Biomedical subjects

R Mazzanti

Publications and source records attributed to R Mazzanti.

At least 19 recordsLinked to original sources

PubMed1999

Gross pathologic types of hepatocellular carcinoma in Italy.

The prevalence and independent predictors of the different macroscopic types of hepatocellular carcinoma (HCC) were assessed in 1,073 unselected patients of 14 hospitals in Italy from May 1996 to May 1997. Solitary HCC was the most common cancer type (44.6%), followed by multinodular (44.2%), diffuse (8.4%) and massive (2.8%) types. After adjustment for the influence of confounders by multiple logistic regression analysis, Child-Pugh grades B and C were found to be independent predictors of multinodular (odds ratio, OR, 2.0; 95% confidence interval (CI) = 1.5-2.6) and diffuse (OR 2.6; 95% CI = 1.6-4.4) HCC types. These findings indicate that the majority of HCC cases are not detected at a potentially treatable stage. Delayed detection of HCC is associated with a higher likelihood of the multinodular or diffuse gross pathologic type.

Carcinoma, Hepatocellular↗

PubMed1998

Characteristics of hepatocellular carcinoma in Italy.

BACKGROUND/AIMS: This study aimed to assess the main features of hepatocellular carcinoma at the time of diagnosis in Italy, particularly in relation to the presence or absence of underlying cirrhosis, hepatitis virus marker patterns, age of the subjects and alpha-foetoprotein values. METHODS: A total of 1148 patients with hepatocellular carcinoma seen at 14 Italian hospitals in the 1-year period from May 1996 to May 1997 were the subjects of this prevalence study. Both newly diagnosed cases (incident cases) and cases diagnosed before May 1996 but still attending the hospitals during the study period (prevalent cases) were included. RESULTS: We found that 71.1% of cases were positive for hepatitis C virus antibodies but negative for HBsAg; in contrast, 11.5% were negative for anti-HCV but positive for HBsAg; 5.3% were positive for both markers; and 12.1% were negative for both viruses. The mean age of detection was over 60 years, with a younger mean age in HBsAg-positive compared to anti-HCV-positive patients (59.3 years vs. 65.6 years, p<0.01). The male-to-female ratio among HBsAg-positive patients was 10.4:1, in contrast to 2.8:1 among anti-HCV-positive patients (p<0.01). The majority of cases (93.1%) had underlying cirrhosis. Cirrhotic patients were more likely to be anti-HCV positive than non-cirrhotic cases (73.2% vs 43.9%; p<0.01); conversely, absence of hepatitis virus markers was more frequently observed in the non-cirrhotic than in the cirrhotic population (40.9% vs. 10.0%; p<0.01). Overall, the alpha-foetoprotein level was altered (>20 ng/ml) in 57.9% of patients; only 18% of cases presented diagnostic (>400 ng/ml) values. Anti-HCV positivity (O.R. 2.0; CI 95%=1.3-3.1) but not HBsAg positivity (O.R. 1.0; CI 95%=0.6-1.8) was shown to be an independent predictor of the likelihood of altered alpha-foetoprotein values by multivariate analysis. CONCLUSIONS: These findings point to differences in the characteristics of the populations infected by hepatitis B and hepatitis C. Factors other than the hepatitis viruses are important in non-cirrhotic patients. A change in the relative prevalence of hepatitis virus markers among hepatocellular carcinoma cases was demonstrated, reflecting a significant change in the rate of HBV endemicity in the Italian population. Finally, the increased trend in the mortality rate from liver cancer in Italy from 4.8 per 100,000 in 1969 to 10.9 in 1994 may reflect the large cohort of subjects infected with HCV via the iatrogenic route during 1950s and 1960s when glass syringes were commonly used for medical treatment.

Adult↗

PubMed1997

Chronic viral hepatitis induced by hepatitis C but not hepatitis B virus infection correlates with increased liver angiogenesis.

