Browsing by Author "DUARTE, I"

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    ACCURACY OF THE 1ST ENDOSCOPIC PROCEDURE IN THE DIFFERENTIAL-DIAGNOSIS OF GASTRIC-LESIONS
    (1982) LLANOS, O; GUZMAN, S; DUARTE, I
    The accuracy of endoscopy and directed biopsy in the differential diagnosis of gastric lesions was evaluated by comparing the diagnoses of 1 endoscopic procedure (endoscopy and multiple directed biopsies) with the definitive diagnoses in 333 patients. The overall endoscopic and bioptic accuracy rate for all patients amounted to 98.8%. Separate accuracy rates of endoscopy alone and biopsy were 86.5 and 94.9%, respectively. The reliability of endoscopy was similar in the diagnosis of malignant and benign lesions (86 and 89%). Endoscopic biopsy was correct in 99.1% of benign lesions and in 86% of malignancies. False negative rates were 3.9% for endoscopy and 4.0% for biopsy. False positive rate was 5.5% for endoscopy alone and 2.1% for biopsy. One endoscopic procedure is a highly reliable method in the differential diagnosis of benign and malignant gastric lesions.
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    CYTOLOGIC DETECTION OF ENDOMETRIAL CARCINOMA BY THE ENDOCYTE TECHNIQUE
    (1983) YAZIGI, R; SANCHEZ, J; DUARTE, I; VERNI, J
    Patients (97) admitted for diagnostic curettage of peri- and postmenopausal bleeding underwent cytologic evaluation by the endocyte technique to test the accuracy of the method. Six patients with endometrial carcinoma were diagnosed by curettage and in 5 of them the cytologic specimens correctly agreed with histology; the other case was an inadequate sample for cytologic diagnosis. Hyperplastic endometrium was found in 14 cases by curettage; only 3 of them were detected by cytology. This cytologic technique proved to be satisfactory in diagnosing endometrial cancer but inadequate for detection of premalignant lesions.
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    EFFECT OF COLCHICINE AND HEAT-SHOCK ON MULTIDRUG-RESISTANCE GENE AND P-GLYCOPROTEIN EXPRESSION IN RAT-LIVER
    (ELSEVIER SCIENCE BV, 1994) VOLLRATH, V; WIELANDT, AM; ACUNA, C; DUARTE, I; ANDRADE, L; CHIANALE, J
    The multidrug resistance genes encode plasma membrane glycoproteins named P-glycoproteins, that act as an ATP-dependent drug efflux pump and decrease the cytosolic concentration of chemotherapeutic agents. It has been hypothesized that in rat liver, this protein may have a physiological role as a biliary transporter of xenobiotics and endobiotics. Some human tumor cell lines turn on the human multidrug resistance gene in response to high temperature and after exposure to toxic chemicals. Accordingly, it has been proposed that the human multidrug resistance gene is a heat shock gene. We have assessed whether two environmental stresses, heat shock or acute exposure to cytotoxic drugs (colchicine, vincristine, vinblastine and daunomycin), induce changes in the expression of multidrug resistance genes in the rat. Total cellular RNA extracted from rat liver was hybridized to a labeled human multidrug resistance gene cDNA probe. Temperature upshift did not increase the steady-state of mdf mRNA levels in the tissues studied, suggesting that the mdr genes are not activated as part of a heat shock response. The mdi mRNA levels increased in rat liver as early as 3 h after a single injection of colchicine, reached a peak (500%; p<0.05) after around 24 h and returned to constitutive levels after 48 h. Changes in the relative content of mdr mRNA were not detected in kidney, adrenal gland and small bowel, suggesting that the in vivo induction of the mdr gene in the liver is a tissue-specific response. The other cytotoxic drugs that were tested did not increase the steady-state of mdr mRNA levels. Using specific PCR-generated mouse mdr cDNA probes, we found that only the mdr 2 gene is overexpressed in the liver of colchicine-treated mouse. The mdr gene induction was followed at 48-72 h by a stronger immunostaining in rat liver of its encoded product, suggesting that the newly synthesized protein was incorporated into the canalicular domain of hepatocytes. This is the first evidence of modulation of mdr expression gene in rodent liver in response to colchicine, a substrate of P-glycoprotein in multidrug resistant cells. (C) Journal of Hepatology.
