[A study on the relationship between tree age and bark quality in Magnolia officinalis]

Contents of magnolol and honokiol in 76 samples of Magnolia officinalis collected from 11 counties in Zhejiang, Fujian, Sichuan, Guangxi, Hunan, Jiangxi and Hubei are analyzed by means of HPLC. A study on the effect of tree age on effective ingredients in Magnolia offcinalis shows that the influence of tree age on the content of magnolol and honokiol is correlated with the varieties under cultivation, but a small effect on the content of the phenols with an indent at the tip of leaves. The content of magnolol in other types of leaves increases rapidly with increase in age, diameter of the trunk and thickness of the bark, with not many changes found at the age of 12 or up. Increase in age may be favorable to the full expression of oily characteristic. These results provide a scientific base for the determination of optimal time for harvesting bark from artificially established Magnolia officinalis stands.

Optically encoded second-harmonic generation in germanosilicate glass by a femtosecond laser

Second-harmonic generation in germanosilicate glasses was encoded by coherent superposition of the 810-nm fundamental and the 405-nm second-harmonic light of a femtosecond laser. The difference spectra between the absorption spectra of the glasses before and after preparation were measured. An evident correlation between the induced second-order nonlinearity and the creation of a Ge electron center was observed, suggesting that a band-to-band transition by multiphoton absorption is probably responsible for the photoinduced second-harmonic generation.

[Isolating, cloning, and sequencing of HPV16E6E7 gene from a cervical carcinoma biopsy in Shandong Province]

OBJECTIVE

In order to study the structure specificity of HPV16E6E7 gene of a Chinese patient of cervical carcinoma in Shandong province.

METHODS

The tissue DNA were abstracted from cervical carcinoma biopsies and the type of HPV was identified by HPV multiple primers PCR. HPV16E6E7 gene was amplified by PCR from the cervical carcinoma tissue DNA with the infection of HPV16 type only, and then cloned the E6E7 gene into pALTERI vector. After sequencing the double strand, the gene was compared with the prototype E6E7 gene of HPV16.

RESULTS

A new recombinant plasmid was constructed and named HPV16E6E7-SD. Sequencing results showed one mutation in HPV16E6E7-SD, the 557th neocleotide in the viral neocleotide sequence "T" was changed into "C", and caused the termination cordon TAA of E6 gene to convert into a Gln cordon CAA.

CONCLUSIONS

There is a structure difference between HPV16E6E7-SD and the standard strain.

ERK MAP kinase activation is required for acetylcholine receptor inducing activity-induced increase in all five acetylcholine receptor subunit mRNAs as well as synapse-specific expression of acetylcholine receptor epsilon-transgene

The AChR is a pentamer of four different subunits in a stoichiometry of alpha2betagammadelta in embryonic and alpha2betaepsilondelta in adult animals. Transcription of AChR subunit genes is most active in synaptic nuclei in adult skeletal muscle cells, and is regulated by neural factors such as ARIA. We report here that ARIA up-regulated specifically the expression of all five AChR subunits in C2C12 cells. The mRNA level of erbB2, erbB3, rapsyn, MuSK, SHP-2 and beta-actin remained unchanged in response to ARIA stimulation in C2C12 cells. The ARIA-induced increase in AChR subunit expression in C2C12 cells was inhibited by the erbB kinase inhibitor tyrphostin AG1478 and the MEK inhibitor PD98059, but not by the PI3 kinase inhibitor wortmannin, suggesting an important role of the erbB protein tyrosine kinases and MAP kinase in the regulation of the expression of the five different AChR subunits. To determine the signaling pathways in vivo, we studied the expression of reporter genes driven by the epsilon-promoter in injected muscles. The in vivo expression of the epsilon-transgene was inhibited by co-expression of dominant negative mutants of key components in the MAP kinase pathway including ras, raf and MEK, but not the dominant negative mutant of PI3 kinase. These results suggest that ERK MAP kinase activation is required for ARIA-induced increase in all five AChR subunit mRNAs as well as synapse-specific expression of AChR epsilon-transgene.

[Research on the oncogenesis of cervical epithelial cells co-induced by human papillomavirus and human cytomegalovirus]

OBJECTIVE

The carcinogenesis of the human cervical carcinoma is known closely associated with human papillomavirus (HPV). The purpose of this article is to identify whether another sexually transmitted factor, human cytomegalovirus (HCMV) plays as a co-factor role in the carcinogenesis.

METHODS

Human cervical epithelial cells immortalized by HPV16 were transfected with IE gene of HCMV. The condition and efficiency of IE gene were examined.

RESULTS

It was showed that the cervical epithelial cells could be completely transformed into malignant by HPV 16 and IE gene of HCMV and tumor was formed by injecting the transformed cells in nude mice.

