PubMed Health⌕ Search

Biomedical subjects

Hong Chen

Publications and source records attributed to Hong Chen.

At least 127 records · Page 7Linked to original sources
PubMed2005

Phosphorylated heat shock protein 27 is involved in enhanced heart tolerance to ischemia in short-term type 1 diabetic rats.

AIM: To examine the tolerance of type 1 diabetic hearts to ischemia and reperfusion injury. Myocardial contents of 27-kDa and 70-kDa heat shock proteins (hsp) as well as phosphorylated hsp27 were also determined. METHODS: Hearts from hyperglycemic rats 3 weeks after streptozocin injection and age-matched normal rats were subjected to ischemia and reperfusion in vitro. Cardiac function and electrocardiogram were recorded throughout experiments. Myocardial heat shock proteins were detected with Western blot. RESULTS: Despite depressed systolic function at the baseline, diabetic hearts exhibited considerable enhancement in post-ischemic heart function, manifested by an increase in the maximal rate of left ventricular pressure rise and fall (post-ischemic dp/dtmax and dp/dtmin were 560+/-117 and -313+/-68 mmHg/s in control, n=7, 1249+/-57 and -1204+/-36 mmHg/s in diabetes, n=10, P<0.01). Reperfusion ventricular fibrillation in the diabetic group were attenuated compared with controls (1.5+/-0.3 vs 7.2+/-2.1 min in control, P<0.01). The increased heart resistance to ischemia in diabetes was associated with hyperglycemia and accompanied by enhanced expression of myocardial phosphorylated hsp27 with normal aortic vessel relaxation. Cardioprotection was abrogated by metabolic correction with insulin and accompanied by phospho-hsp27 reduction. CONCLUSION: Heart resistance to ischemia is increased in type 1 diabetes, and hyperglycemia may present a mild yet stressful stimulus leading to upregulation of endogenous stress protein, which may play a potential role in cardioprotection and compensate for detrimental effects of hyperglycemia in diabetes.

Animals↗
PubMed2005

Surface properties of PEO-silicone composites: reducing protein adsorption.

Silicone-based polymers with reduced protein adsorption were successfully prepared by incorporating mono- or bifunctional poly(ethylene oxide) (PEO) derivatives, respectively, into PDMS during rubber formation using classic room temperature vulcanization chemistry. Characterization of the films by water contact-angle measurements and XPS showed that the PEO was present on the film surface, with greater amounts of PEO at the interface modified with monofunctional PEO. Scanning electron microscopy showed the PEO domains segregated into regular zigzag patterns on the PEO-modified surfaces. Significant reductions in the adsorption of fibrinogen, albumin and lysozyme were observed on both PEO-modified surfaces, although the monofunctional PEO surfaces performed much better in this regard. The reductions in protein adsorption were comparable for all three proteins on both surfaces, suggesting that molecular mass of the protein is not a significant factor in determining the magnitude of protein deposition. Western blot studies showed that the adsorption of proteins from plasma to the monofunctional PEO-modified surfaces was also significantly reduced and surprisingly selective, with very few bands noted relative to the control surfaces and those modified with bifunctional PEO.

Adsorption↗
PubMed2005

Synthesis and hybridization studies of DNA on functionalized polypropylene surfaces.

Polypropylene (PP) slice was treated with plasma in a mixture of nitrogen and hydrogen (1:2 V/V). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated the successful grafting of amino groups. The as-treated slices were successively applied to the in-situ synthesis of oligonucleotides and an average coupling yield of more than 98% was achieved. The hybridization signals were recorded with fluorescent analysis system. The complementary and mismatched sequences were distinguished clearly, and the ratio of fluorescence intensity values (arbitrary units) for perfect match:single base mismatch:two bases mismatch:three bases mismatch is 108.6: 62.9: 22.4: 5.5. The results implied the plasmamodified PP surface was extremely stable, performed well in DNA hybridization assays, and could service as a good substrate for high-density oligonucleotide array synthesis, especially in a multistep molecular stamping method to fabricate DNA microarrays in-situ on a large scale.

DNA Probes↗
PubMed2005

Pravastatin attenuates ceramide-induced cytotoxicity in mouse cerebral endothelial cells with HIF-1 activation and VEGF upregulation.

