Alginate encapsulation is a highly reproducible method for tumor cell implantation in dorsal skinfold chambers.
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Alginates↗
Biomedical subjects
Qing Chen
Publications and source records attributed to Qing Chen.
[A field trial for evaluating the safety of recombinant human interferon alpha-2b for nasal spray].
OBJECTIVE: To evaluate the safety of recombinant human interferon alpha-2b for nasal spray for the prevention of SARS and other upper respiratory viral infections. METHODS: Field epidemiologic evaluation was conducted, the design was randomized and had a synchronously parallel control group. In the study, the drugs were given for five days and all subjects were followed up for ten days. RESULTS: During the period of using interferon, body temperature of the experimental group was normal compared to the control group. Experimental group had more influenza-like symptoms than the control group (P < 0.05), such as headache (4.83%-7.09%), dizziness (7.17%-11.63%), lassitude (8.55%-15.06%), muscular soreness (4.43%-7.09%), pharynx dryness (12.10%-17.85%), angina (6.25%-8.72%), abdominal pain (2.30%-5.50%) and diarrhea (2.45%-5.66%). Most of side effects reached their peak with in the first 3 days. Except for pharynx dryness, the incidences of all other side effects declined after completion of the use of the trial drug, and incidences of some symptoms in experimental group were lower than those of the control group. There were no significant differences in the symptoms of cough and expectoration between the experimental group and the control group. The incidence of exanthem in the control group was significantly higher than that in the experimental group. The side effect of bloody nasal mucus was not observed in experimental group, which had been reported by other authors in several volunteer studies. CONCLUSION: Using recombinant human interferon alpha-2b for nasal spray could lead to some influenza-like symptoms, however, all those symptoms were mild , reversible, and relieved after completion of the use of the trial drug. No serious side effects were found during the period of following up. The authors conclude that the drug is safe.
Abdominal Pain↗
[A field trial of recombinant human interferon alpha-2b for nasal spray to prevent SARS and other respiratory viral infections].
OBJECTIVE: To study the preventive effect of recombinant human interferon alpha-2b for nasal spray against SARS and other common respiratory viral infections by serum-epidemiological method. METHODS: A randomized, placebo-controlled, double-blind field trial study in populations with 14,391 persons from SARS prevalent cities or provinces in China during May-Jun, 2003 and Dec-Apr, 2004. Interferon alpha-2b was given twice per day, once 9 x 10(5) IU by nasal spray for 5 days. Serum samples were taken at 15 days after last administration. Serological tests included SARS IgG antibody and IgM antibodies against influenza B, parainfluenza virus types 1-3, adenovirus type 3, 7 and respiratory syncytial virus by using commercial ELISA kits. RESULTS: No statistically significant difference in serum SARS IgG antibody positive rate was found between the interferon and control groups among 2,757 serum samples. On the other hand, after using interferon, all four respiratory viruses (parainfluenza virus types 1-3 influenza B, adenovirus types 3, 7 and respiratory syncytial virus) in interferon group had lower IgM antibody positive rates than those in control group. Among them there were statistically significant differences between the interferon and control groups for parainfluenza virus, influenza B and adenovirus. The preventive efficacy of interferon against four respiratory viruses was different, from high to low, the rank was Flu B (66.76%), parainfluenza types 1-3 (66.75%), RSV (39.61%) and adenovirus (32.86%). The average preventive efficacy was 50.27%. CONCLUSION: The recombinant human interferon alpha-2b for nasal spray could decrease the rates of common respiratory viruses infection in the selected population.
Administration, Intranasal↗
[Molecular epidemiology of diarrhea among children with Norwalk-like virus in a hospital of Guangzhou in autumn and winter].
