Objective To establish a method for simultaneous determination of four high-molecular-weight thiol derivatives (TDs) in workplace air by gas chromatography. Methods The four kinds of vapor-phase macromolecular TDs (1-pentanethiol, 1-hexanethiol, 1-benzyl mercaptan, and n-octanethiol) in the workplace air were collected using the GDH-1 air sampling tubes, desorbed with anhydrous ethanol, separated on a DB-FFAP capillary column, and determined by flame ionization detector. Results The quantitation range of the four TDs was 0.30-207.37 mg/L, with the correlation coefficients greater than 0.999 00. The minimum detection mass concentrations and minimum quantitation mass concentrations were 0.18-0.32 and 0.60-1.05 mg/m³, respectively (both calculated based on the 1.5 L sample and 3.0 mL desorption solvent). The mean desorption efficiencies ranged from 87.07% to 103.59%. The within-run and between-run relative standard deviations were 1.92%-8.22% and 1.89%-8.45%, respectively. The samples can be stored at room temperature or 4 ℃ for three days and up to 7 days at -18 ℃. Conclusion This method is suitable for the simultaneous determination of four vapor-phase TDs in workplace air.

Objective To analyze differential metabolites (DMs) in the urine of workers with occupational nickel exposure using non-targeted metabolomics, and to screen differential metabolic pathways. Methods A total of 30 nickel exposed workers were selected as the exposure group, and 30 administrative staff from the same factory were selected as the control group using the judgment sampling method. Urine samples of the individuals from the two groups were collected. The ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry and non-targeted metabolomics were used to detect and identify metabolites. The differential metabolic profiles were compared between workers of the two groups, and key differential metabolic pathways and potential biomarkers were screened. The association of DMs and urinary nickel level were evaluated by Spearman correlation coefficients. The sensitivity and specificity of biomarkers were assessed by receiver operating characteristic (ROC) curve analysis. Results A total of 418 metabolites were identified in the urine of worker in the exposure and control groups. The result of principal component analysis and orthogonal partial least squares analysis showed that there were 128 DMs in the urine of workers in the exposure group compared with the control group. These DMs were mainly enriched in glutathione metabolism, carnitine synthesis, and amino acid and nucleotide metabolism pathways, including glycine and serine metabolism. The result of correlation analysis and ROC curve analysis revealed that 4-methylcatechol, 4-vinylphenol sulfate, 2-hydroxyphenylacetone sulfate, 2-dodecylbenzenesulfonic acid, and decylbenzenesulfonic acid could be the potential biomarkers for nickel exposure (all area under the ROC curve >0.800). Conclusion There were significant differences in the urinary metabolic profiles of workers with occupational nickel exposure. The five DMs including 4-methylcatechol, 4-vinylphenol sulfate, 2-hydroxyphenylacetone sulfate, 2-dodecylbenzenesulfonic acid, and decylbenzenesulfonic acid. These DMs could be potential biomarkers of occupational nickel exposure.

Biotoxins, which include bacterial, fungal, marine, plant, and animal toxins, are widespread in living and occupational environments, posing potential threats to human health. Rapid detection of biotoxins in blood is crucial for preventing health hazards and enabling timely disease diagnosis and treatment. Biosensors and immunoassay technologies have critical advantages in the rapid detection of biotoxins in blood. Common biosensors, such as surface plasmon resonance biosensors and fluorescent biosensors, enhance sensitivity and reduce detection limits through signal amplification. Common immunoassay methods, such as colloidal gold immunochromatography, fluorescence immunochromatography, and chemiluminescence immunoassay, improve detection efficacy and sensitivity through specific antibody-antigen binding and nanotechnology. However, current rapid detection technologies of bitoxins in blood face challenges such as matrix interference and insufficient specificity, and they fall short in high-throughput detection of multiple toxins simultaneously. Future developments should focus on improving sample pretreatment, innovating signal amplification methods, enhancing specificity on recognition of elements, and designing portable detection devices and high-throughput platforms for simultaneous toxin analysis. These advancements aim to improve the sensitivity and reliability of detection methods, providing more accurate and convenient solutions for biotoxin detection in blood.

