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Biomedical subjects

Yun Li

Publications and source records attributed to Yun Li.

At least 127 records · Page 7Linked to original sources
PubMed2003

[Evaluation of physiological index on treadmill exercise testing of 294 healthy children in Shanghai area].

OBJECTIVE: Dynamic exercise is often used to evaluate the backlog function of cardiovascular system, and the treadmill test is a commonly used dynamic exercise protocol. The study aimed to assess the exercise capacity and cardiovascular response to treadmill exercise in healthy children, and create normal reference values of exercise testing in native children. METHODS: Two huadveds and ninety-four healthy children aged 5 to 14 years were tested using the Bruce protocol on treadmill. RESULTS: Mean exercise capacity in boys increased from 12.2 METs at the age of 5 to 6 years, to 15.2 METs at the age of 13 to 14 years. Mean exercise capacity in girls increased from 11.7 METs at the age of 5 to 6 years, to 12.6 METs at the age of 13 to 14 years. Sex difference was obvious in exercise capacity of children except those at the age of 5 to 6 years. There was no obvious correlation between exercise capacity and the ratio of weight to height. Maximal heart rate ranged from 187 to 235 beats/min. Systolic blood pressure increased gradually until peak exercise was achieved. The mean systolic blood pressure of boys at maximal exercise increased by 38.6 percent compared to resting level, and the girls increased by 34.4 percent. After maximal exercise, mean systolic blood pressure reached resting level in 6 minutes but diastolic blood pressure varied. All children had sinus rhythm at rest. No arrhythmia was recorded during treadmill exercise. However, arrhythmia was found in five children in early recovery period. The incidence of exercise-induced arrhythmia was 1.7 percent. CONCLUSION: Sex difference and age difference was obvious in exercise capacity. In the 21st century, the exercise capacity of children in Shanghai area has approached to the developed country. Using MET as the standardized criterion of exercise capacity is advantageous to standardize maximal or submaximal exercise workloads of all kinds of protocols. Exercise-induced arrhythmia in the early recovery period in children without structural heart disease may not be pathological, but it is necessary for those children to be followed-up.

Adolescent↗
PubMed2003

[Effect of autologous dendritic cells on chronic myeloid leukemia cells in vitro].

OBJECTIVE: To observe the effect of autologous dendritic cells (DC) on positive Philadelphia (Ph+) chromosome cells of Chronic Myeloid Leukemia (CML) in vitro. METHODS: DCs and T cells extracted from the peripheral blood mononuclear cell (PBMNC) of 4 CML patients with Ph+ chromosome in chronic phases were amplified in a special liquid culture system. The survival rates of the Ph+ chromosome cells in the bone marrow mononuclear cells (BMMNC) and the K562 cells were determined by the conventional chromosome assays, after About 3 x 10(5)/ml DC incubating with autologous T cells activated by IL-2 or DCs plus IL-2 for 6 hours. RESULTS: About 3 x 10(5)/ml DC per 2 x 10(6)/ml PBMNC were produced. The cytotoxic effect of the T cells activated by DCs plus IL-2 on the autologous Ph+ chromosome cells was significantly greater than those activated by IL-2 (P < 0.001). The clearance activity of the DC activated T cells on the autologous CML Ph+ chromosome cells was stronger than on the K562 cells (P < 0.001). CONCLUSION: The DCs-activated autologous T cells can effectively inhibit the Ph+ chromosome cells. The cytotoxic effect of the autologous T cells activated by the DCs on the Ph+ chromosome cells could be MHC-restricted.

Adult↗
PubMed2002

Effects of inhaled ozone on pulmonary immune cells critical to antibacterial responses in situ.

