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Biomedical subjects

L Huang

Publications and source records attributed to L Huang.

At least 145 records · Page 8Linked to original sources
PubMed2001

[Allogeneic peripheral blood stem cell transplantation for treatment of leukemia].

OBJECTIVE: To observe engraftment kinetics, incidence and severity of graft-versus-host disease (GVHD) and clinical outcome in 40 recipients undergoing allogeneic peripheral blood stem cell transplantation (allo-PBSCT). METHODS: 40 leukemia patients with a median age of 35 years underwent allo-PBSCT from June 1997 to May 1999. PBSC were mobilized with G-CSF at a dose of 5 microg/kg S. C. every 12 hours for 5 days. A median of 7.7 (range 2.0 to 16.8) x 10(6) CD(34)(+) cells/kg was infused into the recipients. Busulfan (BU) and cyclophosphamide (CY) were used as conditioning regimen. All patients received cyclosporine A and either methotrexate (n = 34) or methylprednisolone (n = 6) for GVHD prophylaxis. RESULTS: Engraftment of neutrophils and platelets was achieved at a median of day + 13 (9 - 28) and day +12 (7 - 60) respectively. Patients receiving >or=4 x 10(6) CD(34)(+) cells/kg or given G-CSF post transplant had significantly accelerated neutrophil and platelet engraftment. Acute GVHD occurred in 17 of the 40 patients (42.5%), with grade II-IV acute GVHD in 10 patients (25.0%); chronic GVHD developed in 21 out of the 30 evaluable patients (70.0%) with a median follow up of 480 days (range 300 - 1,000). The transplant related mortality is 20.0% and the relapse rate is 10.0%. The probability of leukemia free survival at 3 years is 70.0%. CONCLUSIONS: These results indicate that allo-PBSCT can provide rapid hematopoietic reconstitution without an increased incidence of acute GVHD, but may be associated with high risk of chronic GVHD.

Adult↗
PubMed2001

[Leaf decomposition of two species in a mangrove community in Futian of Shenzhen].

Using litter bags, the authors studied the dynamics of dry weight and organic C, N and P of leaves of two species (Kandelia candel, Aegiceras corniculatum) in a mangrove community in Shenzhen during their decomposition in situ. Leaves of K. candel degraded more rapidly than those of A. corniculatum. For A. corniculatum, it needed 35 days to lose half initial ash-free dry weights (AFDW) of the leaves, while for K. candel, only 12 days. Despite the difference in loss rate of litter bags with the two species, the dynamics of organic C, N and P of leaf detritus followed the same pattern. During decomposition, the N concentration of leaf detritus of both species rose up sharply, and then decreased gradually from the peak. The P level declined slightly, and then rose up slowly. The concentration of C remained fairly constant throughout the experiment. No significant difference in decomposition rates of the leaves of A. corniculatum was found when they degraded at different positions along tidal gradient within the mangrove ecosystem.

Carbon↗
PubMed2001

[Comparison of nerve fiber layer thickness between optical coherence tomography and histomorphometry in glaucomatous monkey eyes].

OBJECTIVE: To correlate the retinal nerve fiber layer (NFL) thickness measured by optical coherence tomography (OCT) in vivo with histomorphometric measurement. METHODS: Four laser-induced glaucomatous eyes of 4 cynomolgus monkeys were studied by OCT scanning a circular area 2.4 mm in diameter around the optic nerve head. The 4 eyes had early or advanced glaucoma. After final OCT measurement, the monkeys were sacrificed and the eyes enucleated. Routine serial section preparations were made, stained with hematoxylin and eosin, and the NFL thickness of 526 sections measured with the aid of a computerized image analysis system was compared with that at the points coincident with the OCT scanned. RESULTS: The mean OCT and histomorphometric NFL thickness in glaucoma were (72.2 +/- 54.5) microm and (61.1 +/- 44.2) microm, after the correction of dehydration 15% (70.3 +/- 51.1) microm respectively. Student's t-test showed that the difference was insignificant (t = 1.895, P > 0.05). CONCLUSIONS: The NFL thickness measured by OCT in vivo correlates well with that by histomorphometry, and the measurement is accurate.