Ceramide is a pro-apoptotic lipid messenger that induces oxidative stress and may mediate apoptosis in cerebral endothelial cells (CECs) induced by TNF-alpha/cycloheximide, lipopolysaccharide, oxidized LDL, IL-1, and amyloid peptide. Exposure of CECs to C2 ceramide for 12 h caused cell death in a concentration-dependent manner, with a LC50 of 30 microM. Statins are inhibitors of 3-hydroxyl-3-methyl coenzyme A reductase which is the rate-limiting enzyme for cholesterol biosynthesis. Pretreatment with pravastatin at 20 microM for 16 h substantially attenuated ceramide cytotoxicity in mouse CECs. Increases in vascular endothelial growth factor (VEGF) expression were detected within 1-3 h after pravastatin treatment. This pravastatin action was accompanied by the activation of hypoxia-inducible factor-1 (HIF-1), a transcription factor known to activate VEGF expression. These results raise the possibility that pravastatin may protect CECs against ceramide-induced death via the HIF-VEGF cascade.

Animals↗
PubMed2005

The impact of threatening information about pain on coping and pain tolerance.

This study examined the impact of threatening information on coping and pain tolerance in a healthy adult sample. Prior to engaging in a Cold Pressor Test (CPT), 121 college students were randomly assigned to one of three conditions: a threat condition in which they read an orienting passage warning them about symptoms and consequences of frostbite (pain as a signal for nociception), a reassurance condition in which they read an orienting passage about the safety of the CPT (pain independent of nociception), or a control condition in which no orienting passage was read before the experimental task. Only 15.6% of participants in the threat group completed the CPT to its 4-minute duration, compared with 55.6% in the reassurance group and 45.2% of those in the control group. Even though groups did not differ on level of reported pain, threatened participants catastrophized more about the pain and reported less use of cognitive coping strategies (reinterpreting pain sensations, ignoring pain, diverting attention away from pain to other experiences, and using coping self-statements) than other respondents. A path analysis indicated that the relation between threat and pain tolerance was fully mediated by catastrophizing and cognitive coping. Together, findings suggest that pain appraised as threatening contributes to a specific pattern of coping responses associated with a reduced capacity to bear pain.

Adaptation, Psychological↗
PubMed2005

Bioremediation potential of spirulina: toxicity and biosorption studies of lead.

This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0-12 min) the adsorption rate was so rapid that 74% of the metal was biologically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 10(5) alga cells.

Bacterial Proteins↗
PubMed2005

The long-term results of gamma knife radiosurgery for hemangioblastomas of the brain.

OBJECT: The authors assessed the long-term result of gamma knife surgery (GKS) for hemangioblastomas of the brain (HABs) and show histopathological findings after GKS. METHODS: Thirty-five patients, 28 men and seven women, with a mean age of 36 years underwent GKS. Eighteen patients presented with multiple tumors and 17 with a solitary tumor. Twenty-one patients had von Hippel-Lindau (VHL) disease. The mean tumor diameter was 13 mm (range 5-55 mm). The mean follow up after GKS was 66 months (range 24-114 months). The mean prescription dose was 17.2 Gy (range 12-24 Gy) at the tumor margin. For tumors close to or within the brainstem a prescription dose of 12 to 13 Gy was used. At the most recent follow up, 29 patients were alive, six were dead, and satisfactory tumor control had been achieved in 29. A stable or improved neurological status was obtained in 21 patients. Eight patients underwent open surgery because of tumor-associated cyst enlargement or the development of new tumors after GKS. Seven patients developed new tumors and five of them required a second GKS. The 1-year tumor control rate was 94%; 2 years, 85%; 3 years, 82%; 4 years, 79%; and 5 years, 71%. Histopathology showed that no tumor cells were found and there was degeneration and necrosis in a tumor nodule 48 months after GKS with a prescription dose of 18 Gy. CONCLUSIONS: Gamma knife surgery was a useful choice for small- or medium-sized, solid HAB in the long term, especially when the tumor margin dose was 18 Gy. Although GKS can treat multiple tumors in a single session, for HABs associated with VHL disease, GKS faces the dual problems of tumor recurrence or development of a new tumor.

