Active learning methodology, associated to formative assessment, improved cardiac physiology knowledge and decreased pre-test stress and anxiety.

Stress and anxiety caused by assessments are often related to the student's insecurity regarding the knowledge to be evaluated, while teaching strategies that increase effective learning can assist in reducing it. The aim of this study was to evaluate the hypothesis that the use of an active methodology, associated to formative assessment, could reduce students' anxiety and stress, when compared to the traditional method, by promoting greater learning. New students enrolled in the same discipline of a Dentistry course were invited to participate in the study and were divided into two groups: traditional method and active methodology. The traditional method group received two lectures, delivered orally. The active methodology group received a lecture about cardiac cells and the autonomic control of cardiac function, with home study of the cardiac cycle using a textbook. In the second class, an individual formative assessment was applied. Afterwards, a group activity was performed with an educational game about the cardiac cycle, followed by a group formative assessment. After applying the traditional or active methodology, test 1 was carried out. Immediately before this test, saliva samples were collected for determination of the concentrations of the stress biomarkers cortisol and α-amylase. The students also answered the State-Trait Anxiety Inventory questionnaire, used for anxiety level determination. The score obtained in the test 1 was significantly higher for the active methodology group, compared to the traditional method group. No significant differences between the groups were observed for baseline cortisol and salivary α-amylase concentrations, or for anxiety scores. Before test 1, traditional method group presented higher concentrations of salivary cortisol and α-amylase, compared to the respective baseline values, while the active methodology group showed no difference between the baseline and test 1 levels. Before test 1, there were increases in anxiety levels, relative to the respective baseline values, regardless of the teaching methodology used, but this increase was greater for the traditional method group, compared to the active methodology group. These results showed that the active methodology, associated to formative assessment, decreased test stress and anxiety, with improved student performance in comparison to traditional lectures.

An educational game for teaching osmolarity and tonicity: opinions of dental and medical students.

In health courses, the students must be familiar with the effects of intravenous solutions on cell volume and function, a topic where there can be learning difficulties and misunderstandings. Since educational games can assist in understanding complex concepts, we created a game relating solution osmolarity and tonicity to red blood cell volume that was used in undergraduate Dentistry and Medicine courses. The students, working in groups, completed the game board by indicating the effect of the solutions on the red blood cell volume and classifying the solutions in terms of tonicity and osmolarity. The student indicated that the use of the educational game contributed to their understanding of osmolarity and tonicity.NEW & NOTEWORTHY This study describes an educational game for teaching osmolarity and tonicity, using classical red blood cell experiment results. The game was used during dialogic teaching, which was interrupted three times so that the student groups could answer questions about the experiments by completing a table describing the effects of different solutions on cell volume. According to the students' perception, the game contributed to their understanding of osmolarity and tonicity as related to human cells.

Percepções e práticas parentais associadas ao consumo alimentar e estado nutricional em crianças pré-escolares / Perceptions and parenting practices associated with food consumption and nutritional status in preschool children

Understanding infant diet is of great importance to elucidate its determining factors. It is known that parents exert great influence on the formation of their children's eating behavior and are able to define their children's eating patterns at other moments in their future life cycles. However, the effects of parental practices and perceptions on the food consumption and nutritional status of their children need to be elucidated more clearly. This study aimed to verify the association of parental practices and perceptions with food consumption and nutritional status of children. This is a cross-sectional study, conducted with parents and children aged two to six years old. Questionnaires were applied using the Google Forms® platform to investigate parental practices and perceptions, sociodemographic data, weight and height, child food consumption, and family food routine. The instruments used in data collection were the Child Feeding Questionnaire, the Child Feeding Frequency Questionnaire, and the authors' own questions. For statistical analysis, p<0.05 was considered significant. Sixty-eight parents of children were interviewed, of which 89.7% were mothers and 72.1% worked outside the home. Among children, 54.4% were male and 60.3% eutrophic. Among those parents who worked outside the home, preschoolers had most of their meals at school. There was an association between the parents' perception of the child's weight and nutritional status, frequency of parental responsibility in deciding the right type of food with the child's nutritional status, and parents' education. Controlling the intake of sweets was associated with parental age. Snack consumption by children was associated with parental education. It was concluded that parental practices and perceptions were associated with the nutritional status of preschoolers, but there was no association with food consumption.

