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1.
J Neurophysiol ; 127(1): 27-37, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34851768

RESUMO

Although there is evidence that 5-HT acts as an excitatory neuromodulator to enhance maximal force generation, it is largely unknown how 5-HT activity influences the ability to sustain a constant force during steady-state contractions. A total of 22 healthy individuals participated in the study, where elbow flexion force was assessed during brief isometric contractions at 10% maximal voluntary contraction (MVC), 60% MVC, MVC, and during a sustained MVC. The selective serotonin reuptake inhibitor, paroxetine, suppressed physiological tremor and increased force steadiness when performing the isometric contractions. In particular, a main effect of drug was detected for peak power of force within the 8-12 Hz range (P = 0.004) and the coefficient of variation (CV) of force (P < 0.001). A second experiment was performed where intermittent isometric elbow flexions (20% MVC sustained for 2 min) were repeatedly performed so that serotonergic effects on physiological tremor and force steadiness could be assessed during the development of fatigue. Main effects of drug were once again detected for peak power of force in the 8-12 Hz range (P = 0.002) and CV of force (P = 0.003), where paroxetine suppressed physiological tremor and increased force steadiness when the elbow flexors were fatigued. The findings of this study suggest that enhanced availability of 5-HT in humans has a profound influence of maintaining constant force during steady-state contractions. The action of 5-HT appears to suppress fluctuations in force regardless of the fatigue state of the muscle.NEW & NOTEWORTHY Converging lines of research indicate that enhanced serotonin availability increases maximal force generation. However, it is largely unknown how serotonin influences the ability to sustain a constant force. We performed two experiments to assess physiological tremor and force steadiness in unfatigued and fatigued muscle when serotonin availability was enhanced in the central nervous system. Enhanced availability of serotonin reduced physiological tremor amplitude and improved steadiness regardless of muscle fatigue.


Assuntos
Fenômenos Biomecânicos/efeitos dos fármacos , Contração Isométrica/efeitos dos fármacos , Fadiga Muscular/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Paroxetina/farmacologia , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Serotonina/metabolismo , Tremor/tratamento farmacológico , Adulto , Cotovelo/fisiologia , Humanos , Masculino , Paroxetina/administração & dosagem , Inibidores Seletivos de Recaptação de Serotonina/administração & dosagem , Adulto Jovem
2.
J Public Health (Oxf) ; 43(3): 647-654, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32323719

RESUMO

BACKGROUND: Children's second-hand smoke (SHS) exposure in the home is highest in socio-economically disadvantaged areas. Personalized household air-quality measurements can promote changes in smoking that reduce SHS exposure. The 'First Steps 2 Smoke-free' (FS2SF) intervention is the first to trial this approach delivered as part of health professionals' routine work. This paper reports the findings of qualitative interviews with participants that explored their experiences of the intervention and why outcomes varied. METHODS: 120 women were recruited from the NHS First Steps Programme, which supports disadvantaged mothers. They received either personalized feedback on their home air quality and advice on reducing SHS or standard SHS advice. Qualitative interviews with 15 mothers were analyzed thematically using the Capability, Opportunity, Motivation, Behaviour (COM-B) model. RESULTS: The intervention increased women's capability to change home-smoking behaviour, through increasing awareness and salience of SHS risks to their children, and motivation to act. However, taking effective action was constrained by their limited social and environmental opportunities, including others' smoking in the home. CONCLUSIONS: The FS2SF intervention was ineffective as it was unable to fully address the precarious, complex life circumstances that make creating a smoke-free home particularly difficult for women experiencing intersecting dimensions of disadvantage.


Assuntos
Poluição do Ar , Poluição por Fumaça de Tabaco , Criança , Exposição Ambiental/análise , Feminino , Humanos , Mães , Motivação , Populações Vulneráveis
3.
BMC Immunol ; 21(1): 47, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778048

