Biomedical subjects

W Yang

Publications and source records attributed to W Yang.

At least 127 records · Page 7Linked to original sources

PubMed2001

[Preparation, characterization and evaluation of cellulose tris (3,5-dimethylphencarbamate) chiral stationary phase].

With the deposition of cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) on aminopropylated silica gel (mean particle size, 5 microns; pore size, 13 nm; surface area, 110 m2/g) by using two different methods (evaporation and precipitation), two chiral stationary phases (CSP1 and CSP2) characterized by elemental analysis and scanning electron micrography were obtained. They were also evaluated by using seven racemic compounds with n-hexane/ethanol(95/5, V/V) and n-hexane/2-propanol (90/10, V/V) as mobile phases. The results showed that the chiral stationary phase CSP1 obtained by the evaporation method had better efficiency and chiral resolution ability than CSP2 by the precipitation method.

Benzoin↗

PubMed2001

[Herpesviridae and laryngeal neoplasia].

OBJECTIVE: To investigate the relationship between herpesviridae and malignant or benign laryngeal diseases. METHOD: 128 paraffin-embedded laryngeal squamous cell carcinoma and laryngeal epithelium hyperplastic lesions were detected by polymerase chain reaction (PCR) and PCR-ISH for herpesviridae. RESULT: HSV-1 was detected in 10 cases by PCR, among them 3 were laryngeal squamous cell carcinoma (LSCC), 1 was carcinoma in situ(CIS), 4 were laryngeal polyps and 2 were laryngeal keratosis. Except 1 LSCC and 1 CIS 8 of 10 cases were positive while detected by PCR-ISH. In benign diseases, signals were shown from basal layer to superficial cell; in malignant lesions, the signals were scattered in the diseases. CONCLUSION: Most of laryngeal diseases were not related to herpesviridae, but HSV-1 may acts as initiator in the development of a few cases.

Carcinoma, Squamous Cell↗

PubMed2001

[Isolation of outer hair cells from varying turns of the guinea-pig cochlea].

OBJECTIVE: To probe the method of isolating outer hair cells (OHC) from each of four turns of the guinea-pig cochlea. METHOD: From eight guinea pigs the organ of Corti from each of four turns of the cochlea were dissected, and then treated using enzyme. RESULT: A fair amount of living OHCs from each of four turns were obtained. The length of OHCs from each of four turns were 23.81, 34.50, 60.48 and 71.37 microns. CONCLUSION: The key to success in isolating OHCs from each of four turns of the cochlea is to know very well the anatomical characteristics of each of four turns of the cochlea and be operated in accordance with normal rules.

Animals↗

PubMed2001

[The mechanism of neuro-2a cell death induced by H2O2].

Reactive oxygen species (ROS), such as H2O2, can be produced by enzymes involved in electron leakage of respiration chain in mitochondria, and by neurochemical enzymes such as monoamine oxidase in neural cells. ROS are toxic to cells, and can result in cell death. ROS also play an important role in some diseases, especially in neurodegenerative diseases by yet unknown mechanisms. In the current research, the N-2a neuroblastoma cell was treated with H2O2, and the morphological changes of cell death were characterized. Our results show that N-2a cell death is different from classical apoptosis, but belongs type II nerve cell programmed death, which shows condensed chromatin within intact nuclear envelope and no apoptotic body. The chromatin DNA of dead cells shows no internucleosomal cleavage, as well as no requirement for caspase-3, 1 activity. However, the H2O2-induced N-2a cell death can be inhibited by Bcl-XL. It can be concluded that type II nerve cell death is the result of cell toxicity mediated by ROS. The results pave the way for further research of type II nerve cell death.

Animals↗

PubMed2001

[Isolation and characterization of a plasmid pTS50, which encodes nisin resistance determinant in Lactococcus lactis TS1640].

