Pax6 Controls Astrocyte Positional Identity in the Spinal Cord

Astrocytes constitute the most abundant cell type in the CNS, and play diverse functional roles, but the ontogenetic origins of this phenotypic diversity are poorly understood. We have investigated whether positional identity, a fundamental organizing principle governing the generation of neuronal subtype diversity, is also relevant to astrocyte diversification. We identified three positionally distinct subtypes of white matter astrocytes in the spinal cord, which can be distinguished by the combinatorial expression of Reelin and Slit1. These astrocyte subtypes derive from progenitor domains expressing the homeodomain transcription factors Pax6 and Nkx6.1, respectively. Loss- and gain-of-function experiments indicate that the positional identity of these astrocyte subtypes is controlled by Pax6 and Nkx6.1, in a combinatorial manner. Thus, positional identity is an organizing principle underlying astrocyte, as well as neuronal, subtype diversification, and is controlled by a homeodomain transcriptional code whose elements are re-utilized following the specification of neuronal identity earlier in development

Modification of classical electron transport due to collisions between electrons and fast ions

A Fokker-Planck model for the interaction of fast ions with the thermal electrons in a quasi-neutral plasma is developed. When the fast ion population has a net flux (i.e. the distribution of the fast ions is anisotropic in velocity space) the electron distribution function is significantly perturbed from Maxwellian by collisions with the fast ions, even if the fast ion density is orders of magnitude smaller than the electron density. The Fokker-Planck model is used to derive classical electron transport equations (a generalized Ohm's law and a heat flow equation) that include the effects of the electron-fast ion collisions. It is found that these collisions result in a current term in the transport equations which can be significant even when total current is zero. The new transport equations are analyzed in the context of a number of scenarios including $\alpha$ particle heating in ICF and MIF plasmas and ion beam heating of dense plasmas

Identification of Positionally Distinct Astrocyte Subtypes whose Identities Are Specified by a Homeodomain Code

Astrocytes constitute the most abundant cell type in the central nervous system (CNS) and play diverse functional roles, but the ontogenetic origins of this phenotypic diversity are poorly understood. We have investigated whether positional identity, a fundamental organizing principle governing the generation of neuronal subtype diversity, is also relevant to astrocyte diversification. We identified three positionally distinct subtypes of white-matter astrocytes (WMA) in the spinal cord, which can be distinguished by the combinatorial expression of Reelin and Slit1. These astrocyte subtypes derive from progenitor domains expressing the homeodomain transcription factors Pax6 and Nkx6.1, respectively. Loss- and gain-of-function experiments indicate that the positional identity of these astrocyte subtypes is controlled by Pax6 and Nkx6.1 in a combinatorial manner. Thus, positional identity is an organizing principle underlying astrocyte, as well as neuronal, subtype diversification and is controlled by a homeodomain transcriptional code whose elements are reutilized following the specification of neuronal identity earlier in development

The Faces of Kahn

[EN] The self-portraits produced by Louis Kahn are capable of revealing more aspects of his person than the majority of the photographs taken of him throughout his existence (1901-1974). Consciously or unconsciously, perhaps involuntarily, Kahn leads us through them into the folds of his personality. Although developed in hardly twenty years, they enclose an entire lifetime. The six self-portraits that are presented here correspond to the period between the years 1928 and 1949.[ES] Los seis autorretratos realizados por Louis Kahn entre1928 y 1949 son capaces de desvelar más aspectos de la persona que el conjuntode la gran mayoría de las fotografías tomadas sobre él a lo largo de su existencia(1901-1974). Consciente o inconscientemente, tal vez involuntariamente Kahn nosconduce a través de ellos hacia pliegues de su personalidad que, aunquedesvelados en apenas veinte años, encierran toda una vidaMaestre Galindo, CE. (2014). Las caras de Kahn. EGA. Revista de Expresión Gráfica Arquitectónica. 19(24):116-125. doi:10.4995/ega.2014.1781.SWORD1161251924Berger, J., 1969. The Changing View of Man in the Portrait. Selected Essays and Article. The Look of Things. Harmondsworth. Penguin Books, 1972.Berger, J., 1980. Francis Bacon and Walt Disney. About Looking. Londres, Writers and Readers Publishing Cooperative.Brownlee, D.B., De Long, D.G., 1991. Adventures of Unexplored Place. In the Realm of Architecture. Kahn. New York. Rizzoli.Hochstim, J., 1991. The paintings and sketchings of Louis I. Kahn. New York. Rizzoli.Tyng, A.G., 1997. Professional and Private Lives. The Rome Letters 1953- 1954. Louis Kahn to Anne Tyng. New York, Rizzoli

Stability of racemic and chiral steady states in open and closed chemical systems

The stability properties of models of spontaneous mirror symmetry breaking in chemistry are characterized algebraically. The models considered here all derive either from the Frank model or from autocatalysis with limited enantioselectivity. Emphasis is given to identifying the critical parameter controlling the chiral symmetry breaking transition from racemic to chiral steady-state solutions. This parameter is identified in each case, and the constraints on the chemical rate constants determined from dynamic stability are derived.Comment: 25 pages, 1 figure. To appear in Physics Letters A (2008

Effects of local hypothermia-rewarming on physiology, metabolism and inflammation of acutely injured human spinal cord.