Animals↗
PubMed2001

[Human cytomegalovirus inhibits the proliferation of CFU-MK in vitro].

OBJECTIVE: To investigate the effect of human cytomegalovirus (HCMV) on the proliferation of colony forming unit-megakaryocyte (CFU-MK). METHODS: Semi-solid CFU-MK culture system was used to observe the effect of HCMV AD169 strain on CFU-MK growth of 20 cord blood samples. HCMV DNA and immediate early antigen (IEA) mRNA in CFU-MK were detected by in situ-polymerase chain reaction (IS-PCR) and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: HCMV AD169 suppressed the differentiation and proliferation of CFU-MK in vitro significantly. The suppression was in a dose-dependent fashion. HCMV DNA was successfully detected in colony cells from viral infection group, and did the expression of HCMV IEA mRNA. CONCLUSION: HCMV AD169 can directly infect megakaryocyte progenitor and suppress their proliferation and differentiation.

Cell Proliferation↗
PubMed2001

[New evidences for adapting Qian jin yao fang (Thousand golden essential prescriptions) by Office of Revising Medical Books of the Song dynasty].

Qian jin yao fang (Thousand Golden Essential Prescriptions) written by Sun Simiao in the Tang dynasty has two kinds of extant editions in circulation: one is the revised edition, Bei ji qian jin yao fang (Essential Prescriptions Worth a Thousand Gold for Emergencies) revised by the Office of Revising Medical Books of the Song dynasty, the other is the Song edition, Sun zhenren qian jin fang (Master Sun's Thousand Golden Prescription) (20 volumes extant) not revised by Song people. There are great discrepancies between these two editions not only in the order of chapter contents, including the order of items in the same chapter, but also in its texts. Concerning the causes of this difference, we already made preliminary analysis in our former paper. However, there are new evidences to further explain it with our recent research.

China↗
PubMed2001

[A study of bone development and metabolism in childhood].

OBJECTIVE: To explore the regularity of bone development and metabolism in childhood. METHODS: A survey was made to collect and analyze the data on bone biochemistry, the density of lumbar vertebrae and the X-ray examination of calcaneus in 224 healthy children aged 3-15 years in the urban area of Chengdu. RESULTS: Comparative analysis of serum and urine calcium and phosphate concentrations showed no significant difference between the age groups. The serum alkaline phosphatase (ALP) and bone alkaline phosphatase (BALP) were found to increase with age and reach their peak values in children aged 7-12 years, and their values were significantly higher than that of adults (P < 0.05). The density of lumbar vertebrae and the trabecular bone of calcanesus also developed with age. CONCLUSION: The measurements of the bone biochemistry, bone density and the trabecular bone of calcaneus which reflect the bone development and metabolism have their special regularity in childhood. The criteria in use for adulthood is not fit for the evaluation in childhood. The data obtained can be used in clinical diagnosis and treatment of the bone metabolic diseases of children.

Adolescent↗
PubMed2001

[One stage otoplasty treatment for congenital malformations of the auricle and middle ear].

OBJECTIVE: To investigate the application of one stage otoplasty for congenital atresia of the external acoustic canal and malformations of the middle ear and the auricle. METHOD: Patients with the ear malformations were given surgical reconstruction of one stage otoplasty. The auricle was reconstructed with the rib which was encapsulated with the superthin temporal flap. According to the malformations of the middle ear in patients, I style tympanoplasty and III style tympanoplasty were carried out respectively. All patients were performed myringoplasty with temporal fascia and reconstructed the external acoustic canal with full thickness skin-grafting. RESULT: A long term follow-up (4-6 years) demonstrated that 11 ears were survival of which 8 ears figuration were ideal. The hearing improvement was observed in all patients. CONCLUSION: One stage otoplasty is effective for treatment of the congenital malformations of the external and middle ear.

