PubMed Health⌕ Search

Biomedical subjects

Peng Yang

Publications and source records attributed to Peng Yang.

34 records · Page 2Linked to original sources
PubMed2005

Thickness measurement of nanoscale polymer layer on polymer substrates by attenuated total reflection infrared spectroscopy.

For the first time, attenuated total reflection (ATR)-Fourier transform infrared (FT-IR) spectroscopy was utilized to measure the thickness (d0) of a nanoscale polymer layer on polymer substrate with significant credibility. First, a mathematical formula, A/A0 = 1 - 2d0/ d(p), was derived based on a self-defining subsection function (where d(p) was defined as depth of penetration of ATR and A and A0 were defined as the absorption band area of the characteristic functional group only contained in bulk substrate with a thin polymer layer attachment and the same group in blank substrate, respectively). On the mathematical model, through changing incidence angles, a series of values of A (A0) and corresponding d(p) were obtained, and when plotting A/A0 versus 2/d(p), d0 was obtained as the slope. With polystyrene (coating)/olypropylene (substrate) as a model system, we obtained the relevant values (d0). Comparing the results with the values of practical coating thickness (calculation and TEM observation), we found that this method was able to characterize well the thickness of a thin polymer layer on a polymer substrate in the range from 10 to 110 nm. Errors in the measurement were given and analyzed. Furthermore, this method was well applied in the thickness measurement of a polyacrylamide graft layer on a polypropylene film surface. The effect of pressure in the ATR technique on the coating thickness measurement was also discussed. In comparison with other methods such as XPS, SEM, TEM, and AFM, this approach based on a universal ATR technique was very convenient and fast. This method is expected to widen the application of the ATR-FT-IR technique and stimulate the further development of many fields such as surface self-assembly and surface functionlization.

Journal Article↗
PubMed2005

Biomimetic synthesis silver crystallite by peptide AYSSGAPPMPPF immobilized on PET film in vitro.

AG3 (AYSSGAPPMPPF) is an inorganic-binding peptide that specifically and selectively binds to silver demonstrated by phage display library according to the Stone group. In our experiment, synthesized silver-binding peptide AG3 was immobilized on the surface of protonated poly(ethylene terephthalate) (PET) film which was prepared for biomimetic synthesis silver particles in vitro. Silver crystallites formatted on the surface of AG3-PET film showed various shapes and was 1-4 microm in size. In addition to hexagonal and triangular crystallite, a silver crystallite presents a cubical shape that has seldom been reported in the literatures so far. With comparison of the control and silver nitrate salt, the surface energy of the silver particles on AG3-PET film surface XPS analysis suggested that Ag+ was being reduced to Ag0 in the reaction. Moreover, CD spectrum revealed that the secondary structure of AG3 peptide in solution had a little change before and after binding silver.

Amino Acid Sequence↗
PubMed2005

[Treatment of non-small-cell lung cancer with paraplatin given by two different dosage calculation methods].

OBJECTIVE: To study the reasonable dosage for paraplatin according to different dosage calculations. METHODS: A prospective, randomized, single-blinded study on 54 patients with advanced non-small-cell lung cancer (NSCLC) treated with paraplatin was conducted. Patients were divided to 2 groups. In group A, paraplatin dosage was calculated according to patients' body surface, and in group B, it was calculated according to the area under the curve (AUS). Hematological toxicity, response rate and survival rate in the two groups of patients were compared. RESULTS: Neutropenia in group A and group B was seen in 77.8% and 37.0% (P < 0.05), and thrombocytopenia in 18.5% and 3.7% (P > 0.05) of patients, respectively. Hemoglobin decrease was seen in 48.2% of patients in both groups. The average quantity of paraplatin given in one cycle of treatment was 535.93 +/- 106.71 mg and 398.52 +/- 71.72 mg (P < 0.01) respectively. The average time interval between treatment cycles was 27.04 +/- 5.30 d and 22.85 +/- 2.80 d (P < 0.05). The response rate and survival rate of patients in group A and B were 22.2% versus 48.2% (P < 0.05), and 40.7% versus 44.4% (P > 0.05) respectively, but the median survival time was identical (12 months) in the two groups. CONCLUSION: NSCLC patients given paraplatin with dosages calculated on the basis of AUC have higher response rate and less severe hematological toxicity than those given paraplatin with dosages on the basis of body surface. However, the median survival time and survival rate have no statistical differences between the two groups of patients.

