A large proportion of the samples tested in routine diagnostic microbiology laboratory are urine samples. The gold standard is bacterial culture, but a high proportion of samples cultured are negative. Unnecessary testing can be reduced and an improved service provided by an effective screening test. The Sysmex UF-100 flow cytometer has been developed to count cells and casts accurately in urine samples. Its performance in a screening test was compared with bacterial culture by using 1005 consecutive urine samples, and cut-off criteria were established. Cut-off values of 3000 bacteria/ml and 111 WBC/ml provided the best discrimination. Of 1005 samples, 606 (60%) would be cultured. Sixteen samples that were not selected according to these criteria were culture positive. This was considered acceptable for our routine use. The use of a testing algorithm incorporating the Sysmex UF-100 flow cytometer has improved the quality and efficiency of urine testing within the routine microbiology laboratory. U rinary tract infection is common within community and hospital populations. About 50% of women state that they have experienced one infection in their lifetime and 27-48% have had recurrent infections.

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1. Ovalbumin glycopeptides, freed from all amino acids other than aspartic acid and a small proportion of leucine by repeated digestion with Pronase, were hydrolysed by 1-aspartamido-beta-N-acetylglucosamine amidohydrolase (glycoaspartamidase) to the corresponding oligosaccharides. The glycoaspartamidase did not attack ovalbumin itself. 2. Ovalbumin, with mannose/hexosamine ratio 5:4, lost 1.5moles of N-acetylglucosamine and more than 2moles of mannose after incubation with alpha-mannosidase and beta-N-acetylglucosaminidase respectively. 3. In ovalbumin glycopeptides with approximate mannose/hexosamine ratios 5:3 and 5:4, one and two N-acetylglucosamine residues respectively were accessible to the action of beta-N-acetylglucosaminidase. 4. A mixture of alpha-mannosidase and beta-N-acetylglucosaminidase, acting on an ovalbumin glycopeptide with mannose/hexosamine ratio 5:3.7, removed nearly 4moles of mannose and 1.5moles of N-acetylglucosamine. 5. alpha-Mannosidase removed about 1.5moles of mannose from the ovalbumin oligosaccharide with mannose/hexosamine ratio approx. 5:3. The subsequent action of beta-N-acetylglucosaminidase liberated less than 1mole of N-acetylglucosamine and made at least 1mole further of mannose accessible to alpha-mannosidase action. 6. It is concluded that the carbohydrate moiety of ovalbumin is linked through a glycosyl group to asparagine. In a molecule with mannose/hexosamine ratio 5:4, there are two beta-N-acetylglucosamine residues linked together in a terminal position, followed by alpha-mannose. There is also present a side chain containing two alpha-mannose units.

1. alpha-Mannosidase from the limpet, Patella vulgata, was purified nearly 150-fold, with 40% recovery. beta-N-Acetylglucosaminidase was removed from the preparation by treatment with ethanol. The final product was virtually free from beta-galactosidase. 2. Limpet alpha-mannosidase was assayed at pH3.5 and at this pH it was necessary to add Zn(2+) for full activity. At pH5, the enzyme had the same activity in the presence or absence of added Zn(2+). 3. On incubation at acid pH, the enzyme underwent reversible inactivation, which was prevented by adding Zn(2+). 4. EDTA accelerated inactivation and the addition of Zn(2+) at once restored activity. No other cation was found to reactivate the enzyme. 5. Cl(-) had an unspecific effect on hydrolysis by limpet alpha-mannosidase. It increased the rate of reaction with substrate. The anion did not prevent or reverse inactivation by EDTA. 6. It is concluded that alpha-mannosidase is a metalloenzyme or enzyme-metal ion complex, dissociable at the pH of activity, and that it requires Zn(2+) specifically.

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