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1.
J Appl Microbiol ; 126(6): 1910-1922, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30925006

RESUMO

AIMS: The aim was to determine the survival and persistence of Escherichia coli in soil amended with compost from different manure sources. METHOD AND RESULTS: Complex interactions of abiotic and biotic factors on E. coli survival were characterized in field experiment plots receiving randomly assigned compost treatments: dairy windrow, dairy vermicompost, poultry windrow or no compost. Biomass, activity and function of indigenous microbial communities in the composts and soils were measured concurrently to determine whether mechanisms of compost were driven by biotic or abiotic properties. E. coli persisted in compost containing poultry amendments but not in composts containing dairy or no amendments. Poultry compost contained more NH4 -N and a distinct microbial community compared to dairy and no compost treatments. A laboratory experiment performed on compost extracts suggested that E. coli survived better in extracts devoid of indigenous microbes as long as bioavailable nutrients were plentiful. CONCLUSIONS: Dairy-based composts are less likely to support E. coli survival than poultry-based composts. SIGNIFICANCE AND IMPACT OF THE STUDY: Results aid in risk assessment of the use of different types of manure-based compost and soil amendments in fruit and vegetable production by elucidating the roles of nutrient and microbial community composition on survival of E. coli in amended field soils.


Assuntos
Compostagem/métodos , Enterobacteriaceae/fisiologia , Esterco/microbiologia , Microbiologia do Solo , Spinacia oleracea/crescimento & desenvolvimento , Animais , Bovinos , Enterobacteriaceae/crescimento & desenvolvimento , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Viabilidade Microbiana , Nutrientes/química , Aves Domésticas , Solo/química
2.
Mucosal Immunol ; 7(2): 239-48, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23778354

RESUMO

Immunity to Nippostrongylus brasiliensis reinfection requires pulmonary CD4⁺ T-cell responses. We examined whether secondary lymphoid recruited or pre-existing lung CD4⁺ T-cell populations coordinated this immunity. To do this, we blocked T-cell egress from lymph nodes using Fingolimod (FTY720). This impaired host ability to resolve a primary infection but did not change effectiveness of recall immunity. Associated with this effective recall immunity was the expansion and T helper type 2 polarization of a pre-existing pulmonary CD4⁺ T-cell population. LTßR-Ig (lymphotoxin beta-receptor fusion protein)-mediated disruption of stromal cell organization of immune cells did not disrupt this recall immunity, suggesting that protection was mediated by a pulmonary interstitial residing CD4⁺ T-cell population. Adoptive transfer of N. brasiliensis-experienced pulmonary CD4⁺ T cells from FTY720-treated wild-type or T-cell interleukin (IL)-4Rα-deficient mice demonstrated protection to be IL-4Rα dependent. These results show that pre-existing CD4⁺ T cells can drive effective recall immunity to N. brasiliensis infection independently of T-cell recruitment from secondary lymphoid organs.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Memória Imunológica , Subunidade alfa de Receptor de Interleucina-4/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/metabolismo , Animais , Linfócitos T CD4-Positivos/metabolismo , Movimento Celular/genética , Movimento Celular/imunologia , Modelos Animais de Doenças , Expressão Gênica , Subunidade alfa de Receptor de Interleucina-4/genética , Pulmão/parasitologia , Linfonodos/imunologia , Linfonodos/metabolismo , Camundongos , Camundongos Knockout , Infecções por Strongylida/genética , Infecções por Strongylida/parasitologia
3.
Mucosal Immunol ; 4(1): 83-92, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20737001

RESUMO

Nippostrongylus brasiliensis infections generate pulmonary pathologies that can be associated with strong T(H)2 polarization of the host's immune response. We present data demonstrating N. brasiliensis-driven airway mucus production to be dependent on smooth muscle cell interleukin 4 receptor-α (IL-4Rα) responsiveness. At days 7 and 10 post infection (PI), significant airway mucus production was found in IL-4Rα(-/lox) control mice, whereas global knockout (IL-4Rα(-/-)) and smooth muscle-specific IL-4Rα-deficient mice (SM-MHC(Cre) IL-4Rα(-/lox)) showed reduced airway mucus responses. Furthermore, interleukin (IL)-13 and IL-5 cytokine production in SM-MHC(Cre) IL-4Rα(-/lox) mice was impaired along with a transient reduction in T-cell numbers in the lung. In vitro treatment of smooth muscle cells with secreted N. brasiliensis excretory-secretory antigen (NES) induced IL-6 production. Decreased protein kinase C (PKC)-dependent smooth muscle cell proliferation associated with cell cycle arrest was found in cells stimulated with NES. Together, these data demonstrate that both IL-4Rα and NES-driven responses by smooth muscle cells make important contributions in initiating T(H)2 responses against N. brasiliensis infections.


