RESUMO
Retinal ganglion cell axons forming the optic nerve (ON) emerge unmyelinated from the eye and become myelinated after passage through the optic nerve lamina region (ONLR), a transitional area containing a vascular plexus. The ONLR has a number of unusual characteristics: it inhibits intraocular myelination, enables postnatal ON myelination of growing axons, modulates the fluid pressure differences between eye and brain, and is the primary lesion site in the age-related disease open angle glaucoma (OAG). We demonstrate that the human and rodent ONLR possesses a mitotically active, age-depletable neural progenitor cell (NPC) niche, with unique characteristics and culture requirements. These NPCs generate both forms of macroglia: astrocytes and oligodendrocytes, and can form neurospheres in culture. Using reporter mice with SOX2-driven, inducible gene expression, we show that ONLR-NPCs generate macroglial cells for the anterior ON. Early ONLR-NPC loss results in regional dysfunction and hypomyelination. In adulthood, ONLR-NPCs may enable glial replacement and remyelination. ONLR-NPC depletion may help explain why ON diseases such as OAG progress in severity during aging.
Assuntos
Neurônios/citologia , Nervo Óptico/citologia , Nicho de Células-Tronco , Células-Tronco/citologia , Animais , Astrócitos , Axônios/metabolismo , Diferenciação Celular , Glaucoma de Ângulo Aberto/genética , Glaucoma de Ângulo Aberto/metabolismo , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos , Camundongos , Bainha de Mielina/metabolismo , Neuroglia , Neurônios/metabolismo , Oligodendroglia , Nervo Óptico/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Células-Tronco/metabolismoRESUMO
OBJECTIVES: No studies have investigated gross motor skill (GMS) proficiency of preschool-aged children across different income settings in South Africa. Research from high-income countries suggests that children from low-income settings display poorer GMS proficiency compared to higher-income peers. This study aimed to (1) describe GMS proficiency of preschool-aged children in urban high-income (UH), urban low-income (UL) and rural low-income (RL) settings; and (2) explore differences in proficiency between income settings and sex. DESIGN: Descriptive cross-sectional study. METHODS: The Test of Gross Motor Development-Edition 2 (TGMD-2) was used to assess GMS. The TGMD-2 gross motor quotient, standardised scores and raw scores were used to describe proficiency. RESULTS: GMS proficiency was assessed in n=259 3-6-year-old children (n=46 UH, n=91 UL, n=122 RL). Overall, 93% of the children were classified as having 'average' or better GMS. According to TGMD-2 standardised scores, the RL children performed significantly better than UH and UL children (p=0.028 and p=0.009, respectively). RL children were significantly more proficient than UH and UL children in the strike and horizontal jump when comparing raw scores. Overall, boys performed significantly better than girls in the strike, stationary dribble, kick and leap when comparing raw scores (all p<0.001). CONCLUSIONS: This study reports high GMS proficiency in preschool-aged children across income settings in South Africa. The factors associated with higher GMS in low-income settings are not immediately obvious. Thus, future research should explore potential factors and identify opportunities to ensure that GMS proficiency is capitalised on as preschool-aged children enter formal schooling.
Assuntos
Destreza Motora , Pré-Escolar , Estudos Transversais , Teste de Esforço , Feminino , Humanos , Renda , Masculino , População Rural , Fatores Sexuais , África do Sul , População UrbanaRESUMO
BACKGROUND: The Saccharomyces cerevisiae protein Cks1 (cyclin-dependent kinase subunit 1) is essential for cell-cycle progression. The biological function of Cks1 can be modulated by a switch between two distinct molecular assemblies: the single domain fold, which results from the closing of a beta-hinge motif, and the intersubunit beta-strand interchanged dimer, which arises from the opening of the beta-hinge motif. The crystal structure of a cyclin-dependent kinase (Cdk) in complex with the human Cks homolog CksHs1 single-domain fold revealed the importance of conserved hydrophobic residues and charged residues within the beta-hinge motif. RESULTS: The 3.0 A resolution Cks1 structure reveals the strict structural conservation of the Cks alpha/beta-core fold and the beta-hinge motif. The beta hinge identified in the Cks1 structure includes a novel pivot and exposes a cluster of conserved tyrosine residues that are involved in Cdk binding but are sequestered in the beta-interchanged Cks homolog suc1 dimer structure. This Cks1 structure confirms the conservation of the Cks anion-binding site, which interacts with sidechain residues from the C-terminal alpha helix of another subunit in the crystal. CONCLUSIONS: The Cks1 structure exemplifies the conservation of the beta-interchanged dimer and the anion-binding site in evolutionarily distant yeast and human Cks homologs. Mutational analyses including in vivo rescue of CKS1 disruption support the dual functional roles of the beta-hinge residue Glu94, which participates in Cdk binding, and of the anion-binding pocket that is located 22 A away and on an opposite face to Glu94. The Cks1 structure suggests a biological role for the beta-interchanged dimer and the anion-binding site in targeting Cdks to specific phosphoproteins during cell-cycle progression.
