1.From Cathartic Colon to Cathartic-dependent Constipation: Diagnostic-therapeutic Strategies from Integrative Medicine Perspective
Youcheng HE ; Fengru JIANG ; Yanru WANG ; Minghan HUANG ; Yue WU ; Chunyu ZHOU ; Lian MO ; Lifeng WEI ; Keyi PAN ; Shuyu CAI ; Jianye YUAN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(11):162-172
Both cathartic colon (CC) and cathartic-dependent constipation (CDC) are caused by the abuse of stimulant laxatives, while their concepts are not completely the same.Starting from the disease name of CC, this article traced the origin and evolution of the concept of CC, summarizes and compared the similarities and differences between CC, CDC, and slow transit constipation (STC), and called for strict differentiation among the three.Furthermore, this article explored the specific contents of Western medicine clinical subtypes and traditional Chinese medicine (TCM) syndrome differentiation of CDC and delved into the TCM pathogenesis of CDC according to both literature and clinical practice.The relationship between clinical subtypes and TCM syndromes was established, and the syndrome characteristics of CDC of different clinical subtypes and TCM syndromes were summarized.The recommended prescriptions for corresponding syndromes were listed.A systematic CDC diagnosis and treatment approach of "clinical subtypes-syndrome differentiation-syndrome characteristics-recommended prescriptions" was thus formed.Additionally, the paper provides an overview of current research on CDC in both Western medicine and TCM contexts, identifies future research directions, and suggests research pathways for refining and advancing CDC studies.
2.Clinical Efficacy of Yiqi Yangyin Huoxue Prescription in Treatment of Cathartic Colon and Analysis of Influencing Factors of Disease Severity
Youcheng HE ; Jingyi SHAN ; Fengru JIANG ; Yue WU ; Chunyu ZHOU ; Lu HANG ; Yan ZHOU ; Lian MO ; Shuyu CAI ; Keyi PAN ; Lifeng WEI ; Jianye YUAN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(11):173-184
ObjectiveTo observe the clinical efficacy of the Yiqi Yangyin Huoxue prescription (YYHP) in the treatment of cathartic colon (CC) and its effects on fecal short-chain fatty acids (SCFAs), and to explore the correlations among CC severity indicators and between these indicators and patient history. MethodsAccording to the inclusion and exclusion criteria, 98 patients meeting the diagnostic criteria of both traditional Chinese and Western medicine for CC with the syndrome of Qi-Yin deficiency complicated by blood stasis were randomly assigned to an observation group and a control group. The observation group received YYHP granules, while the control group received lactulose. Both medications were administered twice daily, one sachet each time, half an hour after breakfast and dinner, with a treatment course of 8 weeks. The primary constipation symptom score, Patient Assessment of Constipation Quality of Life (PAC-QOL) score, and TCM syndrome score were assessed before and after treatment and at the 8th week after the end of treatment. The overall clinical effective rate, as well as the efficacy attenuation index and degree, were evaluated. Fecal SCFA levels were measured using gas chromatography-mass spectrometry (GC-MS). Spearman correlation analysis was performed to explore the correlations among CC severity indicators and between these indicators and patient history. ResultsThe overall clinical effective rate in the observation group (95.83%) was higher than that in the control group (78.72%) (P<0.05). After treatment, the total scores for primary constipation symptoms, PAC-QOL, and TCM syndromes decreased in both groups (P<0.05), with more significant reductions in the observation group (P<0.05). The severity of all primary constipation symptoms was alleviated in both groups (P<0.05). In terms of "excessive straining and difficult defecation", "anal heaviness, incomplete evacuation, and bloating sensation", "abdominal distension", and "defecation frequency", the observation group showed better efficacy than the control group (P<0.05). Scores of the four PAC-QOL dimensions and the scores and severity of primary and secondary TCM symptoms were reduced in both groups (P<0.05), with more significant reductions in the observation group (P<0.05). After treatment, acetic acid, propionic acid, butyric acid, and total SCFAs in the observation group increased significantly (P<0.05). The efficacy attenuation index and degree in the observation group were lower than those in the control group (P<0.05). No severe adverse reactions occurred in either group, and there was no statistically significant difference in the incidence of adverse reactions between the two groups. Positive correlations of varying degrees were observed among the total scores of primary constipation symptoms, PAC-QOL, and TCM syndromes, as well as between these scores and the history of stimulant laxative use, disease duration, and age. ConclusionYYHP can effectively alleviate the primary constipation symptoms in CC patients, improve quality of life, and ameliorate TCM syndromes, with good safety. It also has the advantage of a lower rebound degree after drug withdrawal, and its mechanism may be related to increasing fecal SCFA levels. Long-term abuse of stimulant laxatives may aggravate the severity of CC and prolong the disease course.