Three nisin-resistant Lactococcus lactis strains were screened from 197 samples of fresh milk on a selective medium (M17) supplemented with nisin, lactose and bromocresol purple, and were confirmed to have the nisin resistance determinant (nsr) by PCR amplification. Physiological and biochemical tests as well as Lactococcus lactis specific 16S rDNA sequence analysis revealed that the three strains all belong to Lactococcus lactis subsp. lactis. A large plasmid, pTS50, was identified in L. lactis subsp. lactis TS1640 which encodes resistance to nisin following electroporation of the total plasmids DNA into L. lactis MG1363. The molecular weight of plasmid pTS50 was estimated to be 47 kb by restriction analysis of BamHI, EcoRI, HindIII, NcoI, PstI and nsr was localized on a 1.9 kb EcoRI fragment by Southern hybridization.

Animals↗

PubMed2001

[Effects of microwave radiation on the content of five elements in mice bone tissue].

Mice were radiated with 2450 MHz, 10 mW/cm2 microwave for 12 days, 1.5 h/day. After microwave radiation, compared with the normal control, the content of calcium and zinc in mice bone were significantly decreased (P < 0.05) copper, iron and manganese decreased, appulsively After Libido, a composed traditional herb medicine, and asshide asafetida were supplied seperatively, the content of calcium and trace element zinc in mice bone increased (P < 0.05). It is concluded that Libido was effective on the resistance of mice to microwave radiation. The toxicity of organotin compounds and the current pollution status.

Animals↗

PubMed2001

[Analysis of MRI for tumor of the sellar region].

PURPOSE: To introduce the characteristics of magnetic resonance imaging(MRI) for the tumors of the sellar region. METHODS: A retrospective analysis of 86 cases with the tumors of the sellar region was carried out. RESULTS: The pituitary tumor including the pituitary micro-adenoma and pituitary macro-adenoma was a common tumor of the sellar region. The pituitary micro-adenoma usually does not affect visual function; but the pituitary macro-adenoma often damages the optic pathway and reduces the visual function. The rest of the sellar region appears special feature on MRI. CONCLUSION: MRI is a useful method in diagnosing the tumors of the sellar region.

Adenoma↗

PubMed2001

Foldable lens explantation and exchange: the reason and solution.

OBJECTIVE: To report the explanation and exchange of Hydrophilic Acrylic foldable intraocular lens (IOL) on 14 patients who had visual disturbances caused by the change of transparence on optic. METHODS: Sixteen Hydrophilic Acrylic foldable intraocular lenses from 14 patients who presented with decreased visual acuity from 6 months to 1 year after normal phacoemulsification and IOL implantation associated with extensive transparent change on optic of the lens. The lenses were explanted with the bisection technique. All the eyes were reinserted with Acrysof foldable lenses. RESULTS: Sixteen lenses were removed successfully and exchanged with the new lens in the capsule. The posterior capsular rupture and vitreous loss were found in the first two cases. One of them had the zonulysis due to the radial tear of the anterior capsule during the enlargement of the capsular opening. The anterior vitrectomy was performed with IOL fixed on the ciliary sulcus. The visual acuity of all the patients improved obviously without posterior complication. CONCLUSION: Foldable lens explanation with the bisection technique and exchange had a successful outcome with improvement of ocular condition.

Acrylates↗

PubMed2001

Treatment of neovascular glaucoma using trabeculectomy combined with implantation of silicon rubber slice.

PURPOSE: To observe clinical effect of treatment for neovascular glaucoma using trabeculectomy combined with implantation of silicon rubber slice. METHODS: 28 cases(28 eyes) with neovascular glaucoma were performed trabeculectomy combined with a piece of 3 x 5 mm silicon rubber implantation, and their lowing intraocular pressure effect was observed. RESULTS: All patients were follow-up for 9-24 months (mean: 18.3 months). The average intraocular pressure at last visit was 21.65 mmHg (rang: 17.30-28.97 mmHg, 1 mmHg = 0.133 kPa). The symptom of eye pain was disappeared after surgery. CONCLUSION: Trabeculectomy with a piece of silicon rubber implantation is ideal therapy for neovascular glaucoma.

