[Correlation between the increase in corneal higher-order aberrations and the control of children's myopic anisometropia after wearing orthokeratology lenses]

Objective: To explore the interocular differences in both the increase of corneal higher-order aberrations (HOAs) and axial length elongation, and the correlation between them after orthokeratology lens (OK lens) wear in children with myopic anisometropia. Methods: It was a prospective cohort study. From 2018 to 2019, 31 children with myopic anisometropia who were fitted with OK lenses initially in the Department of Ophthalmology of Peking University Third Hospital were enrolled, including 15 males (30 eyes) and 16 females (32 eyes). The age was (10.7±1.4) years. Before (baseline) and 12 months after wearing OK lenses, corneal aberrations, corneal relative refractive power (corneal RRP, the difference between peripheral corneal refraction and central corneal refraction) and axial length were measured using the Sirius combining a corneal topographer and a tomographer and an IOL-Master intraocular lens biometer in two eyes. Interocular differences in corneal aberrations, corneal RRP and axial length were analyzed by the paired t test and Wilcoxon rank sum test. The Pearson and Spearman correlation analyses were used to explore the correlation between the increase in corneal HOAs, corneal RRP and axial length elongation. Results: At 12 months after wearing OK lenses, 6 children were lost for follow-up, and the data of the remaining 25 children (50 eyes) were evaluated. With 3.0- and 6.0-mm measuring zones of the total cornea and the anterior surface, the increases in total corneal HOAs, coma, spherical aberration of higher myopic eyes were significantly more than fellow lower myopic eyes (all P<0.05). The corneal RRP with 2.0-mm and 2.5-mm radius in the upper cornea and 2.5-mm radius in the inferior cornea of higher myopic eyes were more than fellow lower myopic eyes (t=-2.06, -2.07, -2.42; P=0.05, 0.049, 0.023), but there was no significant interocular difference in corneal RRP in the horizontal meridian direction of the cornea (both the nasal and temporal sides of the cornea) (both P>0.05). The axial length elongation in higher myopic eyes was 0.14 (0.08, 0.20) mm, which was significantly less than that in the contralateral eyes [0.18 (0.14, 0.35) mm] (Z =-3.21, P= 0.001). The interocular difference in axial length decreased from 0.40 (0.34, 0.54) mm at baseline to 0.33 (0.24, 0.54) mm (Z =-3.21, P = 0.001). The increases in HOAs, coma and spherical aberration of the anterior corneal surface with 3.0-mm measuring zone and the increase in coma of the anterior corneal surface with 6.0-mm measuring zone were all negatively correlated with axial length elongation (r=-0.493, -0.606, -0.500, -0.307; P<0.05). But the corneal RRP had no significant correlation with axial length elongation (r=-0.092, -0.104, -0.230, -0.061; P>0.05). Conclusion: After 12 months of OK lens wear, interocular difference in axial length reduced significantly in children with myopic anisometropia, which was related to the larger increase in corneal HOAs of higher myopic eyes than fellow lower myopic eyes, especially coma.

[Evaluation of safety of two inactivated COVID-19 vaccines in a large-scale emergency use]

Objective: To evaluate the safety of two inactivated COVID-19 vaccines in a large-scale emergency use. Methods: Based on the "Vaccination Information Collection System", the incidence data of adverse reactions in the population vaccinated with the inactivated COVID-19 vaccines developed by Beijing Institute of Biological Products Co., Ltd and Wuhan Institute of Biological Products Co., Ltd, respectively, in emergency use were collected, and the relevant information were analyzed with descriptive epidemiological and statistical methods. Results: By December 1, 2020, the vaccination information of 519 543 individuals had been collected. The overall incidence rate of adverse reactions was 1.06%, the incidence rate of systemic adverse reactions was 0.69% and the incidence rate of local adverse reactions was 0.37%. The main systemic adverse reactions included fatigue, headache, fever, cough and loss of appetite with the incidence rates of 0.21%, 0.14%, 0.06%, 0.05% and 0.05%, respectively; the main local adverse reactions were injection site pain and injection site swelling with the incidence rates of 0.24% and 0.05%, respectively. Conclusion: The two inactivated COVID-19 vaccines by Beijing Institute of Biological Products Co., Ltd and Wuhan Institute of Biological Products Co., Ltd showed that in the large-scale emergency use, the incidence rate of general reactions was low and no serious adverse reactions were observed after the vaccinations, demonstrating that the vaccines have good safety.

