[Clinical evaluation of platelet-rich plasma in the treatment of early and middle stage knee osteoarthritis under 3.0T MRI T2 mapping sequence]

Objective: To quantitatively evaluate the clinical effect of platelet-rich plasma(PRP) intra-articular injection for early and middle stage knee osteoarthritis(KOA) treatment by 3.0T MRI T2 mapping sequence. Methods: Clinical data of 26 patients with early or middle stage KOA who received treatment from April to December 2021 at Department of Orthopaedic Surgery,the Second Affiliated Hospital,Zhengzhou University were retrospectively analyzed. In total, 8 patients were male and 18 were female,with age of (66.4±12.0)years(range:51 to 94 years). Four patients were bilateral KOA and 22 patients were unilateral KOA.All patients received PRP intra-articular injection. Patients underwent 3.0T MRI T2 mapping sequence scanning pre-treatment,3-month-after and 6-month-after treatment respectively. Those were used to measure and compare T2 values of medial and lateral femoral articular surface and patellofemoral articular surface. Visual analogue scale(VAS) and Western Ontario and McMaster Osteoarthritis Index (WOMAC) score were recorded and evaluated. The results were analyzed using repeated measure ANOVA followed by Bonferroni multiple comparison test.The correlation between WOMAC scores and T2 values at pre-treatment and 6 months post-treatment was analyzed using Pearson correlation test. Results: After treatment, the patients' International Cartilage Regeneration＆Joint Preservation Society(ICRS) classification were partly improved(one case improved from grade Ⅲ to grade Ⅱ, one case improved from grade Ⅱ to grade Ⅰ),and all patients generally improved after treatment in clinical symptoms. Compared with pre-treatment,VAS and WOMAC scores of grade Ⅰ,Ⅱ,and Ⅲ of 6-month after treatment were declined significantly(all P<0.05).The T2 values of articular cartilage declined to varying degrees(the decrease in T2 values was about 2.06 ms in grade Ⅰ, 2.66 ms in grade Ⅱ, and 3.72 ms in grade Ⅲ).Three-month (VAS:4.8±1.3,WOMAC:21.5±4.0) and 6-month (VAS:4.2±1.4,WOMAC:17.2±2.9) after treatment, the VAS and WOMAC score were significantly higher than those before treatment (VAS:6.0±1.2, WOMAC:29.0±2.3) (F=48.846, F=346.746;both P<0.01). Multiple comparisons showed a statistically significant difference between pre-treatment and post-treatment VAS (P<0.01) and it also was significantly different between 3-month and 6-month post-treatment (P<0.01).At 3- and 6-month after treatment,WOMAC scores were significantly different from before treatment.And it also was significantly different between 3-month and 6-month post-treatment (P<0.01).There was a statistically significant improvement in T2 values of patellofemoral articular surface, medial and lateral femoral articular surface at pre-treatment((44.64±4.02)ms,(44.17±3.64)ms and(43.53±3.91)ms) and 3-month ((43.19±3.91)ms,(43.24±3.34)ms and (42.47±3.80)ms), 6-month ((41.49±3.64)ms,(41.83±3.15)ms and (41.10±3.42)ms) after treatment(F=148.845,F=73.657,F=86.268;all P<0.01).The results of the multiple comparisons showed a statistically significant difference in the T2 values of medial and lateral femoral articular surface and patellofemoral articular surface at each time point(all P<0.01).The Pearson correlation analysis suggested that the WOMAC score at pre-treatment was positively correlated with the medial condyle (r=0.856,P<0.01) and the patellofemoral joint surface T2 values (r=0.840,P<0.01);The WOMAC score at 6-month post-treatment was positively correlated with the medial condyle (r=0.731,P<0.01) and the patellofemoral joint surface T2 values (r=0.691,P<0.01). Conclusions: In the treatment of early and mid-stage KOA,MRI T2 mapping sequences are able to indicate the integrity of cartilage morphology and quantitatively evaluate cartilage repair. PRP has a good therapeutic effect on cartilage repair and reconstruction.

[Application of convolutional neural network to risk evaluation of positive circumferential resection margin of rectal cancer by magnetic resonance imaging]

Objective: To explore the feasibility of using faster regional convolutional neural network (Faster R-CNN) to evaluate the status of circumferential resection margin (CRM) of rectal cancer in the magnetic resonance imaging (MRI). Methods: This study was registered in the Chinese Clinical Trial Registry (ChiCTR-1800017410). Case inclusion criteria: (1) the positive area of CRM was located between the plane of the levator ani, anal canal and peritoneal reflection; (2) rectal malignancy was confirmed by electronic colonoscopy and histopathological examination; (3) positive CRM was confirmed by postoperative pathology or preoperative high-resolution MRI. Exclusion criteria: patients after neoadjuvant therapy, recurrent cancer after surgery, poor quality images, giant tumor with extensive necrosis and tissue degeneration, and rectal tissue construction changes in previous pelvic surgery. According to the above criteria, MRI plain scan images of 350 patients with rectal cancer and positive CRM in The Affiliated Hospital of Qingdao University from July 2016 to June 2019 were collected. The patients were classified by gender and tumor position, and randomly assigned to the training group (300 cases) and the validation group (50 cases) at a ratio of 6:1 by computer random number method. The CRM positive region was identified on the T2WI image using the LabelImg software. The identified training group images were used to iteratively train and optimize parameters of the Faster R-CNN model until the network converged to obtain the best deep learning model. The test set data were used to evaluate the recognition performance of the artificial intelligence platform. The selected indicators included accuracy, sensitivity, positive predictive value, receiver operating characteristic (ROC) curves, areas under the ROC curves (AUC), and the time taken to identify a single image. Results: The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the CRM status determined by the trained Faster R-CNN artificial intelligence approach were 0.884, 0.857, 0.898, 0.807, and 0.926, respectively; the AUC was 0.934 (95% CI: 91.3% to 95.4%). The Faster R-CNN model's automatic recognition time for a single image was 0.2 s. Conclusion: The artificial intelligence model based on Faster R-CNN for the identification and segmentation of CRM-positive MRI images of rectal cancer is established, which can complete the risk assessment of CRM-positive areas caused by in-situ tumor invasion and has the application value of preliminary screening.

