Extreme plasticity of reproductive state in a female rodent.

Successful sexual reproduction relies on the coordination of multiple biological systems, yet traditional concepts of biological sex often ignore the natural plasticity in morphology and physiology underlying sex. Most female mammals develop a patent (i.e., opened) vaginal entrance (introitus) prenatally or postnatally before or during puberty, usually under the influence of estrogens, and remain patent for the remainder of their lifespan1. An exception is the southern African giant pouched rat (Cricetomys ansorgei), whose vaginal introitus remains sealed well into adulthood2. Here, we explore this phenomenon and report that the reproductive organs and the vaginal introitus can undergo astounding and reversible transformation. Non-patency is characterized by reduced uterine size and the presence of a sealed vaginal introitus. Furthermore, the female urine metabolome shows that patent and non-patent females profoundly differ in their urine content, a reflection of differences in physiology and metabolism. Surprisingly, patency state did not predict fecal estradiol or progesterone metabolite concentrations. Exploring the plasticity that exists in reproductive anatomy and physiology can uncover that traits long considered 'fixed' in adulthood can become plastic under specific evolutionary pressures. Moreover, the barriers to reproduction that such plasticity creates present unique challenges to maximizing reproductive potential.

Serial evaluation of thoracic radiographs and acute phase proteins in dogs with pneumonia.

BACKGROUND: Acute phase proteins (APP) may guide treatment of pneumonia in dogs but correlations with radiographic abnormalities are poorly characterized. OBJECTIVES: Develop a thoracic radiographic severity scoring system (TRSS), assess correlation of radiographic changes with APP concentrations, and compare time to APP and radiograph normalization with duration of antimicrobials treatment. ANIMALS: Sixteen client-owned dogs, 12 with aspiration pneumonia, and 4 with community-acquired pneumonia. METHODS: Concentrations of C-reactive protein (CRP), serum amyloid A (SAA), and haptoglobin were measured on days 1, 3, 7, 14, 28, and 60 and orthogonal 2-view thoracic radiographs were obtained on days 1, 7, 14, 28, and 60. Treatment was clinician-guided and blinded to APP concentrations. Radiographic severity scores were assigned by blinded, randomized retrospective review by 2 board-certified radiologists with arbitration by a third radiologist. RESULTS: Median (interquartile range [IQR]) time to normalization of CRP (7 days [7-14]) and SAA concentrations (7 days [7-14]) were shorter than antimicrobial treatment duration (17.5 days [14.5-33.5]; P = .001 and .002, respectively) and TRSS normalization (14 days [8.8-52], P = .02 and .02, respectively). The CRP and SAA concentrations were positively correlated with TRSS (CRP rs , 0.643; SAA rs , 0.634; both P < .0001). Both CRP and SAA identified normal thoracic radiographs area under the curve (AUC) 0.873 and 0.817, respectively, both P < .0001. Interobserver agreement for TRSS assignment was moderate (κ, .499; P < .0001). CONCLUSION AND CLINICAL IMPORTANCE: Concentrations of CRP and SAA normalized before radiographic resolution and before clinicians discontinued antimicrobial treatment. The CRP and SAA concentrations may guide duration of antimicrobial treatment for dogs with pneumonia.

Selected advanced imaging techniques were unable to quantify in vivo parasitic burden in heartworm-infested dogs.

This prospective exploratory study aimed to determine whether certain noninvasive advanced imaging techniques could estimate parasitic burden in heartworm-infested dogs; a noninvasive method is needed for ethical considerations and permitting longitudinal drug studies. Three cardiac-gated and respiratory-gated 3T MRI techniques and CT pulmonary angiography (CTPA) were performed in three healthy beagles to optimize imaging techniques. Once the imaging techniques were established, a pilot study was performed to determine which one of the MRI techniques would be used in an observer comparison study. Ultimately, spoiled gradient recalled (SPGR)-cine-MRI and CTPA were performed in four and five heartworm-infested dogs, respectively. Heartworms were detected in the pulmonary arteries in all dogs during SPGR-cine-MRI and in no dog during CTPA. However, counting the number of worms was unsuccessful. In conclusion, CTPA and SPGR-cine-MRI were unable to replace necropsy for quantifying parasitic burden in heartworm-infested dogs.

MRI-based relationships between spine pathology, intervertebral disc degeneration, and muscle fatty infiltration in chondrodystrophic and non-chondrodystrophic dogs.