Adult↗
PubMed2001

[Extraction of DNA from environmental samples and construction of mixed genomic DNA libraries].

A method has been developed for extracting and purifying genomic DNA from environmental samples. In this method, an environmental sample is treated first by grinding and freezing/thawing and subsequently by SDS/proteinase K-based DNA extraction. The yields of purified DNA from three samples used in this study ranged from 2 to 16 micrograms per gram of dry sample. Mixed genomic DNA libraries for two of the environmental samples were constructed by inserting restriction fragments (3-8 kb) of the purified DNAs into plasmid pUC18 and transforming E. coli DH5 alpha with the resultant plasmids. Approximately 10(3) to 10(4) insert-containing clones were obtained from 1 g of each sample. Clone libraries were analyzed by DNA sequencing and gene annotation. Among 20 randomly-selected clones, 14 contained an insert whose sequence had not been reported while the rest had an insert of either E. coli or vector origin. A search of sequence databases using the end sequences of each of the foreign inserts showed that each sequence was part of a gene encoding, in most cases, a predictable function. Our results are of significance to the collection, investigation and exploitation of the genes of uncultured microorganisms.

Amino Acid Sequence↗
PubMed2001

[Purification and characterization of a DNA helicase from the hyperthermophilic archaeon Sulfolobus shibatae].

A DNA helicase from the hyperthermophilic archaeon Sulfolobus shibatae has been purified to homogeneity by column chromatography on Q Seqharose, phosphocellulose P11, heparin agarose, Superdex 200 and phenyl Superose. The purified enzyme shows DNA-stimulated ATPase activity. The molecular mass of the enzyme is approximately 63 kD. The S. shibatae DNA helcase is capable of unwinding a 70 bp duplex DNA flanked by unpaired single-stranded tails at both ends. The helicase activity requires Mg2+ and hydrolysis of ATP, and is inhibited by NaCl at concentrations greater than 200 mmol/L. It has an optimal pH of 6.7. The enzyme is active at temperatures between 40 and 80 degrees C, and the activity peaks at 70 degrees C. The S. shibatae DNA helicase is the first native DNA helicase to be isolated from archaea.

Adenosine Triphosphatases↗
PubMed2001

[Synthesis and biological activities of new 5-HT2A selective ligands--N-substituted-piperidinyl-4-phenylthioether and sulfone derivatives].

AIM: A series of 4-piperidinylthioether and sulfone derivatives of 4-[1-hydroxy-1-(2,3-dimethoxyphenyl) methyl]-N-2-(4-fluorophenylethyl) piperidine (MDL 100907) were synthesized in order to find new 5-HT2A selective ligands. METHODS: Title compounds 2a-2c were synthesized from 2, 3-dimethoxythiophenol and tested for their affinities to 5-HT2A, 5-HT2C, 5-HT6 and 5-HT7 receptors and some other nervous transmitter receptors in vitro. RESULTS: Compounds 2a-2c are new compounds. The results of the binding assay demonstrated that they have relatively high selectivity for 5-HT2A receptor in vitro. CONCLUSION: Some sulfur containing analogues of MDL 100907 showed selective affinity to 5-HT2A receptor and are worth further study.

Animals↗
PubMed2001

Systemic administration of naked DNA: gene transfer to skeletal muscle.

Skeletal muscle is a promising target tissue for the gene therapy of both muscle and non-muscle disorders. Gene transfer into muscle tissue can produce a variety of physiologically active proteins and may ultimately be applied to the treatment of many diseases. A variety of methods have been studied to transfer genes into skeletal muscle, including viral and non-viral vectors. In this review, we discuss recent developments in the non-viral delivery of genes to muscles.

Animals↗
PubMed2000

[Relationship between hot spot mutation in hepatitis B virus basic core promotor and HBeAg status].

