[Epidemiological characteristics of reinfection of 2019-nCoV and influencing factors in Ningbo]

Objective: To analyze the epidemiological characteristics of reinfection of 2019-nCoV and influencing factors, and provide evidence for effective prevention and control of COVID-19 epidemic. Methods: The incidence data of COVID-19 in Ningbo from January 1, 2020 to November 30, 2022 were collected from the infectious disease surveillance system of Chinese information system for disease control and prevention. The incidence of reinfection of 2019-nCoV was investigated by using questionnaire. logistic regression analysis was used to analyze the influences of gender, age, time interval from the first infection, history of underlying disease, 2019-nCoV vaccination dose and disease severity on the reinfection. Results: A total of 897 previous 2019-nCoV infection cases were investigated, of which 115 experienced the reinfection of 2019-nCoV, the reinfection rate was 12.82%. The interval between the two infections M(Q1, Q3) was 1 052 (504, 1 056) days. Univariate analysis showed that age, 2019-nCoV vaccination dose, history of underlying disease, type of 2019-nCoV variant causing the first infection, time interval from the first infection and severity of the first infection were associated with the reinfection rate (all P<0.05). Multivariate logistic regression analysis showed that the risk for reinfection in age group 30- years was higher than that in age group ≥60 years (OR=2.10, 95%CI: 1.11-3.97). No reinfection occurred in those with time interval from the first infection of <6 months, and the risk for reinfection was higher in those with the time interval of ≥12 months than in those with the time interval of 6- months (OR=6.68, 95%CI: 3.46-12.90). The risk for reinfection was higher in the common or mild cases than in the asymptomatic cases (OR=2.64, 95%CI: 1.18-5.88; OR=2.79, 95%CI: 1.27-6.11). Conclusion: The time interval from the first infection was an important influencing factor for the reinfection of 2019-nCoV, and the probability of the reinfection within 6 months was low.

Fasting produces antidepressant-like effects via activating mammalian target of rapamycin complex 1 signaling pathway in ovariectomized mice

Recent studies have shown that a 9-hour fast in mice reduces the amount of time spent immobile in the forced swimming test. However, whether 9-hour fasting has therapeutic effects in female mice with depressive symptoms has not been established. Therefore, in this study, we simulated perimenopausal depression via an ovariectomy in mice, and subjected them to a single 9-hour fasting 7 days later. We found that the ovariectomy increased the time spent immobile in the forced swimming test, inhibited expression of the mammalian target of rapamycin complex 1 signaling pathway in the hippocampus and prefrontal cortex, and decreased the density of dendritic spines in the hippocampus. The 9-hour acute fasting alleviated the above-mentioned phenomena. Furthermore, all of the antidepressant-like effects of 9-hour fasting were reversed by an inhibitor of the mammalian target of rapamycin complex 1. Electrophysiology data showed a remarkable increase in long-term potentiation in the hippocampal CA1 of the ovariectomized mice subjected to fasting compared with the findings in the ovariectomized mice not subjected to fasting. These findings show that the antidepressant-like effects of 9-hour fasting may be related to the activation of the mammalian target of the rapamycin complex 1 signaling pathway and synaptic plasticity in the mammalian hippocampus. Thus, fasting may be a potential treatment for depression.

Current Evidence and Future Directions of Berberine Intervention in Depression

A major type of serious mood disorder, depression is currently a widespread and easily overlooked psychological illness. With the low side effects of natural products in the treatment of diseases becoming the pursuit of new antidepressants, natural Chinese medicine products have been paid more and more attention for their unique efficacy in improving depression. In a view from the current study, the positive antidepressant effects of berberine are encouraging. There is a lot of work that needs to be done to accurately elucidate the efficacy and mechanism of berberine in depression. In this review, the relevant literature reports on the treatment of depression and anxiety by berberine are updated, and the potential pharmacological mechanism of berberine in relieving depression has also been discussed.

[Analysis of clinical features of cervical precancerous lesions in postmenopausal women]

