Association of TLR2 and TLR4 non-missense single nucleotide polymorphisms with type 2 diabetes risk in a southern Chinese population: a case-control study.

Toll-like receptors (TLRs), the triggers of the innate and adaptive immune responses, are involved in the pathogenesis of type 2 diabetes mellitus (T2DM). Several studies have investigated the effects of genetic polymorphisms in TLR4 and TLR2, but they have yielded limited results. We investigated whether non-missense genetic polymorphisms in the regulatory regions of TLR4 and TLR2 were related to T2DM in a southern Chinese population. Single nucleotide polymorphisms (SNPs) in TLR4 (rs1927911, rs11536889, rs1927907, rs1927906, rs1927914, rs7873784, and rs2149356) and TLR2 (rs1898830, rs3804099, rs4696480, and rs3804100) were genotyped in 552 T2DM and 552 unrelated age- and gender-matched controls by SNaPShot Multiplex assay. Genotypes GG (OR = 0.09, 95%CI = 0.01- 0.83, P = 0.03) and CG (OR = 0.08, 95%CI = 0.01-0.74, P = 0.03) of the 3'-untranslated region (UTR) SNP rs7873784 in TLR4, and genotype AG (OR = 0.67, 95%CI = 0.46-0.97, P = 0.04) and allele G (OR = 0.88, 95%CI = 0.79-0.97, P = 0.01) of the intron SNP rs1898830 in TLR2 were identified as protective against the development of T2DM in southern Chinese people. In contrast, a meta-analysis of rs1927911 and rs1927914 showed no association. Haplotypes AGTT (OR = 0.34, 95%CI = 0.15-0.77, P = 0.01) and AATT (OR = 1.20, 95%CI = 1.01- 1.44, P = 0.05) in TLR2 were significantly associated with susceptibility to T2DM. Our results suggest that the effects of non-missense polymorphisms located in the regulatory regions of TLR4 and TLR2 should not be neglected in T2DM association analysis.

Inadequate values from an interferon-gamma release assay for smear-negative tuberculosis in a high-burden setting.

OBJECTIVE: To examine the usefulness of an interferon-gamma release assay (IGRA) for the diagnosis of smear-negative tuberculosis (TB) in China. DESIGN: A total of 624 patients with presumed pulmonary TB were enrolled prospectively and categorised as smear-negative TB, smear-positive TB or no TB. All patients were tested using T-SPOT.TB. RESULTS: Both the smear-negative and smear-positive TB groups had significantly more spot-forming cells (SFCs) than the no TB group (all P < 0.001), while the smear-negative group had fewer SFCs than the smear-positive TB group (P < 0.001). The specificity of T-SPOT.TB was 60.4% (95%CI 53.4-67.1). The sensitivities of T-SPOT.TB in the smear-negative and smear-positive TB groups were respectively 81.4% (95%CI 75.7-86.0) and 93.2% (95%CI 87.6-96.4). The sensitivity in the smear-negative TB group was much lower than that in the smear-positive TB (P < 0.05). CONCLUSIONS: The sensitivity of T-SPOT.TB was lower due the paucibacillary nature of the samples, and the specificity was lower due to the high prevalence of latent tuberculous infection in the smear-negative TB patients. The T-SPOT.TB test should only be used as a supplementary test and not as a single test to rule in or rule out smear-negative TB.

In vivo quantification of lead in bone with a portable x-ray fluorescence system--methodology and feasibility.

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (intraclass correlation coefficient, ICC = 0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC = 0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 µSv and should pose minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements.

Ion chromatographic determination of calcium and magnesium cations in human saliva and urine with a piezoelectric detector.

In this present paper, simultaneous determination of Ca(2+) and Mg(2+) cations in saliva, urine was achieved using an ion chromatography method, in which a piezoelectric quartz crystal (PQC) sensor was used as a detector, and a solution containing tartaric acid (4 mmol 1(-1)) and ethylenediamine (2 mmol 1(-1)) as a mobile phase. Good linearities were obtained over the ranges of 0.8-500 mg 1(-1) Ca(2+) and 1.0-500 mg 1(-1) Mg(2+). The detection limits were 0.4 mg 1(-1) for Ca and 0.2 mg 1(-1) for Mg, respectively.