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections lead to cirrhosis and increase the risk for the development of hepatocellular carcinoma (HCC). Angiogenesis is an essential step in oncogenesis and contributes to tumor progression in adult organs; however, to what extent angiogenesis occurs in the liver during chronic viral hepatitis has not been studied. Ninety-nine matched patients affected by chronic hepatitis due to either HBV or HCV were studied together with 13 controls (5 patients were affected by familial hyperbilirubinemia with normal liver histology; 6 patients with stage II primary biliary cirrhosis; and 2 patients with pseudo inflammatory tumor). Microvessel density was assessed in liver biopsies by immunostaining using two different antibodies against endothelial cell antigens, QB-END/10 and Factor VIII. In addition, the liver homogenates and sera of HCV- or HBV-positive patients and controls were tested for their capacity to stimulate the migration and proliferation of freshly isolated human endothelial cells in vitro. Evidence of angiogenesis was significantly more frequent in HCV-positive patients compared with HBV-infected subjects or controls (74% vs. 39% vs. 8%) (chi2 = 20.78; P < .0001) (HCV+ vs. HBV+ vs. controls). The degree of microvessel density was also higher in HCV- than in HBV-positive patients or controls (chi2 = 12.28; P < .005). In addition, HCV-positive sera and liver homogenates stimulated a higher migration and proliferation of human endothelial cells in vitro compared with HBV-positive or control sera and liver homogenates. These observations indicate that angiogenesis is particularly linked to HCV infection, suggesting a possible contribution to HCV-related liver oncogenesis.

Adolescent↗

PubMed1997

Respiratory mechanics in patients with tense cirrhotic ascites.

Lung volumes are decreased by tense ascites and increase after large volume paracentesis (LVP). The overall effect of ascites and LVP on the respiratory function is poorly understood. We studied eight cirrhotic patients with tense ascites before and after LVP. Inspiratory muscle force (maximal transdiaphragmatic pressure (Pdi,max), and the lowest pleural pressure (Pp1,min)) was assessed while the patients were seated. Rib cage and abdominal volume displacements, as well as pleural and gastric pressures were measured during quiet breathing while the patients were supine. Pdi,max and Ppl,min were normal and did not change after LVP (from 84.2+/-19.7 to 85.2+/-17.0 cmH2O and from 68.3+/-19.7 to 74+/-15.9 cmH2O, respectively). The abdominal contribution to the generation of tidal volume was greater than that of the rib cage (79 vs 21%), a pattern which did not change after LVP (73 and 27%). Before LVP, tidal swings both of pleural pressure (Ppl,sw) and transdiaphragmatic pressure (Pdi,sw) were large (15.3+/-4.3 and 18.5+/-3.9 cmH2O, respectively) and the load on inspiratory muscles was increased as a consequence of elevated dynamic elastance of the lung (El,dyn) (11.4+/-2.6 cmH2O x L(-1)) and ("intrinsic") positive end-expiratory pressure (PEEPi) (4.3+/-3.5 cmH2O). LVP reduced the load on the inspiratory muscles, as shown by the significant decrease in Ppl,sw (10.6+/-2.0 cmH2O), Pdi,sw (12.8+/-3.0 cmH2O), El,dyn (10.0+/-2.0 cmH2O x L(-1)) and PEEPi (1.1+/-1.3 cmH2O). The amount of fluid removed was closely related to changes in Ppl,sw and PEEPi. We conclude that the strength of the inspiratory muscles is normal or reduced in seated cirrhotic patients. In the supine position, tense ascites results in an increase in lung elastic load and development of positive end-expiratory pressure, with a consequent overload and increased activation of inspiratory muscles. Large volume paracentesis decreases overloading and activation, but does not change the strength of the inspiratory muscles.

Ascites↗

PubMed1997

Long course and prognostic factors of virus-induced cirrhosis of the liver.

