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Xiang Liu

Publications and source records attributed to Xiang Liu.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Relief effect of beta-galactosidase genetically engineered lactococcus lactis on the cell toxicity caused by lactose].

OBJECTIVE: To assess the relief effect of beta-galactosidase genetically engineered Lactococcus lactis on the cell toxicity caused by lactose in vitro. METHODS: An in vitro toxic Caco-2 cell model caused by lactose was established to evaluate the relief effect of beta-galactosidase genetically engineered Lactococcus lactis. Cell morphological parameters and proliferation activity parameter were used. RESULTS: The in vitro toxic Caco-2 cell model caused by lactose was successfully established; the genetically engineered Lactococcus lactis constructed in the authors' laboratory could enable the Caco-2 cell to have normal appearance with the presence of lactose and could improve the proliferation activity with the presence of high concentration of lactose (P < 0.01). CONCLUSION: The beta-galactosidase genetically engineered Lactococcus lactis has significant relief effect on the cell toxicity caused by lactose in vitro, which lays a foundation for food-grade alternation of this bacterium.

Caco-2 Cells↗
PubMed2006

[Studies of the factors linked to the bacteriostatic ability of Lactobacillus in human vagina].

OBJECTIVE: To study the factors linked to the bacteriostatic ability of Lactobacillus in human vagina, and the relationship between the Lactobacillus and the Candida albicans. METHODS: The content of H2O2, in the upper culture mediums of Lactobacilli were detected at different incubation time. Selecting the strains with vary bacteriostatic ability by Oxford cup test, detecting pH of these strains cultured after different time. After co-cultivation of the Lactobacillus, which has the strongest bacteriostatic ability, Candida albicans and Staphylococci for different incubation time, quantities of these mixed cultures were investigated. RESULTS: The date of pH and the size of the bacteriostatic ring are negative correlation. There is not obvious relationship between the ability of producing H2O2 and the bacteriostatic ability of Lactobacillus. The study of the relationship between bacteria shows that the quantity of Staphylococci is as this: Staphylococci alone > Staphylococci + Lactobacillus > Staphylococci + Lactobacillus + Candida albicans. CONCLUSION: The bacteriostatic ability of Lactobacillus is positivly related to its acid producing ability, and is not obvious to H2O2 content. After 36 hours cultivation time, Candida albicans can boost up the bacteriostatic ability of Lactobacillus.

Adult↗
PubMed2006

[Analysis of ordinal repeated measures data using generalized estimating equation].

OBJECTIVE: To explore the application of the generalized estimating equation in the ordinal repeated measures data and hence provide methodology reference for the analysis of repeated measures data in the clinical trials. METHODS: An example was illustrated by modeling generalized estimating equation using the GENMOD command in comparison with the independent logistic regression. RESULTS: All parameters and their standard error were estimated, so every factor could be dealt with intuitive estimation of parameter. The standard errors of coefficients in generalized estimating equation are generally greater than that in independent logistic regression. CONCLUSION: Generalized estimating equation can solve the correlation between the dependent data by using working correlation matrix, and it can control strata correlation, repeated measures factor and other confounding factors effectively, so generalized estimating equation provides an effective method for the ordinal repeated measures data.

Clinical Trials as Topic↗
PubMed2006

[Biodegradation of benzene series compounds under nitrate reducing conditions].

A series of batch experiments were performed using mixed bacterial culture to investigate the biodegradability of benzene, toluene, ethylbenzene and the xylene isomers (BTEX) under denitrifying conditions. The results show that BTEX can be degraded effectively by the mixed bacterial culture. The biodegradation of BTEX could be modeled by the substrate inhibition Monod equation. When the concentrations of BTEX were less than 50 mg x L(-1), the anaerobic degradation rates decreased with toluene > ethylbenzene > m-xylene > o-xylene > p-xylene > benzene. The ratio between the amount of nitrate consumed and the amount of the benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene degraded was 9.47, 9.26, 11.14, 12.46, 13.36 and 13.02, respectively. The electron acceptor needed in the initial anaerobic degradation of BTEX was nitrate, and then both nitrate and nitrite could be served as the electron acceptors for the further degradation of the intermediates of BTEX.