Adolescent↗
PubMed2005

[Expression of epidermal growth factor-adenovirus E4orf4 fusion protein in tumor cells and its cytotoxicity].

BACKGROUND & OBJECTIVE: Human epidermal growth factor (EGF), an important growth factor, may stimulate cell growth and proliferation. EGF receptor (EGFR) expresses on the surface of normal cells, and abnormally over-expresses on many kinds of tumor cells, especially on solid tumor cells. Adenovirus early region 4 open reading frame 4 protein (E4orf4) is a novel cytotoxin that can specifically induce p53-independent apoptosis in tumor cells. Based on the targeting of EGF and cytotoxicity of E4orf4, we proposed to design a novel fusion protein at molecular level by recombining EGF and E4orf4 to target and then kill tumor cells. METHODS: EGF and E4orf4 coding sequences were amplified by polymerase chain reaction (PCR), and then genetically fused by overlapping PCR. EGF-E4orf4 fragment was cloned into the yeast expression vector. Recombinant plasmid DNA was transformed into the yeast Pichia pastoris. Fusion proteins were purified by SP Sepharose ion exchange chromatography. Cytotoxicity of EGF-E4orf4 on cultured BT325 and MDA-MB-231 cells was detected by MTT assay, and cell apoptosis was measured by flow cytometry. RESULTS: The fusion fragment has 805 base pairs, which consists of Kozak consensus sequence, and the sequences encoding alpha-factor signal peptide, EGF, flexible linker, and E4orf4. Recombinant plasmids pAO-EGF-E4orf4, and pAO-3EGF-E4orf4 were obtained, the latter contained 3 expression cassettes. Apparent molecular weight of fusion protein was 20 ku. Immunoblot analysis showed that the fusion protein was immunoreactive with rabbit-anti-human EGF polyclonal antibody. EGF-E4orf4 in high concentrations (5, and 0.5 microg/ml) inhibited growth of BT325 and MDA-MB-231 tumor cells as compared with controls. Apoptosis was induced in 15.4%-28.2% of MDA-MB-231 cells by EGF-E4orf4 at the dosage of 10-25 microg/3 x 10(5) cells. CONCLUSIONS: Fusion protein EGF-E4orf4 may enter cells mediated by EGFR, and thus inhibit growth of tumor cells.

Adenovirus E4 Proteins↗
PubMed2005

[Comparison of esophageal acid exposure characteristics between reflux oesophagitis and non-erosive reflux diseases].

OBJECTIVES: Comparing the esophageal acid exposure characteristics between reflux oesophagitis (RE) and non-erosive reflux disease (NERD) patients to identify the NERD subgroups. METHODS: One hundred and twenty-eight patients with heartburn and acid regurgitation were evaluated. Esophageal mucosa injury was assessed by gastroscopy. The extent of esophageal acid exposure was determined by ambulatory 24 h esophageal pH monitoring. DeMeester point >/= 15 was taken as positive. RESULTS: Thirty-seven patients were found to have RE (28.9%), 91 were diagnosed as NERD. There was no difference at DeMeester point between RE and NERD (P > 0.05). Patients with RE have more long reflux episodes than NERD patients (8.16 +/- 10.27 vs 3.96 +/- 6.87; P = 0.004). Among NERD patients, 46 (50.5%) had an abnormal pH monitoring (NERD+); another 45 were normal (NERD-). Patients with NERD+ were more likely to demonstrate at positive symptom index (SI > 50%) than those with NERD- (43.5% vs 15.6%; P < 0.001). In NERD- group, patients with a positive SI (NERD-SI+) have more reflux episodes than those with a negative SI (NERD-SI-) (55.29 +/- 24.68 vs 34.87 +/- 24.06; P < 0.05), as well as the fraction time of 24 h that pH < 4 in upright (4.16 +/- 2.98 vs 1.88 +/- 1.60; P < 0.05). Twenty-five RE patients have an abnormal pH monitoring (RE+, 67.6%), another 12 were normal (RE-). RE- patients have a higher median of intra-esophageal and gastric pH than RE+ patients respectively (6.75 +/- 0.42 vs 5.18 +/- 1.32; 2.69 +/- 2.59 vs 1.49 +/- 0.66; P < 0.05). CONCLUSIONS: RE patients have longer reflux episodes than NERD. The symptoms of most gastroesophageal reflux disease patients associate with acid reflux. Acid reflux characteristics and symptom patterns suggest subgroups of NERD patients. The bile or mixed reflux may be involved in the pathogenesis of RE- group.

