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1.
Encephale ; 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36528392

RESUMO

OBJECTIVES: Muscle dysmorphia (MD) is a disorder affecting mainly men and is characterized by significant dissatisfaction with muscles. The idea that MD could represent an addiction has been theoretically discussed, but no empirical data are available. Based on Foster et al. (2015) framework, the Addiction to Body Image Inventory (ABII) was developed. This study aims to validate the ABII and to evaluate its capacity to capture MD severity. METHODS: A first community sample of 466 participants was recruited and completed the ABII and questionnaires on MD and body esteem. A second sample of 47 men at risk of MD was recruited mostly in gyms and completed the ABII and questionnaires on MD, eating and psychological symptoms. RESULTS: With the community sample, the results showed that the ABII had a valid factorial structure, good internal consistency, and good convergent validity. With the sample of men at risk of MD, the results showed that the ABII had good convergent validity with MD and eating symptoms but not with psychological symptoms. The results of a regression model showed that the ABII explained 12% of the MD variance. CONCLUSIONS: This study brings the first measure of addiction to body image and suggests that MD must be understood as a complex phenomenon including eating symptoms and addictive tendencies.

2.
Body Image ; 34: 277-281, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32738791

RESUMO

Negative weight bias emerges at an early age. Parents play an important role in the development of their children's attitudes. In particular, mothers who place great importance on physical appearance have young daughters who exhibit more weight bias. The extent to which mothers have internalized the importance of being thin influences their own level of weight bias. Because most studies have been conducted among mothers of young children, the presence of these associations within adult dyads is unclear. The present study explored the link between mothers' weight bias and their adult daughters' weight bias, taking into account their respective level of thin-ideal internalization. Two hundred and nineteen Canadian mother-daughter adult dyads completed online questionnaires. Mothers' beliefs about people of higher weight were significantly related to their daughters' weight bias. Greater daughters' thin-ideal internalization was associated with greater weight bias across all dimensions of bias. However, fear of getting fat was the only dimension of maternal bias associated with daughters' thin-ideal internalization. In conclusion, adult daughters' weight bias was modestly linked to their mothers' negative attitudes toward individuals of higher weight.


Assuntos
Filhos Adultos/psicologia , Atitude , Julgamento , Relações Mãe-Filho/psicologia , Adulto , Idoso , Imagem Corporal/psicologia , Peso Corporal , Canadá , Feminino , Humanos , Pessoa de Meia-Idade , Modelos Psicológicos , Mães , Núcleo Familiar/psicologia , Inquéritos e Questionários , Adulto Jovem
3.
J Hum Nutr Diet ; 28(1): 37-46, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24527882

RESUMO

BACKGROUND: Differences between men and women with respect to dietary intakes and eating behaviours have been reported and could be explained by gender differences in motivational variables associated with the regulation of food intake. The main objectives of the present study were to identify gender differences in dietary intakes, eating behaviours and motivational variables and to determine how motivational variables were associated with dietary intakes and eating behaviours in men and women. METHODS: Sixty-four men and 59 premenopausal women were included in the present study and presented cardiovascular risk factors. The Regulation of Eating Behaviours scale was completed to assess motivational variables. A validated food frequency questionnaire was administered to evaluate dietary intakes and subjects completed the Three-Factor Eating questionnaire to assess eating behaviours. RESULTS: Men had higher energy intake, energy density and percentage of energy from lipids and lower percentage of energy from carbohydrates than women (P ≤ 0.04). Men also had a lower emotional susceptibility to disinhibition than women (P = 0.0001). Women reported a higher score for eating-related self-determined motivation [i.e., eating-related self-determination index (SDI)] than men (P = 0.002). The most notable gender difference in the pattern of associations was that eating-related SDI was negatively associated with energy density (r = -0.30; P = 0.02), only in women. CONCLUSIONS: Women had a better dietary profile and higher eating-related SDI than men. However, gender differences in dietary variables might be explained by a potential gender-specific pattern of association of eating-related SDI with dietary intakes and eating behaviours.


