Precise Synthesis of Organic Cocrystal Alloys with Full-Spectrum Emission Characteristics for the Stepless Color Changing Display

Organic luminescent materials are indispensable in optoelectronic displays and solid-state luminescence applications. Compared with single-component, multi-component crystalline materials can improve optoelectronic characteristics. This work forms a series of full-spectrum tunable luminescent charge-transfer (CT) cocrystals ranging from 400 to 800 nm through intermolecular collaborative self-assembly. What is even more interesting is that o-TCP-Cor(x)-Pe(1-x), p-TCP-Cor(x)-Pe(1-x), and o-TCP-AN(x)-TP(1-x) alloys are prepared based on cocrystals by doping strategies, which correspondingly achieve the stepless color change from blue (CIE [0.22, 0.44]) to green (CIE [0.16, 0.14]), from green (CIE [0.27, 0.56]) to orange (CIE [0.58, 0.42]), from yellow (CIE [0.40, 0.57]) to red (CIE [0.65, 0.35]). The work provides an efficient method for precisely synthesizing new luminescent organic semiconductor materials and lays a solid foundation for developing advanced organic solid-state displays.

Visualizing the interfacial-layer-based epitaxial growth process toward organic core-shell architectures

Organic heterostructures (OHTs) with the desired geometry organization on micro/nanoscale have undergone rapid progress in nanoscience and nanotechnology. However, it is a significant challenge to elucidate the epitaxial-growth process for various OHTs composed of organic units with a lattice mismatching ratio of > 3%, which is unimaginable for inorganic heterostructures. Herein, we have demonstrated a vivid visualization of the morphology evolution of epitaxial-growth based on a doped interfacial-layer, which facilitates the comprehensive understanding of the hierarchical self-assembly of core-shell OHT with precise spatial configuration. Significantly, the barcoded OHT with periodic shells obviously illustrate the shell epitaxial-growth from tips to center parts along the seeded rods for forming the core-shell OHT. Furthermore, the diameter, length, and number of periodic shells were modulated by finely tuning the stoichiometric ratio, crystalline time, and temperature, respectively. This epitaxial-growth process could be generalized to organic systems with facile chemical/structural compatibility for forming the desired OHTs.

[Effects of ppk1 deletion on the drug susceptibility of uropathogenic Escherichia coli producing ESBLs]

To investigate the effect and the mechanism of ppk1 gene deletion on the drug susceptibility of uropathogenic Escherichia coli producing extended-spectrum beta-lactamases (ESBLs-UPEC). The study was an experimental study. From March to April 2021, a strain of ESBLs-UPEC (genotype was TEM combined with CTX-M-14) named as UE210113, was isolated from urine sample of the patient with urinary tract infection in the Laboratory Department of Guangzhou Eighth People's Hospital, meanwhile its ppk1 gene knock-out strain Δpk1 and complemented strain Δpk1-C were constructed by suicide plasmid homologous recombination technique, which was used to study the effect of ppk1 gene on ESBLs-UPEC drug sensitivity and its mechanism. The drug susceptibility of UE210113, Δpk1, and Δpk1-C were measured by Vitek2 Compact System and broth microdilution method. The quantitative expression of ESBLs, outer membrane protein and multidrug efflux systems encoding genes of UE210113, Δpk1 and Δpk1-C were performed by using qRT-PCR analysis. By using two independent sample Mann-Whitney U test, the drug susceptibility results showed that, compared with UE210113 strain, the sensitivities of Δpk1 to ceftazidime, cefepime, tobramycin, minocycline and cotrimoxazole were enhanced (Z=-2.121,P<0.05;Z=-2.236,P<0.05;Z=-2.236,P<0.05;Z=-2.121,P<0.05), and the drug susceptibility of Δpk1-C restored to the same as which of UE210113 (Z=0,P>0.05). The expression levels of ESBLs-enconding genes blaTEM and blaCTX-M-14 in Δpk1 were significantly down-regulated compared with UE210113, but the expression was not restored in Δpk1-C. The expression of outer membrane protein gene omp F in Δpk1 was significantly up-regulated, while the expression of omp A and omp C were down-regulated. The results showed that the expression of multidrug efflux systems encoding genes tol C, mdt A and mdtG were down-regulated in Δpk1 compared with UE210113. The expression of all of the outer membrane protein genes and the multidrug efflux systems genes were restored in Δpk1-C. In conclusion,the lost of ppk1 gene can affect the expression of the outer membrane protein and multidrug efflux systems encoding genes of ESBLs-UPEC, which increase the sensitivity of ESBLs-UPEC to various drugs.

[Artificial intelligence technology enables ultrasonography in precision diagnosisand treatment of liver diseases]

Liver disease is one of the major problems affecting human health. Ultrasound plays an important role in diagnosis and treatment of diffuse and focal liver diseases. However, conventional ultrasound evaluation is subjective and provides limited information. Artificial intelligence (AI) technology may supplement the disadvantages of conventional ultrasound and has been widely used in the field of ultrasound in liver diseases. To date, remarkable progress has been achieved for the use of AI technology in the diagnosis, assessment of therapeutic efficacy and prognosis prediction of liver diseases. This paper reviews the research progress of ultrasound image-based AI technology in the diagnosis and treatment of diffuse and focal liver diseases.

[Survey of Oncomelania hupensis in national schistosomiasis surveillance sites of Guangxi Zhuang Autonomous Region from 2015 to 2019]

OBJECTIVE

To investigate the distribution characteristics of Oncomelania hupensis in Guangxi Zhuang Autonomous Region, so as to provide insights into the assessment of the risk of schistosomiasis transmission and the scientific formulation of the schistosomiasis surveillance strategy.

METHODS

From 2015 to 2019, a total of 19 national schistosomiasis surveillance sites were assigned in Guangxi Zhuang Autonomous Region, including 4 fixed sites and 15 mobile sites. Snail survey was performed by means of systematic sampling in combination with environmental sampling, and the infection of Schistosoma japonicum was detected by the crushing method combined with loop-mediated isothermal amplification (LAMP) assay.

RESULTS

From 2015 to 2019, snail habitats were detected at areas of 17 040 to 39 527 m², including 6 214 m² emerging snail habitats and 16 563 m² re-emerging snail habitats. The overall mean density of living snails was 0.019 2 snails/0.1 m² and the occurrence of frames with snails was 1.11% in the national schistosomiasis surveillance sites; however, no S. japonicum infection was identified in snails. The area of snail habitats increased by 121.46% in the national surveillance sites in 2019 as compared to that in 2015; however, 50.34% (Z = -0.422, P > 0.05) and 42.85% (χ² = 130.41, P < 0.01) reductions were seen in the overall means density of living snails and the occurrence of frames with snails. All snail habitats were distributed in the 4 fixed surveillance sites, and were mainly found in ditches, paddy fields and dry lands, with weeds as the primary vegetation type.

CONCLUSIONS

There are still risk factors leading to re-emergent transmission of schistosomiasis in Guangxi Zhuang Autonomous Region, such as local snail spread, and the monitoring of schistosomiasis remains to be reinforced to further consolidate the achievements of schistosomiasis elimination in the region.

Efficient All-Inorganic Perovskite Light-Emitting Diodes with Cesium Tungsten Bronze as a Hole-Transporting Layer

The realization of high-performance optoelectronic devices requires excellent charge-transporting layers and efficient carrier recombination. Herein, we synthesized cesium tungsten bronze (Cs_0.32WO₃) nanocrystals and utilized them as the hole-transporting material to fabricate all-inorganic perovskite light-emitting diodes (PeLEDs). Due to the excellent carrier balance characteristics via comparison between the hole-only device and electron-only device, the all-inorganic PeLEDs with CsPbBr₃ as the light-emitting layer present the maximum current efficiency of 31.51 cd/A and external quantum efficiency (EQE) of 8.48%, which are self-evidently enhanced compared with the PEDOT:PSS (14.78 cd/A, 4.03%) and WO₃ (24.75 cd/A, 6.18%) based devices. Considering the remarkably improved device performance, the proposed HTL of Cs_0.32WO₃ is promising, acting as a favorable building block for high-efficiency light-emitting devices.

