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Biomedical subjects

Jun Yang

Publications and source records attributed to Jun Yang.

At least 271 records · Page 15Linked to original sources
PubMed2004

[Enlarged translabyrinthine resection of recurrent acoustic neuroma after suboccipital resection].

OBJECTIVE: To evaluate the technique and the outcome of enlarged translabyrinthine removal of recurrent acoustic neuromas after a suboccipital resection. METHOD: Five patients were proved to have recurrent acoustic neuromas after previous suboccipital removal procedures. Revision surgery was accomplished in these patients using the enlarged translabyrinthine approach by sufficiently removing petrous temporal bone to enlarge exposed sight during the operation. RESULT: The sizes of the recurrent tumors ranged from 2.5 to 4.0 cm. Total removal was achieved in all patients, with no death and other major complications such as intracranial infection and cerebrospinal fluid leakage. The facial nerve function was the same as pre-operative condition. There was no residual tumor showed in CT scans and MRI examinations after operation. The cerebel and brainstem resumed to normal position in each patient. No second recurrences had occurred to date at follow-up of 6 months to 2 years and 7 months. All patients recuperated and came back to work. CONCLUSION: Acoustic neuroma recurs frequently after the suboccipital surgery because there is a residual tumor inside the internal acoustic canal (IAC). The enlarged translabyrinthine approach is the most direct access to acoustic neuroma and the brainstem by which recurrent tumor can be removed is avoided during the second operation. Moreover, it is praisable that there are several advantages such as slight invasion and convenience of facial nerve orientation so as to excellent outcome of facial nerve preservation in the enlarged translabyrinthine surgery.

Aged↗
PubMed2004

[Clinical study on respiratory mechanics of synchronized intermittent mandatory ventilation in premature infants with respiratory failure].

OBJECTIVE: To evaluate the clinical significance of synchronized intermittent mandatory ventilation (SIMV) in prematures infants necessitating assistant ventilation. METHODS: Forty-two premature infants were studied in whom SIMV was used in 24 and intermittent mandatory ventilation (IMV) was used in 18. The parameters of fractional concentration of inspired oxygen (FiO(2)), peak inspiratory pressure (PIP), expiratory tidal volume (V(Texp)), oxygen index (OI), compliance of the respiratory system (Crs) and airway resistance (Raw) were compared. The frequency of administration of sedatives and incidence rate of complications were also compared between two groups. RESULTS: In SIMV group, PIP, V(Texp), Raw and Crs were significant better after 2 hours ventilation (all P<0.05). There were significant difference in FiO(2) after 12 hours and OI at 24 hours in two groups. They were better in SIMV group. Sedatives were less used in SIMV group than IMV group (P<0.05). CONCLUSION: In premature infants, SIMV could reduce FiO(2), PIP, OI, Raw and improve V(Texp), Crs more rapidly when assistant ventilation is necessary. The sedatives are used less in patients on SIMV.

Female↗
PubMed2004

[A study on the association between tea consumption and stroke].

OBJECTIVE: The aim of the study was to investigate the association between tea consumption and stroke. METHODS: A cross sectional study was conducted in autumn, 1998. The subjects were from 12 provinces in China. 15 groups of populations were selected by cluster randomized sampling and each group had about 1000 persons, aged from 35 to 60 years old. 14 212 subjects had complete data for analysis. Data regarding tea drinking would include drinking status, dose and type of teas. Logistic regression was used to analyze the association between tea consumption and stroke. RESULTS: There was a strong inverse correlation between tea drinking and stroke after adjusting other risk factors of stroke (P < 0.05). The odds ratio (OR) of stroke was 0.60 [95% confidence interval (CI): 0.42 - 0.85] for subjects who drank tea compared to those who did not. Increased amount of tea consumption per month was associated with decreased stroke prevalence. The association for tea consumption over 150 gram per month and stroke was statistically significant (P < 0.05) with an OR value of 0.56 (95% CI: 0.36 - 0.89). Analytical results indicated that the OR value was 0.24 (95% CI: 0.06 - 1.01) for black tea and other tea (P = 0.05). The OR value was 0.35 (95% CI: 0.18 - 0.72) for green tea (P < 0.01), and 0.75 (95% CI: 0.51 - 1.11) for jasmine tea (P > 0.05). CONCLUSION: Tea drinking was independently associated with prevalence of stroke which might play a role in the prevention of the disease.

Adult↗
PubMed2004

[Screening, cloning, and analyzing for hSNF5 binding proteins in human fetal brain].

