Biomedical subjects

Q Dong

Publications and source records attributed to Q Dong.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Changes of cardiovascular indices during head up tilt plus lower body negative pressure].

OBJECTIVE: To understand the change of the cardiovascular function and to evaluate the usefulness of sphygmography and heart rate variability (HRV) spectrum techniques on estimating cardiovascular function during HUP + LBNP. METHOD: Blood pressure, ECG, cerebral oxygen saturation and sphygmogram of 16 subjects were studied during 75 degrees head up tilt plus lower body negative pressure (HUP + LBNP). RESULT: (1) During HUP + LBNP, heart rate, blood pressure, normalized low frequency component (LFn), LFn/HFn increased significantly, the cerebral blood oxygen saturation, T wave (ECG), HFn decreased significantly; (2) Blood pressure, heart rate and cerebral blood oxygen saturation decreased significantly in presyncopal state; (3) The heart rate in low tolerance group was higher than that in high tolerance group during the initial stage of HUT + LBNP; (4) The shape of pulse wave changed enormously during HUP + LBNP, so that no analysis could be made. CONCLUSION: HUP + LBNP was an effective approach to examine the regulatory function of cardiovascular system, and the sphygmogram could not be used in studying the regulatory function of cardiovascular system during HUP + LBNP.

Adult↗

PubMed2001

[Studies on liver cancer induced by non-necrotizing dose of diethylnitrosamine in rats].

OBJECTIVE: To provide an appropriate animal model of liver cancer and sensitive indicator for carcinogen risk assessment. METHODS: The developmental processes of liver cancers in rats initiated by non-necrotizing dose of diethylnitrosamine and promoted by phenobarbital were studied. RESULTS: Most of the preneoplastic lesions and liver cancers were made up of eosinophilic cells. The placental glutathione S-transferase (P-GST) staining could allow a lot of positive single cells, foci and nodules to be seen. But the lesions showed by HE staining expressed higher proliferating cell nuclear antigen (PCNA) than those showed by P-GST staining expressed, indicating a greater possibility for these lesions to persist and develop further. The cellular morphologic analysis demonstrated that the ratio of nuclear radii to cytoplasm radii decreased in the cell in PCNA positive expressing nodules. In addition, the nodules showed by P-GST expressed higher PCNA than those the foci expressed, indicating an increased possibility to develop further in the nodules. CONCLUSION: PCNA expression may be used as a relatively ideal marker for predicting the potential development of precancerous lesions in the experimental model of rat liver cancer induction.

Animals↗

PubMed2001

[Study on effect of qingkailing injection and its active principle in inducing cell apoptosis in human acute promyelocytic leukemia].

OBJECTIVE: To investigate the mechanism of Qingkailing (QKL) Injection in treating acute promyelocytic leukemia. METHODS: Using MTT technique, cell morphologic method, DNA gel electrophoresis and flow-cytometry to study the human acute promyelocytic leukemia (HL-60) cell apoptosis induced by QKL and its active principle. RESULTS: QKL and its active principle, Baicalin and hyodeoxycholic acid, showed strong cytotoxicity in inhibiting HL-60 cell, the Bezoar cholic acid showed a weaker effect. Apoptosis could be induced after being treated for 6 hrs by the former three principles, showing a typical apoptosis peak under flow-cytometry, but could not be induced by the latter one. CONCLUSION: QKL could induce leukemia cell apoptosis in vitro, which may be one of the mechanisms of QKLI in curing acute promyelocytic leukemia.

Apoptosis↗

PubMed2000

Deficiency of Src homology 2-containing phosphatase 1 results in abnormalities in murine neutrophil function: studies in motheaten mice.

