Students Satisfaction with the Use of PlayDoh® as a Tool to Actively Learn 3D Veterinary Anatomy More Accurately.

Understanding veterinary anatomy is an essential skill for the study of veterinary medicine as well as for diagnostic imaging and therapy. Dissection facilities are increasingly limited in some schools and its alternatives have often focussed on using two-dimensional images. However, the study of veterinary anatomy is mainly concerned with identifying structures and spatial relationships between them within a 3D space, and the use of 2D teaching approaches does not provide accurate information. We tested whether PlayDoh® student-built models could be an inexpensive potential tool beneficial to veterinary students learning anatomy in three distinct scenarios: (1) during a lecture, introducing a new concept; (2) during a flipped classroom approach where a video-podcast lecture was to be watched by the students prior to the lecture and (3) as a revision session where students brought their own questions and created, under supervision, their own models to respond to them. PlayDoh® sessions benefitted 172 first-year Veterinary Medicine and Animal Science students. The most accurate visualisation of anatomical structures in 3D was the principal benefit mentioned by the learners (35%). In addition, the learners noted that the technique would help with 'retention' (18%). According to the students' preferences, it was possible to create four groups: A, B, C and D. Group A encompassed the methodologies most liked by students and consisted of lectures, dissection and demonstrations. Group B included demonstrations and 3D modelling using PlayDoh®. Group C consisted of 3D modelling using PlayDoh®, books and online and, finally, group D included the methodologies least preferred by students, i.e. online and PBL. Our findings suggest that using 3D PlayDoh® modelling has potential as a method to enhance the learning of veterinary anatomy and may be most valuable to those students learning more complex subject areas that require a 3D teaching approach in practice. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-023-01892-y.

The Effects of Annual Maintenance on Peri-implant Health in Patients Rehabilitated with Overdentures: A Retrospective Cohort Study.

PURPOSE: The aim of this retrospective cohort study was to assess the effects of annual maintenance over a 7-year period on the peri-implant health of patients rehabilitated with overdentures using clinical and radiographic parameters. MATERIALS AND METHODS: In order to be considered for inclusion in the study, patients had to have been rehabilitated with overdentures that had at least two implants placed in the mandible and four implants in the maxilla. Patients were divided into two groups: group 1 comprised individuals who had undergone annual maintenance over the previous 7 years, and group 2 comprised those who had not attended any dental appointment over the previous 7 years. All patients were submitted to clinical peri-implant examinations and radiographic assessments. RESULTS: Sixty-six patients received 396 implants of the external hexagon type, 132 in the mandible and 264 in the maxilla. Group 1 (44 patients with 264 implants) had a mean probing depth of 2.72 mm, while group 2 (22 patients with 132 implants) had a mean probing depth of 3.10 mm. It can be concluded that the mean of the variable probing depth is influenced by the presence of bleeding (P = .0005) and the implementation of maintenance (P = .0188), whereas plaque and local variables were not otherwise significant (P = .0605 and .0796, respectively). CONCLUSION: In this study, it was possible to observe better clinical conditions in individuals who had attended annual appointments for maintenance purposes.

Stereological and allometric studies on neurons and axo-dendritic synapses in the superior cervical ganglia of rats, capybaras and horses.

The superior cervical ganglion (SCG) in mammals varies in structure according to developmental age, body size, gender, lateral asymmetry, the size and nuclear content of neurons and the complexity and synaptic coverage of their dendritic trees. In small and medium-sized mammals, neuron number and size increase from birth to adulthood and, in phylogenetic studies, vary with body size. However, recent studies on larger animals suggest that body weight does not, in general, accurately predict neuron number. We have applied design-based stereological tools at the light-microscopic level to assess the volumetric composition of ganglia and to estimate the numbers and sizes of neurons in SCGs from rats, capybaras and horses. Using transmission electron microscopy, we have obtained design-based estimates of the surface coverage of dendrites by postsynaptic apposition zones and model-based estimates of the numbers and sizes of synaptophysin-labelled axo-dendritic synaptic disks. Linear regression analysis of log-transformed data has been undertaken in order to establish the nature of the relationships between numbers and SCG volume (V(scg)). For SCGs (five per species), the allometric relationship for neuron number (N) is N=35,067xV (scg) (0.781) and that for synapses is N=20,095,000xV (scg) (1.328) , the former being a good predictor and the latter a poor predictor of synapse number. Our findings thus reveal the nature of SCG growth in terms of its main ingredients (neurons, neuropil, blood vessels) and show that larger mammals have SCG neurons exhibiting more complex arborizations and greater numbers of axo-dendritic synapses.

Atrophy and neuron loss: effects of a protein-deficient diet on sympathetic neurons.

