The intrinsic stiffness of human trabecular meshwork cells increases with senescence.

Dysfunction of the human trabecular meshwork (HTM) plays a central role in the age-associated disease glaucoma, a leading cause of irreversible blindness. The etiology remains poorly understood but cellular senescence, increased stiffness of the tissue, and the expression of Wnt antagonists such as secreted frizzled related protein-1 (SFRP1) have been implicated. However, it is not known if senescence is causally linked to either stiffness or SFRP1 expression. In this study, we utilized in vitro HTM senescence to determine the effect on cellular stiffening and SFRP1 expression. Stiffness of cultured cells was measured using atomic force microscopy and the morphology of the cytoskeleton was determined using immunofluorescent analysis. SFRP1 expression was measured using qPCR and immunofluorescent analysis. Senescent cell stiffness increased 1.88±0.14 or 2.57±0.14 fold in the presence or absence of serum, respectively. This was accompanied by increased vimentin expression, stress fiber formation, and SFRP1 expression. In aggregate, these data demonstrate that senescence may be a causal factor in HTM stiffening and elevated SFRP1 expression, and contribute towards disease progression. These findings provide insight into the etiology of glaucoma and, more broadly, suggest a causal link between senescence and altered tissue biomechanics in aging-associated diseases

CTQ 414: A New Gravitational Lens

We report the discovery and ground based observations of the new gravitational lens CTQ 414. The source quasar lies at a redshift of z = 1.29 with a B magnitude of 17.6. Ground based optical imaging reveals two point sources separated by 1.2 arcsec with a magnitude difference of roughly 1 mag. Subtraction of two stellar point spread functions from images obtained in subarcsecond seeing consistently leaves behind a faint, residual object. Fits for two point sources plus an extended object places the fainter object collinear with the two brighter components. Subsequent HST/NICMOS observations have confirmed the identification of the fainter object as the lensing galaxy. VLA observations at 8.46 GHz reveal that all components of the lensing system are radio quiet down to the 0.2 mJy flux level.Comment: Latex, 18 pages including 2 ps figures; accepted for publication in A

CTQ 839: Candidate for the Smallest Projected Separation Binary Quasar

We report the discovery of the new double quasar CTQ 839. This B = 18.3, radio quiet quasar pair is separated by 2.1" in BRIH filters with magnitude differences of delta m_B = 2.5, delta m_R = delta m_I = 1.9, and delta m_H = 2.3. Spectral observations reveal both components to be z = 2.24 quasars, with relative redshifts that agree at the 100 km/s level, but exhibit pronounced differences in the equivalent widths of related emission features, as well as an enhancement of blue continuum flux in the brighter component longward of the Ly alpha emission feature. In general, similar redshift double quasars can be the result of a physical binary pair, or a single quasar multiply imaged by gravitational lensing. Empirical PSF subtraction of R and H band images of CTQ 839 reveal no indication of a lensing galaxy, and place a detection limit of R = 22.5 and H = 17.4 for a third component in the system. For an Einstein-de Sitter cosmology and SIS model, the R band detection limit constrains the characteristics of any lensing galaxy to z_lens >= 1 with a corresponding luminosity of L >~ 5 L_*, while an analysis based on the redshift probability distribution for the lensing galaxy argues against the existence of a z_lens >~ 1 lens at the 2 sigma level. A similar analysis for a Lambda dominated cosmology, however, does not significantly constrain the existence of any lensing galaxy. The broadband flux differences, spectral dissimilarities, and failure to detect a lensing galaxy make the lensing hypothesis for CTQ 839 unlikely. The similar redshifts of the two components would then argue for a physical quasar binary. At a projected separation of 8.3/h kpc (Omega_matter = 1), CTQ 839 would be the smallest projected separation binary quasar currently known.Comment: Latex, 23 pages including 5 ps figures; accepted for publication in A

Biomechanical, ultrastructural, and electrophysiological characterization of the non-human primate experimental glaucoma model.

Laser-induced experimental glaucoma (ExGl) in non-human primates (NHPs) is a common animal model for ocular drug development. While many features of human hypertensive glaucoma are replicated in this model, structural and functional changes in the unlasered portions of trabecular meshwork (TM) of laser-treated primate eyes are understudied. We studied NHPs with ExGl of several years duration. As expected, ExGl eyes exhibited selective reductions of the retinal nerve fiber layer that correlate with electrophysiologic measures documenting a link between morphologic and elctrophysiologic endpoints. Softening of unlasered TM in ExGl eyes compared to untreated controls was observed. The degree of TM softening was consistent, regardless of pre-mortem clinical findings including severity of IOP elevation, retinal nerve fiber layer thinning, or electrodiagnostic findings. Importantly, this softening is contrary to TM stiffening reported in glaucomatous human eyes. Furthermore, microscopic analysis of unlasered TM from eyes with ExGl demonstrated TM thinning with collapse of Schlemm's canal; and proteomic analysis confirmed downregulation of metabolic and structural proteins. These data demonstrate unexpected and compensatory changes involving the TM in the NHP model of ExGl. The data suggest that compensatory mechanisms exist in normal animals and respond to elevated IOP through softening of the meshwork to increase outflow

