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Microbiology and Immunology Oct 2019Loop-mediated isothermal amplification (LAMP) assays are used to detect diverse pathogens. Initially, LAMP amplicons were detected using electrophoresis; later,... (Review)
Review
Loop-mediated isothermal amplification (LAMP) assays are used to detect diverse pathogens. Initially, LAMP amplicons were detected using electrophoresis; later, real-time monitoring based on turbidity was developed to overcome the problem of contamination with environmental DNA. Recently, real-time monitoring of fluorescence signals using a quenching primer and probe has improved the reliability of amplification signals. Here, methods of detecting LAMP amplicons are reviewed.
Topics: Bacterial Infections; DNA, Bacterial; DNA, Protozoan; DNA, Viral; Fluorescence; Nephelometry and Turbidimetry; Nucleic Acid Amplification Techniques; Protozoan Infections; Reproducibility of Results; Virus Diseases
PubMed: 31342547
DOI: 10.1111/1348-0421.12734 -
Annales de Biologie Clinique Dec 2018The quantification of urine albumin is a common practice in Medical Biology laboratories. It allows the assessment of renal injury in common pathologies and many studies...
The quantification of urine albumin is a common practice in Medical Biology laboratories. It allows the assessment of renal injury in common pathologies and many studies have confirmed its role in the diagnosis and prognosis of these disorders. The physicochemical characteristics of albumin in the urine, very different from those in the blood, do not allow the use of the same standardized assay techniques for the blood albumin determination and make it difficult its quantification. Indeed, because of a physiological fragmentation phenomenon, urinary albumin is present in the urine as various small specific peptides. We will present here the main methods of determination of albumin in the urine, which are immuno-turbidimetric and immuno-nephelometric methods, high performance liquid chromatography with steric exclusion and liquid chromatography coupled with mass spectrometry. Currently, immunoanalysis techniques are the most used and are not standardized; large bias can be found between the different kits. This observation calls for a standardization of its determination in the urine.
Topics: Albuminuria; Chromatography, High Pressure Liquid; Chromatography, Liquid; Humans; Immunoassay; Nephelometry and Turbidimetry; Reference Standards; Serum Albumin; Tandem Mass Spectrometry; Urinalysis; Urine Specimen Collection
PubMed: 30543187
DOI: 10.1684/abc.2018.1390 -
Applied and Environmental Microbiology Sep 1980We describe an instrument for monitoring either transmitted or scattered light intensity, or both, simultaneously on up to eight channels. The use of a laser light...
We describe an instrument for monitoring either transmitted or scattered light intensity, or both, simultaneously on up to eight channels. The use of a laser light source (at 632.8-nm wavelength) provides high accuracy and dynamic range: optical density can be measured from 0.0004 up to 6, and a scattered light fraction down to 10(-6) can be resolved. Built-in thermostat and magnetic stirrers allow precise monitoring of aqueous microbial growth over a practical range of 4 orders of magnitude of cell concentration.
Topics: Escherichia coli; Lasers; Nephelometry and Turbidimetry; Penicillin G; Saccharomyces cerevisiae; Scattering, Radiation
PubMed: 6999988
DOI: 10.1128/aem.40.3.458-461.1980 -
Optics Express Nov 2008We report a novel light microscopy method for high resolution molecular imaging of thick biological tissues with one photon excited fluorescence. Effective optical...
We report a novel light microscopy method for high resolution molecular imaging of thick biological tissues with one photon excited fluorescence. Effective optical sectioning and diffraction limited spatial resolution are achieved when imaging deep inside a multiple-scattering medium by the use of focal modulation, a technique for suppressing the background fluorescence signal excited by scattered light. Our method has been validated with animal tissue and an imaging depth around 600 microns has been demonstrated.
Topics: Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Fiber Optic Technology; Image Enhancement; Microscopy, Confocal; Microscopy, Fluorescence; Nephelometry and Turbidimetry; Reproducibility of Results; Sensitivity and Specificity
PubMed: 19581963
DOI: 10.1364/oe.16.018764 -
Optics Express Nov 2011We measure the spectrum of coherent Brillouin scattering (CBS) in a gas as a function of time and observe for the first time additional spectral sidebands and line shape...
