Biomedical subjects

Jun Wang

Publications and source records attributed to Jun Wang.

At least 595 records · Page 33Linked to original sources

PubMed2002

The inherent characteristics and DNA polymorphism of Vibrio cholerae and other vibrios.

OBJECTIVE: To investigate the inherent characteristics of Vibrio cholerae (V. cholerae) and other vibrios and their relationship. METHODS: Polymerase chain reaction (PCR), DNA sequence analysis, randomly amplified polymorphic DNA (RAPD) analysis and average linkage cluster analysis were used to study 3 isolates of V. cholerae strains O139, three isolates O1 biotype El Tor, four isolates O1 biotype classical and 3 other vibrios. RESULTS: V. cholerae O139 contained the genomic sequences of ctx A2-B as well as V. cholerae O1. V. cholerae and others vibrios were divided into 4 groups by fingerprint patterns of RAPD, that is (1) V. cholerae O139 and V. cholerae O1 El Tor; (2) V. cholerae O1 classical; (3) V. paraheamolyticus and V. vulnificus and (4) V. flluvialis. V. cholerae O139 DNA fingerprint of RAPD was consistent with the El Tor biotype: average linkage cluster distance was 0, and slightly different from the classical biotype, with a distance of 2.07. It was much more different from vibrio paraheamolyticus and others, with a distance of 6.76 - 8.54. CONCLUSION: V. cholerae and other vibrios are polymorphic in inherent characteristics. The inherent characteristics of V. cholerae O139 are the same as El Tor biotype. O139 may have evolved from the El Tor biotype. The inherent characteristics of vibrio paraheamolyticus are the same as vibrio vulnificus.

DNA, Bacterial↗

PubMed2002

[Ecological effect of pendimethalin on soil microbe].

The effect of pendimethalin, a herbicide, on microbial activity in soil was studied here. The results showed that the amount of emission CO2 from three treatment of 1, 5 and 10 micrograms.g-1 of pendimethalin had no significant differences from the CK. The study of the influences on the degradation of the cellulose demonstrated that pendimethalin can stimulate the cellulose degradation in the soil. In contrast to the CK, the half-life (T0.5) of 5, 10 micrograms.g-1 treatments were increased to 1.32 times and 2.14 times, respectively. The activities of dehydrogenase were activated in some degrees, and the higher the pendimethalin concentration the greater and longer the influence. The results also showed that the soil urease activity was restrained, and then, was stimulated by pendimethalin. The level and the sustained time of inhibition and stimulation was proportional to the concentration of the treatment.

Aniline Compounds↗

PubMed2002

[Nested coamplification polymerase chain reaction].

OBJECTIVE: To develop a simple and reliable method for intensifying the hybridization signals of gene chips. METHODS: The authors added EDTA and another FAM-labeled probe to the normal PCR products, denatured the mixture by heat, and then let the mixture hybridize with the fastened probes on the chip. RESULTS: With the use of EDTA and another FAM-labeled probe, the hybridization signals increased by 6 times or greater. CONCLUSION: Adding EDTA and another probe to the normal PCR products is a simple and efficient method to intensify the hybridization signal of chips.

Base Sequence↗

PubMed2002

[Rapid induction of mRNAs for liver regeneration genes by hepatopoietin and partial hepatectomy].

OBJECTIVE: To investigate the effect of recombinant human hepatopoietin (rhHPO) and partial hepatectomy on rapidly induced expression of immediate early gene. METHODS: We investigated the different gene expression within 1 hour after 2/3 partial hepatectomy by representational difference analysis and in primary cultured hepatocytes system. RESULTS: In the expressed sequence tag (EST) library, we identified that most of these genes were immediate early gene, and found one new gene PC3 that might be associated to liver regeneration in the EST library. Moreover, PC3 gene was rapidly induced after 2/3 partial hepatectomy and the expressing peak was within 1~2 hours after operation. HPO can rapidly induce the expression of these genes (c-fos, LRF-1, and PC3, etc.) in primarily cultured rat hepatocyte, which might be one of HPO molecular mechanism on stimulating hepatocyte proliferation. CONCLUSIONS: rhHPO and partial hepatectomy can rapidly induce the expression of immediate early gene. PC3 gene is immediate early gene related to liver regeneration.

Animals↗

PubMed2002

[Studies on production, purification and partial characteristics of the extracellular laccase from Armilliria mellea].