OBJECTIVE: This paper was to study the influence of hot spot mutation in hepatitis B virus (HBV) basic core promotor (BCP) (nt1762 and nt1764) on HBeAg status of asymptomatic HBV carriers. METHODS: Mismatched PCR was used to amplify the fragment of HBVBCP and the fragments were analysed by restrict enzyme assay. Ninety cases of HBV infection were tested for hot spot mutations in HBVBCP. RESULTS: Twenty-six (43.3%) of 60 asymptomatic HBV carriers with HBeAg negative were found to have hot spot mutations in HBVBCP, among which 20 cases were accompanied by the mutation of nt 1896 in HBV Pre-C region. Hot-spot mutation in HBVBCP, however, occurred only in 3(10%) of 30 asymptomatic HBV carriers with HBeAg positive. For further investigation the HBVBCP hot spot mutations in asymptomatic HBV carriers without mutation of HBV Pre-C region were studied. Six(31.6%) of 19 asymptomatic HBV carriers with HBeAg negative were found to have hot spot mutation in HBVBCP. Two(7.1%) of 28 asymptomatic HBV carriers with HBeAg positive had hot spot mutations in HBVBCP, and there was a statistically significant difference between two groups. CONCLUSIONS: Hot spot mutations in HBVBCP is common in the HBV carriers with HBeAg negative and usually accompanies with nt1896 mutation of HBV Pre-C region. It is possible that Hot spot mutation in HBVBCP is a new reason of HBeAg negative HBV infection.

Adult↗
PubMed2000

Adsorption/aggregation of surfactants and their mixtures at solid-liquid interfaces.

Adsorption of surfactants and polymers at solid-liquid interfaces is used widely to modify interfacial properties in a variety of industrial processes such as flotation, ceramic processing, flocculation/dispersion, personal care product formulation and enhanced oil recovery. The behavior of surfactants and polymers at interfaces is determined by a number of forces, including electrostatic attraction, covalent bonding, hydrogen bonding, hydrophobic bonding, and solvation and desolvation of various species. The extent and type of the forces involved varies depending on the adsorbate and the adsorbent, and also the composition and other characteristics of the solvent and dissolved components in it. The influence of such forces on the adsorption behavior is reviewed here from a thermodynamics point of view. The experimental results from microcalorimetric and spectroscopic studies of adsorbed layers of different surfactant and polymer systems at solid-liquid interfaces are also presented. Calorimetric data from the adsorption of an anionic surfactant, sodium octylbenzenesulfonate, and a non-ionic surfactant, dodecyloxyheptaethoxyethylalcohol, and their mixtures on alumina, yielded important thermodynamic information. It was found that the adsorption of anionic surfactants alone on alumina was initially highly exothermic due to the electrostatic interaction with the substrate. Further adsorption leading to a solloid (hemimicelle) formation is proposed to be mainly an entropy-driven process. The entropy effect was found to be more pronounced for the adsorption of anionic-non-ionic surfactant mixtures than for the anionic surfactant alone. Fluorescence studies using a pyrene probe on an adsorbed surfactant and polymer layers, along with electron spin resonance (ESR) spectroscopy, reveal the role of surface aggregation and the conformation of the adsorbed molecules in controlling the dispersion and wettability of the system.

Journal Article↗
PubMed2000

Modulation of circulating leptin levels by its soluble receptor.

