Aging is a complex biological process, with gradual and progressive decline in structure and func... more Aging is a complex biological process, with gradual and progressive decline in structure and function in many organ systems. Our objective is to determine if structural changes produced by aging, vary with sex, in a stressful situation such as dehydration. The expression of Slc12a3 mRNA in renal cortex, α-smooth muscle actin (α-SMA) and fibronectin, was evaluated in male and female rats aged 3 and 18 months submitted or not to water deprivation (WD) for 48 hours. When comparing ages, 18-month-old males showed lower expression of Slc12a3 mRNA than 3-month-old males, and control and WD 18-moth-old male and female rats exhibited higher expression of α-SMA than respective 3-month-old rats. Fibronectin was higher in both control and WD 18-month-old males than respective 3-month-old males. In females, only control 18-month-old rats showed higher fibronectin than control 3-month-old rats. When we compared sex, control and WD 3-month-old female rats had lower expression of Slc12a3 mRNA than...
ABSTRACT
Introduction: The concept of “learning styles” derives from theories postulating that s... more ABSTRACT
Introduction: The concept of “learning styles” derives from theories postulating that students learn by following diverse pathways and that
learning is more effective when the adopted teaching strategies more closely match specific student characteristics and learning preferences.
Objectives: To determine, in first-year students attending different undergraduate courses in the health area at the same higher education
institution, the frequency of different learning styles, categorized according to the four dimensions of Felder & Soloman (FS) model, and to detect
any differences associated with the type of course and gender.
Method: The study population (N=283; 190 women) consisted of first-year students attending the Medicine, Biomedical Sciences, Physical Therapy,
Speech-Language Pathology, Nutrition and Metabolism, and Occupational Therapy courses, with 68.2% of them aged between 18 and 20 years.
The students answered a sociodemographic characterization questionnaire and the FS Index of Learning Styles (ILS) questionnaire, which allowed
determining the frequencies of the different learning styles and their associations with the type of undergraduate course and gender.
Results: the student group showed a predominance of “Sensory”, “Visual”, “Reflective” and “Sequential”, learning styles, in the “Perception”, “Input”,
“Processing” and “Understanding” dimensions of learning, respectively. There was no statistically significant difference in terms of learning styles,
in any of the dimensions, that could be associated with the type of course and gender, although women showed a significant predominance of
the “Reflective” style in the “Processing” dimension.
Conclusion: It was not possible to establish significant differences between the different undergraduate courses in the health area, or between
men and women, regarding the students’ predominant learning styles, although women showed a significantly higher frequency of the Reflective
style. These findings must be considered when planning learning activities and, mainly, in pedagogical support, giving students the opportunity
to learn about their learning styles and helping them to better adapt to the strategies employed in each institution.
Introduction: The concept of "learning styles" derives from theories postulating that students le... more Introduction: The concept of "learning styles" derives from theories postulating that students learn by following diverse pathways and that learning is more effective when the adopted teaching strategies more closely match specific student characteristics and learning preferences. Objectives: To determine, in first-year students attending different undergraduate courses in the health area at the same higher education institution, the frequency of different learning styles, categorized according to the four dimensions of Felder & Soloman (FS) model, and to detect any differences associated with the type of course and gender. Method: The study population (N=283; 190 women) consisted of first-year students attending the Medicine, Biomedical Sciences, Physical Therapy, Speech-Language Pathology, Nutrition and Metabolism, and Occupational Therapy courses, with 68.2% of them aged between 18 and 20 years. The students answered a sociodemographic characterization questionnaire and the FS Index of Learning Styles (ILS) questionnaire, which allowed determining the frequencies of the different learning styles and their associations with the type of undergraduate course and gender. Results: the student group showed a predominance of "Sensory", "Visual", "Reflective" and "Sequential", learning styles, in the "Perception", "Input", "Processing" and "Understanding" dimensions of learning, respectively. There was no statistically significant difference in terms of learning styles, in any of the dimensions, that could be associated with the type of course and gender, although women showed a significant predominance of the "Reflective" style in the "Processing" dimension. Conclusion: It was not possible to establish significant differences between the different undergraduate courses in the health area, or between men and women, regarding the students' predominant learning styles, although women showed a significantly higher frequency of the Reflective style. These findings must be considered when planning learning activities and, mainly, in pedagogical support, giving students the opportunity to learn about their learning styles and helping them to better adapt to the strategies employed in each institution.
