Average bioequivalence of single 500 mg doses of two oral formulations of levofloxacin: a randomized, open-label, two-period crossover study in healthy adult Brazilian volunteers

Average bioequivalence of two 500 mg levofloxacin formulations available in Brazil, Tavanic(c) (Sanofi-Aventis Farmacêutica Ltda, Brazil, reference product) and Levaquin(c) (Janssen-Cilag Farmacêutica Ltda, Brazil, test product) was evaluated by means of a randomized, open-label, 2-way crossover study performed in 26 healthy Brazilian volunteers under fasting conditions. A single dose of 500 mg levofloxacin tablets was orally administered, and blood samples were collected over a period of 48 hours. Levofloxacin plasmatic concentrations were determined using a validated HPLC method. Pharmacokinetic parameters Cmax, Tmax, Kel, T1/2el, AUC0-t and AUC0-inf were calculated using noncompartmental analysis. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of Cmax, AUC0-t and AUC0-inf values for test and reference products, using logarithmic transformed data. Tolerability was assessed by monitoring vital signs and laboratory analysis results, by subject interviews and by spontaneous report of adverse events. 90% CIs for Cmax, AUC0-t and AUC0-inf were 92.1% - 108.2%, 90.7% - 98.0%, and 94.8% - 100.0%, respectively. Observed adverse events were nausea and headache. It was concluded that Tavanic(c) and Levaquin(c) are bioequivalent, since 90% CIs are within the 80% - 125% interval proposed by regulatory agencies

Cohort migration of carcinoma cells: Differentiated colorectal carcinoma cells move as coherent cell clusters or sheets

Active migration of tumor cells is usually assessed as single cell locomotion in vitro using Royden chamber-type assays. In vivo, however, carcinoma cells, malignant cells of epithelial origin, frequently invade the surrounding tissue as coherent clusters or nests of cells. We have called this type of movement "cohort migration". In our work, the invasion front of colon carcinomas consisted of compact tumor glands, partially resolved glands or markedly resolved glands with scattered tumor cell clusters or single cells lying ahead. In the former two types, which constituted about a half of all cases, cohort migration seems to be the predominant mechanism, whereas both cohort migration and single cell locomotion may be involved in the last one. In this light, it is very advantageous to investigate the mechanisms involved in the cohort migration. In this review, we present a two-dimensional motility assay as a cohort migration model, in which human colorectal carcinoma cells move outwards from the cell islands mainly as localized coherent sheets of cells when stimulated with 12-0-tetradecanoylphorbol- 13-acetate (TPA) or hepatocyte growth factorlscatter factor (HGFISF). Within the migrating cell sheets, wide intercellular gaps occur at the lower portion of the cells to allow the cells to extend leading lamellae forward while close cell-cell contacts remain at the upper portion of the cells. This localized modulation of cell-cell adhesion at the lower portion of the cells is associated with increased tyrosine phosphorylation of the Ecadherin- catenin complex in TPA-induced cohort migration and with reduced α-catenin complexed with E-cadherin in HGFISF-induced cohort migration. Furthermore, fibronectin deposited by migrating cells is essential for their movement, and on the gelatin-coated substrate even degradation and remodeling of the substrate by matrix metalloproteinases are also needed. Thus, in cohort migration it is likely that cells are released from cell-cell adhesion only at the lower portion of the cells via modulation of E-cadherin-catenin-based mechanism, and this change allows the cells to extend leading lamellae onto the extracellular matrix substrate remodeled by deposition of fibronectin and organized digestion

PERGAMON Expert tutoring system for teaching computer programming languages

This paper presents an Expert tutoring system (E-TCL) for teaching computer programming languages through WWW. In this version, many teachers can cooperate together to put the curriculum of one/more computer programming language(s). Their contributions may include: (a) add or modify the commands ’ structure that will be taught; (b) generate different tutoring dialogs for the same command; and (c) generate different tutoring styles. On the contrary, the students can access the system through WWW, select any language they want to learn as well as the style of presentation they prefer and they can exchange their experiences. A personal assistant agent for teachers (PAA-T), a personal assistant agent for students (PAA-S) with an adaptive interface, and tutoring agent (TA) has been built. The TA resides on the server side and communicates via HTTP and IIOP with both the PAA-T and PAA-S on the clients side. This structure allows customization of the PAA-T and PAA-S to the needs of the teachers and students, without putting extra burden on the server. In addition, this allows having many teacher agents attending to the needs of a single or multiple student agent(s). � 2000 Elsevier Science Ltd. All rights reserved