RESUMO

BACKGROUND: Subcutaneous immunoglobulin (SCIG) is increasingly utilized in primary immunodeficiency (PI). Understanding factors associated with treatment experience and satisfaction can optimize patient outcomes. We analyzed Immune Deficiency Foundation (IDF) survey data to evaluate patient-reported outcomes (PROs) in relation to SCIG training and infusion characteristics. Respondents' PRO scores were rank ordered into 'best', 'intermediate', and 'worst' tertiles. Predicted probabilities of being in the best tertile with any combination of characteristics were generated for each PRO. RESULTS: In 366 SCIG respondents, higher odds of being in the best PRO tertile were driven by favorable training characteristics (particularly, higher confidence post-training and no training barriers) and efficient infusions (infusion preparation ≤20 min and actual infusion < 2 h). Age (≤17 years old) and treatment experience (> 2 years) increased the odds of being in the best tertiles. Compared with the least favorable training/infusion characteristics, those with the most favorable training/infusion characteristics had higher predicted probabilities of being in the best tertiles: TSQM side effects, 59% vs 4%; convenience, 52% vs 4%; effectiveness, 27% vs 13%; global, 26% vs 3%; PROMIS Fatigue, 44% vs 18%. CONCLUSIONS: Increased experience with SCIG consistently improved PROs, but our findings predicted that enhanced training and infusion characteristics improve patient treatment satisfaction beyond that achieved by experience alone.


Assuntos
Imunoglobulinas/uso terapêutico , Doenças da Imunodeficiência Primária/imunologia , Ensino/estatística & dados numéricos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Fadiga/etiologia , Feminino , Humanos , Imunoglobulinas/genética , Infusões Subcutâneas , Masculino , Medidas de Resultados Relatados pelo Paciente , Satisfação do Paciente , Qualidade de Vida , Estudos Retrospectivos , Inquéritos e Questionários , Resultado do Tratamento
4.
Epidemiol Infect ; 144(15): 3316-3325, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27488877

RESUMO

This study was conducted to examine the incidence trend of campylobacteriosis in Michigan over a 10-year period and to investigate risk factors and clinical outcomes associated with infection. Campylobacter case data from 2004 to 2013 was obtained from the Michigan Disease Surveillance System. We conducted statistical and spatial analyses to examine trends and identify factors linked to campylobacteriosis as well as ecological associations using animal density data from the National Agricultural Statistics Service. An increasing trend of Campylobacter incidence and hospitalization was observed, which was linked to specific age groups and rural residence. Cases reporting ruminant contact and well water as the primary drinking source had a higher risk of campylobacteriosis, while higher cattle density was associated with an increased risk at the county level. Additional studies are needed to identify age-specific risk factors and examine prevalence and transmission dynamics in ruminants and the environment to aid in the development of more effective preventive strategies.


Assuntos
Infecções por Campylobacter/epidemiologia , Campylobacter/fisiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Infecções por Campylobacter/microbiologia , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Michigan/epidemiologia , Pessoa de Meia-Idade , Fatores de Risco , População Rural , Adulto Jovem
5.
Epidemiol Infect ; 144(7): 1394-405, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26584572

RESUMO

Infection with Shiga toxin-producing Escherichia coli (STEC) by serotypes other than O157 (non-O157) have been increasingly reported in the United States. This increase in reporting is primarily due to the improvements in diagnostic tests. We analysed 1497 STEC cases reported in Michigan from 2001 to 2012. A significant increase in the number of non-O157 STEC cases was observed over time, and similar incidence rates were observed for O157 and non-O157 STEC cases in certain time periods. The odds of hospitalization was two times higher in O157 STEC cases relative to non-O157 STEC cases when adjusted for age and gender, suggesting that O157 STEC causes more severe clinical outcomes in all age groups. The use of population-based surveillance to better define trends and associations with disease severity are critical to enhance our understanding of STEC infections and improve upon current prevention and control efforts.


Assuntos
Infecções por Escherichia coli/epidemiologia , Síndrome Hemolítico-Urêmica/epidemiologia , Escherichia coli Shiga Toxigênica/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Infecções por Escherichia coli/microbiologia , Feminino , Síndrome Hemolítico-Urêmica/microbiologia , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Michigan/epidemiologia , Pessoa de Meia-Idade , Adulto Jovem
6.
Curr Oncol ; 22(5): e357-63, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26628876

