Biomedical subjects

X Huang

Publications and source records attributed to X Huang.

At least 145 records · Page 8Linked to original sources

PubMed2001

Expression changes of activin A in the development of hepatic fibrosis.

AIM: To examine the expression of activin A, a member of the transforming growth factor (TGFbeta) superfamily, recently has been reported to be overexpressed in liver cirrhosis, in the course of carbon tetrachloride-induced rat hepatic fibrosis. METHODS: Hepatic fibrosis was induced in rats by subcutaneous injections of 40% carbon tetrachloride oily solution for a period of 1 to 7 weeks. At the end of 1, 2, 3, 4, 5, 6 and 7 weeks after carbon tetrachloride injections, the rats were killed in group (6-10 rats each time) for study. The activin A messenger RNA expression and its protein localization were assessed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: The normal rat liver expressed activin A mRNA and protein, and its expression was transiently decreased and became undetectable after carbon tetrachloride injections for 2 or 3 weeks and then increased gradually. After injection of carbon tetrachloride for 6 and 7 weeks, activin A mRNA and protein expressions were significantly enhanced in rat liver. Compared with that of the normal rat liver. Activin A mRNA expression levels in rats receiving carbon tetrachloride injections for 6 and 7 weeks were 1.6 and 2.2 times that of those in normal rat liver respectively (0.456 +/- 0.094 vs 0.2860.0670, P< 0.01; 0.620 +/- 0.134 vs 0.286 +/- 0670, P< 0.01). Immunohistochemistry showed that activin A expressed in hepatocytes of normal liver, and its expression was decreased in rats receiving carbon tetrachloride for 2 or 3 weeks. Compared with normal liver, activin A expression distribution mode changed in fibrotic liver, being increased significantly in hepatocytes around fibrotic areas. CONCLUSION: Activin A expression was increased in late stage of hepatic fibrosis, and this may be involved in hepatic fibrosis formation in this period.

Activins↗

PubMed2001

A synthetic triptycene bisquinone, which blocks nucleoside transport and induces DNA fragmentation, retains its cytotoxic efficacy in daunorubicin-resistant HL-60 cell lines.

In contrast to the parent triptycene (code name TT0), triptycene bisquinone (code name TT2) is cytostatic (IC50: 300 nM) and cytotoxic (IC50: 230 nM) in wild-type (WT), drug-sensitive HL-60 cells (HL-60-S) at day 4. Therefore, the effects of this new quinone antitumor drug were assessed and compared to those of daunorubicin (DAU, daunomycin) in the multidrug-resistant (MDR) HL-60-RV and HL-60-R8 sublines, which respectively overexpress P-glycoprotein (P-gp) or multidrug resistance-associated protein (MRP). In contrast to DAU, which loses its cytostatic [resistance factors (RFs): 22.9-35.7] and cytotoxic (RFs: 23.8-31.3) activities in MDR sublines, TT2 decreases tumor cell proliferation (RFs: 0.9-1.3) and viability (RFs: 0.9-1.5) as effectively in HL-60-S as in HL-60-RV and HL-60-R8 cells at days 2 and 4. Similarly, DAU inhibits the rate of DNA synthesis less effectively in MDR than in parental HL-60 cells (RFs: 8.1-11.9) but TT2 decreases the incorporation of 3[H]-thymidine into DNA to the same degree in HL-60-S, HL-60-RV and HL-60-R8 cells (RFs: 1.2). In contrast to DAU, which is inactive, the advantage of TT2 is its ability to block the cellular transport of purine and pyrimidine nucleosides in WT tumor cells, an effect which persists in both MDR sublines (RFs: 1.0-1.2). Moreover, the concentrations of DAU which induce maximal DNA cleavage in HL-60-S cells at 24 h lose all or most of their DNA-damaging activity in HL-60-RV and HL-60-R8 cells, whereas treatments with 4 microM TT2 produce similar peaks of DNA fragmentation in all WT and MDR cell lines. Since TT2 not only mimics the antitumor effects of DAU but also blocks nucleoside transport and retains its effectiveness in MDR cells that have already developed different mechanisms of resistance to DAU, this new quinone antitumor drug might be valuable to develop new means of polychemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[Painting the chromosomes of fishes with human sex chromosome-specific DNA probes].