Adult↗

PubMed2001

[Overexpression of cyclin A leads to S-phase arrested apoptosis].

OBJECTIVE: This study was aimed to gain an insight into the molecular basis of S-phase arrest associated apoptosis. METHODS: The molecular expressions of Rb, cyclin A, cyclin E, CDK2 and CDC2 involved in S-phase progression were investigated by westernblot in L-2 and Br1-3pr-1 cells. Furthermore, their associated kinase activities were assayed by histone, phosphorylation. RESULTS: The results showed that ofter PALA treatment, the expression of cyclin A increased and the expression of Bcl-2 decreased in apoptosising L-2 cell as compared with those in unapoptosising Br1-3pr-1 cell, but there were no significant differences in other molecular expressions and associated kinase activities between the above-mentioned L-2 cell and Br1-3pr-1 cell arrested at S phase after PALA treatment. CONCLUSION: Cyclin A is a most potential candidate for S phase checkpoint element, and it may be able to induce the S phase arrest associated apoptosis through the Bcl-2 pathway.

Apoptosis↗

PubMed2001

[Effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in the guinea pig].

OBJECTIVE: To define the effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in guinea pigs. METHODS: The animals involved in the study were exposed to 8 Hz infrasound at 135dB SPL for 90 minutes in a reverberant chamber. The sinusoidal pendular test (SPT), auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) were respectively detected pre-exposure and at 0(within 2 hrs), 2 and 5 day after exposure. The ultrastructures of the inner ear were observed by scanning electron microscopy. RESULTS: The slow-phase velocity and the frequency of the vestibular nystagmus elicited by sinusoidal pendular test (SPT) declined slightly following infrasound exposure, but the changes were not significant (P > 0.05). No differences in the ABR thresholds, the latencies and the interval peak latencies of I, III, V waves were found between the normal and the experimental groups, and among experimental groups. The amplitudes of DPOAE at any frequency declined remarkably in all experimental groups. The ultrastructures of the inner ear were damaged to different extent. CONCLUSION: Infrasound could transiently depress the excitability of the vestibular end-organs, decrease the function of OHC in the organ of Corti and cause damage to the inner ear of guinea pigs.

Animals↗

PubMed2001

[Multiple factors analysis of intraoperative bleeding and recurrence of juvenile nasopharyngeal angiofibromas].

OBJECTIVE: To study the effect of surgical treatment of juvenile nasopharyngeal angiofibromas and the factors influencing intra-operative bleeding and recurrence. METHODS: Thirty-four patients with juvenile nasopharyngeal angiofibromas treated surgically in Chinese PLA General Hospital between 1986 and 1999 were studied retrospectively. The relationship between surgical treatment, intraoperative bleeding, recurrence and age, duration, staging, preoperative treatment, times of previous operation, operative approaches was statistically analyzed. RESULTS: The tumors were totally resected in 30 patients, and five patients(16.7%) recurred during a mean follow-up of 77 months. The mean recurrence time after operation was 3.2 months (1-6 months). The amount of intraoperative bleeding correlated well with the age, duration, staging, preoperative treatment, and surgical approaches (P < 0.05), but not with times of previous operation (P > 0.05). Recurrence was not correlated with the age, duration, preoperative treatment and surgical approaches (P > 0.05), but correlated with staging (P < 0.05). CONCLUSION: The factors significantly influencing the intraoperative bleeding were the age, duration and staging. Recurrence was correlated with the tumor stages, incomplete resection or the exceedingly malignant activity of the tumor. Radiotherapy, with a dose of 30Gy, is an adjuvant therapy for incompletely resected, or residual tumors.

Adolescent↗

PubMed2001

[Synergetic protective effects of glial cell line-derived neurotrophic factor combined with neurotrophin-3 in F-actin on hair cell after noise trauma].