RESUMO

BACKGROUND: Keratoconjunctivitis sicca from chronic graft-versus-host disease (cgvhd) after allogeneic stem cell transplantation is common, leading to severe corneal damage and blindness if not treated. We retrospectively examined the efficacy and safety of pooled human albumin eye drops (haeds) for symptom relief in 40 stem-cell transplantation patients after other alternatives had failed. METHODS: The Common Terminology Criteria for Adverse Events (version 4.0) and the cgvhd grading scale were used to compare response in the patients during January 2000 and July 2013. In addition, on days 1 and 30, the haeds were subjected to quality assurance testing for sterility, oncotic pressure, albumin measurement, viscosity, pH, and purity by protein electrophoresis. RESULTS: Use of haeds resulted in symptom relief for 37 patients (92.5%); 3 patients (7.5%) failed to improve with use of haeds (p ≤ 0.0001). Of the 37 patients having symptom relief, 7 (19%) improved from grade 3 to no dry eye symptoms. Proportionately, post-treatment symptom improvement by two grade levels, from 3 to 1 (70%), was significantly higher than improvement by one grade level, from 3 to 2 (11%) or from 2 to 1 (19%, p ≤ 0.0001). Time to symptom relief ranged from 2 weeks to 28 weeks. Of the 40 patients, 38 (95%) had no adverse reactions. Days 1 and 30 quality assurance testing results were equivalent. CONCLUSIONS: Complications of keratoconjunctivitis sicca were well managed and well tolerated with haeds when other remedies failed. Quality assurance testing confirmed that haeds were safe and stable in extreme conditions.

7.
Rev Sci Instrum ; 95(10)2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39352237

RESUMO

The SPARC tokamak will have scrape-off layer parallel heat fluxes on the order of GW/m2. Managing power exhaust of this magnitude will be mandatory for a reactor-scale device. To enable this mission, a thermal diagnostic suite will be deployed to measure the in-vessel structural temperatures to ensure they do not exceed their design limits and to determine the spatial distribution and magnitude of energy deposited onto the first wall. Thermocouples and fiber Bragg gratings have been selected for their environmental compatibility and proven useful on other fusion devices. High-density thermocouple arrays in the divertor will have two spring-loaded thermocouples per divertor target tile, which are being used as calorimeters, and will look to resolve the temperature distribution within the tile due to a swept or static strike point. All systems will need to survive the vacuum vessel bake, set at a minimum plasma facing surface temperature of 350 °C, which presents a particularly challenging environment for the fiber-based subsystem. Along with this temperature design requirement, all the materials in the primary vacuum need to be ultra-high vacuum compatible, able to handle the expected neutron and gamma radiation, as well as tritium exposure, all of which restrict material options. Finally, due to the expected activated environment in SPARC, there will be little chance to replace defective sensors, so system resilience is ensured through toroidal redundancy, probe material selection, and mitigating the impact of common-mode failures. Initial testing of sensors show that intershot structural measurements are sufficiently captured with the raw output, but intrashot measurements of the plasma facing material requires model-based interpretive tools.

8.
Clin Biochem ; 120: 110644, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37673294

RESUMO

OBJECTIVES: Prominent physiological changes occurring throughout childhood and adolescence necessitate the consideration of age and sex in biomarker interpretation. Critical gaps exist in pediatric reference intervals (RIs) for specialized endocrine markers, despite expected influence of growth and development. The current study aimed to establish and/or verify RIs for six specialized endocrine markers on a specialized immunoassay system. METHODS: Samples were collected from healthy children and adolescents (5 to <19 years) and apparently healthy outpatients (0 to <5 years) as part of the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER). Serum samples were analysed for aldosterone, renin (plasma), thyroglobulin, anti-thyroglobulin, growth hormone, and insulin-like growth factor-1 (IGF-1) on the Liaison XL (DiaSorin) immunoassay platform. RIs (2.5th and 97.5th percentiles) were established for aldosterone, renin, thyroglobulin, anti-thyroglobulin, and growth hormone. Manufacturer-recommended pediatric RIs for IGF-1 were verified. RESULTS: Age-specific RIs were established for aldosterone, renin, and thyroglobulin, while no age-specific differences were observed for anti-thyroglobulin or growth hormone. IGF-1 was the only endocrine marker studied that demonstrated significant sex-specific differences. Manufacturer-recommended IGF-1 RIs were verified for children aged 6 to <19 years, while those for children aged 0 to <6 years did not verify. CONCLUSIONS: This study marks the first time that pediatric RIs for aldosterone and renin were established in the CALIPER cohort and highlights the dynamic changes that occur in water and sodium homeostasis during the first years of life. Overall, these data will assist pediatric clinical laboratories in test result interpretation and improve clinical decision-making for patients tested using Liaison immunoassays.