OBJECTIVE: To identify novel binding proteins of hSNF5, a subunit of chromatin remodeling complex in human fetal brain. METHODS: The yeast two-hybrid system was used for this study. Positive cDNA clones were sequenced. Sequence homology and putative functional domains were analyzed and compared with databank. RESULTS: Nine positive clones obtained were analyzed, among which the sequence of one clone was 97% homologous to the 3' mRNA of a hypothetical protein FLJ20643, while other four clones were related to protein coding sequences existed in the GenBank. The rest four clones were not in frame with any known protein coding sequence. CONCLUSIONS: Clones encoding for hSNF5 binding protein exists in cDNA library of human brain. These proteins may recruit chromatin remodeling complex via hSNF5 to modulate the transcription of their target gene and the related cell functions.

Brain↗
PubMed2004

[Heat shock induced transcription of hsp90alpha gene on chromatin template].

OBJECTIVE: A CAT reporter plasmid (pBLCAT3alpha1) driven by the promoter of hsp90alpha was in vitro assembled into chromatin to investigate the transcription activity of the reporter gene upon heat shock. METHODS: A competitive RT-PCR-based technique was used to quantify the promoter activity of hsp90alpha gene on chromatin or naked DNA templates in vitro. RESULTS: The in vitro transcription efficiency was first optimized by using different amounts of whole cell extracts from heat shock-treated HeLa cells. In vitro chromatin assembly was carried out with purified components of chromatin assembly associated factors, core histones and CAT reporter gene driven by the promoter of hsp90alpha gene. Results showed that chromatin formation repressed the in vitro transcription of the gene. CONCLUSION: The heat shock induced transcription of hsp90alpha gene on chromatin template is more efficient than that on naked DNA in vitro.

Chromatin Assembly and Disassembly↗
PubMed2004

[Application and review of the reversed posterior interosseous artery flap in 78 clinical cases].

OBJECTIVE: To assess and review the indications and methods of the reversed posterior interosseous artery flap for repairing soft tissue defects of the hand. METHODS: In the series, three types of flaps were utilized including the reversed posterior interosseous artery flap, the expanded reversed posterior interosseous artery flap and the reversed posterior interosseous artery conjoint flap. 78 clinical cases were treated with this method, in which 12 cases used the expanded reversed posterior interosseous artery flap and 10 cases used the reversed posterior interosseous artery conjoint flap. The flap,ranged from 8 approximately 6 cm to 14 approximately 8 cm, was used to repair the defects of the dorsal hand as far as to the fingerweb. The anatomy of the posterior interosseous artery was observed in the surgical dissection. RESULTS: The posterior interosseous artery was consistently identified in all the 78 cases. In 4 cases, the artery terminated in the middle third of the dorsal forearm, therefore an alternative method of reconstruction was used. In the 53 cases of reversed posterior interosseous flaps, 49 cases healed uneventfully and 4 cases suffered necrosis in the distal border of the flap, but subsequently healed spontaneously. 12 cases of expanded flaps survived well and the donor sites were directly approximated. In the 9 cases of conjoint flaps based on the posterior interosseous artery, 7 cases healed uneventfully and 2 cases suffered delayed healing because of flap necrosis of the distal part. The satisfactory appearance and hand function were achieved postoperatively in all cases. CONCLUSIONS: The flap is a better choice for repairing the soft tissue defects of the hand. The different type of flaps can be selected to meet the clinical requirements of reconstruction. It is suggested that the artery variation should be assessed preoperatively.

Adult↗
PubMed2004

Study of a novel antiosteoporosis screening model targeted on cathepsin K.

OBJECTIVE: To establish an effective assay to access the effects of natural products on cathepsin K for screening antiosteoporosis drugs. METHODS: To obtain the purified cathepsin K, we cloned the target fragment from the mRNA of human osteosacoma cell line MG63 and demonstrated its correctness through DNA sequencing. Cathepsin K was expressed in a high amount in E. coli after IPTG induction, and was purified to near homogenetity through resolution and column purification. The specificity of the protein was shown by Western blotting experiment. The biological activity of the components in the fermentation broth was assayed by their inhibitory effects on cathepsin K and its analog papain. RESULTS: With the inhibition of papain activity as a screen index, the fermentation samples of one thousand strains of fungi were tested and 9 strains among them showed strong inhibitory effects. The crude products of the fermentation broth were tested for their specific inhibitory effects on the purified human cathepsin K, the product of fungi 2358 shows the highest specificity against cathepsin K. CONCLUSIONS: The compounds isolated from fungi 2358 show the highest biological activity and are worth further structure elucidation and function characterization.

Biological Assay↗
PubMed2004

Blood pressure change with age in salt-sensitive teenagers.

OBJECTIVE: To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing. METHODS: Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years. RESULTS: After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7 +/- 12.1 mmHg vs. 2.8 +/- 5.2 mmHg, P < 0.01; 12.2% +/- 12.0% vs. 2.5% +/- 4.4%, P < 0.001, respectively). There was a similar trend for diastolic blood pressure (8.4 +/- 6.4 mmHg vs. 3.7 +/- 6.4 mmHg, P = 0.052; 13.2% +/- 10.6% vs. 6.8% +/- 10.1%, P = 0.053, respectively). CONCLUSIONS: Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.

