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Biomedical subjects

Ping Chen

Publications and source records attributed to Ping Chen.

At least 181 records · Page 10Linked to original sources
PubMed2003

[The damaged types of eustachian tube function in the patients of nasopharyngeal carcinoma after radiotherapy].

OBJECTIVE: To study the types and the influences of eustachian tube function disorder in the patients of nasopharyngeal carcinoma(NPC) after radiotherapy. METHOD: Thirty-two patients of NPC (50 ears) that the eustachian tube function were damaged after radiotherapy were examined by general examination, audiometer test, tympanometry, Tubo-tymanoaerodynamic grapy (TTAG), sonotubometry and endoscope. RESULT: Two cases (4 ears) showed abnormal patency of eustachian tube, the patients' symptoms were lightly. The eustachian tube adhesion were found in five patients(7 ears), and 17 patients(27 ears) showed eustachian tube complete obstruction, eight patients (12 ears) showed eustachian tube uncompleted obstruction, they had the similitude symptoms. CONCLUSION: The damaged types of eustachian tube function in patients of NPC after radiotherapy are different, it will harm the ear function. Finding it out will help to choose the treating measures.

Adult↗
PubMed2003

Etiology and surgical treatment of hilar bile duct stricture.

OBJECTIVE: To improve the surgical effects of hilar duct stricture. METHODS: The clinical data of 76 patients with hilar bile duct stricture treated at our hospital from 1990 to 2000 were analyzed. The diagnosis was determined by triad signs of cholangitis, increase of ALP and gamma-GGT levels, dilation of intrahepatic and extrahepatic bile ducts confirmed by ultrasonography (US), computed tomography (CT), percutaneous transhepatic cholangiography (PTC) or endoscopic retrograde cholangiopancreatography (ERCP). The location of stricture was divided according to the Bismuth classification standard. RESULTS: Among the 76 patients, 46 (60.5%) suffered from injurious stricture, including 13% of Bismuth type I, 39% of type II, 19.4% of type III, and 28.2% of type IV. Inflammatory stricture was found in 28 patients, locating in the left hepatic duct (LHD) 46.4% (13/28), the right hepatic duct (RHD) 35.7% (10/28), and the common hepatic duct (CHD) 17.9% (5/28), respectively. The percentages of patients with stricture due to Mirizzi's syndrome, bile duct cyst, and sclerosing cholangitis were 9.2%, 3.9% and 2.6%, respectively. Bile duct repair procedures included biliary reconstruction with pedicled umbilical vein graft for 9.2% of the patients, and proximal cholangiojejunostomy combined with LHD and RHD plasticity for 92.2%. Seventy of the 76 patients were followed up for 2-10 years, and the excellent outcome rate was 94.7%. CONCLUSIONS: Injurious stricture is the major type of hilar bile duct stricture. Inflammatory stricture is mainly composed of RHD. Hilar bile duct stricture should be treated surgically according to various etiological features and technical principles of biliary repair.

Adult↗
PubMed2003

Selectively enhanced sensitivity of bronchoalveolar lavage fluid (BALF) mast cells to IgE dependent stimulation in mild asthmatics.

The aim of this study is to investigate the histamine-releasing ability of mast cells from asthmatic bronchoalveolar lavage fluid (BALF). Following the measurement of the forced expiratory volume at the first second (FEV1), 29 mild asthmatics were included in the study and were subjected to fibreoptic bronchoscopy. The cells recovered from the BALF were challenged with anti-IgE, calcium ionophore A23187 (CI) or adenosine, and the released histamine was measured with an enzyme-linked chromogenic assay. Enzymatically dispersed mast cells from human lung or colon tissues were employed as control groups. The results showed that mast cells from BALF were at least 100 fold more sensitive to anti-IgE than those from lung or colon tissues. However, there was little difference between mast cells from BALF, lung or colon tissues in response to CI. Adenosine failed to stimulate histamine release from BALF mast cells. In conclusion, asthmatic BALF mast cells are much more sensitive to IgE-dependent stimulation than the non-IgE-dependent ones, indicating that mast cells may play a role in the pathogenesis of asthma.