Upregulation of serum miR-103 predicts unfavorable prognosis in patients with colorectal cancer

OBJECTIVE

Circulating microRNAs (miRNAs) have been reported as biomarkers for the early detection of colorectal cancer (CRC). We aimed at evaluating the diagnostic and prognostic value of serum miR-103 in CRC patients.

PATIENTS AND METHODS

Quantitative reverse-transcription PCR (qRT-PCR) was applied to measure the miR-103 levels in blood samples of 96 patients and 60 controls.

RESULTS

Our results demonstrated that serum miR-103 was overexpressed in CRC subjects and the receiver operating characteristic (ROC) curve analysis showed that serum miR-103 could differentiate CRC cases from controls with relatively high accuracy. In addition, serum miR-103 level was more frequently detected in CRC patients with positive lymph node metastasis, distant metastasis and advanced tumor stage. Moreover, serum miR-103 levels in 23 postoperative blood samples were lower than paired preoperative plasma specimens, and serum miR-103 levels were re-elevated in seven patients at recurrence. Furthermore, serum miR-103 was significantly correlated with worse clinical factors, as well as poorer recurrence-free survival or overall survival. Finally, multivariate analysis confirmed that serum miR-103 was an independent prognostic marker for CRC.

CONCLUSIONS

Taken together, serum miR-103 might be a promising biomarker for diagnosis and prognosis of CRC.

[Protective effect of Angelica sinensis polysaccharide against liver injury induced by D-galactose in aging mice and its mechanisms]

OBJECTIVE

To investigate the protective effect of Angelica sinensis polysaccharide (ASP) against liver injury induced by D-galactose in aging mice and its mechanisms.

METHODS

Male C57BL/6J were randomly divided into three groups with 10 mice in each group. In the D-galactose model group, the mice were subcutaneously injected with D-galactose (120 mg/kg) qd×42; in the ASP+D-galactose group, from the 8th day of the establishment of D-galactose model, the mice were subcutaneously injected with ASP (120 mg/kg) qd×35. In the normal control group, the mice were subcutaneously injected with isotonic saline of the same volume at the same time point. On the 2nd day after the injection was finished, the ocular blood was collected to prepare serum and measure the content of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBil). The liver tissue homogenate was prepared to measure the content of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), and advanced glycation end products (AGEs). A paraffin section of liver tissue was prepared; HE staining was performed to observe the pathomorphological changes of the liver, periodic acid-Schiff staining (PAS) was used to observe the changes in glycogen in the liver, and a transmission electron microscope was used to observe the hepatocyte ultrastructure.

RESULTS

The D-galactose model group had increased content of ALT, AST, and TBil, reduced activities of SOD and GSH-Px, an increased content of MDA, and severe liver injuries; the hepatocytes showed degenerative changes, the amount of glycogen in the liver decreased, and the accumulation of AGEs increased. The ASP+D-galactose group had reduced content of ALT, AST, and TBil, increased activities of SOD and GSH-Px, and reduced content of MDA and AGEs; the amount of glycogen in the liver increased, and liver injury and hepatocyte injury were alleviated.

CONCLUSION

ASP can antagonize the liver injury induced by D-galactose in aging mice, and its mechanism may be related to the inhibition of oxidative stress.

Reduction of magnetic damping and isotropic coercivity and increase of saturation magnetization in Rh-incorporated CoIr system

Replacing Ir with Rh in a CoIr system possessing negative uniaxial magnetocrystalline anisotropy (K _u ) substantially reduces its magnetic damping and coercivity by more than half while retaining its high negative K _u . Moreover, a higher saturation magnetization (M _s ) and more isotropic coercivity are achieved. Such material development makes it particularly suitable for use as the soft underlayer (SUL) of magnetic recording media for reducing noise, and as the oscillation layer of a spin-torque oscillator (STO) for achieving higher oscillation frequency, larger AC magnetic field and lower driving current, which can be readily integrated with the current recording head for microwave-assisted magnetic recording. Finally, we recommend a composite free layer by coupling CoIr with a spin polarizer (Co or Co/Cu/Co) for the enhancement of the spin-polarization rate and, therefore, the improvement of STO efficiency. These could pave the way for CoIr-based materials to be implemented in devices requiring a negative K_u with low damping and high 'softness', such as oscillators.

