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Lei Yang

Publications and source records attributed to Lei Yang.

At least 91 records · Page 5Linked to original sources
PubMed2004

[Study of osteoblasts transfected with gfp in vitro and traced in vivo].

OBJECTIVE: To observe the osteoblasts transfected with green fluorescent protein (GFP)by adenovirus vector expressed in vitro and traced it in vivo in order to research the feasibility of GFP as a tracer of seeding cells for tissue engineering. METHODS: CFP were transfected into the osteoblasts which derived from adult human bone marrow stromal cell (hBMSc) by adenovirus vector after being packed in 293A cells. The nontransfected hBMSc was used as the control group. The osteoblasts in each group were observed under an inverted phase contrast microscope and fluorescence microscope. The expressive efficiency of GFP was examined by flow cytometry,and alkaline phosphatase (ALP) activities and osteocalcin (OCN) synthesis. After eight days of the transfection,the osteoblasts were implanted into the muscle of nude mouse thigh while the non-transfected osteoblasts were also implanted as a control. Four and eight weeks after the operation, the nude rats were killed and the continuous tissue sections were examined using fluorescence microscopy after adjacent sections were performed by immunohistochemistry or routine HE staining. RESULTS: The green fluorescence was shown the transfected osteoblasts which derived from bone marrow. The rate of positive expression was over 75%. After eight days of the transfection, the marker proteins of the surface of the osteoblasts showed extremely efficient expression of CD29 and CD44, but the CD34 expressed negative. Either ALP or OCN of the osteoblasts was no significant difference between the two groups (P > 0.05) four and eight days after the transfection. The GFP were obviously expressed in nude mouse both at four and eight weeks, meanwhile it did not harm on the morphology and function of the transfected osteoblasts whose immunohistochemistry examination showed positive reaction. CONCLUSIONS: GFP could be transfected osteoblasts effectively in vitro and traced in vivo in nude mouse. It may be an optimal tracer for living cells on tissue engineering research.

Adult↗
PubMed2003

New trends in the development of occupational exposure limits for airborne chemicals in China.

Occupational exposure limits (OELs) are well established in many countries, which serve occupational professionals as benchmarks of industrial hygiene practice at workplaces worldwide. Starting in the mid-1950s, the central government of China began promulgating OELs for hazardous substances at workplaces. This paper discusses the historical basis, philosophical principles and schematic protocols of developing and setting OELs in China. The underlying principles include: (1) protection of human health being the first and the most important criterion; (2) the use of quantitative epidemiological studies in humans being given top priority; (3) integration and full use of all information sources, including animal experimental data for new chemicals or chemicals with new toxicity concerns; (4) considerations of socioeconomic and technological feasibilities in the country; and (5) amending existing standards based on new evidence. The strategy of the World Health Organization's "Two-step Procedure" is applied to convert health-based recommendations to law-based operational OELs, with considerations for national technological and socioeconomic conditions and priorities. As a result of the recent passage of the new law Occupational Diseases Prevention and Control Act of the People's Republic of China (ODPCAct), an official document Occupational Exposure Limits for Hazardous Agents in the Workplace containing a comprehensive list of new and amended OELs has been issued, which has now become one of the most essential regulations affiliated with the ODPCAct. This paper provides a brief summary of the salient features of the new law ODPCAct and the principles and processes of developing or amending OELs. This paper also discusses the challenges that lie ahead in enforcing the new regulations in China.

Air Pollutants, Occupational↗
PubMed2003

[Detection of severe acute respiratory syndrome (SARS)-associated coronavirus RNA in autopsy tissues with in situ hybridization].

OBJECTIVE: To explore the distribution of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) in SARS autopsy tissues at the molecular level. METHODS: In situ hybridization was used to detect the expression and location of SARS-CoV RNA polymerase gene in autopsy tissues from SARS-Cov-infected subjects, including the lung, spleen, lymph nodes, pituitary, pancreas, parathyroid, adrenal glands, gastrointestinal tract, skin, brain, liver, kidney, blood vessels, striated muscles of the limbs, bone marrow, heart, ovary, uterus and testicles. RESULT: SARS-CoV RNA was detected in the cytoplasm of the alveolar epithelia, infiltrating mononuclear phagocytes in the lungs, serous gland epithelium of the trachea/bronchus, monocytes in the spleen and lymph nodes, acinar cells in the pancreas, acidophilic cells in the parathyroid and pituitary, adrenal cortical cells, epithelia of the alimentary tracts, gastric parietal cells, sweat gland cells, brain neurons, hepatocytes near the central vein, epithelia of the distal renal tubules, bone marrow promyelocytes, and endothelia of the small veins. CONCLUSIONS: SARS-CoV invades various organs of the body and distributes in a similar fashion to CD13, the receptor of human coronavirus 229E. The detection of SARS-CoV in the sweat glands, alimentary tracts and epithelia of the distal convoluted tubules of the kidney may help identify the transmission routes of SARS-CoV.