3.Qi and Yin Deficiency with Qi Stagnation and Blood Stasis in Rat Model of Rhein-induced Cathartic Colon
Youcheng HE ; Fengru JIANG ; Yue WU ; Chunyu ZHOU ; Erhao LIU ; Pengfei ZHOU ; Keyi PAN ; Shuyu CAI ; Jianye YUAN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(11):185-195
ObjectiveTo evaluate and analyze the syndrome characteristics of Qi and Yin deficiency accompanied by Qi stagnation and blood stasis in a rhein-induced cathartic colon (CC) rat model. MethodsTwenty-four rats were divided into a normal group and a model group (CC group). The rats were administered equal volumes of physiological saline or 2% rhein suspension by gavage to establish the model over three cycles (approximately 118 days). The first cycle lasted 46 days, with a dosage of 12 mL·kg-1·d-1, administered every other day. The second cycle lasted 37 days, with a dosage of 12 mL·kg-1·d-1, administered for 5 consecutive days followed by 2 days of cessation. The third cycle lasted 35 days, with a dosage of 16 mL·kg-1·d-1, also administered for 5 consecutive days followed by 2 days of cessation. Each cycle ended when 80% of the rats no longer exhibited loose stools. Body mass, 24 h food intake, coat condition, and coat red (R), green (G), and blue (B) values were recorded. The open field test (OFT) was used to measure the total distance traveled to evaluate Qi deficiency. The body mass coefficient and 24 h water intake were recorded to assess Yin deficiency. The sucrose preference test (SPT) was used to determine the sucrose preference rate (SPR), and the average speed in OFT was measured to evaluate depressive status (liver depression and Qi stagnation). Tongue images and their R, G, and B values were recorded. Whole blood viscosity (WBV) and plasma viscosity (PV) were measured using an automatic hemorheological analyzer to evaluate blood stasis. A carbon ink propulsion test was performed to determine the intestinal transit rate (ITR) for disease model evaluation. Hematoxylin-eosin (HE) staining was used to observe histopathological changes in the colon. Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) was used to detect the mRNA expression of transient receptor potential ankyrin 1 (TRPA1) and tryptophan hydroxylase 1 (TPH1) in colon tissue. Western blot was used to detect the protein expression of TRPA1 and TPH1. ResultsIn terms of syndrome indicators, compared with the normal group, the body mass of the CC group decreased (P<0.05), while 24 h food intake increased (P<0.01). The coats of the CC group appeared withered, disheveled, and dull, and the R, G, and B values of the coat decreased (P<0.01). The total distance traveled in OFT decreased (P<0.01). The body mass coefficient decreased (P<0.01), while 24 h water intake increased (P<0.05, P<0.01). The SPR decreased (P<0.01), and the average speed in OFT slowed (P<0.01). The tongue appeared dark red, and the R, G, and B values of tongue images decreased (P<0.01). WBV and PV increased (P<0.01). Regarding disease indicators, compared with the normal group, the ITR decreased in the CC group (P<0.01). Pathologically, HE staining showed necrosis and shedding of colonic mucosal epithelial cells, disruption of mucosal continuity, and infiltration of inflammatory cells in the lamina propria in the CC group. Semi-quantitative analysis showed increased HAI scores (P<0.05) and increased inflammatory cell counts and area proportion (P<0.05). In terms of molecular biological indicators, compared with the normal group, the mRNA and protein expression levels of TRPA1 and TPH1 in colon tissue decreased in the CC group (P<0.05, P<0.01). ConclusionThe rhein-induced CC rat model conforms to the traditional Chinese medicine syndrome characteristics of Qi and Yin deficiency accompanied by Qi stagnation and blood stasis.
