A double signal amplification-based homogeneous electrochemical sensor built on catalytic hairpin assembly and bisferrocene markers.

A facile, sensitive and unmodified Hg2+ homogeneous electrochemical sensor based on bisferrocene signal markers and catalytic hairpin self-assembly (CHA) was built on a gold disk electrode. Three hairpin probes were designed, in which thiol was labeled at both ends of the hairpin probe 1(HP1), while bisferrocene, a redox signal marker, was labeled at both ends of the hairpin probe 2(HP2) and hairpin probe 3(HP3). Due to the Hg2+ mediated thymine-Hg (II)-thymine (T-Hg2+-T) structure, when Hg2+ is introduced, the T-Hg2+-T that occurred between the probe DNA and helper DNA could open the hairpin structure of probe DNA and form a rigid DNA triangles structure by CHA. Simultaneously, four bisferrocene signal markers also reached the surface of the electrode and built potential-assisted Au-S self-assembly to achieve signal amplification. Under the optimized condition, the sensor can achieve good electrochemical response Hg2+detection, and the detection limit is as low as 0.6 pM. furthermore, this sensor has high selectivity for Hg2+ detection.

Rate-limiting steps in the Saccharomyces cerevisiae ergosterol pathway: towards improved ergosta-5,7-dien-3ß-ol accumulation by metabolic engineering.

Ergosterol is the predominant nature sterol constituent of plasma membrane in Saccharomyces cerevisiae. Herein, the biosynthetic pathway of ergosterol was proposed to be metabolically engineered for the efficient production of ergosta-5,7-dien-3ß-ol, which is the precursor of vitamin D4. By target disruption of erg5, involved in the end-steps of post-squalene formation, predominantly accumulated ergosta-5,7-dien-3ß-ol (4.12 mg/g dry cell weight). Moreover, the rate-limiting enzymes of ergosta-5,7-dien-3ß-ol biosynthesis were characterized. Overexpression of Hmg1p led to a significant accumulation of squalene, and induction of Erg1p/Erg11p expression raised the yield of both total sterols and ergosta-5,7-dien-3ß-ol with no obvious changes in growth behavior. Furthermore, the transcription factor allele upc2-1 was overexpressed to explore the effect of combined induction of rate-limiting enzymes. Compared with an obviously enhanced yield of ergosterol in the wild-type strain, decreases of both the ergosta-5,7-dienol levels and the total sterol yield were found in Δerg5-upc2-1, probably due to the unbalanced NADH/NAD+ ratio observed in the erg5 knockouts, suggesting the whole-cell redox homeostasis was also vital for end-product biosynthesis. The data obtained in this study can be used as reference values for the production of sterol-related intermediates involved in the post-squalene biosynthetic pathway in food-grade S. cerevisiae strains.

Utility of deep learning for the diagnosis of cochlear malformation on temporal bone CT.

OBJECTIVE: Diagnosis of cochlear malformation on temporal bone CT images is often difficult. Our aim was to assess the utility of deep learning analysis in diagnosing cochlear malformation on temporal bone CT images. METHODS: A total of 654 images from 165 temporal bone CTs were divided into the training set (n = 534) and the testing set (n = 120). A target region that includes the area of the cochlear was extracted to create a diagnostic model. 4 models were used: ResNet10, ResNet50, SE-ResNet50, and DenseNet121. The testing data set was subsequently analyzed using these models and by 4 doctors. RESULTS: The areas under the curve was 0.91, 0.94, 0.93, and 0.73 in ResNet10, ResNet50, SE-ResNet50, and DenseNet121. The accuracy of ResNet10, ResNet50, and SE-ResNet50 is better than chief physician. CONCLUSIONS: Deep learning technique implied a promising prospect for clinical application of artificial intelligence in the diagnosis of cochlear malformation based on CT images.

Antibiotic prophylaxis for surgical wound infections in clean and clean-contaminated surgery: an updated systematic review and meta-analysis.

