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Biomedical subjects

M A Aller

Publications and source records attributed to M A Aller.

At least 37 records · Page 2Linked to original sources
PubMed1994

Behaviour of nucleolar organizer regions in the different Wistar rat liver lobes.

The area and number of silver-nucleolar organizer regions (Ag-NORs) in the hepatic lobes were determined in 3 male Wistar rats. There was a statistically significant increase in the percentage of Ag-NORs per nucleus in the right lateral and caudate lobe in relation to the left lateral and middle lobes. The area and number of Ag-NORs are greater in the caudate and right lateral lobes in relation to the left lateral and middle lobes. Since the Ag-NOR is a parameter which indicates hepatocytic protein synthesis, the different activity which corresponds to each lobe of the rat's liver makes it possible to assume that there is a functional heterogeneity which should be considered in the study of the hepatic regeneration according to the type of partial hepatectomy carried out.

Animals↗
PubMed1994

Behavior of nucleolar organizer regions in the different hepatic lobes after end-to-side portacaval shunt in the rat.

Protein synthesis activity in the hepatic lobes in control and end-to-side portacaval shunt rats was studied by assaying one of the argyrophilic components (Ag-NOR) of the hepatocytic nucleolus. The differences found in the area and number of Ag-NOR for each nucleus and in the percentage of Ag-NOR area to nucleus area in each hepatic lobe in control rats as well as in the end-to-side portacaval shunt rats suggest that there are interlobular differences in the control rats related to this parameter that are indicative of protein synthesis and cell proliferation. Furthermore, the changes that occur in these parameters after the deprivation of portal flow produced by an end-to-side portacaval shunt make it possible to hypothesize on the existence of a hepatic lobular functional heterogeneity in the rat liver.

Animals↗
PubMed1994

Hemorrhagic gastroesophageal ulceration by pulmonary infection in extrahepatic cholestatic pigs.

We developed a biliary and pulmonary microbiologic study in 22 Large-White pigs that underwent bile-duct ligation in order to demonstrate that sepsis has a biliary and pulmonary origin which may be involved in the gatroesophageal pathology. All the pigs died at 18.2 +/- 8.9 days of the post-operative period. The cause of death was hemorrhagic ulceration of the gastroesophageal region in 36.3% (n = 8) of the animals that also presented multiple bilateral miliary lung abscesses. High infestation rates with intestinal germs were found in the bile and lung. In conclusion, the experimental model of extrahepatic cholestasis in the Large-White pig could be useful for the study of etiopathogenic mechanisms by which the pulmonary infection produces a hemorrhagic gastroesophageal ulceration considered as stress ulcer.

Animals↗
PubMed1993

A model of cholestasis in the rat, using a microsurgical technique.

An experimental model of extrahepatic cholestasis in the rat, using a microsurgical technique, is described. Sixteen days postoperatively all of the animals (n = 10) were alive and had hepatomegaly, splenomegaly, jaundice, and hyperbilirubinemia. The use of this technique prevents the development of hepatic cysts and other complications inherent in the surgical techniques of cholestasis, such as hepatopneumonic abscesses.

Animals↗
PubMed1990

Heterotopic auxiliary liver transplantation with portal flow. Gradual development of the collateral circulation.

One of the causes of auxiliary liver transplantation failure is the inter-liver competition between the host liver and the graft for the hepatotrophic factors of the portal blood. We have developed an experimental model of heterotopic partial (30%) liver isotransplant using Wistar rats so as to study this competition. Splenoportography and dissection demonstrate the existence of collateral circulation. The collaterals at 90 days post-transplant (PT) consisted of veins from the portal vein to the host liver (PR), paraesophageal veins (PE) and splenorenal veins (SR). At 60 days P.T., PR and SR veins but not PE ones appeared, and at 30 days P.T., there were only PR veins. Graft atrophy at 90 days P.T. was associated with a severe degree of bile duct proliferation. The gradual development of portal hypertension causes porto-systemic collateral circulation and the graft loses the portal hepatotrophic factors. The late development of the portal hypertension and the biliary proliferation could be caused by the hepatic arterial ischemia in this experimental model. Thus, as has been described in the orthotopic liver transplantation, the heterotopic one might require a double vascularization, both portal and arterial.