Assuntos
Proteínas de Ciclo Celular , Proteínas Fúngicas/química , Conformação Proteica , Proteínas de Saccharomyces cerevisiae , Proteínas Adaptadoras de Transdução de Sinal , Sequência de Aminoácidos , Ânions/metabolismo , Ciclo Celular , Análise Mutacional de DNA , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Humanos , Dados de Sequência Molecular , Ligação Proteica , Saccharomyces cerevisiaeRESUMO
PurposeAlthough the length of the average human adult optic nerve (ON) is known, the average length of the normal full-term, newborn ON has never been adequately evaluated, nor has the in vivo growth rate of the human ON been determined. We wanted to identify both the average length of the newborn human ON and its rate of anteroposterior growth.Patients and methodsUsing MRIs from a newly generated set of normal newborn infants rescanned at 1 year, and from different aged groups, we calculated average newborn ON length and growth rate.ResultsThe newborn human ON is 25.3±0.3 mm in length from globe to chiasm, and grows by 80% in length after birth, with maximum speed of elongation occurring in the first 3 years of life, attaining full length by 15 years of age.ConclusionThe human ON grows dramatically in the first 3 years of life, and continues to grow for the first two decades. These data are relevant for pediatric treatments that may impede or alter orbital growth in infants, and maximal susceptibility to oncological procedures in early childhood.
Assuntos
Nervo Óptico/crescimento & desenvolvimento , Adolescente , Envelhecimento/fisiologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Imageamento por Ressonância Magnética , Masculino , Bainha de Mielina/fisiologia , Nervo Óptico/anatomia & histologia , Nervo Óptico/diagnóstico por imagem , Valores de Referência , Nascimento a Termo , Adulto JovemRESUMO
A mutation directing an amino acid substitution in the conserved beta-hinge region of one of the human Cks isoforms, CksHs2, was constructed by site-directed mutagenesis. Replacement of glutamine for glutamate 63 (E63Q) was predicted to stabilize the beta-interchanged dimeric and hexameric assembly of CksHs2. However, such an effect was seen only at high, non-physiological pH. Three-dimensional structures of the E63Q hexameric mutant protein were determined to 2.6 A resolution in a P4(3)2(1)2 space group and 2.1 A in the C2 space group isostructural with wild-type, and both were shown to be virtually identical to the refined 1.7 A wild-type structure. Thus, the E63Q mutation did not alter the wild-type structure and assembly of CksHs2 but, surprisingly, disrupted the essential biological function of the protein and significantly reduced its ability to bind to cyclin-dependent kinases. The Kd of wild-type CksHs2 for CDK2 was 5.05 x 10(-8) M, whereas the affinity of the mutant protein for CDK2 was too low to allow a determination. These data, coupled with the observation that monomeric but not hexameric CksHs2 interacts with cyclin-dependent kinases, suggest that glutamine 63 is likely to be directly involved in cyclin-dependent kinase binding in vitro and in vivo.