Chromosome painting is one of the effective methods in studying the evolution of genomes. The chromosomes of the species of fishes--M. aculeatus, M. albus and D. rerio were painted respectively with human X and Y chromosome-specific DNA probes. The results showed that some homologous segments of human X chromosome were found in the genomes of all the three kind of fishes, all the segments were scattered on several pairs of homologous chromosomes in each kind of fish. But no homologous segment of the human Y chromosome was found.

Animals↗

PubMed2001

[Primed in situ labelling of human metaphase chromosomes].

Primed in situ labelling (PRINS) contributes to the elucidation of the organization of eukaryotic chromosomes and provides an alternative way to localize gene on chromosomes. Here we present the results of random primer and SOX degenerate primer PRINS on human metaphase chromosomes. The particular band pattern of dark and light was observed by using random primer PRINS. SOX degenerate primer PRINS revealed more SOX gene loci and proved further that SOX genes were not clustered on human chromosomes.

Chromosome Mapping↗

PubMed2001

[Collecting of trichloroaniline in the air by micropore filter membrane and determination by gas chromatography].

Trichloroaniline in the air was collected with micropore filter membrane and desorbed with cyclohexane, separated with a column OV-17, OV-210 and determined by GC-ECD. The materals for the filter of collection, solution of desorping and flow-rate of sampling were selected. The detectable limit is 0.01 mg/L. When the concentration of standard solutions is 1-10 mg/L, the relative standard deviation (RSD) is 4.5%-2.3%. There is a linear relation within the range of 0.005-30 mg/L. The sampling efficiency is 98.7%-100%. The samplers were stable for at least 15 days. This method is proved to be accurate, sensitive, fast and simple for sampling and carrying, and it is method is suitable for the determination of trichloroaniline in air, for personal detection and detection in the fields.

Air Pollutants↗

PubMed2001

[Studies on neonatal screening, clinical and gene analysis for tetrahydrobiopterin deficiency in Southern Chinese].

OBJECTIVE: To find out the incidence of tetrahydrobiopterin deficiency(BH4D) among patients with hyperphenylalaninemia in Southern Chinese and evaluate the clinical outcome and gene mutations of tetrahydrobiopterin deficient patients. METHODS: Analyses of urinary neopterin(N) and biopterin(B) were done in 87 patients with hyperphenylalaninemia by high-performance liquid chromatography. The patients with BH4 deficiency and their parents were asked to undergo the gene mutation analysis and the patients were treated and followed up. RESULTS: Eleven cases of which the urinary N/B ratio was higher than 38 and B% lower than 5% were diagnosed as BH4 deficiency caused by 6-pyruvoyl-tetrahydropterin synthase(PTPS) deficiency. The incidence of BH4 deficiency among patients with hyperphenylalaninemia is 12% in Southern Chinese. PTPS gene mutations (P87S, N52S, D96N and G144R) were detected from 5 PTPS deficient families. The G144R mutation is a new mutation. The five PTPS-deficient patients were treated with synthetic BH4, neurotransmitter precursors L-dopa and 5-hydroxytryptophan. They had satisfactory physical and mental development after treatment, and 4 of them scored their IQ 70-80. CONCLUSION: The screening for BH4 deficiency should be carried out in all patients with hyperphenylalaninemia in order to minimize the misdiagnoses.

Biopterins↗

PubMed2001

[Studies on the supercritical-CO2 fluid extraction of complex prescription Danshen-Jiangxiang].

