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Proliferative enteropathy (PE) is characterized by diarrhea and reduced weight gains in growing pigs and intestinal hemorrhage in finishers. Vaccination, antibiotic medication, and improved hygiene can control PE, but their efficacy depends upon the epidemiology of PE. This study monitored the timing and severity of PE in 84 commercial pens across seven treatments, including disinfection, vaccination, no treatment, medication with olaquindox (50, 25 and 12.5 ppm), and combined disinfection and vaccination. Vaccination with or without lime disinfection suppressed clinical signs of PE and reduced the number of excreted L. intracellularis relative to untreated pigs housed in cleaned or cleaned and disinfected pens between 9 and 17 weeks of age. Continuous olaquindox mediation to 17 weeks of age prevented L. intracellularis infection, leaving finisher pigs naïve. These finisher pigs suffered an outbreak of hemorrhagic enteropathy with significant reductions in weight gain, feed intake, and mortalities of 4.6%. Over the 13 week grow/finish period, vaccinated pigs housed in disinfected pens showed significantly higher weight gain and feed intake relative to all other treatments, equating to a weight gain difference of between 3.6 and 3.9 kg per pig. Monitoring the immune response and fecal excretion of L. intracellularis in pens of pigs enabled effective PE control strategies to be evaluated on the farm.
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OBJECTIVE: Infants and children diagnosed with a conductive hearing loss (CHL) are often referred for otolaryngology assessment. Although this is also a regular occurrence for infants diagnosed with a CHL through Universal Newborn Hearing Screening (UNHS), less is known about these infants and their outcomes. Using a cohort of infants diagnosed with CHL through UNHS and referred to otolaryngology, this study aimed to investigate the relationship between specific demographic or clinical characteristics and 1) triage category 2) middle ear diagnosis and intervention and, 3) service-related factors at otolaryngology. METHODS: Retrospective analysis through clinical chart review was performed on all infants born between January 2014 and December 2017 who referred on UNHS, diagnosed with a CHL and referred to the Queensland Children's Hospital. Descriptive analysis and Chi squared analysis was conducted on data from 95 records. RESULTS: Analysis between all infants referred from UNHS and those who referred, diagnosed with CHL and then referred to otolaryngology suggest that bilateral referrals/medical exclusion, preterm and infants with ≥1 risk factors are more readily associated with referral to otolaryngology for CHL. Nearly all (92.86 %) infants who were referred to otolaryngology had a primary diagnosis of OM and most infants (89.66 %) received grommets as an intervention. The average age of first appointment at otolaryngology was 427 days, the average age of intervention was 579 days and the average occasions of service at otolaryngology was 6.72. CONCLUSION: This paper provides a snapshot into the journey and outcomes of infants referred from UNHS, diagnosed with CHL, and referred to otolaryngology. Further investigation in both general and UNHS populations is needed to better understand and apply these findings.
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Perda Auditiva Condutiva , Testes Auditivos , Triagem Neonatal , Humanos , Recém-Nascido , Perda Auditiva Condutiva/diagnóstico , Estudos Retrospectivos , Masculino , Feminino , Lactente , Encaminhamento e Consulta/estatística & dados numéricos , Queensland , Otolaringologia , Fatores de RiscoRESUMO
Pigs are especially vulnerable to intestinal pathogens and dysbiosis in the first two weeks after weaning. Infection with enterotoxigenic strains of Escherichia coli (ETEC) in combination with poor nutrition and hygiene can lead to diarrhea, poor growth and increased mortality. While neomycin and zinc oxide can prevent post-weaning diarrhea (PWD), their broad-spectrum activity also kills commensal microbiota and can lead to the emergence of heavy metal and antimicrobial resistance. Bromelain prevents attachment of F4 ETEC to intestinal enterocytes by cleaving the host receptor. In controlled environmental facilities, weaned pigs treated with either therapeutic levels of neomycin sulfate, zinc oxide, bromelain or non-treated were monitored for diarrhea, weight gain, feed intake, feed efficiency, excretion of F4 ETEC, changes to their intestinal microbiomes and antimicrobial resistance in E. coli. The treatment effects were evaluated at weaning, during two weeks of treatment and for three weeks after treatments ceased. Minimal clinical signs of PWD were observed, except in zinc-treated pigs post treatment. Intestinal dysbiosis was observed in response to diarrhea and in pigs treated with both neomycin and zinc. Antimicrobial resistance increased in commensal E. coli isolated from neomycin- and zinc-treated pigs. In contrast, bromelain controlled PWD and prevented intestinal dysbiosis without inducing antimicrobial resistance.
