Assessment of conjunctival, episcleral and scleral thickness in healthy individuals using anterior segment optical coherence tomography.

PURPOSE: To determine the thickness of the conjunctiva, episclera and sclera in healthy individuals using anterior segment optical coherence tomography (AS-OCT). METHODS: We prospectively included 107 healthy individuals of different age groups (18-39 years, 40-54 years, 55-69 years and ≥70 years). For each eye, AS-OCT scans of four quadrants (temporal, nasal, superior and inferior) were acquired. The thickness of the conjunctiva, episclera and sclera was measured for each scan. In addition, the axial length of both eyes was measured, and general characteristics, including smoking, allergies and contact lens use, were collected. RESULTS: The mean conjunctival thickness was significantly different between the nasal and superior quadrants (87 ± 30 µm vs. 77 ± 16 µm; p < 0.001), as well as the superior and inferior quadrants (77 ± 16 µm vs. 86 ± 19 µm; p = 0.001). The mean episcleral thickness was larger in the superior (174 ± 54 µm) and inferior (141 ± 43 µm) quadrants, compared to the nasal (83 ± 38 µm) and temporal quadrants (90 ± 44 µm). The mean scleral thickness of the inferior quadrant was the largest (596 ± 64 µm), followed by the nasal (567 ± 76 µm), temporal (516 ± 67 µm) and superior (467 ± 52 µm) quadrants (all p < 0.001). The averaged scleral thickness increased 0.96 µm per age year (0.41-1.47 µm, p < 0.001). CONCLUSIONS: This study provides an assessment of the thickness of scleral and adjacent superficial layers in healthy individuals determined on AS-OCT, which could enable future research into the use of AS-OCT in diseases affecting the anterior eye wall.

Tritium Beta Spectrum Measurement and Neutrino Mass Limit from Cyclotron Radiation Emission Spectroscopy.

The absolute scale of the neutrino mass plays a critical role in physics at every scale, from the subatomic to the cosmological. Measurements of the tritium end-point spectrum have provided the most precise direct limit on the neutrino mass scale. In this Letter, we present advances by Project 8 to the cyclotron radiation emission spectroscopy (CRES) technique culminating in the first frequency-based neutrino mass limit. With only a cm^{3}-scale physical detection volume, a limit of m_{ß}<155 eV/c^{2} (152 eV/c^{2}) is extracted from the background-free measurement of the continuous tritium beta spectrum in a Bayesian (frequentist) analysis. Using ^{83m}Kr calibration data, a resolution of 1.66±0.19 eV (FWHM) is measured, the detector response model is validated, and the efficiency is characterized over the multi-keV tritium analysis window. These measurements establish the potential of CRES for a high-sensitivity next-generation direct neutrino mass experiment featuring low background and high resolution.

Predicting anoxia in the wet and dry periods of tropical semiarid reservoirs.

The dissolved oxygen (DO) level in the hypolimnion of lakes and reservoirs can reach anoxic conditions, which favor the release of phosphorus from the sediment bed to the water column. However, to estimate nutrient release from sediment is extremely important to quantify the duration of anoxia. In low latitude regions, the water-sediment layer is warmer than in temperate regions and eutrophication is usually more severe, potentially accelerating oxygen depletion and extending the anoxia period. Considering that the available equations to quantify the duration of anoxia were developed for temperate lakes, there is a need to effectively quantify this period in lakes and reservoirs located in other climate regions, such as the semiarid. In this study, the dynamics of thermal stratification was analyzed as a function of the Relative Water Column Stability coefficient (RWCS) and then correlated with DO dynamics for nineteen tropical semiarid reservoirs. RWCS values were higher during the rainy season, when anoxia duration was longer and the hypolimnion was thicker with respect to total water depth. Then, two new equations for quantification of anoxia duration, based on the equation originally developed for temperate climate, were adapted for the wet and dry seasons of the tropical semiarid region. The results showed that the proposed equations presented a better performance compared to the original one, which tends to underestimate anoxia in tropical semiarid reservoirs. This work intended to provide simple and locally adjusted tools to better quantify anoxic events and support the water quality and internal phosphorus load modeling for tropical semiarid reservoirs.

Bactericidal and fungicidal capacity of Ag2O/Ag nanoparticles synthesized with Aloe vera extract.

