Biomedical subjects

Wei Liu

Publications and source records attributed to Wei Liu.

At least 271 records · Page 15Linked to original sources

PubMed2005

Use of autologous tissue engineered skin to treat porcine full-thickness skin defects.

OBJECTIVE: To explore a feasible method to repair full-thickness skin defects utilizing tissue engineered techniques. METHODS: The Changfeng hybrid swines were used and the skin specimens were cut from the posterior limb girdle region, from which the keratinocytes and fibroblasts were isolated and harvested by trypsin, EDTA, and type II collagenase. The cells were seeded in Petri dishes for primary culture. When the cells were in logarithmic growth phase, they were treated with trypsin to separate them from the floor of the tissue culture dishes. A biodegradable material, Pluronic F-127, was prefabricated and mixed with these cells, and then the cell-Pluronic compounds were seeded evenly into a polyglycolic acid (PGA). Then the constructs were replanted to the autologous animals to repair the full-thickness skin defects. Histology and immunohistochemistry of the neotissue were observed in 1, 2, 4, and 8 postoperative weeks. RESULTS: The cell-Pluronic F-127-PGA compounds repaired autologous full-thickness skin defects 1 week after implantation. Histologically, the tissue engineered skin was similar to the normal skin with stratified epidermis overlying a moderately thick collageneous dermis. Three of the structural proteins in the epidermal basement membrane zone, type IV collagen, laminin, and type VII collagen were detected using immunohistochemical methods. CONCLUSIONS: By studying the histology and immunohistochemistry of the neotissue, the bioengineered skin graft holds great promise for improving healing of the skin defects.

Animals↗

PubMed2005

[Investigation on oral lesions in 64 Chinese HIV/AIDS patients in Guangxi province].

OBJECTIVE: To investigate the prevalence, age and gender distribution and clinical features of HIV/AIDS oral lesions in patients in Guangxi province, and to provide the epidemiological information for prevention and treatment of these diseases in the certain population. METHODS: A total of 64 HIV/AIDS patients were included in this study. All patients HIV serum-status was confirmed in Guangxi Center of Disease Control (GXCDC). Oral examination was carried out by standardized specialists. HIV/AIDS orofacial lesions were recorded and diagnosed using the EC Clearing House Criteria on Oral Problems related to HIV Infection (1992). RESULTS: Among the total of 64 HIV/AIDS patients included in this study, there were 53 males and 11 females, with mean age of 36.1 years. Candidiasis was the most common lesion with the pseudomembranous type predominating. High prevalences of xerostomia, 11 oral ulceration and 7 HIV related periodontitis were noted. 6 Herpetic stomatitis and 3 herpes zoster, 2 oral hairy leukoplakia and 1 Kaposi's sarcoma and 1 lymphadentitis also were found. CONCLUSION: This study shows a high prevalence of candidiasis, salivary gland disease. Maybe oral ulceration prevalence is not increased, but lesion severity is increased with more severe heperiform or major RAU. It suggested that HIV/AIDS usually shows oral lesion and partly can appear in early phase.

Acquired Immunodeficiency Syndrome↗

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

[Experimental study of pilots' scan and performance, workloads].

OBJECTIVE: To study the problems of pilots' scan, performance, workload. METHOD: An experimental system for evaluating pilots' scan, performance, workload was built up based on previous studies. RESULT: After theoretical consideration and analysis of experimental results, the difference between expert pilots and novice pilots were disclosed preliminarily. CONCLUSION: Expert pilots demonstrates more frequent fixations with shorter dwell time than novice pilots do; to both pilots, the conclusion can be drawn that the variation between workloads and performance is not fixed.

Aerospace Medicine↗

PubMed2005

[Construction and clinical application of tissue engineered epidermal membrane].

