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1.
Braz J Med Biol Res ; 51(12): e7526, 2018 Nov 14.
Article in English | MEDLINE | ID: mdl-30462770

ABSTRACT

It has been previously demonstrated that the hemodynamic effect induced by angiotensin II (AII) in the liver was completely abolished by losartan while glucose release was partially affected by losartan. Angiotensin II type 1 (AT1) and adrenergic (∝1- and ß-) receptors (AR) belong to the G-proteins superfamily, which signaling promote glycogen breakdown and glucose release. Interactive relationship between AR and AT1-R was shown after blockade of these receptors with specific antagonists. The isolated perfused rat liver was used to study hemodynamic and metabolic responses induced by AII and adrenaline (Adr) in the presence of AT1 (losartan) and ∝1-AR and ß-AR antagonists (prazosin and propranolol). All antagonists diminished the hemodynamic response induced by Adr. Losartan abolished hemodynamic response induced by AII, and AR antagonists had no effect when used alone. When combined, the antagonists caused a decrease in the hemodynamic response. The metabolic response induced by Adr was mainly mediated by ∝1-AR. A significant decrease in the hemodynamic response induced by Adr caused by losartan confirmed the participation of AT1-R. The metabolic response induced by AII was impaired by propranolol, indicating the participation of ß-AR. When both ARs were blocked, the hemodynamic and metabolic responses were impaired in a cumulative effect. These results suggested that both ARs might be responsible for AII effects. This possible cross-talk between ß-AR and AT1-R signaling in the hepatocytes has yet to be investigated and should be considered in the design of specific drugs.


Subject(s)
Glucose/metabolism , Hypertension, Portal/metabolism , Liver/metabolism , Receptor, Angiotensin, Type 1/physiology , Receptors, Adrenergic, alpha/physiology , Receptors, Adrenergic, beta/physiology , Adrenergic beta-Antagonists/pharmacology , Angiotensin II Type 1 Receptor Blockers/pharmacology , Angiotensin Receptor Antagonists/pharmacology , Animals , Hemodynamics/drug effects , Hemodynamics/physiology , Liver/drug effects , Losartan/pharmacology , Male , Prazosin/pharmacology , Propranolol/pharmacology , Rats, Wistar , Receptor, Angiotensin, Type 1/drug effects , Receptors, Adrenergic, alpha/drug effects , Receptors, Adrenergic, beta/drug effects , Time Factors
2.
Braz. j. med. biol. res ; 51(12): e7526, 2018. graf
Article in English | LILACS | ID: biblio-974255

ABSTRACT

It has been previously demonstrated that the hemodynamic effect induced by angiotensin II (AII) in the liver was completely abolished by losartan while glucose release was partially affected by losartan. Angiotensin II type 1 (AT1) and adrenergic (∝1- and β-) receptors (AR) belong to the G-proteins superfamily, which signaling promote glycogen breakdown and glucose release. Interactive relationship between AR and AT1-R was shown after blockade of these receptors with specific antagonists. The isolated perfused rat liver was used to study hemodynamic and metabolic responses induced by AII and adrenaline (Adr) in the presence of AT1 (losartan) and ∝1-AR and β-AR antagonists (prazosin and propranolol). All antagonists diminished the hemodynamic response induced by Adr. Losartan abolished hemodynamic response induced by AII, and AR antagonists had no effect when used alone. When combined, the antagonists caused a decrease in the hemodynamic response. The metabolic response induced by Adr was mainly mediated by ∝1-AR. A significant decrease in the hemodynamic response induced by Adr caused by losartan confirmed the participation of AT1-R. The metabolic response induced by AII was impaired by propranolol, indicating the participation of β-AR. When both ARs were blocked, the hemodynamic and metabolic responses were impaired in a cumulative effect. These results suggested that both ARs might be responsible for AII effects. This possible cross-talk between β-AR and AT1-R signaling in the hepatocytes has yet to be investigated and should be considered in the design of specific drugs.


Subject(s)
Animals , Male , Receptors, Adrenergic, alpha/physiology , Receptors, Adrenergic, beta/physiology , Receptor, Angiotensin, Type 1/physiology , Glucose/metabolism , Hypertension, Portal/metabolism , Liver/metabolism , Propranolol/pharmacology , Time Factors , Prazosin/pharmacology , Receptors, Adrenergic, alpha/drug effects , Receptors, Adrenergic, beta/drug effects , Rats, Wistar , Adrenergic beta-Antagonists/pharmacology , Losartan/pharmacology , Receptor, Angiotensin, Type 1/drug effects , Angiotensin II Type 1 Receptor Blockers/pharmacology , Angiotensin Receptor Antagonists/pharmacology , Hemodynamics/drug effects , Hemodynamics/physiology , Liver/drug effects
3.
Int J Lab Hematol ; 31(1): 69-73, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19143871

