RESUMO
The Middle East (ME) is an ethnically and economically diverse region. A systematic review of all stroke studies conducted in the ME was carried out, with the aim of determining the prevalence of classic vascular risk factors (CRFs) across this region. Additionally, the prevalence of CRFs in the ME was compared to that of a US cohort. Prospective and retrospective ME stroke studies published from 1994 to 2014 were searched for that specifically reported on the prevalence of CRFs. The Z test for proportions was used to determine the significance of differences in CRF rates between the ME and non-ME studies. A total of 21,724 stroke patients from 13 nations in the ME were included. The prevalence rates for CRFs in the ME stroke population were hypertension, 62.1%; diabetes, 33.1%; dyslipidaemia, 36.8%; ischaemic heart disease, 24.6%; smoking, 19.3%; and atrial fibrillation, 13.6%. Compared to the US cohort, ME patients had a lower prevalence of all CRFs except diabetes (P < 0.0001) and smoking (P = 0.05). Compared with stroke patients in the USA, those in the ME have a significantly higher prevalence of diabetes and smoking. Education and lifestyle modification is perhaps the most effective strategy in reducing the risk of stroke in this population.
Assuntos
Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus/epidemiologia , Dislipidemias/epidemiologia , Fumar/epidemiologia , Acidente Vascular Cerebral/epidemiologia , Humanos , Oriente Médio/epidemiologia , Prevalência , Estados Unidos/epidemiologiaRESUMO
Agility is important for sport performance and potentially injury risk; however, factors affecting this motor skill remain unclear. Here, we evaluated the extent to which lower extremity dexterity (LED) and muscle performance were associated with agility. Fourteen male and 14 female soccer athletes participated. Agility was evaluated using a hopping sequence separately with both limbs and with the dominant limb only. The LED test evaluated the athletes' ability to dynamically regulate foot-ground interactions by compressing a spring prone to buckling with the lower limb. Muscle performance included hip and knee isometric strength and vertical jump height. Correlation analyses were used to assess the associations between muscle performance, LED, and agility. Multiple regression models were used to determine whether linear associations differed between sexes. On average, the female athletes took longer to complete the agility tasks than the male athletes. This difference could not be explained by muscle performance. Conversely, LED was found to be the primary determinant of agility (double limb: R(2) = 0.61, P < 0.001; single limb: R(2) = 0.63, P < 0.001). Our findings suggest that the sensorimotor ability to dynamically regulate foot-ground interactions as assessed by the LED test is predictive of agility in soccer athletes. We propose that LED may have implications for sport performance, injury risk, and rehabilitation.
Assuntos
Desempenho Atlético/fisiologia , Extremidade Inferior/fisiologia , Destreza Motora/fisiologia , Músculo Esquelético/fisiologia , Futebol/fisiologia , Adolescente , Feminino , Humanos , Masculino , Força Muscular/fisiologia , Análise de Regressão , Fatores SexuaisRESUMO
This report aims to evaluate the usefulness of self-sampling as an approach for future national surveillance of emerging respiratory infections by comparing virological data from two parallel surveillance schemes in England. Nasal swabs were obtained via self-administered sampling from consenting adults (≥ 16 years-old) with influenza symptoms who had contacted the National Pandemic Flu Service (NPFS) health line during the 2009 influenza pandemic. Equivalent samples submitted by sentinel general practitioners participating in the national influenza surveillance scheme run jointly by the Royal College of General Practitioners (RCGP) and Health Protection Agency were also obtained. When comparable samples were analysed there was no significant difference in results obtained from self-sampling and clinician-led sampling schemes. These results demonstrate that self-sampling can be applied in a responsive and flexible manner, to supplement sentinel clinician-based sampling, to achieve a wide spread and geographically representative way of assessing community transmission of a known organism.
Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/virologia , Autoadministração/métodos , Vigilância de Evento Sentinela , Manejo de Espécimes/métodos , Adulto , Inglaterra/epidemiologia , Feminino , Humanos , Influenza Humana/diagnóstico , Influenza Humana/epidemiologia , Masculino , Cavidade Nasal/virologia , Pandemias , RNA Viral/genética , Características de Residência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Inquéritos e QuestionáriosRESUMO
Altered hip and knee kinematics in the frontal and transverse planes may increase patellofemoral joint stress and contribute to the development of patellofemoral pain. The purpose of this cross-sectional study was to evaluate the association among hip and knee kinematics, pain, and self-reported functional status in males and females with patellofemoral pain. 20 males and 20 females with patellofemoral pain participated in this study. 3-dimensional hip and knee kinematics were quantified while performing a step-down task. A visual analogue scale was used to evaluate usual knee pain. The anterior knee pain scale was used to evaluate the knee functional score. For both groups combined, greater usual pain was associated with greater peak hip adduction, hip internal rotation and knee abduction (r=0.54-0.57, P<0.001). Also, modest to low correlations (r=-0.48 to - 0.37, P=0.03-0.08) were found among hip and knee kinematics and functional score. Stepwise regression revealed that peak hip internal rotation and hip adduction were significant predictors of pain, while peak hip adduction was the only predictor of function. Greater hip adduction, hip internal rotation and knee abduction are associated with higher levels of pain and reduced function in males and females with patellofemoral pain.
Assuntos
Articulação do Quadril/fisiopatologia , Articulação do Joelho/fisiopatologia , Síndrome da Dor Patelofemoral/fisiopatologia , Adolescente , Adulto , Fenômenos Biomecânicos , Estudos Transversais , Feminino , Humanos , Imageamento Tridimensional , Masculino , Medição da Dor , Articulação Patelofemoral/fisiopatologia , Análise de Regressão , Autorrelato , Adulto JovemRESUMO
During landing and cutting, females exhibit greater frontal plane moments at the knee (internal knee adductor moments or external knee abduction moments) and favor the use of the knee extensors over the hip extensors to attenuate impact forces when compared with males. However, it is not known when this biomechanical profile emerges. The purpose of this study was to compare landing biomechanics between sexes across maturation levels. One hundred and nineteen male and female soccer players (9-22 years) participated. Subjects were grouped based on maturational development. Lower extremity kinematics and kinetics were obtained during a drop-land task. Dependent variables included the average internal knee adductor moment and sagittal plane knee/hip moment and energy absorption ratios during the deceleration phase of landing. When averaged across maturation levels, females demonstrated greater internal knee adductor moments (0.06±0.03 vs 0.01±0.02 N m/kg m; P<0.005), knee/hip extensor moment ratios (2.0±0.1 vs 1.4±0.1 N m/kg m; P<0.001) and knee/hip energy absorption ratios (2.9±0.1 vs 1.96±0.1 N m/kg m; P<0.001) compared with males. Higher knee adductor moments combined with disproportionate use of knee extensors relative to hip extensors observed in females reflect a biomechanical pattern that increases anterior cruciate ligament loading. This biomechanical strategy already was established in pre-pubertal female athletes.
Assuntos
Lesões do Ligamento Cruzado Anterior , Articulação do Joelho/fisiologia , Desenvolvimento Musculoesquelético , Adolescente , Fatores Etários , Fenômenos Biomecânicos , Criança , Feminino , Humanos , Masculino , Fatores Sexuais , Futebol/fisiologia , Adulto JovemRESUMO
Tamoxifen is a selective estrogen receptor (ER) modulator, but it is also a deactivating ligand for estrogen-related receptor-γ (ERRγ) and a full agonist for the G protein-coupled estrogen receptor (GPER). Fulvestrant is a selective ER down-regulator that lacks agonist effects on ERα/ERß, is inactive on ERRγ, but acts as a full agonist on GPER. Fulvestrant effects on tamoxifen actions on uterine and somatic growth, bone, the growth hormone (GH)-insulin-like growth factor I (IGF-I) axis, and pituitary prolactin were analyzed to pharmacologically discriminate tamoxifen effects that may be mediated by ERα/ERß versus ERRγ versus GPER. Ovariectomized rats received tamoxifen (0.6 mg/kg/daily) plus fulvestrant at 0, 3, 6, or 12 mg/kg/daily for 5 weeks; controls received vehicle or 6 mg/kg fulvestrant daily. Tamoxifen effects to increase uterine weight, decrease serum IGF-I, increase pituitary prolactin, and increase bone mineral density could be fully blocked by fulvestrant, indicating mediation by ERα/ERß. Tamoxifen effects to decrease pituitary GH, tibia length, and body weight were only partially blocked by fulvestrant, indicating involvement of mechanisms unrelated to ERα/ERß. Fulvestrant did not inhibit tamoxifen actions to reduce total pituitary protein, again indicating effects not mediated by ERα/ERß. Tamoxifen actions to reduce serum GH were mimicked rather than inhibited by fulvestrant, pharmacological features consistent with GPER involvement. However, fulvestrant alone increased IGF-I and also blocked tamoxifen-evoked IGF-I decreases; thus fulvestrant effects on serum GH might reflect increased IGF-I feedback inhibition. Fulvestrant alone had no effect on the other parameters. The findings indicate that mechanisms unrelated to ERα/ERß contribute to tamoxifen effects on body weight, bone growth, and pituitary function.
