RANK ligand converts the NCoR/HDAC3 co-repressor to a PGC1β- and RNA-dependent co-activator of osteoclast gene expression

The nuclear receptor co-repressor (NCoR) complex mediates transcriptional repression dependent on histone deacetylation by histone deacetylase 3 (HDAC3) as a component of the complex. Unexpectedly, we found that signaling by the receptor activator of nuclear factor κB (RANK) converts the NCoR/HDAC3 co-repressor complex to a co-activator of AP-1 and NF-κB target genes that are required for mouse osteoclast differentiation. Accordingly, the dominant function of NCoR/HDAC3 complexes in response to RANK signaling is to activate, rather than repress, gene expression. Mechanistically, RANK signaling promotes RNA-dependent interaction of the transcriptional co-activator PGC1β with the NCoR/HDAC3 complex, resulting in the activation of PGC1β and inhibition of HDAC3 activity for acetylated histone H3. Non-coding RNAs Dancr and Rnu12, which are associated with altered human bone homeostasis, promote NCoR/HDAC3 complex assembly and are necessary for RANKL-induced osteoclast differentiation in vitro. These findings may be prototypic for signal-dependent functions of NCoR in other biological contexts.

Multisensory effects of mask wearing on speech intelligibility and the benefit of multilingualism

PURPOSE

Due to the pandemic of the Covid-19 disease, it became common to wear masks on some public spaces. By covering mouth and nose, visual-related speech cues are greatly reduced, while the auditory signal is both distorted and attenuated. The present study aimed to analyze the multisensory effects of mask wearing on speech intelligibility and the differences in these effects between participants who spoke 1, 2 and 3 languages.

METHODS

The study consisted of the presentation of sentences from the SPIN test to 40 participants. Participants were asked to report the perceived sentences. There were four conditions: auditory with mask; audiovisual with mask; auditory without mask; audiovisual without mask. Two sessions were conducted, one week apart, each with the same stimuli but with a different signal-to-noise ratio.

RESULTS

Results demonstrated that the use of the mask decreased speech intelligibility, both due to a decrease in the quality of auditory stimuli and due to the loss of visual information. Signal-to-noise ratio largely affects speech intelligibility and higher ratios are needed in mask-wearing conditions to obtain any degree of intelligibility. Those who speak more than one language are less affected by mask wearing, as are younger listeners.

CONCLUSION

Wearing a facial mask reduces speech intelligibility, both due to visual and auditory factors. Older people and people who only speak one language are affected the most.

Decorative Chromium Coatings on Polycarbonate Substrate for the Automotive Industry

Metal-coated plastic parts are replacing traditional metallic materials in the automotive industry. Sputtering is an alternative technology that is more environmentally friendly than electrolytic coatings. Most metalized plastic parts are coated with a thin metal layer (~100-200 nm). In this work, the challenge is to achieve thicker films without cracking or without other defects, such as pinholes or pores. Chromium coatings with different thicknesses were deposited onto two different substrates, polycarbonate with and without a base coat, using dc magnetron sputtering in an atmosphere of Ar. Firstly, in order to improve the coating adhesion on the polymer surface, a plasma etching treatment was applied. The coatings were characterized for a wide thickness range from 800 nm to 1600 nm. As the thickness of the coatings increased, there was an increase in the specular reflectivity and roughness of the coatings and changes in morphology due to the columnar growth of the film and a progressive increase in thermal stresses. Furthermore, a decrease in the hardness and the number of pinholes was noticed. The maximum thickness achieved without forming buckling defects was 1400 nm. The tape tests confirmed that every deposited coating showed a good interface adhesion to both polymers.

Mitochondrial Sirt3 contributes to the bone loss caused by aging or estrogen deficiency

Altered mitochondria activity in osteoblasts and osteoclasts has been implicated in the loss of bone mass associated with aging and estrogen deficiency — the 2 most common causes of osteoporosis. However, the mechanisms that control mitochondrial metabolism in bone cells during health or disease remain unknown. The mitochondrial deacetylase sirtuin-3 (Sirt3) has been earlier implicated in age-related diseases. Here, we show that deletion of Sirt3 had no effect on the skeleton of young mice but attenuated the age-related loss of bone mass in both sexes. This effect was associated with impaired bone resorption. Osteoclast progenitors from aged Sirt3-null mice were able to differentiate into osteoclasts, though the differentiated cells exhibited impaired polykaryon formation and resorptive activity, as well as decreased oxidative phosphorylation and mitophagy. The Sirt3 inhibitor LC-0296 recapitulated the effects of Sirt3 deletion in osteoclast formation and mitochondrial function, and its administration to aging mice increased bone mass. Deletion of Sirt3 also attenuated the increase in bone resorption and loss of bone mass caused by estrogen deficiency. These findings suggest that Sirt3 inhibition and the resulting impairment of osteoclast mitochondrial function could be a novel therapeutic intervention for the 2 most important causes of osteoporosis.

