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Biomedical subjects

Jun Han

Publications and source records attributed to Jun Han.

48 records · Page 3Linked to original sources
PubMed2003

[Study on distortion product otoacoustic emissions and expanded high frequency audiometry in noise exposure workers].

OBJECTIVE: To analyse the relationship of distortion product otoacoustic emissions(DPOAE), conventional pure tone audiometry and expanded high frequency audiometry, and discuss the originated mechanism of DPOAE and value in early diagnosis and detection noise-induced deafness. METHOD: DPOAE, conventional pure tone audiometry and expanded high frequency audiometry were performed in 42 young adults with normal hearing of control group and 20 noise exposure workers of test group. DPOAE amplitudes, conventional pure tone hearing thresholds and expanded high frequency hearing thresholds were compared. RESULT: In noise exposure workers against young adults with normal hearing, the pure tone hearing thresholds at 6.0 kHz and expanded high frequency area declined significantly(P < 0.05), DPOAE amplitudes at frequency from 4.0 to 6.0 kHz and 11.2 kHz declined significantly too(P < 0.05), but there existed no significantly difference at frequency from 12.5 to 16.0 kHz between the two groups(P > 0.05). CONCLUSION: DPOAE is potential implement to early diagnose and detect noise-induced deafness. It seems likely that the origination of DPOAE not limited to the outer hair cell in corresponding cochlear area. The originated area and mechanism of DPOAE should be solved by further studies.

Adolescent↗
PubMed2003

[Effect of aging on the ability of growth and differentiation of rat bone marrow stromal cells].

OBJECTIVE: To measure the osteogenesis and adipogenesis potentiality of rat marrow stromal cells (MSCs) derived from 3, 6, 9, 12-month-old doner rats. METHODS: Rat MSCs were induced to osteoblast or adipocyte by osteogenic inducer or adipogenic inducer. In different times, 3 and 12-month-old rat MSCs were observed by histochemistry staining; the mRNA level of type I collagen and lipoprotein lipase of 3, 6, 9, 12-month-old rat MSCs were measured by RT-PCR. RESULTS: The expression of alkaline phosphatase (ALP) of the control group and induced group of 12-month old rat MSCs was less than that of 3-month old rat MSCs after 1-week osteogenic induction. 12 days later, calcification was observed in 3-month old group. Lipid droplets occurred in the cells of 12-month old group after 2-day adipogenic induction, while these droplets occurred after 3-day or 4-day induction in 3-month old group. The mRNA level of type I collagen decreased with the increase of age. The mRNA level of lipoprotein lipase of younger rats was lower than that of older rats. Both of the changes were more significantly with the increase of the induction time. CONCLUSIONS: With the increase of age, the ability of osteogenesis of rat MSCs decreased, but the ability of adipogenesis increased.

Adipose Tissue↗
PubMed2003

[A study on the expression of TGF-beta 1/T beta R II in laryngeal carcinoma].

OBJECTIVE: To explore the expression of TGF-beta 1/T beta R II in laryngeal carcinoma. METHOD: Immunohistochemical study using SP kit in 53 cases. RESULT: The expression of TGF-beta 1 was decreased in carcinoma tissues when compared with peri-cancer controls (P < 0.05). There wasn't difference in T beta R II expression when compared with peri cancer controls (P > 0.05). But it was correlated with the stage, differentiation and lymph node metastasis of laryngeal carcinoma. CONCLUSION: TGF-beta 1/T beta R II may involve in the histogenesis and development of laryngeal carcinoma. The decreased expression of TGF-beta 1/T beta R II may serve as an important molecular marker of laryngeal carcinoma.

Adult↗
PubMed2003

Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation.

OBJECTIVE: The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied. METHODS: Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistance to temperature and UV irradiation were analyzed. A total of 10(6) TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infection. RESULTS: The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4 degrees C, at room temperature (20 degrees C) and at 37 degrees C for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56 degrees C, at 67 degrees C and at 75 degrees C, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level. CONCLUSION: The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.