Autopsy↗
PubMed2003

[Expression of the monoclonal antibody against nucleocapsid antigen of SARS-associated coronavirus in autopsy tissues from SARS patients].

OBJECTIVE: To investigate the presence and distribution of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) in autopsy tissues obtained from patients died of SARS. METHODS: Immunohistochemical technique was applied in 4 fatal SARS cases to examine the autopsy tissues including the lungs, spleen, lymph nodes, brain, pituitary, heart, liver, kidney, pancreas, trachea, esophagus, gastrointestinal tract, adrenal glands, parathyroids, skin and bone marrow. RESULTS: Immunohistochemistry identified positive monoclonal antibody against SARS-CoV nuceeocapsid (N) protein in the alveolar epithelium and the infiltrating monocytes or macrophages in the lung, spleen and lymph nodes; the presence of the antibody was also detected in the serous gland epithelium of the trachea/bronchus, squamous epithelium of the esophagus, the gastric parietal cells, the epithelium of the intestinal tract, acidophilic cells in the parathyroids and pituitary, acinus cells in the pancreas, adrenal cortical cells, sweat gland cells, small vessel endothelium, bone marrow promyelocytes, epithelial cells of the distal convoluted tubule of the kidney, brain neurons, and the hepatocytes near the central vein. CONCLUSIONS: A variety of organs and tissues can be infected by SARS-CoV, and the positive expression of SARS-CoV N protein in the epithelial cells of the gastrointestinal tract, the distal convoluted tubule of the kidney and the sweat gland cells is significant for studying the transmission routes of SARS.

Antibodies, Monoclonal↗
PubMed2003

[Clinicopathological analysis of 2,037 patients with colorectal cancer in Guangdong Province].

OBJECTIVE: To study the clinicopathological characteristics of colorectal cancer in Guangdong Province. METHODS: Statistical analysis was conducted in the 2 037 cases of colorectal cancer treated in Nanfang Hospital of First Military Medical University from 1986 to 2002. RESULTS: The patient cohort consisted of 1 165 males (57.19%) and 872 females (42.81%), with a male to female ratio of 1.34 1. The high-risk age range for colorectal cancer was 41-70 years (making up 70.74% of the total patients). The annual number of newly identified patients began to rise in 1994, and the rectum still remained the most frequently involved site (55.87%), but colonic cancer tended to increase (44.13%). Compared with their seniors, young patients (age 40) were prone to be affected by right colonic cancer. Dukes staging showed that most of the patients were in middle or advanced stages (96.17%), and most cases were histologically identified as adenocarcinoma (71.18%), but a poorly differentiated carcinoma was more likely to be found in young patients (35.96%) than in their elders (12.74%). CONCLUSION: The incidence of colorectal cancer increases annually and most of the identified cases are in middle or advanced stages. Many young patients have a hereditary predisposition and the knowledge of prevention and self-protection of colorectal cancer is of significant value. Screening and early diagnosis and early treatment may help improve the survival rate among the high risk population.

Adolescent↗
PubMed2003

[Study on the disabilities in aged 0-7 years children in Shenzhen, China].

