Genomic imprinting and Igf2 influence liver tumorigenesis and loss of heterozygosity in SV40 T antigen transgenic mice

Maternal-specific loss of heterozygosity (LOH) and allelic imbalances [i.e., partial LOH (pLOH)] observed in SV40 T/t antigen-induced liver tumors suggests that an imprinted gene on chromosome 7 is involved in liver tumorigenesis. Maternal-specific LOH/pLOH may reflect the loss of a maternally expressed tumor suppressor gene or the acquisition of paternally active alleles of a growth promoter. In addition, two oppositely imprinted genes on distal chromosome 7, Igf2 and H19, are re-expressed in most liver tumors from an SV40 T/t antigen transgenic line (M11T-G). Igf2 is a paternally expressed growth promoter, and H19 is a maternally expressed gene that can suppress growth in some tumor cell lines. We studied the role of Igf2 during liver tumorigenesis by creating Igf2 (+/-) M11T-G mice. These mice are essentially null for Igf2 expression because imprinting normally precludes maternal Igf2 expression. M11T-G, Igf2 (+/-) males exhibit a 15-fold reduction in the frequency of large tumors. Igf2 (+/-) tumors do not express maternal Igf2, indicating rigid imprinting control in the liver. LOH/pLOH analysis was performed on the tumors and indicates that acquisition of paternally active Igf2 alleles is a major selective event for M11T-G liver tumorigenesis. This also implies the existence of an imprinted, maternally expressed tumor suppressor gene on chromosome 7 that is unlikely to be H19.     

Photocatalytic and Photochemical Oxidation of Ethylene: Potential for Storage of Fresh Produce—a Review

The phytohormone ethylene exerts numerous beneficial and detrimental effects on postharvest quality and storage life of fruit and vegetables. In view of the current global challenge of reducing postharvest losses and waste of fruit and vegetables, the importance of ethylene management in the supply chain is paramount. For this purpose, various methods have been applied along the supply chain over the years; however, effective management of ethylene under real-time storage and transport conditions still remains a challenging task. This review explores the potential of photocatalytic and photochemical oxidation of ethylene for effective removal of this gas along the value chain of fruit and vegetables. These techniques involve the use of ultraviolet (UV) radiation with or without a catalyst. In photocatalytic oxidation, a semiconductor such as titanium dioxide is essential which acts as a photocatalyst on irradiation with UV light and thus facilitates the oxidation of ethylene at its surface, whereas in photochemical oxidation, extreme short wave (i.e. below 200 nm) vacuum ultraviolet radiation (VUV) consisting of high-energy photons eliminates ethylene in the gaseous state. This review gives a brief overview of current commercial techniques used in ethylene removal and then focuses on the photocatalytic and the photochemical oxidation of ethylene and the combination of both methods. The various factors affecting these processes are also discussed including the advantages and the drawbacks associated with them, and current applications of these methods in fruit and vegetable storage systems are highlighted. In addition, a future outlook on the application of these methods in postharvest storage of fresh produce is given.     

Correlation of 3D MRI and clinical findings in the patients with sensorineural hearing loss and/or vertigo

The aim of the study was to correlate clinical and magnetic resonance imaging (MRI) (3D CISS and MP-RANGE) findings in patients with sensorineural hearing loss (SNHL) and/or vertigo. We found a high correlation of MRI and symptoms (17 out of 18 patients, 13 out of 13, respectively) concerning detectability of tumors and acute labyrinthitis. In the case of labyrinthine fibrosis, the correlation between clinical and MRI findings was lower. In conclusion, high-resolution MRI is very suitable in patients with SNHL or vertigo caused by tumors or acute labyrinthitis.     

T cells from patients with Hodgkin's disease have a defective T-cell receptor zeta chain expression that is reversible by T-cell stimulation with CD3 and CD28

To investigate the mechanisms underlying the deficiency of T lymphocytes from patients with Hodgkin's disease, we investigated the expression of the T-cell receptor (TCR) zeta chain in patients with Hodgkin's disease. By flow cytometry using an anti-zeta chain monoclonal antibody, peripheral blood T lymphocytes from patients with untreated Hodgkin's disease were shown to express decreased levels of the TCR zeta chain. After stimulation by combined CD3 and CD28 cross-linking, T cells from Hodgkin's disease patients upregulated zeta chain protein expression to normal values within 48 hours and achieved a cytolytic potential and levels of interleukin (IL)-2 secretion that were not different from T cells obtained from healthy controls. These results show that downregulation of the TCR zeta chain in Hodgkin's T lymphocytes is a reversible event. Costimulation of CD3 and CD28 is a novel approach for overcoming the T-cell deficiency in Hodgkin's disease and might be exploited clinically. As upregulation of the zeta chain can also be achieved using bispecific monoclonal antibodies (BI-MoAbs) with specificity for tumor antigens and CD3 and CD28, respectively, an immunotherapy with CD3/CD30 and CD28/CD30 Bi-MoAbs may overcome and should therefore, not be jeopardized by the inherent T-cell deficiency in patients with Hodgkin's disease.