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Biomedical subjects

W Huang

Publications and source records attributed to W Huang.

At least 325 records · Page 18Linked to original sources
PubMed1999

[Study of TEL-AML1 fusion gene in childhood B-lineage acute lymphoblastic leukemia].

OBJECTIVE: To determine the incidence of TEL-AML1 fusion gene and its role in clinical diagnosis and prognosis of childhood B-lineage acute lymphoblastic leukemia (B-ALL), and to compare the two techniques: nested RT-PCR and dual-color fluorescence in situ hybridization (FISH). METHODS: Nested RT-PCR and dual-color FISH techniques were used to detect TEL-AML1 fusion gene. RESULTS AND CONCLUSION: TEL-AML1 fusion transcript was found in 22.5%(9/40) of patients with B-ALL by RT-PCR. The prognosis of these TEL-AML1 positive patients was relatively good and the complete remission rate was 100%. Both RT-PCR and FISH techniques were proved to be useful for detecting TEL-AML1 fusion gene and suitable for clinical diagnosis and prognosis evaluation.

Adolescent↗
PubMed1999

Effect of lithium on growth of bone marrow stromal cells.

OBJECTIVE: To investigate the effect of lithium on the growth of bone marrow stromal cells. METHODS: We compared the different effects of lithium with the concentration of 0.1-12 mmol/L on the growth of murine fibroblast colony forming unit (mCFU-F), human fibroblast colony forming unit (hCFU-F) and their intercolonial cells. Pure murine bone marrow stromal cell assay was used to investigate the mechanism. RESULTS: Cultures with 1-4 mmol/L lithium resulted in significant increase in the number of hCFU-F, but distinct decrease in the number of mCFU-F. Furthermore, there were much more endothelial cells between mCFU-Fs than those between hCFU-Fs. The direct effect of 1-4 mmol/L lithium on the growth of pure murine fibroblasts and endothelial cells was stimulatory. Serum-free endothelial cell conditioned medium (EC-CM) could inhibit the growth of mCFU-F. CONCLUSIONS: 1-4 mmol/L lithium has stimulatory effect on the growth of pure murine fibroblasts and endothelial cells. The inhibitory effect of lithium on mCFU-F formation may result from the effect of increased endothelial cells.

Animals↗
PubMed1999

[Functional reconstruction of mandible by using vascularized fibular free flap and one-stage rehabilitation of the implant].

OBJECTIVE: To study the characteristics of the vascularized fibular free flap and the possibility of the insertion of implant at the same time. METHODS: The microvascular surgical procedure and implant technique were used in the treatment of two cases suffered from mandibular ameloblastoma. After tumor resection by partial mandiblectomy, graft of vascularized fibular free flap was performed with simultaneous insertion of 5 implant. RESULTS: One year later, the grafted bone was survival, the osseointegration was proceeded between the implant and grafted bone. The functional reconstruction of the mandible was excellent after prosthetic denture. CONCLUSION: This is a good approach to rehabilitate bone function by using vascularized fibular free flap and one-stage implant placement.

Adult↗
PubMed1999

[Study on the crystal heat treatment schedule of Plat-II castable ceramic].

OBJECTIVE: To establish the crystal heating schedule of Plat-II castable ceramic materials. METHODS: This study first identified the thermal limits of Plat-II castable ceramic crystallization basing on DTA exotherm analysis, then the crystal density of various heating schedule was observed by scanning electron microscope. RESULTS: The efficient crystal heating schedule of Plat-II castable ceramic was established: The temperature was increased from the room temperature to 620 degrees C with the speed of 10 degrees C/min, kept 20 min, then was increased continually to 670 degrees C with the speed of 5 degrees C/min, and kept 30 min. CONCLUSION: The establishment of the crystal heat treatment schedule of Plat-II castable ceramic will become the basis for the further study.

Crystallization↗
PubMed1999

[The high-resolution CT scan of facial nerve injury following temporal bone fracture].

OBJECTIVE: To discuss the applied value of the high resolution CT scan in the facial nerve injury induced by the temporal bone fracture. METHOD: Thin slice temporal bone CT scans were conducted in 28 cases of facial nerve injuries following head trauma and operations were performed according to temporal bone CT scan and clinical manifestation. RESULT: 6 cases recovered nearly to normal; 18 cases partially recovered and 4 cases were without any change. CONCLUSION: The high resolution CT scan can show the fracture line's location and trend. It is of help to decide the injury site as well as other related injuries and to choose an appropriate surgical approach.

Adolescent↗
PubMed1999

[Changes of CGRP activity and distribution in facial nucleus after facial nerve injury of guinea pig].