OBJECTIVE: To explore the prevalence of vision, mental, audibility, language, psychiatry, extremity, and influence factors in the 0 - 7 year olds. METHODS: A total number of 77,727 0 - 7 year old children living in Shenzhen city were tested with tree phase screening under the Chinese standard of evaluation in disabilities. RESULTS: The prevalence of all disabilities was 5.59 per thousand (adjusted rate was 8.49 per thousand with a false negative of 3.1 per thousand ). The prevalence of mental disease was the highest (1.88 per thousand, with adjusted rate 3.43 per thousand ), the prevalence of language disability was 1.88 per thousand (including retarded language development, with adjusted rate 3.43 per thousand ). The prevalence rates of psychiatry, extremity and audibility disability were 1.59 per thousand, 1.56 per thousand, 1.11 per thousand respectively with of vision the lowest (0.37 per thousand ). The prevalence of all disabilities, audibility, language and mental was on the increase with age. The difference was statistically significant. Among all different age groups regarding psychiatric disease, the highest fell in the 2 - 4 year olds. The prevalence of extremity was not statistically different among age groups. The suspected agents of disease which occurred before or during pregnancy took up 45.7%. CONCLUSION: The prevalence of six kinds disabilities in Shenzhen was about 10 per thousand lower than that of the samples of the nation in 1989, but two times higher than that of similar studies in Japan. The prevalence rates of language and psychiatric disease were higher than that of the nation in 1989. The causation should be further studied.

Age Factors↗
PubMed2003

[Immunohistochemical method for the detecting expression of transforming growth factor-beta1 in lung tissues of silica-treated mice].

OBJECTIVE: To investigate the protein expression of transforming growth factor-beta(1) (TGF-beta(1)) in lung tissues of silica-treated mice. METHODS: The experimental mice were divided into control and silica groups. 0.2 g/kg body weight of silica was injected intratracheally in mice of silica group. Samples of lung tissue were collected 1, 3, 5, 7, 14 and 28 d after injection. The immunohistochemical method was used to analyze the protein expression of TGF-beta(1). RESULTS: In control mice, the expression of TGF-beta(1) in lung tissue was slightly positive while it was markedly increased in silica-treated mice. The expression was significantly elevated from the 7th day to 14th day. The expression in alveolar macrophages reached the peak on the 5th day [(93.4% +/- 2.8%) vs (42.2% +/- 12.0%), P < 0.01]. CONCLUSION: TGF-beta(1) may play an important role in early development of silicosis.

Animals↗
PubMed2003

[RT-PCR method for detecting the expression of transforming growth factor-beta1 gene in lung tissues of silica-treated mice].

OBJECTIVE: To investigate the gene expression of transforming growth factor-beta(1) (TGF-beta(1)) in lung tissues of silica-treated mice. METHODS: The experimental mice were divided into control and silica group. 0.2 g/kg body weight of silica was injected intratracheally in silica group. Samples of lung tissue were collected 1, 3, 5, 7, 14 and 28 d after injection. RT-PCR method was used to analyze the gene expression of TGF-beta(1) in lung tissue of silica-treated mice. RESULTS: The expression of TGF-beta(1) gene in lung tissue elevated from the 3rd day (1.20 +/- 0.15) and the peak value was on the 7th day (1.74 +/- 0.19). Then the expression decreased from the 14th to 28th day. But there was still higher than control until the 28th day. CONCLUSION: TGF-beta(1) may play an important role in silica-induced pulmonary fibrosis.

Animals↗
PubMed2002

Heat conduction and entropy production in a one-dimensional hard-particle gas.

We present large scale simulations for a one-dimensional chain of hard-point particles with alternating masses and correct several claims in recent literature based on much smaller simulations. We find heat conductivities kappa to diverge with the number N of particles. These depended strongly on the mass ratio, and extrapolations to N--> infinity, and t--> infinity, are difficult due to very large finite-size and finite-time corrections. Nevertheless, our data seem compatible with a universal power law kappa approximately N(alpha) with alpha approximately 0.33 suggesting a relation to the Kardar-Parisi-Zhang model. We finally discuss why the system leads nevertheless to energy dissipation and entropy production, in spite of not being chaotic in the usual sense.

Journal Article↗
PubMed2002

Finite heat conduction in a 2D disorder lattice.

Recently, the thermal conductivity in disordered chains has attracted a lot of attention, including the discussion of the disorder anharmonic and harmonic chains. A natural problem concerns the higher-dimensional disordered lattice system. This paper gives a 2D harmonic lattice model with missing bond defects. When the defect density is large enough, a temperature gradient builds up and a finite heat conduction is found in this model.

Journal Article↗
PubMed2002

Response to pain by different gestational age neonates.

