Role of a novel circRNA-CGNL1 in regulating pancreatic cancer progression via NUDT4-HDAC4-RUNX2-GAMT-mediated apoptosis

BACKGROUND

Pancreatic cancer (PC) is an extremely malignant tumor with low survival rate. Effective biomarkers and therapeutic targets for PC are lacking. The roles of circular RNAs (circRNAs) in cancers have been explored in various studies, however more work is needed to understand the functional roles of specific circRNAs. In this study, we explore the specific role and mechanism of circ_0035435 (termed circCGNL1) in PC.

METHODS

qRT-PCR analysis was performed to detect circCGNL1 expression, indicating circCGNL1 had low expression in PC cells and tissues. The function of circCGNL1 in PC progression was examined both in vitro and in vivo. circCGNL1-interacting proteins were identified by performing RNA pulldown, co-immunoprecipitation, GST-pulldown, and dual-luciferase reporter assays.

RESULTS

Overexpressing circCGNL1 inhibited PC proliferation via promoting apoptosis. CircCGNL1 interacted with phosphatase nudix hydrolase 4 (NUDT4) to promote histone deacetylase 4 (HDAC4) dephosphorylation and subsequent HDAC4 nuclear translocation. Intranuclear HDAC4 mediated RUNX Family Transcription Factor 2 (RUNX2) deacetylation and thereby accelerating RUNX2 degradation. The transcription factor, RUNX2, inhibited guanidinoacetate N-methyltransferase (GAMT) expression. GAMT was further verified to induce PC cell apoptosis via AMPK-AKT-Bad signaling pathway.

CONCLUSIONS

We discovered that circCGNL1 can interact with NUDT4 to enhance NUDT4-dependent HDAC4 dephosphorylation, subsequently activating HDAC4-RUNX2-GAMT-mediated apoptosis to suppress PC cell growth. These findings suggest new therapeutic targets for PC.

Retrospective analysis of medical emergencies in an oral emergency department

BACKGROUND

To retrospectively analyze the rescue of medical emergencies and critical patients in the oral emergency department in a hospital during the past 14 years; analyze the general condition of patients, their diagnosis, etiological factors, and outcomes of the disease, so as to improve the ability of oral medical staff to deal with emergencies; and optimize the emergency procedures and resource allocation in such departments.

MATERIAL AND METHODS

Data and related information of critical patient emergency rescue from the Emergency Department of the Hospital of Stomatology, Peking University from January 2006 to December 2019, were analyzed.

RESULTS

A total of 53 critical patients were rescued in the oral emergency department in the past 14 years, which is an average of four cases per year, with an incidence rate of 0.00506%. The main type of emergency included hemorrhagic shock and active hemorrhage, with the highest incidence being in the age group of 19-40 years old. Among these cases, 67.92% (36/53) developed emergency and critical diseases before visiting the oral emergency department and 41.51% (22/53) had systemic diseases. After rescue, a total of 48 patients (90.57%) had stable vital signs and 5 (9.43%) died.

CONCLUSIONS

Oral doctors and other medical staff should be able to rapidly identify medical emergencies in oral emergency departments and commence emergency treatment. The department should be equipped with relevant first-aid drugs and devices, and medical staff should be regularly trained in practical first-aid skills. Patients with oral and maxillofacial trauma, massive hemorrhage and systemic diseases should be evaluated and treated according to their conditions and systemic organ function to prevent and reduce medical emergencies.