Entender a alimentação infantil é de grande importância para elucidar os seus determinantes. Sabe-se que os pais exercem grande influência sobre a formação do comportamento alimentar da criança, podendo definir os padrões alimentares de seus filhos em outros momentos de seus ciclos de vida futuro. Entretanto, os efeitos das práticas e percepções parentais sobre o consumo alimentar e estado nutricional de seus filhos precisam ser elucidados com mais clareza. Este estudo teve como objetivo verificar a associação das práticas e percepções parentais com o consumo alimentar e estado nutricional de crianças. Trata-se de um estudo transversal, conduzido com pais e crianças de dois a seis anos. Aplicou-se questionários pela plataforma Google Forms®, para investigar as práticas e percepções parentais, dados sociodemográficos, peso e estatura, consumo alimentar infantil e rotina alimentar da família. Os instrumentos utilizados na coleta de dados foram o Questionário de Alimentação da Criança, Questionário de Frequência Alimentar da Criança e questões de autoria própria. Para análise estatística considerou-se significativo p<0,05. Foram entrevistados 68 pais de crianças, sendo que 89,7% eram mães e 72,1% trabalhavam fora de casa. Entre as crianças, 54,4% eram do sexo masculino e 60,3% eutróficos. Dentre aqueles pais que trabalhavam fora de casa, os pré-escolares realizavam a maior parte das refeições na escola. Verificou-se associação entre a percepção dos pais sobre o peso da criança e estado nutricional; frequência da responsabilidade dos pais em decidir o tipo correto de comida com o estado nutricional infantil e com a escolaridade dos pais. O controle da ingestão de doces associou-se à idade dos pais. O consumo de lanches pelas crianças associou-se a escolaridade dos pais. Concluiu-se que as práticas e percepções parentais foram associadas ao estado nutricional de pré-escolares, porém não houve associação com o consumo alimentar.

Stress-induced cardiometabolic perturbations, increased oxidative stress and ACE/ACE2 imbalance are improved by endurance training in rats.

AIMS: To investigate the effects of endurance training on stress-induced cardiometabolic perturbations given the elevated release of stress hormones and subsequent glucose homeostasis perturbations. MATERIALS AND METHODS: Rats were randomized into non-trained rats, rats submitted to endurance training, non-trained rats submitted to stress, and trained rats submitted to stress. Endurance training was applied for 8 weeks, while chronic stress was applied at the 4th, 5th, and 6th weeks of the training period. Two weeks after the last stressor stimuli, rats were euthanized, and blood and heart were collected for biochemical tests. KEY FINDINGS: Exacerbated corticosterone levels were observed in both stressed groups, and chronic stress per se impaired glucose tolerance and insulin sensitivity. Training reduced circulating adrenaline, even though noradrenaline levels were elevated in the blood and heart of trained rats. While stress-induced high circulating serotonin levels were further increased by endurance training, cardiac serotonin levels were attenuated in trained rats. Endurance training mitigated the stress-induced higher circulating lipids. Cardiac TBARs and GPx activity increased in trained rats while CAT and GPx were reduced in response to chronic stress. Endurance training not only attenuated the stress-induced higher circulating ACE/ACE2 ratio but also reduced ACE/ACE2 balance in the heart. Glucose intolerance, insulin resistance, and altered stress hormones release were linked to impairment of cardiometabolic responses, elevated oxidative stress, and dysregulation of ACE/ACE2 ratio. SIGNIFICANCE: Endurance training mitigated the stress-related pathophysiological responses, which could be related to improvements in the antioxidant capacity and the balance of ACE/ACE2 activity.

Percepções e práticas parentais associadas ao consumo alimentar e estado nutricional em crianças pré-escolares / Perceptions and parenting practices associated with food consumption and nutritional status in preschool children