Assuntos
Ingestão de Alimentos/psicologia , Comportamento Alimentar/psicologia , Motivação , Fatores Sexuais , Adulto , Dieta/psicologia , Emoções , Ingestão de Energia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Autoimagem , Inquéritos e Questionários
4.
J Obes ; 2012: 846401, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22919471

RESUMO

The aim of this study was to determine whether women with higher depressive symptoms differed from women with lower depressive symptoms on early weight-loss, eating behaviors and psychological profiles. Among a sample of 45 overweight/obese women who had undertaken a self-initiated weight-loss attempt, two groups were formed based on scores from the Beck Depression Inventory (BDI-II), one with lower depressive symptoms (BDI-II < 10; n = 21) and one with higher depressive symptoms (BDI ≥ 10; n = 24). Even if some women in the higher depressive symptom group did not reach the clinical cut-off for depression (BDI = 14), this group tended to lose less weight in the first two months of their weight-loss attempt and to show a more disturbed eating and psychological profile compared to the group with lower depressive symptoms. In addition, among women with higher depressive symptoms, eating and psychological variables were systematically related to one another whereas these variables were not related among the other group. Results highlight the relevance of considering the presence of depressive symptoms as a marker of clinical severity among the overweight/obese population, and suggest that the BDI-II could be an interesting screening instrument to identify this particular subgroup.

5.
Rev Epidemiol Sante Publique ; 58(1): 3-11, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20097025

RESUMO

BACKGROUND: Evidence linking home hazards to falls has not been well established. The evidence-based approach to fall-risk assessment in longitudinal studies becomes difficult because of exposures that change during follow-up. We conducted a cohort study to determine the prevalence of hazards and to resolve whether they are linked to the risk of falls among 959 seniors receiving home-care services. METHODS: A home hazards assessment was completed at entry and every six months thereafter using a standardized form. The adjusted (for a number of confounding factors) relationship between home hazards and falls was estimated using a survival model taking into account updated time-varying exposures and multiple events. Falls leading to a medical consultation were examined as a secondary outcome, hypothesized as a measure of severity. FINDINGS: Home environmental hazards were found in 91% of homes, with a mean of 3.3 risks per individual. The bathroom was the most common place for hazards. The presence of hazards was significantly associated with all falls and fall-related medical consultations, and showed relatively constant effects from one fall to another. IMPLICATIONS: The current study is innovative in its approach and useful in its contribution to the understanding of the interaction between home environmental hazards and falls. Our results indicate that inattention to changes in exposure masks the statistical association between home hazards and falls. Each environmental hazard identified in the home increases the risk of falling by about 19%. These findings support the positive findings of trials that demonstrate the effectiveness of this home hazard reduction program, particularly for at-risk people.


Assuntos
Acidentes por Quedas/estatística & dados numéricos , Acidentes Domésticos/estatística & dados numéricos , Avaliação Geriátrica , Serviços de Assistência Domiciliar , Decoração de Interiores e Mobiliário/estatística & dados numéricos , Medição de Risco , Acidentes por Quedas/prevenção & controle , Acidentes Domésticos/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Lista de Checagem , Fatores de Confusão Epidemiológicos , Feminino , Pisos e Cobertura de Pisos/estatística & dados numéricos , Seguimentos , Avaliação Geriátrica/métodos , Serviços de Assistência Domiciliar/estatística & dados numéricos , Humanos , Incidência , Iluminação/estatística & dados numéricos , Modelos Lineares , Masculino , Prevalência , Modelos de Riscos Proporcionais , Quebeque/epidemiologia , Medição de Risco/organização & administração , Fatores de Risco , Gestão da Segurança/estatística & dados numéricos , Estatísticas não Paramétricas
6.
Eat Weight Disord ; 15(4): e240-6, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21406947

