PubMed Health⌕ Search

Biomedical subjects

Chao Chen

Publications and source records attributed to Chao Chen.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Treatment for thyroid papillary cancer after nonstandard operation].

OBJECTIVE: To evaluate the disadvantage of nonstandard operation for thyroid papillary cancer, and the value of re-operation. METHODS: Eight hundred and ninety three thyroid papillary cancer patients (332 patients who received nonstandard operation received re-operation and 561 patients who received first standard operation in Zhejiang Cancer Hospital from January 1990 to January 2000) were retrospectively reviewed. RESULTS: Pathological results confirmed that there were 53.9% cases with residual cancer in re-operative specimen. The parathyroid was preserved in 74.1% cases in re-operation and 93.0% cases in standard operation (P < 0.01). The recurrent laryngeal nerve was injured in 3.3% cases in reoperation and 1.2% cases in standard operation (P < 0.05). The positive neck lymph node was 39.2% and 37.4% (P > 0.05), the 5-year local recurrence rate was 7.5% and 3.7% (P < 0.01), the total 5-year and 10-year cum-survival rates were 90.2%, 84.4% in patients with re-operation and 94.0%, 92.5% in patients with standard operation. The 10-year cum-survival rate were 67. 8% in patients with recurrence and 92. 9% in patients with non-recurrence in primary site respectively. Statistical analysis showed that the cancer recurrence influences the survival rate significantly (P < 0.01). CONCLUSIONS: In consideration of the higher residual tumor rate in patients who received nonstandard operations, the re-operations were necessary. But the re-operation could also leads to higher recurrence rate and more functional injuries. The standardized primary operation should therefore be formulated and advocated.

Adolescent↗
PubMed2006

Waste water disinfection during SARS epidemic for microbiological and toxicological control.

OBJECTIVE: To evaluate the disinfection of wastewater in China. METHODS: During the SARS epidemic occurred in Beijing, a study of different disinfection methods used in the main local wastewater plants including means of chlorine, chlorine dioxide, ozone, and ultraviolet was carried out in our laboratory. The residual coliform, bacteria and trihalomethanes, haloacetic acids were determined after disinfection. RESULTS: Chlorine had fairly better efficiency on microorganism inactivation than chlorine dioxide with the same dosage. Formation of THMs and HAAs does not exceed the drinking water standard. UV irradiation had good efficiency on microorganism inactivation and good future of application in China. Organic material and ammonia nitrogen was found to be significant on inactivation and DBPs formation. CONCLUSION: Chlorine disinfection seems to be the best available technology for coliform and bacteria inactivation. And it is of fairly low toxicological hazard due to the transformation of monochloramine.

Acetates↗
PubMed2006

[DBPs formation characteristics in chlorinating and relationship with chemical structure of some aromatic organic matter].

Some organic matter that have aromatic structure similar as humic acid are selected to conduct chlorination test, determined the formation of HAAs and THMs of tested matters, researched the relationship of the chemical structure of DBPFP with DBPs formation characteristics. The results indicated that: (1) The sequence of HAAs formation activity is p-Hydroxybenzoic acid > p-Aminoacetophenone > o-Benzenediol > m-Benzenediol; and THMs' s is m-Benzenediol > p-Aminoacetophenone > 2-Hydroxy-p-aminoacetophenone > p-Hydroxybenzoic acid. (2) The sequence of earlier chlorination reaction rate of HAAs is m-Benzenediol > p-Aminoacetophenone > p-Hydroxybenzoic acid > o-Benzenediol; and THMs' s is p-Hydroxybenzoic acid > 2-Hydroxy-p-aminoacetophenone > m-Benzenediol > p-Aminoacetophenone. (3) The substances that having the substituent group structure of para and ortho position are mostly format HAAs, and one's of having meta position are mostly format THMs. (4) On the benzene ring, hydroxyl group has the highest activity of forming DBPs, and the second is ketone group; amino-group is play a part of auxiliary forming para, ortho or meta position structure mainly; aldehyde and carboxyl group are inert function group; the function of methyl group is remain to be determined.

Acetic Acid↗
PubMed2006

[Expression and purification of membrane immunogens of Treponema pallidum in Pichia pastoris].