ABSTRACT

Schistosomiasis mansoni is a non-cirrhotic liver disease. In cirrhosis patients with portal hypertension, a decreased number of reticulated platelets associated with increased thrombopoietin serum levels were reported. We previously reported a 120/nl platelet cutoff level as a marker of clinically significant portal hypertension in schistosomiasis patients. To evaluate reticulated platelet counts and thrombopoietin serum levels (TPO) in schistosomiasis patients and correlate them with portal hypertension markers. Thirty-three schistosomiasis patients without co-morbidities were endoscopically classified as those with (n = 19) or without (n = 14) clinically significant portal hypertension. Flow cytometric determination of reticulated platelets was performed using CD41 antibody and thiazol orange. Ultrasonographic examinations were performed according to the Niamey protocol. TPO and hyaluronic acid serum levels were determined in duplicate using ELISA methods. The platelet number of 120/nl discriminates the two groups with 100% accuracy and 100% positive and negative predictive values, and correlates with spleen length and portal and splenic vein diameters. Differences in reticulated platelets and hyaluronic acid serum levels between both groups were significant (P = 0.025 and 0.012, respectively), but thrombopoietin serum levels were not (P = 0.769). Schistosomiasis patients with portal hypertension have increased reticulated platelets associated with normal TPO serum levels.


Subject(s)
Blood Platelets/cytology , Schistosomiasis/blood , Thrombopoietin/blood , Blood Platelets/metabolism , Flow Cytometry , Humans , Hyaluronic Acid/blood , Reference Standards , Schistosomiasis/diagnostic imaging , Ultrasonography
4.
Braz J Med Biol Res ; 40(3): 343-8, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17334531

ABSTRACT

Animal studies and premarketing clinical trials have revealed hepatotoxicity of statins, primarily minor elevations in serum alanine aminotransferase levels. The combined chronic use of medicines and eventual ethanol abuse are common and may present a synergistic action regarding liver injury. Our objective was to study the effect of the chronic use of atorvastatin associated with acute ethanol administration on the liver in a rat model. One group of rats was treated daily for 5 days a week for 2 months with 0.8 mg/kg atorvastatin by gavage. At the end of the treatment the livers were perfused with 72 mM ethanol for 60 min. Control groups (at least 4 animals in each group) consisted of a group of 2-month-old male Wistar EPM-1 rats exposed to 10% ethanol (v/v) ad libitum replacing water for 2 months, followed by perfusion of the liver with 61 nM atorvastatin for 60 min, and a group of animals without chronic ethanol treatment whose livers were perfused with atorvastatin and/or ethanol. The combination of atorvastatin with ethanol did not increase the release of injury marker enzymes (alanine aminotransferase, aspartate aminotransferase, and lactic dehydrogenase) from the liver and no change in liver function markers (bromosulfophthalein clearance, and oxygen consumption) was observed. Our results suggest that the combination of atorvastatin with ethanol is not more hepatotoxic than the separate use of each substance.


Subject(s)
Ethanol/toxicity , Heptanoic Acids/toxicity , Liver/drug effects , Pyrroles/toxicity , Alanine Transaminase/blood , Animals , Aspartate Aminotransferases/blood , Atorvastatin , Biomarkers/blood , Drug Synergism , Ethanol/administration & dosage , Heptanoic Acids/administration & dosage , L-Lactate Dehydrogenase/blood , Liver/enzymology , Liver/pathology , Liver Function Tests , Male , Oxygen Consumption , Perfusion , Pyrroles/administration & dosage , Rats , Rats, Wistar , Sulfobromophthalein/pharmacokinetics
5.
Braz. j. med. biol. res ; 40(3): 343-348, Mar. 2007. tab
Article in English | LILACS | ID: lil-441767

ABSTRACT

Animal studies and premarketing clinical trials have revealed hepatotoxicity of statins, primarily minor elevations in serum alanine aminotransferase levels. The combined chronic use of medicines and eventual ethanol abuse are common and may present a synergistic action regarding liver injury. Our objective was to study the effect of the chronic use of atorvastatin associated with acute ethanol administration on the liver in a rat model. One group of rats was treated daily for 5 days a week for 2 months with 0.8 mg/kg atorvastatin by gavage. At the end of the treatment the livers were perfused with 72 mM ethanol for 60 min. Control groups (at least 4 animals in each group) consisted of a group of 2-month-old male Wistar EPM-1 rats exposed to 10 percent ethanol (v/v) ad libitum replacing water for 2 months, followed by perfusion of the liver with 61 nM atorvastatin for 60 min, and a group of animals without chronic ethanol treatment whose livers were perfused with atorvastatin and/or ethanol. The combination of atorvastatin with ethanol did not increase the release of injury marker enzymes (alanine aminotransferase, aspartate aminotransferase, and lactic dehydrogenase) from the liver and no change in liver function markers (bromosulfophthalein clearance, and oxygen consumption) was observed. Our results suggest that the combination of atorvastatin with ethanol is not more hepatotoxic than the separate use of each substance.