Assuntos
Fator de Crescimento Insulin-Like I , Tireoglobulina , Masculino , Feminino , Criança , Humanos , Adolescente , Aldosterona , Renina , Valores de Referência , Imunoensaio , Hormônio do Crescimento
9.
Clin Exp Allergy ; 42(12): 1734-44, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23181789

RESUMO

BACKGROUND: The mechanisms by which viruses induce asthma exacerbations are not well understood. OBJECTIVE: We characterized fluctuations in nasal aspirate cytokines during naturally occurring respiratory viral infections in children with asthma. METHODS: Sixteen children underwent home collections of nasal aspirates when they were without cold symptoms and again during self-reported respiratory illnesses. The presence of viral infection was ascertained by multiplex PCR. Cytokines were measured using multiplex immune assay. mRNA expression for selected markers of viral infection was measured using RT-PCR. A cumulative respiratory symptom score was calculated for each day of measurement. Generalized estimated equations were used to evaluate associations between viral infection and marker elevation, and between marker elevation and symptom score. RESULTS: The 16 patients completed a total of 37 weeks of assessment (15 'well' weeks; 22 self-assessed 'sick' weeks). Viral infections were detected in 3 of the 'well' weeks and 17 of the 'sick' weeks (10 rhinovirus, three coronavirus, two influenza A, two influenza B, two respiratory syncytial virus, one parainfluenza). Compared to virus-negative well weeks, nasal aspirate IFN-γ, CXCL8/IL-8, CXCL10/IP-10, CCL5/RANTES, CCL11/eotaxin-1, CCL2/MCP-1, CCL4/MIP-1ß, CCL7/MCP-3, and CCL20/MIP3α protein levels increased during virus-positive sick weeks. Only a subset of cytokines (IFN-γ, CXCL8, CCL2, CCL4, CCL5, and CCL20) correlated with self-reported respiratory tract symptoms. While many aspirates were dilute and showed no mRNA signal, viral infection significantly increased the number of samples that were positive for IFN-λ1, IFN-λ2/3, TLR3, RIG-I, and IRF7 mRNA. CONCLUSIONS AND CLINICAL RELEVANCE: We conclude that in children with asthma, naturally occurring viral infections apparently induce a robust innate immune response including expression of specific chemokines, IFNs, and IFN-responsive genes.


Assuntos
Asma , Citocinas/metabolismo , Cavidade Nasal/imunologia , Infecções Respiratórias/imunologia , Viroses/imunologia , Vírus/imunologia , Adolescente , Asma/imunologia , Asma/virologia , Quimiocinas/imunologia , Quimiocinas/metabolismo , Criança , Citocinas/genética , Citocinas/imunologia , Feminino , Humanos , Imunidade Inata , Interferons/imunologia , Interferons/metabolismo , Masculino , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/fisiopatologia , Infecções Respiratórias/virologia , Viroses/diagnóstico , Viroses/fisiopatologia , Viroses/virologia , Vírus/classificação , Vírus/genética , Vírus/isolamento & purificação
10.
Sci Rep ; 12(1): 12688, 2022 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-35879340

RESUMO

Native predators are increasingly exposed to habitat loss and fragmentation globally. When developing conservation and management strategies, it is important to determine whether fragmented landscapes can still support similar predator densities to intact areas, and thereby constitute important habitat for these species. The spotted-tailed quoll (Dasyurus maculatus) is an endangered Australian mesopredator that is often considered to be forest-dependent. While quolls are known to occur in some fragmented forest landscapes, it is unclear whether these areas represent sub-optimal habitat where quolls merely persist, or whether quolls can still occur at densities similar to those observed in intact forest landscapes. We used camera traps to detect quolls in both a fragmented and intact forested site, over three years. We used each quoll's unique pelage pattern to identify individual quolls and estimate population density at each site. We were able to assign more than 94% of quoll image sequences across both sites to identify 173 individuals during the study. Density estimates of 0.13-0.66 quolls per km2 at the fragmented site were comparable to estimates of 0.28-0.48 quolls per km2 at the intact site. Our results highlight the importance of retaining and protecting forest fragments for the conservation of endangered quoll populations.


