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BACKGROUND: In a context of the evolution of severe morbidities in patients living with HIV (PLWH), the aim of this study was to describe reasons for hospitalization and the mode of care for the patients requiring hospitalization. METHODS: All admissions (≥24h) of PLWH to 10 hospitals in the south of Paris (COREVIH Ile-de-France Sud) between 1/1/2011 and 12/31/2011 were identified. The hospital database and the file of patients followed in the HIV referral department of each hospital were matched. Detailed clinical and biological data were collected, by returning to the individual medical records, for a random sample (65% of hospitalized patients). RESULTS: A total of 3013 hospitalizations (1489 patients) were recorded in 2011. The estimated rate of hospitalized patients was about 8% among the 10105 PLWH routinely managed in COREVIH Ile-de-France Sud in 2011. The majority (58.5%) of these hospitalizations occurred in a unit other than the HIV referral unit. Non-AIDS-defining infections were the main reason for admission (16.4%), followed by HIV-related diseases (15.6%), hepatic/gastrointestinal diseases (12.0%), and cardiovascular diseases (10.3%). The median length of stay was 5 days overall (IQR: 2-11), it was longer among patients admitted to a referral HIV care unit than to another ward. HIV infection had been diagnosed >10 years previously in 61.4% of these hospitalized patients. They often had associated comorbidities (coinfection HCV/HVB 40.5%, smoking 45.8%; hypertension 33.4%, dyslipidemia 28.8%, diabetes 14.8%). Subjects over 60 years old accounted for 15% of hospitalized patients, most of them were virologically controlled under HIV treatment, and cardiovascular diseases were their leading reason for admission. CONCLUSION: Needs for hospitalization among PLWH remain important, with a wide variety in causes of admission, involving all hospital departments. It is essential to prevent comorbidities to reduce these hospitalizations, and to maintain a link between the management of PLWH, that becomes rightly, increasing ambulatory, and recourse to specialized inpatient services.
Assuntos
Atenção à Saúde/estatística & dados numéricos , Infecções por HIV/epidemiologia , Necessidades e Demandas de Serviços de Saúde , Hospitalização/estatística & dados numéricos , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Adulto , Comorbidade , Atenção à Saúde/normas , Feminino , Infecções por HIV/complicações , HIV-1 , Necessidades e Demandas de Serviços de Saúde/estatística & dados numéricos , Necessidades e Demandas de Serviços de Saúde/tendências , Departamentos Hospitalares/estatística & dados numéricos , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Paris/epidemiologia , Adulto JovemRESUMO
As part of an international intercomparison project, the weak temperature gradient (WTG) and damped gravity wave (DGW) methods are used to parameterize large-scale dynamics in a set of cloud-resolving models (CRMs) and single column models (SCMs). The WTG or DGW method is implemented using a configuration that couples a model to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. We investigated the sensitivity of each model to changes in SST, given a fixed reference state. We performed a systematic comparison of the WTG and DGW methods in different models, and a systematic comparison of the behavior of those models using the WTG method and the DGW method. The sensitivity to the SST depends on both the large-scale parameterization method and the choice of the cloud model. In general, SCMs display a wider range of behaviors than CRMs. All CRMs using either the WTG or DGW method show an increase of precipitation with SST, while SCMs show sensitivities which are not always monotonic. CRMs using either the WTG or DGW method show a similar relationship between mean precipitation rate and column-relative humidity, while SCMs exhibit a much wider range of behaviors. DGW simulations produce large-scale velocity profiles which are smoother and less top-heavy compared to those produced by the WTG simulations. These large-scale parameterization methods provide a useful tool to identify the impact of parameterization differences on model behavior in the presence of two-way feedback between convection and the large-scale circulation.
RESUMO
As part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistent implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.
