Semi-quantification Method Research Articles

Quantification and stability assessment of 7,9-di‑tert‑butyl‑1-oxaspiro(4,5)deca-6,9-diene-2,8‑dione leaching from cross-linked polyethylene pipes using gas and liquid chromatography.

This study assesses the formation and stability of the water contaminant 7,9-di‑tert‑butyl‑1-oxaspiro(4,5)deca-6,9-diene-2,8‑dione ([1]) which repeatedly occurs in the migration waters of cross-linked polyethylene (PE-X) pipes. In aqueous solution [1] is partially transformed to 3-(3,5-di‑tert‑butyl‑1‑hydroxy-4-oxo-2,5-cyclohexadien-1-yl)propionic acid ([2]). For a better understanding of the formation of [1] and its transformation into [2] an analytical method was established to allow the analysis of both species separately. Because of thermal instability [2] cannot be detected with GC-MS. Therefore, two methods were validated for a reliable and reproducible quantification: GC-MS for [1] and HPLC-MS/MS for both [1] and [2]. Comparative measurements of migration waters from PE-X pipes using GC-MS and HPLC-MS/MS methods showed that the concentrations of [1] detected with GC-MS corresponds to the sum of [1] and [2] measured with HPLC-MS/MS. In the migration waters [1] was detected in higher concentrations than [2]. The highest concentrations of [1], detected with GC-MS, were > 300µg/L. The longer the materials are stored without contact with water, the more [1] is measured in the migration waters. Most of the previous values reported in the literature for [1] were based on semi-quantification. Hence, we compared results of the semi-quantitative determination according to EN 15768 with those of a quantitative method with a standard. The results gained with the semi-quantitative method represent less than 50% of the quantified values for the amount leaching from the pipes, which means that the semi-quantification method according to EN 15768 leads to a significant underestimation of [1]. Finally, stability assessment showed that [1] developed an equilibrium with [2] under acidic conditions, whereas it will completely be transferred to [2] at pH 10. At pH 7, it takes more than 50 days for [1] to reach an equilibrium with [2]. However, at increasing the temperature to 60°C, [1] will be rapidly transformed into [2]. Besides [1] and [2], other currently unknown degradation products are formed. As there is no comprehensive toxicological assessment for both substances available today, our findings underline the need for regulatory consequences.

Semi-Quantification of Myocardial Uptake of Bone-Seeking Agents in Suspected Cardiac Amyloidosis

Bone scintigraphy has emerged as a key tool for non-invasive etiologic diagnosis of transthyretin (ATTR) cardiac amyloidosis (CA). We focused on a new semi-quantification method (on planar imaging) that could complement the qualitative/visual Perugini scoring system, especially when SPET/CT is not available. We retrospectively/qualitatively evaluated 8674 consecutive, planar 99mTc-biphosphonate scintigraphies (performed for non-cardiac reasons), identifying 68 (0.78%) individuals (mean age 79 ± 7 years, range 62-100 years; female/male ratio 16/52) presenting myocardial uptake. Due to the retrospective nature of the study, no SPET/CT, pathologic or genetic confirmation was obtained. The Perugini scoring system was determined (in patients presenting cardiac uptake) and compared with three newly proposed semi-quantitative indices. We took 349 consecutive bone scintigraphies, qualitatively absent of any cardiac/pulmonary uptake, as "healthy controls" (HC). The heart-to-thigh ratio (RHT) and lung-to-thigh ratio (RLT) indices were significantly higher in patients than in HCs (p ≤ 0.0001). There were statistically significant differences for RHT in HCs vs. patients with qualitative Perugini scores of 1 or >1 (with p ranging from ≤0.001 to ≤0.0001). ROC curves showed that RHT outperformed the other indices and was more accurate in both male and female groups. Furthermore, in the male population, RHT accurately distinguished HCs and patients with scores of 1 (less likely affected by ATTR) from patients with qualitative scores >1 (more likely affected by ATTR) with an AUC of 99% (sensitivity: 95%; specificity: 97%). The proposed semi-quantitative RHT index can accurately/semi-quantitatively distinguish between HCs and subjects probably affected by CA (Perugini scores from 1 to 3), and could be particularly useful when no SPET/CT data are available (such as in retrospective studies and data mining). Furthermore, RHT can semi-quantitatively predict, with very high accuracy, subjects in the male population more likely to be affected by ATTR. The present study, although using a very large sample, is however retrospective, monocentric, and therefore the generalizability of the results should be proved by an accurate external validation. The proposed heart-to-thigh ratio (RHT) can distinguish healthy controls and subjects that are probably affected by cardiac amyloidosis in a simple and more reproducible way, as compared to standard qualitative/visual evaluation.