Adolescent↗
PubMed2005

[Effects of withdrawal of statins on nitric oxide production in vascular endothelial cells].

OBJECTIVE: To investigate the effects of withdrawal of statins on endothelial nitric oxide production in human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were treated with simvastatin or lovastatin (10(-6) mmol/L) for 24 hours, then the drugs were replaced by a medium. At 6, 12, 18 and 24 hours after stopping statin treatment, nitric oxide production was measured with Griess reagents. Levels of endothelial nitric oxide synthase (eNOS) mRNA were examined with reverse transcription polymerase chain reaction (RT-PCR). RESULTS: After 24 hours of incubation, both simvastatin and lovastatin increased the nitric oxide production by (173 +/- 33)% and (170 +/- 44)% respectively and the production of nitric oxide at 24 hours after withdrawal of statins decreased by (64 +/- 9)% and (49 +/- 10)% respectively. These effects of simvastatin and lovastatin on eNOS mRNA expression correlated with changes in nitric oxide production. CONCLUSIONS: Withdrawal of statins can decrease the production of nitric oxide and the expression of eNOS mRNA, which may account for high cardiovascular events rate in clinical study when statins treatment was stopped abruptly.

Cells, Cultured↗
PubMed2005

[Comparison of the effects of general and epidural anesthesia for cesarean section on fetuses].

OBJECTIVE: To determine the safety of regular doses of general anesthesia and epidural anesthesia on neonates delivered by cesarean sections. METHODS: Singleton pregnant women for whom elective cesarean sections were planned after 37 gestational weeks were allocated to general anesthesia group (platelet count < 50 x 10(9)/L) or epidural anesthesia group (platelet count > or = 50 x 10(9)/L). Arterial and venous samples were withdrawn from the doubly clamped umbilical cord segment at delivery for the pH, bicarbonate, PO2, and PCO2. All delivery times, birth weights, and Apgar scores at 1 min, 5 min were recorded. RESULTS: The mean Apgar score at 1 min for the general anesthesia group was 9.5 +/- 1.1 and 9.8 +/- 0.7 for the epidural anesthesia group, without significant difference (P > 0.05). The Apgar scores at 5 min of all newborns were 10. The mean umbilical arterial and venous blood pH for the general anesthesia group were 7.31 +/- 0.06, 7.31 +/- 0.04, and 7.28 +/- 0.07, 7.32 +/- 0.05 for the epidural anesthesia group respectively. No significant difference was found between the two groups (P > 0.05). CONCLUSIONS: Our prospective study suggests that mode of anesthesia does not influence significantly the outcome of newborn infants delivered by elective cesarean section. It seems that both general and epidural anesthesia can be used in elective term cesarean sections safely.

Adult↗
PubMed2005

[Efficacy and safety of combination therapy with simvastatin and fenofibrate for combined hyperlipidemia].

OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of combination therapy with simvastatin and fenofibrate in patients with combined hyperlipidemia. METHODS: A total of 221 patients with combined hyperlipidemia were randomly assigned to receive 10 mg simvastatin (n = 72) or 200 mg fenofibrate (n = 68), or a combination of 10 mg simvastatin + 200 mg fenofibrate (n = 81) for 6 months. Lipid profiles, physical and laboratory investigations for adverse effects were assessed. RESULTS: (1) Combination treatment were more effective in normalizing lipid profile than any monotherapy. Serum TC, LDL-C, and TG were reduced by 30%, 37% and 56% respectively, whilst HDL-C significantly increased by 24% (all P < 0.01). The improvement in TG and HDL-C achieved by combination treatment was superior to fenofibrate or simvastatin alone. (2) The success rate of TC, LDL-C and TG control in the combination therapy group were 51%, 55% and 61% respectively, with an overall success rate (all three together) of 45%, which was superior to either drug given as monotherapy. (3) All treatments were well tolerated with no increase in adverse events for combination therapy versus monotherapy. CONCLUSION: The results of this study demonstrated that combination therapy with fenofibrate (200 mg/day) and low-dose simvastatin (10 mg/day) is more effective than monotherapy in patients with combined hyperlipidemia, and is generally safe and well tolerated.