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BACKGROUND: The increase in CD4 count may reach a plateau after some duration of virological response to highly active antiretroviral therapy (HAART). METHODS: A total of 1281 HIV-infected patients initiating HAART were enrolled in the AntiPROtease (APROCO) cohort. We investigated determinants of increase in CD4 count using longitudinal mixed models in patients who maintained a plasma HIV RNA <500 HIV-1 RNA copies/mL. RESULTS: A total of 870 patients had a virological response at month 4. The median follow-up time was 57 months. Mean estimated increases in CD4 count in patients with persistent virological response were 29.9 cells/muL/month before month 4, 6.4 cells/microL/month between months 4 and 36, and 0.7 cells/microL/month (not significantly different from 0) after month 36. Three factors were associated with a significantly positive CD4 count slope after month 36: male gender (+0.9), no history of antiretroviral therapy at baseline (+1.7) and baseline CD4 count <100 cells/microL (+2.6). In patients who maintained a virological response after 5 years of HAART, a CD4 count >500 cells/microL was achieved in 83% of those with a baseline CD4 count >or=200 cells/microL and in 45% of those with a baseline CD4 count <200 cells/microL. CONCLUSION: The increase in CD4 count reaches a plateau after 3 years of virological response. Even if patients initiating HAART with low CD4 counts still show a CD4 count increase after 3 years, it remains insufficient to overcome immune deficiency in all patients.
Assuntos
Terapia Antirretroviral de Alta Atividade/métodos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , HIV-1/crescimento & desenvolvimento , RNA Viral/sangue , Adulto , Contagem de Linfócito CD4 , Estudos de Coortes , Feminino , Infecções por HIV/virologia , HIV-1/genética , HIV-1/imunologia , Humanos , Modelos Lineares , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos ProspectivosRESUMO
The influence of HAART on the survival of patients with AIDS-related lymphoma (ARL) was evaluated. A retrospective analysis of 73 HIV-1-infected patients with proven ARL diagnosed between 1992 and 2000 was conducted. Patients received uniformly the same chemotherapy regimen according to CD4 cell counts at NHL diagnosis:, patients with CD4 cells below or above 100 cells x 10(6)/liter received CHOP or ACVBP regimens, respectively. Event-free survival (EFS) and survival were estimated by the Kaplan-Meir method and a Cox model was used to evaluate the effect of different variables on survival. At diagnosis of ARL, the median age was 37 years and 22 patients (30%) had prior AIDS-defining events. Median CD4 cell count was 99 x 10(6)/liter. The median follow-up was 60 months. Ann Arbor stage 3-4 was noted in 60 patients (82%) and bone marrow or meningeal involvement was present in 13 (17%) and 12 (16%) patients, respectively. Two groups were identified: group 1 (n = 38) included patients who had never received HAART and group 2 (n = 35) included those who received HAART either before the diagnosis or following ARL. There was no statistical significant differences in lymphoma extensive stage, presence of B symptoms, meningeal involvement, CD4 cell count at diagnosis, prior AIDS events, or chemotherapy regimens between the two groups. Median survival (MS) of the whole cohort of patients was 8 months. Estimated EFS was significantly higher (30 months) in group 2 compared to group 1 (6.1 months) (p = 0.03). In the multivariate Cox model HAART has an independent significant effect on EFS (p = 0.0085). No influence on outcome was found for other variables except for prior AIDS and bone marrow involvement. HAART has significantly improved the survival and EFS in patients with ARL, independently of chemotherapy regimen.
Assuntos
Terapia Antirretroviral de Alta Atividade , Linfoma Relacionado a AIDS/mortalidade , Adulto , Contagem de Linfócito CD4 , Feminino , Humanos , Linfoma Relacionado a AIDS/imunologia , Masculino , Prognóstico , Estudos RetrospectivosRESUMO
BACKGROUND: Buprenorphine was approved in France for treating opiate dependence in July 1995 and can be prescribed by general practitioners (GPs). Most studies assessing buprenorphine maintenance treatment (BMT) outcomes have taken place in GP settings. An evaluation of BMT outcomes in patients already followed for their HIV-infection could supply additional information about the changes in addictive practices in a non-GP setting. METHODS: We assessed BMT discontinuations and the course of self-reported addictive behaviours and characteristics associated with buprenorphine-injection misuse in 114 HIV-infected patients on BMT who were followed in a hospital-based outpatient department. RESULTS: The continuous series of follow-up visits at which these 114 patients reported regular buprenorphine prescriptions accounted for 237.5 person-years of observation, i.e. 475 follow-up visits. Of the 114 patients on BMT, 43% continued BMT throughout the follow-up, 40% stopped it, and results for 17% were not available either because they did not answer the self-administered questionnaire (5%) or because they were lost to follow-up (12%). Addictive behaviours declined but buprenorphine injection misuse remained stable. Depression measured by the CESD score (RR=1.04 95%CI [1.01-1.06]), cocaine use (RR=2.48 95%CI [1.31-4.68]) and alcohol consumption exceeding 4 alcohol units (AU) per day (RR=2.29, 95%CI [1.17-4.46]) were independently associated with buprenorphine injection misuse among stabilised BMT patients. CONCLUSIONS: Despite the reduction in drug injection after starting BMT, buprenorphine injection misuse mainly involves patients with characteristics of severe addiction. Better monitoring of the illicit drug use patterns of patients on BMT may suggest new medical strategies for GPs to improve BMT outcomes.