Aging is a complex biological process, with gradual and progressive decline in structure and func... more Aging is a complex biological process, with gradual and progressive decline in structure and function in many organ systems. Our objective is to determine if structural changes produced by aging, vary with sex, in a stressful situation such as dehydration. The expression of Slc12a3 mRNA in renal cortex, α-smooth muscle actin (α-SMA) and fibronectin, was evaluated in male and female rats aged 3 and 18 months submitted or not to water deprivation (WD) for 48 hours. When comparing ages, 18-month-old males showed lower expression of Slc12a3 mRNA than 3-month-old males, and control and WD 18-moth-old male and female rats exhibited higher expression of α-SMA than respective 3-month-old rats. Fibronectin was higher in both control and WD 18-month-old males than respective 3-month-old males. In females, only control 18-month-old rats showed higher fibronectin than control 3-month-old rats. When we compared sex, control and WD 3-month-old female rats had lower expression of Slc12a3 mRNA than...
Aging is associated a decrease in thirst sensation, which makes old people more susceptible to de... more Aging is associated a decrease in thirst sensation, which makes old people more susceptible to dehydration. Dehydration produces energy metabolism alterations. Our objective was to determinate the effect of water deprivation (WD) in the lipid metabolism of old male and female rats. Here we show that in the state of WD, aging and sex alters retroperitoneal white adipose tissue (R-WAT) weight of rats, WD old female rats had more lipolysis products than old male rats, a sexual dimorphism in the hormonal response related with metabolism of the adipose tissue of old rats during WD, the expression of P-para mRNA in R-WAT did not present any alteration in animals submitted to WD, the expression of Aqp7 mRNA in R-WAT is altered by WD, age, and sex. Also, WD stimulated an increase in the plasma concentration of oxytocin and the expression of mRNA of the oxytocin receptors in R-WAT.
Aging changes body composition, energy balance and the network of signs that control homeostasis.... more Aging changes body composition, energy balance and the network of signs that control homeostasis. Objectives are: to characterize the aging of Wistar rats in relation to body composition and energetic homeostasis according to sex, to determine the changes produced by aging in renal and cardiovascular function, and to compare the hormonal and behavioral dipsogenic and natriorexigenic effects of aging, both in the normohydrate state and during water deprivation, and to identify whether these effects act equally on males and females. As experimental model was used male and female Wistar rats between 2 and 18-month-old. The oral glucose tolerance test and the fasting lipid profile were determined. With ad libitum feeding, the lipid profile, free fatty acids, glycemia and the dosage of leptin, adiponectin, insulin, corticosterone (CORT) and prolactin (PRL) were determined. Cardiac and renal function was determined at rest. Intake of water and sodium appetite, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), CORT, atrial natriuretic peptide (ANP) and angiotensin II (ANGII) in response to water deprivation. Old males presented alterations in glucose metabolism. In the prandial condition, the elderly males had higher serum levels of triglycerides, total cholesterol, HDL and free fatty acids. According to age, the elderly animals increased leptin, males increased adiponectin and females increased PRL and CORT. According to sex, insulin was highest in older males. Adiponectin and CORT were highest in 3 month-females, and elderly had highest PRL and CORT. The females presented diastolic dysfunction without changing the ejection fraction and the males altered the glomerular filtration rate. Old dehydrated animals drink less water and isotonic saline than young rats. Dehydrated 6 month-old-female ingested more saline than water, and 18 month-old-female drank more water than saline. Male drank at all ages more water than saline. During dehydration 3-month-rats had an increase in the plasma concentration of AVP, OT, ANGII and CORT, while the ANP decreased. In the 3-month males, when dehydrated the ANP was higher than in the dehydrated 3-month females. Dehydrated elderly animals had lower plasma concentrations of ANGII than 3-month-old animals. CORT was higher in older animals than in 3-month old animals. The plasma concentration of OT and CORT was higher in females than in older males. In conclusion, the major changes in energy metabolism are observed in old males, although old females can maintain energy homeostasis. Aged Wistar rats can be used for study renal and cardiac dysfunction. The dipsogenic and neuroendocrine behavioral response in the maintenance of the hydromineral homeostasis is influenced by aging, with sex being a preponderant factor in these responses.
