Factors affecting executive function performance of Brazilian elderly in the Stroop test

Aging is related to a decrease in physiological abilities, especially cognitive functions. To unravel further evidence of age-related cognitive decline, we analyzed which physical and functional variables are predictors of cognitive performance in a sample of 498 Brazilian elderly (67.26% women). To do so, we used the Stroop test as a tool to evaluate executive functions and the General functional fitness index (GFFI) to evaluate the functional fitness of the participants. A linear regression analysis revealed that female sex (β=-0.097; t=-2.286; P=0.023), younger age (β=0.205; t=4.606; P<0.0001), more years of education (β=-0.280; t=-6.358; P<0.0001), and higher GFFI (β=-0.101; t=-2.347; P<0.02) were predictors of better cognitive performance. Body mass index (kg/m2) and nutritional status (underweight, eutrophic, overweight, or obese) were not predictors of cognitive performance. Interestingly, among the GFFI tasks, muscle strength influenced the test execution time, both in upper and lower limbs (elbow flexion: β=-0.201; t=-4.672; P<0.0001; sit-to-stand: β=-0.125; t=-2.580; P<0.01). Our findings showed that: 1) women performed the Stroop test faster than men; 2) the older the person, the lower was the cognitive performance; 3) the higher the education, the better the test execution time; and 4) higher scores in the GFFI were associated with a better performance in the Stroop test. Therefore, gender, age, education, and functional fitness and capacity were predictors of cognitive performance in the elderly.

Fine needle aspiration cytology in feline skeletal muscle as a diagnostic tool for extramedullary plasmacytoma / Citologia aspirativa por agulha fina no músculo esquelético felino como ferramenta diagnóstica para o plasmocitoma extramedular

Extramedullary noncutaneous plasmacytoma (ENP) is a myeloproliferative disorder of plasma cells that rarely affects cats. This paper describes an ENP case revealed by fine needle aspiration cytology (FNAC) of the mass in the skeletal muscle of an 8-month-old, male, mixed breed cat, which had a nodule in the left hind limb. The rapid immunoassay test confirmed the presence of feline leukemia virus (FeLV). The animal necropsy macroscopically showed the nodule came from the semimembranosus muscle. Histopathological examination ratified the cytological findings. Thus, this paper alerts to the existence of plasmacytoma located in the skeletal muscle of feline species. FNAC is a quick and efficient method for diagnosis of ENP.(AU)

O plasmocitoma extramedular (PEM) não cutâneo é um distúrbio mieloproliferativo de plasmócitos que raramente acomete felinos. Este trabalho descreve um caso de PEM no músculo esquelético de um gato, macho, sem raça definida, de oito meses de idade, que apresentava um aumento de volume no membro pélvico esquerdo. A citologia aspirativa por agulha fina (CAAF) da massa revelou tratar-se de PEM. O teste imunoenzimático rápido confirmou a presença do vírus da leucemia felina (FeLV). Na necropsia do animal, macroscopicamente, percebeu-se que o nódulo era originário do músculo semimembranoso. O exame histopatológico ratificou os achados citológicos. Desta forma, alerta-se para a existência de plasmocitoma com localização em músculo esquelético na espécie felina, sendo a CAAF um método alternativo rápido e eficaz para o seu diagnóstico.(AU)

Differential response to gepirone but not to chlordiazepoxide in malnourished rats subjected to learned helplessness

The learned helplessness (LH) paradigm is characterized by learning deficits resulting from inescapable events. The aims of the present study were to determine if protein-calorie malnutrition (PCM) alters learning deficits induced by LH and if the neurochemical changes induced by malnutrition alter the reactivity to treatment with GABA-ergic and serotonergic drugs during LH. Well-nourished (W) and PCM Wistar rats (61 days old) were exposed or not to inescapable shocks (IS) and treated with gepirone (GEP, 0.0-7.5 mg/kg, intraperitoneally, N = 128) or chlordiazepoxide (0.0-7.5 mg/kg, intraperitoneally, N = 128) 72 h later, 30 min before the test session (30 trials of escape learning). The results showed that rats exposed to IS had higher escape latency than non-exposed rats (12.6 ± 2.2 vs 4.4 ± 0.8 s) and that malnutrition increased learning impairment produced by LH. GEP increased the escape latency of W animals exposed or non-exposed to IS, but did not affect the response of PCM animals, while chlordiazepoxide reduced the escape deficit of both W and PCM rats. The data suggest that PCM animals were more sensitive to the impairment produced by LH and that PCM led to neurochemical changes in the serotonergic system, resulting in hyporeactivity to the anxiogenic effects of GEP in the LH paradigm.

