Pablo Tapia - Academia.edu (original) (raw)
Papers by Pablo Tapia
North American Journal of Aquaculture, 2012
The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform... more The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform fish found in the eastern Pacific Ocean. In northern Chile, San Pedro are an important food fish currently being evaluated for aquaculture. The purpose of this study was to conduct an initial evaluation of the cortisol stress response in captive-bred San Pedro. The fish were subjected to confinement stress by crowding them into a low volume of water (231 kg/m3) for 90 min. Blood was collected over time for the determination of plasma cortisol. Confinement resulted in a significant increase in plasma cortisol, from a resting concentration of 24.9 ng/mL to 120.7 ng/mL after 10 min into the stress experience. After 20 and 60 min of stress, cortisol concentrations plateaued at 225.3 ng/mL and 243.7 ng/mL, respectively, followed by a decrease to 56.1 ng/mL by 90 min. These results indicate a rapid and robust cortisol stress response in this species. This is the first evaluation of the San Pedro stress response, and these data will serve as the baseline for future evaluations of San Pedro stress physiology and the development of aquaculture techniques suitable for this species.Received December 9, 2011; accepted January 30, 2012
Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, ... more Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, miners, and observatory, rural health, border patrol, and rural education workers, jeopardizes normal physiologic functions in humans. The present study was conducted to evaluate the effects of intermittent HH (IHH; equivalent to 4600 m above mean sea level) on oxidative stress and the protective role of dietary ascorbic acid on rat testis and epididymis. Ten-week-old male Wistar rats were assigned to 1 of 6 groups: 1) normobaric (Nx), 2) Nx + physiologic solution (Nx + PS), 3) Nx + ascorbic acid (Nx + AA), 4) IHH, 5) IHH + PS, or 6) IHH + AA. Animals subjected to IHH were exposed for 96 hours followed by normobaric conditions for 96 hours for a total of 32 days. The control groups (2 and 5) were injected with doses of PS, and the treated groups (3 and 6) were injected with doses of AA (10 mg 6kg 21 body weight) at an interval of 96 hours. Rats were sacrificed on day 32 after initiation of the protocol. The testis and epididymis were collected to determine the activity and expression of glutathione reductase and the levels of lipid peroxide formation. An epididymal sperm count was also performed in each animal. The results of this study revealed that IHH induced lipid peroxidation, a reduction in glutathione reductase activity in testis and epididymis, and a significant decrease in epididymal sperm count. Treatment with AA prevented these changes. In conclusion, AA was capable of decreasing oxidative stress in testis and epididymis under IHH. This protection by AA of the IHH-induced lipid peroxidation can be explained in part by the preservation of glutathione reductase activity in these organs.
North American Journal of Aquaculture, 2012
The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform... more The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform fish found in the eastern Pacific Ocean. In northern Chile, San Pedro are an important food fish currently being evaluated for aquaculture. The purpose of this study was to conduct an initial evaluation of the cortisol stress response in captive-bred San Pedro. The fish were subjected to confinement stress by crowding them into a low volume of water (231 kg/m 3 ) for 90 min. Blood was collected over time for the determination of plasma cortisol. Confinement resulted in a significant increase in plasma cortisol, from a resting concentration of 24.9 ng/mL to 120.7 ng/mL after 10 min into the stress experience. After 20 and 60 min of stress, cortisol concentrations plateaued at 225.3 ng/mL and 243.7 ng/mL, respectively, followed by a decrease to 56.1 ng/mL by 90 min. These results indicate a rapid and robust cortisol stress response in this species. This is the first evaluation of the San Pedro stress response, and these data will serve as the baseline for future evaluations of San Pedro stress physiology and the development of aquaculture techniques suitable for this species.
Time Course of Endocrine Changes in the Hypophysis-Gonad Axis Induced by Hypobaric Hypoxia in Male Rats
Journal of Reproduction and Development, 2008
Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male ra... more Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male rats. The mechanisms that underlie these changes in testicular function are unknown and could involve changes in the hypophysis-gonad axis. We have tested the hypothesis that changes take place in the endocrine status (FSH, follicle stimulating hormone; LH, luteinizing hormone; testosterone) of rats subjected to CHH. Male Wistar rats were maintained under normobaric or hypobaric conditions (428 torr, 4,600 m). On days 0, 5, 15 and 30 post-exposure, 12 rats were anesthetized, their body weights were measured and blood samples were collected. The testicles were fixed in 4% formaldehyde and processed for histological analysis. In this time course, the FSH levels rose by day 5 post-exposure. On subsequent days, the FSH levels decreased in rats subjected to CHH with a tendency to remain higher than the normoxic group. The LH plasma levels decreased in rats exposed to CHH. Consistent with the decrease in LH levels, the plasma testosterone level decreased significantly after 30 days of CHH exposure. Integrated analysis of hormonal changes in rats subjected to CHH and the body dehydration that occurs in HH allows us to conclude that the effects of CHH on spermatogenesis may be partially related to changes in the hypophysis-gonad hormonal axis.