OBJECTIVE: In order to study the changes of CGRP activity in facial nucleus of guinea pig after facial nerve injury. METHOD: The activity of CGRP was detected by the technique of immunohistochemical and image analysis methods were used. RESULT: It was showed the there were CGRP-immunoreactivity (IR) in normal facial nucleus and its' subnucleus. An initial increase of CGRP-IR was noted and the content of CGRP under image analysis were significantly different when compared with control group (P < 0.01) at day 1 after injury of facial nerve. CGRP continued to rise to a maximal level at day 7 (P < 0.001). And after which it gradually decreased. We noticed distinct bundle-shaped CGRP fibers elongated to the peripheral part from ventral facial nucleus in the period of 14 d-35 d. CONCLUSION: It suggests that during the course of facial nerve regeneration following injury, CGRP changed characteristically. CGRP may play the regulational role in facial nerve regeneration.

Animals↗
PubMed1999

[Clinic and immunophenotypic studies on midline malignant histiocytosis].

OBJECTIVE: To understand the clinic opatholgic changes of midline malignant histiocytosis (MMH), and to explain the source of atypical lymphoid cells (ALC) of MMH, so as to search after the relation between MMH and malignant lymphoma. METHOD: Histopathologic section of 39 cases of MMH were taken HE staining and the histopathologic changes were obsered under microscope. The immunohistochemical staining was also used to examine the immunophenotype of ALC. RESULT: 1. Pathologic changes of MMH: coaglation necrosis and mixed inflammatory cells infiltration, with epithelial infiltration which distributed around the center of blood vessel were their characteristics. 2. Immunohistochemical staining result: 28 in 39 cases of MMH (71.8%) expressed the immunophenvtype of T-cell; among them 13 (33.3%) were finded both positive reaction to CD3 and CD57 antigens with ALCs at the same time. CONCLUSION: According to immunophenotypic studies, most ALCs came from proliferation and infiltration of atypical T cell. ALCs of MMH expressed not only T-cell markers (CD3), but also NK-associated antigen (CD57). MMH was a mucosa related peripheral T/NK cell lymphoma originally.

Adult↗
PubMed1999

[Expression of genes aroG and pheA in phenylalanine biosynthesis].

aroG and pheA genes, encoding 3-Deoxy-D-arabinoheptulonate-7-phosphate synthase(DS) and Chorismate mutase (CM)-prephenate dehydratase(PD) in the pathway of phenylalanine biosynthesis respectively, were amplified by polymerase chain reaction(PCR). The genes were assembled on the multicopy vectors and expressed in both Escherichia coli and Brevibacterium. The products of two gene were detected by SDS-PAGE. The activities of relevant enzymes were measured in the crude extract of the host strain. When aroG-pheA genes were introduced into E. coli p2392, the activities of DS, CM and PD were increased by 4.3-fold, 4.4-fold and 2.2-fold respectively. Whereas in the case of Brevibacterium flavum 2732, the activities of DS, CM and PD were increased by 12.3-fold, 2.3-fold and 5.6-fold, respectively. As the results, the overproduction of phenylalanine was brought about by using the genetic engineering strain of B. flavum.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed1999

[The effect of erycibele alkaloid on intracellular Ca2+ mobilation of cultured human ciliary muscle cells].

PURPOSE: To study the effect of erycibele alkaloid on cultured human ciliary muscle intracellular Ca2+ movement. METHODS: Intracellular Ca2+ was studied by Fura-2 probe and muscarinic antangonist was applied. RESULTS: Erycibele alkaloid had no any possible disturbulance on the examination system. The average resting[Ca2+]i was 79.3 +/- 28.7 nmol/Lol/L (n = 24). Erycibele alkaloid caused biphase [Ca2+]i elevation. Non-selective muscarinic antagonist Atropine (1 nmol/L) could completely block the 1 mumol/L erycibele alkaloid induced [Ca2+]i elevation; M1 antagonist Pirenzipine could not block the 1 mumol/L erycibele alkaloid induced [Ca2+]i elevation in low concentration (0.03 nmol/L) but in higher concentration (1 nmol/L). M3 antagonist 4-diphenyl acetoxy N-methy piperidine methiodide could completely block the 1 mumol/L erycibele alkaloid induced [Ca2+]i elevation in low and high concentration. CONCLUSION: The effect of erycibele alkaloid on increasing cultured human ciliary muscle cell intracellular Ca2+ is mediated by M3 receptor subtype.

Biological Transport, Active↗
PubMed1999

[Deferoxamine protects against gentamicin ototoxicity].