Assuntos
Subunidade alfa de Receptor de Interleucina-4/imunologia , Pneumopatias Parasitárias/imunologia , Miócitos de Músculo Liso/imunologia , Miócitos de Músculo Liso/metabolismo , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Ciclo Celular/genética , Citometria de Fluxo , Interleucina-13/biossíntese , Interleucina-13/imunologia , Subunidade alfa de Receptor de Interleucina-4/genética , Subunidade alfa de Receptor de Interleucina-4/metabolismo , Interleucina-5/biossíntese , Interleucina-5/imunologia , Interleucina-6/biossíntese , Interleucina-6/imunologia , Pneumopatias Parasitárias/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Muco/metabolismo , Nippostrongylus/patogenicidade , Proteína Quinase C/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Infecções por Strongylida/patologia
4.
J Affect Disord ; 112(1-3): 36-49, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18835043

RESUMO

OBJECTIVES: To evaluate the efficacy and safety of aripiprazole as acute and maintenance of effect monotherapy for acute bipolar mania. METHODS: Patients with acute bipolar I mania (DSM-IV-TR: YMRS > or =20), manic or mixed (with or without psychotic features) were randomized to double-blind aripiprazole (15-30 mg/day; n=155), placebo (n=165) or lithium (900-1500 mg/day; n=160) (1:1:1) for 3 weeks. Aripiprazole- and lithium-treated patients remained on blinded treatment for 9 additional weeks. The primary outcome was the mean change from baseline in YMRS Total score (LOCF) to Week 3. Secondary outcomes included the mean change from baseline in YMRS Total score (LOCF) at all other timepoints up to Week 12. RESULTS: Aripiprazole demonstrated significantly greater improvement than placebo in mean YMRS Total score from baseline to Day 2 (-4.3 vs.-2.8; p=0.003), and up to Week 3 (-12.6 vs. -9.0; p<0.001). Significant improvement in YMRS Total score was also seen with lithium versus placebo at Week 3 (-12.0 vs. -9.0; p=0.005). Improvements in YMRS Total score were maintained to Week 12 for aripiprazole (-14.5) and lithium (-12.7). Response rates at Week 3 were significantly higher with aripiprazole (46.8%) and lithium (45.8%) than placebo (34.4%; both p<0.05, LOCF); increasing to Week 12 with aripiprazole (56.5%) and lithium (49.0%). Most common adverse events with aripiprazole were headache, nausea, akathisia, sedation, and constipation; with lithium were nausea, headache, constipation, and tremor. CONCLUSIONS: Aripiprazole provided statistically significant improvement of acute mania within 2 days, continuing over 3 weeks and sustained over 12 weeks. The magnitude of improvement to Week 12 was similar with aripiprazole and lithium.


Assuntos
Antipsicóticos/uso terapêutico , Transtorno Bipolar/tratamento farmacológico , Piperazinas/uso terapêutico , Quinolonas/uso terapêutico , Doença Aguda , Adolescente , Adulto , Idoso , Antipsicóticos/efeitos adversos , Aripiprazol , Transtorno Bipolar/diagnóstico , Transtorno Bipolar/psicologia , Manual Diagnóstico e Estatístico de Transtornos Mentais , Método Duplo-Cego , Feminino , Seguimentos , Cefaleia/induzido quimicamente , Humanos , Compostos de Lítio/efeitos adversos , Compostos de Lítio/uso terapêutico , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Piperazinas/efeitos adversos , Placebos , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Quinolonas/efeitos adversos , Índice de Gravidade de Doença , Resultado do Tratamento , Aumento de Peso
5.
Aliment Pharmacol Ther ; 25(12): 1423-7, 2007 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-17539981