Comparison between ozone column depths and methane lifetimes computed by one- and three-dimensional models at different atmospheric O2 levels

Recently, Cooke et al. (Cooke et al. 2022 R. Soc. Open Sci. 9, 211165. (doi:10.1098/rsos.211165)) used a three-dimensional coupled chemistry-climate model (WACCM6) to calculate ozone column depths at varied atmospheric O₂ levels. They argued that previous one-dimensional (1-D) photochemical model studies, e.g. Segura et al. (Segura et al. 2003 Astrobiology 3, 689-708. (doi:10.1089/153110703322736024)), may have overestimated the ozone column depth at low pO₂, and hence also overestimated the lifetime of methane. We have compared new simulations from an updated version of the Segura et al. model with those from WACCM6, together with some results from a second three-dimensional model. The discrepancy in ozone column depths is probably due to multiple interacting parameters, including H₂O in the upper troposphere, lower boundary conditions, vertical and meridional transport rates, and different chemical mechanisms, especially the treatment of O₂ photolysis in the Schumann-Runge (SR) bands (175-205 nm). The discrepancy in tropospheric OH concentrations and methane lifetime between WACCM6 and the 1-D model at low pO₂ is reduced when absorption from CO₂ and H₂O in this wavelength region is included in WACCM6. Including scattering in the SR bands may further reduce this difference. Resolving these issues can be accomplished by developing an accurate parametrization for O₂ photolysis in the SR bands and then repeating these calculations in the various models.

Raman spectroscopy and machine learning for the classification of esophageal squamous carcinoma

Early diagnosis of esophageal squamous cell carcinoma (ESCC), a common malignant tumor with a low overall survival rate due to metastasis and recurrence, is critical for effective treatment and improved prognosis. Raman spectroscopy, an advanced detection technology for esophageal cancer, was developed to improve diagnosis sensitivity, specificity, and accuracy. This study proposed a novel, effective, and noninvasive Raman spectroscopy technique to differentiate and classify ESCC cell lines. Seven ESCC cell lines and tissues of an ESCC patient with staging of T3N1M0 and T3N2M0 at low and high differentiation levels were investigated through Raman spectroscopy. Raman spectral data analysis was performed with four machine learning algorithms, namely principal components analysis (PCA)- linear discriminant analysis (LDA), PCA-eXtreme gradient boosting (XGB), PCA- support vector machine (SVM), and PCA- (LDA, XGB, SVM)-stacked Gradient Boosting Machine (GBM). Four machine learning algorithms were able to classifiy ESCC cell subtypes from normal esophageal cells. The PCA-XGB model achieved an overall predictive accuracy of 85% for classifying ESCC and adjacent tissues. Moreover, an overall predictive accuracy of 90.3% was achieved in distinguishing low differentiation and high differentiation ESCC tissues with the same stage when PCA-LDA, XGM, and SVM models were combined. This study illustrated the Raman spectral traits of ESCC cell lines and esophageal tissues related to clinical pathological diagnosis. Future studies should investigate the role of Raman spectral features in ESCC pathogenesis.

[Development and functional validation of a nano-delivery system of miR-16/polypeptide targeting ovarian cancer cells]

OBJECTIVE

To develop a nano-delivery system for targeted delivery of miR-16/polypeptide for enhancing cisplatin sensitivity of ovarian cancer.

OBJECTIVE

R9-SS-R9 and cRGD-R9-SS-R9 peptides were synthesized and self-assembled with miR-16 molecules to form a nano-delivery system. The stability, particle size, potential and morphology of the nanoparticles were determined by agarose gel electrophoresis, particle size potentiometer and transmission electron microscopy. CCK-8 assay was used to assess the toxicity of the polypeptides in ovarian cancer cells. Stem loop qRT-PCR and living cell imaging were used to verify the uptake efficiency and intracellular distribution of the nanoparticles. Flow cytometry and Western blotting were performed to verify the effect of the nanoparticles for enhancing cisplatin sensitivity of ovarian cancer cells and explore the possible mechanism.

OBJECTIVE

R9-SS-R9/miR-16 and cRGD-R9-SS-R9/miR-16 nanoparticles were successfully prepared. The nanoparticles, with a particle size below 150 nm, a dispersity index less than 0.1 and a potential of about 40 mV, showed a good serum stability. The polypeptide material had no obvious cytotoxicity. The miR-16/polypeptide nanoparticles could be efficiently absorbed by human ovarian cancer cells and were distributed in the cytoplasm. The nanoparticles significantly increased the intracellular expression level of miR-16 (P < 0.001) and decreased the expression of Bcl-2 and Chk-1 proteins in ovarian cancer cells, thus enabling miR-16 to promote apoptosis and enhance cisplatin sensitivity of the cells.

