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Biomedical subjects

L Wang

Publications and source records attributed to L Wang.

At least 1,531 records · Page 85Linked to original sources
PubMed1997

[Clonal analysis of blood cells using X-linked HUMARA gene polymorphism].

OBJECTIVE: To explore the method for clonal analysis of blood cells. METHODS: Thirty female AML patients and 20 normal female subjects were analysed by the analysis of X-linked HUMARA gene polymorphism and methylation pattern. RESULTS: The heterozygote rate of HUMARA gene in Chinese women was 88% and the gene had a stable methylation pattern. Out of 20 control females, 17 were heterozygotes and among them 15 were polyclonal, 2 (11.8%) showed skewed X-inactivation. All heterozygote AML were clonal hematopoiesis. CONCLUSION: HUMARA gene polymorphism is a good marker for clonality analysis of blood cells.

Adult↗
PubMed1997

[Experimental studies on the expansion of cord blood CD34+ cells and the improvement of their grafting efficiency].

OBJECTIVE: To elucidate the expanding response of cord blood CD34+ cells to human hematopoietic growth factors (HGFs) and evaluate their grafting efficiency. METHODS: CD34+ cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), expanded with HGFs in a liquid culture system and evaluated of grafting efficiency with a panning assay on an adult bone marrow stroma. RESULTS: The percentage of CD34+ CD38- subset in cord blood was much higher than that in bone marrow or peripheral blood. Treatment with a combination of HGFs, including SCF, IL-3, IL-6, G-CSF,and Epo increased hematopoietic progenitor cells by nearly 100 fold and nucleated cells by more than 500 fold. 68.0%-89.6% of the CD34+ cells treated with HGFs (GM-CSF or IL-3, alone or in combination) seeded in the pre-irradiated marrow stroma, whereas only 36% of the untreated ones did. CONCLUSION: It is possible to expand cord blood CD34+ cells ex vivo and to improve their grafting efficiency with HGFs.

Antigens, CD34↗
PubMed1997

[The implication of circulating CD34+ Thy-1(+) cells measurement during autologous peripheral blood stem cell mobilization].

OBJECTIVE: To estimate the amount of peripheral blood stem cells(PBSC) right during mobilization and determine the optimal time for PBSC collection. METHODS: A serial measurement of circulating CD34+ Thy-1(+) cells were carried out during PBSC mobilization by chemotherapy and granulocyte colony stimulating factor(G-CSF) using dual-color direct immunofluorescence flow cytometry. Colony-culture in vitro was performed at the same time to evaluate the clonogenic capacity of the peripheral blood progenitor cells (PBPCs). RESULTS: Circulating CD34+ Thy-1(+) cells, CD34+ cells and colony-forming cells increased by 48.6-, 50- and 53.1- fold, respectively, after mobilization. The peak levels were reached at 12 approximately 14 days after chemotherapy. The proportion of CD34+ cells and the candidate stem cells, CD34+ Thy-1(+) subset, in mononuclear cells (MNCs) exceeded baseline by 10.5- and 13.8- fold, respectively. The percentage of CD34+ cells coexpressing Thy-1 was highest in the earlist phase of mobilization. CONCLUSION: PBSCs, especially primitive progenitor cells, increased significantly during mobilization with chemotherapy and G-CSF. Flow cytometric assay of circulating CD34 Thy-1(+) cells promptly provides a more reliable indicator for clinical collection of PBSC.

Adult↗
PubMed1997

[Research on the variation of peak shape in capillary zone electrophoresis].

The influence of operation conditions, such as, injection time, applied voltage and effective length of capillary column, on parameters of peak shape in capillary zone electrophoresis (CZE) was investigated by using exponential-modified Gaussian (EMG) equation. The CE experiments were carried out by using the sample of derivatives of benzoic acid and small peptides. The experimens indicated that there was a significant effect of injection time on W1/2 and that the peaks changed from tailing to leading when the injection time was over 3 seconds in the case of pressure injection. It is recommended that an injection time less than 3 seconds can lead to a good column efficiency. The good linear relationships between tm and tau, sigma, W1/2 (t) with different separation voltages were observed. In the range of experimental conditions (11-27kV), higher voltage could lead to smaller zone dispersion, giving rapid and high efficient separation, and the voltage was insignificant on peak tailing. It was also shown that sigma, tau and W1/2 increased slightly with increasing the effective length of capillary column.