OBJECTIVE: To explore the epidemiological characteristics of Norwalk-like virus (NLVs) infection in children with diarrhea and to study the genotype and predominant cluster at a hospital in Guangzhou city. METHODS: Fecal specimens from 358 children with acute gastroenteritis from October 2003 to January 2004 and information about the cases were collected. NLVs was detected from the specimens by reverse transcription-polymerase chain reaction (RT-PCR) and the PCR products were purified and sequenced. RESULTS: Forty-two positive specimens were detected from the 358 fecal specimen with a positive rate of 11.73% (42/358). Of these, 40 specimens were obtained from infants younger than 3 years of age. The youngest infant infected with NLVs in this study was only 25 days. The positive rate in November (17.27%) was the highest. Eleven positive PCR products were selected and sequenced. Nucleotide sequence analysis revealed that 11 strains all belong to genogroup II (G II), and of these, 5 strains belonged to G II-3 cluster, with another 5 strains belonged to G II-4 cluster. However, one strain with its cluster could not be determined. CONCLUSION: NLVs served as one of the important pathogens causing sporadic acute gastroenteritis among children at a hospital in Guangzhou. The predominant strains were identified as G II-3 and G II-4 cluster.
Age Distribution↗
[Summary of Guangdong provincial seminar on avian influenza and influenza].
On 8th November 2005, an academic seminar on avian influenza and influenza in Guangdong Province was held by Guangdong Society of Tropical Medicine and the Epidemiology Committee of the Guangdong Preventive Medicine Society in Southern Medical University, addressing the current problems in epidemics of avian influenza. The specialists attending the conference arrived at the common consideration that at present, the avian influenza virus H5N1 has not the capacity to trigger an pandemic in human population, but scattered cases had been reported to increase the suspicions of H5N1 virus transmission between humans. Due attention should be paid to the tendency of expansion of the host range and epidemic area, and the possibility of disastrous influenza pandemic among human populations persists, for which rational consideration is called for, and the role of specialists should be fully recognized who are endeavoring to examine the possible scale of influenza occurrence and devise strategy to deal with the epidemic in Guangdong province according to the practical situation in China. Increased funds and investment in scientific research on avian influenza is urged for influenza prediction and surveillance, rapid and early diagnostic assays, understanding of virus variation, mechanism of H5N1 virus adaptation to human hosts, effective medicines and vaccines for prevention and therapy of avian influenza. Laboratory bio-safety control should be enforced to prevent infections originated from laboratories. The specialists appeal that the media report the news objectively and issue the public warnings against avian influenza after consulting specialists, so as to avoid unnecessary social panic.
Animals↗
[Purging effects of CD3AK/iNOS in vitro on primary leukemic cells from chronic myeloid leukemia patients].
To investigate the purging effect of CD3AK/iNOS on primary leukemic cells from chronic myeloid leukemia patients in vitro, amphotropic packaging cell line PA317 transfected with the whole length of iNOS gene was cultivated, amplified and screened by G418. The viral titer was determined by the NIH3T3 cells. Human peripheral blood mononuclear cells were isolated and activated by anti-CD3 monoclonal antibody in vitro. CD3AK cells were incubated with viral supernatant and selected by G418. Resistant clones were assayed for iNOS gene expression by RT-RCR. The content of nitric oxide and the activity of iNOS in the culture supernatant of CD3AK/iNOS were evaluated by the method of Griess. After BMMNC or PBMNC from CML patients were co-cultured with CD3AK/iNOS, CD3AK/Neo and CD3AK/iNOS respectively, the expression of bcr/abl fusion gene was detected by serial dilution semi-quantitative net RT-PCR assay. The results showed that anti-G418 positive packaging cell line PA317 transfected with the whole length of iNOS gene clones could stably synthesize and excrete recombinant retroviral vectors. The titer of recombinant retroviral vectors was 1.0 x 10(5) CFU/ml. After being transfected by recombinant retroviral supernatant, the iNOS cDNA was expressed in CD3AK/iNOS. The content of NO and activity of iNOS that synthesized and excreted by CD3AK/iNOS were notably increased, compared with those of CD3AK. There were statistically significant differences in NO content and iNOS activity between two groups. After BMMNC or PBMNC from CML patients were co-cultured with CD3AK/iNOS, CD3AK/Neo and CD3AK/iNOS respectively, the expression of bcr/abl fusion gene in all of them was down-regulated by serial dilution semi-quantitative RT-PCR assay. It is concluded that construction of CD3AK/iNOS can markedly increase the content of NO and the activity of iNOS, which can be more efficient in in vitro purging leukemia cells for autologous hematopoietic stem cell transplantation.
Adult↗
A yeast two-hybrid technology-based system for the discovery of PPARgamma agonist and antagonist.
