Long-term follow-up of two infants with an implanted cardiac pacemaker

The clinical course of two patients with congenital heart block who had pacemaker implantation at age 7 and 8 months, respectively, is reviewed. One patient at age 10 years has had nine pulse generators Inserted; the other has had six implantations, the most recent a lithium iodine pacemaker, during 81/2 years of observation. Both patients have shown normal physical development and emotional maturation despite multiple hospitalizations and pacemaker replacements, thus demonstrating that electrical pacing, initiated in infancy, can be maintained through childhood without adverse effects.     

Virologic testing in bronchiolitis: does it change management decisions and predict outcomes?

The aim of this study was to evaluate the clinical, therapeutic, laboratory, and radiological differences between respiratory syncytial virus (RSV) and non-RSV bronchiolitis in order to assess if the prior knowledge of viral etiology changed management decisions and would be able to predict outcomes. Medical charts of children <1 year admitted to the emergency department with bronchiolitis during two RSV seasons (2010–2012) were reviewed. We analyzed 221 episodes of bronchiolitis. The percentage of exams performed (95 % confidence interval (CI) 0.74–2.52), abnormal laboratory and radiological findings (95 % CI 0.53–16.89) did not differ between groups. RSV bronchiolitis had a more severe clinical course. However, virologic testing for RSV had low specificity in identifying at-risk patients for hospitalization, longer hospital length of stay, and need of oxygen therapy and nasogastric tube (44, 40, 42, and 35 %, respectively), and while statistically significant, the positive likelihood ratios were only slightly greater than 1. Conclusion: Although RSV bronchiolitis has a more severe clinical course, virologic testing does not help in management decisions, and at an individual level, as a performance test, it seems insufficient to precisely predict outcomes.     

Quantitative analysis of proliferation and cell cycle length during development of the rat retina

The rat retina has been a useful model system for the study of the development of the central nervous system (CNS). In order to facilitate future studies on the mechanisms that control retinal growth, we have quantified the proliferation of retinal cells and the length of the cell cycle throughout development. For each day during development, the number of mitotic and postmitotic cells per retina, the proportion of cycling cells, S phase length, and cell cycle length were determined through quantification of cell numbers and ³H-thymidine labeling. As retinal development proceeds, the proportion of cycling cells decreases, and cell cycle length increases, in part due to an increase in S phase length. © 1996 Wiley-Liss, Inc.     

A technique for detecting GABA in the human brain with PRESS localization and optimized refocusing spectral editing radiofrequency pulses

A proton magnetic resonance spectral editing technique is presented that uses PRESS excitation to achieve spatially localized measurements of brain gamma-aminobutyric acid (GABA). The homonuclear difference spectroscopy technique employs a frequency selective inversion pulse to suppress the creatine resonance at 3.0 ppm. The timing of this pulse is optimized to maximize the suppression of creatine by minimizing the effect of the editing pulse on the 3.0 ppm resonances. The PRESS excitation achieves three dimensional spatial localization in a single acquisition making it less sensitive to patient motion than multiple acquisition techniques. The performance and utility of this technique were evaluated by phantom experiments and by in vivo measurements of brain GABA concentration in 10 normal subjects.