Bacteria, Anaerobic↗
PubMed2006

[Diagnosis and treatment on osteoradionecrosis of temporal bone in cases with nasopharyngeal carcinoma after radiotherapy].

OBJECTIVE: To discuss the diagnosis and treatment on osteoradionecrosis of temporal bone in case with nasopharyngeal carcinoma (NPC) after radiotherapy. METHOD: The clinical data of 21 cases (22 ears) diagnosed as osteoradionecrosis of temporal bone with NPC were studied, including 17 ears of localized type and 5 ears of diffuse type. Minimally surgical debridement with otoscope was performed on 17 ears of localized type and 1 ear of diffuse type. Four ears of diffuse type underwent the modified radical mastoidectomy and obliteration with vascularized fascia flaps. RESULT: The common clinical features were foul-smelling otorrhea and otalgia. Otoscopy revealed the exposed bone and bony sequestration in the external auditory canal with impacted keratotic debris, granulation tissue and cholesteatoma accumulation. It was with erosion or/and orifice to the mastoid. CT scan demonstrated the presentations: osteomyelitis, bone destruction as the islet-appearance and soft tissue mass. Among the 17 ears of localized type, 12 ears (70.6%) showed complete epithelization of the raw surface, 4 ears (23.5%) not fully epithelized were followed up without sequestration, and 1 ear (5.9%) was developing progressively. As for the 5 ears of diffuse type, 1 ear received the minimally surgical debridement and another 3 ears treated with mastoidectomy and obliteration were healed. Only 1 ear needed secondary surgery because of re-sequestration. CONCLUSION: Both otoscopy and CT scan can offer the diagnostic value with different characteristics. The minimally surgical debridement of the sequestration by otoscopy can obtain good effects on localized type. It should be careful to select the surgery recipient on the diffuse type, and mastoid obliteration with vascularized flaps from regional tissue may be warranted after mastoidectomy. Regular follow up is needed because of possibility of the progressive development of the disease.

Adult↗
PubMed2005

Dicer-1 and R3D1-L catalyze microRNA maturation in Drosophila.

In Drosophila melanogaster, Dicer-2/R2D2 and Dicer-1 generate small interfering RNA (siRNA) and microRNA (miRNA), respectively. Here we identify a novel dsRNA-binding protein, which we named R3D1-L, that forms a stable complex with Dicer-1 in vitro and in vivo. While depletion of R3D1-L by RNAi causes accumulation of precursor miRNA (pre-miRNA) in S2 cells, recombinant R3D1-L enhances miRNA production by Dicer-1 in vitro. Furthermore, R3D1 deficiency causes miRNA-generating defect and severe sterility in male and female flies. Therefore, R3D1-L functions in concert with Dicer-1 in miRNA biogenesis and is required for reproductive development in Drosophila.

Adenosine Triphosphate↗
PubMed2005

Synthesis and in vivo evaluation of a new PET radioligand for studying sigma-2 receptors.

The cyclohexyl piperazine 1 (1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydro-naphthalen-1-yl)-propyl]-piperazine) has been shown to be a potent and selective sigma-2 receptor ligand. In the present study, we prepared [(11)C]1 by O-alkylation of the phenolic precursor 2 with [(11)C]CH(3)I. [(11)C]1 was obtained in a 29% non-decay corrected yield and specific activity of 9299 mCi/micromol calculated at end-of-synthesis. The biodistribution of [(11)C]1 in mouse brain demonstrated rapid and homogenous concentration in all brain structures, which included the cortex, thalamus, cerebellum and striatum. Co-administration of unlabelled 1 (1 mg/kg) or the sigma-2 selective ligand SM-21 (1 mg/kg) failed to show any significant inhibition of [(11)C]1 uptake in the mouse brain. The evaluation of this radioligand in vivo in the mouse clearly indicates that it does not possess the required properties for studying sigma-2 receptors in the brain using PET.

Animals↗
PubMed2005

Tibial torsion measurement by surface curvature.

