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OBJECTIVE: To explore associations between hip muscle strength and cartilage defects (presence and severity) on magnetic resonance imaging (MRI) in young adults with hip/groin pain participating in sub-elite football. DESIGN: Sub-elite football players with hip/groin pain (>6 months) completed assessments of isometric hip strength and functional task performance. Hip cartilage defects were assessed using the Scoring Hip Osteoarthritis with MRI tool. This exploratory, cross-sectional study used logistic and negative binomial models to assess the relationships between hip muscle strength or functional task performance and hip cartilage defects, controlling for body mass index, age, testing site and cam morphology, incorporating sex-specific interaction terms. RESULTS: One hundred and eighty-two (37 women) sub-elite (soccer or Australian football) players with hip/groin pain (age 26 ± 7 years) were included. Greater hip extension strength was associated with higher cartilage total score (adjusted incidence rate ratio [aIRR] 1.01, 95%CI: 1.0 to 1.02, p = 0.013) and superolateral cartilage score (adjusted odds ratio (aOR) 1.03, 95% confidence interval (CI): 1.01 to 1.06, p < 0.01). In female sub-elite football players, greater hip external rotation strength was associated with lateral cartilage defects (aOR 1.61, 95%CI: 1.05 to 2.48, p = 0.03) and higher cartilage total score (aIRR 1.25, 95%CI: 1.01 to 1.66, p = 0.042). A one-repetition increase in one-leg rise performance was related to lower odds of superomedial cartilage defects (aOR 0.96, 95%CI: 0.94 to 0.99, p < 0.01). CONCLUSIONS: Overall, there were few associations between peak isometric hip muscle strength and overall hip cartilage defects. It is possible that other factors may have relevance in sub-elite football players. Additional studies are needed to support or refute our findings that higher one leg rise performance was associated with reduced superomedial cartilage defect severity and greater hip extension strength was related to higher cartilage defect severity scores.
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Cartilagem Articular , Articulação do Quadril , Imageamento por Ressonância Magnética , Força Muscular , Futebol , Humanos , Masculino , Feminino , Força Muscular/fisiologia , Adulto , Estudos Transversais , Cartilagem Articular/diagnóstico por imagem , Cartilagem Articular/fisiopatologia , Adulto Jovem , Articulação do Quadril/fisiopatologia , Articulação do Quadril/diagnóstico por imagem , Virilha/fisiopatologia , Artralgia/fisiopatologia , Osteoartrite do Quadril/fisiopatologia , Osteoartrite do Quadril/diagnóstico por imagem , AdolescenteRESUMO
BACKGROUND: Developmental dysplasia of the hip (DDH) is common in performing artists and other young active individuals and involves abnormalities in bony morphology of the acetabulum and proximal femur that can negatively impact walking biomechanics, muscular strength, quality of life, and sleep. Rehabilitation for hip-related conditions should target known modifiable impairments such as hip muscle strength, though a reliable method of assessment in this population remains unclear. OBJECTIVE: To determine the inter- and intra-rater reliability of hip muscle strength assessments using handheld dynamometry (HHD) in young active circus artists with DDH. METHODS: Reliability of hip strength in all planes was assessed using HHD in 21 adult performing circus arts students (mean age 21.3 yrs [3.2]; 13 M, 5 F, 3 NB) with symptomatic radiologically and clinically diagnosed hip dysplasia. The reliability of average peak force and absolute peak force were expressed for each position tested. Reliability was assessed using intraclass correlation coefficients (ICC) with standard error of measurement (SEM) and minimal detectable change (MDC) values calculated to improve clinical interpretability. RESULTS: Good to excellent inter-rater reliability resulted for all hip muscle strength testing positions, ICC=0.88 (95%CI 0.70 to 0.95) to ICC=0.97 (0.92 to 0.99), except average peak hip flexion strength, ICC=0.71 (0.28 to 0.88). Absolute peak hip abduction, ICC=0.77 (0.16 to 0.94), and adduction strength, ICC=0.72 (-0.55 to 0.92), demonstrated the lowest intra-rater reliability. Transverse plane strength measures (rotation) produced the lowest SEM and MDC values followed by the frontal plane (abduction/adduction) and sagittal plane (flexion/extension). CONCLUSION: HHD is an appropriate and reliable method to assess hip muscle strength in circus artists with DDH.