Development and Evaluation of the Rapid and Sensitive RPA Assays for Specific Detection of Salmonella spp. in Food Samples

Salmonella spp. is among the main foodborne pathogens which cause serious foodborne diseases. An isothermal real-time recombinase polymerase amplification (RPA) and lateral flow strip detection (LFS RPA) were used to detect Salmonella spp. targeting the conserved sequence of invasion protein A (invA). The Real-time RPA was performed in a portable florescence scanner at 39°C for 20 min. The LFS RPA was performed in an incubator block at 39°C for 15 min, under the same condition that the amplifications could be inspected by the naked eyes on the LFS within 5 min. The detection limit of Salmonella spp. DNA using real-time RPA was 1.1 × 10¹ fg, which was the same with real-time PCR but 10 times higher than that of LFS RPA assay. Moreover, the practicality of discovering Salmonella spp. was validated with artificially contaminated lamb, chicken, and broccoli samples. The analyzing time dropped from 60 min to proximately 5–12 min on the basis of the real-time and LFS RPA assays compared with the real-time PCR assay. Real-time and LFS RPA assays’ results were equally reliable. There was no cross-reactivity with other pathogens in both assays. In addition, the assays had good stability. All of these helped to show that the developed RPA assays were simple, rapid, sensitive, credible, and could be a potential point-of-need (PON) test required mere resources.

[Preoperative Lymphocyte-to-monocyte Ratio Predicts Prognosis in Patients with Stage T1 Non-muscle Invasive Bladder Cancer]

Objective To investigate the clinical value of preoperative lymphocyte-to-monocyte ratio(LMR)in evaluating the prognosis of patients with stage T1 non-muscle invasive bladder cancer(NMIBC).Methods A total of 215 patients with stage T1 NMIBC who underwent transurethral resection of bladder tumor were enrolled.Clinical data were collected.Patients were followed up and their disease-free survival(DFS)and overall survival(OS)were recorded.The receiver operating characteristic(ROC)curve of preoperative LMR in detecting patient prognosis was used to determine the optimal cut-off value for LMR.Patients were divided into low LMR group(LMR <3.86,n=77)and high LMR group(LMR ≥ 3.86,n=138).Kaplan-Meier survival curves were explored to compare cumulative DFS and OS rates in patients with different LMR levels,and COX proportional hazards regression model was used to analyze factors associated with DFS and OS.Results All these 215 patients with T1 stage NMIBC were followed up for 2-92 months,and the DFS rate was 59.07% and OS rate was 65.12%.Kaplan-Meier curves showed that the cumulative DFS rate(χ ²=4.784,P=0.029)and cumulative OS rate(χ ²=7.146, P=0.008)in the low LMR group were significantly lower than those in the high LMR group.Tumor size ≥ 3 cm(HR=1.398,95% CI:1.042-1.875,P=0.025),pathological grade G3(HR=1.266,95% CI:1.026-1.563,P=0.028),and LMR ≥ 3.86(HR=2.347,95% CI:1.080-5.101,P=0.031)were independent factors associated with DFS in patients with stage T₁ NMIBC.In addition,tumor size ≥ 3 cm(HR=1.228,95% CI:1.015-1.484,P=0.034),pathological grade G3(HR=1.366,95% CI:1.017-1.834,P=0.038),and LMR<3.86(HR=2.008,95% CI:1.052-3.832,P=0.035)were independent factors associated with OS in patients with T1 stage NMIBC. Conclusion Preoperative LMR is an independent factor associated with patients' prognosis in T1 stage NIMBC.Patients with low LMR tend to have higher risk of NMIBC progression and death.