OBJECTIVE: To Construct tissue engineered epidermal membrane for promoting healing of clinical skin graft donor site wound. METHODS: Epidermal cells /Chitosan-Gelatin (CG) membrane was constructed with cultured human epidermal cells(EC) and CG membrane, at the donor site of split skin graft, the wound was divided into three groups: the control group was covered with CG membrane without KC, KC/CG membrane was grafted on the treatment part of the wound area, and blank group was covered with traditional vaseline gauze. The engineered epidermal membrane and its effect on wound were evaluated with gross observation, HE, immunohistochemistry, collagen type I/III ratio by picrosirius polarization method and RT - PCR test at various time points before and after operation. RESULTS: The result showed that human tissue engineered epidermis could be constructed with cultured human EC and CG membrane, and this artificial epidermal membrane could be used for promoting the healing of skin graft donor site wound successfully (16 cases with 3 months' oberservation). The average healing time is (16.2 +/- 3.8) days for control group, (8.1 +/- 1.3) days for experimental group and (23.0 +/- 5.7) days for blank group. The artificial epidermis was well survived with normal structure. In addition, less hypertrophic scar development was observed in treated wound at 90 days (3 in 16 cases, 20.0%) than in the blank sites (11 in 16 cases, 74.4%). The difference is statistically significant (chi2 = 8.127, P < 0.01). CONCLUSIONS: The constructed EC-CG membrane can be constructed in vitro, survived in vivo and has good clinical application in promoting healing of skin graft donor site wound and inhibiting hypertrophic scar formation.

Adult↗

PubMed2005

[Observation on therapeutic effect of acupuncture and moxibustion in 60 cases of Sjogren syndrome].

OBJECTIVE: To observe clinical therapeutic effect of acupuncture on Sjogren syndrome. METHODS: Treatment group (n=60) were treated with acupuncture of clearing away dryness and toxic substance and removing obstruction in collaterals at Quze (PC 3), Taichong (LR 3), Xuehai (SP 10), Sanyinjiao (SP 6) and Taixi (KI 3), and the control group (n=60) with prednisone. Their therapeutic effects were compared. RESULTS: The total effective rate was 73.3% in the treatment group and 56.7% in the control group with a significant difference between the two groups (P < 0.05); there was no reverse effect in the treatment group. CONCLUSION: The needling method for clearing dryness and removing obstruction in collaterals is effective and safe for treatment of Sjogren syndrome.

Acupuncture↗

PubMed2005

[Experimental study on conduction of Gong tonality vibromusic sound wave in the healthy human body].

OBJECTIVE: To study the conduction of Gong tonality vibromusic sound wave along meridians in healthy human body, and investigate differences of the sensitivity of different meridians and genders to this vibromusic message. METHODS: Emit the Gong tonality music signal under the water and then investigate the responses of different acupoints and control points at the tissue of the same level to the vibromusic sound wave. RESULTS: There were differences of sensitivity to music waves at source acupoints on the foot, sensitivity of Zusanli (ST 36) was significantly higher than its control point (P < 0.05), and there was difference between genders in the sensitivity of Sanyinjiao (SP 6) and Yinlingquan (SP 9) to music sound wave. CONCLUSION: Gong tonality vibromusic sound wave can conduct along meridians in healthy human body, and there are differences between different meridians and different genders in the sensitivity to the music sound wave.

Acupuncture Points↗

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

[Studies on the changes of 5-hydroxymethyl furfuraldehyde content in Radix Rehmanniae steamed for different time].

OBJECTIVE: To find the changing regularity of 5-Hydroxymethyl furfuraldehyde (5-HMF) content in Radix Rehmanniae steamed for different time. METHOD: HPLC method was used, with C18 column (6 mm x 200 mm, 5 microm), a mixture of methanol-water (15: 85) as the mobile phase. The flow rate was 1.0 mL x min(-1). The UV detection was setat 284 nm and the column temperature was set at 24 degrees C. RESULT: The linear range was from 0.01 to 0.08 microg, r = 0.999 9 (n = 5). The average recovery was 100.2% and RSD was 2.7% (n = 5). CONCLUSION: The 5-HMF content increases as the processing time prolongs in a certain time rang.