Neutrophils, an essential component of the innate immune system, are regulated in part by signaling pathways involving protein tyrosine phosphorylation. While protein tyrosine kinase functions in regulating neutrophil behavior have been extensively investigated, little is known about the role for specific protein tyrosine phosphatases (PTP) in modulating neutrophil signaling cascades. A key role for Src homology 2 domain-containing phosphatase 1 (SHP-1), a PTP, in neutrophil physiology is, however, implied by the overexpansion and inappropriate activation of granulocyte populations in SHP-1-deficient motheaten (me/me) and motheaten viable (me(v)/me(v)) mice. To directly investigate the importance of SHP-1 to phagocytic cell function, bone marrow neutrophils were isolated from both me/me and me(v)/me(v) mice and examined with respect to their responses to various stimuli. The results of these studies revealed that both quiescent and activated neutrophils from motheaten mice manifested enhanced tyrosine phosphorylation of cellular proteins in the 60- to 80-kDa range relative to that detected in wild-type congenic control neutrophils. MOTHEATEN: neutrophils also demonstrated increased oxidant production, surface expression of CD18, and adhesion to protein-coated plastic. Chemotaxis, however, was severely diminished in the SHP-deficient neutrophils relative to control neutrophils, which was possibly attributable to a combination of defective deadhesion and altered actin assembly. Taken together, these results indicate a significant role for SHP-1 in modulating the tyrosine phosphorylation-dependent signaling pathways that regulate neutrophil microbicidal functions.

Animals↗

PubMed2000

Cloning of TC-1 (C8orf4), a novel gene found to be overexpressed in thyroid cancer.

A novel gene highly expressed in thyroid cancer, designated TC-1 (thyroid cancer-1), was cloned from suppression subtractive hybridization between papillary thyroid carcinoma and its surrounding normal thyroid tissue. Overexpression of TC-1 in thyroid cancer was confirmed in 15/16 paired samples by RT-PCR and Northern analysis. Ubiquitously expressed in human tissues, the TC-1 sequence showed no homology to any known gene, but matched a cluster of ESTs. After alignment of our sequence with the ESTs, the missing transcription start site was obtained by 5'-RACE and verified by primer extension analysis. The full-length mRNA sequence of 1327 bp has an open reading frame of 321 bp, which encodes a highly conserved protein. Three regulatory motifs were identified at the expected positions within 1 kb of the 5' flanking sequence obtained by genome walking. Using fluorescence in situ hybridization, TC-1 was localized to chromosome 8p11.2. The overexpression of TC-1 in papillary carcinoma suggests that it may have an important role in thyroid carcinogenesis.

Amino Acid Sequence↗

PubMed2000

Assay of glutathione in individual mouse peritoneal macrophages by capillary zone electrophoresis with electrochemical detection.

Glutathione (GSH) in individual mouse peritoneal macrophages was determined by capillary zone electrophoresis with electrochemical end-column amperometric detection at a gold/mercury amalgam microelectrode. A capillary of 20 microm inner diameter was suitable for determination of GSH in an individual macrophage with a good signal-to-noise ratio. Individual macrophages could be drawn into the capillary with the aid of a inverted microscope. Lysing cells was studied in different buffer solutions. 0.01 mol/liter NaOH was selected to lyse macrophages. In this method, the usual calibration curve of GSH could not be used for the quantification of GSH in individual macrophages. It was found that standard GSH injected after analyzing each cell could be served as external standard. The whole cell injection and the lack of necessity of a derivatization reaction lead to more accurate and precise results. The average amount of GSH in an individual mouse peritoneal macrophage is 5.8 fmol, which is consistent with the literature value.

Animals↗

PubMed2000

Measurement of chloramphenicol by capillary zone electrophoresis following end-column amperometric detection at a carbon fiber micro-disk array electrode.

Capillary zone electrophoresis was employed for the measurement of chloramphenicol using end-column amperometric detection with a carbon fiber micro-disk array electrode, at a constant potential of -1.00 V vs. saturated calomel electrode. The effect of oxygen in the buffer has been investigated. It is found that when the area of the carbon fiber electrode is smaller than 1.1 mm2, the interference of oxygen can be overcome. In this procedure deoxygenation is not necessary. The effect of pH, the concentration of the buffer and the high separation voltage across the capillary on the migration time, electrophoretic peak current and separation efficiency has been studied. The optimum conditions of separation and detection are 8.4x10(-4) mol/l HOAc-3.2x10(-3) mol/l NaOAc for the buffer solution, 20 kV for the separation voltage, 5 kV and 5 s for the injection voltage and the injection time, respectively. The calibration plot was found to be linear in the range 5x10(-6) to 1x10(-3) mol/l and the limit of detection is 9.1x10(-7) mol/l or 1.4 fmol (S/N=2). The relative standard deviation is 1.1% for the migration time and 2.3% for the electrophoretic peak current. The method was applied to the determination of chloramphenicol in human serum.

