Prevalence and antibiotic resistance in bacterial isolates of dogs with ulcerative keratitis in São Paulo State, Brazil.

OBJECTIVE: Identify microorganisms present in canine eyes affected by ulcerative keratitis and assess its resistance profile to available antimicrobial drugs. METHODS: Samples were collected from 88 canine eyes that exhibited ulcerative keratitis. They were identified using MALDI-TOF and subjected to antimicrobial susceptibility testing by disk diffusion. RESULTS: Among the assessed subjects, brachycephalic dogs accounted for 74.48% (50/83) of the evaluated canines. Among the 88 evaluated eyes, 90.9% (80/88) showed positive cultures, with 11.33% (10/88) of the samples isolating more than one species of bacteria. Of all bacterial isolates identified (90), Gram-positive bacteria accounted for 63.33% (57/90), while Gram-negative bacteria constituted 36.66% (33/90), with predominance of Staphylococcus spp. at 35.55% (32/90) being, Staphylococcus pseudintermedius at 68.75% (22/32), and Pseudomonas aeruginosa at 15.55% (14/90), respectively. Staphylococcus spp. exhibited resistance to penicillin (89.29%), sulfadiazine and trimethoprim (60.71%), and tetracycline (67.86%), while doxycycline (88.89%), cefotaxime (85.71%), chloramphenicol (82.14%), gentamicin, and moxifloxacin (78.57%) showed the highest sensitivity rates. Pseudomonas aeruginosa displayed sensitivity (100%) to gentamicin and imipenem, and resistance (8.33%) to norfloxacin, ciprofloxacin, and cefepime. Similarly, the Enterobacteriaceae family showed higher sensitivity to amikacin and gentamicin (88.89%), imipenem (88.24%), and levofloxacin (87.5%), with pronounced resistance to amoxicillin-clavulanate (50%) and cefazolin (47.06%). This highlights multiresistance in 23.33% (21/90) of the isolates. CONCLUSIONS: The most isolated species in canine ulcerative keratitis are S. pseudintermedius and P. aeruginosa. However, other species were also isolated, demonstrating diversity in ocular microbiota infection. There is a high-rate multidrug resistance associated with canine ulcerative keratitis. Nevertheless, these strains exhibited sensitivity to antimicrobials commonly used in veterinary ophthalmology.

Accuracy of ARFI elastography in the differentiation of cataract stages in dogs / Acurácia da elastografia ARFI na diferenciação dos estágios da catarata em cães

Objective was to evaluate the accuracy of elastography in the differentiation between normal and cataract lenses One hundred forty-five eyes of 98 dogs were divided into groups according to cataract stage. Forty-twoeyes were submitted to phacoemulsification. Biometric parameters, echogenicity and echotexture patterns of the anterior, posterior and vitreous chambers, lens and retina-choroid-sclera complexes were evaluated by ocular ultrasound in modes A and B. Deformability, and color (blue color = indicated less rigid structures, color red = more rigid structures) of the lenses were evaluated by the elastogram. The shear wave velocity (SWV; m/s) was calculated in three regions of the lens, both in the cortex and in the nucleus. The SWV of nucleus was statistically different between the normal lenses and with cataracts, and between the stages of cataract (P<0.001). Healthy lenses and incipient cataracts had a more rigid nucleus. Mature cataracts presented lowest nuclear rigidity (P<0.001). On cortical region the SWV was significantly higher (P<0.01) in intumescent and incipient cataracts. SWV less than 2.67m/s indicates cataract with a sensitivity of 72% and specificity of 94%. Values lower than 2.23m/s suggest mature cataract, with sensitivity of 71% and specificity of 76%. SWV greater than 2.66 m/s are associated with normal lenses or incipient cataract, presenting sensitivity of 94% and specificity of 84%. Qualitative method allowed differentiation between healthy and affected lenses and the classification of evolutionary stages. There was a correlation between the degree of stiffness of lens in cortical and nuclear regions (p=00165, r=0.37) and between the balanced saline solution quantitative and surgical time (P<0.01, r=0.73). Degree of stiffness of lens did not correlate with parameters of phacoemulsification. Elastographic proved feasible for evaluating the lens of dogs, characterizing the types of cataracts, and demonstrating increased stiffness of the diseased lenses.(AU)