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An outbreak of food poisoning in New South Wales (NSW) Australia in 2018, caused by Salmonella enterica serovar Enteritidis phage type 12 (PT12), was traced to eggs consumed from a NSW layer flock. This was the first report of Salmonella Enteritidis infection in NSW layer flocks, despite ongoing environmental monitoring. Clinical signs and mortalities were minimal in most flocks, although seroconversion and infection were demonstrated in some flocks. An oral dose-response challenge study with Salmonella Enteritidis PT12 was undertaken in commercial point-of-lay hens. Cloacal swabs collected at 3, 7, 10, and 14 days postinoculation and caeca, liver, spleen, ovary, magnum, and isthmus tissues collected at necropsy at either 7 or 14 days were processed for Salmonella isolation (AS 5013.10-2009 from ISO6579:2002). Histopathology was performed on the above tissues, as well as lung, pancreas, kidney, heart, and additional intestinal and reproductive tract tissues. Salmonella Enteritidis was consistently detected in cloacal swabs between 7 and 14 days postchallenge. The Salmonella Enteritidis PT12 isolate successfully colonized the gastrointestinal tract, liver, and spleen of all hens orally challenged with 107, 108, and 109 Salmonella Enteritidis, and less consistently colonized their reproductive tracts. On histopathology, mild lymphoid hyperplasia in the liver and spleen, along with hepatitis, typhlitis, serositis, and salpingitis, was observed at 7 and 14 days postchallenge, with a greater proportion of affected birds in the two higher dose groups. Diarrhea and culture of Salmonella Enteritidis from heart blood were not detected in challenged layers. The NSW isolate of Salmonella Enteritidis PT12 was able to invade and colonize the birds' reproductive tracts as well as a wide range of other tissues, indicating the potential for these naive commercial hens to contaminate their eggs.
La inoculación oral de gallinas ponedoras en el pico de postura con la cepa de Salmonella Enteritidis PT12 del brote en Nueva Gales del Sur causa infección, pero una histopatología mínima. Un brote de intoxicación alimentaria en Nueva Gales del Sur (NSW), Australia en 2018, causado por Salmonella enterica serovar Enteritidis fagotipo 12, se rastreó hasta los huevos consumidos de una parvada de ponedoras de NSW. Este fue el primer informe de infección por Salmonella Enteritidis en parvadas de ponedoras de NSW, a pesar del monitoreo ambiental continuo. Los signos clínicos y la mortalidad fueron mínimos en la mayoría de las parvadas, aunque se demostró seroconversión e infección en algunas parvadas. Se llevó a cabo un estudio de desafío oral para evaluar la dosis y su respuesta para Salmonella Enteritidis PT12 en gallinas ponedoras comerciales. Los hisopos cloacales recolectados a los tres, siete, diez y 14 días posteriores a la inoculación y los tejidos de ciego, hígado, bazo, ovario, magnum e istmos recolectados en la necropsia a los siete o 14 días se procesaron para el aislamiento de Salmonella (AS 5013.10-2009 del estándar ISO6579: 2002). Se realizó histopatología en los tejidos anteriormente mencionados, así como de pulmón, páncreas, riñón, corazón y tejidos intestinales y del tracto reproductivo adicionales. Salmonella Enteritidis se detectó consistentemente en hisopos cloacales entre los siete y 14 días después del desafío. El aislado de Salmonella Enteritidis PT12 colonizó con éxito el tracto gastrointestinal, el hígado y el bazo de todas las gallinas desafiadas por vía oral con dosis de 107, 108 y 109 de Salmonella Enteritidis, pero colonizó de manera menos consistente sus tractos reproductivos. En la histopatología, se observó hiperplasia linfoide leve en el hígado y el bazo, junto con hepatitis, tiflitis, serositis y salpingitis, a los siete y 14 días posteriores a la exposición, con una mayor proporción de aves afectadas en los dos grupos de dosis más altas. En las ponedoras desafiadas no se detectaron diarrea ni cultivo de Salmonella Enteritidis de sangre colectada del corazón. El aislamiento de Salmonella Enteritidis PT 12 de Nueva Gales del Sur pudo invadir y colonizar los tractos reproductivos de las aves, así como una amplia gama de otros tejidos, lo que indica el potencial de estas gallinas comerciales sin inmunidad para contaminar sus huevos.