Peroxisome proliferator-activated receptor gamma (PPARgamma) is an important therapeutic drug target against several diseases such as diabetes, inflammation, dyslipidemia, hypertension, and cancer. Ligand binding to PPARgamma is responsible for controlling the biological functions, and developing new technology to measure ligand-PPARgamma binding is significant for both the function study of the receptor and ligand discovery. In this study, we exploited an efficient approach for the discovery of PPARgamma agonist and antagonist via a yeast two-hybrid system based on the fact that PPARgamma interacts with the coactivator CBP (CREP-binding protein) ligand-dependently. We employed the MEL1 reporter gene instead of the traditionally used LacZ gene to evaluate the protein-protein interactions by conducting a convenient alpha-galactosidase assay in the yeast strain AH109 with genes of PPARgamma-LBD (ligand-binding domain) and CBP N terminus introduced. With this built screening platform, the EC(50) values of the PPARgamma agonists rosiglitazone, troglitazone, pioglitazone, indomethacin, 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)), and GI262570 were investigated, and the quantitatively antagonistic effect by IC(50) of the PPARgamma typical antagonist GW9662 on the rosiglitazone agonistic activity was fully examined. The reliability of this presented system evaluated by the comparable agreement of EC(50) and IC(50) values for the test compounds with the reported ones indicated that this yeast two-hybrid-based approach is powerful for PPARgamma agonist and antagonist screening. In addition, because this screening system is designed for use in a microtiter plate format where numerous chemicals could be readily screened, it is hoped that this yeast two-hybrid screening approach may be adaptable for high-throughput settings.
Anilides↗
Effect of quinidine on the 10-hydroxylation of R-warfarin: species differences and clearance projection.
Stimulation by quinidine of warfarin metabolism in vitro was first demonstrated with liver microsomal preparations. We report herein that this drug interaction is reproducible in an animal model but that it exhibits profound species differences. Thus, using rabbit liver microsomes and a kinetic model incorporating two binding sites, the hepatic intrinsic clearance of R-warfarin via the 10-hydroxylation pathway (CL(int)(W)) was projected to be 6 +/- 1 and 128 +/- 51 microl/min/g liver, respectively, in the absence and presence of 21 microM unbound quinidine. These estimates were consistent with the results from studies in which rabbit livers (n = 5) were perfused in situ with R-warfarin or R-warfarin plus quinidine. The CL(int)(W) increased from 7 +/- 3 to 156 +/- 106 microl/min/g liver after increasing the hepatic exposure of unbound quinidine from 0 to 21 microM. In contrast, when liver microsomes or intact livers from rats were examined, R-warfarin metabolism was inhibited by quinidine, the CL(int)(W) decreasing to 26% of the control value after exposure of perfused rat livers (n = 5) to 22 microM unbound quinidine. The third example involved monkey liver microsomes, in which the rate of 10-hydroxylation of R-warfarin was little affected in the presence of quinidine (<2-fold increase). In all three species, the 10-hydroxylation of R-warfarin was catalyzed primarily by members of CYP3A, based on immuno- and chemical inhibition analyses. These findings not only highlight the variability of drug interactions among different species but also suggest that changes in hepatic clearance resulting from stimulation of cytochrome P450 activity may be projected based on estimates generated from corresponding liver microsomal preparations.
Animals↗
Suppression of angiogenesis and tumor growth by selective inhibition of angiopoietin-2.
Angiopoietin-2 (Ang2) exhibits broad expression in the remodeling vasculature of human tumors but very limited expression in normal tissues, making it an attractive candidate target for antiangiogenic cancer therapy. To investigate the functional consequences of blocking Ang2 activity, we generated antibodies and peptide-Fc fusion proteins that potently and selectively neutralize the interaction between Ang2 and its receptor, Tie2. Systemic treatment of tumor-bearing mice with these Ang2-blocking agents resulted in tumor stasis, followed by elimination of all measurable tumor in a subset of animals. These effects were accompanied by reduced endothelial cell proliferation, consistent with an antiangiogenic therapeutic mechanism. Anti-Ang2 therapy also prevented VEGF-stimulated neovascularization in a rat corneal model of angiogenesis. These results imply that specific Ang2 inhibition may represent an effective antiangiogenic strategy for treating patients with solid tumors.
