Immobilized enzyme-based enzyme electrode biosensors, characterized by high sensitivity and efficiency, strong specificity, and compact size, demonstrate broad application prospects in life science research, disease diagnosis and monitoring, etc. Immobilization of enzyme is a critical step in determining the performance (stability, sensitivity, and reproducibility) of the biosensors. Random immobilization (physical adsorption, covalent cross-linking, etc.) can easily bring about problems, such as decreased enzyme activity and relatively unstable immobilization. Whereas, directional immobilization utilizing amino acid residue mutation, affinity peptide fusion, or nucleotide-specific binding to restrict the orientation of the enzymes provides new possibilities to solve the problems caused by random immobilization. In this paper, the principles, advantages and disadvantages and the application progress of enzyme electrode biosensors of different directional immobilization strategies for enzyme molecular sensing elements by specific amino acids (lysine, histidine, cysteine, unnatural amino acid) with functional groups introduced based on site-specific mutation, affinity peptides (gold binding peptides, carbon binding peptides, carbohydrate binding domains) fused through genetic engineering, and specific binding between nucleotides and target enzymes (proteins) were reviewed, and the application fields, advantages and limitations of various immobilized enzyme interface characterization techniques were discussed, hoping to provide theoretical and technical guidance for the creation of high-performance enzyme sensing elements and the manufacture of enzyme electrode sensors.

OBJECTIVE: To explore the effect mechanism of electroacupuncture (EA) for ameliorating diabetic peripheral neuropathy (DPN) based on the analysis of gut microbiota and metabolomics. METHODS: Thirty SPF-grade male SD rats were randomly divided into a normal group, a model group, and an EA group, with 10 rats in each one. Except in the normal group, the intraperitoneally injection with streptozotocin was used to induce diabetes mellitus model in the rest groups. In the EA group, acupuncture was delivered at bilateral "Zusanli" (ST36), "Sanyinjiao" (SP6), "Pishu" (BL20) and "Shenshu" (BL23), and electric stimulation was attached to "Zusanli" (ST36)-"Sanyinjiao" (SP6) and "Pishu" (BL20)-"Shenshu" (BL23), on the same side, with continuous wave and a frequency of 2 Hz, for 10 min in each intervention. The intervention measure of each group was delivered once every 2 days, 3 times a week, for 8 consecutive weeks. Body weight, random blood glucose (RBG), thermal withdrawal latency (TWL), and mechanical withdrawal threshold (MWT) before intervention, and in 4 and 8 weeks of intervention, separately, as well as sensory nerve conduction velocity (SCV) and motor nerve conduction velocity (MCV) of the sciatic nerve after intervention were measured. Metagenomic sequencing (MS) was used to analyze gut microbiota and screen for differential species. Liquid chromatography-mass spectrometry (LC-MS) was employed to detect the differential metabolites in plasma, and the metabolic pathway enrichment analysis was performed on the differential metabolites. Spearman correlation analysis was adopted to assess the relationship between gut microbiota and metabolomics. RESULTS: After 4 and 8 weeks of intervention, when compared with the model group, the EA group showed the increase in body weight, TWL, MWT (P<0.01), and the decrease in RBG (P<0.01). Compared with the normal group, SCV and MCV, as well as Chao1 index were dropped in the model group (P<0.01), and those were elevated in the EA group when compared with those in the model group (P<0.01). The dominant bacterial phyla of each group were Firmicutes (F) and Bacteroidota (B), the ratio of them (F/B) in the model group was lower than that of the normal group (P<0.05), and F/B in the EA group was higher when compared with that in the model group (P<0.05). In comparison with the normal group, the relative abundance increased in Prevotella, Segatella, Prevotella-hominis and Segatella-copri (P<0.05); and it decreased in Ligilactobacillus, Eubacterium, Pseudoflavonifractor, Ligilactobacillus-murinus (P<0.05) in the model group. Compared with the model group, the relevant abundance of the above mentioned gut bacteria was all ameliorated in the EA group (P<0.05, P<0.01). Among the three groups, 120 differential metabolites were identified and enriched in 28 key metabolic pathways, such as glycerophospholipid and linoleic acid, of which, glycerophospholipid was the most significantly affected pathway in EA intervention. Spearman correlation analysis showed that 6 phosphatidylcholine metabolites were significantly positively correlated with Pseudoflavonifractor and were negatively with Prevotella, Segatella, Prevotella-hominis, Segatella-copri; 5 phosphatidylethanolamine metabolites were significantly negatively correlated with Pseudoflavonifractor and positively correlated with Prevotella, Segatella, Prevotella-hominis, Segatella-copri. CONCLUSION EA may regulate metabolic pathways such as glycerophospholipid, modulate specific gut microbiota such as Pseudoflavonifractor, Prevotella, and Segatella, and the co-expressed differential metabolites like phosphatidylcholine and phosphatidylethanolamine, thereby reducing blood glucose and protecting nerve function, so as to relieve the symptoms of DPN of rats.
