PubMed Health⌕ Search

Biomedical subjects

Q Cheng

Publications and source records attributed to Q Cheng.

At least 55 records · Page 3Linked to original sources
PubMed2001

Microsatellite polymorphism in tsetse flies (Diptera: Glossinidae).

In sub-Saharan Africa, tsetse flies are the vectors of trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals. Certain wild populations of the palpalis group exhibit intraspecific variation and are suspect of manifest differences in vectorial capacity. The current study reports the identification of 13 polymorphic microsatellite loci from Glossina palpalis palpalis Robinean-Desvoidy. The majority of these markers amplify corresponding loci from the related species C. p. gambiensis Vanderplank, G. f. fuscipes Newstead, and G. tachinoides Westwood. Only seven of 13 loci were amplified from G. austeni Newstead. Genetic variability was estimated in one field population of G. p. gambiensis. These results confirmed that microsatellite markers may be used to examine the subpopulation structure of tsetse flies.

Alleles↗
PubMed2001

Increased nitric oxide in peritoneal fluid from women with idiopathic infertility and endometriosis.

OBJECTIVE: To verify whether nitric oxide in peritoneal fluid is associated with endometriosis and infertility. STUDY DESIGN: Twenty-five women with idiopathic infertility and 38 with endometriosis were recruited, and 18 cases of uterine myomata and 2 cases of ovarian cyst served as controls. Peritoneal fluid samples were aspirated from the pouch of Douglas during laparoscopy or laparotomy. Metabolites of nitric oxide (nitrite and nitrate) in peritoneal fluid were determined by a method using nitrate reductase and the Griess reaction. RESULTS: Peritoneal concentrations of nitrate/nitrite in both infertile women (42.02 +/- 12.98 mmol/L) and patients with endometriosis (41.75 +/- 16.42 mmol/L) were significantly higher than that in controls (33.96 +/- 13.07, P < .05 for both). No significant difference in peritoneal nitrate/nitrite level was found between infertile women and patients with endometriosis (P > .5). Peritoneal levels of nitrate/nitrite were comparable among patients with endometriosis at different stages (P > .5). Patients with endometriosis had more peritoneal fluid than controls and idiopathic infertile women, while controls and idiopathic infertile women had comparable amounts of peritoneal fluid. CONCLUSION: An increased peritoneal level of nitric oxide is a common alteration in endometriosis, endometriosis-associated infertility and idiopathic infertility and may be associated with the pathogenesis of these diseases.

Adult↗
PubMed2001

[Expression of endometrial leukaemia inhibitory factor gene in patients with unexplained infertility].

OBJECTIVE: To investigate the expression of endometrial leukaemia inhibitory factor(LIF) gene in patients with unexplained infertility. METHODS: By a quantitative reverse transcription-polymerase chain reaction (RT-PCR), the expression of LIF gene on endometrium during mid-luteal phase was detected in 35 unexplained infertility (infertility group) cases and 20 infertile cases due to tubal obstruction or male factor (control group). RESULTS: The level of LIF mRNA expression on endometrium during mid-luteal phase in infertility group was 0.448 +/- 0.239, significantly lower than those in the control group (1.093 +/- 0.761, P < 0.01). CONCLUSIONS: Our findings suggested LIF might play an important role in the process of implantation. The decreased expression of LIF gene might be one of the major causes of unexplained infertility.

Embryo Implantation↗
PubMed2001

[Retrospective analysis of endometrial neoplasms treated by different therapeutic modalities].

OBJECTIVE: To compare the therapeutic effects of different remedies in patients with endometrial carcinoma. METHODS: Total of 386 patients with metracarcinoma underwent 3 different treatments: (1) operation only 145 cases; (2) operation and complemental radiotherapy 161 cases; (3) radiotherapy only 80 cases. Then they were followed up for 5 years and more. RESULTS: The 5-year survival rates of operation group were 78.9% (56/71), 61.0% (25/41) and 18.2% (6/33) in stage I, stage II, and stage III-IV respectively, for operation and complemental radiotherapy, they were 75.0% (33/44), 59.5% (44/74) and 48.8% (21/43), for radiotherapy, 34.8% (8/23), 18.8% (3/16) and 0.0% (0/41). There was no difference between operation group and operation plus radiotherapy in patients with stage I and stage II (P > 0.05). However the 5-year survival rates were significantly higher in operation plus complemental radiotherapy group and those only received operation in stage III stage IV patients (P < 0.001). And no matter in what stages, the therapeutic effect was worse in radiotherapy group than other two groups (P < 0.001). CONCLUSION: The remedies with operation as main measure are the best choice for metacarcinoma, radiotherapy merely is fit with those who can not be operated on.

