Biomedical subjects

Y He

Publications and source records attributed to Y He.

At least 109 records · Page 6Linked to original sources

PubMed2001

[A study of millimeter wave's clinical and immunological effects on oral lichen planus patients].

OBJECTIVE: The aim of this study is to observe clinical effects of the millimeter wave on oral lichen planus (OLP) and its immune mechanisms. METHODS: 30 patients with OLP were randomized into the millimeter wave group and the control group. 15 patients in the millimeter wave group were treated with millimeter wave (7.1 mm, 43 GHz, 10 mW/cm2) radiation, while the other 15 patients in the control group were just given soothing treatment. Either before or after the therapy procedure, the clinical manifestations and the T-cell sub-grouping in the peripheral circulation of each patient were double-blindly evaluated. RESULTS: The pain-soothing effect in the patients treated with millimeter wave was much more obvious than that of the control group (P < 0.01). The peripheral blood CD8+ percent of millimeter wave group decreased greatly (P < 0.05), while no obvious CD8+ change was observed in the control group (P > 0.05). The millimeter wave group's CD4+/CD8+ improvement was also much more obvious than that of the control group (P < 0.05), and its CD4+/CD8+ ratio was completely recovered to the normal level. CONCLUSION: Millimeter wave can effectively relieve OLP patients' pain, and can regulate OLP patients' cellular immune condition. Millimeter wave might provide a new treatment method for OLP.

Adult↗

PubMed2001

[The examination of DNA repair capacity in the patients with oral precancerous lesion].

OBJECTIVE: The occurrence of oral precancerous lesion is related with not only carcinogenic environmental factors but also some self-regulating mechanisms. The genetic heredity factors determine individual's DNA repair capacity. The study is attempted to investigate the change of DNA repair capacity of the patients with the precancerous lesion. METHODS: The study is conducted in 16 pairs of oral precancerous lesion and normal controls by using host cell reactivation assay, while some dangerous factors such as smoking, alcohol intaking and family history of cancers are also recorded. RESULTS: The host cell reactivation in the patients with precancerous lesion is lower than that of normal controls (P < 0.05) and is shown to be an independent risk factor in the occurrence of oral precancerous lesion (OR: 3.25 95% CI = 1.01-10.49). CONCLUSION: The host cell reactivation is likely to be a helpful indicator for predict prognosis of cancer for the individuals with highly genetic sensitivity to cancer.

DNA Repair↗

PubMed2001

[The influence of palatoplasty and tympanotomy on middle ear function in cleft palate patients].

OBJECTIVE: The aim of this study is to explore the influence of palatoplasty and tympanotomy on middle ear function or hearing condition in cleft palate patients. METHODS: A total of 22 ears with otitis media with effusion in cleft palate patients were inserted with PE tubes, and Pre- and post-operative hearing level and middle ear function in these patients were tested and compared respectively, in order to demonstrate the action of tympanotomy and PE insertion on hearing and middle ear function. Another 38 patients with cleft palate were operated in their early age with the proper operation method, and pre- and post-operative middle ear function were examined and compared to show the influence of the operation on the middle ear function. RESULTS: PE Tube insertion and tympanotomy changed the pressure condition of middle ear cavity and raised the hearing level about 17 dB in the middle-ear-diseased cleft palate patients, and patients with palatoplasty did not show obvious changes in middle ear function in the short-term trail. CONCLUSION: Early and active tympanotomy do help in improving the function of the middle ear, and it is suggested to improve patients' hearing and middle ear function as early as possible. Palatoplasty did not affect the function of middle ear.

Cleft Palate↗

PubMed2001

[The influence of the hamulotome and interplatal incision on the middle ear function].

OBJECTIVE: The aim of this study is to explore the effect of hamulotome on the eustachian tube function and verify the function of the tensor veli palatili muscle on eustachian tube. METHODS: Single-sided hamulotome were carried out in the rabbits under the direct visual. And the middle ear cavity mucosa of the rabbits was collected at different intervals and dyed with PAS and PH to observe the middle ear changes under microscope. RESULTS: Middle ear function changed obviously after the hamulotome, with increase in globular cells, submucosal edema and inflammatory cells. And mucin was not found in several cavities. CONCLUSION: Hamulotome do affect on the middle ear function and should not be damaged in order to protect the middle ear function in some patients.

Animals↗

PubMed2001

[The study of a HPRT locus-specific transgenic method based on FLP recombinase mediated cassette exchange].

Exchange plasmid pF-HPRT-F3 and Flp expression plasmid pCMV-Flp were constructed and then introduced using electroporation system into F18 ES cell line, which have an exchange cassette F-Neo-F3 at HPRT locus. After HAT selection, HAT resistant clones were obtained. Then G418 sensitivity test and Southern blotting were carried out to screen RMCE recombinants. The results indicated that RMCE had taken place in three of 12 HAT resistant clones. The frequency is 25%. The result demonstrates that it is realizable to introduce transgene to HPRT locus by using Flp recombinase mediated cassette exchange reaction.