17β-Estradiol (E2) has been shown to modulate the renin-angiotensin system in hydromineral and bl... more 17β-Estradiol (E2) has been shown to modulate the renin-angiotensin system in hydromineral and blood pressure homeostasis mainly by attenuating angiotensin II (ANGII) actions. However, the cellular mechanisms of the interaction between E2 and angiotensin II (ANGII) and its physiological role are largely unknown. The present experiments were performed to better understand the interaction between ANGII and E2 in body fluid control in female ovariectomized (OVX) rats. The present results are the first to demonstrate that PKC/p38 MAPK signaling is involved in ANGII-induced water and sodium intake and oxytocin (OT) secretion in OVX rats. In addition, previous data from our group revealed that the ANGII-induced vasopressin (AVP) secretion requires ERK1/2 signaling. Therefore, taken together, the present observations support a novel concept that distinct intracellular ANGII signaling gives rise to distinct neurohypophyseal hormone release. Furthermore, the results show that E2 attenuates p...
Objective. Protein tyrosine phosphatase 1B (PTP1B) has been extensively implicated in the regulat... more Objective. Protein tyrosine phosphatase 1B (PTP1B) has been extensively implicated in the regulation of body weight, food intake, and energy expenditure. The role of PTP1B appears to be cell and brain region dependent. Results. Herein, we demonstrated that chronic high-fat feeding enhanced PTP1B expression in the central nucleus of the amygdala (CeA) of rats compared to rats on chow. Knocking down PTP1B with oligonucleotide antisense (ASO) decreased its expression and was sufficient to improve the anorexigenic effect of insulin through IR/Akt signaling in the CeA. ASO treatment reduces body weight, fat mass, serum leptin levels, and food intake and also increases energy expenditure, without altering ambulatory activity. These changes were explained, at least in part, by the improvement of insulin sensitivity in the CeA, decreasing NPY and enhancing oxytocin expression. There was a slight decline in fasting blood glucose and serum insulin levels possibly due to leanness in rats treated with ASO. Surprisingly, the elevated plus maze test revealed an anxiolytic behavior after reduction of PTP1B in the CeA. Conclusions. Thus, the present study highlights the deleterious role that the amygdalar PTP1B has on energy homeostasis in obesity states. The reduction of PTP1B in the CeA may be a strategy for the treatment of obesity, insulin resistance and anxiety disorders.
Abstract Besides being studied regarding cardiovascular diseases and metabolic disturbances, litt... more Abstract Besides being studied regarding cardiovascular diseases and metabolic disturbances, little is known about how obesity might modulate the hydroeletroctrolytic balance. Some studies suggest that such modulation might exist. This current study has the objective of clarify the neuroendocrine mechanisms of salt and water homeostasis in obese rats under normal and osmotic challenge conditions. Wistar male rats weighting 100 grams were used; they were divided into two groups, one submitted to high fat diet (HFD) and the other submitted to normal diet, both for 9 weeks. After that they were kept in a metabolic cage for three days in order to measure food, water and sodium intake and urinary volume. After 24 or 48 hour fluid deprivation, they were given back water, in the first hour, and water and saline (1,8% NaCl), in the second hour, determining the ingestion of both fluids. One week later, the rats were submitted again to 24 or 48 hour fluid deprivation and then euthanized to obtain blood samples and tissues. During the basal period, the obese rats drank less water and ate less food than the non-obese rats. After the 24 or 48 hour dehydration, the obese rats drank less water than the non-obese. Besides that, the dehydrated obese rats also had a reduced hematocrit, reduced plasma osmolality, and reduced levels of K⁺ in plasma, a tendency to bigger levels of Na⁺ in plasma when compared to dehydrated non-obese rats. It was possible to observe an adipose tissue mass reduction in obese dehydrated rats when compared to obese hydrated rats. Accordingly, we were able to see that obesity indeed changes the hydroelectrolytic balance and there is the hypothesis that obese rats might use fat as a water reserve through of beta oxidation of lipids, which is an issue still under investigation. Sources of Research Support: Sao Paulo Research Foudation (FAPESP) Grant #2013/09799-1; Fapesp Grant #2018/10920-3.