Assuntos
Ecossistema , Marsupiais , Animais , Austrália , Humanos , Densidade Demográfica
11.
Perspect Public Health ; 141(2): 97-101, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33602030

RESUMO

AIMS: Outdoor play, physical activity, and social cohesion are crucial indicators of community health. PlayStreets, a street play initiative to engage local children and families in outdoor play, physical activity, and social interactions, were implemented in a low-income neighborhood in Columbus, Ohio throughout the summer of 2019. This article aims to describe the implementation of a hospital-sponsored PlayStreets model executed through support from a community health initiative and to assess neighborhood impact through parent and child surveys. METHODS: Approximately 350 children attended the events and 69 surveys were collected. Descriptive statistics were used to analyze survey data. RESULTS: The mean age of children was 7 years, and the majority of children who attended were male. If not for PlayStreets, 55% of caregivers reported that their children would be inside. Event satisfaction levels were high, and 54% of caregivers said that they had more contact with their neighbors because of the events. CONCLUSIONS: Hospital buy-in and community support were crucial to the success of the event. We found that this model can successfully engage the local community while increasing opportunity for childhood outdoor play, physical activity, and neighborhood social interaction.


Assuntos
Ambiente Construído , Exercício Físico , Características de Residência , Ambiente Construído/estatística & dados numéricos , Criança , Feminino , Humanos , Masculino , Ohio , Pais , Características de Residência/estatística & dados numéricos , Inquéritos e Questionários
12.
Neuropsychopharmacology ; 45(8): 1306-1315, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32268346

RESUMO

Adolescent alcohol exposure increases the risk of developing alcohol use disorders (AUDs), yet the mechanisms responsible for this vulnerability remain largely unknown. One potential target for alcohol-induced changes is the circuitry that modulates negative affect and stress, two sexually dependent drivers of alcohol relapse. The bed nucleus of the stria terminalis (BNST) is a sexually dimorphic region that critically regulates negative affective- and stress-induced relapse. Group I metabotropic glutamate receptors (mGluR) are a target of interest due to their regulation of stress, anxiety behaviors, and BNST plasticity. The current studies investigate sex-dependent sensitivity to the effects of adolescent intermittent ethanol vapor exposure (AIE) on negative affect during acute and protracted alcohol withdrawal and following stress in adulthood. This work also assessed whether BNST group I mGluR-mediated long-term depression (LTD) was disrupted at these timepoints. During acute withdrawal, AIE altered LTD induced by the group I mGluR antagonist DHPG in females, but not males. During adulthood, stress unmasked persistent changes in DHPG-induced LTD and behavior that were not present under basal conditions. Females with an AIE history demonstrated enhanced negative affective-like behavior in the novelty-induced hypophagia test following restraint stress-a phenotype that could be blocked with systemic mGluR5 allosteric antagonism via MTEP. Conversely, males with an AIE history demonstrated elevated freezing in a contextual fear conditioning paradigm. These studies demonstrate long-lasting, sex-dependent phenotypes produced by AIE and suggest pharmaceutical interventions for alcohol use and comorbid disorders may be more effective if designed with sex differences in mind.


Assuntos
Alcoolismo , Núcleos Septais , Adolescente , Adulto , Consumo de Bebidas Alcoólicas , Etanol , Feminino , Humanos , Masculino , Caracteres Sexuais
13.
Science ; 209(4462): 1245-7, 1980 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-17811198

RESUMO

In freshly laid egg masses of Helisoma sp., more than 95 percent of the phosphorus is found in alkylphosphonic acids, as determined by phosphorus-31 nuclear magnetic resonance spectroscopy. These compounds are metabolized during embryonic development, as shown by differential acid hydrolysis and experiments with phosphorus-33-labeled phosphoric acid. Further, nuclear magnetic resonance spectroscopy indicates phosphonic acid involvement in related snail families, including the schistosomal vector Biomphalaria glabrata.

14.
Science ; 169(3941): 192-4, 1970 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-4393300

RESUMO

Advanced methods of phosphorus-31 nuclear magnetic resonance spectroscopy provided a method whereby biological phosphonates and phosphates can be determined on simple lipid fractions of biological origin. The spectra consist of two easily distinguished resonance bands; one corresponds to families of phosphonates, and the other corresponds to families of orthophosphates.


