1.Sesquiterpene ZH-13 from Aquilariae Lignum Resinatum Improves Neuroinflammation by Regulating JNK Phosphorylation
Ziyu YIN ; Yun GAO ; Junjiao WANG ; Weigang XUE ; Xueping PANG ; Huiting LIU ; Yunfang ZHAO ; Huixia HUO ; Jun LI ; Jiao ZHENG
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(1):139-145
ObjectiveTo study the pharmacological substances and mechanisms through which sesquiterpene ZH-13 from Aquilariae Lignum Resinatum improves neuroinflammation. MethodsBV-2 microglial cells were stimulated with lipopolysaccharide (LPS) to induce neuroinflammation. The cells were divided into the normal group, the model group, and the ZH-13 low- and high-dose treatment groups (10, 20 μmol·L-1). The model group was treated with 1 μmol·L-1 LPS. Cell viability was assessed using the cell proliferation and activity assay (CCK-8 kit). Nitric oxide (NO) release in the cell supernatant was measured using a nitric oxide kit (Griess method). The mRNA expression levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and interleukin-6 (IL-6) were detected by real-time fluorescence quantitative polymerase chain reaction (Real-time PCR). The phosphorylation of mitogen-activated protein kinase (MAPK) pathway proteins was assessed by Western blot. ResultsCompared with the model group, ZH-13 dose-dependently reduced NO release from BV-2 cells under LPS stimulation (P<0.05, P<0.01). In the 20 μmol·L-1 ZH-13 treatment group, the mRNA expression levels of IL-1β, TNF-α, iNOS, and IL-6 were significantly reduced compared to the model group (P<0.05, P<0.01). In both the low- and high-dose ZH-13 groups, the expression of the inflammatory factor TNF-α and the phosphorylation of c-Jun N-terminal kinase (JNK) in the upstream MAPK pathway were significantly reduced (P<0.05). After stimulation with the JNK agonist anisomycin (Ani), both low- and high-dose ZH-13 treatment groups showed reduced phosphorylation of JNK proteins compared to the Ani-treated group (P<0.01). ConclusionThe sesquiterpene compound ZH-13 from Aquilariae Lignum Resinatum significantly ameliorates LPS-induced neuroinflammatory responses in BV-2 cells by inhibiting excessive JNK phosphorylation and reducing TNF-α expression. These findings elucidate the pharmacological substances and mechanisms underlying the sedative and calming effects of Aquilariae Lignum Resinatum.
2.Sesquiterpenoids from resin of Commiphora myrrha.
Hao HUANG ; Ran WANG ; Ya-Zhu YANG ; Jiao-Jiao YIN ; Yue LIN ; Yun-Fang ZHAO ; Hui-Xia HUO ; Jun LI
China Journal of Chinese Materia Medica 2025;50(3):702-707
The chemical constituents of Commiphora myrrha was investigated by column chromatography on silica gel, ODS, Sephadex LH-20, and semi-preparative HPLC. Their structures were elucidated by comprehensive spectroscopic methods including UV, IR, MS, NMR, as well as ECD calculation. Seven compounds were isolated from the dichloromethane-soluble fraction of C. myrrha and their structures were identified as(1S,2R,4S,5R,8S)-guaiane-2-hydroxy-7(11),10(15)-dien-6-oxo-12,8-olide(1), commipholide E(2), myrrhterpenoid H(3), myrrhterpenoid I(4), myrrhterpenoid E(5), 2α-methoxy-8α-hydroxy-6-oxogermacra-1(10),7(11)-dien-8,12-olide(6), 8,12-epoxy-1α,9α-hydroxy-eudesma-7,11-diene-6-dione(7). Compound 1 was a new compound and named myrrhterpenoid P. Compound 7 was isolated from Commiphora genus for the first time. Compounds 2, 5, and 6 significantly inhibited nitric oxide(NO) production in LPS-stimulated RAW264.7 cells, with IC_(50) values of(49.67±4.16),(40.80±1.27),(47.22±0.87) μmol·L~(-1), respectively [indomethacin as the positive control, with IC_(50) value of(63.92±2.60) μmol·L~(-1)].