Anti-Bacterial Agents↗

PubMed2000

A new method of quantification of pipemidic-acid by capillary zone electrophoresis with end-column amperometric detection.

Capillary zone electrophoresis was employed for the determination of pipemidic acid using an end-column amperometric detection with a carbon fiber microdisk array electrode, at a constant potential of -1.10 V vs. saturated calomel electrode. The optimum conditions of separation and detection were 1.2 x 10(-4) mol/LNaOAc - 8.8 x 10(-4) mol/ LHOAc for the buffer solution, 20 kV for the separation voltage, 5 kV and 10 s for the injection voltage and the injection time. The limit of detection was 1.05 x 10(-7) mol/L or 189 amol (S/N=3). The relative standard deviation was 0.31% for the migration time and 2.0% for the electrophoretic peak current. The method was applied to determining pipemidic acid in human serum.

Anti-Infective Agents↗

PubMed2000

Quantitative assay of metronidazole by capillary zone electrophoresis with amperometric detection at a gold microelectrode.

Capillary zone electrophoresis was employed for the determination of metronidazole using end-column amperometric detection with a gold microelectrode at a constant potential of -0.52V vs. saturated calomel electrode. To overcome interference of oxygen in the solution, a deaeration injector and a deaeration protector at the detection cell were used. The optimum conditions of separation and detection are 1.0 x 10(-3) mol/L potassium dihydrogen citrate (KH2C6H5O7) for the buffer solution, 20 kV for the separation voltage, and 5 kV and 10 S for injection voltage and injection time, respectively. The limit of detection is 6.0 x 10(7) mol/L or 0.78 fmole (S/N = 3). The relative standard deviation is 3.9% for the electrophoretic peak current. The method was applied to the determination of metronidazole in human urine.

Electrophoresis, Capillary↗

PubMed2000

Monitoring myoglobin by capillary zone electrophoresis with end-column amperometric detection.

Capillary zone electrophoresis was employed for the determination of myoglobin in human urine using end-column amperometric detection with a carbon fiber microelectrode at a constant potential of 1.80 V vs. saturated calomel electrode (SCF). The optimum conditions of separation and detection are: 3.73 x 10-4 mol/L sodium diethyl malonyl urea (barbitone sodium), 1.34 x 10-4 mol/L HCl for the buffer solution, 20 kV for separation voltage, 5 kV and 5 s for injection voltage and injection time, respectively. The limit of detection is 4.4 x 10-8 mol/L or 84 amole signal to noise (S/N = 2). The relative standard deviation is 2.9% for the migration time and 2.5% for the electrophoretic peak current. The method can be used for the determination of myoglobin in human urine. The samples can be directly injected and need no pretreatment. The method is also rapid, less than 2 min, and has a recovery rate of 94-106%.

Electrophoresis, Capillary↗

PubMed2000

Capillary electrophoresis/electrochemical detection system with on-line deoxygenation.

A capillary electrophoresis (CE)/electrochemical detection system with on-line deoxygenation was developed, consisting of a deoxygenation injector, a deoxygenation protector, and an electrochemical detection cell. When the system was utilized for 60 min, the steady-state current of oxygen detected could be dropped to 3% of the original value for the gold/mercury amalgam electrode and to 8% of the original value for the gold electrode, and the limit of detection could be decreased two orders of magnitude for the reducible analytes such as TI+ (from 3.1 x 10-5 mol/L to 8.0 x 10-7 mol/L) and metronidazole (from 3.8 x 10-5 mol/L to 4.0 x 10-7 mol/L).