OBJECTIVE: Chronic infection by hepatitis B virus (HBV) and hepatitis C virus (HCV) is now recognized as a major cause of liver cirrhosis. This study was aimed at evaluating the natural history of the disease in a large series of Italian patients with HBV- and HCV-related cirrhosis without portal hypertension at entry. METHODS: The clinical records of 405 patients (233 males, mean age 54 +/- 9 yr) with histologically proven cirrhosis (321 with HCV-related and 84 with HBV-related cirrhosis) and no clinical evidence of portal hypertension at entry were retrospectively examined to evaluate the occurrence of complications and the cumulative mortality rate during follow-up. RESULTS: Patients had a mean follow-up of 8 +/- 3 yr. The cumulative survival rate was 99.1% at 5 yr, 76.8% at 10 yr, and 49.4% at 15 yr. The age-adjusted death rate was 3.14 and 2.84 times higher than in the general Italian population in men and women, respectively. Only the bilirubin level was an independent indicator of survival. Esophageal varices, ascites, jaundice, hemorrhage, hepatic encephalopathy, and hepatocellular carcinoma significantly reduced the survival rate (major complications), whereas thrombocytopenia, diabetes, and cholelithiasis did not affect survival (minor complications). The incidence of hepatocellular carcinoma was similar in patients with either HBV- or HCV-related disease and was quite frequent, especially in males. CONCLUSIONS: This study demonstrates that the course of virus-induced liver cirrhosis is not influenced by the etiology of the disease and that the occurrence of complications significantly shortens life expectancy. The longer survival rate observed in this study is probably due to the fact that cirrhosis was here recognized by liver biopsy in the absence of clinical evidence of portal hypertension.

Bilirubin↗

PubMed1996

Conferring drug resistance by MDR1 gene transfection increases susceptibility to irradiation and lipid peroxidation in 3T3 cell line.

This study was performed to test the hypothesis that conferring multiple drug resistance reduces cell susceptibility to irradiation and iron-stimulated lipid peroxidation. Multidrug resistant (PN1A) and parental drug sensitive (PSI-2) cell lines were exposed to ADP-Fe or Ascorbate-Fe complexes at 37 degrees C and to irradiation. Lipid peroxidation was estimated by the TBA test, whereas x-ray effect was estimated by clonogenic assay. Cell glutathione-S-transferase (GST), total and Se-dependent glutathione peroxidase (GSH-Px) activities, and glutathione and vitamin E were measured. PN1A produced more peroxides than PSI-2 after exposure to iron complexes and formed fewer colonies after irradiation. Higher activities of GST and total and Se-GSH-Px were observed in PN1A. Vitamin E and total glutathione did not differ in the two cell subclones. These data show that the induction of the mdr1 phenotype by transfection of mdr1 gene in 3T3 cells increases susceptibility to irradiation and iron stimulated lipid peroxidation.

3T3 Cells↗

PubMed1996

[Viral liver cirrhosis: natural course, pathogenesis and clinical implications of the complications].