Assuntos
Quinases relacionadas a CDC2 e CDC28 , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular , Quinases Ciclina-Dependentes/metabolismo , Proteínas Quinases , Sequência de Bases , Sítios de Ligação , Proteína Quinase CDC2/metabolismo , Proteínas de Transporte/genética , Sequência Conservada , Quinase 2 Dependente de Ciclina , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Conformação Proteica , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismoRESUMO
We have fine mapped 29 ESTs of Genemap'99 to YACs and radiation hybrids covering 8 cM of the chromosomal region of 3q28-q29. Focusing on the genetic interval of approximately 1 Mb between markers D3S3669 and D3S3562 we established a sequence-ready PAC contig which covers the OPA1 locus containing the gene causing autosomal dominant optic atrophy (ADOA; OMIM*165500). The fidelity of the contig was increased by the generation of 181 PAC end sequences, 84 of which resulted in PCR-able STSs. Sequence content evaluation of the PAC ends by BLAST analysis identified two novel ESTs localising to the OPA1 crucial interval.
Assuntos
Cromossomos Humanos Par 3 , Atrofias Ópticas Hereditárias/genética , Mapeamento Cromossômico , Cromossomos Artificiais de Levedura , Clonagem Molecular , Mapeamento de Sequências Contíguas , Etiquetas de Sequências Expressas , HumanosRESUMO
PURPOSE: Two cell lines derived from ocular tumors of a transgenic mouse expressing the SV40 large T antigen have been established as models of human retinoblastoma. One line, TM, originated from a metastasis, and the other, TE, originated from the primary tumor. The authors compared these two lines with the normal adult mouse eye by analysis of the expression of five photoreceptor cell-specific proteins: IRBP, opsin, rod- and cone-specific transducins, and S-antigen. The authors sought to determine which of these proteins was expressed qualitatively and to examine semi-quantitatively for changes in the levels of expression in the cell lines. METHOD: Western blot analysis was used to detect photoreceptor-specific intracellular or secreted proteins. Total RNA was prepared from cultured cells or from mouse adult whole eye. Specific messenger levels in total RNA were determined either by northern hybridization analysis or by a semi-quantitative polymerase chain reaction (PCR), coupled to complementary DNA (cDNA) substrates prepared from total RNA. RESULTS: IRBP was present in the retinoblastoma cell lines and secreted into the medium. Neither S-antigen nor opsin were detectable by immunoblotting. IRBP and cone transducin mRNA were present in both cell lines. In contrast, opsin, rod transducin, and S-Antigen mRNAs were not detectable by PCR. beta-actin was present in the mRNA populations of whole eye and retinoblastoma. SV40 large T antigen mRNA was present only in retinoblastoma cells. CONCLUSIONS: IRBP and cone transducin expression in mouse retinoblastoma cells is independent of signaling provided directly or indirectly through large T antigen or Rb105 regulatory cascades. The pattern of photoreceptor-specific gene expression is similar to that seen in human retinoblastoma cell lines. These murine-derived cell lines may be useful as a tool to study IRBP and cone transducin expression in vitro and to determine early retinoblast expression patterns in the mouse.
Assuntos
Neoplasias Oculares/metabolismo , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Células Fotorreceptoras/metabolismo , Retinoblastoma/metabolismo , Animais , Sequência de Bases , Northern Blotting , Western Blotting , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Humanos , Camundongos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Mensageiro/metabolismo , Células Tumorais CultivadasRESUMO
PURPOSE: Despite documented age-related changes in retinal function and histology, little is known about the pattern of gene expression during normal aging of the vertebrate retina. This study was undertaken to definitively characterize gene expression in the primate retina during aging. METHODS: Human retina cDNA library clones were arrayed at high density on nylon membranes and screened with mixed cDNA probes generated from young (4-year-old) and old (80-year-old) human retinae. Clones showing a more than twofold difference in intensity were rescreened by dot blot analysis with the same probes and with mixed cDNA probes generated from young (2-3 years) and old (27-35 years) rhesus monkeys. One clone identified by its differential (age-putative) signal, and age-related differential expression was used for analysis of Northern blot analysis of total retinal RNA from human donors (35 weeks to 94 years of age) and two rhesus monkeys (2 and 27 years of age). The identified clone was sequenced and compared with entries in the GenBank/EMBL databases. Western blot analysis was performed on protein isolated from the retina of human donors aged 4 to 64 years and rhesus monkeys aged 18 months and 35 years. RESULTS: Approximately 1.6% of the 55,368 retina-expressed sequences examined show age-related changes between tissues from young and old donors. The mRNA level one clone, identical with heat shock cognate (HSC)70, was altered during normal retinal aging in primates. Regression analysis of Northern blot analysis signals from 23 human donors suggested that there may be a two- to threefold decrease in HSC70 mRNA levels in the human retina by the eighth decade of life. Western blot analysis also showed lower levels of the 70-kDa HSC protein in older tissues of both primates. CONCLUSIONS: HSC70 mRNA levels apparently decline during normal aging of the primate retina. Because the heat shock 70 protein family may play important roles in ocular development and protection from various biologic and environmental stresses, decreased HSC70 levels in the retina during aging may contribute to the apparent increased susceptibility of the retina to age-acquired retinal disease.