Simultaneous determination of nitrate and nitrite in saliva and foodstuffs by non-suppressed ion chromatography with bulk acoustic wave detector.

In the present paper, nitrate and nitrite in foodstuffs and saliva were simultaneously determined using a non-suppressed ion chromatography (IC) method with a bulk acoustic wave sensor (BAW) as detector, and 1.5 mmol/L potassium hydrogenphthalate (KHP) as mobile phase. The IC-BAW method is simple, rapid and accurate. The determination limits for nitrite and nitrate are 0.20 and 0.30 mg/L, respectively. The IC-BAW is comparable and agrees with the conventional spectrophotometric method for nitrite and nitrate determination.

Determination of the binding parameters of drug to protein by equilibrium dialysis/piezoelectric quartz crystal sensor.

A novel method, equilibrium dialysis/piezoelectric quartz crystal sensor, applied to determine the binding parameters of diethyldithiocarbamate to human plasma protein is proposed. Based on the investigation of the equilibrium reaction for the binding of drug to protein, the related theoretical equations for this binding were derived. By monitoring the frequency responses of a copper-plated piezoelectric quartz crystal sensor to drug in and out of a dialysis membrane after equilibrium, the binding parameters were determined, i.e., 0.375 micromol g(-1) for beta(p), 6.496 microM for K(dp), 141.99 L mmol(-1) for K(p), and 0.043 for N. These values were in good agreement with reference values. It was found that this method may have application for studying the characteristics of the interaction between other drugs and proteins.

Flow-injection determination of total ammonia and total carbon dioxide in blood based on gas-diffusion separation and with a bulk acoustic wave impedance sensor.

A novel flow-injection (FIA) system, for the rapid and direct determination of both total ammonia (T[NH3]) and total carbon dioxide (T[CO2]) in clinical blood samples, has been developed. Samples were injected into a carrier stream of H2O, then emerged with a reagent stream, where the analyte was converted into a gaseous species and diffused across a PTFE gas-permeable membrane into an acceptor stream. The trapped NH3/CO2 in the acceptor was determined on line by a bulk acoustic wave (BAW) impedance sensor. At a through-put of 20 and 65 h(-1), the proposed system exhibited a linear frequency response up to 200 micromol l(-1) ammonium and 20 mmol l(-1) bicarbonate with a detection limit of 1.0 and 10 micromol l(-1), respectively. Results obtained for T(NH3) in serum and T(CO2) in plasma were in agreement with those obtained by the conventional glutamate dehydrogenase (GDH) method and gas-sensing electrode method, respectively. The effects of composition of acceptor stream, cell constant of conductivity electrode, sample volume, flow rate and potential interferents on the FIA signals were also discussed.

Ion chromatographic study of sodium, potassium and ammonium in human body fluids with bulk acoustic wave detection.

In the present paper, determination of Na+, K+ and NH4+ in saliva and serum was carried out using an ion chromatography (IC) method with a bulk acoustic wave (BAW) sensor as detector and 2.0 mmol/l nitric acid as mobile phase. The IC-BAW method is simple, rapid and accurate. Comparison between the BAW detector and the conventional conductivity detector (CDD) was discussed. The IC-BAW showed agreement with the commonly used flame photometric method for Na+ and K+ and enzymatic method for NH4+, as well as IC-CDD for those three cations.

Determination of ammonium in Kjeldahl digests by gas-diffusion flow-injection analysis with a bulk acoustic wave-impedance sensor.

