Preimplantation genetic testing for aneuploidy helps to achieve a live birth with fewer transfer cycles for the blastocyst FET patients with unexplained recurrent implantation failure.

PURPOSE: This retrospective cohort study aimed to investigate the value of preimplantation genetic testing for aneuploidy (PGT-A) as a screening test for patients suffering from unexplained recurrent implantation failure (RIF). METHODS: After screening patients in one reproductive medicine center, twenty-nine, forty-nine and thirty-eight women (< 40 years old) who had suffered unexplained RIF with PGT-A, or RIF without PGT-A, or no RIF with PGT-A were included. The clinical pregnancy rate and live birth rate per transfer, the conservative and optimal cumulative clinical pregnancy rates (CCPR) and live birth rates (CLBR) after three blastocyst FETs were analyzed. RESULTS: The live birth rate per transfer was significantly higher in the RIF + PGT-A group than that in the RIF + NO PGT-A group (47.6% vs. 24.6%, p = 0.014). After 3 cycles of FET, RIF + PGT-A group had significantly higher conservative CLBR and optimal CLBR compared to the RIF + NO PGT-A group (69.0% vs. 32.7%, p = 0.002 and 73.7% vs. 57.5%, p = 0.016), but had similar conservative and optimal CLBRs compared to the NO RIF + PGT-A group. The number of FET cycles required when half women achieved a live birth was 1 in the PGT-A group and 3 in RIF + NO PGT-A group. The miscarriage rates were not different between the RIF + PGT-A and RIF + NO PGT-A, RIF + PGT-A and NO RIF + PGT-A groups. CONCLUSION: PGT-A did be superior in reducing the number of transfer cycles required to achieve a similar live birth rate. Further studies to identify the RIF patients who would benefit most from PGT-A are necessary.

Resveratrol Nanoparticles Suppresses Migration and Invasion of Renal Cell Carcinoma Cells by Inhibiting Matrix Metalloproteinase 2 Expression and Extracellular Signal-Regulated Kinase Pathway.

The aim of this study was to examine the impact of Resveratrol nanoparticles on migration/invasion capacity of renal cell carcinoma (RCC) cells and its mechanism. Human RCC cells were exposed to dimethyl sulfoxide or gradient concentrations of Resveratrol nanoparticles respectively, and U0126 were also added in some experiments. We examined renal cell viability by MTT assay, and wound healing test and Transwell assays were used detect invasion and migration capability of RCC cells. We used Western blotting assay to analyze the protein levels in extracellular signal-regulated kinase (ERK) signaling. We also detected the enzymatic capacity of matrix metalloproteinase 2 (MMP-2) in cells by gelatin enzymatic profiling. Resveratrol nanoparticles treatment significantly suppressed cell viability to migrate and invade RCC cells in a dose-dependent manner. Also, notably were reduced MMP-2 activity and expression, and elevated TIMP-2 level were observed in RCC cells exposed with Resveratrol nanoparticles. Further, Resveratrol nanoparticles treatment significantly decreased only the expression of p-ERK1/2, but not p-p38 and p-JNK. Moreover, U0126, which is the ERK inhibitor, exerted similar role as Resveratrol nanoparticles did. Of note was that, combined use of U0126 and Resveratrol nanoparticles displayed a more intense suppression of MMP-2 activity and expression, and also the viability to migrate and invade the RCC cells, compared with Resveratrol nanoparticles treatment alone. The Resveratrol nanoparticles inhibited RCC cells migration and invasion by regulating MMP2 expression and ERK pathways.

SKA-31-induced activation of small-conductance calcium-activated potassium channels decreased modulation of detrusor smooth muscle function in a rat model of obesity.