[Analysis of the pathogenic characteristics of fungal bloodstream infection in severe burn patients]

Objective: To retrospectively analyze the diagnosis time, pathogen distribution, and drug resistance of fungal bloodstream infection in severe burn patients. Methods: Blood samples were collected from 55 severe burn patients with fungal bloodstream infection (including 46 males and 9 females, aged 42 (1, 78) years) admitted to the intensive care unit of the Institute of Burn Research of the First Affiliated Hospital of Army Medical University (the Third Military Medical University) from July 2011 to May 2019 for retrospective analysis. Microbial monitoring system was used to cultivate pathogens, API yeast identification kit and Candida chromogenic medium were used to identify pathogens, and Kirby-Bauer paper disk diffusion method was used to detect drug resistance of fungi to fluconazole, amphotericin B, itraconazole, ketoconazole, and voriconazole. The positive rate of blood fungal culture, mortality rate, distribution of local fungal proliferation sites, the diagnosis time distribution of fungal bloodstream infection, the distribution of fungal species, resistance to commonly-used antifungal drugs, and the use of antibiotics were assessed. The WHONET 5.6 software was applied to analyze the distribution and drug resistance of fungi. Results: (1) Totally 4 839 blood samples were collected during the 9 years, and 122 strains of fungi were isolated, with positive rate of 2.52%. The mortality rate was 14.55% (8 patients) in 55 patients. Catheter fungal proliferation ranked the first among 30 cases of local fungal proliferation. (2) The diagnosis time of fungal bloodstream infection mainly distributed in ≤1 week of hospitalization [32.73% (18/55)]. (3) Among the 55 strains of fungi detected, the detection rate of Candida parapsilosis ranked the first (21.82%, 12 strains), Candida glabrata was the second (18.18%, 10 strains), and Candida tropicalis was tied with Candida albicans in the third place (14.55%, 8 strains). All the detected fungi were sensitive to amphotericin B, and the resistance rates to voriconazole, fluconazole, itraconazole, and ketoconazole were between 4.5% and 9.1%. (4) Droad-spectrum antibiotics were used in all the 55 patients, ≥3 kinds of antibiotics were used in 44 patients, and 37 patients used antibacterial drugs ≥7 days. Conclusions: The diagnosis time of fungal bloodstream infection in the 55 severe burn patients was mainly within 1 week of hospitalization. Candida parapsilosis is the most commonly detected fungal species. Catheter fungal proliferation occurs most commonly among the 30 patients with local fungal proliferation. All the detected fungi were sensitive to amphotericin B, with low drug resistance to voriconazole, fluconazole, itraconazole, and ketoconazole. Broad-spectrum antibiotics were overused in the severe burn patients with fungal bloodstream infection.

[Analysis of distribution and drug resistance of pathogens isolated from 159 patients with catheter-related bloodstream infection in burn intensive care unit]

Objective: To analyze the distribution and drug resistance of pathogens isolated from patients with catheter-related bloodstream infection (CRBSI) in burn intensive care unit (BICU). Methods: From January 2011 to December 2018, among 2 264 patients who were peripherally inserted central venous catheter at the BICU of the First Affiliated Hospital of Army Medical University (the third Military Medical University), hereinafter referred to as the author's unit, 159 patients were diagnosed CRBSI, including 131 males and 28 females, aged 43 (1, 79) years. The pathogens primarily isolated from peripheral venous blood and central venous catheter blood/anterior central venous catheter specimen of patients with CRBSI were retrospectively analyzed. API bacteria identification kits and automatic microorganism identification instrument were used to identify pathogens. Broth micro-dilution method or Kirby-Bauer paper disk diffusion method was used to detect the drug resistance of the pathogens to 5 antifungal drugs including fluconazole and itraconazole, etc., and 37 antibacterial drugs including tigecycline and imipenem, etc. Modified Hodge test was used to further identify imipenem- and meropenem-resistant Klebsiella pneumonia. D test was used to detect erythromycin-induced clindamycin resistant Staphylococcus aureus. The WHONET 5.6 software was applied to analyze the annual incidence of CRBSI, mortality of patients with CRBSI, incidence of CRBSI cases, distribution of infection site, and duration of catheterization, detection of Gram-negative and Gram-positive bacteria, fungi, methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-sensitive Staphylococcus aureus (MSSA), and drug resistance of fungi and major Gram-negative and Gram-positive bacteria to the commonly used antibiotics in clinic. Results: (1) The incidence of CRBSI was 7.0% (159/2 264) during the eight years, which was slightly higher in 2014 and 2017 with 13.6% (30/221) and 11.1% (24/217) respectively. The mortality rate of patients with CRBSI was 7.5% (12/159). (2) The incidence of CRBSI cases was 14.9% (338/2 264); the main infection site was femoral vein, totally 271 cases (80.2%), and the duration of catheterization of this site was 9 (2, 25) d. (3) During the eight years, totally 543 strains of pathogens were isolated, including 353 (65.0%) strains of Gram-negative bacteria, 140 (25.8%) strains of Gram-positive bacteria, and 50 (9.2%) strains of fungi. The top three isolated pathogens with isolation rate from high to low were Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, accounting for 23.2% (126/543), 17.1% (93/543), and 15.7% (85/543), respectively. Fungi were mainly Candida parapsilosis. Among the Staphylococcus aureus, the detection rate of MRSA was 98.9% (92/93), and that of MSSA was 1.1% (1/93). (4) Except for the low drug resistance rates to polymyxin B, minocycline, and tigecycline, the drug resistance rates of Acinetobacter baumannii to the other antibiotics were considerably high (80.1%-100.0%). Pseudomonas aeruginosa was not resistant to polymyxin B but highly resistant to netilmicin (88.7%) and piperacillin (92.6%), with resistance rates to the other antibiotics from 34.5% to 62.7%. Klebsiella pneumoniae was not resistant to tigecycline and lowly resistant to imipenem and meropenem (28.9%, 9 imipenem- and meropenem-resistant strains were further confirmed by modified Hodge test), with resistance rates to the other antibiotics from 40.9% to 95.2%. The resistance rates of MRSA to most antibiotics were higher than those of MSSA. MRSA was not resistant to linezolid, vancomycin, teicoplanin, sulfamethoxazole, or tigecycline. The resistance rates of MRSA to clindamycin and erythromycin were 7.9% and 62.0%, respectively, and those to the other antibiotics were higher than 91.5%. Except for the complete resistance to penicillin G and tetracycline, MSSA was not resistant to the other antibiotics. Thirty-three strains of Staphylococcus aureus showed resistance to erythromycin-induced clindamycin. Fungi was not resistant to amphotericin B, with drug resistance rates to voriconazole, itraconazole, ketoconazole, and fluconazole from 4.2% to 6.2%. Conclusions: The incidence of CRBSI and mortality of patients with CRBSI are high in BICU of the author's unit, and the main infection site is femoral vein. There are various types of pathogens in patients with CRBSI, and most of them are Gram-negative. The top three isolated pathogens are Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, accompanying with grim drug resistance phenomenon.