Environment↗
PubMed2002

Pseudo-MS3 in a MALDI orthogonal quadrupole-time of flight mass spectrometer.

Both the matrix selected and the laser fluence play important roles in MALDI-quadrupole/time of flight (QqTOF) fragmentation processes. "Hot" matrices, such as alpha-cyano4-hydroxycinnamic acid (HCCA), can increase fragmentation in MS spectra. Higher laser fluence also increases fragmentation. Typical peptide fragment ions observed in the QqTOF are a, b, and y ion series, which resemble low-energy CID product ions. This fragmentation may occur in the high-pressure region before the first mass-analyzing quadrupole. Fragment ions can be selected by the first quadrupole (Q1), and further sequenced by conventional MS/MS. This allows pseudo-MS3 experiments to be performed. For peptides of higher molecular weight, pseudo-MS3 can extend the mass range beyond what is usually accessible for sequencing, by allowing one to sequence a fragment ion of lower molecular weight instead of the full-length peptide. Peptides that predominantly show a single product ion after MS/MS yield improved sequence information when this technique is applied. This method was applied to the analysis of an in vitro phosphorylated peptide, where the intact enzymatically-generated peptide showed poor dissociation via MS/MS. Sequencing a fragment ion from the phosphopeptide enabled the phosphorylation site to be unambiguously determined.

Journal Article↗
PubMed2002

Primary culture of porcine pancreatic acinar cells.

INTRODUCTION: The methodology of acinar cell culture has become of primary importance in the research of pancreatic physiology and pharmacology. AIM: To develop a method for primary culture of porcine pancreatic acinar cells. METHODOLOGY: Dispersed pancreatic acinar cells were made by RPMI-1640 medium containing collagenase III. After purification, the isolated acinar cells were cultured in RPMI-1640 medium with 2.5% fetal bovine serum. The morphologic characteristics of acinar cells were described. (3)H-thymidine incorporation of acinar cells and activity of amylase or lipase were determined during the culture. RESULTS: There were no remarkable morphologic changes in the pancreatic acinar cells during the 20-day culture. The acini showed the tendency of gathering but did not attach to the walls of the culture disks. Incorporation of (3)H-thymidine in acinar cells in the primary culture was well kept. The secretion of amylase or lipase from acini decreased with the time of culture. CONCLUSIONS: In the primary culture of acinar cells from porcine pancreas developed in this study, the acinar cells retained normal morphology and ability of growth but not secretion of amylase or lipase. The method would be beneficial for further experiments on acini of porcine pancreas.

Amylases↗
PubMed2002

[Phase III clinical study of a new anticancer drug atofluding].

BACKGROUND & OBJECTIVE: Atofloding (ATFU) is a new derivative of 5-fluorouracil. The phase I and II clinical study have been finished. The current study was a phase III clinical trail of ATFU. The aim of this study was to evaluate the efficacy, toxicity of ATFU combination chemotherapy and compare with ftorafur (FT-207) in patients with gastric cancer, colorectal, esophageal cancer, and liver cancer. METHODS: A multicenter, open randomized controlled trial was carried out. A total of 320 patients with gastric cancer, colorectal, esophageal cancer and liver cancer were randomized into ATFU group (study group) and FT207 group (control group) (a ratio of 2:1), treated with MMC + VP-16 + ATFU (FT-207), DDP + HCPT + ATFU (FT-207), DDP + VDS + ATFU (FT-207), and ADM + MMC + ATFU (FT-207) regimen, respectively. The same dosage of combine drugs were used in the two groups. RESULTS: The response rates of the study group (213 cases) and the control group (107 cases) were 17.1% and 7.9% in gastric cancer (P > 0.05), 16.7% and 9.4% in colorectal cancer (P > 0.05), 20.0% and 24.6% in esophageal cancer (P > 0.05), 5.0% and 9.0% in liver cancer (P > 0.05), respectively. The major adverse effects were mylosuppression and gastrointestinal reactions which frequency and intensity had no statistical difference in the two groups. CONCLUSION: ATFU combination chemotherapy is effective and similar to FT207 in the efficiency and adverse effects for treatment of advanced GI cancers.