This paper first reported the supercritical-CO2 fluid extraction of complex prescription Danshen-Jiangxiang. With the active constituents and yield of extracts as index, the each other effect of each drug and effect on total complex prescription in extraction were studied. And the effects of pressure and temperature were also studied. The results showed the effects were different in complex prescription extraction and single prescription. Active constituents can be extracted, but a obvious effect exist each other and effects together the yield of extract, extraction rate and content of active constituents of complex prescription extraction, which are concerned in extraction conditions. These study results have important reference on the modernization of traditional Chinese medicines.

Carbon Dioxide↗

PubMed2001

Effects of temperature on biodegradation characteristics of organic pollutants and microbial community in a solid phase aerobic bioreactor treating high strength organic wastewater.

The BOD removal rate and microbial community structure in a solid phase aerobic bioreactor using polyvinyl alcohol gel particles as packing material for the treatment of high strength organic wastewater were investigated at various temperatures. The BOD removal rate in the bioreactor increased when the temperature increased from 20 degrees C to 30 degrees C, 40 degrees C, and 50 degrees C, but it decreased when the temperature increased from 50 degrees C to 60 degrees C. Higher temperature enhanced the endogenous respiration of microbes in the bioreactor. The microbial community structure in the bioreactor was analyzed with quinone profile. The experimental results showed that the microbial community structure in the bioreactor was significantly affected by temperature. The dominant quinone of the microbes inhabiting the bioreactor was ubiquinone-8 at 30 degrees C, but that at 50 degrees C and 60 degrees C was menaquinone-7. It was estimated that the thermophilic Bacillus having menaquinone-7 dominated in the bioreactor at higher temperature. The microbial diversity in the bioreactor varied with temperature.

Bacillus↗

PubMed2001

[Extinction characteristics of TiO2 suspension for different band ultraviolet radiation].

This study focused on the global absorption characteristics of UVA, UVB and UVC radiation in the suspension of titanium-pollutant solution using 4-CBA-Na as a model pollutant. The result showed that the attenuation of ultraviolet in the suspensions conformed to Beer's Law, light intensity negative-exponentially attenuating with the optic path. The extinction coefficient increased with the titanium dosage by a quadratic polynomial law, which may be approximated by a linear function at lower dosage. The sum of the respective UVC or UVB extinction coefficient in pollutant solution and titanium-water suspension was found to approach the measured value in Titanium-Pollutant suspension. Larger extinction coefficient was observed for shorter UV wavelength, implying higher energy efficiency with UVC as ultraviolet source.

Catalysis↗

PubMed2001

Response of avian embryonic brain to spatially segmented x-ray microbeams.

Duck embryo was studied as a model for assessing the effects of microbeam radiation therapy (MRT) on the human infant brain. Because of the high risk of radiation-induced disruption of the developmental process in the immature brain, conventional wide-beam radiotherapy of brain tumors is seldom carried out in infants under the age of three. Other types of treatment for pediatric brain tumors are frequently ineffective. Recent findings from studies in Grenoble on the brain of suckling rats indicate that MRT could be of benefit for the treatment of early childhood tumors. In our studies, duck embryos were irradiated at 3-4 days prior to hatching. Irradiation was carried out using a single exposure of synchrotron-generated X-rays, either in the form of parallel microplanar beams (microbeams), or as non-segmented broad beam. The individual microplanar beams had a width of 27 microm and height of 11 mm, and a center-to-center spacing of 100 microm. Doses to the exposed areas of embryo brain were 40, 80, 160 and 450 Gy (in-slice dose) for the microbeam, and 6, 12 and 18 Gy for the broad beam. The biological end point employed in the study was ataxia. This neurological symptom of radiation damage to the brain developed within 75 days of hatching. Histopathological analysis of brain tissue did not reveal any radiation induced lesions for microbeam doses of 40-160 Gy (in-slice), although some incidences of ataxia were observed in that dose group. However, severe brain lesions did occur in animals in the 450 Gy microbeam dose groups, and mild lesions in the 18 Gy broad beam dose group. These results indicate that embryonic duck brain has an appreciably higher tolerance to the microbeam modality, as compared to the broad beam modality. When the microbeam dose was normalized to the full volume of the irradiated tissue. i.e., the dose averaged over microbeams and the space between the microbeams, brain tolerance was estimated to be about three times higher to microbeam irradiation as compared with broad beam irradiation.