[Effects of vitamin D3 on intestinal mucosal barrier of mice with severe burns]

Objective: To explore the effects of vitamin D₃ on intestinal mucosal barrier of mice with severe burns. Methods: Forty-two C57BL/6C male mice aged eight to twelve weeks were divided into vitamin D₃ vehicle+ sham injury group of seven mice, vitamin D₃ vehicle+ burn injury group of fourteen mice, vitamin D₃+ sham injury group of seven mice, and vitamin D₃+ burn injury group of fourteen mice according to random number table. Mice in vitamin D₃ vehicle+ sham injury group and vitamin D₃ vehicle+ burn injury group were injected with vehicle of vitamin D₃ at a dose of 0.1 mL intraperitoneally at 1, 24, and 48 h before burn experiment. Mice in vitamin D₃+ sham injury group and vitamin D₃+ burn injury group were injected with vitamin D₃ at a dose of 100 ng/kg dissolved in 0.1 mL vehicle intraperitoneally at the same time points. Mice in vitamin D₃ vehicle+ burn injury group and vitamin D₃+ burn injury group were inflicted with 30% total body surface area full-thickness dermal scald (hereinafter referred to as burn) on the back by 98 ℃ hot water for 3 to 4 seconds. And mice in vitamin D₃ vehicle+ sham injury group and vitamin D₃+ sham injury were treated with 37 ℃ water on the back for 3 to 4 seconds to simulate injury. Seven mice in vitamin D₃ vehicle+ sham injury group and seven mice in vitamin D₃+ sham injury group at post injury hour (PIH) 24, and seven mice in vitamin D₃ vehicle+ burn injury group and seven mice in vitamin D₃+ burn injury group at PIH 6 and 24 were sacrificed respectively to collect mesentery lymph nodes, spleens, livers, and intestinal tissue. The mesentery lymph nodes, spleens, and livers of mice in each group were collected to observe growth of bacteria, and number of bacteria was counted. Intestinal tissue of mice in each group was collected to detect protein expressions of zonal occludin 1 (ZO-1) and occludin by immunohistochemistry staining method, distribution of ZO-1 by immunofluorescence staining method, and expression of occludin by Western blotting. Data were processed with Kruskal-Wallis H test, Nemenyi test, one-way analysis of variance, t test, and Bonferroni correction. Results: (1) At PIH 6 and 24, bacterial counts of mesentery lymph nodes, livers, and spleens of mice in vitamin D₃ vehicle+ burn injury group were significantly higher than those of mice in vitamin D₃ vehicle+ sham injury group (P<0.05). At PIH 6, bacterial counts of livers and spleens of mice in vitamin D₃+ burn injury group were significantly lower than those of mice in vitamin D₃ vehicle+ burn injury group (P<0.05). At PIH 24, bacterial counts of mesentery lymph nodes and livers of mice in vitamin D₃+ burn injury group were significantly lower than those of mice in vitamin D₃ vehicle+ burn injury group (P<0.05). (2) At PIH 6 and 24, expressions of ZO-1 and occludin of intestinal tissue of mice in vitamin D₃ vehicle+ burn injury group were significantly lower than those of mice in vitamin D₃ vehicle+ sham injury group, and expressions of ZO-1 and occludin of intestinal tissue of mice in vitamin D₃+ burn injury group were close to those of mice in vitamin D₃+ sham injury group. At PIH 6 and 24, expressions of ZO-1 and occludin of intestinal tissue of mice in vitamin D₃+ burn injury group were significantly higher than those of mice in vitamin D₃ vehicle+ burn injury group. (3) At PIH 6 and 24, compared with that of mice in vitamin D₃ vehicle+ sham injury group, distribution of ZO-1 of intestinal mucosal epithelium of mice in vitamin D₃ vehicle+ burn injury group was discontinuous. Distribution of ZO-1 of intestinal mucosal epithelium of mice in vitamin D₃+ sham injury group was normal, and the distribution of ZO-1 of intestinal mucosal epithelium of mice in vitamin D₃+ burn injury group was with good continuity. (4) At PIH 6 and 24, expressions of occludin of intestinal tissue of mice in vitamin D₃ vehicle+ burn injury group were 0.720±0.003, 0.638±0.052 respectively, significantly lower than 0.918±0.003 of mice in vitamin D₃ vehicle+ sham injury group (t=57.33, 5.36, P<0.05). At PIH 6 and 24, expressions of occludin of intestinal tissue of mice in vitamin D₃+ burn injury group were 0.994±0.058, 1.064±0.060, close to 0.938±0.023 of mice in vitamin D₃+ sham injury group (t=0.91, 1.96, P>0.05). At PIH 6 and 24, expressions of occludin of intestinal tissue of mice in vitamin D₃ vehicle+ burn injury group were significantly lower than those of mice in vitamin D₃+ burn injury group (t=4.75, 5.35, P<0.05). Conclusions: Intestinal bacterial translocation can occur in the early stage of severe burn. And vitamin D₃ plays a protective role in the intestinal mucosal barrier post severe burn to reduce the bacterial translocation by protecting tight junction proteins of intestinal epithelium.

Controlled synthesis of organic single-crystalline nanowires via the synergy approach of the bottom-up/top-down processes

The controlled fabrication of organic single-crystalline nanowires (OSCNWs) with a uniform diameter in the nanoscale via the bottom-up approach, which is just based on weak intermolecular interaction, is a great challenge. Herein, we utilize the synergy approach of the bottom-up and the top-down processes to fabricate OSCNWs with diameters of 120 ± 10 nm through stepwise evolution processes. Specifically, the evolution processes vary from the self-assembled organic micro-rods with a quadrangular pyramid-like end-structure bounded with {111}s and {11-1}s crystal planes to the "top-down" synthesized organic micro-rods with the flat cross-sectional {002}s plane, to the organic micro-tubes with a wall thickness of ∼115 nm, and finally to the organic nanowires. Notably, the anisotropic etching process caused by the protic solvent molecules (such as ethanol) is crucial for the evolution of the morphology throughout the whole top-down process. Therefore, our demonstration opens a new avenue for the controlled-fabrication of organic nanowires, and also contributes to the development of nanowire-based organic optoelectronics such as organic nanowire lasers.

High performance blue quantum dot light-emitting diodes employing polyethylenimine ethoxylated as the interfacial modifier

Efficient electron-injection into the emitting layer (EML) plays a pivotal role in the fabrication of high performance blue quantum dot light-emitting diodes (QLEDs). Herein, we reduce the electron-transporting barrier at the ITO/ETL (electron-transporting layer) interface from 0.7 eV to 0.4 eV by spin-coating a polyethylenimine ethoxylated (PEIE) film (8 nm) on the ITO substrate. Meanwhile, the electron-injection barrier was reduced from 0.5 to 0.1 eV at the ETL/QD interface by employing the incorporation of PEIE (0.1 wt%) into a ZnO layer. These above two interfacial modifications jointly decrease the electron barrier and make the electron transportation easier. As a result, the optimized QLEDs with the 460 nm emission peak exhibit a maximum external quantum efficiency (EQE) of 7.85%, which is enhanced by 1.4 fold compared with the reference device (5.68%). It is demonstrated that the facile interfacial modification by the organic polymer PEIE contributes to the fabrication of high-efficiency blue QLEDs.

Polymer as an Additive in the Emitting Layer for High-Performance Quantum Dot Light-Emitting Diodes

A facile but effective method is proposed to improve the performance of quantum dot light-emitting diodes (QLEDs) by incorporating a polymer, poly(9-vinlycarbazole) (PVK), as an additive into the CdSe/CdS/ZnS quantum dot (QD) emitting layer (EML). It is found that the charge balance of the device with the PVK-added EML was greatly improved. In addition, the film morphology of the hole-transporting layer (HTL) which is adjacent to the EML, is substantially improved. The surface roughness of the HTL is reduced from 5.87 to 1.38 nm, which promises a good contact between the HTL and the EML, resulting in low leakage current. With the improved charge balance and morphology, a maximum external quantum efficiency (EQE) of 16.8% corresponding to the current efficiency of 19.0 cd/A is achievable in the red QLEDs. The EQE is 1.6 times as high as that (10.5%) of the reference QLED, comprising a pure QD EML. This work demonstrates that incorporating some polymer molecules into the QD EML as additives could be a facile route toward high-performance QLEDs.