The role of hepatitis B virus (HBV) and hepatitis C virus (HCV) as a major cause of chronic liver disease is now accepted worldwide. This study was aimed at evaluating the natural history of the disease in patients with virus-induced chronic active hepatitis or cirrhosis, and the influence played by age, sex and etiology, liver function tests and by the occurrence of different complications. We retrospectively examined the clinical records of 506 inpatients: 194 were affected by chronic active hepatitis (125 males, 69 females, mean age 45 +/- 11 years, 146 HCV- and 48 HBV-related), and 312 by cirrhosis without clinical evidence of portal hypertension (178 males, 134 females, mean age 53 +/- 9 years, 249 HCV- and 63 HBV-related). The occurrence of cirrhosis in the chronic active hepatitis group was then calculated, together with the occurrence of complications and the cumulative mortality rate of established cirrhosis. During follow-up 93 patients with chronic hepatitis developed cirrhosis. The cumulative probability of developing cirrhosis in this group was 6.64% at 5 years, 56.1% at 10 years and 86.8% at 15 years. These patients were therefore included in the cirrhosis group for the final analysis, so that a total of 405 cirrhotic patients were evaluated: these patients had a cumulative survival rate of 99.1% at 5, 76.8% at 10 and 49.4% at 15 years. Comparing the age-adjusted death rate of our patients with the general Italian population, we observed that in patients with liver cirrhosis it was 3.14 and 2.84 times higher in men and women, respectively. Bilirubin was an independent indicator of survival. Several complications, such as esophageal varices, ascites, jaundice, hemorrhage, hepatic encephalopathy and hepatocellular carcinoma significantly reduced the survival rate and were indicated as major complications, while thrombocytopenia, cholelithiasis and diabetes did not affect survival and thus were called minor complications. Incidence of hepatocellular carcinoma was very high especially in males, without correlation with etiology. In conclusion, the progression of virus-induced chronic active hepatitis to cirrhosis is not influenced by sex and etiology. Similarly, the different etiology does not modify the natural history of cirrhosis while the occurrence of one or more major complications significantly shortens survival. The longer survival rate observed in patients with cirrhosis included in this study is probably due to the selective inclusion of patients with early disease and no evidence of portal hypertension.

Adult↗

PubMed1995

Susceptibility to lipid peroxidation of human hepatocellular carcinoma cell lines with different levels of multiple drug-resistant phenotype.

BACKGROUND: It has not been established whether the presence of intrinsic or acquired multiple drug-resistant (MDR) phenotype affects susceptibility to undergo iron-stimulated lipid peroxidation. EXPERIMENTAL DESIGN: To assess this point, human hepatocellular carcinoma cell lines with moderate, clinically relevant (P1) or elevated (P1(0.5)) MDR phenotype and their parental drug-sensitive (P5) cell line were exposed to ADP-Fe or ascorbate-Fe complexes and H2O2 in different experiments. Thiobarbituric acid-reactive substances (TBARS) were measured. Total cell glutathione, glutathione-S-transferase, total and selenium-dependent glutathione peroxidase activities, and cell alpha-tocopherol content were also determined. RESULTS: P5 and P1 cell lines showed similar and significant formation of TBAR after 1-hour incubation exposure to iron complexes, whereas P1(0.5) subclone did not. No accumulation of TBAR was observed during the exposure to H2O2 in the three cell lines. Among antioxidants, only alpha-tocopherol cell content was significantly higher in P1(0.5) in comparison with either P1 or P5. CONCLUSIONS: These data suggest that MDR phenotype development per se does not increase resistance to iron-related free radical attack in human hepatocellular carcinoma cell lines. Resistance to undergo lipid peroxidation is associated only to high degrees of drug resistance and appears more related to increased alpha-tocopherol cell content rather than an MDR phenotype.

Adenosine Diphosphate↗

PubMed1994

"Inapparent" hepatitis B virus infection and hepatitis C virus replication in alcoholic subjects with and without liver disease.

We evaluated hepatitis B virus DNA and hepatitis C virus RNA in sera from 110 HBsAg and IgM HBc antibody-negative heavy drinkers (50 cirrhosis, 13 chronic active hepatitis, 25 fatty liver with or without mild to moderate fibrosis, alcoholic hepatitis or both and 22 healthy alcoholic subjects) with polymerase chain reaction. Results of hepatitis C virus polymerase chain reaction were compared with those obtained with two tests (second generation recombinant immunoblot assay and enzyme-linked immunosorbent assay) used to detect hepatitis C virus antibodies. Hepatitis B virus DNA was found in three (2.7%) patients. Hepatitis C virus RNA was detected in 29 (29.8%) of the 97 subjects whose sera were well preserved for RNA extraction (42.5% cirrhosis, 83.3% chronic active hepatitis, 8% fatty liver and 0% healthy alcoholic subjects). Results obtained with second-generation recombinant immunoblot assay and enzyme-linked immunosorbent assay had a high degree of agreement with polymerase chain reaction as expected, the kappa indexes being 0.76 and 0.61, respectively. Nevertheless, five hepatitis C virus RNA-positive patients had negative recombinant immunoblot assay results, whereas all hepatitis C virus RNA-positive patients had positive or borderline enzyme-linked immunosorbent assay results. We conclude that, in Italian HBsAg-negative alcoholic patients, "inapparent" hepatitis B virus infection is rare. On the contrary, hepatitis C virus infection, as detected on hepatitis C virus polymerase chain reaction, is quite frequent, especially in patients who have cirrhosis and chronic active hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Bile acid inhibition of P-glycoprotein-mediated transport in multidrug-resistant cells and rat liver canalicular membrane vesicles.