This research aims to provide an alternative eco-friendly way to obtain silver species and assess their bactericidal activity. This study reports the synthesis of Ag2O nanoparticles and Ag nanoparticles reduced with a green synthesis method, using a low-cost and commercial Aloe vera extract. The crystalline phases of Ag and Ag2O nanoparticles were analyzed by X-ray diffraction. The oxidation states for both species were determined by X-ray photoelectron spectroscopy. The optical properties of the material were studied through optical absorption, which resulted in well-defined band centered at 545 nm. This result is attributed to the morphology and size of the silver nanoparticles. In addition, antibacterial tests were performed on AgNPs biosynthesized with A. vera with the Kirby-Bauer protocol on Gram-negative and Gram-positive bacteria Escherichia coli and Staphylococcus aureaus, respectively. Moreover, antifungal tests were performed with various species from Candida.

G-quadruplex dynamics contribute to regulation of mitochondrial gene expression.

Single-stranded DNA or RNA sequences rich in guanine (G) can adopt non-canonical structures known as G-quadruplexes (G4). Mitochondrial DNA (mtDNA) sequences that are predicted to form G4 are enriched on the heavy-strand and have been associated with formation of deletion breakpoints. Increasing evidence supports the ability of mtDNA to form G4 in cancer cells; however, the functional roles of G4 structures in regulating mitochondrial nucleic acid homeostasis in non-cancerous cells remain unclear. Here, we demonstrate by live cell imaging that the G4-ligand RHPS4 localizes primarily to mitochondria at low doses. We find that low doses of RHPS4 do not induce a nuclear DNA damage response but do cause an acute inhibition of mitochondrial transcript elongation, leading to respiratory complex depletion. We also observe that RHPS4 interferes with mtDNA levels or synthesis both in cells and isolated mitochondria. Importantly, a mtDNA variant that increases G4 stability and anti-parallel G4-forming character shows a stronger respiratory defect in response to RHPS4, supporting the conclusion that mitochondrial sensitivity to RHPS4 is G4-mediated. Taken together, our results indicate a direct role for G4 perturbation in mitochondrial genome replication, transcription processivity, and respiratory function in normal cells.

NADPH oxidase 2 inhibitors CPP11G and CPP11H attenuate endothelial cell inflammation & vessel dysfunction and restore mouse hind-limb flow.

First described as essential to the phagocytic activity of leukocytes, Nox2-derived ROS have emerged as mediators of a range of cellular and tissue responses across species from salubrious to deleterious consequences. Knowledge of their role in inflammation is limited, however. We postulated that TNFα-induced endothelial reactive oxygen species (ROS) generation and pro-inflammatory signaling would be ameliorated by targeting Nox2. Herein, we in silico-modelled two first-in-class Nox2 inhibitors developed in our laboratory, explored their cellular mechanism of action and tested their efficacy in in vitro and mouse in vivo models of inflammation. Our data show that these inhibitors (CPP11G and CPP11H) disrupted canonical Nox2 organizing factor, p47phox, translocation to Nox2 in the plasma membrane; and abolished ROS production, markedly attenuated stress-responsive MAPK signaling and downstream AP-1 and NFκB nuclear translocation in human cells. Consequently, cell adhesion molecule expression and monocyte adherence were significantly inhibited by both inhibitors. In vivo, TNFα-induced ROS and inflammation were ameliorated by targeted Nox2 inhibition, which, in turn, improved hind-limb blood flow. These studies identify a proximal role for Nox2 in propagated inflammatory signaling and support therapeutic value of Nox2 inhibitors in inflammatory disease.

Exploring inter-organ crosstalk to uncover mechanisms that regulate ß-cell function and mass.

Impaired ß-cell function and insufficient ß-cell mass compensation are twin pathogenic features that underlie type 2 diabetes (T2D). Current therapeutic strategies continue to evolve to improve treatment outcomes in different ethnic populations and include approaches to counter insulin resistance and improve ß-cell function. Although the effects of insulin secretion on metabolic organs such as liver, skeletal muscle and adipose is directly relevant for improving glucose uptake and reduce hyperglycemia, the ability of pancreatic ß-cells to crosstalk with multiple non-metabolic tissues is providing novel insights into potential opportunities for improving ß-cell function and/or mass that could have beneficial effects in patients with diabetes. For example, the role of the gastrointestinal system in the regulation of ß-cell biology is well recognized and has been exploited clinically to develop incretin-related antidiabetic agents. The microbiome and the immune system are emerging as important players in regulating ß-cell function and mass. The rich innervation of islet cells indicates it is a prime organ for regulation by the nervous system. In this review, we discuss the potential implications of signals from these organ systems as well as those from bone, placenta, kidney, thyroid, endothelial cells, reproductive organs and adrenal and pituitary glands that can directly impact ß-cell biology. An added layer of complexity is the limited data regarding the relative relevance of one or more of these systems in different ethnic populations. It is evident that better understanding of this paradigm would provide clues to enhance ß-cell function and/or mass in vivo in the long-term goal of treating or curing patients with diabetes.