Electrochemistry↗

PubMed2000

Ethanol enhances TNF-alpha-inducible NFkappaB activation and HIV-1-LTR transcription in CD4+ Jurkat T lymphocytes.

During the latent phase of human immunodeficiency virus type 1 (HIV-1) infection, CD4+ T cells carrying replication-competent proviral HIV-1 DNA play an important role in persistence of the virus. Several cofactors can induce and or amplify HIV-1 replication and negatively affect disease progression and pathogenesis. Ethanol consumption is an important risk factor for HIV-1 infection, and it has been implicated in increased HIV-1 replication and progression of infection. Because tumor necrosis factor-alpha (TNF-alpha) is an important modulator of HIV-1 replication, in the present study we examined the possible effects of ethanol on TNF-alpha-inducible signaling associated with HIV-1 replication in human CD4+ T cells (Jurkat E6-1). We demonstrate that clinically relevant ethanol concentrations significantly potentiate TNF-alpha-inducible NFkappaB. Although ethanol effectively collaborated with TNF-alpha, by itself it did not have a direct effect on NFkappaB activation. The ethanol-dependent potentiation of TNF-alpha-inducible NFkappaB nuclear translocation was observed to involve the enhanced degradation of IkappaBalpha. Additionally, the ethanol-mediated potentiation of TNF-alpha-inducible NFkappaB activation was abrogated by the known antioxidant pyrrolidinedithiocarbamate, suggesting an important mechanistic role for reactive oxygen species in this process. In correspondence with its effect on NFkappaB, ethanol was also observed to significantly enhance HIV-1 long terminal repeat-dependent transcription induced by TNF-alpha. Overall, the data provide a molecular basis for the possible role of ethanol as a cofactor that can adversely affect HIV-1 infection and pathogenesis.

Cycloheximide↗

PubMed2000

Quantitation of caffeine by capillary zone electrophoresis with end-column amperometric detection at a carbon microdisk array electrode.

Capillary zone electrophoresis is employed for the determination of caffeine using end-column amperometric detection with a carbon fiber microdisk array electrode at a constant potential of 1.45 V versus a saturated calomel electrode. The optimum conditions of separation and detection are 0.1 52mM NaH2PO4-0.648mM Na2HPO4 for the buffer solution, 20 kV for the separation voltage, 5 kV for the injection voltage, and 10s for the injection time. The limit of detection is 2.9 x 10(-4)mM or 1.2 fmol (signal-to-noise ratio = 2). The relative standard deviation is 0.68% for the migration time and 2.3% for the electrophoretic peak current. The method is applied to determining caffeine in human serum and a cola drink.

Beverages↗

PubMed2000

Subclavian MR arteriography: reduction of susceptibility artifact with short echo time and dilute gadopentetate dimeglumine.

At arterial phase gadolinium-enhanced magnetic resonance (MR) angiography, artifactual stenosis of the subclavian artery is sometimes seen adjacent to the subclavian vein on the side of the contrast material injection. Experiments in phantoms and in 19 patients showed increased artifact with longer echo time and higher concentration of injected contrast material. An effective method to substantially decrease this susceptibility artifact was threefold dilution of gadopentetate dimeglumine and use of a short echo time (1 msec).

Adolescent↗

PubMed2000

Prevalence and distribution of ret/ptc 1, 2, and 3 in papillary thyroid carcinoma in New Caledonia and Australia.

The world's highest incidence of thyroid cancer has been reported among females in New Caledonia, a French overseas territory in the Pacific located between Australia and Fiji. To date, no molecular genetic studies in this population are available. Over the past few years, the oncogenic rearrangement of the ret protooncogene (ret/ptc) has been studied in papillary carcinomas in different populations. In this study, we investigated the prevalence and distribution of ret/ptc1, 2, and 3 in papillary thyroid carcinoma from the New Caledonian population and compared the pattern with that of an Australian population. Fresh-frozen and paraffin-embedded papillary carcinomas from 27 New Caledonian and 20 Australian patients were examined for ret rearrangements by means of RT-PCR with primers flanking the chimeric region, followed by hybridization with radioactive probes. ret/ptc was present in 70% of the New Caledonian and in 85% of the Australian samples. Multiple rearrangements were detected and confirmed by sequencing in 19 cases, 4 of which had 3 types of rearrangements in the same tumor. This study demonstrates a high prevalence of ret/ptc in New Caledonian and Australian papillary carcinoma. The findings of multiple ret/ptc in the same tumor suggest that some thyroid neoplasms may indeed be polyclonal.

