This paper primarily investigated the protective effects and potential mechanisms of total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma in alleviating isoprenaline(ISO)-induced hypertrophy and damage in H9c2 cardiomyocytes. Initially, H9c2 cardiomyocytes were used as the research subject to analyze the effects of ISO at different concentrations on cell hypertrophy and damage. On this basis, the H9c2 cardiomyocytes were divided into blank, model, and high-dose(200 μg·mL~(-1)), medium-dose(100 μg·mL~(-1)), and low-dose(50 μg·mL~(-1)) groups of total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma. Cell hypertrophy and damage models were induced by treating cells with 400 μmol·L~(-1) ISO for 24 hours. The Incucyte live-cell analysis system was utilized to observe the status, size changes, and confluence of the cells in each group. Cell viability was detected by using the CCK-8 assay. Western blot analysis was employed to detect the expression of Ras-associated protein 7A(RAB7A), sequestosome 1(SQSTM1/p62), autophagy-related protein Beclin1, and microtubule-associated protein 1 light chain 3(LC3). Immunofluorescence was used to detect the expression level of the autophagy marker Beclin1 in H9c2 cells. The results demonstrated that compared with the blank group, the model group showed a significant reduction in cell viability(P<0.01) and a marked increase in cell hypertrophy, with an average cell length growth of 13.53%. Compared with the model group, the high-dose, medium-dose, and low-dose groups of total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma exhibited reduced hypertrophy, with respective growths of 6.89%, 8.30%, and 8.49% and a significant decrease in growth rates(P<0.01). Cell viability in the high-dose of total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma was also significantly increased(P<0.01). Western blot and immunofluorescence results indicated that compared with the blank group, the model group showed changes in Beclin1, RAB7A, and p62 expression, as well as the LC3Ⅱ/LC3Ⅰ ratio, although most changes were not statistically significant. In the groups treated with total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma, the expression of autophagy-related proteins Beclin1 and RAB7A and the LC3Ⅱ/LC3Ⅰ ratio were significantly increased(P<0.05), while p62 expression significantly decreased(P<0.05). These findings collectively suggested that pretreatment of cells with total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma significantly enhanced autophagy activity in cells. In summary, total saponins from Ginseng Radix et Rhizoma and Notoginseng Radix et Rhizoma inhibit ISO-induced hypertrophy and damage in H9c2 cells by promoting autophagy, demonstrating potential cardioprotective effects and providing new insights and scientific evidence for their preventive and therapeutic use in cardiovascular diseases.
Autophagy/drug effects* ; Saponins/pharmacology* ; Panax notoginseng/chemistry* ; Panax/chemistry* ; Animals ; Rats ; Cell Line ; Drugs, Chinese Herbal/pharmacology* ; Rhizome/chemistry* ; Isoproterenol/adverse effects* ; Myocytes, Cardiac/cytology* ; Hypertrophy/drug therapy*

This paper explored the specific mechanism of ginsenoside Rg_1 in regulating mitochondrial fusion through the neurogenic gene Notch homologous protein 1(Notch1) pathway to alleviate hypoxia/reoxygenation(H/R) injury in HL-1 cells. The relative viability of HL-1 cells after six hours of hypoxia and two hours of reoxygenation was detected by cell counting kit-8(CCK-8). The lactate dehydrogenase(LDH) activity in the cell supernatant was detected by the lactate substrate method. The content of adenosine triphosphate(ATP) was detected by the luciferin method. Fluorescence probes were used to detect intracellular reactive oxygen species(Cyto-ROS) levels and mitochondrial membrane potential(ΔΨ_m). Mito-Tracker and Actin were co-imaged to detect the number of mitochondria in cells. Fluorescence quantitative polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels of Notch1, mitochondrial fusion protein 2(Mfn2), and mitochondrial fusion protein 1(Mfn1). The results showed that compared with that of the control group, the cell activity of the model group decreased, and the LDH released into the cell culture supernatant increased. The level of Cyto-ROS increased, and the content of ATP decreased. Compared with that of the model group, the cell activity of the ginsenoside Rg_1 group increased, and the LDH released into the cell culture supernatant decreased. The level of Cyto-ROS decreased, and the ATP content increased. Ginsenoside Rg_1 elevated ΔΨ_m and increased mitochondrial quantity in HL-1 cells with H/R injury and had good protection for mitochondria. After H/R injury, the mRNA and protein expression levels of Notch1 and Mfn1 decreased, while the mRNA and protein expression levels of Mfn2 increased. Ginsenoside Rg_1 increased the mRNA and protein levels of Notch1 and Mfn1, and decreased the mRNA and protein levels of Mfn2. Silencing Notch1 inhibited the action of ginsenoside Rg_1, decreased the mRNA and protein levels of Notch1 and Mfn1, and increased the mRNA and protein levels of Mfn2. In summary, ginsenoside Rg_1 regulated mitochondrial fusion through the Notch1 pathway to alleviate H/R injury in HL-1 cells.
Ginsenosides/pharmacology* ; Receptor, Notch1/genetics* ; Signal Transduction/drug effects* ; Mice ; Animals ; Mitochondrial Dynamics/drug effects* ; Mitochondria/metabolism* ; Cell Line ; Reactive Oxygen Species/metabolism* ; Oxygen/metabolism* ; Cell Hypoxia/drug effects* ; Cell Survival/drug effects* ; Membrane Potential, Mitochondrial/drug effects* ; Humans