The production conditions of extracellular laccase from Armilliria mellea and the characteristics of the enzyme were studied. The experiment proved that initial pH5.5 of the culture medium and temperature at 25 degrees C were favorable for laccase synthesis. As carbon resources, cellobiose and raffinose were better in terms of productivity than maltose, sorbose and galactose. Organic nitrogen source was more suitable for Armilliria mellea to synthesize laccase than inorganic nitrogen source. Peat extract (PE) enhanced notably the yield of laccase; the maximal yield was 7 times as much as that of the control when PE concentration was 50%. Three isozymes were detected in culture supernatant named A, B and C respectively after their mobility on PAGE. After concentrated by (NH4)2SO4 precipitation, laccase A was further purified to homogeneity by preparative native PAGE and anion exchange column chromatography. The native enzyme was a single polypeptide with a molecular mass of approximately 59 kD estimated by SDS-PAGE, while 58 kD by gel filtration chromatography under non-denaturing conditions. Determined by IEF its isoelectric point was 4.0. The optimal pH value and temperature were 5.6 and 60 degrees C respectively in catalytic reaction of oxidizing guaiacol. At 60 degrees C and 65 degrees C, half-lives of laccase A were 45 min and 36.8 min, respectively. Enzyme activity was inhibited with 100 mmol/L Cl-, but was activated with 1 mmol/L SO4(2-). However, if the concentration of NaN3 was only 1 mmol/L, laccase A lost its activity completely. 10 mmol/L EDTA had no effect on laccase A, while 1 mmol/L Cu2+ could enhance its activity. Laccase A showed a good stability when the pH of the buffer varied from 5.2 to 7.2. Using guaiacol as the substrate, the Km was 1.026 mmol/L and the Vmax was 5 mumol/(min.mg); using ABTS instead, the Km was 0.22 mmol/L and Vmax was 69 mumol/(min.mg).

Agaricales↗

PubMed2002

[Effects of hypoxia on AChE and NADPH-d levels in the marginal division and learning and memory functions of rats].

OBJECTIVE: To observe the pathological changes and changes in acetylcholinesterase (AChE) and reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) levels in the marginal division (MrD) following hypoxia, and explore the relation of hypoxia to damages of learning and memory functions. METHODS: Hypoxia models were established in 40 SD rats by treatment with the mixture of 8% oxygen and 92% nitrogen 5 times daily for 5 consecutive days, and the sham-hypoxia group was constituted by 10 rats receiving normal oxygen supply in the same manner as above. Another 10 untreated rats were used as normal control. The rats completing the hypoxia induction procedures were subjected to Y-maze test before their brain sections, along with those of the rats in the other 2 groups, were prepared for HE staining and immunohistochemical staining. RESULTS: AChE immunohistochemical results of the normal control group revealed numerous AChE-positive fibers and some positive cells in the striatum where the MrD was more lightly stained than the other regions. In the rats with hypoxia, however, the MrD was more intensely stained in comparison with the control, but the stain in other regions of the striatum did not manifest any significant differences between the groups. The MrD of normal rats possessed more NADPH-d-positive cells, all spindle-shaped, than the other regions of the striatum, and hypoxia did not result in morphological changes of the cells but significant reduction of their quantity occurred. CONCLUSION: Hypoxia may cause reduction of the learning and memory functions of rats and gives rise to alterations of AChE and NADPH-d staining patterns in the MrD. The MrD is more vulnerable to hypoxia as evidenced by more obvious changes in AChE and NADPH-d staining in the MrD than in the other regions of the striatum, which may be associated with the impairment of the learning and memory functions by hypoxia.

Acetylcholinesterase↗

PubMed2002

[Effects of kainic acid that damages the marginal division of rat striatum on hippocampal long-term potentiation].

OBJECTIVE: To investigate the relationship between the marginal division (MrD) of the striatum and other brain regions associated with learning and memory. METHODS: Long-term potentiation (LTP) was induced by high-frequency stimulation of the perforant path-dentate gyrus, and changes in hippocampal LTP after destruction of the marginal division with kainic acid were observed. RESULTS: High-frequency stimulation of the perforant path produced significant increases in the peak amplitudes of the population spike (PS) in normal rats and those receiving saline treatment. In rats with damaged MrD, the increase in PS and the excitatory postsynaptic potential were less obvious compared with normal or saline-treated rats, indicating that the LTP of the hippocampus was attenuated by damage of the MrD. CONCLUSION: Damage of the MrD impacts the LTP formation in the hippocampus.