[Clinical significance and cost-benefit analysis of serum calcitonin assay in diagnosis and treatment of medullary thyroid carcinoma]

Objective: To study the clinical significance of serum calcitonin in the diagnosis and treatment of medullary thyroid carcinoma and to analyze its cost-benefit. Methods: One hundred and forty one patients with medullary thyroid carcinoma who undertook calcitonin test and frozen pathological examination were enrolled in this study from Oct 2012 to Mar 2018. Using the method of χ(2) test, the positive rate of calcitonin test and frozen pathological examination in diagnosis of medullary thyroid carcinoma(MTC) were compared. Firstly, we compared the correct checkout cost of calcitonin test and that of frozen pathological examination (total number of patients×cost of examination/the correctly detected number of patients) . Secondly, we calculated whether calcitonin test help patients save money(average cost of treatment in hospital for MTC×number of patients who were evaluated to be candidate for surgery-cost of calcitonin test×total number of patients)/total number of patients. Results: 139 patients were positive in calcitonin test among 141 patients, and the positive rate was 98.58%. 91 patients were positive in frozen pathological examination, and the positive rate was 64.54% (χ(2)=97.821, P<0.000 1) . Cost-benefit analysis showed that the correct checkout cost of calcitonin test and frozen pathological examination were 71.01 yuan and 426.10 yuan, also,1 371 938.64 yuan could be saved totally and 9 730.06 yuan could be saved per patient because of calcitonin test. Conclusion: Serum calcitonin test had a significant effect on the diagnosis and treatment of medullary thyroid carcinoma and was economical and practical.

Development and evaluation of a rapid and sensitive RPA assay for specific detection of Vibrio parahaemolyticus in seafood

Background

Vibrio parahaemolyticus (V. parahaemolyticus) is a leading cause of food poisoning and is of great importance to public health due to the frequency and seriousness of the diseases. The simple, timely and efficient detection of this pathogen is a major concern worldwide. In this study, we established a simple and rapid method based on recombinase polymerase amplification (RPA) for the determination of V. parahaemolyticus. According to the gyrB gene sequences of V. parahaemolyticus available in GenBank, specific primers and an exo probe were designed for establishing real-time recombinase polymerase amplification (real-time RPA).

Results

The real-time RPA reaction was performed successfully at 38 °C, and results were obtained within 20 min. The method only detected V. parahaemolyticus and did not show cross-reaction with other bacteria, exhibiting a high level of specificity. The study showed that the detection limit (LOD) of real-time RPA was 1.02 × 10² copies/reaction. For artificially contaminated samples with different bacteria concentrations, V. parahaemolyticus could be detected within 5–12 min by real-time RPA in oyster sauce, codfish and sleeve-fish at concentrations as low as 4 CFU/25 g, 1 CFU/25 g and 7 CFU/25 g, respectively, after enrichment for 6 h, but were detected in a minimum of 35 min by real-time PCR (Ct values between 27 and 32).

Conclusion

This study describes a simple, rapid, and reliable method for the detection of V. parahaemolyticus, which could potentially be applied in the research laboratory and disease diagnosis.

Real-time recombinase polymerase amplification assay for the rapid and sensitive detection of Campylobacter jejuni in food samples

Campylobacter jejuni (C. jejuni), a foodborne pathogen, is a major contributor to human bacterial gastroenteritis worldwide and detrimental to public health. It is crucial for initiating appropriate outbreak control strategies to rapidly detect C. jejuni. As a novel isothermal gene amplification technique, recombinase polymerase amplification (RPA) has been developed for the molecular detection of diverse pathogens. In this study, we developed a real-time RPA assay so as to achieve the rapid and efficient detection of C. jejuni by targeting the hipO gene. The specificity and senstivity of real-time RPA was validated and the practical applicability of the method for the detection of C. jejuni in artificially contaminated milk and chicken breast samples was proved by comparing their reaction time, sensitivity, and efficacy with those of real-time PCR and culture-based methods. Based on the real-time RPA assay, analysis time was reduced to approximately 13 mins from 60 mins and the results were as reliable as those of the real-time PCR assay. Taken together, in terms of the detection of C. jejuni, the real-time RPA method was simple, rapid, sensitive, and reliable.

[Short-term outcomes of minimally invasive Sweet esophagectomy for Siewert type Ⅱ esophagogastric junction adenocarcinoma]