The goal of this study was to examine effects from repeated exposure to ozone (O3) on immune cells involved in cell-mediated antibacterial responses in the lungs. Rats exposed to 0.1 or 0.3 ppm O3 for 4 h/day, 5 days/wk, for 1 or 3 wk were analyzed for the ability to clear an intrapulmonary challenge with Listeria monocytogenes or had their lungs processed to obtain pulmonary alveolar macrophages (PAM) and lung-associated lymphocytes for analyses of select cell functions and surface marker expression. The results indicate that repeated inhalation exposure to O3 affected local cell-mediated immunity (CMI) responses as evidenced by effects on clearance of Listeria. However, this modulation was not consistently dependent on exposure concentration or duration. Short-term repeat exposures had more effect on host resistance than did the more prolonged regimen, with rats exposed to 0.1 ppm O3 most adversely impacted. Clearance patterns suggest modifications in innate resistance following 1 wk of exposure to 0.1 ppm O3, but no similar effect following a 3-wk regimen. Exposure to 0.3 ppm O3 appeared to affect both innate and acquired resistance after a 1-wk regimen, but mainly the former after an additional 2 wk of exposure. We conclude that these two mechanisms of resistance are differentially affected by O3 and that distinct time- and O3 concentration-dependent adaptation phenomena evolve for each; that is, in situ adaptation to higher levels of O3 may occur more readily with acquired than with innate/PAM-dependent resistance. A similar pattern of inconsistent effect on PAM and lung-associated lymphocytes was also evident. For example, while 3-wk exposures had a greater effect on PAM reactive oxygen intermediate ROI production, evidence for a significant effect on antibacterial activity was only notable among PAM from rats exposed for 1 wk. Among lung lymphocytes, while 3-wk exposure to 0.1 ppm O3 led to a significant increase in CD25 expression, there was no corresponding increase in responsivity to concanavalin A (ConA); only among cells from 1-wk-exposed rats did lymphoproliferative responses increase. Though investigations of altered immune cell cytokine receptor expression/binding activity are ongoing, results herein provide further evidence to support our longstanding hypothesis that some well-documented effects of O3 exposure on human health are quite likely linked to changes in local immune cell (i.e., PAM and lung-associated lymphocytes) functions, with the latter being related to changes in the capacities of these cells to interact with immunoregulatory cytokines.

Administration, Inhalation↗
PubMed2002

Marine oil spill contingency planning.

According to the practice researching and formulating "The Oil Spill Contingency Plan of South Chinese Sea", this paper analyses and discusses the structure, functions and main contents of marine oil spill contingency planning, programs the organizing and commanding system and emergency response system, and advances the planning and researching method to coordinate comprehensively and to design practically the detailed emergency response steps until to formulate the ease operating programs for the plan implementation(PPI) and the PPI to apply high-techniques supporting emergency administrations and response.

Disaster Planning↗
PubMed2002

Effects of zinc on bone development in mouse embryo in vitro.

OBJECTIVE: This study was designed to explore the effects of zinc on bone development. METHODS: Forelimbs of mice with 16 d gestation were cultured by a rotating device. RESULTS: Contents of OC and (45)Ca and activities of AKP in the bone tissues cultured at zinc-deficiency media and at media with 120 micro mol/L of Zn(2+) decreased significantly. Synthesis of OC, absorption of calcium and activities of AKP in the bone tissues cultures at media with 45 and 70 micro mol/L of Zn(2+) increased significantly. Radiograph of bone tissues showed that length of long bone cultured at zinc-deficiency media and at media with 120 micro mol/L of Zn(2+) shortened and their density reduced, and those cultured at media with 45 and 70 micro mol/L of zinc increased, as compared with self-control bone. Histological analysis showed the death of bone cells and loss of stroma in the bone tissues cultured at media with 120 micro mol/L of Zn(2+), and active proliferation and differentiation of bone cells, and secretion and synthesis of osteoid increased in the bone tissues cultured at media with 45 and 70 micro mol/L of zinc. CONCLUSIONS: Adequate supplementation of zinc could promote formation and development of bone tissues and deficiency or excess of zinc could alter their growth and development and normal metabolism.

Animals↗
PubMed2002

[Preliminary experience of video-mediastinoscopy in clinical application].