The multicomponent residue depletion of Gelsemium elegans in pig tissues, urine, and plasma.

Gelsemium elegans (G. elegans) as a traditional medicinal plant used in livestock production. The use of G. elegans in veterinary clinics may pose safety risks to human health. The aim of this study was to investigate tissue residue depletion in pigs fed G. elegans powder. A precise quantitation method and a simultaneous semi-quantitation method for multiple components independently of standards in pig tissues were developed for the first time. The two methods were validated in terms of specificity, LODs, LOQs, linearity, accuracy, precision, and matrix effects. They were then applied to a tissue residue depletion study after G. elegans powder at a dose of 2% per kg feed were fed to pigs. Compared with precise quantitation, the method validation results indicated that the semi-quantitation method was reliable and acceptable for multicomponent quantification independent of standards. Many G. elegans alkaloids are widely distributed in most tissues of pigs. Tissue residue depletion studies indicated that 14-hydroxygelsenicine, 11-hydroxygelsenicine, and gelsemoxonine could be used as potential residue markers, and pancreas, small intestine, and lung tissues could be considered as potential residue target tissues of G. elegans. In addition, both urine and plasma could be used to predict 14-hydroxygelsenicine and gelsemoxonine residues in the liver, pancreas, and small intestinal tissues of pigs. The developed semi-quantification method can be applied to monitor the application and residue of G. elegans. The results provide scientific evidence for evaluating the safety of animal-derived food from G. elegans for consumers and will be helpful for its application and future development.

Identification and semi-quantification of metabolites of new plasticizers in urine collected from flemish adults and children

A suspect screening workflow combined with a semi-quantification method was applied for the investigation of metabolites of the plasticizers di-propylene glycol dibenzoate (DiPGDB) and tri-n-butyl trimellitate (TBTM) in human urine collected from adults and children during winter (W) and summer (S) seasons. Liquid chromatography - quadrupole time of flight mass spectrometry (LC-QTOF-MS) was applied for the analyses. Two direct and one indirect metabolites of DiPGDB were identified: 3-(3-hydroxypropoxy) propyl benzoate (DiPGDB-M194), 3,4,5-trihydroxy-6-[3-(3-hydroxypropoxy) propoxy] oxane-2-carboxylic acid (DiPGDB-M310), hippuric acid (DiPGDB-M179) and one metabolite of TBTM: bis(butoxycarbonyl) benzoyloxy]-3,4,5-trihydroxyoxane-2-carboxylic acid (TBTM-M498). The identified metabolites were reported with levels of confidence (LoC) 2 and 3 and their concentrations were assessed using a semi-quantification approach. The respective concentration ranges for W and S samples were 0.20–42 ng/mL and 0.07–29 ng/mL for DiPGDB-M194, 2.5–1420 ng/mL and 5.0–2320 ng/mL for DiPGDB-M310, 230–10840 ng/mL and 320–8420 ng/mL for DiPGDB-M179, and 0.40–30 ng/mL and 0.65–30 ng/mL for TBTM-M498. The detection frequency order in urine samples was DiPGDB-M310 = DiPGDB-M179 (100%) >TBTM-M498 (44%) > DiPGDB-M194 (28%) for W and DiPGDB-M179 (99%)> DiPGDB-M310 (98%) > TBTM-M498 (57%) > DiPGDB-M194 (30%) for S. The identified metabolites DiPGDB-M310, DiPGDB-M194 and TBTM-M498 are potential biomarkers for the evaluation of human exposure to DiPGDB and TBTM. DiPGDB-M179 cannot be used for the same purpose due to its formation from compounds with multi-source origin. The application of the semi-quantification method could be useful for further studies where analytical standards are not available.