Objective: To analyze the characteristics of high-grade squamous intraepithelial lesion (HSIL) diagnosed by cervical tissue sampling in postmenopausal women. Methods: A retrospective study was performed on 2 013 patients with HSIL diagnosed by cervical tissue sampling under colposcopy and treated by cervical conization at the First Affiliated Hospital of Zhengzhou University from June 2017 to November 2018, to compare the difference of patients' clinical features, HPV test, liquid-based thin-layer cytology (TCT), performance of colposcopy and biopsy pathology, pathology after cervical conization between 439 postmenopausal patients and 1 574 pre-menopausal patients. Results: (1) Clinical features: the proportion of contact bleeding showed no significant difference between postmenopausal patients and pre-menopausal patients [4.3% (19/439) vs 6.4% (101/1 574); χ²=2.672, P=0.102]. Among the patients with contact bleeding, the proportion of cervical cancer after cervical cone resection was significantly higher in postmenopausal patients compared with pre-menopausal patients [10/19 vs 22.8% (23/101); χ²=7.157, P=0.007]. Among the patients found by routine screening, the proportion of cervical cancer after cervical cone resection was significantly higher in postmenopausal patients compared with pre-menopausal patients [9.0% (38/420) vs 4.3% (63/1 473); χ²=14.726, P<0.01]. The proportion of smooth cervix was higher in postmenopausal patients compared with pre-menopausal patients [63.6% (279/439) vs 35.5% (558/1 574); χ²=111.601, P<0.01]. (2) High-risk HPV infection: there was no significant difference in the high-risk HPV positive rate between the postmenopausal group and the pre-menopausal group [92.0% (404/439) vs 94.4% (1 486/1 574); χ²=3.394, P=0.065]; the HPV 16 infection was the most common type, but there was no significant difference in the HPV 16 infection rate between the two groups [65.8% (289/439) vs 68.0% (1 070/1 574); χ²=0.722, P=0.395]. (3) TCT test: TCT test results included negative for intraepithelial lesion and malignancy (NILM), atypical squamous cell of undetermined signification (ASCUS), atypical squamous cells cannot exclude high-grade lesion (ASC-H), low grade squamous intraepithelial lesion (LSIL), HSIL, compared with the different results of TCT examination, there were not statistically significant difference between postmenopausal and pre-menopausal patients (all P>0.05). (4) The performance of colposcopy: the proportion of insufficient colposcopy and the proportion of cervical type Ⅲ conversion area were higher in postmenopausal patients compared with pre-menopausal patients [87.5% (384/439) vs 32.5% (511/1 574), P<0.01; 80.0% (351/439) vs 21.9% (344/1 574), P<0.01]. The proportion and positive rate of endocervical curettage (ECC) in postmenopausal patients were higher than those in pre-menopausal patients [35.3% (155/439) vs 20.4% (322/1 574), P<0.01; 67.7% (105/155) vs 53.1% (171/322), P=0.003]. The proportion of lesions involving the vaginal wall was higher in postmenopausal patients compared with pre-menopausal patients [5.9% (26/439) vs 1.0% (16/1 574); χ²=40.443, P<0.01]. There was a positive correlation between vaginal wall lesions and cervical lesions in postmenopausal patients (r=0.660, P<0.01). (5) Postoperative pathology: the positive rate of margin and the proportion of pathological escalation after cervical conization were significantly higher in postmenopausal patients compared with pre-menopausal patients [14.6% (64/439) vs 4.8% (75/1 574), 10.9% (48/439) vs 5.5% (86/1 574); P<0.01]. Conclusions: Colposcopy in postmenopausal women is often inadequate, and the cervix is mostly type Ⅲ transformation zone. The lesion in postmenopausal women is more likely to involve the cervical canal and vaginal wall. Clinical attention should be paid to cervical tube curettage and comprehensive examination of the vaginal wall. The high rate of positive margins and a high proportion of pathological upgrading after cervical conization in postmenopausal patients requires further active intervention.

[Grading evaluation of operative complications and analysis of related risk factors in patients with stage Ⅰ endometrial cancer treated by robotic-assisted and traditional laparoscopic surgery]

Objective: To investigate the surgical complications in the treatment of stage Ⅰ endometrial cancer by robotic-assisted laparoscopy, the risk degree of Clavein-Dindo complications and the main risk factors affecting the occurrence of surgical complications. Methods: A retrospective case-control study was conducted in the First Affiliated Hospital of Zhengzhou University from October 2014 to June 2019. The patients were divided into robotic-assisted laparoscopy group and traditional laparoscopy group according to the operation mode, including 131 cases in robot group and 290 cases in traditional laparoscopy group. To compare the complications during and after operation and the risk degree of complications between the two groups by Clavein-Dindo classification standard, the age, body mass index (BMI), comorbidities, past history of pelvic surgery, American Society of Anesthesiologists (ASA) grade, preoperative anemia, number of pelvic lymph node resection, number of abdominal aortic lymph node resection, the total number of lymph node resection, operation time, surgical methods (robot surgery or traditional laparoscopic surgery) and other clinicopathological data were analyzed by logistic regression analysis. Results: (1) Complications of operation: the incidence of operative complications (including intraoperative and postoperative complications) in robot group was significantly lower than that in traditional laparoscopy group [(20.6%, 27/131) vs (34.8%, 101/290); χ(2)=8.620, P=0.003)]. The incidence of intraoperative complications in robot group was lower than that in traditional laparoscopy group [1.5% (2/131) vs 6.2% (18/290); χ(2)=4.368, P=0.037]. The incidence of intraoperative vascular injury in robot group was significantly lower than that in traditional laparoscopy group [0.8% (1/131) vs 5.2% (15/290); χ(2)=4.798, P=0.022]. The incidence of postoperative complications in robot group was also lower than that in traditional laparoscopy group [19.1% (25/131) vs 28.6% (83/290); χ(2)=4.303, P=0.038], but the incidence of postoperative lymphatic leakage in robot group was higher than that in traditional laparoscopy group [10.7% (14/131) vs 5.2% (15/290); χ(2)=4.279, P=0.039]. (2) Clavein-Dindo classification: the incidence of Clavein-Dindo Ⅰ, Ⅲ, Ⅲ, Ⅳ and Ⅴ grade between two groups were respectively 3.8% (5/131) vs 11.0% (32/290), 13.7% (18/131) vs 14.5% (42/290), 3.1% (4/131) vs 8.6% (25/290), 0 (0/131) vs 0.3% (1/290), 0 (0/131) vs 0.3% (1/290), and the incidence of grade Ⅰ (χ(2)=5.684, P=0.015) and Ⅲ (χ(2)=4.361, P=0.037) complications were statistically significant. The incidence of severe complications in robot group (grade Ⅲ and above) was lower than that in traditional laparoscopy group [3.1% (4/131) vs 9.3% (27/290); χ(2)=5.179, P=0.023]. (3) Analysis of influencing factors of surgical complications: univariate analysis showed that BMI (χ(2)=15.801, P=0.000), preoperative anemia (χ(2)=14.299, P=0.000), total number of lymph node resection (χ(2)=10.425, P=0.001), surgical methods (χ(2)=8.620, P=0.003) were related to the occurrence of surgical complications of endometrial carcinoma. Multivariate analysis showed that BMI (OR=0.289, 95%CI: 0.097-0.864, P=0.026), preoperative anemia (OR=0.309, 95%CI: 0.129-0.740, P=0.008), the total number of lymph node resection (OR=0.624, 95%CI: 0.403-0.966, P=0.034) and surgical methods (OR=3.491, 95%CI: 1.030-11.840, P=0.045) were independent risk factors for surgical complications of endometrial carcinoma. Conclusions: Compared with traditional laparoscopic surgery, robot-assisted laparoscopic surgery has fewer complications and lower incidence of severe complications. BMI, preoperative anemia, the total number of lymph node resection and surgical methods are independent risk factors for the occurrence of surgical complications of stage Ⅰ endometrial cancer.

