Digital Knowledge Collection:

Radiographic screening of indigenous South African rodent incisor teeth for the presence of elodontomas

Wed, 01 Jan 2025 00:00:00 GMT

Title: Radiographic screening of indigenous South African rodent incisor teeth for the presence of elodontomas Authors: NORVAL, QUINTIN; Tordiffe, Adrian; Steenkamp, Gerhard Abstract: Elodontomas, benign growths affecting the continuously growing incisor teeth of rodents, are a significant concern in captive populations, often causing severe respiratory distress due to nasal obstruction. This study aimed to investigate the presence of elodontomas in South African rodents to propose a classification system for the anatomical location of maxillary incisor apices, which may influence susceptibility to respiratory issues. Radiographic screening of 376 dry skulls from 63 rodent species housed in the Ditsong National Museum of Natural History's small mammal archives, revealed no evidence of elodontomas. The absence of elodontomas in wild rodents supports the hypothesis that captivity-related factors such as diet, housing, and trauma may contribute to elodontoma development. Rodent species were classified based on the maxillary incisor apex location: Class I (rostral to the first cheek tooth, 80.95%), Class II (between the cheek teeth, 14.29%), and Class III (caudal to the last cheek tooth, 4.76%). The study highlights the importance of additional in-depth research into the incidence of elodontomas, particularly concerning the difference between wild and captive populations. A classification system is proposed that provides a framework for assessing anatomical susceptibility to respiratory distress linked to dental abnormalities, which could offer insights for improving rodent welfare in captive settings.

Radiological landmarks as an aid in the interpretation of rodent skull extra‐oral projections

Wed, 01 Jan 2025 00:00:00 GMT

Title: Radiological landmarks as an aid in the interpretation of rodent skull extra‐oral projections Authors: NORVAL, QUINTIN; Tordiffe, Adrian; Steenkamp, Gerhard Abstract: Knowledge of the radiographic anatomy of rodent skulls is essential for accurately interpreting extra-oral radiographs, a non-invasive diagnostic tool commonly used in veterinary practice. Due to the complexity of the skull and the potential for distortion in two-dimensional views, a systematic evaluation of anatomical structures is necessary. This study identifies the most clinically relevant anatomical landmarks on standard extra-oral radiographic views of the skull and mandible in various rodent species, including a cane rat, two woodchucks, and seven common mole rats. Specimens were evaluated with bone and soft tissue intact, as well as dried skulls, to identify key anatomical features. The findings highlight distinct species-specific variations despite general similarities in skull structure. These landmarks were catalogued to aid veterinary professionals in interpreting rodent radiographs. Improved recognition of these structures enhances diagnostic accuracy, enabling better assessment of normal anatomy and potential pathological conditions in rodent patients.

Are very high rates of exogenous carbohydrate ingestion (>90 g/hr) su cient or indeed necessary to run a sub-2hr marathon? An analysis of the model predictions of Lukasiewicz and colleagues

Wed, 01 Jan 2025 00:00:00 GMT

Title: Are very high rates of exogenous carbohydrate ingestion (>90 g/hr) su cient or indeed necessary to run a sub-2hr marathon? An analysis of the model predictions of Lukasiewicz and colleagues Authors: Noakes, Timothy David; Prins, Philip J.

Carbohydrate ingestion eliminates hypoglycemia and improves endurance exercise performance in triathletes adapted to very low- and high-carbohydrate isocaloric diets

Wed, 01 Jan 2025 00:00:00 GMT

Title: Carbohydrate ingestion eliminates hypoglycemia and improves endurance exercise performance in triathletes adapted to very low- and high-carbohydrate isocaloric diets Authors: Prins, Philip; Noakes, Timothy David; Buga, Alex; Gerhart, Hayden D.; Cobb, Brandon M.; D'Agostino, Dominic; Volek, Jeff; Buxton, Jeffrey D.; Heckman, Kara; Plank, Emma; DiStefano, Samuel; Flaming, Isaak; Kirsch, Lauren; Lagerquist, Britta; Larson, Emily; Koutnik, Andrew Abstract: ry-low-carbohydrate diets (LCHF; <50 g/day) have been debated for their potential to lower pre-exercise muscle and liver glycogen stores and metabolic efficiency, risking premature fatigue. It is also hypothesized that carbohydrate ingestion during prolonged exercise delays fatigue by increasing carbohydrate oxidation, thereby sparing muscle glycogen. Leveraging a randomized crossover design, we evaluated performance during strenuous time-to-exhaustion (70% V_O2max) tests in trained triathletes following 6-wk high-carbohydrate (HCLF, 380 g/day) or very-low-carbohydrate (LCHF, 40 g/day) diets to determine 1) if adoption of the LCHF diet impairs time-to-exhaustion performance, 2) whether carbohydrate ingestion (10 g/h) 6–12 lower than current CHO fueling recommendations during low glycogen availability (>15-h pre-exercise overnight fast and/or LCHF diet) improves time to exhaustion by preventing exercise-induced hypoglycemia (EIH; <3.9 mmol/L; <70 mg/ dL), and 3) the“keto-adaptation” time course through continuous substrate monitoring while caloric intake, physical activity, and fat-free mass are maintained. Time-to-exhaustion performance was similar across both dietary interventions. Minimal carbohydrate supplementation prevented EIH and significantly increased time to exhaustion equivalently in LCHF and HCLF interventions (22%). The LCHF diet significantly lowered 24-h glucose concentrations, which normalized after 4 wk, at the same timepoint peak blood ketone (R-b-hydroxybutyrate) concentrations normalized. These findings 1) demonstrate that an LCHF diet sustains strenuous endurance performance, 2) establish that minimal carbohydrate supplementation was sufficient to enhance exercise performance on LCHF and HCLF diets by mitigating EIH, and 3) indicate that a minimum 4-wk adaptation period to an LCHF diet is required to ensure normalization of metabolic homeostasis, glycemic control, and exercise performance. NEW & NOTEWORTHY This study examines the belief that very-low-carbohydrate diets (LCHF) impair prolonged exercise performance during strenuous exercise by comparing it with high-carbohydrate diets in competitive triathletes. After 6-wk diet adaptation, time-to-exhaustion (TTE) performance was similar across both diets. Minimal carbohydrate supplementation (10 g/h) during exercise eliminated exercise-induced hypoglycemia and improved TTE by 22% on both diets. These findings suggest that LCHF diets do not impair exercise performance and require a 4-wk adaptation period for metabolic homeostasis.