First Novel Workflow for Semiquantification of Emerging Contaminants in Environmental Samples Analyzed by Gas Chromatography-Atmospheric Pressure Chemical Ionization-Quadrupole Time of Flight-Mass Spectrometry.

The ionization efficiency of emerging contaminants was modeled for the first time in gas chromatography-high-resolution mass spectrometry (GC-HRMS) which is coupled to an atmospheric pressure chemical ionization source (APCI). The recent chemical space has been expanded in environmental samples such as soil, indoor dust, and sediments thanks to recent use of high-resolution mass spectrometric techniques; however, many of these chemicals have remained unquantified. Chemical exposure in dust can pose potential risk to human health, and semiquantitative analysis is potentially of need to semiquantify these newly identified substances and assist with their risk assessment and environmental fate. In this study, a rigorously tested semiquantification workflow was proposed based on GC-APCI-HRMS ionization efficiency measurements of 78 emerging contaminants. The mechanism of ionization of compounds in the APCI source was discussed via a simple connectivity index and topological structure. The quantitative structure–property relationship (QSPR)-based model was also built to predict the APCI ionization efficiencies of unknowns and later use it for their quantification analyses. The proposed semiquantification method could be transferred into the household indoor dust sample matrix, and it could include the effect of recovery and matrix in the predictions of actual concentrations of analytes. A suspect compound, which falls inside the application domain of the tool, can be semiquantified by an online web application, free of access at http://trams.chem.uoa.gr/semiquantification/.

A novel workflow for semi-quantification of emerging contaminants in environmental samples analyzed by LC-HRMS.

There is an increasing need for developing a strategy to quantify the newly identified substances in environmental samples, where there are not always reference standards available. The semi-quantitative analysis can assist risk assessment of chemicals and their environmental fate. In this study, a rigorously tested and system-independent semi-quantification workflow is proposed based on ionization efficiency measurement of emerging contaminants analyzed in liquid chromatography-high-resolution mass spectrometry. The quantitative structure-property relationship (QSPR)-based model was built to predict the ionization efficiency of unknown compounds which can be later used for their semi-quantification. The proposed semi-quantification method was applied and tested in real environmental seawater samples. All semi-quantification-related calculations can be performed online and free of access at http://trams.chem.uoa.gr/semiquantification/ .

Semi-quantification of the binding constant based on bond breaking in a combined acoustic-gravitational field.

In this study, we propose a semi-quantification method based on breaking bonds between microparticles and glass plates in a combined acoustic-gravitational field. The semi-quantified binding constant values for BSA-ibuprofen, BSA-ciprofloxacin, ConA-glycogen, ConA-mannan, and BSA-naproxen calculated using this method were 7.5 × 103, 1.6 × 104, 2.3 × 105, 2.4 × 106 and 9.0 × 107 M-1, respectively, which were in concord with the reported values.