Phospholipases A-II (PLA2-II) induces acute pancreatitis through activation of the transcription factor NF-kappaB

OBJECTIVES

Acute pancreatitis (AP) is an inflammatory disease of the pancreas characterized by local inflammation. Secretory phospholipases A-II (sPLA2-II) have been implicated in triggering AP, but their exact role to evoke AP is largely unknown. NF-kB activation has previously been shown to induce acute pancreatitis. The aim of this study is to explore that PLA2-II triggers AP by activation of NF-kB and the expression of inducible inflammatory mediators.

MATERIALS AND METHODS

Acute pancreatitis in vivo was induced in Wistar rats by retrograde infusion of 4% sodium taurocholate (TAC) into the pancreatic duct. Then the Wistar rats were devided into 2 groups: (1) PLA2 II-specific siRNA was subsequently administrated subcapsularly after infusion of TAC. (2) One hour before the intraductal injection of TCA, the rats were treated with PDTC 100 mg/kg twice i.p. in 1 h interval. Induction of pancreatitis was confirmed by histopathology, NF-kB activity and expression in pancreas was detected by EMSA and immunohistochemistry. Inflammatory mediators such as the tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1beta, intercellular adhesion molecule-1 (ICAM-1), IL-6 and IL-8 in blood was detected by ELISA. The severity of the disease and the mortality were observed.

RESULTS

We demonstrated that TAC specifically induces pancreatitis, induces PLA2-II expression and activates NF-kappaB and proinflammatory cytokine synthesis in the pancreas of rats. sPLA2-II siRNA transfection blocked NF-kappaB activation and proinflammatory cytokine expression and relieved pancreatitis severity. PDTC treatment blocked NF-kappaB activation and proinflammatory cytokine expression. Pretreatment with PDTC or PLA2 II-specific siRNA transfection improved the survival of the rats.

CONCLUSIONS

These findings suggest that PLA2-II induces acute pancreatitis through activation of the transcription factor NF-kappaB. siRNA mediated gene knockdown of PLA2-II relieves pancreatitis severity at least partly mediated by the inhibition of NF-kappaB activation and proinflammatory cytokine synthesis.

Knockdown of PLA2G2A sensitizes gastric cancer cells to 5-FU in vitro

BACKGROUND-AIM

Elevated expression of the PLA2G2A phospholipase in gastric cancer (GC) is associated with improved patient survival. PLA2G2A is also an important regulator of proliferation, invasion and metastasis in GC. However, no relation about PLA2G2A and chemosensitivity in GC cells was reported. 5-Fluorouracil (5-FU) is widely used for treatment of advanced gastric cancer. However, it is common for such patients to develop resistance to 5-FU, and this drug resistance becomes a critical problem for chemotherapy. The mechanisms underlying this resistance are largely unknown. In the present study, we investigated whether PLA2G2A could confer 5-FU resistance or sensitise in GC cells in vitro.

MATERIALS AND METHODS

The 5-FU sensitivity of GC cell lines SGC-7901, MKN-45, RF-48, N87, AGS, MKN-28, RF-1, MGC-803 were determined by MTT assays. PLA2G2A levels were determined by western blot assays. The effects of 5-FU on PLA2G2A expression were determined in vitro. PLA2G2A was inhibited by silencing of the PLA2G2A using small interfering RNA in vitro. PLA2G2A was overexpressed by transfection of full-long PLA2G2A cDNA in vitro, and the effects were evaluated on 5-FU sensitivity.

RESULTS

The cell lines SGC-7901, MKN-45, RF-48 and N87 were sensitive, whereas AGS, MKN-28, RF-1 and MGC-803 were resistant to 5-FU. Significant correlation was observed between basal PLA2G2A and 5-FU sensitivity. Silencing of PLA2G2A increased 5-FU killing in 5-FU-treated cells, and overexpression of PLA2G2A decreased 5-FU killing in 5-FU-treated cells.

CONCLUSIONS

PLA2G2A was correlated with sensitivity to 5-FU. Silencing of PLA2G2A was sensitive to 5-FU treatment. Thus, PLA2G2A may be a useful therapeutic target for a subset of gastric cancers.

Fabrication of ultrahigh density metal-cell-metal crossbar memory devices with only two cycles of lithography and dry-etch procedures

A novel approach to the fabrication of metal-cell-metal trilayer memory devices was demonstrated by using only two cycles of lithography and dry-etch procedures. The fabricated ultrahigh density crossbar devices can be scaled down to ≤70 nm in half-pitch without alignment issues. Depending on the different dry-etch mechanisms in transferring high and low density nanopatterns, suitable dry-etch angles and methods are studied for the transfer of high density nanopatterns. Some novel process methods have also been developed to eliminate the sidewall and other conversion obstacles for obtaining high density of uniform metallic nanopatterns. With these methods, ultrahigh density trilayer crossbar devices (~2 × 10(10) bit cm(-2)-kilobit electronic memory), which are composed of built-in practical magnetoresistive nanocells, have been achieved. This scalable process that we have developed provides the relevant industries with a cheap means to commercially fabricate three-dimensional high density metal-cell-metal nanodevices.