CONCLUSION

The co-operation effect of HPV and HCMV auailed the oncogenesis of human cervical carcinoma and moreover, the cellular and molecular biological mechanism was discussed.

Subset-based training and pruning of sigmoid neural networks

In the present paper we develop two algorithms, subset-based training (SBT) and subset-based training and pruning (SBTP), using the fact that the Jacobian matrices in sigmoid network training problems are usually rank deficient. The weight vectors are divided into two parts during training, according to the Jacobian rank sizes. Both SBT and SBTP are trust-region methods. Compared with the standard Levenberg-Marquardt (LM) method, these two algorithms can achieve similar convergence properties as the LM but with fewer memory requirements. Furthermore the SBTP combines training and pruning of a network into one comprehensive procedure. The effectiveness of the two algorithms is evaluated using three examples. Comparisons are made with some existing algorithms. Some convergence properties of the two algorithms are given to qualitatively evaluate the performance of the algorithms.

[Study on the relationship between provenance, leaf type and quality in Magnolia officinalis]

An analysis of effective ingredients in 20 to 29 year old Magnolia officinalis of three different leaf types coming from various sources shows that the content of phenols differ extremely significantly in various leaf types which are a key to determination of quality of Magnolia officinalis also varies significantly among different sources which only have a significant effect on the content of magnolol. Varieties and types cultivated in different places are responsible for the variation in content of magnolol. The conclusions obtained from this study coincide with the traditional insight into quality of Magnolia officinalis.

[Human interleukin-13 cDNA cloning and expression]

OBJECTIVE

To construct an efficient expression system for HIL-13 in prokaryotic cells.

METHODS

After Amplified by RT-PCR, The cDNA fragment encoding HIL-13 was inserted into pGEX-2T plasmid and expressed under induced condition.

RESULTS

HIL-13 cDNA was obtained. Recombinant plasmid pGEX-2T HIL-13 was constructed and sequenced, the inserted fragment of the recombinant plasmid was confirmed to be HIL-13 cDNA. HIL-13 was expressed as a fusion protein with glutathione-s-transferase (GST-HIL-13, MW = 39,000).

CONCLUSIONS

(1) HIL-13 cDNA has been obtained from T lymphocytes. (2) The rate of expression of HIL-13 in prokaryotic cells is about 37%.

[Chemical constituents of the leaves of Crataegus scabrifolia (Franch.) Rehd]

OBJECTIVE

To explore the medicinal resources of Crataegus and seek compounds with pharmaceutical effects.

METHOD

Column chromatography was employed for the isolation and purification of constituents and the structures were elucidated by spectral analysis and chemical evidence.

RESULT

Six compounds were obtained and identified as rutin, hyperoside, vitexin, ursolic acid, daucosterol, and nonacosanol.

CONCLUSION

The main constituents of the leaves of Crataegus scabrifolia are flavonoids.

[Cloning of human papillomavirus type 16 E7 gene and expression in E. coli]

OBJECTIVE

To study the biological activity of the E7 gene of human papillomavirus 16 (HPV16).

METHODS

E7 gene from the cervical carcinoma of Chinese women was amplified by the PCR. The E7 DNA was sequenced and compared with the prototype E7 gene of HPV 16.

RESULTS

It showed no mutations. However when E7 gene was inserted into the prokaryotic expression vector pGEX-2T and the fused E7 protein was efficiently expressed in E. Coli (DH5 alpha). The E7 antibody could combine specifically with this fused protein by Western blot technique.

CONCLUSIONS

The result might aid for epidemiological investigation and preparation of the vaccine.

Regulation by ARIA/neuregulin of acetylcholine receptor gene transcription at the neuromuscular junction

Transcription of genes encoding nicotinic acetylcholine receptor (AChR) subunits (alpha, beta, gamma or epsilon, and delta) is highest in nuclei localized to the synaptic region of the muscle which contributes to maintain a high density of AChRs at the postjunctional membrane. ARIA (AChR inducing activity) is believed to be the trophic factor utilized by motor neurons to stimulate AChR synthesis in the subsynaptic area. ARIA stimulates tyrosine phosphorylation of the erbB proteins and activates the MAP kinase pathway which is required for the ARIA-mediated induction of AChR genes.

Weight-value convergence of the SOM algorithm for discrete input

Some insights on the convergence of the weight values of the self-organizing map (SOM) to a stationary state in the case of discrete input are provided. The convergence result is obtained by applying the Robbins-Monro algorithm and is applicable to input-output maps of any dimension.