Modulation of Multiple Signaling Pathways of the Plant-Derived Natural Products in Cancer

Natural compounds are highly effective anticancer chemotherapeutic agents, and the targets of plant-derived anticancer agents have been widely reported. In this review, we focus on the main signaling pathways of apoptosis, proliferation, invasion, and metastasis that are regulated by polyphenols, alkaloids, saponins, and polysaccharides. Alkaloids primarily affect apoptosis-related pathways, while polysaccharides primarily target pathways related to proliferation, invasion, and metastasis. Other compounds, such as flavonoids and saponins, affect all of these aspects. The association between compound structures and signaling pathways may play a critical role in drug discovery.

miR-375 inhibits the proliferation and invasion of glioblastoma by regulating Wnt5a

The aberrant expression of microRNA-375 (miR-375) has been proved to be associated with carcinogenesis. However, the role of miR-375 in glioblastoma (GBM) remains unknown. The aim of this study was to investigate biological functions and its molecular mechanisms of miR-375 in GBM cells. In this study, real-time PCR results showed that the level of miR-375 expression in GBM tissues and GBM cell lines (U87 and U251) was decreased. Using MTT assay, Transwell migration and invasion assay, we demonstrated that miR-375 overexpression significantly suppress cell proliferation, cell migration and cell invasion capacity in U87 and U251 cells. However, downregulation of miR-375 had reverse effects on cell proliferation, migration and invasion. Targeting association analysis, dual luciferase assay, RT-PCR and western blot analysis results confirmed that miR-375 could target the 3'UTR of Wnt5a mRNA and regulated its protein expression. Further studies also find overexpression of Wnt5a could significantly reverse miR-375-mediated proliferation, migration and invasion on U87 and U251 cells. Therefore, we concluded that miR-375 inhibited the proliferation and invasion of GBM by regulating Wnt5a and might be a possible therapeutic agent for GBM.

Identification of an (AC)n microsatellite in the Six1 gene promoter and its effect on production traits in Pietrain × Duroc × Landrace × Yorkshire pigs

The Sine oculis homeobox 1 (Six1) gene is important for skeletal muscle growth and fiber specification; therefore, it is considered as a promising candidate gene that may influence porcine growth and meat quality traits. Nevertheless, the association of Six1 with these processes and the mechanisms regulating its expression remain unclear. The objectives of this study were to identify variant sites of Six1 in different pig breeds, conduct association analysis to evaluate the relationship between polymorphisms of these variants and porcine production traits in Pietrain × Duroc × Landrace × Yorkshire commercial pigs, and explore the potential regulatory mechanisms of Six1 affecting production traits. A total of 12 variants were identified, including 10 single- nucleotide variations (SNVs), 1 insertion- deletion (Indel), and 1 (AC)n microsatellite. Association analysis demonstrated that the SNV, g.1595A>G, was significantly associated with meat color (redness, a*); individuals with the G allele had greater a* values (P < 0.05). Moreover, our results demonstrated that the (AC)n polymorphism in the Six1 promoter was significantly associated with weaning weight (P < 0.05), carcass weight (P < 0.05), and thoracic and lumbar back fat (P < 0.01).In addition, we found that the (AC)n variant was closely related with Six1 expression levels and demonstrated this polymorphism on promoter activity by in vitro experiments. Overall, this study provides novel evidence for elucidating the effects of Six1 on porcine production traits as promising candidate and describes two variants with these traits, which are potential reference markers for pig molecular breeding. In addition, our data on the relationship between porcine Six1 expression and the polymorphic (AC)n microsatellite in its promoter may facilitate similar studies in other species.

[Telbivudine for prevention of perinatal transmission in pregnant women infected with hepatitis B virus in immune-tolerant phase: a study of efficacy and safety of drug withdrawal]

OBJECTIVE

To observe the success rate of telbivudine (LdT) for the prevention of perinatal transmission of hepatitis B virus (HBV) and the incidence of alanine aminotransferase (ALT) elevation during LdT treatment and after LdT withdrawal in HBV-infected pregnant woman with high viremia in immune-tolerant phase and receiving LdT treatment at the end of pregnancy, and to evaluate the efficacy of LdT in the prevention of perinatal transmission and the safety for pregnant women.

METHODS

Pregnant women infected with HBV in immune-tolerant phase who had normal ALT levels (≤40 U/L) and high viremia (HBV DNA ≥6 log10 IU/ml) with positive HBeAg were enrolled as subjects. All pregnant women received antiviral treatment with LdT at the end of pregnancy to prevent perinatal transmission of HBV. All infants received standard combined immunoprophylaxis. Failure for prevention of perinatal transmission of HBV was defined as positive HBsAg or HBV DNA in infants 7 months of age (or at one month after the third injection of hepatitis B vaccine). Liver function, HBV DNA, and HBV serological markers were evaluated at baseline, after 1 month of treatment, before childbirth, and 1, 3, and 6 months after drug withdrawal. SPSS 16.0 software was used to analyze the data. Between-group comparison of continuous data was made by t test, and comparison of categorical data was made by chi-square test.