Subject(s)
Animals , Male , Rats , Ethanol/toxicity , Heptanoic Acids/toxicity , Liver/drug effects , Pyrroles/toxicity , Alanine Transaminase/blood , Aspartate Aminotransferases/blood , Biomarkers/blood , Drug Synergism , Ethanol/administration & dosage , Heptanoic Acids/administration & dosage , L-Lactate Dehydrogenase/blood , Liver Function Tests , Liver/enzymology , Liver/pathology , Oxygen Consumption , Perfusion , Pyrroles/administration & dosage , Rats, Wistar , Sulfobromophthalein/pharmacokinetics
7.
J Gastroenterol Hepatol ; 16(1): 41-5, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11206315

ABSTRACT

BACKGROUND: We have shown that the portal hypertensive response to bradykinin in normal rats is mediated by B2 receptors. METHODS: By using isolated and exsanguinated rat liver perfusion, we studied the portal hypertensive response to bradykinin or des-Arg9-bradykinin (B1 agonist) in inflamed or cirrhotic rat livers. Livers were perfused with bovine serum albumin Krebs-Henseleit buffer (pH 7.4; 37 degrees C) at a constant flow rate, in the absence or presence of des-Arg9[Leu8]-bradykinin or HOE 140 (B1 and B2 receptor antagonists, respectively). Bradykinin (140 nmol) or des-Arg9-bradykinin was injected as a bolus via the afferent route to the liver. RESULTS: Basal perfusion pressure in liver-cirrhotic rats was higher than in normal rats. In normal, inflamed, or liver-cirrhotic rats, the presence of the B1 antagonist did not change the portal hypertensive response to bradykinin, while the B2 antagonist abolished this response. A 140-nmol dose of des-Arg9-bradykinin did not change the perfusion pressure; 700 nmol of this B1 agonist produced an insignificant perfusion pressure increase. The perfusion pressure increase induced by bradykinin in cirrhotic livers was lower than in normal livers. CONCLUSIONS: The portal hypertensive response to bradykinin in inflamed or cirrhotic rat livers is mediated by B2 receptors, but not B1 receptors, and there is a contracting hyporeactivity to bradykinin in cirrhotic rat livers.


Subject(s)
Bradykinin/pharmacology , Hypertension, Portal/drug therapy , Kallidin/analogs & derivatives , Kallidin/pharmacology , Liver Cirrhosis/metabolism , Receptors, Bradykinin/metabolism , Analysis of Variance , Animals , Carbon Tetrachloride , Inflammation , Liver Cirrhosis/chemically induced , Liver Cirrhosis/pathology , Male , Rats , Rats, Wistar , Turpentine
8.
Dig Dis Sci ; 45(10): 1964-70, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11117568

ABSTRACT

Sufferers of schistosomiasis mansoni can evolve a clinical form of the disease associated with portal hypertension. To differentiate this form, routine clinical tests and biological indices were evaluated. In all, 54 HBsAg- and HCV-negative patients were studied, 42 with schistosomiasis and 12 normal volunteers. Using clinical criteria, ultrasonography, and endoscopy, the schistosomiasis patients were classified into two groups: mild chronic form (MS, N = 14) and chronic form associated with portal hypertension (PH, N = 28). The laboratory parameters of the MS group did not differ from the controls. The PH group differed from the others in prothrombin index, thrombocytemia, gamma-glutamyltransferase, serum alpha2-macroglobulin, and the calculated indices. ROC plot cutoff levels verified that isolated thrombocytemia was the most efficient marker for discrimination of the PH and MS forms. Thrombocytemia of 130 x 10(9) platelets/liter discriminated the groups with an 86% accuracy when all patients were analyzed and 96% when only schistosomiasis patients who did not consume alcohol were included.


Subject(s)
Hypertension, Portal/diagnosis , Schistosomiasis mansoni/diagnosis , Thrombocytosis/diagnosis , Adult , Aged , Brazil , Female , Humans , Liver Function Tests , Male , Middle Aged , Platelet Count , Predictive Value of Tests , Prognosis
9.
Life Sci ; 67(5): 509-20, 2000 Jun 23.
Article in English | MEDLINE | ID: mdl-10993116

ABSTRACT

Bradykinin (BK) is a potent hepato-portal hypertensive agent although it is efficiently inactivated by the liver. The organ converts angiotensin I to AII, but at a much slower rate than it inactivates BK. We had previously identified EC 3.4.24.15 as an hepatic bradykinin inactivating endopeptidase that hydrolyzes BK at the F5-F6 bond. The aim of this study was to determine the relative importance of BIE, as compared to other kininases, in normal, cirrhotic or inflamed rat livers, as well as in samples of human liver. Using specific substrates and inhibitors we showed that: 1) purified BIE preparation hydrolyzed BK and a BK analogue (BK-Q) with similar efficacy; BK-Q was functionally active since it caused an increase in hepato-portal pressure, as did BK itself. 2) BK degradation in rat serum was performed by ACE since BIE and prolylendopeptidase (PEP) activities were negligible. 3) normal rat liver homogenate contained a large amount of BIE activity which was eliminated by a specific EC 3.4.24.15 inhibitor; ACE and PEP activities were negligible. 4) There was no difference (p>0.05) in BIE activity in the liver homogenates from rats with normal, inflamed or cirrhotic livers. 5) BIE activity was efficiently removed from livers (normal, inflamed or cirrhotic) that were perfused with TritonX-100.6) Human liver had an similar enzymatic pattern although ACE activity was detected. We concluded that in normal, inflamed or cirrhotic rat livers, as well as in the human liver, the bradykinin inactivating endopeptidase (EC 3.4.24.15), and not ACE, is the major hepatic kininase.


