Biomedical subjects

Q Zeng

Publications and source records attributed to Q Zeng.

At least 73 records · Page 4Linked to original sources

PubMed2000

Determination of intermediate biomarker expression levels by quantitative reverse transcription-polymerase chain reaction in oral mucosa of cancer patients treated with liarozole.

Liarozole is a 1-substituted imidazole derivative that inhibits cytochrome P450 activity and increases endogenous plasma concentrations of retinoid acid (RA). We have previously demonstrated that RA down-modulates transforming growth factor (TGF)-alpha and epidermal growth factor receptor (EGFR) levels in head and neck squamous cell carcinoma by decreasing the transcription rate of these two genes. Previous reports suggest that RA receptor (RAR)-beta levels are down-modulated in head and neck cancer and are restored by RA therapy. Cellular RA-binding protein (CRABP)-II is up-regulated by RA and appears to modulate intracellular RA metabolism. In conjunction with a Phase I clinical trial, total intact RNA was extracted from oral cavity mucosa biopsied from 17 patients with advanced malignancies, before and after treatment with a 4-week course of liarozole. To analyze these limited quantities of total RNA (as little as 0.6 microg/sample), a quantitative reverse transcription-PCR assay was developed using delayed dropping of the 5' beta-actin primer to amplify the highly abundant beta-actin gene as an internal control. We used this method to determine the expression levels of TGF-alpha, EGFR, RAR-beta, and CRABP-II before and after treatment. There was a trend toward elevation of RAR-beta levels in oral mucosa after liarozole therapy (P = 0.107), whereas TGF-alpha, EGFR, and CRABP-II were not modulated by systemic liarozole treatment. These results suggest that liarozole may up-regulate RAR-beta in tissues from cancer patients and that expression levels of potential intermediate biomarkers may be determined in small tissue biopsies using a quantitative reverse transcription-PCR assay.

Actins↗

PubMed2000

GLIF3: the evolution of a guideline representation format.

The Guideline Interchange Format (GLIF) is a language for structured representation of guidelines. It was developed to facilitate sharing clinical guidelines. GLIF version 2 enabled modeling a guideline as a flowchart of structured steps, representing clinical actions and decisions. However, the attributes of structured constructs were defined as text strings that could not be parsed, and such guidelines could not be used for computer-based execution that requires automatic inference. GLIF3 is a new version of GLIF designed to support computer-based execution. GLIF3 builds upon the framework set by GLIF2 but augments it by introducing several new constructs and extending GLIF2 constructs to allow a more formal definition of decision criteria, action specifications and patient data. GLIF3 enables guideline encoding at three levels: a conceptual flowchart, a computable specification that can be verified for logical consistency and completeness, and an implementable specification that can be incorporated into particular institutional information systems.

Decision Support Techniques↗

PubMed2000

[The effect of tetrahydropalmatine on ouabain-induced delayed after depolarization and triggered ventricular arrhythmia].

OBJECTIVE: To study the effect and mechanism of tetrahydropalmatine (THP) ouabain-induced on delayed after depolarization (DAD) and anti-triggered ventricular arrhythmia in in-vivo rabbit heart. METHODS: 14 rabbits were divided into two groups at random, control group and THP group. The monophasic action potential (MAP) of right ventricule and the surface lead II electrocardiogram (ECG) were simultaneously recorded. The changes of MAP and ECG in the THP group were compared with those in the control group after administration of ouabain 150-170 ug/kg and before using the drug. RESULTS: The incidence and couple interval of DAD in the two groups had no apparent difference (P > 0.05) after administration of ouabain, but the amplitude of DAD and the incidence of triggered ventricular arrhythmia in the THP group were significantly lower than those in the control group (P < 0.05). CONCLUSION: THP had the effect of decreasing the amplitude of DAD of rabbit heart induced by ouabain thus reducing the chance of triggered ventricular arrhythmia induced by DAD.

Action Potentials↗

PubMed2000

[Clinical application of magnetic resonance angiography in the body].