Entender a alimentação infantil é de grande importância para elucidar os seus determinantes. Sabe-se que os pais exercem grande influência sobre a formação do comportamento alimentar da criança, podendo definir os padrões alimentares de seus filhos em outros momentos de seus ciclos de vida futuro. Entretanto, os efeitos das práticas e percepções parentais sobre o consumo alimentar e estado nutricional de seus filhos precisam ser elucidados com mais clareza. Este estudo teve como objetivo verificar a associação das práticas e percepções parentais com o consumo alimentar e estado nutricional de crianças. Trata-se de um estudo transversal, conduzido com pais e crianças de dois a seis anos. Aplicou-se questionários pela plataforma Google Forms®, para investigar as práticas e percepções parentais, dados sociodemográficos, peso e estatura, consumo alimentar infantil e rotina alimentar da família. Os instrumentos utilizados na coleta de dados foram o Questionário de Alimentação da Criança, Questionário de Frequência Alimentar da Criança e questões de autoria própria. Para análise estatística considerou-se significativo p<0,05. Foram entrevistados 68 pais de crianças, sendo que 89,7% eram mães e 72,1% trabalhavam fora de casa. Entre as crianças, 54,4% eram do sexo masculino e 60,3% eutróficos. Dentre aqueles pais que trabalhavam fora de casa, os pré-escolares realizavam a maior parte das refeições na escola. Verificou-se associação entre a percepção dos pais sobre o peso da criança e estado nutricional; frequência da responsabilidade dos pais em decidir o tipo correto de comida com o estado nutricional infantil e com a escolaridade dos pais. O controle da ingestão de doces associou-se à idade dos pais. O consumo de lanches pelas crianças associou-se a escolaridade dos pais. Concluiu-se que as práticas e percepções parentais foram associadas ao estado nutricional de pré-escolares, porém não houve associação com o consumo alimentar.

Understanding infant diet is of great importance to elucidate its determining factors. It is known that parents exert great influence on the formation of their children's eating behavior and are able to define their children's eating patterns at other moments in their future life cycles. However, the effects of parental practices and perceptions on the food consumption and nutritional status of their children need to be elucidated more clearly. This study aimed to verify the association of parental practices and perceptions with food consumption and nutritional status of children. This is a cross-sectional study, conducted with parents and children aged two to six years old. Questionnaires were applied using the Google Forms® platform to investigate parental practices and perceptions, sociodemographic data, weight and height, child food consumption, and family food routine. The instruments used in data collection were the Child Feeding Questionnaire, the Child Feeding Frequency Questionnaire, and the authors' own questions. For statistical analysis, p<0.05 was considered significant. Sixty-eight parents of children were interviewed, of which 89.7% were mothers and 72.1% worked outside the home. Among children, 54.4% were male and 60.3% eutrophic. Among those parents who worked outside the home, preschoolers had most of their meals at school. There was an association between the parents' perception of the child's weight and nutritional status, frequency of parental responsibility in deciding the right type of food with the child's nutritional status, and parents' education. Controlling the intake of sweets was associated with parental age. Snack consumption by children was associated with parental education. It was concluded that parental practices and perceptions were associated with the nutritional status of preschoolers, but there was no association with food consumption.

Nandrolone combined with strenuous resistance training impairs myocardial proteome profile of rats.

We aimed to investigate the effects of high doses of nandrolone decanoate and resistance training (RT) on the proteomic profile of the left ventricle (LV) of rats, using a label-free quantitative approach. Male rats were randomized into four groups: untrained vehicle (UTV), trained vehicle (TV), untrained nandrolone (UTN), and trained nandrolone (TN). Rats were familiarized with the exercise training protocol (jump exercise) for one week. Jump-exercise was performed five days a week for 6 weeks, with 30 s of inter-set rest intervals. Nandrolone was administrated for 6 weeks (5 mg/kg, twice a week, via intramuscular). Systolic and diastolic arterial pressure and heart rate were measured 48 h post-training. LV was isolated and collagen content was measured. The expression of cardiac proteins was analyzed by ultra-efficiency liquid chromatography with mass spectrometry high / low collision energy (UPLC/MSE). Nandrolone and RT led to cardiac hypertrophy, even though high doses of nandrolone counteracted the RT-induced arterial pressures lowering. Nandrolone also affected the proteome profile negatively in LV of rats, including critical proteins related to biological processes (metabolism, oxidative stress, inflammation), structural function and membrane transporters. Our findings show physiological relevance since high doses of nandrolone induced detrimental effects on the proteome profile of heart tissue and hemodynamic parameters of rats. Furthermore, as nandrolone abuse has become increasingly common among recreational athletes and casual fitness enthusiasts, we consider that our findings have clinical relevance as well.