Pathophysiology of chronic pancreatitis induced by dibutyltin dichloride joint ethanol in mice

AIM: To search for a new chronic pancreatitis model in mice suitable for investigating the pathophysiological processes leading to pancreatic fibrosis.

METHODS: The mice were randomly divided into 2 groups (n = 50), control group and model group. The mice in model group were given ethanol (10%) in drinking water after injection of dibutyltin dichloride (DBTC) (8 mg/kg BW) in tail vein. The mice in control group were injected with only solvent into tail vein (60% ethanol, 20% glycerine and 20% normal saline) and drank common water. At days 1, 7, 14, 28, and 56 after application of DBTC or solvent, 10 mice in one group were killed at each time point respectively. Blood was obtained by inferior vena cava puncture. The activity of amylase, concentration of bilirubin and hyaluronic acid in serum were assayed. The pancreas was taken to observe the pancreatic morphology by HE staining, and to characterize the pancreatic fibrosis by Masson staining. The expression of F4/80, CD3 and fibronectin (FN) were assayed by immuno-histochemistry or Immunofluorescence technique. Collagen type I (COL1A1) in pancreas were detected by Western blot. The expression of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNA in the pancreas was assessed by real time PCR.

RESULTS: DBTC induced an acute edematous pancreatitis within 1 d. The dilated acini, scattered acinar cell necrosis, and inflammatory cells were found at day 7. Extensive infiltration with inflammatory cells following deposition of connective tissue was observed at day 14. At day 28, level of pancreatic fibrosis was aggravated. The pancreatic tissue was replaced by an extended interstitial fibrosis at the end of 2 mo. There was significant difference in the level of amylase, bilirubin and hyaluronic acid in serum between control group and model group (P < 0.05). The level of COL1A1 and FN in pancreas increased. The expression of MMP-1 mRNA in pancreas decreased, but TIMP-1 mRNA increased at model group.

CONCLUSION: DBTC joint Ethanol drinking can induce chronic pancreatitis in accordance with the pathophysiological modification of human. DBTC joint Ethanol-induced pancreatitis in mice is an effective and handy experimental method. The model is suitable to study the mechanism of pancreatic fibrosis in chronic pancreatitis.

Tanshinone IIA protects dopaminergic neurons against 6-hydroxydopamine-induced neurotoxicity through miR-153/NF-E2-related factor 2/antioxidant response element signaling pathway

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder with increased oxidative stress, the underlying vital process contributing to cell death. Tanshinone IIA (Tan IIA), a major bioactive diterpene quinone of Salva miltiorrhiza, had been proved effective in the MPTP model through its anti-inflammatory activity. Here in this research, we found that Tan IIA prevented the loss of nigrostriatal dopaminergic neurons by activating the NF-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway. The cytotoxicity of 6-hydroxydopamine (6-OHDA) was attenuated by the treatment of Tan IIA in SH-SY5Y cells, which significantly reduced 6-OHDA-induced lactic dehydrogenase release and reactive oxygen species production. Further study indicated that Tan IIA contributed to the nuclear accumulation of Nrf2, which bound to the ARE sequence, and activated ARE-regulated genes, including heme oxygenase-1, glutamate cysteine ligase catalytic subunit (GCLC) and glutamate cysteine ligase modifier subunit (GCLM). Tan IIA also protected against damage to mitochondrial membrane potential, reduced the translocation of cytochrome c from the mitochondria to the cytoplasm and the activation of Caspase-9 and Caspase-3. Moreover, we demonstrated the above effects were performed in Nrf2-dependent manner. Further studies revealed that Tan IIA reduced the enhancement of miR-153 by 6-OHDA, which targeted the 3'-UTR of Nrf2, and suppressed its expression and activation. Additionally, neurodegeneration caused by in vivo stereotaxic injection of 6-OHDA could also be ameliorated by the administration of Tan IIA. Taken together, our results strongly suggest that Tan IIA may be beneficial for the treatment of PD, and also confirm that targeting the Nrf2/ARE pathway is a promising strategy for therapeutic intervention in PD.

Plasma kinetics, excretion in milk of eprinomectin, and its efficacy against Hypoderma spp. following topical administration in yaks

The plasma pharmacokinetics and mammary excretion of eprinomectin were determined in dairy yaks following topical administration at a dose of 0.5 mg/kg. The kinetics of plasma and milk concentrations were analyzed using a noncompartmental model. Plasma and milk concentrations of eprinomectin increased to reach maximal concentrations of 5.45 ± 2.84 and 2.29 ± 0.90 ng/mL at a Tmax of 1.79 ± 0.57 and 2.00 ± 0.82 days, respectively. The concentration of eprinomectin in plasma was remained >0.5 ng/mL for more than 30 days after administration. The mean residence times of eprinomectin in plasma and milk were 14.73 ± 6.22 and 9.37 ± 2.81 days, respectively. The AUC value in plasma (55.89 ± 18.16 ng day/mL) was threefold greater than that in milk (18.02 ± 6.48 ng day/mL). The AUC milk/plasma ratio was 0.33 ± 0.08. The systemic availability of eprinomectin in yaks was lower than that observed value in other domestic bovines. The low level of eprinomectin excretion in milk suggests that eprinomectin can be used in yaks with zero milk-withdrawal time. The efficacy of eprinomectin against naturally acquired larvae of Hypoderma spp. was also determined in yaks. Topically administrated eprinomectin at a dose of 0.5 mg/kg was 100% efficacious against larvae of Hypoderma bovis, H. lineatum, and H. sinense.

Shikonin reduces endometriosis by inhibiting RANTES secretion and mononuclear macrophage chemotaxis

Endometriosis is a common disease in females of reproductive age and has the classic characteristic of mononuclear cell infiltration into lesions. Shikonin is an anti-inflammatory phytocompound obtained from Lithospermum erythrorhizon whose potential therapeutic effects in the treatment of endometriosis remain unclear. The working hypothesis of the present study was that shikonin is capable of inhibiting the development of endometriosis by inhibiting the chemotactic effect. In a murine model of endometriosis, shikonin significantly inhibited the growth of human endometrial tissue implanted into severe combined immunodeficiency (SCID) mice (P<0.05) and no adverse effects were observed. Mouse regulated upon activation normal T-cell expressed and secreted (mRANTES) levels in the peritoneal fluid of the animal endometriosis model were higher than those in normal SCID mice (P<0.05) and decreased significantly following shikonin treatment in a dose-dependent manner (P<0.05). Peritoneal fluid from SCID mice treated with shikonin inhibited the chemotaxis of monocytes; this inhibitory effect was eradicated by mRANTES antibody. In vitro, shikonin significantly inhibited RANTES expression in U937 cells that were cultured alone or co-cultured with human mesothelial and endometrial stromal cells. In addition, shikonin inhibited the RANTES-induced chemotaxis of U937 cells (P<0.05). The results indicate that shikonin inhibits the development of endometriosis by various mechanisms, including the inhibition of RANTES expression and the reduction of mononuclear cell migration to lesions. Therefore, shikonin may be a novel, useful and safe agent for treating endometriosis.

