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The aims of the work reported in this thesis were threefold; firstly, to investigate the effect of experimental exposure to polycyclic aromatic hydrocarbons (PAHs) on the immune response of dab (<I>Limanda limanda</I>), a sentinel species of flat fish for pollution studies, and rainbow trout (<I>Oncorhynhus mykiss</I>); secondly, to then go into the field to investigate the effects of exposure to PAHs on dab immunity through a major oil spill and thirdly, to increase current knowledge on the cellular immune functions of dab so as to provide better assays for biomonitoring purposes. Chapter 1 of this thesis is a general introduction to immunotoxicology, subspeciality of toxicology, which described brief accounts for both immunology and toxicology. Some brief accounts for the use of fish (lower vertebrates) in a pollution monitoring programme and the toxicology aspects of polycyclic aromatic hydrocarbons, were also given. In chapter 2, a laboratory exposure of animals to oil-contaminated sediment was established where four doses of diesel oil-based drilling mud used, i.e. 4, 8 (seen 500m from oil exploration platforms in the North Sea), 12 and 16% (w/w), with two exposure times employed, i.e. 2 and 4 weeks. Haematocrits and lymphocyte numbers tend to increase with low diesel oil doses, whereas high doses (particularly with longer exposure) gave significantly decreased values. Serum lysozyme levels were decreased, but serum bactericidal and anti-protease activities tended to increase following exposure. Kidney phagocyte respiratory burst and neutrophil migration activity also showed a trend to lower levels relative to control fish, whereas the number of antibody-secreting cells were increased with high drilling mud concentration. Lastly, there was a dose-dependent hepatomegaly. In chapter 3, rainbow trout were injected intra-peritoneally with an extract obtained from diesel oil-based drilling mud. Fish were exposed to different doses of extracts (made up to 2.4 mL/kg with olive oil), i.e. 0, 0.6, 1.2 and 2.4 mL/kg body weight (B.W.), for 6 weeks in the dose effect experiment.

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The present paper explores vicarious emotional conditioning and some variables of dependency that may influence the rate of conditioning. Volunteer introductory psychology students were administered the Edwards Personality Preference Schedule using the deference and autonomy scales as criteria for classifying subjects as dependent or independent. Ten females and four males were randomly chosen for each group. All subjects underwent adaptation to a tone which served as a conditioned stimulus. Ten acquisition trials followed where each subject was exposed to witnessing an experimental stooge emiting pain cues to a fake shock. Six test trials were presented where the conditioned stimulus was presented alone. The measure of emotional reaction was the subject’s GSR. Mann-Whitney-U-Test was performed on the percent of GSRs elicited and a t-test on the GSR and BSR magnitude. The results indicated that dependent individuals elicited significantly more GSRs during the acquisition and test trials. No significant difference was found on GSR or BSR magnitudes. Possible relationships between introversion/extroversion and dependency/independency are presented and confounding variables are discussed.

The aim of this study was to determine whether breast milk had a stimulating effect on the development of immune responses in infants. Breast- and bottle- fed infants were studied from birth to 9 months of age. Several significant differences in immune responses were found between the groups. These differences were related to age and fell into two main time periods. In the early neonatal period, lymphocytes from breast-fed infants showed significantly greater spontaneous proliferation and proliferative responses to the T cell mitogen PHA to vitro than cells from bottle-fed infants. This may be due to a stimulatory effect to vivo of the growth factors and lymphokines in human milk acting on T cells and/or their precursors. Serum immunoglobulin levels did not however, reflect this increased lymphocyte responsiveness and although salivary IgM and IgA levels were significantly increased in the breast-fed infants at 6 days of age, this may have been due to residual milk immunoglobulins. In contrast, by 3 to 9 months of age, the cells from the bottle-fed group showed significantly greater to vitro proliferation of all classes of lymphocytes than the cells from the breast- fed infants. Salivary IgM and IgA levels and serum IgM antibodies to commensal gut organisms were also significantly higher in bottle-fed infants at this time. This indicated a higher rate of to vivo stimulation of the immune system in bottle-fed infants. It is suggested that this is due to an increased exposure of bottle-fed 'infants to antigenic material at mucosal surfaces and a greater uptake of these local antigens into the systemic circulation. Breast-feeding may therefore have contrasting effects on the development of immune responses, a stimulating effect by growth factors, particularly in the early immature period, and a suppressive effect resulting indirectly from exclusion of antigens (including those of a potentially harmful nature).

This study aimed to investigate the response of lentil genotypes to different water regimes, providing guide lines, through partitioning the variation, for a selection program for adaptation to irrigated conditions. The research was divided into two main areas; 1) The overall variation in the crop was partitioned into genotypic, environmental and genotype-environmental components in an analysis of adaptation over seasons, irrigation regimes and locations; 2) The genotypic variation was partitioned into its various genetic components in an inheritance study using the dial lei mating system. Pronounced progress should be expected from selection for number of pods/plant, 100 seed weight and straw yield/plant traits, which showed high estimates of h(^2)(_b.s), C.G.V. and G.S. The two former traits correlated strongly and positively with seed yield, which allowed their use in indirect selection for seed yield. The 35 genotypes used in this study showed wide genetic diversity, allowing selection of high yielding genotypes under irrigation. Environmental variation in water supply, temperature and soil type was found to exert a profound effect on variation in characters measured. This suggests the possibility of raising yield levels through improved management practices. In this study, irrigation repeated twice increased seed yield by 19% over no irrigation, at the same location, and increased the yield by 300% in comparison with a dry location. Seed protein quality was influenced by environments and genotypes. Electrophoretic studies showed that the number and position of the bands could be used to identify genotypes. Four genotypes showed response to irrigation and could be recommended as promising entries. An anatomical study showed that large air spaces formed in the roots of a responsive genotype:, which could be used as a selection criterion for positive response to irrigation. Seed yield/plant exhibited 31.8% heterosis and showed a predominant role of non-additive genetic variance. Due to the significance of the non-additive effect, the superior F(_1)'s may be expected to throw out desirable transgressive segregants, provided that the complementary genes and epistatic effects included in the non-additive component are coupled in the same direction to maximize seed yield. Five F(_2) crosses showed superiority in seed yield and SCA effects. These crosses should be carried forward in lentil breeding programs.

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