Animals↗

PubMed2001

[The genotype analysis of glucose-6-phosphate dehydrogenase deficiency in Yunnan province].

OBJECTIVE: To identify glucose-6-phosphate dehydrogenase (G6PD) gene mutations in 23 patients with G6PD deficiency and to gain further understanding of the molecular and genetic background of G6PD gene in Yunnan province, China. METHODS: The mutations located in exons 2-12 and in parts of introns of G6PD gene were analyzed by amplification refractory mutation system(ARMS), natural and mis-match primer PCR/restrict enzyme, polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP ) analysis and automatic DNA sequencing. RESULTS: Among these 23 samples, 5 different point mutations in G6PD gene were identified, and they constituted 5 genotypes. There were 7 Han and 3 Dai patients with G487A mutation, 7 cases with both intron 11 T93C and C1311T mutations, 4 cases with intron 5 636 or 637 T-->del mutation, 1 case with G871A mutation, and 1 case with G487A/T93C/C1311T mutation. Two haplotypes, 93C/1311T and 93C/1311T/487A were identified in Yunnan. A strong association was observed between C1311T and the Nla III restriction site produced by intron 11 T93C. The findings of the investigators on IVS-5 636 or 637T-->del in Chinese, on G871A in mainland of China, and on G487A in the Han people of Yunnan have not been reported previously. CONCLUSION: G6PD deficiency is very heterogenous in Yunnan; G487A is one of the common mutations in that province and may be of different origins. Possibly IVS-11 T93C mutation is of non-African origin. IVS-11 T93C and C1311T might jointly result in G6PD deficiency. The above data on G6PD gene mutation types could be useful for clinical diagnosis, prevention of G6PD deficiency, and researches in the origin and migration of minorities in Yunnan or other regions.

Adolescent↗

PubMed2001

[Kinetic study on photocatalytic degradation of p-chlorobenzoate at different light intensities].

Kinetics of photocatalytic degradation were investigated at different light intensities using para-chlorobenzoate as a model pollutant. It was experimentally found that the Langmuir-Hinshelwood model could satisfactorily describe all the kinetic processes. However, the two crucial parameters involved in the L-H model were dependent of the incident light intensity. With elevated light intensity, the rate constant, kr, increased whereas the apparent adsorption constant, Ks, decreased. Grossly, both kr and Ks-1 were correlated with the light intensity in a power law. The experimental discovery implies that the photonic efficiency would be much deteriorated with increased radiation intensity although the reaction rate can be enhanced. Applying mild light intensity might be one of the critical strategies in photocatalytic reactor design to improve the photonic efficiency.

Catalysis↗

PubMed2001

[Effects of emodin on hepatic fibrosis in rats].

OBJECTIVE: To investigate the effect of emodin on hepatic fibrosis in rats and study its possible mechanism. METHODS: The rat hepatic fibrotic model was induced by the subcutaneous injection of 40% CCl(4) (twice a week for 6 weeks). The fibrotic rats were treated with low-dose, mediate-dose and high-dose emodin (20, 40 and 80 mg/kg body weight, once a day for 42 days). Liver function, serum hyaluronic acid, laminin, and liver hydroxyproline were determined, Histopathological changes were examined by optical microscopy. The expression of alpha-smooth muscle actin (alpha-SMA) in liver tissue were detected by immunohistochemical techniques. RESULTS: Compared with model group, it revealed that in emodin-treated rats: (1) Liver functions was improved, alanine transaminase (ALT) and alkaline phosphatase (AKP) obviously reduced (P<0.05 or <0.01), total protein (TP) and albumin (ALB) significantly increased (P<0.05 or <0.01). (2) Serum hyaluronic acid and laminin markedly reduced (P<0.05 or <0.01). (3) Liver hydroxyproline were significantly decreased (P<0.05 or <0.01). (4) The degrees of fibrosis were reduced (P<0.05). (5) The expression of alpha-SMA in liver tissue were ameliorated. CONCLUSIONS: Emodin has an effect on hepatic fibrosis in rats. The effect may be related to slowing hepatocyte injury and inhibiting liver alpha-SMA expressions.