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Força Muscular , Humanos , Força Muscular/fisiologia , Reprodutibilidade dos Testes , Feminino , Masculino , Adulto Jovem , Articulação do Quadril/fisiopatologia , Dinamômetro de Força Muscular , Adulto , Displasia do Desenvolvimento do Quadril/fisiopatologiaRESUMO
OBJECTIVE: To compare early hip osteoarthritis (OA) features on magnetic resonance imaging (MRI) in high-impact athletes with and without hip and/or groin pain, and to evaluate associations between early hip OA features, the International Hip Outcome Tool (iHOT33) and Copenhagen Hip and Groin Outcome Score (HAGOS). DESIGN: This case-control study evaluated data of the femoroacetabular impingement and hip osteoarthritis cohort (FORCe). One hundred and eighty-two symptomatic (hip and/or groin pain >6 months and positive flexion-adduction-internal-rotation (FADIR) test) and 55 pain-free high-impact athletes (soccer or Australian football (AF)) without definite radiographic hip OA underwent hip MRI. The Scoring Hip Osteoarthritis with MRI (SHOMRI) method quantified and graded the severity of OA features. Each participant completed the iHOT33 and HAGOS. RESULTS: Hip and/or groin pain was associated with higher total SHOMRI (0-96) (mean difference 1.4, 95% CI: 0.7-2.2), labral score (adjusted incidence rate ratio (aIRR) 1.33, 95% CI: 1.1-1.6). Differences in prevalence of cartilage defects, labral tears and paralabral cysts between symptomatic and pain-free participants were inconclusive. There was a lower prevalence of effusion-synovitis in symptomatic participants when compared to pain-free participants (adjusted odds ratio (aOR) 0.46 (95% CI: 0.3-0.8). Early hip OA features were not associated with iHOT33 or HAGOS. CONCLUSIONS: A complex and poorly understood relationship exists between hip and/or groin pain and early hip OA features present on MRI in high-impact athletes without radiographic OA. Hip and/or groin pain was associated with higher SHOMRI and labral scores.
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Artralgia , Atletas , Impacto Femoroacetabular , Osteoartrite do Quadril , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Artralgia/diagnóstico por imagem , Artralgia/fisiopatologia , Austrália , Estudos de Casos e Controles , Impacto Femoroacetabular/diagnóstico por imagem , Impacto Femoroacetabular/fisiopatologia , Virilha , Imageamento por Ressonância Magnética , Osteoartrite do Quadril/diagnóstico por imagem , Futebol , Sinovite/diagnóstico por imagem , Sinovite/fisiopatologia , Esportes de EquipeRESUMO
OBJECTIVE: To synthesise and evaluate the current evidence investigating muscle size and composition in non-inflammatory articular hip pathology. METHODS: A systematic review of five electronic databases, using three concepts; articular hip pathology (e.g., osteoarthritis (OA)); hip muscles; and outcomes (e.g., muscle size and adiposity) was undertaken. Studies addressing non-inflammatory or non-traumatic articular hip pain, using measures of muscle size and adiposity were included and appraised for risk of bias. Data was extracted to calculate standardised mean differences (SMD) and pooled where possible for meta-analysis. RESULTS: Thirteen cross-sectional studies were included; all studies measured muscle size and 5/13 measured adiposity. In OA, there was low to very low quality evidence of no difference in hip muscle size, compared with matched controls. In unilateral OA, there was low to very low quality evidence of smaller size in gluteus minimus (SMD -0.38; 95% confidence interval (CI) -0.74, -0.01), gluteus medius (-0.44; 95% CI: -0.83, -0.05) and gluteus maximus (-0.39; 95% CI: -0.75, -0.02) muscles in the symptomatic limb. Individual studies demonstrated non-uniform changes in muscle size in OA. No significant difference was observed in muscle size in other pathologies or in adiposity for any group. CONCLUSION: There is some low quality evidence that specific hip muscles are smaller in unilateral hip OA. Variation in the magnitude of differences indicate changes in size are not uniform across all muscles or stage of pathology. Studies in larger cohorts investigating muscle size and composition across the spectrum of articular pathologies are required to clarify these findings.