Adenosine↗
PubMed2003

[Mid- to long-term effects of delayed percutaneous coronary intervention on left ventricular function and prognosis in patients with acute myocardial infarction].

OBJECTIVE: To investigate the mid- to long-term effects of delayed percutaneous coronary intervention (PCI) on the left ventricular function and clinical outcome of patients with acute myocardial infarction (AMI). METHODS: PCI (including percutaneous transluminal coronary angioplasty and stenting) was performed in 42 patients within 1 to 2 weeks following the onset of AMI (PCI group), with another 31 patients who were admitted within the same period to receive medication for AMI serving as the control group. The patients in both groups were observed for comparison of the occurrence of reinfarction and angina, mortality at 1 and 6 months, and findings by ultrasound cardiograms (UCG). RESULTS: In PCI group, the left ventricular function were obviously improved as compared with the control group (P<0.01) 1 month after the onset of AMI, showing greater improvement at 6 months (P<0.01). No death or reinfarction occurred in the PCI group, with only 1 patients experiencing angina 5 months after PCI. In control group, death occurred in 2 cases, reinfarction in 1 case, recurrent angina in 4 cases (include 2 cases of early postinfarction angina). CONCLUSION: Delayed PCI may significantly improve the prognosis of patients with AMI and prolong their survival without cardiovascular accidents and ameliorate their left ventricular functions, with high success rate of the operation.

Adult↗
PubMed2003

[Effect of surfactant on sorption of polar organic compounds in sediment].

Partition characters of phenol, aniline and p-nitrophenol in sediment-anionic surfactant sodium dodecylbenzene sulfonate(SDBS) system were researched. The results indicated that that the sediment-water partition coefficients K of aniline and p-nitrophenol increased when the initial concentrations were set at 200 mg/L and 1200 mg/L for SDBS. The positive relation was found between partition enhancement and the KOW the of the organic compounds. But the K of phenol was different from that of aniline and p-nitrophenol in SDBS system with initial concentration set for 1200 mg/L and it was lower than that in pure water. The data showed that in sodium dodecyl sulfate (SDS), Triton X-100 (TX100) and Brij30 systems respectively, the sorption of phenol on the sediment was enhanced by surfactants below their critical micelle concentration(CMCs), but it was diminished above the surfactant CMCs.

Adsorption↗
PubMed2003

Association of vitamin A and zinc status with altered intestinal permeability: analyses of cohort data from northeastern Brazil.

To examine the association of intestinal barrier function with vitamin A deficiency and whether supplementation of micronutrients improves intestinal function and/or linear growth, height-for-age z-score (HAZ), concentrations of serum retinol and zinc, and intestinal permeability were determined in a cross-sectional sample of 75 children in northeastern Brazil. Effects of vitamin A and supplementation of zinc on intestinal permeability and growth were also determined comparing results before and after treatment in 20 children and age-matched controls. Lactulose:mannitol (L/M) permeability ratios inversely correlated with serum retinol concentrations (r = -0.55, p < 0.0005). Increased L/M permeability ratios with reduced concentrations of serum retinol were predominantly attributable to lower absorption of mannitol (r = 0.28, p = 0.02). L/M permeability ratios (p = 0.001) and HAZ scores (p = 0.007) improved with supplementation. It is concluded that impaired intestinal barrier function and linear growth shortfalls improve following supplementation of vitamin A and zinc in this setting.

Brazil↗
PubMed2003

[Effect of adenosine and anti-IgE antibody on histamine release from mast cells in BALF of asthma patients].