Increased excitability and contractility of detrusor smooth muscle (DSM) cells are associated with overactive bladder (OAB), which is often induced by obesity. Small-conductance Ca2+-activated K+ (SK) channels regulate the excitability and contractility of DSM cells. Selective pharmacological activation of SK channels attenuates hyperpolarization and the decreased relaxation effect in DSM cells in obesity-induced OAB. However, additional data are needed to confirm the regulatory effect of SK channels on the function of DSM cells in obesity-related OAB. The tested hypothesis was that activation of SK channels decreases modulation of DSM function in a rat model of obesity-related OAB. Female Sprague Dawley rats were fed a normal diet (ND) or a high-fat diet (HFD), weighed after 12 weeks, and subjected to urodynamic study, patch-clamp electrophysiology, and isometric tension recording. The average body weight and incidence of OAB were increased in the HFD group. Patch-clamp studies revealed that pharmacological activation of SK channels with SKA-31 had attenuated hyperpolarization of DSM cells. In addition, isometric tension recordings indicated that SKA-31 decreased relaxation of spontaneous phasic contractions of DSM strips in the HFD group. Attenuated function of SK channels increased the excitability and contractility of DSM cells, which contributed to the occurrence of OAB, suggesting that SK channels are potential therapeutic targets for control of OAB.

Nodal is involved in chemoresistance of renal cell carcinoma cells via regulation of ABCB1.

Renal cell carcinoma (RCC) is the third most frequent malignancy within urological oncology. Understanding mechanisms of chemoresistance in RCC cell is important for therapy and drug development. We established cisplatin (CDDP) resistant RCC cells by treating cells with increasing concentrations of CDDP. Nodal, an important embryonic morphogen, was increased in RCC/CDDP cells. Targeted inhibition of Nodal via its siRNA or neutralization antibody restored sensitivity of RCC resistant cells to CDDP treatment. It was due to that si-Nodal can decrease expression of P-glycoprotein (P-gp, encoded by ABCB1), one important ATP-binding cassette (ABC) membrane transporter for drug efflux. si-Nodal can decrease the transcription and promoter activity of ABCB1. Mechanistically, si-Nodal can decrease the phosphorylation of p65, which can bind to the promoter of ABCB1 and then trigger its transcription. Further, CDDP treatment decreased the expression of Nodal in culture medium of RCC cells. Collectively, we found that Nodal can regulate chemoresistance of RCC cells via regulating transcription of ABCB1.

LncRNA KCNQ1OT1 facilitates the progression of bladder cancer by targeting MiR-218-5p/HS3ST3B1.

Long non-coding RNA (lncRNA) is characterized by biological function in diverse cancers. LncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) is well acknowledged to regulate various cancers, while its role in bladder cancer remains unclear. In the present study, we aimed at probing into the impact and detailed mechanisms of KCNQ1OT1 in bladder cancer progression. In this study, we demonstrated that KCNQ1OT1 expression in bladder cancer tissues was notably up-regulated compared with in normal adjacent tissues, and KCNQ1OT1 modulated the malignant phenotypes of bladder cancer cells. Moreover, it was validated that KCNQ1OT1 could specifically bind to miR-218-5p and reduce its expression. Overexpressed miR-218-5p would inhibit the proliferation and metastasis of bladder cancer cells while facilitating apoptosis. In terms of Mechanism, Heparan Sulfate-Glucosamine 3-Sulfotransferase 3B1 (HS3ST3B1) was validated as a target gene of miR-218-5p, and could be regulated by KCNQ1OT1 indirectly. In conclusion, KCNQ1OT1 can promote the progression of bladder cancer through regulation of miR-218-5p/HS3ST3B1, which is expected to serve as a new therapeutic target for bladder cancer.

Impact of perspective-taking and empathy on HIV-related stigma among college students in Guilin / 中国学校卫生

Objective@#To investigate the current status of HIV-related stigma among college students in Guilin,and to explore the impact of perspective-taking and empathy on HIV-related stigma among college students.@*Methods@#The stratified cluster sampling method was used to select college students from 4 universities in Guilin city. Stratified randomization was used to assign all subjects into a control group (410) and an experimental group (396) for randomized controlled trials,and the HIV-related Stigma Questionnaire and the Basic Empathy Scale were used before and after the intervention.@*Results@#Before the intervention of perspective-taking,there were no statistically significant differences between two groups in subscale scores and total scores of HIV-related stigma (t=0.80，0.35，-0.62，-0.10，P>0.05); However, signiticant differences in subscale scores and total score in HIV-related stigma were found after intervention (t=3.53，2.21，2.30，3.98，P<0.05). There was no statistically singnificant in the scores of all dimensions of empathy level and the total score before the intervention (t=0.10,-0.27,-0.08,P>0.05), dimensional score and total score in empathy were statistically significant after intervention (t=-2.15，-3.06，P<0.05). Empathy played an intermediary role of 14.08% between opinion selection and HIV stigma.@*Conclusion@#HIV-related stigma exists among college students in Guilin,and perspective-taking intervention effectively reduces its AIDS stigma. Empathy plays an intermediary role between them.