O objetivo foi avaliar a precisão da elastografia na diferenciação entre lentes normais e de catarata. Cento e quarenta e cinco olhos de 98 cães foram divididos em grupos de acordo com o estágio de maturação da catarata. Quarenta e dois olhos foram submetidos à facoemulsificação. Parâmetros biométricos, ecogenicidade e padrões de ecotextura das câmaras anterior, posterior e vítrea, lente e complexos retina-coróide-esclera foram avaliados por ultrassonografia ocular nos modos A e B. A deformabilidade e a coloração (cor azul = indicou estruturas menos rígidas, cor vermelha = estruturas mais rígidas) das lentes foram avaliadas pelo elastograma. A velocidade da onda de cisalhamento (SWV; m/s) foi calculada em três regiões da lente, tanto no córtex quanto no núcleo. A SWV do núcleo foi estatisticamente diferente entre as lentes normais e com catarata e entre os estágios da catarata (P<0,001). Lentes saudáveis e cataratas incipientes tinham um núcleo mais rígido. Cataratas maduras apresentaram menor rigidez nuclear (P<0,001). Na região cortical, a SWV foi significativamente maior (P<0,01) nas cataratas intumescentes e incipientes. Uma SWV menor que 2,67m/s indica catarata com sensibilidade de 72% e especificidade de 94%. Valores inferiores a 2,23m/s sugerem catarata madura, com sensibilidade de 71% e especificidade de 76%. Uma SWV superior a 2,66m/s está associada à catarata normal ou incipiente, apresentando sensibilidade de 94% e especificidade de 84%. O método qualitativo permitiu a diferenciação entre lentes normais de olhos saudáveis e afetadas e a classificação dos estágios evolutivos. A elastografia se mostrara uma ferramenta viável para avaliar as lentes de cães, caracterizando os tipos de catarata e demonstrando maior rigidez das lentes doentes.(AU)

Accuracy of ARFI elastography in the differentiation of cataract stages in dogs

ABSTRACT: Objective was to evaluate the accuracy of elastography in the differentiation between normal and cataract lenses One hundred forty-five eyes of 98 dogs were divided into groups according to cataract stage. Forty-twoeyes were submitted to phacoemulsification. Biometric parameters, echogenicity and echotexture patterns of the anterior, posterior and vitreous chambers, lens and retina-choroid-sclera complexes were evaluated by ocular ultrasound in modes A and B. Deformability, and color (blue color = indicated less rigid structures, color red = more rigid structures) of the lenses were evaluated by the elastogram. The shear wave velocity (SWV; m/s) was calculated in three regions of the lens, both in the cortex and in the nucleus. The SWV of nucleus was statistically different between the normal lenses and with cataracts, and between the stages of cataract (P 0.001). Healthy lenses and incipient cataracts had a more rigid nucleus. Mature cataracts presented lowest nuclear rigidity (P 0.001). On cortical region the SWV was significantly higher (P 0.01) in intumescent and incipient cataracts. SWV less than 2.67m/s indicates cataract with a sensitivity of 72% and specificity of 94%. Values lower than 2.23m/s suggest mature cataract, with sensitivity of 71% and specificity of 76%. SWV greater than 2.66 m/s are associated with normal lenses or incipient cataract, presenting sensitivity of 94% and specificity of 84%. Qualitative method allowed differentiation between healthy and affected lenses and the classification of evolutionary stages. There was a correlation between the degree of stiffness of lens in cortical and nuclear regions (p=00165, r=0.37) and between the balanced saline solution quantitative and surgical time (P 0.01, r=0.73). Degree of stiffness of lens did not correlate with parameters of phacoemulsification. Elastographic proved feasible for evaluating the lens of dogs, characterizing the types of cataracts, and demonstrating increased stiffness of the diseased lenses.

RESUMO: O objetivo foi avaliar a precisão da elastografia na diferenciação entre lentes normais e de catarata. Cento e quarenta e cinco olhos de 98 cães foram divididos em grupos de acordo com o estágio de maturação da catarata. Quarenta e dois olhos foram submetidos à facoemulsificação. Parâmetros biométricos, ecogenicidade e padrões de ecotextura das câmaras anterior, posterior e vítrea, lente e complexos retina-coróide-esclera foram avaliados por ultrassonografia ocular nos modos A e B. A deformabilidade e a coloração (cor azul = indicou estruturas menos rígidas, cor vermelha = estruturas mais rígidas) das lentes foram avaliadas pelo elastograma. A velocidade da onda de cisalhamento (SWV; m/s) foi calculada em três regiões da lente, tanto no córtex quanto no núcleo. A SWV do núcleo foi estatisticamente diferente entre as lentes normais e com catarata e entre os estágios da catarata (P 0,001). Lentes saudáveis e cataratas incipientes tinham um núcleo mais rígido. Cataratas maduras apresentaram menor rigidez nuclear (P 0,001). Na região cortical, a SWV foi significativamente maior (P 0,01) nas cataratas intumescentes e incipientes. Uma SWV menor que 2,67m/s indica catarata com sensibilidade de 72% e especificidade de 94%. Valores inferiores a 2,23m/s sugerem catarata madura, com sensibilidade de 71% e especificidade de 76%. Uma SWV superior a 2,66m/s está associada à catarata normal ou incipiente, apresentando sensibilidade de 94% e especificidade de 84%. O método qualitativo permitiu a diferenciação entre lentes normais de olhos saudáveis e afetadas e a classificação dos estágios evolutivos. A elastografia se mostrara uma ferramenta viável para avaliar as lentes de cães, caracterizando os tipos de catarata e demonstrando maior rigidez das lentes doentes.

