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Applied and Environmental Microbiology Jan 2020Previous work has demonstrated that the physical properties of intracellular bacterial gas vesicles (GVs) can be analyzed using pressure nephelometry. In analyzing the...
Previous work has demonstrated that the physical properties of intracellular bacterial gas vesicles (GVs) can be analyzed using pressure nephelometry. In analyzing the buoyant state of GV-containing cyanobacteria, hydrostatic pressure within a sample cell is increased in a stepwise manner, where the concomitant collapse of GVs due to pressure and the resultant decrease in suspended cells are detected by changes in nephelometric scattering. As the relative pressure at which GVs collapse is a function of turgor pressure and cellular osmotic gradients, pressure nephelometry is a powerful tool for assaying changes in metabolism that affect turgor, such as photosynthetic and osmoregulatory processes. We have developed an updated and automated pressure nephelometer that utilizes visible-infrared (Vis-IR) spectra to accurately quantify GV critical collapse pressure, critical collapse pressure distribution, and cell turgor pressure. Here, using the updated pressure nephelometer and axenic cultures of PCC7806, we demonstrate that GV critical collapse pressure is stable during mid-exponential growth phase, introduce pressure-sensitive turbidity as a robust metric for the abundance of gas-vacuolate cyanobacteria, and demonstrate that pressure-sensitive turbidity is a more accurate proxy for abundance and growth than photopigment fluorescence. As cyanobacterium-dominated harmful algal bloom (cyanoHAB) formation is dependent on the constituent cells possessing gas vesicles, characterization of environmental cyanobacteria populations via pressure nephelometry is identified as an underutilized monitoring method. Applications of this instrument focus on physiological and ecological studies of cyanobacteria, for example, cyanoHAB dynamics and the drivers associated with cyanotoxin production in aquatic ecosystems. The increased prevalence of bloom-forming cyanobacteria and associated risk of exposure to cyanobacterial toxins through drinking water utilities and recreational waterways are growing public health concerns. Cost-effective, early-detection methodologies specific to cyanobacteria are crucial for mitigating these risks, with a gas vesicle-specific signal offering a number of benefits over photopigment fluorescence, including improved detection limits and discrimination against non-gas-vacuolate phototrophs. Here, we present a multiplexed instrument capable of quantifying the relative abundance of cyanobacteria based on the signal generated from the presence of intracellular gas vesicles specific to bloom-forming cyanobacteria. Additionally, as cell turgor can be measured via pressure nephelometry, the measurement furnishes information about the internal osmotic pressure of gas-vacuolate cyanobacteria, which relates to the metabolic state of the cell. Together these advances may improve routine waterway monitoring and the mitigation of human health threats due to cyanobacterial blooms.
Topics: Cyanobacteria; Harmful Algal Bloom; Microcystis; Nephelometry and Turbidimetry; Phytoplankton
PubMed: 31676479
DOI: 10.1128/AEM.01790-19 -
Analytical and Bioanalytical Chemistry May 2021Many patients develop coagulation abnormalities due to chronic and hereditary disorders, infectious disease, blood loss, extracorporeal circulation, and oral...