Assuntos
Envelhecimento/fisiologia , Proteínas de Transporte/genética , Expressão Gênica , Proteínas de Choque Térmico HSP70/genética , RNA Mensageiro/biossíntese , Retina/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Northern Blotting , Western Blotting , Proteínas de Transporte/biossíntese , Criança , Pré-Escolar , Sondas de DNA/química , Proteínas de Choque Térmico HSC70 , Proteínas de Choque Térmico HSP70/biossíntese , Humanos , Lactente , Macaca mulatta , Pessoa de Meia-IdadeRESUMO
PURPOSE: Although specific genes play a role in regional retinal disease, the correlation of regional gene expression in the disease-affected site has not been previously ascertained. Non-human primates are widely used in models of human retinal function and are theorized to have identical (to human) patterns of expression, but no correlation between primate and human regional retinal gene expression has ever been performed. We wanted to evaluate the pattern of regional gene expression for a number of genes whose dysfunctions are known to selectively affect specific regions of the human retina, and to determine whether patterns of regional gene expression in nonhuman primates correlate with the human. METHODS: Human and rhesus monkey eyes were dissected into retina, retinal pigment epithelium (RPE)/choroid and isolated RPE. Retinal regions were dissected, total RNA was isolated and northern analysis performed. Complementary DNA (cDNA) probes were prepared from genes associated with regional retinal disease. These genes are: rod opsin, the alpha-subunit of rod phosphodiesterase, RDS-peripherin, rod outer membrane (ROM) protein, ornithine aminotransferase (OAT), choroideremia gene product (CHM), tissue specific inhibitor of metalloproteinases-3 (TIMP-3), and red/green photoreceptor pigment protein. We also compared expression of Norrie disease product (NDP), a gene whose mutation is known to globally affect the retina. RESULTS: Rod-specific mRNA expression is highest in the retinal midperiphery, and cone-specific mRNA levels were highest in total RNA from the cone-dominant fovea. mRNA levels for genes coding for proteins expressed in both rod- and cone photoreceptors (RDS-peripherin and ROM-1) are also highest in total RNA from the retinal midperiphery. Regional mRNA levels of CHM and OAT do not directly correlate with their patterns of disease expression. NDP mRNA expression was equivalent in both fovea and midperipheral retina total RNA. Patterns of gene expression were qualitatively similar for both human and rhesus monkey retina. CONCLUSIONS: Regional retinal gene expression is an important factor in regional disease. However, for genes not solely expressed by a single photoreceptor subtype, other factors, such as regional metabolic differences, intra- and intercellular interactions, are also likely to be important in predisposing a single retinal region to disease. The pattern of neural retina OAT mRNA expression may have important implications in determining the appropriate tissue approach in gene therapy for gyrate atrophy. Regional retinal gene expression likely plays a significant, but nonexclusive role in the development of regional retinal disease.