Genes of Treponema pallidum subsp. pallidum three membrane antigens (47kDa, 17kDa and 15kDa) were amplified by PCR with the template of the genomic DNA of Nichols strain and cloned into plasmid pPICZ B, the recombinant plasmids of pTP47, pTP17 and pTP15 were transformed into Pichia pastoris GS115. Recombinant antigens were expressed by the methanol induction and confirmed by the Western blot assay. Fusion antigens with 6 x His tag were purified using Ni-NTA agarose, and purified fusion protein yields were 4.8mg/L, 6.6mg/L and 25mg/L of cell culture for His-TP15, His-TP17 and His-TP47, respectively. Purity of all three antigens were more than 96% by SDS-PAGE assay. Particularly, His-TP17 was more about 6kDa molecular weight than that of expected probably because of glycosylation in Pichia pastoris. At last, these recombinant antigens were evaluated by ELISA assay with serum from syphilis patient and healthy blood donors, all three antigens showed strong sensitivity and specificity. So three membrane antigens of Treponema pallidum were expressed and purified fused with 6 x His tag in Pichia pastoris for the first time. The immunoreactivity results showed that all of which can be applied to diagnosis of Treponema pallidum, especially to diagnosis method based on combined two or three antigens.

Antigens, Bacterial↗
PubMed2005

Synergistic action of famotidine and chlorpheniramine on acetic acid-induced chronic gastric ulcer in rats.

AIM: To assess the synergistic action of famotidine (FMD) and chlorpheniramine (CPA) on acetic acid-induced chronic gastric ulcer in rats. METHODS: Chronic gastric lesions were induced in male Sprague-Dawley (SD) rats by serosal application of the acetic acid. Forty SD rats were randomly divided into blank group (n = 8), control group (n = 8), FMD group (n = 8), CPA group (n = 8), and FMD+CPA group (n = 8). Each group was given intraperitoneally (i.p.) 0.5 mL/100 g distilled water, 9 g/L NaCl saline, 4 mg/kg FMD, 10 mg/kg CPA, 4 mg/kg FMD+10 mg/kg CPA, respectively, daily for 10 d. On d 10, ulcer area was determined by planimetry. The level of myeloperoxidase (MPO) in the liver homogenization was determined by biochemical methods and the plasma levels of 6-ketoprostaglandin F1 alpha (6-keto-PGF(1a)) and IL-8 were determined by radioimmunoassay. RESULTS: The synergistic effects of FMD+CPA group on the lesion, IL-8, 6-keto-PGF(1a) and MPO were confirmed. The effect of FMD+CPA group was significantly different as compared to the control and FMD groups. The lesion (mm(2)) was reduced from 40.18+/-2.6 in control group to 6.83+/-2.97 in PMD+CPA group, P<0.01, and from 32.9+/-3.27 in FMD group to 6.83+/-2.97 in PMD+CPA group, P<0.01. The plasma levels of IL-8 decreased from 0.69+/-0.11 ng/L in control group to 0.4+/-0.04 ng/L in PMD+CPA group, P<0.01, and from 0.51+/-0.08 ng/L in FMD group to 0.4+/-0.04 ng/L in PMD+CPA group, P<0.05. The level of 6-keto-PGF(1a) increased from 7.55+/-1.65 ng/L in control group to 16.62+/-0.97 ng/L in PMD+CPA group, P<0.01, and from 13.15+/-1.48 ng/L in FMD group to 16.62+/-0.97 ng/L in PMD+CPA group, P<0.05. The levels of MPO in the liver homogenate decreased from 9.12+/-2.05 u/L in control group to 4.33+/-0.95 u/L in PMD+CPA group, P<0.01, and from 8.3+/-1.29 u/L in FMD group to 4.33+/-0.95 u/L, P<0.01. CONCLUSION: The synergistic action of FMD and CPA on acetic acid-induced chronic gastric ulcer in rats decreases the incidence of ulcer and also enhances the healing of ulcer.

6-Ketoprostaglandin F1 alpha↗
PubMed2005

Highly enantioselective phenylacetylene addition to aromatic ketones catalyzed by cinchona alkaloid-aluminum complexes.

The catalytic asymmetric addition of phenylacetylene to aromatic ketones is reported. The catalyst, generated from commercially available Cinchona alkaloids and industrially available triethylaluminum, gives the expected tertiary alcohols with good enantiomeric excess (70-89%) and yields (60-83%). No previous case has been reported successfully using triethylaluminum as a Lewis acid in the asymmetric alkynylation of carbonylic derivatives, and thus we provide a new method to obtain optically active tertiary propargyl alcohols.