A systematic and effective supervised learning mechanism based on Jacobian rank deficiency

Most neural network applications rely on the fundamental approximation property of feedforward networks. Supervised learning is a means of implementing this approximate mapping. In a realistic problem setting, a mechanism is needed to devise this learning process based on available data, which encompasses choosing an appropriate set of parameters in order to avoid overfitting, using an efficient learning algorithm measured by computation and memory complexities, ensuring the accuracy of the training procedures as measured by the training error, and testing and cross-validation for generalization. We develop a comprehensive supervised learning algorithm to address these issues. The algorithm combines training and pruning into one procedure by utilizing a common observation of Jacobian rank deficiency in feedforward networks. The algorithm not only reduces the training time and overall complexity but also achieves training accuracy and generalization capabilities comparable to more standard approaches. Extensive simulation results are provided to demonstrate the effectiveness of the algorithm.

Identification of an element required for acetylcholine receptor-inducing activity (ARIA)-induced expression of the acetylcholine receptor epsilon subunit gene

Acetylcholine Receptor (AChR)-inducing activity (ARIA) is believed to be the trophic factor utilized by motoneurons to stimulate AChR synthesis in the subsynaptic area. Among the four AChR subunit genes, the epsilon subunit gene is strictly expressed in nuclei localized to the synaptic region of the muscle. To understand mechanisms of the regulation of synapse-specific transcription, we studied the promoter activity of the 5'-flanking region of the AChR epsilon subunit gene in response to ARIA. Transgenes containing the wild type or mutant 5'-flanking regions upstream of a luciferase gene were transfected in C2C12 muscle cells. The promoter activity of these transgenes was determined by assaying activity of expressed luciferase. Analyzing a combination of 5' deletion and site-directed mutants, we identified a 10-nucleotide element (position -55/-46), which was crucial for ARIA-induced expression from the epsilon subunit promoter. This element was named ARE for ARIA-responsive element. Mutation of ARE greatly diminished ARIA-induced transgene expression and deletion of ARE abolished completely the ARIA response. Electrophoretic mobility shift analyses revealed a DNA binding activity in muscle nuclear extract that interacted with ARE. Such interaction was enhanced by ARIA stimulation of muscle cells and appeared to be dependent on nuclear protein phosphorylation.

Self-organization of firing activities in monkey's motor cortex: trajectory computation from spike signals

The population vector method has been developed to combine the simultaneous direction-related activities of a population of motor cortical neurons to predict the trajectory of the arm movement. In this article, we consider a self-organizing model of a neural representation of the arm trajectory based on neuronal discharge rates. As self-organizing feature map (SOFM) is used to select the optimal set of weights in the model to determine the contribution of an individual neuron to an overall movement representation. The correspondence between movement directions and discharge patterns of the motor cortical neurons is established in the output map. The topology-preserving property of the SOFM is used to analyze the recorded data of a behaving monkey. The data used in this analysis were taken while the monkey was tracing spirals and doing center-->out movements. The arm trajectory could be well predicted using such a statistical model based on the motor cortex neuronal firing information. The SOFM method is compared with the population vector method, which extracts information related to trajectory by assuming that each cell has a fixed preferred direction during the task. This implies that these cells are acting along lines labeled only for direction. However, extradirectional information is carried in these cell responses. The SOFM has the capability of extracting not only direction-related information but also other parameters that are consistently represented in the activity of the recorded population of cells.

[Study on the quality standard of Hippophae rhamnoides oil for pharmaceutical uses]

The quality control methods of the seed oil and fruit oil of Hippophae rhamnoides are studied. The physical and chemical factors are determined and the identification and determination methods for the bioactive compnents a-tocopherol and carotenes are established.

Induction of acetylcholine receptor gene expression by ARIA requires activation of mitogen-activated protein kinase

Transcription of genes encoding nicotinic acetylcholine receptor (AChR) subunits (alpha, beta, gamma or epsilon, and delta) is highest in nuclei localized to the synaptic region of the muscle, which contributes to maintain a high density of AChRs at the postjunctional membrane. ARIA (AChR inducing activity) is believed to be the trophic factor utilized by motor neurons to stimulate AChR synthesis in the subsynaptic area. To elucidate the signaling mechanism initiated by ARIA, we established stable C2C12 cell lines carrying the nuclear lacZ gene under the control of the mouse epsilon subunit promoter or chicken alpha subunit promoter. ARIA stimulated tyrosine phosphorylation of erbB proteins in these C2C12 cells within 15 s with a peak at 5 min. Immediately following tyrosine phosphorylation of erbB proteins, mitogen-activated protein (MAP) kinase was activated which occurred within 30 s and peaked at 8 min after ARIA stimulation. Concomitantly, expression of AChR genes was induced by ARIA. ARIA-induced AChR subunit transgene expression was observed only in differentiated myotubes and not in myoblasts, suggesting that downstream signaling component(s) are regulated in a manner dependent on the myogenic program. Inhibition of the MAP kinase activity by using a specific MAP kinase kinase inhibitor or by overexpressing dominant negative mutants of Raf or MAP kinase kinase attenuated or abolished the ARIA-induced activation of AChR alpha and epsilon subunit gene expression. These results indicate that regulation of AChR gene expression by ARIA in C2C12 cells requires activation of the MAP kinase signaling pathway.