Subject(s)
Endopeptidases/metabolism , Liver/enzymology , Metalloendopeptidases/metabolism , Amino Acid Sequence , Animals , Blood Pressure/drug effects , Bradykinin/analogs & derivatives , Bradykinin/pharmacology , Enzyme Inhibitors/pharmacology , Humans , Metalloendopeptidases/antagonists & inhibitors , Peptidyl-Dipeptidase A/metabolism , Rats , Rats, Wistar , Substrate Specificity , alpha-Macroglobulins/metabolism
10.
Braz J Med Biol Res ; 33(1): 119-25, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10625883

ABSTRACT

We have shown that tissue-type plasminogen activator (tPA) and plasma kallikrein share a common pathway for liver clearance and that the hepatic clearance rate of plasma kallikrein increases during the acute-phase (AP) response. We now report the clearance of tPA from the circulation and by the isolated, exsanguinated and in situ perfused rat liver during the AP response (48-h ex-turpentine treatment). For the sake of comparison, the hepatic clearance of a tissue kallikrein and thrombin was also studied. We verified that, in vivo, the clearance of 125I-tPA from the circulation of turpentine-treated rats (2.2 +/- 0.2 ml/min, N = 7) decreases significantly (P = 0.016) when compared to normal rats (3.2 +/- 0.3 ml/min, N = 6). The AP response does not modify the tissue distribution of administered 125I-tPA and the liver accounts for most of the 125I-tPA (>80%) cleared from the circulation. The clearance rate of tPA by the isolated and perfused liver of turpentine-treated rats (15.5 +/- 1.3 microg/min, N = 4) was slower (P = 0.003) than the clearance rate by the liver of normal rats (22. 5 +/- 0.7 microg/min, N = 10). After the inflammatory stimulus and additional Kupffer cell ablation (GdCl3 treatment), tPA was cleared by the perfused liver at 16.2 +/- 2.4 microg/min (N = 5), suggesting that Kupffer cells have a minor influence on the hepatic tPA clearance during the AP response. In contrast, hepatic clearance rates of thrombin and pancreatic kallikrein were not altered during the AP response. These results contribute to explaining why the thrombolytic efficacy of tPA does not correlate with the dose administered.


Subject(s)
Acute-Phase Reaction/enzymology , Liver/metabolism , Thrombin/pharmacokinetics , Tissue Kallikreins/pharmacokinetics , Tissue Plasminogen Activator/metabolism , Animals , Kupffer Cells/metabolism , Male , Metabolic Clearance Rate , Perfusion , Rats , Rats, Wistar , Tissue Plasminogen Activator/blood
11.
Braz. j. med. biol. res ; 33(1): 119-25, Jan. 2000. tab, graf
Article in English | LILACS | ID: lil-252265

ABSTRACT

We have shown that tissue-type plasminogen activator (tPA) and plasma kallikrein share a common pathway for liver clearance and that the hepatic clearance rate of plasma kallikrein increases during the acute-phase (AP) response. We now report the clearance of tPA from the circulation and by the isolated, exsanguinated and in situ perfused rat liver during the AP response (48-h ex-turpentine treatment). For the sake of comparison, the hepatic clearance of a tissue kallikrein and thrombin was also studied. We verified that, in vivo, the clearance of 125I-tPA from the circulation of turpentine-treated rats (2.2 + or - 0.2 ml/min, N = 7) decreases significantly (P = 0.016) when compared to normal rats (3.2 + or - 0.3 ml/min, N = 6). The AP response does not modify the tissue distribution of administered 125I-tPA and the liver accounts for most of the 125I-tPA (>80 percent) cleared from the circulation. The clearance rate of tPA by the isolated and perfused liver of turpentine-treated rats (15.5 + or - 1.3 µg/min, N = 4) was slower (P = 0.003) than the clearance rate by the liver of normal rats (22.5 + or - 0.7 µg/min, N = 10). After the inflammatory stimulus and additional Kupffer cell ablation (GdCl3 treatment), tPA was cleared by the perfused liver at 16.2 + or - 2.4 µg/min (N = 5), suggesting that Kupffer cells have a minor influence on the hepatic tPA clearance during the AP response. In contrast, hepatic clearance rates of thrombin and pancreatic kallikrein were not altered during the AP response. These results contribute to explaining why the thrombolytic efficacy of tPA does not correlate with the dose administered