Acetylene↗
PubMed2005

Total atomic scattering factors for the ground states of the lithium isoelectronic sequence from Na8+ to Ca17+.

In this work, total atomic scattering factors for the ground states of the lithium isoelectronic sequence are calculated by using the full core plus correlation wave function. For the ground state of the lithium atom, our results are compared with the previous theoretical values in the literature; the influence of electron correlation on total atomic scattering factors is analyzed systematically and our results agree with previous configuration interaction calculations very well. For the ground states of the lithium isoelectronic sequence from Na8+ to Ca17+, the general functional behavior of total atomic scattering factors is analyzed together for each state of the isoelectronic sequence.

Journal Article↗
PubMed2005

The synthesis of GoldMag nano-particles and their application for antibody immobilization.

Fe3O4/Au (GoldMag) particles with core/shell structure were synthesized by reduction of Au3+ with hydroxylamine in the presence of Fe3O4. The synthesized particles have an average size smaller than 100 nm in diameter with of superparemagnetic properties due to their Fe oxide cores. The particles show optical features with a plasmon resonance peak from 550, 570 to 590 nm correlating with increasing diameters from 50 nm, 70 nm to 100 nm. The GoldMag particles need only a single step for antibody immobilization and have high binding capacity for antibodies. These advantages permit improved methods of isolating and detecting biomolecules.

Antigen-Antibody Complex↗
PubMed2005

Packaging of gold particles in viral capsids.

In-vitro self-assembly conditions known to result in generating infectious virions have been used in vitro to reassemble bromovirus capsid proteins around negatively charged gold nanoparticles cores. We discuss here the optical properties (elastic light scattering) and the influence of the core size and of the functional moiety on the resulting virus-like particles. Our results indicate that the formation of a closed shell, as opposed to an amorphous protein coat, does occur and that the shell/core interactions can be tuned using different coatings on the nanoparticle core. Such studies may lead to real-time monitoring of viral traffic on the scale of a single virus, as well as to the possibility of chemical sensing along the intracellular and intercellular viral pathways and contribute to a better understanding of the virus transport and cellular compartmentalization.

Bromovirus↗
PubMed2005

Brainstem auditory function at term in preterm babies with and without perinatal complications.

Functional integrity of the auditory brainstem was studied at term in babies born at 30-36 wk of gestation using maximum length sequence brainstem auditory evoked response (MLS BAER). Compared with normal term babies, preterm babies who had perinatal complications showed a tendency of an increase in wave V latency and I-V and III-V intervals at all 91-910/s clicks, with statistical significance at higher rates. Wave V latency and I-V interval increased significantly at 455/s and 910/s. III-V interval increased at all click rates, which was more significant at higher rates. III-V/I-III interval ratio increased at most rates. Waves III and V amplitudes reduced significantly mainly at 455/s and 910/s. In preterm babies who had no perinatal complications, there were no major MLS BAER abnormalities except an increase in III-V interval at 91-910/s. By comparison, the preterm babies with perinatal complications had a significant increase in wave V latency, I-V and III-V intervals, and III-V/I-III interval ratio at 455/s and 910/s clicks. These results suggest that although there are no major abnormalities in brainstem auditory function in preterm babies without perinatal complications, the auditory brainstem, mainly the more central part, in preterm babies with perinatal complications is impaired, which becomes more apparent at very high stimulus rates. We conclude that preterm babies with perinatal complications are at high risk of central auditory impairment.

Brain Stem↗
PubMed2005

[Role of dendritic cells in the pathogenesis of severe pneumonia in children].