OBJECTIVE

We successfully prepared a miR-16/polypeptide nano-delivery system for targeted delivery of miR-16 to ovarian cancer cells for enhancing cisplatin sensitivity of the cancer cells.

LncRNA SLC16A1-AS1 Suppresses Cell Proliferation in Cervical Squamous Cell Carcinoma (CSCC) Through the miR-194/SOCS2 Axis

Background

SLC16A1-AS1 has been characterized as an oncogenic long non-coding (lncRNA) in breast cancer and bladder cancer, while its role in cervical squamous cell carcinoma (CSCC) is unknown.

Methods

CSCC and non-tumor tissue samples were collected from 60 female patients, and qPCR was performed to detect the expression of SLC16A1-AS1, miR-194 and SOCS2. Luciferase reporter assay was performed to detect the interaction between SLC16A1-AS1 and miR-194. Colony formation assay was used to detect cell proliferation.

Results

SLC16A1-AS1 was down-regulated in CSCC and correlated with poor survival. Overexpression of SLC16A1-AS1 could inhibit the proliferation of cervical cancer cells. In addition, SLC16A1-AS1 could sponge miR-194 and increase the expression levels of SOCS2, ultimately inhibiting the proliferation of cervical cancer cells.

Conclusion

SLC16A1-AS1 was downregulated in CSCC and suppressed cell proliferation in cervical squamous cell carcinoma (CSCC) through the miR-194/SOCS2 axis.

Vitamin D Signaling Pathways Confer the Susceptibility of Esophageal Squamous Cell Carcinoma in a Northern Chinese Population

Experimental studies have determined the chemopreventive effects of vitamin D against the esophageal squamous cell carcinoma (ESCC); however, results from the epidemiological studies are not yet well established. The current study aimed to evaluate the associations between plasma vitamin D levels and variants on vitamin D metabolic-related genes with the risks for ESCC. A hospital-based case-control study was performed. Five hundred eighty-two ESCC patients and 569 controls were recruited in a Northern Chinese population. Common variants on vitamin D metabolism-related genes CYP24A1, DHCR7, GC, CYP27B1, and vitamin D receptor (VDR) and the plasma 25(OH)D level were determined. The unconditional logistic regression method was applied to determine the associations between the variants and vitamin D level and ESCC. Higher plasma 25(OH)D was associated with a reduced risk for ESCC, especially for rs2296241, rs11568820, and rs4646536. The variants rs2296241 on CYP24A1 and rs11568820 on VDR are significantly associated with ESCC cancer. Vitamin D signaling pathways may participate in the ESCC development. Further studies with larger sample size are warranted to confirm the results. Intervention studies are needed to determine whether vitamin D supplementation may reduce the ESCC risk in the Chinese population.

miR-502 inhibits cell proliferation and tumor growth in hepatocellular carcinoma through suppressing phosphoinositide 3-kinase catalytic subunit gamma

MicroRNAs (miRNAs) play a key role in carcinogenesis and tumor progression in hepatocellular carcinoma (HCC). In the present study, we demonstrated that miR-502 significantly inhibits HCC cell proliferation in vitro and tumor growth in vivo. G1/S cell cycle arrest and apoptosis of HCC cells were induced by miR-502. Phosphoinositide 3-kinase catalytic subunit gamma (PIK3CG) was identified as a direct downstream target of miR-502 in HCC cells. Notably, overexpression of PIK3CG reversed the inhibitory effects of miR-502 in HCC cells. Our findings suggest that miR-502 functions as a tumor suppressor in HCC via inhibition of PI3KCG, supporting its utility as a promising therapeutic gene target for this tumor type.

