PubMed · 14167498
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T MOTEKI. 1964. [AUTOANALYZER].. https://pubmed.ncbi.nlm.nih.gov/14167498/
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UNLABELLED: The literature about salivary lactate dehydrogenase (LDH) activity shows different results, conditioned by the diversity of methods used for sampling, handling and analysis. OBJECTIVES: The aim of this study was to design a protocol for quantifying salivary lactate dehydrogenase activity. METHODS: Whole saliva samples were collected from 100 healthy volunteers by chewing a roll of cotton. Lactate dehydrogenase activity determinations were made with the Cobas Mira Plus II autoanalyser using the recommendations proposed by the International Federation of Clinical Chemistry (IFCC) and the French Society of Clinical Biology (SFBC). Samples were stored at room temperature (20-22 degrees C), in the refrigerator (4 degrees C) and freezer (-20 degrees C). The correction capacity of the autoanalyser was evaluated by making serial determinations in samples of saliva diluted in water. RESULTS: The frozen samples, but not those stored in the refrigerator or at room temperature, showed an important degradation of lactate dehydrogenase activity. When the samples were diluted in water, the lactate dehydrogenase activity varied substantially with the International Federation of Clinical Chemistry method after correction, but not when using the French Society of Clinical Biology method. CONCLUSION: For salivary lactate dehydrogenase activity quantification we suggest that samples be stored at 4 degrees C and analyse with the French Society of Clinical Biology method.
Analysis of biogenic volatile organic compounds (BVOC) of 14 Eucalyptus clones has been performed using an automated headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography (GC)/ion trap mass spectrometry (ITMS) method. Correlations between pulp properties of Eucalyptus clones and the BVOC of their leaf headspaces were studied. The compounds alpha-terpineol and the sesquiterpene beta-eudesmol were positively correlated with S5, a property related to the hemicelluose content in the pulp. Qualitative results obtained with automated HS-SPME were sufficient to group together the same species and related hybrids through cluster analysis and were confirmed through principal component analysis. A preliminary separation of the essential oils of Eucalyptus dunnii through comprehensive two-dimensional gas chromatography (GC x GC) showed approximately 580 peaks compared to approximately 60 in a typical GC/ITMS first-dimension chromatogram. The potential of HS-SPME coupled to GC x GC to improve the separation of Eucalyptus volatiles and other plant essential oils looks extremely promising for new applications of unsupervised learning methods.
BACKGROUND: Scanning for mutations in BRCA1 and BRCA2 in a large number of samples is hampered by the large sizes of these genes and the scattering of mutations throughout their coding sequences. Automated capillary electrophoresis has been shown to be a powerful system to detect mutations by either single-strand conformation polymorphism or heteroduplex analysis (HA). METHODS: We investigated the adaptation of gel-based HA of BRCA1 and BRCA2 to a fluorescent multicapillary platform to increase the throughput of this technique. We combined multiplex PCR, three different fluorescent labels, and HA in a 16-capillary DNA sequencer and tested 57 DNA sequence variants (11 insertions/deletions and 46 single-nucleotide changes) of BRCA1 and BRCA2. RESULTS: We detected all 57 DNA changes in a blinded assay, and 2 additional single-nucleotide substitutions (1186 A>G of BRCA1 and 3624 A>G of BRCA2), previously unresolved by conformation-sensitive gel electrophoresis. Furthermore, different DNA changes in the same PCR fragment could be distinguished by their peak patterns. CONCLUSIONS: Capillary-based HA is a fast, efficient, and sensitive method that considerably reduces the amount of "hands-on" time for each sample. By this approach, the entire coding regions of BRCA1 and BRCA2 from two breast cancer patients can be scanned in a single run of 90 min.