BACKGROUND: The efficacy and necessity of prophylactic antibiotics in clean and clean-contaminated surgery remains controversial. METHODS: The studies were screened and extracted using databases including PubMed, Embase, Cochrane Library, Web of Science, and Clinical Trials.gov according to predefined eligibility criteria. Randomized controlled trials (RCTs) comparing the effect of preoperative and postoperative prophylactic antibiotic use on the incidence of surgical site infections (SSIs) in patients undergoing any clean or clean-contaminated surgery. RESULTS: A total of 16 189 participants in 48 RCTs were included in the primary meta-analysis following the eligibility criteria. The pooled odds ratio (OR) for SSI with antibiotic prophylaxis versus placebo was 0.60 (95% CI: 0.53-0.68). The pooled OR among gastrointestinal, oncology, orthopedics, neurosurgery, oral, and urology surgery was 3.06 (95% CI: 1.05-8.91), 1.16 (95% CI: 0.89-1.50), 2.04 (95% CI: 1.09-3.81), 3.05 (95% CI: 1.25-7.47), 3.55 (95% CI: 1.78-7.06), and 2.26 (95% CI: 1.12-4.55), respectively. Furthermore, the summary mean difference (MD) for patients' length of hospitalization was -0.91 (95% CI: -1.61, -0.16). The results of sensitivity analyses for all combined effect sizes showed good stability. CONCLUSION: Antibiotics are both effective, safe, and necessary in preventing surgical wound infections in clean and clean-contaminated procedures, attributed to their reduction in the incidence of surgical site infections as well as the length of patient hospitalization.

Prevalence of depression, anxiety in China during the COVID-19 pandemic: an updated systematic review and meta-analysis.

Background: Mental health risks associated with the aftermath of the COVID-19 pandemic are often overlooked by the public. The aim of this study was to investigate the effects of the COVID-19 pandemic on depression and anxiety disorders in China. Methods: Studies were analyzed and extracted in accordance with the PRISMA 2020 flowchart. The studies were screened and extracted using electronic databases including PubMed, Web of Science, Embase, Cochrane Library, and ClinicalTrials.gov according to the predefined eligibility criteria. The Cochrane Review Manager software 5.3.1 was used for data analysis and the risk of bias assessment. Results: As of 2023, a total of 9,212,751 Chinese have been diagnosed with COVID-19 infection. A total of 913,036 participants in 44 studies were selected following the eligibility criteria, the statistical information of which was collected for meta-analysis. The pooled prevalence of depression and anxiety were 0.31 (95% CI: 0.28, 0.35; I2 = 100.0%, p < 0.001) and 0.29 (95% CI: 0.23, 0.36; I2 = 100.0%, p < 0.001), respectively. After performing a subgroup analysis, the prevalence of depression among women, healthcare workers, students, and adolescents was 0.31 (95% CI: 0.22, 0.41), 0.33 (95% CI: 0.26, 0.44), 0.32 (95% CI: 0.26, 0.39), and 0.37 (95% CI: 0.31, 0.44), respectively. Conclusion: The prevalence of depression and anxiety among the Chinese was overall high. Monitoring and surveillance of the mental health status of the population during crises such as sudden global pandemics are imperative. Systematic review registration: https://clinicaltrials.gov/, identifier [CRD42023402190].

A randomized double-blinded study assessing the dose-response of ropivacaine with dexmedetomidine for maintenance of labor with epidural analgesia in nulliparous parturients.

Background: The combination of ropivacaine and dexmedetomidine has been used as an epidural analgesic for inducing labor. However, there is limited data regarding the administration of epidural analgesia for labor maintenance, hence, this study aimed to determine the optimum concentration through dose-response curves of ropivacaine plus dexmedetomidine, which could be used along with the Programmed Intermittent Epidural Bolus (PIEB) technique. Methods: One hundred parturients were randomized into 4 groups who were administered four different doses of ropivacaine (dexmedetomidine at 0.4 µg mL-1): 0.04%, 0.06%, 0.08%, and 0.1%. The primary outcome that was determined included the proportion of patients experiencing breakthrough pain during their 1st stage of labor. Breakthrough pain was described as a visual analog scale [VAS] score of >30 mm, requiring supplemental epidural analgesia after the administration of at least one patient-controlled bolus. The effective concentration of analgesia that was used for labor maintenance in 50% (EC50) and 90% (EC90) of patients were calculated with the help of probit regression. Secondary outcomes included epidural block characteristics, side effects, neonatal outcomes, and patient satisfaction. Results: The results indicated that the proportion of patients without breakthrough pain was 45% (10/22), 55% (12/22), 67% (16/24), and 87% (20/23) for 0.04%, 0.06%, 0.08%, and 0.10% doses of the analgesic that were administered, respectively. The EC50 value was 0.051% (95% confidence interval [CI], 0.011%-0.065%) while the EC90 value was recorded to be 0.117% (95% CI, 0.094%-0.212%). Side effects were similar among groups. Conclusion: A ropivacaine dose of 0.117% can be used as epidural analgesia for maintaining the 1st stage of labor when it was combined with dexmedetomidine (0.4 µg mL-1) and the PIEB technique. Clinical Trial Register: https://www.chictr.org.cn/index.aspx, identifier ChiCTR2200059557.

