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At least 289 records · Page 16Linked to original sources
PubMed1997

Precipitation of overt encephalopathy in the portacaval shunted rat: towards the development of an adequate model of chronic portal systemic encephalopathy.

OBJECTIVE: To assess the feasibility of developing a model of overt portal-systemic encephalopathy (PSE) in rats with a surgically constructed portacaval anastomosis (PCA). DESIGN: The ability of increasing the load of nitrogenous substances in the gastrointestinal tract and/or further decreasing hepatocellular function to induce overt encephalopathy in rats with a PCA was determined. METHODS: The load of nitrogenous substances in the gastrointestinal tract was increased by feeding a pure horse-meat diet or by gavaging with blood. Partial hepatectomy and the induction of cirrhosis were used to decrease hepatocellular function further. The severity of encephalopathy was assessed using a neurobehavioural scale. RESULTS: Overt encephalopathy was not induced in rats by a PCA alone, by a PCA plus a horse-meat diet, by a PCA plus induction of cirrhosis, or by a PCA plus a 50% hepatectomy. Predominantly mild, but overt, encephalopathy was induced in rats with a PCA alone by gavaging with blood and a higher incidence of more severe overt encephalopathy was induced in rats with a PCA combined with either cirrhosis or partial hepatectomy by gavaging with blood. Although these models of PSE were associated in some instances with plasma ammonia concentrations about 25 times higher than normal, no seizures were observed. CONCLUSION: A syndrome that resembles overt PSE in humans can be induced in the rat with a PCA by further reducing hepatocellular function and also gavaging with blood. Although the rat with a PCA has been. extensively used as a model in studies relating to the pathogenesis of PSE, a syndrome resembling overt PSE in humans cannot readily be induced in rats with a PCA.

Ammonia↗
PubMed2003

Resection of hepatocellular carcinoma in a patient with congenital anomaly of the portal system.

Hepatic resection in a patient with an anomalous portal vein system is presented. A 53-year-old man was referred to our hospital for hepatic resection. Preoperative computed tomography (CT) and angiography demonstrated that the umbilical portion of the portal vein gave off major branches to the right anterior segment, and the hepatic tumor was located on the dorsal side of one of the right anterior portal branches near the umbilical portion. Partial hepatic resection was performed using the indocyanine green staining technique under operative echo guidance. Limited hepatic resection was indicated due to the patient's poor hepatic reserve function. His postoperative course was uneventful. This case emphasizes the importance of delineating the hepatic vascular anatomy before and during operation, especially in the case of an anomalous portal vein system.

Carcinoma, Hepatocellular↗
PubMed2006

Surgery versus transjugular intrahepatic portal systemic shunt in the treatment of severe variceal bleeding.

The management of patients who have portal hypertension has changed dramatically over the last 2 decades. Pharmacologic therapy benefits the patient by reducing the risk for an initial bleed, improving the management of an acute bleed, and in reducing the risk for a rebleed. Endoscopic management has improved progressively along with endoscopic technology. For those 20% of patients that continues to have persistent high-risks varices or rebleed through first-line therapy, decompression does remain an option. The three options to decompression are liver transplant, a surgical shunt, or a transjugular intrahepatic portal systemic shunt (TIPS). This article focuses on the relative roles of these options with a particular emphasis on the current available data comparing surgical shunt with TIPS.

Esophageal and Gastric Varices↗
PubMed1997

The effect of the renal portal system on pharmacokinetic parameters in the red-eared slider (Trachemys scripta elegans).

The premise that drugs not be injected into the caudal body of reptiles because they will be carried by the renal portal system to the kidneys, where they may be nephrotoxic or rapidly excreted, was tested by comparing the pharmacokinetics of gentamicin (excreted via glomerular filtration in mammals) and carbenicillin (excreted partly via renal tubular secretion in mammals) following injection into the forelimb or hindlimb of red-eared sliders (Trachemys scripta elegans). Ten sliders received intramuscular gentamicin (10 mg/kg) in a forelimb (n = 5) or a hindlimb (n = 5), and plasma levels of the drug were assayed over time. Following drug clearance, the experiment was repeated with the site of injection reversed so that each animal acted as its own control. Another 10 sliders were similarly treated, using intramuscular carbenicillin (200 mg/kg). Injection site of gentamicin had no effect on any pharmacokinetic parameter (time to maximum plasma concentration, maximum plasma concentration, half-life, area under the curve, clearance, and volume of distribution). However, the area under the curve of plasma carbenicillin concentration vs. time was significantly lower following hindlimb injection, in comparison with forelimb injection, at 1, 4, and 8 hr, which may reflect reduced bioavailability of the drug, as would be expected with renal portal perfusion and tubular excretion on first pass through the kidney. This effect on carbenicillin likely is not clinically important because plasma levels remained above recommended minimum inhibitory concentrations. Because blood draining the caudal body of reptiles passes through the kidneys or the liver before reaching the central circulation, the effect on the pharmacokinetics of a drug injected in that region will vary with its renal or hepatic extraction rate. Generally, this effect is unlikely to be significant.