Many patients develop coagulation abnormalities due to chronic and hereditary disorders, infectious disease, blood loss, extracorporeal circulation, and oral anticoagulant misuse. These abnormalities lead to bleeding or thrombotic complications, the risk of which is assessed by coagulation analysis. Current coagulation tests pose safety concerns for neonates and small children due to large sample volume requirement and may be unreliable for patients with coagulopathy. This study introduces a containerless drop-of-blood method for coagulation analysis, termed "integrated quasi-static acoustic tweezing thromboelastometry" (i-QATT™), that addresses these needs. In i-QATT™, a single drop of blood is forced to levitate and deform by the acoustic radiation force. Coagulation-induced changes in drop turbidity and firmness are measured simultaneously at different instants. The parameters describing early, intermediate, and late stages of the coagulation process are evaluated from the resulting graphical outputs. i-QATT™ rapidly (<10 min) detected hyper- and hypo-coagulable states and identified single deficiency in coagulation factors VII, VIII, IX, X, and XIII. The linear relationship (r > 0.9) was established between fibrinogen concentration and two i-QATT™ parameters: maximum clot firmness and maximum fibrin level. Factor XIII activity was uniquely measured by the fibrin network formation time (r = 0.9). Reaction time, fibrin formation rate, and time to firm clot formation were linearly correlated with heparin concentration (r > 0.7). tPA-induced hyperfibrinolysis was detected in the clot firmness output at 10 min. i-QATT™ provides comprehensive coagulation analysis in point-of-care or laboratory settings, well suited to the needs of neonatal and pediatric patients and adult patients with anemia or blood collection issues.
Topics: Anticoagulants; Blood Coagulation; Drug Monitoring; Feasibility Studies; Humans; Nephelometry and Turbidimetry; Thrombelastography
PubMed: 33796930
DOI: 10.1007/s00216-021-03278-8 -
Sensors (Basel, Switzerland) Oct 2019Immunoassays have been widely used in scientific research and clinical diagnosis due to their versatile detection capability and high specificity. Immunoagglutination...
Immunoassays have been widely used in scientific research and clinical diagnosis due to their versatile detection capability and high specificity. Immunoagglutination assays are kinds of immunoassay, which can simply and rapidly measure the concentration of analytes. In this work, we developed a low-cost micro-volume nephelometric system for quantitative immunoagglutination assays. We used off-the-shelf components to build the system, and the total cost of key components is only about 20 US dollars. The total detection volume in our system was as low as 3 µL, which could significantly reduce the reagent cost and required sample volume. We further evaluated the system performance via the immunoagglutination assay to measure the concentration of C-reactive protein, a plasma protein with levels rising in response to inflammation. The results demonstrated that our system could measure the concentration of analytes with relatively high sensitivity and precision within four minutes, and has high potential to be applied for clinical diagnostic tests.
Topics: Agglutination Tests; C-Reactive Protein; Costs and Cost Analysis; Humans; Imaging, Three-Dimensional; Immunoassay; Nephelometry and Turbidimetry; Scattering, Radiation
PubMed: 31600932
DOI: 10.3390/s19204359 -
Bioanalysis Mar 2018There is no commercially available urinary cystatin-C (u-CYSC) test in the market. Therefore, we optimized and validated an automated immune turbidimetric test for...
AIM
There is no commercially available urinary cystatin-C (u-CYSC) test in the market. Therefore, we optimized and validated an automated immune turbidimetric test for u-CYSC measurements and investigated u-CYSC concentrations in acute and chronic diseases which might lead to renal tubular disorders.
MATERIALS & METHODS
A particle-enhanced immune turbidimetric assay was adapted and validated on a Cobas 8000/c502 analyzer. Urine samples of different patient groups were also analyzed.
RESULTS
Our method showed excellent analytical performance. U-CYSC/u-creatinine (u-CREAT) was higher in sepsis-related acute kidney injury group (p < 0.001) compared with controls and to patients with chronic hypertension and Type 2 diabetes.
CONCLUSION
We validated a fast, sensitive, fully automated u-CYSC assay which is ideal for routine use and might be a potential complementary laboratory test to evaluate renal tubular function.
Topics: Cystatin C; Humans; Nephelometry and Turbidimetry
PubMed: 29451000
DOI: 10.4155/bio-2017-0228 -
Pediatric Nephrology (Berlin, Germany) Feb 2020Cystatin C is a key GFR biomarker. Recently, Siemens recalibrated the assay based on certified reference material ERM-DA471/IFCC. The NIH-funded longitudinal chronic...