Downregulation of miR-183 inhibits apoptosis and enhances the invasive potential of endometrial stromal cells in endometriosis

Endometriosis is a common gynecological disease, yet its pathogenesis remains poorly understood. Recent studies have demonstrated that the aberrant expression of certain microRNAs (miRNAs) may correlate with the development and progression of endometriosis. In this study, we profiled several differentially expressed miRNAs in the normal, eutopic and ectopic endometrium by miRNA microarray screening analysis, among which, miR-183 was found to be downregulated in the ectopic and eutopic tissues, and the result was further confirmed by real-time PCR (qPCR). Functional analysis indicated that miR-183 plays a promotional role in endometrial stromal cell (ESC) apoptosis and has a negative regulatory impact on the invasive ability of cells, although it has no effect on ESC proliferation. Ovarian steroids (17β-estradiol and progesterone) and inflammatory factors (tumor necrosis factor-α and interleukin-6) decreased the expression of miR-183 in the ESCs. This regulatory function may further manifest the growth and invasive potential of ESCs by altering the expression of miR-183. These findings suggest that the downregulation of miR-183 expression is involved in the development and progression of endometriosis.

The high level of RANTES in the ectopic milieu recruits macrophages and induces their tolerance in progression of endometriosis

RANTES (C-C chemokine, regulated on activation, normal T cell expressed and secreted) is involved in progression of endometriosis, but the precise mechanism is understood inadequately. This study is to elucidate the roles of RANTES in macrophage recruitment and tolerance in the endometriotic milieu. The expression of RANTES was analyzed by immunohistochemistry. The cell co-cultures were applied to simulate the endometriotic milieu to investigate the regulation of RANTES secretion and its receptor CCR1 expression. Transwell migration assay was used for chemotaxis of U937 cells (macrophage line) to endometrial stromal cells (ESCs) and/or human pelvic mesothelial cells. The expression of CCR1 was analyzed by RT-PCR and qPCR in transcription and by western blot in translation respectively. Concentrations of RANTES, IL10, and IL12p70 were determined by ELISA. The phenotype of U937 cells and apoptosis of ESCs were analyzed by flow cytometry. We have found that the expression of RANTES is significantly higher in the endometriotic tissue and eutopic endometrium than that of the normal endometrium without endometriosis. The combination of 17β-estradiol and dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin increases significantly RANTES secretion in the endometriosis-associated cell co-culture which can recruit more macrophages, upregulate CCR1 expression, and induce tolerant phenotype, which inhibits the apoptosis of ESC in the milieu. In conclusion, the higher levels of RANTES in the ectopic milieu facilitate the onset and progression of endometriosis by macrophage recruitment and tolerance that in turn inhibits apoptosis and enhances growth of ESC.

Specific PCR-based assays for the identification of Fasciola species: their development, evaluation and potential usefulness in prevalence surveys

Among the helminths infecting ruminants in China are three taxa belonging to the genus Fasciola: F. hepatica, F. gigantica and the so-called 'intermediate form' that appears to lie between these two species. Based on the sequences of the second internal-transcribed spacers (ITS-2) within the parasites' nuclear ribosomal DNA (rDNA), a pair of primers (DSJf/DSJ3) specific for F. hepatica and a pair (DSJf/DSJ4) specific for F. gigantica were designed and used to develop PCR-based assays. These assays allowed the identification and differentiation of F. hepatica, F. gigantica and the 'intermediate' Fasciola, with no amplicons produced from heterologous DNA samples. The results of sequencing confirmed the species-specific identity of the amplified products. The assays showed good sensitivity, giving positive results with as little as 0.11 ng of F. hepatica DNA and 0.35 ng of F. gigantica DNA. This meant that the DNA from a single Fasciola egg or a single infected snail was sufficient for identification of the Fasciola taxon. The developed PCR assays could provide useful tools for the detection, identification and epidemiological investigation of Fasciola infection in humans, other mammals and snails.

Search for new half-metallic ferromagnets in zinc blende CaSi and CaGe by first-principles calculations

We present an investigation on the electronic structure and ferromagnetism for the hypothetical zinc blende (ZB) CaSi and CaGe by using first-principles full-potential linearized augmented plane-wave (FP-LAPW) calculations. It is found that ZB CaSi and CaGe are half-metallic (HM) ferromagnets without any transition-metal component; they have a magnetic moment of 2.000 µ(B) per formula unit. Analysis of the density of states and magnetic moment indicates that their magnetism mainly originates from the spin polarization of anion p states and the hybridization between the anion p states and the Ca d states. We also find that the half-metallicity can be maintained even when the lattice constant of ZB CaSi and CaGe is compressed up to 8% and 5%, respectively. The absence of the transition-metal atoms makes ZB CaSi and CaGe attractive not only as materials for possible spintronics devices but also as model objects for the study of new mechanisms of the formation of half-metallic ferromagnetism in s-p electron systems.

Combination of 17β-estradiol with the environmental pollutant TCDD is involved in pathogenesis of endometriosis via up-regulating the chemokine I-309–CCR8

OBJECTIVE

To explore the effects of the combined E(2) with the environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on CCR8-I-309 expression by the endometriotic lesion-associated cells in the pathogenesis of endometriosis.

DESIGN

Prospective laboratory study.

SETTING

University hospital.

PATIENT(S)

Chinese women with endometriosis.

INTERVENTION(S)

The endometriotic tissue and matched eutopic endometrium were collected. Endometrial stromal cells (ESCs), HPMC, and U937 cells were treated with 17beta-E(2) or TCDD. The ESCs were stimulated with I-309.

MAIN OUTCOME MEASURE(S)

The expression of CCR8 in tissues was analyzed by reverse transcription-polymerase chain reaction and immunohistochemistry. The effect of I-309 on integrin beta1 and alphavbeta3 expression intensity was analyzed by flow cytometry, and the chemotactic activity of I-309 on the ESC was explored by chemotactic assay. Concentration of I-309 in the culture supernatant was quantified by enzyme-linked immunosorbent assay.

RESULT(S)

CCR8 was overexpressed in the endometriotic tissue. I-309 promoted the expression of integrin beta1. Estradiol and TCDD up-regulated CCR8 expression by ESCs. Estradiol magnified the stimulatory effect of TCDD on I-309 secretion by U937. The interaction of HPMC and U937 cells promoted I-309 secretion.

CONCLUSION(S)

These findings imply that the combination of 17beta-E(2) with the environmental pollutant TCDD is involved in the pathogenesis of endometriosis via up-regulating the chemokine CCR8-I-309.

Effects of combined 17beta-estradiol with TCDD on secretion of chemokine IL-8 and expression of its receptor CXCR1 in endometriotic focus-associated cells in co-culture

BACKGROUND

Chemokines play an important role in the pathogenesis of endometriosis. In the present study, the transcription of 18 chemokine receptors in eutopic endometrium and ectopic tissue with endometriosis was first analysed by RT-PCR. Dioxin, an air pollutant, and estrogen are reported to be associated with endometriosis. The regulatory mechanisms of dioxin and estrogen in the expression of CXCR1/IL-8 in the corresponding cells will help in elucidating roles of the chemokine in the aetiology of endometriosis.

METHODS AND RESULTS

CXCR1, a type of chemokine receptor, was over-expressed in endometriotic tissue. The high translation of the receptor and its ligand, interleukin (IL-8), in endometriotic tissue was then demonstrated by immunochemistry. Estradiol and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alone inhibited expression of CXCR1, whereas the combination of estradiol with TCDD up-regulated the expression. TCDD promoted IL-8 secretion by human pelvic mesothelial cells (HPMC), and 17beta-estradiol magnified the stimulatory effect. Both 17beta-estradiol and TCDD alone inhibited IL-8 secretion of U937 (a cell line of monocyte), but combination of 17beta-estradiol and TCDD had no further inhibitory effect. The co-culture of endometrial stromal cells (ESC) with HPMC produced more IL-8 than respective or total production of either of the cells alone, and estradiol played a synergistic stimulatory role with TCDD in IL-8 secretion of the co-culture. Interaction of HPMC and the monocytes significantly stimulated IL-8 secretion, suggesting a main resource of IL-8 in peritoneal cavity with endometriosis. TCDD promoted IL-8 secretion by HPMC-U937 co-culture, but exerted a contrary effect for IL-8 secretion when combined with estradiol.