Thymic stromal lymphopoietin: a promising therapeutic target for allergic diseases

Thymic stromal lymphopoietin (TSLP), an interleukin 7-like cytokine, can trigger dendritic cell (DC)-mediated T-helper type 2 (Th2) inflammatory responses. Recent evidence demonstrates that cytokines TSLP and OX40 (CD134)/OX40 ligand seem to be important players in the maintenance of Th2 memory pool in the pathogenesis of asthma. Accumulating data reveal that the pathogenic T cells involved in asthma are likely to be inflammatory Th2 cells. TSLP is involved in the development of asthma through crosstalk with nuclear factor NF-ĸB. Progression of skin fibrosis in atopic dermatitis occurs via TSLP/TSLP receptor. TSLP-mediated dermal inflammation aggravates experimental allergic asthma. Also, TSLP polymorphisms are associated with susceptibility to asthma, atopic dermatitis, and eczema herpeticum. These findings suggest a master switch of TSLP in the initiation of allergic and adaptive inflammation through innate pathways at the epithelial cell-DC interface. The TSLP pathway is therefore a promising target for immunotherapy of allergic diseases.

Selective blockade of NF-kappaB by novel mutated IkappaBalpha suppresses CD3/CD28-induced activation of memory CD4+ T cells in asthma

BACKGROUND

Nuclear factor kappaB (NF-kappaB) overactivation plays a crucial role in T-helper 2 (Th2)-biased allergic airway inflammation by increased activation and decreased apoptosis of CD4(+) T cells. We have shown that targeted NF-kappaB suppression in dendritic cells by adenoviral gene transfer of a novel mutated inhibitor of NF-kappaB (IkappaBalpha) (AdIkappaBalphaM) contributes to T-cell tolerance, but the immunosuppressive action of AdIkappaBalphaM on memory (CD45RO(+)) CD4(+) T cells remains enigmatic.

METHODS

CD45RO(+) T cells from Dermatophagoides farinaei-sensitized asthmatic patients, untransfected or transfected with AdIkappaBalphaM or AdLacZ (beta-galactosidase) for 24 h, were stimulated with anti-CD3 (1.0 microg/ml) plus anti-CD28 (0.5 microg/ml) monoclonal antibody for an additional 24 h. IkappaBalphaM transgene expression and NF-kappaB activation were detected by polymerase chain reaction (PCR), reverse transcription-PCR (RT-PCR), Western blot analysis, and electrophoretic mobility shift assay. Phenotype and apoptosis were measured by flow cytometry, annexin V binding, and terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling analyses. Cytokine production and cell proliferation were determined using enzyme-linked immunosorbent assay and [(3)H] thymidine incorporation.

RESULTS

A unique 801-bp IkappaBalphaM cDNA and a dose-dependent increase in IkappaBalphaM transgene expression were observed in AdIkappaBalphaM-transfected CD45RO(+) T cells. Significantly, AdIkappaBalphaM inhibited CD3/CD28-mediated NF-kappaB activation in CD45RO(+) T cells, leading to evident apoptosis, reduction of eotaxin, RANTES, Th1 [interferon (IFN)-gamma and interleukin (IL)-2], and Th2 (IL-4, IL-5, and IL-13 despite a slight decrease in IL-10) cytokines and secondary proliferative response. AdIkappaBalphaM also upregulated cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and downregulated CD69 besides no change in CD28.

CONCLUSION

IkappaBalphaM might be beneficial to augment memory CD4(+) T-cell tolerance through modulating B7-CD28/CTLA-4 co-stimulatory pathways and NF-kappaB-dependent cytokine profiles in allergic inflammatory diseases including asthma.

Endosperm-specific hypomethylation, and meiotic inheritance and variation of DNA methylation level and pattern in sorghum (Sorghum bicolor L.) inter-strain hybrids

Understanding dynamics and inheritance of DNA methylation represents important facets for elucidating epigenetic paradigms in plant development and evolution. Using four sets of sorghum (Sorghum bicolor L.) inter-strain hybrids and their inbred parents, the developmental stability and inheritance of cytosine methylation in two tissues, leaf and endosperm, by MSAP analysis were investigated. It was found that in all lines (inbred and hybrid) studied, endosperm exhibited a markedly reduced level of full methylation of the external cytosine or both cytosines at the CCGG sites relative to leaf, which caused a variable reduction in the estimated total methylation level in endosperm by 6.89-19.69% (11.47% on average). For both tissues, a great majority of cytosine methylation profiles transmitted to F1 hybrids, however, from 1.69 to 3.22% of the profiles showed altered patterns in hybrids. Both inherited and altered methylation profiles can be divided into distinct groups, and their frequencies are variable among the cross-combinations, and between the two tissues. The variations in methylation level and pattern detected in the hybrids were not caused by parental heterozygosity, and they could be either non-random or stochastic among hybrid individuals. Homology analysis of isolated bands that showed endosperm-specific hypomethylation or variation in hybrids indicated that diverse sequences were involved, including known-function cellular genes and mobile elements. RT-PCR analysis of six genes representing endosperm-specific hypomethylation in MSAP profiles indicated that all showed higher expression in endosperm than in leaf, suggesting involvement of methylation state in regulating tissue-specific or tissue-biased expression in sorghum. Analysis on leaf-RNA from 5-azacytidine-treated plants further corroborated this possibility.