The functional SNP rs3746804 in C20orf54 modifies susceptibility to esophageal squamous cell carcinoma

OBJECTIVE

The aim of the present study was to explore the association of the functional single-nucleotide polymorphism (SNP) rs3746804 in C20orf54 with the susceptibility to esophageal squamous cell carcinoma (ESCC).

METHODS

SNP rs3746804 in C20orf54 was detected by direct sequencing in 434 ESCC patients and 554 healthy controls from Shanxi and Henan Provinces in China, geographically a high incidence area for ESCC. The frequencies and distribution of TT, CT, and CC genotypes of SNP rs3746804 between those 2 cohorts were compared and its association with ESCC was assessed.

RESULTS

For SNP rs3746804 the genotype distribution of CT and CC in ESCC patients both significantly differed from those in healthy controls (p=0.002, 0.001, respectively), while the distribution of TT did not differ significantly between the groups (p=0.757). The ratio of T:C was high in healthy individuals and low in ESCC patients. Compared to genotype CC, both genotypes CT (odds ratio (OR)=0.63, 95% confidence interval (CI) 0.48l-0.826), and CT+TT (OR=0.654, 95% CI 0.507-0.844) were associated with significantly decreased risk for ESCC.

CONCLUSION

A close association exists between functional SNP rs3746804 in C20orf54 and susceptibility to ESCC.

Tumour-initiating capacity is independent of epithelial-mesenchymal transition status in breast cancer cell lines

Background:

Epithelial–mesenchymal transition (EMT) and cancer stem cells (CSCs) are considered to be crucial for cancer biology. The purpose of this study was to determine whether EMT directly led to the acquisition of tumour-initiating capacity in breast cancer cell lines.

Methods:

Epithelial–mesenchymal transition was induced in five breast cancer cell lines and one normal breast cell line by EMT-related cytokine stimulation. Mesenchymal–epithelial transition (MET) was induced by stably overexpressing miR-200c in three mesenchymal-like breast cancer cell lines. Molecular expression and cell function analysis were performed to evaluate the effect of EMT or MET on tumour-initiating capacity and other biological characteristics.

Results:

The induction of EMT did not enhance tumour-initiating capacity but, instead, conferred a CD44⁺/CD24^−/low phenotype as well as cell proliferation, migration, and resistance to doxorubicin and radiation on breast cancer cell lines. Furthermore, MET did not lead to inhibition or loss of the tumour-initiating capacity in mesenchymal-like breast cancer cell lines, but it markedly attenuated other malignant properties, including proliferation, invasion, and resistance to therapy.

Conclusions:

Epithelial–mesenchymal transition does not alter tumour-initiating capacity of breast cancer cells but some other biological characteristics. Therefore, EMT and tumour-initiating capacity may not be directly linked in breast cancer cell lines.

Functional single nucleotide polymorphism in C20orf54 modifies susceptibility to esophageal squamous cell carcinoma

The aim of this study was to explore the association of C20orf54 functional single nucleotide polymorphism (SNP) with the susceptibility to esophageal squamous cell carcinoma (ESCC) in a northern China population. The C20orf54 SNP was genotyped by direct sequencing in 240 cancer patients and 198 controls in northern China. The results showed that drinking status, family history of ESCC, and body mass index have great influence on the risk of developing ESCC. The overall genotype frequencies of C20orf54 in ESCC patients have a significant difference with healthy controls (χ(2)  = 8.06, P = 0.018). By using C/C genotype as the reference, the C/T genotype showed a significantly decreased risk to the development of ESCC. Thus, compared with the C/C genotype, smokers, drinkers with C/T genotype significantly decreased the risk of developing ESCC. A positive family history of ESCC with C/T and T/T genotype both increased the risk of developing ESCC. Body mass index between 18.5 and 24 with C/T genotype significantly decreased the risk of developing ESCC. The present study suggests that the C20orf54 functional SNP might be associated with a risk of development in ESCC.