Effects of inflammatory responses, apoptosis, and STAT3/NF-κB- and Nrf2-mediated oxidative stress on benign prostatic hyperplasia induced by a high-fat diet.

This study determined whether or not benign prostatic hyperplasia (BPH) induced by a high-fat diet (HFD) is involved in inflammatory responses, apoptosis, and the signal transducer and activator of transcription (STAT3)/nuclear factor-kappa B (NF-κB)- and nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress pathways. Forty rats were divided into four groups: control; HFD; testosterone; and HFD+testosterone. Hematoxylin and eosin (HE) staining was used to assess histologic changes. An enzyme-linked immunosorbent assay and Western blot analysis were used to detect levels of related proteins. Compared with the control group, the prostate levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), transforming growth factor-ß1 (TGF-ß1), and monocyte chemotactic protein-1 (MCP-1) were significantly increased, while the levels of glutathione peroxidase (GSH-Px), glutathione reductase (GR), glutathione (GSH), and superoxide dismutase (SOD) were decreased. The TNF-κB, Bcl-2, and caspase-3 levels were increased, while the Bax level was markedly decreased. The cytoplasmic expression of STAT3 and NF-κB was increased, while the nuclear expression of Nrf2 was markedly decreased compared with the control group. In summary, our results demonstrated that a long-term HFD might cause changes in inflammatory responses, apoptosis, and oxidative stress, thus contributing to prostatic hyperplasia. The underlying mechanisms might be related to the STAT3/NF-κB- and Nrf2-mediated oxidative stress pathway.

Long Non-coding RNA DLEU1 Promotes Cell Proliferation, Invasion, and Confers Cisplatin Resistance in Bladder Cancer by Regulating the miR-99b/HS3ST3B1 Axis.

Although accumulating evidence has shown the important function of long non-coding RNAs (lncRNAs) in tumor progression and chemotherapy resistance, the role of lncRNA DLEU1 in regulating proliferation, invasion, and chemoresistance of bladder cancer (BCA) cells remains largely unknown. Here, we found that DLEU1 was upregulated in BLCA tissues and BCA patients with high DLEU1 expression exhibited a shorter survival time. Furthermore, mechanistic analysis and functional assays validated that DLEU1 induced cell proliferation, invasion, and cisplatin resistance of BCA cells by de-repressing the expression of HS3ST3B1 through sponging miR-99b. Low miR-99b and high HS3ST3B1 levels were correlated with worse prognosis in patients with BCA. Ectopic expression of HS3ST3B1 or inhibition of miR-99b reversed DLEU1 knockdown-mediated suppression of cell proliferation, invasion, and cisplatin resistance. Thus, our study revealed a novel role for the DLEU1/miR-99b/HS3ST3B1 axis in regulating proliferation, invasion, and cisplatin resistance of BCA cells.

Polarized M2c macrophages have a promoting effect on the epithelial-to-mesenchymal transition of human renal tubular epithelial cells.

This study planned to explore the effects of M2c macrophages on epithelial-to-mesenchymal transition (EMT) of human renal proximal tubular epithelial cells (HK-2). Human monocytic leukaemia cells were induced by TPA and IL-10 to differentiate M2c macrophages. Subsequently HK-2 cells were co-cultured with the M2c macrophages in Transwell chamber. After 48 h of co-culturing the HK-2 cells were detected in the mRNA and protein expression of E-cadherin, α-SMA and vimentin with RT-PCR, immunofluorescence and Western blot respectively. Besides, the migration ability of the HK-2 cells was estimated with Transwell migration assay. ANOVA was used to compare the difference between groups and Student's t-test to conduct multiple comparisons of two groups. P < 0.05 was considered statistically significant. The results showed that the mRNA and protein expression of α-SMA and vimentin of the HK-2 cells were increased but the E-cadherin decreased significantly after 48 h co-culturing with the M2c macrophages (P < 0.05 or P < 0.01). And the migration ability of HK-2 cells were also increased significantly (P < 0.05). It may be concluded that polarized M2c macrophages may have a promoting effect on the EMT of HK-2 cells.