BACKGROUND: Tibial torsion is the angle between the transverse axes of the proximal and distal tibial articular surfaces. It measures the degree of twisting of the tibia around its own longitudinal axis. The accurate measurement on the magnitude of tibial torsion is of great use in monitoring derangements. It is also useful as a baseline in the event of surgical intervention. Various methods have been developed but none of them have gained wide acceptance. Even the CT scan technique, which is considered the "gold standard", produces varying results when executed by different researchers. A quick, objective and non-invasive method is thus very much needed for the effective monitoring of tibial torsion in clinical environments. METHODS: Eighteen adult men's lower legs were scanned by a laser scanner to give the surface coordinates of the leg surfaces. By calculating curvature maps of legs from the 3D coordinates, stable anatomical landmarks such as the lateral and medial malleoli can be located. The angle indicating the degree of tibial torsion can then be derived from these landmarks. FINDINGS: The objective determination of the various anatomical landmarks results in a reproducible measure of tibial torsion. The results obtained in this study are generally in agreement with the measurements reported previously. INTERPRETATION: The reproducibility of the results allows for the objective observation, monitoring and comparison of tibial torsion over time and across subjects. It allows also for the development of a system of measurement that is fast, convenient, accurate and radiation-free.

Bone Diseases↗
PubMed2005

Cloning and characterization of chymotrypsin- and trypsin-like cDNAs from the gut of the Hessian fly [Mayetiola destructor (Say)].

Fifteen unique cDNA clones encoding trypsin- or chymotrypsin-like proteins were cloned and characterized from a gut cDNA library derived from Hessian fly [Mayetiola destructor (Say)] larvae. Based on sequence similarities, the cDNAs were sorted into five gene groups, which were named MDP1 to MDP5. Two of the gene groups, MDP1 and MDP2, encoded chymotrypsin-like proteins; the other three encoded putative trypsins. All deduced proteins have conserved His(87), Asp(136), and Ser(241) residues for the catalytic triad and three pairs of cysteine residues for disulfide bridge configurations. The substrate specificity determination residue at position 235 was also conserved in the putative trypsins and chymotrypsins. In addition, all the deduced protein precursors had a typical secretion signal peptide and activation peptide. Northern blot analysis revealed that all these gene groups were exclusively expressed in the larval stage. The expression profiles for each gene group differed significantly in different ages of the larva, as well as in different tissues. Protease activity analysis of gut extract, using specific inhibitors, demonstrated that serine proteases were the major digestive enzymes in the gut of M. destructor larvae. Serine protease inhibitors inhibited as much as 90% proteolytic activities of gut extract, whereas inhibitors specific to other proteases, including cysteine proteases, aspartic proteases, and metallo-proteases, inhibited only 10-24% of gut protease activity.

Amino Acid Sequence↗
PubMed2005

Influence of trishomocubanes on sigma receptor binding of N-(1-benzyl-piperidin-4-yl)-4-[123I]iodobenzamide in vivo in the rat brain.

Three new trishomocubane analogues based on the 4-azahexacyclo[5.4.1.0(2,6).0(3,10).0(5,9).0(8,11)] dodecane-3-ol skeleton have been synthesised and assessed for their affinities at both sigma-1 and sigma-2 receptors. The effect of various N-substitution on the polycyclic moiety was examined. All synthesised compounds displayed high affinity for sigma-1 receptors (9-10 nM) and good affinity for sigma-2 receptors (230-310 nM), suggesting that substitution at the nitrogen moiety of the trishomocubane is well tolerated and represents a platform for the development of improved higher affinity sigma receptor ligands. The interaction of these functionalised trishomocubanes on the binding of the known sigma receptor radioligand, 4-[123I]IBP, was evaluated in the rat brain. Although 4-[123I]IBP had been used for imaging sigma receptors in tumours, this is the first examination of sigma receptor binding in the rat brain and therefore the potential of 4-[123I]IBP for imaging the brain was also evaluated. In vivo specificity and selectivity of 4-[123I]IBP binding was examined by studying the effects of pre-administration of sigma receptor binding drugs (+)-pentazocine and unlabelled 4-IBP. This resulted in a blockade of only 42% of 4-[123I]IBP uptake in the brain indicating high degree of non-specific binding suggesting that it may not be suitable for imaging sigma receptors in the brain. The inhibition of 4-[123I]IBP uptake using the two of the three trishomocubanes displayed a consistent blockade of 48-30% in all brain structures. This demonstrates for the first time the ability of functionalised trishomocubanes to interact with sigma receptors in vivo.