Effect of palmitoylethanolamide on degeneration of a human-derived retinal pigment epithelial cell induced by all-trans retinal.

AIM: To study the effect of palmitoylethanolamide (PEA) on apoptosis of retinal pigment epithelial (RPE) cells induced by all-trans retinal (atRAL) and to explore the possible molecular mechanism. METHODS: CellTiter 96® Aqueous One Solution Cell Proliferation Assay (MTS) was used to detect the effect of PEA on human-derived retinal epithelial cells (ARPE-19) viability induced by atRAL. A Leica DMi8 inverted microscope was used to observe cell morphology. Reactive oxygen species (ROS) production was evaluated with 2',7'-dichlorodihydrof-luorescein diacetate (H2DCFDA) staining and fluorescence microscopy. Expression of c-Jun N-terminal kinase (JNK), phosphorylated JNK (p-JNK), c-Jun, phosphorylated c-Jun (p-c-Jun), Bak, cleaved caspase-3, C/EBP homologous protein (CHOP), and binding (Bip) protein levels were tested by Western blot. Abca4 -/- Rdh8 -/- mice, mouse models of atRAL clearance defects which displays some symbolic characteristics of dry age-related macular degeneration (AMD) and Stargardt disease (STGD1). In the animal models, PEA was injected intraperitoneally. The full-field electroretinogram was used to detect visual function under scotopic conditions traced from mice. Optical coherence tomography showed reconstitution or thickening of the retinal pigment epithelium layer. Effect of PEA on fundus injury induced by light in Abca4-/-Rdh8-/- mice was observed by fundus photography. RESULTS: PEA ameliorated ARPE-19 cells apoptosis and inhibited ROS (including mitochondrial ROS) production induced by atRAL. PEA improved the retinal functional, prohibited both RPE and photoreceptor from death, ameliorates light-induced fundus impairment in Abca4 -/- Rdh8 -/- mice. In vitro and in vivo, PEA inhibited JNK, p-JNK, c-Jun, p-c-Jun, Bak, cleaved caspase-3, CHOP, and Bip protein levels induced by all-trans retinal in ARPE-19 cells. CONCLUSION: PEA has effect on treating RPE cells apoptosis in retinopathy caused by atRAL accumulation. PEA is a potential treatment strategy for dry AMD and STGD1. The molecular mechanism is affecting the ROS-JNK-CHOP signaling pathway partly.

Analysis of the risk of death and clinical management for nasal or nasopharyngeal bleeding occurring after radiotherapy for nasopharyngeal carcinoma.

OBJECTIVE: To retrospectively analyze the risk factors for death in patients with nasal or nasopharyngeal bleeding after radiotherapy for nasopharyngeal carcinoma, and to explore clinical management strategies for the disease. METHODS: This was a retrospective case-control study. The clinical data from patients diagnosed with nasopharyngeal or nasopharyngeal hemorrhage after radiotherapy for nasopharyngeal carcinoma at the First Affiliated Hospital of Guangxi Medical University between January 2006 and October 2021 were retrospectively analyzed. Chi-square analysis and odds ratio (OR) calculation were performed to evaluate the death risk factors associated with the disease. And binary logistic regression analysis was used to detect some independent factors in this study. RESULTS: Of the 85 patients, 71 (83.5%) were male and 14 (14.5%) were female; 11 patients died (mortality rate: 12.9%), of which 9 died of asphyxia (7 with hemorrhagic shock), 1 died of multiorgan failure and acute respiratory distress syndrome, and 1 died of left cerebellar infarction. Nine potential mortality factors were evaluated; age, sex, nasal tamponade, and open mouth restriction were not significantly associated with death (P > 0.5); absence of immediate airway protection (in the major bleeding group) , absence of angiography, skull base destruction, major bleeding, and re-irradiation were significantly associated with death (P < 0.05). Among these factors, binary logistic regression model showed increased risk of death in patients without immediate airway protection (OR=18.14,95%CI:1.48-221.64), in patients without angiography (OR=14.65, 95%CI:2.37-90.73), and in those with re-irradiation (OR=13.23,95%CI:1.004-174.23). CONCLUSION: Binary logistic regression model shows that absence of immediate airway protection, absence of angiography, and re-irradiation are independent risk factors for death. The mortality rate due to bleeding after radiotherapy for nasopharyngeal carcinoma is high, and active management and intervention to address the risk factors for death is key to treat the disease and save patients' lives. At the same time, we need to consider the patient's causative state of bleeding.