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Bacteriófagos , Doenças das Aves Domésticas , Salmonelose Animal , Animais , Feminino , Salmonella enteritidis/fisiologia , Galinhas , New South Wales/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Óvulo , Surtos de Doenças/veterinária , Salmonelose Animal/epidemiologia , OvosRESUMO
OBJECTIVE: Infants diagnosed with a conductive hearing loss (CHL) are at increased risk of developmental delays. Using a sample of infants diagnosed with CHL through UNHS, this study aimed to investigate the relationship between specific demographic or clinical characteristics and 1) occasions of service to reach a hearing diagnosis and 2) the profile of CHL. METHODS: Retrospective analysis was conducted for all infants with CHL born between 01/01/2007 and 31/12/2018 who had received UNHS. Chi squared analysis was conducted on data from 1208 records. RESULTS: Infants with ≥1 risk factor for hearing loss were more likely to attend more than three occasions of service. Infants who were bilateral refer/medical exclusion, Torres Strait Islander, had ≥1 risk factors for hearing loss or were born pre-term had greater proportions of bilateral CHL than unilateral CHL. Mild to moderate was the most frequent degree of CHL, although a unilateral or bilateral CHL did not have an association with the severity of CHL. Compared to other risk factors, infants with a syndrome had greater proportions of bilateral than unilateral CHL. Risk factors of craniofacial abnormality, prolonged ventilation, or syndrome had greater proportions of mild to moderate CHL than moderate or greater. On average, infants were diagnosed with a CHL at 37.29 weeks of age. CONCLUSION: These findings highlight the relationship between clinical/demographic characteristics and occasions of service to diagnose CHL in children, including the CHL profile. An understanding of this relationship may help clinicians to better plan, assess and manage infants diagnosed with a CHL through UNHS.
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Surdez , Perda Auditiva , Lactente , Criança , Recém-Nascido , Humanos , Perda Auditiva Condutiva/diagnóstico , Perda Auditiva Condutiva/epidemiologia , Perda Auditiva Condutiva/etiologia , Estudos Retrospectivos , Perda Auditiva/diagnóstico , Testes Auditivos , Surdez/complicações , Fatores de Risco , Audição , Triagem NeonatalRESUMO
BACKGROUND: Universal Newborn Hearing Screening (UNHS) aims to identify infants born with a permanent hearing loss. However, many are also diagnosed with a conductive hearing loss (CHL) and are at subsequent risk for developmental delays. The aim of this study was to investigate the prevalence of CHL and determine which clinical characteristics collected at birth, predict CHL within UNHS. MATERIALS AND METHODS: Retrospective analysis was conducted on all infants born between January 01, 2007 and December 31, 2018. During this period, 731,234 infants were screened, 9802 were direct referrals, and 1208 identified with a CHL. Chi squared analysis and logistic regression was conducted to determine CHL prevalence and identify which clinical characteristics predict CHL. RESULTS: The prevalence of CHL was 12.32%. Following adjustments for collinearity, clinical characteristics that could predict CHL were: bilateral referrals/medical exclusions to screen (Odds ratio, OR 1.89; 95% CI: 1.65-2.1), ≥1 risk factor for hearing loss (OR 2.03; 95% CI: 1.76-2.34), pre-term birth (OR 1.82; 95% CI: 1.57-2.10), male (OR 1.21; 95% CI: 1.07-1.37), and Indigenous status: 'Aboriginal (not Torres Strait Islander)' (OR 1.27; 95% CI:1.03-1.57 and 'not stated' (OR 2.95; 95% CI: 2.02-4.30). CONCLUSION: CHL within UNHS was highly prevalent, with six clinical characteristics that can predict that likelihood of an infant being diagnosed with a CHL. This data could be used to create alternative care pathways for infants with CHL, enabling early and targeted assessments, thereby reducing the risk of developmental delays for these infants.