Assuntos
Desenvolvimento Ósseo/fisiologia , Estradiol/análogos & derivados , Receptor alfa de Estrogênio/fisiologia , Receptor beta de Estrogênio/fisiologia , Receptores de Estrogênio/fisiologia , Receptores Acoplados a Proteínas G/fisiologia , Tamoxifeno/farmacologia , Animais , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Desenvolvimento Ósseo/efeitos dos fármacos , Estradiol/farmacologia , Feminino , Fulvestranto , Ovariectomia , Hipófise/efeitos dos fármacos , Hipófise/fisiologia , Distribuição Aleatória , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVE: To test the hypothesis that individuals with patellofemoral pain (PFP) exhibit greater patellofemoral joint stress profiles compared to persons who are pain-free. METHODS: Ten females with PFP and ten gender, age, and activity-matched pain-free controls participated. Patella and femur stress profiles were quantified utilizing subject-specific finite element (FE) models of the patellofemoral joint at 15° and 45° of knee flexion. Input parameters for the FE model included: (1) joint geometry, (2) quadriceps muscle forces, and (3) weight-bearing patellofemoral joint kinematics. Using a nonlinear FE solver, quasi-static loading simulations were performed to quantify each subject's patellofemoral joint stress profile during a static squatting maneuver. The patella and femur peak and mean hydrostatic pressure as well as the peak and mean octahedral shear stress for the elements representing the chondro-osseous interface were quantified. RESULTS: Compared to the pain-free controls, individuals with PFP consistently exhibited greater peak and mean hydrostatic pressure as well as peak and mean octahedral shear stress for the elements representing the patella and femur chondro-osseous interface across the two knee flexion angles tested (15° and 45°). CONCLUSIONS: The combined finding of elevated hydrostatic pressure and octahedral shear stress across the two knee flexion angles supports the premise that PFP may be associated with elevated joint stress. Therefore, treatments aimed at decreasing patellofemoral joint stress may be indicated in this patient population.
Assuntos
Dor/fisiopatologia , Articulação Patelofemoral/fisiopatologia , Estresse Mecânico , Adulto , Fenômenos Biomecânicos , Cartilagem Articular/fisiopatologia , Feminino , Análise de Elementos Finitos , Humanos , Pressão Hidrostática , Imageamento por Ressonância Magnética , Masculino , Modelos AnatômicosRESUMO
Research suggests that early classroom experiences influence the socialization of aggression. Tracking changes in the aggressive behavior of 4,179 children from kindergarten to second-grade (ages 5-8), this study examined the impact of 2 important features of the classroom context--aggregate peer aggression and climates characterized by supportive teacher-student interactions. The aggregate aggression scores of children assigned to first-grade classrooms predicted the level of classroom aggression (assessed by teacher ratings) and quality of classroom climate (assessed by observers) that emerged by the end of Grade 1. Hierarchical linear model analyses revealed that first-grade classroom aggression and quality of classroom climate made independent contributions to changes in student aggression, as students moved from kindergarten to second grade. Implications for policy and practice are discussed.