Objective To establish a rapid screening method for 34 emerging contaminants in surface water by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry(UHPLC-Q-TOF-MS).Methods The pretreatment conditions of solid phase extraction(SPE)were op-timized by orthogonal experimental design and the surface water samples were concentrated and ex-tracted by Oasis? HLB and Oasis? MCX SPE columns in series.The extracts were separated by Kine-tex? EVO C18 column,with gradient elution of 0.1%formic acid aqueous solution and 0.1%formic acid methanol solution.Q-TOF-MS'fullscan'and'targeted MS/MS'modes were used to detect 34 emerging contaminants and to establish a database with 34 emerging contaminants precursor ion,prod-uct ion and retention times.Results The 34 emerging contaminants exhibited good linearity in the con-centration range respectively and the correlation coefficients(r)were higher than 0.97.The limit of de-tection was 0.2-10 ng/L and the recoveries were 81.2%-119.2%.The intra-day precision was 0.78%-18.70%.The method was applied to analyze multiple surface water samples and 6 emerging contaminants were detected,with a concentration range of 1.93-157.71 ng/L.Conclusion The method is simple and rapid for screening various emerging contaminants at the trace level in surface water.

Objective To analyze the distribution and antimicrobial resistance of pathogens from wounds of burned patients,providing reference for the rational use of antimicrobial agents and healthcare-associated infection(HAI)prevention and control.Methods Clinical data of burned patients admitted to a tertiary first-class hospital from Ja-nuary 2020 to December 2022 were analyzed retrospectively,pathogens in the wound was cultured,identified,and performed antimicrobial susceptibility analysis.Results From 2020 to 2022,a total of 588 burned patients were ad-mitted,734 strains of pathogens were detected,including 415 strains(56.54％)of Gram-negative bacteria,306 strains(41.69％)of Gram-positive bacteria,and 13(1.77％)strains of fungi.The top 5 pathogens were Staphy-lococcus aureus,Escherichia coli,Pseudomonas aeruginosa,Klebsiella pneumoniae,and Enterobacter cloacae.Staphylococcus aureus had higher resistance rates(93.02％-97.37％)to penicillin G,resistance rate to oxacillin increased from 11.63％to 21.92％.Pseudomonas aeruginosa mainly exhibited resistance to ticarcillin/clavulanic acid,aztreonam,and levofloxacin,resistance rates to imipenem and meropenem were 15.00％-38.10％and 10.00％-33.33％,respectively.Susceptibility of Enterobacterales bacteria to cephalosporins enhanced with the increased of cephalosporin generations,and exhibited higher resistance to commonly used antimicrobial agents.Conclusion Over the past three years,there has been no significant change in the detection of major pathogens and antimicrobial resistance in wounds of burned patients in this hospital.Antimicrobial resistance of Staphylococcus aureus and En-terobacterales is relatively severe,and it is necessary to carry out surveillance on pathogens from burn wounds in corresponding areas.