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Luxação do Quadril/patologia , Músculo Esquelético/patologia , Osteoartrite do Quadril/patologia , Adiposidade , Viés , Luxação do Quadril/fisiopatologia , Articulação do Quadril/patologia , Humanos , Osteoartrite do Quadril/fisiopatologiaRESUMO
The Rorschach has been demonstrated as a suitable tool for investigating otherwise hidden psychological aspects of sex offenders: sex-related responses are more common. The present paper looks at the established tendency of some clients to minimise their overall Rorschach responding, the linking of this response restraint to particular Rorschach profiles, and the sparse but consistent literature which casts doubt on the proposition that Examiner enthusiasm will cause the minimising client to provide more responses which divulge additional information. In the case of sex offenders, with so much to hide, it is proposed that there may be extensive filtering of responses even among those giving more than "normal" sex-related responses. "What the client did not say", and the corresponding "missing" Rorschach responses in the case of sex offenders is discussed in the light of an individual case: (a sex offender with undue interest in young boys' penii) where "sex-like" images were specifically targeted, but never named as such. The exciting prospect of inferring what the client could have said and thus generating the content of missing responses, whether or not response filtering produced numerical minimisation, must be balanced against the risk of naked men and women (and their genitalia) representing nothing more than an artefact of the clinician's own making--"ce qui n' est pas le cas".
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Teste de Rorschach , Delitos Sexuais/psicologia , Feminino , Identidade de Gênero , Humanos , Luxemburgo , Masculino , Psicometria , Reprodutibilidade dos Testes , Comportamento SexualRESUMO
OBJECTIVES: Explore associations between peak hip strength in football players with hip/groin pain and healthy controls. DESIGN: Cross-sectional study. METHODS: Male and female sub-elite football players (soccer and Australian football) with hip/groin pain >6-month duration and players without hip/groin pain were recruited across Melbourne and Brisbane, Australia. Demographic information and two questionnaires; the Copenhagen Hip and Groin Outcome Score and the International Hip Outcome Tool 33 were collected. Hand-held dynamometry was used to measure isometric hip strength for flexion, extension, abduction, adduction, internal rotation, and external rotation. Linear mixed effects models were used to compare strength measures between groups. RESULTS: 190 football players with hip/groin pain (mean⯱â¯standard deviation age, 27.8⯱â¯6.3â¯years) and 64 controls (age, 27.3⯱â¯5.6â¯years) were included in this study. Of these, 291 symptomatic limbs and 128 control limbs were used for analyses. Symptomatic players had lower peak hip adduction (adjusted mean differenceâ¯=â¯-0.18: 95â¯% confidence interval -0.27 to -0.08, Pâ¯:â¯0.001), external rotation (-0.06: 95â¯% confidence interval -0.09 to -0.02, Pâ¯:â¯0.003), and internal rotation strength (-0.06: 95â¯% confidence interval -0.10 to -0.03, Pâ¯:â¯0.001) compared to controls. A sport-specific interaction was observed for hip abduction strength. When separated by football code, abduction strength was lower in symptomatic Australian football players compared to their same sport peers (-0.20: 95â¯% confidence interval -0.33 to -0.06, Pâ¯:â¯0.004), but not in symptomatic soccer players (-0.05: 95â¯% confidence interval -0.15 to 0.06, Pâ¯:â¯0.382). CONCLUSIONS: Hip adduction, internal rotation, and external rotation strength appears lower in football players with hip/groin pain independent of sex and football code. Hip abduction strength was lower in symptomatic Australian football players but not in soccer players.