Animals↗
PubMed1977

[Immediate and late results of 171 therapeutic portal systemic by pass operations (author's transl)].

The authors reports the results of 171 cases of portal systemic by pass operations out of a total of 200 cases operated on between 1968 and 1974. These 171 patients all presented with a syndrome of portal hypertension with oesophageal varices and all had previously bled. Their age lay in 70 p. cent of cases between 40 and 60 years and the cause of hypertension was in 96 p. cent of cases an intra-hepatic block. 41 p. cent were included in the risk group A according to Child's classification, 51 p. cent in Group B and 8 p. cent in Group C. The routine operation was side-to-side portacaval anastomosis (75 p. cent). The operative mortality was 5.2 p. cent in all with 1 p. cent in cases with risk A, and 15 p. cent in cases with risk C. The fall in portal pressure was on average 15 cm of water, i.e. 41 p. cent of the initial pressure. The overall survival after 5 years was 65 p. cent, 70 p. cent for risk A and 26 p. cent for risk C. In 69 p. cent of cases the cause of death was liver failure. Encephalopathy, studied in 76 patients over an average period of 3 years, occurred in 39 p. cent of cases, and in 13 p. cent of the latter it was serious. In the 12 p. cent of survivors, we noted recurrent hemorrhage, but in only 2.5 p cent of cases did the bleeding definitely come from oesophageal varices. In the light of these results, the authors judge positively the surgical treatment of portal hypertension.

Esophageal and Gastric Varices↗
PubMedDate not supplied

Resection of metastatic liver cancer in a patient with an anomalous intrahepatic portal system: a case report.

Resection of metastatic liver cancer in a patient with an anomalous intrahepatic portal system is presented. A 67-year-old man was referred to our hospital with a liver tumor. Percutaneous transhepatic portography demonstrated that the right anterior branch of the portal vein rose from the left portal vein with agenesis of the umbilical portion. Cholangiography disclosed obstruction of the right posterior segmental bile duct by the tumor. Barium enema demonstrated a Borrmann type II cancer in the sigmoid colon. Right hepatic lobectomy and high anterior resection of the colon were performed, and postoperative histologic examination confirmed that the liver tumor was metastatic adenocarcinoma of the colon. The ligamentum teres arose from the right anterior portal vein and separated the left medial segment from the right anterior portal segment of the liver. These anomalies led to the performance of right lobectomy instead of trisegmentectomy and the patient died 10 months later of hepatic recurrence. This case emphasizes the importance of delineating the hepatic vascular anatomy before liver resection and illustrates one of the pitfalls related to portal venous anomalies.

Adenocarcinoma↗
PubMedDate not supplied

[The portal system and hepatic artery in children with biliary atresia. 1: Ultrasound and simple duplex ultrasound parameters].

In 37 children with extrahepatic biliary atresia between 12 days in 9 years of age we performed 72 duplexsonographic examinations of the portal system and the hepatic artery. In the control group we investigated 61 healthy children. All investigations were performed with computer sonography (Acuson 128) with a 3.5 MHz and 5 MHz-Transducer. We described changes of sonographic parameters such as hepatic structure, liver and splenic size. In 14 children with extrahepatic biliary atresia hepatofugal collaterals were visible. Specially in patients with collaterals we found changes of vessel diameters. The maximal flow velocity of the portal vein was significantly decreased in patients with extrahepatic biliary atresia.

Biliary Atresia↗
PubMed1991

Increased cerebrospinal fluid lactate reflects deterioration of neurological status in experimental portal-systemic encephalopathy.

Increased brain and CSF lactate have been described in human and experimental portal-systemic encephalopathy (PSE). Using a recently described cisterna magna catheter technique, CSF lactate was measured in relation to deterioration of neurological status in portacaval shunted rats administered ammonium acetate to precipitate severe PSE. Loss of righting reflex (precoma stage of PSE) was accompanied by 2-3 fold increased CSF lactate and onset of coma by 4-fold increases of lactate (p less than 0.001 compared to either sodium acetate treated portacaval shunted rats or sham-operated controls administered ammonium acetate). The most likely explanation for increased CSF lactate is ammonia-induced inhibition of malate-aspartate shuttle and/or inhibition of tricarboxylic acid cycle flux in brain. Similar mechanisms could be involved in the pathogenesis of PSE in patients with chronic liver disease.