Animals ; Electroacupuncture ; Male ; Gastrointestinal Microbiome ; Diabetic Neuropathies/microbiology* ; Rats, Sprague-Dawley ; Rats ; Metabolomics ; Humans ; Acupuncture Points

This study explores the effect of total secondary ginsenosides(TSG) on apoptosis and energy metabolism in H9c2 cells under hypoxia and its potential mechanisms. H9c2 cell viability was observed and the apoptosis rate was calculated to determine suitable intervention concentrations of TSG, antimycin A complex(AMA), and coenzyme Q10(CoQ10), along with the duration of hypoxia. H9c2 cells at the logarithmic phase were divided into a normal group, a model group, a TSG group, an AMA group, a TSG+AMA group, and a CoQ10 group. All groups, except the normal group, were treated with their respective intervention drugs and cultured under hypoxic conditions. Adenosine triphosphate(ATP) content and creatine kinase(CK) activity were measured using an ATP chemiluminescence assay kit and a CK colorimetric assay kit. Flow cytometry was used to assess apoptosis rates, and Western blot evaluated the expression levels of apoptosis-related proteins, including B-cell lymphoma 2(Bcl-2), Bcl-2-associated X protein(Bax), cysteinyl aspartate-specific protease(caspase)-3, caspase-8, and caspase-9, as well as mitochondrial biogenesis-related proteins peroxisome proliferator-activated receptor-γ coactivator 1α(PGC-1α), estrogen-related receptor-α(ERRα), nuclear respiratory factor(NRF)-1, NRF-2, peroxisome proliferator activated receptor-α(PPARα), and Na~+-K~+-ATPase. RT-PCR was employed to analyze the mRNA expression of mitochondrial biogenesis factors, including PGC-1α, ERRα, NRF-1, NRF-2, PPARα, mitochondrial transcription factor A(TFAM), mitochondrial cytochrome C oxidase 1(COX1), and mitochondrial NADH dehydrogenase subunit 1(ND1), ND2. The selected intervention concentrations were 7.5 μg·mL~(-1) for TSG, 10 μmol·L~(-1) for AMA, and 1×10~(-4) mol·L~(-1) for CoQ10, with a hypoxia duration of 6 h. Compared with the normal group, the model group showed decreased ATP content and CK activity, increased apoptosis rates, decreased Bcl-2 expression, and increased Bax, caspase-3, caspase-8, and caspase-9 expression in H9c2 cells. Additionally, the protein and mRNA expression levels of mitochondrial biogenesis-related factors(PGC-1α, ERRα, NRF-1, NRF-2, PPARα), mRNA expression of TFAM, COX1, and ND1, ND2, and protein expression of Na~+-K~+-ATPase in mitochondrial DNA, were also reduced. In the TSG and CoQ10 groups, ATP content and CK activity increased, and apoptosis rates decreased compared with those in the model group. The TSG group showed decreased protein expression of apoptosis-related proteins Bax, caspase-3, caspase-8, and caspase-9, increased protein and mRNA expression of mitochondrial biogenesis factors PGC-1α, ERRα, NRF-1, and PPARα, and increased NRF-2 protein expression and TFAM mRNA expression in mitochondrial DNA. Conversely, in the AMA group, ATP content and CK activity decreased, the apoptosis rate increased, Bcl-2 expression decreased, and Bax, caspase-3, caspase-8, and caspase-9 expression increased, alongside reductions in PGC-1α, ERRα, NRF-1, NRF-2, PPARα protein and mRNA expression, as well as TFAM, COX1, ND1, ND2 mRNA expression and Na~+-K~+-ATPase protein expression. Compared with the TSG group, the TSG+AMA group exhibited decreased ATP content and CK activity, increased apoptosis rates, decreased Bcl-2 expression, and increased Bax, caspase-3, caspase-8, and caspase-9 expression, along with decreased PGC-1α, ERRα, NRF-1, NRF-2, and PPARα protein and mRNA expression and TFAM, COX1, and ND1, ND2 mRNA expression. Compared with the AMA group, the TSG+AMA group showed increased CK activity, decreased apoptosis rate, increased Bcl-2 expression, and decreased Bax, caspase-8, and caspase-9 expression. Additionally, the protein and mRNA expression of PGC-1α, ERRα, NRF-1, PPARα, mRNA expression of TFAM, COX1, ND1, ND2, and Na~+-K~+-ATPase protein expression increased. In conclusion, TSG enhance ATP content and CK activity and inhibit apoptosis in H9c2 cells under hypoxia, and the mechanisms may be related to the regulation of PGC-1α, ERRα, NRF-1, NRF-2, PPARα, and TFAM expression, thus promoting mitochondrial biogenesis.