The interaction of housing condition and acute immobilization stress on the elevated plus-maze behaviors of protein-malnourished rats

Protein malnutrition induces structural, neurochemical and functional alterations in the central nervous system, leading to behavioral alterations. In the present study, we used the elevated plus-maze (EPM) as a measure of anxiety to evaluate the interaction between acute immobilization and housing conditions on the behavior of malnourished rats. Pups (6 males and 2 females) were fed by Wistar lactating dams receiving a 6 percent (undernourished) or 16 percent (well-nourished) protein diet. After weaning, the animals continued to receive the same diets ad libitum until 49 days of age when they started to receive a regular lab chow diet. From weaning to the end of the tests on day 70, the animals were housed under two different conditions, i.e., individual or in groups of three. On the 69th day, half of the animals were submitted to immobilization for 2 h, while the other half were undisturbed, and both groups were tested 24 h later for 5 min in the EPM. Independent of other factors, protein malnutrition increased, while immobilization and social isolation per se decreased, EPM exploration. Analysis of the interaction of diet vs immobilization vs housing conditions showed that the increased EPM exploration presented by the malnourished group was reversed by acute immobilization in animals reared in groups but not in animals reared individually. The interaction between immobilization and housing conditions suggests that living for a long time in social isolation is sufficiently stressful to reduce the responses to another anxiogenic procedure (immobilization), while living in groups prompts the animals to react to acute stress. Thus, it is suggested that housing condition can modulate the effects of an anxiogenic procedure on behavioral responses of malnourished rats in the EPM.

Ethological analysis of mother-pup interactions and other behavioral reactions in rats: effects of malnutrition and tactile stimulation of the pups

Mother-pup interaction, as well as other behavioral reactions were studied during the lactation period in 24 litters of Wistar rats and their dams fed either a 16 percent (control - C; 12 litters) or a 6 percent (malnourished - M; 12 litters) protein diet. The diets were isocaloric. Throughout lactation there was a 36.4 percent weight loss of M dams and a 63 percent body weight deficit in the M pups when compared to control pups. During this period, half of the litters were exposed daily to additional tactile stimulation (CS or MS), while the other half were submitted to normal rearing conditions (CN or MN). The tactile stimulation of pups (handling) consisted of holding the animal in one hand and gently touching the dorsal part of the animal's body with the fingers for 3 min. A special camera and a time-lapse video were used to record litter behavior in their home cages. Starting at 6 p.m. and ending at 6 a.m., on days 3, 6, 12, 15, 18 and 21 of lactation, photos were taken at 4-s intervals. An increase in the frequency (154.88 + or - 16.19) and duration (455.86 + or - 18.05 min) of suckling was observed throughout the lactation period in all groups compared to birth day (frequency 24.88 + or - 2.37 and duration 376.76 + or - 21.01 min), but the frequency was higher in the C (84.96 +- 8.52) than in the M group (43.13 + or - 4.37); however, the M group (470.2 + or - 11.87 min) spent more time suckling as compared with the C group (393.67 + or - 13.09 min). The M dams showed a decreased frequency of resting position throughout the lactation period (6.5 + or- 2.48) compared to birth day (25.42 + or - 7.74). Pups from the C group were more frequently observed separated (73.02 + or - 4.38) and interacting (258.99 + or - 20.61) more with their mothers than the M pups (separated 66.94 + or - 5.5 and interacting 165.72 + or - 12.05). Tactile stimulation did not interact with diet condition, showing that the kind of stimulation used in the present study did not lead to recovery from the changes induced by protein malnutrition. The changes in mother-pup interaction produced by protein malnutrition of both may represent retardation in neuromotor development and a higher dependence of the pups on their mothers. These changes may represent an important means of energy saving and heat maintenance in malnourished pups