Subject(s)
Animals , Male , Rats , Acute-Phase Reaction/enzymology , Liver/enzymology , Thrombin/pharmacokinetics , Tissue Kallikreins/blood , Tissue Kallikreins/pharmacokinetics , Tissue Plasminogen Activator/metabolism , Kupffer Cells/metabolism , Metabolic Clearance Rate , Perfusion , Rats, Wistar , Tissue Plasminogen Activator/blood
12.
Arq Gastroenterol ; 37(2): 93-101, 2000.
Article in Portuguese | MEDLINE | ID: mdl-11144021

ABSTRACT

The main causes of pancreatic inflammation worldwide are biliary lithiasis and alcoholism. However, 10 to 30% of patients have been considered to have "idiopathic" acute pancreatitis. Recently, some studies showed that a significant rate of the so called idiopathic pancreatitis are caused by microlithiasis and/or biliary sludge, identified by the presence of cholesterol monohidrate and/or calcium bilirubinate microcrystals in the biliary sediment. In the present study, the analysis of microcrystals from bile obtained during endoscopic retrograde cholangiopancreatography was done in patients with pancreatitis (idiopathic, biliary or alcoholic--20 in each group). Patients with idiopathic pancreatitis and microcrystals in the bile underwent cholecystectomy whenever possible. Those who refused or were inapt to surgery underwent endoscopic sphincterotomy or received continuous therapy with ursodeoxycholic acid. Patients with idiopathic pancreatitis without biliary crystals did not receive any specific treatment. The prevalence of biliary microcrystals in patients with idiopathic pancreatitis (75%) and biliary pancreatitis (90%) was significantly higher than in those with alcoholic pancreatitis (15%). In the identification of the etiology of biliary pancreatitis, the presence of microcrystals had a sensitivity of 90%, specificity of 85%, positive predictive value of 85.7%, negative predictive value of 89.4% and accuracy of 87.5%. In the patients with recurrent idiopathic pancreatitis, with biliary crystals, there was an statistically significant reduction in the number of pancreatitis episodes after specific treatment. In the follow-up of this group during 23.3 +/- 4.8 months, recurrence of pancreatitis occurred only in patients with "persistent biliary factor" (choledocholithiasis and/or persistence of cholesterol monohidrate). All patients with idiopathic pancreatitis who underwent cholecystectomy had chronic cholecystitis. Moreover, cholelithiasis was present in one case. In the ultrassonographic follow-up of the patients with idiopathic acute pancreatitis with microcrystals in the bile, cholelithiasis was detected in one case. In the subgroup of five patients with idiopathic pancreatitis without biliary microcrystals recurrence occurred in one case. Ultrassonographic study during follow-up did not reveal biliary stones in any of these patients. We concluded that the detection of biliary microcrystals in "idiopathic" pancreatitis suggested an underlying biliary etiology, even if occult. What's more, early specific therapeutic procedure (cholecystectomy, endoscopic sphincterotomy or ursodeoxycholic acid) in patients with recurrent idiopathic pancreatitis with microcrystals in the bile reduced significantly the recurrence during the follow-up. Finally, acute pancreatitis (specially recurrent) should not be called idiopathic before the microscopic analysis of the bile, aiming to detect or exclude the presence of microcrystals.


Subject(s)
Gallstones/complications , Pancreatitis/etiology , Acute Disease , Adolescent , Adult , Aged , Aged, 80 and over , Bile/chemistry , Case-Control Studies , Cholecystectomy , Female , Follow-Up Studies , Gallstones/chemistry , Gallstones/therapy , Humans , Male , Middle Aged , Pancreatitis/surgery , Predictive Value of Tests , Probability , Prospective Studies , Recurrence
13.
Rev Assoc Med Bras (1992) ; 45(3): 206-16, 1999.
Article in Portuguese | MEDLINE | ID: mdl-10513051

ABSTRACT

PURPOSE: To review some aspects of the hepatic phylogeny and ontogeny, the hepatic microvascular system, and the modulation of the tonus on this vascular system by different vasoactive substances. METHOD: Text books and articles from MEDLINE-indexed journals were consulted. RESULTS: Fifty-two articles, that were published between 1949 and 1997, were selected. They provided us with information concerning hepatic phylogeny and ontogeny, the hepatic microvascular system, and the modulation of the tonus in this vascular system. CONCLUSION: The architecture of the hepatic microvascular system, a unique and complex vascular system, is well suited to the functions of the organ. Different factors, including endothelial vasoactive substances, participate in the modulation of the vascular resistance through the liver adequating the liver perfusion to the homeostatic needs. The liver is eminently a maintainer of internal stability.


