Rômulo Dias Novaes

Usual gait speed assessment in middle-aged and elderly Brazilian subjects

OBJECTIVES To evaluate the usual gait speed of asymptomatic adult and elderly Brazilians with a 10-meter walk test and to compare the results with foreign reference values. METHODS Seventy-nine asymptomatic volunteers ≥40 years old of both genders were assessed. After anamnesis, anthropometry and the application of a habitual physical activity questionnaire, the volunteers were submitted to a 10-meter walk test at usual speed by means of which gait speed, the number of steps and length of stride were calculated. RESULTS Except for age, all study variables were significantly lower in women. Subjects ≥70 years old presented a significantly lower gait speed than subjects between 40 and 49 years old and between 50 and 59 in both men (1.09±0.18 m/s, 1.35±0.11 m/s and 1.34±0.22 m/s, respectively) and women (1.02±0,10 m/s, 1.27±0.20 m/s and 1.27±0,15 m/s), respectively). Gait speed showed moderate correlations with age (r=-0.41, p<0.001) and height (r=0.35, p=0.001). After multiple regression analysis, age and gender were selected as relevant attributes of gait speed in that they explained 24.6% of this variable. The gait speed values in this study were significantly lower than foreign reference values (p<0.05). CONCLUSIONS The gait speed presented age-related decline and values significantly lower than those described for foreign populations. This finding indicates the need for comprehensive investigation of gait speed reference values for the Brazilian population.

Bark extract of Bathysa cuspidata attenuates extra-pulmonary acute lung injury induced by paraquat and reduces mortality in rats

This study investigated the effect of the bark extract of Bathysa cuspidata on paraquat (PQ)‐induced extra‐pulmonary acute lung injury (ALI) and mortality in rats. ALI was induced with a single dose of PQ (30 mg/kg, i.p.), and animals were treated with B. cuspidata extract (200 and 400 mg/kg). Analyses were conducted of survival, cell migration, lung oedema, malondialdehyde, proteins carbonyls, catalase, superoxide dismutase, histopathology and the stereology of lung tissue. Rats exposed to PQ and treated with 200 and 400 mg of the extract presented lower mortality (20% and 30%), compared with PQ alone group (50%). Furthermore, lung oedema, septal thickening, alveolar collapse, haemorrhage, cell migration, malondialdehyde and proteins carbonyl levels decreased, and catalase and superoxide dismutase activity were maintained. These results show that the bark extract of B. cuspidata reduced PQ‐induced extra‐pulmonary ALI and mortality in rats and suggest that these effects may be associated with the inhibition of oxidative damage.

Trypanosoma cruzi infection induces morphological reorganization of the myocardium parenchyma and stroma, and modifies the mechanical properties of atrial and ventricular cardiomyocytes in rats

BACKGROUND This study investigates morphofunctional adaptations of the heart stroma and parenchyma in rats that are chronically infected with Trypanosoma cruzi. METHODS Four-month-old male Wistar rats were randomized into control (n=14) and infected (n=14) groups. Infected animals were inoculated with T. cruzi Y strain. After 9 weeks, the animals were euthanized, and the right atrium (RA) and left ventricle (LV) were removed for biochemical, stereological, and cardiomyocyte mechanical analyses. RESULTS Infected animals presented cardiomyocyte atrophy and myocardial fibrosis. For these animals, the total volume, length, surface area, and cross-sectional area of cardiomyocytes were significantly reduced, and the total interstitial and collagen volumes were significantly increased in the RA and LV compared to the controls. The total volume and length of blood vessels were significantly increased in the LV, and the total blood vessel surface area was significantly higher in the RA of infected animals. RA and LV cardiomyocytes from infected animals exhibited a significant reduction in cell shortening (43.02% and 24.98%, respectively), prolongation of the time to the peak of contraction (17.09%) and the time to half relaxation (23.68%) compared to non-infected animals. Lipid hydroperoxides, but not mineral concentrations, were significantly increased in the RA and LV from infected animals, showing an inverse correlation with cell shortening. CONCLUSIONS T. cruzi infection induces global structural remodeling of the RA and LV in rats. This remodeling coexists with cardiomyocyte contractility dysfunction, which is possibly related to the abnormal organization of the myocardial stroma and increased cellular lipid peroxidation.

Equações de referência para a predição da força de preensão manual em brasileiros de meia idade e idosos