Rab11 Functions as an Oncoprotein via Nuclear Factor kappa B (NF-κB) Signaling Pathway in Human Bladder Carcinoma.

BACKGROUND Elevated expression of Rab11 has been reported in different human cancers, including human bladder carcinoma. This study, we investigated the biological effects and mechanism of Rab11 overexpression in human bladder carcinoma for the first time. MATERIAL AND METHODS Rab11 expression in bladder cancer tissues was detected using immunohistochemistry and Western blot analysis. Then, Rab11 expression was inhibited in T24 cells and it was overexpressed in BIU-87 cells. The effects of Rab11 perturbations on cell growth rate and invasion were analyzed by CCK8, cell cycle assay, and matrix gel invasion assay. MMP-9, cyclin E, and cyclin D1 levels were studied using Western blot and qPCR. NF-κB activity was studied by luciferase assay. RESULTS High expression of Rab11 was detected in 41.5% (66/159) of tumor specimens. We found a significant correlation between high Rab11 expression and depth of tumor invasion (P=0.004). Rab11 overexpression was observed to promote the growth rate and invasiveness of cancer cells through upregulation of MMP9, cyclin E, and cyclin D1 levels. Rab11 overexpression further elevated NF-κB reporter activity and enhanced p-IκB expression. Use of BAY 11-7082, a noted NF-κB inhibitor, partially abolished overexpression of MMP9 and cyclin D1 by Rab11. CONCLUSIONS Our research proved that high Rab11 expression enhances cellular multiplication and invasiveness of bladder cancer, possibly by regulating the NF-κB signaling pathway.

Therapeutic Effects of FK506 on IgA Nephropathy Rat.

BACKGROUND/AIMS: FK506 is an immunosuppressive drug and a calcineurin inhibitor that has been widely used in kidney disease in recent years. FK506 shows a wide range of biological and pharmaceutical effects; however, the mechanism of its anti- proliferative effect has not been well elucidated. An IgA nephropathy (IgAN) model was used to generate a mesangial cell proliferation model. This study aims to examine the effect of FK506 on IgAN rats and the underlying mechanisms. METHODS: Hematuria, proteinuria and renal function were measured. To observe the pathological conditions, we performed HE (hematoxylin - eosin) and PAS (periodic acid - schiff) staining. Transcription and protein expression levels were detected by qRT - PCR (quantitative real-time polymerase chain reaction) and Wb (western blotting). The location and semi-quantitative expression levels of TRPCs, CaN (Calcineurin) and α-SMA were examined by IHC (Immunohistochemical staining). RESULTS: We found that FK506 could improve hematuria, proteinuria and renal function, especially in the HF (high-dose FK506) groups. Renal pathological changes were ameliorated in the treatment groups. FK506 could significantly decrease TRPCs, CaN, phosphorylation of ERK1/2 and α-SMA expression. CONCLUSION: Taken together, these results suggest that the therapeutic effect of FK506 on IgAN might be partially associated with the down-regulated expression of TRPC channels, CaN and phosphorylation of ERK1/2.

Association of Megsin Gene Variants With IgA Nephropathy in Northwest Chinese Population: A STROBE-Compliant Observational Study.

Megsin is a mesangial cell-predominant gene that encodes a serpin family protein which is expressed in the renal mesangium. Overexpression of megsin has been observed in the glomeruli of patients with IgA nephropathy (IgAN). The aim of this study was to evaluate the association of megsin polymorphisms (rs1055901 and rs1055902) with IgAN in a Chinese population.We examined 351 patients with histologically proven IgAN and compared them with 310 age, sex, and ethnicity-matched healthy subjects. Two single nucleotide polymorphisms (SNPs) in megsin were genotyped by Sequenom MassARRAY. SPSS 18.0 was used for statistical analyses, and SNP Stats to test for associations between these polymorphisms and IgAN risk. Odds ratios with 95% confidence intervals were used to assess the relationships.We found that rs1055901 and rs1055902 SNPs were not correlated with susceptibility to IgAN in Northwest Chinese population. Analyses of the relationship between genotypes and clinical variables indicated that in patients with IgAN, rs1055901 was associated with 24-hour proteinuria, an increase in blood pressure, and Lee's grade (P = 0.04, 0.02, and 0.04, respectively), and rs1055902 was associated with 24-hour proteinuria and Lee's grade (P = 0.03 and 0.01, respectively). However, the results showed no association between these gene variants and sex of the patients.These results indicate that megsin gene variants may play a role in the severity, development, and/or progression of IgAN in Northwest Chinese population.

