971 resultados para Hypothesis test


Relevância:

20.00% 20.00%

Publicador:

Resumo:

It is well established that morphine inhibits maternal behaviors. Previous studies by our group have shown activation of the rostrolateral periaqueductal gray (rlPAG) upon inhibition-intended subcutaneous injections of morphine. In this context, we demonstrated that a single naloxone infusion into the rlPAG, following this opioid-induced inhibition, reactivated maternal behaviors. Since these data were obtained by using peripheral morphine injections, the present study was designed to test whether morphine injected directly into the rlPAG would affect maternal behaviors. Our hypothesis that morphine acting through the rlPAG would disrupt maternal behaviors was confirmed with a local infusion of morphine. The mothers showed shorter latency for locomotor behavior to explore the home cage (P = 0.049). Inhibition was especially evident regarding retrieving (P = 0.002), nest building (P = 0.05) and full maternal behavior (P = 0.023). These results support the view that opioidergic transmission plays a behaviorally meaningful inhibitory role in the rostrolateral PAG.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Standardized olfactory tests are now available to quantitatively assess disorders of olfaction. A Brazilian-Portuguese version of the University of Pennsylvania Smell Identification Test (UPSIT) is currently being developed specifically for the Brazilian population. The most recent Brazilian-Portuguese version of the UPSIT (UPSIT-Br2) was administered to 88 Brazilian subjects who had no history of neurological or otorhinolaryngological disease. UPSIT-Br2 scores decreased with age, were lower in men than in women, and were lower in subjects with lower income. The degree to which the poorer performance of subjects with lower socio-economic status reflects lack of familiarity with test items is not known. Although this version of the UPSIT provides a sensitive and useful test of smell function for the Brazilian population, a revision of some test items is needed to achieve comparable norms to those found using the North American UPSIT in the United States.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE: Because autonomic dysfunction has been found to lead to cardiometabolic disorders and because studies have reported that simvastatin treatment has neuroprotective effects, the objective of the present study was to investigate the effects of simvastatin treatment on cardiovascular and autonomic changes in fructose-fed female rats. METHODS: Female Wistar rats were divided into three groups: controls (n=8), fructose (n=8), and fructose+ simvastatin (n=8). Fructose overload was induced by supplementing the drinking water with fructose (100 mg/L, 18 wks). Simvastatin treatment (5 mg/kg/day for 2 wks) was performed by gavage. The arterial pressure was recorded using a data acquisition system. Autonomic control was evaluated by pharmacological blockade. RESULTS: Fructose overload induced an increase in the fasting blood glucose and triglyceride levels and insulin resistance. The constant rate of glucose disappearance during the insulin intolerance test was reduced in the fructose group (3.4+ 0.32%/min) relative to that in the control group (4.4+ 0.29%/min). Fructose+simvastatin rats exhibited increased insulin sensitivity (5.4+0.66%/min). The fructose and fructose+simvastatin groups demonstrated an increase in the mean arterial pressure compared with controls rats (fructose: 124+2 mmHg and fructose+simvastatin: 126 + 3 mmHg vs. controls: 112 + 2 mmHg). The sympathetic effect was enhanced in the fructose group (73 + 7 bpm) compared with that in the control (48 + 7 bpm) and fructose+simvastatin groups (31+8 bpm). The vagal effect was increased in fructose+simvastatin animals (84 + 7 bpm) compared with that in control (49 + 9 bpm) and fructose animals (46+5 bpm). CONCLUSION: Simvastatin treatment improved insulin sensitivity and cardiac autonomic control in an experimental model of metabolic syndrome in female rats. These effects were independent of the improvements in the classical plasma lipid profile and of reductions in arterial pressure. These results support the hypothesis that statins reduce the cardiometabolic risk in females with metabolic syndrome.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4%) men and 241 (54.6%) women (mean age: 38.7 ± 11.0 years) were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05). Sixteen (6.7%) women and 9 (4.5%) men demonstrated ST-segment upslope ≥0.15 mV or downslope ≥0.10 mV; the difference was not statistically significant. Age increase of one year added 4% to the chance of upsloping of segment ST ≥0.15 mV or downsloping of segment ST ≥0.1 mV (P = 0.03; risk ratio = 1.040, 95% confidence interval (CI) = 1.002-1.080). Heart rate recovery was higher in women (P < 0.05). The chance of women showing an increase of systolic blood pressure ≤30 mmHg was 85% higher (P = 0.01; risk ratio = 1.85, 95%CI = 1.1-3.05). No significant difference in the frequency of ST-T wave changes was observed between men and women. Other differences may be related to different physical conditioning.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