A decrease in NAD+ contributes to the loss of osteoprogenitors and bone mass with aging

Age-related osteoporosis is caused by a deficit in osteoblasts, the cells that secrete bone matrix. The number of osteoblast progenitors also declines with age associated with increased markers of cell senescence. The forkhead box O (FoxO) transcription factors attenuate Wnt/β-catenin signaling and the proliferation of osteoprogenitors, thereby decreasing bone formation. The NAD⁺-dependent Sirtuin1 (Sirt1) deacetylates FoxOs and β-catenin in osteoblast progenitors and, thereby, increases bone mass. However, it remains unknown whether the Sirt1/FoxO/β-catenin pathway is dysregulated with age in osteoblast progenitors. We found decreased levels of NAD⁺ in osteoblast progenitor cultures from old mice, associated with increased acetylation of FoxO1 and markers of cell senescence. The NAD⁺ precursor nicotinamide riboside (NR) abrogated FoxO1 and β-catenin acetylation and several marker of cellular senescence, and increased the osteoblastogenic capacity of cells from old mice. Consistent with these effects, NR administration to C57BL/6 mice counteracted the loss of bone mass with aging. Attenuation of NAD⁺ levels in osteoprogenitor cultures from young mice inhibited osteoblastogenesis in a FoxO-dependent manner. In addition, mice with decreased NAD⁺ in cells of the osteoblast lineage lost bone mass at a young age. Together, these findings suggest that the decrease in bone formation with old age is due, at least in part, to a decrease in NAD⁺ and dysregulated Sirt1/FoxO/β-catenin pathway in osteoblast progenitors. NAD⁺ repletion, therefore, represents a rational therapeutic approach to skeletal involution.

Cxcl12 Deletion in Mesenchymal Cells Increases Bone Turnover and Attenuates the Loss of Cortical Bone Caused by Estrogen Deficiency in Mice

CXCL12 is abundantly expressed in reticular cells associated with the perivascular niches of the bone marrow (BM) and is indispensable for B lymphopoiesis. Cxcl12 promotes osteoclastogenesis and has been implicated in pathologic bone resorption. We had shown earlier that estrogen receptor α deletion in osteoprogenitors and estrogen deficiency in mice increase Cxcl12 mRNA and protein levels in the BM plasma, respectively. We have now generated female and male mice with conditional deletion of a Cxcl12 allele in Prrx1 targeted cells (Cxcl12^∆Prrx1 ) and show herein that they have a 90% decrease in B lymphocytes but increased erythrocytes and adipocytes in the marrow. Ovariectomy increased the expression of Cxcl12 and B-cell number in the Cxcl12^f/f control mice, but these effects were abrogated in the Cxcl12^∆Prrx1 mice. Cortical bone mass was not affected in Cxcl12^∆Prrx1 mice. Albeit, the cortical bone loss caused by ovariectomy was greatly attenuated. Most unexpectedly, the rate of bone turnover in sex steroid-sufficient female or male Cxcl12^∆Prrx1 mice was dramatically increased, as evidenced by a more than twofold increase in several osteoblast- and osteoclast-specific mRNAs, as well as increased mineral apposition and bone formation rate and increased osteoclast number in the endosteal surface. The magnitude of the Cxcl12^∆Prrx1 -induced changes were much greater than those caused by ovariectomy or orchidectomy in the Cxcl12^f/f mice. These results strengthen the evidence that CXCL12 contributes to the loss of cortical bone mass caused by estrogen deficiency. Moreover, they reveal for the first time that in addition to its effects on hematopoiesis, CXCL12 restrains bone turnover-without changing the balance between resorption and formation-by suppressing osteoblastogenesis and the osteoclastogenesis support provided by cells of the osteoblast lineage. © 2020 American Society for Bone and Mineral Research.

Estrogens decrease osteoclast number by attenuating mitochondria oxidative phosphorylation and ATP production in early osteoclast precursors

Loss of estrogens at menopause is a major cause of osteoporosis and increased fracture risk. Estrogens protect against bone loss by decreasing osteoclast number through direct actions on cells of the myeloid lineage. Here, we investigated the molecular mechanism of this effect. We report that 17β-estradiol (E₂) decreased osteoclast number by promoting the apoptosis of early osteoclast progenitors, but not mature osteoclasts. This effect was abrogated in cells lacking Bak/Bax-two pro-apoptotic members of the Bcl-2 family of proteins required for mitochondrial apoptotic death. FasL has been previously implicated in the pro-apoptotic actions of E₂. However, we show herein that FasL-deficient mice lose bone mass following ovariectomy indistinguishably from FasL-intact controls, indicating that FasL is not a major contributor to the anti-osteoclastogenic actions of estrogens. Instead, using microarray analysis we have elucidated that ERα-mediated estrogen signaling in osteoclast progenitors decreases "oxidative phosphorylation" and the expression of mitochondria complex I genes. Additionally, E₂ decreased the activity of complex I and oxygen consumption rate. Similar to E₂, the complex I inhibitor Rotenone decreased osteoclastogenesis by promoting osteoclast progenitor apoptosis via Bak/Bax. These findings demonstrate that estrogens decrease osteoclast number by attenuating respiration, and thereby, promoting mitochondrial apoptotic death of early osteoclast progenitors.