CONCLUSION

Estradiol and TCDD in the peritoneal cavity can lead to a persistent and serious inflammation, which gives a new insight into the interactions of estrogen and TCDD in endometriosis.

The Effect of the Water Content of Acetonitrile on the Electrochemistry of Ferrocenyl Thiol Self-Assembled Monolayers

A novel kind of ethylene-ferrocenyl dodecyl thiol bearing an electron-withdrawing pyridium group (FcCH=CH-Py(CH2)10SH) was synthesized and mixed with HOOCC(10)SH on an Au electrode to form mixed self-assembled monolayers (SAMs) in ethanol solution. The influence of the water content of acetonitrile on the electrochemistry of the SAMs was studied by cyclic voltammetry and ac voltammetry measurement. The results showed that the current decreased and the oxidation potential of the ferrocene group shifted negatively with increasing water content of acetonitrile.

Different effects of toosendanin on perineurially recorded Ca(2+) currents in mouse and frog motor nerve terminals

By perineurial recording, the effects of toosendanin (TSN), a presynaptic blocker, on nerve terminal calcium currents (I(Ca)) were observed in innervated triangularis sterni of the mouse and cutaneous pectoris of the frog. It was found that TSN blocked the slow component of I(Ca) insensitive to nifedipine and omega-conotoxin-GVIA, and increasing the extracellular Ca(2+) concentration partially antagonized the inhibitory effect in mouse motor nerve terminals. However, in the frog, TSN increased the slow component of I(Ca) and this effect disappeared in the presence of nifedipine in perfusion solution. Based on previous data showing that the slow component of I(Ca) were mediated by different subtypes of calcium channels in mouse and frog motor nerve terminals, we presume that TSN could exercise different effects on various subtypes of calcium channels.

A patch-clamp study on human sperm Cl- channel reassembled into giant liposome

AIM

To record the single-channel currents and characterize the electrophysiological properties of the Cl- channels in human sperm membrane.

METHODS

The membrane proteins extracted from the human sperm were reassembled into liposome bilayer, and the liposomes were fused into giant liposomes with a diameter more than 10 microm by dehydration-rehydration procedure. The giant liposomes were used to study the Cl- channel activities by patch-clamp technique.

RESULTS

By patch clamping the giant liposome in an asymmetric NMDG (N-methyl-D-glucamine)-Cl (bath 100// pipette 200 mmol/L) solution system, three kinds of single-channel events with unit conductances of (74.1 +/- 8.3) pS, (117.0 +/- 5.7) pS and (144.7 +/- 4.5) pS, respectively, were detected. Their activities were voltage-dependent and all were blocked by SITS (4-acetamido-4'-isothiocyanato-stilbene-2', 2'-disulfonic acid) in a concentration-dependent manner. By constructing the open and close dwell time distribution histograms and then fitting them with exponential function, two time constants were obtained in both the open and the close states. The burst activity and conductance substate of the channels were observed.

CONCLUSION

There exist three kinds of Cl- channels with different conductance in human sperm membrane at least.

Sodium current in NG108-15 cell inhibited by scorpion toxin BmKAS-1 and restored by its specific monoclonal antibodies

Effect on Na+ current of BmKAS-1, a novel polypeptide purified from the venom of Chinese scorpion Buthus martensi Karsch (BmK), has been investigated in differentiated NG108-15 cells by using patch-clamp whole-cell recording. Neutralizing effect of four monoclonal antibodies of BmKAS-1 (mAb #2, #3, #4, and #5) has also been observed. The results showed that Na+ current was irreversibly inhibited by BmKAS-1 and the inhibitory effect was abolished by mAb #2 and #5, but not by mAb #3 and #4.

[Hemorrhagic shock induces changes in large-conductance Ca(2+) dependent K+ channel activity in mesenteric arterial smooth muscle cells of rats]

The purpose of the present study was to detect changes in the activity of large-conductance Ca(2+)activated K(+) channel (BK(Ca)) during hemorrhagic shock (HS) in mesenteric arterial vascular smooth muscle cells using inside-out patches. The HS rat model was produced with withdrawing blood from the femoral artery. The results showed that the BK(Ca) activity was inhibited with decreased open probability (P(o)) and single-channel conductance. The decrease of P(o) resulted from an increase of the close time constant (tau(cs)) in the compensatory stage of HS, i.e.the term of hyperresponse of the muscle to norepinephrine (NE) (HS lasted for about 40 min). During the decompensation stage of HS, i.e. the period of hyporesponse to NE (HS developed for 3 h), the BK(Ca) activity was enhanced with the increase in single-channel conductance and P(o) which was a result of a decrease in tau(cs).

Inhibition of large-conductance Ca(2+)-activated K(+) channels in hippocampal neurons by toosendanin

The effect of toosendanin, a selective presynaptic blocker and effective antibotulismic agent, on large-conductance Ca(2+)-activated K(+) channels was studied in inside-out patches of pyramidal neurons freshly isolated from the hippocampal CA1 region of the rat. Toosendanin (1 x 10(-6)g/ml approximately 1 x 10(-4)g/ml) was found to inhibit large-conductance Ca(2+)-activated K(+) channels by reducing its open probability significantly in a concentration-dependent manner, although the effective concentration of toosendanin was lower in a symmetrical K(+) (150 mM) solution than under asymmetrical conditions (changing K(+) concentration in pipette solution to 5mM). The action was partially reversible by washing. By decreasing the slow open time constant, toosendanin shortened the open dwell time of large-conductance Ca(2+)-activated K(+) channels in a dose-dependent manner. A dose-dependent reduction of unitary current amplitude of the channel was detected after toosendanin perfusion. On elevating the intracellular free calcium concentration from 1 to 10 microM, a similar effect on large-conductance Ca(2+)-activated K(+) channels by toosendanin was also observed, but its efficacy was diminished. These results show that toosendanin inhibits large-conductance Ca(2+)-activated K(+) channels in hippocampal neurons by reducing the open probability and unitary current amplitude of the channel, and that Ca(2+) interferes with the effect. These data provide an explanation for toosendanin-induced facilitation of neurotransmitter release and the antibotulismic effect of the drug.

Modulation of inward rectifier potassium channel by toosendanin, a presynaptic blocker

The effect of toosendanin, a presynaptic blocker, on the inward rectifier potassium channel (K(Kir)) of hippocampal CA1 pyramidal neurons of rats was studied by the single-channel patch-clamp technique. The results showed that toosendanin had an inhibitory effect on K(Kir) in an excised inside-out patch of the neuron under a symmetrical 150 mM K(+) condition. By decreasing the slower open time constant and increasing the slower close time constant, toosendanin (1x10(-6)-1x10(-4) g/ml) significantly reduced the open probability of the channel in a concentration-dependent manner. Meanwhile, a dose-dependent reduction in unitary conductance of the channel was also detected after toosendanin application. These data offer an explanation for toosendanin-induced facilitation of neurotransmitter release and antibotulismic effect of the drug.

Toosendanin-induced inhibition of small-conductance calcium-activated potassium channels in CA1 pyramidal neurons of rat hippocampus

The effect of toosendanin (TSN) on small-conductance calcium-activated potassium channels (SK(Ca)) in pyramidal neurons of rat hippocampal CA1 region was observed using the inside-out configuration of patch-clamp technique. The results showed that TSN (1.7 approximately 170 microM) inhibited the SK(Ca) activity by reducing the open probability and open frequency significantly in a concentration-dependent manner, and the effects were partially reversible. Elevating Ca2+ concentration at the intracellular side of the patch ([Ca2+](i)) from 1 to 10 microM decreased the inhibitory efficacy. Analysis of the channel kinetics indicated that TSN increased the slow closed time constant significantly, while open time and unitary conductance of channel did not change. These data provide a further explanation for TSN-induced facilitation of neurotransmitter release and antibotulismic effects of the drug.