OBJECTIVE: To investigate if glial cell line-derived neurotrophic factor (GDNF) combined with neurotrophin-3 (NT-3) provides synergetic protection in filamentous actin (F-actin) on hair cell (HC) from acoustic trauma. METHODS: Guinea pigs were exposed to 4 kHz narrow band noise at 115 dB SPL for 4 h. Test group (n = 12) with a mixture of GDNF (100 ng/ml) and NT-3(2.5 micrograms/ml) or control group (n = 9) with artificial perilymph (AP) was delivered to the scala tympani via a mini-osmotic pump (0.5 microliter/h) for a total of 14 days. Auditory function was assessed by measuring thresholds of auditory brainstem responses (ABRs) elicited by clicks prior to surgery, 3 days after surgery (1 day before noise exposure) and 10 days following noise exposure (before animals were sacrificed), respectively. F-actin, labeled by rhodamine-phalloidin, was examined in the guinea pig cochlea using fluorescence microscopy for quantitative assessment of hair cell damage. RESULTS: There was a statistically significant increase the survival of out hair cell(P < 0.001, P < 0.01) and inner hair cell(P < 0.01, P < 0.01) and decrease in ABR threshold (P < 0.05, P < 0.01) in both the GDNF and NT-3 treated and untreated ear of animals. CONCLUSION: Our findings indicate that GDNF combined with NT-3 may effectively protect the inner ear from noise--induced hearing loss.

Actins↗

PubMed2001

[Surgical treatment of craniofacial recurrent carcinoma].

OBJECTIVE: The patients with craniofacial recurrent cancers after the radiation, chemical and operative therapies were often not able to get effective treatment because their lesions involved in the nervous and vascular structure and the re-radiation therapy was not suitable or chemical therapy was not sensitive to the tumor as well. To improve their survival quality, prevent the fatal complication and prolong their life, the surgical treatment for them was advised. METHOD: Six patients were treated surgically. According to the lesion of extension and position, the different incisions were respectively made. The neoplasms of these patients were resected piece by piece because they usually involved in the important structures, such as the internal carotid artery and cavernous sinus. Then, local defect was repaired with different methods on basis of the individual condition. So, this type of operation could be called as non-defined operation. RESULTS: The lesions in all 6 patients invaded the eye, meninges and encephala, skull base, cavernous sinus and other important structures. After surgical intervene, the patients were all more than one year survival except for one of the patients who died of serous bleeding with corrupted rupture of internal carotid artery. Three patients survived for 4, 5 and 12 years, respectively. CONCLUSION: The craniofacial recurrent carcinomas in late stage could be resected by the non-defined operation, which could prolong the patients life and achieve the desired effect.

Adult↗

PubMed2001

[The effects of streptomycin on the calcium influx in SGCs during depolarization].

OBJECTIVE: To examine the effect of streptomycin on the calcium influx in spiral ganglion cells (SGCs) during depolarization and the differences among different concentrations of streptomycin and SGCs sources with the aim of exploring the mechanism of acute streptomycin ototoxicity. METHODS: The SGCs of guinea pig cochlea were isolated using an enzyme-machine method and loaded with 10 mumol/L Fluo-3/AM for 30 min at 37 degrees C. Dissociated SGCs loaded with Fluo-3 were examined with a confocal microscope (ACAS Ultima, USA) using a 20 x objective lens and linear scan mean. The fluorescent images collected every 5-sec for a total of 300 sec were stored in a computer. The fluorescent intensity of the images was analyzed by a software cooperated with the confocal microscope, and a curve of fluorescent intensity changes against time was obtained. RESULTS: The [Ca2+]i of SGCs was steady under the perfusion with standard extracellular solution. The [Ca2+]i of SGCs increased in 12/14 cells under the perfusion with 150 mmol/L high potassium solution, but increased in only 1/10 cells induced by the high potassium calcium free solution. After treating with 1 mmol/L, 0.1 mmol/L, 0.01 mmol/L streptomycin, the [Ca2+]i of the SGCs perfused with the potassium solution was increased in 0/9, 6/14, 7/13 cells, respectively. After the SGCs were treatment with 0.02 mmol/L streptomycin, the [Ca2+]i of the SGCs perfused with the high potassium solution was increased in 5/10 SGCs from the apical turn and in 0/15 SGCs from the basal turn. CONCLUSION: Perfusion with high potassium media can result in obviously increased [Ca2+]i of the SGCs, and the increase of the [Ca2+]i in the SGCs may originate from the extracellular calcium influx. The calcium influx can be blocked by streptomycin and such effects depend on streptomycin concentrations and SGCs sources.