Adolescent↗
PubMed2004

[Saltation behavior in excitation spectra of fluorescent molecules].

Excitation spectra are commonly used to study relationship between molecular structure of fluorescent substances and energy transfer during the fluorescence process. It is generally taken for granted that the excitation spectrum of the sample is equivalent to its absorption spectrum, even a copy of the latter. However, exceptions have been found in many cases. Considering various factors that affect the excitation spectra of solution comprehensively, a model has been established to study the behavior of the excitation spectra. After analyzing the model mathematically, including introducing catastrophe theory, we came into the following conclusions: As far as the topological properties are concerned, the excitation spectra are the same as its absorption spectra, provided the concentration of the substance is below a threshold. However, when the concentration is beyond the threshold, the excitation spectra undergo a series of topological saltation, leading to significant a deviation from the absorption spectra. Comparative studies of both excitation and absorption spectra of naphthalene dissolved in n-hexane confirmed the above hypothesis.

Absorption↗
PubMed2004

[Alcohol consumption and incidence of ischemic stroke in male Chinese].

OBJECTIVE: To assess the relationship between incidence of ischemic stroke and alcohol consumption. METHODS: The information on alcohol consumption and other cardiovascular risk factors such as SBP, DBP, TC was collected among 10 populations in northern and southern parts of China according to the international standardized methods. A total number of 30 560 men and women aged 35 - 59 were enrolled and followed up for an average of 15.2 years. Complete data on 12,352 men was analyzed. RESULTS: The risk on ischemic stroke incidence showed a graded association. Compared with nondrinkers, the relative risks of incidence of ischemic stroke for those who drank alcohol less then 15 gram per day, 15-30 gram per day, 30-60 gram per day, above 60 gram per day were 0.86 (95% confidence interval 0.57-1.27), 1.20 (0.87-1.65), 1.26 (0.86-1.84) and 1.96 (1.30-2.93), respectively. CONCLUSION: Our study revealed that in male Chinese, heavy alcohol intake significantly increased the risk while mild alcohol drinking did not increase the risk of ischemic stroke.

Adult↗
PubMed2004

[Determination of curcumin in urine by capillary electrophoresis].

The major component of the plant curcuma longa (a widely cultivated tropical plant in Asia and Central America) is curcumin. Curcumin has been reported to have very strong anti-inflammatory, anti-carcinogenic, anti-oxidant, antiallergic, anti-bacterial, and anti-tumor activities. Little is known about the absorption, distribution, and metabolism of curcumin in human beings. The first step in in vivo physiological and pharmacokinetic studies is to develop a method to measure curcumin in body fluid. A rapid capillary electrophoretic (CE) method with diode array detection was established for the determination of curcumin in human urine. It could be rapidly determined within 2.5 min. The optimized experimental conditions were as follows: 15 mmol/L Na2B4O7 as buffer, applied voltage 20 kV, temperature 25 degrees C and detection wavelength 262 nm. The method has been validated and shows good performance with respect to selectivity, reproducibility and limit of detection. Curcumin had good linearity in the range of 10 - 300 mg/L, and the recoveries of curcumin added in urine were more than 96.3% with relative standard deviations (RSDs) less than 2.3%. The method is sensitive, fast and accurate and can be used to determine curcumin in urine.

Curcuma↗
PubMed2004

[Experimental study on biological character changes of human epidermal cells during proliferation culture in vitro].

UNLABELLED: [Abstract] OBJECTIVE: The study was (1) to investigate the biological character changes of human epidermal cells during proliferation culture in vitro and (2) to provide data for construction of engineered skin. METHODS: The foreskin was collected from 20 healthy children. The epidermal cells were isolated with digestion of the foreskin and cultured in vitro. Growth curve was obtained from the data of cell counting. Cell growth kinetics was observed. Meanwhile, clonal analysis and cell size measurement was performed. The rate of keratin 19 (K19) and involucrin expression-positive cells was counted by flow cytometer. Expression of K19 and involucrin mRNA was detected by RT-PCR. RESULTS: When passaged to P6, the keratinocytes from child foreskin could be expanded by (700 +/- 37) times. Flow cytometer results showed that the percentage of K19 expression-positive cells decreased from (66.97 +/- 3.14)% to (4.65 +/- 1.38)% while the percentage of involucrin expression-positive cells increased from (11.65 +/- 1.62)% to (97.03 +/- 2.66)% at P0 and P6 respectively. RT-PCR results showed that expression of K19 mRNA decreased from P0 to P6 while involucrin mRNA kept stable with passage in vitro. CONCLUSIONS: Human epidermal cells of passage 5 maintain proliferation phenotype, which are suitable for skin tissue engineering. Decrease of proliferation phenotype content is partially responsible for the proliferation capacity loss of in vitro cultured epidermal cells.