Assuntos
Agressão/psicologia , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/psicologia , Grupo Associado , Meio Social , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Determinação da Personalidade , Fatores de Risco , Facilitação Social , Socialização , EnsinoRESUMO
1. Much evidence exists detailing how animals respond to pathogen challenge, yet information explaining how the various behavioural, immunological, and physiological systems in chickens interplay during such challenges remains limited. 2. To gain an understanding of this interplay while controlling for genetic variation, the current study collected a variety of behavioural, physiological and immunological measures from three inbred lines (P, O and N) of laying hens before and after a sub-clinical infection with Salmonella enterica Typhimurium at 56 d of age. For comparison, an equal number of control birds were inoculated with a Salmonella-free broth. To identify an underlying profile, which might result in reduced susceptibility to infection, data were also collected in the pre-infection period. Post-infection blood and faeces were collected at 1-d post infection (dpi) and faeces again at 8 dpi. Animals were killed 15 d after infection and faeces, caecal contents, and spleen were examined for the presence of Salmonella. 3. Statistical analysis was performed to identify pre- and post-infection differences between genetic lines, changes in bird behavioural patterns between the two periods, and associations between a positive test for Salmonella and the various response measures. 4. Tissues from Line P birds were more often negative for Salmonella than those from birds of other lines, though this was inconsistent and tissue-dependent. The P line was also characterised by relatively greater serum concentrations of immunoglobulins at 1 dpi and α(1)-acid glycoprotein at 15 dpi. In addition, P line birds were more timid and their growth was reduced during the pre-infection period suggesting the possibility of a profile with reduced susceptibility to the bacterial challenge. 5. The current work has identified correlations between attributes of chicken strains and improved clearance. Future work using hypothesis-based testing will be required to determine whether the identified correlations are causally related.
Assuntos
Comportamento Animal , Doenças das Aves/microbiologia , Galinhas/microbiologia , Salmonelose Animal/imunologia , Bem-Estar do Animal , Animais , Doenças das Aves/imunologia , Peso Corporal , Galinhas/imunologia , Galinhas/fisiologia , Suscetibilidade a Doenças , Feminino , Glucocorticoides/metabolismo , Imunoglobulina M/sangue , Imunoglobulinas/sangue , Masculino , Orosomucoide/metabolismoRESUMO
AIMS/HYPOTHESIS: The aim of the study was to determine the association between IRS1 G972R polymorphism and type 2 diabetes; published data concerning this association have been conflicting. To obtain further insight into this topic, we performed a meta-analysis of all available case-control studies. METHODS: We performed a meta-analysis of 32 studies (12,076 cases and 11,285 controls). RESULTS: The relatively infrequent R972 variant was not significantly associated with type 2 diabetes (OR 1.09, 95% CI 0.96-1.23, p = 0.184 under a dominant model). Some evidence of heterogeneity was observed across studies (p = 0.1). In the 14 studies (9,713 individuals) in which the mean age at type 2 diabetes diagnosis was available, this variable explained 52% of the heterogeneity (p = 0.03). When these studies were subdivided into tertiles of mean age at diagnosis, the OR for diabetes was 1.48 (95% CI 1.17-1.87), 1.22 (95% CI 0.97-1.53) and 0.88 (95% CI 0.68-1.13) in the youngest, intermediate and oldest tertile, respectively (p = 0.0022 for trend of ORs). CONCLUSIONS/INTERPRETATION: Our findings illustrate the difficulties of ascertaining the contribution of 'low-frequency-low-risk' variants to type 2 diabetes susceptibility. In the specific context of the R972 variant, approximately 200,000 study individuals would be needed to have 80% power to identify a 9% increase in diabetes risk at a genome-wide significance level. Under these circumstances, a strategy aimed at improving outcome definition and decreasing its heterogeneity may critically enhance our ability to detect genetic effects, thereby decreasing the required sample size. Our data suggest that focusing on early-onset diabetes, which is characterised by a stronger genetic background, may be part of such a strategy.
Assuntos
Diabetes Mellitus Tipo 2/genética , Frequência do Gene , Predisposição Genética para Doença , Proteínas Substratos do Receptor de Insulina/genética , Polimorfismo Genético , Polimorfismo de Nucleotídeo Único , Idade de Início , Substituição de Aminoácidos , Estudos de Casos e Controles , DNA/sangue , DNA/genética , DNA/isolamento & purificação , Variação Genética , Humanos , Metanálise como Assunto , Razão de Chances , Valores de Referência , Tamanho da AmostraRESUMO
Human cytomegalovirus (HCMV) has become a paradigm for viral immune evasion due to its unique multitude of immune-modulatory strategies. HCMV modulates the innate as well as adaptive immune response at every step of its life cycle. It dampens the induction of antiviral interferon-induced genes by several mechanisms. Further striking is the multitude of genes and strategies devoted to modulating and escaping the cellular immune response. Several genes are independently capable of inhibiting antigen presentation to cytolytic T cells by downregulating MHC class I. Recent data revealed an astounding variety of methods in triggering or inhibiting activatory and inhibitory receptors found on NK cells, NKT cells, T cells as well as auxiliary cells of the immune system. The multitude and complexity of these mechanisms is fascinating and continues to reveal novel insights into the host-pathogen interaction and novel cell biological and immunological concepts.