To study the effect of bile acids on P-glycoprotein-mediated drug transport, we performed experiments using multidrug resistant cells and rat canalicular membrane vesicles. Cellular accumulation and efflux of rhodamine 123 were measured in drug-resistant cells by means of computerized quantitative image analysis and fluorescence microscopy. ATP-dependent [3H]daunomycin transport was studied by means of rapid filtration in canalicular membrane vesicles prepared from normal rats. Doxorubicin-sensitive (PSI-2) and -resistant (PN1A) 3T3 cells and human-derived hepatocellular carcinoma doxorubicin-sensitive and -resistant cells were used. Taurochenodeoxycholate and glycochenodeoxycholate, taurolithocholate and ursodeoxycholate (50 to 200 mumol/L) inhibited rhodamine 123 and [3H]daunomycin transport in multidrug-resistant cells and canalicular membrane vesicles, respectively, whereas taurocholate, taurodeoxycholate and tauroursodeoxycholate did not. Primary and secondary unconjugated bile acids had no effect. These results reveal that taurolithocholate, taurochenodeoxycholate and glycochenodeoxycholate and ursodeoxycholate inhibit P-glycoprotein-mediated drug transport function in multidrug resistant cell lines and in canalicular membrane vesicles. These results suggest possible interaction between P-glycoprotein function and bile acids in cholestasis and after treatment of patients with ursodeoxycholic or chenodeoxycholic acid.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Long-term ambulatory enterogastric reflux monitoring. Validation of a new fiberoptic technique.

A new technique for the long-term ambulatory detection of enterogastric and nonacid gastroesophageal reflux has been conceived, developed, and validated. It is based on the use of a fiberoptic sensor that utilizes the optical properties of bile. In vitro studies have shown good precision, good stability, sensitivity of 2.5 mumol/liter bilirubin concentration, as well as a useful working range of 2.5-100 mumol/liter bilirubin concentration. In vivo studies have been performed in 29 subjects. Simultaneous gastric aspirations have allowed a comparison of fiberoptic system measurements both with spectrophotometric analysis and bile acid concentrations of corresponding gastric juice samples. Linear correlations were shown between fiberoptic assessment and both spectrophotometric and bile acid concentration findings (P < 0.01). Simultaneous assessment of reflux with the fiberoptic system and cholescintigraphy has shown a 92.9% concordance as regards the presence or absence of reflux. Present results imply that the fiberoptic system is an important tool for the understanding of the clinical relevance of enterogastric and nonacid gastroesophageal reflux.

Adult↗

PubMed1993

Reflux-related gastric mucosal injury is associated with increased mucosal histamine content in humans.