Functional SNPs in human C20orf54 gene influence susceptibility to esophageal squamous cell carcinoma

OBJECTIVES

C20orf54, also known as a human riboflavin transporter 2 (RFT2), encodes an open reading frame protein RFT2 newly identified to play an important role in esophageal carcinogenesis by modulating riboflavin uptake. Missense cSNPs on exon 3,1172 C>A (T391M) and 1246A>G (I416V) have been suggested to modulate protein expression. The aim of present study was to explore the association of C20orf54 functional SNPs with susceptibility to esophageal squamous cell carcinoma (ESCC) in a northern Chinese population.

METHODS

240 patients with ESCC and 198 healthy individuals without overt cancer were chosen as our experimental subjects. Information about family address, sex, age, BMI, smoking and drinking habits and family history of cancer were collected. Blood samples were taken from all subjects and tumor tissues were freshly sampled from resected specimens. After DNA was extracted and amplified, the C20orf54 SNPs were sequenced by ABI 3730XL in BGI China. Frequencies were then calculated and associated with the collected suspicous risk factors.

RESULTS

Drinking status, a family history of ESCC, blood type and BMI were found to have great influence on the risk of developing ESCC. Overall genotype frequencies of the RFT2 SNP 1172 C>A (rs3746803) and 1246A>G (rs3746802) in ESCC patients are significantly different from that in healthy controls (x2=13.10, P=0.001 and x2=7.97, P=0.019, respectively). For RFT2 rs3746803, C/T+T/T genotype did not show a relationship with the risk of ESCC (the age and gender adjusted OR=0.66, 95% CI=0.41-1.05) when using C/C genotype as the reference. For RFT2 rs3746802, the A/G +G/G genotype demonstrated a significantly decreased risk to the development of ESCC (the age and sex adjusted OR=0.53, 95% CI=0.34-0.84) with A/A as the reference.

CONCLUSIONS

The present study suggests that the C20orf54 functional SNPs might be associated with a risk of ESCC development.

Ultrasound-facilitated formalin fixation of biological specimens

In a previous study, we showed that ultrasound can dramatically reduce the time required for tissue fixation in formalin. It generally is believed that ultrasound increases the speed of tissue fixation in two possible ways: 1) increasing the speed of penetration of fixative molecules into tissue samples and 2) increasing the speed of cross-linking reactions. We addressed here the second possible way by using protein solutions and cultured cells, which minimized the effects of the penetration factor. Proteins or cultured cells in solution were fixed with formalin with or without ultrasound irradiation. Fixed proteins and cell lysates then were separated by SDS-poly acrylamide gel electrophoresis and subjected to Western blotting to examine cross-linking formation in certain proteins. Unexpectedly, irradiation with ultrasound did not produce an observable difference in the rate of cross-linking in protein solutions. In similar experiments using cultured cells, however, we observed a significant reduction in recovery of certain proteins from cells fixed by formalin under the influence of ultrasound, which indicated that the ultrasound fixation procedure accelerated cross-linking formation within cells. Studies on protein and cell fixation without ultrasound showed that cross-linking formation was closely related to incubation temperature, which indicates that the heating function, which is inherently associated with ultrasound is another major factor in the ability of ultrasound to accelerate cross-linking.

Expression of recombinant rat Neurotrophin-3 in Chinese hamster ovary cells

The CHO cell line stably producing recombinant rat NT-3 was established. The insertion of rNT-3 cDNA into transferred cell gonome was analyzed with Southern blot. The expressed protein was identified by Dot ELISA (enzyme-linked immunosorbent assay) and Western blot. Western blot showed a clear specific band of about 14 ku for NT-3. The mean level of rNT-3 in four NT-3cDNA/CHO cell lines was about 2 100 ng/10(6) cells/48 h determined by EIA. The conditioned-medium (CM) of NT-3cDNA/CHO cells could promote the fiber outgrowth of the dissociated dorsal root ganglion of 8-day-old chick embryos, which shows a dose-response relationship. A half-maximal concentration of the biological activity (EC50) of the recombinant protein was approximately 16.7 ng/mL. The MoAb 3W3 of NT-3 could neutralize the biological activity of the rNT-3.

