Session 3: Natural Selection as a Causal Theory

Proceedings of the Pittsburgh Workshop in History and Philosophy of Biology, Center for Philosophy of Science, University of Pittsburgh, March 23-24 2001 Session 3: Natural Selection as a Causal Theor

Prevalence and Risk Factors for Presumptive Ascending/Descending Myelomalacia in Dogs after Thoracolumbar Intervertebral Disk Herniation

Background: Ascending/descending myelomalacia (ADMM) is a severe complication of thoracolumbar intervertebral disk herniation (TL-IVDH) in dogs. Hypothesis/Objectives: To investigate the prevalence and risk factors for ADMM in nonambulatory dogs with surgically treated TL-IVDH. Animals: Six-hundred and fifty-two client-owned dogs evaluated for TL-IVDH that underwent decompressive spinal surgery. Methods: Retrospective medical record review from February 2007 through December 2015. Results: Thirteen dogs developed ADMM, with an overall prevalence of 2.0%. The prevalence of ADMM was 0% in dogs with neurological signs graded 1 or 2 at admission or before magnetic resonance imaging (MRI) or surgical procedures, 0.6% in dogs with neurological signs graded 3, 2.7% in dogs with neurological signs graded 4, and 14.5% in dogs with neu- rological signs graded 5. Age (4.57 were significant risk factors in the univariate analysis for development of ADMM. Conclusions and Clinical Importance: The factors identified in this study may be useful for the prediction of ADMM. Multicenter studies with a higher number of dogs with ADMM are required to confirm these data

Presence of behavioural problems in previously active dogs subjected to convalescence

Behavioural problems have previously been studied in several different species. Stereotypic behaviours, defined as abnormal repetitive behaviours have mostly been studied in captive wild animals while displaced behaviours, defined as misdirected normal behaviours, mostly have been studied in companion animals. Neither stereotypic behaviours nor displaced behaviours are wanted by owners and might also indicate a lower welfare of the individual performing the behaviour. Convalescence is defined as the time while a patient is recovering from an injury or illness. For dogs, convalescence is often related to a period of lowered activity and confined space. The aim of the study was to investigate the presence of behavioural problems in previously active dogs after the onset of convalescence. An online survey was conducted on Swedish dogs used to an active life by competing or training in agility and/or rally obedience. All dogs had experienced convalescence due to a musculoskeletal injury. A total of 75 dogs were used in the results. The results showed that presence of behavioural problems, both stereotypic and displaced behaviours, increased after the onset of convalescence. A majority of the owners did not believe they got the help they wished for from the veterinarian staff regarding how they could activate their dogs during convalescence. The results indicate that previously active dogs might alter their behaviour, by starting to display new behavioural problems, in order to cope with the new situation the convalescence implicates. The altered behaviours could indicate a lowered welfare during convalescence for dogs. Most dogs displaying behavioural problems were convalescent longer than three months, indicating that time might be an important factor. However, further studies are needed in order to verify these first results as well as to clarify if the results differ between dogs of different ages, with different activity levels and of different breeds.Problembeteenden har tidigare studerats hos flera olika arter. Stereotypa beteenden, definierat som onormala repetitiva beteenden, har främst studerats hos vilda djur i fångenskap medan ”felplacerade beteenden”, definierat som missriktade normala beteenden, har främst studerats hos sällskapsdjur. Varken stereotypa beteenden eller felplacerade beteenden önskas av ägarna och kan även vara tecken på en lägre välfärd hos individen som uppvisar beteendet. Konvalescens är den tid som en patient återhämtar sig från skada eller sjukdom. Hos hundar innebär konvalescens ofta en period med lägre aktivitetsnivå och begränsade ytor. Syftet med studien var därför att undersöka om förekomsten av problembeteenden hos tidigare aktiva hundar förändras i och med konvalescens. En online undersökning genomfördes av svenska hundar som var aktiva inom agility och/eller rallylydnad och därmed vara vana vid en aktiv livsstil. Alla hundar hade genomgått en period av konvalescens orsakat av en skada i rörelseapparaten. Totalt 75 hundar inkluderades i resultatet. Resultatet visade att förekomsten av både stereotypa och felplacerade beteenden ökade i och med konvalescensen. Majoriteten av ägarna ansåg att de inte fick den hjälp de önskat från personalen inom djurhälsovården gällande hur de kunde aktivera sin hund under konvalescensen. Resultatet indikerar att tidigare aktiva hundar kan förändra sitt beteende, genom att visa nya problembeteenden, till följd av konvalescens för att hantera den nya situationen. Det förändrade beteendet i form av ökade problembeteenden, kan indikera på en minskad välfärd under konvalescens. De flesta hundar som uppvisade problembeteenden var konvalescenta längre än tre månader, vilket indikerar att tid kan vara en viktig faktor. Det krävs dock vidare studier för att säkerställa resultaten samt för att se om andra faktorer kan påverka resultaten så som hundens ålder, tidigare aktivitetsnivå och ras

Perceived Attractiveness and Personality Attributes: A Gender and Racial Analysis