Animals↗
PubMed1996

Acute myocardial infarction after selective portal-systemic shunt.

A case of myocardial infarction following a distal splenorenal shunt, a selective portal-systemic shunt, in a cirrhotic patient is reported. The post-operative cardiac morbidity was probably related to the hyperdynamic cardiovascular state associated with liver cirrhosis and the increase in intramyocardial tension upon formation of the distal splenorenal shunt.

Aged↗
PubMed1990

[MRI of the normal portal system: the artefacts. Apropos of 45 cases].

The protal system of 45 normal patients have been retrospectively studied on spin echo MRI sequences (interleaved cuts): multiple artifacts have been evaluated and 24% of them were visualized at the portal system level. Thus, partial volume effect responsible for almost 25% of the artifacts is not always easily seen on a single sequence. Respiratory and aortic artifacts can deteriorate the visualization of the vascular lumen but cannot be confused with a thrombosis. Well-known artifacts, as slice entry phenomenon and even echo rephasing, represent more than 60% of the artifacts: they are readily recognized when they are typical and indicate flowing blood. On the contrary, an other artifact, representing less than 5% of the total and seen at the level of the left portal vein, simulates a thrombus, on T2 weighed images. We conclude that the frequency and polymorphism of the artifacts are limiting factors of MRI value in the diagnosis of portal vein thrombosis.

Adult↗
PubMed1992

Blood flow in portal systems with special reference to the rat pituitary gland.

Regional pituitary blood flow has been studied in adult female Fischer 344 rats by [14C]iodoantipyrine autoradiography. A general mathematical solution has been derived to allow the calculation of blood flow in the second compartment of a portal system and the proportion of blood "shunted" through the first compartment without exposure to tissue uptake from a knowledge of (a) the volume ratios of the two compartments, (b) the tissue tracer uptakes of the two compartments, and (c) the arterial tracer concentration with respect to time of a freely diffusible tracer. Significant diffusion limitation and/or arteriovenous shunting has been demonstrated in the neurohypophysis, suggesting that the majority of incoming blood is "shunted" unchanged to the adenohypophysis. The mean value of the shunt is 89% (range of 84-93%) for the median eminence and lies between 72% (range of 52-82%) and 73% (range of 59-81%) for the posterior pituitary. Neurohypophysial flow rates of 1.20 (range of 0.99-1.55) ml g-1 min-1 for the median eminence and 1.68 (range of 0.83-3.53) ml g-1 min-1 for the posterior pituitary were measured. These values represent "tissue-available" (nonshunted) flow; estimated mean total (shunted plus nonshunted) neurohypophysial flow rates were 11.7 (range of 9.5-17.5) ml g-1 min-1 for the median eminence and 6.1 (range of 3.1-8.9) ml g-1 min-1 (minimum) for the posterior pituitary. Adenohypophysial blood flow is heterogeneous. In the long portal territory, the flow rate was 1.18 (range of 0.95-1.75) ml g-1 min-1 but short portal territory flow calculation is complicated by an unquantifiable nonportal venous drainage; using the natural limits of zero and 100% gives a minimum adenohypophysial flow rate of 1.42 (range of 0.76-2.07) ml g-1 min-1 and a maximum value of 1.97 (range of 1.03-2.82) ml g-1 min-1.

Algorithms↗
PubMed1985

A technique for the insertion of an implantable portal system for the long-term epidural administration of opioids in the treatment of cancer pain.

The feasibility of using a subcutaneously implanted portal system attached to a conventional 16-gauge epidural catheter has been evaluated in 50 patients with sever pain associated with cancer. This technique allowed for the percutaneous epidural administration of morphine at 8-12-hourly intervals for pain control. The mean duration of implantation was 12 weeks and the longest period a portal remained in situ was 36 weeks. Five portals had to be removed for various reasons. The injection system has blocked on eight occasions due to catheter blockage (six times) and portal blockage (two occasions). These patients have continued to obtain excellent analgesia when either catheter or portal were replaced. In a cadaver, 300 injections were simulated using either 22-gauge Huber point needles or disposable needles (25 gauge) and the injectate examined by both light and scanning electron microscopy. Both needle types resulted in particulate contamination which was greater with the recommended Huber point needles.