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Buprenorfina/uso terapêutico , Transtornos Relacionados ao Uso de Cocaína/tratamento farmacológico , Soropositividade para HIV/complicações , Dependência de Heroína/tratamento farmacológico , Antagonistas de Entorpecentes/uso terapêutico , Abuso de Substâncias por Via Intravenosa/diagnóstico , Recusa do Paciente ao Tratamento/estatística & dados numéricos , Adulto , Buprenorfina/administração & dosagem , Estudos de Coortes , Depressão/diagnóstico , Depressão/etiologia , Feminino , Seguimentos , Soropositividade para HIV/psicologia , Humanos , Injeções Intravenosas , Masculino , Índice de Gravidade de Doença , Abuso de Substâncias por Via Intravenosa/epidemiologia , Inquéritos e QuestionáriosRESUMO
Stathmin family proteins interact with tubulin and negatively regulate its assembly in microtubules. One stathmin molecule forms a complex with two alphabeta tubulin heterodimers in an interaction that is weakened upon stathmin phosphorylation. The X-ray structure of crystals of the complex reveals a head-to-tail arrangement of the two tubulins which are connected by a long stathmin alpha helix. By holding tubulins in a curved complex that is not incorporated in microtubules, stathmin lowers the pool of "assembly competent" tubulin. An alternate mechanism has been also proposed to account for the stathmin action in vivo; it involves a direct interaction of stathmin with microtubule (+) ends. More experiments are needed to evaluate the relative contribution of this alternative mechanism to the regulation of tubulin assembly by stathmin.
Assuntos
Proteínas dos Microtúbulos , Microtúbulos/química , Fosfoproteínas/metabolismo , Tubulina (Proteína)/metabolismo , Dimerização , Microtúbulos/ultraestrutura , Modelos Moleculares , Fosforilação , Estrutura Secundária de Proteína , EstatminaRESUMO
The study, carried out in the French MANIF 2000 cohort of HIV positive patients contaminated through injecting drug use, assessed the impact of patients' sociodemographic and psychological characteristics, behaviors toward drug abuse, and antiretroviral treatment characteristics on the maintenance of adherence to HAART (highly active antiretroviral therapies). A total of 96 patients (30 men and 66 women), who were initially adherent at their first visit after HAART prescription, were considered for analysis. Among these 96 patients, 22 (22.9%) experienced adherence failure defined as a self-reported, non-adherence behavior at any visit before the 18th month of treatment. Logistic regression showed that lack of a stable relationship, active drug injection, and depression were independently associated with adherence failure. Patients' counseling for facilitating maintenance of adherence to HAART over time should focus on prevention of drug use, provision of social support and consider the potential impact of difficulties with treatment on psychological well-being.
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Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , Cooperação do Paciente , Adulto , Estudos de Coortes , Aconselhamento , Feminino , França , Infecções por HIV/psicologia , Humanos , Masculino , Assunção de Riscos , Apoio Social , Abuso de Substâncias por Via IntravenosaRESUMO
In a sample of 277 patients included in the French APROCO cohort study who were initially adherent at follow-up visit 4 months after initiation of a protease inhibitor-containing regimen, 76.4% self-reported at least one lipodystrophy-related symptom and 30.0% failed to maintain adherence behaviour 20 months after enrolment. After multiple adjustment for other related factors, such as younger age, alcohol consumption and poor housing conditions, the number of self-reported lipodystrophy symptoms was independently associated with adherence failure.