Objective:To seek the optimal melanin-removal method for hematoxylin and eosin (HE) staining, immunohistochemistry and molecular detection.Methods:Thirty-eight paraffin tissue samples of malignant melanoma diagnosed at the Fujian Cancer Hospital, Fuzhou, China between January 2018 and March 2022 were collected and used to make a tissue microarray. Melanin in these cases was removed using warm hydrogen peroxide, double oxidation depigmentation, modified potassium permanganate-oxalic acid or trichloroisocyanuric acid, followed by HE staining. The cases were divided into two cohorts: one was subject to the one of the above four methods to remove melanin first, followed by immunohistochemistry (SOX-10, Ki-67, HMB45 and Melan A), while the other was subject to immunohistochemical staining first and then a melanin removal. Following that, seventeen melanin-rich paraffin tissue samples were collected and depigmented using the methods described above. DNA extraction was then done, followed by assessments of DNA content and quality. Moreover, the completeness of melanin removal, the effect on HE and immunohistochemical staining, and the quality of DNA were compared between the depigmented methods.Results:Regarding the effectiveness of melanin removal, the modified potassium permanganate-oxalic acid and the warm hydrogen peroxide methods were the most effective, and both showed residual melanin in only 5.26% (2/38) of the cases. The trichloroisocyanuric acid method showed residual melanin in 10.53% (4/38) of the cases. The worst was the double oxidation depigmentation method, which showed pigment residue in 15.79% (6/38) of the cases. For HE staining, the percentage of good staining with the warm hydrogen peroxide method was 92.11%, higher than the other three methods. For immunohistochemical staining, the mean staining scores of immunohistochemistry first followed by melanin removal with modified potassium permanganate-oxalic acid, double oxidation and trichloroisocyanuric acid were 20.84, 26.63 and 35.02, respectively. These immunohistochemical staining scores were higher than those of melanin removal first followed by immunohistochemistry (8.70, 15.41 and 21.22, respectively). The mean staining score of melanin removal by warm hydrogen peroxide method followed by immunohistochemistry was 33.57, superior to that of immunohistochemistry followed by the melanin removal (19.96). Moreover, the staining scores of HMB45, MelanA and Ki-67 with immunohistochemical staining followed by trichloroisocyanuric acid method were 36.45, 33.79, and 36.24, respectively, while the staining score of SOX10 with melanin removal by warm hydrogen peroxide followed by immunohistochemistry was 34.39. The DNA was significantly degraded by modified potassium permanganate-oxalic acid, double oxidation depigmentation and trichloroisocyanuric acid, whereas the mean concentration of DNA extracted after melanin removal by hydrogen peroxide method was 59.59 μg/L, substantially higher than that of DNA extracted without melanin removal (30.3 μg/L, P=0.001). The A260/ A280 of DNA extracted after melanin removal by hydrogen peroxide was between 1.8 and 2.0 in all cases, and the A260/ A230 was above 2.0 in sixteen cases, suggesting high purity of DNA. However, the DNA extracted without removing the melanin showed poor purity, with A260/ A280 below 1.8 in eight cases and A260/ A230 below 2.0 in sixteen cases. Conclusions:Warm hydrogen peroxide showed the least melanin residue, superior HE staining and a minimal effect on DNA purity/quality compared to the other three methods. It thus appears most suitable for PCR, NGS and other molecular detection. Melanin removal with trichloroisocyanuric acid after immunohistochemical staining has the least melanin residual, and thus could be the most convenient and efficient. However, it is noted that the efficacy of the same depigmentation method varies with different antibodies. Therefore, the optimal depigmentation method should be selected based on the specific markers of interest.

{L-End}Objective To establish a method for the simultaneous determination of dimethyltin (DMT), trimethyltin (TMT), diethyltin (DET), and triethyltin (TET) in human whole blood using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (ICP-MS). {L-End}Methods The 1.0 mL of blood was added with 4.0 mL 65% aqueous solution (containing 6% acetic acid), extracted and separated by C₄ column (150 mm×3 mm×3 μm) using a mobile phase of methanol and 4% acetic acid aqueous solution (containing 0.25 mmol/L tropolone) at a volume ratio of 35∶65, and detected by ICP-MS. {L-End}Results The linear range of DMT, TMT, DET, and TET was 30.60-550.80, 29.00-522.00, 46.10-829.80, and 34.05-612.90 μg/L, respectively. All correlation coefficients were 0.999. The detection limit of DMT, TMT, DET and TET was 21.40, 20.30, 32.27 and 23.80 μg/L, respectively. The recovery rate was 81.9%-104.9%. The within-run and between-run relative standard deviation was 1.6%-6.9% and 0.1%-10.0%, respectively. The samples can be stored at -20 ℃ and 4 ℃ for at least three days. {L-End}Conclusion This method can be used for trace analysis of DMT, TMT, DET, and TET in whole blood.