BACKGROUND: B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T (CAR-T) therapy yield remarkable responses in patients with relapsed/refractory multiple myeloma (R/RMM). Circulating tumor DNA (ctDNA) reportedly exhibits distinct advantages in addressing the challenges posed by tumor heterogeneity in the distribution and genetic variations in R/RMM. METHODS: Herein, the ctDNA of 108 peripheral blood plasma samples from patients with R/RMM was thoroughly investigated before administration of anti-BCMA CAR-T therapy to establish its predictive potential. Flow cytometry is used primarily to detect subgroups of T cells or CAR-T cells. RESULTS: In this study, several tumor and T cell effector-mediated factors were considered to be related to treatment failure by an integrat analysis, including higher percentages of multiple myeloma (MM) cells in the bone marrow (P = 0.013), lower percentages of CAR-T cells in the peripheral blood at peak (P = 0.037), and higher percentages of CD8+ T cells (P = 0.034). Furthermore, there is a substantial correlation between high ctDNA level (>143 ng/mL) and shorter progression-free survival (PFS) (P = 0.007). Multivariate Cox regression analysis showed that high levels of ctDNA (>143 ng/mL), MM-driven high-risk mutations (including IGLL5 [P = 0.004], IRF4 [P = 0.024], and CREBBP [P = 0.041]), number of multisite mutations, and resistance-related mutation (ERBB4, P = 0.040) were independent risk factors for PFS. CONCLUSION: Finally, a ctDNA-based risk model was built based on the above independent risk factors, which serves as an adjunct non-invasive measure of substantial tumor burden and a prognostic genetic feature that can assist in predicting the response to anti-BCMA CAR-T therapy. REGISTERATION Chinese Clinical Trial Registry (ChiCTR2100046474) and National Clinical Trial (NCT04670055, NCT05430945).

This study aimed to investigate the potential mechanism and the compatibility significance of Tanyu Tongzhi Formula in treating atherosclerosis(AS) in mice based on the transforming growth factor-β(TGF-β)/Smad2/3 signaling pathway. Eight C57BL/6J mice were as assigned to a normal control group and fed a regular diet, while 35 ApoE~(-/-) mice of the same strain were fed a high-fat diet for 8 weeks to establish an AS model. The model mice were randomly divided into a model group, a Tanyu Tongzhi group(18.2 mg·kg~(-1)), a Huatan(phlegm-resolving) group(10.4 mg·kg~(-1)), and a Quyu(blood stasis-resolving) group(7.8 mg·kg~(-1)), with 8 mice in each group. Except for the normal group, all other groups continued to be fed a high-fat diet for 8 weeks to maintain the AS model, and then the mice were treated by gavage for 8 weeks. Plasma levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), high-density lipoprotein cholesterol(HDL-C), interleukin-1β(IL-1β), and interleukin-18(IL-18) were measured using enzyme-linked immunosorbent assay(ELISA). Hematoxylin and eosin(HE) staining, oil red O staining, and Russell-Movat pentachrome staining were performed to observe the pathological changes in the aortic tissue. The proportions of aortic plaque area, lipid-stained area, collagen fibers, and elastic fibers were calculated. Immunofluorescence was used to detect the protein expression levels of matrix metalloproteinase 2(MMP2) and tissue inhibitor of metalloproteinases 2(TIMP2). Western blot was used to detect the protein expression levels of TGF-β1, TGF-β2, Smad2/3, and Smad7 in aortic tissue. Real-time fluorescence quantitative PCR(RT-qPCR) was used to measure the mRNA expression levels of TGF-β receptor(TGF-βR), TGF-β1, Smad2/3, Smad7, intercellular adhesion molecule-1(ICAM-1), and vascular cell adhesion molecule-1(VCAM-1) in aortic tissue. The results showed that compared with the normal control group, the model group had increased plasma TC and LDL-C, significantly decreased HDL-C, and significantly elevated plasma IL-1β and IL-18 levels. The model group also exhibited an increased proportion of aortic plaque area, lipid-stained area, and collagen fiber area, along with significantly upregulated MMP2 and downregulated TIMP2 expression in the aortic arch. Additionally, the expression levels of TGF-βR, TGF-β1, and p-Smad2/3 proteins and mRNA in the aortic tissue were significantly elevated, while Smad7 expression was decreased. Compared with the model group, the Tanyu Tongzhi group showed significantly reduced plasma TC and LDL-C levels, significantly increased HDL-C levels, and significantly decreased plasma IL-1β and IL-18 levels. The Tanyu Tongzhi group also exhibited a significant reduction in aortic plaque size and severity, a significant downregulation of MMP2 expression in the aortic arch, and significantly decreased ICAM-1 and VCAM-1 mRNA expression levels. Moreover, the Tanyu Tongzhi group demonstrated significantly reduced expression levels of TGF-β1 and p-Smad2/3 proteins and mRNA in the aortic tissue, and an increased expression level of Smad7 protein to varying degrees. Compared with the Tanyu Tongzhi group, the Quyu group had significantly higher LDL-C levels and elevated plasma IL-1β and IL-18 levels. The Huatan group showed upregulated MMP2 expression and downregulated TIMP2 expression in the aortic arch. In conclusion, Tanyu Tongzhi Formula, which is composed based on the pathogenesis of phlegm and blood stasis, maintains vascular homeostasis by primarily regulating lipid metabolism and controlling inflammatory factors through the Huatan group, and maintaining vascular wall permeability, inhibiting plaque development, and stabilizing plaques through the Quyu group. The mechanism of action may involve inhibiting TGF-β1 expression in the aorta, reducing Smad2/3 phosphorylation, and simultaneously increasing Smad7 expression.
Animals ; Atherosclerosis/metabolism* ; Signal Transduction/drug effects* ; Drugs, Chinese Herbal/administration & dosage* ; Mice ; Mice, Inbred C57BL ; Male ; Transforming Growth Factor beta/genetics* ; Humans ; Homeostasis/drug effects* ; Aorta/metabolism* ; Smad2 Protein/genetics* ; Smad3 Protein/genetics*