Educação sexual entre adolescentes: um estudo de caso / Sexual education between adolescents: a case study / Educación sexual entre adolescentes: un estudio de caso

Objetivo: identificar a expectativa dos adolescentes sobre educação sexual; caracterizar o perfil socioeconômico e cultural dos adolescentes de uma escola da rede privada do município de São Gonçalo/RJ. Metodologia: trata-se de estudo descritivo, exploratório de natureza qualitativa, estudo de caso com coleta de dados, realizada entrevista individual a fim de obter dados socioeconômicos e culturais dos entrevistados; técnica de grupo focal que utilizou roteiro orientado por algumas perguntas norteadoras para apreensão das concepções sobre as expectativas da educação sexual. O estudo foi aprovado pelo Comitê de Ética do Hospital Universitário Antônio Pedro, sob o CAAE: 0265.0.258.000-10. Resultados: emergiram duas categorias: Papo sério: conversando com adolescentes sobre educação sexual no âmbito escolar e sociedade reafirmando tabus na questão da sexualidade. Conclusão: os adolescentes entendem que a escola e a família devem trabalhar em conjunto desempenhando papel importante na educação para sexualidade ligada à vida, à saúde, ao prazer e ao bem-estar.(AU)

Objective: to identify adolescents' expectations about sex education; characterize the socioeconomic and cultural profile of adolescents from a private school in the city of São Gonçalo / RJ. Methodology: this is a descriptive, exploratory study of a qualitative nature, a case study with data collection, an individual interview was conducted in order to obtain socioeconomic and cultural data from the interviewees; focus group technique that used a script guided by some guiding questions to apprehend the conceptions about the expectations of sex education. The study was approved by the Ethics Committee of Hospital Universitário Antônio Pedro, under CAAE: 0265.0.258.000-10. Results: two categories emerged: Serious conversation: talking to teenagers about sex education in the school and society reaffirming taboos on the issue of sexuality. Conclusion: the adolescents understand that the school and the family must work together playing an important role in education for sexuality linked to life, health, pleasure and well-being.(AU)

Objetivo: identificar las expectativas de los adolescentes sobre la educación sexual; caracterizar el perfil socioeconómico y cultural de los adolescentes de una escuela privada en la ciudad de São Gonçalo / RJ. Metodología: este es un estudio descriptivo, exploratorio de naturaleza cualitativa, un estudio de caso con recolección de datos, se realizó una entrevista individual para obtener datos socioeconómicos y culturales de los entrevistados; técnica de grupo focal que utilizaba un guión guiado por algunas preguntas orientadoras para comprender las concepciones sobre las expectativas de la educación sexual. El estudio fue aprobado por el Comité de Ética del Hospital Universitario Antônio Pedro, bajo el CAAE: 0265.0.258.000-10. Resultados: surgieron dos categorías: conversación seria: hablar con los adolescentes sobre la educación sexual en la escuela y la sociedad, reafirmando tabúes sobre el tema de la sexualidad. Conclusión: los adolescentes entienden que la escuela y la familia deben trabajar juntas, desempeñando un papel importante en la educación para la sexualidad vinculada a la vida, la salud, el placer y el bienestar.(AU)

Modulatory action of environmental enrichment on hormonal and behavioral responses induced by chronic stress in rats: Hypothalamic renin-angiotensin system components.

Environmental enrichment (EE) has been studied as a protocol that can improve brain plasticity and may protect against negative insults such as chronic stress. The aim of this study was to evaluate the effects of EE on the hormonal and behavioral responses induced by chronic mild unpredictable stress (CMS) in rats, considering the involvement of the renin-angiotensin system. Male adult rats were divided into 4 groups: control, CMS, EE, and CMS + EE, and the experimental protocol lasted for 7 weeks. EE was performed during 7 weeks, 5 days per week, 2 h per day. CMS was applied during weeks 3, 4, and 5. After the CMS (week 6), depression-like behavior was evaluated by forced swimming and sucrose consumption tests, anxiety level was evaluated using the elevated plus-maze test, and memory was evaluated using the Y-maze test. On week 7, the animals were euthanized and basal plasma levels of corticosterone and catecholamines were determined. The hypothalamus was isolated and tissue levels of angiotensin peptides were evaluated. CMS increased plasma corticosterone, norepinephrine, and epinephrine basal concentrations, induced depression-like behaviors, impaired memory, and increased hypothalamic angiotensin I, II, and IV concentrations. EE decreased stress hormones secretion, depression-like behaviors, memory impairment, and hypothalamic angiotensin II induced by stress. Reductions of anxiety-like behavior and norepinephrine secretion were observed in both stressed and unstressed groups. The results indicated that EE seemed to protect adult rats against hormonal and behavioral CMS effects, and that the reduction of angiotensin II could contribute to these effects.