FUNDAMENTO: A recuperação da freqüência cardíaca após o eletrocardiograma de esforço em esteira ergométrica é modulada pelo sistema nervoso autônomo. A análise da variabilidade da freqüência cardíaca (VFC) pode fornecer informações valiosas sobre o controle do sistema nervoso autônomo sobre o sistema cardiovascular. OBJETIVO: O objetivo deste estudo foi testar a hipótese de associação entre a recuperação da freqüência cardíaca após teste de esforço em esteira ergométrica e a variabilidade da freqüência cardíaca. MÉTODOS: Foram estudamos 485 indivíduos sem evidência de cardiopatia com média de idade de 42± 12,1 (faixa etária de 15 a 82) anos, 281 (57.9%) dos quais do sexo feminino, submetidos a um teste de esforço em esteira ergométrica e avaliação da VFC nos domínios do tempo (SDNN, SDANN, SDNNi, rMSSD e pNN50) e da freqüência (LF, HF, VLF e razão LF/HF) durante monitoramento eletrocardiográfico ambulatorial de 24 horas. RESULTADOS: A recuperação da freqüência cardíaca foi de 30 ± 12 batimentos no 1º minuto e 52± 13 batimentos no 2º minuto após o exercício. Os indivíduos mais jovens de recuperaram mais rápido do 2º ao 5º minuto após o exercício (r = 0,19-0,35, P < 0,05). As mulheres se recuperaram mais rápido que os homens (4 ± 1,1 batimentos a menos no 1º minuto, p < 0,001; 5,7 ± 1,2 batimentos a menos no 2º minuto, p < 0,01; e 4,1± 1,1 batimentos a menos no 3º minuto, p < 0.001). Não houve correlação significante entre a recuperação da freqüência cardíaca e a VFC no 1º e 2º minutos após o exercício. Os índices SDNN, SDANN, SDNNi, rMSSD e pNN50 só apresentaram uma correlação significante com a recuperação da freqüência cardíaca no 3º e 4º minutos. CONCLUSÃO: A hipótese de associação entre recuperação da freqüência cardíaca e VFC em 24 horas nos primeiros dois minutos após o exercício não foi comprovada neste estudo. A recuperação da freqüência cardíaca foi associada com idade e sexo.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD50/0.03mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0% for the Desmodus rotundus isolate; 50.0% for dog and Nyctinomops laticaudatus isolates; 40.0% for Artibeus lituratus isolate; 9.5% Molossus molossus isolate; and 5.2% for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this study was to evaluate the ability of the BANA Test to detect different levels of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia or their combinations in subgingival samples at the initial diagnosis and after periodontal therapy. Periodontal sites with probing depths between 5-7 mm and clinical attachment level between 5-10 mm, from 53 subjects with chronic periodontitis, were sampled in four periods: initial diagnosis (T0), immediately (T1), 45 (T2) and 60 days (T3) after scaling and root planing. BANA Test and Checkerboard DNA-DNA hybridization identified red complex species in the subgingival biofilm. In all experimental periods, the highest frequencies of score 2 (Checkerboard DNA-DNA hybridization) for P. gingivalis, T. denticola and T. forsythia were observed when strong enzymatic activity (BANA) was present (p < 0.01). The best agreement was observed at initial diagnosis. The BANA Test sensitivity was 95.54% (T0), 65.18% (T1), 65.22% (T2) and 50.26% (T3). The specificity values were 12.24% (T0), 57.38% (T1), 46.27% (T2) and 53.48% (T3). The BANA Test is more effective for the detection of red complex pathogens when the bacterial levels are high, i.e. in the initial diagnosis of chronic periodontitis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