In five patients with acute, severe thoracic traumatic spinal cord injuries (TSCIs), American spinal injuries association Impairment Scale (AIS) grades A-C, we induced cord hypothermia (33 °C) then rewarming (37 °C). A pressure probe and a microdialysis catheter were placed intradurally at the injury site to monitor intraspinal pressure (ISP), spinal cord perfusion pressure (SCPP), tissue metabolism and inflammation. Cord hypothermia-rewarming, applied to awake patients, did not cause discomfort or neurological deterioration. Cooling did not affect cord physiology (ISP, SCPP), but markedly altered cord metabolism (increased glucose, lactate, lactate/pyruvate ratio (LPR), glutamate; decreased glycerol) and markedly reduced cord inflammation (reduced IL1β, IL8, MCP, MIP1α, MIP1β). Compared with pre-cooling baseline, rewarming was associated with significantly worse cord physiology (increased ICP, decreased SCPP), cord metabolism (increased lactate, LPR; decreased glucose, glycerol) and cord inflammation (increased IL1β, IL8, IL4, IL10, MCP, MIP1α). The study was terminated because three patients developed delayed wound infections. At 18-months, two patients improved and three stayed the same. We conclude that, after TSCI, hypothermia is potentially beneficial by reducing cord inflammation, though after rewarming these benefits are lost due to increases in cord swelling, ischemia and inflammation. We thus urge caution when using hypothermia-rewarming therapeutically in TSCI

The Transcription Factor NFIA Controls the Onset of Gliogenesis in the Developing Spinal Cord

The mechanisms controlling the transition from neurogenesis to gliogenesis in the vertebrate CNS are incompletely understood. We identified a family of transcription factors, called NFI genes, which are induced throughout the spinal cord ventricular zone (VZ) concomitantly with the induction of GLAST, an early marker of gliogenesis. NFIA is both necessary and sufficient for GLAST induction in the VZ. Unexpectedly, NFIA is also essential for the continued inhibition of neurogenesis in VZ progenitors. This function is mediated by the requirement of NFIA for the expression of HES5, a Notch effector. However, Notch effectors are unable to promote glial-fate specification in the absence of NFIA. Thus, NFIA links the abrogation of neurogenesis to a generic program of gliogenesis, in both astrocyte and oligodendrocyte VZ progenitors. At later stages, NFIA promotes migration and differentiation of astrocyte precursors, a function that is antagonized in oligodendrocyte precursors by Olig2

Telephone and face to face methods of assessment of veteran's community reintegration yield equivalent results

<p>Abstract</p> <p>Background</p> <p>The Community Reintegration of Service Members (CRIS) is a new measure of community reintegration developed to measure veteran's participation in life roles. It consists of three sub-scales: Extent of Participation (Extent), Perceived Limitations with Participation (Perceived), and Satisfaction with Participation (Satisfaction). Testing of the CRIS measure to date has utilized in-person administration. Administration of the CRIS measure by telephone, if equivalent to in-person administration, would be desirable to lower cost and decrease administrative burden. The purpose of this study was to test the equivalence of telephone and in-person mode of CRIS administration.</p> <p>Methods</p> <p>A convenience sample of 102 subjects (76% male, 24% female, age mean = 49 years, standard deviation = 8.3) were randomly assigned to received either telephone interview at Visit 1 and in-person interview at Visit 2, or in-person interview at Visit 1 and telephone interview a Visit 2. Both Visits were conducted within one week. Intraclass correlation coefficients, ICC (2,1), were used to evaluate correspondence between modes for both item scores and summary scores. ANOVAs with mode order as a covariate were used to test for presence of an ordering effect.</p> <p>Results</p> <p>ICCs (95%CI) for the subscales were 0.92 (0.88-0.94) for Extent, 0.85 (0.80-0.90) for Perceived, and 0.89 (0.84-0.93) for Satisfaction. No ordering effect was observed.</p> <p>Conclusion</p> <p>Telephone administration of the CRIS measure yielded equivalent results to in-person administration. Telephone administration of the CRIS may enable lower costs of administration and greater adoption.</p

Organic Geochemical Studies. I. Molecular Criteria for Hydrocarbon Genesis

In recent years the search for life-forms at the earliest periods of geological time has been continued not only at the morphological level but also at the molecular level. This has been possible as a result of the increase in the biochemical knowledge and with the advent of analytical techniques that are capable of describing the intimate molecular architecture of individual molecules in acute detail. The fundamental premises upon which this organic geochemical approach rest are the following: that certain molecules, possessing a characteristic structural skeleton, show a reasonable stability to degradation over long periods of geological time; that their structural specificity can be understood in terms of known biosynthetic sequences; and that their formation by any non-biological means is of negligible probability. In this manuscript it is proposed to critically re-examine these premises and to establish criteria whereby one can differentiate molecules derived from biological systems from those that have their origin in non-biological processes. The importance of establishing such criteria lies in the significance these criteria have in determining whether life exists, or has existed, on other planets. Within the very near future it may be possible to provide an initial answer to this question when the first lunar samples are returned to the earth for analysis

Life Course Socioeconomic Position and Incidence of Diabetes Mellitus Among Blacks and Whites: The Alameda County Study, 1965-1999

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65009/1/Kaplan_Life Course Socioeconomic Position and Incidence of Diabetes_2009.pd