Time Course of Endocrine Changes in the Hypophysis-Gonad Axis Induced by Hypobaric Hypoxia in Male Rats
Journal of Reproduction and Development, 2008
Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male ra... more Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male rats. The mechanisms that underlie these changes in testicular function are unknown and could involve changes in the hypophysis-gonad axis. We have tested the hypothesis that changes take place in the endocrine status (FSH, follicle stimulating hormone; LH, luteinizing hormone; testosterone) of rats subjected to CHH. Male Wistar rats were maintained under normobaric or hypobaric conditions (428 torr, 4,600 m). On days 0, 5, 15 and 30 post-exposure, 12 rats were anesthetized, their body weights were measured and blood samples were collected. The testicles were fixed in 4% formaldehyde and processed for histological analysis. In this time course, the FSH levels rose by day 5 post-exposure. On subsequent days, the FSH levels decreased in rats subjected to CHH with a tendency to remain higher than the normoxic group. The LH plasma levels decreased in rats exposed to CHH. Consistent with the decrease in LH levels, the plasma testosterone level decreased significantly after 30 days of CHH exposure. Integrated analysis of hormonal changes in rats subjected to CHH and the body dehydration that occurs in HH allows us to conclude that the effects of CHH on spermatogenesis may be partially related to changes in the hypophysis-gonad hormonal axis.
Journal of Andrology, 2010
Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, ... more Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, miners, and observatory, rural health, border patrol, and rural education workers, jeopardizes normal physiologic functions in humans. The present study was conducted to evaluate the effects of intermittent HH (IHH; equivalent to 4600 m above mean sea level) on oxidative stress and the protective role of dietary ascorbic acid on rat testis and epididymis. Ten-week-old male Wistar rats were assigned to 1 of 6 groups: 1) normobaric (Nx), 2) Nx + physiologic solution (Nx + PS), 3) Nx + ascorbic acid (Nx + AA), 4) IHH, 5) IHH + PS, or 6) IHH + AA. Animals subjected to IHH were exposed for 96 hours followed by normobaric conditions for 96 hours for a total of 32 days. The control groups (2 and 5) were injected with doses of PS, and the treated groups (3 and 6) were injected with doses of AA (10 mg 6kg 21 body weight) at an interval of 96 hours. Rats were sacrificed on day 32 after initiation of the protocol. The testis and epididymis were collected to determine the activity and expression of glutathione reductase and the levels of lipid peroxide formation. An epididymal sperm count was also performed in each animal. The results of this study revealed that IHH induced lipid peroxidation, a reduction in glutathione reductase activity in testis and epididymis, and a significant decrease in epididymal sperm count. Treatment with AA prevented these changes. In conclusion, AA was capable of decreasing oxidative stress in testis and epididymis under IHH. This protection by AA of the IHH-induced lipid peroxidation can be explained in part by the preservation of glutathione reductase activity in these organs.
Infection and immunity, 2014
21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the b... more 21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the bloodstream and interact with endothelial cells (ECs), inducing dysfunction of the 24 ECs. We have previously reported that endotoxins induce the conversion of ECs into 25 activated fibroblasts. Through endotoxin-induced endothelial fibrosis, ECs change their 26 morphology and their protein pattern expression, thereby suppressing endothelial markers 27 and upregulating fibrotic proteins. The most commonly used fibrotic inducers are TGF-β1 28 and TGF-β2. However, whether TGF-β1 and TGF-β2 participate in endotoxin-induced 29 endothelial fibrosis remains unknown. We have shown that the endotoxin-induced 30 endothelial fibrosis process is dependent on the TGF-β receptor, ALK5, and the activation 31 of Smad3, a protein that is activated by ALK5 activation, thus suggesting that endotoxin 32 elicits TGF-β production to mediate endotoxin-induced endothelial fibrosis. Therefore, we 33 investigated the dependence of endotoxin-induced endothelial fibrosis on the expression of 34 TGF-β1 and TGF-β2. 35 Endotoxin-treated ECs induced the expression and secretion of TGF-β1 and TGF-36 β2. TGF-β1 and TGF-β2 downregulation inhibited the endotoxin-induced changes in the 37 endothelial marker, VE-cadherin, and in the fibrotic proteins, α-SMA and fibronectin.