Assuntos
Cnidários , Lipídeos/análise , Espectroscopia de Ressonância Magnética , Organofosfonatos/análise , Fosfatos/análise , Isótopos de Fósforo , Tetrahymena , Animais , Cyprinidae , Métodos
16.
Curr Biol ; 5(11): 1303-11, 1995 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-8574588

RESUMO

BACKGROUND: T cells and B cells communicate by direct cell--cell interaction that is crucial to the functioning of the immune system. It is well established that the interaction between B-cell-expressed CD40 and T-cell-expressed CD40 ligand (CD40L) is critical for T-cell-dependent antibody responses, but the role of this interaction in T-cell responses is less clear. In this study, we have used mice with targeted mutations in the genes encoding CD40L or CD28 to investigate how the CD40-CD40L interaction induces on B cells a costimulatory activity that acts in addition to antigen to trigger T-cell growth. RESULTS: We show that T cells from Cd40L-deficient mice induce a substantially reduced costimulatory activity on B cells compared to wild-type T cells, particularly at early time points. Surprisingly, T cells, from CD40L-deficient mice induce similar levels of B7-1 and B7-2 as do wild-type T cells. We further show that the CD40L-mediated induction of costimulatory activity precedes the induction of B7-1, B7-2 and the heat-stable antigen (HSA). CD4 T cells isolated from the CD28-deficient mice can receive costimulatory activity from CD40L-induced B cells, demonstrating that the induced molecules can costimulate T cells by a CD28-independent mechanism. We have generated a novel monoclonal antibody that inhibits the CD40L-induced costimulatory activity. Expression of the epitope detected by this monoclonal antibody correlates with the induction of the costimulatory activity, and the molecule recognized by the monoclonal antibody is a single chain of around 85 kDa, distinct from B7-1, B7-2, ICAM-1, ICAM-2, ICAM-3, HSA CD5, integrin and 4-1BB ligand. CONCLUSIONS: Our results demonstrate that CD40L is both necessary and sufficient for rapid, T-cell-mediated induction of costimulatory activity on B cells. This costimulatory activity is distinct from B7-1 and B7-2, and is independent of CD28.


Assuntos
Linfócitos B/metabolismo , Antígenos CD40/metabolismo , Glicoproteínas de Membrana/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Antígenos CD/metabolismo , Linfócitos B/imunologia , Antígeno B7-1/metabolismo , Antígeno B7-2 , Antígenos CD28/metabolismo , Linfócitos T CD4-Positivos/fisiologia , Antígenos CD40/genética , Ligante de CD40 , Divisão Celular , Linhagem Celular , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Mutagênese
17.
Nucleic Acids Res ; 29(17): 3583-94, 2001 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-11522828

RESUMO

A new algorithm called RNAMotif containing RNA structure and sequence constraints and a thermodynamic scoring system was used to search for intrinsic rho-independent terminators in the Escherichia coli K-12 genome. We identified all 135 reported terminators and 940 putative terminator sequences beginning no more than 60 nt away from the 3'-end of the annotated transcription units (TU). Putative and reported terminators with the scores above our chosen threshold were found for 37 of the 53 non-coding RNA TU and for almost 50% of the 2592 annotated protein-encoding TU, which correlates well with the number of TU expected to contain rho-independent terminators. We also identified 439 terminators that could function in a bi-directional fashion, servicing one gene on the positive strand and a different gene on the negative strand. Approximately 700 additional termination signals in non-coding regions (NCR) far away from the nearest annotated gene were predicted. This number correlates well with the excess number of predicted 'orphan' promoters in the NCR, and these promoters and terminators may be associated with as yet unidentified TU. The significant number of high scoring hits that occurred within the reading frame of annotated genes suggests that either an additional component of rho-independent terminators exists or that a suppressive mechanism to prevent unwanted termination remains to be discovered.


