21 cases.

INTERPRETATION

This controlled trial shows the antiepileptic efficacy, of add-on stiripentol in children with SMEI. The results also provide good reason to focus studies on a specific epilepsy syndrome-a small sample of patients is sufficient to show the efficacy that might have been missed in a heterogeneous population.

French multicenter randomized double-blind placebo-controlled trial on nebulized amiloride in cystic fibrosis patients. The Amiloride-AFLM Collaborative Study Group

The effect of amiloride, a sodium channel blocker, has been evaluated in a multicenter randomized double-blind placebo-controlled trial in cystic fibrosis patients more than 5-years-old (n = 137) whose forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV(1)), and forced mid-expiratory flow (FEF(25-75)) were not below 50%, 50%, and 30% of reference values, respectively. Patients were randomly allocated to two parallel groups. Sixty-four patients were chronically colonized with Pseudomonas aeruginosa; they received either amiloride or placebo as a nebulized solution three times daily for 6 months. Routine treatments were continued. Patients chronically colonized with Pseudomonas received nebulized colimycine twice a day for a month during the third and sixth months of treatment. Bronchopulmonary exacerbations were treated in the usual way. The effects of the amiloride treatment were assessed at the end of the 6-month treatment period. The effects on FVC and secondarily on FEV(1), FEF(25-75), the number of days on antibiotic therapy, the Shwachman score, a nutritional index (weight/height(2)), the change in sputum bacterial flora, and nocturnal cough were assessed. For the patients not chronically colonized with Pseudomonas, the effect of the treatment was also evaluated by counting chronic colonizations with pathogens appearing during the trial period. The present study failed to demonstrate any significant benefit of amiloride over placebo on FVC, FEV(1), and the other secondary endpoints in the studied population. Neither the chronically colonized, nor the noncolonized patients benefited. The confidence intervals of the differences between treatment groups indicated small differences that were most likely of no clinical significance. Complementary analyses taking into account the gender, the type of mutation, the subpopulations whose FVC and FEV(1) were below 80% of normal values at the beginning of the study, and also patients less than 10 years old, did not show any statistically or clinically significant improvements following amiloride therapy.

A simple method to estimate the percentage of hybridity in canola (Brassica napus) F1 hybrids

We have developed an efficient PCR-based system that uses RAPD markers for the certification of F1 hybrids of canola. These markers were selected by screening five parental lines used in three crosses X, Y and Z with 131, 131 and 322 primers respectively. Stable DNA fragments that were homozygous and specific to the male inbreds were used to certify F1 hybrid populations. The hybrid production system was based on self-incompatibility (SI) alleles that prevent self-pollination of the female parent. The efficiency of two S-alleles was compared under both field and greenhouse conditions. The percentage of hybridity was estimated in different F1 populations. We found a significant difference between the two alleles for their efficiency in controlling selfing; both alleles were stable under greenhouse conditions, one allele appeared less reliable under field conditions.