OBJECTIVE: To identify the accuracy and reliability of magnetic resonance angiography (MRA) in evaluating patients with vascular lesions in the body. METHODS: 171 patients with suspected vascular lesions in the body were examined by MRA and compared with the results of X-ray angiography (XRA) or operation. RESULTS: MRA showed abnormal vein in 12 patients and normal in 6 corresponding to XRA or operation. MRA revealed aneurysm in 54 patients: aortic dissection (26), aortic aneurysm (15) and peripheral aneurysm (13). Two peripheral aneurysms could not only be found by MRA. The sensitivity of MRA was 97% for aneurysm lesions. The sensitivity of MRA in the diagnosis of suspicious peripheral artery stenosis in 84 patients was 95%, the specificity 89%, and the accuracy 92% in comparison with those of XRA and operation. CONCLUSION: MRA is accurate and reliable in evaluating vascular lesion in the body and can replace XRA in many cases.

Adolescent↗

PubMed2000

[Experimental study of protective effect of qingkailing on glutamate induced neurotoxic damage of brain].

OBJECTIVE: To observe the effect of Qingkailing (QKL) on glutamate induced damage of brain, in order to seek for effective drugs for antagonizing neurotoxicity of glutamate. METHODS: Number and morphology metrology of neuron in cerebral cortex and hippocampus were detected by using MIAS-300 image analysing instrument, electron microscope and immunohistochemical methods. RESULTS: QKL could allevate the glutamate induced accumulation of water and sodium in the brain tissue, relief the damage of cerebral cells and reduce the percentage of c-fos positive cell in brain. CONCLUSION: QKL could protect brain damage induced by glutamate, which might be related to inhibition of QKL on glutamate caused enhancement of c-fos gene expression.

Animals↗

PubMed1999

p53 and Bax: putative death factors in taste cell turnover.

The turnover of cells in renewing epithelia presents an opportunity to examine cell death pathways in adult vertebrates. In mouse lingual epithelium a typical taste receptor cell survives for 9 days, until it is killed by an unknown cascade of death factors. Apoptosis was implicated by the presence of fragmented DNA in about 8% of taste receptor cells in the vallate papilla. In using immunocytochemistry to seek putative death factors, we observed that squamous epithelial cells of the tongue were negative for Bax, a death factor in the Bcl-2 family of survival/death factors, and were also negative for p53, a tumor-suppressor protein linked to apoptosis and Bax transcription. In contrast, 8-10% of the taste receptor cells were Bax-positive, and 9-11% were p53 positive. These immunopositive taste receptor cells were more likely to display death-related morphologic defects than other receptor cells, and they frequently coexpressed p53 and Bax. In both neonatal and adult mice, the labeling of dividing cells with 5-bromo-2'-deoxyuridine indicated that all Bax-positive taste cells were at least 5 days old. On postnatal day 7, when few taste cells were old, no more than 1% of taste cells were immunopositive for either p53 or Bax. We inferred that old taste receptor cells employ p53 and Bax as part of their apoptotic death pathway. The routine expression of p53 by postmitotic, aged taste cells broadens the conventional view that p53 is restricted to mitotic cells that have stress-damaged DNA. Furthermore, the scattered distribution of aged receptor cells within the taste bud excludes some explanations for stable taste signals during receptor cell turnover.

Aging↗

PubMed1999

Structural insight into a quinolone-topoisomerase II-DNA complex. Further evidence for a 2:2 quinobenzoxazine-mg2+ self-assembly model formed in the presence of topoisomerase ii.

