Olfactomedin-like 2 A and B (OLFML2A and OLFML2B) expression profile in primates (human and baboon)

BACKGROUND: The olfactomedin-like domain (OLFML) is present in at least four families of proteins, including OLFML2A and OLFML2B, which are expressed in adult rat retina cells. However, no expression of their orthologous has ever been reported in human and baboon. OBJECTIVE: The aim of this study was to investigate the expression of OLFML2A and OLFML2B in ocular tissues of baboons (Papio hamadryas) and humans, as a key to elucidate OLFML function in eye physiology. METHODS: OLFML2A and OLFML2B cDNA detection in ocular tissues of these species was performed by RT-PCR. The amplicons were cloned and sequenced, phylogenetically analyzed and their proteins products were confirmed by immunofluorescence assays. RESULTS: OLFML2A and OLFML2B transcripts were found in human cornea, lens and retina and in baboon cornea, lens, iris and retina. The baboon OLFML2A and OLFML2B ORF sequences have 96% similarity with their human's orthologous. OLFML2A and OLFML2B evolution fits the hypothesis of purifying selection. Phylogenetic analysis shows clear orthology in OLFML2A genes, while OLFML2B orthology is not clear. CONCLUSIONS: Expression of OLFML2A and OLFML2B in human and baboon ocular tissues, including their high similarity, make the baboon a powerful model to deduce the physiological and/or metabolic function of these proteins in the eye.

Conjuntivites / Conjunctivites

Esta revisão visa contemplar os diferentes aspectos clínicos, etiológicos, diagnósticos e terapêuticos das inflamações conjuntivais agudas mais comuns. Tem o objetivo de guiar o raciocínio clínico e manejo diante de um caso de conjuntivite na emergência, assim como atentar para os principais achados de gravidade que requerem avaliação imediata do caso por um especialista.

This chapter aims to review the main clinical, etiologic, diagnostic and treatment topics of the most common acute conjunctival inflammation. The goal is to guide the clinical management of conjunctivitis in the emergency room, as well as to recognize the main findings of gravity that require immediate evaluation by an expert.

Circulating Total Glutathione in Normal Tension Glaucoma Patients: Comparison with Normal Control Subjects

PURPOSE: Oxidative stress plays a critical role in the pathogenesis of glaucoma. Glutathione is a major antioxidant molecule present in intracellular or extracellular space. Herein, we aimed to examine circulating glutathione level in normal tension glaucoma (NTG), which comprises the largest proportion of glaucoma disease in the Korean population. METHODS: Nineteen NTG patients (NTG group) and 30 age- and gender-matched normal control subjects (control group) were included. Antecubital venous puncture was performed between 8 and 10 o'clock in the morning to obtain a 4 mL venous blood sample. Total glutathione level was measured by the spectrophotometric method at 412 nm. Correlation of total glutathione level with mean deviation and pattern standard deviation from the Humphrey visual field test was analyzed in the NTG group. RESULTS: Total glutathione level in circulating blood was 524.02 +/- 231.09 nmol and 586.06 +/- 156.08 nmol in the NTG group and the control group, respectively. The difference between these values was not statistically significant (p = 0.121, F = 2.212). Age had no significant effect on circulating total glutathione level in either the NTG group (p = 0.171, r = -0.328) or the control group (p = 0.380, r = -0.166). In the NTG group, circulating total glutathione level had no significant relationship with mean deviation (p = 0.226, F = 1.636) and pattern standard deviation (p = 0.200, F = 1.766) after correcting for age and gender. CONCLUSIONS: In NTG patients, circulating total glutathione levels were not different compared to those of normal subjects.

A comparative study of iron-related metabolic parameters in the eye of three animal species