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Surdez , Perda Auditiva , Surdez/complicações , Audição , Perda Auditiva/diagnóstico , Perda Auditiva Condutiva/complicações , Perda Auditiva Condutiva/diagnóstico , Perda Auditiva Condutiva/epidemiologia , Testes Auditivos , Humanos , Lactente , Recém-Nascido , Masculino , Triagem Neonatal , Estudos RetrospectivosRESUMO
Post weaning diarrhea (PWD) caused by enterotoxigenic strains of E. coli (ETEC) remains a major problem in the industry, causing decreases in performance and survival of weaned pigs. Traditionally, antimicrobials have been used for its mitigation/control. This study tested the hypothesis that a combination of two organic acid (OA)-based commercial feed additives, Presan FX [an OA, medium-chain fatty acid (MCFA) and phenolic compound-based product] and Fysal MP (free and buffered OA based on formic acid), would reduce PWD and improve post-weaning performance in pigs challenged with an F4-ETEC. This combination was assessed against a Negative control diet without any feed additives and a diet containing amoxicillin. Combined with a reduction in temperature during the infection period, inoculation with F4-ETEC resulted in 81% of pigs developing diarrhea, but with no differences between treatments (P > 0.05). However, between days 14 to 20 of the study and due to colonization by Salmonella serovars, pigs fed the combination of Presan FX and Fysal MP showed less (P = 0.014) diarrhea commensurate with a lower (P = 0.018) proportion of Salmonella numbers relative to total bacterial numbers. This caused less (P = 0.049) therapeutic antibiotic administrations relative to the diet with amoxicillin during this time. The diversity of bacteria within amoxicillin-treated pigs was lower (P = 0.004) than the diversity in control or Presan FX + Fysal MP-treated pigs (P = 0.01). Pair-wise comparisons showed that amoxicillin-treated pigs had altered (P < 0.001) fecal microbial communities relative to both Presan FX + Fysal MP-treated pigs and control pigs. Amoxicillin-treated pigs were characterized by an increased abundance of bacterial families generally linked to inflammation and dysbiosis in the gastrointestinal tract (GIT), whereas Presan FX + Fysal MP-treated pigs had an increased abundance of bacterial families considered beneficial commensals for the GIT. Control pigs were characterized by an increased abundance of Spirochaetaceae associated with healthy piglets, as well as bacterial families associated with reduced feed intake and appetite. The combination of two OA-based feed additives did not reduce the incidence of F4 ETEC-associated diarrhea nor enhance performance. However, the combination markedly reduced diarrhea caused by Salmonella that occurred following the ETEC infection, commensurate with less therapeutic administrations relative to the diet with amoxicillin.
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PURPOSE: UK government policy emphasizes the importance of continuing to work for recovery from poor health, yet sickness presenteeism (going to work whilst ill) is commonly regarded as having negative consequences for organizations and individuals. Our study explores experiences of working after onset of rheumatoid arthritis (RA), a chronic musculoskeletal disorder characterized by high rates of work disability. MATERIALS AND METHODS: An exploratory qualitative study consisting of in-depth interviews and six-month follow-up with 11 men and women with RA employed at disease onset. RESULTS: We expand upon previous models of sickness presenteeism by distinguishing between presenteeism that occurs voluntarily (wanting to work despite illness) and involuntarily (feeling pressured to work when ill). RA onset affected participants' ability to work, yet motivation to remain working remained high. The implementation of workplace adjustments enabled participants to stay working and restore their work capacity. Conversely, managers' misinterpretation of organizational sickness absence policies could lead to involuntary presenteeism or delayed return to work, conflicting with the notion of work as an aid to recovery. CONCLUSION: Workplace adjustments can facilitate voluntary sickness presenteeism. To reduce work disability and sickness absence, organizational policies should be sufficiently flexible to accommodate the needs of workers with fluctuating conditions. Implications for rehabilitation Individuals with rheumatoid arthritis (RA) are at high risk of work disability. Individuals' motivation to remain in work following onset of RA remains high, yet sickness presenteeism (working while ill) has received largely negative attention. It is important to distinguish between voluntary and involuntary forms of sickness presenteeism. Workplace adjustments facilitate voluntary sickness presenteeism (wanting to work despite illness) and improve job retention and productivity among workers with RA. Involuntary presenteeism (feeling pressured to work while ill) may occur if organizational policies are not sufficiently flexible to accommodate the needs of workers with RA.
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Artrite Reumatoide/psicologia , Presenteísmo , Trabalho/psicologia , Adaptação Fisiológica , Adaptação Psicológica , Adulto , Acessibilidade Arquitetônica , Feminino , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Política Organizacional , Reino UnidoRESUMO
This study investigated the cause of recent outbreaks of septicaemia in neonatal pigs in Australia (Victoria and Queensland). Septicaemia in neonatal pigs is commonly caused by enterotoxigenic E. coli, extraintestinal pathogenic E. coli and beta-haemolytic streptococci. Infrequent causes of septicaemia are Actinobacillus suis and Citrobacter freundii. Therefore, it was quite unexpected when Klebsiella pneumoniae was isolated in predominant growth from multiple organs of pigs dying of septicaemia from six days of age. Two cases in Victoria were associated with multilocus sequence type 25 (ST25), whereas the cases on a single farm in Queensland were associated with two different sequence types (ST278 and ST1978). Similar outbreaks of septicaemia have also occurred in England, but all were associated with K. pneumoniae ST25. The K. pneumoniae sequence types did not cluster phylogenetically into groups of isolates from the same geographical location or into groups which caused either septicaemia or pneumonia. Antibiotic resistance also varied between isolates and showed neomycin resistance in Queensland. These results suggest that several sequence types of K. pneumoniae are involved in causing outbreaks of septicaemia in neonatal pigs, in addition to its previously recognised role in pneumonia and mastitis.