Endosperm-specific hypomethylation, and meiotic inheritance and variation of DNA methylation level and pattern in sorghum (Sorghum bicolor L.) inter-strain hybrids

Understanding dynamics and inheritance of DNA methylation represents important facets for elucidating epigenetic paradigms in plant development and evolution. Using four sets of sorghum (Sorghum bicolor L.) inter-strain hybrids and their inbred parents, the developmental stability and inheritance of cytosine methylation in two tissues, leaf and endosperm, by MSAP analysis were investigated. It was found that in all lines (inbred and hybrid) studied, endosperm exhibited a markedly reduced level of full methylation of the external cytosine or both cytosines at the CCGG sites relative to leaf, which caused a variable reduction in the estimated total methylation level in endosperm by 6.89-19.69% (11.47% on average). For both tissues, a great majority of cytosine methylation profiles transmitted to F1 hybrids, however, from 1.69 to 3.22% of the profiles showed altered patterns in hybrids. Both inherited and altered methylation profiles can be divided into distinct groups, and their frequencies are variable among the cross-combinations, and between the two tissues. The variations in methylation level and pattern detected in the hybrids were not caused by parental heterozygosity, and they could be either non-random or stochastic among hybrid individuals. Homology analysis of isolated bands that showed endosperm-specific hypomethylation or variation in hybrids indicated that diverse sequences were involved, including known-function cellular genes and mobile elements. RT-PCR analysis of six genes representing endosperm-specific hypomethylation in MSAP profiles indicated that all showed higher expression in endosperm than in leaf, suggesting involvement of methylation state in regulating tissue-specific or tissue-biased expression in sorghum. Analysis on leaf-RNA from 5-azacytidine-treated plants further corroborated this possibility.

[Determination of solanesol in the extracts of tobacco leaves by high performance liquid chromatography]

A method for the determination of solanesol in the extracts of tobacco leaves by high performance liquid chromatography has been developed. The column used was Shim-pack CLC-SIL(5 microns, 5 mm i.d. x 150 mm) and the UV detector was set at 215 nm. The eluent was a mixture of n-hexane and isopropyl alcohol (98:2, V/V). As the results showed, the linear range was 1 microgram-10 micrograms(r = 0.9997), the average recovery of solanesol was 98.1% and the relative standard deviation was 1.9%. This method is fast, accurate and reproducible.

Model calculating annual mean atmospheric dispersion factor for coastal site of nuclear power plant

This paper describes an atmospheric dispersion field experiment performed on the coastal site of nuclear power plant in the east part of China during 1995 to 1996. The three-dimension joint frequency are obtained by hourly observation of wind and temperature on a 100 m high tower; the frequency of the "event day of land and sea breezes" are given by observation of surface wind and land and sea breezes; the diffusion parameters are got from measurements of turbulent and wind tunnel simulation test. A new model calculating the annual mean atmospheric dispersion factor for coastal site of nuclear power plant is developed and established. This model considers not only the effect from mixing release and mixed layer but also the effect from the internal boundary layer and variation of diffusion parameters due to the distance from coast. The comparison between results obtained by the new model and current model shows that the ratio of annual mean atmospheric dispersion factor gained by the new model and the current one is about 2.0.

[The determination of cantharidin in AIDI liquid injection by gas chromatography]

A method for the determination of cantharidin in AIDI liquid injection with gas chromatography is described. The cantharidin was extracted with dichloromethane and then determined by gas chromatography with OV-17 packed column and FID detector. Its distribution constant between dichloromethane and water was 480. The extraction recoveries of cantharidin were 99%-102%. The calibration curve was Y = -113 + 35,900X, r = 0.9999 and the detection limit was 0.02 mg/L in liquid injection. As the results showed, the method is simple, rapid, sensitive and precise for determining cantharidin in AIDI liquid injection.

[Determination of phenols in environmental water with bromination derivatization and gas chromatography]

A method for the determination of phenols in environmental water with bromination derivatization and gas chromatography is described. The phenols were transformed to bromophenols and then extracted with toluene and separated by the FFAP wide-bore capillary column and detected by electron capture detector (ECD). The results showed that the linear ranges were 0.06-80 micrograms/L for o-methylphenol and p-methylphenol, 0.03-40 micrograms/L for phenol and m-methylphenol. The detection limits for o-methylphenol, p-methylphenol, phenol and m-methylphenol were 0.03, 0.06, 0.01, 0.015 microgram/L respectively. The method is simple, rapid and reliable for determining phenols in environmental water.

[Epidemiological trend and its impact on malaria control programme in Shenzhen from 1950-1995]

Shenzhen has been developed as the first economic special zone in China. Two large scale outbreaks of vivax malaria have occurred in the history. Anopheles anthropophagus has been identified as the major vector. For the last 45 years, we have adopted an effective measure for malaria control based on the epidemiological characteristics in different period. As a result, the morbidity rate of malaria has been under control given the condition of social and economy development and the big increase of mobile population.

