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Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 37 records · Page 2Linked to original sources
PubMed2005

A study of neonatal swimming (water therapy) applied in clinical obstetrics.

OBJECTIVE: To study the significance of some clinical parameters related to neonatal 'swimming' (water therapy) during hospitalization. METHODS: Normal newborns were randomly divided into two groups to observe their birth weight, weight before discharge,time of first defecation and meconium turning yellow. Group one was the swimming (study) group, comprising a total of 223 newborns including 127 babies delivered after spontaneous vaginal delivery and 96 babies after Cesarean section. Group two was the bathing (control) group, comprising 154 newborns including 109 babies delivered after spontaneous vaginal delivery and 45 babies after Cesarean section. RESULTS: There was no significant difference in birth weight between the two groups (p > 0.05). However, the mean weight before discharge of the babies in the study group was 3.29 + 0.35 and 3.51 + 0.40 kg, spontaneous vaginal delivery vs. Cesarean section, compared with 3.09 + 0.38 and 3.17 + 0.48 kg, respectively, in the control group (p < 0.01). The corresponding mean times of meconium turning yellow were 39.15 + 15.88 and 39.02 + 13.60 h in the study group compared with 48.01 + 19.42 and 55.67 + 25.05 h in the control group. This difference was significant (p < 0.01), as was the difference between the time of first defecation (p < 0.05). CONCLUSION: Neonatal swimming can accelerate babies' growth in the early stage.

Baths↗
PubMed2005

The effect of mizolastine on expression of vascular endothelial cell growth factor, tumour necrosis factor-alpha and keratinocyte-derived chemokine in murine mast cells, compared with dexamethasone and loratadine.

It has been shown that many antihistamines may have anti-inflammatory activity in addition to being H1 antagonists. Mizolastine (MIZ), a novel antihistamine, might also have anti-angiogenesis properties. In this study, we investigated the influence of MIZ on proangiogenesis factors, vascular endothelial cell growth factor (VEGF), tumour necrosis factor (TNF)-alpha and keratinocyte-derived chemokine (KC) in murine mast cells by using ELISA and RT-PCR, as compared with dexamethasone (DEX) and loratadine (LOR). Our results show that MIZ is effective in the inhibition of KC, VEGF and TNF-alpha release induced by an IgE-dependent mechanism, in a time- and dose-dependent manner. The differences between the inhibitory effects of the three drugs on these proangiogenic factors were rather subtle. Semiquantitative analysis using RT-PCR showed that the three drugs significantly reduced VEGF165, VEGF120, TNF-alpha and KC mRNA expression. Statistical results revealed that the effect of DEX on VEGF165 mRNA was different from that of MIZ or LOR (P < 0.01) and the differences between the three drugs on VEGF120, TNF-alpha and KC mRNA were not statistically significant (P > 0.05). These findings raise the possibility that MIZ can mediate anti-angiogenesis activity and that the effect may depend not only on the inhibition on the levels of cytokine proteins but also at the mRNA level.

Angiogenesis Inducing Agents↗
PubMed2005

The expression of the HSP90 gene in response to winter and summer diapauses and thermal-stress in the onion maggot, Delia antiqua.

The full-length Hsp90 cDNA in Delia antiqua was cloned and sequenced. The deduced polypeptide comprised 717 amino acid residues, with a molecular mass of 82 140 Da. Summer- and winter-diapauses both elevated HSP90 transcript levels in D. antiqua pupae. Levels gradually increased with time in summer diapausing pupae whereas levels fluctuated in winter diapausing pupae. Cold- and heat-stressing summer- and winter-diapausing individuals further elevated HSP90 expression. mRNA levels gradually increased with time in summer diapausing pupae whereas levels decreased with time after an initial increase in winter diapausing pupae. HSP90 expression was also up-regulated following cold- and heat-stresses in non-diapausing pupae. Heat-stress gradually increased the mRNA level with time whereas cold-stress gradually decreased levels after an initial increase. These results suggest that the development and physiology of summer- and winter-diapauses, as monitored via variation in HSP90 transcript levels, can be substantial different.

Animals↗
PubMed2005

Expression of tumour necrosis factor receptors by bronchoalveolar cells in hypersensitivity pneumonitis.

