AIM: To study the blood-brain barrier integrity, brain edema,animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication.METHODS: Adults male Wistar rats ...AIM: To study the blood-brain barrier integrity, brain edema,animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication.METHODS: Adults male Wistar rats were divided into four groups. Group I: sham operation; II: Prehepatic portal hypertension, produced by partial portal vein ligation; III:Acetaminophen intoxication and IV: Prehepatic portal hypertension plus acetaminophen. Acetaminophen was administered to produce acute hepatic injury. Portal pressure, liver serum enzymes and ammonia plasma levels were determined. Brain cortex water content was registered and trypan blue was utilized to study blood brain barrier integrity. Reflexes and behavioral tests were recorded.RESULTS: Portal hypertension was significantly elevated in groups II and IV. Liver enzymes and ammonia plasma levels were increased in groups II, III and IV. Prehepatic portal hypertension (group II), acetaminophen intoxication (group III) and both (group IV) had changes in the blood brain-barrier integrity (trypan blue) and hyperammonemia. Cortical edema was present in rats with acute hepatic injury in groups III and IV. Behavioral test (rota rod) was altered in group IV.CONCLUSION: These results suggest the possibility of another pathway for cortical edema production because blood brain barrier was altered (vasogenic) and hyperammonemia was registered (cytotoxic). Group IV, with behavioral altered test, can be considered as a model for study at an early stage of portal-systemic encephalopathy.展开更多
AIM To determine the effect of tempol in normal rats fed high salt on arterial pressure and the balance between antagonist components of the renal renin-angiotensin system.METHODS Sprague-Dawley rats were fed with 8% ...AIM To determine the effect of tempol in normal rats fed high salt on arterial pressure and the balance between antagonist components of the renal renin-angiotensin system.METHODS Sprague-Dawley rats were fed with 8% Na Cl highsalt(HS) or 0.4% Na Cl(normal-salt,NS) diet for 3 wk,with or without tempol(T)(1 mmol/L,administered in drinking water). Mean arterial pressure(MAP),glomerularfiltration rate(GFR),and urinary sodium excretion(UVNa) were measured. We evaluated angiotensin Ⅱ(Ang Ⅱ),angiotensin 1-7(Ang 1-7),angiotensin converting enzyme 2(ACE2),mas receptor(Mas R),angiotensin type 1 receptor(AT1R) and angiotensin type 2 receptor(AT2R) in renal tissues by immunohistochemistry.RESULTS The intake of high sodium produced a slight but significant increase in MAP and differentially regulated components of the renal renin-angiotensin system(RAS). This included an increase in Ang Ⅱ and AT1 R,and decrease in ACE-2 staining intensity using immunohistochemistry. Antioxidant supplementation with tempol increased natriuresis and GFR,prevented changes in blood pressure and reversed the imbalance of renal RAS components. This includes a decrease in Ang Ⅱ and AT1 R,as increase in AT2,ACE2,Ang(1-7) and Mas R staining intensity using immunohistochemistry. In addition,the natriuretic effects of tempol were observed in NS-T group,which showed an increased staining intensity of AT2,ACE2,Ang(1-7) and Mas R.CONCLUSION These findings suggest that a high salt diet leads to changes in the homeostasis and balance between opposing components of the renal RAS in hypertension to favour an increase in Ang Ⅱ. Chronic antioxidant supplementation can modulate the balance between the natriuretic and antinatriuretic components of the renal RAS.展开更多
The Stewart approach-the application of basic physicalchemical principles of aqueous solutions to blood-is an appealing method for analyzing acid-base disorders. These principles mainly dictate that p H is determined ...The Stewart approach-the application of basic physicalchemical principles of aqueous solutions to blood-is an appealing method for analyzing acid-base disorders. These principles mainly dictate that p H is determined by three independent variables, which change primarily and independently of one other. In blood plasma in vivo these variables are:(1) the PCO2;(2) the strong ion difference(SID)-the difference between the sums of all the strong(i.e., fully dissociated, chemically nonreacting) cations and all the strong anions; and(3) the nonvolatile weak acids(Atot). Accordingly, the p H and the bicarbonate levels(dependent variables) are only altered when one or more of the independent variables change. Moreover, the source of H+ is the dissociation of water to maintain electroneutrality when the independent variables are modified. The basic principles of the Stewart approach in blood, however, have been challenged in different ways. First, the presumed independent variables are actually interdependent as occurs in