Commiphora/chemistry*
;
Animals
;
Mice
;
Resins, Plant/chemistry*
;
Sesquiterpenes/isolation & purification*
;
Molecular Structure
;
Nitric Oxide
;
Macrophages/metabolism*
;
RAW 264.7 Cells
;
Drugs, Chinese Herbal/pharmacology*
3.Structural identification for in vivo metabolites of proanthocyanidin B_2.
Wen-Hui ZHAO ; Hui-Ting TANG ; Jun LI ; Yue-Lin SONG ; Ke ZHANG ; Yun-Fang ZHAO
China Journal of Chinese Materia Medica 2025;50(10):2841-2852
Proanthocyanidin B_2(PAC-B_2), a polyphenolic dimeric compound comprising two epicatechin molecules linked by a C-C bond, is extensively found in traditional Chinese medicines, with anti-tumor and anti-oxidant activities. Given the limited bioavailability, a thorough investigation and comprehensive understanding of PAC-B_2 metabolism in vivo are essential for elucidating therapeutic forms and mechanisms. In the present study, ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) in the negative ion mode was employed to acquire the MS/MS information of PAC-B_2 and metabolites in urine and feces samples of the rats administrated with PAC-B_2. Online energy-resolved MS(ER-MS) was applied as supplementary to obtain the full collision energy ramp-MS~2 spectra(FCER-MS~2) of isomers-of-interest, which implied comprehensive MS~2 information of targeted compounds. Finally, the possible metabolic pathways of PAC-B_2 in rats were proposed. The primary fragmentation behaviors of PAC-B_2 in the negative ion mode included quinone methide fission between C_4-C_8 bond, retro Diels-Alder cracking of F-ring, heterocyclic ring fission of C-ring, and neutral loss of small molecules such as H_2O. A total of 25 metabolites were tentatively elucidated in urine and feces samples of rats administrated with PAC-B_2 by fragmentation pattern and reported literature. Two groups of isomers, M3/M4/M5 and M9/M11, were confirmatively differentiated based on the relationships between optimal collision energy provided by FCER-MS~2 and bond properties, including bond length and bond dissociation energy. In addition to the ring-opening and methylation, PAC-B_2 could also be metabolized into epicatechin and low molecular weight phenolic acids, which were subsequently subjected to dehydroxylation, ring-opening, methylation, sulfation, and glucuronidation. The structural information provided by online ER-MS and FCER-MS~2 enabled the differentiation of isomers and improved the identification confidence. More importantly, the present study deeply analyzes the in vivo metabolic pathways of PAC-B_2, providing a basis for the research on the pharmacological mechanism of this compound.
Animals
;
Proanthocyanidins/urine*
;
Rats
;
Male
;
Drugs, Chinese Herbal/chemistry*
;
Rats, Sprague-Dawley
;
Tandem Mass Spectrometry
;
Chromatography, High Pressure Liquid
;
Feces/chemistry*
;
Molecular Structure
4.Three new chalcone C-glycosides from Carthami Flos.
Jia-Xu BAO ; Yong-Xiang WANG ; Xian ZHANG ; Ya-Zhu YANG ; Yue LIN ; Jiao-Jiao YIN ; Yun-Fang ZHAO ; Hui-Xia HUO ; Peng-Fei TU ; Jun LI
China Journal of Chinese Materia Medica 2025;50(13):3715-3745
The chemical components of Carthami Flos were investigated by using macroporous resin, silica gel column chromatography, reversed-phase octadecylsilane(ODS) column chromatography, Sephadex LH-20, and semi-preparative high-performance liquid chromatography(HPLC). The planar structures of the compounds were established based on their physicochemical properties and ultraviolet-visible(UV-Vis), infrared(IR), high-resolution electrospray ionization mass spectrometry(HR-ESI-MS), and nuclear magnetic resonance(NMR) spectroscopic technology. The absolute configurations were determined by comparing the calculated and experimental electronic circular dichroism(ECD). Six flavonoid C-glycosides were isolated from the 30% ethanol elution fraction of macroporous resin obtained from the 95% ethanol extract of Carthami Flos, and identified as saffloquinoside F(1), 5-hydroxysaffloneoside(2), iso-5-hydroxysaffloneoside(3), isosafflomin C(4), safflomin C(5), and vicenin 2(6). Among these, the compounds 1 to 3 were new chalcone C-glycosides. The compounds 1, 2, 4, and 5 could significantly increase the viability of H9c2 cardiomyocytes damaged by oxygen-glucose deprivation/reoxygenation(OGD/R) at a concentration of 50 μmol·L~(-1), showing their good cardioprotective activity.