Tumour necrosis factor receptors (TNFR) and the Fas receptor (FasR) have been implicated in the pathogenesis of interstitial lung diseases. The current authors examined the expression of TNFR-1, TNFR-2 and FasR by bronchoalveolar cells in hypersensitivity pneumonitis (HP). Cell surface receptor expression on bronchoalveolar lavage cells was analysed by immunocytochemistry in 11 HP patients, 11 idiopathic pulmonary fibrosis (IPF) patients and 10 controls. TNFR-1, TNFR-2 and FasR were expressed on a higher percentage of alveolar macrophages (AM) in HP compared with controls and IPF patients. TNFR-2 and FasR expression on lymphocytes was also higher in HP than in controls and in IPF. TNFR-1, TNFR-2 and FasR expression correlated positively with the percentage of lymphocytes, and negatively with the percentage of AM in HP. Expression of TNFR-1 on AM and TNFR-2 on lymphocytes correlated with the percentage of neutrophils in HP. In conclusion, this study shows evidence of altered expression of tumour necrosis factor superfamily receptors in hypersensitivity pneumonitis.

Aged↗
PubMed2005

Association of polymorphisms and haplotypes in the human growth hormone 1 (GH1) gene with breast cancer.

The growth hormone 1 (GH1)/insulin-like growth factor I (IGF-I) axis plays an important role in the development of breast cancer. By binding to its receptor, GH1 stimulates the production of IGF-I and its binding protein IGFBP3, resulting in the regulation of cell proliferation, differentiation and apoptosis. The GH1 gene expression is regulated by a highly polymorphic proximal promoter and a distal locus control region (LCR) 14.5 kb upstream of the gene. We investigated the effect of single nucleotide polymorphisms (SNPs) in the LCR and in the promoter region and an intron 4 SNP (IVS4+90 T/A) on breast cancer risk in a large cohort of Polish and German familial breast cancer cases and controls. SNPs in the LCR did not show an influence on breast cancer risk, either alone or in haplotypes. Three SNPs in the promoter region (G-340T, A-68G/C and A-63T/C) showed an increased and four SNPs (A-137G, G-119T, G-93delG and T-4G) a decreased allele frequency in the cases compared with the controls. Two of the SNPs (A-137G and G-93delG) lead to a decreased breast cancer risk among the minor allele carriers in the joint analysis of the two populations (odds ratio (OR) 0.62, 95% confidence interval (95% CI) 0.44-0.89, P = 0.01 and OR 0.65, 95% CI 0.47-0.90, P = 0.01, respectively). Haplotype analysis with these seven promoter SNPs revealed a protective association (OR 0.61, 95% CI 0.37-1.00, P = 0.04) for the haplotype GAGdAAT, containing the G-93delG variant allele, which in the single analysis already showed a protective effect. The effect was marginally stronger in combination with the LCR GC haplotype (OR 0.49, 95% CI 0.23-1.01, P = 0.04).

Adult↗
PubMed2004

Piezoelectric sensors for dioxins: a biomimetic approach.

The aim of this work was to design a fast, cheap and easy to use analytical system for dioxins. Piezoelectric sensors coupled with the pentapeptides as biomimetic traps (the receptors), selective for the dioxins, were used for the realisation of this analytical system. A methodology to select specific receptors among all possible pentapeptides randomly generated was represented by the use of molecular modelling software. Three peptides called later on A, B and C (A:[N]Asn-Phe-Gln-Gly-Ile[C]; B:[N]Asn-Phe-Gln-Gly-Gln[C]; C:[N]Asn-Phe-Gln-Gly-Phe[C]), were selected and evaluated for their potential usage as artificial receptors in solid-gas analysis by using a quartz crystal microbalance (QCM) sensors array. The peptide sequences were functionalised by two terminal cysteine residues in order to achieve a covalent interaction with the QCM gold surface. A manganese-porphyrin complex and two other pentapeptides, a pentaglutamine (pentapeptide D) and a pentalysine (pentapeptide E), were used as negative control sensors. The QCM sensors (A, B and C) gave a good linearity against different sample concentrations of the 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) and a mixture of dioxins. In particular, the selectivity against 2,3,7,8-TCDD was nicely correlated to the estimated binding energy of the receptors calculated by computational modelling. The cross-reactivity of the system was quantified using commercial polychlorinated biphenyls (PCBs) mixtures (dioxin-like compounds).

Biomimetics↗
PubMed2004

Photochemical degradation of 1,3-dinitrobenzene in aqueous solution in the presence of hydrogen peroxide.