Assuntos
Alquil e Aril Transferases , Expressão Gênica , Glicoproteínas de Membrana , Retina/metabolismo , Degeneração Retiniana/metabolismo , Proteínas rab de Ligação ao GTP , 3',5'-GMP Cíclico Fosfodiesterases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Northern Blotting , Proteínas de Transporte/metabolismo , Criança , Corioide/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6 , Proteínas do Olho/metabolismo , Fóvea Central/metabolismo , Humanos , Proteínas de Filamentos Intermediários/metabolismo , Macaca mulatta , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/metabolismo , Ornitina-Oxo-Ácido Transaminase/metabolismo , Periferinas , Epitélio Pigmentado Ocular/metabolismo , RNA Mensageiro/metabolismo , Degeneração Retiniana/genética , Pigmentos da Retina/metabolismo , Opsinas de Bastonetes/metabolismo , Tetraspaninas , Inibidor Tecidual de Metaloproteinase-3/metabolismoRESUMO
PURPOSE: In humans, the fovea is the region of the retina responsible for acute vision. Disorders affecting the fovea are responsible for the majority of cases of untreated blindness in the developed world, yet are poorly understood at the molecular level. Our goal is to identify genes that are preferentially expressed within the human fovea as compared to the midperipheral retina (differential fovea clones). MATERIALS AND METHODS: An unamplified fovea cDNA library was differentially screened with cDNA probes derived from either human fovea or midperipheral retina. Rounds of secondary screening and northern analysis were used to verify the expression pattern of a selective number of clones isolated. RESULTS: Forty-one differential fovea clones were isolated from a screening of 10,000 phage clones (clones). Of these clones, 31.5 % correspond to known sequences present in GenBank/EMBL and 70.7% represent novel human fovea expressed sequence tags (ESTs). Northern analysis of selected clones demonstrated that they represent genes expressed at higher levels in the human fovea than in the midperipheral retina. CONCLUSIONS: Genes that are more highly expressed in the fovea as opposed to the midperipheral retina are likely to represent essential genes for fovea function. Using our fovea cDNA library, we are able to isolate differential human fovea clones at an incidence of 41/10,000 clones screened. We demonstrate that there is a high level of differential gene expression within different regions of the human retina.
Assuntos
Fóvea Central/química , Regulação da Expressão Gênica , Genes/genética , Adolescente , Adulto , Idoso , Northern Blotting , Criança , Pré-Escolar , Clonagem Molecular/métodos , Biblioteca Gênica , Humanos , Pessoa de Meia-Idade , Mitocôndrias/química , Retina/químicaRESUMO
PURPOSE: The clusterin gene encodes a multi-functional protein that has been identified in different tissues, including a number of different eye tissues, primarily in the mouse and to a much lesser extent in humans. Clusterin has been implicated in a number of cellular processes such as lipid transport, membrane integrity, apoptosis, and neurodegeneration, all of which could be important to the biology of the eye. In the current communication, we provide data that confirms the expression of clusterin in a number of different human eye tissues and establishes the expression profile of this gene in monkey derived eye tissues. The issue that we sought to examine is whether a broad profile of clusterin expression in the eye is consistent in primates (monkey and human). METHODS: The majority of our study was done using monkey eye tissues. Where possible, we have used human tissues in order to confirm published findings. Northern and western analysis was performed using tissues derived from monkey eyes. In situ hybridization and immunochemistry were carried out on human eye sections. RESULTS: Clusterin mRNA is expressed in primate lens, cornea, limbus, sclera, orbital muscle, ciliary body, retina, RPE/choroid, and RPE cells in culture. Western analysis revealed that two major groups of clusterin exist in the eye, a high molecular weight group (>100 kDa) and a second group consisting of at least five clusterin species that are all approximately 80 kDa. Analysis of conditioned media from RPE cells cultured on permeable supports suggests that different forms of clusterin display alternative patterns of secretion. CONCLUSIONS: Clusterin is expressed in a broad range of eye tissues in both human and monkey, suggesting that this is a characteristic feature in primates. We demonstrate for the first time that a diverse number of clusterin isoforms were observed in monkey eye tissues by western analysis. Meanwhile, the molecular size of clusterin mRNA detected in the array of tissues are identical in size, suggesting that the nature of the diversity in clusterin forms is due to post-translational modifications. In addition, new insights were made in defining clusterin expression in ciliary body, cornea, and the retinal pigment epithelium.
Assuntos
Proteínas Inativadoras do Complemento/genética , Proteínas do Olho/genética , Olho/metabolismo , Glicoproteínas/genética , Chaperonas Moleculares , RNA Mensageiro/biossíntese , Animais , Northern Blotting , Western Blotting , Células Cultivadas , Clusterina , Proteínas Inativadoras do Complemento/biossíntese , Proteínas do Olho/biossíntese , Expressão Gênica , Glicoproteínas/biossíntese , Humanos , Técnicas Imunoenzimáticas , Hibridização In Situ , Macaca mulatta , Peso Molecular , Epitélio Pigmentado Ocular/citologia , Epitélio Pigmentado Ocular/metabolismo , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Distribuição TecidualRESUMO
The human mitochondrial genome has not been previously known to differentially express specific mRNA transcripts. Results of northern analysis, using total RNA from two different retinal regions, demonstrate that there is differential expression of five mitochondrial genes. There is a correlation of regional expression of one of these differentially expressed genes with the gene responsible for the majority of cases of foveo-macular mitochondropathy. These findings suggest that there is selective control over specific mitochondrial messenger steady state levels.
