A new template to study callosal growth shows specific growth in anterior and posterior regions of the corpus callosum in early childhood.

Most of the studies conducted on the development of the corpus callosum (CC) have been limited to a relatively simple assessment of callosal area, providing an estimation of the size of the CC in two dimensions rather than its actual measurement. The goal of this study was to revisit callosal development in childhood and adolescence by using a three-dimensional (3D) magnetic resonance imaging template of the CC that considers the horizontal width of the CC and compares this with the two-dimensional (2D) callosal area. We mapped callosal growth in a large sample of youths followed longitudinally (N = 370 at T1; N = 304 at T2; and N = 246 at T3). Both techniques were based on a five-section subdivision of the CC. The results obtained with the 3D method revealed that the rate of CC growth over a 4-year period in the rostrum, the genu, the anterior body and the splenium was significantly higher in the youngest age group (< 7 years) than in older groups, indicating an intense period of development in early childhood for the anterior and posterior parts of the CC. Similar results were obtained when 2D callosal area was used for the anterior and posterior parts of the CC. However, divergent results were found in the mid-body and the caudal body of the CC. As shown by differences between 2D estimations and actual 3D measurements of callosal growth, our study highlights the importance of considering the horizontal width in measuring developmental changes in the CC.

Excess of veno-occlusive disease in a randomized clinical trial on a higher trigger for red blood cell transfusion after bone marrow transplantation: a canadian blood and marrow transplant group trial.

Previous studies have shown that maintaining high hemoglobin levels in patients after chemotherapy reduced the length of neutropenia. Thus, we undertook a randomized, controlled, clinical trial in children undergoing allogeneic bone marrow transplantation after receiving a myeloablative conditioning regimen to compare 2 hemoglobin thresholds as triggers for red blood cell transfusion: 120 g/L in the experimental arm and 70 g/L in the control arm. The Data and Safety Monitoring Board closed the study after enrollment of the sixth patient because 3 patients in the experimental arm contracted veno-occlusive disease, but none in the control arm did (P = .05). Ascites was present in all 3 patients, pleura effusion in 2, and portal vein thrombosis in 2. One patient experienced hepatic failure and required treatment with the molecular adsorbent recycling system. Another patient required hemodialysis for renal failure. No major imbalance between groups was seen with regard to risk factors for veno-occlusive disease. Therefore, maintaining the hemoglobin at higher levels should be avoided after hematopoietic stem cell transplantation.

Impact of Sim1 gene dosage on the development of the paraventricular and supraoptic nuclei of the hypothalamus.

The bHLH-PAS transcription SIM1 is required for the development of all neurons of the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus. Mice with a loss of Sim1 die within a few days of birth, presumably because of the lack of a PVN and SON. In contrast, mice with a decrease of Sim1 survive, are hyperphagic and become obese. The mechanism by which Sim1 controls food intake remains unclear. Here we show that the development of specific PVN and SON cell types is sensitive to Sim1 gene dosage. Sim1 haploinsufficiency reduces the number of vasopressin (AVP)- and oxytocin-producing cells in the PVN by about 50 and 80%, respectively, but does not affect the development of Crh, Trh and Ss neurons. A decrease of AVP-producing cells increases the sensitivity of Sim1 heterozygous mice to chronic dehydration. Moreover, retrograde labelling showed a 70% reduction of PVN neurons projecting to the dorsal vagal complex, raising the possibility that a decrease of these axons contributes to the hyperphagia of Sim1(+/-) mice. Sim1 haploinsufficiency is thus associated with a decrease of several PVN/SON cell types, which has the potential of affecting distinct homeostatic processes.

Varicella-zoster virus disease is more frequent after cord blood than after bone marrow transplantation.

Immune reconstitution may differ following cord blood transplantation (CBT) and bone marrow transplantation (BMT), and this may lead to a difference in varicella zoster virus (VZV) disease rates. One hundred fourteen VZV seropositive children received a CBT (37 patients), or a T-replete BMT (77 patients) at our institution. Patients did not received specific VZV disease prophylaxis. VZV disease was diagnosed by immunofluorescence or culture in 41 (36%) patients. In multivariate analysis, VZV disease was more frequent in older children (relative risk [RR] 1.11 per year; 95% confidence interval [CI], 1.04-1.18; P = .002), and after CBT (RR 2.27; 95% CI, 1.18-4.34; P = .013). The cumulative incidence of VZV disease at 3 years posttransplant was 46% following CBT. VZV disease incidence was 71% in CBT patients over 10 years old at transplant. Visceral dissemination occurred in 7 patients (6 CBT and 1 BMT) (P = .005). VZV disease is thus more frequent and more severe after CBT than after BMT.

A survey to describe sleep-facilitating substances used by Canadian emergency physicians.

BACKGROUND: Because night shifts disrupt the normal circadian rhythm, sleep management is crucial for emergency physicians. The purpose of the survey was to describe the use of sleep-facilitating substances (SFSs) by emergency physicians before or after a night shift and to evaluate factors associated with their use. METHODS: All members of the Canadian Association of Emergency Physicians with a Canadian postal address were mailed a copy of the survey. Canadian physicians were eligible if they worked at least one night shift per month and spent 50% or more of their time in emergency medicine. Logistic regression was used to identify characteristics most predictive of using SFSs before or after a night shift. RESULTS: Of the 1621 surveys mailed, 805 were returned completed, for a response rate of 49.6%. Of these, 628 respondents met inclusion criteria and 215 respondents (34%) reported consuming at least one SFS in their career to help them sleep around a night shift. The use of an SFS before a night shift was associated with the use of SFSs after a night shift (odds ratio [OR] 3.8; 95% confidence interval [CI] 2.4-5.9) and the use of SFSs at other times (OR 3.8; 95% CI 2.1-6.6). The use of SFSs after a night shift was associated with the use of a sleep-facilitating technique before a night shift (OR 2.1; 95% CI 1.3-3.3); use of an SFS before a night shift (OR 4.0; 95% CI 2.4-6.4); use of SFSs at other times (OR 4.7; 95% CI 2.6-8.4); and success of a nap before the night shift (OR 0.46; 95% CI 0.25-0.83). CONCLUSION: The rate of SFS use is similar in emergency physicians and other shift workers. Emergency physicians who use SFSs before or after a night shift are more likely to use them at other times as well, and less likely to use them if they nap successfully prior to a night shift.