Electrophoresis, Capillary↗
PubMed1997

[Determination of inosine in oral tonic by high performance capillary electrophoresis].

This paper describes a high performance capillary electrophoresis method for the assay of inosine in oral tonic. The method employed a boric acid-borate buffer solution with SDS and UV detection at 254 nm. The capillary was 47 cm x 75 microm i.d.. Calibration curve shows good linearity. The recovery of inosine ranged from 95.0%-99.8% with a coefficient of variation (CV) of 2.4% (n=4). This method is simple, rapid and reliable.

Administration, Oral↗
PubMed1997

[Studies on difference of fluorescence activity and elution order of propranolol enantiomers by reversed-phase high performance liquid chromatography].

A sensitive RP-HPLC method for the determination of propranolol enantiomers was developed. It involves the formation of the monoester of propranolol with optically pure (R,R)-O,O'-diacetyl tartaric acid anhydride (DATAAN) in a dry, aprotic solvent with an excess of trichloroacetic acid. The resulting diastereomeric monoesters were easily resolved on a Shim-pack CLC-ODS column with the mobile phase system consisting of different proportions of 2% aqueous acetic acid (adjusted with concentrated ammonia to pH 3.48) and 90% aqueous methanol. And the column effluent was monitored by a fluorescence detector (lambda(ex) 296 nm, lambda(em) 340 nm). In our experiment, a very strong difference of the fluorescence absorbance of the two diastereomers was observed. After having studied chromatographic separation conditions including pH value, ionic strength and the volume percent of organic modifier in mobile phase, we presented the different configurations of the diastereomers and an intra-molecular hydrogen bond which exists only in the (R,R,S) isomer. These could account for the obvious difference of fluorescence activity of two diastereomeric monoesters and their elution order on the reversed-phase column. Our studies show that the intra-molecular hydrogen bond plays an important role on the polarity of the diastereomeric derivatives which determines their elution order and the fluorescence absorbance of the two diastereomers.

Chromatography, High Pressure Liquid↗
PubMed1997

[Preparation and property investigations of nanosized titanium oxide microcrystals].

A naosized TiO2 powder was successfully prepared by the hydrolysis of titanium isopropoxide through sol-gel process. The microstructure of TiO2 powder was investigated by transmission electron microscopy and X-ray diffraction. Both anatase and rutile phases were found in TiO2 powder annealed for 1 hour at 600 degrees C. The characteristics of X-ray photoelectron spectra and infrared spectra could be affected by the size and aggregation state of the microsrystalc constituting the TiO2 powder.

English Abstract↗
PubMed1997

Glucose metabolism in cat outer retina. Effects of light and hyperoxia.

PURPOSE: To determine the roles of oxidation and glycolysis with aerobic and anaerobic lactate formation in the glucose metabolism of the cat outer retina in light and darkness. METHODS: Blood was collected from a choroidal vein and from an artery, and veno-arterial differences in lactate concentration (Lac(v-a) were determined at increasing light intensities. Blood also was sampled under conditions of darkness, light, and hyperoxia and were analyzed for oxygen, glucose, and lactate concentrations with or without blood flow determinations. RESULTS: When the dark-adapted eye was subjected to increasing light intensities, there was a reduction in the Lac(v-a), indicating reduced glycolysis in the outer part of the retina as the rods saturated. In darkness, the mean lactate formation per retina was 0.409 mumol/minute, oxygen consumption was 0.198 mumol/minute, and glucose consumption 0.236 mumol/minute. In light, the corresponding figures were 0.253, 0.166, and 0.123 mumol/minute. Hyperoxia reduced lactate formation and increased oxygen consumption in light and in darkness. CONCLUSIONS: Approximately 80% of the glucose consumed by the outer retina is used primarily in aerobic lactate formation. Because it is more efficient, oxidation of glucose still accounts for most of the energy production in light and in darkness. Light reduces oxidation as well as aerobic and anaerobic lactate formation.

Adaptation, Ocular↗
PubMed1997

Central injection of a new corticotropin-releasing factor (CRF) antagonist, astressin, blocks CRF- and stress-related alterations of gastric and colonic motor function.