Differentiation of pseudocondyloma of vulva and condyloma acuminata by dot blot hybridization and polymerase chain reaction

This study differentiated pseudocondyloma of vulva from condyloma acuminata using dot blot hybridization and polymerase chain reaction (PCR). A total of 27 cases of pseudocondyloma of vulva and 65 cases of condyloma acuminata were selected for the study. The genital lesions were examined clinically and were biopsied. Each biopsy was subjected to histological examination and HPV DNA analysis by dot blot hybridization and PCR. Dot blot analysis detected HPV DNA in 19(82.6%) out of 23 cases of condyloma acuminata and 2(25%) out of 8 cases pseudocondyloma of vulvae (P < 0.05). PCR detected HPV DNA in 51(92.7%) out of 55 cases of condyloma acuminata, compared with none in 23 cases of pseudocondyloma (P < 0.001). HPV DNA was present in the majority of condyloma acuminata specimens, HPV 6 and 11 were the predominant types. Peudocondyloma is probably not associated with HPV. PCR was the most sensitive and useful technique for HPV DNA detection.

Picosecond optical bistability in metallophthalocyanine-doped polymer film waveguides

Ultrafast optical bistability was observed in a planar optical waveguide made with a 2,9,16,23-tetraoctadecanoylamido-substituted vanadyl phthalocyanine-doped polystyrene film. Input-output curves with hysteresis characteristics were measured with laser pulses of 60-ps pulse width at 532 nm. The switchup and switchdown times were less than 10 and 20 ps, respectively. The origin of the nonlinearity giving rise to optical bistability was predominantly electronic effects.

[The reversing effect of HPV-16 E6E7 gene antisense plasmid on the HPV-16 positive human cervical carcinoma cells]

Antisense reconstruct, p16as E6E7Neo, harboring HPV-16E6E7 gene of which the expression is regulatable by dexamethasone was constructed. Calcium phosphate mediated transfection was employed to transduce this antisense reconstruct into HPV-16 positive CasKi cell line and HPV negative C-33A cell line (both derived from human cervical carcinoma) respectively. After dexamethasone was added into the culture medium to induce the expression of E6E7 antisense gene, the malignity of CasKi cells were reversed, while the growth characteristics and malignity of C-33A cells were unchanged. The results show that the reversing effect on CasKi cell is specific and mediated by inhibition of expression of E6E7 gene. It also demonstrated a more profound pathogenic role of HPV-16 E6E7 gene in the tumorogenesis of cervical carcinoma and provides a possibility for gene therapy of this tumor.

[Human papillomavirus, human cytomegalovirus and p53 gene in cervical carcinoma]

OBJECTIVE

To investigate the role of human papillomavirus (HPV) human cytomegalovirus (HCMV) infections and p53 gene mutations in the oncogenesis of cervical cancer and to clarify the association between p53 inactivation and the presence of HPV DNA.

METHODS

We examined 38 primary cervical carcinomas and 21 normal cervical specimens for the presence of HPV and HCMV DNA sequences by multiple primers PCR and nest primers PCR. The structure of p53 gene (exons 6-8) was also analyzed by PCR-SSCP silver staining method.

RESULTS

Mutations of p53 gene (exon 7) were detected in 2 of 38 tumors. One of the cases with p53 mutation was positive for HPV 16 and two positive for HCMV. HPV 16 and 18 infections were noted in 63.2% (24/38) of the tumors, the positive rate of HCMV was 84.2% (32/38). However, HPV 16,18 and HCMV infection occurred in 4.8% and 38.1% respectively in 21 normal cervical specimens. 21 of the 24 HPV 16,18 positive tumors were also HCMV positive, but none of the normal cervical tissues was infected with both HPV and HCMV.

CONCLUSION

Detection of p53 mutations in cervical carcinoma is infrequent and apparently independent of HPV infection. Cervical carcinoma is strongly associated with HPV 16 and 18 infection. A synergistic interaction may occur between HPV and HCMV infections in the oncogenesis of cervical cancer.

Light-induced noncentrosymmetry in acceptor-donor-substituted azobenzene solutions

Light-induced noncentrosymmetry was achieved experimentally in acceptor-donor-substituted azobenzene solutions and observed by phase-matched nondegenerate six-wave mixing. The microscopic origin of the induced noncentrosymmetry was found to be orientational hole burning, which was distinguished directly with net orientation of molecules by experimental observations. The decay time of the induced noncentrosymmetry depended on the rotational orientation time of the sample's molecule, which varied linearly with the viscosity of the solvent.