An epidemiological study of reproductive function biomarkers in male welders

In a cross-sectional study, the serum concentrations of inhibin B and prolactin of 96 male current welders were compared with the concentrations measured in 96 age-matched referents. Also, 23 patients who were all former welders diagnosed as having welding-related manganism were studied. The current welders' geometric mean (GM) airborne exposure to manganese (Mn) was 121 µg m^-3 (range 7-2320). The serum concentrations of prolactin adjusted for age and smoking habits (GM 193 mIU l^-1 vs. 166 mIU l^-1; p=0.047) and inhibin B adjusted for alcohol consumption (arithmetic mean (AM) 151 ng l^-1 vs. 123 ng l^-1; p=0.001) were higher in the welders compared with the referents. The whole blood Mn concentration was associated with the serum prolactin concentrations. Tobacco smoking resulted in lower serum prolactin concentrations. The GM serum prolactin concentrations of the patients did not significantly differ from that of the referents, but their AM serum inhibin B concentration was statistically significantly lower. The results may suggest an effect of Mn on the pituitary that is reversible upon cessation of exposure. Lower inhibin B concentrations in the patients could point to a functional impairment of the testicular Sertoli cells, that may be caused by a welding fume component or other factors in their work environment.     

Translation initiation factor 4E blocks endoplasmic reticulum-mediated apoptosis

Eukaryotic translation initiation factor 4E (eIF4E) is the mRNA cap-binding protein required for translation of cellular mRNAs utilizing the 5' cap structure. The rate-limiting factor for mRNA recruitment to ribosomes, eIF4E is a major target for regulation of translation by growth factors, hormones, and other extracellular stimuli. When overexpressed, eIF4E exerts profound effects on cell growth and survival, leading to suppression of oncogene-dependent apoptosis, causing malignant transformation and conferring tumors with multiple drug resistance. We found previously that overexpressed eIF4E interdicts the apoptotic pathway induced by growth factor withdrawal and cytotoxic drugs by selectively activating the expression of Bcl-X(L), thus preventing mitochondrial release of cytochrome c. In this study, we examined the impact of ectopic eIF4E expression on apoptosis mediated by the endoplasmic reticulum (ER). Here we show that eIF4E rescued cells from the ER stressors brefeldin A, tunicamycin, thapsigargin, and the Ca(2+) ionophore A23187. In addition, we found that cells rescued from Ca(2+) ionophore-triggered apoptosis did not release calcium from their ER nor did they translocate caspase-12 from the ER to the cytoplasm. These data lend strong support to the concept that eIF4E functions as a pleiotropic regulator of cell viability and that integration of critical organelle-mediated checkpoints for apoptosis can be controlled by the cap-dependent translation apparatus.     

Automatic registration of microarray images. II. Hexagonal grid

MOTIVATION: In the first part of this paper the author presented an efficient, robust and completely automated algorithm for spot and block indexing in microarray images with rectangular grids. Although the rectangular grid is currently the most common type of grouping the probes on microarray slides, there is another microarray technology based on bundles of optical fibers where the probes are packed in hexagonal grids. The hexagonal grid provides both advantages and drawbacks over the standard rectangular packing and of course requires adaptation and/or modification of the algorithm of spot indexing presented in the first part of the paper. RESULTS: In the second part of the paper the author presents a version of the spot indexing algorithm adapted for microarray images with spots packed in hexagonal structures. The algorithm is completely automated, works with hexagonal grids of different types and with different parameters of grid spacing and rotation as well as spot sizes. It can successfully trace the local and global distortions of the grid, including non-orthogonal transformations. Similar to the algorithm from part I, it scales linearly with the grid size, the time complexity is O(M), where M is total number of grid points in hexagonal grid. The algorithm has been tested both on CCD and scanned images with spot expression rates as low as 2%. The processing time of an image with about 50 000 hex grid points was less than a second. For images with high expression rates ( approximately 90%) the registration time is even smaller, around a quarter of a second. Supplementary information: http://fleece.ucsd.edu/~vit/Registration_Supplement.pdf     

A biomechanical model of sagittal tongue bending

The human tongue is a structurally complex and extremely flexible organ. In order to better understand the mechanical basis for lingual deformations, we modeled a primitive movement of the tongue, sagittal tongue bending. We hypothesized that sagittal bending is a synergistic deformation derived from co-contraction of the longitudinalis and transversus muscles. Our model of tongue bending was based on classical bimetal strip theory, in which curvature is produced when one muscle layer contracts more so than another. Contraction was modulated via mismatched thermal expansion coefficients and temperature change (to simulate muscular contraction). Our results demonstrated that synergistic contraction produced curvature and strain results which were in better correspondence to empirical results derived from tagging MRI than were the results of contraction of the longitudinalis muscle alone. This fundamental reliance of tongue bending on the synergistic contraction of its intrinsic fibers supports the muscular hydrostat theory of tongue function.     

Spectroscopic evidence for site-specific cellular activity in the tubular gland in human intestine

The intestinal crypts contain mucus-secreting goblet cells in large numbers. In the tubular gland (crypt), the cells are generated at the bottom and end their life cycle at the top. Recently, FTIR microspectroscopy (FTIR-MC) has been applied in biology and medicine. The characterization of various cellular types using FTIR-MC and its subsequent application for the diagnosis of cancer is becoming a reality. In this report, we investigate the differential cellular activity in the normal tubular gland using FTIR-MC. Our results indicate that the absorbance for the cells in the bottom of the crypt is always higher than those in the upper portion. There are spectral pattern changes and frequency shifts for cells at the bottom and top sites of the normal crypt. Also, the comparison of a normal crypt with a malignant one has been made. This is the first spectroscopic evidence in the literature showing the difference in the cellular activity at different sites in the tubular gland. The reasons for our observations and their implications are discussed.     

Recognition of cell-specific binding of phage display derived peptides using an acoustic wave sensor

ASSLNIA, a peptide selected for murine myofibers using phage display technology, was immobilized onto an acoustic wave sensor. The sensor responded to murine and feline muscle homogenates indicating crosspieces interactions. Kidney, liver, and brain preparations produced insignificant responses.     

Nuclear import of the capsid protein of tomato yellow leaf curl virus (TYLCV) in plant and insect cells

The tomato yellow leaf curl virus (TYLCV) found in Israel is a whitefly-transmitted monopartite geminivirus. Although geminiviruses have been found in the nuclei of phloem-associated cells, the mechanism of viral invasion is poorly understood. The possible role of the TYLCV capsid protein (CP), the only known component of the viral coat, in virus transport into the host cell nucleus was investigated by monitoring its specific nuclear accumulation in plant and insect cells. CP was fused to the β-glucuronidase (GUS) reporter enzyme to assay nuclear import in petunia protoplasts, and micro-injection of purified fluorescently labeled CP was used to examine its nuclear uptake in Drosophila embryos. Both assays demonstrated that TYLCV CP is transported into plant-and insect-cell nuclei by an active process of nuclear import via a nuclear localization signal (NLS)-specific pathway. Using the GUS assay and deletion analysis, the TYLCV CP NLS sequence was identified in the amino-terminus of the protein.