Quinobenzoxazine A-62176, developed from the antibacterial fluoroquinolones, is active in vitro and in vivo against murine and human tumors. It has been previously claimed that A-62176 is a catalytic inhibitor of mammalian topoisomerase II that does not stabilize the cleaved complex. However, at low drug concentrations and pH 6-7, we have found that A-62176 can enhance the formation of the cleaved complex at certain sites. Using a photocleavage assay, mismatched sequences, and competition experiments between psorospermin and A-62176, we pinpointed the drug binding site on the DNA base pairs between positions +1 and +2 relative to the cleaved phosphodiester bonds. A 2:2 quinobenzoxazine-Mg2+ self-assembly model was previously proposed, in which one drug molecule intercalates into the DNA helix and the second drug molecule is externally bound, held to the first molecule and DNA by two Mg2+ bridges. The results of competition experiments between psorospermin and A-62176, as well as between psorospermin and A-62176 and norfloxacin, are consistent with this model and provide the first evidence that this 2:2 quinobenzoxazine-Mg2+ complex is assembled in the presence of topoisomerase II. These results also have parallel implications for the mode of binding of the quinolone antibiotics to the bacterial gyrase-DNA complex.

Antineoplastic Agents↗

PubMed1999

Contribution of melanocortin receptor exoloops to Agouti-related protein binding.

Agouti-related protein (AGRP) is an endogenous antagonist of melanocortin action that functions in the hypothalamic control of feeding behavior. Although previous studies have shown that AGRP binds three of the five known subtypes of melanocortin receptor, the receptor domains participating in binding and the molecular interactions involved are presently unknown. The present studies were designed to examine the contribution of extracytoplasmic domains of the melanocortin-4 receptor (MC4R) to AGRP binding by making chimerical receptor constructs of the human melanocortin-1 receptor (MC1R; a receptor that is not inhibited by AGRP) and the human MC4R (a receptor that is potently inhibited by AGRP). Substitutions of the extracytoplasmic NH2 terminus and the first extracytoplasmic loop (exoloop) of the MC4R with homologous domains of the MC1R had no effect on AGRP (87-132) binding affinity or inhibitory activity (the ability to inhibit melanocortin-stimulated cAMP generation). In contrast, cassette substitutions of exoloops 2 and 3 of the MC4R with the homologous exoloops of the MC1R resulted in a substantial loss of AGRP binding affinity and inhibitory activity. Conversely, the exchange of exoloops 2 and 3 of the MC1R with the homologous exoloops of the MC4R was found to confer AGRP binding and inhibitory activity to the basic structure of the MC1R. Importantly, these substitutions did not affect the ability of the alpha-melanocyte stimulating hormone analogue [Nle4,D-Phe7] melanocyte stimulating hormone to bind or activate the chimeric receptors. These data indicate that exoloops 2 and 3 of the melanocortin receptors are important for AGRP binding.

Agouti-Related Protein↗

PubMed1999

Sequence analysis of Pasteurella multocida major outer membrane protein (OmpH) and application of synthetic peptides in vaccination of chickens against homologous strain challenge.

Pasteurella multocida major outer membrane protein (OmpH) has been previously characterized as a porin. The native OmpH from strain X-73 (serotype 1) but not recombinant protein from Escherichia coli induced homologous protection in chickens. In this study OmpH sequences from 15 P. multocida serotypes as well as the CU vaccine strain were compared by sequence alignment and revealed high homology, with major variations confined to two discrete regions which were correspondingly predicted as two largest external loops. Secondary structures of OmpHs were predicted by sequence alignment of OmpHs with well defined porins and analyses of amphiphilicity, hydrophobic moment and antigenic index plots. Several synthetic peptides derived from predicted loop 2 and loop 5 of X-73 OmpH were synthesized as vaccine candidates. Vaccination studies in chickens showed that the cyclic synthetic peptide (Cyclic-L2) mimicking the predicted loop 2 induced 70% protection in chickens against strain X-73 challenge. This is the first report that a synthetic peptide mimicking the conformational epitopes of a native protein provide practical protection in target animal against bacterial infection.

Amino Acid Sequence↗

PubMed1999

The safety profile, tolerability, and effective dose range of rofecoxib in the treatment of rheumatoid arthritis. Phase II Rofecoxib Rheumatoid Arthritis Study Group.

