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Biomedical subjects

Q Chen

Publications and source records attributed to Q Chen.

At least 181 records · Page 10Linked to original sources
PubMed2001

Bioactivation of diclofenac via benzoquinone imine intermediates-identification of urinary mercapturic acid derivatives in rats and humans.

The metabolism of diclofenac has been reported to produce reactive benzoquinone imine intermediates. We describe the identification of mercapturic acid derivatives of diclofenac in rats and humans. Three male Sprague-Dawley rats were administered diclofenac in aqueous solution (pH 7) at 50 mg/kg by intraperitoneal injection, and urine was collected for 24 h. Human urine specimens were obtained, and samples were pooled from 50 individuals. Urine samples were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). Two metabolites with MH(+) ions at m/z 473 were detected in rat urine and identified tentatively as N-acetylcysteine conjugates of monohydroxydiclofenac. Based upon collision-induced fragmentation of the MH(+) ions, accurate mass measurements of product ions, and comparison of LC/MS/MS properties of the metabolites with those of synthetic reference compounds, one metabolite was assigned as 5-hydroxy-4-(N-acetylcystein-S-yl)diclofenac and the other as 4'-hydroxy-3'-(N-acetylcystein-S-yl)diclofenac. The former conjugate also was detected in the pooled human urine sample by multiple reaction-monitoring LC/MS/MS analysis. It is likely that these mercapturic acid derivatives represent degradation products of the corresponding glutathione adducts derived from diclofenac-2,5-quinone imine and 1',4'-quinone imine, respectively. Our data are consistent with previous findings, which suggest that oxidative bioactivation of diclofenac in humans proceeds via benzoquinone imine intermediates.

Acetylcysteine↗
PubMed2001

[Quantitative studies on expression of peripheral blood CD44 and CD54 in non-small cell lung carcinoma].

OBJECTIVE: To assess the relationship between expression of peripheral blood CD44 and CD54 in lymphocyte with non-small cell lung cancer and clinicopathological features. METHODS: Peripheral blood CD44 contents in 50 patients with lung cancer were detected by flow-cytometry, 30 normal donors and 25 patients with benign lesions served as controls. RESULTS: Peripheral blood CD44 and CD54 in lymphocyte with lung cancer were significantly higher than those in benign lesions and normal controls (P < 0.01). There is no distinct difference between CD44 and CD54 in benign lesions and normal controls (P > 0.05). Lung cancer with lymph node metastasis showed higher expression of CD44 and CD54 than lung cancer without lymph node metastasis (P < 0.01). Distinctly statistic difference was showed between CD44 in stage III, IV and stage I, II (P < 0.01). CD54 content in stage IV was higher than that in stage I, II and III, respectively. Histopathological grade was significantly associated with the expression of CD44 and CD54. Peripheral blood CD44 and CD54 contents were not related with squamous cell carcinoma and adenocarcinoma. CONCLUSION: Detection of CD44 and CD54 levels by flow cytometry might be used as a marker to evaluate prognosis and metastasis in patients with non-small cell lung cancer.

Adult↗
PubMed2001

[High-level production of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by feb-batch culture of Alcaligenes eutrophus].

Fermentation strategies for production P (3HB-co-3HV) from glucose and propionic (or valeric) acid by Alcaligenes eutrophus were studied. During the culture, we controlled pH of the broth by feeding precusors of 3HV- propionic or valeric acid after Ammonia feeding stopped. When propionic acid were used as the precusor, for 50 hours, we obtained a cell dry weight, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content and a 3HV fraction of 149.9 g/L, 124.9 g/L, 83.3% and 12.4 mol%, respectively, with a PHA productivity of 2.50 g h-1 L-1. When valeric acid were used as the precusor, for 45 hours, we obtained a cell dry weight, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content and a 3HV fraction of 160.2 g/L, 119.0 g/L, 74.2% and 17.7 mol%, respectively, with a PHA productivity of 2.64 g h-1 L-1. Prior to this study, it hasn't been reported to obtain such high level productivity and 3HV fraction at the same time by Alcaligenes eutrophus.

3-Hydroxybutyric Acid↗
PubMed2001

[Study on psychoprophylaxis and monoamines neurotransmitter of patients with burning mouth syndrome].