It is well known that carbohydrate (CHO) supplementation can improve performance in endurance exercises through several mechanisms such as maintenance of glycemia and sparing endogenous glycogen as well as the possibility of a central nervous-system action. Some studies have emerged in recent years in order to test the hypothesis of ergogenic action via central nervous system. Recent studies have demonstrated that CHO mouth rinse can lead to improved performance of cyclists, and this may be associated with the activation of brain areas linked to motivation and reward. These findings have already been replicated in other endurance modalities, such as running. This alternative seems to be an attractive nutritional tool to improve endurance exercise performance.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose: This study investigated the energy system contributions of judo athletes to the Special Judo Fitness Test (SJFT). Methods: Fourteen male judo athletes performed the SJFT, which comprised three periods of judo activity (A = 15 s, B and C = 30 s) interspersed with 10 s rest intervals. During this test, one athlete threw two others positioned 6 m from each other using the ippon-seoi-nage technique. The fractions of the aerobic, anaerobic alactic and anaerobic lactic systems were calculated based on oxygen uptake, the fast component of excess postexercise oxygen uptake, and changes in net blood lactate, respectively. The contribution of the three energy systems was compared using a repeated measures analysis of variance and Bonferroni's multiple comparisons test. Compound symmetry, or sphericity, was determined by Mauchly's test. A level of significance of 5% (P < .05) was adopted in all analyses. Results: The alactic energy system presented a higher (F = 20.9; P < .001; power observed = 1.0) contribution (86.8 +/- 23.6 kJ; 42.3 +/- 5.9%) during the test when compared with both aerobic (57.1 +/- 11.3 kJ; 28.2 +/- 2.9%) and lactic (58.9 +/- 12.1 kJ; 29.5 +/- 6.2%) energy systems (P < .001 for both comparisons). Conclusions: The higher alactic contribution seems to be a consequence of the high-intensity efforts performed during the test, and its intermittent nature. Thus, when using the SJFT, coaches are evaluating mainly their athletes' anaerobic alactic system, which can be considered to be the most predominant system contributing to the actions (techniques) performed in the match.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study aimed to describe and compare the ventilation behavior during an incremental test utilizing three mathematical models and to compare the feature of ventilation curve fitted by the best mathematical model between aerobically trained (TR) and untrained ( UT) men. Thirty five subjects underwent a treadmill test with 1 km.h(-1) increases every minute until exhaustion. Ventilation averages of 20 seconds were plotted against time and fitted by: bi-segmental regression model (2SRM); three-segmental regression model (3SRM); and growth exponential model (GEM). Residual sum of squares (RSS) and mean square error (MSE) were calculated for each model. The correlations between peak VO2 (VO2PEAK), peak speed (Speed(PEAK)), ventilatory threshold identified by the best model (VT2SRM) and the first derivative calculated for workloads below (moderate intensity) and above (heavy intensity) VT2SRM were calculated. The RSS and MSE for GEM were significantly higher (p < 0.01) than for 2SRM and 3SRM in pooled data and in UT, but no significant difference was observed among the mathematical models in TR. In the pooled data, the first derivative of moderate intensities showed significant negative correlations with VT2SRM (r = -0.58; p < 0.01) and Speed(PEAK) (r = -0.46; p < 0.05) while the first derivative of heavy intensities showed significant negative correlation with VT2SRM (r = -0.43; p < 0.05). In UT group the first derivative of moderate intensities showed significant negative correlations with VT2SRM (r = -0.65; p < 0.05) and Speed(PEAK) (r = -0.61; p < 0.05), while the first derivative of heavy intensities showed significant negative correlation with VT2SRM (r= -0.73; p < 0.01), Speed(PEAK) (r = -0.73; p < 0.01) and VO2PEAK (r = -0.61; p < 0.05) in TR group. The ventilation behavior during incremental treadmill test tends to show only one threshold. UT subjects showed a slower ventilation increase during moderate intensities while TR subjects showed a slower ventilation increase during heavy intensities.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Stingless bees exhibit extraordinary variation in nest architecture within and among species. To test for phylogenetic association of behavioral traits for species of the Neotropical stingless bee genus Trigona s.s., a phylogenetic hypothesis was generated by combining sequence data of 24 taxa from one mitochondrial (16S rRNA) and four nuclear gene fragments (long-wavelength rhodopsin copy 1 (opsin), elongation factor-1 alpha copy F2, arginine kinase, and 28S rRNA). Fifteen characteristics of the nest architecture were coded and tested for phylogenetic association. Several characters have significant phylogenetic signal, including type of nesting substrate, nest construction material, and hemipterophily, the tending of hemipteroid insects in exchange for sugar excretions. Phylogenetic independent habits encountered in Trigona s.s. include coprophily and