A field study of tritium migration in groundwater

A field study of tritium migration from an underground nuclear explosion was carried out for more than 7 years. A series of satellite wells was drilled around the explosion cavity, which is within a nuclear test site water-supply aquifer. Samples from various wells were analysed. In this way, variations in the tritium concentration of water from different wells were determined, and the extent of tritium migration during the 7 years after the detonation was examined. The maximum tritium concentration reached in water from various wells is just 52-times higher than the maximum permissible concentration for drinking water and decreased afterwards. According to the results obtained, the flow rate of groundwater was inferred to be about 91 m per year and the maximum contamination distance of water supplies by the tritium were < or = 2 km from the explosion cavity.

Methylflavonolamine protects aorta from atherosclerosis in cholesterol-fed rabbits

The effect of methylflavonolamine [4'-methyl-7-(2-hydroxy-3-isopropylamino-propoxy)-flavone hydrochloride, MFA], synthesized recently by the Shanghai Institute of Pharmaceutical Industry, on the development of atherosclerosis was studied in male New Zealand white rabbits fed cholesterol for 10 wk. MFA, 7 mg.kg-1 daily ip, did not significantly alter the serum total cholesterol, HDL, and triglyceride levels, but significantly lowered the aortic cholesterol and calcium contents. Atheromatous lesions covered 53.3 +/- 11.8% of the intimal surface of the aorta in the saline group and 11.3 +/- 2.3% in the MFA group (P < 0.01). We conclude that MFA suppresses cholesterol-induced atherosclerosis.

Transplantation of cultured premyelinating oligodendrocytes into normal and myelin-deficient rat brain

Cultures of oligodendroglial cells at various stages of maturation, from progenitors to maturing oligodendrocytes, were prepared from neonatal rat brain primary cultures and then were prelabeled in the culture dish with the fluorescent dye, fast blue (FB). Single cell suspensions were grafted into normal or myelin-deficient rat brains. The normal as well as the myelin-deficient in vivo environment allowed cell survival, migration, and differentiation. The FB+ cells expressed the oligodendroglial markers, glycerol phosphate dehydrogenase, galactocerebroside, and myelin basic protein. In the normal rat transplanted cells were identifiable at all times studied up to 24 weeks. Extensive migration of FB+ cells was observed in whole-brain sagittal sections. Our results show that the plasticity of oligodendroglia differentiation, extensively studied in vitro, can now be investigated in the normal and myelin-deficient in vivo environment.

[Effects of methylflavonolamine hydrochloride on contractility of isolated rabbit ileum]

Methylflavonolamine hydrochloride (MFA), verapamil (Ver), and trifluoperazine (Tri) inhibited the contractions induced by submaximal concentrations of acetylcholine (ACh) and serotonin (5-HT). IC50 values (mumol.L-1) were 33.2 +/- 0.7, 0.276 +/- 0.018, 3.83 +/- 0.23, and 15.31 +/- 0.10, 0.233 +/- 0.017, 2.33 +/- 0.20, respectively. MFA, Ver, and Tri inhibited the contractions induced by CaCl2 and pD'2 values were 4.3 +/- 0.3, 6.23 +/- 0.22, 4.99 +/- 0.24, respectively. MFA 3 mumol.L-1, Ver 0.03 mumol.L-1, and Tri 3 mumol.L-1 inhibited the contractions induced by ACh in Ca(2+)-free medium, while MFA 60 mumol.L-1, Tri 30 mumol.L-1, but not Ver 0.6 mumol.L-1, had pronounced inhibitions on extracellular calcium-dependent contractions induced by ACh. These results suggest that MFA has a calcium antagonistic effect and that MFA is similar to Tri, but not Ver, in mechanism.

Disruption of the Golgi apparatus by brefeldin A inhibits the cytotoxicity of ricin, modeccin, and Pseudomonas toxin

We have studied the cytotoxicity of ricin in cells treated with brefeldin A (BFA), which dramatically disrupts the structure of the Golgi apparatus causing Golgi content and membrane to redistribute to the ER. BFA inhibits the cytotoxicity of ricin in Chinese hamster ovary, normal rat kidney, and Vero cells and abolishes the enhancement of ricin cytotoxicity by NH4Cl, nigericin, swainsonine, and tunicamycin or by a mutation in endosomal acidification. BFA protects cells from the cytotoxicities of modeccin and Pseudomonas toxin, but has no effect on the intoxication by diphtheria toxin. Pretreatment of BFA does not protect cells from ricin treatment in the absence of BFA. Our results suggest that ricin, modeccin, and Pseudomonas toxin share a common pathway of intracellular transport from endosomes to the Golgi region where they are released into the cytosol. In contrast, the lack of protection of Vero cells from diphtheria toxin by BFA indicates that diphtheria toxin is released from acidified endosomes without involving the Golgi region.

Increased cytotoxicity of ricin in a putative Golgi-defective mutant of Chinese hamster ovary cell

We have studied the cytotoxicity of ricin in a monensin-resistant mutant (MonR-31) of Chinese hamster ovary (CHO) cell line which is presumably altered in Golgi functions/structures. The cytotoxicity of ricin was increased in MonR-31 mutant cells compared with that in its parental CHO cells. In wild-type CHO cells, the cytotoxicity of ricin was enhanced by HN4Cl, bafilomycin A1, or nigericin. The enhancement of ricin cytotoxicity by these compounds was greatly reduced in MonR-31 mutant cells. Brefeldin A (BFA), which disrupts the structure of the Golgi apparatus, inhibits the cytotoxicity of ricin in both CHO and MonR-31 cells. We have also examined the effects of glycosylation inhibitors and the removal of high mannose oligosaccharide chains in ricin on the ricin hypersensitivity in MonR-31 cells. The hypersensitivity of MonR-31 cells to ricin is apparently not due to any difference in glycosylation between CHO and MonR-31 cells or in the processing of oligosaccharides on ricin by the target cells. Nigericin at low concentration (10 nM), which has no effect on the cytotoxicity of diphtheria toxin, enhances the ricin cytotoxicity, but inhibits the modeccin cytotoxicity. Our results suggest that important step(s) in the intoxication process of CHO cells by ricin and modeccin take place in the Golgi region.