One hundred infants were divided into the following 3 gestational age (GA) groups: (I) premature infants (n = 30) with the gestational age between 29 and 32 weeks; (II) premature infants (n = 30) with the gestational age between 33 and 36 weeks; (III) full-term infants (n = 40). The recorded responses of all infants to pain included the behavioral responses to painful stimuli (cry, facial activity and limbs movement) and the variety of heart rate. The results indicated that the infants of 3 groups had different degree response to various painful stimuli. Pain expression in full term infants was more significant than premature infants to same stimuli. 33-weeks GA infants were differential from 29-weeks GA infants. Full term infants showed more vertical mouth stretch and more taut tongue and more hand to mouth than premature infants, but more horizontal mouth stretch in premature infants.

Gestational Age↗
PubMed2002

Increased expression of intranuclear AChE involved in apoptosis of SK-N-SH cells.

Programmed cell death plays an integral role in neurodegenerative diseases such as Alzheimer's disease (AD). Acetylcholinesterase (AChE) was suggested to be neurotoxic in vivo and in vitro and accelerate assembly of amyloid peptide into Alzheimer's fibrils. In our experiments, we found increased AChE expression in apoptotic neuroblastoma SK-N-SH cells after long-term culture. Our results first showed that in apoptotic SK-N-SH cells, AChE aggregated in the nucleus and suppression of AChE expression with antisense oligonucleotide could save the cells from apoptosis. It was also found that caspase-3 activity was parallel with AChE activation in apoptotic SK-N-SH cells. These results suggest that AChE plays an important role in the procession of neuroblastoma cell apoptosis and favor the association between AChE and neuronal apoptosis in AD.

Acetylcholinesterase↗
PubMed2002

Experience in the treatment of patients with burns covering more than 90% TBSA and full-thickness burns exceeding 70% TBSA.

OBJECTIVE: The objective of this study was to explore our experience in the treatment of serious burn patients (total burn surface area [TBSA] > 90% and full thickness burns > 70% TBSA). METHODS: Thirty patients who were admitted to our unit over a period of 12 years were analyzed retrospectively; 23 cases (76.7%) were successfully treated. RESULTS: There were seven out of 12 cases (58.3%) in the first 5 years and 16 out of 18 cases (88.9%) in the latter 7 years of the study period. CONCLUSIONS: It is concluded that: 1) giving electrolyte-free fluids (around 3700 ml) and the maintenance of hourly urine output at 70 ml or more appear to be beneficial in resuscitation therapy; 2) the first operative procedure should be undertaken early, at about the third day after injury; 3) a higher percentage area of eschar to be excised in the first operation is encouraged and eschar excision of up to 40% or more is preferable; 4) controlling the area of exposed wound under 5% in the entire therapeutic course is essential in the prevention of burn infection; 5) emphasis should be placed on the vital role of a dehumidifier in reducing the incidence of fungal infection; and 6) early enteral nutrition with the use of growth hormone in correcting the nutritional state of the patient is also emphasized.

Adolescent↗
PubMed2002

Study on the screening of molecular structure parameter in QSAR model.

Based on the analysis of information flow through the Artificial Neural Network (ANN), a new screening rule of the molecular structure parameter in Quantitative Structure-Activity Relationship (QSAR) was presented by comparing of the values of connection weights and biases of the ANN model. The result showed that model quality and prediction ability of QSAR model, which was constructed by screening structural parameter with ANN, were better than by the method with MLR. The method established the foundation for further study in the mechanism research of the bio-toxicity of organic chemicals.

Animals↗
PubMed2002

Variations of elemental distribution in brain regions of neonatal rats at different iodine intakes.

Iodine deficiency (ID) can result in irreversible damage to the brain during the fetal and neonatal stages. As the active center of many enzymes, trace elements play essential roles in brain function. In this work, the relative contents and distributions of elements (Cl, Br, Fe, Cu, and Zn) in two important brain regions, the cerebral cortex and hippocampus, of the iodine-deficient model rats were determined by the synchrotron radiation X-ray fluorescence (SRXRF) method. Meanwhile, the ID rats were supplemented with adequate and excessive iodine, respectively. The results indicated that the distributions of trace elements could be influenced by the different iodine intakes in the stage of brain development. In contrast to the control group, the contents of Cl, Br, and Zn in two brain regions showed a significant increase in the ID group; however, both Fe and Cu decreased in the cerebral cortex and increased in the hippocampus in the ID group. In addition, only slight changes of elemental contents in brain were found between the adequate and excessive iodine-supplemented rats.

Animals↗