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Putative quantitative trait loci for heat tolerance have been studied in outbred strains of rainbow trout unselected for the trait using simple-sequence repeat markers associated with upper thermal tolerance (UTT) in backcrosses of lines selected on the trait. The in general stronger marker-trait associations found in male parents may be partially caused by reduced chromosomal recombination rates in male salmonids vs females. Results indicate effects of a QTL on a fitness-related trait in unselected populations of the trout.

A candidate gene mapping approach applied to existing quantitative trait loci (QTL) for spawning date in rainbow trout (oncorynchus mykiss) is ascertained whether these genes potentially account for any QTL effects. The results suggests that arylalkylamine N-acetlytransferase as a regulator of melatonin production is not a major gene influencing spawning time in the rainbow trout cross hence, contributes to the lack of evidence supporting the physiological role of melatonin in reproduction.

Heritabilities and genetic correlations among growth-related traits of two cultured strains (Rainbow Springs and Spring Valley) of rainbow trout Oncorhynchus mykiss were estimated using restricted maximum likelihood methods with a three-generation pedigree. Heritability was high (>0·50 ± 0·03) for body mass and condition factor but moderate (0·35 ± 0·04) for age at sexual maturity in males. Body mass and age at sexual maturation were phenotypically correlated in the families of one experimental strain, Rainbow Springs, and had a positive genetic correlation (0·26 ± 0·03) across families from both test strains (Rainbow Springs and Spring Valley). This indicates that faster growing individuals were more likely to mature at 2 years of age than slower growing individuals in the two hatchery strains investigated. Microsatellite markers of body mass quantitative tract loci (QTL) were reconfirmed as being located on linkage groups B, G, N, 5 and new markers on Oi were detected. Some QTL effects were restricted to specific sampling dates suggesting temporal expression of QTL. QTL for condition factor were limited to linkage group G in both strains. Three suggestive QTL for precocious maturation mapped to similar regions as those for body mass in the Rainbow Springs families while no associations were evident in the Spring Valley families. The results suggest that these regions may play a role in the basis for genetic and phenotypic correlations between body mass and precocious maturation in this species. [ABSTRACT FROM AUTHOR]

Presents a study which determined the relationship between the reproductive success and body size of male Atlantic cod, Gadus morhua L. Methodology; Results; Discussion.

Mice were given a single inoculation of polyoma virus at birth and then orchidectomised or oophorectomised. Unoperated groups received polyoma virus alone whilst further males received testosterone, and females received oestradiol thrice-weekly in addition to polyoma virus inoculation. All groups were then observed over the succeeding 370 days for the development of tumors of the submandibular and parotid salivary glands. Polyoma virus inoculation selectively induced salivary gland tumors in 70% of male animals and 30% of female animals given polyoma virus alone. Testosterone therapy increased the salivary tumor frequency from 69-90% whilst orchidectomy reduced the tumor frequency to 50%. Oophorectomy or oestrogen therapy did not significantly alter the salivary gland tumor frequency in females but oestrogen therapy did result in the development of second primary tumors of breast in 60% of female animals bearing salivary gland tumors. The role of androgens in the development of virally induced salivary gland tumors is discussed as are the possible mechanisms responsible for the development of second primary tumor of breast. [ABSTRACT FROM AUTHOR]

Reports the importance of hematological screening of outpatients with recurrent aphthous stomatitis in Glasgow Dental Hospital in Scotland. Effectivity of specific replacement therapy; Determination of the cause of mineral deficiencies; Identification of associated conditions.

Comments on several topics on medicine. Assumptions regarding the reconstruction of general practice; Evidence of low prevalence of insulin dependent diabetes among Asian diabetics; Evaluation of virological assays and reagents.

Presents letters related to medicine published in the 'British Medical Journal.' Relevance of antithyroid drugs to the treatment of Graves' disease; Role of deformity of the nasal septum; Success of the seat belt campaign.

Discusses a research about the isolation of microsatellite-containing DNA from Arctic charr. Suggestion that primers were screened for their ability to amplify DNA from representatives of the genera in the salmonidae; Number of alleles observed in Arctic charr and other salmonid species.