Apoptosis/drug effects* ; Ginsenosides/pharmacology* ; Energy Metabolism/drug effects* ; Mitochondria/metabolism* ; Animals ; Rats ; Cell Line ; Cell Hypoxia/drug effects* ; Organelle Biogenesis ; Adenosine Triphosphate/metabolism* ; Humans ; Cell Survival/drug effects*

In this study, lipopolysaccharide(LPS), ovalbumin(OVA), and compound 48/80(C48/80) were administered to establish non-infectious pneumonia models under simulated clinical conditions, and the correlation between their pathological characteristics and traditional Chinese medicine(TCM) syndromes was compared, providing the basis for the selection of appropriate animal models for TCM efficacy evaluation. An acute pneumonia model was established by nasal instillation of LPS combined with intraperitoneal injection for intensive stimulation. Three doses of OVA mixed with aluminum hydroxide adjuvant were injected intraperitoneally on days one, three, and five and OVA was administered via endotracheal drip for excitation on days 14-18 to establish an OVA-induced allergic pneumonia model. A single intravenous injection of three doses of C48/80 was adopted to establish a C48/80-induced pneumonia model. By detecting the changes in peripheral blood leukocyte classification, lung tissue and plasma cytokines, immunoglobulins(Ig), histamine levels, and arachidonic acid metabolites, the multi-dimensional analysis was carried out based on pathological evaluation. The results showed that the three models could cause pulmonary edema, increased wet weight in the lung, and obvious exudative inflammation in lung tissue pathology, especially for LPS. A number of pyrogenic cytokines, inclading interleukin(IL)-6, interferon(IFN)-γ, IL-1β, and IL-4 were significantly elevated in the LPS pneumonia model. Significantly increased levels of prostacyclin analogs such as prostaglandin E2(PGE2) and PGD2, which cause increased vascular permeability, and neutrophils in peripheral blood were significantly elevated. The model could partly reflect the clinical characteristics of phlegm heat accumulating in the lung or dampness toxin obstructing the lung. The OVA model showed that the sensitization mediators IgE and leukotriene E4(LTE4) were increased, and the anti-inflammatory prostacyclin 6-keto-PGF2α was decreased. Immune cells(lymphocytes and monocytes) were decreased, and inflammatory cells(neutrophils and basophils) were increased, reflecting the characteristics of "deficiency", "phlegm", or "dampness". Lymphocytes, monocytes, and basophils were significantly increased in the C48/80 model. The phenotype of the model was that the content of histamine, a large number of prostacyclins(6-keto-PGE1, PGF2α, 15-keto-PGF2α, 6-keto-PGF1α, 13,14-D-15-keto-PGE2, PGD2, PGE2, and PGH2), LTE4, and 5-hydroxyeicosatetraenoic acid(5S-HETE) was significantly increased, and these indicators were associated with vascular expansion and increased vascular permeability. The pyrogenic inflammatory cytokines were not increased. The C48/80 model reflected the characteristics of cold and damp accumulation. In the study, three non-infectious pneumonia models were constructed. The LPS model exhibited neutrophil infiltration and elevated inflammatory factors, which was suitable for the efficacy study of TCM for clearing heat, detoxifying, removing dampness, and eliminating phlegm. The OVA model, which took allergic inflammation as an index, was suitable for the efficacy study of Yiqi Gubiao formulas. The C48/80 model exhibited increased vasoactive substances(histamine, PGs, and LTE4), which was suitable for the efficacy study and evaluation of TCM for warming the lung, dispersing cold, drying dampness, and resolving phlegm. The study provides a theoretical basis for model selection for the efficacy evaluation of TCM in the treatment of pneumonia.