BACKGROUND
Cystatin C is a key GFR biomarker. Recently, Siemens recalibrated the assay based on certified reference material ERM-DA471/IFCC. The NIH-funded longitudinal chronic kidney disease in children (CKiD) study has > 3000 cystatin C measurements based on a pre-IFCC calibrator provided by Siemens. Since cystatin C values for CKiD are now standardized to IFCC certified reference material, it is important to relate the IFCC-calibrated results to the previous values so that there are no discontinuous results.
METHODS
We diluted cystatin C ERM-DA471/IFCC (5.48 mg/L) into buffer and compared results with predicted ones. We then updated the cystatin C application on our BN II nephelometer to provide results based on pre-IFCC and IFCC calibrations of CKiD specimens simultaneously. We assayed 51 previously analyzed sera and 62 fresh additional specimens.
RESULTS
The predicted concentrations from the IFCC standard were consistently 17% higher than the measured values using the pre-IFCC calibration (y = 1.1686x). Similarly, the re-run and fresh sample concentrations were 17% higher via the IFCC calibration than by the pre-IFCC calibration (y = 1.168x). There was very high reliability in the measurements using the previous calibration for re-run specimens (0.99) and for 33 pristine specimens using IFCC calibration (0.99).
CONCLUSIONS
We confirm the recalibration proposed by Siemens. To convert pre-IFCC results to IFCC-calibrated concentrations, the value is multiplied by 1.17. Conversely, one divides IFCC-calibrated results by 1.17 to estimate GFR via previously published pre-IFCC CKiD eGFR equations. For older adolescents, cystatin C has already been standardized and can be directly applied to the CKD-EPI equations.
Topics: Cystatin C; Humans; Nephelometry and Turbidimetry; Reference Values
PubMed: 31680199
DOI: 10.1007/s00467-019-04389-2 -
Applied and Environmental Microbiology Dec 1982An inexpensive, simple-to-construct nephelometer which was used to monitor the lysis of spheroplasts is described. The nephelometer is a flow-through device with a...
An inexpensive, simple-to-construct nephelometer which was used to monitor the lysis of spheroplasts is described. The nephelometer is a flow-through device with a linear response to cell concentration from the lower detection limit to 8 x 10(8) cells per ml.
Topics: Bacteriolysis; Nephelometry and Turbidimetry; Spheroplasts
PubMed: 7159090
DOI: 10.1128/aem.44.6.1476-1478.1982 -
Journal of Biomedical Optics Feb 2011Experiments were conducted to study polarized light transmission in fresh bovine skeletal muscle of varying thicknesses. Two-dimensional polarization-sensitive...
Experiments were conducted to study polarized light transmission in fresh bovine skeletal muscle of varying thicknesses. Two-dimensional polarization-sensitive transmission images were acquired and analyzed using a numerical parametric fitting algorithm. The total transmittance intensity and degree-of-polarization were calculated for both central ballistic and surrounding scattering regions. Full Mueller matrix images were derived from the raw polarization images and the polar decomposition algorithm was applied to extract polarization parameters. The results suggest that polarized light propagation through skeletal muscle is affected by strong birefringence, diattenuation, multiple scattering induced depolarization and the sarcomere diffraction effect.
Topics: Animals; Cattle; In Vitro Techniques; Light; Lighting; Muscle, Skeletal; Nephelometry and Turbidimetry; Refractometry; Scattering, Radiation
PubMed: 21361681
DOI: 10.1117/1.3536512 -
Microbiology and Immunology Feb 2012Knowledge of what constitute normal serum immunoglobulin (Ig) concentrations are important for the diagnosis of immunologic disorders. Data on normal Ig evaluated by...
