Montreal Children's Hospital

About: Montreal Children's Hospital is a healthcare organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 3842 authors who have published 4816 publications receiving 200198 citations.

Natural history and surgical outcomes for isolated discrete subaortic stenosis in children

Abstract: OBJECTIVE—To document the natural history and surgical outcomes for discrete subaortic stenosis in children. DESIGN—Retrospective review. SETTING—Tertiary care paediatric cardiology centres. PATIENTS—92 children diagnosed between 1985 and 1998. MAIN OUTCOME MEASURES—Echocardiographic left ventricular outflow gradient (echograd), and aortic insufficiency (AI). RESULTS—The mean (SEM) age at diagnosis was 5.3 (0.4) years; the mean echograd was 30 (2) mm Hg, with AI in 22% (19/87) of patients. The echograd and incidence of AI increased to 35 (3) mm Hg and 53% (36/68) (p < 0.05) 3.6 (0.3) years later. The echograd at diagnosis predicted echograd progression and appearance of AI. 42 patients underwent surgery 2.2 (0.4) years after diagnosis. Preoperatively echograd and AI incidence increased to 58 (6) mm Hg and 76% (19/25) (p < 0.05). The echograd was 26 (4) mm Hg 3.7 (0.4) years postoperatively, with AI in 82% (31/38) of patients. Surgical morbidities included complete heart block, need for prosthetic valves, and iatrogenic ventricular septal defects. Eight patients underwent reoperation for recurrent subaortic stenosis. The age at diagnosis of 44 patients followed medically and 42 patients operated on did not differ (5.5 (0.6) v 5.0 (0.6) years, p < 0.05). However, the echograd at diagnosis in the former was less (21 (2) v 40 (5) mm Hg, p < 0.05) and did not increase (23 (2) mm Hg) despite longer follow up (4.1 (0.4) v 2.2 (0.4) years, p < 0.05). The incidence of AI at diagnosis and at last medical follow up was also less (14% (6/44) v 34% (13/38); 40% (17/43) v 76% (19/25), p < 0.05). CONCLUSIONS—Many children with mild subaortic stenosis exhibit little progression of obstruction or AI and need not undergo immediate surgery. Others with more severe subaortic stenosis may progress precipitously and will benefit from early resection despite risks of surgical morbidity and recurrence. Keywords: subaortic stenosis; congenital heart disease; cardiac surgery

Social policy as a cause of childhood accidents: the children of lone mothers.

Abstract: Almost one in five British mothers is a lone mother. Their children have injury rates that are twice those of children in two parent families. In this article the link between lone parenthood and childhood injury is examined. The increased injury rates for the children of lone mothers can be explained by the poverty, poor housing conditions, and social isolation of lone mothers in Britain. The problem of reconciling the demands of paid work with the demands of the unpaid work of childrearing is particularly difficult for lone mothers, who find themselves in a benefit dependent poverty trap. Many such mothers would seek paid work if affordable day care were available. Day care would also provide a safe environment for their children, who are otherwise exposed to the environmental hazards of poor housing. Provision of day care is a social policy that would have important effects on the health and welfare of lone mothers and their children. These effects deserve to be properly evaluated. Since the early 1970s the number of one parent families in Britain has increased by between 30000 and 40000 a year. Currently there are over one million lone parent families in Britain, about 21% of all families with children. Nine out of 10 of these families are headed by a mother.1 The children of lone mothers have the highest death rates of all social groups. In a reanalysis of British census data, the children of “unoccupied” parents, of whom an estimated 89% are unemployed single mothers, had a death rate 42% higher than children in social class V, the poorest socioeconomic group.2 Injuries were responsible for 60% of the deaths among the children of lone mothers.2 The strong association between single parenthood and risk of childhood injury is well established from epidemiological studies. …

Mechanisms of impaired growth hormone secretion in genetically obese Zucker rats: roles of growth hormone-releasing factor and somatostatin.