Recreational training improves cardiovascular adaptations, metabolic profile and mental health of elderly women with type-2 diabetes mellitus.

We investigated the effects of a recreational training (RET) protocol in elderly women with type-2 diabetes mellitus (T2DM). We hypothesized that non-conventional physical activities of RET protocol might improve clinical outcomes regarding cardiovascular function, metabolic profile and mental health as participants keep the adherence to the protocol during the 3-month follow-up. Cardiovascular parameters (heart rate, systolic and diastolic blood pressure), circulating biomarkers (glucose and lipids) and salivary cortisol were attenuated in response to exercise. RET also reduced anxiety and depression indexes. RET protocol constitutes a potential therapeutic approach for managing T2DM in elderly women.

Effect of an active learning methodology combined with formative assessments on performance, test anxiety, and stress of university students.

The aim of this study was to evaluate the effect of an active methodology combined with a lecture on undergraduate student learning and levels of stress and anxiety. The active learning methodology consisted of a lecture of 50-min duration, study at home with a textbook, an educational game activity, and three formative assessments on the topic of the cardiac cycle. In a following class, the students provided saliva samples to evaluate their levels of stress, received an anxiety test, and then undertook an exam to assess their understanding of the cardiac cycle. The traditional teaching methodology consisted of two lectures (∼2-h duration) on blood pressure control systems, delivered orally. In the third class, the students provided saliva samples, received an anxiety test, and then undertook an exam to assess their understanding of blood pressure control systems. The level of stress was assessed with the concentrations of the stress biomarkers cortisol and alpha-amylase in saliva. Anxiety was assessed with the State-Trait Anxiety Inventory (STAI) questionnaire. The students achieved significantly higher average scores in exams when the active learning strategy was applied compared with the use of traditional theoretical classes. The active methodology resulted in significantly lower levels of stress and anxiety, as well as improved student performance, compared with the use of traditional lectures.

Effects of academic stress on the levels of oral volatile sulfur compounds, halitosis-related bacteria and stress biomarkers of healthy female undergraduate students.

To investigate whether academic stress changes the salivary microbiota and its relationship with salivary parameters, evaluating the effects on the production of volatile sulfur compounds (VSCs) in healthy women. Fifty-five women who were enrolled in a four-year Dentistry course were assessed for academic stress by the questionnaire Maslach Burnout Inventory-Student Survey and were then classified into 'Not Stressed' and 'Stressed' groups. Cortisol and alpha-amylase (AA) were measured as physiological stress biomarkers. Oral Chroma™ gas chromatograph was used to measure concentrations of hydrogen sulfide (H2S), methyl mercaptan and dimethyl sulfide. Salivary proteins were evaluated by western blot. Quantitative polymerase chain reaction was used to identify the salivary amounts of halitosis-associated bacteria. The 'Stressed' volunteers showed higher levels of H2S, AA, Fusobacterium nucleatum and total bacteria, compared to the 'Not Stressed' individuals (p < 0.05; Mann-Whitney test). Salivary proteins showed no differences between groups (p > 0.05; Mann-Whitney test). Academic stress was positively correlated with H2S, total bacteria and F. nucleatum counts, while F. nucleatum was positively correlated with AA. H2S showed positive correlations with AA and Solobacterium moorei (p < 0.05; Spearman correlation). Beta-defensin (BD) presented negative correlations with H2S and S. moorei (p < 0.05; Spearman correlation). Academic stress increased salivary F. nucleatum and total bacteria, as well as AA activity. The protein BD showed important correlations with bacteria and VSC. These changes appeared to be accountable for increased H2S production in the stressed women.

Integrating synapse, muscle contraction, and autonomic nervous system game: effect on learning and evaluation of students' opinions.