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Objective: To explore the relationship between radiographic hip shape and features of early hip osteoarthritis (OA) on magnetic resonance imaging (MRI) in young male and female football players without radiographic hip OA. Design: We used baseline data from a cohort of symptomatic and asymptomatic football players aged 18-50 years. Hip shape was assessed on anteroposterior radiographs with statistical shape modeling (SSM) for men and women separately. Cartilage defects and labral tears were graded using the Scoring Hip Osteoarthritis with MRI (SHOMRI) system. We used logistic regression with generalized estimating equations to estimate associations between each hip shape variant, called shape modes, and cartilage defects or labral tears. Results: We included 229 participants (446 hips, 77.4% male). For each sex, 15 shape modes were analyzed. In men, three shape modes were associated with cartilage defects: adjusted odds ratios (aOR) 0.75 (95%CI 0.58-0.97) per standard deviation (SD) for mode 1; 1.34 (95%CI 1.05-1.69) per SD for mode 12; and 0.61 (95%CI 0.48-0.78) per SD for mode 15; and one also with labral tears: aOR 1.30 (95%CI 1.01-1.69) per SD for mode 12. These modes generally represented variations in the femoral neck and subtypes of cam morphology, with and without pincer morphology. For women, there was no evidence for associations with the outcomes. Conclusions: Several hip shape variants were associated with cartilage defects on MRI in young male football players. Specifically, one subtype of cam morphology was associated with both cartilage defects and labral tears. Hip shape was not associated with early OA features in women.
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OBJECTIVES: Determine physiotherapists' (i) awareness of physical activity, and exercise prescription guidelines; (ii) perceived role, knowledge, confidence, skills and training in prescribing and progressing aerobic exercise and resistance training to people with musculoskeletal pain; (iii) professional development preferences; and (iv) perceived influences of external factors on exercise prescription for people with musculoskeletal pain. DESIGN: Multi-national cross-sectional survey. METHODS: An open online survey was developed specifically for this study. RESULTS: 1,352 physiotherapists from 56 countries participated. The majority of respondents correctly stated physical activity guidelines for adults (60%) and children (53%), but only 37% correctly stated guidelines for older adults. Eleven percent and 16% could name an accepted guideline for aerobic exercise and resistance training, respectively. Most agreed their role included prescribing aerobic exercise (75%) and resistance training (89%). Fewer reported they had the confidence, training or skills to prescribe aerobic exercise (38-50%) and resistance training (49-70%). Workshops were the most preferred (44%) professional development option. Most respondents believed appointment scheduling and access to equipment and professional development (62-79%) affected their ability to prescribe effective exercise. CONCLUSION: Many physiotherapists lack knowledge and training to provide physical activity advice, and to prescribe aerobic exercise and resistance training to people with musculoskeletal pain.
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Terapia por Exercício , Dor Musculoesquelética/reabilitação , Fisioterapeutas/educação , Competência Profissional , Estudos Transversais , Humanos , Prescrições , Inquéritos e QuestionáriosRESUMO
Seven flocks of chickens were raised in groups from weeks 5 to 9 after hatching. Initially the groups had the same number of chickens but they di0ered in population density. The number of birds that survived to week 9 was strongly related to the initial population density.
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Comportamento Animal , População , Aves Domésticas , AnimaisRESUMO
This report introduces some aspects of our current basic research focus on the unique metabolic pathways within the melanocyte. Using this approach, we hope to gain a better understanding of the pathophysiology of malignant melanoma and develop early laboratory diagnostic tests for this disease. Specifically, we will discuss that: 1) the synthesis of pheomelanin is markedly increased in malignant melanoma and dysplastic melanocytic nevi; 2) high levels of metabolites of pheomelanin and eumelanin can be detected in the urine and blood of patients with metastatic melanoma; 3) this release of melanin metabolites appears to correlate with tumor thickness and tumor load, including the extent of metastasis; 4) the synthesis of melanosomal proteins also becomes aberrant in malignant melanoma; and 5) this abnormal melanosome synthesis can be utilized in the identification of antigenic epitopes that are uniquely expressed in malignant melanoma. We believe that this synthesis and secretion of abnormal melanin pigment and melanosomal proteins (human melanosome-specific antigen) would be useful for the development of early laboratory diagnostic and monitoring tools for malignant melanoma. In addition, we also report the detection of pheomelanin component in "normal" unexposed skin; however, the relative amount of pheomelanin in the skin does not reflect hair color (e.g., red hair). The nature of this pheomelanin component in the skin needs to be further clarified.