Objective: To investigate the specificity of endogenous metabolic profile in plasma of patients with occupational acute methyl acetate poisoning using non-targeted metabolomics. Methods: A total of six patients with occupational acute methyl acetate poisoning were selected as the poisoning group, while 10 healthy workers without occupational exposure history of chemical hazards in the same industry were selected as the control group using the judgment sampling method. Metabolites in patient plasma of the two groups were detected using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry, and non-targeted metabolomics analysis was performed. Principal component analysis and partial least squares discriminant analysis were used to identify differential metabolites and analyze their metabolic pathways. Results: There were significant differences in metabolite profiles in patient plasma between poisoning group and control group. A total of 195 differentially expressed metabolites were screened in plasma of patients in poisoning group, including 119 upregulated and 76 downregulated metabolites. Lipid substances (lipids and lipid-like molecules) accounted for the highest proportion (21.5%). The differential metabolites of poisoning group were related to folate biosynthesis, amino acid metabolism, pyrimidine metabolism, sphingolipid biosynthesis and other metabolic pathways in plasma compared with the control group (all P<0.05). Conclusion: Occupational acute methyl acetate poisoning affects metabolism of the body. The folic acid biosynthesis, amino acid and lipid metabolism and other pathways may be involved in the occurrence and development of poisoning.

Objective To establish a rapid qualitative analysis method for volatile organic components in chemicals. Methods Headspace gas chromatography-mass spectrometry was used to qualitatively determine 19 volatile organic components, including benzene, 1,2-dichloroethane, and n-hexane, in chemicals. Different sample amounts, heating temperatures, heating times, and sample volumes were analyzed to assess their effects on detection results and optimize sampling conditions. Results Based on the set chromatography, the optimal sampling process of this method was as follows： 5.0 g sample in a 20.0 mL headspace bottle, incubated at 40 ℃ for 30 minutes in a constant-temperature drying incubator, and a 1.00 mL headspace gas injection. The within-run and between-run relative standard deviations of all components ranged from 0.00% to 21.05% and 0.00% to 33.33%, respectively. The samples stored in sealed glass containers were stable at room temperature for at least 60 days. Conclusion This method offers simplicity, good reproducibility, and stability, making it suitable for rapid qualitative analysis of volatile organic components in chemicals.

Objective To establish a high performance liquid chromatography (HPLC) method for simultaneous determination of six aniline compounds (ADs) in workplace air. Methods GDH-1 air sampling tube was used to collect six co-existing ADs such as aniline, o-toluidine, N-methylaniline, m-methylaniline, p-methylaniline and N,N-dimethylaniline in the vapor and aerosol of workplace air. The samples were desorbed and eluted using a methanol solution containing 1.00% ammonia water, followed by separation on a C₁₈ chromatographic column and detection using a diode array detector. Results The quantification range of the method was 0.19 -253.50 mg/L, with the correlation coefficient of 0.999 9 for all six ADs. The minimum detection range was 0.02-0.06 mg/m³, and the minimum quantitation range was 0.04-0.19 mg/m³ [both calculated for a 15.0 L sample with a desorption (elution) solution volume of 3.00 mL]. The average desorption and elution efficiencies were 92.15%-104.41% (silica gel) and 94.29%-104.29% (filter membrane). The intra-assay relative standard deviation (RSD) ranged from 0.90%-9.72% (silica gel) and 0.57%-6.96% (filter membrane). The inter-assay RSD ranged from 2.03%-9.78% (silica gel) and 2.50%-8.62% (filter membrane). The samples were stable at room temperature for seven days. Conclusion This method can be used for the simultaneous determination of six ADs in workplace air.