AIM: To investigate the functional properties of mast cells in bronchoalveolar lavage fluid (BALF) of asthma patients. METHODS: 29 asthma patients in the recovery phase were enrolled in the study and their bronchoalveolar lavages (BAL) were inspected under fibreoptics bronchoscope. The cells from each BAL fluid(BALF) were added to LP4 tubes containing anti-IgE antibody, adenosine, buffer or anti-IgE antibody + adenosine, and incubated at 37 degrees C for 20 min. The reactions were stopped by placing the tubes on ice and adding 100 microL of cold incomplete Hank's balanced salt solution (HBSS). The histamine chromogenic assay was performed to detect histamine released from mast cells in BALF. Histamine release was expressed in a net release percentage. RESULTS: 100 micromol/L of adenosine failed to induce histamine release from mast cells; while 1,000 micromol/L of adenosine could induce about 17% histamine release from mast cells in BALF; For anti-IgE antibody, as low as 1 x 10(-4) g/L of anti-IgE was able to induce approximately 20% histamine release from the mast cells. When the anti-IgE antibody was combined with adenosine, only 3 x 10(-5) g/L of anti-IgE antibody + adenosine could exert synergistic effectiveness. CONCLUSION: Mast cells in BALF from asthma patients had a poor reaction to adenosine stimulation,but are much more sensitive to anti-IgE antibody-dependent stimulation; only as low as 3 x 10(-5) g/L of anti-IgE antibody is able to cooperate with adenosine.

Adenosine↗
PubMed2002

Purification of long-chain fatty acid ester of epigallocatechin-3-O-gallate by high-speed counter-current chromatography.

Epigallocatechin-3-O-gallate (EGCG) was modified by catalytic esterification with hexadecanoyl chloride. A long-chain fatty acid ester derivative was obtained from the purification of this reaction product by high-speedcounter-current chromatography using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v). The structure of the derivative, epigallocatechin-3-O-gallate-4'-hexadecanate, was elucidated by IR, MS and 1H NMR.

Catechin↗
PubMed2002

Molecular cloning and characterization of protein phosphatase 2C of vomeronasal sensory epithelium of garter snakes.

The earthworm-derived chemoattractant ES20 interacts with its G-protein-coupled receptors on the plasma membrane of vomeronasal (VN) sensory neurons of garter snakes, resulting in an increase in inositol trisphosphate [J. Biol. Chem. 269 (1994) 16867] and a rapid phosphorylation of the membrane-bound proteins, p42/44 [Biochim. Biophys. Acta 1450 (1999) 320]. The phosphorylation of p42/44 proteins are countervailingly regulated by a protein kinase and an okadaic acid-insensitive but fluoride-sensitive protein phosphatase (PPase) [J. Liu et al. (loc. cit.)]. The phosphorylation of p42/44 induced by ES20 appears to play a role in the regulation of signal transduction pathways by modulating the GTPase activity [J. Liu et al. (loc. cit.)]. A 564-bp fragment of cDNA was obtained from VN RNA of garter snakes by reverse transcription polymerase chain reaction with degenerate primers. The 564-bp fragment was amplified, cloned, and sequenced. Northern blot analysis revealed that both the VN organ (VNO) and brain contained the gene of PPase 2C. A full-length complementary 4119-bp DNA containing an open reading frame of 1146bp that encodes a protein of 382 amino acids with a molecular mass of 49,123Da was obtained from the VN cDNA library of garter snakes. The deduced amino acid sequence showed 88% amino acid identity to bovine protein phosphatase 2C alpha and 87% identity to human and rat PP2C alpha and to Mg(2+)-dependent protein phosphatase 1A of rat and rabbit. In situ hybridization revealed that the mRNA of VN protein phosphatase 2C is expressed in the vomeronasal sensory epithelium. This is the first report of the identification of a type 2C serine/threonine protein phosphatase in the VN system.

Amino Acid Sequence↗
PubMed2002

Interaction of hydrogen with metal nitrides and imides.