Response threshold to aversive stimulated early protein-malnourished rats

Two animal models of pain were used to study the effects of short-term protein malnutrition and environmental stimulation on the response threshold to aversive stimuli. Eighty male Wistar rats were used. Half of the pups were submitted to malnutrition by feeding their mothers a 6 per cent protein diet from 0 to 21 days of age while the mothers of the other half (controls) were well nourished, receiving 16 per cent protein. From 22 to 70 days all rats were fed commercial lab chow. Half of the animals in the malnourished and control groups were maintained under stimulating conditions, including a 3-min daily handling from 0 to 70 days and an enriched living cage after weaning. The other half was reared in a standard living cage. At 70 days, independent groups of rats were exposed to the shock threshold or to the tail-flick test. The results showed lower body and brain weights in malnourished rats when compared with controls at weaning and testing. In the shock threshold test the malnourished animals were more sensitive to electric shock and environmental stimulation increased the shock threshold. No differences due to diet or environmental stimulation were found in the tail-flick procedure. These results demonstrate that protein malnutrition imposed only during the lactation period is efficient in inducing hyperreactivity to electric, shock and that environmental stimulation attenuates the differences in shock threshold produced by protein malnutrition.

Acquisition and extinction of jumping, two-way shuttle-box and bar press avoidance responses in malnourished rats: effects of shock intensity

1. In order to investigate the role of avoidance response and shock intensity in avoidance learning in malnourished rats, three avoidance responses (jumping, two-way shuttle-box and bar press) and three shock intensities (0.4, 0.6 and 1.0 mA) were used. Independent groups of 6 rats were used for each response topography and shock intensity. 2. Malnourished male Wistar rats were suckled by mothers fed a 12 percent casein diet during the lactation period (0-21 days of age) while the mothers of well-nourished controls received a 25//casein diet. After weaning (21 st day), all animals received a commercial lab chow diet until 70 days of age, when the avoidance training started. 3. Malnutrition did not affect the acquisiton of the avoidance response, but malnourisheed groups required more trials to extinguish jumping and two-way shuttle-box. During the acquisitiion phase all animals learned the jump response faster in comparison to bar press and shuttle-box avoidance responses. Both groups in the acquisition phase responded faster with 1.0 mA when compared to lower intensities (0.6 and 0.4 mA). The malnourished animals showed lower latency of avoidance in the jumping response when compared with well-nourished animals. During the extinction phase there was a significant effect of diet, response topography and shock intensity in the latency to respond and trials to criterion. The increased resistance to extinctio in malnourished rats was particularly evident with 1.0 mA in the two-way shuttle-box response. 4. These results suggest that contradictory data related to the acquisition of the avoidance response in malnourished animals cannot be attributed to response topography or variations in shock intensity. Furthermore, our results also indicate that resistance to extinction and latency to respond are appropriate for detecting differences between well-nourished and malnourished animals

Comparison of the effects of lab chow and casein diets based on body and brain development of rats

1. In order to study the effects of protein quantity and quality on development, Wistar rats were submitted to four different diets during lactation and post-lactation periods. Three isocaloric diets were utilized with 6 per cent (M), 16 per cent (W16) and 20 per cent (W20) of protein (casein), and the fourth diet (C) consisted of a commercial lab chow containing 22 per cent protein. 2. During the lactation and post-lactation periods the body weights of dams and pups were recorded weekly. On the 49th day of age (21 days of suckling and 28 days of ad libitum chow), all animals were sacrificed and the brains removed and weighed. 3. Dams from all groups increased food intake during the lactation period, but dams of the M group consumed a lower amount of diet as compared with other groups. Only the body weight of M dams was affected by diet during the lactation period, but the body weight of pups from the M and C groups was lower than in the other two groups. At 49 days of age C and M pups showed a significantly lower brain weight compared with W16 and W20 pups. 4. Thus, a commercial lab chow diet does not promote normal body and brain development as compared with balanced diets containing 16 or 20 per cent protein. These results emphasize the need for further studies in order to evaluate other biological and behavioral parameters that might be altered by a lab chow diet

Early malnutrition alters the effect of chlordiazepoxide on inhibitory avoidance

In order to study the functional consequences of brain changes caused by early malnutrition, rats were fed a protein-deficient diet from birth until 49 days of age and a balanced diet from day 50 to day 70. The animals were submitted to a step-down inhibitory avoidance task and to the flinch-jump nociceptive test at 49 and 70 days of age. Malnourished rats showed longer step-down latencies and lower flinch and junp theresholds than eutrophic animals. Chlordiazepoxide (5 mg/Kg, ip) shortened step-down latency of well-nourished rats, whereas it failed to do so in malnourished rats. Since well-nourished animals also became resistant to chlordiazepoxide when tested with a higher shock intensity, generating avoidance latencies comparable to those of malnourished animals, we conclude that the drug resistance induced by malnutrition may be secondary to enhanced pain sensitivity and/or reactivity