OBJECTIVE: To study the prevention of gentamicin(GM) ototoxicity by deferoxamine(DFO) in the guinea pig. METHODS: Guinea pigs were randomly assigned to three experimental groups (GM-treated alone, DFO-treated alone, GM and DFO in combination) and one control group. Acoustic brainstem response (ABR), the surface preparation and transmission electron microscopy were utilized to evaluate the hearing thresholds and the cochlear morphology. To explore the mechanism associated with deferoxamine protection, serum levels of GM, BUN and Cr, together with concentration of MDA, SOD and iron in cochlear and renal tissues were measured. RESULTS: The GM group developed up to 40-60 dB of the threshold shifts at 8 kHz while the GM + DFO group developed only 15-25 dB of the threshold shifts (P < 0.05). Moorphological changes were consistent with functional changes. DFO did not alter serum levels of GM. Renal function of GM group was damaged obviously. However, changes of MDA, SOD and iron were not significant (P > 0.05). MDA and iron concentrations in cochlear tissue of the GM + DFO group were significantly lower than those in the GM group (P < 0.05) while SOD level was much higher than that in GM group. CONCLUSION: This study suggests that free radical and iron involve in GM ototoxicity and DFO may become a promising therapeutic agent that can be used to reduce gentamicin ototoxicity.

Animals↗
PubMed1999

[Analysis of odoriferous pollutants in cooling water by on-line LC-GC/FTIR method].

The integration of two dimensional chromatography system (LC-GC) has ability for clean-up, enrichment, pre-separation and high resolution separation for the sample. The coupling of LC-GC with FTIR can notably improve the detection ability of conventional (light pipe) GC/FTIR system. The interface of LC-GC system employs retention gap technique (15 m x 0.53 mm i.d. retention gap column and 4 m x 0.25 mm i.d. precolumn) with on-column injection and partially concurrent solvent evaporation with early vapor exit. The applicability of the method is demonstrated by the analysis of odoriferous pollutants (phenolic compounds) in the cooling water with 15 cm x 2 mm i.d. silica LC column and 35 m x 0.25 mm i.d. OV-101GC column under the conditions of haxane/dichloromethane (80:20) as the mobile phase (0.3 mL/min) of LC, N2 as the carrier gas in GC and solvent evaporation temperature 80 degrees C, inlet pressure of 0.2 MPa etc. The method of on-line coupled LC-GC/FTIR is a reliable analytical tool for microcomponents in complex mixtures.

Chromatography, Gas↗
PubMed1998

Affinity purification and partial characterization of a yeast multiprotein complex for nucleotide excision repair using histidine-tagged Rad14 protein.

The nucleotide excision repair (NER) pathway of eukaryotes involves approximately 30 polypeptides. Reconstitution of this pathway with purified components is consistent with the sequential assembly of NER proteins at the DNA lesion. However, recent studies have suggested that NER proteins may be pre-assembled in a high molecular weight complex in the absence of DNA damage. To examine this model further, we have constructed a histidine-tagged version of the yeast DNA damage recognition protein Rad14. Affinity purification of this protein from yeast nuclear extracts resulted in the co-purification of Rad1, Rad7, Rad10, Rad16, Rad23, RPA, RPB1, and TFIIH proteins, whereas none of these proteins bound to the affinity resin in the absence of recombinant Rad14. Furthermore, many of the co-purifying proteins were present in approximately equimolar amounts. Co-elution of these proteins was also observed when the nuclear extract was fractionated by gel filtration, indicating that the NER proteins were associated in a complex with a molecular mass of >1000 kDa prior to affinity chromatography. The affinity purified NER complex catalyzed the incision of UV-irradiated DNA in an ATP-dependent reaction. We conclude that active high molecular weight complexes of NER proteins exist in undamaged yeast cells.

Chromatography, Affinity↗
PubMed1998

Identity of the organic cation transporter OCT3 as the extraneuronal monoamine transporter (uptake2) and evidence for the expression of the transporter in the brain.

We investigated the transport of cationic neurotoxins and neurotransmitters by the potential-sensitive organic transporter OCT3 and its steroid sensitivity using heterologous expression systems and also analyzed the expression of OCT3 in the brain. When expressed in mammalian cells, OCT3 mediates the uptake of the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) and the neurotransmitter dopamine. Competition experiments show that several cationic neuroactive agents including amphetamines interact with OCT3. When expressed in Xenopus laevis oocytes, OCT3-mediated MPP+ uptake is associated with inward currents under voltage-clamp conditions. The MPP+-induced currents are saturable with respect to MPP+ concentration, and half-maximal saturation (K0.5) occurs at about 25 microM MPP+ with membrane potential clamped at -50 mV. The K0.5 for MPP+ is markedly influenced by membrane potential. OCT3 is inhibited by several steroids, and beta-estradiol is the most potent inhibitor (Ki approximately 1 microM). The pattern of steroid sensitivity of OCT3 is different from that of OCT1 and OCT2 but correlates significantly with that of the extraneuronal monoamine transporter (uptake2). The transport characteristics and steroid sensitivity provide strong evidence for the molecular identity of OCT3 as uptake2. OCT3 is expressed in the brain as evidenced from Northern blot analysis, reverse transcription-polymerase chain reaction, and in situ hybridization using OCT3-specific probes. The molecular identity of the transcript hybridizing to the probe has been established by sequencing the reverse transcription-polymerase chain reaction product and also by the isolation of the OCT3 cDNA from a brain cDNA library. Regional distribution studies with in situ hybridization show that OCT3 is expressed widely in different brain regions, especially in the hippocampus, cerebellum, and cerebral cortex. OCT3 is likely to play a significant role in the disposition of cationic neurotoxins and neurotransmitters in the brain.