RESUMO

Individuals' ways of coping with psychological stress have often been associated with body weight regulation through their impact on eating behaviours. In particular, emotion-oriented and distraction-oriented coping styles have been steadily related to disordered eating. Couple dissatisfaction may be experienced as an important psychological stressor and could therefore affect eating behaviours through the use of inadequate coping strategies. The study proposes 1) to compare women reporting a low vs a high level of couple satisfaction, and 2) to test mediational models including couple satisfaction, coping styles, and eating variables. Analyses were performed among 65 overweight/obese premenopausal women who reported being weight-preoccupied. Women exhibiting couple dissatisfaction (34.8%) showed a higher level of EDE-Q restraint, more intense concerns about eating and shape, a higher level of disinhibition and susceptibility to hunger and endorsed more often a distraction-oriented coping style, independently of their body weight. Furthermore, distraction- oriented coping style seemed to be a valid mediator of the relation between couple dissatisfaction and eating behaviours. Since non-normative eating behaviours, namely disinhibition and susceptibility to hunger, have been particularly linked to a higher body weight status, it is relevant to extend the scope of interest to more distal contributing factors, such as couple dissatisfaction.


Assuntos
Adaptação Psicológica , Comportamento Alimentar/psicologia , Relações Interpessoais , Satisfação Pessoal , Estresse Psicológico/psicologia , Adulto , Imagem Corporal , Peso Corporal , Ingestão de Alimentos/psicologia , Características da Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Inquéritos e Questionários
7.
Eur J Clin Nutr ; 64(2): 194-202, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19935818

RESUMO

BACKGROUND/OBJECTIVES: To compare the effects of two dietary approaches on changes in dietary intakes and body weight: (1) an approach emphasizing nonrestrictive messages directed toward the inclusion of fruits and vegetables (HIFV) and (2) another approach using restrictive messages to limit high-fat foods (LOFAT). SUBJECTS/METHODS: A total of 68 overweight-obese postmenopausal women were randomly assigned to one of the two dietary approaches. The 6-month dietary intervention included three group sessions and ten individual sessions with a dietitian. Dietary food intake and anthropometric variables were measured at baseline, at 3 months and at 6 months. RESULTS: Energy density decreased in both groups after the intervention compared with baseline (HIFV, -0.3+/-0.2 kcal/g; LOFAT, -0.3+/-0.3 kcal/g; P<0.0001). Although body weight decreased significantly in both groups after the intervention compared with baseline (HIFV, -1.6+/-2.9 kg; LOFAT, -3.5+/-2.9 kg; P<0.0001), women in the LOFAT group lost significantly more body weight than women in the HIFV group (P=0.01). In the HIFV group, the decrease in energy density was found to be an independent predictor of body weight loss. CONCLUSIONS: The LOFAT approach induces more weight loss than does the HIFV approach in our sample of overweight-obese postmenopausal women.


Assuntos
Dieta Redutora , Ingestão de Energia , Promoção da Saúde/métodos , Obesidade/dietoterapia , Redução de Peso , Peso Corporal , Gorduras na Dieta/administração & dosagem , Feminino , Frutas , Humanos , Pessoa de Meia-Idade , Pós-Menopausa , Verduras
8.
Sci Total Environ ; 407(1): 233-41, 2008 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-18977017

RESUMO

An atmospheric dispersion model predicting ground-level concentrations from a point source of metal emissions (Murdochville smelter) was calibrated on tree rings in black spruce (Picea mariana Mill. B.S.P.) in order to reconstruct the spatial and temporal Pb-contamination pattern in the Gaspé Peninsula (Canada). Model predictions were validated with forest-floor Pb concentrations that resulted from accumulation of this element over the years and that provide a robust spatial-deposition pattern. Atmospheric emission records were also used to verify the good agreement between the smelter emissions and the temporal-information pattern present in tree rings. Tree rings that formed during the period of smelter emissions exhibited Pb concentrations that correlated with those measured in humus. Temporal variability in tree-ring concentrations was closely associated with the smelter emissions, suggesting that black spruce trees were able to record Pb pollution from a point source. However, a time gap of at least 15years must be considered between the emissions and the actual uptake and incorporation of Pb in the tree rings. A decrease in the level of contamination in the area was associated with the decrease in smelting activities, suggesting a natural resilience of the forest ecosystems to the contamination. This study highlights the strong potential for combining dendrochemical, soil, and modeling approaches in environmental research.


