PubMed · 7167518
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B Audone, L Bolla, G Gerbi, P Gabriele. 1982. E- and H-field sensor system.. https://pubmed.ncbi.nlm.nih.gov/7167518/
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Two modified GC-based isotope ratio MS (IRMS) techniques, for measurement of [13C]leucine enrichment in muscle protein, were compared with a conventional dual inlet technique. Of these three, two involved HPLC purification of leucine and liberation of carbon dioxide (CO2) using the ninhydrin reaction. In the conventional technique the CO2 was introduced into the MS by a dual inlet system following cryogenic concentration. In the second method (ninhydrin/GC/IRMS) the CO2 was purified by on-line GC. In the third technique, GC/combustion/IRMS, derivatized amino acids are separated by GC and analyzed after combustion. A primed continuous infusion of L-[1-13C]leucine was given intravenously to human subjects and needle quadriceps muscle biopsies were taken to measure [13C]leucine enrichment in muscle protein. All three methods demonstrated excellent correlation (r > 0. 999). Differences in the measurement of [13C]leucine enrichment in muscle protein were <6%. The ninhydrin techniques require microgram quantities of leucine, with the conventional technique requiring twice the amount as the ninhydrin/GC/IRMS method. The GC/combustion/IRMS technique requires only nanogram quantities of leucine with similar precision enabling measurement of synthesis rates of individual proteins from biopsy samples. We have measured the isotopic enrichment of myosin heavy chain and mixed muscle protein in human subjects using the GC/combustion/IRMS technique.
A partial least-squares calibration (PLS) method for the simultaneous spectrofluorimetric determination of acetylsalicylic acid, codeine and ephedrine is proposed. The use of PLS for the multicomponent spectrofluorimetric determination is demonstrated by analysing synthetic mixtures. Analyte mixtures can be resolved even in the presence of strongly overlapped fluorescence signals. The method was validated by subjecting experimental data to exhaustive statistical analysis. The proposed method was applied to the simultaneous determination of the three drugs in synthetic mixtures with a urine matrix. The concentration ranges considered are 1.56-10.92 and 25-100 micrograms/ml for the codeine-ephedrine mixture, and 0.8-3.2, 0.1-0.5 and 1.6-4.8 micrograms/ml for the acetylsalicylic acid-codeine-ephedrine mixture. The analytical results were quite good in all cases.
In comparative genomic hybridization (CGH), quantitative measurement of fluorescence intensity ratios on metaphase chromosomes is the basic method for detecting copy number changes in the test DNA. The microscope images are usually acquired by high-resolution, highly sensitive, black and white (B&W) CCD cameras. This requires subsequent recording of the different color images using appropriate filter combinations for excitation and emission. We describe an alternative approach using the one-chip true-color CCD camera Kappa CF 15 MC and an Omega triple-bandpass filter for simultaneous registration of the three dyes Texas red, FTTC, and DAPI. A detailed examination of the imaging properties of the system was performed. The camera response in the three color planes R, G, and B was evaluated, and calibration factors for image correction were calculated. An error estimate is given. A complete computer program for the image analysis of CGH experiments has been developed for an 80486 PC, using the commercially available software package Optimas as the basis for image recording. Examples that confirm the suitability of the system for ratio imaging in CGH are presented. The results were compared with others obtained from the same microscope slides using an established setup consisting of a B&W CCD camera (Photometrics) and a software program based on the TCL software package and run on a Macintosh Quadra 950. The results obtained using the two different systems were found to correspond closely.