Subjects rated 12 female body shapes with respect to their physical attractiveness, and the extent to which they would be expected to possess various personality characteristics. The shapes were varied using 3 levels of overall weight and 4 levels of body shapeliness. The sample was modified to control for socioeconomic factors and results are based on 297 undergraduates from Caucasian, African American, and Hispanic racial backgrounds. Loglinear analyses revealed that men and women, regardless of racial background, rated shapely underweight females as most physically attractive, sexy, and ideal for a woman, followed by normal weight figures of similar proportion. African Americans, women in particular, judged the shapely normal weight figures more favorably than the other subjects. Multidimensional scaling and subsequent frequency analyses showed that those figures judged as most attractive, sexy, and ideal were also expected to be fairly emotionally stable, and most successful and interpersonally competitive, but least faithful, kind, and family-oriented. Overweight female shapes, while rated as least physically attractive, sexy, and emotionally stable, were expected to be most family-oriented, kind, and faithful. Shapely normal weight figures were judged to be attractive and sexy, and were assumed to possess a moderate amount of the personality traits in question. The results suggest that Caucasian and Hispanic subjects prefer shapely underweight women, while African Americans, particularly women, find shapely underweight and shapely normal weight women to be physically appealing. African American women also rate shapely normal weight women favorably with respect to personality traits. This perceptual difference may help inoculate them from developing eating disturbances and account for the low prevalence rate of eating disorders in African Americans compared to women of other racial backgrounds. It is suggested that future research identify those beliefs, values or behaviors that seem to inoculate African American women from developing eating disorders. Once identified, mental health professionals may facilitate their development in those women who are likely to have eating problems

Comparison of regional gene expression differences in the brains of the domestic dog and human

Comparison of the expression profiles of 2,721 genes in the cerebellum, cortex and pituitary gland of three American Staffordshire terriers, one beagle and one fox hound revealed regional expression differences in the brain but failed to reveal marked differences among breeds, or even individual dogs. Approximately 85 per cent (42 of 49 orthologue comparisons) of the regional differences in the dog are similar to those that differentiate the analogous human brain regions. A smaller percentage of human differences were replicated in the dog, particularly in the cortex, which may generally be evolving more rapidly than other brain regions in mammals. This study lays the foundation for detailed analysis of the population structure of transcriptional variation as it relates to cognitive and neurological phenotypes in the domestic dog

Evaluation of magnetic resonance imaging guidelines for differentiation between thoracolumbar intervertebral disk extrusions and intervertebral disk protrusions in dogs

Four MRI variables have recently been suggested to be independently associated with a diagnosis of thoracolumbar intervertebral disk extrusion or protrusion. Midline intervertebral disk herniation, and partial intervertebral disk degeneration were associated with intervertebral disk protrusion, while presence of a single intervertebral disk herniation and disk material dispersed beyond the boundaries of the intervertebral disk space were associated with intervertebral disk extrusion. The aim of this retrospective, cross‐sectional study was to determine whether using these MRI variables improves differentiation between thoracolumbar intervertebral disk extrusions and protrusions. Eighty large breed dogs with surgically confirmed thoracolumbar intervertebral disk extrusions or protrusions were included. Randomized MRI studies were presented on two occasions to six blinded observers, which were divided into three experience categories. During the first assessment, observers made a presumptive diagnosis of thoracolumbar intervertebral disk extrusion or protrusion without guidelines. During the second assessment they were asked to make a presumptive diagnosis with the aid of guidelines. Agreement was evaluated by Kappa‐statistics. Diagnostic accuracy significantly improved from 70.8 to 79.6% and interobserver agreement for making a diagnosis of intervertebral disk extrusion or intervertebral disk protrusion improved from fair (κ = 0.27) to moderate (κ = 0.41) after using the proposed guidelines. Diagnostic accuracy was significantly influenced by degree of observer experience. Intraobserver agreement for the assessed variables ranged from fair to excellent and interobserver agreement ranged from fair to moderate. The results of this study suggest that the proposed imaging guidelines can aid in differentiating thoracolumbar intervertebral disk extrusions from protrusions

Erratum: Establishment of a canine spinal cord injury model induced by epidural balloon compression

A model that provides reproducible, submaximal yet sufficient spinal cord injury is needed to allow experiments leading to development of therapeutic techniques and prediction of clinical outcome to be conducted. This study describes an experimental model for spinal cord injury that uses three different volumes of balloon inflation and durations of compression to create a controlled gradation outcome in adult dogs. Twenty-seven mongrel dogs were used for this study. A 3-french embolectomy catheter was inserted into the epidural space through a left hemilaminectomy hole at the L4 vertebral arch. Balloons were then inflated with 50, 100, or 150 µl of a contrast agent at the L1 level for 6, 12, or 24 h and spinal canal occlusion (SCO) measured using computed tomography. Olby score was used to evaluate the extent of spinal cord injury and a histopathologic examination was conducted 1 week after surgery. The SCO of the 50, 100, and 150 µl inflations was 22-46%, 51-70%, and 75-89%, respectively (p < 0.05). Olby scores were diminished significantly by a combination of the level of SCO and duration of inflation in all groups. Olby scores in the groups of 150 µl-12 h, 150 µl-24 h, and 100 µl-24 h were 0.5, 0, and 1.7, respectively. Based on these results, a SCO > 50% for 24 h, and > 75% for 12 h induces paraplegia up to a week after spinal cord injury