Peritoneal dissemination of ovarian cancer: role of MUC16-mesothelin interaction and implications for treatment

INTRODUCTION

Peritoneal dissemination is a particular form of malignant progression in ovarian cancer, preceding hematogenic or lymphatic dissemination. Thus, prevention of peritoneal implantation of cancer cells is envisioned to inhibit neoplastic dissemination and therefore prolong disease remission and patient's survival. Areas covered: An extended review on the role of MUC16 (CA125) and mesothelin (MSLN), expressed in a high percentage of ovarian carcinomas, indicate that this duet is relevant for the contact between cancer cells and mesothelial cells in homotypic (cancer cell-cancer cell) and heterotypic (cancer cell-mesothelial cell) interactions. This review discusses the reasons underlying the clinical failure of immunotherapeutic strategies targeting MUC16. Clinical data on MSLN targeting agents such as antibody-based immunotoxins or antibody drug conjugates are also reviewed. The promising anti-tumor effect of CAR-T cells directed to MUC16 or MSLN is emphasized. New emerging strategies specifically disrupting the MUC16-MSLN interaction are at the forefront of this review, including TRAIL ligands bound to MSLN targeting MUC16 expressing cells and single chain monoclonal antibodies and immunoadhesins recognizing MSLN-MUC16 binding domains. Expert commentary: Based on existing evidences the authors advocate that agents targeting MUC16-MSLN may add to the therapeutic armamentarium directed to abrogate peritoneal homing of ovarian cancer.

Single Low-Dose Ionizing Radiation Induces Genotoxicity in Adult Zebrafish and its Non-Irradiated Progeny

This study investigated to what extent a single exposure to low doses of ionizing radiation can induce genotoxic damage in irradiated adult zebrafish (Danio rerio) and its non-irradiated F1 progeny. Four groups of adult zebrafish were irradiated with a single dose of X-rays at 0 (control), 100, 500 and 1000 mGy, respectively, and couples of each group were allowed to reproduce following irradiation. Blood of parental fish and whole-body offspring were analysed by the comet assay for detection of DNA damage. The level of DNA damage in irradiated parental fish increased in a radiation dose-dependent manner at day 1 post-irradiation, but returned to the control level thereafter. The level of DNA damage in the progeny was directly correlated with the parental irradiation dose. Results highlight the genotoxic risk of a single exposure to low-dose ionizing radiation in irradiated individuals and also in its non-irradiated progeny.

Quantification of 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5), a newly synthetized P-glycoprotein inducer/activator, in biological samples: method development and validation

A simple, rapid and economical method was developed and validated for the analysis and quantification of 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5), a P-glycoprotein inducer/activator, in biological samples, using reverse-phase high-performance liquid chromatography (HPLC). A C₁₈ column and a mobile phase composed of methanol-water (90/10, v/v) with 1% (v/v) triethylamine, at a flow rate of 1 mL/min, were used for chromatographic separation. TX5 standards (0.5-150 μm) were prepared in human serum. Methanol was used for TX5 extraction and serum protein precipitation. After filtration, samples were injected into the HPLC apparatus and TX5 was quantified by a conventional UV detector at 255 nm. The TX5 retention time was 13 min in this isocratic system. The method was validated according to ICH guidelines for specificity/selectivity, linearity, accuracy, precision, limits of detection and quantification (LOD and LOQ) and recovery. The method was proved to be selective, as there were no interferences of endogenous compounds with the same retention time of TX5. Also, the developed method was linear (r²  ≥ 0.99) for TX5 concentrations between 0.5 and 150 μm and the LOD and LOQ were 0.08 and 0.23 μm, respectively. The results indicated that the reported method could meet the requirements for TX5 analysis in the trace amounts expected to be present in biological samples.

Improvement of genetic stability in lymphocytes from Fanconi anemia patients through the combined effect of α-lipoic acid and N-acetylcysteine

Fanconi Anemia (FA) is a rare genetic disorder, characterized by progressive bone marrow failure and increased predisposition to cancer. Despite being highly heterogeneous, all FA patients are hypersensitive to alkylating agents, in particular to 1,2:3,4-diepoxybutane (DEB), and to oxidative damage. Recent studies point to defective mitochondria in FA cells, which is closely related with increased production of reactive oxygen species (ROS) and concomitant depletion of antioxidant defenses, of which glutathione is a well-known biomarker.The objective of the present work is to evaluate the putative protective effect of α-lipoic acid (α-LA), a mitochondrial protective agent, and N-acetylcysteine (NAC), a direct antioxidant and a known precursor for glutathione synthesis, in spontaneous and DEB-induced chromosome instability (CI) in lymphocyte cultures from FA patients.For that purpose, lymphocyte cultures from 15 FA patients and 24 healthy controls were pre-treated with 20 μM α-LA, 500 μM NAC and α-LA plus NAC at the same concentrations, and some of them were exposed to DEB (0.05 μg/ml). A hundred metaphases per treatment were scored to estimate the relative frequency of spontaneous and DEB-induced chromosome breakage.The obtained results revealed that a cocktail of α-LA and NAC can drastically improve the genetic stability in FA lymphocytes in vitro, decreasing CI by 60% and 80% in cultures from FA patients and FA mosaic/chimera patients, respectively. These results suggest that the studied cocktail can be used as a prophylactic approach to delay progressive clinical symptoms in FA patients caused by CI, which can culminate in the delay of the progressive bone marrow failure and early cancer development.