Infection and Immunity
21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the b... more 21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the bloodstream and interact with endothelial cells (ECs), inducing dysfunction of the 24 ECs. We have previously reported that endotoxins induce the conversion of ECs into 25 activated fibroblasts. Through endotoxin-induced endothelial fibrosis, ECs change their 26 morphology and their protein pattern expression, thereby suppressing endothelial markers 27 and upregulating fibrotic proteins. The most commonly used fibrotic inducers are TGF-β1 28 and TGF-β2. However, whether TGF-β1 and TGF-β2 participate in endotoxin-induced 29 endothelial fibrosis remains unknown. We have shown that the endotoxin-induced 30 endothelial fibrosis process is dependent on the TGF-β receptor, ALK5, and the activation 31 of Smad3, a protein that is activated by ALK5 activation, thus suggesting that endotoxin 32 elicits TGF-β production to mediate endotoxin-induced endothelial fibrosis. Therefore, we 33 investigated the dependence of endotoxin-induced endothelial fibrosis on the expression of 34 TGF-β1 and TGF-β2. 35 Endotoxin-treated ECs induced the expression and secretion of TGF-β1 and TGF-36 β2. TGF-β1 and TGF-β2 downregulation inhibited the endotoxin-induced changes in the 37 endothelial marker, VE-cadherin, and in the fibrotic proteins, α-SMA and fibronectin.
La Petrofísica es de suma importancia en el estudio de los Campos Petroleros para la búsqueda de ... more La Petrofísica es de suma importancia en el estudio de los Campos Petroleros para la búsqueda de petróleo y gas; y más aún para el cálculo de las propiedades de las rocas como son contenido de fluido, porosidad, presión y permeabilidad a partir de las mediciones de sus propiedades físicas ya sea resistencia y radiación natural.
North American Journal of Aquaculture, 2012
The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform... more The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform fish found in the eastern Pacific Ocean. In northern Chile, San Pedro are an important food fish currently being evaluated for aquaculture. The purpose of this study was to conduct an initial evaluation of the cortisol stress response in captive-bred San Pedro. The fish were subjected to confinement stress by crowding them into a low volume of water (231 kg/m3) for 90 min. Blood was collected over time for the determination of plasma cortisol. Confinement resulted in a significant increase in plasma cortisol, from a resting concentration of 24.9 ng/mL to 120.7 ng/mL after 10 min into the stress experience. After 20 and 60 min of stress, cortisol concentrations plateaued at 225.3 ng/mL and 243.7 ng/mL, respectively, followed by a decrease to 56.1 ng/mL by 90 min. These results indicate a rapid and robust cortisol stress response in this species. This is the first evaluation of the San Pedro stress response, and these data will serve as the baseline for future evaluations of San Pedro stress physiology and the development of aquaculture techniques suitable for this species.Received December 9, 2011; accepted January 30, 2012
Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, ... more Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, miners, and observatory, rural health, border patrol, and rural education workers, jeopardizes normal physiologic functions in humans. The present study was conducted to evaluate the effects of intermittent HH (IHH; equivalent to 4600 m above mean sea level) on oxidative stress and the protective role of dietary ascorbic acid on rat testis and epididymis. Ten-week-old male Wistar rats were assigned to 1 of 6 groups: 1) normobaric (Nx), 2) Nx + physiologic solution (Nx + PS), 3) Nx + ascorbic acid (Nx + AA), 4) IHH, 5) IHH + PS, or 6) IHH + AA. Animals subjected to IHH were exposed for 96 hours followed by normobaric conditions for 96 hours for a total of 32 days. The control groups (2 and 5) were injected with doses of PS, and the treated groups (3 and 6) were injected with doses of AA (10 mg 6kg 21 body weight) at an interval of 96 hours. Rats were sacrificed on day 32 after initiation of the protocol. The testis and epididymis were collected to determine the activity and expression of glutathione reductase and the levels of lipid peroxide formation. An epididymal sperm count was also performed in each animal. The results of this study revealed that IHH induced lipid peroxidation, a reduction in glutathione reductase activity in testis and epididymis, and a significant decrease in epididymal sperm count. Treatment with AA prevented these changes. In conclusion, AA was capable of decreasing oxidative stress in testis and epididymis under IHH. This protection by AA of the IHH-induced lipid peroxidation can be explained in part by the preservation of glutathione reductase activity in these organs.