Subject(s)
Biological Factors/physiology , Liver/blood supply , Liver/physiology , Vasodilation/physiology , Angiotensins/physiology , Bradykinin/physiology , Endothelins/physiology , Epoprostenol/physiology , Homeostasis/physiology , Humans , Microcirculation , Nitric Oxide/physiology , Phylogeny
14.
Rev. Assoc. Med. Bras. (1992) ; 45(3): 206-16, jul.-set. 1999. ilus
Article in Portuguese | LILACS | ID: lil-241198

ABSTRACT

Objetivo. Revisão da filogênese e ontogênese hepáticas, do sistema microvascular hepático e da modulação do tônus deste sistema vascular por diferentes substâncias vasoativas. Método. Levantamento de artigos por meio do sistema Medline e consulta a livros-texto. Resultado. Foram selecionados 52 trabalhos publicados entre 1949, dos quais retiramos as informações a respeito de filogênese e ontogênese hepáticas, sistema microvascular hepático e mecanismos de controle do tônus vascular hepático. Conclusão. O fígado possui sistema vascular altamente especializado na promoção de mecanismos de troca entre hepatócitos e sangue. Diferentes fatores atuam continuamente sobre estruturas contrácteis deste sistema vascular adequando a perfusão do tecido hepático às necessidades homeostáticas de cada momento. O fígado é órgão eminentemente mantenedor do meio interno.


Subject(s)
Humans , Liver/blood supply , Liver/physiology , Vasodilator Agents , Angiotensin II/physiology , Bradykinin/physiology , Endothelins/physiology , Epoprostenol/physiology , Homeostasis/physiology , Microcirculation , Nitric Oxide/physiology , Phylogeny
15.
Rev Assoc Med Bras (1992) ; 45(1): 19-23, 1999.
Article in Portuguese | MEDLINE | ID: mdl-10436589

ABSTRACT

BACKGROUND: The liver inactivates considerable amounts of bradykinin; the main liver kinin-inactivating enzyme (BIE, bradykinin inactivating endopeptidase) hydrolyses specifically the Phe5-Ser6 bond of the nonapeptide and it has been characterized as the oligoendopeptidase E.C.3.4.24.15. When orthotopic liver transplantation is performed there is a correlation between the increase of amino acid concentration in the preservation fluid (as a consequence of proteolysis) and graft dysfunction. AIM: Verify if BIE is released from livers stored ex vivo. METHOD: Wistar rats (180-220 g) livers were exsanguinated and after removal were preserved in Braun Collins fluid or Krebs solution at 4 degrees C. Aliquots were collected from the preservation fluid at 0, 4, 8, 24 h, for ALT, AST, LDH and BIE assays. The fluorimetric activity of BIE was assayed upon Abz-RPPGFSPFRQ-EDDnp (synthetic BK analogue) and its presence was confirmed by immunoblotting, revealed with specific antibody anti-E.C.3.4.24.15. RESULTS: The release of ALT, AST, LDH and BIE is significant between 8-24 h. In the 24 h aliquots the four enzymes concentration increased in the Braun Collins fluid 8, 7, 19 and 10 respectively, and in the Krebs solution 21, 17, 27, 21 respectively, when compared to the zero time aliquot activities. The ratio ALT/LDH was always < 1. CONCLUSION: There is BIE release during ex vivo liver storage; this information may be useful as an indicator of the graft preservation condition; a decrease of the liver kinin-inactivating capability could affect the graft vascular reactivity.


Subject(s)
Bradykinin/antagonists & inhibitors , Endopeptidases/metabolism , Endopeptidases/pharmacology , Liver/enzymology , Animals , Organ Preservation , Rats , Rats, Wistar
16.
Rev. Assoc. Med. Bras. (1992) ; 45(1): 19-23, jan.-mar. 1999. ilus
Article in Portuguese | LILACS | ID: lil-233204

ABSTRACT

Objetivo - Ofígado inativa quantidades consideráveis de bradicinina; a principal enzima hepática cinino-inativadora (BIE, bradykinin inativating endopeptidase) hidrolisa especificamente a ligaçao Phe-Ser do nonapeptídio e foi caracterizada como sendo a oligoendopeptidase EC 3.4. 24.15. No transplante ortotópico de fígado existe correlaçao entre aumento da concentraçao de aminoácidos no líquido de preservaçao (conseqUência de proteólise) e falência do enxerto. O objetivo deste trabalho é verificar se ocorre liberaçao da BIE de fígados preservados ex-vivo no líquido Braun-Collins ou em soluçao de Krebs-Henseleit bicarbonato (Krebs). Método. Fígado de ratos Wistar (180-220g) foram exsangüinados e a pós remoçao foram preservados em líquido Braun Collins ou em soluçao Krebs, a 4 graus Celsius. Foram retiradas alíquotas do líquido de preservaçao nos tempos 0, 4, 8 e 24 horas, para dosagem de ALT, AST, DHL e BIE. A atividade fluorimétrica da BIE foi ensaiada com o substrato Abz-RPPGFSPFRQ-EDDnp (análogo sintético da bradicinina) e sua presença confirmada por immunoblotting, revelado com anticorpo específico anti-EC 3.4.24.15. Resultados. A liberaçao de ALT, AST, DHL e BIE é significativa no período 8-24 hs. Nas alíquotas de 24 hs, em relaçao ao tempo zero, a concentraçao das quatro enzimas aumentou, respectivamente, no líquido Braun Collins, 8, 7, 19 e 10 vezes e, na soluçao de Krebs, 21, 17, 27 e 21 vezes; a relaçao ALT/DHL foi sempre inferior a um. Conclusao. Ocorre liberaçao de BIE durante a preservaçao ex-vivo do fígado, o que poderá servir como indicaçao da condiçao de preservaçao do enxerto; diminuiçao da capacidade cinino-inativadora do fígado poderá afetar sua reatividade vascular.