MRI findings of eosinophilic myelomeningoencephalitis due to Angiostrongylus cantonensis

AIM

To study the imaging characteristics of eosinophilic myelomeningoencephalitis due to Angiostrongylus cantonensis using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Seventeen MRI examinations of the brain and spinal cord in five patients with angiostrongyliasis cantonensis of the central nervous system were performed. The final diagnosis was based on typical clinical symptoms, results of blood and cerebrospinal fluid (CSF) tests, and the presence of nematode larvae in the CSF. The sequential MRI follow-up examinations were carried out at a different stage for every patient from 1 to 28 weeks after the onset of symptoms. The features of the lesions in the brain, spinal cord, meninges and nerve roots on MRI were studied, moreover, the development of the lesions was analysed on follow-up MRI.

RESULTS

Abnormalities were demonstrated on MRI in all five cases. They included three cases of meningoencephalitis, one case of encephalitis and one myelomeningitis. The locations and appearances of the lesions were as follows: (1) brain involvement in four cases (including cerebrum in four, cerebellum in two and brain stem in three), and spinal cord involvement in one case. These lesions were diffuse or scattered and appeared as similar or slightly reduced signal intensity on T1-weighted images (T1WI), high signal intensity on T2-weighted images (T2WI) and turbo fluid attenuated inversion recovery pulse sequence (FLAIR) images. After administration of gadolinium chelate (Gd-DTPA), multiple round or oval enhancing nodules, with diameters ranging from 3 to 10 mm, were seen on T1WI, a few lesions appeared as stick-shaped enhancement whose longest measurement was 14 mm. Diffuse or local oedema around the lesion could be seen. (2) Meningeal involvement in four cases, a case of ependymal involvement and a case of nerve root involvement were among them. These lesions appeared as linear or nodular enhancement of the leptomeninges and ependyma, as well as nerve root enhancement. (3) There was a mild ventricular enlargement in two cases. On follow-up MRI lesions were most severe from the 5th week to the 8th week and it took at least 4-8 weeks (1-2 months) for a lesion to resolve completely, the resolution of larger lesion needed more than 22 weeks.

CONCLUSION

Multiple enhancing nodules in the brain and linear enhancement in the leptomeninges were the main features; stick-shaped enhancement was the characteristic sign of the disease on Gd-DTPA enhanced-T1 weighted images.

Cloning and expression in Pichia pastoris of a genetically engineered single chain antibody against the rat transferrin receptor

The present investigation describes the construction of a genetically engineered single chain antibody (scFv) against the rat transferrin receptor (OX26), and demonstrates that this scFv antibody can be fully processed and expressed as a soluble secreted molecule in the methylotrophic yeast Pichia pastoris. Restriction endonuclease sites located at both 5'- and 3'-flanking regions of OX26 coding region in the prokaryote pOPE-OX26 vector were engineered to incorporate yeast compatible restriction endonuclease sites (i.e. EcoRI and SmaI or AvrII). The modified OX26 cDNA was subcloned into the Pichia expression vectors pPIC9 and pHIL-S1. An OX26 scFv high producer clone [GS115 His+ Mut+ (pPIC-OX26 SacI)] was isolated and used for large-scale production and characterization. Because the engineered scFv contains both a c-myc tag and a (His)5 tail, the OX26 scFv was purified to homogeneity by immobilized metal affinity chromatography. The identity of the OX26 scFv was confirmed by Western blot analyses with both anti c-myc and anti poly-His antibodies. Minor immunoreactive bands corresponding to hyperglycosylated and partially processed alpha-factor leader prosequence were also detected in the purified OX26 scFv, and these contaminants were markedly reduced when the expression of the OX26 scFv was performed in minimal methanol medium buffered with phosphate at pH = 7. The present investigation suggests that this expression system may be useful for the production of anti-receptor single chain antibodies that can be used as brain drug delivery vectors.