Protective effect of acetyl-l-carnitine and α-lipoic acid against the acute toxicity of diepoxybutane to human lymphocytes

The biotransformation and oxidative stress may contribute to 1,2:3,4-diepoxybutane (DEB)-induced toxicity to human lymphocytes of Fanconi Anemia (FA) patients. Thus, the identification of putative inhibitors of bioactivation, as well as the determination of the protective role of oxidant defenses, on DEB-induced toxicity, can help to understand what is failing in FA cells. In the present work we studied the contribution of several biochemical pathways for DEB-induced acute toxicity in human lymphocyte suspensions, by using inhibitors of epoxide hydrolases, inhibitors of protective enzymes as glutathione S-transferase and catalase, the depletion of glutathione (GSH), and the inhibition of protein synthesis; and a variety of putative protective compounds, including antioxidants, and mitochondrial protective agents. The present study reports two novel findings: (i) it was clearly evidenced, for the first time, that the acute exposure of freshly isolated human lymphocytes to DEB results in severe GSH depletion and loss of ATP, followed by cell death; (ii) acetyl-l-carnitine elicits a significant protective effect on DEB induced toxicity, which was potentiated by α-lipoic acid. Collectively, these findings contribute to increase our knowledge of DEB-induce toxicity and will be very useful when applied in studies with lymphocytes from FA patients, in order to find out a protective agent against spontaneous and DEB-induced chromosome instability.

[Fanconi anemia: cytogenetic diagnosis of 40 cases]

Fanconi Anemia (FA) is a rare recessive disorder clinically characterized by progressive bone marrow failure, diverse congenital malformations and increased predisposition to cancer. Given the late onset of anemia, relatively to other cytopenias, and the high variability in the phenotype, a correct clinical diagnosis is difficult, and may be delayed or even missed. This fact may be prejudicial to patients, due to the need of avoiding exposure to toxic agents, programming the transplantation of hematopoietic progenitor cells and screening of neoplasia associated with the disease. Given the high genetic variability (thirteen complementation groups have been identified, each with genes presenting several different mutations), a rapid molecular diagnosis is not possible. However, there is an urgent need for a timely and correct diagnosis, due to the early evolution of the disease towards malignancy and to the early need of finding compatible donors for future hematopoietic stem cell transplantation. Fortunately, the hypersensitivity of FA cells to the clastogenic (chromosome breaking) effect of DNA cross-linking agents, in particular to diepoxybutane (DEB), provides a unique marker for the diagnosis. At present, cytogenetic analysis for detection of DEB-induced chromosome instability is the gold-standard test for the diagnosis of FA. In the present work we present the results from the DEB induced chromosome instability studies performed in the Laboratory of Cytogenetics of ICBAS between 1992 and 2009. Blood samples from 222 patients were obtained from different hospitals mainly from the north and centre of Portugal. This population includes not only patients with clinical suspicion of FA, but also patients presented with thrombocytopenia, pancitopenia or aplastic anemia, for confirmation/exclusion of FA. Two samples of amniotic fluid were also obtained for pre-natal diagnosis. A total of 34 FA patients were diagnosed. Cytogenetic studies were also performed in blood samples from AF relatives, which allowed the diagnosis of 6 new cases, 5 of them corresponding to asymptomatic individuals. In the total population of FA patients studied, 25% belong to the gypsy ethnic group. Periodic cytogenetic studies were also performed in blood samples from AF patients post transplantation, which confirmed the elimination of the original hematopoietic DEB sensitive cells.

Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.

Development of physical and numerical techniques of Alanine/EPR dosimetry in radiotherapy

In this work, a set of 50 alanine dosimeters has been used in a radiotherapy context, simulating a two-dimensional treatment in a non-overlapping dosimeter configuration. The dose is reconstructed from physical and numerical simulation of the electron paramagnetic resonance signal, calculating the spin density. Thus, it can be used to better adjust the error in the calibration curve to give a final accuracy of <0.03 Gy. A complete set of experimental test parameters have been used with a standard dosimeter in order to obtain the best analysis configuration. These results indicate that for a conventional treatment of some hundreds of mGy, this method can be useful with a correct signal validation. A numerical test and fitting software has been developed. The general use of alanine/electron paramagnetic resonance dosimetry in radiotherapy context is discussed.

Electro-oculographic abnormality in eyes with uveal melanoma

PURPOSE

To seek out correlations between preoperative electro-oculogram (EOG) recordings with different types of uveal melanomas, after surgery.

METHODS

We analysed the EOG recordings of 120 patients with uveal melanomas, histologically verified, 100 in the choroid and 20 in the iris and ciliary body. The EOG data were correlated with the site, size and histological type of the tumor.

RESULTS

In 100 eyes with choroidal melanoma the Arden Index (AI) was less than in fellow eyes (mean 126.6, SD +/- 23.8 and 202.9, SD +/- 47.0; p=0.01). The EOG values were not different with respect to the histological type, site and size of tumor. In cases with iris and ciliary body melanomas the AI were not significantly different from the fellow eyes (mean 180.6, SD +/- 23.6 and 203.2, SD +/- 38.7; p=0.07).

CONCLUSIONS

Since the EOG is abnormal in eyes with choroidal melanoma, it can be considered a powerful auxiliary for diagnosing these tumors.

Plain film, CT and MRI sensibility in the evaluation of intraorbital foreign bodies in an in vitro model of the orbit and in pig eyes

Detection and characterization of intraorbital foreign bodies (IFB) is fundamental in acute trauma setting, preventing inflammatory sequelae or complications related to IFB movements when a MRI study is planned. Papers concerning plain film and CT sensibility in IFB detection show controversial results. For this reason we investigated plain film, CT and MRI sensibility in the evaluation of IFB. For an in vitro model, specimens of dry and fresh wood, glass, iron, plastic and graphite were immersed in animal lard and in a 0.9% sodium chloride plus 3.5 g/dl human serum albumin solution. Specimens of different size and nature where also implanted into enucleated pig eyes. Air bubbles were introduced also. Plain film, CT and MRI investigation were performed. Plain films underestimated intraocular IFB as plastic, fresh or dry wooden IFB were not demonstrated. The CT study was always able to depict and differentiate IFB according to the attenuation values. Severe artefacts prevented demonstration of iron, glass and graphite IFB on MRI, whereas plastic or wooden IFB were always detected. Despite radiographs have been suggested as a prerequisite for MR imaging, because our results showed plain film to underestimate radiolucent IFB, we suggest CT as the modality of choice when IFB has to be ruled out.