Adolescent↗

PubMed2000

Quality of nucleic acids extracted from fresh prostatic tissue obtained from TURP procedures.

PURPOSE: The molecular genetic study of benign prostatic hyperplasia (BPH) requires high quality nucleic acids from BPH tissue. It has been generally assumed, but not experimentally proven, that the diathermy used in trans-urethral resection of the prostate (TURP) damages nucleic acids. MATERIALS AND METHODS: Total RNA, polyA+ RNA and genomic DNA isolated from fresh tissue obtained from TURP procedures were compared with those isolated from tissue obtained from open prostatectomy. RESULTS: On a formaldehyde agarose gel, there was an increase in low molecular weight RNA in the TURP derived samples, in comparison to that in the open prostatectomy derived samples. The 28S and 18S rRNA were present in all TURP specimens and although the two bands were reduced in some samples, there were samples in which the 2 bands were indistinguishable from the open prostatectomy derived samples. Low molecular weight fragments seen in total RNA were reduced greatly in polyA+ RNA and the difference in polyA+ RNA between the TURP and open prostatectomy derived samples was significantly diminished. RT-PCR of two ubiquitously expressed gene transcripts (Galpha11, 256 bp and HPRT, 847 bp) yielded products of similar size and intensity between TURP and open prostatectomy derived samples. Genomic DNA obtained from TURP derived specimens showed no difference in size or enzyme digestibility in comparison to that from open prostatectomy. CONCLUSIONS: Nucleic acids extracted from fresh prostatic tissue derived from TURP procedures can be used as readily as any other fresh tissue for RT-PCR based molecular genetic studies, although polyA+ RNA isolation is recommended if degradation-free RNA is required.

DNA↗

PubMed2000

CT scanning and arthroscopic evaluation of patellofemoral malalignment.

OBJECTIVE: To determine the pattern of malalignment and the extent of chondral damage, the patellofemoral joint was evaluated by CT scanning and the findings were proved by arthroscopic examination. METHODS: In 20 cases, 40 knees were examined by CT scanning with and without quadriceps contraction in order to differentiate between static and dynamic abnormalities. The CT images were analyzed. The arthroscopic examination was carried out for 27 knees in 20 cases. RESULTS: Ten knees had static patellar lateral subluxation and 16 knees dynamic lateral subluxation. Eleven knees had static patellar lateral tilt, and 7 knees dynamic tilt. All of the 27 knees showed arthroscopic patellar maltracking and chondral damage. CONCLUSIONS: The patellofemoral alignment, affection of quadriceps, and the extent of tight retinaculum may be precisely evaluated by CT measurement and proved by arthroscopic examination.

Adult↗

PubMed2000

[Effects of tail suspension on learning and memory function of mice].

Objective. To study the effects of simulated weightlessness on learning and memory capability of the brain. Method. Accuracy fraction, error frequency and pass rate were observed among control, restrained control, tail suspended (TS) control, restrained, and tail suspended mice in square water maze tests. And latent period and error time were observed in control and 30 degrees tail suspension mice in step down test. Result. The indices did not change significantly during learning period. Accuracy fraction of tail suspended group was reduced significantly in the tests as compared with pretest values. In step down test, latent period and error time showed no difference between TS 5 h and 2 d in untrained mice, but shortened evidently after TS 2 d and prolonged after TS 7 d in trained mice, which suggested the degradation of learning and memory ability after TS 5 h and 2 d respectively. Conclusion. Acute tail suspension depressed brain's learning ability and quality, while tail suspension of 7 d and 12 d impaired the spatial memory in mice.

Animals↗