A study on the destruction of 1,3-dinitrobenzene (1,3-DNB) in aqueous solution was carried out under ultraviolet (UV) irradiation alone and UV irradiation in the presence of hydrogen peroxide (H2O2). The combination of UV and H2O2 is significantly effective in degrading 1,3-DNB in terms of initial reaction rate and the mineralization of organic carbons. The photodegradation process can be influenced in certain extent by increasing the content of H2O2 and the acidity of reaction matrices. It was found that a variety of phenolic intermediates and inorganic acid were formed via hydroxyl radicals attacking the parent compound. The UV/H2O2 oxidation of 1,3-DNB was characterized by pseudo-zero order reaction for the degradation of 1,3-DNB with a 20 times enhanced rate constant of 1.36 x 10(-7) Ms(-1) and the initial rate constant was dependent on the initial concentration of 1,3-DNB.

Chromatography, High Pressure Liquid↗
PubMed2004

EDAG regulates the proliferation and differentiation of hematopoietic cells and resists cell apoptosis through the activation of nuclear factor-kappa B.

Erythroid differentiation-associated gene (EDAG) is considered to be a human hematopoiesis-specific gene. Here, we reported that downregulation of EDAG protein in K562 cells resulted in inhibition of growth and colony formation, and enhancement of sensitivity to erythroid differentiation induced by hemin. Overexpression of EDAG in HL-60 cells significantly blocked the expression of the monocyte/macrophage differentiation marker CD11b after pentahydroxytiglia myristate acetate induction. Moreover, overexpression of EDAG in pro-B Ba/F3 cells prolonged survival and increased the expression of c-Myc, Bcl-2 and Bcl-xL in the absence of interleukin-3 (IL-3). Furthermore, we showed that EDAG enhanced the transcriptional activity of nuclear factor-kappa B (NF-kappa B), and high DNA-binding activity of NF-kappa B was sustained in Ba/F3 EDAG cells after IL-3 was withdrawn. Inhibition of NF-kappa B activity resulted in promoting Ba/F3 EDAG cells death. These results suggest that EDAG regulates the proliferation and differentiation of hematopoietic cells and resists cell apoptosis through the activation of NF-kappa B.

Apoptosis↗
PubMed2004

Genetic variation and population structure of the mosquito Anopheles jeyporiensis in southern China.

Genetic differentiation among populations of Anopheles jeyporiensis was examined using 76 mtDNA COII sequences from 16 sites throughout southern China and northern Vietnam. The COII sequences are AT-rich (74.58%) and reveal high levels of diversity with 39 of 685 sites polymorphic and 50 different haplotypes present. Genetic variation is high within populations and significant geographical structure was detected at both population and regional levels. In the larger samples, the distributions of haplotypes suggest recent population expansion.

Analysis of Variance↗
PubMed2003

MIP-based solid phase extraction cartridges combined with MIP-based sensors for the detection of microcystin-LR.

Microsystin-LR is one of the most widespread and dangerous toxins produced by the freshwater Cyanobacteria. The contamination of water supplies with microcystin-LR has been reported in several areas around the world and the development of an easy-to-use, rapid, robust and inexpensive sensor for this toxin is urgently required. In this work an artificial receptor for microcystin-LR was synthesised using the technique of molecular imprinting. The composition of the molecularly imprinted polymer (MIP) was optimised using computer modelling. The synthesised polymer was used both as a material for solid-phase extraction (SPE) and as a sensing element in a piezoelectric sensor. Using the combination of SPE followed by detection with a piezoelectric sensor the minimum detectable amount of toxin was 0.35 nM. The use of MIP-SPE provided up to 1000 fold pre-concentration, which was more than sufficient for achieving the required detection limit for microcystin-LR in drinking water (1 nM). This work is the first example where the same MIP receptor has been used successfully for both SPE and the corresponding sensor.

Adsorption↗
PubMed2003

Major form of NUP98/HOXC11 fusion in adult AML with t(11;12)(p15;q13) translocation exhibits aberrant trans-regulatory activity.

Three adult patients with de novo acute myeloid leukemia of distinct subtypes harboring t(11;12)(p15;q13) have been investigated to characterize the genes involved in that translocation. Through molecular cytogenetics, a chromosome break was detected at the 3' part of nucleoporin 98 (NUP98) gene at 11p15. Using rapid amplification of cDNA end, we identified the partner gene at 12q13, HOXC11. Molecular analysis showed that exon 12 of NUP98 was fused in-frame to exon 2 of HOXC11 in all three cases with t(11;12)(p15;q13). Therefore, this type of fusion may represent the major form of the NUP98-HOXC11 chimera so far reported. Moreover, two out of three cases had a confirmed deletion of the 3' part of NUP98 gene and more telomeric region of 11p harboring a group of tumor-suppressor genes. Interestingly, the NUP98-HOXC11 protein when assayed in a GAL4 reporter system, showed an aberrant trans-regulatory activity as compared to the wild-type HOXC11 in both COS-7 and HL-60 cells. Therefore, NUP98-HOXC11 may contribute to the leukemogenesis by interfering with the cellular mechanism of transcriptional regulation.