Animals ; Disease Models, Animal ; Mice ; Pneumonia/genetics* ; Medicine, Chinese Traditional ; Male ; Humans ; Cytokines/immunology* ; Female ; Lipopolysaccharides/adverse effects* ; Lung/drug effects* ; Drugs, Chinese Herbal ; Ovalbumin ; Mice, Inbred BALB C

OBJECTIVE: To explore the role of antibiotic-eluting absorbable calcium sulfate in treating periprosthetic infection after one-stage revision of knee arthroplasty. METHODS: A retrospective analysis was performed on 36 patients(36 knees)who underwent phaseⅠrevision for periprosthesis infection after total knee arthroplasty from January 2018 to March 2022. All patients were underwent knee cavity puncture before operation and had positive results of aseptic body fluid culture, 21 patients received revision combined with antibiotic loaded calcium sulfate at stageⅠ(calcium sulfate group) during operation, and 15 patients underwent renovation at stageⅠ(revision group). There were 9 males and 12 females in calcium sulfate group, aged from 54 to 76 years old with an average of(67.6±6.2) years old. There were 15 patients in revision group, including 4 males and 11 females, aged from 60 to 75 years old with average of (69.6±4.1) years old. The levels of serum C-reactive protein (CRP), interleukin-6 (IL-6) at 7, 14, 30 and 90 days after operation were compared between two groups, and the rate of end-infection control at follow-up were compared. The systemic antibiotic application time, hospital stay and postoperative complications were observed between two groups. RESULTS: Calcium sulfate group were followed up for 12 to 29 months with an average of(18.9±4.2) months, and the infection control rate was 90.5%;while revision group were followed up 18 to 29 months with average of (21.6±3.7) months, and the infection control rate was 86.7% (13/15). There were no significant differences in follow-up time and infection control rate between two groups(P>0.05). Postoperative levels of CRP and IL-6 at 7, 14 and 30 days in calcium sulfate group were (32.79±11.48), (15.50±6.52), (9.36±3.32) mg·L^-1 and (17.31±6.15) pg·ml^-1, respectively;which were lower than those in revision group (40.65±11.32), (30.15±10.57), (18.97±5.86) mg·L^-1 and (25.54±6.73) pg·ml^-1, had statistical differences(P<0.05). There were no significant differences in IL-6 levels at 7 and 14 days after operation and CRP levels at 90 days after operation between two groups (P>0.05). The hospitalization time and systemic antibiotic application time in calcium sulfate group were (18.4±2.2) and (63.5±21.4) d, respectively;which were better than those in revision group (20.5±2.4) and (82.7±16.9) d, and had statistical differences(P<0.05). No significant wound complications and hypercalcemia were observed in calcium sulfate group. CONCLUSION Antibiotic eluted absorbable calcium sulfate could be used to treat periprosthetic knee infection, significantly reducing CRP levels in the early postoperative period, shortening hospital stay and systemic antibiotic application time, but it does not significantly improve the control rate of revision infection at stageⅠ.