Substrate selectivity of Gluconobacter oxydans for production of 2,5-diketo-D-gluconic acid and synthesis of 2-keto-L-gulonic acid in a multienzyme system

Substrate selectivity of Gluconobacter oxydans (ATCC 9937) for 2,5-diketo-D-gluconic acid (2,5-DKG) production was investigated with glucose, gluconic acid, and gluconolactone in different concentrations using a resting-cell system. The results show that gluconic acid was utilized favorably by G. oxydans as substrate to produce 2,5-DKG. The strain was coupled with glucose dehydrogenase (GDH) and 2,5-DKG reductase for synthesis of 2-keto-L-gulonic acid (2-KLG), a direct precursor of L-ascorbic acid, from glucose. NADP and NADPH were regenerated between GDH and 2,5-DKG reductase. The mole yield of 2-KLG of this multienzyme system was 16.8%. There are three advantages for using the resting cells of G. oxydans to connect GDH with 2,5-DKG reductase for production of 2-KLG: gluconate produced by GDH may immediately be transformed into 2,5-DKG so that a series of problems generally caused by the accumulation of gluconate would be avoided; 2,5-DKG is supplied directly and continuously for 2,5-DKG reductase, so it is unnecessary to take special measures to deal with this unstable substrate as it was in Sonoyama's tandem fermentation process; and NADP(H) was regenerated within the system without any other components or systems.

Properties of acetylcholine receptor ion channels in the acutely dissociated neurons of the marginal division in the rat striatum

Cell-attached mode of patch clamp technique was employed to investigate the properties of acetylcholine (ACh)-induced ion channels in acutely dissociated neurons from the marginal division (MrD) of rat striatum. Two types of conductance states (25 pS and 60 pS) were recorded. The 25 pS channel (more than 80%) was the main type in the neurons of MrD and was described here. The amplitudes of inward currents increased with hyperpolorization and the reversing potential was about 0 mV. Both single short opening and long burst openings were observed in MrD neurons. Two-time constants of these two kinds of ion channels are 0.29 ms, 1.84 ms and 1.96 ms, 18.24 ms, respectively. Average close time can be fitted with two exponential functions, the two time constants are 1.7 ms and 54 ms. Probability of channel opening is about 0.012 and no voltage-dependence was found. The properties of reversing potential, voltage-independence and the form of agonist to the ion channels indicated that the recorded channel currents flow through AChR channels. The mAChR is involved in slow synaptic transmission and Ach can not induce the opening of mAChR ion channel. The binding site of ACh to AChR and the nAChR ion channel are the same protein, ACh can only activate nAChR ion channel directly. Therefore, the recorded ion channels in the present study are nAChR ion channels. The results suggest that nAChR ion channels exist in the neurons of MrD and the MrD probably is involved in learning and memory mechanism of the brain.

[Clinical and experimental study on treatment of Helicobacter pylori infected gastritis by xialian yiyou capsule]

OBJECTIVE

To observe the therapeutic effect of Xialian Yiyou Capsule (XLYYC) on helicobacter pylori (HP) infected gastritis to develop the serial Chinese classical recipe.

METHODS

HP infected patients were divided into two groups, 136 patients in the XLYYC group treated with XLYYC and 90 patients in the control group treated with Lizhu Dele Capsule, for 4 weeks as one therapeutic course, the clinical therapeutic effect was observed, and corresponding animal experiments were done.

RESULTS

Clinical effect of the XLYYC group was better than that of the control group in improving clinical symptoms, relieving inflammation of gastric mucosa and eliminating HP (P < 0.05, P < 0.01). Results of animal experiment showed that XLYYC was superior than the control significantly in anti-inflammation, analgesia, stomach emptying and curing gastric ulcer model (P < 0.05, P < 0.01). Without any adverse reaction has been found in acute toxicologic study.

CONCLUSION

The therapeutic effect of XLYYC in treating HP infected gastritis was definite and safe, non-toxic.