RESUMO

BACKGROUND: Helicobacter pylori infection is a major cause of peptic ulcer disease, but the prevalence of this infection has been decreasing steadily. Additionally, eradication of H. pylori decreases ulcer recurrence and prevents ulcer complications such as bleeding. AIM: To examine whether the decreased prevalence of H. pylori and increased use of eradication regimens have affected the prevalence of peptic ulcer disease-related hospitalizations. METHODS: We chose to study a period between 1996 and 2005. The number of gastric and duodenal ulcers as primary or secondary hospital discharge diagnoses per year for the 10-year span was collected from five large US hospitals. Collected data were analysed using Spearman correlation. RESULTS: No statistically significant trend was observed in the number of gastric or duodenal ulcers listed as primary or secondary discharge diagnoses at any of the five healthcare centres. CONCLUSIONS: Despite a decreasing prevalence of H. pylori and the increasing use of successful H. pylori eradication regimens, the prevalence of peptic ulcer disease and its complications has not changed. In the US other aetiologies, including non-steroidal anti-inflammatory drugs, may be playing a larger role than once thought.


Assuntos
Infecções por Helicobacter/prevenção & controle , Helicobacter pylori , Hospitalização/estatística & dados numéricos , Úlcera Péptica/microbiologia , Feminino , Infecções por Helicobacter/epidemiologia , Humanos , Masculino , Úlcera Péptica/epidemiologia , Prevalência , Estados Unidos/epidemiologia
6.
Psychoneuroendocrinology ; 28 Suppl 1: 69-82, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12504073

RESUMO

Human sexual function is complex and affected in many different ways by schizophrenia and the antipsychotic drugs used in its treatment. The evaluation of the effects of antipsychotics on sexual function in patients with schizophrenia is also complex because the deleterious effects of conventional antipsychotics are superimposed on the effects of the disease itself. Although not extensively researched, sexual dysfunction seems to be frequent in patients with schizophrenia, especially in men. Sexual dysfunction appears, in significant part, to be a direct consequence of dopamine antagonism, combined with indirect effects due to increased serum prolactin concentration. Atypical antipsychotics have a number of potential advantages over standard agents with regard to their impact on sexual function. Clinical reports indicate that atypical antipsychotics are associated with a lower incidence of sexual adverse events than conventional antipsychotics and that there may also be important differences between them in this regard. For example, dose-related increases in prolactin concentrations occur with risperidone whereas olanzapine is associated with mild and transient increases in long-term treatment. Treatment with clozapine does not result in prolactin elevation and, like olanzapine, only transient increases occur with ziprasidone therapy, but the risk of agranulocytosis with clozapine restricts its use. Quetiapine has no more effect on serum prolactin than placebo across its full dose range. Together with its low frequency of reproductive or hormonal side effects and a low incidence of extrapyramidal symptoms, the tolerability profile of quetiapine may be particularly beneficial for many patients. Sexual dysfunction can be an important source of distress to patients and adversely affects compliance, and is one of the factors that must be taken into account when selecting treatment.


Assuntos
Antipsicóticos/efeitos adversos , Disfunções Sexuais Fisiológicas/induzido quimicamente , Antipsicóticos/uso terapêutico , Feminino , Humanos , Masculino , Esquizofrenia/complicações , Esquizofrenia/tratamento farmacológico
7.
Lang Speech ; 44(Pt 2): 171-95, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11575903

RESUMO

Four experiments examined Dutch listeners' use of suprasegmental information in spoken-word recognition. Isolated syllables excised from minimal stress pairs such as VOORnaam/voorNAAM could be reliably assigned to their source words. In lexical decision, no priming was observed from one member of minimal stress pairs to the other, suggesting that the pairs' segmental ambiguity was removed by suprasegmental information. Words embedded in nonsense strings were harder to detect if the nonsense string itself formed the beginning of a competing word, but a suprasegmental mismatch to the competing word significantly reduced this inhibition. The same nonsense strings facilitated recognition of the longer words of which they constituted the beginning, but again the facilitation was significantly reduced by suprasegmental mismatch. Together these results indicate that Dutch listeners effectively exploit suprasegmental cues in recognizing spoken words. Nonetheless, suprasegmental mismatch appears to be somewhat less effective in constraining activation than segmental mismatch.