[Induction of protective immune responses in rhesus monkey by immunization with recombinant plasmids of polyvalent epitopes of Plasmodium falciparum using cholera toxin B as adjuvant]

The immunogenicity and protective efficacy of the DNA vaccine which include cholera toxin B subunit (CTB) and polyvalent protective epitopes of Plasmodium falciparum (awte gene) was assessed using rhesus monkeys as animal models. Recombinant plasmids of pCMV-CTB-AWTE were given to five rhesus monkeys three times with two weeks intervals by intramuscle (i.m.) route, immunization dose was 500 micrograms per plasmid per animal. High levels of anti-CTB and anti-malaria epitopes antibodies and P. falciparum epitope specific CTL activity were elicited. The vaccinated groups was challenged with 1.25 x 10(8) of P. cynomolgi parasites. All monkeys of the control group was patent for at least 34 days, the DNA vaccinated groups wasn't infected during the 60 days we detected. The cocktail DNA vaccine which contains multi-stage and multi-epitope antigen gene shows excellent immunogenicity and protective efficacy, the results also suggests that DNA vaccine plays an important role against malaria infection.

[Induction of protective immune response in mice and rhesus monkeys by immunization with fusion protein of cholera toxin B subunit and multiples of Plasmodium falciparum]

Recombinant fusion protein of cholera toxin B subunit (CTB) and poly-valent protective epitopes of plasmodium falciparum was given to i.m. to C57BL/6j mice and rhesus monkeys three times. In rhesus monkeys, high level of antibodies for CTB (1:6400) and malaria epitopes (1:3200) amtobpdoes were elicited as well as the specific CTL activity for P. plasmodium. After the mice were challenged with sporozoites of P. yeolli, about 50% of them were protected from the patent infection. A blood-stage challenge with 10(8) of P. cynomolgi parasite were given to rhesus monkeys, which showed that two animals in control group were patent infection for at least 30 days, in contrast, the two animals immunized were recovered respectively at the day of 11 and 15 after challenges. The results suggested that cholera toxin acts as an effective adjuvent in the development of malaria vaccine.

Synthesis and antimalarial activity of artemisinin derivatives containing an amino group

In search of water-soluble artemisinin derivatives that are more stable than sodium artesunate, over 30 derivatives containing an amino group (compounds 3-5) were synthesized and tested in mice. All products tested (except 5a and 5b) are the beta isomers. These basic compounds combined with organic acids (oxalic acid, maleic acid, etc. ) to yield the corresponding salts. Generally, the maleates have better solubility in water than the corresponding oxalates. The aqueous solutions of these salts can be kept at room temperature for several weeks without any discernible decomposition. Compounds 3f, 3h, and 3r are much more active against P. berghei than artesunic acid by oral administration and therefore were further tested in monkeys. However, their oral efficacies are poorer than that of artesunic acid against P. knowlesi in rhesus monkeys. It is interesting to note that 3f, 3h, and 3r showed much lower efficacies against P. berghei when they were administered subcutaneously than orally.

Beta-agkistrodotoxin inhibits fast and Ca2+-activated K+ currents recorded from mouse motor nerve terminals

Beta-agkistrodotoxin (beta-AgTx), a polypeptide purified from the venom of Agkistrodon blomhoffii brevicaudus, is a presynaptic blocker acting on neurotransmitter release. In this work, perineural recording technique was employed to study the effects of beta-AgTx on sodium, potassium and calcium currents of mouse motor nerve terminals. The results showed that beta-AgTx selectively inhibited Ca2+-dependent (I(K,Ca)) and fast (I(K,f) K+ currents, but did not affect slow K+ current (I(K,s)), sodium and calcium currents. However there are other components in A. blomhoffii brevicaudus venom which inhibit perineural sodium current. The present data have provided additional evidence that the site of action of beta-AgTx is different from that of beta-bungarotoxin.

[Growth and metabolism of hybridoma cells in semicontinuous perfusion cultures]

The growth and metabolism of WuT3 hybridoma cells were studied in semicontinuous perfusion cultures. The growth of cells, utilization of glucose, production of lactate, ammonia and monoclonal antibody were investigated. As the perfusion rate increased from 1.0/d to 2.0/d, the lactate yield coefficient from glucose Ylac/glu decreased 18%, the ammonia yield coefficient from glutamine Yamm/gln decreased 40%, the alanine yield coefficient from glutamine Yala/gln increased 58%, the glycine yield coefficient remained almost constant. This indicate that cells would regulated their metabolic flux at higher cell density, and glutamate produced in quantity and pyruvate would turn into alanine rather than glycine by transamination. As a result, potentially toxic effects were reduced because less ammonia and lactate were produced.

Effect of Toosendanin on acetylcholine level of rat brain, a microdialysis study

The effect of prejunctional blocker Toosendanin (TSN) on acetylcholine (ACh) level in striatum and parietal cortex was investigated by means of method of brain dialysis coupled with microbore high-performance liquid chromatograph (HPLC)-electrochemical detection (ECD) with enzyme immobilized post-column at freely moving rats. The results are as follows: (1) TSN inhibits high K+ (100 mM)-induced ACh release from the mentioned two regions of brain, completely and irreversibly. (2) Before the inhibition, there appears a transient rise of ACh level. (3) This rise of ACh level can be blocked by TTX. (4) Calcium is necessary for the onset of this rise, but not for that of the sustained decrease of ACh level. These results indicate that the effect of TSN on central cholinergic synapses is similar to that of neuromuscular junction, namely, its blocking action is always preceded by a Ca(2+)-dependent facilitatory phase with result of a TSN-induced transient rise of ACh, but the sustained decline and final blockade of ACh release are Ca(2+)-independent.

A patch clamp study on reconstituted calcium permeable channels of human sperm plasma membranes

Ionic flux is thought to be important in the initiating process of gamete interaction such as acrosome reaction. However, modern electrophysiological methods, intracellular recording and patch-clamping, are difficult to approach the ion channels in mammal sperm membrane of an intact sperm due to its small size. In this work, by reconstituting the channel protein into lipid bilayer, Ca2+ channels in human spermatozoa were investigated with voltage clamp technique. Membrane proteins isolated from human sperm of 12 healthy donors were incorporated into lipid bilayer via fusion. In a cis 50//trans 10 mmol/L CaCl2 solution system, two types of channel events with similar reversal potential near the value of a perfect Ca2+ electrode, and sensitive to nifedipine and verapamil, were observed. Their unit conductance was 40 and 25 pS respectively. Percentage of channel open time was not dependent to holding potential for the former. However, for the channels of 25 pS, the percentage increased when the holding potential was changed from -20 to 100 mV. Ca(2+)-permeable channels were also detected from the spermatozoon samples of two infertile donors. Abnormal open time of these channels indicates that there are some defects in the conformation of the channel protein of infertile sperm membrane.

Cation channel formed at lipid bilayer by Cinnamomin, a new type II ribosome-inactivating protein

Cinnamomin, a new type II ribosome-inactivating protein, purified from the seeds of Cinnamonum camphora is reconstituted into the membranes of planar lipid bilayer and giant liposome. The channel-forming activity of the cinnamomin is found and cation permeability of the channel is characterized by patch clamp. In an asymmetric solution system, bath 150/pipette 100 mM KCl, the unit conductance is 140+/-7 pS and the reversal potential is 10.4+/-0.6 mV, very close to the theoretical value of the K+ electrode. The results offer an interpretation for internalization of the RIP and the cytotoxicity difference between single and two chain RIP.

