Establishment and Characterization of Novel Human Intestinal In Vitro Models for Absorption and First-Pass Metabolism Studies

Commonly used intestinal in vitro models are limited in their potential to predict oral drug absorption. They either lack the capability to form a tight cellular monolayer mimicking the intestinal epithelial barrier or the expression of cytochrome P450 3A4 (CYP3A4). The aim of this study was to establish a platform of colorectal cancer patient-derived cell lines for evaluation of human intestinal drug absorption and metabolism. We characterized ten 2D cell lines out of our collection with confluent outgrowth and long-lasting barrier forming potential as well as suitability for high throughput applications with special emphasis on expression and inducibility of CYP3A4. By assessment of the transepithelial electrical resistance (TEER) the cells barrier function capacity can be quantified. Very high TEER levels were detected for HROC60. A high basal CYP3A4 expression and function was found for HROC32. Eight cell lines showed higher CYP3A4 induction by stimulation via the vitamin D receptor compared to Caco-2 cells (5.1- to 16.8-fold change). Stimulation of the pregnane X receptor led to higher CYP3A4 induction in two cell lines. In sum, we identified the two cell lines HROC183 T0 M2 and HROC217 T1 M2 as useful tools for in vitro drug absorption studies. Due to their high TEER values and inducibility by drug receptor ligands, they may be superior to Caco-2 cells to analyze oral drug absorption and intestinal drug–drug interactions. Significance statement: Selecting appropriate candidates is important in preclinical drug development. Therefore, cell models to predict absorption from the human intestine are of the utmost importance. This study revealed that the human cell lines HROC183 T0 M2 and HROC217 T1 M2 may be better suited models and possess higher predictive power of pregnane X receptor- and vitamin D-mediated drug metabolism than Caco-2 cells. Consequently, they represent useful tools for predicting intestinal absorption and simultaneously enable assessment of membrane permeability and first-pass metabolism.     

Differential regulation of chordin expression domains in mutant zebrafish

Patterning along the dorsal-ventral (D-V) axis of Xenopus and Drosophila embryos is believed to occur through a conserved molecular mechanism, with homologous proteins Chordin and Short gastrulation (Sog) antagonizing signaling by bone morphogenetic protein 4 (BMP-4) and Decapentaplegic (Dpp), respectively. We have isolated a zebrafish gene that is highly homologous to chordin and sog within cysteine-rich domains and exhibits conserved aspects of expression and function. As in Xenopus embryos, zebrafish chordin is expressed in the organizer region and transiently in axial mesoderm. Injection of zebrafish chordin mRNA to the ventral side of Xenopus embryos induced secondary axes. Ectopic overexpression in zebrafish resulted in an expansion of paraxial mesoderm and neurectoderm at the expense of more lateral and ventral derivatives, producing a range of defects similar to those of dorsalized zebrafish mutants (Mullins et al., 1996). In accordance with the proposed function of chordin in D-V patterning, dorsalized zebrafish mutants showed expanded domains of chordin expression by midgastrulation, while some ventralized mutants had reduced expression; however, in all mutants examined, early organizer expression was unaltered. In contrast to Xenopus, zebrafish chordin is also expressed in paraxial mesoderm and ectoderm and in localized regions of the developing brain, suggesting that there are additional roles for chordin in zebrafish embryonic development. Surprisingly, paraxial mesodermal expression of chordin appeared unaltered in spadetail mutants that later lack trunk muscle (Kimmel et al., 1989), while axial mesodermal expression was affected. This finding reveals an unexpected function for spadetail in midline mesoderm and in differential regulation of chordin expression during gastrulation.     

Retinal detachment following phacoemulsification in highly myopic cataract patients

OBJECTIVE: To compare trifluridine eyedrops, cidofovir eyedrops, and penciclovir ophthalmic ointment for the treatment of herpes simplex virus type 1 keratitis. METHODS: New Zealand white rabbits were infected with the McKrae strain of herpes simplex virus type 1. Three days after viral inoculation, the rabbits were randomly assigned to treatment with 1% trifluridine, 0.2% cidofovir, 3% penciclovir ointment, or phosphate-buffered saline (for control) on various schedules. The severity of keratitis was graded in a masked manner. RESULTS: Treatment with any of the antiviral drugs resulted in significantly less severe keratitis than treatment with phosphate-buffered saline. There was no statistically significant difference between eyes given trifluridine 2, 4, or 7 times a day and eyes given cidofovir 2 times a day (P=.06, P=.43, and P=.19, respectively, using the F test of the analysis of variance). Cidofovir given twice a day was significantly more effective than penciclovir given either 2 or 4 times a day (P<.001 and P=.002, respectively). Even with once-a-day dosage, all 3 drugs were significantly more effective than phosphate-buffered saline (P<.001 for all). There was no significant difference between once-a-day trifluridine and cidofovir treatments (P=.17). Trifluridine administered 5 times a day was as effective as 1% cidofovir. A similar degree of punctate keratitis was seen after 4 to 5 days in eyes treated with trifluridine at the highest frequency, 1% cidofovir, or penciclovir ointment. CONCLUSION: Trifluridine treatment was highly effective in this rabbit model, even when given only once a day. Treatment with cidofovir was as effective as that with trifluridine. CLINICAL RELEVANCE: Cidofovir and penciclovir treatments may prove to be effective against epithelial keratitis. Clinical trials of trifluridine, cidofovir, and penciclovir with lower treatment frequencies appear to be warranted.     