OBJECTIVE: To determine the value of video-mediastinoscopy in clinical application. METHODS: The clinical data of 54 patients receiving video-mediastinoscopy were reviewed retrospectively. This operation consisted of cervical mediastinoscopy in 44 patients, parasternal mediastinoscopy in 6, and combined procedures in 4. Of these patients, 18 underwent video-mediastinoscopy for the evaluation of undifferentiated mediastinal disease. Thirty-six patients with suspected lung cancer showed enlarged mediastinal lymph nodes radiographically in the chest and underwent video-mediastinoscopy. RESULTS: Seventeen of 18 patients with undetermined mediastinal diseases had a definitive pathologic diagnosis, with an accuracy of 94.4% (17/18). In the 36 patients with suspected lung cancer, 22 were positive, and 14 negative. In the negative patients who underwent thoracotomy with resection, mediastinal lymph nodes revealed no evidence of metastasis. There were no postoperative complication and deaths. CONCLUSION: Video-mediastinoscopy as a highly effective and safe procedure could be used in the diagnosis and staging of thoracic diseases.

Adolescent↗
PubMed2002

[Electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases].

OBJECTIVE: To evaluate the effect of electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases. METHODS: We determined the position of lesion, separated the lesion from the esophageal wall, resected the lesion and protected the esophageal mucosa during the process of video-assisted thoracoscopic surgery for benign esophageal diseases. RESULTS: Thirty-six patients with benign esophageal disease underwent the operation successfully and recovered uneventfully. There was no operative death or severe perioperative complications such as esophago pleural fistula. Two patients were changed to undergo thoracotomy. CONCLUSIONS: Electronic fiberesophagoscopy is an essential equipment in video-assisted thoracoscopic surgery for benign esophageal diseases. It should be adopted as a routine equipment to ensure the accuracy, safety, reliability and convenience of this kind of operations.

Adolescent↗
PubMed2002

[Study of the effects of zinc on bone development applying fetal mouse limbs culture].

The effects of zinc on bone metabolism is explored. A home-made rotating apparatus is used to cultivate fetal mouse front limbs at 16-day gestational age. The activity of alkaline phosphatase(AKP) and histological silce are used to analyze the effects of zinc on bone metabolism. Compared with the control group, the zinc deprived group and Zn2+ 120 mumol/L group have a lower alkaline phosphatase (AKP) activity and the contracted chromatin, membrane rupture and matrix loss are observed in bone cells. The zinc adequate group(Zn2+ concentration are 45 mumol/L and Zn2+ 70 mumol/L respectively) has a higher alkaline phosphatase(AKP) activity, more active bone generation, deeper stain of bone matrix and increased bone trabecula. It is concluded that zinc could affected the bone metabolism and growth; both zinc-deficiency and zinc-excess could alter growth and bone metabolism.

Alkaline Phosphatase↗
PubMed2002

[The effect of interferon alone, cytosine arabinoside alone and their combined effect on hematopoietic progenitors of chronic myeloid leukemia in vitro].

OBJECTIVE: In order to search for more effective treatment regimen of chronic myeloid leukemia (CML). METHODS: Semisolid culture and conventional chromosome assay were used to evaluate the effect of interferon (IFN) and Ara-c on K562 cell line and BMMNCs from CML patients and normal controls. RESULTS: IFN had no obvious inhibitory effect on K562 cell. IFN and Ara-c had preferential inhibitory effect on CFU-GM growth of CML and selective cytotoxic effect on CML Ph+ cell. The combination of IFN with Ara-c enhanced the cytotoxic effect of IFN or Ara-c alone on CML cells. CONCLUSION: IFN and Ara-c can be selected for therapy of CML in chronic phase. The combination of IFN with Ara-c may be more effective than IFN or Ara-c alone for the therapy of CML.

Adult↗
PubMed2002

[Study on the differentiation of K562 cell-line induced by Tanshinone II A].

OBJECTIVE: To investigate the effect of Tanshinone II A on K562 cell-line and its possible mechanism. METHODS: Cell culture, cytomorphology and cytometrics were used. RESULTS: The proliferative inhibition of K562 cells induced by Tanshinone II A was dose-independent, and the degrees of erythroid differentiation induced by 30 nmol/L ACM and 0.5 microgram/ml Tanshinone II A were not statistically different (P > 0.05). CONCLUSION: Tanshinone II A has an inhibitive effect on the proliferation of K562 cells and an inductive effect on the differentiation of erythrocyte series. The mechanisms may be related to the changes of cell cycle and gene expressions.