Humans ; Male ; Female ; Aged ; Prosthesis-Related Infections/surgery* ; Middle Aged ; Calcium Sulfate/administration & dosage* ; Arthroplasty, Replacement, Knee/adverse effects* ; Retrospective Studies ; Anti-Bacterial Agents/therapeutic use* ; Interleukin-6/blood* ; C-Reactive Protein/metabolism* ; Reoperation ; Knee Prosthesis/adverse effects*

OBJECTIVE: To evaluate the dynamic changes of glucocorticoid (GC) dose and the feasibility of GC discontinuation in rheumatoid arthritis (RA) patients under the background of Chinese medicine (CM). METHODS: This multicenter retrospective cohort study included 1,196 RA patients enrolled in the China Rheumatoid Arthritis Registry of Patients with Chinese Medicine (CERTAIN) from September 1, 2019 to December 4, 2023, who initiated GC therapy. Participants were divided into the Western medicine (WM) and integrative medicine (IM, combination of CM and WM) groups based on medication regimen. Follow-up was performed at least every 3 months to assess dynamic changes in GC dose. Changes in GC dose were analyzed by generalized estimator equation, the probability of GC discontinuation was assessed using Kaplan-Meier curve, and predictors of GC discontinuation were analyzed by Cox regression. Patients with <12 months of follow-up were excluded for the sensitivity analysis. RESULTS: Among 1,196 patients (85.4% female; median age 56.4 years), 880 (73.6%) received IM. Over a median 12-month follow-up, 34.3% (410 cases) discontinued GC, with significantly higher rates in the IM group (40.8% vs. 16.1% in WM; P<0.05). GC dose declined progressively, with IM patients demonstrating faster reductions (median 3.75 mg vs. 5.00 mg in WM at 12 months; P<0.05). Multivariate Cox analysis identified age <60 years [P<0.001, hazard ratios (HR)=2.142, 95% confidence interval (CI): 1.523-3.012], IM therapy (P=0.001, HR=2.175, 95% CI: 1.369-3.456), baseline GC dose ⩽7.5 mg (P=0.003, HR=1.637, 95% CI: 1.177-2.275), and absence of non-steroidal anti-inflammatory drugs use (P=0.001, HR=2.546, 95% CI: 1.432-4.527) as significant predictors of GC discontinuation. Sensitivity analysis (545 cases) confirmed these findings. CONCLUSIONS RA patients receiving CM face difficulties in following guideline-recommended GC discontinuation protocols. IM can promote GC discontinuation and is a promising strategy to reduce GC dependency in RA management. (Trial registration: ClinicalTrials.gov, No. NCT05219214).
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Arthritis, Rheumatoid/drug therapy* ; Glucocorticoids/therapeutic use* ; Medicine, Chinese Traditional ; Retrospective Studies

OBJECTIVE: To evaluate the clinical effect and safety of acupuncture manipulation on treatment of intractable facial paralysis (IFP), and verify the practicality and precision of the Anzhong Facial Paralysis Precision Scale (Eyelid Closure Grading Scale, AFPPS-ECGS). METHODS: A multicentre, single-blind, randomized controlled trial was conducted from October 2022 to June 2024. Eighty-nine IFP participants were randomly assigned to an ordinary acupuncture group (OAG, 45 cases) and a characteristic acupuncture group (CAG, 44 cases) using a random number table method. The main acupoints selected included Yangbai (GB 14), Quanliao (SI 18), Yingxiang (LI 20), Shuigou (GV 26), Dicang (ST 4), Chengjiang (CV 24), Taiyang (EX-HN 5), Jiache (ST 6), Fengchi (GB 20), and Hegu (LI 4). The OAG patients received ordinary acupuncture manipulation, while the CAG received characteristic acupuncture manipulation. Both groups received acupuncture treatment 3 times a week, with 10 times per course, lasting for 10 weeks. Facial recovery was assessed at baseline and after the 1st, 2nd and 3rd treatment course by AFPPS-ECGS and the House-Brackmann (H-B) Grading Scale. Infrared thermography technology was used to observe the temperature difference between healthy and affected sides in various facial regions. Adverse events and laboratory test abnormalities were recorded. The correlation between the scores of the two scales was analyzed using Pearson correlation coefficient. RESULTS: After the 2nd treatment course, the two groups showed statistically significant differences in AFPPS-ECGS scores (P<0.05), with even greater significance after the 3rd course (P<0.01). Similarly, H-B Grading Scale scores demonstrated significant differences between groups following the 3rd treatment course (P<0.05). Regarding temperature measurements, significant differences in temperatures of frontal and ocular areas were observed after the 2nd course (P<0.05), becoming more pronounced after the 3rd course (P<0.01). Additionally, mouth corner temperature differences reached statistical significance by the 3rd course (P<0.05). No safety-related incidents were observed during the study. Correlation analysis revealed that the AFPPS-ECGS and the H-B Grading Scale were strongly correlated (r=0.86, 0.91, 0.93, and 0.91 at baseline, and after 1st, 2nd, and 3rd treatment course, respectively, all P<0.01). CONCLUSIONS Acupuncture is an effective treatment for IFP, and the characteristic acupuncture manipulation enhances the therapeutic effect. The use of the AFPPS-ECGS can more accurately reflect the recovery status of patients with IFP. (Trial registration No. ChiCTR2200065442).