Adult↗
PubMed2003

Analysis of factors influencing the blood levels and activities of tissue-type plasminogen activator (t-PA).

This study aimed to correlate plasmatic tissue-type plasminogen activator (t-PA) levels and activity with parameters of artery blood flow and vessel walls, nail fold microcirculation, hemorheology, serum glucose, and lipids. Thirty healthy volunteers (female/male 12/18) aged 40-60 (average 46) were included in the study. In citrate venous blood, the following parameters were determined: carotid mean velocity, carotid intimal-medial-thickness (IMT), capillary circulation parameters, hemorheology index, serum glucose, and lipids. Analysis of data showed that t-PA concentration was positively and significantly correlated with total cholesterol, triglycerides, and serum glucose (P<0.05, P<0.05, and P<0.01), but t-PA activity showed no correlation with them; among the hemorheology factors investigated, t-PA concentration showed the strongest positive correlation with both whole blood viscosity and reduced blood viscosity at high and low shear rate separately (P<0.01), t-PA activity showed no correlation with any hemorheology factors; t-PA concentration showed no correlation with any investigated nail fold capillary parameters, whereas t-PA activity was significantly and negatively associated with capillary loop number (P<0.05); t-PA concentration and activity was not associated with values of carotid maximum intimal-medial-thickness (mIMT) and mean velocity or systolic, diastolic blood pressure (P>0.05). But subjects with mIMT 1.0 mm showed higher t-PA levels compared with those with mIMT < 1.0 mm (P<0.05) and decreased carotid mean velocity (P<0.01). These findings suggest that multiple vascular disease risk factors would influence the t-PA level; t-PA concentration does not parallelize with t-PA activity.

Adult↗
PubMed2002

Regulation of estrogen target genes and growth by selective estrogen-receptor modulators in endometrial cancer cells.

OBJECTIVE: Tamoxifen has mixed agonist/antagonist activities, leading to tissue-specific estrogen-like actions and endometrial cancer. The purpose of this study was to evaluate the effects of antiestrogens on the growth of estrogen receptor (ER)-positive ECC-1 endometrial cancer cells in vitro and in vivo. METHODS: We performed growth studies and luciferase assays using ERE-tK and AP-1 reporters. ERalpha protein expression was measured by Western blot after antiestrogen treatments. We investigated the actions of antiestrogens on the transcription of the pS2 gene in situ measured by Northern blot and the actions of antiestrogens on the VEGF protein secreted by ELISA. ERalpha, ERbeta, EGFR, and HER2/neu mRNAs were determined by RT-PCR. Last, ECC-1 tumors were developed by inoculation of cells into ovariectomized athymic mice and treated with estradiol (E2), tamoxifen, raloxifene, and a combination. RESULTS: E2 induced cell proliferation while antiestrogens did not. E2 and raloxifene down regulated ERalpha protein; in contrast, 4OHT did not. ICI182,780 completely degraded the receptor. ECC-1 cells express ERbeta at insignificant levels. Luciferase assays did not show any induction in ERE- nor AP-1-mediated transcription by antiestrogens. E2 caused a concentration-dependent increase in pS2 mRNA but antiestrogens did not. E2 increased VEGF expression in a dose-dependent manner and antiestrogens blocked E2 action. E2 down regulated HER2/neu while 4OHT and raloxifene did not change HER2/neu levels compared to control. In addition, EGFR mRNA was down regulated by E2 but raloxifene did not change it. Tamoxifen and raloxifene did not promote tumor growth in vivo. However, raloxifene (1.5 mg daily) only partially blocked E2-stimulated growth. CONCLUSION: Tamoxifen and raloxifene are antiproliferative agents and antiestrogens in ECC-1 endometrial cells in vitro and in vivo. The observation that selective estrogen-receptor modulators do not down regulate EGFR and HER2/neu mRNA may provide a potential role for these oncogenes in the development of raloxifene- or tamoxifen-stimulated endometrial cancer. The ECC-1 cell line could provide important new clues about the evolution of drug resistance to tamoxifen and raloxifene.