Tesis (magister scientiae en bioquimica)--Universidad de Costa Rica. Sistema de Estudios de Posgr... more Tesis (magister scientiae en bioquimica)--Universidad de Costa Rica. Sistema de Estudios de Posgrado, 2007.
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses ... more Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses recruited to protect against osmotic stress are crucial for survival. The objective of this work was to compare the responses that occur in aging male and female rats during water deprivation. For this purpose, groups of male and female Wistar rats aged 3 mo (adults) or 18 mo (old) were submitted to water deprivation (WD) for 48 h. The water and sodium (0.15 M NaCl) intake, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), corticosterone (CORT), atrial natriuretic peptide (ANP), and angiotensin II (ANG II) were determined in hydrated and water-deprived animals. In response to WD, old male and female rats drank less water and saline than adults, and both adult and old females drank more water and saline than respective males. Dehydrated old animals displayed lower ANG II plasma concentration and CORT response compared with the respective normohydrated rats. Dehydrated ad...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses ... more Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses recruited to protect against osmotic stress are crucial for survival. The objective of this work was to compare the responses that occur in aging male and female rats during water deprivation. For this purpose, groups of male and female Wistar rats aged 3 mo (adults) or 18 mo (old) were submitted to water deprivation (WD) for 48 h. The water and sodium (0.15 M NaCl) intake, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), corticosterone (CORT), atrial natriuretic peptide (ANP), and angiotensin II (ANG II) were determined in hydrated and water-deprived animals. In response to WD, old male and female rats drank less water and saline than adults, and both adult and old females drank more water and saline than respective males. Dehydrated old animals displayed lower ANG II plasma concentration and CORT response compared with the respective normohydrated rats. Dehydrated ad...
Aging is a complex biological process, with gradual and progressive decline in structure and func... more Aging is a complex biological process, with gradual and progressive decline in structure and function in many organ systems. Our objective is to determine if structural changes produced by aging, vary with sex, in a stressful situation such as dehydration. The expression of Slc12a3 mRNA in renal cortex, α-smooth muscle actin (α-SMA) and fibronectin, was evaluated in male and female rats aged 3 and 18 months submitted or not to water deprivation (WD) for 48 hours. When comparing ages, 18-month-old males showed lower expression of Slc12a3 mRNA than 3-month-old males, and control and WD 18-moth-old male and female rats exhibited higher expression of α-SMA than respective 3-month-old rats. Fibronectin was higher in both control and WD 18-month-old males than respective 3-month-old males. In females, only control 18-month-old rats showed higher fibronectin than control 3-month-old rats. When we compared sex, control and WD 3-month-old female rats had lower expression of Slc12a3 mRNA than...
ABSTRACT
Introduction: The concept of “learning styles” derives from theories postulating that s... more ABSTRACT
Introduction: The concept of “learning styles” derives from theories postulating that students learn by following diverse pathways and that
learning is more effective when the adopted teaching strategies more closely match specific student characteristics and learning preferences.
Objectives: To determine, in first-year students attending different undergraduate courses in the health area at the same higher education
institution, the frequency of different learning styles, categorized according to the four dimensions of Felder & Soloman (FS) model, and to detect
any differences associated with the type of course and gender.
Method: The study population (N=283; 190 women) consisted of first-year students attending the Medicine, Biomedical Sciences, Physical Therapy,
Speech-Language Pathology, Nutrition and Metabolism, and Occupational Therapy courses, with 68.2% of them aged between 18 and 20 years.