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    FREQUENCY OF GALLBLADDER CANCER IN CHILE, A HIGH-RISK AREA
    (1988) NERVI, F; DUARTE, I; GOMEZ, G; RODRIGUEZ, G; DELPINO, G; FERRERIO, O; COVARRUBIAS, C; VALDIVIESO, V; TORRES, MI; URZUA, A
    We report an autopsy study of gallbladder cancer prevalence in Chile, where the risk of this disease is among the highest reported world-wide. In 14,768 autopsy protocols obtained from 3 university hospitals, 45% of women and 20% of men older than 20 years had gallstone disease (the major known risk factor for gallbladder cancer). The prevalence of gallbladder cancer in Chileans was compared to that found in a Swedish-Czechoslovakian autopsy study previously published. These countries were chosen because of their high frequency of gallstone disease. The comparison was performed by using logistic regression models adjusting for possible differences in the age-sex structure or the true incidence of gallstones in both populations. We found that the most important single risk factor for gallbladdr cancer in Chile was gallstone disease, with an estimated effect on the logistic scale meaning that the cancer risk for subjects with gallstones is seven times higher than for those without the disease. Second in importance was the risk for sex, women being 2.8 times higher than for men. The estimated difference in the sex composition and the incidence of gallstones resulted in 17.9% higher odds of cancer in Chile than in Sweden and Czechoslovakia. However, this difference was not significant. This study suggests that the major etiologic factors of gallbladder cancer in Chileans, Swedes and Czechoslovakians are primarily related to gallstone disease.
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    INTESTINAL METAPLASIA OF THE GASTRIC-MUCOSA IN AUTOPSIES OF CHILEAN ADULTS
    (1984) DUARTE, I; FONK, ML; LLANOS, O; GUZMAN, S
    The frequency and characteristics of intestinal metaplasia of the stomach were studied in autopsy material of 68 Chilean adults, with ages ranging from 30-79 yr. Metaplasia was found in 76.5%, which is in agreement with the high frequency of metaplasia reported from other geographic areas of high incidence for gastric cancer. Of those stomachs with metaplasia, 90.4% had involvement of the lesser curvature, 88.5% of the antral region and only 3.8% did not show the condition in those 2 areas. The metaplasia extended to less than 1/2 of the length of the mucosa in 85.6% of the sections with this change, showing that it is mainly a patchy and multifocal condition. In subjects older than 50 yr, intestinal metaplasia was more extended and severe, and involved with a relative higher frequency the greater curvature and both anterior and posterior walls of the stomach.
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    MALIGNANT PAPILLOMATOSIS OF THE COMMON BILE-DUCT - A CASE DIAGNOSED BY ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY
    (1991) GUZMAN, S; MARTINEZ, J; FORADORI, G; VIAL, T; DUARTE, I
    Bile duct papillomatosis is a rare entity with a high risk of malignant change. We report the case of a 60-year-old man with malignant papillomatosis of the distal common bile duct and a separate carcinoma of ampulla of Vater. The patient had previously undergone surgery for acute cholecystitis and common bile duct calculi. Three months later the patient developed jaundice and fever. An endoscopic retrograde cholangiopancreatography demonstrated multiple filling defects adherent to the wall of the distal common bile duct. Pancreatoduodenectomy was performed with complete resection of the extrahepatic bile duct. Histologic examination showed a multicentric papillary adenocarcinoma of the common bile duct associated with an adenocarcinoma of the ampulla of Vater. The resection margins were free of tumor.
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    METAPLASIA AND PRECURSOR LESIONS OF GALLBLADDER CARCINOMA - FREQUENCY, DISTRIBUTION, AND PROBABILITY OF DETECTION IN ROUTINE HISTOLOGIC SAMPLES
    (1993) DUARTE, I; LLANOS, O; DOMKE, H; HARZ, C; VALDIVIESO, V
    Background. Gallbladder diseases, especially cholelithiasis, are extremely frequent in Chile, and an increasing frequency of gallbladder carcinoma has been observed during the last decades. Hyperplastic and atypical epithelial lesions of gallbladder epithelium have been considered potential precursors of invasive carcinoma. The current study was designed to study the frequency, distribution, extension, and probability of routine detection of potentially preneoplastic changes of gallbladder epithelium.