This article explored the specific mechanism by which ginsenoside Rg_1 regulates cellular autophagy to attenuate hypoxia/reoxygenation(H/R) injury in HL-1 cardiomyocytes through the microRNA155(miR-155)/neurogenic gene Notch homologous protein 1(Notch1)/hairy and enhancer of split 1(Hes1) pathway. An HL-1 cell model with H/R injury was constructed, and ginsenoside Rg_1 and/or Notch1 inhibitor DAPT and miR-155 mimics were used to treat cells. Cell counting kit(CCK)-8 was used to detect the relative viability of HL-1 cells with H/R injury. The lactate dehydrogenase(LDH) content in cell culture medium supernatant was detected by using an LDH assay kit, and autophagosome in cells was observed by transmission electron microscopy. The level of autophagy in cells was detected through the mono-dansyl-cadaverine(MDC) detection method. Fluorescence quantitative polymerase chain reaction was used to detect the mRNA levels of miR-155, Notch1, Hes1, and microtubule-associated protein1 light chain 3(LC3), and Western blot was used to detect the protein expression levels of Notch1, Hes1, LC3Ⅰ, and LC3Ⅱ. The results show that after H/R injury, the activity of HL-1 cells decreases, and LDH leakage increases. Besides, the number of intracellular autophagosomes increases, and the mRNA level of LC3 and the LC3Ⅱ/LC3Ⅰ ratio are elevated. In addition, ginsenoside Rg_1 can increase cell activity, decrease LDH leakage and the number of intracellular autophagosomes, and reduce the mRNA level of LC3 and the LC3Ⅱ/LC3Ⅰ ratio. Therefore, it plays a cardioprotective role by inhibiting autophagy, and Notch1 inhibitor or miR-155 overexpression can inhibit the effect of ginsenoside Rg_1, promote autophagy, and aggravate H/R injury in HL-1 cells. Ginsenoside Rg_1 can inhibit the reduction of Notch1 and Hes1 mRNA levels and protein expressions and the increase in miR-155 mRNA levels caused by H/R injury, while Notch1 inhibitors or miR-155 overexpression show the opposite effect. In summary, ginsenoside Rg_1 can regulate autophagy through the miR-155/Notch1/Hes1 pathway to alleviate H/R injury in HL-1 cardiomyocytes.
Ginsenosides/pharmacology* ; MicroRNAs/metabolism* ; Autophagy/drug effects* ; Receptor, Notch1/genetics* ; Transcription Factor HES-1/genetics* ; Mice ; Animals ; Cell Line ; Signal Transduction/drug effects* ; Myocytes, Cardiac/cytology* ; Cell Hypoxia/drug effects*