MR dacryocystography: comparison with dacryocystography and CT dacryocystography

BACKGROUND AND PURPOSE

Several techniques have been used to image the nasolacrimal system, providing functional (dacryoscintigraphy) or morphologic (dacryocystography, CT dacryocystography [CTD]) information. Using gadopentetate dimeglumine-diluted solution injected into the lacrimal canaliculus or instilled into the conjunctival sac, we compared the sensitivity of MR dacryocystography (MRD) with that of CTD.

METHODS

Eleven healthy volunteers and 25 patients affected by primary epiphora (21 patients) or postsurgical recurrent epiphora (four patients) underwent MRD after the topical administration of contrast media or cannulation of the lacrimal canaliculus. The MR imaging findings were compared with irrigation and CTD data. All patients underwent surgical treatment (dacryocystorhinostomy), which served as a standard of reference for confirming the MRD findings.

RESULTS

The topical administration of contrast-enhanced saline solution and the injection of contrast-enhanced saline solution after cannulation were always well tolerated. In healthy volunteers, outflow of contrast media was always revealed by MRD. Eight (32%) of 25 patients with epiphora had stenosis proximal to the lacrimal sac revealed by MRD, whereas 17 (68%) of 25 showed a dilated lacrimal sac and nasolacrimal duct stenosis, as confirmed by surgical findings. The findings of MRD after the topical administration of contrast medium and MRD after cannulation of the lacrimal canaliculus were comparable with irrigation or CTD data for all patients except one.

CONCLUSION

In patients with epiphora, MR imaging performed after the topical administration of diluted contrast material can reveal stenosis of the lacrimal apparatus and can be added to the standard orbital imaging protocol when lacrimal system involvement is suspected.

Crowding Norms in Marine Settings: A Case Study of Snorkeling on the Great Barrier Reef

/ Research on crowding in natural environments has traditionally been concerned with encounters in terrestrial settings. Increased visitation to tropical marine environments, however, has meant that evaluations of aesthetic quality are increasingly becoming issues for managers of marine parks. In this study, we used image-capture techniques to develop a series of above- and below-water images depicting different numbers of people snorkeling in acoral reef setting. The presence of safety facilities in the above-water settings was manipulated to examine the influence of human-made structures on perception of crowding. Four respondent groups-a scuba-diving club, local residents, tourists, and US university students-representing different levels of experience in marine recreation on the Great Barrier Reef, were asked to rate the acceptability of each image. Ratings were significantly influenced by the number of people in the images, the prior experience and gender of the respondents, and the presence of safety infrastructure. Experienced scuba divers preferred scenes without people or infrastructure, while novices regarded the presence of both as more acceptable. The results suggest that evaluations of social density and crowding may vary between below-water scenes and the more familiar above-water setting. A lack of concordance between how respondents rated the images and their nominated preferences for the number of other people in the settings highlights a need for more research on how perceptions of resource conditions should be measured in marine environments.KEY WORDS: Recreation; Great Barrier Reef Marine Park; Image capture technology; Crowding norms; Snorkelinghttp://link.springer-ny.com/link/service/journals/00267/bibs/24n3p369.html

Topical lomefloxacin 0.3% twice daily versus tobramycin 0.3% in acute bacterial conjunctivitis: A multicenter double-blind phase III study

AIMS/BACKGROUND

To evaluate in a double-masked comparative, prospective, randomized multicenter trial the efficacy of lomefloxacin 0.3% eye drops twice daily and of tobramycin eye drops 4 times daily in patients with acute bacterial conjunctivitis.

METHODS

Ninety-nine subjects were enrolled: 50 were treated with lomefloxacin 0.3% eye drops twice daily and 49 with tobramycin 0.3% eye drops 4 times daily. In all patients, conjunctival swabbing and assessment of objective signs and of subjective symptoms were performed.

RESULTS

There was no statistical difference for any individual sign or symptom or for the sum score of either key or other signs and symptoms at any of the examination days. The sum score of both key and other signs and symptoms decreased in both groups at day 3-4 as compared to baseline values (p < 0.0001). The decrease in both these scores continued significantly from day 3-4 to day 7-8 (p < 0.05) and was similar in the two treatment groups (p > 0.4). The lowest resistance rate was seen in lomefloxacin (3.5%) and in neomycin (7.0%), while tobramycin showed resistance in 10 out of 88 resistance strains (11.4%).

CONCLUSION

Both lomefloxacin 0.3% twice daily and tobramycin 0.3% administered 4 times daily were well tolerated and showed a high degree of clinical and microbiological efficacy in the treatment of acute bacterial conjunctivitis. Lomefloxacin caused less resistance than other antibiotics evaluated.

Efficacy and safety of combined diclofenac 0.1% and gentamicin 0.3% eyedrops after phacoemulsification

PURPOSE

To study the efficacy of combined diclofenac 0.1% and gentamicin 0.3% (Digen) eyedrops to treat postoperative inflammation and prevent ocular infection in eyes having phacoemulsification.