Objective: To describe the technique for minimally invasive Sweet esophagectomy and to evaluate the feasibility, safety and the short-term clinical outcomes of this approach in the treatment of Siewert type Ⅱ esophagogastric junction adenocarcinoma. Methods: The clinical data of 122 patients with Siewert type Ⅱ esophagogastric junction adenocarcinoma who received Sweet esophagectomy between October 2013 and June 2015 in Department of Thoracic Surgery, Anhui Provincial Hospital Affiliated with Anhui Medical University was analyzed retrospectively. The study group consisted of 87 men and 35 women, and the ages ranged from 48 to 78 years (median: 67 years). Of those 122 patients, 47 underwent minimally invasive approach and 75 underwent open left transthoracic sweet esophagectomy. This study included 16 stage Ⅰa patients, 35 stage Ⅰb patients, 32 stage Ⅱa patients, 28 stage Ⅱb patients, and 11 stage Ⅲa patients. The clinicopathologic factors, operational factors and postoperative complications of the two groups were compared by t test and χ² test. Results: The two groups were similar in terms of gender, age, American Society of Anesthesiologists grade, preoperative staging and incidence of comorbidities (P>0.05). The minimally invasive approach was associated with significant increase in the number of total lymph nodes dissected or the stations of the total lymph nodes dissected (18.1±2.7 vs. 15.0±2.5, t= 6.612, P=0.001; 8.9±1.1 vs. 6.7±1.2, t=9.960, P=0.003), significant decrease in surgical blood loss ((88±32) ml vs. (120±34) ml, t=5.052, P=0.001), chest tube duration ((8±4) d vs. (10±4) d, t=3.110, P=0.002) and postoperative stay ((9±5) d vs. (12±4) d, t=3.167, P=0.002) relative to the open approach. The postoperative in-hospital mortality and total morbidity did not differ between the two groups (P>0.05). The minimally invasive approach was associated with significantly fewer respiratory complications than the open approach (8.5% vs. 22.7%, χ²=4.063, P=0.044). Conclusion: Minimally invasive technique for Siewert type Ⅱ esophagogastric junction adenocarcinoma can be safely and effectively performed for intrathoracic anastomosis with favorable early outcomes.

Development and characterization of novel microsatellite markers in the rock bream fish Oplegnathus fasciatus

The rock bream fish Oplegnathus fasciatus is one of the most popular aquaculture species in China. In the present study, 15 novel polymorphic microsatellite loci were isolated and characterized from a wild population of O. fasciatus from the Zhoushan coast of China. The number of alleles per polymorphic locus ranged from 4 to 9 in a sample of 30 individuals. Observed and expected heterozygosities per locus varied from 0.267 to 0.767 and from 0.395 to 0.859, respectively. Eleven of the 15 microsatellite loci conformed to Hardy-Weinberg equilibrium. No significant linkage disequilibrium between pairs of loci was detected. The present microsatellite markers could provide a useful tool for the genetic analyses of O. fasciatus.

Therapeutic Effects of Intravenous Infusion of Hyperoxygenated Solution on Acute Haemorrhagic Shock in Rabbits

Tissue anoxia is the main mechanism of the shock reaction. Here, the effect of hyperoxygenated solution (HOS) on acute haemorrhagic shock was studied in rabbits. At 60 min after shock, rabbits were infused intravenously with hyperoxygenated solution at 10 (HOS1 group) or 20 ml/kg (HOS2 group) or with Ringer's solution at 10 ml/kg (RS group). Compared with values before shock, values after shock were lower for mean arterial pressure (MAP), more negative for base excess (BE) and higher for blood lactate (BL) and blood viscosity. After infusion, MAP declined more slowly in the HOS1 and HOS2 groups than in the RS group. At 30 and 60 min after infusion, arterial partial pressure of oxygen (PaO2) and oxygen saturation (SaO2) were higher and BE was less negative in the HOS1 and HOS2 groups than in the RS group, BL was lower in the HOS1 and HOS2 groups than in the RS group, and PaO2 and SaO2 were higher in the HOS2 group than in the HOS1 group. It was concluded that HOS infusion can rectify changes in vital signs more effectively than Ringer's solution after acute haemorrhagic shock in rabbits.

The protective effects of melatonin from oxidative damage induced by amyloid beta-peptide 25-35 in middle-aged rats