To investigate the expression of polyadenosine diphospho-ribose polymerase 1 (PARP-1) and p16/ retinoblastoma (Rb) protein in hydroquinone (HQ)-induced TK6 cells and their regulatory mechanisms. Methods According to the 2×2 factorial design model, TK6 cells were divided into PBS-TK6 group and HQ-TK6 group based on HQ exposure, and then sub-divided into non-DOX intervention subgroup and DOX intervention subgroup based on DOX intervention, a total of four groups. The PBS-TK6 group was treated with phosphate buffer saline, and the HQ-TK6 group was treated with HQ at a final concentration of 20.0 μmol/L. The non-DOX intervention subgroup was added with 0.05% dimethyl sulfoxide; and the DOX intervention subgroup was added with PARP-1 agonist DOX at a final concentration of 0.5 μmol/L. The distribution of cell cycle was detected by flow cytometry. The protein expression of p16/Rb, cyclin D1 (cyclinD1), multifunctional protein E2 transcription factor 1 (E2F1), Rb, and p-Rb were detected by Western blot, and the level of p16 ribosylation was detected by immunofluorescence and immunoprecipitation. Results Compared with the PBS-TK6 group, the cell cycle distribution percentage in G0/G1 phase and the relative expression levels of p16 proteins were decreased in the cells of the HQ-TK6 group (all P<0.05). The cell cycle distribution percentage in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were up-regulated (all P<0.05). Compared with the non-DOX intervention group, the cell cycle distribution percentage in G0/G1 and G2/M phases and the relative expression level of p16 protein increased in the DOX intervention group (all P<0.05). The percentage of cells in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were down-regulated (all P< 0.05). The results of interaction effect analysis showed that compared with the non-DOX PBS-TK6 cells, the relative expression levels of Rb and E2F1 protein in the DOX PBS-TK6 cells intervention group were down-regulated (all P<0.05). The relative expression level of Rb protein in non-DOX HQ-TK6 cell group was down-regulated (P<0.05), and the relative expression of E2F1 protein was up-regulated (P<0.05). Compared with DOX PBS-TK6 cell group, the relative expression level of Rb protein in DOX HQ-TK6 cell group was down-regulated and that of E2F1 protein was up-regulated (all P<0.05). Compared with the non-DOX HQ-TK6 cell group, the relative expression level of Rb protein in the DOX HQ-TK6 cell group was up-regulated and that of E2F1 protein was down-regulated (all P<0.05). Conclusion PARP-1 participates in cell cycle regulation by regulating the p16/Rb signaling pathway in TK6 cells.