Assuntos
Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , Lipodistrofia/induzido quimicamente , Cooperação do Paciente , Adulto , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Fatores de TempoRESUMO
PURPOSE: To describe the clinical features in HIV-1-infected patients treated with protease inhibitors (PIs) or not, and to determine factors related to occurrence of lipodystrophy (LD). METHOD: We performed a cross-sectional analysis of 685 treated HIV-1-infected patients that were routinely followed in 6 Paris hospital centers between January and May 1999. Demographic data, familial and personal vascular risk factors, history of antiretroviral treatment, HIV plasma viral load, CD4 cell count, and metabolic data were collected. Clinical examination was based on an assessment of changes in abdominal, dorso-cervical, and breast girth and wasting of the limbs, face, and skin as quoted by the clinician. RESULTS: The mean age at inclusion in the study was 38 years; 29.5% were women. At study assessment, 77.5% of patients were PI-treated and 22.5% had never received a PI. LD was observed in 403 (58.8%) patients, of whom 340 were currently receiving a PI and 63 had never received a PI. More than half of the lipodystrophic patients had a mixed form (53.9%), while 25.3% were classified as exclusive lipoatrophic and 20.8% as exclusive hypertrophic. In multivariate analysis, older age, duration of antiretroviral treatment (ART), antiretroviral combinations including stavudine, antiretroviral combinations including a PI, AIDS status, and a low HIV RNA were independently associated with occurrence of LD. CONCLUSION: LD is frequently observed in PI-treated patients, but it is also observed in patients receiving an ART regimen without PIs. Our study suggests different underlying mechanisms, because immunovirological response to treatment as well as certain therapies were linked to the occurrence of LD. This hypothesis would be best clarified in a large prospective cohort of naive patients.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Infecções por HIV/tratamento farmacológico , Lipodistrofia/induzido quimicamente , Lipodistrofia/epidemiologia , Inibidores da Transcriptase Reversa/efeitos adversos , Adulto , Estudos Transversais , Quimioterapia Combinada , Feminino , HIV-1/isolamento & purificação , Humanos , Masculino , RNA Viral/sangue , Fatores de RiscoRESUMO
OBJECTIVE: To provide descriptive and outcome information of an outpatient pediatric psychology clinic based in a medical center in a major metropolitan area. METHODS: We coded the characteristics and outcomes of 100 patients prospectively on a number of dimensions. Surveys and interviews were used to gather follow-up information. RESULTS: The majority of patients were Caucasian boys (n = 56 out of 100) between 2 and 12 years of age. The most common reasons for initiating contact with the clinic were assessment of school problems, behavior problems, anger, attention problems, depression, and temper tantrums. Eighty-one percent of the patients saw a therapist for brief treatment, between one and five sessions, and behavioral treatments were administered for the majority. The children's behavior for which the parents sought treatment improved significantly from pre- to posttreatment, as rated by parents and therapists. CONCLUSIONS: Overall, parents were satisfied with the services received and indicated that the recommendations given during therapy were helpful and easy to implement. This study provides general evidence for the effectiveness of pediatric psychology services.
Assuntos
Transtornos do Comportamento Infantil/terapia , Serviços de Saúde da Criança/normas , Serviços de Saúde Mental/normas , Psicologia da Criança/normas , Adolescente , Adulto , Criança , Serviços de Saúde da Criança/estatística & dados numéricos , Pré-Escolar , Comportamento Cooperativo , Humanos , Lactente , Masculino , Serviços de Saúde Mental/estatística & dados numéricos , Meio-Oeste dos Estados Unidos , Ambulatório Hospitalar/normas , Atenção Primária à Saúde/normas , Estudos Prospectivos , Encaminhamento e Consulta , Resultado do TratamentoRESUMO
Death rates in the APROCO cohort of 1,157 HIV-1 infected adults starting for the first time a protease inhibitor-containing therapy were standardized to the 1996 French general population mortality rates stratified by age and gender. Median follow-up was 23 months and mortality rate was 2.2% person-years (95% confidence interval [CI] = 1.6-2.9). Overall mortality was 7.8 times higher than in the general population (95% CI = 5.7-10.4), 4.7 in men and 19.5 in women. Among the 144 patients considered complete responders, the death rate was 1.2% person-years (95% CI = 0.2-3.5) and mortality remained 5.1 times higher (95% CI = 1.0-14.9) than in the general population. Failure of treatment, long-term adverse effects, or less favorable socio-demographic status could explain these trends.