4.Research progress on the intervention of human umbilical cord mesenchymal stem cell in neurodegenerative disease
Hongcai XU ; Yumin XU ; Shiyu LIU ; Huayu YAN ; Yuan LIU ; Xin YANG ; Yabo WU
China Pharmacy 2026;37(3):395-400
Human umbilical cord mesenchymal stem cell (hUC-MSC) as a cell-based therapeutic strategy have demonstrated significant application potential in the field of intervention for neurodegenerative disease (NDD) due to their advantages such as self-renewal, multi-directional differentiation, and low immunogenicity. hUC-MSC effectively intervenes in the pathological features and neurological functions of various disease models such as Alzheimer disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis primarily through multiple mechanisms such as homing and differentiation, mediating paracrine actions and releasing exosomes, as well as immune regulation and anti-inflammation. Some clinical studies have also preliminarily verified their safety and effectiveness. Currently, its research still faces challenges such as immune rejection reactions requiring further observation, long-term safety needing evaluation, mechanisms of action not being fully elucidated, and slow progress in clinical trials. Future research needs to establish pharmaceutical standards for hUC-MSC, deepen their pharmacological mechanisms and clinical trials, ultimately providing new and effective drug treatment options for patients with NDD.
5.Comparison of clinical efficacy of evolocumab and probucol after PCI in patients with ultra-high-risk atherosclerotic cardiovascular disease
Yi YUAN ; Na LI ; Haiying SUN ; Jing SUN ; Yongqiang MA ; Yan WU ; Guohong YANG ; Junxiang LIU
China Pharmacy 2026;37(5):645-649
OBJECTIVE To compare the efficacy and safety of evolocumab and probucol in patients with ultra-high-risk atherosclerotic cardiovascular disease (ASCVD) following percutaneous coronary intervention (PCI). METHODS A retrospective analysis was conducted on 156 ultra-high-risk ASCVD patients who underwent PCI in our institution between January 1, 2023 and December 31, 2024. According to the lipid-lowering regimen, the patients were categorized into evolocumab group ( n =86) and probucol group ( n =70). Changes in lipid parameters [total cholesterol (TC), low-density lipoprot ein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, lipoprotein (a), and lipid goal achievement rate ] , inflammatory markers [interleukin-6 (IL-6) and C-reactive protein (CRP) ] , and cardiac function indices (left ventricular ejection fraction, left ventricular end-systolic diameter, left ventricular end-diastolic diameter, and N-terminal pro-B-type natriuretic peptide) were compared between two groups at baseline and after 6 months of treatment. The incidence of adverse clinical events during treatment, including acute myocardial infarction, in-stent restenosis, acute heart failure, cerebral hemorrhage, and stroke, was also evaluated. RESULTS No statistically significant differences were observed between the two groups at baseline ( P >0.05). After 6 months of treatment, both groups demonstrated significant improvements in lipid profiles (except HDL-C) and inflammatory markers compared to those at baseline ( P <0.05). The evolocumab group exhibited greater reductions in TC, LDL-C, IL-6, and CRP, along with a higher lipid target achievement rate, compared with the probucol group ( P <0.05). There were no statistically significant differences in the cardiac function-related indicators before and after treatment between the two groups, nor in the incidence of adverse events during the treatment ( P >0.05). CONCLUSIONS For ultra-high-risk ASCVD patients after PCI, both of the above treatment options are associated with improvements in blood lipid and inflammatory response, with good safety during short-term follow-up. Evolocumab shows superior efficacy in TC, LDL-C and inflammatory markers reduction and lipid target achievement, compared to probucol.
6.Patient fibrinogen management from a blood transfusion medicine perspective
Chixiang LIU ; Keyuan LAI ; Yuan YAO ; Kuncheng WANG ; Houmei FENG ; Qiusui MAI ; Yinmei LIAO ; Yingsong WU
Chinese Journal of Blood Transfusion 2026;39(2):265-276
From the perspective of transfusion medicine and based on the vision and framework of patient blood management, this article combines the advances in basic science, blood transfusion, laboratory, and clinical medicine. It aims to systematically review the key elements and characteristics of patient fibrinogen management by maintaining and optimizing patients' hemostatic function while reducing blood transfusions. This review enriches the connotation of transfusion medicine, especially patient blood management, and provides valuable insights for clinical practice.