O objetivo deste estudo foi avaliar os valores normais da forca de preensao manual do membro superior dominante (FPM-D) e nao dominante (FPM-ND) em sujeitos de meia idade e idosos assintomaticos e elaborar equacoes de referencia para a predicao da FPM. Foram investigados 54 voluntarios (51,9% homens) com idade >50 anos, medindo-se massa corporal, estatura e perimetria do braco direito e esquerdo, e calculando-se o indice de massa corporal. A FPM-D e FPM -ND foram avaliadas por dinamometria mecânica. O indice de atividade fisica habitual (IAF) foi avaliado pelo questionario de Baecke. A FPM-D foi superior a FPM-ND em ambos os sexos e em todas as idades (p<0,05). Foram encontradas correlacoes significativas entre a FPM e idade, estatura, massa corporal e perimetria do braco. As melhores equacoes de referencia foram as seguintes: FPM-Dkgf =39,996 - (0,382 x idadeanos)+(0,174 x pesokg)+(13,628 x sexohomens=1;mulheres=0) (R2ajustado=0,677); e FPM-NDkgf=44,968- (0,420 x idadeanos)+(0,110 x pesokg)+(9,274 x sexohomens=1;mulheres=0) (R2ajustado=0,546) A diferenca consistente entre a FPM-D e FPM-ND torna necessario o uso de dados normativos especificos para cada mao. Atributos simples de serem obtidos, tais como idade, estatura, massa corporal, perimetria do braco e sexo, podem pois prever adequadamente os valores esperados da FPM para adultos e idosos assintomaticos.

Effect of Bark Extract of Bathysa Cuspidata on Hepatic Oxidative Damage and Blood Glucose Kinetics in Rats Exposed to Paraquat

This study investigated the effect of bark extract of Bathysa cuspidata on hepatic oxidative damage and blood glucose kinetics in rats exposed to paraquat. Wistar rats were exposed to a single dose of paraquat (30 mg/kg, i.p.) and treated with an ethanolic extract of Bathysa cuspidata (200 and 400 mg/kg). Analyses were conducted of liver edema, blood glucose, serum transaminases, alkaline phosphatase, collagen, malondialdehyde, catalase, superoxide dismutase, and histomorphometry. In the animals intoxicated with paraquat and treated with 400 mg/kg of extract, edema, hypertrophy of the nucleus of hepatocytes, serum transaminases, alkaline phosphatase, and malondialdehyde levels decreased significantly (p < .05). Catalase and superoxide dismutase activity, the number of hepatocytes per unit volume, and the glycogen proportion were maintained. The increase followed by progressive reduction of blood glucose observed in paraquat-exposed groups was significantly attenuated in the group treated with 400 mg/kg of extract (p < .05). Phytochemical analysis of the extract revealed the presence of flavonoids, proanthocyanidins, and phenolic compounds. The bark extract of Bathysa cuspidata was able to inhibit large variations in blood glucose and reduce hepatic damage in rats exposed to paraquat. This finding suggests a contribution of the extract in reducing lipid peroxidation and the morphofunctional damage to the liver parenchyma.

Hepatoprotective effect of Bathysa cuspidata in a murine model of severe toxic liver injury

The objective of this study was to investigate the hepatoprotective effect of a bark extract of Bathysa cuspidata extract (BCE) in a murine model of severe liver injury induced by carbon tetrachloride (CCl4). Forty‐two Wistar rats were randomized into six groups of seven animals each: Group 1(G1): CCl4; Group 2 (G2): dimethyl sulfoxide (DMSO) + CCl4; Group 3 (G3): BCE 400 mg/kg alone; Group 4 (G4): BCE 200 mg/kg + CCl4; Group 5 (G5): BCE 400 mg/kg + CCl4; Group 6 (G6): DMSO alone. The extract was administered by gavage for 18 days beginning 6 days prior to the first application of CCl4. After completing CCl4 administration, the animals were euthanized. The animals in G1, G2, G4 and G5 experienced significant body weight loss and had an increased liver somatic index compared with G3 and G6 (P < 0.05). A significant reduction in serum aspartate and alanine transaminase and gamma‐glutamyl transferase (P < 0.05) and a significant increase in the activity of the anti‐oxidant enzyme superoxide dismutase were found in G5 (P < 0.05). Lower proportions of cellular necrosis and lipid droplets were found in the livers of animals in G4 and G5 compared with G1 and G2 (P < 0.05). These results confirm the marked hepatoprotective activity of the bark extract of Bathysa cuspidata in severe injuries induced by CCl4 in rats and suggest that this effect may be associated with the inhibition of oxidative damage.

Long-lasting morphofunctional remodelling of liver parenchyma and stroma after a single exposure to low and moderate doses of cadmium in rats

Frequent exposure to cadmium (Cd) in low doses is common; however, the long‐lasting effects of this exposure are still poorly understood. Therefore in this study we have evaluated long‐lasting hepatic morphofunctional adaptations in rats exposed to low and moderate doses of Cd. Five experimental groups were tested: control (0.9% saline) and other four receiving single intraperitoneal doses of 0.67, 0.74, 0.86 and 1.1 mg of Cd/kg. The animals were killed after eight weeks and the following parameters were analysed: biometrics, oedema, Cd bio‐accumulation, collagen, glycogen, lipid droplets, superoxide dismutase (SOD) and catalase (CAT), serum transaminases, liver histopathology and stereology. In all groups exposed to Cd there was significant increase in SOD and CAT activities, ALP levels, proportion of binucleated hepatocytes, nuclei/cytoplasm ratio, macrophages (Kupffer cells) and collagen fibres. In these groups, glycogen accumulation by hepatocytes and the proportion of sinusoidal capillaries were significantly reduced compared with controls. The liver somatic index was increased, and liver oedema was evident in animals exposed to higher dose of Cd. Areas of necrosis were found in animals exposed to the three highest doses. These results indicate that Cd is an extremely toxic bioactive heavy metal, which even at low doses is able to disrupt liver homeostasis. At low and moderate doses, Cd exposure induces morphofunctional pathological remodelling of the hepatic stroma and parenchyma, which remain active after eight weeks. In response to injury, the liver tissue triggers a reactive process by enhancing activation of antioxidant enzymes and collagenogenesis.