The students answered a sociodemographic characterization questionnaire and the FS Index of Learning Styles (ILS) questionnaire, which allowed
determining the frequencies of the different learning styles and their associations with the type of undergraduate course and gender.
Results: the student group showed a predominance of “Sensory”, “Visual”, “Reflective” and “Sequential”, learning styles, in the “Perception”, “Input”,
“Processing” and “Understanding” dimensions of learning, respectively. There was no statistically significant difference in terms of learning styles,
in any of the dimensions, that could be associated with the type of course and gender, although women showed a significant predominance of
the “Reflective” style in the “Processing” dimension.
Conclusion: It was not possible to establish significant differences between the different undergraduate courses in the health area, or between
men and women, regarding the students’ predominant learning styles, although women showed a significantly higher frequency of the Reflective
style. These findings must be considered when planning learning activities and, mainly, in pedagogical support, giving students the opportunity
to learn about their learning styles and helping them to better adapt to the strategies employed in each institution.
Introduction: The concept of "learning styles" derives from theories postulating that students le... more Introduction: The concept of "learning styles" derives from theories postulating that students learn by following diverse pathways and that learning is more effective when the adopted teaching strategies more closely match specific student characteristics and learning preferences. Objectives: To determine, in first-year students attending different undergraduate courses in the health area at the same higher education institution, the frequency of different learning styles, categorized according to the four dimensions of Felder & Soloman (FS) model, and to detect any differences associated with the type of course and gender. Method: The study population (N=283; 190 women) consisted of first-year students attending the Medicine, Biomedical Sciences, Physical Therapy, Speech-Language Pathology, Nutrition and Metabolism, and Occupational Therapy courses, with 68.2% of them aged between 18 and 20 years. The students answered a sociodemographic characterization questionnaire and the FS Index of Learning Styles (ILS) questionnaire, which allowed determining the frequencies of the different learning styles and their associations with the type of undergraduate course and gender. Results: the student group showed a predominance of "Sensory", "Visual", "Reflective" and "Sequential", learning styles, in the "Perception", "Input", "Processing" and "Understanding" dimensions of learning, respectively. There was no statistically significant difference in terms of learning styles, in any of the dimensions, that could be associated with the type of course and gender, although women showed a significant predominance of the "Reflective" style in the "Processing" dimension. Conclusion: It was not possible to establish significant differences between the different undergraduate courses in the health area, or between men and women, regarding the students' predominant learning styles, although women showed a significantly higher frequency of the Reflective style. These findings must be considered when planning learning activities and, mainly, in pedagogical support, giving students the opportunity to learn about their learning styles and helping them to better adapt to the strategies employed in each institution.
Aging is a complex biological process, with gradual and progressive decline in structure and func... more Aging is a complex biological process, with gradual and progressive decline in structure and function in many organ systems. Our objective is to determine if structural changes produced by aging, vary with sex, in a stressful situation such as dehydration. The expression of Slc12a3 mRNA in renal cortex, α-smooth muscle actin (α-SMA) and fibronectin, was evaluated in male and female rats aged 3 and 18 months submitted or not to water deprivation (WD) for 48 hours. When comparing ages, 18-month-old males showed lower expression of Slc12a3 mRNA than 3-month-old males, and control and WD 18-moth-old male and female rats exhibited higher expression of α-SMA than respective 3-month-old rats. Fibronectin was higher in both control and WD 18-month-old males than respective 3-month-old males. In females, only control 18-month-old rats showed higher fibronectin than control 3-month-old rats. When we compared sex, control and WD 3-month-old female rats had lower expression of Slc12a3 mRNA than...