Abietanes↗
PubMed2002

[Acute aging model induced by gamma-ray irradiation].

In order to develop a quick and convenient model of acute induced-aging, gamma-ray (3.0 Gy/time for 4 min 53 s for 5 days) is used to irradiate a group of rats, and galactose (40 mg.kg-1.d-1 for 40 days) is injected into a group of mice. At the end of the experiment, the activities of superoxide dismutase (SOD) and content of malondiadehycle (MDA) in the serum of experimental animals are assayed, showing that the gamma-ray irradiation leads to the reduction of SOD activity and an increase in MDA content in the serum of the rats, while galactose injection leas to the reduction of SOD activity and an increase in MDA content in the serum of the mice. The results from this investigation indicate that an acute aging model can be induced by gamma-ray irradiating on rats.

Aging↗
PubMed2002

Effect of zinc on bone metabolism in fetal mouse limb culture.

OBJECTIVE: To determine the effects of zinc-deficiency and zinc-excess on bone metabolism. METHODS: We developed the culture model of fetal mouse limbs (16th day) cultivated in self-made rotator with continuing flow of mixed gas for six days in vitro. The cultured limbs were examined by the techniques of 45Ca tracer and X-roentgenography. RESULTS: The right limbs cultivated had longer bone length, higher bone density than the left limbs uncultivated from the same embryo; and histologically, the right limbs had active bone cell differentiation, proliferation, increased bone trabecula, clearly calcified cartilage matrix, and osteogenic tissue. Compared with the control group, the zinc-deficient group and zinc-excess (Zn2+ 120 mumol/L) group contained less osteocalcin (BGP) and 45Ca content, and lower AKP activity; whereas zinc-normal (Zn2+ 45 mumol/L and Zn2+ 70 mumol/L) groups contained more BGP and 45Ca contents, and higher AKP (alkaline phosphatase) activity. CONCLUSION: Both zinc-deficiency and zinc-excess can alter bone growth and normal metabolism. The results indicate that the culture model of fetal mouse limbs (16th day) in vitro can be used as a research model of bone growth and development.

Alkaline Phosphatase↗
PubMed2002

[Non-penetrating trabecular surgery with application of mitomycin C].

OBJECTIVE: To evaluate the clinical effect of non-penetrating trabecular surgery (NPTS) with mitomycin C (MMC) in primary open-angle glaucoma (POAG). METHODS: Twenty-five eyes of 18 patients with POAG underwent NPTS with MMC during the operation. The mean follow-up was 16.6 months (6 - 28 months). RESULTS: The mean preoperative intraocular pressure (IOP) was (27.93 +/- 7.62) mm Hg (1 mm Hg = 0.133 kPa) which decreased to a mean postoperative IOP of (14.62 +/- 3.53) mm Hg (P < 0.001). After operation, there was an obvious diffuse bleb in each eye, in the 3 months after operation, there were functional blebs in 21 eyes, and the successful filtration was ceased in 4 eyes. The anterior chamber reaction was mild. Hyphema occurred in 1 eye after operation. Intra-operatively, in 4 eyes microperforations occurred in the trabecular meshwork without iris prolapse, and after operation, under the gonioscope, the perforation could be observed in these eyes. In another 2 eyes, there was no intra-operative perforation, but a small fissure was seen by gonioscopy. CONCLUSIONS: NPTS with application of MMC can lower the IOP effectively in this group of patients. The recovery of vision after operation is quick. A few complications occurred after operation. It is a promising technique to treat POAG.

Adolescent↗
PubMed2001

Retinal dystrophy due to paternal isodisomy for chromosome 1 or chromosome 2, with homoallelism for mutations in RPE65 or MERTK, respectively.