The influence of central injection of a new corticotropin releasing factor (CRF) antagonist, astressin, [cyclo(30-33)[D-Phe12,Nle21,38,Glu30,Lys33]r/ hCRF12-41)], on exogenous and endogenous CRF-induced gastric ileus and stimulation of bowel discharges was investigated in conscious rats. Intracisternal (ic) CRF (0.6 microg) reduced gastric emptying of a noncaloric solution to 17.1 +/- 4.9% compared with 50.1 +/- 4.6% in control group injected i.c. with vehicle. Astressin (1,3 and 10 microg, i.c.) dose dependently prevented ic CRF-induced delayed gastric emptying by 33, 100 and 100%, respectively, and had no effect on basal gastric emptying. Abdominal surgery with cecal manipulation (1 min) reduced gastric emptying to 19.8 +/- 5.5% 3 hr postsurgery compared with 59.9 +/- 5.2% after anesthesia alone plus i.c. vehicle. Astressin (1,3 and 10 microg, i.c.) prevented postoperative gastric ileus by 56, 93 and 92%, respectively. Intracerebroventricular CRF (0.6 microg) and water-avoidance stress stimulated pellet output (number/60 min) to 5 +/- 1 and 11 +/- 2, respectively, compared with no fecal pellet output after i.c.v. vehicle and no exposure to stress. Astressin (3 and 10 microg, i.c.v.) blocked exogenous CRF action by 47 and 63%, respectively, and colonic response to stress by 0 and 54%, respectively. These data indicate that astressin injected into the CSF at low doses (1-10 microg) has an antagonistic action against CRF and stress-related alterations of gastrointestinal motor function, without an intrinsic effect in these in vivo systems. Astressin may be a useful tool to explore functional CRF-dependent physiological pathways in specific brain nuclei.

Animals↗
PubMed1997

Simple and reliable methods to assess hepatocyte viability in bioartificial liver support system matrices.

New assays were compared with tritiated thymidine (3HTdR) and trypan blue dye exclusion for evaluating hepatocyte viability on cytodex 3 beads and in microcapsules, the matrices used in bioartificial liver support systems. They were the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) 5 min qualitative assay and the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 -sulfophenyl)-2H -tetrazolium, inner salt (MTS) 1 h quantitative assay. Both tetrazolium salts are cleaved in active mitochondria, the reaction occurring, therefore, in living cells only. After bathing at 39 degrees C with MTT for 5 min, porcine or rat hepatocytes on cytodex 3 beads were detached by collagenase while those in microcapsules were released by citrate treatment or passage through a fine needle. Cell viability was determined directly by microscope. The MTT 5 min metabolic inclusion test and MTS 1 h quantitative assay results correlated closely with those obtained by the 3HTdR, trypan blue dye exclusion, and fluorescein diacetate (FDA) methods. Both the new assays are sensitive, accurate, simple, and time-saving.

Animals↗
PubMed1997

Recombinant 52 kDa Ro(SSA) ELISA detects autoantibodies in Sjögren's syndrome sera that go undetected by conventional serologic assays.

OBJECTIVE: To determine the utility of a recombinant 52 kDa Ro(SSA) ELISA for detecting Ro autoantibodies in Sjögren's syndrome (SS) sera. METHODS: Several different groups of SS sera previously tested for Ro and La(SSB) autoantibodies in clinical diagnostic labs were tested by ELISA with a recombinant human 52 kDa Ro fusion protein. RESULTS: Five of 18 primary SS sera (28%) that had undetectable Ro and La autoantibodies by conventional immunodiffusion (ID) or ELISA in clinical diagnostic laboratories had significant reactivity with a recombinant 52 kDa Ro (r52) ELISA. On repeat testing these 5 sera were again negative for Ro and La antibodies by ELISA with purified 60 kDa Ro and La antigens, but 3 of these sera were reactive with r52 by immunoblot, and immunoprecipitated a 52 kDa protein from human cell extracts. Twelve of 12 primary SS sera that had detectable Ro autoantibodies by ID also reacted with the r52 ELISA, whereas none of 11 normal sera and only one of 27 ID-defined Ro negative systemic lupus erythematosus sera did. Eleven of 28 sera from patients with suspected SS were Ro positive by ID and 60 kDa Ro ELISA. All 11 were also Ro positive by the r52 ELISA. Two of the 28 suspected SS sera were Ro positive by the r52 Ro ELISA, but were Ro and La negative by ID and 60 kDa Ro and La ELISA. CONCLUSION: Anti-52 kDa Ro autoantibodies are frequently present in primary SS sera, but may go undetected by commonly used Ro serologic assays. Our r52 ELISA is more sensitive in detecting Ro antibodies in SS than conventional ID and 60 kDA Ro ELISA.