SETTING

Department of Ophthalmology, University of Milan, San Paolo Hospital, Milan; Eye Clinic, University of Verona; and Department of Ophthalmology, University of Palermo, Italy.

METHODS

This double-masked, randomized, clinical trial comprised 90 patients; 45 received Digen and 45, gentamicin 0.3% eyedrops. The main outcome measure of the study was the reduction in signs and symptoms of inflammation, graded on a four-point scale. Also assessed were the presence of bacteria in the conjunctival swab and the proportion of patients requiring additional medication.

RESULTS

Digen was more effective in reducing postoperative inflammation than gentamicin alone (P < .01). No statistically significant between-group difference was found regarding antibacterial activity. Both treatments were well tolerated throughout the study.

CONCLUSION

Digen seemed to maintain the properties and activities of each individual drug, making it a promising treatment for reducing inflammation after phacoemulsification.

Temporal versus superior approach phacoemulsification: short-term postoperative astigmatism

PURPOSE

To compare short-term clinical, postoperative astigmatism, and uncorrected visual acuity results 2 months after no-stitch phacoemulsification using a temporal clear corneal approach and poly(methyl methacrylate) (PMMA) intraocular lens (IOL) implantation through a 5.2 mm incision with those after no-stitch superior corneoscleral phacoemulsification.

SETTING

University Eye Clinic of Palermo, Italy.

METHODS

This prospective clinical trial comprised 80 patients with senile cataract who were randomly assigned to have phacoemulsification using a temporal approach or a superior approach. Surgically induced astigmatism (SIA) was calculated using Naeser's polar value method for determining with-the-rule (WTR) or against-the-rule (ATR) change.

RESULTS

There was a highly significant between-group difference in SIA at each examination (P < .001; t-test) because of positive (WTR) SIA in the temporal approach group and negative (ATR) SIA in the superior approach group. No other significant differences between groups were found (P < .05, t-test). More patients in the temporal group had an uncorrected visual acuity of 20/25 or better 2 weeks postoperatively, although the difference between groups was not statistically significant (P = .562; chi-square).

CONCLUSION

Phacoemulsification using a no-stitch, temporal, 5.2 mm clear corneal incision produced results comparable to those using a corneoscleral superior approach. A longer study of a larger series should be done to confirm the findings.

Blood-ocular barrier damage: use of contrast-enhanced MRI

The blood-ocular barrier (BOB) shares similar neuroepithelial origin, microanatomy and functions with the blood-brain barrier. There are many natural (e. g. diabetes, hypertension) or iatrogenic (chemotherapy, retinal photocoagulation) conditions which can cause a BOB breakdown, resulting in visual acuity impairment or loss. The authors examined 42 patients affected by BOB damage in different pathological conditions. All patients previously underwent a conventional fluoroangiographic (FA) study. Nine patients with normal FA exam were evaluated also. Despite normal MRI findings immediately after Gd-DTPA injection, contrast leakage into the vitreous body or into the aqueous fluid was demonstrated in delayed scans (40-50 min after contrast administration), proving the existence of a BOB damage (sensitively 94 %). Although FA exam remains the choice modality in BOB breakdown demonstration, we propose MRI as a useful diagnostic tool when optic media opacity (cataract, haemovitreous, intraocular silicon oil) occurs, preventing direct retinal fundus imaging and/or an early screening tool.

Idiopathic intracranial hypertension: orbital MRI

The case is reported of a patient with idiopathic intracranial hypertension examined with magnetic resonance imaging. Marked enhancement of the optic nerve heads was found, which might be related to blood-retinal barrier breakdown related to a sudden rise in intracranial cerebrospinal fluid pressure.

Prevalence of glaucoma and distribution of intraocular pressure in a population. The Casteldaccia Eye Study

IOP was measured in 1062 middle-aged and elderly subjects of a small Sicilian town, enrolled in a population based survey. The mean IOP was 15.1 +/- 3.7 mmHg without interocular or sex differences. A small but significant age-dependent increase of IOP was found. Circadian and seasonal influences were recorded: IOP was higher in the morning and in winter. The prevalence of chronic open-angle glaucoma was 1.2%, but it grew to 3.6 if only subjects aged 70 years or more were considered. IOP of 24 mmHg or more was found in 2.7%, while 4.3% of subjects showed IOP of 21 mmHg or more. This survey shows that mean IOP of the Mediterranean population studied is similar to the IOP found in other epidemiologic investigations; the prevalence of glaucoma, however, seems to be rather high.

Surgical therapy for obesity can induce a vitamin A deficiency syndrome

New possible causes and unexplored aspects of the electroretinogram were evaluated in a case of vitamin A deficiency secondary to surgical therapy for morbid obesity. The Naka-Rushton equation, applied to the scotopic b-wave, demonstrated the quantal catch reduction caused by the loss of rhodopsin in the outer segment of photoreceptors. Study of the Fourier analysis of the photopic 20-Hz response suggested a primary involvement of the external retinal layers, with an indirect alteration of the inner layer. The electroretinogram oscillatory potentials showed alterations explained by the involvement of their generators related to the primary photoreceptor lesion.