Animals↗
PubMed2005

[Over one hundred year sedimentary record of polycyclic aromatic hydrocarbons in the Pearl River Estuary, South China].

The western shoal of the Lingding Bay is known to be an important deposition zone of terrestrial substance in the Pearl River Estuary (PRE). In this study, the vertical variations of concentration and fluxes of polycyclic aromatic hydrocarbon (PAH) are investigated in a core from the west shoal of Lingding Bay. In combining with 210Pb-dating, the PAHs sedimentary record in the last 100 years is reconstructed. The sigmaPAH concentration ranged from 59 ng x g(-1) to 330 ng x g(-1) throughout the core with two distinct peaks. An initial increase in sigmaPAH concentration was found around the 1860s, followed with the first maximum in the 1950s. There was a decrease in total PAHs concentration and flux in 1960s and 1970s. A sharp increase in PAHs levels was observed from 1980s and a maximum was found in the 1990s. PAHs diagnostic ratios indicate that PAH in the sediment core are mainly of pyrolytic origin. PAHs concentrations are found to correlate positively with the Gross Domestic Production, vehicle numbers and power generation in the surrounding regions, indicating that the PAHs in the sediment core are mainly anthropogenic. Atmospheric deposition and land runoff may serve as the important pathway of PAHs input to the sediment.

China↗
PubMed2005

[The significance of IFN-gamma measurement in middle ear effusion of secretory otitis media].

OBJECTIVE: To explore the clinical significance of IFN-gamma in secretory otitis media (SOM) by measuring and analyzing and the level of INF-gamma in the effusion of middle ear. METHOD: A commercially available enzyme-linked immunosorbent assay (ELISA) incorporating a biotinylated monoclonal antibody probe was utilized for the quantitative measurement of IFN-gamma in the middle ear effusion and serum samples of the patients and that of the normal persons. RESULT: The level of IFN-gamma in the middle ear effusion was much higher than that in the serum samples. The difference of the level of IFN-gamma in the serum samples is not significant between the test group and the control group. The level of IFN-gamma in chronic period was much higher that in acute period. The level of IFN-gamma in the middle ear effusion has no significant difference between the group undergoing tympanocentesis for the first time and the group undergoing tympanocentesis for the second time (P > 0.05). The levels of IFN-gamma in the middle ear effusion in the group undergoing tympanocentesis for three or more times arose obviously (P < 0.01). CONCLUSION: The IFN-gamma in the middle ear effusion may be produced by local tympanum,but not exuded simply from blood. The high expression of IFN-gamma in the middle ear effusion may be a reference of SOM tending to chronic course.

Adolescent↗
PubMed2005

[Clinical application of osseointegration for auricular defects and deformity].

OBJECTIVE: To investigate the clinical value of osseointegration for repairing auricular defects and deformity. METHODS: Twenty cases (21 ears) including congenital and non-congenital auricular defects and deformity, were treated with osseointegrated prostheses according to the manual of Branemark implanting system. The first-stage operation was for osseointegration of implants, and the second-stage was for anchoring the prostheses. All cases were followed up for six months to three years. RESULTS: One-time success rate is 100%. Satisfactory rate of appearance recovery is 90.47%. The infection rate between osseointegrated implants and surrounding tissue is 14.28%. The stability rate of prostheses is 100%. CONCLUSIONS: It has a good result to apply osseointegrated prostheses for repairing auricular defects and deformity.

Adolescent↗
PubMed2005

[Clinical manifestation of attic retraction pocket].