Assuntos
Fonética , Percepção da Fala , Adulto , Humanos , Países Baixos , Psicolinguística , Tempo de Reação
8.
Eur J Immunol ; 31(7): 2087-93, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11449362

RESUMO

A critical role for complement in the regulation of self tolerance has been proposed to explain the strong association between complement deficiency and autoimmunity. To elucidate the role of the classical pathway of complement in the maintenance of B cell tolerance, C1q-deficient (C1qa-/-) mice were bred with anti-hen egg lysozyme (HEL) immunoglobulin (Ig(HEL)) and soluble HEL (sHEL) transgenic mice. B cell tolerance was intact in C1qa-/- mice. In vivo, double-transgenic (Ig(HEL)/sHEL) C1qa-/- and wild-type control mice down-regulated surface immunoglobulin expression on splenocytes and equivalent numbers of HEL-binding B cells accumulated in the periphery. Maturation of B cells, evidenced by CD21 expression, was retarded to the same extent and at a similar time point. The frequency of anti-HEL-producing plasma cells and serum levels of anti-HEL immunoglobulin were comparably reduced in control and C1qa-/- double-transgenic mice compared to control Ig(HEL) and C1qa-/- Ig(HEL) mice. Furthermore, splenocytes from double-transgenic C1qa-/- or wild-type mice did not modulate intracellular calcium levels after stimulation with HEL in vitro. These data demonstrate that a stable form of B cell anergy persists in the periphery of C1qa-/- mice, suggesting that activation of the classical pathway by C1q is not essential for the maintenance of B cell tolerance in this transgenic model.


Assuntos
Linfócitos B/imunologia , Complemento C1q/genética , Via Clássica do Complemento , Tolerância a Antígenos Próprios , Animais , Autoantígenos/imunologia , Medula Óssea/imunologia , Cálcio/metabolismo , Anergia Clonal , Complemento C4b/imunologia , Imunoglobulinas/imunologia , Fígado/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Muramidase/imunologia , Plasmócitos/imunologia , Baço/imunologia
9.
J Immunol ; 167(3): 1740-7, 2001 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11466399

RESUMO

Autoimmunity results from a failure in central and/or peripheral tolerance; however, the events that initiate and maintain this dysfunction remain unclear. To better understand the mediators involved in autoimmunity, we investigated the cellular mechanisms maintaining disease in the (SWR x NZB)F(1) (SNF(1)) mouse model of systemic lupus erythematosus. Previously, we have shown that autoimmunity in this model is dependent on CD40-CD154 interactions. Herein, our studies reveal that the severity of disease in SNF(1) mice correlates with a marked increase in the frequency of apoptotic splenocytes, including a higher proportion of apoptotic dendritic cells (DC) in vivo. In addition, we demonstrate a significant disease-related increase in the absolute number of splenic CD11c(high) DC. The increased DC number appears to be attributable to DC proliferation and enhanced migration to the spleen, most likely induced by elevated splenic expression of secondary lymphoid chemokine. Importantly, these imbalances in apoptosis, secondary lymphoid chemokine expression, and DC homeostasis were reduced or normalized by anti-CD154 treatment. Thus, our data demonstrate CD154-dependent regulation of apoptosis and DC homeostasis in mice with lupus-like autoimmune disease. We suggest that these mechanisms comprise an autostimulatory loop, maintaining the cascade of autoimmunity by DC presentation of self-Ags derived from apoptotic cells and CD154-mediated costimulation.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Apoptose/imunologia , Ligante de CD40/imunologia , Células Dendríticas/imunologia , Células Dendríticas/patologia , Homeostase/imunologia , Nefrite Lúpica/imunologia , Nefrite Lúpica/patologia , Animais , Apoptose/genética , Contagem de Células , Divisão Celular/genética , Divisão Celular/imunologia , Movimento Celular/genética , Movimento Celular/imunologia , Quimiocina CCL21 , Quimiocinas CC/antagonistas & inibidores , Quimiocinas CC/biossíntese , Cruzamentos Genéticos , Regulação para Baixo/imunologia , Feminino , Homeostase/genética , Imunofenotipagem , Nefrite Lúpica/genética , Nefrite Lúpica/prevenção & controle , Ativação Linfocitária/genética , Camundongos , Camundongos Endogâmicos NZB , Índice de Gravidade de Doença , Baço/imunologia , Baço/metabolismo , Baço/patologia
10.
Lupus ; 10(1): 9-22, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11243513