Casteldaccia eye study: prevalence of cataract in the adult and elderly population of a Mediterranean town

Prevalence of cataract was studied in a population based survey performed in adults aged 40 years or more living in Casteldaccia, a small Sicilian town. Lens opacities of moderate or severe grade (type II or worse, according to the Lens Opacity Classification System II) were found at the following rates: nuclear opalescence in 18.5%, cortical cataract in 12.9%, posterior subcapsular cataract in 10.8%. All these types of cataract were much more frequent in the elderly population and were about 1.5 times more common in women than in men. Late cataract was found in about 1/3 of subjects aged 60 to 69 years, in 2/3 of subjects aged 70 or more, but rarely under 60 years of age. However, early cataract was rather common among younger subjects. Cataracts causing a reduction of visual acuity under 0.7 in the worst eye were found in 4%, 8.7% and 21.5% respectively in the three age groups ranging from 40 to 49, 50 to 59 and 60 to 69 years and in 54.4% of subjects 70 years old or over.

Prevalence and causes of blindness and low vision in the Casteldaccia Eye Study

In a population-based survey performed on the middle-aged and elderly population of Casteldaccia, Sicily, we found that the prevalence of blindness was 0.47% and the prevalence of low vision 1.22%. Unilateral blindness affected 2.81% of the population and unilateral low vision 4.12%. Visual impairment was much more frequently seen in subjects aged 70 years or more than in younger persons. The main cause of visual impairment was cataract, followed by amblyopia, which was responsible for many cases of unilateral low vision.

Risk factors of ocular hypertension and glaucoma. The Casteldaccia Eye Study

A case-control study was planned as a part of the Casteldaccia Eye Study in order to investigate about risk factors of ocular hypertension and glaucoma. Cases were 44 subjects with glaucoma or intraocular pressure of 24 mm Hg or more. Controls were 220 subjects with intraocular pressure of 20 mm Hg or less and no signs of glaucoma. A number of environmental, behavioral, systemic and ocular variables were studied. Among the others we investigated the following: sunlight exposure, smoking, alcohol intake, pregnancies, systemic hypertension, diabetes, use of corticosteroids, refractive status, anterior chamber depth, lens nuclear sclerosis, iris color and texture. After univariate analysis the use of ocular corticosteroids and antibiotics, myopia, shallow anterior chamber and myopic macular degeneration were associated with ocular hypertension or glaucoma. However, the logistic regression showed that only the use of ocular corticosteroids (odds ratio = 7.79) and the myopia (odds ratio = 5.56) were independently associated.

Topical flurbiprofen in extracapsular cataract surgery: effect on pupillary diameter and iris fluorescein leakage

Recent clinical studies indicate that flurbiprofen, a cyclooxygenase inhibitor, prevents miosis and breakdown of the blood-aqueous barrier during cataract surgery. Yet based on clinical and experimental data, some researchers do not agree that flurbiprofen prevents miosis. We conducted a double-blind clinical study of the effects of topical 0.03% flurbiprofen sodium on intraoperative pupillary diameter and iris fluorescein leakage after extracapsular cataract surgery. In the first phase of the study, 120 patients who had extracapsular cataract extraction with posterior chamber intraocular lens implantation were randomly assigned to receive preoperative topical flurbiprofen or a placebo, with or without intraoperative epinephrine, in addition to the standard regimen. In the second phase, 60 of the 120 patients continued the topical flurbiprofen or placebo for one month postoperatively. Iris fluorescein angiography was performed at the end of the first and the fourth weeks. The results indicate that flurbiprofen was significantly more effective (P < .0001) in maintaining mydriasis during surgery than the placebo. This action was enhanced by intraoperative epinephrine. Flurbiprofen also significantly reduced (P < .001) postoperative iris fluorescein leakage.

Electroretinographic response in WAG/Rij rats after low-intensity cyclic light exposure

In order to investigate the combined influence of age and light, the b-wave and oscillatory potentials (OPs) of the electroretinogram (ERG) were recorded in 1.5-, 7- and 12-month-old WAG/Rij rats, reared under homogenous low-intensity cyclic light exposure. Wistar albino rats of the same ages, reared under the same conditions, served as controls. The b-wave amplitude decreased, and its implicit time increased in the older age groups significantly more in WAG/Rij than in Wistar rats. Statistical analysis indicated that the b-wave amplitude is a more suitable parameter than implicit time in differentiating the ERG variations of one rat strain from the other. The added amplitude of the OPs also decreased in older age groups, but differently from the b wave. This occurred in WAG/Rij rats already at 1.5 months of age.

Photopic ERG components in retinitis pigmentosa

The persistence of a residual flicker electroretinogram 20 Hz response in many cases of retinitis pigmentosa, when the Oscillatory Potentials (OPs) were no longer recordable, led the authors to an investigation by Fourier analysis. The study was carried out in 33 patients affected by different hereditary forms of retinitis pigmentosa revealing recordable 20 Hz flash ERG responses. We applied the Fourier analysis to this ERG response and compared the weight percentage of the first two components to the OP added amplitude. The analysis showed that the 20 Hz flash ERG response contains only the first harmonic in patients with no recordable OPs and both harmonics in patients with recordable OPs. This relationship between OPs and 20 Hz second component, that is possibly related to the activity of inner retina as well as the OPs, can demonstrate an alteration of the inner retina which evolves with distinct electrophysiological features from the ERG photoreceptor impairment.