Analgesia↗
PubMed1986

Portal-systemic encephalopathy. Influence of shunt surgery and relations to serum amino acids.

Fifty patients with liver cirrhosis, portal hypertension, and a history of bleeding oesophageal varices underwent 15 different cognitive psychometric tests to evaluate the presence of subclinical portal-systemic encephalopathy. None of the patients were clinically encephalopathic. The patients were compared with 50 healthy control subjects. Twenty-three patients showed definite signs of encephalopathy in the psychometric tests, 17 were normal, and 10 were borderline cases. The most pronounced abnormalities were seen in tests reflecting logic inductive capacity, visual spatial performance, cognitive flexibility, perceptual speed, spatial perceptive ability, and psychomotor performance. Tests reflecting word memory were less affected. Serum liver function tests did not differ between patients with deranged and normal brain functions. The serum isoleucine concentration was, however, significantly lower in the encephalopathic patients. The psychometric test results did not differ between patients with alcoholic and nonalcoholic liver cirrhosis, and no change was noted 2 years after shunt surgery.

Amino Acids↗
PubMed1992

Portal-systemic shunting and the disruption of circadian locomotor activity in the rat.

To determine if the extent of portal-systemic shunting (PSS) influences the disruption of circadian function in chronic liver disease, locomotor activity was examined in two rat models with varying degrees of PSS, i.e., portal vein ligation (PVL) and end-to-side portacaval anastomosis (PCA). Animals were housed in individual activity cages under conditions of 12 hour light/12 hour darkness (weeks 0-3), then under conditions of constant dim light (weeks 4-7). Cages were equipped with running wheels connected to a continuous recorder, and daily tracings of running activity were recorded for 7 weeks. Computer analysis of wheel revolutions per hour with a chi 2 periodogram was used to calculate Qp, a measure of the amplitude of a circadian rhythm. The degree of PSS was measured by means of radioactive microspheres injected into the ileocolic vein and spleen. PVL rats were found to have PSS from the splenic and mesenteric territories of 88% and 27%, respectively; circadian periodicity was maintained in all PVL rats. PCA rats had complete shunting (greater than 99%) and showed a range of disrupted circadian rhythms from blunting of the amplitude to complete absence of the locomotor activity rhythm. This spectrum of disorganization occurred in spite of similar degrees of liver atrophy and weight gain. Whereas PCA in rats markedly disturbs the circadian rhythm of locomotor activity, animals with considerably less PSS from PVL exhibit normal behavior. The extent of PSS could be a variable affecting the expression of circadian rhythms in liver disease.

Animals↗
PubMed1997

Schistosoma mansoni: relocation of parasites to lungs from hepatic portal system in rodents.

The prevalence and development of adult worms in the lungs of mice and gerbils infected with Schistosoma mansoni was investigated. All infected BALB/c mice harbored the schistosomes in their lungs at 10-12 weeks post-infection, showing the distinct relocation of adult worms to the lungs, from the hepatic portal system. The male and female flukes from lungs of BALB/c mice were significantly smaller than those from livers. The percentage of gravid females in lungs was considerably lower than that in the livers. The number of eggs recovered from lungs of BALB/c mice and gerbils having lung female worms, however, was higher than that from animals without lung females, indicating egg deposition of lung females. The number of eggs detected in the brains correlated well with the number of eggs from the lungs in BALB/c and ICR mice. Out of 119 infected gerbils at 8 weeks post-infection, only two animals had egg-emboli in the brain vessels, although many eggs embolized in the lungs of those animals. These data suggest that transfer of worms to the lungs from livers involves reduction of worm recovery from the portal circulation, and also pulmonary pathology of the disease.

Animals↗
PubMed2000

Intrahepatic portal-hepatic venous anastomosis: a portal-systemic shunt with neurological repercussions.

Intrahepatic shunts are rarely diagnosed as a cause of neurocognitive abnormality. A complaint of fatigue led to the diagnosis of a right portal vein-hepatic vein aneurysmal communication in a 23-yr-old, otherwise healthy woman. Neuropsychological testing, imaging, and MR spectroscopy revealed changes similar to those described in patients with cirrhosis and subclinical hepatic encephalopathy. T1-weighted MRI showed a hyperintense globus pallidus, a feature seen in subjects with and without portal-encephalopathy. Portal-systemic shunting in the absence of parenchymal liver disease reproduces neurological features described in cirrhosis.

Adult↗