A novel flow-injection analysis (FIA) system has been developed for the rapid and direct determination of ammonium in Kjeldahl digests. The method is based on diffusion of ammonia across a PTFE gas-permeable membrane from an alkaline (NaOH/EDTA) stream into a stream of diluted boric acid. The trapped ammonium in the acceptor is determined on line by a bulk acoustic wave (BAW)-impedance sensor and the signal is proportional to the ammonium concentration present in the digests. The proposed system exhibits a favorable frequency response to 5.0 x 10(-6)-4.0 x 10(-3) mol l(-1) ammonium with a detection limit of 1.0 x 10(-6) mol l(-1), and the precision was better than 1% (RSD) for 0.025-1.0 mM ammonium at a through-put of 45-50 samples h(-1). Results obtained for nitrogen determination in amino acids and for proteins determination in blood products are in good agreement with those obtained by the conventional distillation/titration method, respectively. The effects of composition of acceptor stream, cell constant of conductivity electrode, sample volume, flow rates and potential interferents on the FIA signals were discussed in detail.

Determination of dipyridamole by modified extraction-gravimetry with a surface acoustic wave resonator sensor.

A simple and sensitive extraction-gravimetric method for the determination of dipyridamole is presented. The method is based on the extraction of free dipyridamole with chloroform, after neutralization with a basic agent, followed by measurement of the frequency shift response of the specially designed surface acoustic wave resonator sensor after evaporation of the extractant from the surface of the resonator. The frequency shift response was proportional to the amount of dipyridamole in the range 0.065-1.12 micrograms. Experimental parameters and the effect of interfering substances on the assay of dipyridamole were also examined in this study. The method was applied to the determination of dipyridamole in tablets.

Bulk acoustic wave sensor for investigating hemorheological characteristics of plasma and its coagulation.

A method of using a bulk acoustic wave (BAW) device to study the hemorheological phenomena is proposed. By measuring the resonant resistance of a BAW device, the dependence of the plasma viscosity on its composition is investigated. It has been found that during the process of the plasma coagulation, the frequency response of a BAW device is dominated by the change in plasma viscoelasticity, and useful information such as the coagulation time and the viscoelasticity of coagulated plasma can be obtained from the curve of frequency response. Based on the BAW quartz detection system, effects of fibrinogen, thrombin and some drugs on the plasma coagulation are investigated. The results show that the BAW device based on the oscillator method possesses some advantages, such as high sensitivity, simplicity of use, cost effectiveness and small sample volume for clinical hemorheological study.

Determination of lactic acid and pyruvic acid in serum and cerebrospinal fluid by ion-exclusion chromatography with a bulk acoustic wave detector.

A chromatographic method base don a combination of ion-exclusion chromatography separation and bulk acoustic wave series piezoelectric quartz crystal detector quantification for the determination of pyruvic acid and lactic acid in serum and cerebrospinal fluid (CSF) was developed. The separation was carried out using a Shim-pak SCR-102H ion-exclusion column with phosphoric acid solution as eluent. The method shows an acceptable detection limit and anti-interference ability. Serum and CSF from healthy individuals and patient were analysed successfully.

Application of a series piezoelectric sensor as a detector in ion chromatography.

The application of a series piezoelectric sensor as a detector for ion chromatography (IC) is investigated. The device is used with sensitive response between the series piezoelectric quartz crystal oscillation frequency and specific conductivity of liquids for ion chromatographic detection. Two platinum wires are used as conductivity electrodes and inserted oppositely in the detection cell. The dead-volume of the detection is 15 microL, the noise is less than or equal to 1 Hz, the baseline drift is 5 Hz/h, and the detection limits of F- and Na+ are 5 and 25 ng, respectively. The effects of temperature, background conductivity, cell constant of the conductivity electrode, and dead volume on the sensitivity of the detector are discussed. The detector temperature should equal that of the column. An optimum sensitivity is obtained when the cell constant is approximately 3.5 cm. The optimum range of the background conductivity of the mobile phase is 150 to 1200 microseconds. When the solution conductivity is greater than 3000 microseconds, the detector does not work satisfactorily. The proposed IC cerebrospinal fluid detection method is applied to the determination of vitamin C in apple and Zn2+, Ca2+, Mg2+, and Cu2+ in human cerebrospinal fluid.

Electropolymerized m-phenylenediamine as a means to immobilize active protein on thickness-shear-mode quartz crystal.