RESUMO

The CD154/CD40 pathway is required for the development and progression of disease in a variety of autoimmune model systems. We have demonstrated previously that long-term anti-CD154 treatment of nephritic (SWRxNZB)F1 mice prolonged survival and preserved kidney function. Herein we ask if long-term treatment is required and further characterize the protective effect on renal pathology by examining alpha-smooth muscle actin, collagen and TGF-beta1 expression in renal tissue. The effects of anti-CD154 on brain and heart inflammation are also examined. Three dosing strategies of anti-CD154 mAb were compared in SNF1 mice that exhibited moderate or severe nephritis: (1) weekly for 6 weeks; (2) monthly; (3) weekly for 6-12 weeks followed by monthly dosing. Proteinuria, serum anti-DNA, anti-CD154 pharmacokinetics and serum soluble CD154 analyses were performed. Anti-CD154 treatment of moderate disease increased survival across all regimens, although weekly followed by monthly maintenance dosing proved most efficacious. This regime also inhibited renal alpha-smooth muscle actin and collagen deposition. Only the most aggressive anti-CD154 treatment protocol increased survival in severely nephritic mice. Long-term anti-CD154 treatment significantly inhibits key mediators of kidney fibrosis and is required to maximize survival and renal function. Potential reasons for differential therapeutic efficacy in moderately vs severely nephritic mice are discussed.


Assuntos
Ligante de CD40/imunologia , Rim/fisiopatologia , Nefrite Lúpica/imunologia , Nefrite Lúpica/fisiopatologia , Animais , Anticorpos/imunologia , Anticorpos/uso terapêutico , Fibrose/imunologia , Fibrose/prevenção & controle , Imunoterapia , Rim/imunologia , Nefrite Lúpica/tratamento farmacológico , Nefrite Lúpica/mortalidade , Nefrite Lúpica/patologia , Camundongos
11.
J Clin Microbiol ; 39(1): 212-6, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11136773

RESUMO

Helicobacter pylori infection is common in Jamaica. Describing its epidemiology in a population-based study depends largely on serology, but serologic assays have not been validated in this population. To address this issue, we examined the presence of H. pylori infection in 30 sequential adult patients with gastroduodenal symptoms by three biopsy-based methods (rapid urease test, histology, and culture) as well as by one research and two commercial enzyme-linked immunosorbent assays (ELISAs). A patient was considered H. pylori positive if the organism was detected by at least one biopsy-based method. Eighteen (60%) of the 30 patients were H. pylori positive by these criteria, whereas 21 (70%) were seropositive for H. pylori immunoglobulin G by our research ELISA. The presence of H. pylori infection in patients with gastric cancer and those with chronic gastritis was missed by biopsy-based methods but was detected by serologic assays. This observation indicates that serologic assays may be better suited for the detection of this infection in a population in which H. pylori-associated pathology is prevalent. The performance of our research ELISA in detecting biopsy-based H. pylori-positive cases was excellent, with a sensitivity and specificity of 100% and 75%, respectively. Molecular genotyping of the isolates revealed that the predominant H. pylori genotypes in this cohort of Jamaicans were cagA(+) vacA slb-m1, and iceA2. The validated serologic assay enables us to interpret epidemiologic data from population-based studies in Jamaica by comparison to those from other populations.