Lack of Association Between Polymorphisms in AGT and ATR1 and IgA Nephropathy in a Chinese Population.

OBJECTIVE: The mechanism of immunoglobulin A nephropathy (IgAN) remains unclear. Genetic factors may be associated with the risk of IgAN. This study aims to identify the possible association of M268T (rs699) in the Angiotensinogen (AGT) gene and A1166C (rs5186) in the Angiotensin II receptor type 1 (ATR1) gene with IgAN risk. METHODS: Study subjects included 351 patients with IgAN and 310 controls from the Chinese population. The tag SNPs (tSNPs) were genotyped by Sequenom MassARRAY RS1000. Statistical analysis of the association between tSNPs and IgAN was performed using the χ(2) test and SNPStats software. RESULTS: The AGT (M268T) genotypes were distributed in IgAN as CC 61.9%, CT 34.8%, and TT 3.2%, while in controls CC 64.1%, CT 31.3%, and TT 4.6%. Distribution of ATR1 (A1166C) was AA 87.7%, CA 12.3%, and CC 0%, while in controls AA 87.2%, CA 12%, and CC 0.8%. We further analyzed tSNPs under different inheritance models and found that there were no significant differences in the genotypes and allele frequencies of rs699 and rs5186 between two groups (p > 0.05). We also analyzed tSNPs based on the rate of pressure, proteinuria and Lee's classification, and no significant differences were found in the models (p > 0.05). CONCLUSION: rs699 in the AGT gene and rs5186 in the ATR1 gene were not associated with the risk and clinical outcomes of IgAN.

[The impact of ambient particulate matter (PM10) on the population mortality for cerebrovascular diseases-a case-crossover study].

OBJECTIVE: To analyze the association between the concentration of ambient inhalable particulate matter (PM10) and population mortality for cerebrovascular diseases and to explore the impact of PM10 on cerebrovascular diseases. METHODS: Data including meteorological factors, air pollutants (NO2, SO2 and PM10) and cerebrovascular disease mortality in one district of Beijing from 2004 to 2008 were collected and both symmetric bidirectional case-crossover design and conditional logistic regression model were used to analyze the associations among them. RESULTS: After adjusting the influence of meteorological factors as daily average temperature and relative humidity, the single pollutant model showed that there was no significant lag effect. In the multi-pollutant model, the effect of the every 105.43 µg/m(3) increase of ambient PM10 had a larger impact on the daily death of the cerebrovascular diseases with statistically significant difference (P < 0.05). The effect of ambient PM10 pollution on daily death of cerebrovascular diseases was significant for females, 65 year-olds and in winter season. CONCLUSION: Our data showed that elevated levels of ambient PM10 was positively associated with the increase of cerebrovascular disease mortality. The elevated levels of ambient PM10 could lead to the increase of the daily mortality on cerebrovascular diseases for females, elderly who were 65 or older and in winter seasons.

[Association between ambient PM10/PM2.5 levels and population mortality of circulatory diseases: a case-crossover study in Beijing].