Assuntos
Citomegalovirus/imunologia , Citomegalovirus/fisiologia , Antígenos de Histocompatibilidade Classe I/imunologia , Interferons/antagonistas & inibidores , Receptores Imunológicos/antagonistas & inibidores , Humanos , Células Matadoras Naturais/imunologia , Linfócitos T Citotóxicos/imunologiaRESUMO
Considerable evidence indicates that mRNA associates with structural filaments in the cell (cytoskeleton). This relationship would be an important mechanism to effect mRNA sorting since specific mRNAs could be sequestered at sites within the cell. In addition, it can provide a mechanism for spatial regulation of mRNA expression. However, the precise structural interactions between mRNA and the cytoskeleton have yet to be defined. An objective of this work was to visualize "individual" poly(A) mRNA molecules in situ by electron microscopy to identify their relationship to individual filaments. Poly(A) RNA and filaments were identified simultaneously using antibodies to detect hybridized probe and filaments or actin-binding proteins. In human fibroblasts, most of the poly(A) mRNA (72%) was localized within 5 nm of orthogonal networks of F-actin filaments. Poly(A) mRNA also colocalized with vimentin filaments (29%) and microtubules (< 10%). The sites of mRNA localization were predominantly at filament intersections. The majority of poly(A) mRNA and polysomes colocalized with the actin crosslinking proteins, filamin, and alpha-actinin, and the elongation factor, EF-1 alpha (actin-binding protein; ABP-50). Evidence that intersections contained single mRNA molecules was provided by using a labeled oligo dT probe to prime the synthesis of cDNA in situ using reverse transcriptase. Both the poly(A) and cis sequences of the same mRNA molecule could then be visualized independently. We propose that the cytoskeletal intersection is a mRNA receptor and serves as a "microdomain" where mRNA is attached and functionally expressed.
Assuntos
Actinas/análise , Poli A/análise , Poli A/biossíntese , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Animais , Sequência de Bases , Embrião de Galinha , Citoplasma/ultraestrutura , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibroblastos/ultraestrutura , Humanos , Imuno-Histoquímica , Hibridização In Situ , Microscopia Imunoeletrônica/métodos , Sondas de Oligonucleotídeos , Transcrição GênicaRESUMO
Tpr is a 270-kD coiled-coil protein localized to intranuclear filaments of the nuclear pore complex (NPC). The mechanism by which Tpr contributes to the structure and function of the nuclear pore is currently unknown. To gain insight into Tpr function, we expressed the full-length protein and several subdomains in mammalian cell lines and examined their effects on nuclear pore function. Through this analysis, we identified an NH2-terminal domain that was sufficient for association with the nucleoplasmic aspect of the NPC. In addition, we unexpectedly found that the acidic COOH terminus was efficiently transported into the nuclear interior, an event that was apparently mediated by a putative nuclear localization sequence. Ectopic expression of the full-length Tpr caused a dramatic accumulation of poly(A)+ RNA within the nucleus. Similar results were observed with domains that localized to the NPC and the nuclear interior. In contrast, expression of these proteins did not appear to affect nuclear import. These data are consistent with a model in which Tpr is tethered to intranuclear filaments of the NPC by its coiled coil domain leaving the acidic COOH terminus free to interact with soluble transport factors and mediate export of macromolecules from the nucleus.
Assuntos
Membrana Nuclear/metabolismo , Proteínas Nucleares/fisiologia , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas/fisiologia , RNA Mensageiro/metabolismo , Animais , Transporte Biológico , Células COS , Linhagem Celular , Núcleo Celular/metabolismo , Cricetinae , Células HeLa , Humanos , Imuno-Histoquímica , Rim , Substâncias Macromoleculares , Mesocricetus , Microscopia de Fluorescência , Microscopia Imunoeletrônica , Modelos Biológicos , Membrana Nuclear/ultraestrutura , Complexo de Proteínas Formadoras de Poros Nucleares , Proteínas Nucleares/química , Ligação Proteica , Proteínas/metabolismo , Proteínas Proto-Oncogênicas/química , Deleção de Sequência , Relação Estrutura-Atividade , TransfecçãoRESUMO
Polychlorinated biphenyls at concentrations of 1 to 10 micrograms per liter reduced phytoplankton biomass and size in natural estuarine phytoplankton communities grown within dialysis bags in situ in an estuarine marsh. In polychlorinated biphenyls-contaminated waters, these changes could increase the number of trophic levels and divert the flow of biomass from harvestable fish to jellyfish and other gelatinous predators.
