RESUMO
We describe how hookworms interact with their human hosts by comparing lymphocyte phenotyping, proliferative responses, and cytokine and chemokine secretion patterns in adults who are either mono-infected with Necator americanus or egg-negative controls resident in an area of high transmission in Brazil. Cellular immune responses against crude hookworm antigen extracts from different developmental stages were evaluated simultaneously. Principal component analysis (PCA) was used to reduce the standardized immune responses. Random effects multivariate regression was then used to investigate whether principal components (PC) differ between the two groups once potential confounders and effect modifiers have been accounted for. Although hookworm patients had reduced percentages of T and B cells, they had higher levels of activated CD4(+) T and CD19(+) B cells. This state of 'immune activation' coincided with lower proliferative responses, especially to third-stage larval antigen. Cytokine levels in mono-infected adults were also lower and characterized by a mixed Th1/Th2-type profile. Excretory/secretory antigen from adult worms was a potent modulator of the immune response, resulting in diminished TNF-alpha and IL-10 secretion in peripheral blood mononuclear cells (PBMC) from hookworm infected patients. We propose that the longevity of hookworms in their human hosts results from a stage-specific, down-modulation of the immune response.
Assuntos
Estágios do Ciclo de Vida , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos/imunologia , Necator americanus/crescimento & desenvolvimento , Necator americanus/imunologia , Necatoríase/imunologia , Adolescente , Adulto , Idoso , Animais , Antígenos de Helmintos/imunologia , Brasil , Citocinas/biossíntese , Feminino , Interações Hospedeiro-Parasita , Humanos , Masculino , Pessoa de Meia-Idade , Necator americanus/patogenicidade , Necatoríase/parasitologia , Análise de Componente PrincipalRESUMO
Synthetic A-type carbonated apatite prepared in controlled conditions was irradiated at room temperature with 60Co gamma rays. The ESR spectrum was associated to axial CO2- and orthorhombic CO3- species. Radicals used as dose markers in biological apatites are long-lived paramagnetic species. The stability of the post-irradiation signal of A-type apatite was investigated for almost 2 years. Measurements showed variations in the spectra attributed to unstable CO3- species, which can be eliminated by thermal treatments at 100 degrees C for 24 h. Results indicated the potential use of an A-type carbonated apatite as a dosemeter.
Assuntos
Apatitas/química , Apatitas/efeitos da radiação , Carbonatos , Campos Eletromagnéticos , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Radiometria/métodos , Reprodutibilidade dos TestesRESUMO
Selection of food can be affected by several factors, and with the method of self-selection, qualitative changes in nutritional balance may be detected. The goal of the present study was to evaluate feeding preferences in weaning rats using three macronutrients (protein, carbohydrate, and fat), through a free-choice method, evaluating the alteration in their feeding patterns as compared with the previous nutritional status during the early lactation period. We analyzed the effects of protein restriction during lactation over the nitrogen balance after the weaning. The dams were assigned to one of two diet conditions (nourished or malnourished). At weaning, two pups from each litter were housed individually in metabolic cages, and they were maintained on self-selection under a free-choice paradigm and were provided with separate sources of macronutrients. The parameter for evaluating the nutritional effectiveness of the diets was nitrogen balance. We observed that protein intake tended to increase and consumption of carbohydrate and fat tended to decrease progressively during the 3 wk of experiment. In selecting their own food, growing rats and malnourished rats consumed a larger amount of protein than the other rats. Nourished rats selecting their diet had a larger nitrogen balance than nourished rats receiving a composed diet; no nitrogen balance difference was found between the self-selecting groups. Rats can choose an adaptive form when recovering from protein malnutrition.