Assuntos
Monitoramento Ambiental/métodos , Chumbo/análise , Modelos Biológicos , Picea/crescimento & desenvolvimento , Poluentes do Solo/análise , Solo/análise , Mineração , Valor Preditivo dos Testes , Quebeque
9.
Chronic Dis Can ; 28(4): 111-20, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18625085

RESUMO

The identification of risk factors for falls in longitudinal studies becomes difficult because of exposures that change during the follow-up and also because individual subjects may experience an event more than once. These issues have been neglected and improper statistical techniques have been used. The typical approaches have been to report the proportion of fallers or the time to first fall. Both avoid the underlying assumption of independence between events and discard pertinent data. We review the existing methods and propose a Cox hazards extension. We exemplify it in the study of potential risk factors associated with all falls in 959 seniors. Finally, we compare the results of the proposed Wei, Lin, & Weissfeld (WLW) method with those of several other techniques. Stable exposure variables measured at baseline and updated time-varying exposures include socio-demographic characteristics, BMI, nutritional risk, alcohol consumption, home hazards, gait and balance, and medications. Results demonstrate that the usual methods of analyzing risk factors for falling are inappropriate, as they produce considerable biases relative to the WLW model using time-dependent covariates. Results also show that modeling for first events may be inefficient, given that the risk of occurrence varies between falls.


Assuntos
Acidentes por Quedas/estatística & dados numéricos , Serviços de Assistência Domiciliar/estatística & dados numéricos , Modelos de Riscos Proporcionais , Idoso , Consumo de Bebidas Alcoólicas/epidemiologia , Algoritmos , Benzodiazepinas/uso terapêutico , Viés , Índice de Massa Corporal , Estudos de Coortes , Feminino , Seguimentos , Marcha/fisiologia , Habitação , Humanos , Modelos Logísticos , Masculino , Destreza Motora/fisiologia , Estado Nutricional , Equilíbrio Postural/fisiologia , Medicamentos sob Prescrição , Quebeque/epidemiologia , Recidiva , Fatores de Risco , Classe Social , Fatores de Tempo , Tranquilizantes/uso terapêutico
10.
Int J Obes (Lond) ; 31(11): 1731-8, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17549091

RESUMO

OBJECTIVE: To examine associations between defined weight expectations and anthropometric profile and to identify psychological and eating behavioral factors that characterize women having more realistic weight expectations. METHODS: A nonrandom sample of 154 overweight/obese women completed the 'Goals and Relative Weight Questionnaire', which assessed four weight expectations: (1) dream weight (whatever wanted to weight); (2) happy weight (would be happy to achieve); (3) acceptable weight (could accept even if not happy with it); and (4) disappointed weight (would not view as a successful achievement). Psychological assessments evaluated dysphoria, self-esteem, satisfaction with one's body (i.e., body esteem) and weight-related quality of life. The 'Three-Factor Eating Questionnaire' assessed eating behaviors: (1) cognitive dietary restraint (control of food intake), (2) disinhibition (overconsumption of food with a loss of control), and (3) susceptibility to hunger (food intake in response to feelings and perceptions of hunger). RESULTS: Women's expectations for their dream (60.6+/-6.0 kg), happy (65.2+/-6.4 kg) and acceptable (67.9+/-6.8 kg) weights corresponded to higher percentages of weight loss (24.2+/-6.6% or 19.8+/-7.1 kg, 18.6+/-5.8% or 15.2+/-6.0 kg and 15.2+/-5.7% or 12.6+/-5.8 kg, respectively) than goals recommended for overweight individuals. Defined weight expectations were positively associated with current weight and body mass index (BMI; 0.37 < or = r < or = 0.85; P<0.0001). When women were matched one by one for their current BMI, but showing different happy BMI, women with a more realistic happy BMI were older (P=0.03) and were characterized by a greater satisfaction towards body weight (P=0.04), a higher score for flexible restraint (P=0.003) and a lower score for susceptibility to hunger (P=0.02) than women with a less realistic happy BMI. CONCLUSION: These findings suggest that having more realistic weight expectations is related to healthier psychological and eating behavioral characteristics.