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Biomarcadores/análise , Melaninas/análise , Melanócitos/química , Melanoma/química , Proteínas/análise , Animais , Diferenciação Celular , Humanos , Melanócitos/citologiaRESUMO
Experimental evidence is reviewed for the implication in aversive learning of the catecholamines, in particular noradrenaline and dopamine and the pituitary-adrenocortical system, in particular adrenocorticotrophic hormone and corticosterone. Depending on task difficulty peripheral neural noradrenaline may be an important factor in aversive learning whereas brain catecholamines are important regardless of task difficulty. The adrenocortical system, as indexed by plasma levels of corticosterone, is also implicated in complex aversive tasks. To date, no convincing empirical evidence exists for a link mechanism between the brain catecholamine system and the adrenocortical system following aversive learning. Earlier behavior theories of aversive learning are reformulated in the light of more recent findings on neuroregulation.
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Aprendizagem da Esquiva/fisiologia , Catecolaminas/fisiologia , 11-Hidroxicorticosteroides/fisiologia , Hormônio Adrenocorticotrópico/fisiologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Sistema Nervoso Central/fisiologia , Condicionamento Operante/fisiologia , Dopamina/fisiologia , Medo/fisiologia , Hidroxidopaminas/farmacologia , Norepinefrina/fisiologia , Nervos Periféricos/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Ratos , Sistema Nervoso Simpático/fisiologiaRESUMO
Melanocyte-stimulating hormone (MSH) has putative adaptive significance in all forms of species where it is present. In mammals the polypeptide chain influences learning, memory and attention. Chemically MSH shares the first 13 (alpha-MSH) or the first 18 or 22 (beta-MSH) amino acids with adrenocorticotropic hormone (ACTH), even though the mechanisms of secretion and behavioral effects are often quite different. The still shorter peptide chain MSH/ACH4-10 demonstrates significant melanotropic and behavioral actions of alpha-MSH without showing any steroidogenic effect. Behaviorally, alpha-MSH and MSH/ACTH analogues (MSH/ACTH4-9 and MSH/ACTH4-10 influence the parameters of learning, attention and memory in both human and infrahuman subjects. Alpha-MSH has also been reported to increase sensitivity and augment arousal mechanisms in the CNS. Alpha-MSH has been observed to increase and sustain novelty-induced defecation, and this behavior was found to be accompanied by a concomitant decrease in whole brain DA and NE levels in both intact and hypophysectomized rats exposed daily to a test box. The behavioral effects of alpha-MSH may be partially modulated by the enhanced cyclic-AMP activity in the CNS observed after MSH administration. MSH also seems to be working in conjunction with the hypothalamic tripeptide MIF-1 and the pineal hormone melatonin, both of which can affect the release of MSH from the pituitary. Recent evidence suggests that MSH is counterbalancing against and complementing with the effects of endorphins, specifically beta-endorphin (61-91 chain of beta-LPH), in maintaining learning and attentive behaviors.
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Comportamento Animal/fisiologia , Hormônios Estimuladores de Melanócitos/fisiologia , Hormônio Adrenocorticotrópico/fisiologia , Animais , Comportamento Apetitivo/fisiologia , Nível de Alerta/fisiologia , Atenção/fisiologia , Aprendizagem da Esquiva/fisiologia , Encéfalo/fisiologia , Fenômenos Químicos , Química , Aprendizagem por Discriminação/fisiologia , Eletroencefalografia , Potenciais Evocados , Humanos , Sistema Hipotálamo-Hipofisário/fisiologia , Rememoração Mental/fisiologia , Glândula Pineal/fisiologia , Transmissão SinápticaRESUMO
Insulin-like growth factors (IGFs) are peptide mitogens, structurally related to insulin, whose biological actions in the CNS are incompletely known. The retina is largely uncharacterized with respect to IGF receptors. We, therefore, studied IGF receptors in bovine and murine retinal tissues by immunohistochemistry, autoradiographic localization, and affinity labeling. Notable IGF-II receptor immunoreactivity was found in retinal pigment epithelium (RPE), with intermediate levels in choroid, low levels in the inner and outer plexiform layers and outer nuclear layer, and very low levels in other regions. Autoradiographic localization using [125I]IGF-II confirmed the IGF-II receptor immunohistochemistry. Autoradiographic localization using [125I]IGF-I labeled the nuclear layers and the photoreceptor region. Affinity labeling disclosed differences in the apparent mol wt of IGF-I and IGF-II receptors from bovine eye tissues and those from liver and brain. IGF-I receptor alpha-subunits (the IGF-binding subunit) migrated at: liver, 139,000; brain, 125,000; RPE, 125,000 and 135,000 (two sizes); and retina, 125,000 and 135,000. IGF-II receptors migrated at: liver, 245,000; brain, 235,000; RPE, 240,000; and retina, 230,000. We conclude that mammalian retina contains both IGF-I and -II receptors, which differ from those found in other tissues and have a characteristic spatial distribution within the retina.