Effects of extraction pH on the volatile compounds from pea protein isolate: Semi-Quantification method using HS-SPME-GC-MS

HS-SPME-GC-MS is widely used to characterize the profile of volatile compounds despite some bad uses with a lack of information on the precision and repeatability of this technique. This work proposes a method, including a calibration step, to determine the global volatile compounds profile of a pea protein isolate at different pH of extraction. At the same time, nine compounds of interest were semi-quantified: hexanal, nonanal, 2-nonenal, 3-methylbutanal, benzaldehyde, 1-octen-3-ol, 3-octen-2-one, 2-pentylfuran, and 2,5-dimethylpyrazine. The variation coefficient of the method for a single fiber was 15%. Semi-quantification was done by external calibration. The global volatile compounds profile was composed of 39 compounds including 13 aldehydes, 9 alcohols, 13 ketones, and 4 furans. The quantification of the nine compounds of interest at different extraction pHs showed the importance of pH for aroma release from pea protein isolates. For example, hexanal release was found 59% higher with extraction using pH 4.5 than with pH 6.5.

Valoración de las fracciones de caseínas en leche de cabra Criolla y Saanen

The objective of the present work was to compare the values of the percentages of the different fractions in the milk casein of Criollo and Saanen goats. For this purpose, 6 adult goats of each breed from a commercial goat herd, located in the semi-arid region of central western Argentina, were evaluated. The goats were fed on alfalfa and corn grain, and service was performed by natural mating. Samples were collected by hand milking, taking 100 c.c./animal at 15, 30 and 45 days post-partum. To determine the percentage of alpha, beta and kappa casein, the UREA-PAGE vertical gel electrophoresis method was used and the bands were read applying the semi-quantification method with ImageJ software. The results found showed that in both breeds the values of alpha casein were increasing, while those of beta and kappa casein decreased throughout the sampling. Likewise, it was found that alpha casein was higher in Saanen goat milk, while the percentages of beta and kappa casein were higher in Criollo goat milk, finding a significant statistical difference for alpha and beta casein atthe three times evaluated and in the case of kappa casein only in the 45-day sampling. It was concluded that Criollo goat milk has a lower percentage of alpha casein than Saanen goat milk, which would make it less allergenic and has a higher percentage of beta and kappa casein, a situation that would allow a quick coagulation for cheese production.and a higher stability and firmness in yogurts.

Parametric Estimation of Reference Signal Intensity for Semi-Quantification of Tau Deposition: A Flortaucipir and [18F]-APN-1607 Study.

BackgroundTau positron emission tomography (PET) imaging can reveal the pathophysiology and neurodegeneration that occurs in Alzheimer’s disease (AD) in vivo. The standardized uptake value ratio (SUVR) is widely used for semi-quantification of tau deposition but is susceptible to disturbance from the reference region and the partial volume effect (PVE). To overcome this problem, we applied the parametric estimation of reference signal intensity (PERSI) method—which was previously evaluated for flortaucipir imaging—to two tau tracers, flortaucipir and [18F]-APN-1607.MethodsTwo cohorts underwent tau PET scanning. Flortaucipir PET imaging data for cohort I (65 healthy controls [HCs], 60 patients with mild cognitive impairment [MCI], and 12 AD patients) were from the AD Neuroimaging Initiative database. [18F]-APN-1607 ([18F]-PM-PBB3) PET imaging data were for Cohort II, which included 21 patients with a clinical diagnosis of amyloid PET-positive AD and 15 HCs recruited at Huashan Hospital. We used white matter (WM) postprocessed by PERSI (PERSI-WM) as the reference region and compared this with the traditional semi-quantification method that uses the whole cerebellum as the reference. SUVRs were calculated for regions of interest including the frontal, parietal, temporal, and occipital lobes; anterior and posterior cingulate; precuneus; and Braak I/II (entorhinal cortex and hippocampus). Receiver operating characteristic (ROC) curve analysis and effect sizes were used to compare the two methods in terms of ability to discriminate between different clinical groups.ResultsIn both cohorts, regional SUVR determined using the PERSI-WM method was superior to using the cerebellum as reference region for measuring tau retention in AD patients (e.g., SUVR of the temporal lobe: flortaucipir, 1.08 ± 0.17 and [18F]-APN-1607, 1.57 ± 0.34); and estimates of the effect size and areas under the ROC curve (AUC) indicated that it also increased between-group differences (e.g., AUC of the temporal lobe for HC vs AD: flortaucipir, 0.893 and [18F]-APN-1607: 0.949).ConclusionThe PERSI-WM method significantly improves diagnostic discrimination compared to conventional approach of using the cerebellum as a reference region and can mitigate the PVE; it can thus enhance the efficacy of semi-quantification of multiple tau tracers in PET scanning, making it suitable for large-scale clinical application.