Circadian control of ß-cell function and stress responses.

Circadian disruption is the bane of modern existence and its deleterious effects on health; in particular, diabetes and metabolic syndrome have been well recognized in shift workers. Recent human studies strongly implicate a 'dose-dependent' relationship between circadian disruption and diabetes. Genetic and environmental disruption of the circadian clock in rodents leads to diabetes secondary to ß-cell failure. Deletion of Bmal1, a non-redundant core clock gene, leads to defects in ß-cell stimulus-secretion coupling, decreased glucose-stimulated ATP production, uncoupling of OXPHOS and impaired glucose-stimulated insulin secretion. Both genetic and environmental circadian disruptions are sufficient to induce oxidative stress and this is mediated by a disruption of the direct transcriptional control of the core molecular clock and Bmal1 on Nrf2, the master antioxidant transcription factor in the ß-cell. In addition, circadian disruption also leads to a dysregulation of the unfolded protein response and leads to endoplasmic reticulum stress in ß-cells. Both the oxidative and endoplasmic reticulum (ER) stress contribute to an impairment of mitochondrial function and ß-cell failure. Understanding the basis of the circadian control of these adaptive stress responses offers hope to target them for pharmacological modulation to prevent and mitigate the deleterious metabolic consequences of circadian disruption.

Epidemiological study of myiases in the Hospital do Andaraí, Rio de Janeiro, including reference to an exotic etiological agent.

Myiases are infestations with dipteran larvae in both necrosed and living tissues, the food source of these insects. These illnesses occur in warm humid climates, and are most frequent in developing countries. We assessed the epidemiological aspects and the influence of climate on the occurrence of myiases and the bioagents in patients admitted to the federal Hospital do Andaraí in Rio de Janeiro from February 2007 to 2008. The influence of abiotic factors (temperature, humidity, and rainfall) on the incidence of myiases was investigated by using the Pearson's correlation test. Of the 40 patients studied, the prevalence of myiases was higher in adults, particularly in the 40 to 65 year-old (37.5%) African descent males (57.5%). Most of the injuries were caused by trauma (62.5%). Some patients made use of licit (50%) and illicit drugs (17.2%). The occurrence of myiases was not affected by the abiotic factors investigated. The cases reported here were treated in only one hospital, indicating that the disease is relatively common. The most frequent bioagent was Cochliomyia hominivorax (Coquerel), but Cochliomyia macellaria (Fabricius), Chrysomya albiceps (Wiedemann) and Dermatobia hominis (Wiedemann) (Diptera: Calliphoridae) were also detected causing myiases. Chrysomya albiceps is an exotic etiologic agent of myiases.

Molybdenum determination in iron matrices by ICP-AES after separation and preconcentration using polyurethane foam.

A procedure is proposed for the separation and determination of molybdenum in iron matrices by a batch process. It is based on the solid-phase extraction of the molybdenum(V) ion as thiocyanate complex on polyurethane (PU) foam. The extraction parameters were optimized. Using 0.20 mol L-1 hydrochloric acid, a thiocyanate concentration of 0.10 mol L-1, 100 mg of polyurethane foam and shaking time of 10 min, molybdenum (5-400 micrograms) can be separated and preconcentrated from large amounts of iron (10 mg). Desorption was carried out instantaneously by conc. nitric acid or acetone. Distribution coefficients, sorption capacity of the PU foam and coefficients of variation were also evaluated. The effect of some ions on the separation procedure was assessed. Iron(III) should be reduced to iron(II). The proposed procedure was used to determine molybdenum in standard iron matrices such as steel and pure iron. The achieved results did not show significant differences with certified values.

Quantitative separation of zinc traces from cadmium matrices by solid-phase extraction with polyurethane foam.

