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Thyrotropin releasing hormone (TRH) stimulation tests were carried out on a number of horses, including one clinically affected horse whose age and clinical signs suggested that a pituitary adenoma was most unlikely. The results of these tests indicated that, according to criteria published overseas, the majority of these horses had pituitary adenomas. The fact that clinically normal or affected horses may have marked increases in cortisol concentrations indicates that the TRH stimulation test is not suitable for the diagnosis of pituitary adenoma. Other tests, including alterations in glucose metabolism and, if available, ACTH measurements, are probably more useful for diagnosis. However, most diagnoses will probably rely upon the characteristic clinical signs.

The most common coupling between a prism and a waveguide requires a gap between the prism and the waveguide. The modes in the waveguide are guided modes. We show that discrete substrate modes may be excited if the waveguide film is directly deposited onto the prism. These discrete substrate modes have many similarities to guided modes.

A cat was presented to a veterinary clinic with a severe pleural effusion from which an organism later identified as an Actinomyces spp., probably A. odontolyticus, was isolated along with Bacteroides mehnogenicus. It was successfully treated with surgical drainage and a combination of amoxycillin and sulphadiazine/trimethoprim. The fluid was cytologically examined to obtain a provisional diagnosis and to allow treatment to be initiated while the organisms were cultured and identified. The cat is now clinically normal except for slight abdominal respiration, presumably resulting from adhesions following the severe infection.

The properties of a sequence of tetrahedrally coordinated semiconducting glasses CdGexAs2 are reviewed. Measurements of the optical band gap, d.c. conductivity, elastic constants and glass transition temperature as a function of pressure are reported for a glass with α≅0·5. The known properties are consistent with a p to n transition as x is increased above 0·5.

Serum gamma glutamyl transpeptidase (GGT) levels in blood samples taken from normal calves which bad suckled colostrum were much higher than those found in healthy adult cattle. Levels of over 60 times the normal adult level were observed. These high levels of GGT took approximately 5 weeks to decline to adult values. Calves which appeared to have not received or absorbed colostrum had GGT levels which would be considered normal in adult cattle. A calf with serum gamma globulin levels which indicated an intermediate amount of colostrum absorption had a level of GGT which was intermediate between that expected for normal adult cattle and that found in calves which had more fully absorbed colostrum. The mean GGT level observed in colostrum from 6 newly-calved cows was over 800 times the mean serum GGT level of the same 6 cows. It therefore appears most likely that GGT is concurrently absorbed with colostrum by calves and this gives rise to the very high levels seen in normal calves. Calves with very high levels of serum GGT also had raised levels of alkaline phosphatase (AP) which slowly declined but never reached normal adult levels within the 53-day period of observation. It therefore appears that high levels of both GGT and AP are achieved by calves at the time of colostrum absorption and it is concluded that clinical interpretation of serum GGT and AP levels in young calves is closely dependent upon parallel knowledge of their serum gamma globulin levels.

The optical constants e1 and e2 of lithium-ammonia solutions in the metallic concentration range and on the metallic end of the Mott transition region have been measured using ellipsometry. The photon energies varied from 0.6 ev to 2.5 ev while the Fermi energies of the solutions are in the range 0.4 to 0.9 ev. The results in the metallic range are in qualitative agreement with the simple Drude theory but show wavelength dependent relaxation times presumably because of the relatively high photon energies. An absorption in the near IR distorts the results for the solutions near the Mott transition (e.g., e1 shows a minimum and remains >0). A peak in Im (1/e), as calculated from e1 and e2, occurs at energies within 20% of those predicted from the relaxation time and carrier density. The peak is sharp for the most concentrated solutions but broadens as the Mott transition is approached. These results support the view that these solutions are simple metals though the electron density is low relative to common...