A kinetics-based approach to amyloid PET semi-quantification.

To develop and validate a semi-quantification method (time-delayed ratio, TDr) applied to amyloid PET scans, based on tracer kinetics information. The TDr method requires two static scans per subject: one early (~ 0-10min after the injection) and one late (typically 50-70min or 90-100min after the injection, depending on the tracer). High perfusion regions are delineated on the early scan and applied onto the late scan. A SUVr-like ratio is calculated between the average intensities in the high perfusion regions and the late scan hotspot. TDr was applied to a naturalistic multicenter dataset of 143 subjects acquired with [18F]florbetapir. TDr values are compared to visual evaluation, cortical-cerebellar SUVr, and to the geometrical semi-quantification method ELBA. All three methods are gauged versus the heterogeneity of the dataset. TDr shows excellent agreement with respect to the binary visual assessment (AUC = 0.99) and significantly correlates with both validated semi-quantification methods, reaching a Pearson correlation coefficient of 0.86 with respect to ELBA. TDr is an alternative approach to previously validated ones (SUVr and ELBA). It requires minimal image processing; it is independent on predefined regions of interest and does not require MR registration. Besides, it takes advantage on the availability of early scans which are becoming common practice while imposing a negligible added patient discomfort.

Increased expression of protease-activated receptors 2 indicates poor prognosis in HBV related hepatocellular carcinoma

ObjectiveTo investigate the potential role of protease-activated receptor 2 (PAR2) in the prognosis of hepatocellular carcinoma (HCC).MethodsA total of 202 HCC patients who underwent liver resections were included. Tissue microarray was established with specimens of both HCC and paired adjacent liver tissues. PAR2 expression was detected by immunohistochemistry (IHC) assays.. A semi-quantification method was used to define the expression level of PAR2. The correlations between PAR2 expression and clinical features of patients with HCC was explored. The association of different PAR2 expressions with both overall survival and disease-free survival was analyzed.ResultsResults showed that the expression of PAR2 in HCC tissues was higher than that in paired para-cancerous liver tissues (4.12 ± 3.55 vs. 2.71 ± 2.56, P < 0.001). Higher expression of PAR2 was associated with poor differentiation (P < 0.001) and advanced tumor-node-metastasis stage (P = 0.015). Kaplan-Meier survival analysis indicated that HCC patients with high PAR2 expression had decreased overall survival (P = 0.033) and disease-free survival (P = 0.043) compared to patients with lower PAR2 expression. Multivariate analysis indicated that PAR2 expression (P = 0.032) was a significant independent prognostic factor for both overall survival and disease-free survival (P = 0.032; P = 0.032, respectively).ConclusionOur data revealed that PAR2 expression was increased in HCC. High PAR2 expression was correlated with both decreased overall survival and disease-free survival in patients with HCC. High PAR2 expression indicated a poor prognosis.

I-123 DaTscan SPECT Brain Imaging in Parkinsonian Syndromes: Utility of the Putamen-to-Caudate Ratio.