Glycosides/pharmacology*
;
Flowers/chemistry*
;
Drugs, Chinese Herbal/pharmacology*
;
Carthamus tinctorius/chemistry*
;
Chalcones/pharmacology*
;
Animals
5.Application of oblique lateral interbody fusion channel technique in lumbar infection.
Sheng-Yun LI ; Jun LI ; Xiao-Rui ZHANG ; Jie SONG ; Xiu-Lei XU ; Kai LYU ; Xing ZHAO
China Journal of Orthopaedics and Traumatology 2025;38(5):473-481
OBJECTIVE:
To investigate the efficacy and safety of oblique lateral interbody fusion(OLIF) channel technique combined with pedicle screw internal fixation in the treatment of single-segment lumbar intervertebral space/vertebral body infection.
METHODS:
A retrospective analysis was conducted on 23 patients who underwent surgical treatment for lumbar infection from January 2021 to December 2022. The patients were divided into the OLIF channel group and the traditional open surgery group according to the surgical methods. There were 16 cases in the OLIF channel group, including 9 males and 7 females, with an average age of (68.5±12.1) years old;there were 7 cases in the traditional open surgery group, including 4 males and 3 females, with an average age of (75.0±3.2) years old. The operation time, intraoperative blood loss, hospital stay, incision length, visual analogue scale(VAS), activities of daily living (ADL) score, Oswestry disability index (ODI), erythrocyte sedimentation rate(ESR), C-reactive protein(CRP) before and 1 week and 3 months after the operation, and the intervertebral fusion status on the last follow-up CT were compared between the two groups.
RESULTS:
Compared with the open surgery group, the OLIF channel group had shorter operation time (209.87±31.5) min vs. (246.0±42.7) min, less intraoperative blood loss (225.625±91.1) ml vs. (364.2±74.8) ml, and shorter incision length (6.1±1.2) vs. (14.0±1.4) cm, and the differences were statistically significant(P<0.05). Before and 1 week and 3 months after the operation, the lumbar VAS in the OLIF group were (6.3±0.6), (2.8±0.7), (1.1±0.5), and those in the traditional open surgery group were (6.4±0.6), (3.4±0.5), (1.2±0.3);the ADL scores in the OLIF group were (45.0±4.5), (60.3±4.3), (94.1±4.2), and those in the open group were (46.4±5.6), (60.7±4.5), (92.9±4.9); the ODI scores in the OLIF group were (86.3±2.9)%, (69.5±4.1)%, (23.0±3.2)%, and those in the open group were (87.3±3.8)%, (69.8±4.2)%, (23.8±3.6)%, all of which showed significant improvement(P<0.05). Three months after the operation, CRP, PCT, and ESR were significantly lower than those before the operation, and CRP and PCT returned to normal, while ESR was still slightly elevated in some patients. The last follow-up CT showed that continuous trabecular bone formation was observed between the upper and lower endplates of the surgical segments in all patients, and the fusion time was (8.7±4.5) months.
CONCLUSION
The OLIF channel technique combined with posterior internal fixation is a minimally invasive and effective treatment method, which can effectively control infection, relieve pain, and improve the quality of life of patients. Compared with traditional open surgery, it has the advantages of minimally invasive, shorter operation time, and less intraoperative blood loss.
Humans
;
Male
;
Female
;
Spinal Fusion/methods*
;
Lumbar Vertebrae/microbiology*
;
Aged
;
Middle Aged
;
Retrospective Studies
;
Aged, 80 and over
;
Pedicle Screws
;
Infections/surgery*
6.Biomechanical study and clinical application of two osteotomy guide methods in media open wedge high tibial osteotomy operation.
Chao QI ; Xiao-Ming LI ; Dong-Hui GUO ; Qiu-Ling SHI ; Yun-Chao ZHAO ; Jun DONG ; Zheng-Xin MENG ; Xing-Yue WANG
China Journal of Orthopaedics and Traumatology 2025;38(7):698-704
OBJECTIVE:
To explore the effectiveness and feasibility of two osteotomy guides in medial open wedge high tibial osteotomy (MOWHTO).