This work investigated the ability of melatonin to prevent oxidative damage in brain tissue induced by injection of beta-amyloid peptide 25-35 (Abeta25-35) in middle-aged rats. The Morris water maze was used to evaluate the cognitive function of the rats. Thiobarbituric acid-reactive substances and antioxidative enzymes (superoxide dismutase and glutathione peroxidase) activities were measured. It was found that injection of (Abeta25-35) (20 microg) into the rat hippocampus caused an increase in the latency (the time to find the platform), the total swimming distance to the platform, and the starting angles in (Abeta25-35)-treated rats. Furthermore, a significant rise in lipid peroxidation and decrease in antioxidative enzyme activities in brain tissue were found. Melatonin (0.1, 1, and 10 mg/kg, i.g. x 10 days) improved the spatial resolution of amnesic rats in the Morris water maze test. Meanwhile, melatonin antagonized the lipid peroxidation in both the mitochondria (P < 0.01) at the doses of 0.1, 1.0, and 10 mg/kg and in the cytoplasm at the doses of 0.1 and 1.0 mg/kg. Also in the amnesic rats, melatonin (0.1, 1.0, and 10 mg/kg. i.g. x 10 days) stimulated the antioxidative enzyme activities. The results show that melatonin effectively reduced lipid peroxidation and enhanced the antioxidative enzyme activities in Abeta(25-35)-treated rats, which may contribute to the improvement of rats' learning and memory impaired by Abeta(25-35).

Chiral derivatization reagents for drug enantioseparation by high-performance liquid chromatography based upon pre-column derivatization and formation of diastereomers: enantioselectivity and related structure

Structures and related enantioselectivities of the respective chiral derivatization reagents (CDRs) for drug enantioseparation by high-performance chromatography based upon pre-column derivatization and diastereomeric formation are reviewed. The elution order of diastereomers caused reaction of some CDRs with enantiomeric amino acids and carboxylic acids. The development of new CDRs available for indirect HPLC methods is also discussed. (c) 2001 John Wiley & Sons, Ltd.

[Experimental study on preventive and therapeutic effect of bushen huoxue recipe on autoimmune premature ovarian failure model]

OBJECTIVE

To investigate the mechanisms of Bushen Huoxue Recipe (BSHXR), a Chinese herbal medicinal preparation for tonifying Kidney and invigorating blood circulation, to prevent and treat autoimmune premature ovarian failure (POF) model.

METHODS

Female 8-10 weeks old BAL B/c mice were immunized by intracutaneously injecting porcine ovum zona pellucida (ZP), isolated by immuno-chromatography, in multiple points of two hind footpads to establish the POF model and treated with BSHXR started from early stage of immunization (prevented group) or after 3 times of injection (treated group). Changes in vaginal smears, serum estradiol (E2), antibody titer against ZP, response of splenic lymphocyte to ZP stimulation of different concentrations, and numbers of ovarian follicles and corpus luteum were analyzed.

RESULTS

Serum E2 level in the prevented and treated mice was all higher than that in the non-treated immunized model mice (the control group), P < 0.01 and P < 0.05 respectively. But the anti-ZP titer lowered significantly after BSHXR administration, as compared with that in the control group. Level of antibodies in the treated group was lower than that of the control, and it was also lower in the prevented group than that in the control. The histo-morphological examination showed that the developing follicles and corpus luteum after BSHXR medication in both prevented and treated group increased significantly as compared with that of the control group (P < 0.05 and P < 0.01 respectively). Splenic lymphocyte in the immunized model showed a higher antigen-specific proliferation reaction than that in non-immunized animal, and the reaction was ameliorated by BSHXR medication.

CONCLUSION

BSHXR could recover part of the ovarian function in POF mice mainly through inhibiting specific immune injury to revive the remnant follicles in ovary. The preventive effect of BSHXR was superior to the therapeutic effect of it.

Contributions of protein disulfide isomerase domains to its chaperone activity

Protein disulfide isomerase (PDI), a member of the thioredoxin (Trx) superfamily, consists of five consecutive domains, a-b-b'-a'-c. Domain combinations, AB, A'C, B'A'C and AB-C, and hybrids of PDI domains with Trx, Trx-C and Trx-B'A'C, have been constructed and expressed in Escherichia coli to examine the contributions of PDI domains to its enzyme and chaperone activities. All the combination and hybrid products are considerably less active than intact PDI in their enzyme activities. Recombinant products containing C, at low concentrations, inhibit the reactivation of lysozyme in HEPES buffer, while those without C do not. Only the intact PDI molecule and the hybrid molecule, Trx-B'A'C, but to a much lower level, show general chaperone activity in assisting the reactivation of denatured D-glyceraldehyde-3-phosphate dehydrogenase. It is suggested that all domains of PDI contribute to the binding of target protein for its chaperone activity.