Computer-based analysis of Dopamine transporter imaging (DaTscan) can aid in image interpretation. In this study, we examined the distribution of putamen-to-caudate ratios (PCRs) obtained by using a clinically available semiquantification method. Medical records of 32 patients (M:16) with a diagnosis of Parkinson's disease (PD) (n = 22) or Parkinson's plus syndromes (PPS) (n = 10) based on clinical follow-up, were retrospectively reviewed. Single photon emission tomography (SPECT) imaging was performed 4 hours after intravenous injection of 3-5 mCi [I-123]-ioflupane. Semiquantitative evaluation using DaTQUANT software was performed. Utility of PCR with a cutoff of .7 and .8 in the diagnosis of nigrostriatal degeneration was assessed. PD and PPS groups based on clinical assessment and caudate-to-background ratio (CBR) were assessed separately. Minimum PCR for both hemispheres was .74 ± .09 (Mean ± SD, range: .58-.89), with 65.63% patients (21/32) having PCR > .7. Mean PCR in mild nigrostriatal degeneration was .77 ± .08 (range: .62-.89) and in advanced nigrostriatal degeneration was .73 ± .09 (range: .58-.89). Mean PCR in PD group was .73 ± .09 (range: .58-.89) and in PPS group was .75 ± .10 (range: .61-.88). Although PCR can intrinsically be a useful indication of disease, this ratio obtained in our analysis by using one of the clinically available automatic semiquantitative methods has large variability and might not be a reliable numeric marker in interpretation of [I-123]ioflupane studies. This may be due to difficulty in separating caudate from putamen on SPECT images, as well as the nonuniform decreased Ioflupane uptake in both putamen and caudate.

A comprehensive profile and inter-individual variations analysis of the human normal amniotic fluid proteome

Amniotic fluid contains large amounts of proteins produced by amnion epithelial cells, fetal tissues, fetal excretions and placental tissues; thus, it is an important potential source of biomarkers for identifying fetal pathologies. In this study, a pooled AF sample from 7 healthy volunteers was used to provide a comprehensive profile of normal human AF proteome using immunoaffinity depletion of 14 high-abundance proteins. Each individual AF sample was used to analyze inter-individual variations with iTRAQ method. As a result, a total of 2881 non-redundant proteins were identified, and 1624 proteins were quantified based on the peak intensity-based semi-quantification (iBAQ) method. Gene Ontology (GO) analysis showed that the AF proteome was enriched in extracellular region and extracellular matrix. Further function annotation showed that the top canonical pathway was axonal guidance signaling. The inter-individual variation analysis of 7 individual AF samples showed that the median inter-individual CV (Coefficient of variation) was 0.22. iBAQ quantification analysis revealed that the inter-individual variations were not correlated with protein abundance. GO analysis indicated that intracellular proteins tended to have higher CVs, and extracellular proteins tended to have lower CVs. These data will contribute to a better understanding of amniotic fluid proteomic analysis and biomarker discovery. SignificanceAmniotic fluid is an important potential source of biomarkers for identifying fetal pathologies. This study provided a large database for the normal human amniotic fluid proteome and analysis of inter-individual variations in amniotic fluid proteomes, which will offer a baseline reference for further AF proteomic analysis and pregnancy-related disease biomarker discovery.

Investigating the organic and conventional production type of olive oil with target and suspect screening by LC-QTOF-MS, a novel semi-quantification method using chemical similarity and advanced chemometrics.

The discrimination of organic and conventional production has been a critical topic of public discussion and constitutes a scientific issue. It remains a challenge to establish a correlation between the agronomical practices and their effects on the composition of olive oils, especially the phenolic composition, since it defines their organoleptic and nutritional value. Thus, a liquid chromatography-electrospray ionization-quadrupole time of flight tandem mass spectrometric method was developed, using target and suspect screening workflows, coupled with advanced chemometrics for the identification of phenolic compounds and the discrimination between organic and conventional extra virgin olive oils. The method was optimized by one-factor design and response surface methodology to derive the optimal conditions of extraction (methanol/water (80:20, v/v), pure methanol, or acetonitrile) and to select the most appropriate internal standard (caffeic acid or syringaldehyde). The results revealed that extraction with methanol/water (80:20, v/v) was the optimumsolvent system and syringaldehyde 1.30mgL-1 was the appropriate internal standard. The proposed method demonstrated low limits of detection in the range of 0.002 (luteolin) to 0.028 (tyrosol) mgkg-1. Then, it was successfully applied in 52 olive oils of Kolovi variety. In total, 13 target and 24 suspect phenolic compounds were identified. Target compounds were quantified with commercially available standards. A novel semi-quantitation strategy, based on chemical similarity, was introduced for the semi-quantification of the identified suspects. Finally, ant colony optimization-random forest model selected luteolin as the only marker responsible for the discrimination, during a 2-year study. Graphical abstract Investigation of the organic and conventional production type of olive oil by LC-QTOF-MS.