METHODS:
Clinical data of 103 patients who underwent routine MOWHTO surgery between January 2020 and December 2022 were collected for retrospective analysis. The patients were divided into two groups based on the method of osteotomy guide plate. The control group of 51 patients received traditional osteotomy guide plate technique, including 17 males and 34 females, aged from 48 to 68 years old with an average of(57.93±4.82) years old, with a disease duration ranged from 1 to 8 years with an average of (4.89±1.49) years. The observation group of 52 patients received personalized osteotomy guide plate technique, including 23 males and 29 females, aged from 48 to 69 with an average of (58.22±5.10) years, with a disease duration ranged from 1 to 9 years with an average of(5.10±1.55) years. The perioperative indicators, complications, and knee joint recovery rate were statistically analyzed for both groups, as well as the preoperative and postoperative coagulation function, fibrinogen (FIB), D-dimer (D-D), gait parameters (step frequency, step length, step speed), biomechanical indicators, weight bearing line (WBL), medial proximal tibial angle (MPTA), joint line conergence angle (JLCA), and anterior cruciate ligament (ACL) function (body width, tibial anterior displacement).
RESULTS:
All patients were followed up for 6 months. The intraoperative blood loss, operation time, and number of fluoroscopic views in the observation group were (358.58±93.76) ml, (84.42±8.17) min, and (2.00±0.44) times, respectively, which were all less than those in the control group (465.55±105.38) ml, (96.53±10.51) min, and (6.31±0.58) times (P<0.05). Three days after surgery, the FIB and D-D levels in the observation group were (4.21±0.48) g·L-1 and (204.47±35.59) μg·L-1, respectively, which were both lower than those in the control group (5.56±0.57) g·L-1 and (311.12±42.23) μg·L-1 (P<0.05). Three months after surgery, the step frequency, step length, and step speed in the observation group were (1.89±0.23) steps·s-1, (0.57±0.15) m, and (0.99±0.11) m·s-1, respectively, which were all higher than those in the control group (1.80±0.18) steps·s-1, (0.50±0.14) m, and (0.95±0.09) m·s-1 (P<0.05). Three months after surgery, the WBL and MPTA in the observation group were (45.53±4.41)% and (87.03±8.15)°, respectively, which were both higher than those in the control group (38.38±4.36)% and (83.68±8.50)°, and the JLCA was (2.36±0.24)°, which was lower than that in the control group (2.61±0.33)° (P<0.05). The ACL body width during internal fixation removal was (5.60±0.51) mm, which was greater than that in the control group (5.08±0.56) mm, and the tibial migration was (5.70±0.42) mm, which was less than that in the control group (6.33±0.48) mm (P<0.05). There was no significant difference in the incidence of complications between the two groups (P>0.05). Six months after surgery, there was no significant difference in the recovery rate of knee joint between the two groups (P>0.05).
CONCLUSION
The application of personalized osteotomy guide technique in MOWHTO can help improve knee biomechanics and ACL function, and has less effect on coagulation function and no increase in complications.
Humans
;
Male
;
Female
;
Osteotomy/methods*
;
Middle Aged
;
Tibia/physiopathology*
;
Aged
;
Biomechanical Phenomena
;
Retrospective Studies
;
Osteoarthritis, Knee/physiopathology*
7.Visual analysis of dynamics and hotspots of biomechanics research on diabetic foot based on WoSCC.
Zhe WANG ; Wei-Dong LIU ; Jun LU ; Hong-Mou ZHAO ; Xue-Fei CAO ; Yun-Long ZHANG ; Xin CHANG ; Liang LIU
China Journal of Orthopaedics and Traumatology 2025;38(9):902-909
OBJECTIVE:
To explore the current research status and hotspots in the field of biomechanics of diabetic foot by bibliometric analysis methods.
METHODS:
Literatures related to biomechanics of diabetic foot published in the Web of Scienc Core Collection (WoSCC) from 1981 to 2024 were searched. CiteSpace software and R language bibliometrics plugin were used to conduct a visual analysis of annual publication volume of the literature, including publication volume of each country and region, the publication situation of authors and institutions, the citation situation of individual literature, and the co-occurrence network of keywords.