Assuntos
DNA Mitocondrial/genética , Células Fotorreceptoras Retinianas Cones/fisiologia , Northern Blotting , Sondas de DNA , Proteínas de Ligação a DNA/genética , Expressão Gênica/fisiologia , Humanos , Isoenzimas/genética , Mitocôndrias/química , Mitocôndrias/enzimologia , Dados de Sequência Molecular , NAD/genética , RNA Mensageiro/análise , Células Fotorreceptoras Retinianas Cones/ultraestrutura , Proteínas Virais/genéticaRESUMO
OBJECTIVE: Standard therapy for significant snake envenomation includes antivenin. i.v. administration is currently the only recommended route. Intraarterial (i.a.) administration has potential advantages over i.v. that could improve outcome. To study this, the authors compared i.v. and i.a. antivenin administrations for the treatment of experimental snake envenomations. METHODS: 14 adult female swine were anesthetized and prepared with femoral artery and ear vein catheters, and baseline hoof, forearm, and thigh circumference and volume displacement measurements were taken. Crotalidae atrox venom was injected into the subcutaneous tissue of the hoof. The doses of venom were 4.75, 9.50, 19.00, 37.90, 47.30, 56.90, and 66.40 mg. Immediately following injection of venom, polyvalent antivenin (Crotalidae) (0.285 mg/10 mL saline) was infused over 30 minutes into the femoral artery (i.a. group) or ear vein (i.v. group). As a control, 10 mL of saline was infused into the ear vein (i.a. group) or femoral artery (i.v. group). Measurements were recorded up to 48 hours. Linear mixed-effect regression models were used for each measurement and to compare the i.a. and i.v. groups. RESULTS: Venom dose and time after administrations were associated with increased circumferences and increased volumes (p < 0.05). i.v. administration was associated with larger hoof (1.26 cm) and forearm (0.42 cm) sizes and volume displacement (21.71 mL) when compared with i.a. administration ( p < 0.05). CONCLUSION: i.a. antivenin results in a modest but significant decrease in tissue edema when compared with i.v..
Assuntos
Antivenenos/administração & dosagem , Mordeduras de Serpentes/terapia , Animais , Venenos de Crotalídeos , Estudos de Avaliação como Assunto , Feminino , Infusões Intra-Arteriais , Infusões Intravenosas , Projetos Piloto , SuínosRESUMO
An improved one-step method for the extraction of RNA from rat brain is described. Fresh or frozen tissue is disrupted in the powerful protein denaturant guanidine thiocyanate, and RNA isolated by ultracentrifugation through CsCl. The procedure is advantageous in that it is relatively simple, is rapid and does not expose the sample to enzyme treatments or repeated organic extractions.
Assuntos
Química Encefálica , RNA/isolamento & purificação , Animais , Centrifugação com Gradiente de Concentração/métodos , Césio , Masculino , RatosRESUMO
STUDY OBJECTIVE: To determine the incidence of blunt trauma in northern New York City before and after the distribution of 25,000 baseball bats at Yankee Stadium. DESIGN: Prospective multicenter study, including ten days before and ten days after Bat Day (June 3, 1990). SETTING: Ten emergency departments in the Bronx and northern Manhattan. TYPE OF PARTICIPANT: All patients presenting to the ED with baseball bat injuries. INTERVENTIONS: Each hospital collected the following data for each subject: date and time of injury, patient's age and sex, extent of injury, whether a Yankee bat was used, presence of loss of consciousness, results of computed tomography scan of the brain (if performed), history source, and disposition of the patient. Average daily atmospheric temperature was recorded for each day of the study. MEASUREMENTS AND MAIN RESULTS: Seventy-seven patients sustained bat injuries, 38 (49%) before and 36 (47%) after Bat Day. There were no significant differences between the two groups with respect to age, sex, time of injury, number and distribution of fractures and lacerations, incidence of loss of consciousness, source of history, or dispostion. There was a positive association between the number of cases on a given day and the average temperature that day (r = .5; P < .01). CONCLUSION: The distribution of 25,000 wooden baseball bats to attendees at Yankee Stadium did not increase the incidence of bat-related trauma in the Bronx and northern Manhattan. There was a positive correlation between daily temperature and the incidence of bat injury. The informal but common impressions of emergency clinicians about the cause-and-effect relationship between Bat Day and bat trauma were unfounded.