Animals↗
PubMed1990

[Critical Care Surgery Unit in general and digestive system surgery].

In a 5-bed Critical Care Surgery Unit (UQCC) where surgeons are in charge of care, 126 patients admitted over 5 consecutive months were divided into 4 groups according to the treatment given: Group I (n = 49): elective gastrointestinal surgery; Group II (n = 52): emergency gastrointestinal surgery; Group III (n = 15): non-gastrointestinal surgery; Group IV (n = 10): medical treatment. The mean stay of all patients in the Surgical Critical Care Unit was 6 +/- 7.7 days and the global mortality was 7.9% (n = 10). The mean age of the patients who died was 71.5 +/- 7.3 years and 70% of the deaths corresponded to Group II. Forty percent of the patients who died had systemic candidiasis. Among the factors implicated in the mortality acute gastrointestinal pathology per se, the coexistence of chronic systemic disease and advanced age were prominent. We discuss the need for typifying the role of Surgical Critical Care Units in General and Gastrointestinal Surgery.

Adolescent↗
PubMed1989

[Immunosuppression with cyclosporin after orthoptic liver transplant in pigs].

The immunosuppressive effect of cyclosporine A (CsA) was studied in six pigs that underwent orthotopic liver transplant (OLT). The drug was administered i.v. in low doses (1.5-4 mg/Kg-1/12 h-1) and associated with wide spectrum antibiotics. The mean survival of the animals was 23.4 +/- 11.2 days. All animals had fever, jaundice and hypertrichosis, and the preoperative corporal weight remained constant. Liver abscesses by E. coli were common autopsy findings. Livers also presented biliary regeneration and cholestasis with a slight lymphocytic infiltration. OLT in pigs without immunosuppressive treatment causes and elevation in serum gamma-GTP, GOT, LDH, alkaline phosphatase and bilirubin. In the post-mortem findings, the livers did not present abscesses but evidenced intense atrophy with hepatocellular necrosis and abundant lymphocytic infiltration.

Animals↗
PubMedDate not supplied

Chronic portal hypertension in the rat by triple-portal stenosing ligation.

A surgical technique based on the development of a triple stenosing ligation is used to worsen the complications inherent to the prehepatic chronic portal hypertension. The results have been compared with those obtained in rats with a single-portal stenosing ligation. An increase (p <.05) in the body, liver, spleen, and kidney weights as well as a decrease (p <.001) in the testes weight to body weight ratio were produced in both groups of animals. In addition, the variability in the obtained weights, particularly in the liver weight, stands out. The incidence of portosystemic and portohepatic collateral circulation and of the mesenteric venous vasculopathy increases in the animals with triple-portal stenosing ligation. The new proposed technique is a valid alternative to the classic one that used single portal stenosing ligation.

Animals↗
PubMedDate not supplied

Microsurgical extrahepatic cholestasis in the rat: a long-term study.

An experimental model of microsurgical cholestasis is studied as an alternative to the most frequently used surgical techniques, based on the section of the common bile duct. This microsurgical technique consists of the resection of the extrahepatic biliary tract, that is, of the common bile duct in continuity with the bile ducts that drain the four lobes of the rat liver. At 30 days of evolution, rats with microsurgical cholestasis do not develop biliary pseudocysts or intraperitoneal hilar hepatopulmonary abscesses and show an increase (p < 0.001) in total bilirubin (9.50 +/- 1.50 mg/dL vs. 1.60 +/- 0.35 mg/dL), bile acids (225 +/- 87 micromol/L vs. 12.5 +/- 14.50 micromol/L), gamma-glutamyltranspeptidase (375 +/- 143 U/L vs. 8 +/- 11 U/L), and alkaline phosphatase (73 +/- 25 U/L vs. 23 +/- 4 U/L) levels. The histological study shows fibrosis with biliary proliferation. The microsurgical cholestasis technique is a valid alternative to other techniques and can be an adequate experimental model for the study of etiopathogenic mechanisms of obstructive jaundice and especially to study extrahepatic biliary atresia.

Animals↗