BACKGROUND: Experimental studies in the dog and the rat have shown histamine involvement in reflux-related gastric mucosal injury. However, no definite demonstrations of a link between reflux-related gastric mucosal injury and mast cell mediators exist in humans. METHODS: The relationships between reflux, gastric mucosal histamine content, and gastric histology were assessed in partially gastrectomized subjects presumptively with high (11 Billroth II subjects) and low reflux levels (9 total biliary diversion subjects), respectively. Findings were compared with those in a control group consisting of 8 endoscopically and histologically proven normal subjects. RESULTS: Bile acid quantity and concentration in the gastric aspirates were significantly greater in Billroth II subjects than in total biliary diversion subjects. Significantly higher cumulative scores for foveolar hyperplasia, mucosal edema, capillary dilatation and congestion, and smooth muscle fibers in the lamina propria were found in Billroth II subjects than in total biliary diversion subjects. Mucosal histamine content as well as mast cell density and degranulation differed significantly between Billroth II and the other two groups. CONCLUSIONS: These results represent the first demonstration in humans of an association between mast cell mediators and chemical gastric mucosal injury.

Adult↗

PubMed1993

[The pathogenetic mechanisms of intrahepatic cholestasis].

The present review firstly gives some details regarding nosological approach to the cholestatic syndrome. In addition, different steps are considered, identifying 12 possible metabolic defects responsible for determining a cholestatic syndrome either in man or in experimental conditions. Eleven defects out of these 12 steps should be considered related to the structure and function of the hepatocyte, whereas the twelfth one, which comprises 3 different sub-groups, is based on a mechanical obstructive mechanism, localized exclusively into the liver parenchyma, thus resembling the other ones included in the chapter of intrahepatic cholestasis.

Bile↗

PubMed1992

Benzquinamide inhibits P-glycoprotein mediated drug efflux and potentiates anticancer agent cytotoxicity in multidrug resistant cells.

We have previously shown that efflux of cytotoxic drugs from multidrug resistant (MDR) cell lines can be quantitated at the single cell level using a sensitive fluorescence microscopy technique. Based on the structure of compounds which inhibited the efflux of Rhodamine-123 (Rho-123) using this methodology, we hypothesized that the antiemetic, antihistaminic agent benzquinamide (BZQ) would interfere with P-glycoprotein (P-gp) mediated drug transport and potentiate the effects of anticancer agents in MDR cell lines. We show that BZQ interferes with P-gp mediated drug efflux and increases drug accumulation in MDR cells using Rho-123 as a fluorescent probe. BZQ increases the cytotoxicity of chemotherapeutic agents to both human and hamster MDR cell lines in vitro. A slight increase in cytotoxicity to chemotherapeutic agents is also observed in the parental cell lines with BZQ. BZQ increases [3H]daunorubicin accumulation and inhibits the binding of [125I]iodoaryl azidoprazosin to the P-gp in MDR cells. BZQ is a new agent to increase the cytotoxic effects of anticancer agents in MDR cells and may ultimately prove useful as an adjunct in cancer chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Acute phase proteins in alcoholics with or without liver injury.

Acute phase proteins behaviour has been examined in chronic alcoholics to verify the hypothesis that chronic alcohol consumption stimulates the hepatic synthesis of acute phase proteins. Certain acute phase proteins were studied in two groups of alcoholics, one with and one without liver damage, and in a third group of healthy volunteers. The results show that the acute phase proteins were similar in the two groups of alcoholics, but differed when compared to the control group. The authors have concluded from these results, that chronic alcohol consumption causes a serum increase of: mucoproteins (p less than 0.001), alpha 1 acid glycoprotein (p less than 0.05), haptoglobin (p less than 0.05) and fibrinogen (p less than 0.02). Such increases are independent from the existence of liver damage.

Acute-Phase Proteins↗

PubMed1991

Gastric cell proliferation kinetics and bile reflux after partial gastrectomy.