Nonsteroidal anti-inflammatory drugs. (NSAIDs) inhibit both cyclooxygenase (COX)-1 and COX-2 isoenzymes and are effective in the treatment of inflammatory disorders. This 8-week, double-masked, placebo-controlled trial was undertaken to assess the safety profile, tolerability, and effective dose range of once-daily rofecoxib, a COX-2-specific inhibitor, in the treatment of rheumatoid arthritis (RA). After a 3- to 15-day washout of prior NSAID therapy, 658 patients were randomly allocated to receive placebo or rofecoxib 5 mg, 25 mg, or 50 mg once daily. Safety profile, tolerability, and efficacy were evaluated after 2, 4, and 8 weeks of therapy. Six hundred fifty-eight patients (168, 158, 171, and 161 in the placebo and 5-mg, 25-mg, and 50-mg rofecoxib groups, respectively) were enrolled at 79 clinical centers in the United States. Mean age was 55 years, mean duration of RA was 10 years, and 506 (77%) of the 658 patients were female. All groups had similar baseline demographic characteristics. Patients taking rofecoxib 25 and 50 mg showed significant clinical improvement compared with those taking placebo; 43.9% in the rofecoxib 25-mg group and 49.7% in the rofecoxib 50-mg group completed the treatment period and achieved an American College of Rheumatology 20 response (P = 0.025 and 0.001 vs. placebo, respectively). The 5-mg dose of rofecoxib did not differ significantly from placebo. Patients in the rofecoxib 25- and 50-mg groups showed significant improvement in key individual efficacy measurements, including patient global assessment of pain, patient and investigator global assessment of disease activity, and Stanford Health Assessment Questionnaire Disability Index (P<0.05 vs placebo). Compared with placebo, significantly fewer patients in the 25-mg and 50-mg rofecoxib groups discontinued therapy because of lack of efficacy (P = 0.02 and P = 0.032, respectively). Our results show that rofecoxib 25 and 50 mg once daily was effective and generally well-tolerated in patients with RA.

Adult↗

PubMed1999

Intrathecal gadolinium-enhanced MR myelography and cisternography: a pilot study in human patients.

OBJECTIVE: This study was designed to evaluate the safety, MR imaging characteristics, and clinical response to intrathecal gadopentetate dimeglumine (gadolinium) administration in human patients. SUBJECTS AND METHODS: Eleven adult patients were included in this prospective study. Via lumbar puncture, a single dose of either 0.2 ml, 0.5 ml, or 1.0 ml of gadolinium (500 mmol/l) mixed with 5 ml of previously removed CSF was slowly injected into the lumbar subarachnoid space. Immediate and delayed MR imaging were subsequently carried out using a 1.0-T magnet. RESULTS: No patient manifested gross behavioral changes, neurologic alterations, or seizure activity. The intrathecal gadolinium-enhanced MR myelography revealed disk herniation (n = 4), posttraumatic spinal stenosis (n = 3), postsurgical noncommunicating cyst (n = 1), myelitis (n = 1), intradural extramedullary mass formation (n = 1), and intradural vascular malformation (n = 1). CONCLUSION: This pilot study shows the relative safety and feasibility of low-dose intrathecal gadolinium administration. The potential clinical applications include the evaluation of obstructions and communications of the subarachnoid space, spontaneous or traumatic CSF leaks, and CSF dynamics. Additional animal and human studies must be performed to further evaluate the long-term safety and to prove the clinical applications of this procedure in a larger number of subjects.

Adult↗

PubMed1999

Effect of specific COX-2 inhibition in osteoarthritis of the knee: a 6 week double blind, placebo controlled pilot study of rofecoxib. Rofecoxib Osteoarthritis Pilot Study Group.