Schizontocidal effects of oral artesunate on Plasmodium berghei in mice and P knowlesi in monkeys

AIM

To study the blood schizontocidal effect of oral artesunate on P berghei in mice and P knowlesi in monkey.

METHODS

Effects of artesunate and chloroquine were detected with "4-day test" and "28-day test" on P berghei in mice and "7-day test" on P knowlesi in Macaca mudatta.

RESULTS

The suppressive efficacy of oral artesunate was inferior to chloroquine on P berghei K173 strain but the time for 50% and 90% reduction and the time of clearance of parasitemia was 10-15 h shorter than that of chloroquine. Its curative effect on RC/K173 line was markedly superior to that of chloroquine. Moreover, artesunate showed no cross-resistance with chloroquine, index of resistance I90 was only 1.4. At 31.6, 10.0, and 3.16 mg.kg-1, artesunate and chloroquine oral administrations cured P knowlesi in all monkeys. Recrudescence did not occur in 105 d.

CONCLUSION

The study of effects of oral artesunate in P berghei/mice and P knowlesi/Macaca mulatta model provided a useful index for clinical trial.

Ion-channels reconstituted into lipid bilayer from human sperm plasma membrane

Ion environment and ionic fluxes through membrane are thought to be important in the spermatozoa's maturation, capacitation, and the initiating process of gamete interaction. In this work, the membrane proteins isolated from human sperm plasma membrane were reconstituted into planar lipid bilayers via fusion, and the ion channels activities were observed under voltage clamp mode. In cis 200//trans 100 mM KCl solution, a TEA-sensitive cation-selective channel with a unit conductance of 40 pS was recorded. In a gradient of 200//100 mM NaCl solutions, a Na(+)-selective channel with a unit conductance of 26 pS was recorded. In both cases, reversal potential was about-18 mV, which is close to the predicated value of a perfect Nernst K+ or Na+ electrode. In 50//10 mM CaCl2 solution, a cation channel activity with a unit conductance of 40 pS and reversal potential of about -20 mV was usually observed. In 200//100 mM NMDG(N-methyl-D-glucamine)-Cl solution, where the cation ions were substituted with NMDG, a 30-pS anion-selective channel activity was also detected. The variety in the types of ion channels observed in human spermatozoa plasma membrane suggests that ion channels may play a range of different roles in sperm physiology and gamete interaction.

[Ion channels of mammalian and human sperm membrane]

Ionic fluxes are thought to be important for sperm physiology. In recent years, using artificial membrane reconstitution and voltage clamp technique, different populations of ion channels, including K+, Na+, Ca2+ and Cl- channel, in mammalian and human sperm membrane were investigated. These studies shed lights to the understanding of some ionic basis underlying some mechanisms of sperm maturation, capacitation and gamete interaction. The results on human sperm ion channels also give us a chance to take it into clinic utility.

[The inhibitory effects of artemisinin-derivatives on Na+ and K+ channels in comparison with those of procaine]

Some derivatives of artemisinin have been shown to have local anesthesia action. By using patch-clamp whole cell recording configuration, the effects of five artemisinin-derivatives on the voltage-gated INa and IK have been studied on differentiated NG108-15 cells with reference to procaine. The results showed that all the five artemisinin-derivatives clearly inhibited the voltage-gated sodium current (INa) of the cells in a dose-dependent manner and the effect was partially reversibly. Among the five artemisinin-derivatives, SM541 has been shown to be most potent, approaching that of procaine. However, 300 mumol/L procaine showed only a slight inhibition of IK, whereas all the five derivatives at the same concentration not only decreased IK clearly, but also accelerated its inactivation. Except for SM541, the inhibitory effects on IK decreased rapidly with perfusion of the rest 4 derivatives.

Effects of ADP, DTT, and Mg2+ on the ion-conductive property of chloroplast H+-ATPase(CF0-CF1) reconstituted into bilayer membrane

The purified CF0-CF1 complex of spinach was incorporated into planar lipid bilayer membranes (LBMs) formed with soybean phospholipid, and the transmembrane ion-transmission properties were studied under voltage-clamp mode. The results showed that the presence of both ADP and Pi decreased the membrane current while Dithiothreitol could evoke a stronger conductive change of CF0-CF1 containing LBMs when Ca2+ or Mg2+ exists. Mg2+ can dramatically increase the CF0-CF1 conductance in various conditions. These results indicated that the H(+)-transitive function of CF0-CF1 reconstituted in bilayer is sensitive to those factors which can affect its ATP synthase activity in vivo.

Characterization of an inward-rectifying potassium current in NG108-15 neuroblastoma x glioma cells

By using the whole-cell patch-clamp technique, an inwardly rectifying potassium current, which resembled the "classic" inward-rectifying potassium current (IKIR) of other cells in terms of electrophysiological and pharmacological properties, was identified in db-cAMP-differentiated NG108-15 cells. First, the current was dependent on voltage and time. It could be elicited by applying an initial depolarizing prepulse and a subsequent hyperpolarizing command pulse to the cell. The amplitude of the current depended on both the prepulse and the command pulse and increased with the hyperpolarization of the command pulse as well as the depolarization and the prolongation of the prepulse. The activation and inactivation of the current could be fitted well by single-exponential functions and increased with the hyperpolarization of the membrane. Second, the current was dependent on the extracellular potassium concentration ([K+]o). Elevation of [K+]o resulted in a marked increase in the current amplitude and a positive shift of the peak-current/voltage curve as well as the reversal potential. A tenfold increase of [K+]o introduced an approximately 43-mV shift of the reversal potential, indicating that the current was carried mainly by K+. The conductance (g/gMax) of the current was also dependent on the [K+]o and increased with increases in [K+]o in a manner approximately proportional to the square-root of [K+]o. Finally, the current was sensitive to Cs+ (1 mmol/l), Ba2+ (1 mmol/l) and quinidine (0.2 mmol/l); whereas, two typical potassium channel inhibitors, tetraethylammonium (TEA) and 4-aminopyridine (4-AP), were weak blockers and reduced the current at high concentration (>10 mmol/l). It was also observed that the current was depressed by Cd2+ (1 mmol/l) and Co2+ (1 mmol/l) and increased by perfusing the cell with Ca2+-free solution. Thus, except for the sensitivity to Cd2+, Co2+ and Ca2+, the current displayed most of the hallmarks described for the "classic" IKIR. In conclusion, there appears to be a voltage-dependent IKIR-type inward rectifier in db-cAMP-differentiated NG108-15 cells.

Cation and anion channels in rat and human spermatozoa

Ionic fluxes are thought to be important in the initiating process of gamete interaction such as acrosome reaction. Different populations of ion channels in rat and human spermatozoa were investigated using the planar lipid bilayer technique. Membrane proteins were isolated from rat and human sperm and inserted into lipid bilayer via fusion. We observed K(+) selective and Na(+)-selective channels, as well as divalent permeable cation channels in membrane preparations from rat sperm K+ channels, which were sensitive to the K+ channel blocker, tetraethylammonium (0.1 mM), exhibited a mean single channel conductance of 24 pS. Whereas, larger conductance, 109 pS, was found to be associated with Na+ channels. Low conductance anion channel, 15 pS, was also observed when permeant cations in the bathing solutions were substituted with N-methyl-D-glucamine leaving Cl- as the major permeant ion species. This channel exhibited a slower channel open and closed kinetics when compared to other cation channels. Both cation and anion channels with characteristics similar to that found in rat sperm were also observed in preparations from human sperm. The variety in the types of ion channels observed in rat and human spermatozoa suggests that ion channels may play different roles in sperm physiology and gamete interaction.