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Biomedical subjects

A Ucar

Publications and source records attributed to A Ucar.

7 recordsLinked to original sources
PubMed2000

A new model for the induction of tumours in the forestomach of rats by N-methyl-N-nitrosourea.

BACKGROUND AND AIM: Experimental carcinogenesis models provide a useful tool in the study of the aetiopathogenesis and treatment of gastric cancer. We developed a model based on the administration of N-methyl-N-nitrosourea (NMU) in Wistar rats for the induction of maximal yield of gastric carcinomas with a short latency period, and being exclusively localized at the gastric level. METHODS: A gastric antiperistaltic fistula was performed in 90 Wistar rats classified into eight different groups. Fifteen days after surgery 5, 10, 15 or 20 mg of NMU/100 g were administered through the fistula once a week for a 3- to 5-week period. Before the administration of NMU, a pyloric blockade was made in order to obtain a temporary isolation of the stomach. At 20 weeks, animals were sacrificed and organs were removed for histological study. RESULTS: All rats treated with 15 mg NMU/100 g once a week for 5 weeks, after pyloric blockade maintained for 1 h, developed well-differentiated carcinomas in the forestomach. Carcinomas were multiple in 11% of cases and appeared with papillomatous lesions in 33% of rats. No tumours were observed in any other organs. In the other groups, no gastric carcinomas were diagnosed. CONCLUSION: The high incidence of carcinomas in the forestomach, the absence of tumours in other organs and the short latency period represent valuable criteria for the use of our model in chemotherapeutic investigations, as well as in the study of cancer evolution without interferences caused by tumour development in other organs.

Animals↗
PubMed1998

Pharmacokinetics of phenprobamate after oral administration to healthy subjects.

Phenprobamate (CAS 673-31-4) is a centrally acting skeletal-muscle relaxant agent. There are only two studies in the literature about the pharmacokinetics of phenoprobamate in man. The inconsistency between the results of these studies can be attributed partly to the different analytical methodologies used. A sensitive, specific and reproducible HPLC-assay, which may increase the reliability of the pharmacokinetic studies of phenprobamate in plasma, has been developed recently. The objective of this investigation was to assess the single-dose kinetics of phenprobamate in human and to determine the pharmacokinetic parameters of clinical and regulatory concern. The plasma pharmacokinetics of phenprobamate have been investigated following single oral administration at a dose of 800 mg in eleven healthy volunteers.

Adolescent↗
PubMed1995

Clinical spectrum of HTLV-I in south Florida.

A total of 113 patients with infection due to human T-cell leukemia virus type 1 (HTLV-I) were evaluated at the University of Miami from January 1988 to March 1993. Forty patients were identified with adult T-cell leukemia/lymphoma (ATLL) and 63 with HTLV-I-associated myelopathy (HAM). Three had concomitant ATLL and HAM. Two HAM patients co-infected with human immunodeficiency virus type 1 (HIV-I) developed clonal lymphoproliferative disease during the study period. Patients with ATLL have a poor prognosis; multiple chemotherapy regimens including high-dose cytotoxic agents have been utilized with a small impact on survival. Most of our patients are currently treated with experimental regimens. Rheumatologic or autoimmune illnesses were identified, mostly in HAM patients, and a small number developed immunodeficiencies in the absence of other definable etiologic factors. Most of the patients were immigrants from areas of endemicity in the Caribbean basin, although many Americans were also recognized. HTLV-I/II infection was diagnosed serologically and typed as HTLV-I by polymerase chain reaction (PCR) or a modified Western blot when a DNA sample was not available. In 24 of 40 patients with ATLL, Southern blot hybridization performed on DNA extracted from peripheral blood lymphocytes or tumor tissue demonstrated clonal HTLV-I integration. In South Florida, ATLL and HAM are now seen frequently. Since HTLV-I infection is associated with a 4% lifetime risk of developing ATLL and an additional 0.25% lifetime risk for developing HAM, a large pool of asymptomatically infected individuals must exist here.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Phase I trial of low dose N-phosphonacetyl-L-aspartic acid and high dose 5-fluorouracil administered concomitantly with radiation therapy for unresectable localized adenocarcinoma of the pancreas.