Aging is associated a decrease in thirst sensation, which makes old people more susceptible to de... more Aging is associated a decrease in thirst sensation, which makes old people more susceptible to dehydration. Dehydration produces energy metabolism alterations. Our objective was to determinate the effect of water deprivation (WD) in the lipid metabolism of old male and female rats. Here we show that in the state of WD, aging and sex alters retroperitoneal white adipose tissue (R-WAT) weight of rats, WD old female rats had more lipolysis products than old male rats, a sexual dimorphism in the hormonal response related with metabolism of the adipose tissue of old rats during WD, the expression of P-para mRNA in R-WAT did not present any alteration in animals submitted to WD, the expression of Aqp7 mRNA in R-WAT is altered by WD, age, and sex. Also, WD stimulated an increase in the plasma concentration of oxytocin and the expression of mRNA of the oxytocin receptors in R-WAT.
Aging changes body composition, energy balance and the network of signs that control homeostasis.... more Aging changes body composition, energy balance and the network of signs that control homeostasis. Objectives are: to characterize the aging of Wistar rats in relation to body composition and energetic homeostasis according to sex, to determine the changes produced by aging in renal and cardiovascular function, and to compare the hormonal and behavioral dipsogenic and natriorexigenic effects of aging, both in the normohydrate state and during water deprivation, and to identify whether these effects act equally on males and females. As experimental model was used male and female Wistar rats between 2 and 18-month-old. The oral glucose tolerance test and the fasting lipid profile were determined. With ad libitum feeding, the lipid profile, free fatty acids, glycemia and the dosage of leptin, adiponectin, insulin, corticosterone (CORT) and prolactin (PRL) were determined. Cardiac and renal function was determined at rest. Intake of water and sodium appetite, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), CORT, atrial natriuretic peptide (ANP) and angiotensin II (ANGII) in response to water deprivation. Old males presented alterations in glucose metabolism. In the prandial condition, the elderly males had higher serum levels of triglycerides, total cholesterol, HDL and free fatty acids. According to age, the elderly animals increased leptin, males increased adiponectin and females increased PRL and CORT. According to sex, insulin was highest in older males. Adiponectin and CORT were highest in 3 month-females, and elderly had highest PRL and CORT. The females presented diastolic dysfunction without changing the ejection fraction and the males altered the glomerular filtration rate. Old dehydrated animals drink less water and isotonic saline than young rats. Dehydrated 6 month-old-female ingested more saline than water, and 18 month-old-female drank more water than saline. Male drank at all ages more water than saline. During dehydration 3-month-rats had an increase in the plasma concentration of AVP, OT, ANGII and CORT, while the ANP decreased. In the 3-month males, when dehydrated the ANP was higher than in the dehydrated 3-month females. Dehydrated elderly animals had lower plasma concentrations of ANGII than 3-month-old animals. CORT was higher in older animals than in 3-month old animals. The plasma concentration of OT and CORT was higher in females than in older males. In conclusion, the major changes in energy metabolism are observed in old males, although old females can maintain energy homeostasis. Aged Wistar rats can be used for study renal and cardiac dysfunction. The dipsogenic and neuroendocrine behavioral response in the maintenance of the hydromineral homeostasis is influenced by aging, with sex being a preponderant factor in these responses.
17β-Estradiol (E2) has been shown to modulate the renin-angiotensin system in hydromineral and bl... more 17β-Estradiol (E2) has been shown to modulate the renin-angiotensin system in hydromineral and blood pressure homeostasis mainly by attenuating angiotensin II (ANGII) actions. However, the cellular mechanisms of the interaction between E2 and angiotensin II (ANGII) and its physiological role are largely unknown. The present experiments were performed to better understand the interaction between ANGII and E2 in body fluid control in female ovariectomized (OVX) rats. The present results are the first to demonstrate that PKC/p38 MAPK signaling is involved in ANGII-induced water and sodium intake and oxytocin (OT) secretion in OVX rats. In addition, previous data from our group revealed that the ANGII-induced vasopressin (AVP) secretion requires ERK1/2 signaling. Therefore, taken together, the present observations support a novel concept that distinct intracellular ANGII signaling gives rise to distinct neurohypophyseal hormone release. Furthermore, the results show that E2 attenuates p...