Adenocarcinoma↗
PubMed2005

[Achievement of the noninvasive measurement for human blood glucose with NIR diffusion reflectance spectrum method].

The noninvasive measurement of human blood glucose was achieved with NIR diffusion reflectance spectrum method. The thumb fingertip NIR diffusion reflectance spectra of six different age healthy volunteers were collected using Nexus-870 and its NIR fiber port smart accessory. The test was implemented with changing the blood glucose concentration for the limosis and satiation of every volunteer. The calibration model was set up using PLS method with the smoothing, baseline correction and first derivatives pretreatment spectrum in the 7500-8500 cm(-1) region for single volunteer, the same age combination and that of different age. When the spectrum was obtained, the actual blood glucose value of every spectrun sample was demarcated using ultraviolet spectrophotometer. The correlation between the calibration value and true value for single volunteer is better than that for the combination of volunteers, the correlative coefficients are all over 0.90471, RMSECs are all less than 0.171.

Adult↗
PubMed2005

[Feasibility of thoracoscopic pulmonary metastasectomy].

BACKGROUND & OBJECTIVE: With the developments in endoscopic surgery and the advances of radiological techniques, thoracoscopic pulmonary metastasectomy has been used more and more widely. This study was to evaluate the feasibility of thoracoscopic resection of pulmonary metastases. METHODS: The clinical data of 17 patients who underwent thoracoscopic pulmonary metastasectomy were retrospectively analyzed. RESULTS: All pulmonary metastases in the 17 patients were peripherally located and encountered during follow-up after treatment of primary disease. Metastases at other sites were excluded. Among the 17 cases of metastases, 10 were solitary metastasis, 4 were unilateral multiple metastases, 3 were bilateral metastases. All patients underwent thoracoscopic wedge resection. No major complications, operative mortality, and port site metastasis presented. Postoperative locoregional relapse occurred in 5 patients, in which 4 patients had multiple metastases, the rest 1 patient with soft tissue sarcoma underwent a second thoracoscopic resection of recurrent pulmonary lesion. The 1-, 3-, and 5-year survival rates were 77.3%, 53.1%, and 34.8%, respectively. CONCLUSIONS: Thoracoscopic resection is feasible and effective for patients with a solitary pulmonary metastasis, especially when the lesion is smaller than 3 cm and peripherally located. Bilateral pulmonary metastases may also be resected by primary thoracoscopic operation.

Adult↗
PubMed2005

[Synthesis and insulinotropic activity of 2-benzylidenesuccinic acid derivatives].

AIM: To design and synthesize new compounds of prandial glucose regulator with more simple structure. METHODS: The target compounds were synthesized from diethyl succinate and benzaldehyde or 4-fluorobenzaldehyde by four-step reactions. Thus 18 compounds were synthesized. Their structures were comfirmed by NMR, MS and IR. RESULTS: Seventeen compounds had different hypoglycemic activity in mice, among them, 9 compounds had higher hypoglycemic activity and 6 compounds had character of prandial glucose regulator. CONCLUSION: Part of the compounds have higher hypoglycemic activity deserve to be further investigated.

Animals↗
PubMed2004

Expression and clinical significance of p27kip1 protein in primary liver cancer.