Assuntos
Fitoplâncton/efeitos dos fármacos , Plâncton/efeitos dos fármacos , Bifenilos Policlorados/farmacologia , Poluentes Químicos da Água/toxicidade , Poluentes da Água/toxicidade , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Fotossíntese/efeitos dos fármacos , Fitoplâncton/citologia , Fitoplâncton/metabolismoRESUMO
BACKGROUND AND PURPOSE: The optimal patient sedation during mechanical thrombectomy for ischemic stroke in the extended time window is unknown. The purpose of this study was to assess the impact of patient sedation on outcome in patients undergoing thrombectomy 6-16 hours from stroke onset. MATERIALS AND METHODS: Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE 3) was a multicenter, randomized, open-label trial of thrombectomy for ICA and M1 occlusions in patients 6-16 hours from stroke onset. Subjects underwent thrombectomy with either general anesthesia or conscious sedation at the discretion of the treating institution. RESULTS: Of the 92 patients who were randomized to intervention, 26 (28%) underwent thrombectomy with general anesthesia and 66 (72%) underwent thrombectomy with conscious sedation. Baseline clinical and imaging characteristics were similar among all groups. Functional independence at 90 days was 23% for general anesthesia, 53% for conscious sedation, and 17% for medical management (P = .009 for general anesthesia versus conscious sedation). Conscious sedation was associated with a shorter time from arrival in the angiosuite to femoral puncture (median, 14 versus 18 minutes; P = 0.05) and a shorter time from femoral puncture to reperfusion (median, 36 versus 48 minutes; P = .004). Sixty-six patients were treated at sites that exclusively used general anesthesia (n = 14) or conscious sedation (n = 52). For these patients, functional independence at 90 days was significantly higher in the conscious sedation subgroup (58%) compared with the general anesthesia subgroup (21%) (P = .03). CONCLUSIONS: Patients who underwent thrombectomy with conscious sedation in the extended time window experienced a higher likelihood of functional independence at 90 days, a lower NIHSS score at 24 hours, and a shorter time from femoral puncture to reperfusion compared with those who had general anesthesia. This effect remained robust in institutions that only treated patients with a single anesthesia technique.
Assuntos
Anestesia Geral/métodos , Sedação Consciente/métodos , Procedimentos Endovasculares/métodos , Acidente Vascular Cerebral/cirurgia , Trombectomia/métodos , Idoso , Isquemia Encefálica/complicações , Isquemia Encefálica/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/etiologia , Resultado do TratamentoRESUMO
High rates of aggressive-disruptive behavior exhibited by children during their initial years of elementary school increase their risk for significant behavioral adjustment problems with teachers and peers. The purpose of the present study was to examine the unique and combined contributions of child vulnerabilities and school context to the development of aggressive-disruptive student behavior during first grade. Parent ratings and child interviews assessed three child characteristics associated with risk for the development of aggressive behavior problems in elementary school (aggressive-disruptive behaviors at home, attention problems, and social cognitions) in a sample of 755 first-grade children in four demographically diverse American communities. Two school characteristics associated with student aggressive-disruptive behavior problems (low-quality classroom context, school poverty levels) were also assessed. Linear and multilevel analyses showed that both child and school characteristics made independent and cumulative contributions to the development of student aggressive-disruptive behavior at school. Although rates of student aggressive-disruptive behavior varied by gender and race, the predictive model generalized across all groups of children in the study.
