Multiple injury approach and its use for toxicity studies

We present an experimental approach that allows exposure of cells plated on a single coverslip to multiple distinct environments. The original chamber design created a small region of injury using geometrically defined flows of the control and ischemic solutions. Modifications of the original chamber design presented in this article produce a range of flow patterns that can be advantageous for a variety of imaging applications. These applications include: experiments that address effects of different treatments applied to a cell network, parallel testing of negative and positive controls using a single coverslip, border effect studies, evaluation of the treatment’s reversibility, and simultaneous monitoring of a cell layer loaded with different fluorescent indicators. The method also can be used to reveal both micro- and macroscopic features of propagation, conduction, and cell coupling in a normal or altered cardia cell network. These possibilities are illustrated in cultures of neonatal rat cardiomyocytes using oxidant-and calcium-sensitive fluorescent indicators.     

Synthesis and biochemical evaluation of some novel benzoic acid based esters as potential inhibitors of oestrone sulphatase

Oestrone sulphatase is an important target in the fight against hormone-dependent breast cancer. In an effort to investigate the reported definitive pharmacophore for oestrone sulphatase and continue our search for potent inhibitors of this enzyme, we have undertaken extensive synthesis, biochemical evaluation and physicochemical property determination of a range of benzoic acid based esters. Here, we report the initial results of our study into a series of straight chain alkyl esters of 4-sulphonylbenzoic acid. Using these compounds, we have investigated the involvement of two physicochemical properties, namely logP and pK(a). The results of this study show that there was a strong correlation between the inhibitory activity and the logP of the parent compound. Within the series of compounds studied, hydrophobicity appears to be a more important factor than pK(a) in determining the overall inhibitory activity. In a previous report, we showed that pK(a) plays an important role in stabilizing the phenoxide ion resulting from the hydrolysis of the sulphamate group. Here, we propose that although pK(a) is an important factor in determining the overall inhibitory activity when a wide range of compounds are considered, both hydrophobicity and pK(a) need to be considered in the design of potential inhibitors of oestrone sulphatase.     

Radiation enhancement by gemcitabine-mediated cell cycle modulations

The purpose of this study was to investigate the exact dose dependency and time dependency of the radiation-enhancing effect of gemcitabine (2',2'difluoro desoxycytidine [dFdC]) in in vitro experiments (HeLa cells: cancer of the uterine cervix, #4197 cells: oropharyngeal squamous cell carcinoma), and to correlate this effect with the underlying changes in cell cycle distribution. Cell viability was determined fluorometrically after exposure to dFdC (0-20.0 micro mol/l), irradiation (0-37.5 Gy), and both modalities. Combining both therapies, cells were exposed to dFdC (0-10.0 micro mol/l) for 24 hours before further treatment and irradiated (0-30 Gy) immediately afterwards with or without removal of dFdC. For cell cycle analysis by flow cytometry, cells were irradiated (0-40 Gy) or treated with dFdC (0.012-1.0 micro mol/l, 24-48 hours). Additionally, cells were exposed to dFdC (2.0 micro mol/l, 0-4 hours). Cell cycle kinetics were evaluated using bromodeoxyuridine (BrdU) (10 micro mol/l) S-phase labeling, given either 30 minutes before or in the last hour of dFdC treatment (2.0 micro mol/l, 0-6 hours). The fluorometric assay revealed that dFdC enhances radiation-induced cytotoxicity at marginally toxic or nontoxic concentrations (<37 nmol/l). Radiation resulted in the anticipated G2/M arrest already at 2 Gy. DFdC induced concentration and exposure time-dependent cell cycle changes that were better resolved using BrdU, demonstrating a pronounced S-phase arrest already at 12 nmol/l. BrdU-pulse labeling revealed that the cell cycle block occurred at the G1/S boundary. Our data reconfirm the already known radiation enhancement, the S-phase specific activities of dFdC, and the relevance of the synchronized progression of cells through the S-phase with regard to the radiosensitizing properties of low-dose dFdC. However, we could demonstrate that before progressing in the S-phase, cells were blocked and partially synchronized at the more radiosensitive G1/S boundary. Furthermore, cells progressing past the block might accumulate proapoptotic signals caused by both radiation and dFdC, which will also results in cell death.     

Chemokines as regulators of T cell differentiation

Chemokines play well established roles as attractants of na?ve and effector T cells. New studies indicate that chemokines also have roles in regulating T cell differentiation. Blocking Gi protein-coupled receptor signaling by pertussis toxin as well as deficiencies in G alpha 12, chemokine receptor 2 (CCR2), CCR5, chemokine ligand 2 (CCL2, also known as monocyte chemoattractant protein 1, or MCP-1), CCL3 (macrophage inflammatory protein 1 alpha, or MIP-1 alpha) and CCL5 (RANTES) have all been found to have effects on the magnitude and cytokine polarity of the T cell response. Here we focus on findings in the CCL2-CCR2 and CCL3-CCR5 ligand-receptor systems. The roles of these molecules in regulating T cell fate include possible indirect effects on antigen-presenting cells and direct effects on differentiating T cells. Models to account for the action of chemokines and G protein-coupled receptor signals in regulating T cell differentiation are discussed.     