OBJECTIVE: To investigate the effect of Yinlai Decoction (YD) on the microstructure of colon, and activity of D-lactic acid (DLA) and diamine oxidase (DAO) in serum of pneumonia mice model fed with high-calorie and high-protein diet (HCD). METHODS: Sixty male Kunming mice were randomly divided into 6 groups by the random number table method: normal control, pneumonia, HCD, HCD with pneumonia (HCD-P), YD (229.2 mg/mL), and dexamethasone (15.63 mg/mL) groups, with 10 in each group. HCD mice were fed with 52% milk solution by gavage. Pneumonia mice was modeled with lipopolysaccharide inhalation and was fed by gavage with either the corresponding therapeutic drugs or saline water, twice daily, for 3 days. After hematoxylin-eosin staining, the changes in the colon structure were observed under light microscopy and transmission electron microscope, respectively. Enzyme-linked immunosorbent assay was used to detect the protein levels of DLA and DAO in the serum of mice. RESULTS: The colonic mucosal structure and ultrastructure of mice in the normal control group were clear and intact. The colonic mucosal goblet cells in the pneumonia group tended to increase, and the size of the microvilli varied. In the HCD-P group, the mucosal goblet cells showed a marked increase in size with increased secretory activity. Loose mucosal epithelial connections were also observed, as shown by widened intercellular gaps with short sparse microvilli. These pathological changes of intestinal mucosa were significantly reduced in mouse models with YD treatment, while there was no significant improvement after dexamethasone treatment. The serum DLA level was significantly higher in the pneumonia, HCD, and HCD-P groups as compared with the normal control group (P<0.05). Serum DLA was significantly lower in the YD group than HCD-P group (P<0.05). Moreover, serum DLA level significantly increased in the dexamethasone group as compared with the YD group (P<0.01). There was no statistical significance in the serum level of DAO among groups (P>0.05). CONCLUSIONS YD can protect function of intestinal mucosa by improving the tissue morphology of intestinal mucosa and maintaining integrity of cell connections and microvilli structure, thereby reducing permeability of intestinal mucosa to regulate the serum levels of DLA in mice.
Mice ; Male ; Animals ; Lactic Acid/pharmacology* ; Intestinal Mucosa ; Colon/pathology* ; Dexamethasone/pharmacology* ; Diet, High-Protein ; Pneumonia/pathology*

AIM: To analyze the correlation between SLC52A2 and uveal melanoma(UM)based on the cancer genome atlas(TCGA)database, and preliminarily explore the influence of SLC52A2 on the prognosis of UM patients and potential mechanism.METHODS: The clinical information on 80 patients with UM and mRNA expression data of SLC52A2 were collected from TCGA database. According to the expression level of SLC52A2, 80 patients were divided into high and low expression groups by median method. The relationship between the expression of SLC52A2 and clinical pathological features, as well as the prognosis was analyzed. The age, sex, clinical stage, pathological stage, and mRNA expression of SLC52A2 were analyzed by univariate and multivariate Cox analysis to search the prognostic factors of UM. Enrichment analyses were used to predict the possible regulatory pathway of SLC52A2 in UM.RESULTS: The survival prognosis of patients with low expression of SLC52A2 was better than that of patients with high expression of SLC52A2(P<0.05). The level of SLC52A2 has no significant correlation with the age, sex, clinical stage, and pathological stage of patients in both groups(P>0.05). Multivariate Cox analysis showed that the high expression of SLC52A2 was a risk factor for poor prognosis. The nomogram prediction model developed by combining the expression of SLC52A2 with clinical pathological features could accurately predict the survival probability of UM patients. The infiltration abundance of Th2 and Treg cells in both groups has difference(all P<0.001). GSEA analysis showed that the gene of JAK-STAT(FDR=0.028, P=0.004)and PI3K/AKT(FDR=0.017, P=0.002)were rich in samples with high expression of SLC52A2.CONCLUSION: The high expression of SLC52A2 is a risk factor for the prognosis of UM patients. SLC52A2 can be used as a biomarker to predict the prognosis and to become a new target for the treatment of patients with UM.

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34⁺⁰ weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.
Infant ; Infant, Newborn ; Humans ; Birth Weight ; Intensive Care Units, Neonatal ; Retrospective Studies ; Tertiary Care Centers ; Infant, Extremely Low Birth Weight ; Gestational Age ; Infant, Extremely Premature ; Sepsis/epidemiology* ; Retinopathy of Prematurity/epidemiology* ; Bronchopulmonary Dysplasia/epidemiology*