Naringin accelerates the regression of pre-neoplastic lesions and the colorectal structural reorganization in a murine model of chemical carcinogenesis

The aim of this study was to investigate the effect of Naringin on pre-neoplastic colorectal lesions induced by chemical carcinogen in rats. Female Wistar rats weighing 130.8±27.1 g received weekly one subcutaneous injection of 1,2-dimethylhydrazine (DMH, 20 mg/kg) for 10 weeks. The animals were divided into 5 groups with 6 animals in each group. Group 1: 0.9% saline; Group 2: DMH+0.9% saline; Group 3: DMH+Naringin (10 mg/kg); Group 4: DMH+Naringin (100 mg/kg); Group 5: DMH+Naringin (200 mg/kg). G2 and G3 showed a significant increase in ACF number, AgNOR/nucleus and mitosis compared to G1. G4 and G5 presented a significant reduction in these parameters compared to G2. The number of cells producing acidic and neutral mucins, red blood cells and the level of antioxidant minerals, such as copper, magnesium, selenium and zinc, were significantly reduced in G2 and G3, but similar in G4 and G5 compared to G1. Naringin, especially at 200 mg/kg, was effective in reducing the number of pre-neoplastic lesions in rats exposed to DMH. Some of these effects may be due to reduction in cellular proliferation and tissue levels of iron together with the recovery of antioxidant mineral levels induced by this flavonoid.

Exercise training prior to myocardial infarction attenuates cardiac deterioration and cardiomyocyte dysfunction in rats

OBJECTIVES: The present study was performed to investigate 1) whether aerobic exercise training prior to myocardial infarction would prevent cardiac dysfunction and structural deterioration and 2) whether the potential cardiac benefits of aerobic exercise training would be associated with preserved morphological and contractile properties of cardiomyocytes in post-infarct remodeled myocardium. METHODS: Male Wistar rats underwent an aerobic exercise training protocol for eight weeks. The rats were then assigned to sham surgery (SHAM), sedentary lifestyle and myocardial infarction or exercise training and myocardial infarction groups and were evaluated 15 days after the surgery. Left ventricular tissue was analyzed histologically, and the contractile function of isolated myocytes was measured. Students t-test was used to analyze infarct size and ventricular wall thickness, and the other parameters were analyzed by the Kruskal-Wallis test followed by Dunns test or a one-way analysis of variance followed by Tukeys test (p<0.05). RESULTS: Myocardial infarctions in exercise-trained animals resulted in a smaller myocardial infarction extension, a thicker infarcted wall and less collagen accumulation as compared to myocardial infarctions in sedentary animals. Myocardial infarction-induced left ventricular dilation and cardiac dysfunction, as evaluated by +dP/dt and -dP/dt, were both prevented by previous aerobic exercise training. Moreover, aerobic exercise training preserved cardiac myocyte shortening, improved the maximum shortening and relengthening velocities in infarcted hearts and enhanced responsiveness to calcium. CONCLUSION: Previous aerobic exercise training attenuated the cardiac dysfunction and structural deterioration promoted by myocardial infarction, and such benefits were associated with preserved cardiomyocyte morphological and contractile properties.

Effects of Trypanosoma cruzi infection on myocardial morphology, single cardiomyocyte contractile function and exercise tolerance in rats

The aim of this study was to investigate the effects of Trypanosoma cruzi (T. cruzi) infection on myocardial morphology, single cardiomyocyte contractile function and exercise tolerance in rats. Adult Wistar rats were randomized into control (n = 14) and infected (n = 14) groups. Infected animals were inoculated with T. cruzi Y strain (300,000 trypomastigotes/50 g body weight). After 9 weeks, the animals were subjected to a treadmill running protocol. Then, the right atrium (RA) and left ventricle (LV) were removed for morphological and cell contractile evaluation. The infected animals exhibited a significant reduction in distance travelled, total time to fatigue and workload. In addition, these animals had hypertrophy, increased myocardial cellularity, and an increase in the proportion of collagen and blood vessels. RA and LV myocytes from infected animals showed marked contractile dysfunction under basal conditions and a reduced contractile response to β‐adrenergic stimulation. The workload of infected animals was correlated closely with the amplitude of cell shortening of RA and LV myocytes. T. cruzi infection influenced the myocardial morphology and the mechanical properties of RA and LV single myocytes negatively and reduced exercise tolerance. Single cardiomyocyte contractile dysfunction could constitute an additional mechanism of cardiac impairment and reduced exercise tolerance in this infection.