Identification of a novel urokinase receptor splice variant and its prognostic relevance in breast cancer

The cellular receptor for urokinase-type plasminogen activator, uPAR, plays a central role in both cell surface-associated proteolysis and cellular adhesion. In the present study, we systematically searched for splice variants of uPAR mRNA in human cells and tumor tissues by qualitative RT-PCR using specific primers for uPAR exons 1 and 6. Beside the wild-type (wt) uPAR mRNA and the previously described splice variant lacking exon 5 (uPAR-del5), a novel splice variant lacking both exons 4 and 5 (uPAR-del4/5) was found predominantly in various cancer cell lines. To elucidate whether alternatively spliced uPAR mRNA may be translated and post-translationally processed, we generated stably transfected Chinese hamster ovary cells, which harbor expression plasmids of wt uPAR and various uPAR variants including uPAR-del5 and uPAR-del4/5. By ELISA, flow cytofluorometry, and Western blot analysis, we confirmed synthesis and secretion of wt uPAR and the uPAR variants by the use of domain-specific monoclonal antibodies against uPAR. For quantification of uPAR mRNA variants, we established two highly sensitive real-time RT-PCR assays based on LightCycler technology. Study of their expression in a representative set of breast cancer tissues indicated that the novel mRNA variant uPAR-del4/5 was expressed very frequently and independently of uPAR mRNA variants covering exon 4 (uPAR-wt and uPAR-del5). Higher uPAR-del4/5 expression was significantly associated with shorter disease-free survival (p = 0.0004) of breast cancer patients. These results suggest that uPAR-del4/5 mRNA may serve as a novel prognostic marker in breast cancer.     

Human lens cells in culture. I. Isolation of adult lens epithelial cells from lens capsule preparations and reactivation of nucleus-containing fiber cells

BACKGROUND: Bovine lens epithelial cells in culture revealed a high sensitivity against micromolar concentrations of linoleic acid. To prove the assumption that unsaturated free fatty acids are risk factors for cataractogenesis, human lens cell lines are needed. Furthermore, the reactivation of nucleus-containing fiber cells to mitotic growth may hint at their role in after cataract genesis. MATERIAL AND METHODS: Epithelium-capsule-preparations obtained by capsulorhexis were cultured in serum containing medium. Subculturing of these adult human lens epithelial cells was done by trypsinization. Fiber cell bundles from the equator region of a fetal human lens were transferred into culture medium. Aggregates of nucleus containing fiber cells were isolated from floating fiber cell bundles by trypsinization. Subculturing and cryoconservation of suitable cell lines. RESULTS: Primary culture of epithelium-capsule-preparations results in flattening, migration and proliferation of adult human lens epithelial cells. Nucleus containing fiber cells were reactivated to mitotic growth after adhesion to a suitable substratum. Established cell lines were received from adult human lens epithelial cells and fetal human fiber cells after repeated subculturing. CONCLUSIONS: Lens-capsule-preparations available from cataract surgery are well suited for the isolation of human lens cell lines, which were needed for testing cytotoxicity of drugs and for tracing of cataractogenic risk factors. The finding that nucleus containing fiber cells from the equator of human lenses can be reactivated to proliferating cells let us suppose, that these cells, which can not be removed easily from the posterior lens capsule, contribute to the after cataract formation.     

Tolerability of combined treatment with lithium and paroxetine in patients with bipolar disorder and depression

Patients with bipolar disorder are often prescribed lithium in combination with a selective serotonin reuptake inhibitor. Doubts still remain, however, about the safety of the combination, particularly with regard to the risk of developing a serotonin syndrome. The authors retrospectively evaluated the safety of the combination of lithium and paroxetine when the two medications were sequentially prescribed in patients with bipolar disorder. The authors examined a sample of 17 patients with bipolar disorder who were treated with lithium during a depressive episode and who required paroxetine as an adjunctive antidepressant to ongoing lithium treatment. Averaging across all subjects, no statistically significant increase was found for any of the somatic symptoms that were assessed before and after paroxetine was added to ongoing lithium therapy. Examining the clinical records of each patient in detail; however, four patients who developed significant adverse events, possibly related to an emerging serotonin syndrome were identified. Clinicians should be aware of the possible development of a serotonin syndrome among patients in whom paroxetine is added to ongoing lithium treatment.     

Intestinal transplantation in children

Intestinal transplantation has emerged in the last decade as a lifesaving procedure for patients with intestinal failure who are suffering from complications arising from the administration of total parenteral nutrition. Indications for transplantation include irreversible liver injury and loss of vascular access. At least 50 children in the United States may benefit from intestinal transplantation every year. In this article, indications, pre-and postoperative management, and outcomes of intestinal transplantation in children are discussed.