Assuntos
Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Comportamento Alimentar , Lactação/fisiologia , Desnutrição Proteico-Calórica/fisiopatologia , Animais , Carboidratos da Dieta/metabolismo , Gorduras na Dieta/metabolismo , Proteínas Alimentares/metabolismo , Feminino , Preferências Alimentares , Nitrogênio/metabolismo , Necessidades Nutricionais , Desnutrição Proteico-Calórica/metabolismo , Ratos , Ratos WistarRESUMO
It has been shown that environmental stimulation may reduce the damage caused by malnutrition to morphological and behavioural parameters; however, there are no data on the effects of stimulation on the Brainstem Auditory Evoked Potentials (BAEPs). The aim of this study was to evaluate the effects of protein malnutrition, nutritional recovery and environmental stimulation on the BAEPs of the rat. On the first day of life, the animals were divided into Well-nourished (W) and Malnourished (M) groups. At weaning, half the M rats were submitted to nutritional recovery (R) until the test day. All groups were subdivided into Stimulated (S) and Non-Stimulated (N) rats. BAEPs was tested in animals exposed to clicks of 90, 80 and 70 dB of intensity. The BAEPs latencies of waves I, II, III and IV in the left ear were analysed in independent groups of rats on the 14th, 18th, 22nd, 32nd, and 42nd days of age. Statistical analysis showed diet and environmental stimulation interaction on the latencies of waves I, II, III and IV at all tested ages. WN rats showed longer latencies of waves I, II, III and IV than WS rats, and MN rats also showed longer latencies of these waves compared to WN, MS and RN at all tested ages. The results showed that malnutrition caused a delay in the latency of all BAEPs waves in rats of all ages. However, environmental stimulation reduced these latencies, reversing some damage caused by malnutrition. These data suggest that the auditory brainstem pathway is vulnerable to nutritional insults, and its structures show plasticity with environmental stimulation.
Assuntos
Meio Ambiente , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Distúrbios Nutricionais/fisiopatologia , Estimulação Acústica , Animais , Animais Recém-Nascidos/fisiologia , Peso Corporal , Feminino , Lactação/fisiologia , Ratos , Ratos Wistar , Tempo de Reação/fisiologia , DesmameRESUMO
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% (control - C; 12 litters) or a 6% (malnourished - M; 12 litters) protein diet. The diets were isocaloric. Throughout lactation there was a 36.4% weight loss of M dams and a 63% 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 +/- 16.19) and duration (455.86 +/- 18.05 min) of suckling was observed throughout the lactation period in all groups compared to birth day (frequency 24.88 +/- 2.37 and duration 376.76 +/- 21.01 min), but the frequency was higher in the C (84.96 +/- 8.52) than in the M group (43.13 +/- 4.37); however, the M group (470.2 +/- 11.87 min) spent more time suckling as compared with the C group (393.67 +/- 13.09 min). The M dams showed a decreased frequency of resting position throughout the lactation period (6.5 +/- 2.48) compared to birth day (25.42 +/- 7.74). Pups from the C group were more frequently observed separated (73.02 +/- 4.38) and interacting (258.99 +/- 20.61) more with their mothers than the M pups (separated 66.94 +/- 5.5 and interacting 165.72 +/- 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.
Assuntos
Comportamento Animal , Lactação , Desnutrição Proteico-Calórica/fisiopatologia , Tato/fisiologia , Análise de Variância , Animais , Animais Lactentes , Peso Corporal , Feminino , RatosRESUMO
The feeding preference of normal rats (n = 14), malnourished rats (n = 14), and enterectomized rats (n = 16) was determined in a situation of free choice of three complete solid diets which only differed in extent of protein polymerization: intact casein, casein hydrolysate, and an amino acid mixture with a composition similar to that of casein. The animals were housed in metabolic cages for 30 days and allowed to freely choose among the three diets presented simultaneously. All three groups showed an initial preference for the intact casein diet. The control group maintained this preference, whereas the malnourished and enterectomized groups reduced the ingestion of the intact casein diet and increased the ingestion of the amino acid diet. The nitrogen balance, which was always positive in all three groups, was constant in the control group (1.51 +/- 0.26 g) initially higher (1.77 +/- 0.19 g) in the malnourished group, with a subsequent fall (1.13 +/- 0.24 g), and lower in the enterectomized group (0.83 +/- 0.32 g). Although total intake was similar for the control and malnourished groups, the malnourished group presented a higher weight recovery (130.2%). In contrast, the food intake of the enterectomized group was much lower, with a small weight gain. After treatment that impairs the digestive tract, intact casein was the initially preferred nitrogen source, which later tended to be replaced with free amino acids. This change was accompanied by an improvement in nitrogen balance and body weight, especially after protein malnutrition. These data may suggest that, in clinical practice, the use of enteral diets containing fully hydrolyzed protein may be of benefit in terms of the recovery of malnourished patients and of patients with short bowel syndrome.
