Nanomembrane-Based, Thermal-Transport Biosensor for Living Cells.

Knowledge of materials' thermal-transport properties, conductivity and diffusivity, is crucial for several applications within areas of biology, material science and engineering. Specifically, a microsized, flexible, biologically integrated thermal transport sensor is beneficial to a plethora of applications, ranging across plants physiological ecology and thermal imaging and treatment of cancerous cells, to thermal dissipation in flexible semiconductors and thermoelectrics. Living cells pose extra challenges, due to their small volumes and irregular curvilinear shapes. Here a novel approach of simultaneously measuring thermal conductivity and diffusivity of different materials and its applicability to single cells is demonstrated. This technique is based on increasing phonon-boundary-scattering rate in nanomembranes, having extremely low flexural rigidities, to induce a considerable spectral dependence of the bandgap-emission over excitation-laser intensity. It is demonstrated that once in contact with organic or inorganic materials, the nanomembranes' emission spectrally shift based on the material's thermal diffusivity and conductivity. This NM-based technique is further applied to differentiate between different types and subtypes of cancer cells, based on their thermal-transport properties. It is anticipated that this novel technique to enable an efficient single-cell thermal targeting, allow better modeling of cellular thermal distribution and enable novel diagnostic techniques based on variations of single-cell thermal-transport properties.

Angle closure glaucoma and lens subluxation secondary to eye rubbing in a patient with mycosis fungoides.

We report an unusual case of angle closure glaucoma in a patient with the skin lymphoma mycosis fungoides. Constant eye rubbing led to bilateral lens subluxation and uncontrolled intraocular pressure.

Matrix bound SFD mutant TIMP-3 is more stable than wild type TIMP-3.

BACKGROUND: Sorsby's fundus dystrophy (SFD) is a degenerative retinopathy characterised by accumulation of mutant TIMP-3 protein in Bruch's membrane. AIM: To compare the stability of matrix bound SFD mutant TIMP-3s with wild type TIMP-3. METHODS: COS-7 cells were transfected with plasmids containing wild type, Ser 181, Gly-167, Ser-156, and Tyr-168 TIMP-3 cDNA. The cells and their matrices were subsequently harvested and homogenised. After measuring the bound wild type and SFD mutant TIMP-3 concentrations by ELISA, aliquots of the homogenates were heated to 100 degrees C. The rates of denaturation of the TIMP proteins at this temperature were monitored by reverse zymography. RESULTS: Over a period of 24 h at 100 degrees C the biological activity of both wild type and SFD mutant TIMP-3 was lost. Over a period of 6 h at this temperature the biological activity of the SFD mutant TIMP-3s was fully retained whereas that of the wild type TIMP-3 was lost. CONCLUSION: Matrix bound SFD mutant TIMP-3s are thermodynamically more stable than wild type. This may explain why SFD starts earlier in life than age related macular degeneration.

Full-thickness macular hole: a rare complication of Borrelia burgdorferi neuroretinitis.

Borrelia burgdorferi is a known infective cause of neuroretinitis. We present a case of B burgdorferi neuroretinitis complicated by macular hole in a 22-year-old man. The neuroretinitis was managed with early high-dose intravenous corticosteroid and oral antibiotic. The macular hole was managed with macular hole surgery after intraocular inflammation had resolved.

Sorsby's fundus dystrophy mutant tissue inhibitors of metalloproteinase-3 induce apoptosis of retinal pigment epithelial and MCF-7 cells.

C-terminal domain tissue inhibitor of metalloproteinases-3 (TIMP-3) mutations cause the rare hereditary blindness Sorsby's fundus dystrophy (SFD), which involves loss of retinal pigment epithelial (RPE) cells. Since wild-type TIMP-3 causes apoptosis, we investigated whether SFD TIMP-3 might kill RPE and other cells. Plasmid-mediated overexpression of Ser-156, Gly-167, Tyr-168 and Ser-181 SFD mutant TIMP-3 decreased RPE viability to 22+/-8, 20+/-6, 32+/-5, 30+/-12% (SFD mutants all P<0.01 versus wild-type 50+/-8%) and similarly increased propidium iodide staining and in situ end labelling. Adenovirus-mediated overexpression of the Gly-167 mutant also caused RPE apoptosis dose-dependently. Apoptosis of RPE cells might therefore contribute to the pathology of SFD.

