A search for double beta decays of tin isotopes with enhanced sensitivity

A search for the various double beta decay modes of 124Sn and 112Sn has been performed on 75 kg.days of data. New half-life limits for excited states in 124Sn have been obtained including a lower limit for the decay into the first excited 2+ state of 124Te of T_half > 0.87e20 yrs (90% CL) and into the first excited 0+ state of T_half > 1.08e20 yrs (90% CL). Ground state and excited state transitions of 112Sn have also been experimentally explored. A limit for the 2 neutrino double electron capture of T_half > 1.8e19 yrs (90% CL) is obtained. The non-observation of de-excitation gammas from the 0+ at 1888.5keV results in a lower half-life limit on the 0 neutrino double electron capture decay of 112Sn of T_half > 0.8e19 yrs (90% CL), despite a possible resonant enhancement of the decay rate due to degenerated states.Comment: 6 pages, 7 figures, updated analysis and tex

Expression of Insulinlike Growth Factor (IGF) and IGF-Binding Protein Genes in Human Lung Tumor Cell Lines

Background: The presence of multiple, low-molecular-weight, insulinlike growth factor (IGF)-binding proteins in lung tumor cell-conditioned medium and lung cancer patient serum has been recently reported. Purpose: To begin to elucidate the genetic basis for these observations, the present study examines the expression by lung tumor cell lines of three IGF-binding protein genes, namely, IGFBP-1, IGFBP-2, and IGFBP-3. Since IGF-binding proteins are thought to modulate the biologic action of the IGFs, the relationship between the expression of IGF-binding protein genes and the genes encoding IGF-I and IGF-II also has been investigated. Methods: Gene expression was studied in four small-cell lung cancer (SCLC) and three non—small-cell lung cancer (NSCLC) cell lines using Northern blot analysis and reverse transcriptase polymerase chain reaction (RT-PCR) for IGFBP-1. Results: IGFBP-1 gene expression was detected by Northern blot analysis in one NSCLC cell line only. However, RT-PCR revealed that the IGFBP-1 gene was expressed in all four SCLC cell lines and in two of the three NSCLC lines. Northern blot analysis of IGFBP-2 gene expression demonstrated that all lung tumor cell lines expressed this gene. A low level of IGFBP-3 gene expression was detected in one SCLC cell line and in all three NSCLC cell lines. All lung tumor cell lines expressed the IGF-II gene as determined by Northern blot analysis. In marked contrast, none of the lines showed evidence of IGF-I gene expression using this method. However, RT-PCR revealed a low level of IGF-I gene expression in one SCLC and one NSCLC cell line only. Conclusions: These observations indicate 1) that IGF-binding proteins secreted by lung tumors are encoded by at least three different genes; 2) that there may be a close association between IGF-II and IGFBP-2 gene expression, such that, where there is production of IGF-II, IGFBP-2 is the principal BP; and 3) that the IGF-II gene is more widely expressed than the IGF-I gene in human lung tumor cell lines. [J Natl Cancer Institute 84: 628-634, 1992