Study on secondary metabolites from sponge-symbiotic Streptomyces sp. LHW2432 / 药学实践杂志

Objective To discover the medicinal active molecules from the fermentation extract of sponge-symbiotic Streptomyces sp. LHW2432. Methods Compounds were isolated and purified from the fermentation extract of LHW2432 by silica gel, ODS chromatographic columns, and HPLC. The structures of the compounds were elucidated based on the analyses of modern spectrum technologies and the related literatures research. Through plate coating method and broth microdilution method, the antimicrobial activities were tested by the indicator strains of Bacillus mycoides, methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium smegmatis, Candida Albicans, and Escherichia coli. Results Five compounds were discovered and their structures were identified as descycloavandulyl-lavanduquinocin (1), N-acetyltyramine (2), phomapyrone C (3), germicidin A (4), and germicidin I (5). Compound 1 showed inhibitory activities against MRSA (MIC, 100 μg/ml) and M. smegmatis (MIC, 64 μg/ml), respectively. Conclusion Five compounds were discovered from LHW2432, among which compound 1 was a new natural product and could be used as a precursor of the tricyclic carbazole alkaloids with neuroprotective activity. Moreover, compound 1 showed weak inhibitory activities against gram-positive pathogenic bacteria.

Phylogenetic study of drug resistance genes from clinical isolates of Helicobacter pylori / 中华医学遗传学杂志

<p><b></b>To carry out phylogenetic analysis for drug-resistance genes from clinical isolates of Helicobacter pylori (Hp) among patients with gastric diseases from Tibet, China.</p><p><b>METHODS</b>Hp strains were isolated and cultured from saliva and gastric mucosal tissues derived from patients with gastric diseases. Nine strains (including 5 isolated from oral tissues, 1 isolated from gastric tissues, and 3 representative strains of SS international standard strains used for animal models) were tested for common antibiotic resistance. Together with an ACTT 11637 international standard strain, these were subjected to re-sequencing to obtain drug-resistance genes. Such genes from various sources were compared with the resistance genes of Hp strains recorded by the NCBI website. Combined with results of drug-resistance experiments, correlation between molecular evolution and drug-resistance was analyzed.</p><p><b>RESULTS</b>Testing of gastric mucosal tissues and salivary samples from 217 patients has found 89 Hp strains, which yielded a total infection rate of 41.01%. The resistance rates of 9 representative Hp strains for clarithromycin, amoxicillin, metronidazole, levofloxacin and tetracycline were 77.8%, 77.8%, 44.4%, 77.8%, and 77.8%, respectively. Compared with the reference strain, the similarity between clarithromycin-resistance genes was 99%, and that between amoxicillin- and metronidazole-resistance genes was 96%-97%. A2143G mutation was also found in clarithromycin-resistant genes of three Hp strains.</p><p><b>CONCLUSION</b>The sensitivity of Hp to metronidazole is much higher in patients from Tibet region, and the sensitivity of Hp to clarithromycin, amoxicillin, levofloxacin and tetracycline is poor. Resistance mutations are consistent with drug resistance.</p>

In vivo distribution of luciferase gene-labeled bone marrow mesenchymal stem cells infused through different approaches / 中国组织工程研究

BACKGROUND:Most bone marrow mesenchymal stem cel s are infused intravenously and have very low efficiency of homing to the bone marrow. However, cel infusion via the femoral approach is little reported. OBJECTIVE:To explore the distribution of luciferase gene modified red fluorescent protein transgenic bone marrow mesenchymal stem cel s in vivo through different infusion routes. METHODS:Luciferase gene modified bone marrow mesenchymal stem cel s at different gradients (5×106, 1×106, 1×105, 1×104) were seeded or injected into the in vitro pore plate or free femurs to observe the fluorescence imaging and select the best concentration of cel s. Luciferase gene modified bone marrow mesenchymal stem cel s at the best cel concentration were injected into the mice via the femur and the tail vein, respectively. The distribution of fluorescence and cel number in the mice were explored by using bioluminescence, pathological examination, flow cytometry and quantitative PCR. RESULTS AND CONCLUSION:Ex vivo fluorescence intensity of luciferase gene modified bone marrow mesenchymal stem cel s was positively correlated with the cel concentration;fluorescent cel s in vivo appeared in the femur first and then quickly spread to the lungs in the femur group, while fluorescent cel s in the tail vein group spread to the lungs quickly after cel infusion. Fluorescent cel s could be seen in the spleen, liver and other organs 24 hours later in the two groups. The distribution and migration of cel s in mice could be observed successful y by bioluminescence;5 minutes after cel infusion, the lungs of mice in the two groups began to emit fluorescence that could spread to the liver, spleen and other tissues 24 hours later, and the fluorescence intensity reached its peak after 15 minutes. The distribution of bone marrow mesenchymal stem cel s in mice had no significant difference between the femur group and the tail vein group. To conclude, cel injection through the bone marrow cavity and tail vein fails to promote the homing of bone marrow mesenchymal stem cel s to the bone marrow.