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Surtos de Doenças/veterinária , Infecções por Klebsiella/veterinária , Klebsiella pneumoniae/isolamento & purificação , Pneumonia/veterinária , Sepse/veterinária , Animais , Animais Recém-Nascidos , Técnicas de Tipagem Bacteriana/veterinária , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Tipagem de Sequências Multilocus/veterinária , Pneumonia/epidemiologia , Pneumonia/microbiologia , Sepse/epidemiologia , Sepse/microbiologia , SuínosRESUMO
RATIONALE: The association between sickness presenteeism, defined as going to work despite illness, and different health outcomes is increasingly being recognized as a significant and relevant area of research. However, the long term effects on future employee health are less well understood, and to date there has been no review of the empirical evidence. The aim of this systematic review was to present a summary of the sickness presenteeism evidence so far in relation to health and wellbeing over time. METHODS: Eight databases were searched for longitudinal studies that investigated the consequences of workplace sickness presenteeism, had a baseline and at least one follow-up point, and included at least one specific measure of sickness presenteeism. Of the 453 papers identified, 12 studies met the eligibility criteria and were included in the review. FINDINGS: We adopted a thematic approach to the analysis because of the heterogeneous nature of the sickness presenteeism research. The majority of studies found that sickness presenteeism at baseline is a risk factor for future sickness absence and decreased self-rated health. However, our findings highlight that a consensus has not yet been reached in terms of physical and mental health. This is because the longitudinal studies included in this review adopt a wide variety of approaches including the definition of sickness presenteeism, recall periods, measures used and different statistical approaches which is problematic if this research area is to advance. Future research directions are discussed.
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Comportamentos Relacionados com a Saúde , Saúde Ocupacional/normas , Presenteísmo , Local de Trabalho/psicologia , Humanos , Licença MédicaRESUMO
The effects of feeding a diet supplemented with zinc oxide (ZnO) or a blend of organic acids, cinnamaldehyde and a permeabilizing complex (OACP) on post-weaning diarrhoea (PWD) and performance in pigs infected with enterotoxigenic E. coli (ETEC) were examined. Additionally, changes in selected bacterial populations and blood measures were assessed. A total of 72 pigs weaned at 22 d of age and weighing 7.2 ± 1.02 kg (mean ± SEM) was used. Treatments were: base diet (no antimicrobial compounds); base diet + 3 g ZnO/kg; base diet + 1.5 g OACP/kg. Dietary treatments started on the day of weaning and were fed ad libitum for 3 weeks. All pigs were infected with an F4 ETEC on d 4, 5 and 6 after weaning. The incidence of PWD was lower in pigs fed ZnO ( p = 0.026). Overall, pigs fed ZnO grew faster ( p = 0.013) and ate more ( p = 0.004) than the base diet-fed pigs, with OACP-fed pigs performing the same ( p > 0.05) as both the ZnO- and base diet-fed pigs. Feed conversion ratio was similar for all diets ( p > 0.05). The percentage of E. coli with F4 fimbriae was affected a day by treatment interaction ( p = 0.037), with more E. coli with F4 fimbriae found in pigs fed ZnO on d 11 ( p = 0.011) compared to base diet-fed pigs. Only significant time effects ( p < 0.05) occurred for blood measures. Under the conditions of this study, inclusion of OACP gave statistically similar production responses to pigs fed ZnO, however pigs fed ZnO had less PWD compared to OACP- and the base diet-fed pigs.