This work describes the educational game "Integrating Synapse, Muscle Contraction, and Autonomic Nervous System," which was developed to assist students in understanding and integrating concepts related to the physiology of synapses, muscle contraction, and the autonomic nervous system. Analysis was made of the effect of the game on learning and the students' opinions about it. Dentistry students were divided into control and game groups. They attended lectures about the topics, after which the control group students were submitted to a test, whereas the game group performed the game activity before undertaking the test. The mean score was significantly higher for the game group, compared with the control group (P < 0.05). Pharmacy students also attended lectures about these topics; in the next class, the students performed a pretest and the activity with the educational game. After the game, a posttest was applied. The mean scores were significantly higher for the posttest than for the pretest (P < 0.05). Students of medicine attended the lectures and performed the activity with the educational game, without the learning assessment. All of the students answered a question, using a 5-point Likert-type scale, concerning whether they thought the activity with the game was useful for learning. The mean scores obtained by the dentistry, pharmacy, and medicine students were 4.7 ± 0.6, 4.9 ± 0.3, and 4.3 ± 0.1, respectively. The educational game increased the learning of the undergraduate students, in agreement with their opinions of the strategy.

Tactile stimulation of adult rats modulates hormonal responses, depression-like behaviors, and memory impairment induced by chronic mild stress: Role of angiotensin II.

Physical touch can help to decrease the effects of stress. The aim of this study was to evaluate the influence of tactile stimulation on the hormonal and behavioral responses of young adult rats submitted to chronic mild unpredictable stress (CMS), considering the role of angiotensin II (Ang II). In Experiment 1, male rats were divided into 4 groups: control, stress, tactile stimulation (TS), and stress + TS. CMS was applied for three weeks. Tactile stimulation was applied for seven weeks, five days a week. After the CMS protocol, depression-like behaviors were evaluated by forced swimming and sucrose consumption tests. Learning and memory were evaluated using the Y-maze test. Fifteen days after the CMS procedure, the animals were euthanized and the levels of stress hormones were determined. The hypothalamus was isolated for determination of the Ang II concentration. In Experiment 2, control and stressed rats, with or without treatment using losartan (angiotensin II type 1 receptor blocker), were evaluated using the same behavioral tests and the hypothalamus Ang II concentration was also determined. CMS increased plasma corticosterone, norepinephrine, and epinephrine concentrations, induced depression-like behaviors, impaired learning and memory, and increased the Ang II concentration in the hypothalamus. Tactile stimulation attenuated these stress-induced effects. Losartan treatment effectively prevented increase of the hypothalamic Ang II concentration and the development of depression-like behavior, and also reduced the impairment of learning and memory in the stressed animals. The results indicated that tactile stimulation seemed to protect adult rats against hormonal and behavioral chronic stress effects, and that Ang II could be involved in the CMS effects.

Increased learning by using board game on muscular system physiology compared with guided study.

The aim of this work is to describe the "Muscular System Game," created to assist in the teaching-learning process concerning the physiology of the muscular system, and to evaluate its effect on the learning of university students. Participating in this study were first-year undergraduate students of the pharmacy course (game group, n = 21, 5 men and 16 women, age 23.57 ± 4.92 yr) and the nursing course (control group, n = 22, 2 men and 20 women, age 22.90 ± 4.93 yr), who had the same level of preparation. After theoretical classes concerning the physiology of the muscular system, all students were instructed to study the topic. In the next week, the students of the game group performed the activity with the board game, and the students of the control group undertook a guided study activity, which contained a list of exercises with the same questions used in the game, to be answered by groups. In the week following these activities, all of the students answered evaluation questions about the topic. The scores obtained for the two groups in the evaluation were compared using Student's t-test for unpaired samples, considering a significance level of 0.05. The score obtained for the control group (5.78 ± 0.38) was significantly lower than the score for the game group (7.50 ± 0.47; P < 0.05). The results obtained indicating that the use of an educational board game about the physiology of muscle contraction resulted in significantly improved learning, compared with the use of guided study.

Intense resistance training induces pronounced metabolic stress and impairs hypertrophic response in hind-limb muscles of rats.