Animals↗

PubMed2002

[Evaluation of visual function following neodymium: YAG laser posterior capsulotomy].

OBJECTIVE: To probe into the clinical application of contrast sensitivity and glare sensitivity in evaluating visual function of posterior capsular opacification (PCO) and also investigate the visual function criterion in performing neodymium:yttrium aluminum garnet (Nd:YAG) laser posterior capsulotomy. METHODS: Measurements of visual acuity, contrast sensitivity and glare sensitivity were obtained from 73 pseudophakic eyes (67 cases) before and after Nd:YAG laser posterior capsulotomy and the results were analysed. The method of Nd:YAG laser surgery was posterior capsular circular resection. The diameter of capsular chip was 5 mm. The average energy of single pulse was (2.93 +/- 0.63) mJ and the mean total energy was (57.47 +/- 36.05) mJ. The average follow-up was (14 +/- 6) months. RESULTS: Visual acuity, contrast sensitivity curve and glare sensitivity curve improved in all cases postoperatively. Comparing the parameters of pre-laser and post-laser measurement, there was very significant difference (P < 0.01). The only postoperative complication was the laser spot in intraocular lens (IOL, 5 eyes, 6.8%). No retinal detachment, cystoid macular edema and dislocation of IOL were observed in this series. CONCLUSION: Contrast sensitivity and glare sensitivity can represent the visual function of PCO sensitively and completely. They can be regarded as evaluation criterion of surgical timing and effect of Nd:YAG laser posterior capsulotomy.

Adolescent↗

PubMed2002

[Effect of non-pulsatile blood flow on the secretion of calcitonin-gene-related peptide in patients undergoing total cavopulmonary connection].

OBJECTIVE: To study the changes of calcitonin gene-related peptide (CGRP) in patients who underwent total cavopulmonary connection (TCPC) and to assess the effects of non-pulsatile blood flow on the secretion function of the lung. METHODS: Twenty-six patients were divided into 2 groups: study group, 13 patients who underwent extracardiac TCPC, and control group, 13 patients who underwent definitive repair for ventricular septal or atrial septal defect. Blood samples for measurement of CGRP were obtained preoperatively, postoperatively or in the follow-up period. Cardiac index (CI) and pulmonary vascular resistance (PVR) were measured by cardiac catheter. RESULTS: The plasma level of CGRP was significantly higher in the study group than in the control group. CGRP was negatively correlated with PVR (r = -0.99, t = 9.82, P < 0.05), and positively correlation with CI (r = 0.98, t = 6.95, P < 0.05). CONCLUSIONS: After total right heart bypass, the non-pulsatile blood flow in pulmonary circulation may stimulate the lung to secrete CGRP, leading to the decrease of PVR and improve early postoperative recovery.

Adolescent↗

PubMed2002

[Study on hydrolysis conditions of Dioscorea nipponica with uniform design method].

OBJECTIVE: To optimize hydrolysis conditions of Dioscorea nipponica so as to provide parameters for extracting diosgenin in industry. METHODS: The optimum hydrolysis conditions were investigated using diosgenin as an index with uniform design and high performance liquid chromatography method. RESULTS: The optimum conditions were as follows: the hydrochloric acid concentration was 2.5 mol/L, solid-liquid rate was 1:5, the reaction temperature was 140 degrees C, the reaction time was 4.0 h, the mix round speed was 120 r/min. CONCLUSION: The content of diosgenin under the optimum hydrolysis conditions is raised, and the hydrochloric acid concentration should be strictly controlled because of its large influences on the results.

Dioscorea↗

PubMed2002

[Delayed rectifier K(+) channel regulated by cyclooxygenase-2 in human gastric cancer cell].