We measure the spectrum of coherent Brillouin scattering (CBS) in a gas as a function of time and observe for the first time additional spectral sidebands and line shape narrowing of the Brillouin peak. We find that both effects result from the interference of the density modulation induced by the moving dipole force of the pump beams with the acoustic waves induced by their fast thermalization and are predicted by a hydrodynamic-light scattering model. These line shapes differ from both spontaneous and stimulated Brillouin scattering spectra and also from previous coherent Rayleigh-Brillouin measurements.
Topics: Computer Simulation; Gases; Light; Models, Chemical; Nephelometry and Turbidimetry; Refractometry; Scattering, Radiation
PubMed: 22109429
DOI: 10.1364/OE.19.024046 -
Sensors (Basel, Switzerland) Apr 2014Turbidity is an internationally recognized criterion for assessing drinking water quality, because the colloidal particles in turbid water may harbor pathogens,...
Turbidity is an internationally recognized criterion for assessing drinking water quality, because the colloidal particles in turbid water may harbor pathogens, chemically reduce oxidizing disinfectants, and hinder attempts to disinfect water with ultraviolet radiation. A turbidimeter is an electronic/optical instrument that assesses turbidity by measuring the scattering of light passing through a water sample containing such colloidal particles. Commercial turbidimeters cost hundreds or thousands of dollars, putting them beyond the reach of low-resource communities around the world. An affordable open-source turbidimeter based on a single light-to-frequency sensor was designed and constructed, and evaluated against a portable commercial turbidimeter. The final product, which builds on extensive published research, is intended to catalyze further developments in affordable water and sanitation monitoring.
Topics: Calibration; Equipment Design; Nephelometry and Turbidimetry; Reference Standards
PubMed: 24759114
DOI: 10.3390/s140407142 -
The Journal of Physiology Nov 2005
Topics: Animals; Blood Platelets; Cell Count; History, 20th Century; Humans; Nephelometry and Turbidimetry; Photometry; Platelet Aggregation; United Kingdom
PubMed: 16123102
DOI: 10.1113/jphysiol.2005.095778 -
Journal of Biomedical Optics May 2015Light reflectance and transmission from soft tissue has been utilized in noninvasive clinical measurement devices such as the photoplethysmograph (PPG) and reflectance...
Light reflectance and transmission from soft tissue has been utilized in noninvasive clinical measurement devices such as the photoplethysmograph (PPG) and reflectance pulse oximeter. Incident light on the skin travels into the underlying layers and is in part reflected back to the surface, in part transferred and in part absorbed. Most methods of near infrared (NIR) spectroscopy focus on the volume reflectance from a semi-infinite sample, while very few measure transmission. We have previously shown that examining the full scattering profile (angular distribution of exiting photons) provides more comprehensive information when measuring from a cylindrical tissue. Furthermore, an isobaric point was found which is not dependent on changes in the reduced scattering coefficient. The angle corresponding to this isobaric point depends on the tissue diameter. We investigated the role of multiple scattering and absorption on the full scattering profile of a cylindrical tissue. First, we define the range in which multiple scattering occurs for different tissue diameters. Next, we examine the role of the absorption coefficient in the attenuation of the full scattering profile. We demonstrate that the absorption linearly influences the intensity at each angle of the full scattering profile and, more importantly, the absorption does not change the position of the isobaric point. The findings of this work demonstrate a realistic model for optical tissue measurements such as NIR spectroscopy, PPG, and pulse oximetery.
Topics: Absorption, Radiation; Animals; Computer Simulation; Humans; Light; Models, Biological; Nephelometry and Turbidimetry; Radiation Dosage; Refractometry; Scattering, Radiation
PubMed: 26016448
DOI: 10.1117/1.JBO.20.5.056010 -
American Journal of Hematology Apr 2008Under normal conditions, reticulocytes are the youngest erythrocytes released from the bone marrow into circulating blood. They mature for 1-3 days within the bone...