RESULTS

One hundred and four pregnant women (treatment group) received oral administration of 600 mg LdT once a day, and 25 pregnant women (observation group) did not receive any antiviral therapy. The success rate for the prevention of perinatal transmission was significantly higher in the treatment group than in the observation group (100% vs 89.47%, χ (2) = 9.862, P = 0.028). There was no significant difference in the incidence of ALT elevation during treatment and within 6 months after drug withdrawal between the treatment group and the observation group (4.81% (5/104) vs 4.00% (1/25), χ (2) = 0.030, P = 1.000). In the treatment group, the mean HBV DNA at baseline was significantly higher than that before childbirth (8.20±0.78 vs 3.98±0.90 log10IU/ml, t = 6.979, P < 0.001). One hundred patients with drug withdrawal had HBV DNA increased to 8.11±0.80 log10 IU/ml at one month after childbirth.

CONCLUSION

LdT treatment at the end of pregnancy can effectively reduce the incidence of perinatal transmission of HBV in pregnant women with high viremia in immune-tolerant phase. The immediate drug withdrawal after childbirth is safe for the mother. The incidence of hepatitis is low after drug withdrawal.

Enhancing local luminescence in a hollow ZnO microcolumn by antiresonant reflecting

Hollow ZnO microcolumns with size induced photoluminescence and cathodoluminescence properties were prepared by a thermal chemical vapor transport and condensation method. It was found that the luminescence emission could be confined in the nano-sized hollow core and the wavelength dependent light intensity could be influenced by the geometric structure of the ZnO microcolumn, which can act as a hollow optical waveguide. Based on the antiresonant reflection in the optical waveguide, we established a theoretical model to address the field enhancement in the hollow ZnO microcolumn, which systematically clarifies the influence of the geometric structure of the microcolumn on the field enhancement. We report for the first time, the enhanced emission of the near ultraviolet light (working wavelength of 385 nm) along the axial direction of the ZnO microcolumn. The corresponding microsized light emitter has also been obtained. Experiments agree well with both theoretical predictions and computer simulations based on the finite-difference time-domain method with perfectly matched layer boundary conditions. These findings provide valuable information for the application of ZnO micro- and nanostructures in optoelectronic devices.

Effect of lipoic acid combined with paclitaxel on breast cancer cells

Breast cancer is the most common gynecologic tumor globally that threatens women's health. Lipoic acid is a type of antioxidant that can alleviate oxidative stress damage. Studies showed that lipoic acid could inhibit the proliferation of tumor cells in cervical cancer and colon cancer. This paper intends to explore the combined effect of lipoic acid and paclitaxel on breast cancer cells. Breast cancer MCF-7 cells were divided into four groups: control group, lipoic acid group, paclitaxel group, and a combination group. MTT was applied to detect the drugs' influence on breast cancer cell proliferation. A colony formation test was used to determine the effects on breast cancer cell clone formation rate. Western blot was performed to detect the effects on nuclear factor (NF)-κB. Lipoic acid alone can inhibit tumor cell proliferation and clone formation with time dependence. Compared with the control, paclitaxel alone can significantly suppress tumor cell proliferation and clone formation (P < 0.05). Lipoic acid and paclitaxel in combination obviously strengthened their individual inhibitory effects on tumor cells (P < 0.05). Compared with the paclitaxel alone group, the combination group exhibited more remarkable inhibitory effect (P < 0.05). Lipoic acid alone or combined with paclitaxel can inhibit NF-κB expression and inhibit breast cancer cell proliferation.

S-phase kinase-associated protein 2 expression interference inhibits breast cancer cell proliferation

We investigated the expression of S-phase kinase-associated protein 2 (SKP2) in breast cancer tissues, and the effects of SKP2-specific small interfering RNA (siRNA) interference on breast cancer cell proliferation. Thirty subjects provided breast cancer tissue samples and 18 subjects provided normal breast specimens for this study. The expression of SKP2 in breast cancer patient tissues and normal breast tissues was detected by western blotting analysis and reverse transcription-polymerase chain reaction. SKP2-specific siRNA was used to decrease SKP2 expression in breast cancer cell line MDA-MB-231. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect cell proliferation. SKP2 expression in breast cancer tissues was significantly higher than in normal breast tissues (P < 0.05). Two pairs of siRNA specific to SKP2 were required to downregulate SKP2 expression in the breast cancer cell line MDA-MB-231. The MTT assay showed that MDA-MB-231 growth significantly slowed after SKP2 interference. Patients with breast cancer have an increased SKP2 level. Interference in SKP2 gene expression can inhibit breast cancer cell growth, suggesting that SKP2 is potentially a new target for breast cancer therapy.