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Fator de Crescimento Insulin-Like II/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Receptores de Superfície Celular/análise , Retina/metabolismo , Somatomedinas/metabolismo , Animais , Autorradiografia , Bovinos , Membranas Intracelulares/metabolismo , Radioisótopos do Iodo , Masculino , Microssomos/metabolismo , Peso Molecular , Ratos , Ratos Endogâmicos , Receptores de Superfície Celular/isolamento & purificação , Receptores de Superfície Celular/metabolismo , Receptores de SomatomedinaRESUMO
Levamisole injection resulted in an elevation in the T helper:T suppressor (H:S) subset ratio in rats at 24 h after injection due to a selective depression in the cytotoxic/suppressor subset. This response was shown to be conditionable and could be reenlisted 14 days later by re-exposure to the conditioned stimulus. Rats were conditioned using a taste aversion paradigm by pairing levamisole injection with the novel taste of saccharin. Fourteen days later, after a second exposure to saccharin without levamisole injection, H:S ratios were elevated in the blood of these rats compared to control rats injected with levamisole but fed normal water or rats fed saccharin without levamisole injection.
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Comportamento Animal/fisiologia , Linfócitos T/classificação , Adjuvantes Imunológicos/administração & dosagem , Animais , Injeções Subcutâneas , Levamisol/administração & dosagem , Levamisol/imunologia , Ratos , Ratos Endogâmicos , Sacarina/administração & dosagem , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Auxiliares-Indutores/citologia , Linfócitos T Reguladores/citologia , Paladar/fisiologiaRESUMO
Synthetic arginine vasotocin (AVT) was infused into rat brains either by intraventricular administration or by local infusion on the pineal body. Subsequently, exploratory behavior was analyzed in a hole board. The behavioral effects induced by this peptide were dependent on the time of day, i. e. the light or the dark phase. High intraventricular doses (0.4 microgram) administered during the light phase altered exploratory activity such that the number of hole visits was increased, while the duration of each visit was decreased; lower doses produced no effect. In contrast, during the dark phase peripineal infusion of AVT (10(-4) pg) attenuated the number of hole visits and increased the mean duration of the visits. The strongest effects were obtained with peripineal applications during the dark phase. This treatment also resulted in significantly lowered levels of pineal melatonin.
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Comportamento Exploratório/efeitos dos fármacos , Vasotocina/farmacologia , Animais , Ritmo Circadiano/efeitos dos fármacos , Relação Dose-Resposta a Droga , Injeções Intraventriculares , Masculino , Glândula Pineal/efeitos dos fármacos , Ratos , Ratos EndogâmicosRESUMO
A classical Pavlovian paradigm pairing an olfactory cue with allergen challenge for a single training trial was used to produce conditioned histamine release and conditioned nasal airflow decrease in seasonal allergic rhinitis sufferers. There was no conditioned increase in subjective symptoms. Histamine release and airflow decrease showed evidence of extinction by a second test trial. A second study comparing the effects of the number of training trials showed that three training trials produced greater histamine release and airflow decrease than a single training trial, suggesting stronger effects with additional training.
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Hipersensibilidade Imediata , Hipersensibilidade , Rinite Alérgica Sazonal , HumanosRESUMO
Two experiments were performed to evaluate the effects of Arginine Vasotocin (AVT) on open field behavior, who brain monoamines and plasma corticosterone. In Experiment 1 rats treated with AVT compared to controls displayed an increased initial latency to move, less postural freezing and increased exploration of the central area of the open field. In Experiment 2 it was found that AVT significantly elevated whole brain 5-HT levels (Experiment 2A) without altering levels of dopamine or norepinephrine. Plasma corticosterone was significantly decreased by AVT treatment (Experiment 2B).