Introduction of a metabolic joint asymmetry score derived from conventional bone scintigraphy. A new tool to differentiate psoriatic from rheumatoid arthritis.

Clinical differentiation of psoriatic arthritis (PsA) and rheumatoid arthritis (rA) based on the pattern of joint involvement can be difficult; the frequent form of PsA with polyarthritis of the peripheral joints may sometime resemble rA. We investigated a metabolic joint asymmetry score (MJAS), reflecting the overall asymmetric joint involvement on conventional bone scintigraphy, for differentiating PsA from rA in patients presenting with peripheral polyarthritis. 106 patients (n = 61, PsA; n = 45, rA) with peripheral polyarthritis (≥ 5 joints) as well as 26 control subjects with no history of chronic joint disorders were analyzed. The intensity of articular 99mTc-MDP uptake in 40 peripheral joint pairs was scored regarding the bilateral difference of each joint based on a scale of 0-2 (no significant, moderate, and marked asymmetry, respectively). The patient's MJAS was defined as the sum of uptake difference scores of all joint pairs. The association of MJAS with the underlying condition (Psoriasis criteria, Revised Criteria of the ACR) was examined. 5280 peripheral joint pairs were investigated. There was no significant difference in the total number of involved joints in PsA 15.0 ± 8.2 versus rA 17.5 ± 8.8 patients (p = 0.132), but significantly less involvement in the control group (6.7 ± 5.0, p < 0.001). MJAS was markedly higher in PsA (17.0 ± 9.6) than in rA (4.8 ± 3.9, p < 0.001), and correlated with the total number of involved joints in PsA (r= 0.516, p < 0.001), but not in rA (r = 0.078, p = 0.380). The MJAS disparity between PsA and rA persisted after exclusion of the DIP joints (14.4 ± 7.7 vs. 4.4 ± 3.3; p<0.001). The new reproducible semi-quantification method for the asymmetry of metabolic joint involvement permits differentiation of psoriatic from rheumatoid peripheral arthritis with MJAS being markedly higher in patients with PsA as compared to rA patients. The score may offer an effective complementary tool for characterizing patients with peripheral polyarthritis.

A high throughout semi-quantification method for screening organic contaminants in river sediments

A high throughout semi-quantification method for screening nearly 900 organic contaminants (OCs) in river sediments has been developed. For most OCs tested, concentrations calculated from the proposed semi-quantification method deviated from actual values by a factor of 4. The overall recovery tests indicated that most OCs can be successfully extracted from sediments with recovery rates from 84.1 to 128.6%. To demonstrate the effectiveness of our method towards OC quantification, we screened OCs from sediments collected from the Haihe River basin. Seventy unregulated OCs (including pesticides, flame retardants, PPCPs, etc.) were identified and quantified at concentrations up to 2600 ng/g from 24 sediment samples. From these results, it is confirmed that the developed method is a useful way to fulfill a comprehensive analysis of OCs in sediments and would be valuable for the identification and prioritization of priority pollutants in watershed management.

