Comparative evaluation of corneal and limbal epithelial thickness in brachycephalic dogs with and without corneal diseases using spectral domain optical coherence tomography.

OBJECTIVE: To evaluate alterations in epithelial thickness during corneal degeneration, corneal pigmentation, and additional features observed through spectral-domain optical coherence tomography (SD-OCT) in brachycephalic dogs. ANIMALS AND PROCEDURES: The study used 55 eyes from 49 brachycephalic dogs that underwent OCT-containing ophthalmic examinations. The examined eyes were classified into corneal degeneration, corneal pigmentation, and normal groups according to corneal lesions. For each eye, corneal epithelial thickness (CET) in the central cornea and maximum limbal epithelial thickness (maxLET) in 4 quadrants of limbus (superior, inferior, nasal, and temporal) were measured from OCT images. Additional abnormal findings on OCT images, including irregular epithelium, subepithelial hyperreflectivity, and conjunctivochalasis, were also recorded. RESULTS: The corneal degeneration group had significantly thinner nasal and temporal maxLETs than that of the normal group (p < .001). In the central corneal OCT image of the corneal degeneration group, an irregular epithelium was observed in 70.6% and subepithelial hyperreflectivity in 82.4%, both of which were significantly higher than the normal group (p < .001). In a comparative analysis, the nasal, temporal, and inferior maxLETs were significantly thinner in the corneal pigmentation group than those in the normal group (p < .001, p < .001, and p = .01, respectively). CONCLUSIONS: Morphological changes in the limbal epithelium were observed in dogs with corneal degeneration and corneal pigmentation. LET reduction could be associated with their pathogenesis and would be valuable as an additional parameter for corneal diseases.

Treatment of immune-mediated keratitis (IMMK) in dogs with immunosuppressants observed with spectral domain optical coherence tomography (SD-OCT).

Two dogs presented with bilateral pattern-forming corneal opacity. Treatment with topical immunosuppressants was initiated after a complete ophthalmic examination. The response to treatment was assessed by analyzing serial images using slit-lamp biomicroscopy and spectral domain optical coherence tomography (SD-OCT). Both dogs responded to topical immunosuppressants; however, the lesions recurred once the treatment was abated or withdrawn. The most effective immunosuppressant in both dogs was 0.03% tacrolimus ointment. Early and continuous treatment with topical immunosuppressants may be necessary to improve corneal clarity and prevent scarring. SD-OCT could provide useful structural information regarding presumed immune-mediated keratitis and aid in monitoring treatment response.

Two different procedures for managing ocular melanosis presenting scleral pigmentation with glaucoma in a Shih-Tzu dog: A case of definitive diagnosis in one eye and a presumed diagnosis in the contralateral eye.

A 12-year-old castrated male Shih-Tzu dog was referred for uncontrolled glaucoma and uveitis with highly pigmented sclera, in both eyes (OU). On ophthalmic examination, the menace response, dazzle reflex and pupillary light reflex were negative OU. The intraocular pressure was 27 mmHg in the right eye (OD) and 70 mmHg in the left eye (OS) despite the administration of antiglaucoma eyedrops. Ultrasound biomicroscopy revealed a closed ciliary cleft OU. Ocular ultrasonography revealed hyperechoic materials in the vitreous OU and retinal detachment OS. When presented for recheck, an extensive malacic corneal ulcer was observed OS. To relieve pain in the blind eyes, enucleation OS and pharmacologic ciliary body ablation (CBA) OD were performed. Histologically, ocular melanosis, which is an inherited disease in the Cairn Terrier breed, was identified in the enucleated eye. The uvea was heavily pigmented. The iris and ciliary body were mildly distorted by a single population of large, round, nonneoplastic cells with pigmented cytoplasm. There was no evidence of an intraocular mass or metastasis before and after intravitreal CBA. This is the first report of bilateral ocular melanosis in a Shih-Tzu dog. Ocular melanosis is a possible differential diagnosis for globe presenting scleral pigmentation with glaucoma in even non-Cairn Terrier breeds and pharmacologic CBA could be considered as a treatment for ocular melanosis with end-stage glaucoma.

Retrospective study of postoperative intraocular pressure and complications in phacoemulsification combined with endoscopic cyclophotocoagulation and phacoemulsification alone in dogs.