Objective: To explore effects of dendritic epidermal T cells (DETCs) and Vγ4 T lymphocytes on proliferation and differentiation of mice epidermal cells and the effects in wound healing of mice. Methods: (1) Six C57BL/6 male mice aged 8 weeks were collected and divided into control group and wound group according to random number table (the same grouping method below), with 3 mice in each group. A 4 cm long straight excision with full-thickness skin defect was cut on back of each mouse in wound group, while mice in control group received no treatment. On post injury day (PID) 3, mice in 2 groups were sacrificed, and skin within 5 mm from the wound margin on back of mice in wound group and normal skin on corresponding part of mice in control group were collected to make single cell suspensions. The percentage of Vγ4 T lymphocyte expressing interleukin-17A (IL-17A) and percentage of DETCs expressing insulin-like growth factor Ⅰ (IGF-Ⅰ) were detected by flow cytometer. (2) Ten C57BL/6 male mice aged 8 weeks were collected and divided into control group and Vγ4 T lymphocyte depletion group with 5 mice in each group. Mice in Vγ4 T lymphocyte depletion group were injected with 200 g Vγ4 T lymphocyte monoclonal neutralizing antibody of Armenian hamster anti-mouse intraperitoneally, and mice in control group were injected with the same amount of Armenian hamster Ig intraperitoneally. One hole with full-thickness skin defect was made on each side of spine of back of each mice. The wound healing was observed on PID 1-8, and percentage of remaining wound area was calculated. (3) Six C57BL/6 male mice aged 8 weeks were grouped and treated in the same way as in experiment (2), with 3 mice in each group. On PID 3, expressions of IL-17A and IGF-Ⅰ in epidermis on margin of wound were detected with Western blotting. (4) Thirty C57BL/6 male mice aged 3 days were sacrificed, and epidermal cells were extracted. The keratin 14 positive cell rate was examined by flow cytometer (the same detecting method below). (5) Another batch of mouse epidermal cells were collected and divided into control group, IGF-Ⅰ group, and IL-17A group, with 3 wells in each group (the same well number below). Cells in IGF-Ⅰ group and IL-17A group were added with 1 mL recombinant mouse IGF-Ⅰ and IL-17A with final mass concentration of 100 ng/mL respectively, while cells in control group were added with the same amount of sterile phosphate buffered saline (PBS). On post culture day (PCD) 5, keratin 14 negative cell rate was examined. Another batch of mouse epidermal cells were collected, grouped, and treated in the same way as aforementioned experiment, and keratin 10 positive cell rate was examined on PCD 10. (6) Another batch of mouse epidermal cells were collected and added with 4 mmol/L 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) solution, and divided into control 0 d group, control 7 d group, IGF-Ⅰ group, and IL-17A group. Cells in IGF-Ⅰ group and IL-17A group were treated in the same way as the corresponding groups in experiment (5), and cells in control 0 d group and control 7 d group were treated in the same way as the control group in experiment (5). The CFSE fluorescence peaks were examined on PCD 0 of control 0 d group and PCD 7 of the other 3 groups. (7) Another batch of mouse epidermal cells were collected and divided into control group and IGF-Ⅰ group. Cells in IGF-Ⅰ group were added with 1 mL recombinant mouse IGF-Ⅰ with final mass concentration of 100 ng/mL, and cells in control group were added with the same amount of sterile PBS. On PCD 5, cells were underwent keratin 14 staining and CFSE staining as aforementioned, and keratin 14 negative cell rate of CFSE positive cells was examined. Another batch of mouse epidermal cells were collected and divided into control group and IL-17A group. Cells in IL-17A group were added with 1 mL recombinant mouse IL-17A with final mass concentration of 100 ng/mL, and cells in control group were added with the same amount of sterile PBS. On PCD 5, keratin 14 negative cell rate of CFSE positive cells was examined. Data were processed with one-way analysis of variance and t test. Results: (1) On PID 3, percentage of DETC expressing IGF-Ⅰ in normal epidermis of control group was (9.9±0.8)%, significantly lower than (19.0±0.6)% of epidermis around margin of wound group (t=8.70, P<0.01); percentage of Vγ4 T lymphocyte expressing IL-17A in normal epidermis of control group was (0.123±0.024)%, significantly lower than (8.967±0.406)% of epidermis around margin of wound group (t=21.77, P<0.01). (2) On PID 1-4, there was obvious inflammatory reaction around wounds of mice in control group, and on PID 5-8, the wound area was still large. On PID 1-4, there was slight inflammatory reaction around wounds of mice in Vγ4 T lymphocyte depletion group, and on PID 5-8, the wound area was significantly reduced. On PID 3-7, percentages of residual wound area in Vγ4 T lymphocyte depletion group were significantly lower than those in control group (t=5.92, 5.74, 7.17, 5.38, 5.57, P<0.01), while percentages of residual wound area in two groups on PID 1, 2, 6 were similar (t=1.46, 3.17, 3.10, P>0.05). (3) On PID 3, compared with those in control group, expression of IL-17A and IGF-Ⅰ in epidermis around wound margin of mice in Vγ4 T lymphocyte depletion group was markedly decreased and increased respectively (t=8.47, 19.24, P<0.01). (4) The keratin 14 positive cell rate of mouse epidermal cells was 94.7%. (5) On PCD 5, the keratin 14 negative cell rate of mice in control group was markedly higher than that of IGF-Ⅰ group, while significantly lower than that of IL-17A group (t=7.25, 5.64, P<0.01). On PCD 10, the keratin 10 positive cell rate of mice in control group was significantly higher than that of IGF-Ⅰ group, while significantly lower than that of IL-17A group (t=3.99, 10.82, P<0.05 or P<0.01). (6) Compared with that of control 0 d group, CFSE fluorescence peaks of mouse epidermal cells in control 7 d group, IGF-Ⅰ group, and IL-17A group on PCD 7 shifted to the left. Compared with that of control 7 d group, CFSE fluorescence peaks of mouse epidermal cells in IGF-Ⅰ group and IL-17A group on PCD 7 shifted to the left. (7) On PCD 5, keratin 14 negative cell rate of CFSE positive cells of mice in control group was significantly higher than that in IGF-Ⅰ group (t=9.91, P<0.01), and keratin 14 negative cell rate of CFSE positive cells of mice in control group was markedly lower than that in IL-17A group (t=6.49, P<0.01). Conclusions In the process of wound healing, IGF-Ⅰ secreted by DETC can promote the proliferation of mouse keratin 14 positive epidermal cells and inhibit their terminal differentiation, while IL-17A secreted by Vγ4 T lymphocyte can promote the proliferation and terminal differentiation of mouse keratin 14 positive epidermal cells, thus both IGF-Ⅰ and IL-17A can affect wound healing.