Assuntos
Caseínas/administração & dosagem , Preferências Alimentares/fisiologia , Deficiência de Proteína/fisiopatologia , Hidrolisados de Proteína/administração & dosagem , Animais , Peso Corporal , Caseínas/química , Dieta , Ingestão de Alimentos , Íleo/cirurgia , Jejuno/cirurgia , Masculino , Hidrolisados de Proteína/química , Ratos , Ratos WistarRESUMO
An increased number of visits and time spent in the open arms of the elevated plus-maze by malnourished rats has been used as indicative of lower anxiety or higher impulsiveness. In order to study how this behavior profile responds to an anxiogenic procedure (short-term social isolation), control (16% protein) and malnourished (6% protein) rats were socially isolated prior to the test in the maze. Litters (dam plus 6 male and 2 female pups) were fed the diets from birth to 49 days of age. From 50 days on, all rats were fed a lab chow diet. Social isolation consists in removing the rats from the group and placing them in individual cages for 2 h before the test. During the test each rat was individually placed on the center of the maze and allowed to explore for 5 min. The results showed higher open arms exploration and lower attempts to enter open arms by the malnourished rats than by the controls. Social isolation decreased open arm exploration and increased time spent on the central platform in control animals, but had no effect on the malnourished rats. The results reinforce the lower anxiety or higher impulsiveness of malnourished rats, as well as the anxiogenic effect of social isolation in control rats. However, the malnourished rats were unresponsive to the anxiogenic effects of social isolation, indicating that protein deficiency early in life not only induces lower anxiety or higher impulsiveness in the maze, but also changes the behavior of these animals in response to another environmentally-induced procedure of anxiety (social isolation).
RESUMO
A complex program of environmental and sensory stimulation was developed to study its potential effects in reversing some of the alterations produced by early protein malnutrition in the brain and behavior of rats. Litters (dam plus 6 male pups) were fed diets containing 8% (malnourished) or 25% (well-nourished) casein. After weaning, the animals were maintained on the same diets as their respective dams until 50 days of age. Environmental stimulation consisted of 3-min daily handling from birth to 50 days of age. Additional stimulation was provided from birth to 50 days of age by rearing the rats in an enriched living cage and exposing the animals to visual, auditory and olfactory stimuli. At 50 days of age the animals were submitted to locomotor and inhibitory avoidance tests. Animals of the same age were sacrificed, the brain removed and divided in telencephalon, brain steam and cerebellum. DNA and RNA were assessed in telencephalon and cerebellum. Protein malnutrition produced brain weight deficits that were partially reversed by environmental stimulation. DNA and RNA levels were reduced by protein malnutrition and increased by environmental stimulation. The behavioral measures showed lower locomotor activity and higher latencies in inhibitory avoidance for malnourished animals as compared to well-nourished animals. Environmental stimulation reduced the aversiveness in the inhibitory avoidance test as showed by lower latencies in the stimulated group of animals. These results suggest that early protein malnutrition impairs brain and behavior of rats and that a complex program of environmental stimulation is beneficial to reverse some of those impairments.