Intraocular dapiprazole for the reversal of mydriasis after extracapsular cataract extraction with intraocular lens implantation. Part I: Dose-response correlation

Dapiprazole, an alpha-blocking miotic drug, was used intracamerally at the end of extracapsular cataract extraction with posterior chamber intraocular lens (IOL) implantation. The double-blind study included 120 patients divided into four groups of 30 eyes; the groups received balanced salt solution, 0.125%, 0.25%, or 0.5% intraocular dapiprazole after IOL implantation and before suturing. Pupillary diameter recordings were performed immediately before and a few minutes after drug injection and two, four, and eight hours after surgery. The results showed a significant reversal of mydriasis by intraocular dapiprazole, especially with the 0.25% and 0.5% concentrations which did not differ significantly in effectiveness and safety.

Intraocular dapiprazole for the reversal of mydriasis after extracapsular cataract extraction with intraocular lens implantation. Part II: Comparison with acetylcholine

Intraocular dapiprazole for reversing mydriasis during extracapsular cataract extraction with intraocular lens (IOL) implantation has been compared to intraocular acetylcholine. Ninety patients were enrolled in a double-blind study and divided into three groups of 30 eyes; each group received balanced salt solution (control), 0.25% dapiprazole, or 1% acetylcholine. Pupillary diameter recordings were performed immediately before and a few minutes after drug injection, and two, four and eight hours after surgery. Goldmann tonometry was performed the day before and 6 and 24 hours after surgery. Contact endothelial cell count was performed before and one and four months after surgery. The results indicated a slower starting but longer lasting effect with dapiprazole than with acetylcholine and a significant reduction of the postoperative intraoperative pressure rise with both drugs. No significant difference in reduction in the endothelial cell count was seen between dapiprazole and acetylcholine groups and the control group.

Psychophysical and electrofunctional contrast sensitivity in cataractous patients treated with bendazac-lysine salt

The clinical progression of the cataract may be influenced by drugs which reduce the denaturation of lens proteins. One of the most promising drugs is the bendazac-lysine salt. The drug was used in a double-blind study of a group of patients with initial cortical cataract in order to evaluate the changes in visual acuity and contrast sensitivity by means of a psychophysical and an electrophysiological method. After 6 months of treatment with bendazac the mean values of visual acuity showed a statistically significant increase in respect to baseline values, as well as an improvement of the threshold of contrast for most spatial frequencies. In the eyes treated with placebo there was no statistical difference between the visual acuity at baseline and after the treatment, but an increase of the contrast threshold for many spatial frequencies. The treatment with bendazac, when compared to the administration of placebo, leads to a statistically significant improvement of the contrast threshold and induces a global improvement on the visual conditions.

Retinitis pigmentosa and inner retina. Functional study by means of oscillatory potentials of the electroretinogram

The alterations of the inner retina in retinitis pigmentosa have been described in previous papers less often than the external retina alterations, both from the electrophysiological and morphological point of view. The oscillatory potentials (OPs) of the electroretinogram (ERG) are a good tool to investigate the inner part of the retina because of the deep anatomical location of their generators. We studied the photopic OPs in a group of 25 subjects affected with retinitis pigmentosa and compared them with other ERG components to obtain information about the functional damage of the inner retina. The OPs were recordable in 9 patients. No analogies were found with the inheritance modes. No relationship was found between OPs and 20 Hz ERG photopic response which was still present in a consistent number of eyes when OPs were no longer recordable. Such finding can be interpreted as an expression of inner retinal damage paralleling the photoreceptors and retinal pigment epithelium impairment.

Influence of crystalline lens on VEP latency in elderly patients

The study was performed to compare visual evoked potentials of old aphakic and pseudophakic patients (61 to 80 years) with age-matched controls. No differences were found between latencies of the two groups. Thus it seems that increased lens density of old subjects does not influence the processing of the visual stimulus.

L-[3H]lysine binding to rat retinal membrane: I. Quantitative determination and characterization of the binding sites

A saturable reversible binding to membranes from rat retina has been found for L-[3H]lysine. Specific binding is time, temperature and protein concentration-dependent, and shows stereospecificity. The best computer fits of the experimental data are obtained with a receptor model based on two independent binding sites, of which only one site with a Kd value of 229.4 +/- 14.23 nM and a Bmax of 2.04 +/- 0.11 pmol/mg protein could be characterized satisfactorily. Several compounds included putative neurotransmitters have moderate or no affinity for L-lysine binding sites. A different pattern of distribution of L-[3H]lysine binding sites is observed among various regions of the brain, with the highest density in the occipital cortex, and the lowest density in ponsmedulla. The existence of binding sites in rat retinal membranes for L-lysine, as well as in the areas involved in the visual pathway, suggests a role for this amino acid in the physiological mechanism of the visual function.

L-[3H]lysine binding to rat retinal membrane: II. Effect of kainic acid, D,L-alpha-aminoadipic acid, iodoacetic acid, and modification by dark-exposure

The rat retina and the different brain regions contain membranes sites that bind L-lysine in the nanomolar range. These binding sites undergo changes in different experimental conditions, thus: intraocular injection of kainic acid induces a reduction of the density of L-lysine binding sites, D,L-alpha-aminoadipic acid injected into the eye enhances both kinetic parameters (Bmax and Kd) of L-[3H]lysine binding sites, the intraperitoneal injection of iodoacetic acid decreases the sensitivity for its ligand binding sites, and the exposure to darkness of the rats reduces L-[3H]lysine binding in the retina, thalamus, hypothalamus and superior colliculus, but not in the occipital cortex; such a decrease appears to be characterized, at least in the retina, by a lower sensitivity of the binding sites for L-lysine after the exposure to darkness. The results show that L-lysine binding sites are located on kainic acid-sensitive cells and can be involved in the physiological mechanism of vision.