Evaluation of the effects of sensory denervation on osteoblasts by 3 H-proline autoradiography

The inferior alveolar nerve was unilaterally resected in 30-day-old mice; other animals were unilaterally sham-operated. At 15, 30, 60, 90, or 150 days after surgery, the mice were injected with 2μCi of 3 H-proline (sp. act. 1.0 Ci/mM) per g of body weight and killed 15, 30, or 60 min later. Autoradiographs were prepared from 5μm decalcified sagittal sections of mandibles and grain counts made over periosteal osteoblasts mesial to the first molar. In denervated mandibles, osteoblasts incorporated less isotope compared to controls with differences being maximal at the early intervals. These differences became attenuated with time, possibly due to an intrinsic compensatory mechanism, secondary to neurotrophic regulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47675/1/441_2004_Article_BF00219365.pd

Supernova remnants: the X-ray perspective

Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects.And in particular the advances made in X-ray imaging spectroscopy over the last two decades has greatly increased our knowledge about supernova remnants. It has made it possible to map the products of fresh nucleosynthesis, and resulted in the identification of regions near shock fronts that emit X-ray synchrotron radiation. In this text all the relevant aspects of X-ray emission from supernova remnants are reviewed and put into the context of supernova explosion properties and the physics and evolution of supernova remnants. The first half of this review has a more tutorial style and discusses the basics of supernova remnant physics and thermal and non-thermal X-ray emission. The second half offers a review of the recent advances.The topics addressed there are core collapse and thermonuclear supernova remnants, SN 1987A, mature supernova remnants, mixed-morphology remnants, including a discussion of the recent finding of overionization in some of them, and finally X-ray synchrotron radiation and its consequences for particle acceleration and magnetic fields.Comment: Published in Astronomy and Astrophysics Reviews. This version has 2 column-layout. 78 pages, 42 figures. This replaced version has some minor language edits and several references have been correcte

Neutral hydrogen compact absorption features in Cassiopeia A

Very Large Array (VLA) observations of the lambda 21 cm HI line towards Cassiopeia A (Gas A) have been performed. The velocity interval observed was from -38 to -362 (LSR) km s(-1), with a resolution of 2.6 km s(-1) and a beam size of 14.2'' x 11.4'' Opacity images show the presence of a number of small absorption HI features in the velocity interval -62 to -69 km s(-1) (LSR) which, on the basis of several arguments, are postulated to be physically associated with Cas A. These cold HI knots have sizes of <0.1pc and show spatial substructure. Their velocities lie well outside the range of the intervening HI in the Perseus spiral arm, i.e. 0 to -55 km s(-1). We demonstrate that the HI knots cannot be described as shocked interstellar cloudlets engulfed by the blast wave of the supernova remnant (SNR). Instead, we propose that these low velocity HI features are recombined wind driven clumps moving ahead of the supernova (SN) shock front. This hypothesis is supported by the ages derived for the knots, varying from 8 x 10(3) to 5 x 10(4) years, which implies that these features were originally accelerated during the Wolf-Rayet (WR) phase of the precursor star

Impaired mitochondrial energy metabolism as a novel risk factor for selective onset and progression of dementia in oldest-old subjects

Wei Zhao,1,2 Jun Wang,1,2 Merina Varghese,1 Lap Ho,1,2 Paolo Mazzola,1,3 Vahram Haroutunian,2,4,5 Pavel L Katsel,2,4 Gary E Gibson,6 Samara Levine,1 Lauren Dubner,1 Giulio Maria Pasinetti1,2,4,7 1Department of Neurology,&nbsp;Icahn School of Medicine at Mount Sinai, New York, NY, USA; 2Geriatric Research Education Clinical Center &ndash; James J Peter VA Medical Center, Bronx, NY, USA; 3Department of&nbsp;Health Sciences, University of Milano-Bicocca, Monza, Italy; 4Department of Psychiatry, 5Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; 6Department of Neurology and Neuroscience, Weill Cornell Medical College, Burke Medical Research Institute, New York, NY, USA; 7Department of Geriatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA Abstract: Recent evidence shows that Alzheimer disease (AD) dementia in the oldest-old subjects was associated with significantly less amyloid plaque and fibrillary tangle neuropathology than in the young-old population. In this study, using quantitative (q) PCR studies, we validated genome-wide microarray RNA studies previously conducted by our research group. We found selective downregulation of mitochondrial energy metabolism genes in the brains of oldest-old, but not young-old, AD dementia cases, despite a significant lack of classic AD neuropathology features. We report a significant decrease of genes associated with mitochondrial pyruvate metabolism, the tricarboxylic acid cycle (TCA), and glycolytic pathways. Moreover, significantly higher levels of nitrotyrosylated (3-NT)-proteins and 4-hydroxy-2-nonenal (HNE) adducts, which are indexes of cellular protein oxidation and lipid peroxidation, respectively, were detected in the brains of oldest-old subjects at high risk of developing AD, possibly suggesting compensatory mechanisms. These findings support the hypothesis that although oldest-old AD subjects, characterized by significantly lower AD neuropathology than young-old AD subjects, have brain mitochondrial metabolism impairment, which we hypothesize may selectively contribute to the development of dementia. Outcomes from this study provide novel insights into the molecular mechanisms underlying clinical dementia in young-old and oldest-old AD subjects and provide novel strategies for AD prevention and treatment in oldest-old dementia cases. Keywords: Alzheimer disease, energy metabolism, neuropathology, mitochondria, dementi

Trauma exposure and PTSD among older adolescents in foster care

PURPOSE: Youth in foster care represent a highly traumatized population. However, trauma research on this population has focused primarily on maltreatment rather than the full spectrum of trauma experiences identified within the DSM-IV. The current study aims to fill this gap by reporting the prevalence of exposure to specific types of traumatic events for a large sample of youth with foster care experience. The study also reports the likelihood of lifetime PTSD diagnoses associated with each specific type of trauma. METHOD: Data are from a longitudinal panel study of 732 adolescents aged 17 and 18 who were in foster care. Lifetime trauma exposure and PTSD diagnosis were assessed using the Composite International Diagnostic Interview. Statistical comparisons were made using logistic regressions. RESULTS: The majority of respondents had experienced at least one trauma in their lifetime. While overall trauma prevalence did not differ by gender, males were more likely to experience Interpersonal Violence and Environmental Trauma, while females were more likely to experience Sexual Trauma. Caucasian participants reported higher rates of trauma exposure than African-American participants. The types of trauma associated with the highest probability of a lifetime PTSD diagnosis were rape, being tortured or a victim of terrorists, and molestation. CONCLUSIONS: Youth in foster care are a highly traumatized population and meet diagnostic criteria for PTSD at higher rates than general youth populations. The ongoing impact of trauma may be particularly problematic for these young people given their abrupt transition to independence