Can we improve the uptake of gastroscopy in the population at risk for gastric cancer? The effect of home letter information

PURPOSE: To investigate whether a significant proportion of prostate cancer patients who have late sequelae after high-dose external-beam conformal radiation therapy are radio-sensitive because they are carriers of ataxia-telangiectasia, that is, are heterozygous for mutations in the ATM gene. PATIENTS AND METHODS: A group of prostate cancer patients were selected who experienced severe late sequelae, specifically proctitis or cystitis, after high-dose external-beam conformal radiation therapy, together with a control group of patients treated in the same way but who did not have severe late effects. Blood samples were taken from these patients, genomic DNA extracted, and mutations sought in the ATM gene. RESULTS: Of 17 late-effect patients in whom most or all of the ATM gene has been examined, significant mutations (17.6%) were identified in three. No significant mutations were found in the control group. The incidence of ataxia- telangiectasia heterozygotes in the United States population is 1% to 2%. DISCUSSION: These preliminary data suggest that a disproportionate number, but by no means all, of prostate cancer radiotherapy patients who experience severe late effects are ataxia-telangiectasia heterozygotes. If this conclusion is confirmed, these individuals could be identified prospectively and, with dose de-escalation, spared a great deal of discomfort and suffering. As a corollary, if most of the small late-effects population were prospectively identifiable, the dose to the remaining population could potentially be escalated. Present methods of identifying mutations in a large gene, such as ATM, are cumbersome and expensive, but the technology is evolving rapidly, so that rapid screening of the ATM gene is imminent.     

An unreported cause of rupture of the extensor pollicis longus tendon

Avulsion fractures of the index metacarpal at the insertion of extensor carpi radialis longus are rare. We report such a fracture and the resulting complication of division of the extensor pollicus longus tendon, by the avulsed bony fragment. Careful clinical assessment and appropriate radiological examination is needed to diagnose this rare fracture and internal fixation is recommended.     

Cervical human immunodeficiency virus type 1 shedding is associated with genital beta-chemokine secretion

Forty human immunodeficiency virus type 1 (HIV-1)-infected women participated in a cross-sectional study of possible correlations between chemokine receptor (CCR5 and/or CCR2B) genotype, HIV-1 RNA and DNA load, and beta-chemokine levels (RANTES, MIP-1alpha, MIP-1beta) in blood and cervix. HIV-1 nucleic acid and beta-chemokines were found in all patient blood samples and in more than half of the cervical samples regardless of CCR5 or CCR2B genotype. High beta-chemokine concentrations were in general associated with high virus loads in blood and cervix. In the blood, the proviral DNA load was significantly correlated with the MIP-1alpha concentration, whereas the DNA load in cervix was significantly associated with the MIP-1beta concentration. The cervical viral RNA load was significantly associated with levels of all three chemokines. Thus, when HIV-1 shedding was highest in the genital tract, it was associated with other combinations of beta-chemokines than virus load in blood, suggesting that local immune reactions strongly influence virus load in the cervical compartment.     

Windsor twenty-five years on: The continuing presence of a 1970s freeway plan in inner Brisbane

In June 1972, the Queensland Main Roads Department (MRD) announced its intention to construct the Northern Freeway through Brisbane's inner north. Only the land acquisition stage was ever completed, with freeway construction being indefinitely postponed in 1975. Yet, the plan remains officially gazetted, suggesting that the Freeway, or an alternative road, will eventually be built. In considering this long-dormant plan and the suburbs through which the freeway was to have been constructed, this paper focuses on three related issues. The first is whether this dormant phase had any negative effects on the households who lived in the suburbs through which the freeway was to have been built. The second is whether the freeway, or an alternative road system, will ever be constructed. The third is the potential social impact on the suburbs today if this freeway, or an alterative road, were built.     

The Social Exclusion Perspective and Housing Studies: Origins,Applications and Limitations

The idea of 'social exclusion' has emerged over a relatively short space of time to take centre stage in political and popular debates about social disadvantage in many European states. In Britain it now dominates policy discourse on strategies to combat disadvantage.This paper explores the origins of the concept of social exclusion and the meanings that have been ascribed to it. The paper poses questions which remain outstanding in the debate over social exclusion. It then considers the relationship between housing and social exclusion and introduces each of the papers in the special issue. It finishes by noting that the papers in this issue make a significant contribution to enhancing our understanding of processes of disadvantage,but that there is much that remains to be done.