OBJECTIVE: To determine the efficacy and safety of the cyclooxygenase 2 (COX-2) specific inhibitor, rofecoxib in patients with osteoarthritis (OA) of the knee. METHODS: Rofecoxib, 25 mg or 125 mg once daily, was compared with placebo in a 6 week, double blind, parallel group, randomized, multicenter study of 219 patients with knee OA. RESULTS: Both doses of rofecoxib produced clinically significant improvement as assessed by primary (e.g., WOMAC Pain Subscale 0-100 mm, decrease from baseline: placebo: 7.1 mm; rofecoxib 25 mg: 28.1 mm, rofecoxib 125 mg: 28.0 mm; p < 0.001 rofecoxib vs placebo) and secondary efficacy (p < 0.05) criteria compared with placebo. Clinical improvement with the 25 mg dose was similar to that with the 125 mg dose. Both rofecoxib doses were generally well tolerated. CONCLUSION: Specific inhibition of COX-2 by 25 and 125 mg rofecoxib, administered once daily, resulted in clinically meaningful improvements in patients with OA. This study confirms that COX-2 derived prostanoids are important clinical mediators of pain and other symptoms of knee OA and that inhibition of COX-1 is not required to provide clinical benefit.

Adult↗

PubMed1999

Evaluation of a system to identify relevant patient information and its impact on clinical information retrieval.

Concept-oriented views of electronic medical records are desirable, yet difficult to create. We have developed a system that creates concept-oriented views by identifying relevant patient information, however, previous such systems have received little evaluation. We present here an evaluation of our system's ability to identify relevant patient data and generate concept-oriented views, along with the clinical impact of the generated views. The evaluation was carried out in three parts: First, using physicians and medical literature as gold standards, the system's sensitivity and specificity in identifying relevant information were measured. In some areas, the system demonstrated sensitivity comparable to that of physicians. Second, concept-oriented views were compared with original records and shown to contain significantly less non-specific information. Third, physician volunteers, when answering questions about patient cases using the concept-oriented views and traditional source-oriented views generated by the system, showed a significantly greater accuracy in information retrieval using concept-oriented views.

Clinical Laboratory Techniques↗

PubMed1999

[The permeability of the cell membrane in the human uterine smooth muscle at term pregnancy].

OBJECTIVE: To study the changes of the permeability of the uterine smooth muscle cell membrane at the various stages of labor, and comparing with the onset of labor. METHODS: 18 women (38 to 41 gestational weeks) were divided into three groups: late pregnancy not in labor, prelabor, active labor, and six cases in each group. The myometrium tissues in the corpus and lower segment of the uterus were studied by the Lanthanum tracing method under transmission electron microscopy (TEM). RESULTS: Lanthanum entered into the smooth muscle cells, deposited in the mitochondria. The positive rates of the smooth muscle cells of lower segment by lanthanum tracing were markedly higher than that of corpus in late pregnancy group (P < 0.05), the difference were not found between lower segment and corpus in prelabor group (P > 0.05). The positive rates in corpus were significant higher than that of lower site in the active labor group (P < 0.05); Comparing corpus to corpus, the positive rates were not significantly different between late pregnancy and prelabor group (P > 0.05), then in active labor group it were markedly higher than those in the other two groups (P < 0.05, respectively); but in lower segment, the positive rates in late pregnancy group were significant higher than that in prelabor and active labor group (P < 0.05 respectively), no difference was found between prelabor and active labor (P > 0.05). The lanthanum deposition in the late pregnancy and prelabor groups was mainly showed in larger mitochondria within the smooth muscle cell while in active labor group, it laid on the outer and inner membrane and cristae of all the mitochondria. CONCLUSION: The permeability of uterine smooth muscle cell membrane at term, pregnancy increases, especiany in uterine corpus, which showed a close correlation with the onset of labor.

Adult↗

PubMed1999

[Ankylosing spondylitis in Shantou: clinical experience in fifteen years].