RESULTS:
Totally 996 literatures were included, and the number of published papers increased steadily. The United States (261 papers) and China (89 papers) were the top two countries in terms of the number of published papers. The mediating centrality of the United States was 0.94, and that of China was 0.01. Scholars such as Cavanagh and institutions like the Cleveland Clinic were at the core of research in this field. High-frequency keywords include plantar pressure (plantar pressure), diabetic foot (diabetic foot), ulceration (ulcer), etc. The research focuses on plantar pressure, ulcer formation and prevention, etc.
CONCLUSION
Biomechanical research on diabetic foot mainly focuses on the pressure distribution on the sole of the foot, callus formation, mechanical analysis of soft tissues on the sole of the foot, and the study of plantar decompression caused by Achilles tendon elongation. The research trend has gradually shifted from focusing on joint range of motion to gait and the design of braces and assistive devices, and has begun to pay attention to muscle strength, gait imbalance and proprioception abnormalities.
Humans
;
Diabetic Foot/physiopathology*
;
Biomechanical Phenomena
;
Bibliometrics
8.Analysis of risk factors, pathogenic bacteria characteristics, and drug resistance of postoperative surgical site infection in adults with limb fractures.
Yan-Jun WANG ; Zi-Hou ZHAO ; Shuai-Kun LU ; Guo-Liang WANG ; Shan-Jin MA ; Lin-Hu WANG ; Hao GAO ; Jun REN ; Zhong-Wei AN ; Cong-Xiao FU ; Yong ZHANG ; Wen LUO ; Yun-Fei ZHANG
Chinese Journal of Traumatology 2025;28(4):241-251
PURPOSE:
We carried out the study aiming to explore and analyze the risk factors, the distribution of pathogenic bacteria, and their antibiotic-resistance characteristics influencing the occurrence of surgical site infection (SSI), to provide valuable assistance for reducing the incidence of SSI after traumatic fracture surgery.
METHODS:
A retrospective case-control study enrolling 3978 participants from January 2015 to December 2019 receiving surgical treatment for traumatic fractures was conducted at Tangdu Hospital of Air Force Medical University. Baseline data, demographic characteristics, lifestyles, variables related to surgical treatment, and pathogen culture were harvested and analyzed. Univariate analyses and multivariate logistic regression analyses were used to reveal the independent risk factors of SSI. A bacterial distribution histogram and drug-sensitive heat map were drawn to describe the pathogenic characteristics.
RESULTS:
Included 3978 patients 138 of them developed SSI with an incidence rate of 3.47% postoperatively. By logistic regression analysis, we found that variables such as gender (males) (odds ratio (OR) = 2.012, 95% confidence interval (CI): 1.235 - 3.278, p = 0.005), diabetes mellitus (OR = 5.848, 95% CI: 3.513 - 9.736, p < 0.001), hypoproteinemia (OR = 3.400, 95% CI: 1.280 - 9.031, p = 0.014), underlying disease (OR = 5.398, 95% CI: 2.343 - 12.438, p < 0.001), hormonotherapy (OR = 11.718, 95% CI: 6.269 - 21.903, p < 0.001), open fracture (OR = 29.377, 95% CI: 9.944 - 86.784, p < 0.001), and intraoperative transfusion (OR = 2.664, 95% CI: 1.572 - 4.515, p < 0.001) were independent risk factors for SSI, while, aged over 59 years (OR = 0.132, 95% CI: 0.059 - 0.296, p < 0.001), prophylactic antibiotics use (OR = 0.082, 95% CI: 0.042 - 0.164, p < 0.001) and vacuum sealing drainage use (OR = 0.036, 95% CI: 0.010 - 0.129, p < 0.001) were protective factors. Pathogens results showed that 301 strains of 38 species of bacteria were harvested, among which 178 (59.1%) strains were Gram-positive bacteria, and 123 (40.9%) strains were Gram-negative bacteria. Staphylococcus aureus (108, 60.7%) and Enterobacter cloacae (38, 30.9%) accounted for the largest proportion. The susceptibility of Gram-positive bacteria to Vancomycin and Linezolid was almost 100%. The susceptibility of Gram-negative bacteria to Imipenem, Amikacin, and Meropenem exceeded 73%.