Subcapsular renal haematoma after ureteroscopic lithotripsy: a single-centre, retrospective study in China.

OBJECTIVES: To investigate the incidence, predisposing factors, diagnosis and management of subcapsular renal haematoma (SRH) after ureteroscopic lithotripsy (URSL). DESIGN: Retrospective observational study. SETTING: Shandong Provincial Hospital, a 4500-bed tertiary hospital in China. PARTICIPANTS: The data from 1535 consecutive patients treated with URSL (including rigid URSL and flexible URSL) between January 2015 and October 2020 were retrospectively analysed. MAIN OUTCOME MEASURES: SRH after URSL confirmed via CT. The characteristics, operative data and outcomes of these patients were documented and compared. RESULTS: Six patients were confirmed to have an SRH after URSL on CT. The total incidence of SRH after URSL was 0.39%. The incidences of SRH after rigid URSL and flexible URSL were 0.38% and 0.41%, respectively. Unendurable ipsilateral flank pain and a significant decrease in haemoglobin after surgery were the typical clinical manifestations of SRH after URSL. There were no significant differences in age, sex, history of diabetes mellitus, preoperative hypertension, body mass index, stone laterality or perfusion pressure (p>0.05). However, SRH was significantly associated with the stone size, stone location, degree of hydronephrosis and operative duration (p<0.01). One patient was managed conservatively without further intervention, percutaneous drainage was performed in four patients and one patient underwent emergency angiography. No patients died of SRH. CONCLUSIONS: SRH is a rare but potentially serious complication of URSL. Severe hydronephrosis and a thin renal cortex preoperatively and prolonged operative duration are strong predisposing factors for SRH. Laparoscopic ureterolithotomy should be considered as an alternative surgery for patients with severe ureteral tortuosity. SRH is treated based on patients' clinical manifestations. Most patients can be managed with conservative treatment or percutaneous drainage alone.

Comparison of epidural dexmedetomidine to fentanyl in reducing ropivacaine dose in Programmed Intermittent Epidural Bolus plus Patient Controlled Epidural Analgesia during labor: A randomized, double-blind, controlled study.

Background: Dexmedetomidine has been documented to reduce the dose of both intrathecal local anesthetic during cesarean delivery, and the concentration of ropivacaine needed for inducing analgesia during labor. However, few studies have compared adjuvant dexmedetomidine to fentanyl on how they impact the dose of ropivacaine required during labor. The aim of the current study was to evaluate the efficacy of epidural dexmedetomidine at doses of 0.3, 0.4, or 0.5 and 2 µg/ml of fentanyl (the traditional clinical concentration), when added to epidural 0.125% ropivacaine. Methods: This was a randomized, double-blinded study that comprised one hundred eighty-eight patients, allocated into four groups receiving either epidural fentanyl at 2 µg/ml, or dexmedetomidine at 0.3, 0.4, or 0.5 µg/ml for labor analgesia. The primary outcome was the amount of ropivacaine necessary per hour. Secondary outcomes included visual analogue pain scale (VAS), motor block (Bromage Scale), side effects, patient satisfaction, and neonatal outcomes. Results: At the completion of the study, data from 165 participants were analyzed. The mean hourly amount of epidural ropivacaine administered was 16.2 ± 3.3, 14.0 ± 3.1, 13.1 ± 3.7 and 12.1 ± 2.5 ml/h in the 2 µg/ml fentanyl group, and the 0.3, 0.4 and 0.5 µg/ml dexmedetomidine groups, respectively. There was a significant difference among groups in the mean hourly consumption of epidural ropivacaine (P < 0.0001 for 1 way ANOVA). The frequency of PCEA (patient-controlled epidural analgesia) was significantly higher in the fentanyl group than in the three dexmedetomidine groups (P < 0.001), and similar among the dexmedetomidine groups. The mean values of the VAS among all groups were similar over time, P > 0.05. The incidence of pruritus in the fentanyl group was 17.5%, whereas no patient experienced pruritus in any of the dexmedetomidine groups, P < 0.0001. Conclusion: The study demonstrated that epidural dexmedetomidine (0.3 and 0.4 µg/ml) was superior to standard dose epidural fentanyl in reducing the mean hourly amount of ropivacaine administered, and minimizing opioid-related side effects. Further large and multicenter studies would be necessary to confirm the benefits of dexmedetomidine, and potentially serve as an alternative to opioids for routine use in labor analgesia. Clinical trial registration: [http://www.chictr.org.cn/showproj.aspx?proj=62846], identifier [ChiCTR2000039067].