Objective. Protein tyrosine phosphatase 1B (PTP1B) has been extensively implicated in the regulat... more Objective. Protein tyrosine phosphatase 1B (PTP1B) has been extensively implicated in the regulation of body weight, food intake, and energy expenditure. The role of PTP1B appears to be cell and brain region dependent. Results. Herein, we demonstrated that chronic high-fat feeding enhanced PTP1B expression in the central nucleus of the amygdala (CeA) of rats compared to rats on chow. Knocking down PTP1B with oligonucleotide antisense (ASO) decreased its expression and was sufficient to improve the anorexigenic effect of insulin through IR/Akt signaling in the CeA. ASO treatment reduces body weight, fat mass, serum leptin levels, and food intake and also increases energy expenditure, without altering ambulatory activity. These changes were explained, at least in part, by the improvement of insulin sensitivity in the CeA, decreasing NPY and enhancing oxytocin expression. There was a slight decline in fasting blood glucose and serum insulin levels possibly due to leanness in rats treated with ASO. Surprisingly, the elevated plus maze test revealed an anxiolytic behavior after reduction of PTP1B in the CeA. Conclusions. Thus, the present study highlights the deleterious role that the amygdalar PTP1B has on energy homeostasis in obesity states. The reduction of PTP1B in the CeA may be a strategy for the treatment of obesity, insulin resistance and anxiety disorders.
Abstract Besides being studied regarding cardiovascular diseases and metabolic disturbances, litt... more Abstract Besides being studied regarding cardiovascular diseases and metabolic disturbances, little is known about how obesity might modulate the hydroeletroctrolytic balance. Some studies suggest that such modulation might exist. This current study has the objective of clarify the neuroendocrine mechanisms of salt and water homeostasis in obese rats under normal and osmotic challenge conditions. Wistar male rats weighting 100 grams were used; they were divided into two groups, one submitted to high fat diet (HFD) and the other submitted to normal diet, both for 9 weeks. After that they were kept in a metabolic cage for three days in order to measure food, water and sodium intake and urinary volume. After 24 or 48 hour fluid deprivation, they were given back water, in the first hour, and water and saline (1,8% NaCl), in the second hour, determining the ingestion of both fluids. One week later, the rats were submitted again to 24 or 48 hour fluid deprivation and then euthanized to obtain blood samples and tissues. During the basal period, the obese rats drank less water and ate less food than the non-obese rats. After the 24 or 48 hour dehydration, the obese rats drank less water than the non-obese. Besides that, the dehydrated obese rats also had a reduced hematocrit, reduced plasma osmolality, and reduced levels of K⁺ in plasma, a tendency to bigger levels of Na⁺ in plasma when compared to dehydrated non-obese rats. It was possible to observe an adipose tissue mass reduction in obese dehydrated rats when compared to obese hydrated rats. Accordingly, we were able to see that obesity indeed changes the hydroelectrolytic balance and there is the hypothesis that obese rats might use fat as a water reserve through of beta oxidation of lipids, which is an issue still under investigation. Sources of Research Support: Sao Paulo Research Foudation (FAPESP) Grant #2013/09799-1; Fapesp Grant #2018/10920-3.
Tesis (magister scientiae en bioquimica)--Universidad de Costa Rica. Sistema de Estudios de Posgr... more Tesis (magister scientiae en bioquimica)--Universidad de Costa Rica. Sistema de Estudios de Posgrado, 2007.
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses ... more Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses recruited to protect against osmotic stress are crucial for survival. The objective of this work was to compare the responses that occur in aging male and female rats during water deprivation. For this purpose, groups of male and female Wistar rats aged 3 mo (adults) or 18 mo (old) were submitted to water deprivation (WD) for 48 h. The water and sodium (0.15 M NaCl) intake, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), corticosterone (CORT), atrial natriuretic peptide (ANP), and angiotensin II (ANG II) were determined in hydrated and water-deprived animals. In response to WD, old male and female rats drank less water and saline than adults, and both adult and old females drank more water and saline than respective males. Dehydrated old animals displayed lower ANG II plasma concentration and CORT response compared with the respective normohydrated rats. Dehydrated ad...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses ... more Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses recruited to protect against osmotic stress are crucial for survival. The objective of this work was to compare the responses that occur in aging male and female rats during water deprivation. For this purpose, groups of male and female Wistar rats aged 3 mo (adults) or 18 mo (old) were submitted to water deprivation (WD) for 48 h. The water and sodium (0.15 M NaCl) intake, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), corticosterone (CORT), atrial natriuretic peptide (ANP), and angiotensin II (ANG II) were determined in hydrated and water-deprived animals. In response to WD, old male and female rats drank less water and saline than adults, and both adult and old females drank more water and saline than respective males. Dehydrated old animals displayed lower ANG II plasma concentration and CORT response compared with the respective normohydrated rats. Dehydrated ad...