Abstract: GH secretion is markedly blunted in obesity; however, the mechanism(s) mediating this response remains to be elucidated. In the present study we examined the involvement of the two hypothalamic GH-regulatory hormones, GH-releasing factor (GRF) and somatostatin (SRIF), using the genetically obese male Zucker rat. Spontaneous GH, insulin, and glucose secretory profiles obtained from free moving, chronically cannulated rats revealed a marked suppression in amplitude and duration of GH pulses in obese Zucker rats compared to their lean littermates (mean 6-h plasma GH level, 3.9 ± 0.4 us. 21.5 ± 3.8 ng/ml; P < 0.001). Obese rats also exhibited significant hyperinsulinemia in the presence of normoglycemia. The plasma GH response to an iv bolus of 1 ng rat GRF-(1-29) NH2, administered during peak and trough periods of the GH rhythm, was significantly attenuated in obese rats at peak (137.4 ± 26.1 vs. 266.9 ± 40.7 ng/ml; P < 0.02), although not at trough, times. Passive immunization of obese rats with a specific ...

Moderately high intake of folic acid has a negative impact on mouse embryonic development

Abstract: BACKGROUND The incidence of neural tube defects has diminished considerably since the implementation of food fortification with folic acid (FA) However, the impact of excess FA intake, particularly during pregnancy, requires investigation In a recent study, we reported that a diet supplemented with 20-fold higher FA than the recommended intake for rodents had adverse effects on embryonic mouse development at embryonic days (E)105 and 145 In this report, we examined developmental outcomes in E145 embryos after administering a diet supplemented with 10-fold higher FA than recommended to pregnant mice with and without a mild deficiency of methylenetetrahydrofolate reductase (MTHFR) METHODS Pregnant mice with or without a deficiency in MTHFR were fed a control diet (recommended FA intake of 2 mg/kg diet for rodents) or an FA-supplemented diet (FASD; 10-fold higher than the recommended intake [20 mg/kg diet]) At E145, mice were examined for embryonic loss and growth retardation, and hearts were assessed for defects and for ventricular wall thickness RESULTS Maternal FA supplementation was associated with embryonic loss, embryonic delays, a higher incidence of ventricular septal defects, and thinner left and right ventricular walls, compared to mothers fed control diet CONCLUSIONS Our work suggests that even moderately high levels of FA supplementation may adversely affect fetal mouse development Additional studies are warranted to evaluate the impact of high folate intake in pregnant women Birth Defects Research (Part A), 2013 © 2012 Wiley Periodicals, Inc

Maternal Cigarette Smoking and Fetal Oxygen Transport: A Study of P50, 2,3-Diphosphoglycerate, Total Hemoglobin, Hematocrit, and Type F Hemoglobin in Fetal Blood

Abstract: The current study was undertaken to determine whether the O2 carrying capacity of newborns born to mothers who smoke can accommodate to carbon monoxide poisoning to compensate for the potential tissue hypoxia induced by CO From a cohort of 1,222 women and newborn infants the total hemogloblin concentration, hematocrit, and carboxyhemoglobin (HbCO) were measured and analyzed with regard to the maternal HbCO level and the number of cigarettes smoked per day Also, for 100 pairs of mothers, of whom 50 were smokers and 50 nonsmokers, and their newborns, measurements were made of the intraerythrocyte concentration of 2,3-diphosphoglycerate (2,3-DPG), the hemoglobin concentration, and the affinity of hemoglobin for oxygen by determination of O2 tension for 50% of Hb-O2 saturation (P50) The results showed no significant relationship between smoking habits of mothers and their levels of hemoglobin, P50, and 2,3-DPG; only the hematocrit was slightly increased in smoking mothers However, in fetal blood a significant correlation was found between the number of cigarettes smoked per day and levels of hemoglobin, hematocrit, and P50 The P50 decreased in relationship to the increase in maternal HbCO The P50 change was brought about by an increase in hemoglobin F found in the fetuses of mothers who smoked Although all these changes were statistically significant, these mechanisms of acclimatization to CO poisoning appeared trivial in magnitude It is concluded that the human fetus does not have a biologic capacity to accommodate to maternal cigarette smoking, and therefore the fetus is particularly susceptible to the adverse effects of cigarette smoking