BACKGROUND: Preclinical and clinical data suggest that N-phosphonacetyl-L-aspartic acid (PALA) can augment the cytotoxic effects of 5-fluorouracil (5-FU). In addition, the combination of 5-FU and radiation therapy has been used with success in prolonging survival and providing palliation of symptoms in patients with advanced unresectable pancreatic carcinoma. This Phase I study was undertaken to determine the feasibility and evaluate the qualitative and quantitative toxicities of PALA and escalating doses of 5-FU administered concomitantly with radiation therapy in patients with locally advanced nonmetastatic pancreatic adenocarcinoma. METHODS: Ten previously untreated patients with advanced nonmetastatic adenocarcinoma of the pancreas were treated with 250 mg/m2 of PALA given as an intravenous bolus followed 24 hours later by 5-FU, which was given by continuous 24-hour infusion every week. The 5-FU doses were assigned according to a Phase I drug escalation (1000 mg/m2, 1300 mg/m2, and 1700 mg/m2). Radiation therapy was delivered concurrently with chemotherapy at a dose of 180 cGy per fraction (900 cGy per week) over 6 1/2 weeks. PALA and 5-FU were continued weekly after the end of radiation therapy, with disease assessments made every 8 weeks. Chemotherapy was continued until the disease progressed. RESULTS: All 10 patients were evaluable. The maximum tolerated dose (MTD) of 5-FU was 1300 mg/m2. Two of the four patients treated at the 1700 mg/m2 dose level experienced dose-limiting toxicities, nausea/vomiting and mucositis, respectively. Toxicities were mild to moderate at the 1000 mg/m2 and 1300 mg/m2 dose levels. Two patients treated with 5-FU at the 1300 mg/m2 dose level had complete responses, and one patient treated at the 1700 mg/m2 dose level had a partial response. The median survival was 12.5 months, and four patients survived more than 1 year. CONCLUSIONS: PALA and 5-FU administered concomitantly with radiation therapy is an active regimen in locally advanced, unresectable pancreatic cancer. Dose-limiting toxicities are nausea/vomiting and mucositis. The MTD of 5-FU is 1300 mg/m2. The regimen is well tolerated and administered in an outpatient setting.

Adenocarcinoma↗
PubMed1994

Thrombotic microangiopathy and retroviral infections: a 13-year experience.

Eleven of fifty serum samples collected from patients with a diagnosis of thrombotic microangiopathy (TMA), from 1979 to 1991, tested positive for antiretroviral antibodies. Seven had human immunodeficiency virus (HIV) infection, and four had human lymphotrophic virus, type I (HTLV-I) infection. All patients were treated with plasma exchange and/or infusion, but only two of the HIV-infected patients obtained a complete response (CR) and one of them died after a few months. Combined results from the literature indicate that most patients with HIV infection survive less than one year from the initial diagnosis of TMA. In the setting of HIV infection, TMA is a treatable condition, but survival for most patients is less than 12 months. Three of the four HTLV-I infected patients with TMA had a CR. These observations strongly suggest that both HIV and HTLV-I infections are associated with TMA, but rigorous epidemiologic studies will be needed to determine the relative risk for each. Retroviral infections should be considered in patients with TMA, especially if the patient has associated risk factors and demographic characteristics.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

[Intraoperative radiotherapy in locally advanced carcinoma of the kidney: initial experience].

Intraoperative radiotherapy (IORT) is a rather interesting therapeutic modality in multidisciplinary oncology. Its greatest advantages reside in the approach of deeply seeded abdomino-pelvic tumors. Its inclusion in the therapeutic approach of renal carcinoma with a high local relapse rate has been analyzed in this study in relation to its technical aspects and preliminary clinical results. 11 stage III or IV patients or with local relapse in lumbar fossa were treated with nephrectomy or exeresis surgery and OIRT (10-20 Gy). Surgical exposure of the lumbar fossa and nodal drainage areas was appropriate in dal cases. No toxic signs or sequellae relating to OIRT were observed. Local tumor controls at 8 months of follow-up on the average (range from 2 to 33 months), was 82%. The data obtained in this series suggest the viability of the combined approach nephrectomy or rescue surgery and IORT. The initial clinical results suggest HIGH local tumor control without an increase in the toxicity rate or complications.

Adenocarcinoma↗