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The primary objective of this study was to observe the effect of hypnosis on hot flashes (HF) and overall quality of life in symptomatic patients. A secondary objective was to observe the effect of hypnosis on fatigue. Ten healthy volunteers and four breast cancer patients (total 14 patients) with symptoms of HF were treated with four, 1 h/wk sessions of hypnosis. The same physician, with the help of a nurse, conducted every session. All subjects recorded frequency, duration, and severity of HF in a HF diary. The QLQ-C30 and Brief Fatigue Inventory forms were used to assess the impact on quality of life and fatigue, respectively. The statistical evaluations were performed, including analysis of variance and nonparametric procedures. The frequency (p < 0.0001), duration (p < 0.0001), and severity (p < 0.0001) of HF were significantly reduced. The overall quality of life was also improved (p = 0.05). The subjects enjoyed better sleep and had less insomnia (p = 0.012). There was a significant improvement on current fatigue level (p = 0.017), but we did not find a statistically significant reduction in the total fatigue level. We conclude that hypnosis appears to be a feasible and promising intervention for HF, with a potential to improve quality of life and insomnia. Although improvement in current level of fatigue was observed in this pilot study, total fatigue improvement did not reach statistical significance.
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Fadiga/terapia , Fogachos/terapia , Hipnose , Menopausa/fisiologia , Qualidade de Vida , Distúrbios do Início e da Manutenção do Sono/terapia , Adulto , Análise de Variância , Neoplasias da Mama/complicações , Fadiga/etiologia , Feminino , Fogachos/etiologia , Humanos , Hipnose/métodos , Menopausa/psicologia , Pessoa de Meia-Idade , Projetos Piloto , Índice de Gravidade de Doença , Distúrbios do Início e da Manutenção do Sono/etiologia , Inquéritos e Questionários , Fatores de Tempo , Resultado do Tratamento , Estados UnidosRESUMO
Serology indicates that Lawsonia intracellularis infection is widespread in many countries, with most pigs seroconverting before 22 weeks of age. However, the majority of animals appear to be sub-clinically affected, demonstrated by the low reported prevalence of diarrhoea. Production losses caused by sub-clinical proliferative enteropathy (PE) are more difficult to diagnose, indicating the need for a quantitative L. intracellularis assay that correlates well with disease severity. In previous studies, increasing numbers of L. intracellularis in pig faeces, quantified with a real time polymerase chain reaction (qPCR), showed a strong negative correlation with average daily gain (ADG). In this study, the association between faecal L. intracellularis numbers and PE severity was examined in two L. intracellularis experimental challenge trials (n1=32 and n2=95). The number of L. intracellularis shed in individual faeces was determined by qPCR on days 0, 7, 14, 17 and 21 days post challenge, and average daily gain was recorded over the same period. The severity of histopathological lesions of PE was scored at 21 days post challenge. L. intracellularis numbers correlated well with histopathology severity and faecal consistency scores (r=0.72 and 0.68, respectively), and negatively with ADG (r=-0.44). Large reductions in ADG (131 g/day) occurred when the number of L. intracellularis shed by experimentally challenged pigs increased from 10(7) to 10(8)L. intracellularis, although smaller ADG reductions were also observed (15 g/day) when the number of L. intracellularis increased from 10(6) to 10(7)L. intracellularis.
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Infecções por Desulfovibrionaceae/veterinária , Lawsonia (Bactéria)/crescimento & desenvolvimento , Doenças dos Suínos/diagnóstico , Aumento de Peso , Animais , Infecções por Desulfovibrionaceae/diagnóstico , Infecções por Desulfovibrionaceae/patologia , Diarreia/microbiologia , Diarreia/patologia , Diarreia/veterinária , Fezes/microbiologia , Feminino , Enteropatias/microbiologia , Enteropatias/patologia , Enteropatias/veterinária , Lawsonia (Bactéria)/genética , Masculino , Reação em Cadeia da Polimerase , Índice de Gravidade de Doença , Sus scrofa/crescimento & desenvolvimento , Sus scrofa/microbiologia , Suínos/crescimento & desenvolvimento , Suínos/microbiologia , Doenças dos Suínos/microbiologia , Doenças dos Suínos/patologiaRESUMO
B7-1 and B7-2 are generally thought to have comparable structures and affinities for their receptors, CD28 and CTLA-4, each of which is assumed to be bivalent. We show instead (1) that B7-2 binds the two receptors more weakly than B7-1, (2) that, relative to its CTLA-4 binding affinity, B7-2 binds CD28 2- to 3-fold more effectively than B7-1, (3) that, unlike B7-1, B7-2 does not self-associate, and (4) that, in contrast to CTLA-4 homodimers, which are bivalent, CD28 homodimers are monovalent. Our results indicate that B7-1 markedly favors CTLA-4 over CD28 engagement, whereas B7-2 exhibits much less bias. We propose that the distinct structures and binding properties of B7-1 and B7-2 account for their overlapping but distinct effects on T cell responses.