Assuntos
Infecções por HIV/tratamento farmacológico , Infecções por HIV/mortalidade , Inibidores da Protease de HIV/uso terapêutico , HIV-1 , Adulto , Distribuição por Idade , Fármacos Anti-HIV/uso terapêutico , Estudos de Coortes , Quimioterapia Combinada , Feminino , Humanos , Masculino , Mortalidade , Estudos Prospectivos , Inibidores da Transcriptase Reversa/uso terapêutico , Distribuição por SexoRESUMO
Rapid and effective medical intervention in response to civil and military-related disasters is crucial for saving lives and limiting long-term disability. Inexperienced providers may suffer in performance when faced with limited supplies and the demands of stabilizing casualties not generally encountered in the comparatively resource-rich hospital setting. Head trauma and multiple injury cases are particularly complex to diagnose and treat, requiring the integration and processing of complex multimodal data. In this project, collaborators adapted and merged existing technologies to produce a flexible, modular patient simulation system with both three-dimensional virtual reality and two-dimensional flat screen user interfaces for teaching cognitive assessment and treatment skills. This experiential, problem-based training approach engages the user in a stress-filled, high fidelity world, providing multiple learning opportunities within a compressed period of time and without risk. The system simulates both the dynamic state of the patient and the results of user intervention, enabling trainees to watch the virtual patient deteriorate or stabilize as a result of their decision-making speed and accuracy. Systems can be deployed to the field enabling trainees to practice repeatedly until their skills are mastered and to maintain those skills once acquired. This paper describes the technologies and the process used to develop the trainers, the clinical algorithms, and the incorporation of teaching points. We also characterize aspects of the actual simulation exercise through the lens of the trainee.
Assuntos
Instrução por Computador/métodos , Educação Médica Continuada/métodos , Auxiliares de Emergência/educação , Medicina de Emergência/educação , Tratamento de Emergência/métodos , Militares/educação , Medicina Naval/educação , Simulação de Paciente , Ensino/métodos , Interface Usuário-Computador , Algoritmos , Atitude do Pessoal de Saúde , Competência Clínica , Gráficos por Computador , Tomada de Decisões , Auxiliares de Emergência/psicologia , Humanos , Militares/psicologia , Aprendizagem Baseada em Problemas/métodos , Fatores de TempoRESUMO
Stathmin/Op18 destabilizes microtubules in vitro and regulates microtubule polymerization in vivo. Both a microtubule catastrophe-promoting activity and a tubulin sequestering activity were demonstrated for stathmin in vitro, and both could contribute to microtubule depolymerization in vivo. Stathmin activity can be turned down by extensive phosphorylation on its four phosphorylatable serines, and down-regulation of stathmin activity by phosphorylation is necessary for cells to proceed through mitosis. We show here that microinjection of a nonphosphorylatable Ser to Ala (4A) quadruple mutant in Xenopus two-cell stage embryos results in cell cleavage arrest in the injected blastomeres and aborted development, whereas injection of a pseudo-phosphorylated Ser to Glu quadruple mutant (4E) does not prevent normal development. Addition of these mutants to mitotic cytostatic factor-arrested extracts in which spindle assembly was induced led to a dramatic reduction of spindle size with 4A stathmin, and to a moderate increase with 4E stathmin, but both localized to spindle poles. Interestingly, the microtubule assembly-dependent phosphorylation of endogenous stathmin was abolished in the presence of 4A stathmin, but not of 4E stathmin. Altogether, this shows that the phosphorylation-mediated regulation of stathmin activity during the cell cycle is essential for early Xenopus embryonic development.