7.Arterial switch operation under an integrated management mode of prenatal diagnosis-postnatal treatment for congenital heart disease: A single-center retrospective cohort study
Zirui PENG ; Jing LING ; Jiaxiong WU ; Runzhang LIANG ; Canxin WANG ; Jinxin LI ; Haiyun YUAN ; Shusheng WEN
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(03):415-423
Objective To evaluate the impact of an integrated management mode of prenatal diagnosis-postnatal treatment for congenital heart disease (CHD) on perioperative and long-term outcomes of the arterial switch operation (ASO), and to analyze the efficacy of ASO in a single center. Methods This retrospective study analyzed the clinical data of 183 children who underwent ASO at Guangdong Provincial People’s Hospital from 2018 to 2024. The cohort included 106 (57.9%) patients of transposition of the great arteries with intact ventricular septum (TGA/IVS), 61 (33.3%) patients of transposition of the great arteries with ventricular septal defect (TGA/VSD), and 16 (8.7%) patients of Taussig-bing anomaly (TBA). Perioperative indicators were compared between 91 patients in the prenatal-postnatal integrated management group (an integrated group) and 92 patients in the traditional management group (a non-integrated group). Long-term survival and reoperation rates were analyzed using Kaplan-Meier curves. Results The overall perioperative mortality rate was 4.9% (9/183), showing a downward trend year by year. The primary cause of perioperative mortality was low cardiac output syndrome (LCOS), which occurred in 12 patients (6.6% incidence) with a mortality rate of 75.0%. The integrated group had a higher proportion of males (89.0% vs. 72.8%, P<0.05) and lower body weight [3.1 (2.7, 3.3) kg vs. 3.3 (3.0, 3.7) kg, P<0.05] compared to the non-integrated group. The age at surgery was significantly earlier in the integrated group [7 (3, 10) d vs. 14 (9, 48) d, P<0.05], and all children in the integrated group underwent ASO within the optimal surgical window (100.0% vs. 82.6%, P<0.05). Intraoperatively, cardiopulmonary bypass time [173 (150, 207) min vs. 186 (159, 237) min, P<0.05] and aortic cross-clamp time [100 (90, 117) min vs. 116 (97, 142) min, P<0.05] were significantly shorter in the integrated group. Although the integrated group had longer postoperative mechanical ventilation time [145 (98, 214) h vs. 116 (77, 147) h, P<0.05] and higher 48-hour maximum vasoactive inotropic score [15 (10, 21) points vs. 12 (8, 16) points, P<0.05], there was no statistically significant difference in the incidence of severe complications (LCOS, necrotizing enterocolitis, extracorporeal membrane oxygenation) or mortality rate (3.3% vs. 6.5%, P=0.51) between the two groups, despite earlier surgical intervention and a higher proportion of critically ill cases in the integrated group. The length of hospital stay in the emergency surgery group was significantly shorter than that in the elective surgery group [20 (15, 28) d vs. 25 (21, 30) d, P<0.05], suggesting that early surgery may be of potential benefit. A total of 163 patients were successfully followed up for a median of 4.7 years, with a 5-year survival rate of 95.1% and a freedom from reintervention survival rate of 95.1%. There were no late deaths, and the most common postoperative complication was pulmonary artery stenosis. Conclusion The integrated management model allowed critically ill children with lower body weights to safely undergo surgery, significantly optimizing the timing of surgery and shortening intraoperative times. The long-term risk of reoperation after ASO is primarily concentrated on pulmonary artery stenosis, necessitating long-term follow-up and monitoring.