Analysis of Electric Stress in Human Head in High-frequency Low-power Electromagnetic Environment / 生物医学工程学杂志

Action of electromagnetic radiation exerting on human body has been a concerned issue for people. Because electromagnetic waves could generate an electric stress in a discontinuous medium, we used the finite difference time domain (FDTD) as calculation methods to calculate the electric stress and its distribution in human head caused by high-frequency low-power electromagnetic environment, which was generated by dual-band (900 MHz and 1 800 MHz) PIFA antennas with radiated power 1 W, and we then performed the safety evaluation of cell phone radiation from the angle whether the electric stress further reached the human hearing threshold. The result showed that there existed the electric stress at the interface of different permittivity organization caused by the two kinds of high-frequency low-power electromagnetic environment and the maximum electric stress was located at the interface between skin and air of the phone side, and the electric stress peak at skull did not reach the threshold of auditory caused by bone tissue conduction so that it can not produce auditory effects.

Detection of DNA virus in respiratory samples of children by multiplex PCR combined with RDB / 中国医师杂志

Objective To develop multiplex polymerase chain reaction (PCR) combined with reversedotblothy bridization (RDB) method for detection of DNA virus in respiratory samples,and provide a surveillance and rapid diagnosis tool of acute viral respiratory infection.Methods We designed multiple PCR primers and the probes referenced to virus nucleic acid sequences in the National Center for Biotechnology Information (NCBI) database,and fixed specific oligonucleotide probes on the nylon membrane.After multiple PCR amplification of virus DNA of human bocavirus (hBOV),karolinska Institutet (KI),adenovirus (AdV),Washington University polyomaviros (WUPyV),and human parvovirus B19 (HPVBI9),the denaturalized amplification products were hybridized with various specific probes,followed by visualization and analysis of the results.The sensitivity and specificity were tested.At the same time,108 cases of clinical specimens of multiple PCR products were analyzed by reverse spot hybridization detection,and compared to the results of culture method.Results The specific probes of multiple PCR-RDB only hybridized with corresponding amplification products without cross-hybridization reaction with other pathogen.The sensitivity of RDB hybridization was 1 colony-forming units (CFU).The positive rate of 34.26％ (37 cases out of 108 cases) with PCR-RDB method was significandy higher than that 27.78％ (30 cases out of 108 cases) with common test method.Conclusions The multiplex PCR combined with RDB might become a rapid and simple method to detect the DNA virus in respiratory samples,which might be a promising tool for clinical application.

A study on bio-electrochemical method for detecting environment-polluted germs / 生物医学工程学杂志

Hyperplasia of germs in biologic cell can consume certain amount of oxygen and thus will lay the foundation on which to metabolize and produce some substance. Using a Biologic cell, we have designed a kind of electric equipment for measurement which can quickly detect the environment-polluted germs, and take a sample of the environment-polluted germs in fresh milk and the microzyme in the process of beer produced. Adding proper amount of bio-coenzyme and ion-incentive to the germs liquor, we use the electric equipment to detect the sample in order to investigate the process of electron generation and germ's metabolization, including the measurement of the oxidation-reduction between the pole and the coenzyme, and the electrochemistry process of every reaction matter in the liquor. The result of our study shows that the method can effectively check the germ's number in fresh milk, and when compared to the traditional method (plate cultivating germs), it has the advantages of quickness, convenience and timeliness.

Mechanism of Biological Effects of ELF Pulsed Electromagnetic Wave on Cells / 航天医学与医学工程

Objective To observe changes of cytosolic Ca2+ levels before and after irradiation by ELF pulsed electromagnetic waves and to study the mechanism of these changes.Methods Basing on the result from experiment,time-frequency analysis was applied to analyze the bio-effects of ELF pulsed electromagnetic field on cytosolic Ca2+ levels.Results The PHMx(t,?)isoline of cytosolic Ca2+ levels of the cells before(a)and after(b)irradiation by ELF pulsed electromagnetic field was given.Electrohydrodynamic instability and a crystalline liquid biomembrane were applied to explain the mechanism of biological effects on the cells.Conclusion The cytosolic Ca2+ concentration represents a well-defined pattern of spectrum in time-frequency domain,containing continuous and dispersive spectral components.The circs which was considered to induce bio-effects in time-frequency domain presented two unique properties:the continuous spectrum of cellular Ca2+ fluctuations in time-frequency domain was narrowed by the high-energy spectrum component restrained,and the distribution and the frequencies of the dispersive spectra were changed.Furthermore,the pulse frequencies and intensities producing the bio-effects are discrete and distant.

Anatomy and clinical application of external malleolus periosteum bone flap pedicled with fascia and external malleolus anterior artery / 中华显微外科杂志

Objective To investigate the anatomical character and clinical application value of external malleolus periosteum bone flap pedicled with facia and external malleolus anterior artery. Methods Applied anatomy was studied with 10 adult corpse specimen after artery perfusion,observed the origin.trackway,and measured the external diameter and major vessel's length of external malleolus anterior artery,observed the composition of external malleolus artery net,and completed the performance in clinic in 10 patients and followed up for 6 months～6 years. Resultes The bone flap had abundant blood-supply,its pedicle was long enough for transfer,little injury to donor,the surgical procedure was easy to manipulate,and was used in clinic to treat talus fracture in 9 cases (fresh 5 and old 4) and old tibia fracture in 1 case,10 cases were involved with satisfactory outcome. Conclusion External malleolus periosteum bone flap pedicled with fascia and external malleolus anterior artery is a good new donor for the patients with fracture of talus or lower tibia,especially ununited case or osteonecrosis.