TBX21 polymorphisms are associated with virus persistence in hepatitis C virus infection patients from a high-risk Chinese population

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and the varied outcomes of the infection depend on both viral and host factors. We have demonstrated that the HCV alternate reading frame protein (F protein) is related to Th1/Th2 bias which is involved in virus persistence in chronic hepatitis C (CHC) patients. The purpose of this study was to test the hypothesis that genetic variants of TBX21 (T cell specific T-box transcription factor) were associated with the outcomes of HCV infection and F protein generation. Three single nucleotide polymorphisms (SNPs) (rs17250932, rs2074190, rs4794067) in the TBX21 gene were genotyped in a case-control study in a cohort of a high-risk group, including 354 healthy controls and 747 CHC patients (190 anti-F protein antibody seronegative patients and 557 anti-F protein antibody seropositive patients). Results showed that the rs4794067 C allele in the TBX21 promoter was significantly more common in CHC patients (OR = 1.335, 95% CI = 1.058-1.684, P = 0.015), exceptionally in anti-F protein seropositive patients (OR = 1.547, 95% CI = 1.140-2.101, P = 0.005), compared with healthy controls. And the risk effect was also significantly high in patients with HCV 1b genotype and mild fibrosis (P = 0.021, P = 0.010, respectively). Compared with the most frequent haplotype TAT, haplotype analysis showed that the distribution of TAC was significantly different between the chronic HCV carrier group and the healthy group, and so was the anti-F antibody seronegativity group and the anti-F antibody seronegativity group (all P < 0.001). Our results suggested that TBX21 variants may be involved in the etiology of this disease.

First Report of Corynespora Leaf Spot Caused by Corynespora cassiicola on Gynura in China

Gynura (Gynura bicolor DC.) is a perennial herbaceous plant in the family Compositae. It is an important Chinese vegetable, and is commonly used as a Chinese herbal medicine. In 2010, a severe leaf spot disease was observed on gynura grown in the main production areas in Tong Nan County, Chongqing City, China. Some farms experienced 60% disease incidence. Symptoms usually began on the lower leaves, as circular to elliptical or irregular spots with concentric rings. Individual spots were dark brown with grayish centers, sometimes coalescing and leading to extensive necrosis. The fungus associated with lesions was characterized as follows: Conidiophores were single or in clusters, straight or flexuous, unbranched, percurrent, cylindrical, pale to dark brown, 87.5 to 375.0 μm long and 5.0 to 10.5 μm wide. Conidia were solitary or catenate, straight to slightly curved, obclavate to cylindrical, 3 to 14 pseudoseptate, 82.8 to 237.5 μm long and 7.0 to 7.8 μm wide, and pale brown. The morphological characteristics of the conidia and conidiophores agreed with the descriptions for Corynespora cassiicola (1). To isolate the causal pathogen, surface-sterilized tissue at the margin of lesions was immersed in 75% ethanol for 30 s, rinsed in sterile water, dried in a laminar flow bench, transferred to PDA, and incubated at 28°C. Four single-spore cultures of the isolates were obtained and named from ZBTK10110637 to ZBTK10110640. All strains were identified as C. cassiicola. The isolate ZBTK10110637 was selected as representative for molecular identification. Genomic DNA was extracted by CTAB (2). The internal transcribed spacer (ITS) region of the rDNA was amplified using primers with ITS1 (5'-TCCGATGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3'). Amplicons were 433 bp (GenBank Accession No. JX867272) and shared 100% similarity with that of C. cassiicola (NRC2-1 No. AB539285.1). To confirm pathogenicity, four isolates were used to inoculate 12 gynura plants (6 weeks old) by mist spray-inoculation with 10⁸ spores/ml suspension in sterile distilled water on the leaves. Control plants were misted with sterile distilled water. After inoculation, all plants were incubated in a greenhouse maintained at 20 to 28°C with relative humidity of 80 to 85%. Five days after inoculation, dark brown spots with a grayish center typical of field symptoms were observed on all inoculated plants. No symptoms were seen on water-treated control plants. The fungus was re-isolated from inoculated plants. The morphological characteristics of isolates were identical with the pathogen recovered originally. This is the first report of C. cassiicola on gynura. References: (1) M. B. Ellis. CMI Mycological Papers 65(9):1-15, 1957. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

First Report of Pseudomonas cichorii Causing Leaf Spot of Vegetable Sponge Gourd in China

A suspect bacterial leaf spot on vegetable sponge gourd (Luffa cylindrical (L.) Roem.) was found in a commercial greenhouse in Pi County, Chengdu City, Sichuan Province, China, in February 2011. Approximately 20 to 30% of plants were affected, causing serious economic loss. Symptoms occurred only on seedlings and consisted of water-soaked, irregularly shaped, black lesions on the surface and margins of cotyledons. A bacterium was consistently isolated on nutrient agar from diseased leaf tissues that had been surface disinfected in 70% ethyl alcohol for 30 s. The bacterium produced small gray colonies with smooth margins, was gram negative, fluoresced on King's B medium, and showed pectolytic activity when inoculated on potato slices. The partial sequences of 16SrRNA gene (1,377 bp) of the bacterium (GenBank Accession No. KC762217), amplified by using universal PCR primers 16SF (5'-AGAGTTTGATCCTGGCTCAG-3') and 16SR (5'-GGTTACCTTGTTACGACTT-3'), shared 100% similarity with that of Pseudomonas cichorii (GenBank Accession No. HM190228). The vegetable sponge gourd isolate was also identified by using the Biolog Microbial Identification System (version 4.2, Biolog Inc., Hayward, CA) as P. cichorii with the following characteristics (1): negative for arginine dihydrolase, gelatin liquefaction, and N₂ production. Positive reactions were obtained in tests for catalase, oxidase, potato rot, utilization of melibiose, and mannitol. Tests were negative for utilization of sucrose, trehalose, D-arabinose, raffinose, cellobiose, and rhamnose. A pathogenicity test was conducted on 4-week-old vegetable sponge gourd plants by spray-inoculation with 10⁸ CFU/ml sterile distilled water on the leaves of 15 vegetable sponge gourd plants and by needle puncture on the stems of 15 other plants with P. cichorii, respectively. Control plants were misted with sterile distilled water or punctured on the stem with a clean needle. Plants were placed in a greenhouse maintained at 28 ± 2°C with relative humidity of 80 to 85%. Symptoms, the same as seen on the original diseased plants, developed after 7 to 10 days on inoculated plants. Control plants remained healthy. The bacterium was readily re-isolated from inoculated plants and identified as P. cichorii using P. cichorii-specific primer hrpla/hrp2a (1). To our knowledge, this is the first report of P. cichorii causing disease on commercially grown vegetable sponge gourd in China. This new finding will provide the basis for developing resources for diagnostics and management, including screening varieties for resistance. References: (1) S. Mazurier et al. J. FEMS Microbiol. Ecol. 49:455, 2004. (2) N. W. Schaad et al., eds. Laboratory Guide for Identification of Plant Pathogenic Bacteria, 3rd ed. APS Press, St. Paul, MN, 2001.

