Optic nerve histopathology in a case of Wolfram Syndrome: A mitochondrial pattern of axonal loss

Mitochondrial dysfunction in Wolfram Syndrome (WS) is controversial and optic neuropathy, a cardinal clinical manifestation, is poorly characterized. We here describe the histopathological features in postmortem retinas and optic nerves (ONs) from one patient with WS, testing the hypothesis that mitochondrial dysfunction underlies the pathology. Eyes and retrobulbar ONs were obtained at autopsy from a WS patient, and compared with those of a Leber hereditary optic neuropathy (LHON) patient and one healthy control. Retinas were stained with hematoxylin & eosin for general morphology and ONs were immunostained for myelin basic protein (MBP). Immunostained ONs were examined in four “quadrants”: superior, inferior, nasal, and temporal. The WS retinas displayed a severe loss of retinal ganglion cells in the macular region similar to the LHON retina, but not in the control. The WS ONs, immunostained for MBP, revealed a zone of degeneration in the temporal and inferior quadrants. This pattern was similar to that seen in the LHON ONs but not in the control. Thus, the WS patient displayed a distinct pattern of optic atrophy observed bilaterally in the temporal and inferior quadrants of the ONs. This arrangement of axonal degeneration, involving primarily the papillomacular bundle, closely resembled LHON and other mitochondrial optic neuropathies, supporting that mitochondrial dysfunction underlies its pathogenesis.     

SOX2 Regulates YAP1 to Maintain Stemness and Determine Cell Fate in the Osteo-Adipo Lineage

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In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)₃]²⁺ (bpy = bipyridine), onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.     

Expression of proinflammatory cytokines by human mesenchymal stem cells in response to cyclic tensile strain

Mesenchymal stem cells produce proinflammatory cytokines during their normal growth. Direct or indirect regulation of bone resorption by these cytokines has been reported. However, the effects of osteogenic conditions—chemical and/or mechanical—utilized during in vitro bone tissue engineering on expression of cytokines by hMSCs have not been studied. In this study, we investigated the effects of cyclic tensile strain, culture medium (with and without dexamethasone), and culture duration on the expression of tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and interleukin‐8 (IL‐8) by bone marrow derived human mesenchymal stem cells (hMSCs). Human MSCs seeded in three‐dimensional Type I collagen matrices were subjected to 0%, 10%, and 12% uniaxial cyclic tensile strains at 1 Hz for 4 h/day for 7 and 14 days in complete growth or dexamethasone‐containing osteogenic medium. Viability of hMSCs was maintained irrespective of strain level and media conditions. Expression of either TNF‐α or IL‐1β was not observed in hMSCs under any of the conditions investigated in this study. Expression of IL‐6 was dependent on culture medium. An increase in IL‐6 expression was caused by both 10% and 12% strain levels. Both 10% and 12% strain levels caused an increase in IL‐8 production by hMSCs that was dependent on the presence of dexamethasone. IL‐6 and IL‐8 expressions by hMSCs were induced by cyclic tensile strain and osteogenic differentiating media, indicating that IL‐6 and IL‐8 may be functioning as autocrine signals during osteogenic differentiation of hMSCs. J. Cell. Physiol. 219: 77–83, 2009. © 2008 Wiley‐Liss, Inc.     

Ultrafast Mid-IR Laser Scalpel: Protein Signals of the Fundamental Limits to Minimally Invasive Surgery

Lasers have in principle the capability to cut at the level of a single cell, the fundamental limit to minimally invasive procedures and restructuring biological tissues. To date, this limit has not been achieved due to collateral damage on the macroscale that arises from thermal and shock wave induced collateral damage of surrounding tissue. Here, we report on a novel concept using a specifically designed Picosecond IR Laser (PIRL) that selectively energizes water molecules in the tissue to drive ablation or cutting process faster than thermal exchange of energy and shock wave propagation, without plasma formation or ionizing radiation effects. The targeted laser process imparts the least amount of energy in the remaining tissue without any of the deleterious photochemical or photothermal effects that accompanies other laser wavelengths and pulse parameters. Full thickness incisional and excisional wounds were generated in CD1 mice using the Picosecond IR Laser, a conventional surgical laser (DELight Er:YAG) or mechanical surgical tools. Transmission and scanning electron microscopy showed that the PIRL laser produced minimal tissue ablation with less damage of surrounding tissues than wounds formed using the other modalities. The width of scars formed by wounds made by the PIRL laser were half that of the scars produced using either a conventional surgical laser or a scalpel. Aniline blue staining showed higher levels of collagen in the early stage of the wounds produced using the PIRL laser, suggesting that these wounds mature faster. There were more viable cells extracted from skin using the PIRL laser, suggesting less cellular damage. β-catenin and TGF-β signalling, which are activated during the proliferative phase of wound healing, and whose level of activation correlates with the size of wounds was lower in wounds generated by the PIRL system. Wounds created with the PIRL systsem also showed a lower rate of cell proliferation. Direct comparison of wound healing responses to a conventional surgical laser, and standard mechanical instruments shows far less damage and near absence of scar formation by using PIRL laser. This new laser source appears to have achieved the long held promise of lasers in minimally invasive surgery.     

Development of a high-throughput IMS-IMS-MS approach for analyzing mixtures of biomolecules

A high-throughput approach for biomolecule analysis is demonstrated for a mixture of peptides from tryptic digest of four proteins as well as a tryptic digests of human plasma. In this method a chip based electrospray autosampler coupled to a hybrid ion mobility (IMS) mass spectrometer (MS) is utilized to achieve rapid sample analysis. This high-throughput measurement is realized by exploiting the direct infusion capability of the chip based electrospray with its rapid sample manipulating capability as well as a high sensitive IMS-MS with a recently developed IMS-IMS separation technique that can be multiplexed to provide greater throughput. From replicate IMS-MS runs of known mixtures, the average uncertainty of peak intensities is determined to be +/-7% (relative standard deviation), and a detection limit in the low attomole range is established. The method is illustrated by analyzing 124 human plasma protein samples in duplicate, a measurement that required 16.5 h. Current limitations as well as implications of the high-throughput approach for complex biological sample analysis are discussed.