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Papers by Susana Cognuck
Introduction: The concept of “learning styles” derives from theories postulating that students learn by following diverse pathways and that
learning is more effective when the adopted teaching strategies more closely match specific student characteristics and learning preferences.
Objectives: To determine, in first-year students attending different undergraduate courses in the health area at the same higher education
institution, the frequency of different learning styles, categorized according to the four dimensions of Felder & Soloman (FS) model, and to detect
any differences associated with the type of course and gender.
Method: The study population (N=283; 190 women) consisted of first-year students attending the Medicine, Biomedical Sciences, Physical Therapy,
Speech-Language Pathology, Nutrition and Metabolism, and Occupational Therapy courses, with 68.2% of them aged between 18 and 20 years.
The students answered a sociodemographic characterization questionnaire and the FS Index of Learning Styles (ILS) questionnaire, which allowed
determining the frequencies of the different learning styles and their associations with the type of undergraduate course and gender.
Results: the student group showed a predominance of “Sensory”, “Visual”, “Reflective” and “Sequential”, learning styles, in the “Perception”, “Input”,
“Processing” and “Understanding” dimensions of learning, respectively. There was no statistically significant difference in terms of learning styles,
in any of the dimensions, that could be associated with the type of course and gender, although women showed a significant predominance of
the “Reflective” style in the “Processing” dimension.
Conclusion: It was not possible to establish significant differences between the different undergraduate courses in the health area, or between
men and women, regarding the students’ predominant learning styles, although women showed a significantly higher frequency of the Reflective
style. These findings must be considered when planning learning activities and, mainly, in pedagogical support, giving students the opportunity
to learn about their learning styles and helping them to better adapt to the strategies employed in each institution.
Introduction: The concept of “learning styles” derives from theories postulating that students learn by following diverse pathways and that
learning is more effective when the adopted teaching strategies more closely match specific student characteristics and learning preferences.
Objectives: To determine, in first-year students attending different undergraduate courses in the health area at the same higher education
institution, the frequency of different learning styles, categorized according to the four dimensions of Felder & Soloman (FS) model, and to detect
any differences associated with the type of course and gender.
Method: The study population (N=283; 190 women) consisted of first-year students attending the Medicine, Biomedical Sciences, Physical Therapy,
Speech-Language Pathology, Nutrition and Metabolism, and Occupational Therapy courses, with 68.2% of them aged between 18 and 20 years.
The students answered a sociodemographic characterization questionnaire and the FS Index of Learning Styles (ILS) questionnaire, which allowed
determining the frequencies of the different learning styles and their associations with the type of undergraduate course and gender.
Results: the student group showed a predominance of “Sensory”, “Visual”, “Reflective” and “Sequential”, learning styles, in the “Perception”, “Input”,
“Processing” and “Understanding” dimensions of learning, respectively. There was no statistically significant difference in terms of learning styles,
in any of the dimensions, that could be associated with the type of course and gender, although women showed a significant predominance of
the “Reflective” style in the “Processing” dimension.
Conclusion: It was not possible to establish significant differences between the different undergraduate courses in the health area, or between
men and women, regarding the students’ predominant learning styles, although women showed a significantly higher frequency of the Reflective
style. These findings must be considered when planning learning activities and, mainly, in pedagogical support, giving students the opportunity
to learn about their learning styles and helping them to better adapt to the strategies employed in each institution.