Reduction in Histone H3 Acetylation and Chromatin Remodeling in Corneas of Alloxan-Induced Diabetic Rats.

PURPOSE: To evaluate acetylation of histone H3, chromatin remodeling, nuclear size and shape, DNA ploidy, and distribution of nucleolus organizing regions (NORs) in corneal epithelial and stromal cells of diabetic and nondiabetic rats. METHODS: Diabetes was induced by a single intraperitoneal injection of alloxan. All diabetic rats (n = 20) included in the study had 4 weeks of moderate-to-severe hyperglycemia (plasma glucose levels >400 mg/dL). Acetylated histone H3 levels were quantified in corneal tissue using a colorimetric assay. Chromatin remodeling, nuclear sizes (area/perimeter) and shapes (circularity), and DNA ploidies were evaluated from Feulgen-stained tissue sections using video image analysis. Distributions of NORs were studied in tissue sections impregnated with silver ions. Ophthalmic clinical parameters, including corneal sensitivity, were investigated. Twenty nondiabetic rats were used as controls. RESULTS: Acetylation of histone H3 was reduced in the corneas of the diabetic rats. Nuclei in corneal epithelial cells of diabetic rats compacted chromatin, increased in size, modified their shapes, and elevated DNA ploidy. The only nuclear change observed in the corneal stromal cells of diabetic rats was chromatin decompaction. The size of the silver-stained NOR did not differ between the study samples. The corneal sensitivity in diabetic rats was 51.8% lower than that in nondiabetic rats. CONCLUSIONS: The results of this study show that alloxan-induced diabetes altered the histone H3 acetylation pattern and compromised the chromatin supraorganization in corneal tissue/cells. Continued research is needed to understand the clinical and morphofunctional significance of changes in corneal cell nuclei of diabetic individuals.

Ophthalmic parameters in adult lowland paca (Cuniculus paca) raised in captivity.

OBJECTIVE: To investigate the ophthalmic parameters of lowland pacas, including the anatomic features, tear production, intraocular pressure, central corneal thickness, and morphology of the corneal endothelium. ANIMALS STUDIED: Thirteen adult, anesthetized Cuniculus paca. PROCEDURE: Eyes were evaluated using slit-lamp biomicroscopy, the Schirmer tear test I, digital applanation tonometry, binocular indirect ophthalmoscopy, and noncontact specular microscopy. RESULTS: The biomicroscopy findings showed blue/brown pigmented bulbar conjunctivae, well-developed cilia (only in the upper eyelid margin), superior and inferior lacrimal puncta, brown irides, round pupils, and vestiges of the nictitating membrane. The results of the Schirmer tear test I revealed (mean ± SD) a lacrimation rate of 4.10 ± 0.44 mm/min. The intraocular pressure was 6.34 ± 0.43 mmHg. Central corneal thickness measured by specular microscopy was 0.35 ± 0.01 mm. The mean values of density, hexagonality, and the area of the endothelial cells were 2083.15 ± 42.47 cells/mm2 , 67.07 ± 3.30%, and 486.30 ± 9.56 µm2 , respectively. CONCLUSIONS: The ocular parameters defined in this study may be used for reference in future studies and might also contribute to therapeutic approaches appropriate to this species.

Supra-organization and optical anisotropies of the extracellular matrix in the amniotic membrane and limbal stroma before and after explant culture.

In this research we evaluated the supramolecular organizations and the optical anisotropical properties of the de-epithelialized human amniotic membrane and rabbit limbal stroma, before and after explant culture. Birefringence, monochromatic light spectral absorption and linear dichroism of the main extracellular matrix biopolymers, that is, the fibrillar collagens and proteoglycans, were investigated by polarized light microscopy combined with image analysis. Our results demonstrated that the culture procedure-induced stimuli altered the supra-organizational characteristics (in terms of collagens/proteoglycans spatial orientation and ordered-aggregational state) of the amniotic and limbal extracellular matrix, which led to changes in optical anisotropical properties.