Adult↗
PubMed2001

[Changes serum level of tumor specific growth factor and their clinical significance in mechanical trauma patients].

OBJECTIVE: To investigate the post-traumatic changes in the serum level of tumor specific growth factor (TSGF) and their relationship with Injury Severity Score and to inquire into the possible mechanism and clinical significance. METHODS: Fifty patients with mechanical trauma were eligible and included. According to the standard of Injury Severity Score (ISS), the patients were divided into there groups: mild degree group, (ISS < or = 16, n = 31) severe degree group (16 < ISS < 25, n = 13) extreme severe degree group (ISS > or = 25, n = 6). The blood samples of all patients were obtained within 24 hours, and those of 25 dynamically observed patients were obtained on days 3, 5, 7, 9 and 12. RESULTS: The serum level of TSGF was significantly higher in patients with trauma in different groups (P < 0.05). The dynamical observation showed that the index demonstrated curve changes with increase in early stage and decrease later. the climax of TSGF appeared on 7 day in all 3 groups. The TSGF serum levels in extremely severe degree and severe degree groups > mild degree group on days 5, 7, 9 and 12 day (P < 0.05). CONCLUSION: TSGF has relationship with the inflammatory response and recovery of trauma.

Adult↗
PubMed2001

[Bcl-2, p53 expression and Epstein-Barr virus infection in primary nasopharyngeal carcinoma].

OBJECTIVE: To observe bcl-2, p53 gene expression and Epstein-Barr virus (EBV) infection and their relationship with clinicopathologic factors in primary nasopharyngeal carcinoma (NPC). METHOD: p53, bcl-2 proteins were assayed with immunohistochemical technique and EBV were assayed with polymerase chain reaction in 54 cases of NPC and 13 cases of chronic inflammation of nasopharyngeal epithelium (CINE). RESULT: The expression of p53, bcl-2 proteins and EBV were found respectively in 1(7.7%), 3(23.1%) and 1(7.7%) of 13 CINEs, which were significantly lower than those in 54 NPCs with respectively 41(75.9%), 48(88.9%) and 47(87%) (P < 0.01). In 39 cases of 54(72.2%) NPCs, we could find simultaneous p53, bcl-2 expression and EBV infection, furthermore, p53 and bcl-2 expression were significantly positively correlated with each other (r = 0.78, P < 0.01). p53 gene expression was significantly correlated with cervical lymph node metastasis of NPCs (P < 0.01). The expression of p53 in stage II, III, IV (92.9%, 78.9% and 100% respectively) were significantly higher than that in stage I (38.5%) (P < 0.01). CONCLUSION: The expression of p53, bcl-2 gene and EBV infection are the useful factors in the diagnosis of NPC, the overexpression of p53 is related with the stage and cervical lymph node metastasis of NPC, all the three play important roles in the pathogenesis of nasopharyngeal carcinoma.

Adolescent↗
PubMed2001

[Experiences of surgical treatment with cicatricial laryngotracheal atresia: report of 48 cases].

OBJECTIVE: In order to improve the treatment methods of laryngotracheal atresia, several improved surgical procedures were used. METHOD: From 1986, the 48 patients with laryngotracheal atresia accepted surgical treatment in our hospital. Laryngo-fissure with laser cauterization of the glottis, laryngotracheal reconstruction using surgical flaps with or without particles, laryngo-tracheal reconstruction using itself's cicatrices, tracheal end-to-end anastomosis, two-stage laryngotracheal reconstruction using aqueduct method, bronchotracheal reconstruction through the chest. RESULT: 46/48 cases were cured breathing without tracheal cannula. Following-up survey is 1-12 years. CONCLUSION: The treatment of cicatricial laryngotracheal atresia was difficult, but if the surgical methods were selected carefully according to the situation of each patient, we also can get a good result.