Assuntos
Anticorpos Antibacterianos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/imunologia , Gastropatias/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Meios de Cultura , Feminino , Gastrite/microbiologia , Gastrite/patologia , Infecções por Helicobacter/epidemiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/classificação , Helicobacter pylori/genética , Helicobacter pylori/isolamento & purificação , Humanos , Imunoglobulina G/sangue , Jamaica/epidemiologia , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Gastropatias/epidemiologia , Gastropatias/patologia , Neoplasias Gástricas/microbiologia , Neoplasias Gástricas/patologia , Urease/metabolismo
12.
Biochemistry ; 39(44): 13614-24, 2000 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-11063599

RESUMO

Structural analogues of the phytohormone (+)-abscisic acid (ABA) have been synthesized and tested as inhibitors of the catabolic enzyme (+)-ABA 8'-hydroxylase. Assays employed microsomes from suspension-cultured corn cells. Four of the analogues [(+)-8'-acetylene-ABA, (+)-9'-propargyl-ABA, (-)-9'-propargyl-ABA, and (+)-9'-allyl-ABA] proved to be suicide substrates of ABA 8'-hydroxylase. For each suicide substrate, inactivation required NADPH, increased with time, and was blocked by addition of the natural substrate, (+)-ABA. The most effective suicide substrate was (+)-9'-propargyl-ABA (K(I) = 0.27 microM). Several analogues were competitive inhibitors of ABA 8'-hydroxylase, of which the most effective was (+)-8'-propargyl-ABA (K(i) = 1.1 microM). Enzymes in the microsomal extracts also hydroxylated (-)-ABA at the 7'-position at a low rate. This activity was not inhibited by the suicide substrates, showing that the 7'-hydroxylation of (-)-ABA was catalyzed by a different enzyme from that which catalyzed 8'-hydroxylation of (+)-ABA. Based on the results described, a simple model for the positioning of substrates in the active site of ABA 8'-hydroxylase is proposed. In a representative physiological assay, inhibition of Arabidopsis thaliana seed germination, (+)-9'-propargyl-ABA and (+)-8'-acetylene-ABA exhibited substantially stronger hormonal activity than (+)-ABA itself.


Assuntos
Inibidores das Enzimas do Citocromo P-450 , Inibidores Enzimáticos/química , Oxigenases de Função Mista/antagonistas & inibidores , Ácido Abscísico/agonistas , Ácido Abscísico/análogos & derivados , Ácido Abscísico/química , Ácido Abscísico/metabolismo , Ligação Competitiva , Sistema Enzimático do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/metabolismo , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Germinação , Hidroxilação , Cinética , Oxigenases de Função Mista/química , Oxigenases de Função Mista/metabolismo , Reguladores de Crescimento de Plantas/síntese química , Reguladores de Crescimento de Plantas/química , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas , Sementes/enzimologia , Sementes/fisiologia , Especificidade por Substrato
13.
Psychon Bull Rev ; 7(3): 504-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11082857

RESUMO

Dutch-learning and English-learning 9-month-olds were tested, using the Headturn Preference Procedure, for their ability to segment Dutch words with strong/weak stress patterns from fluent Dutch speech. This prosodic pattern is highly typical for words of both languages. The infants were familiarized with pairs of words and then tested on four passages, two that included the familiarized words and two that did not. Both the Dutch- and the English-learning infants gave evidence of segmenting the targets from the passages, to an equivalent degree. Thus, English-learning infants are able to extract words from fluent speech in a language that is phonetically different from English. We discuss the possibility that this cross-language segmentation ability is aided by the similarity of the typical rhythmic structure of Dutch and English words.


Assuntos
Aprendizagem por Discriminação , Desenvolvimento da Linguagem , Linguística , Psicologia da Criança , Reconhecimento Psicológico , Feminino , Humanos , Lactente , Masculino , Multilinguismo , Países Baixos , Estados Unidos
14.
Mem Cognit ; 28(5): 746-55, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10983448

RESUMO

Languages differ in the constitution of their phonemic repertoire and in the relative distinctiveness of phonemes within the repertoire. In the present study, we asked whether such differences constrain spoken-word recognition, via two word reconstruction experiments, in which listeners turned non-words into real words by changing single sounds. The experiments were carried out in Dutch (which has a relatively balanced vowel-consonant ratio and many similar vowels) and in Spanish (which has many more consonants than vowels and high distinctiveness among the vowels). Both Dutch and Spanish listeners responded significantly faster and more accurately when required to change vowels as opposed to consonants; when allowed to change any phoneme, they more often altered vowels than consonants. Vowel information thus appears to constrain lexical selection less tightly (allow more potential candidates) than does consonant information, independent of language-specific phoneme repertoire and of relative distinctiveness of vowels.