North American Journal of Aquaculture, 2012
The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform... more The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform fish found in the eastern Pacific Ocean. In northern Chile, San Pedro are an important food fish currently being evaluated for aquaculture. The purpose of this study was to conduct an initial evaluation of the cortisol stress response in captive-bred San Pedro. The fish were subjected to confinement stress by crowding them into a low volume of water (231 kg/m 3 ) for 90 min. Blood was collected over time for the determination of plasma cortisol. Confinement resulted in a significant increase in plasma cortisol, from a resting concentration of 24.9 ng/mL to 120.7 ng/mL after 10 min into the stress experience. After 20 and 60 min of stress, cortisol concentrations plateaued at 225.3 ng/mL and 243.7 ng/mL, respectively, followed by a decrease to 56.1 ng/mL by 90 min. These results indicate a rapid and robust cortisol stress response in this species. This is the first evaluation of the San Pedro stress response, and these data will serve as the baseline for future evaluations of San Pedro stress physiology and the development of aquaculture techniques suitable for this species.
Time Course of Endocrine Changes in the Hypophysis-Gonad Axis Induced by Hypobaric Hypoxia in Male Rats
Journal of Reproduction and Development, 2008
Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male ra... more Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male rats. The mechanisms that underlie these changes in testicular function are unknown and could involve changes in the hypophysis-gonad axis. We have tested the hypothesis that changes take place in the endocrine status (FSH, follicle stimulating hormone; LH, luteinizing hormone; testosterone) of rats subjected to CHH. Male Wistar rats were maintained under normobaric or hypobaric conditions (428 torr, 4,600 m). On days 0, 5, 15 and 30 post-exposure, 12 rats were anesthetized, their body weights were measured and blood samples were collected. The testicles were fixed in 4% formaldehyde and processed for histological analysis. In this time course, the FSH levels rose by day 5 post-exposure. On subsequent days, the FSH levels decreased in rats subjected to CHH with a tendency to remain higher than the normoxic group. The LH plasma levels decreased in rats exposed to CHH. Consistent with the decrease in LH levels, the plasma testosterone level decreased significantly after 30 days of CHH exposure. Integrated analysis of hormonal changes in rats subjected to CHH and the body dehydration that occurs in HH allows us to conclude that the effects of CHH on spermatogenesis may be partially related to changes in the hypophysis-gonad hormonal axis.
Time Course of Endocrine Changes in the Hypophysis-Gonad Axis Induced by Hypobaric Hypoxia in Male Rats
Journal of Reproduction and Development, 2008
Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male ra... more Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male rats. The mechanisms that underlie these changes in testicular function are unknown and could involve changes in the hypophysis-gonad axis. We have tested the hypothesis that changes take place in the endocrine status (FSH, follicle stimulating hormone; LH, luteinizing hormone; testosterone) of rats subjected to CHH. Male Wistar rats were maintained under normobaric or hypobaric conditions (428 torr, 4,600 m). On days 0, 5, 15 and 30 post-exposure, 12 rats were anesthetized, their body weights were measured and blood samples were collected. The testicles were fixed in 4% formaldehyde and processed for histological analysis. In this time course, the FSH levels rose by day 5 post-exposure. On subsequent days, the FSH levels decreased in rats subjected to CHH with a tendency to remain higher than the normoxic group. The LH plasma levels decreased in rats exposed to CHH. Consistent with the decrease in LH levels, the plasma testosterone level decreased significantly after 30 days of CHH exposure. Integrated analysis of hormonal changes in rats subjected to CHH and the body dehydration that occurs in HH allows us to conclude that the effects of CHH on spermatogenesis may be partially related to changes in the hypophysis-gonad hormonal axis.