Antibody Specificity↗
PubMed1997

Role of complement in acute tubulointerstitial injury of rats with aminonucleoside nephrosis.

The present work was designed to elucidate the in vivo role of complement in the proteinuria-associated tubulointerstitial injury. Rats were intravenously injected with puromycin aminonucleoside, and massive proteinuria was observed within 5 days. Prominent tubulointerstitial injury characterized by proximal tubular degeneration, tubular dilatation, and leukocyte infiltration were observed 7 days after injection. C3 and C5b-9 were observed in the luminal side of proximal tubular cells. Renal function, assessed by inulin and para-aminohippurate clearance, was significantly decreased. To-assess the role of complement in this model, rats were injected with either cobra venom factor or soluble recombinant human complement receptor type 1 starting at day 3. These manipulations significantly improved tubulointerstitial pathology and para-aminohippurate clearance without affecting the degree of proteinuria. Deposition of C3 and C5b-9 was not detected in the kidney of rats depleted of complement by cobra venom factor. In rats treated with soluble complement receptor, C3 was still detected in the tubules, but deposition of C5b-9 was not observed. Soluble complement receptor was detected at the site of C3 deposition and in the urine. These data strongly suggest that complement plays a pivotal role in proteinuria-associated tubulointerstitial injury and that systemic complement depletion or inhibition of complement in the tubular lumen may diminish the tubulointerstitial damage.

Animals↗
PubMed1997

An orally active selenium-based antihypertensive agent with restricted CNS permeability.

We report here the first orally active, selenium-based antihypertensive agent, and we demonstrate its restricted CNS permeability using inductively coupled plasma/mass spectroscopy (ICP/MS) and operant behavioral analysis. The biochemistry and pharmacology of selenium are subjects of intense current interest. As a consequence of the redox chemistry of the selenium moiety, phenylaminoalkyl selenides possess the remarkable characteristic of propagating a cycle of turnover-dependent local depletion of reduced ascorbate when processed by the key enzyme of catecholamine metabolism, dopamine-beta-monooxygenase. ICP/MS analysis was used to determine the pharmacokinetic parameters for selenide compounds after i.v. administration to anesthetized rats. Analysis of the data using a two-compartment pharmacokinetic model established very rapid initial clearance and a short beta-elimination half-life from blood. We developed an oxidative procedure for digestion and processing of tissue samples in order to obtain ICP/MS data on the tissue distributions of Se-containing metabolites after the administration of selenide compounds. The results establish that aromatic ring hydroxylation of the selenides results in a marked reduction in brain levels of Se-containing metabolites. The comparative effects of selenide compounds on locomotor activity and operant behavior were then investigated, and the results fully corroborate the ICP/MS analytical results. The novel compound, 4-hydroxy-alpha-methyl-phenyl-2-aminoethyl selenide, exhibits both restricted CNS permeability and oral antihypertensive activity in spontaneously hypertensive rats. This compound is the first orally active selenium-based antihypertensive agent ever reported, and it possesses properties that are highly desirable in pharmacological agents being developed for treatment of chronic diseases such as hypertension.

Administration, Oral↗
PubMed1997

[Prevention of Helicobacter pylori infections in gastroenterological nurses].

The aim of this study was to investigate the state of Helicobacter pylori (Hp) infection in gastroenterology nurses and to prove the effect of gloves on protecting nurses against Hp infection. 157 subjects working in hospitals in Nanjing were investigated, in which there were gastroenterology nurses, and gastroenterologists, and nongastroenterology nurses. All of them were examined for anti-Hp IgG by means of a indirected enzyme-linked immunosorbent assay. No significant difference of the mean absorbence of anti-Hp IgG were found between the gastroenterology nurses and the doctors (P > 0.05). There was significant difference between the two groups of nurses (P < 0.05); There were no statistical significant difference among the three subgroups of gastroenterology nurses, divided as their working duration in the special field. It was concluded gastroenterology nurses was one group of the people who were more easy to be affected with Hp, they will reach the saturation level of catching Hp in the first five years duration, and glove using may reduce incidence of this occupational infection.

Adolescent↗
PubMed1997

Analysis of clonality of lymphocytic leukemia and lymphoma by T-cell receptor gene rearrangement.