Leptin is an adipocyte-derived hormone with potent weight reducing effects. Genetically obese rodents with mutations of leptin or the leptin receptor are defective in leptin signaling and develop morbid obesity and diabetes. Interestingly, the levels of both leptin mRNA and protein are increased by up to 20-fold in these animals, suggesting the existence of a feedback mechanism controlling the amount of leptin in circulation. In this report, we attempted to determine whether the up-regulation of circulating leptin in Zucker Diabetic Fatty rats, which are nonresponsive to leptin due to a receptor point mutation, is entirely due to increased expression of leptin. We demonstrate that the high level of circulating leptin in these rats is attributable to at least two factors: increased leptin expression by the adipose tissue and delayed clearance of leptin from circulation due to binding to its soluble receptor. The latter conclusion was supported by three lines of evidence: 1) The soluble leptin receptor is up-regulated by about 20-fold in Zucker Diabetic Fatty rats; 2) Adenovirus-mediated overexpression of the soluble leptin receptor results in a similar -fold increase of circulating leptin; 3) In ob/ob mice, which have no endogenous leptin, exogenously administered leptin reaches a higher level when the soluble leptin receptor is overexpressed. The weight-reducing effect of leptin is enhanced in C57Bl/6 ob/ob mice with overexpression of the soluble leptin receptor. Soluble leptin receptor may be a significant factor determining the amount of total leptin in circulation.

Animals↗
PubMed2000

Activation of the p21WAF1/CIP1 promoter independent of p53 by the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) through the Sp1 sites.

Suberoylanilide hydroxamic acid (SAHA) is a novel histone deacetylase inhibitor with high potency in inducing differentiation of cultured murine erythroleukemia cells. We have recently demonstrated that SAHA induces cell cycle arrest and apoptosis in human breast cancer cells, accompanied by up-regulation of the cyclin-dependent kinase inhibitor, p21WAF1/CIP1, via a p53-independent mechanism. In this study, we used p21 gene expression as a model system to elucidate the molecular mechanism(s) underlying SAHA-mediated gene activation. Treatment of human breast cancer cell line MCF7 cells with SAHA induced p21 mRNA as a consequence of an immediate-early gene activation. Moreover, SAHA activated the p21 promoter primarily through two Spl sites located at -82 and -69 relative to the transcription start site. Furthermore, Sp1 and Sp3 proteins were the major factors binding to the Spl site of the p21 promoter. However, SAHA did not alter their DNA binding activities, suggesting that SAHA mediates p21 promoter activity by a mechanism other than altering the DNA binding activities of Sp1 and Sp3. Further studies using the GAL4 luciferase assay system demonstrated that both GAL4-Sp1 and GAL4-Sp3 fusion proteins supported SAHA-mediated gene activation from a promoter driven by five GAL4 DNA binding sites, and that GAL4-Sp3 fusion protein was suppressive in the absence of SAHA treatment. Collectively, our results suggest that SAHA activates the p21 promoter through the Spl sites, and that both Spl and Sp3 proteins can mediate SAHA-induced gene activation.

Binding Sites↗
PubMed2000

Molecular characterization of a novel intracellular hyaluronan-binding protein.

Hyaluronan has well defined functions in extracellular matrices and at the surface of cells. However, several studies have now shown that significant pools of hyaluronan are also present intracellularly, but its function therein is unknown. One avenue of investigation that may assist in defining the function of intracellular hyaluronan is to identify intracellular hyaluronan-binding proteins. In previous studies we identified CDC37, a cell cycle regulatory protein, using a monoclonal antibody that recognizes a novel group of hyaluronan-binding proteins. In this study, we have identified a second hyaluronan-binding protein with this antibody and characterized its properties. This protein, which we have termed IHABP4, was also found to be an intracellular and a specific hyaluronan-binding protein, containing several hyaluronan-binding motifs: (R/K)[X(7)](R/K) (where R/K denotes arginine or lysine and X denotes non-acidic amino acids). Furthermore, we have determined the gene organization of IHABP4 and cloned cDNAs for the chick, mouse, and human homologs. Comparison of the deduced chick, mouse, and human protein sequences showed that the hyaluronan-binding motifs, (R/K)[X(7)](R/K), in these sequences are conserved; both chick and mouse IHABP4 were shown directly to bind hyaluronan. Biochemical fractionation and immunofluorescent localization of epitope-tagged IHABP4 indicated that it is mainly present in the cytoplasm. These data support the possibility that intracellular hyaluronan and its binding proteins may play important roles in cell behavior.

Amino Acid Sequence↗