Clinical, biochemical and immunological studies of feline thyroid function

Double antibody radioimmunoassays for thyroxine (T4) and triiodothyronine (T3) were optimised and validated for use in cats. Serum total T4 concentrations of 318 and total T3 concentrations of 299 healthy cats were measured. In both sexes, T4 concentrations tended to decrease until five years of age and then rise again. For any given age, females and neutered females tended to have significantly higher T4 values than males and neutered males. Pedigree animals tended to have higher concentrations of T3 at any given age than cross-bred cats. Animals living in the same environment had significantly similar T4 and T3 concentrations respectively which, for T3 only, appeared to be due to a definite genetic component.netic component. There was no obvious difference in the results of the T4 uptake test between euthyroid, hyperthyroid and hypothyroid cats. In normal feline serum, after agarose gel electrophoresis with tris-maleate buffer at pH 7.4, T4 was bound only to albumin and alpha-globulin, and feline T3 mainly to alpha-2- globulin and beta-globulin. In thyrotoxicosis, the percentages of T4 bound to albumin and alpha-globulin were decreased and increased respectively. These changes were not the result of hyperthyroxinaemia per se, nor to interference of T4 binding to albumin by non-esterified fatty acids. Changes in iodothyronine binding were seen in two euthyroid cats with elevated serum T3 and/or T4 concentrations, in two cats with euthyroid diseases, but not in two experimental hypothyroid animals.The historical, clinical and diagnostic features of 74 hyperthyroid cats are presented. Approximately 70 per cent of cases had unilateral goitre. Surgical treatment for both unilateral and bilateral lobe involvement was effective but post-operative hypocalcaemia was common in the latter group. Hypothyroidism was induced in two cats using and the resultant state monitored for 91 weeks. Both cats developed sub-normal rectal temperatures, reduced heart rates and bilaterally symmetrical alopecia and hyperpigmentation of the distal pinnae. Hyperkeratosis, myxoedema and apocrine gland changes were found in skin biopsies. Serum gamma-globulin concentrations increased progressively after thyroid ablation.The historical and clinical features of 26 cases of feline endocrine alopecia (FEA) are described. A raised blood eosinophil count was highly reliable in distinguishing between FEA and physically similar conditions. Seventy-three per cent of cases responded totally to treatment with T3. The thyroid stimulating hormone (TSH) stimulation test was optimised for cats. Six hours after TSH administration, cats with FEA had significantly lower, and absolute increases in, T4 concentrations than healthy cats. The serum T4 and T3 concentrations of the experimental hypothyroid cats failed to increase after TSH but a single hyperthyroid cat responded normally.Thyroid and antinuclear antibodies were demonstrated in serum from ten and four of 29 hyperthyroid cats respectively, using the indirect immunofluorescence test with normal cat thyroid as substrate. Fifteen healthy control cats were negative for autoantibodies. Animals with strong positive results for thyroid antibodies were significantly more likely to have bilateral goitre with lymphocytic infiltrations than other thyrotoxic cats

Anchorage and residual bond characteristics of 7-wire strand

© 2017 Elsevier Ltd The periodic assessment of our existing concrete infrastructure is a crucial part of maintaining appropriate levels of public safety over long periods of time. It is important that realistic predictions of the capacity of existing structures can be made in order to avoid unnecessary and expensive intervention work. Assessment is currently undertaken using codified models that are generally readily applied to infrastructure with simple geometric and reinforcement details that conform to design methods for new structures. This approach presents two significant challenges for prestressed structures: (1) design and construction practice has changed significantly in the past 50 years, and modern codified approaches can be incompatible with historic structures; and (2) deterioration of exposed soffits can lead to reduced cover to internal prestressing strand. Unless appropriate reductions are used in assessment of a structure with such problems, unnecessary load restrictions, or major strengthening or reconstruction work may be required, despite having carried a full service load since its construction. There are currently no widely accepted methods for the prediction of peak and residual capacities in prestressed concrete beams with inadequately detailed 7-wire strand. This paper presents a completely new prediction methodology, validated against new experimental results from 31 novel semi-beam tests. The proposed models for peak load, residual load, and bond stress-slip modelling provide reliable, accurate, and conservative results. Their results demonstrate feasible and appropriate capacity reduction factors for use in the assessment of existing concrete infrastructure