Animals↗

PubMed2001

[Synthesis and activities of 4-deoxy-4 beta-arylmehtylene sulfonylamido-4'-demethylpodophyllotoxins].

AIM: To find new anticancer drug based on the structure of podophyllotoxin. METHODS AND RESULTS: 4-Deoxy-4-beta-arylmethylenesulfonylamido-4'- demethylpodophyllotoxins were (1-15) synthesized and their antitumour activities against KB cells and L1210 leukemia cells were tested. CONCLUSION: These compounds are new compounds. Among them, compounds 2, 3, 8, 9, 11 and 12 showed antitumour activities. When halides exist on the aryl ring of substituted sulfonyl group, the corresponding compound has relatively higher activities. The stereo factor is important for the activities.

Animals↗

PubMed2001

[Long-term immunogenicity and immunologic priming of animals to pulsed controlled-release system for tetanus toxoid vaccine delivery].

AIM: To evaluate the immunogenicity of tetanus toxoid (TT) encapsulated in biodegradable polymer microspheres composed of polylactide (PLA). METHODS: The antibody levels elicited by microsphere formulations in mice for 1 year were examined, the anamnestic responses to a low dose booster 1 year after priming were also examined. RESULTS: Microsphere formulations made from PLA were characterized by pulse controlled-release models, differing in polymer molecular weight, protein loading and particle size of the microspheres. Microsphere formulations elicited significantly higher IgG antibody levels than a single injection of soluble TT. The antibody levels elicited by microsphere formulations were similar to those elicited by three doses of soluble TT. CONCLUSION: A single-dose tetanus toxoid based on pulsed release from biodegradable and biocompatible polymer microspheres has been developed. The formulations showed great benefits and pharmaceutical application.

Animals↗

PubMed2001

[Comparison between human sperm zona-free hamster ovum penetration assay and in-vitro fertilization].

OBJECTIVE: The research question was whether the result of human sperm zona-free hamsterovum penetration assay (SPA) could serve as an indicator for in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). METHODS: The semen samples of 22 male partners in couples with infertile marriage were assessed for their fertilizing capacity by SPA. The fertilization rate of SPA was compared with that of IVF. RESULTS: The fertilization rates of SPA and IVF were 38.6% +/- 23.5% and 53.5% +/- 28.4% respectively, and a significant correlation between SPA and IVF was observed (rs = 0.7045). CONCLUSION: The result of SPA may be used as a reference indicator for assisting fertilization, IVF or ICSI.

Animals↗

PubMed2000

Structure of the bacteriophage phi29 DNA packaging motor.

Motors generating mechanical force, powered by the hydrolysis of ATP, translocate double-stranded DNA into preformed capsids (proheads) of bacterial viruses and certain animal viruses. Here we describe the motor that packages the double-stranded DNA of the Bacillus subtilis bacteriophage phi29 into a precursor capsid. We determined the structure of the head-tail connector--the central component of the phi29 DNA packaging motor--to 3.2 A resolution by means of X-ray crystallography. We then fitted the connector into the electron densities of the prohead and of the partially packaged prohead as determined using cryo-electron microscopy and image reconstruction analysis. Our results suggest that the prohead plus dodecameric connector, prohead RNA, viral ATPase and DNA comprise a rotary motor with the head-prohead RNA-ATPase complex acting as a stator, the DNA acting as a spindle, and the connector as a ball-race. The helical nature of the DNA converts the rotary action of the connector into translation of the DNA.

Adenosine Triphosphatases↗

PubMed2000

Cerium and lanthanum promote floral initiation and reproductive growth of Arabidopsis thaliana.

The effects of cerium and lanthanum on the vegetative growth, floral initiation and reproductive growth of Arabidopsis thaliana were studied. Addition of cerium nitrate (0.5-10 µM) or lanthanum nitrate (0.5-50 µM) to the culture medium significantly increased the lengths of primary roots, but had no significant effects on the number of rosette leaves produced per plant, plant heights and dry weights during the vegetative growth stage (17 days after seed germination). The percentage of plants bolted was significantly increased with the addition of 0.5-10.0 µM cerium nitrate or lanthanum nitrate. The combination of 0.5 µM cerium nitrate and 0.5 µM lanthanum nitrate was found to be most effective on the induction of floral initiation. The height, dry weight and average number of flower numbers of 35-day-old plants growing in media containing cerium nitrate or/and lanthanum nitrate (0.5-10.0 µM) were found to be significantly higher than those in the control medium. The endogenous levels of cytokinins (zeatin riboside, dihydrozeatin riboside and isopentenyl adenosine) and carbohydrates (sucrose, glucose and fructose) in leaf and root tissues of plants growing in the medium supplemented with 0.5 µM cerium nitrate and 0.5 µM lanthanum nitrate were not significantly different from those of plants in the control medium. Application of 0.5 µM cerium nitrate and 0.5 µM lanthanum nitrate enhanced the effects of 10(-6) M IPA on root growth, plant height and flowering. The role of cerium and lanthanum in promoting floral initiation and reproductive growth and the possibility of developing non-hormonal flowering promoting agents are discussed.

