Biochemical basis for depressed serum retinol levels in transthyretin-deficient mice

Transthyretin (TTR) acts physiologically in the transport of retinol in the circulation. We previously reported the generation and partial characterization of TTR-deficient (TTR(-)) mice. TTR(-) mice have very low circulating levels of retinol and its specific transport protein, retinol-binding protein (RBP). We have examined the biochemical basis for the low plasma retinol-RBP levels. Cultured primary hepatocytes isolated from wild type (WT) and TTR(-) mice accumulated RBP in their media to an identical degree, suggesting that RBP was being secreted from the hepatocytes at the same rate. In vivo experiments support this conclusion. For the first 11 h after complete nephrectomy, the levels retinol and RBP rose in the circulations of WT and TTR(-) mice at nearly identical rates. However, human retinol-RBP injected intravenously was more rapidly cleared from the circulation (t(12) = 0.5 h for TTR(-) versus t(12) >6 h for WT) and accumulated faster in the kidneys of TTR(-) compared with WT mice. The rate of infiltration of the retinol-RBP complex from the circulation to tissue interstitial fluids was identical in both strains. Taken together, these data indicate that low circulating retinol-RBP levels in TTR(-) mice arise from increased renal filtration of the retinol-RBP complex.     

Good,better, best? The effects of polarization on photobiomodulation therapy

Photobiomodulation therapy (PBMT) is a widely adopted form of phototherapy used to treat many chronic conditions that effect the population at large. The exact physiological mechanisms of PBMT remain unsolved; however, the prevailing theory centres on changes in mitochondrial function. There are many irradiation parameters to consider when investigating PBMT, one of which is the state of polarization. There is some evidence to show that polarization of red and near‐infrared light may promote different and/or increased biological activity when compared to otherwise identical non‐polarized light. These enhanced cellular effects may also be present when the polarized light is applied linear to the tissue direction. Herein, we synthesize the current experimental and clinical evidence pertaining to polarized photobiomodulation therapy; ultimately, to better inform future research into this area of phototherapy.     

The Proteomic Landscape of Centromeric Chromatin Reveals an Essential Role for the Ctf19CCAN Complex in Meiotic Kinetochore Assembly

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Synthesis and characterization of a DNA complementary to Xenopus laevis albumin mRNA

Summary Albumin complementary DNA (cDNA) was transcribed from purified albumin mRNA from the liver of Xenopus laevis. The resultant cDNA was an almost full length copy as defined by denaturing gel electrophoresis; was hybridized specifically to albumin mRNA with pseudo-first-order reaction kinetics and the mRNA · cDNA hybrid exhibited a sharp melting profile with a Tm of 83 °C. The identity of the cDNA was confirmed by gel electrophoresis following hybridization-arrested translation.