8.Mechanism of Xixintang in Protecting Blood-brain Barrier in Alzheimer's Disease Model Rats Based on AQP4 Polarization
Siyuan JIA ; Yongchang DIWU ; Yuan TIAN ; Jie GAO ; Meirong WU ; Dengkun WANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(9):1-10
ObjectiveThis paper aims to investigate the effects of Xixintang on aquaporin-4 (AQP4) polarity distribution, blood-brain barrier (BBB) function, and neuroinflammationin rats with Alzheimer's disease (AD), thereby revealing the potential mechanism through which this formula protects the BBB by regulating AQP4 polarization. The aim is to provide a scientific basis for clinical treatment. MethodsSixty Sprague-Dawley (SD) rats were randomly divided into a normal group, a model group, a probiotic group, a donepezil group, and an Xixintang group. The model was established by intraperitoneal injection of D-galactose (D-Gal) combined with bilateral intracerebroventricular injection of amyloid-β25-35 (Aβ25-35). The probiotic group (30.85 mg·kg-1), donepezil group (0.88 mg·kg-1), and Xixintang group (1.174 g·kg-1) received daily gavage administration, while the normal and model groups received intragastric administration with an equal volume of normal saline for one month. Cognitive ability was assessed by using the Morris water maze. BBB permeability was detected via Evans blue extravasation. The contents of interleukin-6 (IL-6), amyloid-β1-42 (Aβ1-42), and tumor necrosis factor-α (TNF-α) in the hippocampal tissues were measured by enzyme-linked immunosorbent assay (ELISA). The protein expressions of zonula occludens-1 (ZO-1), occludin, tissue inhibitor of metalloproteinase-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), and AQP4 in the hippocampal tissues were detected by western blot. The expression and co-localization levels of Aβ1-42, ionized calcium-binding adapter molecule 1 (IBA1), and AQP4/platelet endothelial cell adhesion molecule 31 (CD31) in the hippocampal region were examined by immunofluorescence. ResultsCompared with the normal group, the model group exhibited a significant decline in cognitive ability (P<0.01) and a marked increase in Evans blue extravasation in the brain (P<0.01). The expressions of ZO-1, occludin, and TIMP-1 were significantly decreased (P<0.01), while the expressions of AQP4 and MMP-9 were significantly increased (P<0.01). The co-localization level of AQP4/CD31 was significantly reduced (P<0.01), and the expressions of Aβ1-42, IL-6, TNF-α, and IBA1 were significantly elevated (P<0.01). Compared with the model group, the Xixintang group showed significant improvement in cognitive ability (P<0.01) and a significant reduction in Evans blue extravasation in the brain (P<0.01). The expressions of occludin, TIMP-1, and ZO-1 were significantly increased (P<0.05, P<0.01), while the expressions of AQP4 and MMP-9 were significantly decreased (P<0.05). The co-localization level of AQP4/CD31 was significantly enhanced (P<0.01), and the expressions of Aβ1-42, IL-6, TNF-α, and IBA1 were significantly reduced (P<0.05, P<0.01). ConclusionXixintang may improve cognitive function and alleviate AD pathology in AD model rats by regulating AQP4 polarity distribution, thereby breaking the vicious cycle of "Aβ deposition-neuroinflammation-BBB damage" and restoring the homeostasis of the microenvironment in the brain.
9.Syndrome Differentiation and Treatment of Asymptomatic Renal Hematuria Population Based on Association of Age-Constitution-Syndrome
Guangjian WANG ; Cong QIN ; Yibo WU ; Guodong YUAN ; Suzhi CHEN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(9):247-255
For a long time, simple asymptomatic renal hematuria has not been taken seriously. Current studies have confirmed that renal hematuria is a risk factor for the progression of renal function, but there is no effective treatment available. Because asymptomatic renal hematuria is highly concealed and lacks typical symptoms, individualized syndrome differentiation in traditional Chinese medicine (TCM) is difficult, making it a challenge in clinical diagnosis and treatment. Although TCM has a long history and solid theoretical basis in the treatment of hematuria, it urgently needs to break through the bottleneck of traditional syndrome differentiation. Based on classical TCM theories, research achievements in modern constitution studies, and relevant clinical and pathological evidence, this article focuses on the decisive influence of age on constitution distribution and its regular association with the evolution of core syndromes, and constructs a three-dimensional diagnostic and therapeutic system of "age-constitution-syndrome". It reveals that the syndrome manifestations of asymptomatic renal hematuria are profoundly shaped by constitution, and that constitution shows a group distribution pattern with age-children often present with deficiency of lung and spleen Qi combined with wind-heat, young and middle-aged individuals often present with deficiency of liver and kidney Yin combined with deficient fire and stasis heat, and elderly individuals often present with deficiency of spleen and kidney combined with cold-dampness and stasis obstruction. By analyzing the common pathogenic mechanisms, outcome characteristics, and internal mechanisms among different age groups, this study provides a basic syndrome framework and core intervention strategies for specific populations in clinical practice, offering a new evidence-based approach to addressing the dilemma of “no identifiable syndrome”.
