Characterization of type I 5 alpha-reductase activity in DU145 human prostatic adenocarcinoma cells

Each amino acid is represented by a vector of numerical measurements for the attributes of volume, area, hydrophilicity, polarity, hydrogen bonding, shape, and charge. Inter-residue distances are then calculated according to common metrics, and we introduce a new clustering objective function derived from information-theoretic considerations. The arguments of the function are the inter-object distances of the things to be clustered: in this case the amino acids. By means of approximating the solution of an integer programming problem, then, the residues are partitioned into clusters. The clusters obtained are compared with groups obtained in substitution/mutation studies and found to be similar. Thus, probably the strongest and most objective evidence to date is supplied for believing that physico-chemical properties account for the viability of substitutions and that the important similarities/differences are explained by a relatively small and simple set of properties.     

Immortalization of neuroendocrine pinealocytes from transgenic mice by targeted tumorigenesis using the tryptophan hydroxylase promoter

Tryptophan hydroxylase (TPH) is the first enzyme in both serotonin and melatonin biosynthesis in neuroendocrine cells of the pineal gland. The lack of immortalized neuroendocrine pineal cell lines has been a major obstacle to the study of the tissue-specific and circadian regulation of TPH gene expression in the pineal gland. Previously, we demonstrated that a 6.1 kb 5' upstream region of the mouse TPH gene directs the restricted expression of a lacZ reporter gene to the pineal gland and the raphe nuclei of transgenic mice. Therefore, to develop TPH-expressing pineal cell lines we first established transgenic mice carrying a construct consisting of 6.1 kb of 5' flanking region fused to the SV40 T-antigen. These animals developed highly invasive pineal tumors and died at 12-15 weeks of age. The pineal tumors obtained from the transgenic mice were utilized to establish the immortalized pinealocyte-derived cell lines. These cells express two marker enzymes, TPH and serotonin N-acetyltransferase (NAT). In pineal gland TPH and NAT expressions have been known to be regulated during circadian cycle. The two established cell lines therefore promise to be a valuable in vitro model system for the study of the rhythmic nature of the pineal function at molecular level in mammal.     

High temperature low cycle fatigue in beta processed Ti-5Al-5Sn-2Zr-2Mo-0.25Si

The effects ofβ heat treatment andβ-work on microstructure and high temperature low cycle fatigue properties of Ti-5Al-5Sn-2Zr-2Mo-0.25Si were investigated. Strain control tests at total strains ranging from 1.2 to 2.5 pct were conducted at 427, 482, and 538 °C with frequencies of 10 and 0.4 cpm. The results showed shorter fatigue life at the higher temperature and lower frequency for all microstructural conditions.β-worked material with shorterα-platelet structure showed the highest fatigue strength for all test conditions. At these high temperatures, fatigue cracks initiate along theα/β interfaces with longer initial cracks in theβ-annealed condition which had longer interfaces. It is suggested that oxygen diffusion along theα/β interfaces is responsible for surface connected interfacial cracking leading to the observed temperature and frequency dependence. The better HTLCF life of theβ-worked material is related to the shorter initial interface cracks. Formerly with the Metals and Ceramics Division, AFML, W-PAFB, OH 45433     

A PC program for diagnosing abnormal growth, growth velocity and acceleration from longitudinal observations

A human fibroblastic cell line transformed by the SV40-T antigen sequence and continuously cultured for 7 months displayed large periodic variations in cell proliferation. This contrasted with other characteristics of this cell line that remained constant: mosaic cell shape, absence of cell contact inhibition, and predominance of a hypodiploid population. Similar fluctuations in proliferative capacity were also found during the long-term growth of a transformed but nonimmortalized human fibroblastic line prior to senescence, and in the established hamster fibroblastic Nil cell line. This growth pattern suggests a recurrent stimulation of growth in these three transformed cell lines. The proliferation pattern from cultured transformed cells may thus be complex and requires further investigation. These variations presumably influence major cell functions. This observation has important implications for the analysis of data from such cell lines.