To investigate the expression and clinical significance of p27kip1 protein in primary liver cancer, the expression of p27kip1 protein and the relationship with clinicopathological factors were studied in primary liver cancer by using SABC immunohistochemical staining in specimens of 40 cases of primary liver cancer and 20 cases of liver cirrihosis. Our results showed that positive expression rate of p27kip1 protein in primary liver cancer was 37.5% (15/40), which was lower than that in benign lesion of liver 80.0% (16/20, P<0.01). The expression level of p27kip1 protein in primary liver cancer showed significant differences in tumor size, Edmonson histological grade, portal invasion, lymph node metastasis, TNM stage (P<0.05, for all), but not significantly correlated with patient's age and histological types. Log rank test showed that the p27kip1 expression was significantly related with prognosis of the patients (P<0.05), and the prognosis of the patients with p27kip1 positive expression was markedly better than that of those with p27kip1 negative expression. It is concluded that the expression of p27kip1 was significantly related clinicopathological factors of primary liver cancer. p27kip1 protein may be used as a novel tumor marker for primary liver cancer.

Adult↗
PubMed2004

[Evaluation of operation and anesthesia on hemodynamic variables in patients undergoing elective abdominal surgery by noninvasive thoracic bioimpedance technique].

OBJECTIVE: To analyse and discuss the effects of elective abdominal operation and anaesthesia on patients' cardiac output via noninvasive thoracic bioimpedance technique. METHODS: Noninvasive monitoring system HeMo-601 was applied to detect the hemodynamic variables of 32 elective abdominal surgery patients. The clinical data of cardiac output (CO), cardiac index (CI), cardiac working per minute (CW), left ventricular end-diastolic pressure (LVEDP), stroke volume (SV), cardiac stroke working (SW) and heart rate (HR) were analysed at 1 hour before operation, 4-6 hours after operation and 24 hours after operation, respectively. RESULTS: No significant differences were found in CO, CI, CW and LVEDP between various time points and preoperation (all P>0.05). SV and SW at 4-6 hours after operation were significant lower than those before operation (all P<0.05). Whereas, SV and SW at 24 hours after operation were no significant differences compared with those before operation (all P>0.05). As compared with preoperation, HR at 4-6 hours after operation was significantly faster (P<0.05). However, there was no significant difference in HR between 24 hours after operation and preoperation (P>0.05). CONCLUSION: The reductions in SV and SW at 4-6 hours after operation might be a result of anaesthesia that could weaken the contraction of heart. The presence of rapidness of HR at 4-6 hours after operation might be a compensatory mechanism for the decreases in SV and SW. Therefore, optimizing adequate infusion by the greatest extent during and after operation is very crucial for the maintenance of CO, CI and tissue perfusion.

Abdomen↗
PubMed2004

[Clinical analysis of complications after non- invasive positive pressure ventilation and an inquiry into the respiratory treatment strategy in patients with SARS].

OBJECTIVE: To analyze the clinical data of severe acute respiratory syndrome (SARS) patients with pneumothorax and mediastinal emphysema occurring after the non-invasive positive pressure ventilation (NIPPV), and to inquire into relevant strategy in respiratory treatment in the SARS patients. METHODS: Twenty-seven serious cases of SARS undergone NIPPV were analyzed retrospectively. RESULTS: Pneumothorax and mediastinal emphysema occurred in 7 of 27 serious cases of SARS with NIPPV, and mediastinal emphysema occurred in 1 of 189 cases of SARS without mechanical ventilation (MV). The incidence of pneumothorax and mediastinal emphysema in serious cases of SARS with NIPPV was significantly higher (chi2=25.052, P<0.01) than that in cases of SARS without receiving MV. The peripheral blood oxygen saturation level was not changed significantly after reasonable adjustment of ventilation pressure and increase in oxygen concentration inhaled. Seven cases of pneumothorax and mediastinal emphysema improved gradually. CONCLUSION: The incidence of pneumothorax and mediastinal emphysema in serious SARS patients with NIPPV is significantly higher than that in SARS patients without receiving MV. This might be related to SARS related pulmonary injuries, intensive cough and high mechanical ventilation pressure. The pneumothorax and mediastinal emphysema improve gradually in all cases after reasonable adjustment of mechanical ventilative pressure. So when NIPPV is used in the treatment of serious SARS patients to improve hypoxemia, optimized mechanical ventilative pressure should be acquired in order to avoid pneumothorax and mediastinal emphysema.