Drug Therapy, Combination↗
PubMed2005

[Prevalence for isolated systolic hypertension and analysis on its relative factors in 1002 cases >or= 80 year old persons].

OBJECTIVE: To study and analysis prevalence and incidence of target organ injury and the relative factors for isolated systolic hypertension (ISH) in Beijing. METHODS: 1002 cases aged 80 to 99 years were investigated in 28 cadre retirement centers in Beijing. Blood pressure was taken for three times with mercurial sphygmomanometer in every person, the mean values were recorded and the relative material was gathered according to questionnaire after the health education. Physical examination form of outpatient department and inpatient case history in fixed hospital were analyzed. RESULTS: In 1002 very old persons, there were 673 hypertensive patients (67.2%) and 455 ISH (45.4%). Among all hypertensive patients, the rate of ISH was 67.6% and double hypertension was 32.4%. Awareness rate was 87.90% and 97.71%, taking antihypertensive drug rate was 77.58% and 80.73%, control rate was 58.68% and 62.84% in ISH and in double hypertension group, respectively, which were no significant differences between the two groups. There was no significant difference in morbidities of cardiac heart disease, myocardial infarction and chronic renal insufficiency between the two groups. The incidences of heart failure, cerebrovascular disease, disability and dementia were 4.62% and 8.72%, 41.54% and 55.50%, 10.55% and 16.06%, 8.57% and 12.84% in ISH and double hypertension group, respectively, which were significant differences between the two groups (P < 0.01). The susceptible age period for ISH was 70 to 79 years in this study. CONCLUSION: ISH is more common in hypertensive patients in very old persons at 28 cadre retirement centers in Beijing. Morbidity of heart failure, cerebrovascular disease, disability and dementia were higher in double hypertension group compared with those in ISH group. The results showed that increase of both systolic and diastolic blood pressure was more dangerous than that of systolic pressure only for very old persons. The improvement of small arterial plastic and the control of blood pressure to target level (< 140/90 mm Hg) in very old hypertensive patients are very important for decreasing the incidence of target organ injury and increasing their life quality and late survival rate.

Aged, 80 and over↗
PubMed2005

[Experimental research of the expression of telomerase in corneal limbal epithelial cells].

OBJECTIVE: To explore the possibility of using telomerase as a marker of corneal limbal stem cells. METHODS: Corneal limbal tissues and central corneal epithelial tissues from 8 rabbits were examined for telomerase activity qualitatively by telomere repeat amplification protocol (TRAP) and quantitatively by detecting the light value with bioluminescent technique. 5-Fu (20 mg) was injected subconjunctivally in 4 rabbits and the other 4 rabbits were not injected. RESULTS: Telomerase activity was positive in all corneal limbal tissues and negative in all central corneal tissues. Telomerase activity of corneal limbal cells (light value 165,575) was significantly higher than that of central corneal epithelial cells (light value 34,912) by bioluminescent technique (P = 0.001). 5-Fu injection group showed higher telomerase activity than that of the group without injection (light value 145,754) (P = 0.02). CONCLUSIONS: Positive telomerase activity is detected in the corneal limbal tissues. It suggests that there are cells with high proliferative ability in the corneal limbus. Telomerase activity may be used as a marker of corneal limbal stem cells.

Animals↗
PubMed2005

[Polymorphism Analysis of the CSN1S2 Gene Digested.].