Adolescent↗
PubMed2001

[Improvement of a method for separation and determination of amino acids].

A method for separation and determination of amino acids using pre-column derivatization with 6-aminoquinoline-N-hydroxysuccinimido-carbamate (AccQ. Tag) was improved. The technique developed for rapid separation and determination of amino acids by AccQ. Tag method is described. The 18 amino acids and taurine are rapidly separated and determined by AccQ. Tag special chromatographic column(3.9 mm i.d. x 150 mm) within 17.5 min(the analysis period is 22.5 min) by changing the flow rate from 1.0 mL/min to 2.0 mL/min. In place of the AccQ. Tag special chromatographic column, the Nova-Pak C18 column(3.9 mm i.d. x 150 mm), Nova-Pak C18 column(4.6 mm i.d. x 150 mm), Symmetry C18 column(3.9 mm i.d. x 150 mm) or Waters Xterra RP-18 column, can be used to separate and determine the amino acids rapidly in the same manner. But among them the Symmetry C18 column is the best substitute for AccQ. Tag column. The separation time is 14.5 min and the analysis period is 20.0 min only. The price is much cheaper than the AccQ. Tag column.

Amino Acids↗
PubMed2000

Upregulation of Bcl-x and Bfl-1 as a potential mechanism of chemoresistance, which can be overcome by NF-kappaB inhibition.

In A549 human lung adenocarcinoma cells, we found that TNF-alpha and several commonly used chemotherapeutic agents upregulated the expression of Bcl-x and/or Bfl-1/A1 through an NF-kappaB-dependent pathway. While parental A549 cells were resistant to the cytotoxic effects of both TNF-alpha and chemotherapy agents, NF-kappaB-blocked A549 cells were sensitized to both. Expression of either Bcl-x or Bfl-1/A1 in the NF-kappaB-deficient cells at physiological levels provided differential protection against TNF-alpha and chemotherapeutic treatment. These studies provide a potential mechanism for the phenomenon of chemotherapy-induced chemoresistance, and also reveal a potential strategy by which chemoresistance can be overcome.

Adenocarcinoma↗
PubMed2000

Novel purification scheme and functions for a C3-binding protein from Streptococcus pneumoniae.

To isolate microbial proteins capable of binding the third component of complement (C3), we coupled the free sulfhydryl group of methylamine-inactivated C3 to a thiolSepharose matrix. This simple technique facilitated the purification of the first C3-binding protein isolated from a bacterium (Streptococcus pneumoniae). Both metastable (native) and thioester-disrupted C3 were recognized by this protein; binding of C3 was noncovalent, independent of thioester conformation, and preferential for the C3 alpha-chain. Sequencing of amino-terminal and internal peptides from the C3-binding protein disclosed a proline-rich region spanning approximately 20 amino acids and a signal peptide that had not been previously reported. The gene was isolated from a library of genomic DNA from laboratory strain CP1200 by screening with a 1200 bp PCR product amplified from degenerate oligonucleotides encoding the amino terminal sequence and the internal proline-rich sequence. The open reading frame spanned 1692 bp; all peptide sequences were identified in the translated gene product, which also contained at least three choline-binding repeats at the carboxy-terminus. The gene was conserved, and the translated protein was functionally active in pneumococcal clinical isolates of serotypes 1, 3, 4, 14, and 19F. Serum from a patient recovering from acute pneumococcal infection contained IgG antibodies specific for this protein by immunoblot. Wide conservation among clinical isolates, saturable binding of C3, and the ability to stimulate the human immune response have not previously been reported for this choline-binding protein. A similar biochemical approach should enable the identification of other C3-binding proteins in microorganisms able to elude complement-mediated host defense.

Amino Acid Sequence↗
PubMed2000

Plasmodium vivax synonymous substitution frequencies, evolution and population structure deduced from diversity in AMA 1 and MSP 1 genes.