Chromatography, High Pressure Liquid↗

PubMed2005

[A case-control study on the mxA polymorphisms and susceptibility to severe acute respiratory syndromes].

OBJECTIVE: To investigate the association between the genetic polymorphisms of myxovirus resistance 1 (MxA) gene and susceptibility to severe acute respiratory syndromes (SARS). METHODS: A case-control study was conducted and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect the T/G polymorphism at position-88 in the mxA gene promoter. Information on related factors of SARS was collected using a pre-testing questionnaire. Univariate and multivariate logistic analyses were conducted with SPSS software package. RESULTS: Sixty-six cases and sixty-four controls were selected for the study. Comparing with GG genotype, the proportion of GT genotype were significantly higher in the case group (81.3%) than that in the control group (62.5%)) with an OR (95% CI) of 2.700 (1.208-6.037). Multivariate logistic regression analysis revealed that the significant association remained after factors as wearing masks, protection gowns and eye-protection when contacting with SARS patient etc. were adjusted with an OR (95 % CI) of 2.911 (1.027-8.250). CONCLUSION: mxA promoter-88G/T SNP might be confered to host genetic susceptibility to SARS in Chinese Han population.

Adult↗

PubMed2005

[Effects of returning maize straw into field on dynamic change of soil microbial biomass C, N and P under different promoted decay condition].

A 2-year field experiment of wheat-maize rotation was conducted on a cinnamon soil of east Hebei Province to study the effects of returning maize straw into field on the dynamics of soil microbial biomass C, N and P, and their relationships with soil nutrients and enzyme activities. The results showed that under the condition of returning maize straw combined with applying chemical fertilizer to adjust straw C/N, the application of effective microorganisms could increase soil microbial biomass C, N and P in each crop growth period, advance their peak time, and better regulate soil nutrient supply, compared with no application of effective microorganisms. Soil microbial biomass had a significantly positive correlation with soil enzyme activities, but its correlation with soil hydrolysable N and available P was strongly affected by crop growth and fertilization system.

Carbon↗

PubMed2005

[Enzymatic degradation of organophosphorus insecticide chlorpyrifos by fungus WZ-I].

Degradation characteristics of chlorpyrifos insecticides was determined by the crude enzyme extracted from the isolated strain WZ-I ( Fusarium LK. ex Fx). The best separating condition and the degrading characteristic of chlorpyrifos were studied. Rate of degradation for chlorpyrifos by its intracellular enzyme, extracellular enzyme and cell fragment was 60.8%, 11.3% and 48%, respectively. The degrading enzyme was extracted after this fungus was incubated for 8 generations in the condition of noninducement, and its enzymic activity lost less, the results show that this enzyme is an intracellular and connatural enzyme. The solubility protein of the crude enzyme was determined with Albumin (bovine serum) as standard protein and the solubility protein of the crude enzyme was 3.36 mg x mL(-1). The pH optimum for crude enzyme was 6.8 for enzymatic degradation of chlorpyrifos, and it had comparatively high activity in the range of pH 6.0 - 9.0. The optimum temperature for enzymatic activity was at 40 degrees C, it still had comparatively high activity in the range of temperature 20-50 degrees C, the activity of enzyme rapidly reduced at 55 degrees C, its activity was 41% of the maximal activity. The crude enzyme showed Km value for chlorpyrifos of 1.049 26 mmol x L(-1), and the maximal enzymatic degradation rate was 0.253 5 micromol x (mg x min)(-1). Additional experimental evidence suggests that the enzyme had the stability of endure for temperature and pH, the crude enzyme of fungus WZ-I could effectively degrade chlorpyrifos.

Biodegradation, Environmental↗

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↗

PubMed2004

[The effect of intraoperative continuous nimodipine infusion on cerebral vasospasm during intracranial aneurysm surgery].