Assuntos
Imagem Corporal , Peso Corporal , Comportamento Alimentar/psicologia , Sobrepeso/psicologia , Adulto , Fatores Etários , Antropometria , Índice de Massa Corporal , Dieta , Feminino , Objetivos , Humanos , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Obesidade/psicologia , Sobrepeso/fisiopatologia , Qualidade de Vida , Autoimagem , Redução de Peso
11.
Int J Obes (Lond) ; 31(2): 315-20, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16755281

RESUMO

UNLABELLED: Psychological correlates of obesity remain under controversy. As eating behaviors and dieting history have been previously related to obesity status, these dietary variables may contribute to identify overweight and obese individuals who are at higher risk of having an impaired psychological well-being. OBJECTIVE: The main purpose of this cross-sectional study was to verify the hypothesis of a relationship between weight status and psychological well-being, and to examine whether cognitive dietary restraint, disinhibition, susceptibility to hunger and dieting history could be related to psychological well-being. DESIGN AND SUBJECTS: In a sample of 101 postmenopausal women, we performed anthropometric measurements (weight, height and body mass index (BMI)), and measured psychological well-being (PER Questionnaire). The Three-Factor Eating Questionnaire (TFEQ) and a questionnaire about dieting history (dieters: had already been on a diet; non-dieters: had never been on a diet) were also administrated. RESULTS: A trend for a significant relationship was observed between BMI and psychological well-being (r=-0.17; P=0.08). Significant negative relationships were observed for disinhibition, susceptibility to hunger and all their subscales with psychological well-being (-0.28

Assuntos
Comportamento Alimentar , Inibição Psicológica , Pós-Menopausa/psicologia , Qualidade de Vida , Idoso , Antropometria , Índice de Massa Corporal , Estudos Transversais , Feminino , Indicadores Básicos de Saúde , Humanos , Fome , Pessoa de Meia-Idade , Psicometria , Autoimagem
12.
Curr Microbiol ; 35(3): 139-44, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9236294

RESUMO

The major adhesin of Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, has been previously identified as lipopolysaccharide (LPS). The purpose of the present study was to isolate and characterize A. pleuropneumoniae LPS mutants. Screening of LPS mutants was performed with colony dot and sensitivity to novobiocin. One mutant obtained by colony dot (F19) and one mutant selected for its increased sensitivity to novobiocin (33.1) did not react with a monoclonal antibody against A. pleuropneumoniae serotype 1 O-antigen compared with the parent strain. Mutants F19 and 33.1 did not express high-molecular-mass LPS bands as determined in silver-stained SDS-PAGE gels. The core-lipid A region of mutant 33.1 and of the parent strain had similar relative mobilities and reacted with serum from a pig experimentally infected with the serotype 1 reference strain of A. pleuropneumoniae, while the same region in mutant F19 showed faster migration and did not react with this serum. Use of piglet tracheal frozen sections indicated that mutant F19 was able to adhere to piglet trachea as well as the parent strain, while mutant 33.1 adhered [half as much as] the parent strain. Finally, both LPS mutants were markedly less virulent in mice than the parent strain. Taken together, our observations support the idea that LPS is an important virulence factor of A. pleuropneumoniae.