OBJECTIVE: To evaluate the clinical features of ankylosing spondylitis (AS) in Shantou area and improve the diagnostic level and therapeutic effect. METHODS: Clinical and laboratory data, and the methods and effects of therapy were analyzed. Some patients were followed up. RESULTS: 94% of the cases had an insidious onset. Low back pain or discomfort, peripheral arthritis, positive "4" test and pressing tenderness over the sacroiliac joints and lumbar spine were the frequent symptoms and signs. The degree of sacroiliitis and involvement of hip and spine were related to the disease duration. However, hip joint involvement in juvenile onset AS did not relate to the disease duration. Some cases with disease duration as long as 16 years still remained at II of degree sacroiliitis. Clinical improvement was more obvious in the first two years of treatment. Although some patients came to a standstill condition after this period, yet the disease activity might still relapse with withdrawal of the treatment. The rate of adhering to the treatment for 1, 2, and over 5 years was 34.6%, 28.4%, and 10.3% respectively. The radiological changes frequently did not parallel with the clinical manifestations. CONCLUSION: Early diagnosis is of importance in improving the prognosis of AS and adherence to slow-acting anti-rheumatic drug therapy is beneficial in disease controlling. A follow up of more than 3 years is necessary to estimate the therapeutic efficacy, and the radiological change is the key indicator. AS is a heterogenic disease and the risk factors for prognosis should be further studied.

Adolescent↗

PubMed1999

[A study of expression of p53, c-myc and PCNA in retinoblastoma].

OBJECTIVE: To investigate the expressions of p53, c-myc (oncogene) and proliferating cell nuclear antigen (PCNA) in retinoblastoma (Rb) and the relationships of the expression to the degree of differentiation and optic nerve infiltration. METHOD: The expressions of p53, c-myc and PCNA in Rb tissues of 31 cases were analyzed by using LSAB immunohistochemical method. RESULTS: The positive rates of p53, c-myc and PCNA in Rb were respectively 51.6%, 45.2% and 67.7% and all the expressions were significantly related to the differentiation degree of Rb (all P < 0.05). The expression of PCNA was significantly related to the optic nerve infiltration of Rb (P < 0.05). Both the expressions of p53 and c-myc in Rb were markedly correlated with the expression of PCNA (all P < 0.05). CONCLUSIONS: The occurrence of Rb is the result of multiple gene mutations. The determinations of p53, c-myc and PCNA are of significance for evaluating the histologic characteristics and biological behavior of Rb.

Child, Preschool↗

PubMed1999

[The effects of transforming growth factor alpha and beta 1 on the proliferation of alveolar type II cells in vitro].

OBJECTIVE: To investigate the effect of transforming growth factor alpha and beta(1) (TGFalpha and beta(1)) on the proliferation of alveolar type II cells in vitro and the molecular mechanism related. METHODS: (3)H-TdR incorporation and cell counting for the assay of cell growth; dot blot, in situ hybridization, and immunohistochemical methods for analysing the expression of cyclin D1 and cycle-dependent kinase 4 (CDK4) genes. RESULTS: With increasing of the concentration of TGFalpha and beta(1) (0.01 ng-100 ng/ml), TGFalpha enabled to increase (3)H-TdR incorporation and the number of alveolar type II cells, while the effect of TGFbeta(1) was opposite and both effects were dose-dependent (P < 0.01). TGFalpha-treated cells decreased the expression of CDK4 mRNA, and the relevant in comparing with the control (P < 0.01). On the contrary, TGFbeta(1)-treated cells decreased the expression of CDK4 mRNA), CDK4 as well as the cyclin D1 proteins (P < 0.05). CONCLUSION: Both TGFalpha and beta(1) were considered implicated in the regulation of proliferation of cultured alveolar type II cells isolated from the adult rats and CDK4 might be a common target against TGFalpha and beta(1) signals.

Animals↗

PubMed1999

[Platelet stereological study in patients with HFRS].

To investigate the effects of stereological alteration of platelets on hemorrhage in hemorrhagic fever with renal syndrome(HFRS), platelet mean cross area(A), area density of alpha-granules(Na), volume density(Vv), the mean open tubule(OCS) and pseudopodia mean(M) were performed stereometric analysis in 12 patients with HFRS. The platelet A was observed, and no significant difference was found compared with the control(P > 0.05), while the number of pseudopodia M was higher, and the open tubule number was lower than those of the control(p < 0.01). The results suggest that in addition to the total platelet count decrement, the quality deterioration and functional activity abnormalities of platelets play an important role on the disordered hemostasis and coagulation in HFRS.

Adult↗