Thirty-four randomized, partially gastrectomized subjects (12 with a Billroth II, 11 with a Billroth I, and 11 with a total biliary diversion reconstruction) were studied in order to assess the relationships between bile reflux, gastric histology, and cell proliferation kinetics. Bile acid quantity and concentration in the gastric aspirates progressively decreased from Billroth II to Billroth I to total biliary diversion (after which reflux was almost absent). Perianastomotic mucosa in Billroth II subjects showed the greatest degree of foveolar hyperplasia, and this decreased markedly with increasing distance from the anastomosis. Hyperplastic changes were less evident in Billroth I, and virtually absent in total biliary diversion subjects. The overall foveolar hyperplasia-like behavior of cell kinetic parameters (total pit cell number, labeled pit cell number, and labeling index) was shown. Moreover, subjects with mean bile acid concentration greater than 150 mumol/L had both a greater prevalence of foveolar hyperplasia and greater values of cell kinetic parameters than those with mean bile acid concentration less than or equal to 150 mumol/L. A superficialization of the proliferative compartment was also evident in the former group. These results show a close relationship between postgastrectomy bile reflux, foveolar hyperplasia, and cell kinetic parameters. Histologic and cell kinetic findings are probably the expression of gastric adaptation to chronic bile reflux exposure. Moreover, the type and entity of cell kinetic involvement and its relationship to foveolar hyperplasia and reflux may suggest new "tools" in post-gastrectomy surveillance and help to clarify patterns of gastric carcinogenesis.

Bile Reflux↗

PubMed1990

Structure and function of P-glycoprotein in the normal liver and intestine.

Multidrug resistance (MDR) genes encode a family of membrane glycoproteins of approximately 170 kD (P-glycoproteins). In man and mouse, the MDR 1 (mdr 1) genes confer resistance to relatively hydrophobic cationic anti-cancer drugs (i.e., vinblastin, adriamycin). Anti-cancer drug sensitivity is restored by addition of other drugs (i.e., verapamil, reserpine) which are also P-glycoprotein substrates. Transfection of MDR 1 genes produces the resistance phenotype and overexpression of P-glycoprotein. Parenchymal cells in several normal tissues express P-glycoprotein in the secretory domain of the plasma membrane (i.e., bile canaliculus of hepatocytes, brush border of proximal tubular, and small intestinal cells). Studies using plasma membrane vesicles of different sidedness derived from the bile canaliculus and small intestinal brush border permit characterization of P-glycoprotein as a unidirectional, temperature dependent, saturable, ATP-dependent transporter which is competitively inhibited by various anti-cancer drugs and other compounds. Transport studies using single cell fluorescence microscopy with image analysis confirm observations in vesicles. No natural substrate has been identified. Structural studies indicate that the requirements for substrates are molecular weight of 350 to 100, hydrophobicity, two planar rings, and a weak cationic charge. Alternative mechanisms of transport function are considered. The identity of P-glycoproteins in normal rat and human tissues has not been established. Antibody reactions suggest that they may belong to the MDR 2 or 3 class. Studies using everted gut sacs suggest that inhibition of P-glycoprotein may facilitate accumulation of anti-cancer drugs in the tissue.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1989

Hepatic lipid peroxidation and aldehyde dehydrogenase activity in alcoholic and non alcoholic liver disease.

It has been suggested that lipid peroxidation plays a role in the pathogenesis of chronic alcoholic liver disease (CALD). However, whether or not CALD differs from chronic non alcoholic liver disease (CLD) in lipid peroxidation, is still questionable. Thirty-eight patients affected by CALD and CLD who were matched for age, sex, nutrition and liver function tests (LFTs) and 17 controls (C) took part in this study. The following tests were performed: serum and liver malondialdehyde (MDA) determination by the TBA test, liver total glutathione (GSH) estimate, mitochondrial (ALDH2) and cytosolic (ALDH1) aldehyde dehydrogenase activity determinations. Patients who showed signs of malnutrition were excluded from this study. Serum and hepatic TBA-reactive substances resulted in a slight increase in chronic liver patients compared to controls but did not show any difference between CALD and CLD groups. Liver total glutathione did not show any change. Hepatic ALDH2 activity was significantly (P less than 0.01) higher in CALD than in CLD and control patients whereas ALDH1 did not show any difference. These results suggest that the increased lipid peroxidation in CALD and in CLD is probably secondary to liver damage rather than being the pathogenic factor.

Adult↗