Angiopoietin-2↗
Central role of IL-6 receptor signal-transducing chain gp130 in activation of L-selectin adhesion by fever-range thermal stress.
The physiological benefit of the febrile response is poorly understood. Here we show that fever-range thermal stress enhances the function of the L-selectin lymphocyte homing receptor through an interleukin-6 (IL-6)-dependent signaling mechanism. Thermal stimulation of L-selectin adhesion in vitro and in vivo is mediated by engagement of the gp130 signal-transducing chain by IL-6 and a soluble form of the IL-6 receptor-alpha (sIL-6Ralpha) binding subunit. Thermal control of adhesion is maintained in IL-6-deficient mice through a gp130-dependent compensatory mechanism mediated by IL-6-related cytokines (i.e., oncostatin M [OSM], leukemia inhibitory factor [LIF], and IL-11). Combined biochemical and pharmacological inhibitor (PD98059, U0126, SB203580, SP600125) approaches positioned MEK1/ERK1-2, but not p38 MAPK or JNK, in the IL-6/sIL-6Ralpha signaling pathway upstream of activation of L-selectin/cytoskeletal interactions and L-selectin avidity/affinity. These results highlight a role for gp130-linked IL-6/sIL-6Ralpha transsignaling in amplifying lymphocyte trafficking during febrile inflammatory responses.
Animals↗
Acute diarrhea during army field exercise in southern China.
AIM: During emergency period, infectious diseases can be a major threat to military forces. During field training in southern China, diarrhea is the main cause of nonbattle injury. To evaluate the causes of and risk factors for diarrhea in emergency period, we collected clinical and epidemiological data from the People's Liberation Army (PLA) during field training in southern China. METHODS: From September 25 to October 2 1997, 2636 military personnel were investigated. Fecal sample cultures for lapactic pathogens were obtained from 103 military personnel with diarrhea. In addition, a questionnaire was administered to 103 cases and 206 controls to evaluate the association between illness and potential risk factors. At the same time, another questionnaire of 1:4 case-case control was administered to 22 severe cases (each severe case paired 4 mild cases). RESULTS: The training troop's diarrhea incidence rate was significantly higher than that of garrison. The diarrhea incidence rate of officers was significantly lower than that of soldiers. A lapactic pathogen was identified in 63.1% (65/103) of the troops with diarrhea. Enterotoxigenic Escherichia coli (35.0%) and plesiomona shigelloides (16.5%) were the most common bacterial pathogens. All bacterial isolates were sensitive to norfloxacin and ceftazidine. However, almost all of them were resistant to sulfamethoxazole, trimethoprim-sulfamethoxazole, oxytetracycline, doxycycline, furazolidone, ampicillin and cloromycetin to a different degree. Risk factors associated with diarrhea included drinking raw water, eating outside, contacting diarrhea patients, lacking sanitation, depression, lacking sleep, which were established by multiple-factor logistic regression analysis. In addition, the unit incidence rate was associated with the density of flies and the average daily boiled water available by regression and discriminate analysis. CONCLUSION: A series of risk factors are associated with the incidence rate of diarrhea. Our results may provide a useful basis for prevention and cure of diarrhea in emergency period of PLA.
Acute Disease↗
Dynamics of intestinal flora after oral vaccination with inactivated whole-cell/recombinant B subunit O139 cholera vaccine.
OBJECTIVE: To investigate the change of intestinal flora in subjects receiving oral vaccination with inactivated whole-cell/recombinant B subunit (WC/rBS) O139 cholera vaccine made in China. METHODS: The fecal smears of 5 groups of subjects receiving the vaccine were collected before and 2 and 3 months after the vaccination to examine the distribution of the intestinal flora. RESULTS: In the 458 specimens examined, the total amount of bacteria and percentages of G+b, G+c and G-c were decreased whereas the amount of G-b significantly increased after vaccination. Compared with the placebo control group, the vaccinated groups exhibited significant changes in G+b and G-c, which also varied significantly between the group receiving 3 doses of WC/rBS vaccine and the other vaccinated groups. The vaccination produced distinct changes in the percentage of the intestinal flora at different time points, showing the most obvious effect on G-b. Oral vaccination was shown to affect the percentage of the intestinal flora very likely through its effect on the amount of G-b. The percentages of G+b, G-b and G-c varied significantly between male and female subjects after vaccination. CONCLUSION: Oral vaccination with WC/rBS affects the intestinal flora in human, and the mechanism as well as the implications needs to be further explored.