Assuntos
Actinobacillus pleuropneumoniae/patogenicidade , Lipopolissacarídeos/toxicidade , Animais , Aderência Bacteriana , Camundongos , Mutação , Suínos , Virulência
13.
Sante Ment Que ; 22(1): 43-68, 1997.
Artigo em Francês | MEDLINE | ID: mdl-9233270

RESUMO

Any therapist working with borderline patients knows that this is a crisis prone population that can be as burdening for the professional clinician as for the individual who experiences these intense relational episodes. Within this context, it is quite surprising that leaders of the behavioral approach waited until the beginning of the nineties before applying their technology to the treatment of patients diagnosed with borderline personality disorder. Linehan put numerous efforts to empirically demonstrate the efficiency of her newly developed dialectical behavior therapy, which makes it a noteworthy model. This article presents some historical and philosophical underpinnings of her approach, followed by the diagnostic criteria, the main clinical tools she advocates, the various dialectal dilemma, the treatment modes as well as an overview of the basic therapeutic strategies used in this approach.


Assuntos
Terapia Comportamental , Transtorno da Personalidade Borderline/terapia , Intervenção em Crise , Humanos
14.
Comp Immunol Microbiol Infect Dis ; 20(1): 63-74, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9023043

RESUMO

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia. The major adhesin of A. pleuropneumoniae has previously been identified as a lipopolysaccharide (LPS), and more recently, we demonstrated that high molecular mass LPS were involved in A. pleuropneumoniae adherence to porcine respiratory tract cells. We postulated that immunization with a LPS-based vaccine may confer a protective immunity. The high molecular mass O-polysaccharides obtained after acid hydrolysis and chromatographic separation were conjugated to bovine serum albumin (BSA) as a protein carrier. Groups of mice were injected twice with the following antigen preparations: whole-cell preparation, outer membrane preparation, O-polysaccharide-BSA conjugate, hydrolyzed LPS and phenol/water extracted LPS. A combination of different adjuvants was also used during these immunization procedures to induce a stronger immunological response to the polysaccharide antigen. Two weeks after the second injection, the mice were challenged intranasally with either homologous A. pleuropneumoniae serotype 1 strain or a serotype 5 strain. The highest survival rate, up to 80%, compared to the control groups (P < 0.05), was recorded when the mice were injected twice with 15 micrograms of carbohydrates of O-polysaccharide-BSA conjugate mixed with the saponin-derived adjuvant Quil A. Survival rates of between 60 and 70%, twice those observed in the control groups immunized with PBS, were recorded in mice injected with the O-polysaccharide-BSA conjugate mixed with other adjuvant preparations such as alhydrogel, peanut oil and Freund's incomplete adjuvant. However, the protection induced by the conjugate antigen preparation was serotype specific, because mice challenged with a serotype 5 strain were killed. Taken together, these results confirm the important role of A. pleuropneumoniae LPS in pathogenesis.


Assuntos
Infecções por Actinobacillus/imunologia , Infecções por Actinobacillus/prevenção & controle , Actinobacillus pleuropneumoniae/química , Actinobacillus pleuropneumoniae/imunologia , Lipopolissacarídeos/imunologia , Adjuvantes Imunológicos , Hidróxido de Alumínio/imunologia , Animais , Anticorpos Antibacterianos/análise , Membrana Celular/imunologia , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Adjuvante de Freund/imunologia , Immunoblotting , Lipopolissacarídeos/isolamento & purificação , Camundongos , Antígenos O/imunologia , Óleos de Plantas , Soroalbumina Bovina/imunologia , Vacinas/imunologia , Vacinas Conjugadas/imunologia , Vacinas Sintéticas/imunologia
15.
Can J Microbiol ; 42(8): 855-8, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8776854