RESUMO
UNLABELLED: The interaction between the effects of different levels of protein malnutrition and environmental stimulation was investigated in young male rats in the elevated plus-maze (EPM). Litters (dam plus 6 male and 2 female pups) were fed a 16% ( CONTROL: C), 10% (Malnourished: M10) or 6% (Malnourished: M6) protein diet. Half of the litters were daily exposed to additional stimulation (CS, MS10 or MS6), while the other half was maintained in normal rearing conditions (CN, MN10 or MN6). The stimulation (handling) consisted of holding the rat in one hand and gently touching the dorsal part of the body with the fingers for 3 min. On the 22nd day of life (weaning), two male pups from each group were tested in the plus-maze. Two male pups continued to receive the same diet as their mothers, and the other two were fed a non-purified lab chow diet until 35 days of age when they were tested in the plus-maze (LN, LS, LN10, LS10, LN6 and LS6 groups). Results showed that environmental stimulation increased open arms exploration both at 22 and 35 days of age, indicating an anxiolytic effect of this procedure. Younger rats (22 days of age) explored significantly more the open arms of the maze as compared with older rats (35 days of age), indicating an increase in anxiety with age. M6 animals showed significantly higher percentages of open arm entries and less frequent attempts to enter open arms in the maze as compared with C and M10 animals. These results suggest that even a short period of protein deficiency can produce alterations in the emotional response of rats in the elevated plus-maze. In addition, the data demonstrated that protein deficiency more severe than 10% is necessary to produce behavior alterations in the EPM test.
RESUMO
Studies on rats maintained on low-protein-calorie diets during the lactation period show that food intake decreases. This process results in weight loss and a delay in litter development. The purpose of the present study was to determine the alterations in food intake, maternal weight and litter growth during lactation when dams were exposed to diets with different levels of protein and carbohydrate. Female Wistar rats receiving one of 4 different diets, A (N = 14), B (N = 14), C (N = 9) and D (N = 9), were used. Diet A contained 16% protein and 66% carbohydrate; diet B, 6% protein and 77% carbohydrate; diet C, 6% protein and 66% carbohydrate; diet D, 16% protein and 56% carbohydrate. Thus, C and D diets were hypocaloric, while A and B were isocaloric. The intake of a low-protein diet in groups B and C affected the weight of dams and litters during the last two weeks of lactation, while the low-calorie diets limited the growth of D litters at 21 days compared with A litters, but had no effect on the weight of D dams. Group B showed an increase in intake during the first five days of lactation, resulting in a behavioral calorie compensation due to the increase in carbohydrate content, but the intake decreased during the last part of lactation. Food intake regulation predominantly involves the recruitment of a variety of peripheral satiety systems that attempt to decrease the central feeding command system.
Assuntos
Peso Corporal , Dieta , Ingestão de Alimentos , Ingestão de Energia , Crescimento , Lactação , Distúrbios Nutricionais , Animais , Feminino , Ratos , Ratos WistarRESUMO
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% protein diet from 0 to 21 days of age while the mothers of the other half (controls) were well nourished, receiving 16% 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.
Assuntos
Terapia Aversiva , Desnutrição Proteico-Calórica/fisiopatologia , Animais , Peso Corporal , Encéfalo/patologia , Masculino , Tamanho do Órgão , Ratos , Ratos WistarRESUMO
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.
Assuntos
Ratos , Animais , Masculino , Recém-Nascido , Terapia Aversiva , Peso Corporal/fisiologia , Encéfalo/fisiologia , /complicações , Ratos WistarRESUMO
The objective of the present study was to determine the consequences of Zn2+ deficiency on the gestational process. The study was conducted on adult Wistar virgin female rats fed isocaloric diets containing 16% protein and different Zn2+ concentrations, i.e., 2 ppm (severe restriction), 6 ppm (moderate restriction), and 20 ppm (control). Rats received the diets and water ad libitum for 7, 14 or 21 days before mating and throughout pregnancy. Survival of dams and pups decreased with increasing Zn2+ restriction and with time of exposure to the deficient diet. Mean survival rate for control dams and pups was 100%, whereas severe restriction (2 ppm for 21 days premating and during pregnancy) resulted in survival rates of 25% and 0 for dams and pups, respectively. Dam and pup survival rates for moderate restriction (6 ppm) for the same period were 83% and 72%, respectively. These results indicate the importance of Zn2+ before and during pregnancy and show that Zn2+ deficiency causes metabolic alterations which impair normal reproductive processes.