Humans ; Acupuncture Therapy/methods* ; Facial Paralysis/therapy* ; Female ; Male ; Middle Aged ; Adult ; Treatment Outcome ; Acupuncture Points ; Aged

Early-life stress (ES) leads to cognitive dysfunction in female adolescents, but the underlying neural mechanisms remain elusive. Recent evidence suggests that the cell adhesion molecules NECTIN1 and NECTIN3 play a role in cognition and ES-related cognitive deficits in male rodents. In this study, we aimed to investigate whether and how nectins contribute to ES-induced cognitive dysfunction in female adolescents. Applying the well-established limited bedding and nesting material paradigm, we found that ES impairs recognition memory, suppresses prefrontal NECTIN1 and hippocampal NECTIN3 expression, and upregulates corticotropin-releasing hormone (Crh) and its receptor 1 (Crhr1) mRNA levels in the hippocampus of adolescent female mice. Genetic experiments revealed that the reduction of dorsal CA1 (dCA1) NECTIN3 mediates ES-induced object recognition memory deficits, as knocking down dCA1 NECTIN3 impaired animals' performance in the novel object recognition task, while overexpression of dCA1 NECTIN3 successfully reversed the ES-induced deficits. Notably, prefrontal NECTIN1 knockdown did not result in significant cognitive impairments. Furthermore, acute systemic administration of antalarmin, a CRHR1 antagonist, upregulated hippocampal NECTIN3 levels and rescued object and spatial memory deficits in stressed mice. Our findings underscore the critical role of dCA1 NECTIN3 in mediating ES-induced object recognition memory deficits in adolescent female mice, highlighting it as a potential therapeutic target for stress-related psychiatric disorders in women.
Animals ; Female ; Mice ; CA1 Region, Hippocampal/metabolism* ; Cell Adhesion Molecules/metabolism* ; CRF Receptor, Type 1/metabolism* ; Memory Disorders/etiology* ; Mice, Inbred C57BL ; Nectins/genetics* ; Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors* ; Recognition, Psychology/physiology* ; Stress, Psychological/complications*

OBJECTIVE: Exposure to polycyclic aromatic hydrocarbons (PAHs) or metal(loid)s individually has been associated with neural tube defects (NTDs). However, the impacts of PAH and metal(loid) co-exposure and potential interaction effects on NTD risk remain unclear. We conducted a case-control study in China among population with a high prevalence of NTDs to investigate the combined effects of PAH and metal(loid) exposures on the risk of NTD. METHODS: Cases included 80 women who gave birth to offspring with NTDs, whereas controls were 50 women who delivered infants with no congenital malformations. We analyzed the levels of placental PAHs using gas chromatography and mass spectrometry, PAH-DNA adducts with ³²P-post-labeling method, and metal(loid)s with an inductively coupled plasma mass spectrometer. Unconditional logistic regression was employed to estimate the associations between individual exposures and NTDs. Least absolute shrinkage and selection operator (LASSO) penalized regression models were used to select a subset of exposures, while additive interaction models were used to identify interaction effects. RESULTS: In the single-exposure models, we found that eight PAHs, PAH-DNA adducts, and 28 metal(loid)s were associated with NTDs. Pyrene, selenium, molybdenum, cadmium, uranium, and rubidium were selected through LASSO regression and were statistically associated with NTDs in the multiple-exposure models. Women with high levels of pyrene and molybdenum or pyrene and selenium exhibited significantly increased risk of having offspring with NTDs, indicating that these combinations may have synergistic effects on the risk of NTDs. CONCLUSION Our findings suggest that individual PAHs and metal(loid)s, as well as their interactions, may be associated with the risk of NTDs, which warrants further investigation.
Humans ; Neural Tube Defects/chemically induced* ; Polycyclic Aromatic Hydrocarbons/adverse effects* ; Female ; Case-Control Studies ; China/epidemiology* ; Adult ; Pregnancy ; Environmental Pollutants ; Maternal Exposure/adverse effects* ; Metals/toxicity* ; Young Adult ; Risk Factors