BACKGROUND: Long-term comparative data of phacoemulsification combined with endoscopic cyclophotocoagulation (phaco-ECP) versus phacoemulsification (phaco) alone in dogs are rare. OBJECTIVES: To investigate the effects of ECP on postoperative intraocular pressure (IOP) and complications after phaco in dogs with normal IOP. METHODS: Medical records of IOP, conjunctival hyperemia, corneal edema, aqueous flare, posterior synechia, intraocular fibrin, and posterior capsule opacification (PCO) formation in 15 canine eyes that underwent phaco-ECP and 36 eyes that underwent phaco alone were evaluated retrospectively. ECP was applied when either the iridocorneal angle or the ciliary cleft was narrow or closed. RESULTS: The IOP of the phaco-ECP group persisted within the normal range postoperatively. The phaco-ECP group had a shorter period of dorzolamide use than did the phaco group. PCO was formed earlier in the phaco-ECP group than in the phaco group. The phaco-ECP group showed more severe corneal edema than the phaco group at every follow-up visit. Posterior synechia was more severe in the phaco-ECP group than in the phaco group from two weeks until the last follow-up. CONCLUSIONS: Although ECP might cause more postoperative complications such as corneal edema and posterior synechia, it could effectively reduce the incidence of IOP increase after phaco in dogs with a high risk of postoperative glaucoma.

Assessment of corneal and limbal epithelial thickness by spectral-domain optical coherence tomography in brachycephalic and non-brachycephalic dogs.

OBJECTIVE: To investigate the variance in corneal epithelial thickness (CET) and limbal epithelial thickness (LET) according to the age and skull type by using spectral-domain optical coherence tomography (SD-OCT) in normal dogs. ANIMALS AND PROCEDURES: This study used an eye each from 46 dogs (24 brachycephalic and 22 non-brachycephalic dogs) assessed to have clear corneas. Each dog was classified according to age into groups 1 (0-5 years), 2 (6-10 years), and 3 (>11 years). OCT imaging was performed on the central cornea for CET and perpendicular to the quadrant of the limbus for LET. The average of the maximum LET (maxLET) value was measured in four eye quadrants. RESULTS: Corneal epithelial thickness was not significantly different according to age in brachycephalic and non-brachycephalic dogs. Visualization of the limbal invagination was better when the maxLET was thick. Nasal and temporal maxLETs were significantly thicker than superior and inferior maxLETs in non-brachycephalic dogs. In brachycephalic dogs, there was a significant decrease in nasal maxLET with age (rs  = -0.489, p = .015). Significant differences between brachycephalic and non-brachycephalic dogs were observed in nasal maxLET (p = .024) and temporal maxLET (p = .011). CONCLUSIONS: Invagination was better visualized in the nasal and temporal limbal quadrants of non-brachycephalic dogs compared with brachycephalic dogs, and the maxLETs of the regions were thicker than those of the brachycephalic dogs. CET and LET measurements using SD-OCT can help in clinical assessment and research on ocular surface diseases in dogs.

Evaluation of ocular surface parameters in dogs with and without meibomian gland dysfunction.

BACKGROUND: Interest in meibomian gland dysfunction (MGD) is growing in veterinary medicine. However, research on MGD in dogs is lacking. The aims of this study were to compare the interferometry grades, tear meniscus height (TMH) and non-invasive tear break-up time (NIBUT) grades between dogs with and without MGD. METHODS: Routine ophthalmic examination, interferometry, NIBUT assessment, TMH measurement and meibography were performed. Age and Schirmer tear test-1 (STT-1) results were compared between the control and MGD groups using Student's t-test. Interferometry grades, NIBUT grades and TMH were compared between the two groups using Mann-Whitney U-test. RESULTS: There was no significant difference in age between the two groups (p = 0.279). STT-1 (p = 0.024), interferometry (p = 0.004) and NIBUT grades (p = 0.012) were significantly lower in the MGD group than in the control group. No significant difference in TMH values (p = 0.587) was observed between the two groups. While the control group included 18 and seven eyes in meiboscore 0 and 1, in MGD group, 12, eight, five and three eyes were included in meiboscore 0, 1, 2 and 3, respectively. CONCLUSIONS: Low interferometry and NIBUT grades were associated with MGD, suggesting decreased meibum and disrupted tear film quality. TMH did not differ between the two groups. Meibography could aid in the diagnosis of MGD in severe cases, although it could not detect early MGD in the dogs in this study.