Subject(s)
Animals , Rats , Bradykinin/antagonists & inhibitors , Endopeptidases/metabolism , Endopeptidases/pharmacology , Liver/enzymology , Immunoblotting , Organ Preservation , Rats, Wistar
17.
Liver ; 18(6): 371-7, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9869390

ABSTRACT

AIMS/BACKGROUND: The liver clears circulating plasma-kallikrein through a receptor-mediated endocytosis process: an initial fast phase is followed by a slow exponential phase. METHODS: To determine whether the clearance rate of plasma-kallikrein is affected during liver regeneration, we perfused isolated rat livers with rat plasma-kallikrein (rPK) at 0, 1, 2, 3 and 7 days after partial hepatectomy or sham operation. RESULTS: Liver regeneration was followed by the expression of the proliferating-cell nuclear antigen (PCNA) labeling index. The serum concentration of alpha2-macroglobulin, an acute phase protein in rats, was measured. At day 1, the fast phase of rPK clearance rate increased in hepatectomized rats when compared with day 0 (4.9+/-0.4 and 3.7+/-0.4 mU/g liver min, p<0.05). However, at day 2, the rPK fast phase clearance rate dropped significantly (2.6+/-0.2, p<0.05), when compared with day 1. No difference was found among the sham groups at different days of hepatectomy. These changes seem to be independent of the acute phase reaction. The regenerative liver weight increased continuously during the observation period. PCNA expression increased significantly after hepatectomy, with maximal PCNA-labeling indices at days 1 and 2, declining thereafter. CONCLUSION: The rPK fast phase clearance rate changes during liver regeneration, with a zenith occurring when PCNA labeling index is maximal (day 1) and a nadir occurring at the mitotic phase (day 2).


Subject(s)
Hepatectomy , Kallikreins/pharmacokinetics , Liver Regeneration/physiology , Liver/metabolism , Animals , Kallikreins/administration & dosage , Male , Metabolic Clearance Rate , Organ Size , Perfusion , Proliferating Cell Nuclear Antigen/metabolism , Rats , Rats, Sprague-Dawley , alpha-Macroglobulins/analysis
18.
J Hepatol ; 29(2): 233-40, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9722204

ABSTRACT

BACKGROUND/AIMS: Liver dysfunction is said to occur only late in the course of schistosomiasis. As albumin levels tend to be normal, the observed prolonged prothrombin time is thought to arise from subclinical consumption coagulopathy. The aim of this study was to further evaluate this matter by studying the role of Schistosoma mansoni and liver function in the genesis of the compromised haemostasis tests in chronic "pure" schistosomiasis patients. METHODS: Twenty-five adults with chronic "pure" schistosomiasis were selected: 12 with the hepatointestinal form (group 2) and 13 with the compensated hepatosplenic form (group 3), as well as 10 matched control individuals (group 1). Alcoholism, viral hepatitis B and C, malnutrition (BMI<20 kg/m2), use of anticoagulant or anti-aggregant drugs and chronic diseases apart from schistosomiasis were carefully excluded. All patients were submitted to abdominal ultrasound and upper digestive endoscopy. Blood samples were used for routine hepatic tests and for transthyretin, prothrombin, antithrombin and protein C antigen determinations by immunodiffusion. Laboratory markers of coagulation activation (prothrombin fragment1+2(F1+2), serine esterases-antithrombin complexes (ATM) and plasminogen activator, tissue type activity (t-PA) were also assayed by ELISA and photometric determination, respectively. RESULTS: Decreased plasma levels of transthyretin (p<0.001), protein C (p:0.006), prothrombin (p:0.022) and antithrombin (p:0.008) contrasted with normal albuminaemia (p:0.094), F1+2 (p:0.061) and ATM (p:0.714) plasma levels in group 3 patients; t-PA activity (p:0.001) on the other hand, were increased in this group. CONCLUSIONS: These results suggest impairment of liver clearance and protein synthesis capacity rather than consumption coagulopathy. They also indicate that changes in liver function are not a late event in the course of schistosomiasis.