In order to obtain a wider perspective of iron homeostasis in the eye, a comparative study was undertaken of several iron-related parameters (Total Iron, TI; Total Iron Binding Capacity, TIBC; Transferrin, Tf; and saturation of Tf) both in blood serum and in ocular tissues (lens, cornea, iris-ciliary body, retina) and fluids (vitreous body, aqueous humor) of several animal species (pig, cow and rat). The relative degree of oxidative stress of tissues and fluids was evaluated based on the criteria that high values of TI and Tf saturation, and low values of TIBC and Tf, would promote iron-related oxidative stress. The inclusion of both diurnal (pig, cow) and nocturnal (rat) animal species in this comparative work provided the opportunity to explore if iron homeostasis parameters are in some way influenced by the higher oxidative stress level expected in animals with diurnal living habits. This project involved also the design of new and very sensitive methods of analyses, given the fact that in many cases very small amounts of sample (i.e., aqueous humor), and/or low concentration of analytes (i.e., transferrin) are available. All results were expressed as concentration relative to mg protein as determined with the Bradford method (microplate assay). When analyzing TI/TIBC it was possible to define a loosely bound iron pool (LBIP) in ocular tissues that was proportional to the degree of vascularization of the tissues analyzed. The comparison of iron related parameters patterns within the eye and among species allowed us to reach the following conclusions: (1) The aqueous humor and vitreous body of cow and pig exhibited highest concentration of Tf and a very low saturation of Tf, while the lowest value of Tf was detected in all species in the lens; (2) TI showed the tendency to be highest in the vitreous body of cow and pig, and lowest in the lens of all three species. The very low iron concentration in the lens may effectively counteract the...

Pattern of Wnt ligand expression during chick eye development

The dorsoventral axis of the eye is determined prior to optic cup invagination. A variety of signaling pathways have been implicated in the maintenance of the optic dorsoventral axis, including, but not limited to, bone morphogenetic protein 4, Sonic Hedgehog and retinoic acid. Here, we investigated the possible contribution of Wnt ligands to the establishment or maintenance of the optic axis by analyzing their expression pattern during early chick optic development. We performed in situ hybridization of Wnt-1, Wnt-3a, Wnt-4, and Wnt-5a during the optic vesicle, early optic cup and established optic cup stages and focused our analysis on the optic region. Our data showed that Wnt-5a, but none of the others, is expressed in the dorsal region of the eye starting from the Hamburger and Hamilton stage 14 (HH14). These results are supported by cryosections of the labeled optic region, which further reveal that Wnt-5a is expressed only in the dorsal retinal pigmented epithelium. Thus, we propose that Wnt-5a is a marker for dorsal retinal pigmented epithelium in chick embryos from HH14 to HH19.

GAL4 causes developmental defects and apoptosis when expressed in the developing eye of Drosophila melanogaster

The UAS/GAL4 ectopic expression system is widely used in Drosophila melanogaster for the overexpression of transgenes. This system operates under the assumption that the yeast transcription factor, GAL4, is inactive in D. melanogaster. Thus, GAL4 can be expressed under the control of D. melanogaster -specific promoters with little effect upon the organism. We have shown that expression of GAL4 in the developing eye under the control of the glass multiple reporter (GMR) promoter element does have an effect on eye development. Although GMR-GAL4 heterozygotes appear normal when raised at 25 degrees C, the homozygotes have a highly disorganized ommatidial array. In addition, the levels of apoptosis in the third-instar larval eye imaginal disc (where GAL4 is expressed) are slightly higher in GMR-GAL4 heterozygotes, and much higher in GMR-GAL4 homozygotes when compared to wild type discs. The morphological eye defects caused by GMR-GAL4 are significantly enhanced when flies are raised at 29 degrees C (presumably due to the higher activity of GAL4 at this temperature); however, the levels of apoptosis appear to be similar at these two temperatures. Taken together, these data suggest that GAL4 can have adverse effects on D. melanogaster development, especially at high expression levels. In addition, GAL4 appears to induce apoptosis even in the absence of any visible morphological defects. Thus, despite the benefits of the UAS/GAL4 ectopic expression system, one must use caution in the design and interpretation of experiments

Transthyretin (prealbumin) in eye structures and variation of vitreous-transthyretin in diseases.

PURPOSE: To evaluate the presence of transthyretin (TTR, prealbumin) a protein which binds retinol to retinol-binding protein in various ocular tissues and to study its quantitative changes in the vitreous humor in various diseases. METHOD: Estimation of TTR was done by electrophoresis of 10 mg protein in each sample of tears, aqueous humor, vitreous, retina, and lens by an Imaging Densitometer using prealbumin as the standard. RESULTS: TTR was present in all the eye structures except the lens and tear. The retina and the vitreous had relatively higher amounts of TTR compared with aqueous. The identity of TTR was confirmed by immuno-electrophoresis using anti-human TTR. Two bands in SDS electrophoresis revealed that this protein is a heterodimer. There was a significant decrease in vitreous TTR in diabetes with hypertension and increase in one case each of diabetes with hypertension associated with leukaemia or carcinoma with hepato-splenomegaly. CONCLUSION: Vitreous TTR is probably from retina and retinal pigment epithelium. The level of vitreous TTR is likely to have diagnostic significance in some retinal diseases.