The pathomorphology and pathogenesis of acute cardiovascular failure in swine. 2. Histopathologic findings in the myocardium of swine of different populations

Histopathological alterations of the myocardium (inflammatory processes, fibrolysis, fibronecrosis, dystrophic calcification, fatty degeneration of fibres, sarcosporidia) were recorded for quantitative evaluation from 200 hearts which had been collected from clinically intact pigs for slaughter of different populations (Leicoma, land race, Schwerfurt breed, Belgian land race). Both incidence and severity of myocardial damage in pigs of stress-sensitive populations were higher with significance than those in the less stress-sensitive Leicoma population oriented to breeding. The highest rate of pathological processes was recorded from hearts of the Schwerfurt breed. These alterations were interpreted as objectively measurable expressions of breed-dependent differences in cardiovascular stability. In this context, rates of damage were higher in hearts of low absolute mass.     

Relative contribution of initial root and shoot morphology in predicting field performance of hardwood seedlings

Single and multiple linear regression techniques were used to explain the capacity of initial seedling root volume (Rv) and first-order lateral roots (FOLR) relative to shoot height, diameter, and fresh mass to serve as important indicators of stock quality and predictors of first- and second-year height and diameter on an afforestation site in southern Indiana, USA. This was accomplished for northern red oak (Quercus rubra L.), white oak (Quercus alba L.), and black cherry (Prunus serotina Ehrh) seedlings graded into four Rv categories at establishment. Field survival was high (85–97%) for all species. Initial diameter, height, fresh mass, and Rv provided similar predictive ability of second-year field response for absolute height (R² = 0.59–0.77) and diameter (R² = 0.50–0.73) for both oak species. Initial seedling Rv was a better predictor of field response than FOLR for both oak species, though not for cherry. Multiple-variable models accounted for a greater proportion of the total variation in seedling field height and diameter than did single-variable equations. The high R² (up to 0.95) of regression models suggests field performance of these species can be reliably predicted and confirms the importance of initial seedling morphology in dictating early plantation performance.     

Defining competition vectors in a temperate alley cropping system in the midwestern USA: 2. Competition for water

A study was carried out in an alley cropping system in the Eastern Maize Belt of the United States with the objective of quantifying the competition for water between trees (black walnut (Juglans nigra L.) and red oak (Quercus rubra L.) and maize (Zea mays L.). Spatial and temporal variation in soil moisture, tree and maize rooting patterns, tree and maize water uptake, and maize leaf area expansion were determined in three treatments; barrier (polyethylene root barriers separating maize and tree roots), trench (trenching without a polyethylene barrier), and no barrier (control). Significant temporal variation in soil moisture was observed in both black walnut and red oak alley cropping systems. The barrier and trench treatments resulted in higher soil moisture in the maize alley and lower soil moisture in the tree row than the no barrier treatment. Uptake of water by maize was higher in the barrier than the no barrier treatment. However, tree water uptake was higher in the no barrier treatment than in the barrier treatment because tree roots utilized water from the maize alley. Maize leaf area was negatively impacted by water stress in the no barrier treatment. Quantification of rooting patterns revealed that maize and tree roots were concentrated in the top 30 cm soil layer where water fluctuations were greatest. The barrier and trench treatments successfully eliminated the belowground root competition between trees and maize and resulted in greater leaf area and higher grain yields than the no barrier treatment. Thus, competition for water rather than competition for light seems to be critical in defining the productivity and sustainability of this alley cropping system.This revised version was published online in November 2005 with corrections to the Cover Date.     

Determination of Feeder Cell‐Based Cellular Niches Supporting the Colonization and Maintenance of Spermatogonial Stem Cells from Prepubertal Domestic Cat Testes

Recently, isolation and in vitro culture of putative spermatogonial stem cells (SSCs) in the domestic cat have been conducted. However, the cellular niche conditions that facilitate the establishment and long‐term maintenance of feline SSCs (FSSCs) have not been described. Therefore, we investigated the type of feeder cells used to stimulate colony formation and growth of FSSCs among the various factors in the FSSC niche. Spermatogonial stem cells isolated from feline testes were cultured on mitotically inactivated testicular stromal cells (TSCs) derived from cats, dogs and mice, and mouse embryonic fibroblasts (MEFs). The formation and growth of colonies derived from SSCs cultured on each type of feeder cell were identified at passage 0, and the morphology, alkaline phosphatase (AP) activity and expression of SSC‐specific genes in surviving colonies were investigated at passage 4. Among these diverse feeder cells, TSCs from cat showed the greatest colony formation, growth and maintenance of FSSCs, and SSC colonies cultured by passage 4 showed a typical dome‐shaped morphology, AP activity and expression of SSC‐specific genes (NANOG, OCT4, SOX2 and CD9). Accordingly, these results demonstrate that feline TSCs could be used as feeder cells to support the establishment and maintenance of SSCs from domestic cats.     

The pathomorphology and pathogenesis of acute cardiovascular failure in swine. 3. Histopathologic findings in the myocardium of swine with transport-related cardiovascular insufficiency

Quantitative pathohistological investigations were performed on 300 samples of five different myocardial regions from 50 pigs with had suffered stress-related myocardial insufficiency on their transport to the slaughterhouse (transport exhaustion). The findings were compared to 1,200 myocardial samples from 200 clinically intact pigs for slaughter. Animals with transport-related damage exhibited with significance more and more severe inflammatory and degenerative myocardial alterations, such as round-cell infiltration, fiber necrosis, calcification, and fat infiltration. Many of these lesions had been manifest already prior to transport. Myocardially predamaged pigs were less capable than others of sustaining transport stress and were more predisposed to cardiac failure. Stress-related cardiovascular insufficiency, consequently, depended not only on direct stress but also on the general health condition of the myocardium. Causes and pathogenetic relevance of these alterations are discussed in some detail.