Guiding principles for pediatric hospitalist programs

Pediatric hospitalist programs have become increasingly popular recently, emulating the growth and success of adult hospitalist programs. This statement provides an overview of hospitalist programs, factors influencing their growth, and their expected benefits. Six guiding principles for the establishment of pediatric hospitalist programs are identified in this statement concerning voluntary referrals; local design; minimum physician-training requirements; arrangement for appropriate follow-up; communication among primary care physicians, subspecialists, and hospitalists; and data collection and outcome measurements.     

Hypoxic-ischemic injury stimulates subventricular zone proliferation and neurogenesis in the neonatal rat

Neurogenesis persists throughout life in the rodent subventricular zone (SVZ) and increases in the adult after brain injury. In this study, postnatal day 7 (P7) rats underwent right carotid artery ligation followed by 8% O2 exposure for 90 min, a lesioning protocol that resulted in ipsilateral forebrain hypoxic-ischemic (HI) injury. The effects of HI injury on SVZ cell proliferation and neurogenesis were examined 1-3 wk later by morphometric measurement of dorsolateral SVZ size; by immunoassays to detect incorporation of bromodeoxyuridine (BrdU) in proliferating cells; and by immunoassays of doublecortin, a microtubule-associated protein expressed only by immature neurons. For determining the cell phenotypes of newly generated cells, tissue sections were double labeled with antibodies to BrdU and markers of mature neurons (neuronal nuclear protein), astrocytes (glial fibrillary acidic protein), or oligodendroglia (RIP). HI injury resulted in enlargement of the ipsilateral SVZ at P14-28 and a corresponding increase in BrdU cell numbers both in the ipsilateral SVZ and striatum at P21. HI injury also stimulated SVZ neurogenesis, based on increased doublecortin immunostaining in the SVZ ipsilateral to lesioning at P14-28. However, 4 wk after HI injury, in the lesioned striatum, although BrdU/glial fibrillary acidic protein and BrdU/RIP-labeled cells were identified, no BrdU/neuronal nuclear protein double-labeled cells were found. These results suggest that although acute neonatal HI injury stimulates SVZ proliferation and neurogenesis, there is inadequate trophic support for survival of newly generated neurons. Identification of the trophic factors that enhance maturation and survival of immature neurons could provide important clues for improving recovery after neonatal brain injury.     

Unifying the spatial population dynamics and molecular evolution of epidemic rabies virus

Infectious disease emergence is under the simultaneous influence of both genetic and ecological factors. Yet, we lack a general framework for linking ecological dynamics of infectious disease with underlying molecular and evolutionary change. As a model, we illustrate the linkage between ecological and evolutionary dynamics in rabies virus during its epidemic expansion into eastern and southern Ontario. We characterized the phylogeographic relationships among 83 isolates of fox rabies virus variant using nucleotide sequences from the glycoprotein-encoding glycoprotein gene. The fox rabies virus variant descended as an irregular wave with two arms invading from northern Ontario into southern Ontario over the 1980s and 1990s. Correlations between genetic and geographic distance suggest an isolation by distance population structure for the virus. The divergence among viral lineages since the most recent common ancestor correlates with position along the advancing wave front with more divergent lineages near the origin of the epidemic. Based on divergence from the most recent common ancestor, the regional population can be partitioned into two subpopulations, each corresponding to an arm of the advancing wave. Subpopulation A (southern Ontario) showed reduced isolation by distance relative to subpopulation B (eastern Ontario). The temporal dynamics of subpopulation A suggests that the subregional viral population may have undergone several smaller waves that reduced isolation by distance. The use of integrated approaches, such as the geographical analysis of sequence variants, coupled with information on spatial dynamics will become indispensable aids in understanding patterns of disease emergence.     

Cortical, thalamic, and hypothalamic responses to cooling and warming the skin in awake humans: a positron-emission tomography study

Thermoregulatory mechanisms are remarkably efficient, ensuring minimal temperature variation within the core of the human body under physiological conditions. Diverse afferent and efferent neural pathways contribute to the monitoring of core and skin temperature, generation of heat, and control of thermal exchange with the external environment. We have investigated the cortical, thalamic, and hypothalamic responses to cooling and warming by using positron-emission tomography activation imaging of subjects clad in a water-perfused suit, which enabled rapid change of their skin-surface temperature. Human brain regions that respond to changes in skin temperature have been identified in the somatosensory cortex, insula, anterior cingulate, thalamus, and hypothalamus, with evidence that the hypothalamic response codes for the direction of temperature change. We conclude that signals from thermosensors in the skin providing crucial afferent information to the brain are integrated with signals from central thermosensors, resulting in thermoregulatory responses that maintain core temperature within a remarkably narrow range.     

Open-label trial of riluzole in generalized anxiety disorder

OBJECTIVE: There is a need to identify novel pharmacotherapies for anxiety disorders. The authors examined the safety and efficacy of riluzole, an antiglutamatergic agent, in adult outpatients with generalized anxiety disorder. METHOD: In an 8-week, open-label, fixed-dose study, 18 medically healthy patients with DSM-IV generalized anxiety disorder received treatment with riluzole (100 mg/day) following a 2-week drug-free period. The primary efficacy measure was the Hamilton Anxiety Rating Scale (HAM-A) score at endpoint. RESULTS: Twelve of the 15 patients who completed the trial responded positively to riluzole. At 8 weeks, eight of the 15 patients had HAM-A score indicating remission of their anxiety. The median time to response was 2.5 weeks. CONCLUSIONS: Riluzole appears to be an effective, well-tolerated, and rapidly acting anxiolytic medication for some patients with generalized anxiety disorder. Larger, placebo-controlled studies are indicated.     

Epilepsy's role in the historical differentiation of religion, magic, and science

A distinction between religion, magic, and science has not always been recognized. Ancient Greek physicians, in their writings about epilepsy, were likely among the first to record the historically important differentiation between religion, magic, and science.