10.Influencing factors for calcium salt deposition in patients with alveolar echinococcosis
Zitong XIONG ; Zhiyi LIN ; Yanxin HUANG ; Fuzhong FANG ; Zhengzhan WU ; Zirui XIN ; Chunxia HU ; Jiayu ZHOU ; Yuan YAO ; Hongwei ZHANG
Journal of Clinical Hepatology 2026;42(2):372-379
ObjectiveTo investigate the imaging features of calcium salt deposition and serological markers in patients with alveolar echinococcosis through a retrospective analysis, as well as independent risk factors for the degree of calcium salt deposition in lesions, and to provide a basis for assessing disease process. MethodsA retrospective analysis was performed for the imaging and clinical data of 107 patients with alveolar echinococcosis who were admitted to The First Affiliated Hospital of Shihezi University from December 2023 to June 2025, and according to the volume of calcium salt deposition, they were divided into non-deposition group with 16 patients, mild deposition group with 52 patients, moderate deposition group with 16 patients, and severe deposition group with 23 patients. A one-way analysis of variance or the Kruskal-Wallis H test was used for comparison of continuous data between groups, and the χ2 test or Fisher’s exact test was used for comparison of categorical data between groups. The four groups were further combined into the low deposition group (no/mild deposition) and the high deposition group (moderate/severe deposition). A binary logistic regression analysis was used to investigate the independent influencing factors for calcium salt deposition, and a predictive model was established. The receiver operating characteristic (ROC) curve was used to assess the predictive performance of the model, and the Bootstrap method was used for internal validation. ResultsThere were significant differences between the four groups in sex distribution, involvement of other sites, white blood cell count, lymphocyte percentage, fibrinogen, uric acid, sodium ion, chloride ion, and calcium ion (all P<0.05). The univariate analysis showed that there were significant differences between the four groups in sex, involvement of other sites, white blood cell count, lymphocyte percentage, fibrinogen, alanine aminotransferase, albumin, creatinine, uric acid, sodium ion, chloride ion, and calcium ion (all P<0.1). The multi-collinearity diagnosis showed that the VIF values for all continuous variables ranged from 1.104 to 1.760, suggesting that collinearity did not affect modeling. An ordinal logistic regression model was established based on sex, involvement of other sites, calcium ion, lymphocyte percentage, and uric acid. The multivariate analysis showed that lymphocyte percentage (odds ratio [OR]=1.106, 95% confidence interval [CI]: 1.041 — 1.174, P=0.001) and blood calcium level (OR=0.005, 95%CI: 0.000 —0.230, P=0.007) were independent influencing factors for the degree of calcium salt deposition. The regression equation was established as Logit(P)=8.231 + 0.100 × lymphocyte percentage -5.344 × calcium ion. The ROC curve analysis showed that the model had an area under the ROC curve of 0.716, with a Youden index of 0.353, a sensitivity of 1.000, and a specificity of 0.353. The Hosmer-Lemeshow test showed that the model had poor calibration (χ2=20.688, P=0.008). The Bootstrap method with 1000 repeated samples showed that the estimated values of lymphocyte percentage (OR=1.106, 95%CI: 1.049 — 1.186, P=0.002) and calcium ion (OR=0.005, 95%CI: 0.000 — 0.214, P=0.010) were consistent with the original model, and the confidence intervals did not include 1, which further supported the reliability of the model. ConclusionBoth lymphocyte percentage and blood calcium level are independent influencing factors for calcium salt deposition in alveolar echinococcosis, and the degree of calcium salt deposition in alveolar echinococcosis lesions increases with the reduction in blood calcium level and the increase in lymphocyte percentage.

Result Analysis
Print
Save
E-mail