A system for separation of zinc traces from large amounts of cadmium is proposed in this paper. It is based on the solid-phase extraction of the zinc in the form of thiocyanate complexes by the polyurethane foam. The following parameters were studied: effect of pH and of the thiocyanate concentration on the zinc extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction, conditions for the separation of zinc from cadmium, influence of other cations and anions on the zinc sorption by PU foam, and required conditions for back extraction of zinc from the PU foam. The results show that zinc traces can be separated from large amounts of cadmium at pH 3.0+/-0.50, with the range of thiocyanate concentration from 0.15 to 0.20 mol l(-1), and the shaking time of 5 min. The back extraction of zinc can be done by shaking it with water for 10 min. Calcium, barium, strontium, magnesium, aluminum, nickel and iron(II) are efficiently separated. Iron(III), copper(II) and cobalt(II) are extracted simultaneously with zinc, but the iron reduction with ascorbic acid and the use of citrate to mask copper(II) and cobalt(II) increase the selectivity of the zinc extraction. The anions nitrate, chloride, sulfate, acetate, thiosulphate, tartarate, oxalate, fluoride, citrate, and carbonate do not affect the zinc extraction. Phosphate and EDTA must be absent. The method proposed was applied to determine zinc in cadmium salts using 4-(2-pyridylazo)-resorcinol (PAR) as a spectrophotometric reagent. The result achieved did not show significant difference in the accuracy and precision (95% confidence level) with those obtained by ICP-AES analysis.

Derivative spectrophotometric determination of nickel using Br-PADAP.

A major problem with spectrophotometric methods for nickel is cobalt interference, because many of the reagents for nickel also react with cobalt. In this work, the interference of cobalt in the determination of nickel using 2-(5-bromo-2-pyridylaxo)-5-diethylaminophenol (Br-PADAP) was eliminated by the use of derivative spectrophotometry, using the zero-crossing method for evaluation of the derivative signal. Br-PADAP reacts with nickel(II) in the presence of Triton X-100 to form a red complex with absorption maxima at 530 and 562 nm. The reactions parameters and the conditions for the measurements of the first-derivative signal were studied and the results demonstrated that using the derivative technique, Br-PADAP can be used for nickel determination with a selectivity higher than that of ordinary spectrophotometry and with a limit of detection of 0.2 ng ml(-1). The pH should be in the range 5.0-6.0 using an acetate buffer. The determination of nickel in the presence of cobalt was performed with conventional and derivative procedures, and the results demonstrated that only the derivative method should be used and, of the methods used for evaluation of the derivative signal, the zero-crossing method is the best. The proposed procedure was used for nickel determination in steels standards. The results demonstrated that the procedure has satisfactory accuracy and precision. Cobalt interference can be also eliminated by using dual-wave-length spectroscopy.

Characteristics of the immune response in a patient with Whipple's disease.

A patient with Whipple's disease has been studied to examine the effect of antibiotic therapy on the immune status of the patient, and the specific immune response to a cell wall deficient form of an alpha-haemolytic streptococcus (alpha HS) isolated from this patient. T lymphocyte numbers were reduced, and cutaneous anergy was present. Autoantibodies directed against smooth muscle and mitochondria were detected. These abnormal parameters became normal following antibiotic therapy. The specific immune response to the alphaHS was characterised by IgA antibody and lymphocyte sensitisation. The latter was detected as antigen-inducedd lymphocyte stimulation and antigen-induced leucocyte inhibition factor (LIF) production. Antibiotic therapy was associated with a fall in antibody titre and reduced LIF production. No defect in neutrophil function was found. These results are most consistent with the postulates that (i) immunological abnormalities in Whipple's disease are secondary to infection and (ii) the primary abnormality is an unusual pathogenic bacterium.

Circulating T and B lymphocytes in progressive systemic sclerosis.

Thymus derived (T) and bone-marrow derived (B) lymphocytes were quantitated in 11 untreated patients with progressive systemic sclerosis (PSS) and in 11 age and sex matched controls. T and B lymphocytes were identified according to their receptor sites for sheep red blood cells and activated complement, respectively. All patients had a normal lymphocyte count. The mean per cent value of circulating T lymphocytes was less in PSS patients (38 per cent) as compared with controls (56 per cent) (P less than 0.005), while no significant difference existed for the circulating B lymphocytes (PSS 14 per cent; controls 11 per cent). The mitogenic response to phytohemagglutinin (PHA) was assessed by comparing dose response curves in PSS with those obtained from matched controls. No significant difference could be detected between these groups.