Quantification of tear glucose levels and their correlation with blood glucose levels in dogs.

BACKGROUND: No previous studies have quantified tear glucose (TG) levels in dogs or compared changes in TG and blood glucose (BG) concentrations. OBJECTIVE: To quantify TG concentration and evaluate its correlation with BG level in dogs. METHODS: Twenty repetitive tests were performed in alternate eyes of four dogs, with a minimum washout period of 1 week. Tears and blood were collected at 30-min intervals with successive glucose injections (1 g/kg) every 30 min. Cross-correlations of BG and TG levels were assessed. The delay and association between TG and corresponding BG levels were analysed for each dog; samples were collected at 5-min intervals. The tears were collected using microcapillary tubes. Collected tears and blood were analysed for glucose concentration using a colorimetric assay and commercially available glucometer, respectively. RESULTS: The average baseline BG and TG levels were 4.76 ± 0.58 and 0.39 ± 0.04 mmol/L, respectively. Even with highly fluctuating BG levels, a significant cross-correlation coefficient (r = 0.86, p < 0.05) was observed between changes of BG and TG levels. The delay time between BG and TG levels was 10 min. On average, BG levels were 16.34 times higher than TG levels. There was strong correlation between BG and TG levels (rs  = 0.80, p < 0.01). Significant differences in TG concentrations between normoglycaemia, mild hyperglycaemia, and severe hyperglycaemia were found (p < 0.05). CONCLUSIONS: Canine TG concentrations have not been quantified previously. Our findings suggest preliminary data for future research on TG levels in dogs and show TG measurement could be used to screen for diabetes mellitus in dogs.

Comparison of iridocorneal angle parameters measured by spectral domain optical coherence tomography and ultrasound biomicroscopy in dogs.

OBJECTIVE: To compare the measurements of iridocorneal angle parameters between spectral domain optical coherence tomography (SD-OCT) and ultrasound biomicroscopy (UBM) in dogs. ANIMALS STUDIED AND PROCEDURES: A total of 47 eyes of dogs were scanned at the temporal limbus using SD-OCT and UBM. Iridocorneal angle (ICA) and angle opening distance (AOD) were measured from the obtained images accordingly. The intra-observer and inter-observer reproducibility were evaluated using the intraclass correlation coefficient. To evaluate intra-observer reproducibility, measurements of the first and second grading from the first examiner were compared. To evaluate inter-observer reproducibility, measurements between the two examiners were compared. Agreement between ICA and AOD for SD-OCT and UBM was evaluated using Bland-Altman plots. RESULTS: In the first grading, the mean ICA and AOD for SD-OCT were 31.4 ± 6.4° and 641.4 ± 270.8 µm, respectively. The mean ICA and AOD for UBM were 32.0 ± 4.8° and 700.4 ± 238.8 µm, respectively. For ICA and AOD measurements, intra-observer reproducibility was excellent for both devices, whereas inter-observer reproducibility was excellent for SD-OCT and good for UBM. The mean difference in ICA between SD-OCT and UBM was 0.6° with a limit of agreement (LoA) span of 18.9°. The mean difference in AOD between SD-OCT and UBM was 58.9 µm with a LoA span of 804.4 µm. CONCLUSIONS: Spectral domain optical coherence tomography is an effective non-contact imaging modality for the evaluation of canine iridocorneal angle parameters in a clinical setting. Reproducibility of measurements obtained is comparable or superior to UBM, but values obtained by SD-OCT and UBM for AOD are not interchangeable between devices.

The feasibility of clinical evaluation for anterior uveitis through spectral-domain optical coherence tomography in dogs.