BACKGROUND CONTEXT: Human studies have revealed a link between muscle degeneration and low back pain, although the cause and effect of this relationship is not clear. Dogs provide a naturally developing model of intervertebral disc (IVD)-related low back pain that may provide insight into relationships between IVD and muscle degeneration. PURPOSE: This study aimed to quantify, via magnetic resonance imaging (MRI), the magnitude and location of fatty infiltration in spine muscles of chondrodystrophic (CD) and non-chondrodystrophic (NCD) dogs suffering from both intervertebral disc herniation (IVDH) and non-disc-related spinal disorders, and relate this to intervertebral disc degeneration (IVDD). STUDY DESIGN: This study used retrospective MRI-based analysis of IVDD and muscle fatty infiltration in CD and NCD dogs. METHODS: A portion of this study was funded ($1,000) by the Pet Trust Fund, Ontario Veterinary College. Magnetic resonance imaging from 180 dogs were separated into four groups: (1) CD with IVDH; (2) CD with non-IVDH spinal pathology; (3) NCD with IVDH; (4) NCD with non-IVDH spinal pathology. For each dog at intervertebral levels T12-T13 to L6-L7, IVDD was subjectively graded and muscle-fat indices (MFIndices) were quantified for multifidus, erector spinae, and psoas muscle groups. RESULTS: Intervertebral disc degeneration grade was higher (p<.0001) for CD compared with NCD dogs, and for dogs diagnosed with IVDH compared with dogs with non-IVDH pathology. Muscle-fat indices of multifidus and psoas were higher (p<.01), indicating greater fatty infiltration, for NCD compared with CD dogs, and for dogs with non-IVDH pathology compared with dogs with IVDH. Erector spinae demonstrated higher (p<.0001) MFIndices compared with multifidus and psoas; however, this level of fatty infiltration was not dependent upon breed or pathology. CONCLUSIONS: Dog groups with higher average IVDD grades demonstrated less fatty infiltration within their multifidus and psoas muscles, compared with groups with lower IVDD grades. This finding was consistent across both CD and NCD breeds as well as across dogs presenting with IVDH and those presenting with a non-IVDH spinal pathology. Thus, the presence or severity of IVDD is not uniquely related to fatty infiltration in these muscles, but rather the presence, or possibly severity or chronicity, of general spine pathology is likely a better predictor of fatty infiltration.

Imaging diagnosis--temporomandibular joint dysplasia in a Basset Hound.

A 5-month-old intact male Basset Hound presented for evaluation of pain and crepitation during manipulation of the temporomandibular joint, worse on the right side. A computed tomography (CT) scan of the head was performed. The CT images demonstrated the osseous features of temporomandibular joint dysplasia and facilitated a 3D reconstruction, which allowed better visualization of the dysplastic features. The patient responded to conservative management with a tape muzzle with no recurrence reported by the owner 6 months after presentation.

The Ontario Veterinary College Hip Certification Program -- assessing inter- and intra-observer repeatability and comparison of findings to those of the Orthopedic Foundation for Animals.

In Canada, the Ontario Veterinary College (OVC) has offered radiographic screening for hip dysplasia for many years, but there are other options for this service including the Orthopedic Foundation for Animals (OFA). There are some differences between the OFA and the OVC methods, and this study compares the OVC and OFA hip certification results in 37 dogs. There was good agreement between the two programs but in some instances there was a difference in the pass/fail status of a dog. Neither the OFA nor the OVC was more likely to fail or pass a given dog. The repeatability of the OVC results was assessed by both inter- and intra-observer comparisons in 100 dogs. There was at least 86% agreement among and within radiologists, but in 5 cases the disagreement resulted in a difference in the pass/fail status of the dog. These results illustrate the inherent variation in radiographic hip evaluation and highlight the importance of consensus grading practices to improve the accuracy of hip evaluation.

Programme de certification des hanches de l'Ontario Veterinary College ­ Évaluation de la reproductibilité inter- et intra-observateur et comparaison des résultats à ceux de l'Orthopedic Foundation for Animals. Au Canada, l'Ontario Veterinary College (OVC) offre le dépistage radiographique de la dysplasie de la hanche depuis de nombreuses années, mais il y a d'autres options pour ce service, incluant l'Orthopedic Foundation for Animals (OFA). Il y a certaines différences entre les méthodes de l'OFA et de l'OVC et cette étude compare les résultats de certification de la hanche de l'OVC et de l'OFA chez 37 chiens. Il y avait une bonne concordance entre les deux programmes, mais dans certains cas, il y avait une différence au niveau du statut d'échec-réussite d'un chien. Ni l'OFA ni l'OVC ne présentait une probabilité accrue de donner un résultat d'échec ou de réussite à un chien particulier. La reproductibilité des résultats de l'OVC a été évaluée par des comparaisons inter- et intra-observateur chez 100 chiens. Il y avait au moins 86 % de concordance entre et parmi les radiologistes, mais dans 5 cas, la discordance s'est traduite par une différence du statut de réussite et d'échec chez le chien. Les résultats illustrent la variation inhérente à l'évaluation radiographique de la hanche et souligne l'importance de pratiques de classification par consensus afin d'améliorer l'exactitude de l'évaluation de la hanche.(Traduit par Isabelle Vallières).