Developmental regulation of myelin-associated genes in the normal and the myelin deficient mutant rat

Oligodendrocyte development and myelinogenesis, both in vivo and in vitro, are characterized by the sequential and coordinate expression of markers which participate in the differentiation of oligodendrocytes as a prerequisite for myelination. The myelin deficient (md) rat shows greatly reduced mRNA expression for several oligodendrocyte markers: glycerol phosphate dehydrogenase (GPDH), myelin basic protein (MBP) and proteolipid protein (PLP). Brain GPDH mRNA levels are initially equivalent in md and unaffected littermates, but the mutant rats fail to display the normal developmental increase in gene expression. Immunostaining of brain tissue sections also reveals decreased expression of these oligodendrocyte markers. The number of oligodendrocytes containing GPDH-like immunoreactivity is reduced in mutant rats, and in general these cells appear morphologically less complex with shorter processes. However, the intensity of staining in many oligodendrocytes appears equivalent to that observed in unaffected rats. Expression of the neuronal marker, glutamic acid decarboxylase, and the astrocyte markers, glutamine synthetase and glial fibrillary acidic protein, are largely unaffected at either the mRNA or protein level. Mixed glial cultures prepared from the brains of neonatal male md rats possess fewer oligodendrocytes compared to cultures derived from unaffected littermates, and the temporal sequence of marker development is delayed. Although an abnormality in the PLP gene is suspected in the md rat, these findings document profound deficits in many oligodendrocyte gene products.

Short-term multidrug therapy in multibacillary leprosy--review of 80 cases in two provinces of China (1983-1988)

Thirty-three active multibacillary patients from nine counties of Weifang Prefecture, Shandong Province, and 47 active cases from Menla County, Yunnan Province, People's Republic of China, were treated with 24 and 27 months of multidrug therapy (MDT), respectively, in 1983. Clinical assessments, smears, and histopathologic examinations were carried out independently by study teams from the Institutes of Dermatology of these two provinces. Reexaminations at 12-14 months and at termination of therapy showed marked improvement, and there was continued improvement at 12-18 and 33 months on follow up. Conversion of the bacterial index to negativity was 0/33, 5/47 for the patients from Shandong and Yunnan provinces, respectively, at the end of MDT and 2/33 at 12 months' and 17/47 at 18 months' follow up, which increased to 21/33 and 26/44 at 33 months' follow up. Regression of specific infiltration was about 21%-100% after 24-27 months of MDT; further regression to 95%-100% occurred at 33 months' follow up.

[Cost-effectiveness analysis of two-dimensional/Doppler echocardiography, cardiac catheterization and angiography in the diagnosis of congenital heart disease]

To compare the costs and effectivenesses of 2-dimensional/Doppler echocardiography (2D/DE), cardiac catheterization (CC) and angiography (CA) in the evaluation of cardiac anatomy in patients with congenital heart disease, these three kinds of examinations were performed in 100 patients before operation. The 100 patients had 120 separate cardiovascular abnormalities, of which 100 (83.3%) were prospectively identified by 2D/DE. The sensitivity and specificity of 2D/DE were: ASD, 87.9% and 100%; VSD, 97.9% and 96.1%; PDA, 86.7% and 98.2%, Tetralogy of Fallot, 6 of 6 patients; the overall sensitivity and specificity of the less common defects, 31.6% and 95.8%. Ninety-seven (80.8%) were prospectively identified by catheterization. The sensitivity and specificity of catheterization were: ASD, 87.9% and 100.0%; VSD, 80.9% and 94.6%; PDA 93.3% and 96.6%; Tetralogy of Fallot, 6 of 6 patients, the less common defects, 52.6% and 95.5%. Forty-five (81.8%) were prospectively identified by angiography in 55 patients. The sensitivity and specificity of angiography: ASD, 5 of 7 patients, VSD, 88.0% and 94.3%; PDA, 2 of 2 patients; Tetralogy of Fallot, 5 of 5 patients; the less common defects, 68.8% and 100.0%. The economic evaluations were performed. The costs of the depreciation (including equipments and houses), hospital bed, water and electricity, management and staffs' wage were: 2D/DE, RMB 46.09 per patient; catheterization, RMB 314.17 per patient; angiography, RMB 314.17. The ratios of cost to outcome (cost per correct diagnosis) of 2D/DE, CC and CA were: 55.33, 388.82 and 384.07 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Methylflavonolamine hydrochloride inhibits contractions induced by noradrenaline, calcium and potassium in rabbit isolated aortic strips