ZnO nanocone: application in fabrication of the smallest whispering gallery optical resonator

ZnO semiconductors at the micro- and nanometre scales are attractive in optical, magnetic, and electronic applications because of their particular features and excellent properties. The whispering gallery mode (WGM) is a general and effective type to amplify the intensity of the luminescence emission, and has gained extensive application in lasing and microcavities. In this contribution, we reported that the smallest whispering gallery optical resonator has been achieved in an individual ZnO nanocone whose diameter gradually reduces from bottom to top in the range of 700 to 50 nm. Using the monochromatic cathodoluminescence (CL) equipment attached at a scanning electron microscopy, we observed the alternating patterns of bright and dark rings from the monochromatic CL image of an individual ZnO nanocone, which is attributed to the WGM-like enhanced luminescence emission when the ZnO nanocone is considered as an optical resonator. The smallest mode number of WGM, N=0, was observed in the ZnO nanocone with a radius of 55 nm for the considered light wavelength of 380 nm, and with a radius of 81 nm for the considered light wavelength of 500 nm, respectively. These results showed that the smallest whispering gallery optical resonator from an individual ZnO nanocone has been fabricated. Experiments are in good agreement with both theoretical predictions and computer simulations based on the finite-difference time domain method with perfectly matched layer boundary conditions. These findings provided valuable information for applications of ZnO micro- and nanostructures in optoelectronic devices.

Impaired spatial working memory and decreased frontal cortex BDNF protein level in dopamine transporter knockout mice

Brain-derived neurotrophic factor (BDNF), one of the key brain neurotrophins, has been implicated in neuronal plasticity and memory. Recent studies document the importance of BDNF for normal long-term memory functions. However, there are few studies of the roles of BDNF in short-term memory. Dopamine is likely to play important roles in BDNF gene expression in specific brain regions, including frontal cortical regions that are implicated in short-term working memory processes that include spontaneous alternation. We have thus tested spatial working memory in dopamine transporter knockout (DAT KO) and wild-type mice. Spontaneous alternation in the Y-maze, an index of short-term spatial working memory in mice, was significantly decreased in DAT KO mice compared to wild-type mice. BDNF protein was significantly decreased in frontal cortex, though not in striatum or hippocampus, of the DAT KO mice. The data support the hypothesis that impaired spatial working memory in DAT KO mice may be related to decreased frontal cortical BDNF in these animals, and document apparent roles for BDNF in a short-term memory process.

Improved field emission properties of thiolated multi-wall carbon nanotubes on a flexible carbon cloth substrate

In this paper we report the observation of enhanced field emission properties from thiolated multi-wall carbon nanotubes (MWCNTs) produced by a simple and effective two-step chemical surface modification technique. This technique implements carboxylation and thiolation on the MWCNTs synthesized by microwave plasma chemical vapor deposition (MPCVD) on the flexible carbon cloth substrate. The resulting thiolated MWCNTs were found to have a very low threshold field value of 1.25 V µm(-1) and a rather high field enhancement factor of 1.93 × 10(4), which are crucial for applications in versatile vacuum microelectronics.

The structure dependent electrochemical-response of novel 1-(4-mercaptobutyl)-4-(2-ferrocenylvinyl)pyridinium bromide SAMs on an au electrode

The 1-(4-mercaptobutyl)-4-(2-ferrocenylvinyl)pyridinium bromide (1-HS(CH2)(4)-4-[(E)-FcCH=CH]C5H4N)+Br- and its hydrogenated product [1-HS(CH2)(4)-4-(-FcCH2CH2)C5H4N]+Br- were synthesized and assembled on an Au electrode to form self-assembled monolayers which showed a structure-dependent electrochemical-response in phosphate buffer aqueous solutions (pH = 7).

[Expression and characterization of t-PA in insect cells]

With the RT-PCR technique, human tissue-type plasminogen activator (t-PA) cDNA was amplified from human melanoma cells. The sequence was proved to be the same as those reported by foreign researchers. The t-PA cDNA containing whole reading frame was inserted into the transfer vector pBacPAK8. The constructed pBac-tPA and the linear BacPAK6 virus DNA were cotransfected with Tn-5B-1 insect cells by lipofectin-mediated transfection method. Eleven pure recombinant viruses were isolated by plaque assay, and one of them, nominated BactPA3, was selected by PCR identification and biological activity comparison. The t-PA activity expressed in serum-containing media reach the highest level at 72 h postinfection. The activity was 3.04 x 10(3) IU/ml, e.g. 1.8 x 10(4) IU/10(6) cells. The highest expression level in serum-free media was almost the same, but needed more time (at 132 h postinfection). SDS-PAGE fibrin autography showed that the molecular weight of the expressed t-PA was about 68 kDa. Its stimulation by fibrinogen, affinity with fibrin and inactivation in plasma were almost the same as the native t-PA purified from human melanoma cell culture. The half-life of t-PA expressed in serum-free media was seven minutes.

