The choroid, a multifunctional tissue, has been the focus of research interest for many scientists. Its morphology and morphometry facilitate an understanding of pathological processes within both the choroid and retina. This study aimed to determine the choroidal layer thicknesses in healthy, mixed-breed mesocephalic dogs, both male (M) and female (F), using spectral domain optical coherence tomography (SD-OCT) with radial, cross-sectional, and linear scans. The dogs were divided into two groups based on age: middle-aged (MA) and senior (SN). Thicknesses of choroidal layers, namely RPE–Bruch’s membrane–choriocapillaris complex (RPE-BmCc) with tapetum lucidum in the tapetal fundus, the medium-sized vessel layer (MSVL), and the large vessel layer with lamina suprachoroidea (LVLS), as well as whole choroidal thickness (WCT), were measured manually using the caliper function integrated into the OCT software. Measurement was performed dorsally and ventrally at a distance of 5000–6000 μm temporally and nasally at a distance of 4000–7000 μm to the optic disc on enhanced depth scans. The measurements were conducted temporally and nasally in both the tapetal (temporal tapetal: TempT, nasal tapetal: NasT) and nontapetal (temporal nontapetal: TempNT, nasal nontapetal: NasNT) fundus. The ratio of the MSVL thickness to the LVLS thickness for each region was calculated. In all examined dogs, the RPE-BmCc in the dorsal (D) region and MSVL in the Tt region were significantly thicker than those in the other regions. The MSVL was thinner in the ventral (V) region than in the D, TempT, TempNT and NasT regions. The MSVL was significantly thinner in the NasNT region than in the D region. LVLS thickness and WCT were significantly greater in the D and TempT regions than those in the other regions and significantly lesser in the V region than those in the other regions. The MSVL-to-LVLS thickness ratio did not differ between the age groups. Our results reveal that the choroidal thickness profile does not depend on age. Our findings can be used to document the emergence and development of various choroidal diseases in dogs in the future.

Background: This longitudinal study examined the early effects of type 1 diabetes on bone mechanical properties and metabolic markers in mature rats, focusing on the natural progression of diabetes-induced changes without external treatments. Methods: Forty-eight 8-month-old male Wistar rats were divided into two groups, with one group receiving a single dose of streptozotocin (STZ, 60 mg/kg). Assessments were performed 2, 4, and 8 weeks post-administration, including serum biochemical analyses, bone marker assessments, and mechanical bone tests. The data were analyzed using two-way ANOVA to evaluate the impact of time and treatment. Results: At 2 weeks, diabetic rats showed increased fasting blood glucose (p < 0.001), decreased insulin levels (p = 0.03), and changes in HOMA markers (p < 0.001), liver enzymes (p < 0.001), inflammatory markers (p < 0.001), and bone metabolism markers (osteocalcin (p < 0.001), OPG (p = 0.006), RANKL (p < 0.001), and OPG/RANKL ratio (p < 0.001)), with initial alterations in bone geometry. By week 4, decreased body weight in the diabetic group (p < 0.001) led to further changes in bone geometry and initial differences in mechanical properties. At 8 weeks, significant declines in body (p < 0.001) and bone (p < 0.001) weights were observed, along with further deterioration in bone geometry and mechanical properties. Conclusions: The study highlights the significant impact of STZ-induced diabetes on bone health as early as two weeks post-STZ administration, with marked temporal changes in biochemical markers and mechanical properties.

Evaluating a PEGylated human serum albumin (HSA) nanoparticle system for brain-derived neurotrophic factor and neurotrophin-3 co-delivery.

Introduction: Chlamydia felis is the main chlamydial pathogen of cats and is associated with conjunctivitis and respiratory disease. This study aimed to estimate the prevalence of Chlamydiaceae and Chlamydia felis , to explore risk factors and predictors (age, sex, breed, origin and ocular signs) for infection using logistic regression, and to appraise genetic diversity via omp A sequencing and phylogenetic analysis. Material and Methods: Conjunctival swabs from 156 cats were examined using real-time PCR assays for Chlamydiaceae and C. felis . Logistic regression and Kaplan–Meier analysis evaluated risk factors, and partial omp A sequences were phylogenetically analysed. Results: Chlamydiaceae DNA was detected in 7.7% (12/156) of cats and was identified as C. felis . Infections were mostly unilateral. Threshold cycle values varied widely, suggesting heterogeneous bacterial loads. Younger age was a significant risk factor, and the probability of infection decreased steadily with age. Ocular signs strongly predicted infection. British Shorthair/Longhair cats had more than threefold higher odds of infection than European Shorthair cats. Phylogenetic analysis of omp A showed very high genome conservation (99.7–100%), which was consistent with global data. Conclusion: This first molecular study of C. felis in Poland in ten years demonstrates that infection mainly affects young, purebred cats with apparent conjunctivitis. The genetic stability of omp A supports the concept of a globally homogeneous C. felis population.