1. The effects of methylflavonolamine hydrochloride (4'-methyl-7-(2-hydroxy-3-isopropylamino-propoxy)-flavone hydrochloride, MFA) were investigated and compared with verapamil and papaverine on rabbit isolated aortic strips, which were contracted by noradrenaline, calcium and potassium. 2. Pre-incubation for 25 min with either MFA (0.03 to 0.2 mM) or papaverine (0.03 to 0.2 mM) induced non-parallel and concentration-dependent rightward displacements of the curves to noradrenaline (0.00001 to 0.1 mM) with the maximal response depressed. The calculated pD2' values (mean +/- s.d.) were 3.89 +/- 0.15 for MFA and 3.93 +/- 0.05 for papaverine, respectively. Verapamil (0.03 to 0.2 mM) inhibited the contraction induced by noradrenaline in a competitive manner with a pA2 value of 5.91 +/- 0.83. 3. In depolarized aortic strips of the rabbit, prior exposure to MFA (0.03 to 0.3 mM) and papaverine (0.03 to 0.2 mM) shifted the cumulative curves to Ca2+ (0.003 to 100 mM) parallel to the right with the maximal responses depressed, pD'2 values being 3.88 +/- 0.05 and 3.89 +/- 0.13, respectively. Verapamil produced comparable inhibition of the contraction at much lower concentrations (30 to 300 nM). 4. MFA (0.03 and 0.1 mM) inhibited the contraction elicited by graded depolarization at a constant Ca2+ concentration with a pD'2 value of 4.09 +/- 0.07. 5. The present results show that MFA has some actions consistent with a calcium antagonist. It resembles papaverine more closely than verapamil.

[O6-methyldeoxyguanosine in DNA of the adjacent epithelium in human esophageal cancer in Linxian County]

Radioimmunoassay of monoclonal antibodies against O6-methyldeoxyguanosine (O6-MedG) was used to detect the presence of these DNA adducts in the human esophageal epithelium. The analysis comprised 48 adjacent epithelial specimens of the esophageal and cardiac cancer resected in Linxian County and 30 specimens of the fetal esophageal epithelium and 4 of the normal esophageal epithelium from autopsy as collected from the hospital in Beijing. The results show that O6-MedG was detected in all the specimens from the esophageal and cardiac cancer patients. In 7 samples in the adjacent epithelium of esophageal cancer, the level of O6-MedG ranged from 0.5 to 1.0 pmol/mgDNA. 19 showed higher levels up to 37.4 pmol/mgDNA with a mean of 4.72 +/- 6.08 pmol/mgDNA. 5 samples of gastric mucosa showed the level of O6-MedG ranging 0.3-1.0 pmol/mgDNA and the remaining 6 showed a higher level of 1.2-13.4 pmol/mgDNA. The mean was 3.31 +/- 3.97. In all the 11 patients, O6-MedG was detected in the para-cancerous gastric mucosa of the cardiac cancer. 4 normal autopsied esophageal epithelial samples were too low for detection. Samples from the fetal esophageal epithelium showed lower level of O6-MedG, the mean was 0.4 +/- 0.57 pmol/mgDNA. The results mentioned above give us the new evidence that the effect of N-nitrosamines is most likely a causative factor in the carcinogenesis of human esophageal cancer.

Relevance of N-nitrosamines to esophageal cancer in China

Studies on the relevance of the N-nitrosamines to esophageal cancer in China are reviewed. Esophageal cancer is a complex and multifactorial problem. Although a causal association between nitrosamines exposure and esophageal cancer in China has not yet been rigorously established, exposure of Lin-Xian subjects to nitrosamines either directly or as a result of their in vivo formation has been detected in our study. Several N-nitrosamines (NDMA, NDEA, NMBzA, NPyr, NPip, and NSAR) in gastric juice collected from Lin-Xian inhabitants have been detected. A correlation was found between the lesions of esophageal epithelium and the amount of nitrosamines present. In addition, the amounts of N-nitrosamino acids (N-nitrosoproline, N-nitrosothiazolidine 4-carboxylic acid, NSAR, and nitrates) excreted in 24-hr urine of subjects in Lin-Xian were significantly higher than those in Fan-Xian, indicating a higher exposure to N-nitroso compound and their precursors of the inhabitants in the high-risk area. The effect of nitrosamines on human esophagus has been investigated at the cellular levels. The amounts of O6-MedG in DNA of esophageal or stomach mucosa of patients from Lin-Xian were higher than that from Europe (Lyon and Essen). The presence of O6-MedG in the human fetal esophagus cultured with NMBzA was also detected. These findings indicate that the elevated levels of O6-MedG in esophageal DNA could be the result of a recent exposure to N-nitroso compounds or a genetically determined reduced cellular capacity for repair of O6-MedG from DNA. The hyperplasia was induced in the esophagus of human fetus that cultured with NMBzA for 2 weeks to 2 months. The intervention studies of esophageal cancer in Lin-Xian have been pursued. Intake of moderate doses of ascorbic acids by Lin-Xian subjects effectively reduced the urinary levels of N-nitrosamino acids to those found in un-dosed subjects in the low-risk area. If N-nitroso compounds are formed in vivo and are among the causative factors of esophageal cancer in Lin-Xian, ascorbic acid appears to be effective in lowering the body burden of these carcinogenic compounds. Thus, the plan of chemoprevention is carried out in Lin-Xian.