Individual chronic mountain sickness symptom is an early warning sign of cognitive impairment.

OBJECTIVE: To investigate the relationship between various chronic mountain sickness (CMS) symptoms and cognitive performances and identify whether individual CMS symptom can be used as early warning signs of specific cognitive impairment in long-term high altitude migrators. METHODS: A total of 287 workers living at an altitude of 3850 m for 1-5 years participated in the study. According to the International Qinghai CMS Diagnostic Criteria, a questionnaire survey was conducted to measure the existence and severity of 7 self-perceptible CMS symptoms in addition to hemoglobin (Hb) levels in the blood. Six neurobehavioral tests were then conducted to assess cognitive function, and physiological indices, including Pittsburgh Sleep Quality Index (PSQI) and arterial oxygen saturation were also measured. RESULTS: Compared with a score of 0 for each CMS symptom, scores of 1-3 universally corresponded to impairment in some aspects of cognition. Moreover, the correlation analysis revealed that subjects with different CMS symptoms exhibited specific aspects of cognitive impairment. Cyanosis was associated with slower auditory and visual reactions, reduced motion agility and poor visual memory ability (R = =0.236, 0.261, 0.155, 0.221, P < 0.01). Sleep disturbance and excessive erythrocytosis were significantly correlated to poor memory ability (R = =0.206~0.251, P < 0.01), and the symptoms of headache were mainly associated with impaired motion agility (R = =0.266, P < 0.01). The results also indicated that Hb ≥ 200 g/L, SpO2 ≤ 88%, and PSQI scores ≥ 7, which correspond to excessive erythrocytosis, cyanosis and sleep disturbance symptoms respectively, predicted the decline of cognitive function. CONCLUSIONS: The characteristics of symptoms used in Qinghai CMS Score System were associated with specific cognitive impairments in long-term plateau migrators, which supported the usefulness of monitoring cognitive status using CMS-related symptoms for both CMS patients and non-CMS people at high altitude.

Stability and bifurcation of a delayed diffusive predator-prey system with food-limited and nonlinear harvesting.

Based on ecological significance, a delayed diffusive predator-prey system with food-limited and nonlinear harvesting subject to the Neumann boundary conditions is investigated in this paper. Firstly, the sufficient conditions of the stability of nonnegative constant steady state solutions of system are derived. The existence of Hopf bifurcation is obtained by analyzing the associated characteristic equation and the conditions of Turing instability are derived when the system has no delay. Furthermore, the occurrence conditions the Hopf bifurcation are discussed by regarding delay expressing the gestation time of the predator as the bifurcation parameter. Secondly, by using upper-lower solution method, the global asymptotical stability of a unique positive constant steady state solution of system is investigated. Moreover, we also give the detailed formulas to determine the direction, stability of Hopf bifurcation by applying the normal form theory and center manifold reduction. Finally, numerical simulations are carried out to demonstrate our theoretical results.

Platelets are novel regulators of neovascularization and luteinization during human corpus luteum formation.