Administration, Oral↗
[Effects of millimeter wave on gap junctional intercellular communication in human keratinocytes].
OBJECTIVE: To explore the effect of millimeter wave (MW) at low power density on gap junctional intercellular communication (GJIC) in human keratinocytes (HaCaTs). METHODS: Fluorescence recovery after photobleaching (FRAP) technique was employed to determine effect of 30.16 GHz MW exposure at 1.0 and 3.5 mW/cm(2) on GJIC with laser confocal scanning microscope. RESULTS: FRAP analysis revealed that 12-O-tetradecanoylphorbol-13-acetate (TPA) at a dose of 5 microg/L could inhibit GJIC in HaCaTs. Fluorescence recovery rate fell from (55 +/- 17)% in the controls to (34 +/- 13)% after photobleaching, with a very significant difference (P < 0.001). Exposure to MW alone for one hour at either 1.0 mW/cm(2) or 3.5 mW/cm(2) did not affect GJIC, with fluorescence recovery rates of (52 +/- 16)% and (50 +/- 17)%, respectively. GJIC suppression induced by TPA was weakened by MW combined with 5 microg/L TPA treatment for one hour, which could be partially recovered by exposure to 1.0 mW/cm(2) MW with fluorescence recovery rate of (47 +/- 16)%, P < 0.01, and fully recovered by exposure to 3.5 mW/cm(2) MW with fluorescence recovery rate of (50 +/- 16)%, P < 0.001, with a very significant difference. CONCLUSIONS: GJIC suppression induced by TPA could be eliminated or diminished by exposure to millimeter wave in HaCaTs.
Cell Communication↗
[Renaturation of thermolabile hemolysin inclusion bodies expressed by Vibrio parahaemolyticus].
OBJECTIVE: To clone and construct expression vector pET32a+-tlh to acquire biologically functional thermolabile hemolysin of Vibrio parahaemolyticus. METHODS: tlh gene was cloned and the expression vector pET32a+-tlh constructed. The tlh gene of Vibrio parahaemolyticus was expressed in DE3 in the form of inclusion body, which was resolved in 8 mol/L urea followed by purification of the fusion protein using affinity chromatography and renaturation through gradient dialysis, protein concentration reduction and oxidoreduction. RESULTS AND CONCLUSION: The purified and renatured protein possessed hemolytic and immunogenic activities.
Cloning, Molecular↗
[Bioinformatic analysis of Vibrio parahaemolyticus thermolabile hemolysin gene].
OBJECTIVE: To carry out bioinformatic analysis of Vibrio parahaemolyticus thermolabile hemolysin gene (tlh) obtained by PCR amplification. METHODS: The tlh gene amplified by PCR was cloned into the vector pET32a(+) and sequenced, followed by analysis of the biological information by with presenting the sequences to the websites of bioinformatics on the Internet. RESULTS AND CONCLUSIONS: The sequenced tlh gene (named tlh14-90) was entered into GenBank with the accession number of AY289609. Tlh14-90 has a length of 1 257 bp with both start and stop codons, having 99% homology with the tlh gene of WP1. Tlh14-90 is predicted to encode a protein containing 418 amino acids (named TLH14-90, with the molecular formula of C(2131)H(3184)N(548)O(649)S(16), molecular weight of 47 392.9, and the theoretical PI of 4.92). This protein consists of 4 Cys and the contents of Ala, Leu and Asn are 11.0%, 7.4% and 7.2%, respectively, having a hydrophobic parameter of -34 calculated using kappa-D method. Predicted as a alpha/protein for its secondary structure, TLH14-90 has not been identified for its tertiary structure.
Bacterial Proteins↗
Targeting tumor microvessels using doxorubicin encapsulated in a novel thermosensitive liposome.
