[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.

[Hesperetin inhibits PM(2.5)-induced apoptosis in H9c2 cells by attenuating oxidative stress and mitochondrial damage].

Objective: To investigate the effects of hesperetin on fine particulate matter (PM(2.5)) induced apoptosis in H9c2 cells and related mechanisms. Methods: H9c2 cells were divided into 4 groups: control group (cells were cultured without intervention), PM(2.5) group (cells were treated with 800 µg/ml PM(2.5)), hesperetin group (H group, cells were treated by 40 µmol/L hesperetin for 1 h at 37 ℃), and hesperetin+PM(2.5) group (H+PM(2.5) group, cells were pretreated with hesperetin before PM(2.5) treatment). Cells were cultured for corresponding interval. Apoptotic cells were detected by Annexin Ⅴ-FITC/PI apoptosis detection kit and Hoechst staining. The intracellular reactive oxygen species (ROS) levels were measured by DCFH-DA Fluorescence Probe and mitochondrial membrane potential (MMP) was detected with JC-1 staining, respectively in these groups. Apoptotic related protein and phosphorylated MAPK expression levels were determined by Western blot. Results: (1) Flow cytometry results showed that the apoptosis rate of PM(2.5) group ((48.94±3.20)%) was significantly higher than that of control group ((8.13±1.40)%, P<0.01), which was significantly reduced in H+PM(2.5) group ((34.80±2.21)%) (P=0.003 2 vs. PM(2.5) group, P<0.01 vs. control group). The number of Hoechst 33258 positive apoptotic cells was distinctly less in H+PM(2.5) group than in PM(2.5) group. (2) The ROS levels was significantly higher in PM(2.5) group ((49.69±5.05)%) than in control group (10.57±1.33)%, P<0.01), which was significantly reduced in H+PM(2.5) group ((35.08±3.90)%) (P=0.000 2 vs. PM(2.5) group, P<0.01 vs. control group). (3) Green fluorescence indicating the JC-1 monomer form, which represented MMP loss of H9c2 cells, was significantly higher in PM(2.5) group ((20.28±4.69)%) than in control group ((10.50±2.72)%, P<0.01), which was significantly decreased in H+PM(2.5) group ((13.41±2.89)%) (P<0.01 vs. PM(2.5) group, P=0.029 4 vs. control group). (4) The expression levels of Bcl-2 protein of H9c2 cells was lower in PM(2.5) group ((76.94±4.52)%) than in control group (100%, P=0.000 9), which was significantly upregulated in H+PM(2.5) group ((92.95±6.82)%) (P=0.027 5 vs. PM(2.5) group, P=0.15 vs. control group). The expression levels of cleaved caspase-3 protein of H9c2 cells was significantly higher in PM(2).5 group ((243.98±17.94)%) than in control group (100%, P=0.000 2), which was significantly downregulated in H+PM(2.5) group ((200.45±4.31)%) (P=0.015 vs. PM(2.5) group, P<0.01 vs. control group). (5) The expression levels of phosphorylated p38 MAPK protein of H9c2 cells was higher in PM(2.5) group ((118.90±4.78)%) than in control group(100%, P=0.002 7), which could be significantly downregulated in H+PM(2.5) group ((103.30±1.27)%) (P=0.01 vs. PM(2.5) group, P=0.05 vs. control group). The expression levels of phosphorylated ERK protein of H9c2 cells was higher in PM(2.5) group ((163.50±4.98)%) than in control group (100%, P<0.01), which was significantly downregulated in H+PM(2.5) group ((139.10±2.72)%) (P=0.001 6 vs. PM(2.5) group, P<0.01 vs. control group). Conclusions: Hesperetin protects H9c2 cells from PM(2.5) stimulation through reducing oxidative stress and protecting mitochondrial function, regulating the expression of apoptotic associated proteins as well as MAPK signal pathway, thus inhibiting H9c2 cells apoptosis.

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 Ku with low damping and high 'softness', such as oscillators.

[Strategy of the diagnosis and treatment for hydrocephalus associated with acoustic neuroma].

OBJECTIVE: To describe and analyze the strategy of the diagnosis and treatment for acoustic neuroma associated with hydrocephalus. METHODS: A retrospective review was performed in 29 patients with hydrocephalus associated with acoustic neuroma form Apr. 2004 to Apr. 2015. The patients' clinical information, the types of the hydrocephalus, the treatment and the prognosis of the hydrocephalus were recorded. RESULTS: There were 20 patients with obstructive hydrocephalus and 9 patients with communicating hydrocephalus preoperatively. Among the 29 cases, 3 patients had ventriculoperitoneal shunts, 5 patients had external ventricular drains, the remaining 21 patients had no further managements for hydrocephalus; after removing the acoustic neuroma, the hydrocephalus improved in 10 cases, the ventricle unchanged in 10 cases among the obstructive hydrocephalus group, the ventricle unchanged in all 9 cases among the communicating hydrocephalus group. Nineteen cases were diagnosed with communicating hydrocephalus and 10 cases with obstructive hydrocephalus postoperatively. CONCLUSIONS: Among the patients of acoustic neuroma associated with hydrocephalus, communicating hydrocephalus is more common than obstructive hydrocephalus. The optimal management of acoustic neuroma associated with hydrocephalus is complete removal of the tumor, with treatment only for patients with persistent hydrocephalus.

[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.

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.

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.

[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.

[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.

[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.

[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.

Hepatitis C virus RNA detection in serum and peripheral blood mononuclear cells of patients with hepatitis C.

AIM: To investigate the existence and clinical significance of hepatitis C virus (HCV) RNA in the serum and peripheral blood mononuclear cells (PBMC) of patients with hepatitis C. METHODS: HCV RNA was detected by nested polymerase chain reaction (Nested PCR) in serum and in PBMC of 46 patients with acute hepatitis C (AHC) and in 42 patients with chronic hepatitis C (CHC). RESULTS: The positive rate of HCV RNA in PBMC of patients with CHC was markedly higher than that of patients with AHC (P < 0.01). The positive rates of HCV RNA in serum of patients with AHC and CHC and in PBMC of patients with CHC were significantly higher than those of anti-HCV positive patients with normal alanine aminotransferase (ALT) levels (P < 0.01). HCV RNA was negative in the serum of two patients, but could be detected in PBMC. In 12 patients, anti HCV was negative while HCV RNA was positive in serum. CONCLUSION: (1) detection of serum HCV RNA by nested PCR might be helpful in the early diagnosis of anti-HCV negative hepatitis C; (2) liver damage in patients with hepatitis C might be correlated with HCV-viremia; (3) infection of PBMC by HCV might play an important role in chronic liver damage in patients with HCV and in the chronicity of its clinical course; and (4) PBMC might be considered as a "reservoir" for HCV.