Adult↗
PubMed2004

[Effects of hydrocortisone on oxygen free radicals released by polymorphonuclear neutrophils in lipopolysaccharide-induced acute lung injury in mice].

BACKGROUND: Corticosteroid treatment of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) has been one of the most controversial clinical issues in critical care. Although the administration of high-dose corticosteroids does not benefit patients with early septic shock and ARDS, recent clinical trials have indicated that treatment with relatively low-dose corticosteroids (2 to 3 mg/kg/day of methylprednisolone or equivalent) may improve outcome when used for late ARDS or persistent septic shock. The underlying mechanism was not fully clarified. Whether the administration of corticosteroids can arrest neutrophil-driven organ injury once started remains to be elucidated. OBJECTIVE: To observe the effects of hydrocortisone (HC, 6 mg/kg) on oxygen free radicals (OFR) released by PMN and pulmonary pathological changes in rat ALI model induced by lipopolysaccharide (LPS), to investigate the possible mechanism through which corticosteroids exert protective effect on ALI. METHODS: A rat model of ALI was induced by peritoneal injection of 2 x 10(12) Escherichia coli/kg. Fifty-six rats were randomly divided into three groups: normal control group, LPS group and HC group (6 mg/kg). Samples were collected 2 h, 4 h and 6 h after giving LPS to LPS and HC group (6 h after giving normal saline in normal control group) to measure the level of OFR released by PMN using chemiluminescence method based on lumino, and to compae of pulmonary pathological changes among the three groups. RESULTS: Pathological examination with light microscope in LPS group showed thickened pulmonary interstitia, inflammatory cell infiltration, edema and hemorrhage, which were in accordance with the features of ALI. There were significant differences in the release of OFR by PMN among the three groups (P < 0.01). The level of OFR released by PMN in LPS group was significantly higher than that of the control group, and continued to increase during the observation period (2 - 6 h after LPS). The release of OFR by PMN in HC group was significantly suppressed as compared with LPS group, which was peaked at 4 h after LPS injection (to 98.2%); there were also significant differences in the grades of ALI pathologic changes among the three groups (P < 0.01). The grades of ALI pathologic changes in LPS group were significantly increased when compared with the normal control group (P < 0.05) while significantly decreased in HC group as compared with LPS group (P < 0.05). CONCLUSION: It was demonstrated in the LPS induced ALI model that OFR might play an important role in onset of ALI. Intervening with HC (6 mg/kg) treatment could ameliorate the lung injury and exert significant and sustained suppression on the release of OFR by PMN, showing that HC has a protective effect on LPS induced ALI and its theraputic effect occurs possibly through suppression on the release of OFR by PMN.

Acute Lung Injury↗
PubMed2004

[Microwave assisted UV electrodeless discharge lamp photochemical degradation of 4-chlorophenol in aquatic solutions].

A microwave assisted UV electrodeless discharge lamp system (MW/UV) was used for photo-degradation of 4CP simulated wastewater. In order to evaluate the degradation efficiency of 4CP, UV spectrophotometry and ion chromatography were used for determination of 4CP and Cl- respectively. The degradation rate in MW/UV system was higher than that in the UV system within 120min, which were 52.40% and 21.56% respectively. The degradation efficiency was improved by increasing pH value of the solution, aerating O2 gas, enhancing light intensity, or adding H2O2 oxidant. The degradation of 4CP under MW/UV accords with the first order kinetics equation.

Chlorophenols↗
PubMed2004

[Applying competitive polymerase chain reaction to the detection of hepatitis B virus DNA].