OBJECTIVE: Burning mouth syndrome (BMS) is a chronic ache disease, usually occurring in middle aged and old women. This study sought to understand the psychopathologic aspect and monoamines neurotransmitters in the plasma of the patients with BMS. METHODS: Thirty cases were selected (26 females, 4 males); 30 normal control subjects were similar to the BMS cases on age and sex. All subjects were required to complete the Eysenck personality questionnaire (EPQ), and the Self-report Symptom Inventory, Symptom Check List-90 (SCL-90) questionnaire. In case a subject's L (lie) score exceeded 50, she (he) would be removed from the test. 2 ml of blood was drawn from the subject under restine conditions with a fast in the morning to examine norepinephrine and epinephrine contents by high efficient liquid chromatography. Chi-square test, analysis of variance and t'-test were performed. RESULTS: The BMS group had higher scores of nervousness (N) and poikilergasia (P) and lower score of extro/introversion (E) as compared with the control (P < 0.05). The personality types in BMS group were focused on introversion and instability, but in the control group the types were focused on extroversion and stability (P < 0.05). The scores of 9 emotional factors of BMS group were significantly higher than those of the control group (P < 0.05), which indicated that the BMS patients had suffered from serial psychic disorders. The level of plasma norepinephrine in the BMS patients was higher than that of the control (P < 0.01). CONCLUSION: The personality of BMS patients raised body response to harmful stimulations, and obvious psychic disorders in the patient may cause the functional disorders in central and sympathetic nervous systems, which may be associated with BMS' occurrence.

Adult↗
PubMed2001

[Relationship between the symptom of xerostomia and non-stimulated salivary flow rates in patients with burning mouth syndrome].

OBJECTIVE: Many patients with burning mouth syndrome (BMS) complain of xerostomia, but the consistent relationship between the symptom of xerostomia and non-stimulated salivary flow rates remains unclear. This study tried to investigate the variety of non-stimulated salivary flow rates in patients with BMS. METHODS: The non-stimulated salivary flow rates of 52 BMS patients and 37 healthy controls were recorded. RESULTS: The non-stimulated salivary flow rates were low in the group of BMS patients, but there is no statistical difference when compared with that of the normal individuals. There was also no significant difference in non-stimulated salivary flow rates among theses three subtypes of BMS patients. Further, no significant difference of non-stimulated salivary flow rates was observed in patients with and without xerostomia. CONCLUSION: The non-stimulated salivary flow rate may be not associated with the symptom of xerostomia in patients with BMS.

Burning Mouth Syndrome↗
PubMed2001

[Phospholipase activities of Candida albicans isolates from oral pre-malignant lesions and oral cancers].

OBJECTIVE: The aim of this study is to compare activities of phospholipase of Candida albicans isolates from oral cavities of two groups of patients, including oral pre-malignant lesions and oral cancers. METHODS: A total of 55 isolates, including oral pre-malignant lesions (21), oral cancers (15), and normal health control (19), were studied using the precipitate zone assay on the egg yolk agar. RESULTS: No significant difference was found in phospholipase activities between these isolates from normal controls and oral pre-malignant lesions, while the activities of phospholipase of isolates from oral cancers were higher than those of the normal controls. CONCLUSION: Candida albicans may play different roles in different manners in these two closely related diseases.

Candida albicans↗
PubMed2001

[Research on the immunological cause of auricular pseudocyst].

OBJECTIVE: To elucidate the relationship between the auricular pseudocyst and the immunological function of patients. METHOD: The cyst fluid and blood sample had been detected for contents of IgG, IgA, IgM and complement C3 by radial immunodiffusion, immunocomplex (IC) contents by polyethylene glycol turbidimetry in 55 cases, anti-nuclear antibody (ANA) by immuno-fluorescent technique in 23 cases, extractable nuclear antibody (ENA) by immunotransfer technique in 24 cases. The frozen sections of cyst wall tissue of 24 cases had been detected for immunocomplex by immunoenzyme histochemistric method. The reactions were observed separately between the auricle tissue of healthy white rat, human embryo and cyst fluid, serum of patient and normal serum. RESULT: Contents of IgG, IgA, IgM and C3 in the cyst fluid were lower than the serum significantly (P < 0.01). No IC, ANA and ENA could been found both in serum and cyst fluid, but reactive immunocomplex was discovered on the auricle cartilagous tissue of patient, immunocomplex also be observed on human embryo aurical tissue when it reacted with cyst fluid, but complex hadn't be found when the auricle tissue of white rat and human embryo reacted with serum of patient and normal people. CONCLUSION: The reason of auricular pseudocyst may be related with the local autoimmune status of patient.