RESUMO

Lipopolysaccharides (LPS) of Actinobacillus pleuropneumoniae were separated by Tricine-SDS-polyacrylamide gel electrophoresis, which has been shown to improve resolution of low-molecular-mass fast migrating bands. Strains representing the 12 serotypes of A. pleuropneumoniae can be divided in two groups according to the gel mobility of the core - lipid A region of their LPS. The first electromorphic core type (core type I), found in serotypes 1, 6, 9, and 11, had a migration slower than Salmonella typhimurium Ra LPS. The second electromorphic core type (core type II), found in the remaining serotypes (i.e., 2, 3, 4, 5, 7, 8, 10, and 12) had a migration similar to S. typhimurium Ra LPS. Furthermore, we observed that these two core types were antigenically different. Western blot analyses indicated that core - lipid A region of LPS from electromorphic core type I strains reacted when probed with serum from a pig experimentally infected with a core type I strain but not when probed with serum from a pig experimentally infected with a core type II strain. Conversely, core - lipid A region of LPS from electromorphic core type II strains reacted only when probed with serum from a pig experimentally infected with a core type II strain. Our results, based on both electrophoretic mobility and antigenicity, suggest the presence of two LPS core types in A. pleuropneumoniae.


Assuntos
Actinobacillus pleuropneumoniae/química , Actinobacillus pleuropneumoniae/classificação , Lipídeo A/química , Western Blotting , Eletroforese em Gel de Poliacrilamida , Sorotipagem , Coloração pela Prata , Especificidade da Espécie
16.
Infect Immun ; 63(2): 656-62, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7822035

RESUMO

A previous study indicated that lipopolysaccharides (LPS) extracted from Actinobacillus pleuropneumoniae bind two low-molecular-mass proteins, of approximately 10 and 11 kDa, present in porcine respiratory tract secretions (M. Bélanger, D. Dubreuil, and M. Jacques, Infect. Immun. 62:868-873, 1994). In the present study, we determined the N-terminal amino acid sequences of these two proteins, which revealed high homology with the alpha and beta chains of pig hemoglobin. Some isolates of A. pleuropneumoniae were able to use hemoglobin from various animal species as well as other heme compounds as sole sources of iron for growth, while other isolates were unable to use them. Immunoelectron microscopy showed binding of pig hemoglobin at the surface of all A. pleuropneumoniae isolates as well as labeling of outer membrane blebs. We observed, using Western blotting (immunoblotting), that the lipid A-core region of LPS of all isolates was binding pig hemoglobin. Furthermore, lipid A obtained after acid hydrolysis of LPS extracted from A. pleuropneumoniae was able to bind pig hemoglobin and this binding was completely abolished by preincubation of lipid A with polymyxin B but was not inhibited by preincubation with glucosamines. Fatty acids constituting the lipid A of A. pleuropneumoniae, namely, dodecanoic acid, tetradecanoic acid, 3-hydroxytetradecanoic acid, hexadecanoic acid, and octadecanoic acid, were also binding pig hemoglobin. Our results indicate that LPS of all A. pleuropneumoniae isolates tested bind pig hemoglobin and that lipid A is involved in this binding. Our results also indicate that some A. pleuropneumoniae isolates are, in addition, able to use hemoglobin for growth. Binding of hemoglobin to LPS might represent an important means by which A. pleuropneumoniae acquires iron in vivo from hemoglobin released from erythrocytes lysed by the action of its hemolysins.


Assuntos
Actinobacillus pleuropneumoniae/patogenicidade , Proteínas de Fase Aguda , Proteínas de Transporte , Hemoglobinas/metabolismo , Lipopolissacarídeos/metabolismo , Glicoproteínas de Membrana , Sequência de Aminoácidos , Animais , Cromatografia de Afinidade , Técnicas In Vitro , Ferro/metabolismo , Lipídeo A/metabolismo , Dados de Sequência Molecular , Polimixina B/farmacologia , Ligação Proteica , Sistema Respiratório/microbiologia , Suínos
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