Browsing by Subject "Blood Chemical Analysis"

Now showing 1 - 5 of 5
  • No Thumbnail Available
    ItemOpen Access
    Analytical performance evaluation of the Elecsys® Troponin T Gen 5 STAT assay.
    (Clinica chimica acta; international journal of clinical chemistry, 2019-08) Fitzgerald, Robert L; Hollander, Judd E; Peacock, W Frank; Limkakeng, Alexander T; Breitenbeck, Nancy; Blechschmidt, Kareen; Laimighofer, Michael; deFilippi, Christopher
    BACKGROUND:We report the analytical performance of the Elecsys® Troponin T Gen 5 STAT (TnT Gen 5 STAT; Roche Diagnostics) assay. METHODS:Measuring limits/ranges were determined in lithium-heparin plasma samples per Clinical and Laboratory Standards Institute (CLSI) EP17-A2. Precision was evaluated per CLSI EP05-A2 using lithium-heparin plasma/quality control samples on cobas e 411/cobas e 601 analyzers; two duplicated runs per day for 21 days (n = 84). Cross-reactivity with other troponin forms and interference from endogenous substances/drugs was tested; recovery criterion for no cross-reactivity was within ±10%. RESULTS:Coefficients of variation (CV) for repeatability/intermediate precision were 0.7-5.6%/1.4-10.3% (cobas e 411; mean cardiac troponin T [cTnT]: 7.3-9341 ng/L) and 0.7-3.0%/1.5-6.4% (cobas e 601; mean cTnT: 7.4-9455 ng/L). There was no cross-reactivity with skeletal muscle troponin T (≤ 10,000 ng/L), skeletal muscle troponin I (≤ 100,000 ng/L), cardiac troponin I (≤ 10,000 ng/L), or human troponin C (≤ 80,000 ng/L). No interference was observed with biotin (≤ 20 ng/mL) or 34 drugs. CONCLUSION:The TnT Gen 5 STAT assay demonstrated a CV of <10% at the 99th percentile upper reference limit, meeting precision requirements (Fourth Universal Definition of Myocardial Infarction) for high-sensitivity troponin assays.
  • Thumbnail Image
    ItemOpen Access
    Design of protease-resistant peptide ligands for the purification of antibodies from human plasma.
    (Journal of chromatography. A, 2016-05) Menegatti, Stefano; Bobay, Benjamin G; Ward, Kevin L; Islam, Tuhidul; Kish, William S; Naik, Amith D; Carbonell, Ruben G
    A strategy is presented for developing variants of peptide ligands with enhanced biochemical stability for the purification of antibodies from animal sera. Antibody-binding sequences HWRGWV, HYFKFD, and HFRRHL, previously discovered by our group, were modified with non-natural amino acids to gain resistance to proteolysis, while maintaining target affinity and selectivity. As trypsin and α-chymotrypsin were chosen as models of natural proteolytic enzymes, the basic (arginine and lysine) and aromatic (tryptophan, phenylalanine, and tyrosine) amino acids were replaced with non-natural analogs. Using the docking software HADDOCK, a virtual library of peptide variants was designed and screened in-silico against the known HWRGWV binding site on the pFc fragment of IgG. A pool of selected sequences with the highest predicted free energy of binding was synthesized on chromatographic resin, and the resulting adsorbents were tested for IgG binding and resistance to proteases. The ligand variants exhibited binding capacities and specificities comparable to the original sequences, yet with much higher proteolytic resistances. The sequences HWMetCitGWMetV and HFMetCitCitHL was used for purifying polyclonal IgG from IgG-rich fractions of human plasma, with yields and purity above 90%. Notably, due to electrical neutrality, the variant showed higher selectivity than the original sequence. Binding isotherms were also constructed, which confirmed the docking predictions. This method represents a general strategy for enhancing the biochemical stability as well as the affinity and selectivity of natural or synthetic peptide ligands for bioseparations.
  • Thumbnail Image
    ItemOpen Access
    Hematology and serum biochemistry of free-ranging mantled howler monkeys (Alouatta palliata) at La Pacifica, Costa Rica.
    (Journal of medical primatology, 2024-08) Larsen, R Scott; Moresco, Anneke; Meneses, Ana; Glander, Kenneth E

    Background

    Hematologic and blood biochemical values are key tools for assessing primate health. A long-term behavioral study of howler monkeys at a single site (La Pacífica, Guanacaste, Costa Rica), afforded the opportunity to develop baseline values for a large group of animals, evaluating differences between adult males and females and comparing to a report in the same population two decades later.

    Methods

    In 1998, 64 free-ranging mantled howler monkeys were anesthetized and sampled for hematologic and biochemical analysis.

    Results

    Blood analysis is reported for 29 adult females, 9 juvenile females, 19 adult males and 3 juvenile males. Four adults were excluded due to external injury or disease. There were few significant differences between adult females, juvenile females, and adult males.

    Conclusions

    Baseline blood parameters are useful for determining normal values for howler monkey populations. The values for total protein, blood urea nitrogen, glucose, liver enzymes and potassium differed from a later study in 2019 may indicate changes that are influencing howler monkey health.
  • Thumbnail Image
    ItemOpen Access
    Irisin - a myth rather than an exercise-inducible myokine.
    (Sci Rep, 2015-03-09) Albrecht, E; Norheim, F; Thiede, B; Holen, T; Ohashi, T; Schering, L; Lee, S; Brenmoehl, J; Thomas, S; Drevon, CA; Erickson, HP; Maak, S
    The myokine irisin is supposed to be cleaved from a transmembrane precursor, FNDC5 (fibronectin type III domain containing 5), and to mediate beneficial effects of exercise on human metabolism. However, evidence for irisin circulating in blood is largely based on commercial ELISA kits which are based on polyclonal antibodies (pAbs) not previously tested for cross-reacting serum proteins. We have analyzed four commercial pAbs by Western blotting, which revealed prominent cross-reactivity with non-specific proteins in human and animal sera. Using recombinant glycosylated and non-glycosylated irisin as positive controls, we found no immune-reactive bands of the expected size in any biological samples. A FNDC5 signature was identified at ~20 kDa by mass spectrometry in human serum but was not detected by the commercial pAbs tested. Our results call into question all previous data obtained with commercial ELISA kits for irisin, and provide evidence against a physiological role for irisin in humans and other species.
  • Thumbnail Image
    ItemOpen Access
    Noninvasive monitoring of tissue hemoglobin using UV-VIS diffuse reflectance spectroscopy: a pilot study.
    (Opt Express, 2009-12-21) Bender, Janelle E; Shang, Allan B; Moretti, Eugene W; Yu, Bing; Richards, Lisa M; Ramanujam, Nirmala
    We conducted a pilot study on 10 patients undergoing general surgery to test the feasibility of diffuse reflectance spectroscopy in the visible wavelength range as a noninvasive monitoring tool for blood loss during surgery. Ratios of raw diffuse reflectance at wavelength pairs were tested as a first-pass for estimating hemoglobin concentration. Ratios can be calculated easily and rapidly with limited post-processing, and so this can be considered a near real-time monitoring device. We found the best hemoglobin correlations were when ratios at isosbestic points of oxy- and deoxyhemoglobin were used, specifically 529/500 nm. Baseline subtraction improved correlations, specifically at 520/509 nm. These results demonstrate proof-of-concept for the ability of this noninvasive device to monitor hemoglobin concentration changes due to surgical blood loss. The 529/500 nm ratio also appears to account for variations in probe pressure, as determined from measurements on two volunteers.