Adenocarcinoma↗
PubMed2002

Research on the microstructure of insect cuticle and the strength of a biomimetic preformed hole composite.

The insect cuticle is a typical natural composite with excellent strength, stiffness, and fracture toughness. Scanning electron microscope observation of the microstructure of Hydrophilidae (an insect) cuticle showed several unique plies and structural characteristics, which may provide available information to the design of advanced composites. The microstructure found in the vicinity of pore canals in the insect cuticle was used for the design of the composite laminate with a hole. Compared with the composite laminate with a normally drilled hole, it was found that the strength of the specially designed composite laminate increases markedly, which is of important significance to the design of high-performance composites.

Animals↗
PubMed2002

Molecular and morphological studies on the Anopheles minimus group of mosquitoes in southern China: taxonomic review, distribution and malaria vector status.

Mosquitoes of the Anopheles minimus group (Diptera: Culicidae) from nine Provinces of southern China were identified morphologically and by molecular characterization, using single-strand conformation polymorphisms (SSCPs) and sequence data for the D3 region of the 28S ribosomal DNA and the mitochondrial COII locus. Species A and C (sensu Green et al., 1990) of the An. minimus complex were found to be sympatric in Yunnan Province. Species A occurs eastward from Yunnan through southern Guangxi, Hainan, Guangdong and Taiwan Provinces, whereas species C occurs northward to northern Guangxi, Guizhou and Sichuan Provinces. Morphological and molecular evidence (based on specimens from the field and four isofemale lines) shows that An. minimus forms A and B (sensu Yu & Li, 1984) are morphological variants of species A, which is accepted as An. minimus Theobald sensu stricto (type-locality: Pokfulam, Hong Kong). The so-called subspecies x of An. minimus (sensu Baba, 1950) is reinterpreted as An. aconitus Dönitz. The distribution and vector status of members of the An. minimus group are discussed in relation to the historical and current transmission of malaria and filariasis in China. Both An. minimus A and C have been implicated as widespread vectors of malaria, whereas only species A has been found in Hainan, where An. minimus s.l. was a vector of Bancroftian filariasis. The presence of An. aconitus in Hainan and Yunnan Provinces is confirmed, but the occurrence of An. varuna Iyengar and An. fluviatilis James, which were previously recorded in China, could not be verified.

Animals↗
PubMed2002

Idiopathic slow transit constipation and megacolon are not associated with neurturin mutations.

Chronic idiopathic slow-transit constipation (ISTC) and idiopathic megacolon (IMC) are early-onset gastrointestinal motility disorders of unknown aetiology. The gene encoding the neurotrophic factor neurturin may be a candidate for these disorders, as neurturin-deficient mice have a similar enteric phenotype. In the present study, we tested this hypothesis. Genomic DNA from 26 cases of chronic idiopathic STC [with a family history of constipation in 15 (58%) and Hirschsprung's disease in two (8%)], and five cases of IMC [two familial (40%)] was screened by direct DNA sequencing using the fluorescent dideoxy terminator method. Results were compared with published sequence data and 24 control DNAs. Our results revealed several previously unreported common sequence polymorphisms, but overall frequencies were comparable between patients and controls. We conclude that mutation of neurturin is not a frequent cause of ISTC or IMC.

Adult↗
PubMed2002

Relationships of local inhibitory and excitatory circuits to orientation preference maps in ferret visual cortex.

The contribution and precise role of intracortical circuits in generating orientation tuned responses in visual cortical neurons is still controversial. To address this question, the relationship between excitatory and inhibitory synaptic connections and orientation maps in ferret striate cortex was investigated by combining in vivo optical imaging and in vitro scanning laser photostimulation. Excitatory and inhibitory inputs to pyramidal cells originated preferentially from regions with similar orientation preference. Prominent cross-orientation inhibition was not observed, arguing against cross-orientation models of orientation selectivity. The tuning of inhibitory inputs was significantly broader in both layer 2/3 and layer 5/6 pyramidal neurons compared to the tuning of excitatory inputs. Local excitatory inputs were more prominent in the 0-20 degrees tuning difference range between pre- and postsynaptic cells than inhibitory inputs, whereas inhibition dominated in the 20-40 degrees tuning difference range. These differences in tuning of excitatory and inhibitory inputs onto individual cells are consistent with the predictions of recurrent models of orientation selectivity.

Animals↗