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    MULTIDRUG RESISTANCE GENE AND P-GLYCOPROTEIN EXPRESSION IN GASTRIC ADENOCARCINOMA AND PRECURSOR LESIONS
    (1991) VOLLRATH, V; CHIANALE, J; GONZALEZ, S; DUARTE, I; ANDRADE, L; IBANEZ, L
    Overexpression of the Multiple Drug Resistance gene (MDR1) has been proposed as a major mechanism related to both intrinsic and acquired resistance to chemotherapeutic agents. The gene product is a membrane protein (P-glycoprotein), that acts as an energy-dependent drug efflux pump decreasing drug accumulation in resistant tumor cells. We have characterized MDR1 and P-Glycoprotein expression in human gastric adenocarcinoma and in precursor lesions. MDR1 mRNAs, analyzed by dot-blot technique, were detected in 9 of 10 non-tumoral gastric mucoase and in 8 of 10 gastric adenocarcinomas. Immunohistochemical analysis, using the MRK16 monoclonal antibody, revealed heterogeneous expression of P-Glycoprotein in individual cells. The P-Glycoprotein was found on the surface of cells of gastric areas with intenstinal metaplasia subtype III. This type of intestinal metaplasia, also called "colonic metaplasia", has been strongly associated with a high risk for the development of gastric cancer. The fact that the P-Glycoprotein was detected in this precursor lesion is consistent with the intestinal metaplasiadysplasia and carcinoma sequence proposed in the histogenesis of this tumor. The finding that P-Glycoprotein was heterogeneously expressed in malignant cells of some gastric adenocarcinomas also suggests that this transporter system probably contributes to primary and secondary multidrug resistance in this neoplasm.
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    PATTERNS OF METASTASES IN INTESTINAL AND DIFFUSE TYPES OF CARCINOMA OF THE STOMACH
    (1981) DUARTE, I; LLANOS, O
    The pattern of the metastases in intestinal and diffuse types of gastric carcinoma were compared in 77 [human] autopsy cases. Differences in the extent of the dissemination, in the distribution of metastases and in the type of secondary involvement were found. The diffuse type of carcinoma showed a wider dissemination than the intestinal type. The intestinal type of carcinoma involved the liver more frequently and more extensively. Peritoneal metastases, lymphatic permeation of the lungs and Krukenberg tumors were more commonly found in cases of the diffuse type.
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    PLACENTAL ALTERATIONS AND INTRAUTERINE GROWTH-RETARDATION ASSOCIATED WITH ENALAPRIL EXPOSURE IN EARLY, MID, AND LATE PREGNANCY IN THE RAT
    (1993) VALDES, G; CHUAQUI, R; CORTHORN, J; DUARTE, I
    Objective: To identify the stage of placental development in which enalapril use in the pregnant rat is deleterious.
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    PLACENTAL ALTERATIONS, INTRAUTERINE GROWTH-RETARDATION AND TERATOGENICITY ASSOCIATED WITH ENALAPRIL USE IN PREGNANT RATS
    (1992) VALDES, G; MARINOVIC, D; FALCON, C; CHUAQUI, R; DUARTE, I
    Enalapril (15 mg/kg/day p.o.) was given to 11 pregnant rats from day 1 to 9 (E1-9) and to 11 rats from day 10 to 20 (E10-20) of pregnancy; 12 rats were the control group. Fifteen animals were sacrificed on day 20 of pregnancy and 19 were allowed to progress into partum. Placentas were smaller in E10-20 rats (-15%, p < 0.05) and had a simple hypocellular cordonal structure; in E1-9 animals the predominant pattern was a combination of complex and simple structure. At day 20 the fetuses in the treated groups were smaller than the controls (-5% in E1-9 and -16% in E10-20, p < 0.05); differences disappeared on the 13th day postpartum. Two fetuses from treated mothers presented incomplete skull ossification. We believe this report adds arguments to preclude converting enzyme inhibitors in pregnancy.