Adult↗
PubMed2001

[Cloning and expression of the envelope glycoprotein gD gene of pseudorabies virus EA strain].

The envelope glycoprotein gD gene of pseudorabies virus Ea strain was cloned via PCR technique. Sequence analysis displayed 98% nucleotide sequence homology and 97% deduced amino acid sequence homology between our cloned gD gene and PRV Rice strain gD gene. The recombinant transfer plasmid pSX35A-gD was obtained by inserting D gene into the baculovirus transfer vector pSX35A with whole-phase promoter cassette, then transfected insect cell Hi5 with linearized AcMNPV-OCC- virus DNA, and formed recombinant baculoviruses AcMNPV-OCC(+)-gD by homologous recombination in insect cell. Recombinant baculoviruses infected insect cell Hi5 after being purified by plaque assay. Both SDS-PAGE and Western-blotting showed glycoprotein gD with a molecular weight of about 47 kD was expressed specifically, product was about 6.2% of total cellular protein, and expressed gD was of immunogenicity.

Animals↗
PubMed2001

[Diversity of metabolites and their bio-activities in myxobacterium Sorangium cellulosum].

Different Sorangium cellulosum strains not only showed diversity in their cell and fruiting body morphologies, but also differences of bio-activities and components of the metabolites. All the Sorangial strains studied in this paper had no activity on Gram-negative bacteria, some were able to repress Gram-positive bacteria. However, all the strains were able to repress growth of fungi and tumor cells strongly and widely. Thin layer chromatography assay of metabolites showed multi-components in the metabolites, and most of them have abilities of repressing fungi and tumor cells in different degrees. Four strains were found to be able to produce compounds with activity of promoting polymerization of microtubule. Based on Rf value on TLC, the bio-active component produced by So33-1 strain was similar to Epothilone A, while that of So81 was much different. The results of this paper suggested that Sorangium cellulosum is a much beneficial resource for screening nature compounds with bio-activities against eukaryotes.

Antineoplastic Agents↗
PubMed2001

[Comparative analysis on the hearing ability of children in iodine deficiency areas born before and after iodine supplementation].

UNLABELLED: According to the detection of hearings ability of children in iodine deficiency areas who was born before and after iodine supplement, the effects of iodine supplement on hearing system development was evaluated. METHOD: Hearing was tested by AS-72 type pure zone diagnostic audiometer(made in Denmark). Hearing of 11-14 years old students were tested before iodine supplement in iodine deficiency areas in 1984, the control was students living in non-iodine deficiency areas. Iodine salt (50 mg/kg) were supplied by the end of 1984, the hearings of children born after one year of iodine supplied were tested in 1999. The result showed that the average hearing threshold of students before iodine supplied in iodine deficiency areas was significance higher than of non-iodine deficiency areas. The hearing of children born after one year of iodine salt supplied in deficient areas had no significant difference from that of normal areas. The development of hearing system might be deteriorated by iodine deficiency during pregnant. It was able to meet the need of iodine that pregnant women ate 1:20 thousands iodine salt.

Child↗
PubMed2001

[Isolation and identification of steroidal saponins from Dioscorea panthaica Prain et Burkill].

AIM: To investigate the chemical constituents of the rhizomes of Dioscorea panthaica Prain et Burkill and look for new active compounds. METHODS: The compounds were isolated with silica gel and HPLC, and their structures were elucidated on the basis of chemical evidences and spectral analysis (IR, ESI-MS, 1HNMR, 13CNMR, DEPT, 1H-1H COSY, HMQC, HMBC, NOESY). RESULTS: Three steroidal saponins were isolated from the rhizomes of Dioscorea panthaica. They were elucidated as 26-O-beta-D-glucopyranosyl-3 beta, 26-diol-23(S)-methoxy-25(R)-delta 5,20(22)-diene-furosta-3-O-[alpha-L-rhamnopyranosyl-(1-->2)- O-alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside (I), pseudoprotodioscin (II), 26-O-beta-D-glucopyranosyl-3 beta, 26-diol-25 (R)-delta 5,20(22)-diene-furosta-3-O-alpha-L-rhamnopyranosyl- (1-->2)-O-beta-D-glucopyranoside (III). CONCLUSION: Compound I is a new steroidal saponin and was named as dioscoreside C. Compound II and III were obtained from this genus for the first time.