Journal Article↗

PubMed2000

Integrated electroosmotically-driven on-line sample purification system for nanoliter DNA sequencing by capillary electrophoresis.

An integrated on-line system is developed for DNA sequencing at the nanoliter scale. The technique involves the use of a nanoreactor for small-volume cycle-sequencing reaction, capillary zone electrophoresis (CZE) for purification of the sequencing fragments, and capillary gel electrophoresis (CGE) for separation of the purified DNA fragments. The nanoreactor and CZE are integrated into one capillary, where a 100-nl dye-labeled terminator cycle-sequencing reaction is carried out followed by CZE to separate excess dye-labeled terminators from the sequencing fragments. On-line electrokinetic injection of the purified DNA fragments into the CGE system is accomplished at a small-volume tee connector by which the CZE capillary is interfaced to the CGE system. The utility of the system is demonstrated in sequencing nanoliter volumes of single-stranded DNA (M13mp18) and double-stranded DNA (pGEM). The use of voltage to drive both CZE and CGE makes it feasible for automation and future adaptation of the whole system to a microchip.

Base Sequence↗

PubMed2000

Proximal promoter of the surfactant protein D gene: regulatory roles of AP-1, forkhead box, and GT box binding proteins.

Surfactant protein D (SP-D) plays roles in pulmonary host defense and surfactant homeostasis and is increased following lung injury. Because AP-1 proteins regulate cellular responses to diverse environmental stimuli, we hypothesized that the conserved AP-1 motif (at -109) and flanking sequences in the human SP-D promoter contribute to the regulation of SP-D expression. The AP-1 sequence specifically bound to fra-1, junD, and junB in H441 lung adenocarcinoma nuclear extracts. Mutagenesis of the AP-1 motif in a chloramphenicol acetyltransferase reporter construct containing 285 base pairs of upstream sequence nearly abolished promoter activity, and co-transfection of junD significantly increased wild type but not mutant promoter activity. The sequence immediately downstream of the AP-1 element contained a binding site for HNF-3 (FOXA), and simultaneous mutation of this site (fox-d) and an upstream FoxA binding site (-277, fox-u) caused a 4-fold reduction in chloramphenicol acetyltransferase activity. Immediately upstream of the AP-1-binding site, we identified a GT box-containing positive regulatory element. Despite finding regions of limited homology to the thyroid transcription factor 1-binding site, SP-D promoter activity did not require thyroid transcription factor 1. Thus, transcriptional regulation of SP-D gene expression involves complex interactions with ubiquitous and lineage-dependent factors consistent with more generalized roles in innate immunity.

Amino Acid Motifs↗

PubMed2000

Phosphorylation of serine 43 is not required for inhibition of c-Raf kinase by the cAMP-dependent protein kinase.

The activity of the serine/threonine kinase c-Raf (Raf) is inhibited by increased intracellular cAMP. This is believed to require phosphorylation with the cAMP-dependent protein kinase (PKA), although the mechanism by which PKA inhibits Raf is controversial. We investigated the requirement for PKA phosphorylation using Raf mutants expressed in HEK293 or NIH 3T3 cells. Phosphopeptide mapping of (32)P-labeled Raf (WT) or a mutant lacking a putative PKA phosphorylation site (serine to alanine, S43A) confirmed that serine 43 (Ser(43)) was the major cAMP (forskolin)-stimulated phosphorylation site in vivo. Interestingly, the EGF-stimulated Raf kinase activity of the S43A mutant was inhibited by forskolin equivalently to that of the WT Raf. Forskolin also inhibited the activation of an N-terminal deletion mutant Delta5-50 Raf completely lacking this phosphorylation site. Although WT Raf was phosphorylated by PKA, phosphorylation did not inhibit Raf catalytic activity in vitro, nor did forskolin treatment inhibit the activity of an N-terminally truncated Raf protein (Raf 22W) or a full-length Raf protein (Raf-CAAX) expressed in NIH 3T3 cells. In contrast, forskolin inhibited the EGF-dependent activation of a Raf isoform (B-Raf), lacking an analogous phosphorylation site to Ser(43). Thus, these results demonstrate that PKA exerts its inhibitory effects independently of direct Raf phosphorylation and suggests instead that PKA prevents an event required for the EGF-dependent activation of Raf.