CONCLUSION
Orthopedic surgeons need to develop appropriate surgical plans based on the risk factors and protective factors associated with postoperative SSI to reduce its occurrence. Meanwhile, it is recommended to strengthen blood glucose control in the early stage of admission and for surgeons to be cautious and scientific when choosing antibiotic therapy in clinical practice.
Humans
;
Surgical Wound Infection/epidemiology*
;
Male
;
Female
;
Risk Factors
;
Retrospective Studies
;
Middle Aged
;
Adult
;
Case-Control Studies
;
Fractures, Bone/surgery*
;
Aged
;
Drug Resistance, Bacterial
;
Logistic Models
;
Anti-Bacterial Agents/therapeutic use*
;
Incidence
;
Bacteria/drug effects*
9.Pharmacological actions of the bioactive compounds of Epimedium on the male reproductive system: current status and future perspective.
Song-Po LIU ; Yun-Fei LI ; Dan ZHANG ; Chun-Yang LI ; Xiao-Fang DAI ; Dong-Feng LAN ; Ji CAI ; He ZHOU ; Tao SONG ; Yan-Yu ZHAO ; Zhi-Xu HE ; Jun TAN ; Ji-Dong ZHANG
Asian Journal of Andrology 2025;27(1):20-29
Compounds isolated from Epimedium include the total flavonoids of Epimedium , icariin, and its metabolites (icaritin, icariside I, and icariside II), which have similar molecular structures. Modern pharmacological research and clinical practice have proved that Epimedium and its active components have a wide range of pharmacological effects, especially in improving sexual function, hormone regulation, anti-osteoporosis, immune function regulation, anti-oxidation, and anti-tumor activity. To date, we still need a comprehensive source of knowledge about the pharmacological effects of Epimedium and its bioactive compounds on the male reproductive system. However, their actions in other tissues have been reviewed in recent years. This review critically focuses on the Epimedium , its bioactive compounds, and the biochemical and molecular mechanisms that modulate vital pathways associated with the male reproductive system. Such intrinsic knowledge will significantly further studies on the Epimedium and its bioactive compounds that protect the male reproductive system and provide some guidances for clinical treatment of related male reproductive disorders.
Male
;
Epimedium/chemistry*
;
Humans
;
Genitalia, Male/drug effects*
;
Flavonoids/therapeutic use*
;
Animals
10.Identification of Rare 3.5 kb Deletion in the β-Globin Gene Cluster.
Yun-Hua FAN ; Cui-Lin DUAN ; Sai-Li LUO ; Shi-Jun GE ; Chong-Fei YU ; Jue-Min XI ; Jia-You CHU ; Zhao-Qing YANG
Journal of Experimental Hematology 2025;33(1):175-179
OBJECTIVE:
To identify the gene mutation types of 4 suspected β-thalassemia patients in Yunnan Province, and to analyze the genotypes and hematological phenotypes.
METHODS:
Whole genome sequencing was performed on the samples of 4 suspected β-thalassemia patients from the Dai ethnic group in a thalassemia endemic area of Yunnan Province, whose hematological phenotypes were not consistent with the results of common thalassemia gene mutations. The mutations of β-globin gene clusters were confirmed by polymerase chain reaction (PCR) and Sanger DNA sequencing technology.
RESULTS:
The 3.5 kb deletion in β-globin gene cluster (NC_000011.10: g. 5224302-5227791del3490bp) was detected in 4 patients' samples, of which 1 case was also detected with HbE mutation and 1 case with CD17 mutation. These 2 patients displayed moderate anemia phenotype, while the two patients with only the 3.5 kb deletion presented with other mild anemia phenotype.
CONCLUSION
Heterozygous carriers with rare 3.5 kb deletion of the β-globin gene cluster may develop mild anemia, compound mutations of the 3.5 kb deletion with other mutations may led to intermediate thalasemia with moderate to sever anemia. In areas with a high incidence of thalassemia, suspected patients should undergo genetic testing to avoid missing or misdiagnosing rare mutations.
Humans
;
beta-Globins/genetics*
;
Multigene Family
;
beta-Thalassemia/genetics*
;
Mutation
;
Genotype
;
Sequence Deletion
;
Phenotype
;
Male
;
Female

Result Analysis
Print
Save
E-mail