Assuntos
Comportamento de Escolha , Linguística , Comparação Transcultural , Humanos , Fonética , Distribuição Aleatória , Tempo de Reação , Vocabulário
15.
J Pediatr Gastroenterol Nutr ; 30(4): 426-31, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10776956

RESUMO

BACKGROUND: The prevalence of Helicobacter pylori infection and its role in gastroduodenal disease in cystic fibrosis (CF) are controversial. Additionally, serologic determination of infection in this population may be inaccurate because of cross-reactivity with other bacterial species. The seroprevalence of H. pylori in a cohort of patients with CF and its cross-reactivity with Pseudomonas antibodies were investigated. METHODS: A research enzyme-linked immunosorbent assay (ELISA), and three commercial serologic assays (PyloriStat; BioWhittaker, Walkersville, MD, U.S.A.; Flexsure; SmithKline Diagnostics, Inc., San Jose, CA, U.S.A.; and HM-CAP; EPI, Stony Brook, NY, U.S.A.) at three independent laboratories determined the seroprevalence of anti-H. pylori IgG antibodies in 70 patients with CF. Cross-reactivity between solid-phase H. pylori antigens and Pseudomonas antibodies was ascertained by a competitive inhibition assay, preadsorbing sera of patients with CF with whole cell proteins from different Pseudomonas species, and serum reanalysis by each assay. Western blot analysis before and after adsorption was performed to identify potential cross-reactive antigens. RESULTS: The research ELISA, Flexsure, Pyloristat, and HM-CAP initially showed H. pylori seropositivity of 47%, 28%, 24%, and 37%, respectively. Postadsorption seropositivity declined to 8%, 0%, 0%, and 15%, respectively. All patients with research ELISA true-positive results were confirmed endoscopically to have H. pylori infection. Western blot analysis showed a 31-kDa H. pylori protein with antigenic epitopes common to both bacterial species. CONCLUSIONS: Cross-reactivity between solid-phase H. pylori antigens and anti-Pseudomonas antibodies occurs in patients with CF. A high index of suspicion should be assumed in evaluating results of serologic H. pylori tests in this population. Preadsorption of CF sera with Pseudomonas proteins should be used in serologic testing.


Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Fibrose Cística/complicações , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/imunologia , Pseudomonas/imunologia , Adolescente , Anticorpos Antibacterianos/imunologia , Western Blotting , Estudos de Coortes , Reações Cruzadas , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Feminino , Georgia/epidemiologia , Infecções por Helicobacter/sangue , Infecções por Helicobacter/complicações , Humanos , Masculino , Estudos Soroepidemiológicos
17.
Phytochemistry ; 53(3): 349-55, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10703056

RESUMO

An anthracenone analogue of abscisic acid (ABA) was synthesized as a potential photoaffinity reagent and tested for biological activity. Reaction between 10,10'-dimethoxy-9-anthrone with two equivalents of the lithiated dianion of cis-3-methylpent-2-en-4-yn-1-ol afforded an acetylenic alcohol key intermediate. Subsequent reduction of the triple bond, functional group manipulation of the side chain alcohol and deprotection of the dimethoxy protected anthrone provided anthracenone ABA analogue 7 as a potential photoaffinity reagent for ABA-binding proteins. The effect of natural ABA and the potential photoaffinity anthracenone ABA 7 on corn cell growth was determined at various concentrations. The results show that anthracenone ABA 7 is perceived as ABA-like, although producing less inhibition than ABA itself. For example, 7 at 33 microM produces approximately the same inhibition as ABA at 10 microM.