Electropolymerized m-phenylenediamine was used as an active coating for immobilizing urease and lectin on a gold-plated thickness-shear-mode (TSM) crystal. To enhance effectiveness of immobilization. a bilayer polymer film composed of polyaniline and poly-m-phenylenediamine was proposed. Compared with single poly-m-phenylenediamine film, the bilayer polymer film gave better results in terms of immobilizing capacity, stability and reproductivity. On this bilayer-film-coated TSM quartz crystal, the amount of immobilized lectin was estimated about 1.8 mug/cm(2). Detection of purified human erythrocytes is demonstrated as an example of potential application of this lectin-modified TSM biosensor in clinic.

Reaction-frequencymetric method: a new analytical technique for determination of submicromolar concentration levels of vitamin C.

A new analytical technique for the assay of pharmaceutical substances at low concentration levels has been proposed and applied to the determination of vitamin C as an example of its application. It is based on the chemical reaction of vitamin C with iodine in a sodium citrate-hydrochloric acid medium, followed by measurement of the frequency change of a silver-plated piezoelectric quartz crystal. The frequency change is proportional to the vitamin C concentration from 2 x 10(-7) to 4 x 10(-6) M. The method was applied to the assay of vitamin C in pharmaceutical preparations.

[Simultaneous determination of vitamin B1 and vitamin C in aqueous solution with piezoelectric crystal quartz sensors].

According to the response properties of piezoelectric crystal quartz sensors to the solution conductivity the frequency shift response was derived to show a linear dependence on the concentrations of vitamin B1 (VB1) and vitamin C (VC). This was experimentally verified and a calibration model for simultaneous determinations of the two vitamins was established. The usefulness of the technique was evaluated by quantitation of mixtures of unknown composition using common multiple linear regression (MLR) and partial least squares (PLS). The average relative standard deviations for six samples were 4.46% for VB1 and 6.63% for VC with MLR; and 1.97% for VB1 and 2.74% for VC with PLS, respectively.

Determination of sulpha-drugs with a piezoelectric sensor.

A piezoelectric sensor is used for the determination of sulpha-drugs, as pure substances and in their dosage forms, by an indirect micro method based on reaction of the sulpha-drug with bromine and reduction of the resultant N-bromoderivative with iodide to form iodine, which after extraction is monitored with a piezoelectric quartz sensor. The response of the sensor is linear from 2 x 10(-5) to 4 x 10(-4)M sulpha-drug.

Extraction-frequencymetric method. A new measurement technique for determination of micro amounts of chlorpheniramine.

A new measurement technique has been proposed and applied to the determination of chlorpheniramine as an example of its application. It is based on the extraction of free chlorpheniramine into carbon tetrachloride after neutralization with a basic agent, followed by measurement of the frequency change of the specially designed ring-coated piezoelectric sensor after evaporation of the extractant from the crystal surface. The frequency change is proportional to the chlorpheniramine amount in the range 0.025-1.2 microgram. The method has been applied to the determination of chlorpheniramine maleate in pharmaceutical preparations.

Transfer mechanism of quinine drug across the oil/water (O/W) interface.

The transfer phenomena of quinine drug at the aqueous 1,2-dichloroethane (DCE) interface have been studied by the current-scanning polarography. The relationships between the wave height and pH of aqueous phase, concentration of quinine as well as the rate of water drop are discussed. The effect of supporting electrolyte, buffer solution and the nature of organic solvent on the polarographic wave is studied. The transfer characteristics of quinine in aqueous phase and in organic phase are compared. The mono-protonated and diprotonated quinines can both transfer at the interface so as to produce two polarographic waves. The transfer process of quinine at the interface is simultaneously controlled by diffusion and reestablishment of the disturbed protonated equilibrium of quinine. A further investigation is made by chronopotentiometry. On the basis of the theoretical analysis, the formulae of the limiting current are derived and discussed. The theoretical results are in agreement with the experimental ones. The transfer mechanism of quinine is put forward.