Actins↗

PubMed2001

[Typing of Streptococcus mutans (serotype C) by arbitrarily primed polymerase chain reaction].

OBJECTIVE: To study the relationship between genetic diversity within Streptococcus mutans (C), and dental caries. METHODS: One reference strain (GS5) was used to establish the suitability of primers and the initial AP-PCR conditions. Isolates of Streptococcus mutans (C) were obtained from 19 caries-free and 40 caries-active patients, and were originally isolated on mitis-salivarius-bacitracin agar. Totally 278 isolates were biochemically and serologically confirmed as Streptococcus mutans (C). Chromosomal DNA was extracted from those isolates by Chelex. One random primer, OPA-05 was used as a template in PCR reaction. All amplification reactions were conducted in a volume of 20 microliters containing 2 microliters of 10 x reaction buffer, 200 mumol/L each of dATP, dCTP, dGTP and dTTP and 2.5 units of Taq DNA polymerase. We varied the concentrations of MgCl2 (1.5-4.5 mmol/L), template DNA (2-40 ng), and primer (0.3-0.5 mumol/L) to determine the optical conditions for AP-PCR. The temperature profile in a thermocycler was 35 cycles as follows: 94 degrees C for 1 min, at 36 degrees C for 2 min, at 72 degrees C for 2 min. The initial denaturation was at 94 degrees C for 5 min and the final extension at 72 degrees C for 5 min. RESULTS: The MgCl2 concentration in 4 mmol/L and the primer concentration in 0.5 mumol/L produced clearly distinct and reproducible fingerprints. We found 105 different patterns among the 278 isolates. In high-caries persons more than one genotype isolates of Streptococcus mutans (C) were colonized. CONCLUSIONS: Isolates of Streptococcus mutans (C) exist apparent genetic diversity. The genotypes of isolates might relate to differences in caries susceptibility.

DNA, Bacterial↗

PubMed2001

[The relationship between plasma tumor necrosis factor alpha levels and complications after allogeneic bone marrow transplantation].

OBJECTIVE: To ascertain the implication of tumor necrosis factor alpha (TNF alpha) in the pathogenesis of acute graft-versus-host disease (aGVHD). METHODS: Plasma TNF alpha levels were assessed by ELISA in 243 sera samples from 40 patients who had undergone allogeneic bone marrow transplantation (BMT). Plasma TNF alpha levels were measured before BMT and at different time points after BMT. The results were correlated with aGVHD, infection and conditioning regimen. RESULTS: Plasma TNF alpha levels were significantly higher in patients with grade II and grades III-IV aGVHD (0-4.90) micrograms/L and (0.25-4.21) micrograms/L, respectively than in those with grade 0 or I aGVHD, but there was no clear correlation between plasma TNF alpha levels in patients with grade II and grade III-IV aGVHD. Plasma TNF alpha levels in patients with infection were not statistically different from those in patients without infection. The conditioning regimen did not cause a significant rise in TNF alpha levels. CONCLUSION: It is indicated that TNF alpha may be useful for the diagnosis of aGVHD and for differentiation between aGVHD and other BMT related complications such as infection.

Adolescent↗

PubMed2001

Parkinson's disease and D1 dopamine receptors.