Animals↗

PubMed2001

[Effect of p14ARF gene on cell growth of human laryngeal tumor cells and expression of endogenous p53 protein].

OBJECTIVE: To explore the inhibitory effect of p14ARF on the cell growth of laryngeal carcinoma and the expression on endogenous p53. METHODS: p14ARF cDNA was transferred to the cell line Hep-2 of squamous cell carcinoma of the larynx by gene transfer to study the cell cycles and the expression of endogenous wild type p53 using flow cytometry, polymerase chain reaction(PCR) and Western-Blotting. RESULTS: Expression of p14ARF significantly affected the Hep-2 cell growth. The clone-forming efficiency of the Hep-2 cells transferred with p14ARF was 57%, compared with empty vector pcDNA3. The number of 48 hours after transfer with p14ARF cDNA at both G0/G1 and G2/M was two fold as the control. The expression of endogenous wild type p53 was significantly enhanced. CONCLUSION: Expression of p14ARF can up-regulate the expression of endogenous wild type p53 and inhibit the Hep-2 cell growth of human laryngeal squamous cell carcinoma at both G0/G1 and G2/M.

Carcinoma, Squamous Cell↗

PubMed2001

[Experimental study on polyaspartic acid inhibition of gentamicin-induced generation of reactive oxygen species in guinea pig cochlea].

OBJECTIVE: To observe the polyaspartic acid(PAA) inhibition of gentamicin-induced reactive oxygen species generation in cochlea of guinea pig and to investigate the protective mechanism of polyaspartic acid on gentamicin ototoxicity. METHODS: Eighty-eight guinea pigs were divided randomly into four groups (GM, PAA + GM, PAA, and Saline). Gentamicin-induced reactive oxygen species (ROS) formation in cochlear tissue was detected directly with electron paramagnetic resonance (EPR) spectrometry at 1st, 5th and 10th day after administration of the drugs. At the same time, ABRs of guinea pigs were recorded and ultrastructural changes of lysosomes in the cochlear hair cells were observed with transmission electron microscopy. RESULTS: 1. At 1st day after administration of PAA and GM, there was some increase in EPR spectrometry in group GM and PAA + GM, There was no significant difference of ABR thresholds and ultrastructural changes of lysosomes in the cochlear hair cells among four groups(P > 0.05). 2. At 5th day, there was significant increase in of EPR spectrometry in group I (37.74 +/- 4.10, P < 0.01). At 10th day after administration of PAA and GM, there was no significant difference in EPR spectrometry among four groups (P > 0.05). In GM group, ultrastructural changes of lysosomes beneath cuticular plate of cochlear hair cells were more significant at 10th day than those at 5th day, including the increased number and volume of lysosome. In group GM, the longer the gentamicin administrated, the more significant increase in ABR thresholds had been noted. CONCLUSION: PAA significantly inhibits gentamicin-induced reactive oxygen species generation in cochlea of guinea pig, which showed that PAA has protective effect on gentamicin-ototoxicity and -phospholipidosis in guinea pigs.

Animals↗

PubMed2001

[Fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid].

A fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid with trytophan in the medium pH 11.01 NH3-NH4Cl is studied. The calibration curve is linear for p-hydroxyphenylpyruvic acid from 0 to 15 micrograms.mL-1 with lambda ex/lambda em = 285/356 nm. The detection limit is 0.37 microgram.mL-1. Twenty replicate determinations of solutions containing 10 micrograms.mL-1 p-hydroxyphenylpyruvic acid show a relative standard deviation of 1.2%. This method can be applied to the determination of p-hydroxyphenylpyruvic acid in serum with satisfactory results.

Calibration↗