OBJECTIVE: To evaluate the effect of intraoperative continuous nimodipine infusion on cerebral vasospasm during intracranial aneurysm surgery. METHODS: Thirty consecutive patients under-going intracranial aneurysmal surgery were prospectively randomized into two groups: Isoflurane (group A, n = 15) and nimodipine (group B, n = 15). The patients in group A were maintained with 1 minimum alveolar concentration (MAC) isoflurane anesthesia during the whole procedure. The patients in group B were given nimodipine infusion continuously (20 microg.kg(-1).h(-1)) after induction of anesthesia and anesthetized with 1 MAC isoflurane. S100B levels in cerebrospinal fluid were determined before aneurysm clipping and 0, 2, 4 h after aneurysm clipping by enzyme linked immunosorbent assay. Assessment of mean blood flow velocity of parent arterial and arterial branches were performed before and after aneurysm clipping. RESULTS: (1) S100B in cerebrospinal fluid was increased significantly at 4 h after aneurysm was clipped in group A (F = 4.11, P < 0.05). However, S100B in cerebrospinal fluid was stable in group B in the whole procedure. (2) Mean arterial flow velocity of parent vessels in group B was lower significantly than that in group A (t = 2.08, P < 0.05). However, mean arterial flow velocity of distal vessels in both groups has no significant difference. CONCLUSION: Intraoperative nimodipine infusion may prevent cerebral vasospasm during intracranial aneurysm surgery.

Adult↗

PubMed2004

Bmp4 in limb bud mesoderm regulates digit pattern by controlling AER development.

In the developing limb, Bmp4 is expressed in the apical ectodermal ridge (AER) and underlying mesoderm. Insight into the function of Bmp4 in limb development has been hampered by the early embryonic lethality of Bmp4 null embryos. We directly investigated Bmp4 using a conditional null allele of Bmp4 and the Prx1(cre) transgene to inactivate Bmp4 in limb bud mesoderm. The limb bud mesoderm of Prx1(cre);Bmp4 mutants was defective in production of Bmp4 but still competent to respond to Bmp signaling. Prx1(cre);Bmp4 mutant embryos had defective digit patterning including hindlimb preaxial polydactyly with posterior digit transformations. The Prx1(cre);Bmp4 mutants also had postaxial polydactyly with digit five duplications. Bmp4 mutant limbs had delayed induction and maturation of the AER that resulted in expanded Shh signaling. Moreover, the AER persisted longer in the Bmp4 mutant limb buds exposing the forming digits to prolonged Fgf8 signaling. Our data show that Bmp4 in limb mesoderm regulates AER induction and maturation and implicate signaling from the AER in regulation of digit number and identity.

Animals↗

PubMed2004

[Influence of mechanical stress on chondrogenesis of in vitro cultured porcine bone marrow stem cells: a preliminary study].

OBJECTIVE: To evaluate the influence of mechanical stress on chondrogenesis of in vitro cultured porcine bone marrow stem cells (BMSC). METHODS: Porcine BMSC of passage 2 were seeded onto a cylinder-shaped PGA/PLA scaffold, 8mm in diameter and 3mm in thickness, at a density of 5 x 10(7)/cm(3). After the cell-scaffold constructs were cultured for one week, the primary medium, high-glucose DMEM medium with 10% fetal bovine serum (FBS), was replaced by chondrogenically inductive medium containing TGFbeta(1) (10 ng/ml), IGF-I (50 ng/ml), and dexamethasone (40 ng/ml) in addition to DMEM+10% FBS. The constructs were randomly divided into three groups according to the imposed stress: experimental group A in which a centrifugal stress was imposed at 100 g, 30 min, 2/d; experimental group B in which a rotative stress was imposed at 80 rpm, 8 h/d by a shaker; and control group in which the constructs were statically cultured. The gross view, histology, histochemistry, immunohistochemistry and glycosaminoglycan (GAG) content were evaluated after 4 and 8 weeks respectively. RESULTS: Four weeks later, the constructs in both experimental groups maintained their original sizes and shapes. Histology showed nodular lacuna-like structures, in company with GAG deposition and collagen synthesis. In addition, collagen type II was detected by immunohistochemistry. In the control group, however, the constructs shrunk to a little smaller size than those in the experimental groups, and histological staining showed a little amount of lacuna. Eight weeks later, the constructs in both experimental groups still maintained the original sizes and shapes with good elasticity. HE staining showed massive lacuna-like structures in most areas of the construct and extracellular matrix deposited evenly. Fibrous tissues were only observed in some areas. Safranin-O staining showed massive GAG formation and Masson staining showed much more collagen formation than those in the control group. Immunohistochemical staining of collagen type II showed strong positive expression. In the control group the constructs showed massive fibrous tissues, with a small amount of lacuna-like structures in the peripheral areas. GAG contents in the 2 experimental groups were 5.98 mg/g and 5.62 mg/g respectively, both significantly higher than that in the control group (4.73 mg/g) without a difference between the 2 experimental groups. CONCLUSION: Mechanical stress promotes chondrogenesis and cartilage maturation of BMSC in vitro.