Low-Cost Compact Diffuse Speckle Contrast Flowmeter Using Small Laser Diode and Bare Charge-Coupled-Device

We report a low-cost compact diffuse speckle contrast flowmeter (DSCF) consisting of a small laser diode and a bare charge-coupled-device (CCD) chip, which can be used for contact measurements of blood flow variations in relatively deep tissues (up to ∼8  mm). Measurements of large flow variations by the contact DSCF probe are compared to a noncontact CCD-based diffuse speckle contrast spectroscopy and a standard contact diffuse correlation spectroscopy in tissue phantoms and a human forearm. Bland–Altman analysis shows no significant bias with good limits of agreement among these measurements: 96.5% ± 2.2% (94.4% to 100.0%) in phantom experiments and 92.8% in the forearm test. The relatively lower limit of agreement observed in the in vivo measurements (92.8%) is likely due to heterogeneous reactive responses of blood flow in different regions/volumes of the forearm tissues measured by different probes. The low-cost compact DSCF device holds great potential to be broadly used for continuous and longitudinal monitoring of blood flow alterations in ischemic/hypoxic tissues, which are usually associated with various vascular diseases

PMN J1632-0033: A new gravitationally lensed quasar

We report the discovery of a gravitationally lensed quasar resulting from our survey for lenses in the southern sky. Radio images of PMN J1632-0033 with the VLA and ATCA exhibit two compact, flat-spectrum components with separation 1.47" and flux density ratio 13.2. Images with the HST reveal the optical counterparts to the radio components and also the lens galaxy. An optical spectrum of the bright component, obtained with the first Magellan telescope, reveals quasar emission lines at redshift 3.42. Deeper radio images with MERLIN and the VLBA reveal a faint third radio component located near the center of the lens galaxy, which is either a third image of the background quasar or faint emission from the lens galaxy.Comment: 21 pp., including 4 figures; thoroughly revised in light of new MERLIN/HST data; accepted for publication in A

PMN J1838-3427: A new gravitationally lensed quasar

We report the discovery of a new double-image quasar that was found during a search for gravitational lenses in the southern sky. Radio source PMN J1838-3427 is composed of two flat-spectrum components with separation 1", flux density ratio 14:1 and matching spectral indices, in VLA and VLBA images. Ground-based BRI images show the optical counterpart (total I=18.6) is also double with the same separation and position angle as the radio components. An HST/WFPC2 image reveals the lens galaxy. The optical flux ratio (27:1) is higher than the radio value probably due to differential extinction of the components by the lens galaxy. An optical spectrum of the bright component contains quasar emission lines at z=2.78 and several absorption features, including prominent Ly-alpha absorption. The lens galaxy redshift could not be measured but is estimated to be z=0.36 +/- 0.08. The image configuration is consistent with the simplest plausible models for the lens potential. The flat radio spectrum and observed variability of PMN J1838-3427 suggest the time delay between flux variations of the components is measurable, and could thus provide an independent measurement of H_0.Comment: 23 pages, incl. 6 figures, to appear in A.J.; replaced with accepted version; minor changes to text, improved figure

Specific inhibition of complement activation significantly ameliorates autoimmune blistering disease in mice

Epidermolysis bullosa acquisita (EBA) is an antibody-mediated blistering skin disease associated with tissue-bound and circulating autoantibodies to type VII collagen (COL7). Transfer of antibodies against COL7 into mice results in a subepidermal blistering phenotype, strictly depending on the complement component C5. Further, activation predominantly by the alternative pathway is required to induce experimental EBA, as blistering was delayed and significantly ameliorated only in factor B−/− mice. However, C5 deficiency not only blocked the activation of terminal complement components and assembly of the membrane attack complex (MAC) but also eliminated the formation of C5a. Therefore, in the present study, we first aimed to elucidate which molecules downstream of C5 are relevant for blister formation in this EBA model and could be subsequently pharmaceutically targeted. For this purpose, we injected mice deficient in C5a receptor 1 (C5aR1) or C6 with antibodies to murine COL7. Importantly, C5ar1−/− mice were significantly protected from experimental EBA, demonstrating that C5a–C5aR1 interactions are critical intermediates linking pathogenic antibodies to tissue damage in this experimental model of EBA. By contrast, C6−/− mice developed widespread blistering disease, suggesting that MAC is dispensable for blister formation in this model. In further experiments, we tested the therapeutic potential of inhibitors of complement components which were identified to play a key role in this experimental model. Complement components C5, factor B (fB), and C5aR1 were specifically targeted using complement inhibitors both prophylactically and in mice that had already developed disease. All complement inhibitors led to a significant improvement of the blistering phenotype when injected shortly before anti-COL7 antibodies. To simulate a therapeutic intervention, anti-fB treatment was first administered in full-blown EBA (day 5) and induced significant amelioration only in the final phase of disease evolution, suggesting that early intervention in disease development may be necessary to achieve higher efficacy. Anti-C5 treatment in incipient EBA (day 2) significantly ameliorated disease during the whole experiment. This finding is therapeutically relevant, since the humanized anti-C5 antibody eculizumab is already successfully used in patients. In conclusion, in this study, we have identified promising candidate molecules for complement-directed therapeutic intervention in EBA and similar autoantibody-mediated diseases