Assuntos
Desenvolvimento Embrionário , Proteínas dos Microtúbulos , Mutação , Fosfoproteínas/metabolismo , Animais , Embrião não Mamífero/metabolismo , Humanos , Microscopia de Fluorescência , Fosfoproteínas/genética , Fosforilação , Estatmina , Xenopus/embriologia , Proteínas de XenopusRESUMO
Stathmin family phosphoproteins (stathmin, SCG10, SCLIP, and RB3/RB3'/RB3") are involved in signal transduction and regulation of microtubule dynamics. With the exception of stathmin, they are expressed exclusively in the nervous system, where they display different spatio-temporal and functional regulations and hence play at least partially distinct and possibly complementary roles in relation to the control of development, plasticity, and neuronal activities. At the molecular level, each possesses a specific "stathmin-like domain" and, with the exception of stathmin, various combinations of N-terminal extensions involved in their association with intracellular membrane compartments. We show here that each stathmin-like domain also displays specific biochemical and tubulin interaction properties. They are all able to sequester two alpha/beta tubulin heterodimers as revealed by their inhibitory action on tubulin polymerization and by gel filtration. However, they differ in the stabilities of the complexes formed as well as in their interaction kinetics with tubulin followed by surface plasmon resonance as follows: strong stability and slow kinetics for RB3; medium for SCG10, SCLIP, and stathmin; and weak stability and rapid kinetics for RB3'. These results suggest that the fine-tuning of their stathmin-like domains contributes to the specific functional roles of stathmin family proteins in the regulation of microtubule dynamics within the various cell types and subcellular compartments of the developing or mature nervous system.
Assuntos
Proteínas dos Microtúbulos , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Tubulina (Proteína)/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Proteínas de Ligação ao Cálcio , Proteínas de Transporte , Peptídeos e Proteínas de Sinalização Intracelular , Cinética , Proteínas de Membrana , Camundongos , Dados de Sequência Molecular , Fatores de Crescimento Neural/química , Fatores de Crescimento Neural/metabolismo , Estrutura Secundária de Proteína , Ratos , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Estatmina , Ressonância de Plasmônio de SuperfícieRESUMO
Stathmin/Op 18 is a microtubule (MT) dynamics-regulating protein that has been shown to have both catastrophe-promoting and tubulin-sequestering activities. The level of stathmin/Op18 phosphorylation was proved both in vitro and in vivo to be important in modulating its MT-destabilizing activity. To understand the in vivo regulation of stathmin/Op18 activity, we investigated whether MT assembly itself could control phosphorylation of stathmin/Op18 and thus its MT-destabilizing activity. We found that MT nucleation by centrosomes from Xenopus sperm or somatic cells and MT assembly promoted by dimethyl sulfoxide or paclitaxel induced stathmin/Op18 hyperphosphorylation in Xenopus egg extracts, leading to new stathmin/Op18 isoforms phosphorylated on Ser 16. The MT-dependent phosphorylation of stathmin/Op18 took place in interphase extracts as well, and was also observed in somatic cells. We show that the MT-dependent phosphorylation of stathmin/Op18 on Ser 16 is mediated by an activity associated to the MTs, and that it is responsible for the stathmin/Op18 hyperphosphorylation reported to be induced by the addition of "mitotic chromatin." Our results suggest the existence of a positive feedback loop, which could represent a novel mechanism contributing to MT network control.
Assuntos
Proteínas dos Microtúbulos , Microtúbulos/metabolismo , Fosfoproteínas/metabolismo , Animais , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Centrossomo/metabolismo , Inibidores Enzimáticos/farmacologia , Feminino , Células HeLa , Humanos , Interfase/fisiologia , Masculino , Microtúbulos/efeitos dos fármacos , Nocodazol/farmacologia , Óvulo/metabolismo , Óvulo/ultraestrutura , Paclitaxel/farmacologia , Fosforilação , Isoformas de Proteínas , Serina/metabolismo , Espermatozoides/metabolismo , Espermatozoides/ultraestrutura , Estatmina , Xenopus , Proteínas de XenopusRESUMO
Stathmin and SCG10 belong to a family of phosphoproteins associated to cell proliferation and differentiation. In the present study, we have analyzed immunocytochemically the distribution of these proteins during neurogenesis in the mouse olfactory system, from midgestation to adulthood. Data show that already at embryonic day 12, stathmin and SCG10 immunoreactivities were present in the olfactory and vomeronasal neurons, and their number increased greatly, colocalizing with neuronal specific tubulin, a marker of immature neurons. Later on up to adulthood, the distribution of stathmin and SCG10 became progressively restricted to a few immature receptor and chemosensory neurons. Significantly, in the olfactory epithelium, stathmin was seen in immature neurons and also in basal cells representing precursors of neuronal elements. Interestingly, before birth stathmin and SCG10 immunopositive cells were seen outside the olfactory epithelium, seemingly migrating toward the olfactory bulb. After regeneration in the adult following peripheral lesion of the olfactory epithelium, stathmin and SCG10 were again strongly expressed and generally colocalized with neuronal specific tubulin immunoreactivity. Overall these results indicate that stathmin and SCG10 are expressed in immature olfactory neurons as well as in the migrating cells generated from the olfactory epithelium, supporting the role of these proteins in neurogenesis and cell migration.
