Melatonin induces changes to serum cytokines in mice infected with the Venezuelan equine encephalomyelitis virus

We determined the influence of melatonin (MLT) on the induction of interleukin (IL)-2, IL-1 beta, IL-4, tumour necrosis factor-alpha (TNF-alpha) and gamma interferon (IFN-gamma) on mice infected with the Venezuelan equine encephalomyelitis (VEE) virus. Levels of IFN-gamma in the MLT-treated group were significantly increased (P < 0.001) when compared with the control non-infected group from day 1 to 6 post-infection (p.i.), while in infected mice treated with 500 micrograms MLT/kg of bodyweight enhanced levels of IFN-gamma were evident from 4 to 6 days p.i. No differences were detected in the levels of IL-2 between the controls, the infected mice treated with MLT and the infected untreated group, from day 2 p.i. No changes in serum levels of IL-4 were detected. In infected mice treated with MLT, blood levels of IL-1 beta were elevated almost 10-fold from day 1 to day 6 p.i. when compared to the control, the infected and the non-infected MLT-treated mice (P < 0.001). A highly significant rise (P < 0.001) of TNF-alpha was found in infected mice treated with MLT, from day 1 to 6 p.i. when compared to the other groups. A significant rise (P < 0.001) was also evident in the infected non-MLT-treated group and a less pronounced rise in the non-infected mice treated with MLT when compared to controls. The blockade of IFN-gamma and TNF-alpha did not inhibit the protective effect of MLT but when IL-1 beta was neutralized, 100% of the infected mice died suggesting that IL-1 beta induced by MLT treatment is a target cytokine to generate an immune response against the viral infection.     

Bronchobiliary fistulae between a liver hydatid cyst and the middle lobe of the right lung

We report a case of bronchobiliary fistula between a liver hydatid cyst and the middle lobe of the right lung. It is also reviewed the etiology, pathogenesis, clinical features, diagnosis and treatment of bronchobiliary fistulas.     

A BPA survey of recently appointed consultants

A postal survey of recently appointed consultant paediatricians was undertaken to determine whether they perceived their training had adequately equipped them for their current job. The response rate was 69% (207/299). After excluding replies from consultants trained outside the UK the analysis was carried out on 167 replies. Trainees held a mean 5.2 posts during general and higher professional training, necessitating a mean 1.8 house moves. Altogether 82% felt moves were beneficial to training but 46% found moves 'very disruptive' to family life. Only 12% of district general hospital and 22% of teaching hospital senior registrars took two research sessions a week. Supervision and training in research was absent or poor for more than 60%; 24% felt major changes and 55% moderate changes were needed to current training. Training in non-clinical skills was particularly in demand and a curriculum for both trainers and trainees with regular appraisals is required. Research at senior registrar level needs review and educational methods improved to achieve better training in a shorter period.     

Long-term hydroxytamoxifen treatment of an MCF-7-derived breast cancer cell line irreversibly inhibits the expression of estrogenic genes through chromatin remodeling

Antiestrogen resistance is frequently observed in patients after longterm treatment with tamoxifen, a nonsteroidal antiestrogen widely used for endocrine therapy of breast cancer. In vitro studies in resistant cells showed that the expression of natural estrogen-responsive genes is frequently altered. Using MVLN cells, an MCF-7-derived cell model, we previously demonstrated that 4-hydroxytamoxifen (OHT) treatment irreversibly inactivated an estrogen-regulated chimeric luciferase response by a direct effect of the drug and not through a cell selection process (E. Badia et al., Cancer Res., 54: 5860-5866, 1994). In the present study, we present tamoxifen-resistant but still estrogen-dependent clones isolated after long-term treatment of MVLN cells with OHT and show that progesterone receptor (PR) expression was irreversibly decreased in some of these clones, whereas the PRA:PRB ratio of residual PR remained unchanged. The irreversible inactivation of both chimeric luciferase gene and PR gene expression was associated with the disappearance of DNase 1-hypersensitive sites. In the case of the chimeric gene, at least one of these sites was close to the estrogen responsive element. Genomic sequencing analysis of a clone with very low PR content did not reveal any methylation on CpG dinucleotides or any mutation in the PR gene promoter region. In all of the resistant clones tested and independently of their PR content, estrogen receptor expression was only lowered by half and remained functional, whereas pS2 expression was not modified. We also observed that the residual luciferase activity level (1-2%) of the MVLN clones, the luciferase expression of which had been irreversibly inactivated, was raised 4-fold by trichostatin A treatment. We conclude that long-term OHT treatment may modify the chromatin structure and thus could contribute to differentially silencing natural target genes.     

Reporter Cell Lines to Monitor Steroid and Antisteroid Potential of Environmental Samples

In order to monitor the (anti)steroid activity of environmental samples, we established stable cell lines expressing luciferase under the control of estrogens, androgens, progestives and glucocorticoids. The breast cancer MCF-7 cells which express the estrogen receptor (ER), the glucocorticoid receptor (GR) and the progesterone receptor (PR) were transfected by an estrogen (ERE-Glob-Luc) or a glucocorticoid/progestin/androgen (MMTV-Luc) regulated luciferase plasmid in order to enable the detection of compounds which bind both ER, PR and GR (MELN and MMLN cells). Human prostatic cells PC3 were stably transfected by both an androgen receptor gene and the MMTV-luciferase plasmid (PALM cells). These three cellular models were validated as tools to check the estrogenic, progestive, glucocorticoid and androgenic activities using several potential xenohormones and environmental samples. As these environmental samples were fractionated after solid phase extraction to isolate active compounds, we used these cellular models to monitor the different fractions. In the estrogenic model mid-polar fractions of environmental samples were found active while in the androgenic model, the same fractions had antagonist activity.     

Molecular biology of malignant melanoma and other cutaneous tumors

Skin cancer is the most common cancer worldwide. Its incidence is doubling every 15–20 years likely because of an aging population, changes in behaviour towards sun exposure, and increased UV light fluency at the earth surface due to ozone depletion. In this review, we summarize the most important genetic changes contributing to the development of malignant melanoma, basal cell carcinoma and squamous cell carcinoma, the main tumor entities arising in the skin. While our understanding of the oncogenes and tumor suppressor genes involved in the development and progression of skin tumors is still fragmentary, recent advances have shown alterations affecting conserved signalling pathways that control cellular proliferation and viability. These pathways includeINK4a/Rb,ARF/p53, RAS/MAPKs, and sonic hedgehog/Gli. Supported by an unrestricted educational grant by Bristol-Myers Squibb.