Dioscorea↗
PubMed2001

[Effects of intracerebroventricular administration of endomorphin-1 on blood pressure in anesthetized rats].

AIM: To observe the effects of intracerebroventricular administration of endomorphin-1 on blood pressure in anesthetized rats and to assess its mechanism. METHODS: Variations of mean arterial pressure (MAP) were observed after icv injection of endomorphine-1 in rats. The effects of i.v. or icv of various blockers, naloxone, phentolamine, propranolol, atropine and N omega-nitro-L-arginine, on the variation of MAP caused by endomorphin-1 were observed. RESULTS: Endomorphin-1 was shown to decrease MAP. The decrease in MAP was blocked by naloxone. Pretreatments with icv phentolamine and propranolol showed no effect on the vasodepression induced by icv endomorphin-1. However, pretreatment with icv atropine (25 micrograms.kg-1) attenuated the vasodepression. Pretreatments with i.v. phentolamine, propranolol and N omega-nitro-L-arginine showed no effect on the vasodepression induced by icv endomorphin-1. But, pretreatment with i.v. atropine (50 micrograms.kg-1) and bilateral vagotomy attenuated the vasodepression. CONCLUSION: Intracerebroventricular administration of endomorphin-1 produces vasodepressor response in anesthetized rats, which is mediated by opioid receptor. The vasodepression is associated with the central M cholinoceptor and the excitation of the vagus.

Anesthesia↗
PubMed2001

[Effects of endomorphins and their analogs on cardiovascular system].

AIM: To analyze the effects of endomorphins (EMs) and their analogs ([D-Pro2]EM-1, [D-Ala2]EM-1, [D-Pro2]EM-2 and [D-Ala2]EM-2) on the cardiovascular system of anestetized rats and to study its mechanism. METHODS: Responses to EMs and their analogs were investigated in the systemic vascular bed of rats and the mesenteric microarteria of Bufo gargarizans. Responses to EMs were investigated on the hindquarters of the rat vascular bed under constant-flow conditions and on the isolated rabbit thoracic aorta strips. RESULTS: The EMs and their analogs showed dose-related (10(-9)-10(-6) mol.L-1, i.v.) and naloxone-sensitive (2 mg.kg-1, i.v.) hypotension in mean arterial pressure of rats with similar duration and vasodilatation in mesenteric microarteria of Bufa gargarizans. The sequence of potencies was EMs > [D-Pro2] EM-2 > [D-Ala2]EM-2 > [D-Ala2]EM-1 > [D-Pro2]EM-1. EMs were shown not to relax the isolated rabbit thoracic aorta strips without endothelium. EMs, however, relaxed them with endothelium significantly. This action was blocked by Nx (10(-5) mol.L-1) and L-NNA (10(-4) mol.L-1). CONCLUSION: The significant hypotensive activity of EMs and their analogs is mainly associated with their vasodilatation, which is related to the release of NO from vascular endothelium, and their potency is not completely related to their affinity for mu-opiate receptor.

Animals↗
PubMed2001

[Evaluation of sensorineural hearing loss in childhood].