Animals↗

PubMed2004

Fibroblast growth factor receptors as molecular targets in thyroid carcinoma.

Several molecular abnormalities of potential therapeutic target value have been described in thyroid neoplastic transition. We report the expression of the fibroblast growth factor receptor family (FGFR-1-4) in normal thyroid tissues, human thyroid cancers of various types and behaviors, and cell lines representative of the spectrum of differentiation of tumors derived from follicular epithelial cells. FGFR-2 was the only receptor consistently detected in normal human thyroid tissue, and its expression diminished in all thyroid cancers and carcinoma cell lines, suggesting that it may have a protective role. FGFR-1 and FGFR-3 were expressed in most well-differentiated tumor types. FGFR-4, however, was expressed predominantly in aggressive tumor types and the most rapidly proliferative cell lines, indicating that it may promote the progression of these tumors. To specifically determine the function of FGFR-4 in thyroid carcinoma, gain- or loss-of-function studies were performed in cell lines representative of the spectrum of thyroid cancer behavior. Introduction of FGFR-4 resulted in enhanced cell proliferation, an effect that was more pronounced in cell lines derived from aggressive tumors than in those derived from more indolent neoplasms. Moreover, transduction of a dominant-negative FGFR attenuated cell proliferation in the aggressive poorly differentiated cell lines with no appreciable effect in well-differentiated cells. Pharmacologic FGFR-4 tyrosine kinase inhibition resulted in significant proliferation arrest in an aggressive cell line endogenously expressing the receptor. Furthermore, systemic administration of the FGFR tyrosine kinase inhibitor PD173074 resulted in significant inhibition of follicular thyroid carcinoma-derived cell growth in xenografted severe combined immunodeficient mice. These data indicate a role for FGFR-4 in human thyroid cancer cell progression and provide a rationale for FGFR manipulation as a potentially novel therapeutic approach.

Adenoviridae↗

PubMed2004

[Microsurgical treatment of proximal anterior cerebral artery aneurysms].

OBJECTIVE: To explore clinic characteristics of proximal anterior cerebral artery aneurysms and analyzed operative techniques. METHODS: A review was performed of a total of 362 patients whose aneurysms were surgically treated from June 1995 to December 2003, the morbidity of A(1) aneurysms was 2.2%. To reviewed clinical data of 8 proximal anterior cerebral artery aneurysms patients. RESULTS: All of the aneurysms developed at the takeoff point of perforating arteries, the recurrent artery of Heubner in three cases, the medial proximal lenticulostriate artery in five cases. Six cases aneurysms projected posteriorly, two cases projected inferiorly in the surgical field. The shape of the aneurysms was saccular in all cases and diameter no larger than 5 mm in six cases. Patients were clipped satisfactorily, excellent condition in 7 patient, good condition in one. CONCLUSION: It is important to preserve the perforating arteries and use suitable clip by avoiding cerebral ischemia.

Adult↗