Evaluation of point-of-care testing of C-reactive protein in forensic autopsy cases

We assessed the technical performance and robustness of the point-of-care test for C-reactive protein (CRP) NycoCard CRP for use in forensic autopsy cases. The results of 17 of 39 cadaver blood samples that had CRP in the range effectively measured by the NycoCard (5–120mg/l) correlated well (r=0.99) with those of quantitative latex agglutination immunoassay (turbidimetry), and the out-of-range NycoCard results were fully consistent with those obtained by turbidimetry. For the ten sera whose CRP >120mg/l according to NycoCard, a significant correlation (r=0.98) was observed between values multiplied by the dilution ratio and those of turbidimetry. No significant differences were observed after a freeze–thaw procedure. In addition, CRP results using recombinant human CRP spiked with hemoglobin up to 80g/l were not significantly different from the unspiked results in PBS. The test allows reliable and cost-effective on-site measurement of CRP from a small volume of serum (5μl) with simple equipment. This semi-quantification method of CRP should be useful for diagnosis during autopsy.

Creatine Transporter Immunolocalization in Aged Human and Detached Retinas

To identify the distribution of creatine transporter (CRT) in the aged human retina and how this expression pattern is modified after retinal detachment. An affinity-purified antibody raised against the CRT was used in the immunohistochemical investigation. The anti-CRT antibody was colocalized with neuronal markers (calbindin, parvalbumin, Islet-1, calretinin, GAD₆₇, Go-alpha), glia markers (glutamine synthetase, glial fibrillary acid protein), and a blood vessel basal membrane marker (laminin). Confocal microscopy was used to visualize the labeling patterns in retinal sections. The level of CRT expression was determined in the retina using a semiquantification method. Immunohistochemical assessment of CRT expression in the normal aged retina revealed strong labeling in photoreceptor synaptic terminals and in inner and outer segments. Labeling was also observed on subpopulations of amacrine cells and ganglion cells as well as in the outer and inner plexiform layers. CRT labeling was observed in blood vessels, although was absent in glial cells. In retinal detachment, the CRT labeling pattern was maintained, although there was an apparent decrease in labeling in inner retina and an increase in CRT expression in photoreceptors. CRT is expressed in areas of intense metabolic activity, such as photoreceptors, selected cells in the inner retina, and sites of creatine transport into the retina (inner retinal blood vessels and retinal pigment epithelium). The absence of CRT to Müller cells harmonizes with the concept that glial cells are a biosynthetic source of creatine but not a source of creatine to other retinal neurons. The increased immunolabeling of CRT localized to the outer retina in retinal detachment suggests a regional metabolic remodeling occurring in photoreceptor cells.

Identification of N-homocysteinylated apolipoprotein AI in normal human serum

In human serum, a portion of homocysteine (Hcy) exists as an N-linked form to the epsilon-amino group of protein lysine residues. N-homocysteinylated proteins differ structurally and functionally from native proteins. The present study strives to develop detection and potential semi-quantification methods for N-homocysteinylated apolipoprotein AI (N-Hcy-apoAI) in human serum. Serum treated with or without cysteamine was supplied to isoelectric focusing (IEF) followed by an immunoblot using an anti-apoAI antibody. Cysteamine treatment increased the isoelectric point for N-Hcy-apoAI, but not for unmodified apoAI, due to the presence of -SH group(s) derived from Hcy and the absence of a cysteine residue in the apoAI molecule. N-Hcy-apoAI was semi-quantified from the scanned immunoblot pattern via a computer. After cysteamine treatment, N-Hcy-apoAI in the serum was identified by IEF at the position with a higher pI value compared with intact apoAI. The reproducibility (between assays) of the semi-quantification method was 19.1% CV (coefficient of variation) for an average ratio 5.9% of N-Hcy-apoAI to the whole apoAI in the serum. Approximately 1.0-7.4% of apoAI was N-homocysteinylated in the serum obtained from 27 healthy subjects. Neither the ratio of N-Hcy-apoAI nor its concentration, calculated by total apoAI concentration, indicated correlation with the so-called total (free and S-linked) Hcy concentration. We directly found that a portion of apoAI in the serum undergoes homocysteinylation in an N-linkage manner, and used this to develop a potential semi-quantification method for N-Hcy-apoAI.