Liposomal drugs accumulate only in perivascular regions in tumors after i.v. injection. Thus, they cannot kill tumor cells in deeper tissue layers. To circumvent this problem, we investigated effects of doxorubicin (DOX) encapsulated in a lysolecithin-containing thermosensitive liposome (LTSL) on tumor microcirculation because damaging microvessels would stop nutrient supply to deeper tumor cells. We used LTSL-DOX in combination with hyperthermia to treat a human squamous carcinoma xenograft (FaDu) implanted in dorsal skinfold chambers in nude mice. Before the treatment, the RBC velocity in tumors was 0.428 +/- 0.037 mm/s and the microvascular density was 3.93 +/- 0.44 mm/mm(2). At 24 hours after the treatment, they were reduced to 0.003 +/- 0.003 mm/s and 0.86 +/- 0.27 mm/mm(2), respectively. The same treatment, however, caused only 32% decrease in the RBC velocity and no apparent change in microvascular networks in normal s.c. tissues over the same period. LTSL and LTSL-DOX alone had no effect on tumor microcirculation, and LTSL plus hyperthermia caused only a transient decrease in the RBC velocity in tumors. At 24 hours after treatments, tumor microcirculation in all these control experiments was insignificantly different from that before the treatments. We also examined apoptosis of cells in tumors at different time points after LTSL-DOX plus hyperthermia treatment and observed few apoptotic cells in tumor microvessels. In conclusion, the rapid release of DOX during hyperthermia could make the drug to shutdown tumor blood flow while have only minor effects on normal microcirculation in s.c. tissues.
Animals↗
[Detection and sequence analysis of Sapporo-like virus in Guangzhou].
OBJECTIVE: To verify the presence of Sapporo-like virus (SLV) in children with diarrhea in Guangzhou. METHODS: Stool specimens were collected from children with diarrhea treated in the Department of Pediatrics of Nanfang Hospital in autumn and winter, 2003, and semi-nested reverse transcriptase-polymerase chain reaction (RT-PCR) was employed for SLV detection, the positive product of which was sequenced and analyzed in comparison with the SLV sequences documented in GenBank. RESULTS: Only one positive specimen (CH03354) was found out of the 169 stool specimens collected. Sequence analysis of the capsid gene of this strain showed that it belonged to SLV GI-1 cluster. CONCLUSION: SLV exists in Guangzhou and different regions of China may have different genotypes of this virus.
Base Sequence↗
[A prospective cohort study on the comparison of risk of occupational dust exposure and smoking to death].
OBJECTIVE: To compare the effects of dust exposure and smoking on mortality. METHODS: Based on the Guangzhou Occupational Health Surveillance Record System established in 1989-1992, 80 987 factory workers, aged > or = 30, occupationally exposed to dust and non-exposure to dust, were included in a prospective cohort study. RESULTS: (1) The mean age of the cohort was 43.5. Most subjects were workers, with secondary education, and married. Out of them 16.3% having ever exposed to dust, 43.7% ever smoked and 33.5% drank alcohol. (2) The cohort were traced for 8 years on average, but 35 were lost for follow-up. Malignant neoplasm was most commonly seen among 1539 deaths. (3) The adjusted relative risk (RRs) of death of all causes, malignant neoplasm and cerebro-cardiovascular diseases for dust exposed workers were close to those for smokers. However, the adjusted RRs of death of nasopharynx cancer and respiratory system diseases for dust exposed workers were higher than those for smokers. The adjusted RRs of death of lung cancer and stomach cancer for smokers were 2.2 times and 1.5 times of that for dust exposed workers respectively. Dust exposure combined with smoking caused significantly higher death RR. (4) In males, the adjusted RRs of death of all causes, malignant neoplasm and respiratory system diseases for silica dust exposed workers and the adjusted RR of death of cerebro-cardiovascular diseases for wood dust exposed workers were higher those in smokers. (5) The population attributable risk percentage (PARP) of all causes of death for smokers was 2.5 times of that for dust exposed workers. (6) In males, the risks of death for all causes, malignant neoplasm, lung cancer and stomach cancer increased with the amount of smoking per day and the duration of smoking. The risks of death caused by coronary heart disease and respiratory system diseases were increasing with the amount of smoking per day and the duration of smoking respectively. CONCLUSIONS: The adjusted RRs for dust exposed workers were close to those for smokers with dust exposure and smoking having synergistic effects. Some of the adjusted RRs for smokers were higher than those for dust exposed workers PARP for smokers was higher than that for dust exposed workers. Our findings suggested that there was a significant dose-effect between smoking and risk of deaths.
Adult↗