necrophagy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The citrus greening (or huanglongbing) disease has caused serious problems in citrus crops around the world. An early diagnostic method to detect this malady is needed due to the rapid dissemination of Candidatus Liberibacter asiaticus (CLas) in the field. This analytical study investigated the fluorescence responses of leaves from healthy citrus plants and those inoculated with CLas by images from a stereomicroscope and also evaluated their potential for the early diagnosis of the infection caused by this bacterium. The plants were measured monthly, and the evolution of the bacteria on inoculated plants was monitored by real-time quantitative polymerase chain reaction (RT-qPCR) amplification of CLas sequences. A statistical method was used to analyse the data. The selection of variables from histograms of colours (colourgrams) of the images was optimized using a paired Student's t-test. The intensity of counts for green colours from images of fluorescence had clearly minor variations for healthy plants than diseased ones. The darker green colours were the indicators of healthy plants and the light colours for the diseased. The method of fluorescence images is novel for fingerprinting healthy and diseased plants and provides an alternative to the current method represented by PCR and visual inspection. A new, non-subjective pattern of analysis and a non-destructive method has been introduced that can minimize the time and costs of analyses.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Objective To test the hypothesis that 12-lead ECG QRS scoring quantifies myocardial scar and correlates with disease severity in Chagas' heart disease. Design Patients underwent 12-lead ECG for QRS scoring and cardiac magnetic resonance with late gadolinium enhancement (CMR-LGE) to assess myocardial scar. Setting University of Sao Paulo Medical School, Sao Paulo, Brazil. Patients 44 Seropositive patients with Chagas' disease without a history of myocardial infarction and at low risk for coronary artery disease. Main outcome measures Correlation between QRS score, CMR-LGE scar size and left ventricular ejection fraction. Relation between QRS score, heart failure (HF) class and history of ventricular tachycardia (VT). Results QRS score correlated directly with CMR-LGE scar size (R=0.69, p<0.0001) and inversely with left ventricular ejection fraction (R=-0.54, p=0.0002), which remained significant in the subgroup with conduction defects. Patients with class II or III HF had significantly higher QRS scores than those with class I HF (5.1 +/- 3.4 vs 2.1 +/- 3.1 QRS points (p=0.002)) and patients with a history of VT had significantly higher QRS scores than those without a history of VT (5.3 +/- 3.2% vs 2.6 +/- 3.4 QRS points (p=0.02)). A QRS score >= 2 points had particularly good sensitivity and specificity (95% and 83%, respectively) for prediction of large CMR-LGE, and a QRS score >= 7 points had particularly high specificity (92% and 89%, respectively) for predicting significant left ventricular dysfunction and history of VT. Conclusions The wide availability of 12-lead ECG makes it an attractive screening tool and may enhance clinical risk stratification of patients at risk for more severe, symptomatic Chagas' heart disease.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Subclinical hypothyroidism (SCH) has been associated with atherosclerosis, but the abnormalities in plasma lipids that can contribute to atherogenesis are not prominent. The aim of this study was to test the hypothesis that patients with normocholesterolemic, normotriglyceridemic SCH display abnormalities in plasma lipid metabolism not detected in routine laboratory tests including abnormalities in the intravascular metabolism of triglyceride-rich lipoproteins, lipid transfers to high-density lipoprotein (HDL), and paraoxonase 1 activity. The impact of levothyroxine (LT4) treatment and euthyroidism in these parameters was also tested. Methods: The study included 12 SCH women and 10 matched controls. Plasma kinetics of an artificial triglyceride-rich emulsion labeled with radioactive triglycerides and cholesteryl esters as well as in vitro transfer of four lipids from an artificial donor nanoemulsion to HDL were determined at baseline in both groups and after 4 months of euthyroidism in the SCH group. Results: Fractional clearance rates of triglycerides (SCH 0.035 +/- 0.016 min(-1), controls 0.029 +/- 0.013 min(-1), p=0.336) and cholesteryl esters (SCH 0.009 +/- 0.007 min(-1), controls 0.009 +/- 0.009 min(-1), p=0.906) were equal in SCH and controls and were unchanged by LT4 treatment and euthyroidism in patients with SCH, suggesting that lipolysis and remnant removal of triglyceride-rich lipoproteins were normal. Transfer of triglycerides to HDL (SCH 3.6 +/- 0.48%, controls 4.7 +/- 0.63%, p=0.001) and phospholipids (SCH 16.2 +/- 3.58%, controls 21.2 +/- 3.32%, p=0.004) was reduced when compared with controls. After LT4 treatment, transfers increased and achieved normal values. Transfer of free and esterified cholesterol to HDL, HDL particle size, and paraoxonase 1 activity were similar to controls and were unchanged by treatment. Conclusions: Although intravascular metabolism of triglyceride-rich lipoproteins was normal, patients with SCH showed abnormalities in HDL metabolism that were reversed by LT4 treatment and achievement of euthyroidism.