[Research on improving rice resistance to the pest by B.t. and SBTi genes]

B.t. gene alone or and SBTi gene together were introduced into two elite indica rice varieties grown in South China by bombardment. And 21 independent transgenic lines containing B.t. gene and 4 independent transgenic lines containing B.t. gene and SBTi gene were obtained. Molecular and genetics analysis for R1 plants showed integration of multiple transgenes occurred at one genetic locus. Northern blot result proved B.t. gene expressed in R2 transgenic plants stably. Bioassays using R2 transgenic plants with leaf-folder (Cnaphalocrosis medinalis), indicated that transgenic rice plants are more resistant to the pest than untransformed control plants. And those transgenic plants containing B.t. and SBTi genes showed more resistance compared with those plants containing B.t. gene.

[Fertile transgenic indica rice from microprojectile bombardment of embryogenic callus]

A reproducible and efficient transformation system for indica rice was developed based on microprojectile bombardment of embryogenic callus. Sufficient globular embryogenic calli were produced within 2-6 weeks from 3-4 week old calli derived from mature embryos. The embryogenic calli were bombarded with the plasmid pFWZ16 containing bar gene and B.t. delta-endotoxin gene. Selection, pre-regeneration, regeneration and rooting were carried out on media with 2-4 mg/L Basta. Partial desiccation treatment was used to increase the efficiency of regeneration. Transformed plantlets were recovered within 4-5 months after mature seeds were plated. From 821 bombarded embryogenic calli of two elite rice varieties popularized in South China, 477 Basta resistant plants of 48 lines were obtained. Results of PCR, Southern blotting, RNA dot blotting, and topical application of Basta demonstrated that the foreign bar gene and B.t. gene were integrated into the genome of transgenic rice plants, and also expressed. 87.5% of the transgenic plants were fertile. Mendelian segregation of the foreign genes was indicated by Basta application and Southern blot analysis of R1 plants.

Mycoplasma orale has a sequence similar to the insertion-like sequence of M. fermentans

Polymerase chain reaction (PCR) using the Mycoplasma fermentans insertion sequence-like element (ISLE) RW primer set amplifies DNA from Mycoplasma orale when more than 1 ng is present in the reaction tube. In this study, amplified products from 11 different clinical isolates and the ATCC prototype of M. orale were sequenced and compared to 206 bp amplicons from eight isolates and the ATCC strain of M. fermentans. The nucleotide sequences of the amplified M. orale products had high sequence homology (88-92%) to those from M. fermentans, but differed at several key positions. The M. orale products contained a DraI restriction enzyme site not found in any of the M. fermentans amplified products. Consistent with this finding, the PCR products from M. orale were digested by DraI while the PCR products from M. fermentans were resistant to DraI digestion. The results suggest that M. orale may carry a similar IS-like element that complicates but does not negate using the ISLE PCR assay designed to detect M. fermentans. It appears possible for the RW primers to amplify M. orale if the mycoplasmas are present at higher concentrations. The amplified products can be differentiated from those from M. fermentans by a rapid DraI restriction endonuclease digestion or by Southern blot analysis using the RW006 internal probe under highly stringent conditions.

[Obtaining transgenic rice plants and their progenies using Agrobacterium tumefaciens]

Rice (Oriza sativa L.) suspension cells of Taipei 309 were co-cultivated with A. tumefaciens stran EHA101 harbouring binary vector pBYT2 for 3 days in the presence of vir inducer, 100 mumol/L acetosyringone (AS). After 2 months of continuous selection, 17 stable hygromycin-resistant, GUS-positive calli were recovered from 364 suspension cell clusters co-cultivated with A. tumefaciens. 10 putative transgenic R0 plants obtained from 8 tansformed calli and their progenies were analyzed for the integration and expression of foreign genes. Southern blot analysis of R0 and R1 generations indicated that foreign genes had been stably integrated in the genome of transgenic rice and sexually transmitted. One of the transgenic lines showed 5 copies of T-DNA integration, while the others had only one copy. Histochemical staining observation and fluorometric assay of GUS activity in transgenic rice cells and plants showed ubiquitin promoter from maize was highly effective in driving the expression of gus reporter gene in transgenic rice cells. GUS protein and its activity were also investigated through ndPAGE-X-Gluc staining assay, and it was found that the GUS protein in transgenic rice cells was smaller in size than the standard GUS protein (Sigma Co. G0786) but as large as that from E.coli HB101 (pBI121). This study suggested that Agrobacterium-mediated transformation of plant is an efficient and reliable method to introduce foreign genes into rice.

Two-dimensional Raman-Nath acousto-optic bistability by use of frequency feedback

From the frequency dependence of the optical transmission characteristics of Raman-Nath acoustic-optic diffraction, the dynamic equations and steady-state solutions of a two-dimensional Raman-Nath acousto-optic bistable system are derived. In this system, feedback is realized by use of a diffracted light beam to control the frequency of the acoustic-optic driver. The curves of light output versus input corresponding to several orders of the diffracted beams are obtained by theoretical analysis. They can all lead to bistability. The amount of hysteresis is a function of the order of the diffracted beam, the bias frequency, and the feedback coefficient. Experimental results are presented and compared with theoretical analyses.

Integration and expression of human growth hormone gene in Caladium bicolor

Human growth hormone (hGH) gene has been inserted into the plasmid pLGV1103 to give the recombinant plasmid pLB-9. It has been introduced into the agrobacterium containing plasmid pGV3850. The recombinant Ti plasmid pGL198(hGH) has been obtained by homologous recombination. The monocotyledon Caladium bicolor has been transferred with pGL198 (hGH) with the leaf-disk co-cultivation method, and transgenic plants have been regenerated. The results of nopaline analysis, NPT II detection Southern blot and Western blot show that the hGH gene was integrated into the genome of Caladium bicolor, and a 22-kD protein was synthesized in the transgenic plants.