Cohort migration of carcinoma cells.Differentiated colorectal carcinoma cells move as coherent cell clusters or sheets

Active migration of tumor cells is usually assessed as single cell locomotion in vitro using Royden chamber-type assays. In vivo, however, carcinoma cells, malignant cells of epithelial origin, frequently invade the surrounding tissue as coherent clusters or nests of cells. We have called this type of movement "cohort migration". In our work, the invasion front of colon carcinomas consisted of compact tumor glands, partially resolved glands or markedly resolved glands with scattered tumor cell clusters or single cells lying ahead. In the former two types, which constituted about a half of all cases, cohort migration seems to be the predominant mechanism, whereas both cohort migration and single cell locomotion may be involved in the last one. In this light, it is very advantageous to investigate the mechanisms involved in the cohort migration. In this review, we present a two-dimensional motility assay as a cohort migration model, in which human colorectal carcinoma cells move outwards from the cell islands mainly as localized coherent sheets of cells when stimulated with 12-0-tetradecanoylphorbol- 13-acetate (TPA) or hepatocyte growth factorlscatter factor (HGFISF). Within the migrating cell sheets, wide intercellular gaps occur at the lower portion of the cells to allow the cells to extend leading lamellae forward while close cell-cell contacts remain at the upper portion of the cells. This localized modulation of cell-cell adhesion at the lower portion of the cells is associated with increased tyrosine phosphorylation of the Ecadherin- catenin complex in TPA-induced cohort migration and with reduced a-catenin complexed with E-cadherin in HGFISF-induced cohort migration. Furthermore, fibronectin deposited by migrating cells is essential for their movement, and on the gelatin-coated substrate even degradation and remodeling of the substrate by matrix metalloproteinases are also needed. Thus, in cohort migration it is likely that cells are released from cell-cell adhesion only at the lower portion Offprint requests to: Dr. Kazuki Nabeshima, Department of Pathology, Miyazaki Medical College, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan. e-mail: [email protected] Histology and Histopathology of the cells via modulation of E-cadherin-catenin-based mechanism, and this change allows the cells to extend leading lamellae onto the extracellular matrix substrate remodeled by deposition of fibronectin and organized digestion

Front-cell-specific expression of membrane-type 1 matrix metalloproteinase and gelatinase A during cohort migration of colon carcinoma cells induced by hepatocyte growth factor/scatter factor.

Migration of tumor cells is usually assessed as single cell locomotion in vitro using Boyden chamber type assays. In vivo, however, carcinoma cells frequently invade the surrounding tissue as coherent clusters or nests of cells. We have called this type of movement "cohort migration" and developed a two-dimensional in vitro cohort migration model, in which human rectal well-differentiated adenocarcinoma cells (L-10) migrate from piled-up cell islands as coherent sheets of cells when stimulated with hepatocyte growth factor/scatter factor. In this study, we examined whether there is a cohort migration-specific way of expression of matrix metalloproteinases (MMP) and whether degradation of extracellular matrix is necessary for this type of migration. Production of membrane-type 1-MMP (MT1-MMP) and gelatinase A (MMP-2) by L-10 cells was demonstrated by gelatin zymography, immunoblotting, and reverse transcription-PCR. When cohort migration was induced with hepatocyte growth factor/scatter factor, MT1-MMP and MMP-2 were immunolocalized predominantly in the leading edges of the front cells of migrating cell sheets, with the following cells being negative. In addition, during the cohort migration on gelatin-coated substratum, the gelatin matrix was degraded by the cells, in a very organized manner, causing radially arrayed lysis of gelatin matrix at the sites of leading edges. BB94, a synthetic inhibitor specific to MMPs, tissue inhibitor of metalloproteinases-1 and -2, and the COOH-terminal hemopexin-like domain of MMP-2 inhibited the migration on gelatin matrix. Thus, these data demonstrate that gelatin matrix is reorganized to suit cell migration via leading-edge-of-front-cell-specific localization of MT1-MMP and MMP-2 during cohort migration and suggest that the reorganization is essential for this type of migration