This article reviews the role of the D1-like dopamine receptors in Parkinson's disease (PD), an idea supported by the location of D1 receptors in key aspects of basal ganglia circuitry. The initial disappointing results with available partial D1 agonists have been replaced by optimism as newer full D1 agonists have been shown to be the only class of drugs that can decrease parkinsonism in primates to a degree comparable to levodopa. Most of the available D1 agonists, however, have been plagued by several problems, including poor bioavailability due, at least in part, to the necessity of a catechol function. Three other development issues that have hampered some members of this class are tolerance, hypotension and seizures, although some of the newer drugs entering early development may have escaped these problems. Finally, scientific advances have suggested that therapeutic profiles may be improved either by targeting only one of the two D1-like receptors or by developing drugs that can activate selectively only some D1-mediated functions. These examples suggest that it is highly likely that the immense therapeutic potential of D1 agonists will be realized both in PD and several other important CNS disorders before the end of the decade.

Animals↗

PubMed2001

Arsenic trioxide induces multiple myeloma cell apoptosis via disruption of mitochondrial transmembrane potentials and activation of caspase-3.

OBJECTIVE: To investigate the response of multiple myeloma (MM) cells to arsenic trioxide (As2O3) and their possible mechanisms. METHODS: Two MM-derived cell lines RPMI8226 and U266 cells were used as in vitro models. Cell apoptosis was assessed by morphology, flow cytometry, and DNA gel electrophoresis. Mitochondrial transmembrane potentials (delta psi m) were evaluated by measuring cellular Rhodamine 123 staining intensity. Protein expression was analyzed using Western blot. RESULTS: Zero point one to 0.5 mumol/L As2O3 inhibited cell proliferation and 2.0 mumol/L As2O3 induced cell apoptosis, while 1.0 mumol/L As2O3 inhibited proliferation with a weak degree of apoptosis induction in RPMI8226 and U266 cell lines. As2O3-induced apoptosis was accompanied by mitochondrial transmembrane potentials (delta psi m) collapse and caspase-3 activation in the presence of intact membrane. Glutathione depleter buthionine sulfoximine enhanced, while disulfide bond-reducing agent dithiothreitol partially antagonized As2O3-induced delta psi m collapse and apoptosis in MM cells. All-trans retinoic acid (ATRA) could also induce apoptosis in RPMI8226 cells, but it did not show any cooperative effects with As2O3. CONCLUSION: As2O3 exerts apoptosis-inducing and growth-inhibiting effects on MM cells, and mitochondrium is a pivotal and common target of As2O3 for apoptosis induction.

Antineoplastic Agents↗

PubMed2001

The expression of AT1 receptor on hepatic stellate cells in rat fibrosis induced by CCl4.

OBJECTIVES: To assess the effect of an ACE inhibitor and an Ang II type 1 (AT1) receptor antagonist on preventing hepatic fibrosis induced by CCl4 in rats and to investigate whether there is the expression of AT1 receptors on hepatic stellate cells. METHODS: Studies were conducted in male Sprague-Dawley rats. Except for model group and control group, in three treated groups, either enalapril (5 mg/kg), or losartan (10 mg/kg), or enalapril + losartan were given to the fibrotic rats (daily gavage). Saline vehicle was given to the control group. After 6 weeks, liver fibrosis was assessed directly by hepatic morphometric analysis. The expression of AT1 receptors and alpha-smooth muscle actin (alpha-SMA) in liver tissue and isolated hepatic stellate cells (HSC) were detected by immunohistochemical techniques. RESULTS: Compared with the fibrosis in rats of the model group, rats treated with either enalapril or losartan, or a combination of two drugs, showed a limited expansion of the interstitium (P < 0.05), but no significant difference was observed among the three treated groups (P > 0.05). The expression of AT1 receptors was found in abundance in the fibrotic interstitium of the fibrotic rats, whereas in the normal control rats they were limited to the vascular wall. AT1 receptors were also expressed on activated HSC in culture plates. CONCLUSIONS: Angiotensin-converting enzyme inhibitors and AT1 blockers might slow the progression of hepatic fibrosis. Activated HSCs expressed AT1 receptors. Activation of RAS might be related to hepatic fibrogenesis induced by CCl4.

Alanine Transaminase↗