Polymorphic regions of the genes encoding Plasmodium vivax apical membrane antigen 1 (PvAMA1) and P. vivax merozoite surface protein 1 (PvMSP1) were sequenced to examine population diversity both within and between geographical areas. Sequences were obtained for 219 isolates for PvAMA1 and for 175 isolates for PvMSP1 from Africa, China, India, Indonesia, Philippines, Papua New Guinea, Solomon Islands and Thailand. Over half of the isolates were obtained from different regions within the Philippines, and this was used to look at the diversity within a country. Sixty nine haplotypes and 22 polymorphic sites in a 414-bp region of PvAMA1 and 41 haplotypes and 34 polymorphic sites in a 249-bp fragment of PvMSP1 were detected. For both PvAMA1 and PvMSP1, four previously unreported polymorphic nucleotide positions were identified. Population analysis indicated that there were significant differences in allele frequencies between different regions but these differences were small compared to the diversity within populations (Fixation index, F(ST), of 0.126 and 0.078 for PvAMA1 and PvMSP1, respectively). PvAMA1 and PvMSP1 had similar nonsynonymous substitution frequencies but surprisingly, the synonymous substitution frequency for PvMSP1 was eight times the frequency for PvAMA1 suggesting that synonymous substitutions in at least PvAMA1 are not neutral.

Amino Acid Sequence↗
PubMed2000

High level of ferritin light chain mRNA in lens.

Ferritin is of particular interest with regard to cataract because (i) cataract occurs in individuals with hereditary hyperferritinemia cataract syndrome (HHCS), a condition in which ferritin light chain (L-ferritin) protein is overexpressed systemically, and (ii) ferritin is an important regulator of oxidative stress, a primary factor in the etiology of aging-related cataract. From gene array analysis two novel observations were made with respect to ferritin gene expression: first, lenses from guinea pigs and humans have disproportionately high levels of L-ferritin mRNA relative to the amounts of ferritin protein present, and second, L-ferritin message increased markedly in lenses from guinea pigs with hereditary nuclear cataract. The human lens L-ferritin sequence was identical to previous data from human liver; the guinea pig sequence was 86% identical to the human sequence at the amino acid level. Despite mRNA levels similar to those of major lens crystallins, lens ferritin was undetectable by Western blot techniques.

Amino Acid Sequence↗
PubMed2000

A pneumococcal protein that elicits interleukin-8 from pulmonary epithelial cells.

To understand how neutrophils are recruited to the lung in pneumococcal pneumonia, the ability of pneumococcal components to elicit the chemokine interleukin (IL)-8 from monolayers of cultured human type II cells was assessed. Heat-killed clinical and laboratory strains of Streptococcus pneumoniae and secreted proteins from exponentially growing pneumococci elicited significant quantities of IL-8 from A549 cells. All strains that elicited IL-8 production secreted a protein ( approximately 90 kDa) that comigrated on SDS-PAGE with a C3-binding protein previously identified in S. pneumoniae. As little as 7 pmol of the purified 90-kDa protein readily elicited levels of IL-8 production equivalent to those obtained with 1 U of IL-1alpha. Supernatant proteins and heat-killed cells of an isogenic mutant that failed to produce the C3-binding protein elicited significantly less IL-8 than did supernatant proteins or heat-killed cells of the parent strain. These results implicate the C3-binding protein of S. pneumoniae in a novel pathway of pulmonary inflammation.

Bacterial Proteins↗
PubMed2000

Amperometric detection of Escherichia coli heat-labile enterotoxin by redox diacetylenic vesicles on a sol-gel thin-film electrode.

Supramolecular assemblies (bilayer vesicles) prepared from ferrocenic diacetylene lipid and the cell surface receptor ganglioside GM1 are utilized to construct an amperometric biosensor for Escherichia coli heat-labile enterotoxin on a sol-gel thin-film electrode. The bilayer vesicles adsorbed on the sol-gel film provide an open platform for molecular recognition, while the electrochemical communication between the incorporated redox lipids and the electrode is influenced by the binding of the toxin. Cyclic voltammetric studies suggest a facile redox reaction for the adsorbed supramolecular assembly, which allows the sensor to detect enterotoxin up to 3 ppm (3.6 x 10(-8) M) concentration. The apparent diffusion coefficients for the redox lipids in the assembly were observed to be in the range of 4.73 x 10(-8) -2.30 x 10(-8) cm/s2. A mechanism of lateral electron transport of redox lipids controlled by biomolecular recognition is proposed.