OBJECTIVE: To explore the clinical and audiological characteristics of sensorineural hearing loss (SHL) with pathological changes both in cochlea and retrocochlear in children and evaluate the relationship between SHL and the lesions in the central nervous system (CNS). METHODS: Three hundred and ten cases (500 ears) of SHL accepted between 1998 and 2000 were studied. The age of patients was ranged from 1 month to 6 years old. According to the evaluation of function of CNS by pediatric neurologist, all cases were divided into two groups: SHL with CNS disease and SHL without CNS disease. Some same age children without hearing loss were subjected as control group. All children were tested using both auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE). RESULTS: 1. The rate of SHL accompanied with CNS diseases was very high in these children. 2. Patients with kernicterus-cerebral palsy usually had serious hearing loss caused by acoustic nerve lesion at retrocochlear, but their cochlea function was injured slightly. Patients with external hydrocephalus had only slight acoustic nerve lesion at retrocochlear, and patients with other CNS diseases usually had no change for their cochlea function. 3. In the group of SHL caused by cochlea lesion, amplitudes of DPOAE decreased obviously when the threshold of wave V of ABR was up to 60 dB nHL, and amplitudes of DPOAE seriously decreased or disappeared when the threshold of wave V was up to above 70 dB nHL. CONCLUSION: The patients with SHL are usually accompanied with CNS diseases in childhood, and their hearing loss appears very difference from audiological characteristics. We suggest that it is necessary to test both ABR and DPOAE in these patients, and it is important that pediatric neurologist join in audiologist team for our clinical study.

Brain Edema↗
PubMed2001

The pathogenesis of experimental model of mitochondrial myopathy induced by germanium dioxide.

OBJECTIVE: The purpose of the study was to build up an animal model of mitochondrial myopathy in order to analyse the pathogenesis of the disease. METHODS: The skeletal muscles from Wistar rats treated with germanium dioxide for 24 weeks were analysed by histopathologic and electron-microscopic studies. A quantitative analysis was carried out in mitochondrial DNAs of these samples. The biological function of the model was determined. RESULTS: An animal model of mitochondrial myopathy was built up, in which oxygen free radicals were increased and mitochondrial DNA copies were decreased contrasted with controls. CONCLUSION: It suggested that environmental toxin may play a role in the pathogenesis of mitochondrial myopathy. The increase of oxygen free radicals is an important link causing the disease.

Animals↗
PubMed2001

[A clinical investigation into the effect of comfort denture adhesive on masticatory function with complete dentures].

OBJECTIVE: The purpose of this study was to evaluate the clinical effect of the new developed form of Comfort denture adhesive (Comfort DA). METHODS: 10 edentulous patients with complete dentures were selected for this study. The maximum biting force and masticatory efficiency were recorded before and after application of the adhesive to all the new and old dentures. Subjective test was also used to evaluate this adhesive in enhancing retention and stability of complete denture using the questionnaire way. RESULTS: The data indicated that significantly greater biting forces were generated with old dentures than with the new dentures. The major findings were that the adhesive produced a statistically significant improvement in the masticatory efficiency after application. Subjective views of the patients indicated that this tested product significantly improved denture retention, stability and had other favorable features. The time of adhesion was about 6 8 hours. CONCLUSION: The generally favorable clinical performance of the developed Comfort DA formulation indicated that it might be an efficacious denture adhesive.

English Abstract↗
PubMed2000

Mitogen-activated protein kinase p38 mediates regulation of chondrocyte differentiation by parathyroid hormone.

Parathyroid hormone (PTH) and its related peptide regulate endochondral ossification by inhibiting chondrocyte differentiation toward hypertrophy. However, the intracellular pathway for transducing PTH/PTH-related peptide signals in chondrocytes remains unclear. Here, we show that this pathway is mediated by mitogen-activated protein kinase (MAPK) p38. Incubation of hypertrophic chondrocytes with PTH (1-34) induces an inhibition of p38 kinase activity in a time- and dose-dependent manner. Inhibition of protein kinase C prevents PTH-induced p38 MAPK inhibition, whereas inhibition of protein kinase A has no effect. Thus, protein kinase C, but not protein kinase A, is required for the inhibition of p38 MAPK by PTH. Treatment of hypertrophic chondrocytes by PTH or by p38 MAPK inhibitor SB203580 up-regulates Bcl-2, suggesting that Bcl-2 lies downstream of p38 MAPK in the PTH signaling pathway. Inhibition of p38 MAPK in hypertrophic chondrocytes by either PTH, SB303580, or both together leads to a decrease of hypertrophic marker type X collagen mRNA and an increase of the expression of prehypertrophic marker cartilage matrix protein. Therefore, inhibition of p38 converts a hypertrophic cell phenotype to a prehypertrophic one, thereby preventing precocious chondrocyte hypertrophy. Taken together, these data suggest a major role for p38 MAPK in transmitting PTH signals to regulate chondrocyte differentiation.

Animals↗