RESUMO
VEGF is a secreted mitogen associated with angiogenesis and is also a potent vascular permeability factor. The biological role of VEGF in the ischemic brain remains unknown. This study was undertaken to investigate whether VEGF enhances cerebral microvascular perfusion and increases blood-brain barrier (BBB) leakage in the ischemic brain. Using magnetic resonance imaging (MRI), three-dimensional laser-scanning confocal microscope, and functional neurological tests, we measured the effects of administrating recombinant human VEGF(165) (rhVEGF(165)) on angiogenesis, functional neurological outcome, and BBB leakage in a rat model of focal cerebral embolic ischemia. Late (48 hours) administration of rhVEGF(165) to the ischemic rats enhanced angiogenesis in the ischemic penumbra and significantly improved neurological recovery. However, early postischemic (1 hour) administration of rhVEGF(165) to ischemic rats significantly increased BBB leakage, hemorrhagic transformation, and ischemic lesions. Administration of rhVEGF(165) to ischemic rats did not change BBB leakage and cerebral plasma perfusion in the contralateral hemisphere. Our results indicate that VEGF can markedly enhance angiogenesis in the ischemic brain and reduce neurological deficits during stroke recovery and that inhibition of VEGF at the acute stage of stroke may reduce the BBB permeability and the risk of hemorrhagic transformation after focal cerebral ischemia.
Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Isquemia Encefálica/fisiopatologia , Fatores de Crescimento Endotelial/farmacologia , Linfocinas/farmacologia , Neovascularização Patológica/induzido quimicamente , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Microcirculação/efeitos dos fármacos , Ratos , Ratos Wistar , Fluxo Sanguíneo Regional , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Chickens infected with Salmonella enterica serovars Typhimurium (ST) and Enteritidis (SE) still represent a major source of human food poisoning via consumption of contaminated meat and eggs. Vaccination represents a sustainable approach to control Salmonella in the chicken and the serovar specificity of immunity has the potential to impact on the need for multivalent vaccines. The issue of cross-reactive immune responses and cross-serovar protection was examined in these experiments. Cellular and humoral immune responses were measured by antigen-specific ELISA and splenocyte proliferation assays during primary infections (with ST and SE) and during a second challenge with homologous or heterologous serovars. Primary infection with ST or SE induced strong lymphocyte proliferation and high levels of specific antibody (IgM, IgG and IgA) responses with substantial serovar cross-reactivity. The occurrence of high levels of splenocyte proliferation and strong antibody responses corresponded to the initiation of clearance with both ST and SE. Re-challenge of ST and SE infection-primed chickens with either serovar resulted in significant levels of protection (assessed by bacterial numbers and rate of clearance) with little difference between homologous or heterologous challenge schedules. Relatively low levels of antigen-specific splenocyte proliferation were detected during secondary infection, which may be caused by splenic T cells exiting to the gut. In contrast, the more rapid specific antibody responses (compared with primary infection controls) indicate the development of a secondary antigen-specific adaptive response. The substantial level of cross-protection between serovars and the level of antigenic cross-reactivity indicates the potential for single serovar live vaccines to protect against both group B and D salmonellae.
Assuntos
Galinhas/imunologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/imunologia , Salmonella enteritidis/imunologia , Salmonella typhimurium/imunologia , Animais , Ceco/imunologia , Ceco/microbiologia , Proliferação de Células , Reações Cruzadas/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Fezes/microbiologia , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Doenças das Aves Domésticas/prevenção & controle , Distribuição Aleatória , Salmonelose Animal/microbiologia , Salmonelose Animal/prevenção & controle , Organismos Livres de Patógenos Específicos , Baço/imunologia , Baço/microbiologia , Linfócitos T/citologia , Linfócitos T/imunologiaRESUMO