Adenovirus mediated gene delivery of tissue inhibitor of metalloproteinases-3 induces death in retinal pigment epithelial cells.

BACKGROUND: Sorsby's fundus dystrophy (SFD) and age related macular degeneration (ARMD) are retinal diseases associated with a high level of accumulation of mutant and wild type TIMP-3, respectively, in Bruch's membrane. The pathogenic role of TIMP-3 in these diseases is uncertain, but causative mutations have been identified in the TIMP-3 gene of patients with SFD. Recent reports that TIMP-3 causes apoptosis in certain cell types and not in others prompted the authors to investigate whether TIMP-3 causes apoptosis in cultured retinal pigment epithelium (RPE) cells. METHODS: RPE and MCF-7 cells (as a positive control) were initially infected with replication deficient adenovirus, to overexpress beta-galactosidase (RAdLacZ) or TIMP-3 (RAdTIMP-3). TIMP-3 was detected by western blotting and ELISA. Cell viability was defined by cell counts. ISEL was used to investigate the mechanism of cell death. RESULTS: Cultured RPE cells produced small quantities of endogenous TIMP-3 and remained viable. However, overexpression of TIMP-3 caused a dose related death of RPE cells. The mechanism of cell death was apoptosis. CONCLUSION: The previously unreported finding of TIMP-3 induced apoptosis of RPE cells may account for some of the early features seen in SFD and ARMD.

Recessive mutations in DGKE cause atypical hemolytic-uremic syndrome.

Pathologic thrombosis is a major cause of mortality. Hemolytic-uremic syndrome (HUS) features episodes of small-vessel thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia and renal failure. Atypical HUS (aHUS) can result from genetic or autoimmune factors that lead to pathologic complement cascade activation. Using exome sequencing, we identified recessive mutations in DGKE (encoding diacylglycerol kinase ɛ) that co-segregated with aHUS in nine unrelated kindreds, defining a distinctive Mendelian disease. Affected individuals present with aHUS before age 1 year, have persistent hypertension, hematuria and proteinuria (sometimes in the nephrotic range), and develop chronic kidney disease with age. DGKE is found in endothelium, platelets and podocytes. Arachidonic acid-containing diacylglycerols (DAG) activate protein kinase C (PKC), which promotes thrombosis, and DGKE normally inactivates DAG signaling. We infer that loss of DGKE function results in a prothrombotic state. These findings identify a new mechanism of pathologic thrombosis and kidney failure and have immediate implications for treating individuals with aHUS.

Inflammatory choroidal neovascular membrane in posterior uveitis-pathogenesis and treatment.

Choroidal neovascular membrane (CNVM) formation is a well-documented sight-threatening complication of posterior segment intraocular inflammation (PSII). The aim of this article is to review the basic and clinical science literature on the pathogenesis of CNVM formation in PSII and to present results of a case series. We searched the literature using the mesh terms- inflammation, CNVM, age-related macular degeneration, immunosuppression, photodynamic therapy, steroids, vascular endothelial growth factors and posterior uveitis. Additionally, we evaluated the visual outcome of and clinical response to our standard treatment protocol involving a combination treatment for young patients with inflammatory CNVM. The development of CNVM in PSII is promulgated by infiltrating myeloid cells as well as choroidal and retinal myeloid cell activation, subsequent vascular endothelial growth factors, cytokine and chemokine production and complement activation acting in consort to mediate angiogenic responses. No clear standard of care currently exists for the treatment of inflammatory CNVM and various combinations have been tried. Using our combination treatment, visual acuity improved in four, stabilized in one and worsened in four patients. Though significant advances have occurred in the understanding of the pathogenesis and management of this condition, optimizing therapeutic regimens will require further well-constructed prospective cohort series.

Bevacizumab for neovascular age related macular degeneration (ABC Trial): multicentre randomised double masked study.