Subject(s)
Liver Diseases/epidemiology , Liver Function Tests , Schistosomiasis mansoni/complications , Adult , Alanine Transaminase/blood , Alcohol Drinking , Alkaline Phosphatase/blood , Animals , Aspartate Aminotransferases/blood , Blood Coagulation Tests , Chronic Disease , Humans , Liver Diseases/etiology , Liver Diseases/parasitology , Middle Aged , Parasite Egg Count , Patient Selection , Risk Factors , Schistosoma mansoni/isolation & purification , Schistosomiasis mansoni/physiopathology
19.
Rev. Assoc. Med. Bras. (1992) ; 43(3): 189-94, jul.-set. 1997. tab
Article in Portuguese | LILACS | ID: lil-201482

ABSTRACT

A deficiência de antitrombina III (ATIII) é observada na hepatopatia grave e pode ser decorrente da reduçäo de síntese ou de consumo aumentado, o que poderia ser compensado com o uso de concentrado de ATIII. OBJETIVO. Avaliar a eficiência da administraçäo de uma dose fixa de concentrado de ATIII, em pacientes com hepatopatia descompensada com distúrbio de hemostasia. CASUISTICA E MÉTODO. Foram avaliados seis pacientes, com idade média de 44 anos, variando de 14 a 63 anos, portadores de cirrose (quatro de etiologia alcoólica, um viral e um doença de Wilson), com alteraçäo de pelo menos dois dos parâmetros da hemostasia (TP> 1,40, TTPA> 1,25, fibrinogênio < 1,5g/L, plaquetas < 80.000/mm3). A média do nível de albumina foi de 2,6g/dL (1,9 a 3,8g/dL). O concentrado de ATIII (Kybernin) foi administrado na dose de 50U/kg, em dias alternados. Foi colhido sangue antes da primeira infusäo, 4 horas após e, depois, diariamente, antes da infusäo do dia, para medida da ATIII plasmática (amidolítico). Nenhum paciente recebeu hemoderivados. RESULTADOS. As médias da dosagem de ATIII foram: inicial = 35,8 por cento, 4 horas = 56,2 por cento*, 2 dias = 48,7 por cento*, 4 dias = 45,7 por cento* e 8 dias = 42,3 por cento*. Após a infusäo houve elevaçäo significante dos níveis de ATIII (* = p < 0,02, teste de Friedman), que se manteve até o 4§ dia. Näo houve alteraçäo dos demais parâmetros de coagulaçäo. CONCLUSÕES. O uso de concentrado de ATIII na dose utilizada é suficiente para elevar os níveis desse inibidor na hepatopatia; entretanto, com essa dose näo se obteve normalizaçäo de seus níveis. Esses dados sugerem que doses mais elevadas devem ser usadas em pacientes com hepatopatias graves, que apresentam näo apenas reduçäo de síntese, mas aumento de consumo dos fatores da coagulaçäo e de seus inibidores.


Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Antithrombin III/therapeutic use , Blood Coagulation Disorders/therapy , Liver Cirrhosis , Serine Proteinase Inhibitors/therapeutic use , Antithrombin III , Fibrinogen , Hepatitis, Viral, Human/complications , Hepatolenticular Degeneration/complications , Liver Cirrhosis/etiology , Liver Diseases, Alcoholic/complications , Partial Thromboplastin Time , Platelet Count , Prothrombin Time
20.
Rev Assoc Med Bras (1992) ; 43(3): 189-94, 1997.
Article in Portuguese | MEDLINE | ID: mdl-9497544

ABSTRACT

BACKGROUND: Patients with severe hepatic failure present acquired deficiency of antithrombin III (ATIII) owing to reduced synthesis associated with intravascular activation of blood coagulation, which may be corrected by ATIII infusion. OBJECTIVE: The aim of this uncontrolled trial was to verify the effect of a standard dose of ATIII concentrate (Kybernin), that is, 50 U/kg of body weight per day, every 2 days, on ATIII levels in patients with severe hepatic failure and hemostatic imbalance. PATIENTS AND METHODS: Six cirrhotic patients were studied: mean age of 44 years (14 to 63 years), who presented at least 2 abnormal coagulation tests (PT > 1.40, APTT > 1.25, Fibrinogen < 1.5 g/dL, Platelet count < 80,000/mm3). Mean serum albumin was 2.6 g/dL (1.9 to 3.8 g/dL). Blood was drawn before infusion, 4 h after the first infusion, and just before the next infusion. ATIII levels were measured by amidolytic method. RESULTS: Mean ATIII levels were: initial = 35.8%, 4th h = 56.2%*, 2nd d = 48.7%*, 4th d = 45.7%*, and 8th d = 42.3%. ATIII levels increased significantly after infusion of this standard dose in all patients, although they have not been fully corrected (Friedman test, * p < 0.02), which has been sustained till the 4th day. There was no improvement on the clinical outcome. CONCLUSIONS: These findings suggest that doses of ATIII concentrate higher than 50 U/kg/infusion must be administered to patients with severe hepatic failure, to guarantee normal levels of the inhibitor, in order to verify its influence on the hemostatic mechanism.


Subject(s)
Antithrombin III/therapeutic use , Blood Coagulation Disorders/drug therapy , Liver Cirrhosis/complications , Serine Proteinase Inhibitors/therapeutic use , Adolescent , Adult , Blood Coagulation Disorders/complications , Female , Hepatitis, Viral, Human/complications , Hepatolenticular Degeneration/complications , Humans , Liver Diseases, Alcoholic/complications , Male , Middle Aged , Platelet Count , Prothrombin Time
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