BACKGROUND: Angiogenesis (the formation of new blood vessels) is necessary for tumor growth and metastasis. PURPOSE: We investigated whether angiogenesis as measured by microvessel count (MVC) predicts clinical outcome in a series of patients with axillary lymph node-negative breast cancer who received no adjuvant therapy and who were followed for a long period of time. Our long-term goal is to identify those patients who may or may not need adjuvant chemotherapy. METHODS: Pathologic archival material and clinical information were analyzed for 167 patients treated with mastectomy from 1941 through 1987; none received adjuvant treatment. The median follow-up time among living patients was 15.4 years (range, 2.6-35.8 years). Ninety-six (58%) patients had a tumor size of 2 cm or less, 52 (31%) had tumors of 2.1-3 cm, and 19 (11%) had tumors of larger than 3 cm. Paraffin-embedded tissue sections were stained for expression of CD34 antigen on microvessel-associated endothelial cells by use of a monoclonal anti-CD34 antibody. Vascularity was defined as the number of microvessels (average of the three highest counts) per high-power microscopic field (400 x magnification) in the area of highest vascular density. A high vascular count was defined as 15 or more microvessels per field. Actuarial survival curves were calculated according to the Kaplan-Meier method and comparisons were made with the logrank test. The Cox proportional hazards model was used for multivariate analysis. All P values were based on two-sided testing. RESULTS: The 20-year disease-free survival (DFS) for the 167 node-negative patients treated with mastectomy and no adjuvant therapy was 74.8% (95% confidence interval [CI] = 64.7%-82.0%). The 20-year DFS was 93.1% (95% CI = 79.9%-97.7%) if the MVC was low versus 68.9% (95% CI = 56.8%-78.0%) if the MVC was high (P = .018). This difference was maintained irrespective of tumor size: for tumor size of 2 cm or less (93.3% [95% CI = 75.3%-98.3%] versus versus 67.8% [95% CI = 50.1%-80.3%]) and for tumor size of larger than 2 cm (92.3% [95% CI = 56.6%-98.9%] versus 70.9% [95% CI = 54.6%-81.6%]). However, the likelihood of a high MVC was greater with large tumors (P = .05). The proportions of tumors with low and high MVC were 33% and 67%, respectively, if the tumor size was 2 cm or less, and 20% and 80%, respectively, if tumor size was larger than 2 cm. There was no significant difference in the 20-year DFS as a function of tumor grade (P = .2). After combining patients with tumors of nuclear grades 2 and 3 compared with those of nuclear grade 1, the 20-year DFS was 93.9% (95% CI = 77.2%-98.4%) for low MVC versus 66.9% (95% CI = 52.2%-78.0%) for high MVC (P = .02). In a multivariate analysis that included the variables tumor size, age, nuclear grade, estrogen receptor status, and MVC, only MVC appeared to be an independent prognostic indicator (P = .04). CONCLUSIONS: Angiogenesis as measured by MVC is a reliable independent prognostic marker of long-term survival in patients with node-negative breast cancer. The prognostic usefulness of this marker is maintained after more than 15 years of follow-up. A low MVC identifies a subgroup of patients with DFS of 92% or more, independent of tumor size or grade.
Assuntos
Neoplasias da Mama/irrigação sanguínea , Neovascularização Patológica , Adulto , Idoso , Análise de Variância , Neoplasias da Mama/patologia , Intervalo Livre de Doença , Feminino , Humanos , Imuno-Histoquímica , Metástase Linfática , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Modelos de Riscos ProporcionaisRESUMO
Glandular kallikrein (a trypsin-like serine protease) is an estrogen-induced and dopamine-repressed protein in the rat anterior pituitary which appears to be associated with lactotrophs. This study examined glandular kallikrein levels in diethylstilbestrol (DES)-induced pituitary tumors in F344 rats and compared it to plasma and pituitary prolactin, and pituitary wet weight. Ovariectomized F344 rats were implanted with Silastic tubes containing 0 or 5 mg DES for 1, 3, 5, 7, or 9 weeks. Glandular kallikrein was measured by microenzymatic assay using D-valylleucylarginyl-p-nitroanilide following trypsin treatment of extracts to activate latent forms of glandular kallikrein. Prolactin was measured by radioimmunoassay. DES induced steady time-dependent increases in pituitary wet weight with 7- and 16-fold increases observed by 5 and 9 weeks, respectively. Growth rates averaged 11.4 mg/week during the first 5 weeks of DES exposure, and then increased to 23.2 mg/week between weeks 5 and 9. Glandular kallikrein total activity (nmol/min/pituitary) increased 130- and 240-fold after 3 and 5 weeks of DES exposure, respectively, and then abruptly plateaued. The specific activity (nmol/min/mg protein) of glandular kallikrein peaked at 3-5 weeks (36-fold increase compared to controls) and then declined as pituitary protein but not glandular kallikrein continued to increase. Total pituitary prolactin constantly rose during DES exposure with 12- and 26-fold increases after 5 and 9 weeks, respectively. Plasma prolactin levels also continuously rose during exposure to DES with 130- and 290-fold increases after 5 and 9 weeks, respectively. No major strain differences were found with regard to sensitivity to the acute effects of estrogen or dopaminergic stimulation on glandular kallikrein induction. DES-induced pituitary tumors in F344 rats are well known to arise via lactotroph proliferation, and the striking elevation in glandular kallikrein and prolactin during the early phases of tumor growth provide further support for a localization of glandular kallikrein in lactotrophs. However, the abrupt stabilization in glandular kallikrein levels by week 5 was unexpected and may signal a biochemical transformation of the tissue during tumor progression.