Under normal conditions, reticulocytes are the youngest erythrocytes released from the bone marrow into circulating blood. They mature for 1-3 days within the bone marrow and circulate for 1-2 days before becoming mature erythrocytes. Measurement of cellular hemoglobin concentration has long been reported by automated hematology analyzers as one of the red blood cell indices. The reticulocyte hemoglobin content (CHr or Ret-He) provides an indirect measure of the functional iron available for new red blood cell production over the previous 3-4 days. Measurement of reticulocyte hemoglobin content in peripheral blood samples is useful for diagnosis of iron deficiency in adults (Mast et al., Blood 2002;99:1489-1491) and children (Brugnara et al., JAMA 1999;281:2225-2230; Ullrich et al., JAMA 2005;294:924-930; Bakr and Sarette, Eur J Pediatr 2006;165:442-445). It provides an early measure of the response to iron therapy increasing within 2-4 days of the initiation of intravenous iron therapy (Brugnara et al., Blood 1994;83:3100-3101). Sequential measurements of reticulocyte hemoglobin content in patients with iron deficiency anemia provide a rapid means for assessing the erythropoietic response to iron replacement therapy (Brugnara et al., Blood 1994;83:3100-3101). It is also an early indicator or iron-restricted erythropoiesis in patients receiving erythropoietin therapy (Fishbane et al., Kidney Int 1997;52:217-222; Fishbane et al., Kidney Int 2001;60:2406-2411; Mittman et al., Am J Kidney Dis 1997;30:912-922; Tsuchiya et al., Clin Nephrol 2003;59:115-123; Chuang et al., Nephrol Dial Transplant 2003;18:370-377). Thus, reticulocyte hemoglobin content is a recent addition to an expanding list of biomarkers that can be used to differentiate iron deficiency from other causes of anemia.
Topics: Adult; Anemia; Anemia, Iron-Deficiency; Biomarkers; Diagnosis, Differential; Erythropoiesis; Erythropoietin; Hemoglobinometry; Humans; Iron; Nephelometry and Turbidimetry; Reticulocytes; Sensitivity and Specificity
PubMed: 18027835
DOI: 10.1002/ajh.21090 -
Journal of Clinical Laboratory Analysis May 2014SPAPLUS™ is a turbidimetric immunoassay analyzer for detection of excess free light chain (FLC) antigens in serum. Here, we evaluated the analytical performance of... (Comparative Study)
Comparative Study
BACKGROUND
SPAPLUS™ is a turbidimetric immunoassay analyzer for detection of excess free light chain (FLC) antigens in serum. Here, we evaluated the analytical performance of Freelite™ Human Kappa Free and Lambda Free on a SPAPLUS™ instrument.
METHODS
We evaluated the precision, linearity, sample carryover, and drift of the SPAPLUS™ instrument and compared it with Hitachi 7600 and BN™ II instruments. We evaluated the detection of antigen excess for 12 specimens from patients with monoclonal gammopathy.
RESULTS
The coefficients of variations of κFLC and λFLC were below 5.0%. Linearity was shown in the range of 9.68-152.25 mg/l for κFLC and 4.96-171.09 mg/l for λFLC, and no drift was observed. The κFLC sample carryover was statistically significant, but much smaller than the optimum allowable bias. Agreement rates with the two comparative methods were 87.1, 87.1, and 97.1% or higher for κFLC, λFLC, and the κ/λ ratio, respectively. Antigen excess signals were observed for all 12 antigen excess specimens.
CONCLUSIONS
The Freelite™ on the SPAPLUS™ exhibited appropriate precision, linearity, and relative comparability to the reagents on the other instruments. It was good at detecting specimens that had previously demonstrated the hook effect due to antigen excess.
Topics: Humans; Immunoassay; Immunoglobulin Light Chains; Nephelometry and Turbidimetry; Paraproteinemias; Sensitivity and Specificity
PubMed: 24478145
DOI: 10.1002/jcla.21671