Protein deficiency is one of the biggest public health problems in the world, accounting for about 30-40% of hospital admissions in developing countries. Nutritional deficiencies lead to alterations in the peripheral nervous system and in the digestive system. Most studies have focused on the effects of protein-deficient diets on the enteric neurons, but not on sympathetic ganglia, which supply extrinsic sympathetic input to the digestive system. Hence, in this study, we investigated whether a protein-restricted diet would affect the quantitative structure of rat coeliac ganglion neurons. Five male Wistar rats (undernourished group) were given a pre- and postnatal hypoproteinic diet receiving 5% casein, whereas the nourished group (n = 5) was fed with 20% casein (normoproteinic diet). Blood tests were carried out on the animals, e.g., glucose, leptin, and triglyceride plasma concentrations. The main structural findings in this study were that a protein-deficient diet (5% casein) caused coeliac ganglion (78%) and coeliac ganglion neurons (24%) to atrophy and led to neuron loss (63%). Therefore, the fall in the total number of coeliac ganglion neurons in protein-restricted rats contrasts strongly with no neuron losses previously described for the enteric neurons of animals subjected to similar protein-restriction diets. Discrepancies between our figures and the data for enteric neurons (using very similar protein-restriction protocols) may be attributable to the counting method used. In light of this, further systematic investigations comparing 2-D and 3-D quantitative methods are warranted to provide even more advanced data on the effects that a protein-deficient diet may exert on sympathetic neurons. (c) 2009 Wiley-Liss, Inc.

The developing left superior cervical ganglion of Pacas (Agouti paca).

In this study the main question investigated was the number and size of both binucleate and mononucleate superior cervical ganglion (SCG) neurons and, whether post-natal development would affect these parameters. Twenty left SCGs from 20 male pacas were used. Four different ages were investigated, that is newborn (4 days), young (45 days), adult (2 years), and aged animals (7 years). By using design-based stereological methods, that is the Cavalieri principle and a physical disector combined with serial sectioning, the total volume of ganglion and total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal (somal) volume of mononucleate and binucleate neurons was estimated using the vertical nucleator. The main findings of this study were a 154% increase in the SCG volume, a 95% increase in the total number of mononucleate SCG neurons and a 50% increase in the total volume of SCG neurons. In conclusion, apart from neuron number, different adaptive mechanisms may coexist in the autonomic nervous system to guarantee a functional homeostasis during ageing, which is not always associated with neuron losses.

The developing and restructuring superior cervical ganglion of guinea pigs (Cavia porcellus var. albina).

Post-natal development comprises both maturation (from newborn to adult) and ageing (from adult to senility) and, during this phase, several adaptive mechanisms occur in sympathetic ganglia, albeit they are not fully understood. Therefore, the present study aimed at detecting whether post-natal development would exert any effect on the size and number of a guinea pig's superior cervical ganglion (SCG) neurons. Twenty right SCGs from male subjects were used at four ages, i.e. newborn (7 days), young (30 days), adult (7 months) and old animals (50 months). Using design-based stereological methods the volume of ganglion and the total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal volume of mononucleate and binucleate neurons was estimated using the vertical nucleator. The main findings of this study were a combination of post-natal-dependent increases and decreases in some variables: (i) 27% increase in ganglion volume, (ii) 24% and 43% decreases in the total number of mono and binucleate neurons, respectively, and (iii) 27.5% and 40% decreases in the mean perikaryal volume of mono and binucleate neurons, respectively. Despite the fall in neuron numbers found here, post-natal development is not only associated with neuron loss, but also embraces other structural adaptive mechanisms, which are discussed in this paper.

Low-intensity treadmill exercise-related changes in the rat stellate ganglion neurons.

Stellate ganglion (SG) represents the main sympathetic input to the heart. This study aimed at investigating physical exercise-related changes in the quantitative aspects of SG neurons in treadmill-exercised Wistar rats. By applying state-of-the-art design-based stereology, the SG volume, total number of SG neurons, mean perikaryal volume of SG neurons, and the total volume of neurons in the whole SG have been examined. Arterial pressure and heart rate were also measured at the end of the exercise period. The present study showed that a low-intensity exercise training program caused a 12% decrease in the heart rate of trained rats. In contrast, there were no effects on systolic pressure, diastolic pressure, or mean arterial pressure. As to quantitative changes related to physical exercise, the main findings were a 21% increase in the fractional volume occupied by neurons in the SG, and an 83% increase in the mean perikaryal volume of SG neurons in treadmill-trained rats, which shows a remarkable neuron hypertrophy. It seems reasonable to infer that neuron hypertrophy may have been the result of a functional overload imposed on the SG neurons by initial posttraining sympathetic activation. From the novel stereological data we provide, further investigations are needed to shed light on the mechanistic aspect of neuron hypertrophy: what role does neuron hypertrophy play? Could neuron hypertrophy be assigned to the functional overload induced by physical exercise?