Uniparental disomy (UPD) is a rare condition in which a diploid offspring carries a chromosomal pair from a single parent. We now report the first two cases of UPD resulting in retinal degeneration. We identified an apparently homozygous loss-of-function mutation of RPE65 (1p31) in one retinal dystrophy patient and an apparently homozygous loss-of-function mutation of MERTK (2q14.1) in a second retinal dystrophy patient. In both families, the gene defect was present in the patient's heterozygous father but not in the patient's mother. Analysis of haplotypes in each nuclear kindred, by use of DNA polymorphisms distributed along both chromosomal arms, indicated the absence of the maternal allele for all informative markers tested on chromosome 1 in the first patient and on chromosome 2 in the second patient. Our results suggest that retinal degeneration in these individuals is due to apparently complete paternal isodisomy involving reduction to homoallelism for RPE65 or MERTK loss-of-function alleles. Our findings provide evidence for the first time, in the case of chromosome 2, and confirm previous observations, in the case of chromosome 1, that there are no paternally imprinted genes on chromosomes 1 and 2 that have a major effect on phenotype.

Adolescent↗
PubMedDate not supplied

Effects of pulsatile shear stress on signaling mechanisms controlling nitric oxide production, endothelial nitric oxide synthase phosphorylation, and expression in ovine fetoplacental artery endothelial cells.

During gestation, placental blood flow, endothelial nitric oxide (NO) production, and endothelial cell nitric oxide synthase (eNOS) expression are elevated dramatically. Shear stress can induce flow-mediated vasodilation, endothelial NO production, and eNOS expression. Both the activity and expression of eNOS are closely regulated because it is the rate-limiting enzyme essential for NO synthesis. The authors adapted CELLMAX artificial capillary modules to study the effects of pulsatile flow/shear stress on ovine fetoplacental artery endothelial (OFPAE) cell NO production, eNOS expression, and eNOS phosphorylation. This model allows for the adaptation of endothelial cells to low physiological flow environments and thus prolonged shear stresses. The cells were grown to confluence at 3 dynes/cm2, then were exposed to 10, 15, or 25 dynes/cm2 for up to 24 h and NO production, eNOS mRNA, and eNOS protein expression were elevated by shear stress in a graded fashion (p < .05). Production of NO by OFPAE cells exposed to pulsatile shear stress was de novo; i.e., inhibited by L-NMMA (N(G)-monomethyl-L-arginine) and reversed by excess NOS substrate L-arginine. Rises in NO production at 25 dynes/cm2 (8-fold) exceeded (p < .05) that seen for eNOS protein (3.6-fold) or eNOS mRNA (1.5-fold). Acute rises in NO production with shear stress occurred by eNOS activation, whereas prolonged NO rises were via elevations in both eNOS expression and enzyme activation. The authors therefore used Western analysis to investigate the signaling mechanisms underlying pulsatile shear stress-induced increases in eNOS phosphorylation and protein expression by "flow-adapted" OFPAE cells. Increasing shear stress from 3 to 15 dynes/cm2 very rapidly increased eNOS Ser1177, ERK1/2 (extracellular signal-regulated kinase 1 and 2) and Akt, but not p38 MAPK (p38 mitogen-activated protein kinase) phosphorylation by Western analysis. Phosphorylation of eNOS Ser1177 under shear stress was elevated by 20 min, a response that was blocked by PI-3K (phosphatidylinositol 3-kinase) inhibitors wortmannin and LY294002, but not the MEK (MAPK kinase) inhibitor UO126. Basic fibroblast growth factor (bFGF) enhanced eNOS protein levels in static culture via a MEK-mediated mechanism, but it could not further augment the elevated eNOS protein levels induced by 15 dynes/cm2 shear stress. Blocking of either signaling pathways or p38 MAPK did not change the shear stress-induced increase in eNOS protein levels. Therefore, shear stress induced rapid eNOS phosphorylation on Ser1177 in OFPAE cells through a PI-3K-dependent pathway. The bFGF-induced rise in eNOS protein levels in static culture was much less than those observed under flow and was blocked by inhibiting MEK. Prolonged shear stress-stimulated increases in eNOS protein levels were not affected by inhibition of MEK- or PI-3K-mediated pathways. In conclusion, pulsatile shear stress greatly induces NO production by OFPAE cells through the mechanisms of both PI-3K-mediated eNOS activation and elevations in eNOS protein levels; bFGF does not further stimulate eNOS expression under flow condition.

Animals↗