Assuntos
Escherichia coli/genética , Transcrição Gênica , Algoritmos , Sequência de Bases , Genoma Bacteriano , Conformação de Ácido Nucleico , RNA Bacteriano/química , RNA Bacteriano/genética , RNA Ribossômico/genética , RNA de Transferência/genética , Sequências Reguladoras de Ácido Nucleico/genética , Fator Rho/fisiologia
18.
Biochim Biophys Acta ; 491(2): 469-72, 1977 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-857904

RESUMO

The addition of 3 mM hemoglobin to 1-10 mM ATP solutions at pH 6.75 resulted in a linear relationship between the change in chemical shift (deltadelta) of the gamma-phosphate of ATP and the percent ATP bound to hemoglobin. The data points obtained with oxyhemoglobin and deoxyhemoglobin fell on the same straight line. In the presence of 3 mM Mg2+, the delta delta decreased curvilinearly as the percent ATP bound was raised. In this case, the percent ATP bound to deoxyhemoglobin was greater than to oxyhemoglobin at the same delta delta value, indicating that the extra ATP binding occurs through groups other than phosphate.


Assuntos
Trifosfato de Adenosina/sangue , Hemoglobinas , Magnésio/sangue , Sítios de Ligação , Humanos , Espectroscopia de Ressonância Magnética , Ligação Proteica , Conformação Proteica , Ultrafiltração
19.
Biochim Biophys Acta ; 427(2): 481-91, 1976 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-5126

RESUMO

1. The chemical shifts (delta) of the phosphates of 2,3-diphosphoglycerate and adenosine triphosphate (ATP) were determined by phosphorus nuclear magnetic resonance (31P NMR) spectroscopy and were found to be displaced downfield following the addition of hemoglobin (3 mM) to a solution of either diphosphoglycerate (5 mM) or ATP (1 mM). 2. The binding of these compounds to hemoglobin was also determined by membrane ultrafiltration. A direct relationship was observed between the change in chemical shift ((delta delta) of the 2-P and 3-P of diphosphoglycerate and the percent diphosphoglycerate bound, when the latter was varied by altering pH, oxygenation state, or total diphosphoglycerate concentration. 3. In comparable studies with ATP binding, a linear relationship between the delta delta values of the gamma-, beta-, and alpha-P of ATP and the percent of ATP bound was not observed when the data from all of the experiments were plotted. NMR signals were not detectible in deoxyhemoglobin solutions containing 1 mM ATP but were seen in solutions containing 3.8 mM ATP. 4. The results indicate that 31P NMR spectroscopy is a promising tool for investigating organic phosphate interactions with hemoglobin.


Assuntos
Trifosfato de Adenosina/sangue , Ácidos Difosfoglicéricos/sangue , Hemoglobinas , Sítios de Ligação , Humanos , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Oxiemoglobinas , Ligação Proteica , Conformação Proteica , Ultrafiltração
20.
Biochim Biophys Acta ; 490(2): 290-300, 1977 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-13855

RESUMO

Phosphorus nuclear magnetic resonance (31P NMR) spectroscopy was used to estimate the percent of 2,3-diphosphoglycerate and ATP bound to hemoglobin in intact human erythrocytes at 37 degrees C. Binding was assessed by comparing the chemical shifts (delta) of 2,3-diphosphoglycerate and of ATP observed in intact cells with the delta values of these organic phosphates determined in model solutions closely simulating intracellular conditions, in which percent binding was directly evaluated by membrane ultrafiltration. The results showed that the percent of bound 2,3-diphosphoglycerate in intact cells varied with pH, the state of oxygenation, and 2,3-diphosphoglycerate concentration. The values ranged from 33% in cells incubated with glucose in air at an intracellular pH of 7.2 to 100% in cells incubated with inosine in N2 at a pH of 6.75. At the same 2,3-diphosphoglycerate concentration, a greater percentage of the compound appeared to be bound in erythrocytes than in the closely simulated model system. ATP was not significantly bound to hemoglobin under any condition examined, but appeared to be strongly complexed to Mg2+ inside the erythrocyte. The binding percentages for both 2,3-diphosphoglycerate and ATP in intact cells estimated by 31P NMR spectroscopy were lower than those calculated by others from individual association constants determined for the binding of different ligands to hemoglobin.


Assuntos
Trifosfato de Adenosina/sangue , Ácidos Difosfoglicéricos/sangue , Eritrócitos/metabolismo , Hemoglobinas/metabolismo , Adulto , Humanos , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Masculino , Oxiemoglobinas/metabolismo , Ligação Proteica
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