1-Methyl-4-phenylpyridinium↗
PubMed1998

Characterization of the calcium site in two complement-like domains from the low-density lipoprotein receptor-related protein (LRP) and comparison with a repeat from the low-density lipoprotein receptor.

Calcium is required for the binding and endocytosis of protein ligands by the low-density lipoprotein receptor-related protein (LRP) and other members of the low-density lipoprotein (LDL) receptor family. Calcium binding sites are thought to be present in the complement-like repeats that occur in clusters in all members of this receptor family. We have expressed two such complement-like repeats, CR3 and CR8, from an alpha2-macroglobulin-proteinase ligand binding region of LRP, as well as repeat 1 from the LDL receptor and examined the metal binding properties and resulting structural changes of these three repeats using changes in tryptophan and terbium fluorescence and perturbation of [1H-15N]-HSQC NMR spectra of the 15N-labeled domains from LRP. We found that all three domains contain a tight calcium binding site at physiological pH and that calcium binding results in a major structural rigidification. Changes in tryptophan fluorescence and tryptophan-sensitized terbium fluorescence indicate that the calcium binding sites are located in homologous regions in all of the repeats. Differences in the details of the perturbations, as well as in the pH dependence of calcium binding, show, however, that each metal site is distinct.

Amino Acid Sequence↗
PubMed1998

IL-17 stimulates granulopoiesis in mice: use of an alternate, novel gene therapy-derived method for in vivo evaluation of cytokines.

IL-17 is a novel cytokine secreted principally by CD4+ T cells. It has been shown to support the growth of hemopoietic progenitors in vitro; however, its in vivo effects are presently unknown. Adenovirus-mediated gene transfer of the murine IL-17 cDNA targeted to the liver (5 x 10(9) plaque-forming units (PFU) intravenous) resulted in a transiently transgenic phenotype, with dramatic effects on in vivo granulopoiesis. Initially, there was a significant increase (fivefold) in the peripheral white blood count (WBC), including a 10-fold rise in the absolute neutrophil count. This was associated with a doubling in the spleen size over 7-14 days after gene transfer, which returned to near baseline by day 21, although the white blood cell count remained elevated. There was a profound stimulation of splenic hemopoiesis as demonstrated by an increase in total cellularity by 50% 7 days after gene transfer and an increase in hemopoietic colony formation. A maximal increase in frequency of high proliferative potential colonies (HPPC) (11-fold) and CFU-granulocyte-macrophage (GM) and CFU-granulocyte-erythrocyte-megakaryocyte-monocyte (GEMM) (CFU) (6-fold) was seen on day 3 after IL-17 gene transfer. Both CFU and HPPC remained significantly elevated in the spleen throughout day 21, but at reduced levels compared with day 3. Bone marrow CFU and HPPC were elevated on day 3 only by 75% and 25%, respectively, without changes in total cellularity. Thus, murine IL-17 is a cytokine that can stimulate granulopoiesis in vivo. Since IL-17 is principally produced by CD4+ T cells, this cytokine could have therapeutic implications in AIDS-related bone marrow failure and opportunistic infections.

3T3 Cells↗
PubMed1998

Use of intrinsic modes in biology: examples of indicial response of pulmonary blood pressure to +/- step hypoxia.

Recently, a new method to analyze biological nonstationary stochastic variables has been presented. The method is especially suitable to analyze the variation of one biological variable with respect to changes of another variable. Here, it is illustrated by the change of the pulmonary blood pressure in response to a step change of oxygen concentration in the gas that an animal breathes. The pressure signal is resolved into the sum of a set of oscillatory intrinsic mode functions, which have zero "local mean," and a final nonoscillatory mode. With this device, we obtain a set of "mean trends," each of which represents a "mean" in a definitive sense, and together they represent the mean trend systematically with different degrees of oscillatory content. Correspondingly, the oscillatory content of the signal about any mean trend can be represented by a set of partial sums of intrinsic mode functions. When the concept of "indicial response function" is used to describe the change of one variable in response to a step change of another variable, we now have a set of indicial response functions of the mean trends and another set of indicial response functions to describe the energy or intensity of oscillations about each mean trend. Each of these can be represented by an analytic function whose coefficients can be determined by a least-squares curve-fitting procedure. In this way, experimental results are stated sharply by analytic functions.

Animals↗