The human corpus luteum is a unique endocrine organ that is periodically constructed from the ovulated follicle. During human corpus luteum formation, which is well known as a pathophysiological model for tissue remodeling, the precise mechanisms by which centripetal vascular development is regulated remain unknown. Recently platelets were reported to contain chemoattractive substances with the potential to induce endothelial migration. In this study, we examined the involvement of platelets in the early tissue remodeling process of the human corpus luteum. An immunohistochemical study demonstrated that considerable amounts of red blood cells and CD41-positive platelets were localized at extravascular sites among luteinizing granulosa cells after ovulation. Platelet deposition gradually decreased and became limited near the central cavity toward which microvessels were extending. Platelets were hardly observed in the midluteal phase when the vascular network had already been established. These platelets expressed CD62P/P-selectin and were colocalized with extracellular matrix, suggesting that platelets had been activated by the extracellular matrix. Progesterone production by luteinizing granulosa cells that were isolated from patients undergoing in vitro fertilization therapy was significantly promoted by direct contact with platelets during 4-d culture. Platelet-derived soluble factors induced spreading in granulosa cell morphology. These factors also increased the migration of human umbilical vein endothelial cells, whereas luteinizing granulosa cells attenuated platelet-induced endothelial cell migration. These findings lead us to propose the novel concept that platelets are regulators of endothelial cell migration and granulosa cell luteinization in the remodeling process of the human corpus luteum.

Integrin alpha5 is involved in fibronectin-induced human extravillous trophoblast invasion.

To identify the molecules involved in human extravillous trophoblast (EVT) invasion, we raised murine mAbs that react with EVTs and obtained one mAb (CHL3) that inhibited invasion of a human choriocarcinoma-derived cell line, BeWo cells. The N-terminal 22 aminoacid sequence of the CHL3 antigen (150kDa) purified from placental tissue completely matched that of integrin alpha5, which is known to interact with fibronectin. Double immunohistochemical staining and flow cytometry confirmed the reactivity of CHL3 with integrin alpha5 and its expression on the surface of BeWo cells and human EVTs isolated from villous explant cultures. CHL3 mAb inhibited the attachment of human EVTs and BeWo cells to fibronectin-coated dishes, but not to Matrigel dishes. In the Matrigel invasion assay supplemented with or without fibronectin, the invasion of isolated EVTs and BeWo cells was attenuated by treatment with CHL3 without affecting cell proliferation. During invasion assays, the production of matrix metalloproteases 2 and 9 was not changed by CHL3. These findings suggest that interaction with fibronectin through integrin alpha5 plays an important role in human extravillous trophoblast invasion.

[Effect of total flaveos of Gymostemma pentaphyllum on protein expression of Fas/FasL genes and TNF-alpha concentration in cultured neonatal rat cardiomyocytes with hypoxia-reoxygenation].

OBJECTIVE: To study the effect of total flaveos of Gymostemma pentaphyllum on the protein expression of apoptosis-associated Fas/FasL gene and tumor necrosis factor-alpha (TNF-alpha) concentration in cultured neonatal rat cardiomyocytes with hypoxia-reoxygenation (H/R). METHOD: A cultured primary neonatal rat cardiomyocytes model with H/R was erected, experiments were divided into six groups, (1)control group, (2)H/R group, (3)15 mg x L(-1) TFG plus H/R group, (4)45 mg x L(-1) TFG plus H/R group, (5) 105 mg x L(-1) TFG plus H/R group, (6)105 mg x L(-1) TFG group. TNF-aconcentration in cultured cardiomyocytes with H/R, was determined by ELISA method, the protein expression of Fas/FasL genes were estimated by immunohisto-chemistry. RESULT: After cardiomyocytes were made with H/R, Compared with control group, the positive expression index (PEI) of Fas/FasL proteins in cardiomyocytes increased significantly, Compared with H/R groups, the PEI of Fas/FasL proteins were lower significantly in groups with different dosages of TFG (P < 0.05). TFG inhibited the secretion of TNF-alpha from myocardial cells and increased the survival rate of myocardial cells. CONCLUSION: The protein expression of apoptosis-associated Fas/FasL genes increased during H/R. The TFG can protect myocardium against H/R injury by decreasing the production of TNF-alpha, downregulating the protein expression of Fas/FasL genes, and then inhibiting myocyte apoptosis.

Regulation of human extravillous trophoblast function by membrane-bound peptidases.