The pursuit of a clean and healthy environment has stimulated much effort in the development of technologies for the utilization of hydrogen-based energy. A critical issue is the need for practical systems for hydrogen storage, a problem that remains unresolved after several decades of exploration. In this context, the possibility of storing hydrogen in advanced carbon materials has generated considerable interest. But confirmation and a mechanistic understanding of the hydrogen-storage capabilities of these materials still require much work. Our previously published work on hydrogen uptake by alkali-doped carbon nanotubes cannot be reproduced by others. It was realized by us and also demonstrated by Pinkerton et al. that most of the weight gain was due to moisture, which the alkali oxide picked up from the atmosphere. Here we describe a different material system, lithium nitride, which shows potential as a hydrogen storage medium. Lithium nitride is usually employed as an electrode, or as a starting material for the synthesis of binary or ternary nitrides. Using a variety of techniques, we demonstrate that this compound can also reversibly take up large amounts of hydrogen. Although the temperature required to release the hydrogen at usable pressures is too high for practical application of the present material, we suggest that more investigations are needed, as the metal-N-H system could prove to be a promising route to reversible hydrogen storage.

Journal Article↗
PubMed2002

C-3 Amido-indole cannabinoid receptor modulators.

C-3 Amido-indoles were found to selectively bind to the CB2 receptor. SAR studies led to optimized compounds with excellent in vivo potency against LPS induced TNF-alpha release in murine models of cytokine production.

Amides↗
PubMed2002

[BRCA2 gene mutation detection in hereditary ovarian cancer tissues].

OBJECTIVE: The aim of this study was to detect the mutation of BRCA2 gene in hereditary ovarian cancer tissues to probe the clinical significance of it. METHODS: DNA was abstract from paraffin embedded tissues archived in pathology department. A pair of primer located on 11 exon was used to detect the 6174 delT mutation,BRCA2 gene mutation in 12 hereditary ovarian cancer patients and 15 sporadic ovarian cancer patients were screened by polymerase chain reaction-single strand conformation polymorphism analysis with DNA non- isotopic silver staining methods. RESULTS: Two of 12 hereditary ovarian cancer victims were found carrying mutation of BRCA2 gene. The mutation type was 6174del T in the 11 exon of BRCA2 gene. No mutation of BRCA2 gene on this site was found in 15 sporadic ovarian cancer patients. CONCLUSION: BRCA2 gene mutation was closely associated with the carcinogenesis and development of hereditary ovarian cancer, but had no relationship with sporadic ovarian cancer.

Female↗
PubMed2002

Quantification of cholesterol in foods using non-aqueous capillary electrophoresis.

A simple method for the rapid quantification of cholesterol in egg yolk and milk by non-aqueous capillary electrophoresis (NACE) is described in this paper. The samples were treated with saponification and then quantified by NACE, in which 100 mM sodium acetate-acetic acid in methanol was employed as the running buffer. The correlation coefficient between the cholesterol concentration and the corresponding peak area was 0.999. The detection limit of cholesterol was 5 microg/ml (twice the signal-to-noise ratio). This method can be used as a routine method for the rapid and sensitive determination of cholesterol in foods.

Calibration↗
PubMed2002

Determination of substrate motifs for human Chk1 and hCds1/Chk2 by the oriented peptide library approach.

Mammalian Chk1 and Chk2 are two Ser/Thr effector kinases that play critical roles in DNA damage-activated cell cycle checkpoint signaling pathways downstream of ataxia telangiectasia-mutated and ataxia telangiectasia-related. Endogenous substrates have been identified for human hCds1/Chk2 and Chk1; however, the sequences surrounding the substrate residues appear unrelated, and consensus substrate motifs for the two Ser/Thr kinases remain unknown. We have utilized peptide library analyses to develop specific, highly preferred substrate motifs for hCds1/Chk2 and Chk1. The optimal motifs are similar for both kinases and most closely resemble the previously identified Chk1 and hCds1/Chk2 substrate target sequences in Cdc25C and Cdc25A, the regulation of which plays an important role in S and G(2)M arrest. Essential residues required for the definition of the optimal motifs were also identified. Utilization of the peptides to assay the substrate specificities and catalytic activities of Chk1 and hCds1/Chk2 revealed substantial differences between the two Ser/Thr kinases. Structural modeling analyses of the peptides into the Chk1 catalytic cleft were consistent with Chk1 kinase assays defining substrate suitability. The library-derived substrate preferences were applied in a genome-wide search program, revealing novel targets that might serve as substrates for hCds1/Chk2 or Chk1 kinase activity.

Amino Acid Sequence↗