The N-terminal sequence (residues 1-65) is essential for dimerization, activities, and peptide binding of Escherichia coli DsbC

Limited proteolysis of DsbC with trypsin resulted in a compact and stable C-terminal fragment (residues 66-216), fDsbC, which retains the active site sequence, -Cys(98)-Gly-Tyr-Cys(101)-, and shows only minor differences in conformation compared with that of the intact molecule. The pK(a) of active site thiol and the K(SS) with glutathione are very close to that of DsbC, respectively; however, fDsbC is inactive as an isomerase in catalyzing the formation of correct disulfide bonds in scrambled RNase A and denatured and reduced bovine pancreatic trypsin inhibitor and shows only 13% thiol-protein oxidoreductase activity (TPOR) of DsbC. In contrast to the dimeric DsbC, fDsbC exists as a monomer and has no chaperone activity in assisting the reactivation of denatured d-glyceraldehyde-3-phosphate dehydrogenase. The heterodimer of DsbC with the inactive DsbC carboxymethylated at both active site thiols shows about 50% TPOR activity of DsbC but no isomerase activity, indicating that the DsbC subunit in the heterodimer displays full TPOR activity but little, if any, isomerase activity. It is concluded that the N-terminal sequence (residues 1-65) is essential for dimer formation and chaperone activity of DsbC. The active sites in both subunits of the dimeric DsbC appear to be essential for its isomerase activity.

[Investigation and application of auto-circulative washing and sterilization cabinet for catheters]

The structure, working principle, and operation of a sterilizing cabinet with autocircle washing for catheters was introduced in this article, 100 catheters were tested. The result revealed that no incrustation, rusty spot or thrombus existed after washing, and that hepatitis virus had been killed thoroughly. This cabinet can save the operator's time, make the operation easy, and prevent cross infection.

[Experimental study on cell cycle in rabbits' aortic smooth muscle cell culture in vitro with tongmai jiangzhi liquor]

The effects of Tongmai Jiangzhi Liquor (TMJZL) on the cell cycle kinetics in smooth muscle cell (SMCO of rabbits' midlayer of aortic wall was observed. It was showed that TMJZL could extend the time of cell culture, lower the percentage of SMC in G0/G1 phase and elevate the percentage of SMC in S phase gradually. The higher the concentration, the stronger the effect. The experiment showed that TMJZL had a marked inhibition of SMC of rabbits' midlayer of aortic wall cultured in vitro.

[Anti-free-radical damaging action of panaxadiol saponins and panaxatriol saponins on the myocardial contractibility of the isolated rat working heart]

Rats were free-radical-damaged by xanthine 6.4 mg.100g-1.d-1 and xanthine oxidase 0.1U.100g-1d-1 to cause significant decrease in the cardiac functional parameters. Panaxatriol saponins 10mg.100g-1.d-1 converted all the indices toward normal without exception. Panaxadiol saponins were more effective than panaxatriol saponins.

Effects of copper and selenium on electric parameters of cultured myocardial cells damaged by xanthine-xanthine oxidase

Addition of xanthine 0.42 mmol.L-1 and xanthine oxidase 5.3 nmol.L-1 (X-XO) to the culture medium increased the amplitude of ESR spectra of myocardial cells, demonstrating an increase in free radical contents; diminished the action potential parameters significantly and reduced the input impedances from 0.34 +/- 0.11 to 0.24 +/- 0.1 M omega, expressing a typical electrical appearance of membrane damage. Supplying Cu 62.5 ng.ml-1 and/or Se 173 ng.ml-1 to the medium brought all of the electric parameters and the free radical content of myocardial cells back to normal. The results indicate that both the two trace elements are able to scavenge free radicals, thus antagonizing X-XO, which induces damage to myocardial cells.

[Determination of lead in urine by differential potentiometric stripping analysis]

In the determination of lead in urine by differential potentiometric stripping analysis (DPSA) urine samples are acidified with hydrochloric acid to a total concentration equal to 0.2 mol/L without prior digestion with mineral acids. The sample is pre-electrolyzed at -1.2V (Vs SCE) for 80 seconds by glassy-carbon electrode coated with mercury. The lead concentrations are evaluated by means of standard addition. Detection limit of the method is 2ppb. The linear relationship occurs in the range of 0-150ppb. The relative standard deviations are 1.6% and the recovery of lead in urine samples is 89.5-110.0%. Compared with dithizone method, this method shows no significant difference in the results obtained.