Adult↗
PubMed2002

[Osteocalcin and type I collagen mRNA expression of rat marrow stromal cells under induction condition].

OBJECTIVE: To investigate osteocalcin and type I collagen mRNA expression of rat marrow stromal cells under induction condition. METHODS: Cultured rat marrow stromal cells were induced by osteogenic compound(composed of dexamethasone 10(-3) mol/L, beta glyceralphosphate 10 mmol/L, ascorbic acid 50 micrograms/ml). Osteocalcin and type I collagen mRNA expression were measured using RT-PCR technique. RESULTS: It was found that rat marrow stromal cells in induced group have an increased time-dependent expression of osteocalcin and type I collagen mRNA, in comparison with control groups. And the necessity of 1,25-(OH)2D3 in induced osteocalcin mRNA expression was confirmed. CONCLUSION: The cultured rat marrow stromal cells kept the undifferentiated state and had osteogenic potential testified by increased osteocalcin and type I collagen mRNA expression when induced.

Animals↗
PubMed2001

[Fetal Bone Marrow Stromal Cells in Cooperation with Exogenous Cytokines Support In Vitro Expansion of Cord Blood CD34(+) Cells]

To elucidate the role of fetal bone marrow stromal cells (FBMSC) in cooperation with exogenous cytokines in supporting the in vitro expansion of cord blood CD34(+) cells which were purified by negative immunomagnetic selection, FBMSCs were cultured with different combinations of cytokines including SCF, IL-3, IL-6, FL, G-CSF and EPO in a 14-day liquid culture system. The results showed FBMSC plus SCF, IL-3, IL-6, FL and EPO was the most effective combination which increased total nucleated cells, CFU-GM, BFU-E and CD34(+) cells by (692.4 +/- 52.7) fold, (237.1 +/- 106.6) fold, (114.8 +/- 32.8) fold and (25.3 +/- 10.1) fold, respectively. Our studies indicated that fetal bone marrow stromal cells combined with above-mentioned cytokines can efficiently expand cord blood CD34(+) cells.

Journal Article↗
PubMedDate not supplied

Proteolysis and mass spectrometric analysis of an integral membrane: aquaporin 0.

Due to hydrophobicity, structural analysis of integral membrane proteins poses a formidable challenge for current mass spectrometry-based proteomics approaches. Herein, we demonstrate results from optimized sample preparation and enzymatic proteolysis procedures for the complete primary structure determination of a targeted integral membrane protein, lens aquaporin 0 (AQP0). Plasma membrane from bovine lens tissue was alkali treated and tryptic digestion was performed in optimized acetonitrile-ammonium bicarbonate solution. Full sequence coverage of AQP0 was observed as tryptic peptides using both matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and capillary liquid chromatography tandem mass spectrometry (cLC/MS/MS). An amino acid mutation of Thr to Ile/Leu at residue 199 was deduced based on MS/MS results. In a complementary effort to fully sequence the protein, peptic digestion was developed to take advantage of hydrophobic protein solubility in organic acid as well as the decreased activity of pepsin at low pH. Peptic digestion in 10% formic acid (pH 1.2) generated peptides of 500 to 3000 Da and gave 100% sequence coverage by cLC/MS/MS. In addition to post-translational modifications reported previously, a new phosphorylation site at serine 229 and two oxidation sites at tryptophan 202 and 205 were detected on the protein. These methodologies provide complementary detergent- and CNBr-free procedures for detailed analysis of this important membrane channel protein and offer promise for analysis of the integral membrane proteome.

Amino Acid Sequence↗