Catalytic Domain↗

PubMed2000

Identification of E2F-3B, an alternative form of E2F-3 lacking a conserved N-terminal region.

We have identified a novel form of the full-length E2F-3 protein that we term E2F-3B. In contrast to full-length E2F-3, which is expressed only at the G1/S boundary, E2F-3B is detected throughout the cell cycle with peak levels in GO where it is associated with Rb. Transfection and in vitro translation experiments demonstrate that a protein identical to E2F-3B in size and iso-electric point is produced from the E2F-3 mRNA via the use of an alternative translational start site. This alternative initiation codon was mapped by mutagenesis to codon 102, an ACG codon. Mutation of the ACG codon at position 102 abolished E2F-3B expression, whereas the conversion of ACG 102 to a consensus ATG led to the expression of a protein indistinguishable from E2F-3B. Given these results, E2F-3B is missing 101 N-terminal amino acids relative to full-length E2F-3. This region includes a moderately conserved sequence of unknown function that is present only in the growth-promoting E2F family members, including E2F-1, 2 and full-length E2F-3. These observations make E2F-3B the first example of an E2F gene giving rise to two different protein species and also suggest that E2F-3 and E2F-3B may have opposing roles in cell cycle control.

3T3 Cells↗

PubMed2000

[Analysis of prognosis of severe hepatitis].

OBJECTIVE: To study the effect of prognosis of severe hepatitis. METHODS: The prognosis factors of 286 patients with severe hepatitis were studied with monofactor analysis(chi 2 test, t test) and polyfactors analysis(logistic regressive analysis). RESULTS: The factors affected the prognosis of the patients were age, therapeutics, biochemistry data and complications. CONCLUSION: To decrease the mortality of the patients with severe hepatitis, we should adopt rational therapeutics and prevent complications in clinical practice.

Adult↗

PubMed2000

Measurements of N2O and CH4 from the aerated composting of food waste.

Emissions of N2O and CH4 from an aerated composting system were investigated using small-scale simulated reactors. The results show relatively high emissions of N2O at the beginning of composting, in proportion to the application amount of food waste. After 2 days, the N2O emission decreased to 0.53 ppmv on average, near to the background level in the atmosphere (0.45 ppmv). The addition of composted cattle manure increased N2O emissions not only at the beginning of composting, but also during the later period and resulted in two peak emission curves. Good correlation was observed between the N2O concentration at the air outlet and NO2- concentration in waste, suggesting a generation pathway for N2O from NO2- to N2O. Methane was only detected in treatments containing composted cattle manure. The high emission of methane illustrates the involvement of anoxic/anaerobic microorganisms with the addition of composted manure. The result suggests the existence of anoxic or anaerobic microsite inside the waste particles even though ventilation was employed during the composting process.

Animals↗

PubMed2000

The Absolute Configuration and Asymmetric Total Synthesis of the CP Molecules (CP-263,114 and CP-225,917, Phomoidrides B and A) We thank Drs. D. H. Huang, G. Siuzdak, and R. Chadha for assistance with NMR spectroscopy, mass spectrometry, and X-ray crystallography, respectively. This work was financially supported by the National Institutes of Health (USA), The Skaggs Institute for Chemical Biology, doctoral fellowships from the National Science Foundation (P.S.B.) and Boehringer Ingelheim (Y.H.), and grants from Array Biopharma, Boehringer Ingelheim, Schering Plough, Pfizer, Glaxo, Merck, Hoffmann-La Roche, DuPont, and Abbott Laboratories.

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Journal Article↗

PubMed2000

Constitutive activation of Stat3 signaling abrogates apoptosis in squamous cell carcinogenesis in vivo.

Field cancerization predisposes the upper aerodigestive tract mucosa to the formation of multiple primary tumors, when exposed to environmental carcinogens. Up-regulation of epidermal growth factor receptor occurs early in squamous cell carcinogenesis and is critical for the loss of growth control in a variety of human cancers, including head and neck squamous cell carcinomas. In these tumor cells in culture, epidermal growth factor receptor stimulation initiates signaling via persistent activation of selective STAT proteins. To determine the timing of Stat3 activation in head and neck carcinogenesis, we studied the expression and constitutive activation of Stat3 in tumors and normal mucosa from patients with head and neck cancer compared with mucosa from controls without cancer. Stat3 was up-regulated and constitutively activated in both primary human head and neck tumors as well as in normal mucosa from these cancer patients compared with control normal mucosa from patients without cancer. In vivo liposome-mediated gene therapy with a Stat3 antisense plasmid efficiently inhibited Stat3 activation, increased tumor cell apoptosis, and decreased Bcl-x(L) expression in a head and neck xenograft model. These findings provide evidence that constitutively activated Stat3 is an early event in head and neck carcinogenesis that contributes to the loss of growth control by an anti-apoptotic mechanism.

Animals↗