Skeletal muscle hypertrophy is an exercise-induced adaptation, particularly in resistance training (RT) programs that use large volumes and low loads. However, evidence regarding the role of rest intervals on metabolic stress and muscular adaptations is inconclusive. Thus, we aimed to investigate the effects of a strenuous RT model (jump-training) on skeletal muscle adaptations and metabolic stress, considering the scarce information about RT models for rats. We hypothesized that jump-training induces metabolic stress and influences negatively the growth of soleus (SOL) and extensor digitorum longus (EDL) muscles of rats. Male Wistar rats (aged 60 days) were randomly assigned to non-trained or trained groups (n = 8/group). Trained rats performed jump-training during 5 days a week for 1, 3, or 5 weeks with 30 s of inter-set rest intervals. Forty-eight hours after the experimental period, rats were euthanized and blood samples immediately drawn to measure creatine kinase activity, lactate and corticosterone concentrations. Muscle weight-to-body weight ratio (MW/BW), cross-sectional area (CSA) and myosin heavy chain (MHC) isoform expression were determined. Higher lactate levels occurred after 20 min of training in weeks 1 and 3. Corticosterone levels were higher after 5 weeks of training. Jump-training had negative effects on hypertrophy of types-I and II muscle fibers after 5 weeks of training, as evidenced by decreased CSA and reduced muscle weight. Our results demonstrated that pronounced metabolic stress and impairment of muscle growth might take place when variables of exercise training are not appropriately manipulated. Lay summary Resistance training (RT) has been used to increase muscle mass. In this regard, training variables (intensity, volume, and frequency) must be strictly controlled in order to evoke substantial muscular fitness. This study shows that rats submitted to 5 weeks of intensive resistance jump-training - high intensity, large volume, and short rest intervals - present high levels of blood corticosterone associated with negative effects on hypertrophy of types-I and II muscle fibers.

Stress-related salivary proteins affect the production of volatile sulfur compounds by oral bacteria.

OBJECTIVE: To determine whether stress-related substances and sex hormones influence the growth and in vitro production of volatile sulfur compounds (VSCs) by Solobacterium moorei and Fusobacterium nucleatum. MATERIALS AND METHODS: Bacteria growth and VSCs production were evaluated in the presence of alpha-amylase, beta-defensin-2, mucin, estradiol, and progesterone. Growth was evaluated by colony counting, and the production of the VSCs hydrogen sulfide (H2 S) and methyl mercaptan (CH3 SH) was measured using the Oral Chroma™ instrument. RESULTS: Mucin induced the production of H2 S by both bacteria, but had a slight inhibitory effect on CH3 SH production by F. nucleatum. It also increased the viability of F. nucleatum. Alpha-amylase increased H2 S production by S. moorei and CH3 SH production by F. nucleatum, but had no effect on H2 S production by F. nucleatum. No substance altered the viability of S. moorei. No effects of beta-defensin-2, estradiol, or progesterone were observed. CONCLUSION: The salivary stress-related proteins mucin and alpha-amylase altered VSCs production by F. nucleatum and S. moorei, favoring H2 S production. These findings are a step toward understanding the relation between stress and increased amounts of H2 S.

Blockade of AT1 type receptors for angiotensin II prevents cardiac microvascular fibrosis induced by chronic stress in Sprague-Dawley rats.

To test the effects of chronic-stress on the cardiovascular system, the model of chronic mild unpredictable stress (CMS) has been widely used. The CMS protocol consists of the random, intermittent, and unpredictable exposure of laboratory animals to a variety of stressors, during 3 consecutive weeks. In this study, we tested the hypothesis that exposure to the CMS protocol leads to left ventricle microcirculatory remodeling that can be attenuated by angiotensin II receptor blockade. Male Sprague-Dawley rats were randomly assigned into four groups: Control, Stress, Control + losartan, and Stress + losartan (N = 6, each group, losartan: 20 mg/kg/day). The rats were euthanized 15 days after CMS exposure, and blood samples and left ventricle were collected. Rats submitted to CMS presented increased glycemia, corticosterone, noradrenaline and adrenaline concentration, and losartan reduced the concentration of the circulating amines. Cardiac angiotensin II, measured by high-performance liquid chromatography (HPLC), was significantly increased in the CMS group, and losartan treatment reduced it, while angiotensin 1-7 was significantly higher in the CMS losartan-treated group as compared with CMS. Histological analysis, verified by transmission electron microscopy, showed that rats exposed to CMS presented increased perivascular collagen and losartan effectively prevented the development of this process. Hence, CMS induced a state of microvascular disease, with increased perivascular collagen deposition, that may be the trigger for further development of cardiovascular disease. In this case, CMS fibrosis is associated with increased production of catecholamines and with a disruption of renin-angiotensin system balance, which can be prevented by angiotensin II receptor blockade.