OBJECTIVE: Severe pneumonia is one of the common severe diseases in children. Increasing evidences show that immune response greatly contribute to severe pneumonia. Dendritic cells (DC) are the important antigen presenting cells in the lung. To study the role of dendritic cells in development of severe pneumonia in children, the authors measured the number of mature DC in bronchoalveolar lavage fluid (BALF), and evaluated the relationship among IL-12, pro-inflammatory cytokines and clinical scores. METHODS: The following 3 groups of children were enrolled in this study: severe pneumonia group: 27 children with severe pneumonia treated between November 2002 and May 2003 in PICU; mild pneumonia group: 30 children with mild pneumonia in department of pulmonology; control group: 29 children without pneumonia but receiving ventilator treatment for chest surgery. Mature DC in BALF was determined in severe pneumonia group and the control group on the day of tracheal intubation for mechanical ventilation. Acute lung injury scores and severe disease scores were evaluated in children with severe pneumonia and mild pneumonia. All children's serum levels of TNF-alpha, IL-6 and IL-12 were measured by using ELISA within 24 hours after admission. SPSS version 11.5 was used for statistical analysis. RESULTS: (1) The percent of mature DC in children with severe pneumonia was significantly higher when compared with the control group on the first day after ventilation [14.2 (3.9 - 51.8)] vs. [1.3 (0.2 - 22.5)] (Z = 5.44, P < 0.01). (2) In severe pneumonia group, the concentration of serum IL-12 [117.0 (79.9 - 159.4) ng/L], TNF-alpha [90.6 (52.2 - 185.9) ng/L], IL-6 [128.7 (73.3 - 793.8) ng/L] were significantly higher than those in mild pneumonia group where the values were [71.6 (19.4 - 196.8)], [26.6 (2.5 - 113.9)], and [39.9 (7.8 - 82.5)] (P < 0.01), and the control group [6.4 (12.2 - 92.0)], [6.4 (1.8 - 91.9)], and [23.0 (6.4 - 54.2)] (P < 0.01). Serum IL-12, TNF-alpha and IL-6 levels in children with mild pneumonia were higher than those of control group (P < 0.01). (3) The percent of mature DC was increased with the serum level of IL-12 (r = 0.48, P < 0.01), TNF-alpha (r = 0.58, P < 0.01), IL-6 (r = 0.51, P < 0.01) and lung injury scores (r = 0.39, P < 0.05), but it did not correlate with severe disease scores (r = -0.11, P > 0.05). CONCLUSIONS: There is excessive production of pro-inflammatory cytokines and over-stimulation of lung dendritic cells in children with severe pneumonia. Over-stimulation of lung dendritic cells, the increased serum levels of IL-12, TNF-alpha, IL-6 and the severity of pneumonia may suggest that DC plays an important role in pathogenesis of severe pneumonia in children.

Bronchoalveolar Lavage Fluid↗
PubMed2005

[Association of genetic polymorphism of XRCC1 with susceptibility to acute childhood leukemia].

OBJECTIVE: To explore the association between genetic polymorphisms of XRCC1 and susceptibility to acute childhood leukemia. METHODS: A case-control study with 63 childhood leukemia patients and 66 control subjects was conducted to investigate the role of three XRCC1 polymorphisms (c. 194, c. 280 and c. 399 ) on susceptibility to childhood leukemia. Genotyping was performed using Polymerase chain reaction-restrained fragment length polymorphism technique (PCR-RFLP) to detect the single nucleotide polymorphisms (SNPs) of XRCC1 gene. RESULTS: There was a 2.235-fold increased risk of childhood leukemia for individuals carrying XRCC1c. 399 Gin allele (95% CI 1.038 - 4.812) compared with subjects carrying Arg/Arg allele, and the OR among boys was 3.110 (95% CI 1.235 - 7.831). No interaction was found between X-ray exposure and XRCC1 polymorphisms using Logistic regression analysis. CONCLUSION: Polymorphism of XRCC1 gene may contribute to the higher risk of childhood leukemia.

Acute Disease↗
PubMed2005

[Optimal process combination for control of disinfection by-products and precursors].

It is compared that the efficiency of control disinfection by-products and their precursors by sequential-chlorination disinfection and traditional free chlorination disinfection following different processes combination. Compared with traditional chlorination, sequeutial chlorination, i. e. short-term free chlorine plus chloramine disinfection can lower 35.8% - 77.0% of trihalomethane formation and 36.6% - 54.8% of haloacetic acids formation. Moreover, the poorer the influent quality is, the more advantages sequential chlorination disinfection have over free chlorination disinfection. The formation of trihalomethane and haloacetic acids by sequential chlorination following the simplest traditional process is even less than their formation by free chlorination following the most complex process, pre-ozonization plus traditional one and ozonization-active carbon process. The results show that ozonization-active carbon process and pre-ozonization have better efficiency on control of disinfection by-products and their precursors. We recommend that water plants apply the sequential chlorination disinfection and ozonization-active carbon process.

Acetic Acid↗
PubMed2005

[Determination of positive bronchodilating response using impulse oscillation system in children].