OBJECTIVE: To evaluate the clinical application of spectral-domain optical coherence tomography (SD-OCT) for anterior uveitis in dogs. Animals and procedures Client-owned dogs presenting with anterior uveitis and clinically healthy dogs were enrolled in this study. Included eyes were divided into 5 groups by flare grade and 3 groups by cell grade through slit-lamp biomicroscopy. Each eye was examined using SD-OCT following slit-lamp biomicroscopy. The ratio of aqueous signal intensity to air signal intensity, which is called the aqueous-to-air relative intensity (ARI) index, was used to evaluate the flare grade. Cell number, central corneal thickness (CCT), and the presence of keratic precipitates (KPs) were analyzed on SD-OCT. The OCT parameters, including ARI index, cell number, and CCT, were compared to the slit-lamp clinical flare and cell grade. RESULTS: Thirty-six eyes with anterior uveitis and 27 healthy eyes were enrolled. The ARI index showed a significant correlation with clinical flare grade (rs  = 0.811, p < .001). In multiple regression analysis, the ARI index and CCT showed a significant negative correlation (r = -0.258, p = .044). The number of cells on SD-OCT significantly increased with cell grade on slit-lamp biomicroscopy (rs  = 0.653, p < .001). The clinical flare grade and CCT were significantly correlated in the partial correlation analysis after controlling for age (partial correlation coefficient = 0.471, p = .002). KPs were observed in 61% of the eyes with flare using SD-OCT (22/36 eyes). CONCLUSIONS: Spectral-domain optical coherence tomography could provide quantitative information, including the ARI index, cell counts, and CCT in dogs. SD-OCT is an auxiliary modality for slit-lamp biomicroscopy when evaluating anterior uveitis in dogs.

Efficacy of topical rocuronium bromide as a mydriatic agent in domestic pigeons (Columba livia).

This study was conducted to investigate the efficacy of rocuronium bromide as mydriatic agent in domestic pigeons (Columba livia). This study was done in two phases. In the first phase, rocuronium bromide (0.20 mg/20 µl) was topically instilled to the right eye (OD) of eight domestic pigeons. Pupil diameter was measured before instillation (T0), and at 5 (T05) and 10 (T10) min after instillation, and every 10 min thereafter until 160 (T160) min. Pupillary light reflex (PLR) was assessed using a scoring system at the same time points. In the second phase, the same dosage was instilled twice in the span of 10 min into both eyes (OU) of four pigeons (eight eyes). Measurements were done accordingly. The iris color in the first phase were: gravel, pearl and bull eye. All irises in the second phase were bull eye. Mydriasis were observed in 6/8 (75%) pigeons in the first phase. Maximal mydriasis was observed at T30 (mean pupil diameter=4.62 ± 0.13 mm). Pupil diameter in the treated eye was significantly different from contralateral eye and from T0 since T05 (P=0.017 and P=0.006, respectively)-T120 (P=0.043 and P=0.044, respectively). PLR was disappeared from T10 (P=0.034) to T90 (P=0.041). In the second phase, mydriasis was only observed in 2/8 eyes. This study suggested that rocuronium bromide was able to produce mydriasis in pigeons other than bull eye iris.

Totally implantable enzymatic biofuel cell and brain stimulator operating in bird through wireless communication.

Animals digest food to fuel brain neurometabolism via cellular respiration. This study demonstrates the combination of a biofuel cell (BFC) and an animal brain stimulator (ABS) implanted in a pigeon. Glucose oxidation and oxygen reduction in an enzymatic BFC supplied electrical power to the ABS. Power from the BFC reached 0.12 mW in vitro and 0.08 mW in vivo using only the natural glucose and oxygen in the pigeon's body. A power management integrated circuit is used to harvest energy from the in vivo BFC at a rate of 28.4 mJ over 10 min, which is sufficient for intermittent neurostimulation.

Relationship of sociodemographic and anthropometric characteristics, and nutrient and food intakes with osteoarthritis prevalence in elderly subjects with controlled dyslipidaemia: a cross-sectional study.

BACKGROUND AND OBJECTIVES: Several studies have suggested that abnormal levels of serum cholesterol may be a major risk factor for osteoarthritis. However, no studies have been conducted to prevent osteoarthritis under controlled conditions of serum cholesterol. This study aimed to examine the relationship of sociodemographic and anthropometric characteristics, and nutrient and food intakes with osteoarthritis prevalence in Korean elderly subjects with controlled dyslipidaemia. METHODS AND STUDY DESIGN: This study included 314 subjects aged ≥65 years who were diagnosed and treated for dyslipidaemia (data from the Seventh Korea National Health and Nutrition Examination Survey, 2016). Among them, 108 were also diagnosed with osteoarthritis. Sociodemographic, health, and nutritional data were analysed. RESULTS: Osteoarthritis prevalence was higher in females, highereducated subjects, unmarried subjects, non-smokers, and subjects with high body mass index (p<0.05). After adjusting for the multiple variables, the non-osteoarthritis group had significantly higher vitamin C intake (132±11.0 vs 93.1±11.1 mg/day), fish intake (172±30.0 vs 79.0±12.9 g/day), and seaweed intake (93.7±19.3 vs 38.3±13.4 mg/day) than the osteoarthritis group. Furthermore, the lowest vitamin C, fish, seaweed intake group (quartile 1) each had 3.20, 2.76, 9.93 times higher risk of osteoarthritis than the highest vitamin C, fish, seaweed intake group (quartile 4) (p<0.05). CONCLUSIONS: Among Korean elderly subjects with controlled dyslipidaemia, those with osteoarthritis had lower vitamin C, fish, seaweed intakes than those without osteoarthritis. Although our results do not prove that low vitamin C, fish, seaweed intakes cause osteoarthritis, such relationship is worth exploring for a preventive perspective.