OBJECTIVE: To explore the association between levels of ambient particulate matters (PM10 and PM2.5) and population mortality of circulatory diseases (ICD10: I00~I99) in Beijing. METHODS: The daily data of ambient PM2.5 levels were monitored by the research team in Peking University from Jan. 1, 2007 to Dec. 31, 2008, and the corresponding meteorological and other air quality data (PM10, SO2 and NO2) were collected from National Meteorological Information Center (NMIC) of China and Beijing Environmental Monitoring Center. The data of daily death for the circulatory diseases were collected from the local center for Disease Control and Prevention of Haidian District in Beijing. The symmetric bidirectional case-crossover design and conditional logistic regression model were used for the data analysis. The cases were stratified by gender, age and seasons. The lagged effect was analyzed and the related confounders from meteorological factors and other air pollutants were adjusted. RESULTS: For a 10 µg/m(3) increase of the ambient concentration of PM2.5, the corresponding increase of daily mortality of the circulatory diseases, cardiovascular diseases and cerebrovascular diseases was 0.78% (95% CI: 0.07% to 1.49%), 0.85% (95% CI: -0.28% to 1.99%), and 0.75% (95% CI: -0.17% to 1.68%), respectively, for a 10 µg/m(3) increase of the ambient concentration of PM10, the corresponding increase of daily mortality of the circulatory diseases, cardiovascular diseases and cerebrovascular diseases was 0.36% (95% CI: -0.07% to 0.78%), 0.63% (95% CI: -0.02% to 1.28%), and 0.33% (95% CI: -0.26% to 0.92%),respectively. The significant positive associations were observed statistically between PM2.5 and the circulatory diseases (P<0.05). The association between ambient PMs and the population mortality was stronger in "warm season (April to September)" than in "cool season (October to the next March)" in Beijing (P<0.05). CONCLUSION: The elevated levels of ambient PM2.5 and PM10 were positively associated with the increase of the population mortality of the circulatory diseases, and the association is stronger in warm season, and the adverse effect of PM2.5 is greater than that of PM10.

[Relationship between daily mean temperature and emergency department visits for respiratory diseases: a time-series analysis].

OBJECTIVE: To quantitatively evaluate the influences of daily mean air temperature (DMT) on Emergency Department Visits (EDVs) for the respiratory diseases. METHODS: The EDV data from medical records for respiratory diseases in Peking University Third Hospital between January 2004 and June 2009 were collected. The data of the air pollutants (SO(2), NO(2) and PM(10)) and meteorological factors at the same time periods were also collected from the local authorities of Beijing. Time-series analysis and generalized additive models (GAM) were used to explore the exposurrre-response relationship between DMT and EDVs for respiratory diseases. RESULTS: A total of 35 073 patients [males 14 707(41.93%,14 707/35 073), females 19 122(54.52%,19 122/35 073) and gender missing 1 244(3.55%, 1 244/35 073)] EDVs for respiratory diseases were included. The relationship between DMT and EDVs for the respiratory diseases was mainly of "V" shape, the optimum temperature(OT) was about 4 °C and the effect of DMT was significant with a 0-3 day lag structure for most of the models. When DMT≤OT, each 1°C decrease in DMT corresponded to 3.75% (95% CI of RR: 0.938 3-0.965 3), 3.10% (95% CI of RR:0.949 2-0.989 1), 4.09% (95% CI of RR:0.940 7-0.977 8) increase of EDVs for the overall, male, and female, respectively. When DMT>OT, the value caused by each increase in 1°C in DMT was 1.54% (95% CI of RR:1.006 6-1.024 3), 1.80% (95% CI of RR:1.005 3-1.030 9), and 1.51 (95% CI of RR:1.003 2- 1.027 2), respectively. The effect was statistically significant within the 0-3 day lag. When DMT≤OT, the effect was stronger for the older people, while the effect was strongest for the 45-59 years old people. CONCLUSION: The relationship between DMT and EDVs for respiratory diseases is mainly of "V" type, with an optimum temperature of 4 °C.Both DMT decrease when DMT≤OT and increase when DMT>OT correspond to different increase of EDVs for respiratory diseases. Low DMT has stronger effect than high DMT. Different age group and gender have different effects.

[Theanine, EGCG and caffeine determinated by HPLC].

OBJECTIVE: A high-performance liquid chromatography (HPLC) method was developed for the determination of theanine in puer tea without derivatization and HPLC for EGCG and caffeine with ingredient elution system was put forward. METHODS: The theanine in the tea was extracted with water. The EGCG and caffeine was extracted with water: ethanol (3:7) by ultrasonic oscillation. After centrifugation, the extract was analyzed by HPLC-PDAD with a C18column and at the flow rate 1 ml/min. The theanine was determinated with 5 mmol/L SDS-acetonitrile mobile phase system (72:28), and both EGCG and caffeine with 0.05 mmol/L KH2PO4-methonal mobile phase system (80:20). RESULTS: The calibration of three ingredients was in good linearity. The recovery range is 85%-110%. The RSD is less than 10%. CONCLUSION: The method is accurate and stable.