[Classification and treatment of torsades de pointes (TdP): a report of 11 cases]

A clinical analysis of 11 cases with TdP was reported. These patients were divided into two groups: 9 cases with long QT syndrome and 2 with normal QT interval. All of the patients suffered from coronary heart disease with various concomitant ailments, such as pulmonary heart disease (1 case), atrioventricular block (5 cases with complete or type II second degree AV block), hypokalemia (7 cases). In one case the TdP was caused by aminodarone administration. The principle of treatment included removing the inducing causes, treating the primary diseases and interrupting TdP. All patients who had hypokalemia were treated with potassium chloride. 7 of 9 cases showed effective response to treatment with magnesium sulfate. The patients with long QT syndrome failed to respond with MgSO4. Severe bradycardia should be treated with isoprenaline. Only one patient had pacing therapy and another received electric conversion. According to our experience, for patients of TdP with long QT syndrome class Ia and III antiarrhythmic agents were contraindicated, but those with normal QT interval can take these drugs.

Cytotoxic activity of trewiasine in 4 human cancer cell lines and 5 murine tumors

Trewiasine (TWS) is a mytansinoid compound. It possessed a significant cytotoxic activity against various human cancer cell lines in vitro. U937 cells, which were more sensitive to the TWS, required TWS 1 microgram.ml-1 to inhibit cell growth over 90% (P less than 0.01). TWS also showed activities against murine tumors in vivo, such as the ascitic tumors S180, hepatoma, U14, and solid tumor Lewis lung carcinoma. Depression of leukocytes was not seen when mice were given ip TWS 10 or 50 micrograms.kg-1.d-1 x 7 d. TWS 0.1-1 micrograms.ml-1 caused no sister chromatid exchange induction in Chinese hamster cell line V79.

[Cytological examination of bronchoalveolar lavage fluid and its clinical significance in patients with diffuse interstitial lung diseases]

Cytological examination of bronchoalveolar lavage fluid (BALF) was carried out in 48 patients with diffuse interstitial lung diseases based on chest roentgenography. 7 cases manifested with respiratory symptoms but without any abnormality on both chest roentgenogram and fibroptic bronchoscopy served as controls. The total cell counts of BALF in the study group were all higher than those of the control group (3.1 x 10(5)/ml) and the differential count of the cells showed that neutrophilic granulocytes was found in patients with fibrosing alveolitis, Neutrophilic granulocytes accounted for 21.3 +/- 2.4% of all the cells and the percentage was significantly higher than that of the control group (1.8 +/- 0.5% P less than 0.01). On the contrary, lymphocytosis was found in patients with allergic alveolitis and sarcoidosis; lymphocytes accounted for 30.8 +/- 5.3% and 29.0 +/- 1.1% of all the cells in these two diseases respectively and the percentage was also higher than that of the control group (3.0 +/- 0.6% P less than 0.01). However, the differential cell count of BALF in alveolar carcinoma showed no significant difference with that of the control group (P greater than 0.05). The factors influencing the quality control of both BAL and cytological examination were evaluated and the clinical significance of these results was discussed.

Somatic embryogenesis and plantlet regeneration in the soybean Glycine max

A tissue culture procedure for the regeneration of somatic embryos and plantlets from somatic cells of the soybean Glycine max is described. Bean pods of soybean cv. TGM119 were immersed in liquid nitrogen for 20 minutes. Young embryos were excised from the immature seeds and cultured to form calli. Calli grown from the young embryos were incubated in liquid culture for two weeks. The liquid suspension culture was filtered to obtain single cells. The soybean cells were cultured for one month in a liquid medium in hanging drop cultures for development into proembryoids. The proembryoids were maintained on a solid growth medium for 40 days. The resultant callus tissue was transferred into MS media containing selected combinations and concentrations of 2,4-Dichlorophenoxyacetic acid, Naphthaleneacetic acid, Kinetin, Benzyladenine and Indoleacetic acid. In the presence of Benzyladenine (0.2 mg/l) and Indoleacetic acid (0.01 mg/l), globular and heart shaped somatic embryos were formed on the surface of the calli. Calli containing somatic embryos were transferred into liquid medium and incubated under low light conditions. After six months further incubation, more than 1,000 plantlets and a large number of somatic embryoids at various developmental stages were obtained per flask.

Electric field mediated stable transformation of carrot protoplasts with naked DNA

We have developed an electroporation procedure for the transformation of carrot protoplasts with Ti-plasmid DNA from Agrobacterium tumefaciens. The uptake of pTiC58 into carrot protoplasts was mediated by high voltage electrical pulses at field strengths from 0.5 to 3.8 kV/cm. Protoplast regeneration, somatic embryogenesis and plantlet regeneration were unaffected by the electroporation conditions selected for DNA uptake. Uptake of plasmid pTiC58 resulted in hormone independent regeneration of carrot protoplasts. Transformed somatic embryos were detected in carrot cultures 45 days after electroporation. The transformed somatic embryos developed into teratomas which synthesized nopaline. Hybridization was obtained between a labeled T-DNA fragment from pTiC58 and DNA fragments from 4 month old teratomas regenerated from electro-transformed protoplasts. Based on the number of somatic embryos regenerated after electro-transformation, a frequency of 1.6×10(2) transformants/10(4) somatic embryos/μg pTiC58 DNA was obtained.