situations such as:(1) the Hamburger effect(a chloride shift when CO2 is added to venous blood from the tissues);(2) the loss of Donnan equilibrium(a chloride shift from the interstitium to the intravascular compartment to balance the decrease of Atot secondary to capillary leak; and(3) the compensatory response to a primary disturbance in either independent variable. Second, the concept of water dissociation in response to changes in SID is controversial and lacks experimental evidence. In addition, the Stewart approach is not better than the conventional method for understanding acid-base disorders such as hyperchloremic metabolic acidosis secondary to a chloride-rich-fluid load. Finally, several attempts were performed to demonstrate the clinical superiority of the Stewart approach. These studies, however, have severe methodological drawbacks. In contrast, the largest study on this issue indicated the interchangeability of the Stewart and conventional methods. Although the introduction of the Stewart approach was a new insight into acid-base physiology, the method has not significantly improved our ability to understand, diagnose, and treat acid-base alterations in critically ill patients.展开更多
Objectives: to evaluate and compare serum adiponectin levels in different phenotypes of polycystic ovary syndrome (PCOS) and to investigate their correlation with endocrine and metabolic parameters. Material and metho...Objectives: to evaluate and compare serum adiponectin levels in different phenotypes of polycystic ovary syndrome (PCOS) and to investigate their correlation with endocrine and metabolic parameters. Material and methods: we studied 5 groups of patients: A (n = 20): H (hyperandrogenism) + O (oligoanovulation) + P (polycystic ovary) [classic phenotype];B (n = 17): H + O [classic phenotype but normal ovaries];C (n = 15): H + P [Ovulatory phenotype];D (n = 17): O + P [Normoandrogenic phenotype];and E (n = 16) control group. Body mass index, waist circumference, waist/hip ratio, blood pressure and hirsutism were evaluated. Serum concentrations of adiponectin, insulin, Creactive protein, SHBG, androgens and lipids were measured. Oral glucose tolerance test was performed. Results: there were no differences between the groups in terms of age and BMI. Total cholesterol, LDL-C and triglyceride levels were higher in phenotype A than in C (P P = 0.03). HOMA-IR, insulin and glucose/insulin ratio were significantly higher in phenotypes A and D vs C and E (P P P < 0.05). Conclusions: adiponectin serum concentrations vary according to the phenotypic expression of PCOS. Our results suggest that adiponectin could be used as a biochemical marker to identify phenotypes at increased metabolic risk.展开更多
Exposure to noise of high intensities(> 80 dB) is considered a stressful event and might produce both auditory and extra-auditory damage,including different central nervous system(CNS) injuries.Within the CNS,the h...Exposure to noise of high intensities(> 80 dB) is considered a stressful event and might produce both auditory and extra-auditory damage,including different central nervous system(CNS) injuries.Within the CNS,the hippocampus(HC),a structure related to several cognitive functions,has shown to be particularly susceptible to the effects of noise.展开更多
基金Supported by Grant #TB 56 from the University of Buenos Aires,Argentina
文摘AIM: To study the blood-brain barrier integrity, brain edema,animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication.METHODS: Adults male Wistar rats were divided into four groups. Group I: sham operation; II: Prehepatic portal hypertension, produced by partial portal vein ligation; III:Acetaminophen intoxication and IV: Prehepatic portal hypertension plus acetaminophen. Acetaminophen was administered to produce acute hepatic injury. Portal pressure, liver serum enzymes and ammonia plasma levels were determined. Brain cortex water content was registered and trypan blue was utilized to study blood brain barrier integrity. Reflexes and behavioral tests were recorded.RESULTS: Portal hypertension was significantly elevated in groups II and IV. Liver enzymes and ammonia plasma levels were increased in groups II, III and IV. Prehepatic portal hypertension (group II), acetaminophen intoxication (group III) and both (group IV) had changes in the blood brain-barrier integrity (trypan blue) and hyperammonemia. Cortical edema was present in rats with acute hepatic injury in groups III and IV. Behavioral test (rota rod) was altered in group IV.CONCLUSION: These results suggest the possibility of another pathway for cortical edema production because blood brain barrier was altered (vasogenic) and hyperammonemia was registered (cytotoxic). Group IV, with behavioral altered test, can be considered as a model for study at an early stage of portal-systemic encephalopathy.