[Neural cluster structure with single component prediction in multiple variable systems for X-ray fluorescence spectrometry]

A neural cluster structure with single component prediction (NCSCP) was proposed for X-ray fluorescence spectrometry in a multivariable system. The neural cluster structure is built by the collection of a group of neurons which have close relationships among one another. In X-ray fluorescence analysis, the structure is constructed by choosing the elements in which there exist serious matrix effects, and deleting the components containing large noise. The predictability of the neural cluster structure was compared with that of the classical backward error propagation algorithm with single component prediction. The results show that the neural cluster structure is significantly superior to the classical algorithm in prediction accuracy, antidisturbance and the predictabilty to outliers.

[Changes of surface roughness and glossiness of the composite resins during polishing]

OBJECTIVE

To investigate the changes of surface roughness and glossiness of the composite resins during polishing.

METHODS

Nine conventional composite resins were evaluated. Composite specimens were polymerized on celluloid strip, so, smooth surfaces were obtained for each specimen, then the smooth surface of the specimens were sequentially polished with diamond polishing papers grits #240, #320, #400, #600, #800 and #1200. The roughness and glossiness of the central surface at 60 degrees reflex angle were measured.

RESULTS

The results showed that the values of roughness decreased steadily when specimens were polished with sequential polishing paper from coarse to fine one. A further polishing with grit #800, the values of roughness resumed to the pre-polishing values in all the composite specimen. The change of values of glossiness is very small within polishing with #240-#600. A further polishing with grit #800 and #1200, the values of glossiness increased jumpily. The values of glossiness of five composite resins reached or surpassed the level of pre-polishing.

CONCLUSION

This study indicates that fine surface would not be gained until the composite resins were polished with grit #800 and #1200 polishing paper.

[FPMULTI--a software for multi-layer composition and thickness analysis and its applications]

Main features of FPMULTI, a software for analyzing composition and thickness of multi-layer samples simultaneously using XRF, are briefly described in this paper. Based on fundamental parameter method, the software has the capability of determining multi-layer samples containing up to 10 layers and 25 elements. Calibration standards can be bulk or multi-layer of pure element or multi-element standards. Application examples for tin-plates, hot dip galvanized zinc-plates and 'fingerprint-resistant' plates were given. FPMULTI is used to predict the relationship between intensities of different X-ray lines and the thickness first and then to analyze those samples. When using only few calibration standards, the results from FPMULTI are much better than those from linear regression method, and this reflects the advantages of the fundamental parameter approach.

[Study on chemical components of Momordica charantia]

The paper deals with the study of chemical constituents of the unmatured fruits of Chinese traditional medicine Momordica charantia L. which is usually used as green-stuff. There are two parts of the extracts obtained by ethanol precipitation, and four compounds obtained from the further isolation. They are identified as Vincine, Mycose, Momordicoside A and Momordicoside B.

[Clinical evaluation for wear of composite resin in filling of molars]

To study the best evaluation method for wear of composite resins, 93 occlusal cavities of molars were restored with four kinds of light-cured composite resins, and three-year clinical research of wear analyses was performed using either direct evaluation method (USPHS) or indirect cast comparison (Leinfelder) method. The results suggested that the direct evaluation method for early wear of restorations would be less sensitive, but it remains the preferred system for the evaluation otherwise; the indirect method would be more reliable and sensitive, and numerical estimates of wear are more readily suitable for statistical analysis. The combination of direct and indirect methods will evaluate composite resin wear objectively and comprehensively.

[Clinical evaluation about restoration for cervical wedge-shaped defects of teeth using composite and dentin bonding]

100 cervical wedge-shaped defects of teeth with normal pulp from 19 patients were restored with light cure composite (durafill). For each patient, teeth of one side were experimental group, the other side were the control group, and left or right side was alternatively changed randomly. For the experimental group, the restorations of 49 teeth were adhered by Gluma dentin bonding. For the control group, the restorations of 51 teeth were adhered by Durafill bonding. The results of 2 years follow-up study with modified USPHS evaluation criterion indicate that curative effects, including retention and marginal sealing in the experimental group are much better than those in the control group.