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At least 307 records · Page 17Linked to original sources
PubMed1979

Manual and continuous-flow colorimetry of triacylglycerols by a fully enzymic method.

We describe a fully enzymic method for manual and continuous-flow colorimetric assay of triacylglycerols (triglycerides) in serum. Triglycerides are enzymically hydrolyzed in 10 min by lipase and microbial esterase. The resulting free glycerol is measured enzymically by glycerol kinase and glycerol-3-phosphate dehydrogenase. The NADH so formed is oxidized by coupling with a tetrazolium salt/diaphorase system. The test follows Beer's law to 8 g/L, and the final color is stable for at least 1 h for serum, 15 min for aqueous triolein standards. The manual assay requires only 25 microliter of serum and few manipulations. A specific triolein standard was developed for calibrating the manual method. For the continuous-flow method, calibration is made with four concentrations of glycerol standard. The procedure is sensitive, has good precision and accuracy, and gives results that compare well with chemical and enzymic commercial kit methods.

Adult↗
PubMedDate not supplied

Enumeration of total bacteria in raw and pasteurized milk by reflectance colorimetry: collaborative study.

Seven out of 9 laboratories completed a collaborative study comparing a reflectance colorimetric (RC) bioactivity monitor (Omnispec 4000) method to the standard plate count (SPC) method for estimation of total bacteria in raw and homogenized pasteurized milk. Each laboratory analyzed 12 different samples by the SPC method and 24 samples (12 blind duplicates) by the RC method. For the RC method RSDr was 1.7%, and RSDR was 4.5%. RSDR for the SPC method was 20.8%. The method was adopted first action by AOAC INTERNATIONAL.

Animals↗
PubMed1977

Improved colorimetry of urinary 3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid).

Homovanillic acid is an important metabolite of dopamine, and a high proportion of patients with neuroblastoma excrete increased amounts of it in their urine. When this diagnosis is suspected, both homovanillic acid and vanilmandelic acid should be measured, because such a combined measurement reportedly leads to detection of 95% of cases. Although rapid and reliable chemical methods are available for vanilmandelic acid, the same is not true for homovanillic acid. We report here a colorimetric method for homovanillic acid that reasonably fills this void and that can be used in most clinical laboratories. In addition, we present normal values determined for children of various age groups.

Adolescent↗
PubMed1998

[Lymphoblast transformation colorimetry in the diagnosis of drug hypersensitivity].

Diagnosis of drug allergy has been considered to be a multistage procedure consisting of detailed history of previous medication, analysis of symptoms, laboratory tests and provocation with the supposed sensitizing drug. Many laboratory methods are used for demonstration drug allergy, but opinions differ with regard to their specificity, sensitivity and reproducibility. Lymphocyte transformation test (LTT) is considered to be a valuable in vitro method in the diagnosis of drug allergy. For evaluation of LTT we introduced a tetrazolium-based colorimetric assay (MTT). Comparison of MTT assay with 3H-Thymidine incorporation in evaluation of Phytohaemagglutinin induced LTT resulted no significant difference in the dose-response curve. During the past 3 years 315 patients were tested with LTT-MTT method; 736 lymphocyte transformation tests mainly with antibiotics, topical anesthetics and painkillers were evaluated by MTT resulting 280 positive results. Physicians requested skin tests were performed with drugs induced no in vitro lymphocyte transformation and only 8 topical reactions without general symptoms were observed. MTT method was found to be a sensitive laboratory test in evaluation of LTT performable even in routine laboratories. Its application can lead to a substantial decrease in the number of patients who must be subjected to the possible risk of in vivo tests for the determination of the sensitizing drug.

Colorimetry↗
PubMed1978

Colorimetry by a new principle.

A simple and informative method is described for determining the type and extent of color defects. The subjects' responses are registered automatically on a chromaticity diagram that is based on the newtonian model. Color defects are readily identifiable by a skewing of the normal central gray area toward the defectively perceived color. The examination permits independent variation of hue and saturation for each color and requires less than five minutes for the entire procedure. Unlike conventional color tests, the present method indicates exactly what colors are or are not seen at any level of saturation.

Adolescent↗
PubMed1978

Interobserver error in human skin colorimetry.

Twenty light-skinned adults were measured at the upper inner arm site using two commonly used reflectance spectrophotometers. Each subject was measured by each of three investigators to assess the influence of interobserver error on the reflectance readings. A repeated measures design analysis of variance showed no significant variance component due to observers.

Humans↗
PubMed1995

Comparison of reversed-phase liquid chromatography with colorimetry for analysis of phenolphthalein preparations.

The high-performance liquid chromatography (HPLC) method of the United States Pharmacopeia has been compared with the colorimetric method of the British Pharmacopoeia for the assay of phenolphthalein in various preparations. Results are presented for the linearity, sensitivity and reproducibility of the two methods. The HPLC method was considered to be more convenient for routine analysis of the preparations of phenolphthalein.

Calibration↗
PubMed2002

White spot syndrome virus and infectious hypodermal and hematopoietic necrosis virus simultaneous diagnosis by miniarray system with colorimetry detection.

Highly sensitive and specific diagnostic tools are essential for monitoring the health status of farmed species. After the development of genomic probe diagnostic systems in the 1990s, followed by PCR-based systems, a miniarray method has been developed allowing one-step multiple detection. The miniarray method was developed to enable the accessibility of powerful array technology. To use this system, hybridisation and washing process were modified, resulting into a significant increase in the test's rapidity and sensitivity. With miniarray technology, hybridisation time is reduced to 20 min, whereas other methods require a longer hybridisation time. Hybridisation of the PCR product on a nylon membrane and revelation of the hybrids by an antibody increase considerably the ability of pathogen's detection. A first application is developed for the diagnosis of two specific viruses which are, by their geographical range and their impact on the production, very important in shrimp pathology, namely, the White Spot Syndrome Virus (WSSV) and the Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV).

Animals↗
PubMed1968

Colorimetry.

Explore the source record for details and available documents.

California↗
PubMed2001

The detection of phytohemagglutinin-lymphokine activated killer cells' in vitro antitumor action with MTT colorimetry.

OBJECTIVE: To detect the in vitro antitumor action of phytohemagglutinin and lymphokine activated killer (PHA- LAK) cells. METHOD: MTT colorimetric assay was used to detect the in vitro cytotoxicity of PHA-LAK cells on K562 MGc80-3 143TK Hela and LoVo. RESULTS: The significant cytotoxicity of PHA-LAK cells on these five tumor cells from different organs could be found in vitro. The PHA-LAK cell activity on 143TK could reach 57.3% when the ratio of effective cell (EC) to target cell (TC) was 7.5:1. The antitumor effect did not increased or even decreased when the ratio of EC to TC was 15:1. CONCLUSIONS: (1)PHA-LAK cell has non-specific cytotoxicity against tumor cells and can overcome the problems of the quantity and activity of immunocyte of traditional adoptive cellular immunotherapy. (2)Under some conditions does MTT colorimetric assay be a susceptible, simple and convenient method for detecting the cytotoxicity of immunocytes.

Journal Article↗