PCR-RFLP was applied to analyze the polymorphism of CSN1S2 gene in 170 goats that comprised of five goat breeds, namely Xinong Saanen dairy goat, Guanzhong dairy goat, Shaannan white goat, Angora goat and Boer goat. A 310 bp -long PCR product was digested with Alw26I and demonstrated polymorphism in five goat populations that were all at Hardy-Weinberg equilibrium (P>0.05). For Xinong Saanen dairy goat, Guanzhong dairy goat, Shaannan white goat, Angora goat and Boer goat, gene heterozygosity/effective allele gene number/Shaanon information entropy /Polymorphism information content were 0.1589/1.1889/0.2955/0.1463, 0.4114/1.6981/0.6017/0.5171, 0.1653/1.1980/0.3046/0.1516, 0646/1.0691/0.1463/ 0.0625, 0.0541/1.0572/0.1270/ 0.0526, respectively. According to the heredity diversity indexes described above of the five goat breeds, Guanzhong dairy goat had the most abundant heredity diversity and showed high polymorphism, and Xinong Saanen dairy goat and Shaannan white goat were inferior, while Angora goat and Boer goat had the lowest genetic variability.

Alleles↗
PubMed2005

[Relationship between polymorphism of growth hormone gene and production traits in goats].

Growth hormone (GH) plays an important role in animal growth and development, and the growth hormone gene can be considered as a candidate gene for studying the weight in goats. The function of GH gene has been intensively studied in cattle and pigs, while in goats the study is still rare. In this paper 224 goats including LuBei White goat, Boer goat, hybrid generation 1 and backcross generation 1 of Boer goat and LuBei White goat were used. Two pairs of primers for 5' region of GH gene were designed according to the database of goat genomic sequence (Accession No. D00476) and polymorphisms were detected by PCR-SSCP. Homozygotes of the polymorphic fragment were cloned and sequenced. The result showed that there were five substitution mutations in the two fragments. Statistical analysis showed that in the fragment amplified by the first pair of primers, AA genotype had significant higher birth weight and weight of one year old than BB and AB genotypes in Boer goats (P<0.05). In hybrid generation 1 AA genotype also had higher birth weight and weight of one year old in significantly. While in LuBei White goats BB genotype had lower weight and the weaning weight was significant lower than the other two genotypes (P<0.05). In the fragment amplified by the second pair of primers there was no significant difference among different genotypes. From these results we can preliminarily draw the conclusion that GH gene may be a major gene or linked to the major gene to affect the weight traits and the polymorphic site could be used to select the goat weight in marker-assisted selection program.

5' Flanking Region↗
PubMed2005

[Study on mitochondrial DNA D-loop polymorphism in Chinese donkeys].

The mitochondrial DNA (mtDNA) D-loop sequences with 399 bp in 26 individuals from 5 donkey breeds in China were analyzed. Aligned by Clustal W software,the results showed that 23 polymorphic nucleotide sites and only transition with the percentage of 5.76% in 399 bp were observed. In reference to mtDNA D-loop sequences of European domestic donkey as a control, the average percentage of mtDNA D-loop nucleotide variation in 5 Chinese donkey breeds was 1.80%. The average percentages of D-loop nucleotide variation from Liangzhou donkey (LZ), Yunnan donkey (YN), Guanzhong donkey (GZ), Xinjiang donkey (XJ) and Jiami donkey (JM) were 0. 35%, 1.25%, 2.30%, 2.91% and 2.20% respectively. The average sequence divergence estimated from D-loop sequences varied from 0.25% - 5.01% within breeds and 4.51% - 5.51% among breeds, respectively, demonstrating that there existed rather abundant mitochondrial genetic diversity in Chinese donkeys. Comparisons of the 26 sequences revealed 11 mitochondrial haplotypes; the percentage of haplotype was 42.31%. This phenomenon demonstrated that the mitochondrial genetic diversity in Chinese donkey breeds is being reduced. It is urgent to protect the genetic resources of Chinese donkey. The molecular phylogenetic tree of mtDNA D-loop sequences in 5 Chinese donkey breeds,6 sequences of Asian wild ass (Equus asinus kiang, Equus asinus kulan, Equus asinus hemionus;) and 4 sequences of European domestic donkeys from GenBank was constructed by Neighbor-Joining method. It was the first time proved in molecular level that the origin of Chinese donkey breeds was from African wild ass (Equus africanus africanus and Equus africanus somaliensis), not from Asian wild ass as bescribed in the paper.

Animals↗