During human placentation, the invasion of extravillous trophoblasts (EVTs) into maternal decidual tissues, especially toward maternal spiral arteries, is considered an essential process for subsequent normal fetal development. However, the precise regulatory mechanisms to induce EVT invasion toward arteries and/or to protect EVTs from further invasion have not been well understood. Recently, we found that two cell surface peptidases, dipeptidyl peptidase IV (DPPIV) and carboxypeptidase-M (CP-M,) are differentially expressed on EVTs. DPPIV expression was mainly observed on EVTs that had already ceased invasion. CP-M was detected on migrating EVTs including endovascular trophoblasts in the maternal arteries. The enzymatic inhibition of these peptidases affected the invasive property of choriocarcinoma-derived cell lines, BeWo and JEG3 cells. In addition, a chemokine, RANTES, that is one of the substrates for DPPIV, enhanced invasion of EVTs isolated from primary villous explant culture and its receptor, CCR1, was specifically expressed on migrating EVTs toward maternal arteries. Furthermore, a novel membrane-bound cell surface peptidase, named laeverin, was found to be specifically expressed on EVTs that had almost ceased invasion. These findings suggest that membrane-bound peptidases are important factors regulating EVT invasion during early placentation in humans.

New regulatory mechanisms for human extravillous trophoblast invasion.

Human extravillous trophoblasts (EVT) invade maternal deciduas and reconstructed maternal spiral arteries during early placentation. However, the precise regulatory mechanisms to induce EVT invasion toward arteries and/or to protect EVT from further invasion have not been well understood. Recently, it was found that EVT that had already ceased their invasion, specifically expressed cluster of differentiation (CD9) and dipeptidyl peptidase IV (DPPIV) on their cell surface. In addition, EVT migrating to maternal spiral arteries expressed CC chemokine receptor type-1 (CCR-1), which is a chemokine receptor for regulated on activation normal T cell expressed and secreted (RANTES) and so on. CD9 is associated with integrin molecules on the cell surface and is considered to modulate integrin function. In contrast, DPPIV is a cell surface peptidase that can metabolize RANTES at extracellular sites before its accessing to the chemokine receptors. In vitro functional assay showed that CD9, DPPIV and RANTES are involved in the regulation for EVT invasion. From these findings, it can be proposed that CD9 and DPPIV, including chemokines, are new regulatory factors for human extravillous trophoblasts. (Reprod Med Biol 2005; 4: 189-195).

Greenhouse gas emissions from a wheat-maize double cropping system with different nitrogen fertilization regimes.

Here, we report on a two-years field experiment aimed at the quantification of the emissions of nitrous oxide (N2O) and methane (CH4) from the dominant wheat-maize double cropping system in North China Plain. The experiment had 6 different fertilization strategies, including a control treatment, recommended fertilization, with and without straw and manure applications, and nitrification inhibitor and slow release urea. Application of N fertilizer slightly decreased CH4 uptake by soil. Direct N2O emissions derived from recommended urea application was 0.39% of the annual urea-N input. Both straw and manure had relatively low N2O emissions factors. Slow release urea had a relatively high emission factor. Addition of nitrification inhibitor reduced N2O emission by 55%. We conclude that use of nitrification inhibitors is a promising strategy for N2O mitigation for the intensive wheat-maize double cropping systems.

Platelet-derived soluble factors induce human extravillous trophoblast migration and differentiation: platelets are a possible regulator of trophoblast infiltration into maternal spiral arteries.

In early pregnancy, human extravillous trophoblasts (EVTs) invade and remodel maternal arteries. We have previously demonstrated that CCR1 is expressed on perivascular/endovascular trophoblasts and that CCR1 ligands promote EVT migration. In this study, we examined the physiologic roles of platelet-derived chemoattractants on EVT invasion. By immunohistochemistry, maternal platelets were localized among endovascular trophoblasts within the lumen of spiral arteries. Extracellular matrices (ECMs) were also detected among endovascular trophoblasts and platelets, suggesting that the platelets in these arteries were activated by ECMs. In vitro, platelets attached to EVTs isolated from human villous explant cultures and expressed P-selectin on the cell surface. Platelets significantly enhanced migration of EVTs without affecting proliferation of EVTs or secretion of MMP-2 or MMP-9. The invasion-enhancing effect of platelet-derived culture medium on EVTs was neutralized by anti-CCR1 antibody. Heat treatment completely abrogated the invasion-promoting effects of platelet-derived culture medium, but charcoal stripping did not. Platelets also induced endovascular trophoblast-like morphologic changes and integrin alpha1 expression in EVTs during 48-hour culture. These findings suggest that maternal platelets activated in the spiral arteries can regulate trophoblastic vascular infiltration and differentiation by releasing various soluble factors.