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Encéfalo/metabolismo , Corticosterona/sangue , Comportamento Exploratório/efeitos dos fármacos , Serotonina/metabolismo , Vasotocina/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Dopamina/metabolismo , Masculino , Norepinefrina/metabolismo , RatosRESUMO
The pituitary-hypothalamo-pineal complex involving MSH, MIF-I and melatonin has been strongly emphasized in the adaptive mechanism of the animal. A series of experiments was conducted to investigate the effects of alpha-MSH, MIF-I and melatonin on novelty-induced defecation, step-down activity, plasma 11-OHCS levels and whole brain DA and NE concentrations over days of novelty X drug treatment. alpha-MSH consistently enhanced and sustained novelty-induced defecation, increased plasma 11-OHCS levels in the resting intact rats and in the novelty exposed hypophysectomized (hypox) rats, and decreased brain DA and NE levels in intact, hypox and sham-hypox rats. MSH did not increase plasma 11-OHCS in intact and sham-hypox rats during exposure to novelty. MIF-I significantly habituated novelty-induced defecation and increased brain DA and NE levels over 5 days of drug X novelty treatment. Melatonin, on the other hand, inhibited novelty-induced defecation, decreased plasma 11-OHCS and increased brain DA level over 5 days of melatonin X novelty treatment. MSH, MIF-I or melatonin did not show any significant effect on the step-down activity of the rats. The results suggest the possibility that central CAs may be implicated in the behavioral changes observed after alpha-MSH, MIF-I and melatonin administration and in the interaction of the pituitary-hypothalamo-pineal complex involving MSH, MIF-I and melatonin.
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11-Hidroxicorticosteroides/sangue , Química Encefálica/efeitos dos fármacos , Catecolaminas/metabolismo , Defecação/efeitos dos fármacos , Hormônio Inibidor da Liberação de MSH/farmacologia , Hormônios Estimuladores de Melanócitos/farmacologia , Melatonina/farmacologia , Animais , Meio Ambiente , Hipofisectomia , Masculino , RatosRESUMO
The present study shows tha alpha-MSH facilitates the acquisition and delays the extinction of a Passive Avoidance Response (PAR) in the hypox animals. MSH exacerbates PA-induced defecation in both hypox and sham-hypox animals. Hypox and sham-hypox animals treated with MSH do not differ on PAR or on PA-induced defecation. Melatonin, on the other hand, has no significant effect on PAR in hypox rats, but retards acquisition and facilitates extinction of the PAR in sham-hypox rats. Melatonin also inhibits PA-induced defecation in sham-hypox rats. Sham-hypox and hypox rats treated with Melatonin do not differ on PAR learning, retention (Extinction) and PA-induced defecation. MSH and Melatonin also seem to have opposite effects on plasma 11-OHCS levels measured at the end of PAR extinction. MSH increases plasma 11-OHCS in hypox rats, whereas Melatonin decreases plasma 11-OHCS in sham-hypox rats. Melatonin does not lower further the very low level of plasma 11-OHCS in hypox rats.
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11-Hidroxicorticosteroides/sangue , Aprendizagem da Esquiva/efeitos dos fármacos , Defecação/efeitos dos fármacos , Hormônios Estimuladores de Melanócitos/farmacologia , Melatonina/farmacologia , Animais , Hipofisectomia , Cinética , Masculino , RatosRESUMO
Pinealectomized (PX) and sham animals were administered either AVT (1 ng/kg) or vehicle (1 ml H20). Boxing-kicking-biting episodes were significantly reduced by administration of AVT, F(1,21) = 8.09, p less than 0.009. Crawling under behavior was increased in PXH20 animals (p less than 0.05). Non-aggressive rearing was decreased by administration of AVT, F(1,21) = 4.75, p less than 0.04. These results are in agreement with previous findings that AVT lowers emotionality-arousal. Results are discussed in terms of vasotonergic effects on central monoamines.