Familial aortic aneurysm in Leonberg dogs

A thoracic aortic aneurysm was diagnosed in a 6-month-old male Leonberg dog by use of radiography, transthoracic and transesophageal echocardiography, and magnetic resonance imaging. The aneurysm was associated with a twisted ascending aorta and dilatation of several other thoracic arteries (pulmonary trunk, brachiocephalic trunk, and left subclavian artery). Histologic examination of the aorta revealed cystic medial necrosis, with disruption of the elastic network, collagen fibers, and the muscle glycoprotein fibrillin-1. The dam and sire of the dog and 8 littermates were examined by use of transthoracic echocardiography. The sire and 1 male littermate also had an aneurysm of the ascending aorta. To the authors' knowledge, this is the first report of familial aortic aneurysm in dogs.     

Reproductive performance of camels (Camelus dromedarius) under pastoral management and its influence on herd development

Camels (Camelus dromedarius) produce milk and offspring and provide transport in pastoral husbandry systems in the Afro-Asian dryland belt. The aim of the present study was to investigate the reproductive performance of camels kept under pastoral management in northern Kenya. Using the Progeny History surveying technique, data were collected from 471, 287 and 416 adult Rendille, Gabra and Somali female camels including data on 1506, 789 and 1206 parturitions, respectively. Surveys took place from January to December 1995, but data refer to the 15-year production period preceding the survey. Age at first calving (AFC) was 58.4±1.0 months (LSMeans±S.E.), 63.0±1.1 months and 68.4±1.3 months for the Somali, Rendille and Gabra camels, respectively.The mean calving interval was similar for all three populations with 27.3±0.6 months (LSMeans±S.E.) for Rendille camels, 28.0±0.6 months for Gabra (n=500) and 28.4±0.6 months for Somali camels. The annual calving rate varied between 33% and 46% in the Somali, 19% and 44% in the Gabra and 8% and 86% in the Rendille camel population. Calf mortality rate averaged 25%, 22% and 27% in Rendille, Gabra and Somali camel calves, respectively, and showed highest variation between the years in the Rendille system (5% to 60%).The number of adult breeding females increased by about 20% over a simulation period of 10 years using the status quo reproductive parameters and by about 70% with improved AFC and CI (excluding AFC>78 months and CI>36 months). The results reveal the usual and unusual variation in the reproductive parameters over different years and in the different systems. It is concluded that eliminating unusual variation is a promising way to enhance herd development and reduce risk in the production systems.     

Landscape pattern in topographically complex landscapes: issues and techniques for analysis

Ecological research provides ample evidence that topography can exert a significant influence on the processes shaping broad-scale landscape vegetation patterns. Studies that ignore this influence run the risk of misinterpreting observations and making inappropriate recommendations to the management community. Unfortunately, the standard methods for landscape pattern analysis are not designed to include topography as a pattern-shaping factor. In this paper, we present a set of techniques designed to incorporate the topographic mosaic into analyses of landscape pattern and dynamics. This toolbox includes adjustments to classic landscape indices that account for non-uniform landscape topography, indices that capture associations and directionality in vegetation pattern due to topographic structure, and the application of statistical models to describe relationships between topographic characteristics and vegetation pattern. To illustrate these methods, we draw on examples from our own analysis of landscape pattern dynamics in logged and unlogged forest landscapes in southwestern British Columbia. These examples also serve to illustrate the importance of considering topography in both research and management applications.This revised version was published online in May 2005 with corrections to the Cover Date.     

Presence of residual material following mini-hemilaminectomy in dogs with thoracolumbar intervertebral disc extrusion

Presence of residual material following mini-hemilaminectomy in dogs (n = 9) with spontaneous thoracolumbar intervertebral disc extrusion was prospectively investigated. Volume of extruded disc material within the vertebral canal and the proportion of residual material were determined using pre- and post-operative magnetic resonance imaging. The degree of spinal cord compression, proportion of extradural material considered hemorrhage, and invasion of the articular facets were also determined. Residual material was identified in 44% of the mini-hemilaminectomies. The median percentage of residual material calculated was 7.7% of the preoperative volume. No observed effect of surgical side or site, proportion of extradural material considered hemorrhage, patient weight, and duration of clinical signs was detected.     

Deficit in attachment behavior in mice lacking the mu-opioid receptor gene

Endogenous opioid binding to micro receptors is hypothesized to mediate natural rewards and has been proposed to be the basis of infant attachment behavior. Here, we report that micro-opioid receptor knockout mouse pups emit fewer ultrasonic vocalizations when removed from their mothers but not when exposed to cold or male mice odors. Moreover these knockout pups do not show a preference toward their mothers' cues and do not show ultrasonic calls potentiation after brief maternal exposure. Results from this study may indicate a molecular mechanism for diseases characterized by deficits in attachment behavior, such as autism or reactive attachment disorder.     

Structure, chemical composition, and xylanase degradation of external layers isolated from developing wheat grain

The external layers of wheat grain were investigated during maturation with respect to chemical and structural features and xylanase degradability. Cytochemical changes were observed in the isolated peripheral tissues of the wheat grain at four defined stages following anthesis. Marked chemical changes were highlighted at 11 days after anthesis, for which protein and lipid contents varied weakly. The profile of esterified ferulic acid showed large variation in the maturing peripheral layers of grain in contrast to the deposition of ferulate dimers, p-coumaric and sinapic acids. Lignin was monitored at the latest stages of ripening, which corresponds to the cessation of reserve accumulation in the grain. Arabinoxylans (AX) reached a maximum at 20 days and did not display any significant change in arabinosyl substitution proportion until ripeness. When submitted to xylanase, all outer layers were similarly altered in the proportion of soluble AX except for the peripheral tissues of the 11-day-aged wheat grain that had very little AX. Aleurone and nucellar layers were mostly degraded, whereas pericarp stayed intact at all stages of maturation. This degradation pattern was connected with the preferential immunolocalization of xylanase in aleurone and nucellar layers irrespective of the developmental stages. Further chemical examination of the enzyme-digested peripheral tissues of the grain supports the facts that ferulic ester is not a limiting factor in enzyme efficiency. Arabinose branching, ferulic dimers, and ether-linked monomers that are deposited early in the external layers would have more relevance to the in situ degradability of AX.