OBJECTIVE: To correlate delayed rectifier K(+) channel to cyclooxygenase-2 (COX-2) in onco genesis of human gastric cancer cell. METHODS: Human COX-2 encoding gene was cloned with RT-PCR strategy and its antisense recombinant eukaryotic expression vector was constructed. COX-2 highly expressed human gastric cancer cell line SGC7901 was stably transfected with the antisense vector. The whole-cell recording technique of perforated patch clamp was employed to observe the change of delayed rectifier K(+) current (I(k)) of SGC7901 after gene transfer or treatment with COX-2 inhibitor indomethacin. MTT was also performed to determine the effect of delayed rectifier K(+) channel inhibitors on cell growth. RESULTS: Stably transfected cell (7901-AS) was obtained and a down-regulated expression of COX-2 protein and mRNA in the cell was achieved. Patch clamp recording showed that both SGC7901 and 7901-AS cells had a typical delayed rectifier K(+) current. However, I(k) was significantly lower (P < 0.01) in transfected cell or cell treated with indomethacin at each test potential. The altered I(k) could be entirely recovered after drug removal from the cells. K(+) channel blockers tetraethylammonium (TEA) and 4-aminopyridine (4-AP) could retard the growth of SGC7901 and the transfected cell in a dose-dependent manner. CONCLUSION: Delayed rectifier K(+) channel, existing in human gastric cancer cell line SGC7901, is related to the growth of the cell. The highly expressed COX-2 may affect the biological behavior of gastric cancer cell by regulating this ion channel.

Cell Division↗

PubMed2002

[Preliminary experience of video-mediastinoscopy in clinical application].

OBJECTIVE: To determine the value of video-mediastinoscopy in clinical application. METHODS: The clinical data of 54 patients receiving video-mediastinoscopy were reviewed retrospectively. This operation consisted of cervical mediastinoscopy in 44 patients, parasternal mediastinoscopy in 6, and combined procedures in 4. Of these patients, 18 underwent video-mediastinoscopy for the evaluation of undifferentiated mediastinal disease. Thirty-six patients with suspected lung cancer showed enlarged mediastinal lymph nodes radiographically in the chest and underwent video-mediastinoscopy. RESULTS: Seventeen of 18 patients with undetermined mediastinal diseases had a definitive pathologic diagnosis, with an accuracy of 94.4% (17/18). In the 36 patients with suspected lung cancer, 22 were positive, and 14 negative. In the negative patients who underwent thoracotomy with resection, mediastinal lymph nodes revealed no evidence of metastasis. There were no postoperative complication and deaths. CONCLUSION: Video-mediastinoscopy as a highly effective and safe procedure could be used in the diagnosis and staging of thoracic diseases.

Adolescent↗

PubMed2002

[Electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases].

OBJECTIVE: To evaluate the effect of electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases. METHODS: We determined the position of lesion, separated the lesion from the esophageal wall, resected the lesion and protected the esophageal mucosa during the process of video-assisted thoracoscopic surgery for benign esophageal diseases. RESULTS: Thirty-six patients with benign esophageal disease underwent the operation successfully and recovered uneventfully. There was no operative death or severe perioperative complications such as esophago pleural fistula. Two patients were changed to undergo thoracotomy. CONCLUSIONS: Electronic fiberesophagoscopy is an essential equipment in video-assisted thoracoscopic surgery for benign esophageal diseases. It should be adopted as a routine equipment to ensure the accuracy, safety, reliability and convenience of this kind of operations.

Adolescent↗

PubMed2002

[Production of D-pantolactone hydrolase by Fusarium moniliforme SW-902].

Fusarium moniliforme SW-902, a high-yielding strain for producing D-pantolactone hydrolase was screened. The conditions for enzyme formation of the strain were studied. The suitable carbon source of the medium was glycerol and the suitable nitrogen source was peptone. The optimum temperature and initial pH for enzyme formation were 26 degrees C and pH8.0 respectively. When the organism was cultured in the 60 L-fermentor under the optimum conditions for 45 h, about 7.18 g dry cells/L and 0.92 IU/g dry cells weight were obtained.

Carboxylic Ester Hydrolases↗

PubMed2002

[Oxygen consumption and ammonia-N excretion rates of Chlamys farreri].

The oxygen consumption and ammonia-N excretion rates of Chlamys farreri were studied from April to June, 1999. The results showed that the oxygen consumption and ammonia-N excretion rates of Chlamys farreri were positively correlated with water temperature, and negatively correlated with its body weight under appropriate temperature conditions. Under the test temperature (8-28 degrees C), the oxygen consumption rate ranged from 0.48 to 9.09 mg.g-1.h-1, and the ammonia-N excretion rate ranged from 0.05 to 1.01 mg.g-1.h-1. With the raising water temperature, the oxygen consumption rate reached peak value at 23 degrees C, and began to decrease at 28 degrees C. The ammonia-N excretion rate continuously increased from 8 to 28 degrees C. The routine metabolism of Chlamys farreri under treatment was obvious higher than the standard metabolism, and the oxygen consumption and ammonia-N excretion rates increased by 35.8% and 75.9%, respectively.