Cell Proliferation↗
PubMed2004

[Carboxyl terminus truncated HPV58 virus L1 protein expressed with baculovirus system and its bioactivity].

To prepare carboxyl terminus truncated human papillomavirus type 58L1 protein, and study on its in vitro bioactivity. PCR was used to amplify carboxyl terminus truncated HPV 58L1 gene, the product was inserted into the PUCMT cloning vector, preparing recombinant PFastBacHTb containing carboxyl terminus truncated HPV58L1 gene. Further more, the recombinant plasmid PfastbacHTb was used to transform DH10Bac cells, constructing recombinant Baculovirus, then the recombinant virus was successfully used to infect Sf-9 insect cells. After incubating at 27 degrees C for 72 hours, the infected cells were collected and total cellular proteins were extracted. The target protein with MW 58KD was revealed by SDS-PAGE and confirmed by Western blot. The interested protein was purified by ProBond purification system. The purified interested protein was identified to self-assemble into VLPs by Transmission electron microscope, and induce murine erythrocyte hemagglutination, indicating that the given proteins had the conformation of VLPs, collecting, HPV58L1 proteins with carboxyl terminus truncation could be efficiently expressed in baculovirus Sf-9 cells expression system, it has identical in vitro bioactivity to the wild type HPV58L1, The present study is fundmental for preparing HPV58L1 prophylactic vaccine.

Animals↗
PubMed2004

[Roles of endothelin and nitrogen monoxide in the adenine-induced acute renal failure models].

OBJECTIVE: To determine the roles of endothelin (ET) and nitrogen monoxide (NO) in the adenine-induced acute renal failure (ARF) models. METHODS: ARF models were established by feeding adenine in rats. The activity of NO synthase (NOS) in kidneys of rats was tested by NADPH-diaphorase. Expression of endothelin-1 (ET-1) in kidneys of rats was studied by immunoreactivity method. The area densities for ET-1 and NOS expressions in kidneys were determined by CMM3 pathology image analysis system to calculate the mean light density. RESULTS: Expressions of ET-1 in normal rat kidneys were wide and weak, but they were greatly enhanced in medulla renis of the ARF models while remained unchanged in the cortex. The activities of NOS were stronger in the cortex and the inner medulla than in the outer medulla. The renal functions of the ARF models were improved after they were treated with L-argine, but the expressions of ET-1 and NOS were not improved. After the withdrawal of adenine, the ARF model rats recovered gradually in their renal functions, and the same was true for the expressions of ET-1 and NOS. CONCLUSION: ET-1 and NO both play important roles in the occurrence, development and recovery of ARF. It is supposed that L-Arg can partly protect the renal functions of ARF rats.

Acute Kidney Injury↗
PubMed2003

A novel synthesis route for ethylenediamine-protected ruthenium nanoparticles.

A novel method has been developed to prepare water-dispersible ethylenediamine (en)-stabilized ruthenium nanoparticles. The procedure involves the reduction of an en-RuCl(3) complex by sodium borohydride. The Ru nanoparticles so prepared are fairly stable in water. TEM imaging shows a mean diameter of about 2.1 nm for the particles and a narrow particle size distribution.

Journal Article↗
PubMed2003

Synthesis of linked carbohydrates and evaluation of their binding for 16S RNA by mass spectrometry.

A library of linked molecules were synthesized from the common sugar moieties existing in the natural amino glycosides. These linked molecules were screened against bacterial 16S RNA for their binding affinity using a mass spectrometry-based technology. Some of these compounds exhibited low micromolar affinity and could serve as leads for further development as antibacterial agents.

Base Sequence↗
PubMed2003

Hydrodynamic simulation of cell docking in microfluidic channels with different dam structures.

The immobilization of biological cells in micro-devices requires high efficiency and easy control while maintaining cell viability. One approach for cell immobilization is to utilize constriction structures such as dams to trap cells in microfluidics. In this paper, we present a comprehensive hydrodynamic analysis of two different types of constriction structures for cell immobilization: dams either in perpendicular or in parallel to the main flow route. Various structural models and experimental conditions were compared for cell docking and alignment, and the pressure and velocity profiles of the flow in the micro-channels and the hydrodynamic force and shear stress on the docked cells were calculated based on fluid dynamic theory and numerical simulation. The effects of the dam structures and cell docking on the flow properties, the transportation efficiency, and the induced stress on the docked cells were analyzed. Improved hydraulic pressure profiles in the auxiliary inlets were discussed for the modulation of the flow characteristics and attenuation of hydrodynamic forces exerted on the cells. Furthermore, a new design combining the advantages of perpendicular and parallel dam structures was proposed for cell-based microfluidics.

Cell Physiological Phenomena↗