The definition and diagnosis of cold hypersensitivity in the hands and feet: Finding from the experts survey.

BACKGROUND: Cold hypersensitivity in the hands and feet (CHHF) is a symptom patients usually feel cold in their hands and feet, but not dealt with a disease in western medicine. However, it is often appealed by patients at a clinic of Korean medicine (KM), considered to be a sort of key diagnostic indicator, and actively treated by physicians. Nevertheless, there is no standardized diagnostic definition for CHHF. Therefore, we surveyed KM experts' opinions to address the clinical definition, diagnostic criteria, and other relevant things on CHHF. METHODS: We developed a survey to assess the definition, diagnosis, causes, and accompanying symptoms on CHHF. 31 experts who work at specialized university hospitals affiliated with KM hospitals consented to participation. Experts responded to survey questions by selecting multiple-choice answers or stating their opinions. RESULTS: Vast majority of experts (83.8%) agreed with our definition on CHHF ("a feeling of cold as a symptom; that one's hands or feet become colder than those of average people in temperatures that are not normally perceived as cold"). 77.4% of experts considered subjective symptoms on CHHF were more important than medical instrument results. Constitution or genetic factors (87.1%) and stress (64.5%) were the most common causes reported for CHHF. CONCLUSIONS: This study offers an expert consensus regarding the themes, opinions, and experiences of practitioners with CHHF. Our results underscore the need for standardized definitions and diagnostic criteria for CHHF.

Direct effect of dexmedetomidine on rat isolated aorta involves endothelial nitric oxide synthesis and activation of the lipoxygenase pathway.

1. The aims of the present in vitro study were to examine the roles of pathways associated with arachidonic acid metabolism in dexmedetomidine-induced contraction and to determine which endothelium-derived vasodilators are involved in the endothelium-dependent attenuation of vasoconstriction elicited by dexmedetomidine. 2. Dexmedetomidine (10(-9)-10(-6) mol/L) concentration-response curves were constructed in: (i) aortic rings with no drug pretreatment; (ii) endothelium-denuded aortic rings pretreated with either 2 x 10(-5) mol/L quinacrine dihydrochloride, 10(-5) mol/L nordihydroguaiaretic acid (NDGA), 3 x 10(-5) mol/L indomethacin or 10(-5) mol/L fluconazole; and (iii) endothelium-intact aortic rings pretreated with either 5 x 10(-5) mol/L N(G)-nitro-l-arginine methyl ester (l-NAME), 10(-5) mol/L fluconazole, 10(-5) mol/L indomethacin, 10(-5) mol/L glibenclamide, 5 x 10(-3) mol/L tetraethylammonium or 5 x 10(-5) mol/L l-NAME plus rauwolscine (10(-5), 10(-6) mol/L). The production of nitric oxide (NO) metabolites was determined in human umbilical vein endothelial cells treated with dexmedetomidine. 3. Quinacrine dihydrochloride, NDGA and indomethacin attenuated the dexmedetomidine-induced contraction of endothelium-denuded rings. Dexmedetomidine (10(-7)-10(-6) mol/L)-induced contractions of endothelium-denuded rings were enhanced compared with those of endothelium-intact rings, as were dexmedetomidine-induced contractions of endothelium-intact rings pretreated with l-NAME or tetraethylammonium. Rauwolscine attenuated dexmedetomidine-induced contractions in endothelium-intact rings pretreated with l-NAME. Dexmedetomidine (10(-6) mol/L) was found to activate NO production. 4. Taken together, the results indicate that dexmedetomidine-induced contraction of aortic rings involves activation of the lipoxygenase and cyclo-oxygenase pathways and is attenuated by increased NO production following stimulation of endothelial alpha(2)-adrenoceptors by dexmedetomidine.