OBJECTIVE: Impulse oscillation system (IOS) as an approach to lung function determination is suitable for children, especially for preschool children in that it only requires the individual to be examined to breathing stably with tidal volume. However, until now there have been no uniformly agreed criteria for positive bronchial reversibility test in clinical practice. A screening method was applied to seek for answer when this question in the hope of providing objective evidence for clinical diagnosis of respiratory diseases, esp. asthma. METHODS: One hundred and fifty-six children patients during asthma attack were recruited randomly for this study from January to December, 2004. These patients included 103 boys and 53 girls aged from 5 to 18 years with mean age of 8.84 +/- 2.58 years, who visited the doctors in the Clinical and Educational Centre for Asthma, Capital Institute of Pediatrics and were diagnosed as asthma. Maximal expiratory flow volume and IOS lung function were determined followed by bronchodilator reversibility test in all patients. The sensitivity and specificity of IOS parameters, total respiratory impedance (Zrs), respiratory resistance at 5 Hz (R5) and reactance at 5 Hz (X5) for diagnosing asthma at different improvement levels after inhalation of bronchodilator were calculated respectively using forced expiratory volume in first second (FEV(1)) and maximal mid-expiratory flow (MMEF) as gold standard. And the regression equation between parameters of lung function which were determined with the two different methods was analyzed. RESULTS: After inhalation of bronchodilator, the lung function of the children was improved significantly (P < 0.01), with the FEV(1), MMEF increase and Zrs, R5, and X5 decrease. There were significantly positive correlations (P < 0.01) between the improvement rate of parameters of lung functions determined with the two methods, and the highest correlation coefficients existed between X5 and FEV(1) and MMEF (respectively 0.676, 0.571), correlation coefficients between X5 and Zrs ranked second (0.519 and 0.505, respectively). When an increase of FEV(1) equal to or greater than 15%, or increase of MMEF equal to or greater than 30% was used as reference for positive bronchial reversibility, the sensitivity and specificity were relatively high for considering positive bronchial reversibility test with at least 20% decrease of Zrs, R5, and 30% decrease of X5 with IOS lung function. The sensitivity and specificity of Zrs, R5 and X5 calculated from FEV(1) were 0.62, 0.51; 0.49, 0.54; 0.70, and 0.54, respectively. The sensitivity and specificity of Zrs, R5 and X5 calculated from MMEF were 0.63, 0.54; 0.53, 0.60; 0.60, and 0.58, respectively. The regression equation showed that the decrease of Zrs, R5 and X5 corresponding to 15% increase of FEV(1) and 30% increase of MMEF were 21.7%, 21.3%; 19.9%, 19.5%; 30.1%, and 29.6%, respectively. CONCLUSION: When lung function is determined with IOS in children, only when decrease of Zrs and R5 is equal to or more than 20% and decrease of X5 is 30% or more after inhalation of bronchodilator, can the bronchial reversibility test be considered as positive.

Adolescent↗
PubMed2005

[Life table of natural Bemisia tabaci population on cucumber plants in different seasons].

The study showed that in the early growth stage of cucumber in spring, the predation on Bemisia tabaci egg was the key factor for controlling B. tabaci population, and the exclusion index of population control was 1.7333. In the late growth stage of cucumber in spring, summer and autumn, the predation on B. tabaci elder nymph was the critical factor for controlling B. tabaci population, and the exclusion index of population control was 4.5372, 4.0429 and 7.9021, respectively. From spring to autumn, the index of population development trend was decreased from 21.0610 to 5.8523, because of the increasing controlling effect of the predators, and the exclusion index of population control was from 4.0560 to 17.8662.

Animals↗
PubMed2004

Quadrupole and octupole polarizabilities for the ground states of lithiumlike systems from Z=3 to 20.

The quadrupole and octupole polarizabilities for the ground states of lithiumlike systems from Z=3 to 20 are calculated with the full-core plus correlation method. For the neutral lithium atom, the typical patterns of convergence of the quadrupole and octupole polarizabilities are analyzed. The calculated quadrupole and octupole polarizabilities of the ground state for lithium atom are compared with the previous theoretical results obtained by other methods; our predictions agree with the most accurate reports in the literature very well. For lithiumlike ions, our prediction may provide valuable reference data for other accurate theoretical calculations in future.

Journal Article↗