Jean-Guy Mongeau

LONG-TERM FOLLOW-UP OF PATIENTS WHO UNDERWENT UNILATERAL NEPHRECTOMY IN CHILDHOOD

The long-term damaging potential of remnant nephron hyperperfusion was investigated in patients who had undergone unilateral nephrectomy in childhood. 27 such patients were examined after a mean of 23.3 years postnephrectomy. The average creatinine clearance was 83.9 +/- 16.5 ml/min/1.73 m2 or 74.3% of that in healthy controls with two kidneys; it was a value similar to that reported 3 to 6 months postnephrectomy in kidney donors. Age at the time of nephrectomy, duration of follow-up, or sex had no influence on the residual creatinine clearance. None of these patients had clinically important hypertension or proteinuria. Since so little evidence of kidney damage could be documented after such a long observation period, hyperperfusion would seem to be seldom of clinical importance in man unless other factors were present.

Familial resemblance of body weight and weight/height in 374 homes with adopted children.

Body weight and weight/height were measured in 535 children adopted at the median age of 3 months, and in 250 natural children in French-Canadian origin living in 374 Montreal homes, to determine whether the shared environment contributed to the familial resemblance of weight in children aged one to 21. The mid-parent vs natural childrens correlation ( r2 X 100) was 9.55% for body weight and 6.60% for W/H (p less than 0.01), whereas the mid-parent vs adopted childrens correlation was 0.00% for both characteristics. The sib-sib correlation in 80 homes with greater than 1 natural child was 15.2% for weight and 13.48% for W/H (p less than 0.001), whereas in 138 homes with greater than 1 adopted child, the adoptee-adoptee correlations were, respectively, 0.00% and 0.07%. It is concluded that heredity explains most of the familial aggregation of patterns of weight and weight/height in children. This conclusion does not necessarily apply to obesity, since weight indices in children do not accurately reflect excess fat tissue, and half of the adoptees were adopted after the age of three months.

THE INFLUENCE OF GENETICS AND HOUSEHOLD ENVIRONMENT UPON THE VARIABILITY OF NORMAL BLOOD PRESSURE: THE MONTREAL ADOPTION SURVEY

The Montreal Adoption Survey was conducted as a cross-sectional epidemiologic study of cardiovascular risk factors in French Canadian families. Analysis included blood pressure readings of 756 adopted and 445 natural children as well as 1176 parents. A genetic model was applied to the analysis of our data. Interindividual variability of blood pressure was studied and observed correlatives of systolic and diastolic pressure of parental and non parental subjects were calculated. Based on the maximum likelihood estimates presented in the models the explanation of the parent offspring and the between sibs expected population correlatives for systolic blood pressure was the following: 61% was due to shared genes and 39% to environment shared by both parents and children. For diastolic blood pressure the explanation between parents and offspring was the following: 58% was due to shared genes and 42% due to shared environment across generation. The explanation between sibs was estimated to be the following: 33% due to generation, 24% to shared environment across generation and 43% to shared environment within generation.

Familial aggregation of blood pressure and its components.

The well known existence of familial clustering of blood pressure among adults raises two important questions: At what age does this aggregation become significant? Are either shared environment or heredity or both the responsible components?

Clinical efficacy of levamisole in the treatment of primary nephrosis in children

The purpose of the study was to evaluate the efficacy and the toxicity of levamisole given for 1 year to 16 children suffering from minimal change primary nephrosis who were relapsing frequently. The overall results showed that under levamisole the relapse rate decreased by 55% and the steroid requirements by 50%. After cessation of levamisole administration, most children (11/16) relapsed again. A second course of levamisole treatment reduced the relapse rate significantly once again. At the dosage of 2.5 mg/kg given every other day for 1 year or more, no side effects of levamisole were observed. It is concluded that levamisole does not cure nephrosis but reduces the incidence of relapses for the period it is administered. It also reduces the steroid requirements without any important side effects.

Heredity and blood pressure in humans: an overview.

This paper presents a review of the genetic transmission of normal blood pressure and of essential hypertension. Familial aggregation of normal blood pressure has been reported in adults, in children and even in newborns. Blood pressure aggregation phenomenon, however, is the result of both a genetic component and shared environmental factors. More specific for each etiological factor were the studies of blood pressure aggregation in twins and in adopted children. Attention was focused on the Montreal Adoption Study. In essential hypertension, a Japanese study is reviewed showing the occurrence of hypertension in the offspring of hypertensive parents. The heterogeneity of essential hypertension is underlined and two of the multiple etiological factors are particularly considered for their genetic component: the response to salt intake and erythrocyte cation fluxes. The conclusion from the literature reviewed is that essential hypertension is a polygenic disease transmitted by polygenic systems.

Study of psychosocial parameters related to the survival rate of renal transplantation in children

Abstract. The purpose of the present study was to assess the effect of intelligence, schooling, psychomotor, emotional, and social status on renal graft survival in children. Sixty-two cadaver renal transplant recipients were evaluated retrospectively and the influence of sex, age, weight, and the use of cyclosporin A (CyA) on the success rate of the graft from 1 to 5 years later was analyzed. Psychological and social scores were devised and included as factors predictive of survival of the graft. Univariate analysis showed that the following variables predicted renal graft survival: the use of CyA (P = 0.0002), pre-transplant dialysis (P = 0.04), weight at the time of transplantation (P = 0.072), and psychological scores (P = 0.064). Association analysis demonstrated that pre-transplantation dialysis was only a chance association and therefore the parameter was discarded. Multivariate analysis showed that the predictive parameters were the use of CyA, sex, weight in kilograms, and the psychological score. An equation was then derived from variables that predict the probability that a specific patient’s graft will survive more than t months. This equation is the estimated survival distribution function and is as follow: S (t) = Exp {–Exp[–(0.8882x1–1.827x2+0.037x3–0.1746x4)+ln t–4.7862]} where S (t) = the survival at t months post transplantation, x1 = sex (male 1, female 2), x2 = CyA (yes 1, no 2), x3 = weight in kilograms, and x4 = psychological score. The major impact of psychological factors on renal graft survival was surprising.

Pathogenesis of the essential hypertensions.

The pathogenesis of essential hypertension (EH) is reviewed with a special focus on the development phase or the pre-hypertensive period. Three animal models are presented: the spontaneously hypertensive rat, the Dahls salt-sensitive rat, and the Milan hypertensive rat. Some of the findings in animal models have ispired new fields and technical approaches for studying EH in man. From the original idea of Page, a new mosaic of various etiological parameters serves as a basis for reviewing the multiple facets of EH in man. One must conclude that EH is heterogeneous disease and most likely every single hypertensive patient belongs to a subgroup of the whole population of hypertensives.

Hypertension in children. Patterns of inheritance and implications for screening and management.

This article is a review of current concepts on hypertension in children and adolescents. It discusses the importance of recording blood pressure in childhood, the epidemiologic and etiologic aspects of hypertension, the diagnostic procedures, and finally the approach to therapy.