Acetylene↗
PubMed2000

Synthesis and biological evaluation of novel 9-functional heterocyclic coupled 7-deoxy-9-dihydropaclitaxel analogue.

Novel 9-functional heterocyclic coupled 7-deoxy-9-dihydropaclitaxel analogues 17 and 22-24 synthesized from a natural taxoid 5-cinnamoyltriacetyltaxicin-I (3) and their biological evaluation in tubulin assembly activity and cytotoxicity in vitro against several human tumor cell lines are first presented. The biologically tested results show that 17, 22 and 23 are inactive in tubulin assembly assay and have no more remarkable cytotoxicities against human tumor cell lines SK-OV3, WIDR and MCF-7, though 22 and 23 exhibit more potent cytotoxicity against human liver cancer and human esophagus cancer cell lines (BEL-7402 and ECa-109) than paclitaxel.

Antineoplastic Agents, Phytogenic↗
PubMed2000

A consensus sequence for long-chain fatty-acid alcohol oxidases from Candida identifies a family of genes involved in lipid omega-oxidation in yeast with homologues in plants and bacteria.

The yeast Candida cloacae is capable of growing on alkanes and fatty acids as sole carbon sources. Transfer of cultures from a glucose medium to one containing oleic acid induced seven proteins of M(r) 102,000, 73,000, 61,000, 54,000, and 46,000 and two in the region of M(r) 45,000 and repressed a protein of M(r) 64,000. The induction of the M(r) 73,000 protein reached a 7-fold maximum 24 h after induction. The protein was confirmed by its enzyme activity to be a long-chain fatty-acid alcohol oxidase (LC-FAO) and purified to homogeneity from microsomes by a rapid procedure involving hydrophobic chromatography. An internal peptide of 30 amino acids was sequenced. A 1100-base pair cDNA fragment containing the LC-FAO peptide coding sequence was used to isolate a single exon genomic clone containing the full-length coding sequence of an LC-FAO (fao1). The fao1 gene product was expressed in Escherichia coli and was translated as a functional long-chain alcohol oxidase, which was present in the membrane fraction. In addition, full-length coding sequences for a Candida tropicalis LC-FAO (faoT) and a second C. cloacae LC-FAO (fao2) were isolated. The DNA sequences obtained had open reading frames of 2094 (fao1), 2091 (fao2), and 2112 (faoT) base pairs. The derived amino acid sequences of fao2 and faoT showed 89.4 and 76.2% similarities to fao1. The fao1 gene is much more highly induced on alkane than is fao2. Although this study describes the first known DNA sequences encoding LC-FAOs from any source, there are unassigned Arabidopsis sequences and an unassigned Mycobacterium sequence in the GenBank(TM) Data Bank that show strong homology to the described LC-FAO sequences. The conservation of sequence between yeast, plants, and bacteria suggests that an as yet undescribed family of long-chain fatty-acid oxidases exists in both eukaryotes and prokaryotes.

Alcohol Oxidoreductases↗
PubMed2000

Epidemiological surveillance of Guillain-Barré syndrome in Sweden, 1996-1997. Network members of the Swedish GBS Epidemiology Study Group.

OBJECTIVES: To set up an epidemiological surveillance system of Guillain-Barré syndrome (GBS) in Sweden and to evaluate the pilot practice of the system for 2 years. MATERIAL AND METHODS: A network of neurologists reported incident patients with a GBS diagnosis among a general population of 4.5 million inhabitants in Sweden during 1996 1997. Historical GBS data from the national hospital in-patient registry were used for predicting incidences and controlling under-reporting. RESULTS: One hundred and seventeen cases were reported. No alarm signals were identified during the study period. A re-analysis of data in 1996 revealed: 1) a higher than expected incidence in the population aged below 40 years in January, and 2) 27% under-reporting mainly associated to one hospital and to GBS patients hospitalized outside neurological departments. Threshold values for GBS incidences among the general and selected populations were obtained from corrected data. CONCLUSION: - The Swedish Network for GBS Surveillance can provide immediate support for epidemiological evaluation of suspected outbreaks or increased GBS incidence.

Adult↗