OBJECTIVE: To analyse the relationship between the number of T-cell receptor (TCR) gamma gene rearrangement and clonality of malignant cells in lymphocytic leukemia and lymphoma. METHODS: The TCR gamma gene characteristics of 73 cases of lymphocytic leukemia and lymphoma and other diseases that had presented 1 or 2 prominent bands of amplified TCR gamma VI subgroups-J1/2 gene rearrangement (GR) were detected by polymerase chain reaction-restriction enzymes (PCR-RE), heteroduplex formation (HDF), DNA sequencing and single-strand conformational polymorphism (SSCP). RESULTS: Thirty-four percent patients had 2 of TCR gamma GR (biallelic rearrangement); twenty-six percent had 1 of TCR gamma GR; fifty-four percent of acute lymphocytic leukemia's and nineteen percent of non-Hodgkin's lymphomas (NHL) had 2 of TCR gamma GR. HDF could rapidly confirm more than 1 of alleles while more alleles were difficult to be recognized by restriction analysis. Sense and antisense strands of heteroduplex were composed of 2 of TCR gamma GR respectively. By combining HDF method, oligoclonalities in three patients (2 acute lympholytic leukemia and 1 myelodysplastil syndrome and clone evolution in one NHL were found. CONCLUSIONS: The fact that many patients had 2 of TCR GR means that complications of two neoplastic clones can be affirmed only if more than 2 of TCR GR are found. HDF can be used to detect the clonality, oligoclonality and polyclonality of lymphoid cells in lymphocytic leukemia and lymphoma by analysis of the difference of gene segments. HDF is a reliable method for the clone evolution research of lymphoid malignancies in progression.

Base Sequence↗
PubMed1997

Correlative studies of MR findings with neuropathology in Shy-Drager syndrome and striatonigral degeneration.

OBJECTIVE: To determine the pathologic bases of the abnormal signal intensities detected on magnetic resonance imaging (MRI) in Shy-Drager syndrome (SDS) and striatonigral degeneration (SND). METHODS: The correlation of MRI and pathological findings was prospectively evaluated by postmortem scanning of the brain in a case of SDS and another of SND. MRI was performed by using a 1.0 T superconductive magnetic unit, with spin echo (SE) pulse sequences. The brain sections were prepared parallel to the MRI planes. The gross and microscopic pathological studies were conducted according to the corresponding abnormal signal intensities on MRI. RESULTS: In SDS, abnormal hypointense signals on T2 weighted MR images were symmetrically demonstrated in bilateral putamen, where a remarkable positive Prussian blue stain reaction was revealed on pathological examinations. In SND, MRI showed isointense signals on T1 weighted images and hyperintense signals on T2 weighted images in bilateral putamen, and the microscopic findings included necrosis, abundant reactive fibrillary astrocytes and prominence of capillary vascular networks, as well as marked lipofuscin. The number of neurons decreased in both cases. CONCLUSIONS: The demonstration of the abnormal signals in the putamen on MRI is of important value in establishing an antemortem diagnosis of SDS and SND.

Female↗
PubMed1997

Gallstones and their chemical types in relation to serum lipids and apolipoprotein levels.

OBJECTIVE: To determine the profile of lipidemia in patients with gallstones and the characteristics of lipidemia in different kinds of gallstone in gallbladder for predicting high risk subjects predisposed to gallstone formation by means of some serum parameters. METHODS: Serum lipids and apolipoproteins levels in 47 patients with stone in gallbladder (stone group) were compared with those in 19 inpatients without stone (control group). The characteristics of lipidemia in different kinds of gallbladder stones were also compared. RESULTS: Serum apolipoprotein (Apo) A1, C2 and E levels in the stone group significantly increased as compared with the control group (P < 0.01), but there were no statistically significant differences in TC, TG, LDL-C, HDL-C, HDL-C/TC, LDL-C/HDL-C, Apo A2, B and C3 and Apo A1/Apo B levels between the stone and control groups (P > 0.05). Increased levels of serum LDL-C and Apo B and the LDL-C/HDL-C ratio (P < 0.05) were characterized as an index of cholesterol stones, while elevated levels of serum TG and Apo C2 (P < 0.05) as an index of pigment stones. CONCLUSIONS: Serum apolipoproteins might be more sensitive parameters as compared with serum lipids in distinguishing patients with stones from subjects without stones. There are different profiles of serum lipids and apolipoproteins in different chemical types of gallbladder stones.

Adult↗