Assuntos
Proteínas dos Microtúbulos , Fatores de Crescimento Neural/biossíntese , Mucosa Olfatória/metabolismo , Neurônios Receptores Olfatórios/citologia , Fosfoproteínas/biossíntese , Animais , Proteínas de Ligação ao Cálcio , Denervação , Feminino , Feto/citologia , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Camundongos Endogâmicos , Fatores de Crescimento Neural/análise , Regeneração Nervosa/fisiologia , Proteínas do Tecido Nervoso/análise , Proteína de Marcador Olfatório , Mucosa Olfatória/citologia , Mucosa Olfatória/crescimento & desenvolvimento , Neurônios Receptores Olfatórios/química , Neurônios Receptores Olfatórios/metabolismo , Fosfoproteínas/análise , Gravidez , Estatmina , Tubulina (Proteína)/análiseRESUMO
We have identified a rapid protein phosphorylation event at residue serine 16 of stathmin using two-dimensional gel electrophoresis coupled to matrix-assisted laser desorption/ionization mass spectrometry in combination with post-source decay analysis, which is induced by the epidermal growth factor receptor. Phosphorylation is specifically mediated by the small GTPases Rac and Cdc42 and their common downstream target, the serine/threonine kinase p65PAK. Both GTPases have previously been shown to regulate the dynamics of actin polymerization. Because stathmin destabilizes microtubules, and this process is inhibited by phosphorylation at residue 16, Rac and Cdc42 can potentially regulate both F-actin and microtubule dynamics.
Assuntos
Proteínas dos Microtúbulos , Microtúbulos/metabolismo , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Serina/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Linhagem Celular , Fosfoproteínas/química , Fosforilação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Estatmina , Quinases Ativadas por p21RESUMO
The fastest growing population of children in foster care today is quite young, and many of these children have significant health care needs. The General Accounting Office (GAO) reported that children in foster care "are among the most vulnerable individuals in the welfare population" (GAO, 1995, p. 1). Poverty, increased homelessness, substance abuse, and a rise in the incidence of persons with HIV all contribute to the problems faced by these children. The Caring Communities for Children in Foster Care Project, funded by the Maternal Child Health Bureau Integrated Services Medical Home Initiative with the American Academy of Pediatrics (AAP), investigated the availability of comprehensive health care services for children in foster care. The AAP recommends that pediatricians serve as the primary health care provider for children in foster care and also as consultants to child welfare agencies. Pediatric nurses play a crucial role in providing health care services to children in foster care. With an increased understanding of the potential physical and mental health care needs of children in foster care and the important role of foster parents, pediatric nurses can increase the likelihood of positive health outcomes for children in foster care.
Assuntos
Proteção da Criança , Cuidados no Lar de Adoção , Adulto , Criança , Humanos , Poder Familiar , Relações Profissional-FamíliaRESUMO
Phosphoproteins of the stathmin family interact with the alphabeta tubulin heterodimer (tubulin) and hence interfere with microtubule dynamics. The structure of the complex of GDP-tubulin with the stathmin-like domain of the neural protein RB3 reveals a head-to-tail assembly of two tubulins with a 91-residue RB3 alpha helix in which each copy of an internal duplicated sequence interacts with a different tubulin. As a result of the relative orientations adopted by tubulins and by their alpha and beta subunits, the tubulin:RB3 complex forms a curved structure. The RB3 helix thus most likely prevents incorporation of tubulin into microtubules by holding it in an assembly with a curvature very similar to that of the depolymerization products of microtubules.