Ammonia↗

PubMed2002

[Preventive and therapeutic effects of extract from Rheum palmatum on hepatic encephalopathy in rats with acute liver failure].

OBJECTIVE: To probe the preventive, therapeutic effect and the possible mechanism of extract from Rheum palmatum (ERP) on hepatic encephalopathy(HE) in rats with acute liver failure. METHODS: HE was induced by the administration of 300 mg thioracetamide per kg body weight by gavage on two consecutive days. The effects of ERP were observed on neurology test, serum ammonium, serum endotoxin and liver impairment. RESULTS: ERP could improve rat neuro-reflexes, decrease the staging of HE and rat serum ammonium, endotoxin concentrations, and reduce the liver impairment. CONCLUSION: ERP significantly prevents and treats HE in rats with thioacetamide-induced acute liver failure.

Ammonium Compounds↗

PubMed2002

[Study on voice quality after different layers injured in vocal fold with CO2 laser microsurgery].

OBJECTIVE: To investigate the nature of pathological voice after injured in different layers of vocal fold with CO2 laser microsurgery. METHOD: 50 cases of precancerous lesion (keratosis and leukoplakia) were treated with laser mucosa ablation. Glottal carcinoma (Tis-T2) were treated with laser microsurgery in mucosal stripping(30 cases) or with laser cordectomy(60 cases). Vocal function was examined by acoustic analysis (F0, Jitter, Shimmer, NNE, HNR), aerodynamic analysis (MPT, S/Z) and videostroboscopic examination. RESULT: For lesion mucosa ablation, hoarseness improved quickly after operation and acoustic analysis became normal. There were 18.2% decreased mucosa wave, 16.7% mild-moderate supraglottal hyperfunction. For mucosa stripping (cover layers excised), 63.3% decreased and 10.0% absented with mucosa wave, 46.7% mild-moderate supraglottal hyperfunction, glottal closure was incomplete. Acoustic analysis showed that Jitter, Shimmer, F0 different from normal(P < 0.05), HNR significantly different from normal(P < 0.01). For cordectomy: Acoustic analysis showed significantly worse than normal(P < 0.01), 61.7% mild-moderate supraglottal hyperfunction. The ipsilateral mucosa wave was absent, but 30.0% showed mucosa wave of vocal process and 13.3% with ventricular fold wave. There was little difference with or without vocalis muscle excision in acoustic analysis. To compared with mucosa stripping, the NNE, HNR, Jitter, Shimmer of cordectomy group was worse and amplitude was higher in cordectomy(P < 0.01). CONCLUSION: Although the acoustic characteristic and vibration mode of mucosa ablation and mucosa stripping was distinct to each other, within the cover layer injured, vocal function will be good. Once the body layer is injured, vocal quality will decrease significantly.

Adult↗

PubMed2002

[Polygraphic characteristics of upper airway resistance syndrome].

OBJECTIVE: (1) To analyze upper airway resistance syndrome (UARS) patients' polysomnographic characteristics, to lower the misdianosis of UARS. (2) To improve the understanding of UARS. METHODS: (1) Select 12 UARS patients diagnosed by PSG and continuous esophageal pressure measurement, the sleep structure, arousal index, apnea hyponea index (AHI) were analyzed, the body mass index (BMI), epworth sleepiness scale (ESS) were calculated. (2) Select 16 simple snoring cases as the control group, obstructive sleep apnea syndrome (OSAS) and UARS were ruled out by PSG and continuous esophageal pressure measurement for this group of cases. (3) Compare the 2 groups' first night PSG indexes (4) Compare the 2 nights PSG indexes of the UARS group, to see the continuous esophageal pressure measurement effects on their sleep. RESULTS: (1) There are no statistical difference of the 2 group's BMI and AHI. (2) Compared with the control group, UARS patients got higher arousal index and ESS score, more sleep stage 1 and stage 2, less sleep stage 3 and stage 4. (3) The 2 nights PSG indexes of UARS patients are not statistically different. CONCLUSIONS: (1) Compared with simple snoring cases, the UARS patients have some special characteristics, i.e., higher arousal index, less deep sleep, and higher ESS score, combined with the clinical manifestations, it is possible to screen UARS patients. (2) No evident effects of continuous esophageal pressure measurement on UARS patients sleep.

Adult↗