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Since individual chromosomes can be accurately identified by new banding techniques, atebrin fluorescence was used for chromosome analysis in six cell lines and two primary outgrowths derived from human malignant melanoma. Gross aneuploidy was seen in all specimens, but each culture contained at least 1 distinctive marker chromosome specific for that cell line in 87 to 100% of metaphases. One of the primary explants contained a marker that was demonstrable in fresh tissue and persisted through 2 weeks of culture. The same marker was found in all metaphases from 2 different metastases, but skin fibroblasts from the same patient had a normal chromosome complement. No common marker for human melanoma was found, but in 6 of the 8 cultures the most frequently found marker was formed by a brightly banded chromatid addition. Relative polysomy for Chromosome 7 was found in 7 of the 8 cultures and, for Chromosome 22, in 8 of the 8 cultures. The frequency of polysomy of Chromosomes 7 and 22 was significant at the 5% level.

The pH, PO2 and the number of viable bacteria per ml of abomasal fluid were recorded before and after administering large doses of infective larvae of H. contortus to sheep. Highly significant increases were observed in the pH, in numbers of viable bacteria and in the proportion of oxygen-sensitive bacteria in the abomasal fluid during the first 10 to 14 days of infection. At the same time a decrease in the abomasal fluid PO2 was recorded. Subsequently a slow recovery of pH, PO2 and bacterial numbers to pre-infection values ensued. The microbiological and physiological changes occurring in the abomasum of sheep after infection with H. contortus are discussed with reference to these results.

Cultures of Pseudomonas spp. strains P10, P12 and P15 grown in whole milk which contained approximately 1 x 10(8) viable bacteria ml-1 demonstrated near linear increases in the concentration of short-chain free fatty acids and trichloroacetic acid soluble free amino groups at 20 degrees C, following either ultra high temperature (UHT) treatment (140 degrees C for 5 s) or dual heat treatments (140 degrees C followed by either 57, 60 or 65 degrees C). The dual heat treatments reduced the rates of lipolysis and proteolysis compared to the UHT treatment by up to 25-fold. The dual heat treatment utilizing 60 degrees C for 5 min also effectively limited both lipase and proteinase activities in raw milk culture samples which had contained either 6 x 10(6), 5 x 10(7) or 1 x 10(8) viable bacteria ml-1. In this system enzyme activities were reduced by up to 10-fold following dual heat treatment compared to UHT treatment alone.

Cultures of Pseudomonas P46 grown in whole milk to contain approximately 2 X 10(7) or 1 X 10(8) viable cells ml-1 before ultra high temperature (UHT) treatment (140 degrees C for 5 s) demonstrated near linear increases in the concentration of short-chain free fatty acids (FFA) during storage at 20 degrees C. However with 5 X 10(6) cells ml-1 before UHT heat treatment there was no detectable increase in these FFA levels over a 6-month storage period. A novel heat treatment (140 degrees C for 5 s followed by 60 degrees C for 5 min) reduced the rate of production of volatile FFA to less than 10% of the rates achieved after the normal UHT treatment.