Assuntos
Ácido Abscísico/análogos & derivados , Antracenos/química , Marcadores de Fotoafinidade , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismo , Células Cultivadas , Ligação Proteica , Análise Espectral , Zea mays/citologia , Zea mays/metabolismo
18.
Curr Biol ; 10(4): 227-30, 2000 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-10704418

RESUMO

Human autoimmune diseases thought to arise from the combined effects of multiple susceptibility genes include systemic lupus erythematosus (SLE) and autoimmune diabetes. Well-characterised polygenic mouse models closely resembling each of these diseases exist, and genetic evidence links receptors for the Fc portion of immunoglobulin G (FcR) with their pathogenesis in mice and humans [1] [2] [3]. FcRs may be activatory or inhibitory and regulate a variety of immune and inflammatory processes [4] [5]. FcgammaRII (CD32) negatively regulates activation of cells including B cells and macrophages [6]. FcgammaRII-deficient mice are prone to immune-mediated disease [7] [8] [9]. The gene encoding FcgammaRII, Fcgr2, is contained in genetic susceptibility intervals in mouse models of SLE such as the New Zealand Black (NZB) contribution to the (NZB x New Zealand White (NZW)) F1 strain [1] [10] [11] and the BXSB strain [12], and in human SLE [1] [2] [3]. We therefore sequenced Fcgr2 and identified a haplotype defined by deletions in the Fcgr2 promoter region that is present in major SLE-prone mouse strains (NZB, BXSB, SB/Le, MRL, 129 [13]) and non-obese diabetic (NOD) mice but absent in control strains (BALB/c, C57BL/6, DBA/2, C57BL/10) and NZW mice. The autoimmune haplotype was associated with reduced cell-surface expression of FcgammaRII on macrophages and activated B cells and with hyperactive macrophages resembling those of FcgammaRII-deficient mice, and is therefore likely to play an important role in the pathogenesis of SLE and possibly diabetes.


Assuntos
Autoimunidade/genética , Lúpus Eritematoso Sistêmico/genética , Regiões Promotoras Genéticas , Receptores de IgG/genética , Animais , Linfócitos B/metabolismo , Sequência de Bases , Expressão Gênica , Haplótipos , Ativação Linfocitária , Macrófagos/metabolismo , Camundongos , Dados de Sequência Molecular , Deleção de Sequência
19.
J Clin Gastroenterol ; 30(1): 64-5, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10636213

RESUMO

Rapid urease test sensitivity for Helicobacter pylori is reduced in the presence of active upper gastrointestinal bleeding. The aim of this study was to evaluate the in vitro effect of whole blood on rapid urease testing. Urease solution was added to normal saline, and heparinized whole blood both positive and negative for H. pylori antibody. The mixtures were then serially diluted in saline, and/or whole blood and added to three different rapid urease kits. The admixture of urease in H. pylori-seropositive whole blood diluted in either saline or whole blood enhanced performance in both kits fourfold compared with saline alone. No false-negative results were observed in either kit. Seronegative whole blood produced similar results. Undiluted saline or whole blood produced no positive rapid urease tests. Whole blood accelerates the urease reaction in vitro. Neither H. pylori antibody-positive nor -negative whole blood adversely impacted the rapid urease test. False-negative rapid urease test results in upper gastrointestinal bleeding cannot be explained by admixture with whole blood.


Assuntos
Ensaios Enzimáticos Clínicos , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/isolamento & purificação , Urease/análise , Reações Falso-Negativas , Infecções por Helicobacter/enzimologia , Humanos
20.
Behav Brain Sci ; 23(3): 299-325; discussion 325-70, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11301575

RESUMO

Top-down feedback does not benefit speech recognition; on the contrary, it can hinder it. No experimental data imply that feedback loops are required for speech recognition. Feedback is accordingly unnecessary and spoken word recognition is modular. To defend this thesis, we analyse lexical involvement in phonemic decision making. TRACE (McClelland & Elman 1986), a model with feedback from the lexicon to prelexical processes, is unable to account for all the available data on phonemic decision making. The modular Race model (Cutler & Norris 1979) is likewise challenged by some recent results, however. We therefore present a new modular model of phonemic decision making, the Merge model. In Merge, information flows from prelexical processes to the lexicon without feedback. Because phonemic decisions are based on the merging of prelexical and lexical information, Merge correctly predicts lexical involvement in phonemic decisions in both words and nonwords. Computer simulations show how Merge is able to account for the data through a process of competition between lexical hypotheses. We discuss the issue of feedback in other areas of language processing and conclude that modular models are particularly well suited to the problems and constraints of speech recognition.


Assuntos
Cognição , Retroalimentação , Percepção da Fala , Humanos , Fonética , Semântica , Vocabulário
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