OBJECTIVE: To analyze the clinical manifestation of attic retraction pocket. METHOD: Ninety-two patients with 118 involved ears were studied. The clinical data including clinical manifestation, endoscopic findings and gradings,hearing tests, imaging findings and accompanying lesions. RESULT: According to Tos's grades, 15 ears (14/118,12.7%) belonged to stage I, 48 (42/118, 40.7%) belonged to stage II, 23 (23/104,19.5%) belonged to stage III and 32 (32/118, 27.1%) belonged to stage IV. Patients always complained of ear blockage,hearing loss and tinnitus. Accompanying lesions including otitis media with effusion, middle ear atelectasis, adhesive otitis media and retraction pocket cholesteatoma could be found by endoscopy. The results of pure audiometry were related to the grades of lesions. Most patients had conductive hearing loss and a few patients had mixed hearing loss. The tympanometry in most cases was type B or C. Imaging examination (CT or X-ray) of 97 ears showed poor pneumatization of mastoids and there was a significant difference between involved group and control group (P < 0.01). CONCLUSION: The attic retraction pocket reflected the negative pressure of middle ear and its pathogenesis was related with the function of Eustachian tube, inflammation and pneumatization of mastoid. Since it had a risk to develop into retraction pocket cholesteatoma, following-up and interferon to early or middle stage lesion should be paid more attention.

Adolescent↗
PubMed2005

[Clinical classification and treatment of localized attic cholesteatoma].

OBJECTIVE: To investigate the clinical classification and treatment of localized attic cholesteatoma through surgical management. METHOD: Twenty-one patients (21 ears) of localized attic cholesteatoma accepted atticotomy. Then different surgical managements were carried out according to the extent of cholesteatoma and whether the malleo-incudal joint was destroyed or not. If the cholesteatoma has only reached the surface of the malleo-incudal joint, it was regarded as type I (5 patients). To this type, the cholesteatoma was removed and the ossicular chain was preserved. If the cholesteatoma has entered the anterior attic space and destroyed the malleo-incudal joint, it was regarded as type II (16 patients). Besides the removing of cholesteatoma, the head of malleus and incus should be removed also in this condition. Then reconstruction of the ossicular chain was performed by putting PORP artificial auditory ossicles between the manubrium mallei and staple. In all these 21 patients, the lateral wall of attic was reconstructed with the cartilage of tragus. The perichondrium of the cartilage was used to repair the perforation in the non-vibrant membrane. Healing of the lateral wall of attic and the tympanic membrane and recovery of hearing level were investigated after the operation. RESULT: The follow-up period lasted 1 year to 5 years. Healing of the lateral wall of attic and the tympanic membrane were satisfying in all 21 patients. According to the pure tone audiometry after the operation, A-B gap was less than 10 decibel in 10 patients,less than 20 decibel in 7 patients, less than 30 decibel in 3 patients, and over 30 decibel in only 1 patient. Acoustic transmission function was preserved or reconstructed. No vertigo or tinnitus happened after operation. CONCLUSION: Diagnosis of localized attic cholesteatoma should be made early. If it can be treated by clinical classification properly, not only the removing of cholesteatoma, but also the reservation and recovery of acoustic transmission function can be obtained. It is worthy of further discussion.

Adolescent↗
PubMed2005

[Value of the different positioning tests in diagnosis of benign paroxysmal positional vertigo].

OBJECTIVE: To ascertain the value of different positioning tests in diagnosis of benign paroxysmal positional vertigo (BPPV). METHOD: Seventy-two patients who had determined the diagnosis of the posterior semicircular canal BPPV (PC-BPPV) in our department from Feb. 2000 to Apr. 2004 was tested with different positioning maneuvers. All cases were randomly divided into 2 groups with cross-over design. Group A with 36 subjects was tested with the Dix-Hallpike maneuver followed up by side-lying maneuver; Group B was tested in reverse order. Then, the Roll test was performed. RESULT: The results had association (P > 0.01) between the Dix-Hallpike maneuver and side-lying maneuver, and the positive rate had no significant difference (P < 0.01). The features of vertigo and nystagmus provoked by the tests were the same. One patient was found combining with BPPV of horizontal semicircular canal (HC-BPPV) by the Roll test. CONCLUSION: As the Dix-Hallpike maneuver, the side-lying test has the same diagnostic value in determine the PC-BPPV. Because it is safer and easier to perform in the condition of range-of-motion limitations such as spondylosis, it can alter the Dix-Hallpike maneuver. If the horizontal nystagmus provoked in above tests, the Roll test should be perform also to determine whether combining with HC- BPPV or not.

Adult↗