Assuntos
Dieta , Prenhez/fisiologia , Zinco/deficiência , Animais , Animais Recém-Nascidos , Peso Corporal , Feminino , Masculino , Gravidez , Ratos , Ratos WistarRESUMO
PURPOSE: To evaluate the early physical conditioning (PC) effect [initiated 15 days after the myocardial revascularization surgery (MRS)] in the functional capacity. METHODS: Twenty-two male patients (mean-age of 52y-o), divided in two groups (A and B, 11 patients each), were studied. Group A started PC 3 months after MRS (phase III), with a training intensity of about 70% of the maximum heart rate reserve, during three months, three sessions per week with one hour duration. Group B started PC 15 days after the MRS (fase II), with a training intensity up to five metabolic unities, three times a week, 1 hour and 15 duration. The post-MRS period of three months was designated as the time I (beginning of fase III) and six months as time 2. Stress test, Kraus-Weber flexibility test, coxo-femural flexibility test (flexion, elevation and abduction) and scapule-umeral flexibility test (flexion, extension and abduction) were applied. RESULTS: The maximum oxygen uptake and the total work increased significantly from time 1 to time 2 in both groups, but there was no significant difference between the two groups, either in time 1 or 2. Flexibility in the Kraus-Weber test and in the scapule-umeral flexibility test when in flexion, were significantly greater in group B than A, in both times (1 and 2). Other flexibility variables studied show no significant difference, neither between the studied groups nor in the times 1 and 2 of evaluation. CONCLUSION: Early PC after MRS increased the value of two variables that measure flexibility. However, it has not increased other flexibilities variables and the aerobic capacity.
Assuntos
Terapia por Exercício/métodos , Capacidade Residual Funcional , Revascularização Miocárdica/reabilitação , Consumo de Oxigênio , Análise de Variância , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Fatores de Tempo , Trabalho RespiratórioRESUMO
Six days old neonate with pulmonary atresia and intact ventricular septum is reported in which a communication was established between the right ventricle and the pulmonary artery. The membraneous atresia was perforated with a special radiofrequency catheter 2F connected to a Hat 200S radiofrequency generator (Osypka). The energy necessary to perforation was 15W. After perforation of the atresia, balloon dilation was performed (balloon diameter: 2, 3, 4mm of coronary angioplasty and 5, 8mm Penta Medi-tech). The valve was completely opened giving the continuity between right ventricle and pulmonary artery.
Assuntos
Ablação por Cateter , Cateterismo , Septos Cardíacos/cirurgia , Atresia Pulmonar/terapia , Angiografia , Eletrocardiografia , Septos Cardíacos/diagnóstico por imagem , Humanos , Recém-Nascido , MasculinoRESUMO
In order to investigate the effects of early protein malnutrition and environmental stimulation upon the response to the anxiolytic properties of diazepam, two animal models of anxiety (elevated plus-maze and light-dark transition tests) were used. Rats were malnourished by feeding their dams a 6% protein diet during the lactation period (0-21 days of age) while well-nourished controls received a 16% protein diet. From 21 to 70 days of age all rats received a balanced lab chow diet. Environmental stimulation consisted of 3-min daily handling from birth to 70 days of age. Additional stimulation was provided from 21 to 70 days of age by rearing the rats in an enriched living cage. Eight groups of rats were studied in a 2 (malnourished or well-nourished) x 2 (stimulated or nonstimulated) x 2 (diazepam or vehicle) design. At 70 days of age, independent groups of rats treated with diazepam (2.5 mg/kg, IP) or vehicle were submitted to testing in the elevated plus-maze or light-dark transition procedures. The results showed that both diazepam and environmental stimulation reduced anxiety in the elevated plus-maze; stimulation changed the anxiolytic response to diazepam and the two diet conditions altered differentially the response to both pharmacological and stimulation procedures. These results suggest that environmental stimulation can affect differentially the behavioral response of malnourished and well-nourished rats treated with diazepam.
Assuntos
Ansiedade/psicologia , Diazepam/farmacologia , Meio Ambiente , Desnutrição Proteico-Calórica/psicologia , Animais , Comportamento Animal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Escuridão , Dieta , Manobra Psicológica , Masculino , Ratos , Ratos WistarRESUMO
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% 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 (21st 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 acquisition of the avoidance response, but malnourished groups required more trials to extinguish jumping and two-way shuttle-box. During the acquisition 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 extinction 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 parameters for detecting differences between well-nourished and malnourished animals.
