Influence of Melatonin on the Proliferative and Apoptotic Responses of the Prostate under Normal and Hyperglycemic Conditions.

The antitumor properties of melatonin (MLT) are known for prostate cancer cells. This study investigated whether MLT affects prostate maturation and interferes with tissue injuries induced by diabetes. MLT was administered to Wistar rats from 5 weeks of age in the drinking water (10 µg/kg b.w.), and diabetes was induced at the 13th week by streptozotocin (4.5 mg/100g b.w., i.p.). The animals were euthanized in the 14th and 21st weeks. MLT reduced the immunostained cells for androgen receptor (AR) by 10% in younger rats. Diabetes decreased cell proliferation and increased apoptosis. MLT treatment impeded apoptosis (p = 0.02) and augmented proliferation (p = 0.0008) and PCNA content in prostate following long-term diabetes due to restoration of testosterone levels and expression of melatonin receptor type 1B. The effect of MLT (500 µM, 5 mM, and 10 mM) on androgen-dependent (22Rv1) and androgen-independent (PC3) cancer cells and human prostate epithelial cells (PNTA1) under normal and hyperglycemic conditions (HG, 450 mg/dL) was analyzed. Contrary to PNTA1 and 22Rv1 cells, MLT improved the proliferation of PC3 cells in hyperglycemic medium. The combined data indicated that MLT had proliferative and antiapoptotic effects in prostate cells subjected to HG levels and it seems to involve specific MLT pathways rather than AR.

Skin-homing CD8+ T lymphocytes show preferential growth in vitro and suppress CD4+ T-cell proliferation in patients with early stages of cutaneous T-cell lymphoma.

A total of 27 T-lymphocyte cell strains were established from skin biopsies of 24 patients with various stages of cutaneous T-cell lymphoma (CTCL) by addition of the T-cell growth factors interleukin (IL)-2 and IL-4. Cellular proliferation and phenotypic changes were measured over 3 months in culture, and T-cell clones were studied using T-cell receptor-? re-arrangement techniques. An average outgrowth of 134 million T-lymphocytes from a 4-mm skin biopsy was observed over 2 months. Initially, most T-cells expressed the CD4+ phenotype. In 17 cell strains from patients with early CTCL a statistically significant predominance of CD8+ T-lymphocytes developed over 8-weeks' culture, indicating that CD8+ T-cells controlled the growth of CD4+ T cells, whereas CD4+ T-cells were predominant in cell strains from advanced CTCL (p <0.05). TCR-? re-arrangement studies revealed, on average, 12 T-cell clones per cell strain, which was reduced over time to 6 T-cell clones per cell strain. Lymphocytes from peripheral blood could kill lymphocytes from an autologous cell strain, suggesting the presence of autoreactive cytotoxic T-cells. Our study suggests how skin-homing CD8+ T-lymphocytes from patients with early stage CTCL can suppress the in vitro growth of skin-homing CD4+ T-lymphocytes, indicating immune surveillance.

Regulated readthrough: a new method for the alternative tagging and targeting of recombinant proteins.

We report here a new method for the alternative peptide tagging of recombinant proteins from mammalian cell lines. This method, which we called regulated readthrough, exploits the property of aminoglycoside antibiotics to promote translational readthrough of nonsense codons. The basic expression cassette includes a translational fusion between a gene of interest and a membrane targeting peptide, which are separated by a nonsense codon. In the presence of an aminoglycoside antibiotic, translational readthrough is promoted and results in the targeting of the fusion protein to the cell membrane, thus allowing the efficient flow cytometry-based isolation of cells expressing very high levels of recombinant protein. For downstream applications requiring the production of soluble recombinant protein, the cells are cultured in the absence of aminoglycoside, leading to an efficient translational termination. By combining different translation termination signals that exhibit various susceptibilities to aminoglycoside-mediated translational readthrough with flow cytometry capabilities, it is possible to use this technology for other applications such as functional library screening or monitoring the stability of recombinant protein production.

Value of flow cytometric assay for the detection of antisperm antibodies in women with a history of recurrent abortion.

PROBLEM: To verify the proposed relationship between recurrent spontaneous abortions and the presence of maternal antisperm antibodies (ASA) in women as detected by a sensitive and reliable method. METHOD OF STUDY: The presence of maternal antipaternal immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies were determined against three different paternal antigens comprising T, B lymphocytes and semen cells by a sensitive flow cytometric crossmatch method to examine their possible correlation with pregnancy outcome. Group 1 consisted of sera obtained from 24 women with a history of abortion, and lymphocytes and semen samples collected from their husbands at the same time of visiting the in vitro fertilization (IVF) Clinic at King Faisal Specialist Hospital and Research Center. Sera, lymphocytes and semen samples were also collected from six couples with no history of abortion who served as controls (Group 2). RESULTS: Using a sensitive flow cytometric assay to analyse the samples, without knowledge of clinical status, elevated levels of both IgG and IgM were detected in Group 1. However, no significant association was found when compared with normal females who had healthy pregnancies. CONCLUSION: Flow cytometry is a highly sensitive and specific tool for the detection of alloantibodies in human sera from patients with rejected transplanted organs. Our findings suggest that maternal antipaternal antibodies with respect to IgG and IgM classes do not play a major role in women with a history of recurrent abortions, despite the presence of increased levels of antibodies against three different sources of paternal antigens.