基金Supported by A grant from the Universidad de Buenos Aires(UBACYT 20020130200105BA)
文摘AIM To determine the effect of tempol in normal rats fed high salt on arterial pressure and the balance between antagonist components of the renal renin-angiotensin system.METHODS Sprague-Dawley rats were fed with 8% Na Cl highsalt(HS) or 0.4% Na Cl(normal-salt,NS) diet for 3 wk,with or without tempol(T)(1 mmol/L,administered in drinking water). Mean arterial pressure(MAP),glomerularfiltration rate(GFR),and urinary sodium excretion(UVNa) were measured. We evaluated angiotensin Ⅱ(Ang Ⅱ),angiotensin 1-7(Ang 1-7),angiotensin converting enzyme 2(ACE2),mas receptor(Mas R),angiotensin type 1 receptor(AT1R) and angiotensin type 2 receptor(AT2R) in renal tissues by immunohistochemistry.RESULTS The intake of high sodium produced a slight but significant increase in MAP and differentially regulated components of the renal renin-angiotensin system(RAS). This included an increase in Ang Ⅱ and AT1 R,and decrease in ACE-2 staining intensity using immunohistochemistry. Antioxidant supplementation with tempol increased natriuresis and GFR,prevented changes in blood pressure and reversed the imbalance of renal RAS components. This includes a decrease in Ang Ⅱ and AT1 R,as increase in AT2,ACE2,Ang(1-7) and Mas R staining intensity using immunohistochemistry. In addition,the natriuretic effects of tempol were observed in NS-T group,which showed an increased staining intensity of AT2,ACE2,Ang(1-7) and Mas R.CONCLUSION These findings suggest that a high salt diet leads to changes in the homeostasis and balance between opposing components of the renal RAS in hypertension to favour an increase in Ang Ⅱ. Chronic antioxidant supplementation can modulate the balance between the natriuretic and antinatriuretic components of the renal RAS.
文摘The Stewart approach-the application of basic physicalchemical principles of aqueous solutions to blood-is an appealing method for analyzing acid-base disorders. These principles mainly dictate that p H is determined by three independent variables, which change primarily and independently of one other. In blood plasma in vivo these variables are:(1) the PCO2;(2) the strong ion difference(SID)-the difference between the sums of all the strong(i.e., fully dissociated, chemically nonreacting) cations and all the strong anions; and(3) the nonvolatile weak acids(Atot). Accordingly, the p H and the bicarbonate levels(dependent variables) are only altered when one or more of the independent variables change. Moreover, the source of H+ is the dissociation of water to maintain electroneutrality when the independent variables are modified. The basic principles of the Stewart approach in blood, however, have been challenged in different ways. First, the presumed independent variables are actually interdependent as occurs in situations such as:(1) the Hamburger effect(a chloride shift when CO2 is added to venous blood from the tissues);(2) the loss of Donnan equilibrium(a chloride shift from the interstitium to the intravascular compartment to balance the decrease of Atot secondary to capillary leak; and(3) the compensatory response to a primary disturbance in either independent variable. Second, the concept of water dissociation in response to changes in SID is controversial and lacks experimental evidence. In addition, the Stewart approach is not better than the conventional method for understanding acid-base disorders such as hyperchloremic metabolic acidosis secondary to a chloride-rich-fluid load. Finally, several attempts were performed to demonstrate the clinical superiority of the Stewart approach. These studies, however, have severe methodological drawbacks. In contrast, the largest study on this issue indicated the interchangeability of the Stewart and conventional methods. Although the introduction of the Stewart approach was a new insight into acid-base physiology, the method has not significantly improved our ability to understand, diagnose, and treat acid-base alterations in critically ill patients.
文摘Objectives: to evaluate and compare serum adiponectin levels in different phenotypes of polycystic ovary syndrome (PCOS) and to investigate their correlation with endocrine and metabolic parameters. Material and methods: we studied 5 groups of patients: A (n = 20): H (hyperandrogenism) + O (oligoanovulation) + P (polycystic ovary) [classic phenotype];B (n = 17): H + O [classic phenotype but normal ovaries];C (n = 15): H + P [Ovulatory phenotype];D (n = 17): O + P [Normoandrogenic phenotype];and E (n = 16) control group. Body mass index, waist circumference, waist/hip ratio, blood pressure and hirsutism were evaluated. Serum concentrations of adiponectin, insulin, Creactive protein, SHBG, androgens and lipids were measured. Oral glucose tolerance test was performed. Results: there were no differences between the groups in terms of age and BMI. Total cholesterol, LDL-C and triglyceride levels were higher in phenotype A than in C (P P = 0.03). HOMA-IR, insulin and glucose/insulin ratio were significantly higher in phenotypes A and D vs C and E (P P P < 0.05). Conclusions: adiponectin serum concentrations vary according to the phenotypic expression of PCOS. Our results suggest that adiponectin could be used as a biochemical marker to identify phenotypes at increased metabolic risk.
基金supported by the Universidad de Buenos Aires (20020160100005BA and 20020190100222BA)(to LRG)。
文摘Exposure to noise of high intensities(> 80 dB) is considered a stressful event and might produce both auditory and extra-auditory damage,including different central nervous system(CNS) injuries.Within the CNS,the hippocampus(HC),a structure related to several cognitive functions,has shown to be particularly susceptible to the effects of noise.