Assuntos
Beisebol , Ferimentos não Penetrantes/epidemiologia , Adolescente , Adulto , Idoso , Viés , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Cidade de Nova Iorque/epidemiologia , Estudos Prospectivos , TemperaturaRESUMO
An overview of emergency medical care in the New Delhi area is presented. Emergency medicine does not exist as an organized specialty, and emergency departments are staffed by a combination of residents and attending physicians from various specialties. An infrastructure for providing emergency care exists at all levels of the state-owned medical system, and in private hospitals. At every level, medical centers lack adequate resources to manage the breadth of clinical problems encountered. Tertiary EDs care for large numbers of patients with high-severity conditions. Like their Western counterparts, urban EDs in New Delhi serve a diverse population with many indigent patients. Injury and gastrointestinal illness are the most common reasons for ED use. Organized prehospital care is scanty. A survey conducted at a leading medical school and hospital in New Delhi shows medical students and physicians are highly interested in the development and practice of emergency medicine as a specialty. This interest can be nurtured through continued international collaboration.
Assuntos
Atenção à Saúde/estatística & dados numéricos , Serviços Médicos de Emergência/estatística & dados numéricos , Medicina de Emergência/organização & administração , Medicina de Emergência/educação , Medicina de Emergência/estatística & dados numéricos , Feminino , Humanos , Índia , Masculino , População UrbanaRESUMO
The base sequence complexity of total and polysomal poly(A +)RNA from rat cerebellum was measured during postnatal development by RNA-DNA hybridization. At saturation, total and polysomal poly(A +)RNA from neonate cerebellum hybridized to 12.7% and 5.0% of the single-copy genomic DNA, respectively. Assuming asymmetric transcription, the sequence complexity of these RNA populations is sufficient to code for greater than 100,000 different gene transcripts. The percentage of single-copy DNA expressed as total and polysomal poly(A +)RNA declined during postnatal development, reaching adult values of 10.0% and 4.1%, respectively. These results indicate that cerebellar maturation is accompanied by significant reductions in the diversity of genetic information expressed in the tissue.
Assuntos
Cerebelo/fisiologia , Proteínas do Tecido Nervoso/genética , RNA Mensageiro/genética , Animais , Cerebelo/crescimento & desenvolvimento , Feminino , Regulação da Expressão Gênica , Masculino , Hibridização de Ácido Nucleico , Poli A/genética , Polirribossomos/metabolismo , RNA/genética , RatosRESUMO
The mRNAs for heat shock protein 90 (HSP90) are found at highest levels (differentially expressed) in the primate retinal fovea, the region of highest visual acuity, compared to the peripheral retina. HSP90 expression and retinal associations were analyzed by immuno-localization, in situ hybridization, and western analysis. Retinal ganglion cells (RGCs) express much of the HSP90 mRNA present in the primate retinal fovea. A large fraction of RGC synthesized HSP90 is apparently present in the axonal compartment. To identify the role of HSP90 protein in the optic nerve and retina, co-immunoprecipitation experiments were performed, using antibodies specific for HSP90 isoforms. The immunoprecipitates were analyzed for neurotrophin receptor and ligand activities, and MAP kinase activity. MAP kinase assay was used to determine the activation state of MAP kinase associated with HSP90. HSP90 proteins selectively associate with the inactive form of full-length tyrosine kinase growth factor receptor trkB, suggesting utilization during anterograde axonal transport. Activated MAP kinase, associated with the trk downstream signaling cascade, was found to co-immunoprecipitate with optic nerve HSP90, suggesting that HSP90 may be utilized in retrograde transport of the secondary messengers associated with neurotrophin signaling. HSP90 can thus be hypothesized to play a role in bidirectional RGC axonal protein transport.