OBJECTIVE: To reduce the rate of accidental false negative result in the HBV DNA PCR test on clinical serum samples. METHODS: A competitive polymerase chain reaction (C-PCR) was used to decrease the false negative ratio. In the C-PCR, a constructed inner control DNA was added for co-amplification with the HBV target DNA. RESULTS: In a 20 microl C-PCR system, about 60 to 200 copies of inner control DNA could give apparent co-amplification signal band after electrophoresis on a 2% agarose gel. Five of 120 samples of clinical serum (4.2%) could not be amplified. CONCLUSION: C-PCR has the advantage of yielding information on false negative in the HBV DNA PCR assay of clinical serum samples.

DNA, Viral↗
PubMed2003

BioEditor-simplifying macromolecular structure annotation.

SUMMARY: BioEditor is an application to enable scientists and educators to prepare and present structure annotations containing formatted text, graphics, sequence data, and interactive molecular views. It is intended to bridge the gap between printed journal articles and Internet presentation formats. BioEditor is relevant in the era of structural genomics, where annotation and publication could become the rate determining step in structure determination. AVAILABILITY: BioEditor is available at http://bioeditor.sdsc.edu. The Web site includes the latest version of the software for Microsoft Windows, including documentation, the opportunity to submit bug reports and suggestions, example documentaries prepared with BioEditor and a repository where users can submit documentaries for posting to the site.

Biopolymers↗
PubMed2002

Differential lineage restriction of rat retinal progenitor cells in vitro and in vivo.

To identify and characterize the lineage potential of rat neural retina progenitor cells (NRPCs) in vitro and engrafted into rats with retinal degeneration, NRPCs were isolated from neural retinas of embryonic day 17 Long Evans rats and cultured in serum-free or serum-containing media with fibroblast growth factor 2 and neurotrophin 3. After expansion, cellular differentiation was initiated by the withdrawal of these growth factors. Despite forming primary neurospheres, NRPCs cultured in serum-free medium survived poorly after passage. In contrast, NRPCs cultured in serum-containing medium could be expanded for up to 12 passages and differentiated into glial fibrillary acidic protein-positive glial cells and retina-specific neurons expressing rhodopsin, S-antigen, calbindin, recoverin, and calretinin. For in vivo analysis, passage 1 (P1) undifferentiated NRPCs were labeled with bromodeoxyuridine (BrdU), implanted into the subretinal space of Royal College of Surgeons (RCS) rats, and analyzed immunohistochemically 4 weeks postgrafting. The grafted NRPCs showed extensive glial differentiation, irrespective of their topographic localization. A few BrdU-labeled grafted NRPCs expressed protein kinase C, a marker for bipolar and amacrine interneuron-specific differentiation. Other retina-specific or oligodendrocytic differentiation was not detected in the grafted cells. Although NRPCs are capable of self-renewal and multilineage differentiation in vitro, they developed mostly into glial cells following engraftment into the adult retina. These data suggest that the adult retina retains epigenetic signals that are either restrictive for neuronal differentiation or instructive for glial differentiation. Induction of lineage-specific cell differentiation of engrafted NRPCs to facilitate retinal repair will likely require initiation of specific differentiation in vitro prior to grafting and/or modification of the host environment concomitantly with NRPC grafting.

Animals↗
PubMed2002

In vitro isolation and expansion of human retinal progenitor cells.

Human retinal development proceeds with temporal and spatial precision. Although differentiation starts around the beginning of the third month of gestation, the majority of cells in the outer neuroblastic layer of human neural retina are still proliferating, as evidenced by their Ki-67 immunoreactivity. In the present study, the proliferating human retinal progenitor cells (HRPCs) were isolated and expanded in culture. They were capable of dividing for multiple generations (with passage 8, the latest tested) and differentiating to several retinal cell phenotypes. These findings indicate that human retina at the 10th-13th week of gestation harbors progenitor cells that can be maintained and expanded in vitro for multiple generations. The availability of such cells may have important implications with respect to human degenerative retinal diseases, as these HRPCs have the potential to be used therapeutically to replace damaged retinal neurons.

Cell Culture Techniques↗