Phenetic distances in the Drosophila melanogaster-subgroup species and oviposition-site preference for food components

Oviposition-site preferences (O.S.P.) have been investigated in females of six sibling species of the Drosophila melanogaster subgroup. O.S.P. were determined for standard food components and yeast genotypes. Females of all species showed a strong preference for complete medium and avoidance of pure agar as an egg-deposition site.\ud \ud Ecological trees of the species on the basis of rank correlations were constructed. In ‘no-choice’ situations they agree with phylogenetic trees obtained by different means but in ‘choice’ situations they do not agree too well.\ud \ud All species showed a high egg production on live yeast compared with standard medium (with killed yeast) and D. erecta females demonstrated discrimination between yeast genotypes. Niche breadth calculated from survival on the sterol mutant yeasts correlated fairly well with phylogenetic trees

Survivability Is More Fundamental Than Evolvability

For a lineage to survive over long time periods, it must sometimes change. This has given rise to the term evolvability, meaning the tendency to produce adaptive variation. One lineage may be superior to another in terms of its current standing variation, or it may tend to produce more adaptive variation. However, evolutionary outcomes depend on more than standing variation and produced adaptive variation: deleterious variation also matters. Evolvability, as most commonly interpreted, is not predictive of evolutionary outcomes. Here, we define a predictive measure of the evolutionary success of a lineage that we call the k-survivability, defined as the probability that the lineage avoids extinction for k generations. We estimate the k-survivability using multiple experimental replicates. Because we measure evolutionary outcomes, the initial standing variation, the full spectrum of generated variation, and the heritability of that variation are all incorporated. Survivability also accounts for the decreased joint likelihood of extinction of sub-lineages when they 1) disperse in space, or 2) diversify in lifestyle. We illustrate measurement of survivability with in silico models, and suggest that it may also be measured in vivo using multiple longitudinal replicates. The k-survivability is a metric that enables the quantitative study of, for example, the evolution of 1) mutation rates, 2) dispersal mechanisms, 3) the genotype-phenotype map, and 4) sexual reproduction, in temporally and spatially fluctuating environments. Although these disparate phenomena evolve by well-understood microevolutionary rules, they are also subject to the macroevolutionary constraint of long-term survivability

Genetics of Microenvironmental Sensitivity of Body Weight in Rainbow Trout (Oncorhynchus mykiss) Selected for Improved Growth

Microenvironmental sensitivity of a genotype refers to the ability to buffer against non-specific environmental factors, and it can be quantified by the amount of residual variation in a trait expressed by the genotype’s offspring within a (macro)environment. Due to the high degree of polymorphism in behavioral, growth and life-history traits, both farmed and wild salmonids are highly susceptible to microenvironmental variation, yet the heritable basis of this characteristic remains unknown. We estimated the genetic (co)variance of body weight and its residual variation in 2-year-old rainbow trout (Oncorhynchus mykiss) using a multigenerational data of 45,900 individuals from the Finnish national breeding programme. We also tested whether or not microenvironmental sensitivity has been changed as a correlated genetic response when genetic improvement for growth has been practiced over five generations. The animal model analysis revealed the presence of genetic heterogeneity both in body weight and its residual variation. Heritability of residual variation was remarkably lower (0.02) than that for body weight (0.35). However, genetic coefficient of variation was notable in both body weight (14%) and its residual variation (37%), suggesting a substantial potential for selection responses in both traits. Furthermore, a significant negative genetic correlation (−0.16) was found between body weight and its residual variation, i.e., rapidly growing genotypes are also more tolerant to perturbations in microenvironment. The genetic trends showed that fish growth was successfully increased by selective breeding (an average of 6% per generation), whereas no genetic change occurred in residual variation during the same period. The results imply that genetic improvement for body weight does not cause a concomitant increase in microenvironmental sensitivity. For commercial production, however, there may be high potential to simultaneously improve weight gain and increase its uniformity if both criteria are included in a selection index