Assuntos
Aprendizagem da Esquiva/fisiologia , Desnutrição Proteico-Calórica/fisiopatologia , Animais , Peso Corporal , Estimulação Elétrica , Masculino , Ratos , Ratos WistarRESUMO
PURPOSE: To study the spatial arrangement of the bundles of myocardial fibers presents in the left atrial-venous junctions and in the wall of the pulmonary veins. METHODS: The study was made on 24 human adult hearts, together with pulmonary vessels, fixed in 10% formaldehyde solution. Each specimen was cleared of remnants of pericardium to expose the myocardial fibers as clearly as possible. Particular attention was paid to the atrial-venous junction and the extension of the myocardial fibers in the pulmonary veins. The specimens were embedded in celloidin and cut serially at a thickness of 70 mu and stained by methods of Azan's trichrome. RESULTS: The myocardial bundles leave the atrial wall around the openings of all pulmonary veins forming a sphincter-like structure. These fibers are continuous in the adventitial coat running in oblique or spiral directions. Some bundles, more external, leaving from the atrial wall, surround the ostium of the veins and return to the atrium, forming true loops. CONCLUSION: The extremities of the pulmonary veins and their junctions with the atrium have a morphological substract which may be of physiological importance in the control of the pulmonary venous pressure and blood flow.
Assuntos
Átrios do Coração/anatomia & histologia , Veias Pulmonares/anatomia & histologia , Adulto , Função Atrial , Feminino , Humanos , Masculino , Veias Pulmonares/fisiologiaRESUMO
An elevated plus-maze was used to investigate the effects of repeated testing on the locomotor and exploratory behaviors of malnourished rats. Pup malnutrition was induced during the lactation period (0 to 21 days of age) by feeding the dams a protein-deficient diet (6% protein) and the animals were allowed to recover from weaning to 70 days of age by eating a commercial lab chow diet. Control animals were suckled by dams receiving a normal protein diet (16% protein) during the lactation period and were fed a commercial lab chow diet after weaning. At 70 days, malnourished and control animals were placed on the central platform of the elevated plus-maze facing an enclosed arm and allowed to explore for 5 min. This procedure was repeated at 24-h intervals for 6 days. The repeated testing in the elevated plus-maze did not change the total number of arm entries and attempts to enter open arms, but decreased the percentage of open arm entries, time spent in open arms, and total time spent on the central platform. These data suggest an increase in anxiety with repeated testing in the elevated plus-maze. In addition, the malnourished animals showed a larger number of both rearings and attempts to enter the open arms, suggesting a high level of exploration and/or high impulsiveness of these animals as compared to control. The elevated plus-maze proved to be a useful animal model to evaluate exploratory behaviors in early protein malnourished animals.
Assuntos
Ansiedade/psicologia , Comportamento Exploratório/fisiologia , Atividade Motora/fisiologia , Desnutrição Proteico-Calórica/psicologia , Animais , Peso Corporal/fisiologia , Masculino , Ratos , Ratos WistarRESUMO
Microinjection of L-glutamic acid into the basal midbrain of the toad Bufo paracnemis induced a series of responses linked to antipredator behavior such as flight, backward locomotion and defensive postures. Furthermore, alerting/orientation occurred in 20% of the animals, a behavior which is probably important for the animal to achieve the above responses. Locomotion occurred in 18% of the toads. The existence of a mesencephalic premotor control for locomotion in these animals is discussed comparatively. All responses were accompanied by changes in arterial pressure, heart rate and intrabuccal pressure. In some animals which exhibited backward locomotion responses, defensive postures and alerting/orientation, bradycardia or cardiac arrest occurred, with no appreciable changes in arterial pressure. This fact is discussed on the basis of studies which have shown the occurrence of similar alterations in situations of fear in other vertebrates. Autonomic changes without other responses occurred in 16% of the animals. Flight behavior was usually observed as a consequence of stimulation of sites located in the anterodorsal tegmental nucleus and lateral portions of the midbrain tegmentum. In contrast, locomotion was obtained by stimulating basal sites of the tegmentum located in the anteroventral nucleus and in the reticular formation lateral to it. Sites related to the remaining behaviors were located more diffusely in the basal midbrain.