OBJECTIVES: To evaluate the efficacy and safety of intravitreous bevacizumab injections for the treatment of neovascular age related macular degeneration. DESIGN: Prospective, double masked, multicentre, randomised controlled trial. SETTING: Three ophthalmology centres in the United Kingdom. PARTICIPANTS: 131 patients (mean age 81) with wet age related macular degeneration randomised 1:1 to intervention or control. INTERVENTIONS: Intravitreous bevacizumab (1.25 mg, three loading injections at six week intervals followed by further treatment if required at six week intervals) or standard treatment available at the start of the trial (photodynamic treatment with verteporfin for predominantly classic type neovascular age related macular degeneration, or intravitreal pegaptanib or sham treatment for occult or minimally classic type neovascular age related macular degeneration). PRIMARY OUTCOME: proportion of patients gaining >or=15 letters of visual acuity at one year (54 weeks). SECONDARY OUTCOMES: proportion of patients with stable vision and mean change in visual acuity. RESULTS: Of the 131 patients enrolled in the trial, five patients did not complete the study because of adverse events, loss to follow-up, or death. In the bevacizumab group, 21 (32%) patients gained 15 or more letters from baseline visual acuity compared with two (3%) in the standard care group (P<0.001); the estimated adjusted odds ratio was 18.1 (95% confidence interval 3.6 to 91.2) and the number needed to treat was 4 (3 to 6). In addition, the proportion of patients who lost fewer than 15 letters of visual acuity from baseline was significantly greater among those receiving bevacizumab treatment (91% (59) v 67% (44) in standard care group; P<0.001). Mean visual acuity increased by 7.0 letters in the bevacizumab group with a median of seven injections compared with a decrease of 9.4 letters in the standard care group (P<0.001), and the initial improvement at week 18 (plus 6.6 letters) was sustained to week 54. Among 65 patients treated with bevacizumab, there were no cases of endophthalmitis or serious uveitis related to the intervention. All end points with respect to visual acuity in the study eye at 54 weeks favoured bevacizumab treatment over standard care. CONCLUSIONS: Bevacizumab 1.25 mg intavitreous injections given as part of a six weekly variable retreatment regimen is superior to standard care (pegaptanib sodium, verteporfin, sham), with low rates of serious ocular adverse events. Treatment improved visual acuity on average at 54 weeks. Trial registration number Current controlled trials ISRCTN83325075.

Changes in the balance of the tissue inhibitor of matrix metalloproteinases (TIMPs)-1 and -3 may promote keratocyte apoptosis in keratoconus.

Keratoconus is a disease in which the central cornea becomes thinned. This could result from corneal stromal cell apoptosis or be induced or perpetuated by the activation of matrix degrading enzymes, particularly members of the matrix metalloproteinase (MMP) family. In some circumstances, the MMP inhibitors TIMP-1 and TIMP-3 exhibit anti-apoptotic and pro-apoptotic properties, respectively. Because they potentially influence keratoconus progression, the effects of TIMP-1 and TIMP-3 on stromal cell viability were investigated. The TIMP-1 and TIMP-3 proteins were over-expressed in cultured corneal stromal cells by using the adenoviral vectors RAdTIMP-1 and RAdTIMP-3 and quantified by enzyme-linked immunosorbant assay (ELISA). Apoptotic cells were detected by TUNEL and caspase-3 activity. The anti-apoptotic effects of TIMP-1 were investigated by co-infecting it with RAdTIMP-1 and RAdTIMP-3 and by adding TIMP-1 protein to stromal cell cultures prior to infecting them with RAdTIMP-3. Immunohistochemistry was used to localise and determine relative numbers of apoptotic and TIMP producing stromal cells in sections of normal and keratoconic corneas. The results showed that over-expression of TIMP-3 induced apoptosis in corneal stromal cell cultures. Up-regulated TIMP-1 production or the addition of exogenous TIMP-1 protein prevented stromal cell overgrowth, changed stromal cell morphology and reduced the extent of TIMP-3 induced apoptosis. Localised relative concentrations of TIMP-1/TIMP-3 could thus determine whether these cells remain viable or become apoptotic. This may be relevant to the keratoconic condition since significantly more apoptotic cells were identified in the anterior stroma of keratoconic corneas than normal corneas and the majority of theTIMP-1 and TIMP-3 producing stromal cells were also located in this region.

Subperiosteal orbital hemorrhage following self-strangulation.

Subperiosteal orbital hematomas are uncommon. The delayed presentation of such an event is described in an anticoagulated patient who attempted self-strangulation. Despite the initial presence of a relative afferent pupillary defect, excellent visual recovery occurred, demonstrating the importance of prompt recognition and treatment. The causes, mechanism of visual loss, radiographic diagnosis, and treatment of subperiosteal hemorrhages are discussed.