Knowledge of what constitute normal serum immunoglobulin (Ig) concentrations are important for the diagnosis of immunologic disorders. Data on normal Ig evaluated by nephelometry are limited in healthy Asian children, none being available for Thai children. One hundred and forty-eight healthy Thai children aged 2-15 years were tested for serum immunoglobulins G, A, M, G1, G2, G3, and G4 (Ig G, A, M, G1, G2, G3, and G4) by nephelometry. Sixty-three percent were girls of median interquartile range age 6.9 (4.8-9.7) years. The geometric means for each Ig were summarized and categorized by age. Statistical analyses were used to compare Igs between sexes and age groups, and to compare IgG in this study with data from other published studies. The average ratios of IgG subclasses/IgG for Ig G1:2:3:4 were 66:22:5:7%. IgG, IgA, IgG2, and IgG3 concentrations showed a gradual increase with increasing age. There were no significant sex differences for any immunoglobulin isotype (P= 0.971). Our mean IgG concentration was lower than that measured by the radial diffusion method in healthy Thai children (P < 0.05). In all age groups, the mean IgG concentration in our study was significantly higher than that reported in Turkish and USA children, evaluated by the nephelometric and radial diffusion techniques, respectively (both P < 0.001). This study provides information about normal Ig concentrations measured by nephelometry in healthy Asian children and illustrates the importance of ascertaining normal Ig values for age- and ethnic-matched controls using the same assay to diagnose immunologic disorders correctly.
Topics: Adolescent; Child; Child, Preschool; Female; Humans; Immunoglobulin Isotypes; Male; Nephelometry and Turbidimetry; Thailand
PubMed: 22181033
DOI: 10.1111/j.1348-0421.2011.00413.x -
Optics Express Sep 2009We describe a family of dispersion-free and diffraction-free optical beams consisting in two-dimensional wave packets with a spatiotemporal Bessel (STB) profile...
We describe a family of dispersion-free and diffraction-free optical beams consisting in two-dimensional wave packets with a spatiotemporal Bessel (STB) profile propagating in media with anomalous dispersion. We also describe quasi-invariant optical beams with a spatiotemporal Bessel-Gauss (STBG) profile; these wave packets have finite dimensions and energy, conditions to be representative of physical beams. The paper provides a detailed account of the properties of STB and STBG beams, including their spatially resolved frequency spectrum, their far-field behaviour and a comparison of the propagation of STBG beams with that of Gaussian wave packets. An experimental setup based on a folded pulse shaper has allowed to generate STBG beams using the ultrashort pulses from a Ti:sapphire laser. The analysis of the spatially resolved frequency spectrum and of the spatial and temporal profiles obtained experimentally shows good agreement with theory.
Topics: Computer Simulation; Light; Lighting; Models, Theoretical; Nephelometry and Turbidimetry; Scattering, Radiation
PubMed: 19907605
DOI: 10.1364/OE.17.018148 -
Journal of Biomedical Optics Apr 2015We present the optical measurement techniques used in human skin phantom studies. Their accuracy and the sources of errors in microscopic parameters’ estimation of the...
We present the optical measurement techniques used in human skin phantom studies. Their accuracy and the sources of errors in microscopic parameters’ estimation of the produced phantoms are described. We have produced optical phantoms for the purpose of simulating human skin tissue at the wavelength of 930 nm. Optical coherence tomography was used to measure the thickness and surface roughness and to detect the internal inhomogeneities. A more detailed study of phantom surface roughness was carried out with the optical profilometer. Reflectance, transmittance, and collimated transmittance of phantoms were measured using an integrating-sphere spectrometer setup. The scattering and absorption coefficients were calculated with the inverse adding-doubling method. The reduced scattering coefficient at 930 nm was found to be 1.57±0.14 mm(−1) and the absorption was 0.22±0.03 mm(−1) . The retrieved optical properties of phantoms are in agreement with the data found in the literature for real human tissues.
Topics: Absorption, Radiation; Anisotropy; Biomimetic Materials; Equipment Design; Light; Models, Biological; Nephelometry and Turbidimetry; Phantoms, Imaging; Radiation Dosage; Refractometry; Skin; Skin Physiological Phenomena; Skin, Artificial; Tomography, Optical Coherence
PubMed: 25891198
DOI: 10.1117/1.JBO.20.4.045004