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The value of tablets and paper discs as reservoirs of antimicrobial agents for use in sensitivity testing was compared. Antibiotics that were unstable in paper discs showed no demonstrable loss of activity in tablets over a period of 50 days under adverse storage conditions. The antibiotic content of commercially prepared tablets is very high in comparison with the accepted content of paper discs used in Britain, but not all of the agent is released from tablets during tests. Comparison of the size of zones of inhibition around tablets and standard paper discs indicated that the amount of the various agents released from the tablets varied between 2-6% and 69% of the stated content. In tests of the sensitivity of a range of common pathogenic organisms, the results obtained with the tablet method--when interpreted as recommended by the manufacturer--were generally similar to those obtained with a paper disc method commonly used in British laboratories. In 47% of tests with aminoglycoside antibiotics, however, strains sensitive by the disc method were 'intermediate' or resistant by the tablet method. As with paper discs, it was necessary to press the tablets on to the medium. With adjustment of the 'effective antibiotic content of tablets to bring it into line with the accepted content in paper discs, the stability of antibiotics in the tablets might make them an acceptable alternative to paper discs.

Because they are cumbersome, tests to determine the quantitative susceptibility of organisms to antimicrobial drugs are not performed routinely in many diagnostic laboratories. This paper describes a simple method of incorporating the antimicrobial drug in agar. It is an adaptation of the Rolinson and Russell technique which allows the determination of minimum inhibitory concentrations (MIC) of antimicrobial drugs for a large number of organisms. Results are comparable with those obtained when the standard agar dilution method is used. Strains of aerobic Gram-negative bacilli were tested by both methods using ampicillin (86 strains), cephaloridine (72 strains), trimethoprim (72 strains), and gentamicin (72 strains). Of the 302 tests thus performed, a difference in MIC of more than one double dilution was noted in only 11 tests. With one strain of Pseudomonas aeruginosa, however, it was not possible to detect ampicillin resistance by the method described in this paper.

Materials for wrapping surgical dressings were studied by a method which measured the recontamination rate in packs stored for periods of up to several weeks. Of the materials tested a thick crêpe paper was better than calico and balloon cloth fabrics. Dressings wrapped in paper were not significantly contaminated after storage in dusty places for periods of up to three weeks. For added protection during handling and for convenience in transport and storage, paper packs may be sterilized and kept in paper-lined cartons. The shelf life in good storage conditions would be many weeks at least.

The protein and lipid electrophoresis patterns of lymph and various body fluids have been examined. Chylous fluids produce a characteristic lipid pattern with a dense deposit at the origin and a lipid trail. The value of centrifuging turbid fluids at high speed before electrophoresis is stressed.

A quantitative paper electrophoresis method for the separation of haemoglobins A and A(2) is described. The possible sources of error and the accuracy of the method have been investigated. The normal range for haemoglobin A(2) by this method is 1.3% to 4.3% of the total haemoglobin concentration. Good clinical correlation has so far been obtained.

Satisfactory spore preparations for testing hospital sterilizers can be made from and comparatively simple methods for loading and drying the papers are considered to be valid. Each batch of spore papers should be calibrated by plotting dose-response curves for exposure to steam. A minimum standard in terms of the L.D.50 to moist heat is proposed and confidence limits suggested when such papers are used in pairs or small multiples. [ABSTRACT FROM PUBLISHER]

A simple paper chromatographic method was found to be effective for the study of phenylketonuria and tyrosyluria. It proved to be much more reliable than conventional tests for the detection of abnormal amounts of ketoacids in urine and was suitable and convenient for following the effects of dietary variations on the excretion of these compounds. Information obtained about ketones other than those of primary importance to the conditions studied included confirmation of the excretion of p-hydroxyphenylpyruvic acid in phenylketonuria. A modification of the method applicable to histidinaemia was devised.

Simple paper chromatography of urine obtained in the Figlu test has been found satisfactory for determining excess excretion of the imidazole metabolites of histidine. It has been confirmed that examination for these in addition to formiminoglutamic acid is necessary for a full assessment of this test. When excretion of the latter is not abnormal in folic-acid and/or vitamin B(12) deficiency, that of urocanic acid, a glycine conjugate of urocanic acid and/or imidazole propionic acid, is usually raised. An abnormally high excretion of hydantoin-5-propionic acid after histidine has also been found in these deficiencies, and its estimation may be of additional use in the evaluation of the Figlu test.

A method for the determination of urinary normetadrenaline and metadrenaline is described whereby these 3-O-methoxy metabolites of noradrenaline and adrenaline are separated by paper chromatography before estimation by Pisano's method. Results in 80 normal subjects are given.

Filter paper blood samples were used to measure complement-fixation antibody in 34 children with sore throats. The method was satisfactory and should be particularly useful to minimize trauma in general practice and to conserve reagents in developing countries. [ABSTRACT FROM PUBLISHER]