Journal of Andrology, 2010
Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, ... more Hypobaric hypoxia (HH), an environmental condition of high altitude encountered by mountaineers, miners, and observatory, rural health, border patrol, and rural education workers, jeopardizes normal physiologic functions in humans. The present study was conducted to evaluate the effects of intermittent HH (IHH; equivalent to 4600 m above mean sea level) on oxidative stress and the protective role of dietary ascorbic acid on rat testis and epididymis. Ten-week-old male Wistar rats were assigned to 1 of 6 groups: 1) normobaric (Nx), 2) Nx + physiologic solution (Nx + PS), 3) Nx + ascorbic acid (Nx + AA), 4) IHH, 5) IHH + PS, or 6) IHH + AA. Animals subjected to IHH were exposed for 96 hours followed by normobaric conditions for 96 hours for a total of 32 days. The control groups (2 and 5) were injected with doses of PS, and the treated groups (3 and 6) were injected with doses of AA (10 mg 6kg 21 body weight) at an interval of 96 hours. Rats were sacrificed on day 32 after initiation of the protocol. The testis and epididymis were collected to determine the activity and expression of glutathione reductase and the levels of lipid peroxide formation. An epididymal sperm count was also performed in each animal. The results of this study revealed that IHH induced lipid peroxidation, a reduction in glutathione reductase activity in testis and epididymis, and a significant decrease in epididymal sperm count. Treatment with AA prevented these changes. In conclusion, AA was capable of decreasing oxidative stress in testis and epididymis under IHH. This protection by AA of the IHH-induced lipid peroxidation can be explained in part by the preservation of glutathione reductase activity in these organs.
Infection and immunity, 2014
21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the b... more 21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the bloodstream and interact with endothelial cells (ECs), inducing dysfunction of the 24 ECs. We have previously reported that endotoxins induce the conversion of ECs into 25 activated fibroblasts. Through endotoxin-induced endothelial fibrosis, ECs change their 26 morphology and their protein pattern expression, thereby suppressing endothelial markers 27 and upregulating fibrotic proteins. The most commonly used fibrotic inducers are TGF-β1 28 and TGF-β2. However, whether TGF-β1 and TGF-β2 participate in endotoxin-induced 29 endothelial fibrosis remains unknown. We have shown that the endotoxin-induced 30 endothelial fibrosis process is dependent on the TGF-β receptor, ALK5, and the activation 31 of Smad3, a protein that is activated by ALK5 activation, thus suggesting that endotoxin 32 elicits TGF-β production to mediate endotoxin-induced endothelial fibrosis. Therefore, we 33 investigated the dependence of endotoxin-induced endothelial fibrosis on the expression of 34 TGF-β1 and TGF-β2. 35 Endotoxin-treated ECs induced the expression and secretion of TGF-β1 and TGF-36 β2. TGF-β1 and TGF-β2 downregulation inhibited the endotoxin-induced changes in the 37 endothelial marker, VE-cadherin, and in the fibrotic proteins, α-SMA and fibronectin.
Infection and Immunity
21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the b... more 21 22 During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate 23 in the bloodstream and interact with endothelial cells (ECs), inducing dysfunction of the 24 ECs. We have previously reported that endotoxins induce the conversion of ECs into 25 activated fibroblasts. Through endotoxin-induced endothelial fibrosis, ECs change their 26 morphology and their protein pattern expression, thereby suppressing endothelial markers 27 and upregulating fibrotic proteins. The most commonly used fibrotic inducers are TGF-β1 28 and TGF-β2. However, whether TGF-β1 and TGF-β2 participate in endotoxin-induced 29 endothelial fibrosis remains unknown. We have shown that the endotoxin-induced 30 endothelial fibrosis process is dependent on the TGF-β receptor, ALK5, and the activation 31 of Smad3, a protein that is activated by ALK5 activation, thus suggesting that endotoxin 32 elicits TGF-β production to mediate endotoxin-induced endothelial fibrosis. Therefore, we 33 investigated the dependence of endotoxin-induced endothelial fibrosis on the expression of 34 TGF-β1 and TGF-β2. 35 Endotoxin-treated ECs induced the expression and secretion of TGF-β1 and TGF-36 β2. TGF-β1 and TGF-β2 downregulation inhibited the endotoxin-induced changes in the 37 endothelial marker, VE-cadherin, and in the fibrotic proteins, α-SMA and fibronectin.
La Petrofísica es de suma importancia en el estudio de los Campos Petroleros para la búsqueda de ... more La Petrofísica es de suma importancia en el estudio de los Campos Petroleros para la búsqueda de petróleo y gas; y más aún para el cálculo de las propiedades de las rocas como son contenido de fluido, porosidad, presión y permeabilidad a partir de las mediciones de sus propiedades físicas ya sea resistencia y radiación natural.