The tilapia fish (Oreochromis niloticus) has an important place in the aquaculture of the developing world. It is also a very useful laboratory animal, and readily lends itself to the transgenic technology. Through the use of reporter genes, a range of potential gene promoters have been tested in tilapia, both through transient and stable expression of the reporter construct. Using the transgenic technology, growth enhanced lines of tilapia have been produced. These fish have no abnormalities and offer a considerable growth advantage for future exploitation. It is however crucial that transgenic fish, to be exploited in aquaculture, be sterile, and various methods of achieving sterility are considered. These include triploidy, gene knock out of crucial hormone encoding genes via homologous recombination, and knock down of the function of the same genes via ribozyme or antisense technologies. Transgenic tilapia also offer the potential for exploitation as biofactories in the production of valuable pharmaceutical products, and this is also discussed.

In a long‐term growth trial, transgenic tilapia Oreochromis niloticus L. showed a 2·5‐fold increase in growth compared with non‐transgenic siblings. At 7 months, mean mass of transgenic tilapia was 653 g compared with 260 g for non‐transgenic siblings. A significant increase (P >0·01) in head: total length ratio, viscera‐somatic index and hepato‐somatic index was observed in transgenic fish. Female gonado‐somatic index (I G) was found to be lower in transgenics than non‐transgenic siblings in both mixed and separate culture conditions. Transgenic male I G values were found to be higher in mixed culture and lower in separate culture than that of their non‐transgenic siblings. Food conversion efficiency was more than 20% greater in the transgenic fish. In a second shorter‐term growth performance trial, the transgenic fish grew to about four times the size of their non‐transgenic siblings. A digestibility trial suggested that transgenic tilapia were more efficient utilizers of protein, dry matter and energy. Apparent digestibility of protein and apparent energy digestibility were higher in the transgenic fish.

A prospective 24 week study of 31 patients with active rheumatoid arthritis (18 women, 13 men) was undertaken to determine whether weekly intramuscular sodium aurothiomalate (gold) would influence delayed type cutaneous hypersensitivity (DTH) and other indices of cell mediated immunity. DTH to seven recall antigens was measured by Multitest on three occasions during the study. Twenty five patients completed the study. At entry 13 patients (12 female) were anergic, and no significant correlations were found between DTH and other clinical and immunological indices. Women showed a significantly greater depression of DTH than men. At week 24 only three of the patients were anergic with significant increase in mean DTH score being noted particularly to tuberculin, candida, and streptococcus. Improvement in DTH was observed in both gold responders and non-responders. In conclusion, patients with active rheumatoid arthritis show impairment of DTH, which is reversed by chrysotherapy. This effect is most apparent in women and appears to be relatively independent of the clinical response.

In a prospective 24 week study of 25 patients with rheumatoid arthritis (RA) weekly intramuscular (IM) sodium aurothiomalate resulted in a small but significant reduction in the circulating lymphocyte count. Analysis of absolute levels of pan T cells, T4 helper cells, T8 suppressor cells, T4/8 ratio, B cells, and major histocompatibility complex (MHC) class II positive cells showed reductions in these subsets, though these changes did not reach significance. At entry there was no association between circulating lymphocyte counts and subsets and clinical and laboratory indices which reflected disease activity, and during the study gold responders could not be differentiated from non-responders with regard to changes in lymphocyte counts and subsets. Thus this study suggests that weekly IM gold leads to a modest reduction in circulating lymphocyte numbers which involves most subsets. This effect appears to be independent of the clinical efficacy of this drug.

The elastic and inelastic scattering of neutrons from thorium is studied throughout the incident neutron energy interval 0.3 to 1.6 Mev. Fast time-of-flight techniques are utilized in conjunction with an electro-magnetic pulsing and bunching system for the production of short and very intense neutron bursts. The differential elastic cross section is determined as a function of incident neutron energy. The cross sections for inelastic scattering resulting in the excitation of residual nuclear levels at 50\ifmmode\pm\else\textpm\fi{}2, 170\ifmmode\pm\else\textpm\fi{}10, 720\ifmmode\pm\else\textpm\fi{}20, 790\ifmmode\pm\else\textpm\fi{}20, 820\ifmmode\pm\else\textpm\fi{}20, 1050\ifmmode\pm\else\textpm\fi{}50, and 1150\ifmmode\pm\else\textpm\fi{}50 kev are measured. The angular distribution of inelastically scattered neutrons resulting in the excitation of the lower two nuclear levels is determined. The measured individual inelastic excitation functions are combined to obtain the total inelastic scattering cross section as a function of incident neutron energy. The experimental results are compared with the results of other measurements.

The disintegration of ${\mathrm{Ge}}^{77}$ (12 hour) has been studied with the help of a magnetic lens spectrometer, coincidence counters, and scintillation counters. The beta-ray spectrum consists of three groups of whose endpoint energies are 2.196 Mev, 1.379 Mev, and 0.710 Mev. In addition there are 13 gamma-rays appearing in the product nucleus ${\mathrm{As}}^{77}$, some of which are internally converted. By coincidence counting techniques it has been shown that the beta-ray of energy 2.196 Mev does not go to the ground state but to an excited state 0.264 Mev above the ground state. A disintegration scheme is suggested.