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Biomedical subjects

D Hughes

Publications and source records attributed to D Hughes.

390 records · Page 22Linked to original sources
PubMedDate not supplied

Stimulation of the vestibular receptor by means of step temperature changes during continuous aural irrigation.

A technique for rapid, balanced hot/cold stimulation of the vestibular receptor is presented. During continuous aural irrigation the temperature of the irrigation fluid is switched between hot and cold values at times computed according to a mathematical model of heat conduction in the labyrinth area. As a result, the induced temperature difference across the lateral semicircular canal describes an approximately sinusoidal time course, reaching peak values of equal magnitude but opposite sign. Application of the test to 32 clinical subjects demonstrated that the heat conduction model and the analysis used in timing the sequence of thermal pulses was accurate. We expect that, with further refinements, the new technique will prove superior to conventional caloric test methods in the detection and measurement of subtle as well as gross abnormalities of the vestibular system.

Adult↗
PubMedDate not supplied

Salmonella in foods--a new enrichment procedure for use with the TECRA Salmonella visual immunoassay: collaborative study.

A collaborative study was conducted to compare a new enrichment procedure for the TECRA Salmonella Visual Immunoassay with the reference method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM 7th Ed.). Three food types (milk powder, black pepper, and soy flour) were analyzed in Australia, and 3 food types (milk chocolate, dried egg, and raw turkey) were analyzed in the United States. Thirty-eight collaborators participated in the study. No significant differences (p > 0.05) were observed for the pairwise comparison of the proportion of positive samples for the TECRA method with that for the reference method. The new enrichment procedure for the TECRA method has been adopted First Action by AOAC INTERNATIONAL.

Animals↗
PubMedDate not supplied

An immunoassay method for rapid detection of Staphylococcus aureus in cosmetics, pharmaceutical products, and raw materials.

The TECRA Staphylococcus aureus Visual Immunoassay allows a presumptive positive or negative result for the presence of S. aureus to be obtained within 26 h, in contrast to 4-5 days by traditional cultural methods. Presumptive positive immunoassay results are confirmed by streaking the enrichment broth onto conventional agar media. A validation study was undertaken to compare the TECRA assay with a cultural reference method based on the Bacteriological Analytical Manual (8th Ed.), which is also consistent with U.S. Pharmacopoeia requirements. The products tested included a range of cosmetics (toothpaste, shampoos, conditioners, sunscreens, moisturizers, lip and eye creams) and pharmaceuticals (cough mixtures, laxatives, ulcer treatments, infant formulae, antiseptic cream), as well as some pharmaceutical ingredients. Samples were inoculated with S. aureus at 10-20 cfu/g, and then enriched for 24 h at 35 degrees-37 degrees C at a product-to-sample ratio of 1:100. Two different enrichment broths were used for the study: Tryptone Soya Broth with 4% Tween 80 and Modified Letheen Broth. For both enrichment broths, results of the immunoassay and the reference method showed close correlation. The TECRA S. aureus Visual Immunoassay provides a rapid and convenient alternative to cultural methods and provides advantages to industry, such as greater speed of product and ingredient release and faster tracing of contamination problems. Because the immunoassay may be read either visually or with the aid of a plate reader, there is no need for an initial outlay on capital equipment. However, the assay can be automated if required.

Bacteriological Techniques↗
PubMedDate not supplied

TECRA Unique test for rapid detection of Salmonella in food: collaborative study.

The TECRA Unique Salmonella test uses the principle of immunoenrichment to allow rapid detection of Salmonellae in food. A collaborative study was conducted to compare the TECRA Salmonella Unique test with the reference culture method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual. Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 2 food types (milk chocolate and dried egg) were analyzed in the United States. Forty-one collaborators participated in the study. For each of the 5 foods at each of the 3 levels, a comparison showed no significant differences (p > or = 0.05) in the proportion of positive test samples for Unique and that for the reference method using the Chi-square test for independence with continuity correction.

Antibodies, Bacterial↗
PubMedDate not supplied

TECRA Listeria Visual Immunoassay (TLVIA) for detection of Listeria in foods: collaborative study.

A collaborative study involving 26 laboratories and 5 food types was performed to compare the TECRA Listeria Visual Immunoassay (TLVIA) with standard culture methods. Three foods (lettuce, ice cream, and fish fillets), under the jurisdiction of the U.S. Food and Drug Administration, and 2 foods (cooked chicken and cooked ground turkey), under the jurisdiction of the U.S. Department of Agriculture, were used to determine the effectiveness of the TLVIA. Of the 900 samples tested, 300 were inoculated with low levels (1-5 cells/25 g) of Listeria spp. and 300 were inoculated with high levels of Listeria spp. (10-50 cells/25 g). Method agreement between the conventional culture methods and TLVIA (visual) was 94.7%. Method agreement between the conventional culture methods and TLVIA (reader) was 93.6%. The colorimetric polyclonal enzyme immunoassay (TLVIA) for detection of Listeria in foods has been adopted first action by AOAC INTERNATIONAL.

Animals↗
PubMedDate not supplied

Comparison of modified TECRA visual immunoassay with AOAC method 989.14 and reference culture methods 967.25-967.28 for detection of Salmonella in foods and related samples.

A validation study was conducted to compare a new modified version of the TECRA Salmonella Visual immunoassay (Mod. VIA) with the original immunoassay (AOAC Method 989.14) and the reference culture methods (967.25-967.28). The Mod. VIA was supplemented with polyclonal antibodies to Salmonella pullorum and S. gallinarum, and compared favorably with AOAC Method 989.14 in sensitivity, inclusivity, and exclusivity studies. The ability of the Mod. VIA to recover Salmonella from artificially contaminated samples was not significantly different from that of the reference method. It is recommended that the Mod. VIA be adopted as Official First Action.

Culture Media↗