Impact of fecal sample preservation and handling techniques on the canine fecal microbiota profile.

Canine fecal microbiota profiling provides insight into host health and disease. Standardization of methods for fecal sample storage for microbiomics is currently inconclusive, however. This study investigated the effects of homogenization, the preservative RNAlater, room temperature exposure duration, and short-term storage in the fridge prior to freezing on the canine fecal microbiota profile. Within 15 minutes after voiding, samples were left non-homogenized or homogenized and aliquoted, then kept at room temperature (20-22°C) for 0.5, 4, 8, or 24 hours. Homogenized aliquots then had RNAlater added or not. Following room temperature exposure, all aliquots were stored in the fridge (4°C) for 24 hours prior to storing in the freezer (-20°C), or stored directly in the freezer. DNA extraction, PCR amplification, then sequencing were completed on all samples. Alpha diversity (diversity, evenness, and richness), and beta diversity (community membership and structure), and relative abundances of bacterial genera were compared between treatments. Homogenization and RNAlater minimized changes in the microbial communities over time, although minor changes in relative abundances occurred. Non-homogenized samples had more inter-sample variability and greater changes in beta diversity than homogenized samples. Storage of canine fecal samples in the fridge for 24 h prior to storage in the freezer had little effect on the fecal microbiota profile. Our findings suggest that if immediate analysis of fecal samples is not possible, samples should at least be homogenized to preserve the existing microbiota profile.

The effects of ambient temperature exposure on feline fecal metabolome.

Introduction: The fecal metabolome provides insight into overall gastrointestinal and microbial health. Methods for fecal sample storage in metabolomics research vary, however, making comparisons within current literature difficult. This study investigated the effect of ambient temperature exposure on microbial-derived metabolites of feline fecal samples. Methods: Fecal samples were collected from 11 healthy cats from a local boarding facility. Samples were manually homogenized and aliquoted. The first aliquot was frozen at -80°C within 1 hour of defecation, and remaining samples were exposed to ambient temperature for 2, 4, 6, 8, 12, and 24 h prior to freezing at -80°C. Fecal metabolites were quantified using 1H NMR spectroscopy. Fifty metabolites were grouped into six categories (27 amino acids, 8 fatty acids, 5 sugars, 3 alcohols, 2 nitrogenous bases, 5 miscellaneous). Results: Concentrations of 20 out of 50 metabolites significantly differed due to ambient temperature exposure (7 amino acids, 6 fatty acids, 2 alcohols, 1 nitrogenous base, 4 miscellaneous). The earliest detected changes occurred 6 h post-defecation for cadaverine and fumaric acid. Discussion: This study shows ambient temperature exposure alters the composition of the feline fecal metabolome, but short-term (up to 4 h) exposure prior to storage in the freezer seems to be acceptable.

Breed predilections and prognosis for subungual squamous cell carcinoma in dogs.

Objective: To better document the prevalence, breed predilections, and clinical behavior of subungual squamous cell carcinomas in dogs. Procedure: Retrospective analysis of records from 278 812 canine biopsy submissions including 1518 subungual squamous cell carcinomas from dogs in Canada between the years 2003 and 2021. Results: In agreement with previous studies, giant schnauzers [odds ratio (OR): 56.7], standard schnauzers (OR: 20.3), Gordon setters (OR: 18.3), black standard poodles (OR: 11.1), Kerry blue terriers (OR: 9.4), Rottweilers (OR: 7.0), and several other breeds of large black dogs had a strong predilection for development of subungual squamous cell carcinomas. In giant schnauzers and standard poodles specifically, the risk of developing additional tumors on additional digits was 56%. There were no local postoperative recurrences, and the risk of detecting metastatic disease within 5 y after initial diagnosis was very low at 4%. Conclusion: Moderately large black, or black and tan, dogs have a marked increase in the prevalence of subungual squamous cell carcinomas. At least in giant schnauzers and black standard poodles, the risk of developing additional similar tumors on additional digits is high, but the metastatic risk is very low. Clinical relevance: Veterinarians receiving a histologic diagnosis of subungual squamous cell carcinoma in a large black (or predominantly black) dog should advise the owners of a substantial risk that the dog will develop similar tumors on other digits in 2 or 3 y following initial diagnosis, but that the risk of local recurrence or metastatic spread is extremely low.

Objectif: Mieux documenter la prévalence, les préférences de race et le comportement clinique des carcinomes épidermoïdes sous-unguéaux chez les chiens. Procédure: Analyse rétrospective des dossiers de 278 812 soumissions de biopsies canines, y compris 1518 carcinomes épidermoïdes sous-unguéaux de chiens au Canada entre 2003 et 2021. Résultats: En accord avec les études précédentes, les schnauzers géants [rapport de cotes (OR): 56,7], les schnauzers standards (OR: 20,3), les setters Gordon (OR: 18,3), les caniches standards noirs (OR: 11,1), les Kerry blue terriers (OR: 9,4), Rottweilers (OR: 7,0) et plusieurs autres races de grands chiens noirs avaient une forte prédilection pour le développement de carcinomes épidermoïdes sous-unguéaux. Chez les schnauzers géants et les caniches standards en particulier, le risque de développer des tumeurs supplémentaires sur des doigts additionnels était de 56 %. Il n'y a pas eu de récidive postopératoire locale et le risque de détecter une maladie métastatique dans les 5 ans suivant le diagnostic initial était très faible à 4 %. Conclusion: Les chiens noirs ou noirs et brun-roux de taille moyenne présentent une augmentation marquée de la prévalence des carcinomes épidermoïdes sous-unguéaux. Au moins chez les schnauzers géants et les caniches standards noirs, le risque de développer des tumeurs similaires supplémentaires sur des doigts additionnels est élevé, mais le risque métastatique est très faible. Pertinence clinique: Les vétérinaires qui reçoivent un diagnostic histologique de carcinome épidermoïde sous-unguéal chez un gros chien noir (ou à prédominance noire) doivent informer les propriétaires d'un risque substantiel que le chien développe des tumeurs similaires sur d'autres doigts dans les 2 ou 3 ans suivant le diagnostic initial, mais que le risque de récidive locale ou de propagation métastatique est extrêmement faible.(Traduit par Dr Serge Messier).

Biochemical signal detection in miniaturized fluidic systems by integrated microresonator.

An optical sensor integrated into a polymer microfluidic chip is proposed as a low cost solution to highly parallel biochemical analysis. The sensor consists of a single high-finesse optical resonator for direct analytes detection. High quality silica microspheres (diameter approximately 300 microm) are easily produced and low-loss whispering gallery modes were excited through evanescent coupling at wavelengths near 1550 nm and 544 nm. The quality factor (Q) and ring down time of these modes is sensitive to minute changes in the microresonator environment thus making it an excellent candidate for a sensor. Instead of the traditional time domain studies, we determine quality factors and ring down times as long as 53.8 +/- 0.6 ns (Q approximately 10(6)) from phase shift measurements using optical sources with sinusoidal intensity modulations of 300 kHz and below.