Search PubMed⌕ Search

Biomedical subjects

Q Xie

Publications and source records attributed to Q Xie.

At least 109 records · Page 6Linked to original sources
PubMed1997

Central distribution of sensory fibers in the facial nerve: an anatomical and immunohistochemical study.

Wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) injection into the facial nerve of the cat resulted in retrograde labeling in the geniculate and jugular ganglia ipsilaterally. Labeled fibers were found to enter into the brain stem through the intermediate and vagal nerves. These fibers ascended or descended into the dorsal portion of the spinal trigeminal tract and were distributed to the principal sensory nucleus of the trigeminal nerve, marginal layer of the interpolar part of the spinal trigeminal nucleus, nucleus of the solitary tract and ventrolateral portion of the cuneate nucleus. It was of particular interest in the present study that the intensive labeling was present in the medial portion of laminae I-IV of the upper cervical spinal cord. The immunohistochemical study revealed a lot of substance P-immunoreactive neurons in the geniculate and jugular ganglia, and heavy accumulation of immunoreactive fibers in laminae I-II of the upper cervical spinal cord.

Afferent Pathways↗
PubMed1997

Association of residual ridge resorption with systemic factors in home-living elderly subjects.

Residual ridge resorption after loss of teeth is a multifactorial oral problem. To examine the association of residual ridge resorption with systemic factors, a cross-sectional study was made of 177 edentulous subjects (43 men and 134 women) aged 76, 81, and 86 years. Resorption in the mandibular and maxillary residual ridges was assessed from panoramic radiographs. The effects on residual ridge resorption of the age, gender, smoking, alcohol intake, body mass index, functioning in daily living, and certain systemic diseases of the subjects were investigated. After adjustment for age and duration of edentulousness, the elderly women had a greater amount of reduction in the mandibular residual ridge than the men (P < 0.001). When the resorption was classified into slight or moderate and severe resorptions, the elderly with asthma were at high risk of severe reduction in the edentulous mandible (odds ratio, 6.0; 95% confidence interval (CI), 1.3-28.2); the elderly women were at high risk of severe resorption in the edentulous mandible, with an odds ratio of 4.5 (95% CI, 1.2-17.1); an inverse association was found between alcohol intake and severe resorption in the edentulous maxilla (odds ratio, 0.4; 95% CI, 0.2-0.9). This study suggests that asthma due to corticosteroid treatment is to be considered a risk indicator for severe resorption of the edentulous mandible, alcohol intake in the elderly may be related to a lesser degree of resorption of the edentulous maxilla. Female gender is confirmed as a major factor resulting in mandibular atrophy.

Activities of Daily Living↗
PubMed1997

Oral status and prosthetic factors related to residual ridge resorption in elderly subjects.

Our earlier studies on edentulous elderly subjects have shown associations of severe resorption in the mandibular residual ridge with female gender and systemic diseases. The aim of this study was to examine whether other factors also were related to residual ridge resorption (RRR). Among 177 edentulous elderly subjects effects on RRR were investigated with regard to history of edentulousness and denture-wearing, the condition of the dentures and soft tissues, dental status of the opposing jaw, and oral hygiene habits. No significant association was found between degree of resorption and duration of edentulousness in either the mandible or the maxilla. RRR was related to denture quality (P < 0.05); however, severe resorption was not. In the maxilla previous use of removable partial dentures was a factor contributing to the resorption (odds ratio (OR), 2.4); flabby ridge was related to the severity of the resorption (OR, 2.4). This study showed local factors related to RRR more often in the maxilla than in the mandible, thus suggesting that severe resorption in the mandible is influenced more by systemic factors than by those investigated in this study.

Aged↗
PubMed1997

Quantitative assessment of vertical heights of maxillary and mandibular bones in panoramic radiographs of elderly dentate and edentulous subjects.

The clinical applicability of vertical measurements of the mandible and maxilla in panoramic radiographs was studied by assessing the variety of vertical heights among 91 elderly dentate subjects. Measurements in each jaw and calculations of a maxillary ratio were made at five sites. Variations in measurements of the dentate subjects were small: 9-11% for vertical measurements in the mandible, 6-11% for vertical measurements in the maxilla, and 8-10% for the maxillary ratios. These findings suggest that it is possible quantitatively to assess heights of the mandibular and maxillary bones in panoramic radiographs. Reductions in the edentulous jaws were assessed by comparing the heights of jaws of elderly dentate subjects with those measured in 177 elderly edentulous subjects. Significant differences in heights of the mandibular body and maxilla were found between the dentate and the edentulous (P < 0.001). Edentulous women had greater values for percentage reduction in the mandibles than did the men (P < 0.01; P < 0.001 in various locations).

Aged↗
PubMed1997

[Gene frequency of HPA among Hunan population of Han nationality].

We used allele specific primer PCR (ASP-PCR) method to detect the genotype of five major HPA systems among Hunan population of Han nationality. The results showed: The gene frequency of PLA1 was 81.00% and 85.87% for Kob, 71.00% for Baka, 91.00% for Pena, 90.67% for Brb which provided the basis for further clinical application of HPA.

Adult↗
PubMed1997

[Antiallergic effects of tranilast in rats and guinea pigs].

Tranilast is an anti-allergic drug. In this study, we made a comparision between the Tranilast synthized by School of Pharmacy WCUMS using new technical and the Tranilast produced by Kissei pharmaceutical Co. LTD, Japan on their antiallergic effects. We found that the two tranilasts had the same antiallergic effects: (1) they inhibit the passive cutaneous anaphylaxis in sensitized rats with the dose of 100, 200 mg/kg(P < 0.01); (2) they inhibit degranulation of mast cells in sensitized rats (10(-5) and 10(-4) mol/L) (P < 0.05); (3) they inhibit schultz-Dale response in sensitized guinea pigs (10(-3) and 10(-4) (mol/L); (4) the inhibit SRS-A release from the lung of sensitized guinea pigs(10(-3), 10(-4) and 10(-5) mol/L) (P < 0.05); and (5) they inhibit the contraction of ileum of normal guinea pigs induced by SRS-A(10(-4) and 10(-3) mol/L).

Animals↗
PubMed1997

[Optimum choice for the cultivation of CFU-GM in media buffered with HEPES].

The effects of media buffered with HEPES of different concentrations and different incubation periods on the proliferation and differentiation of CFU-GM were studied under the standard condition for culture. The results exhibited that when the incubation period prolonged, the pH values of culture system raised and the colony formation of CFU-GM decreased; the culture system added with proper HEPES buffer solution could maintain and increase the colony formation of CFU-GM, especially the culture system in which the pH value was not adjusted before the experiment. We also found that media buffered with HEPES could change the ratio of different colony types. This showed that media buffered with HEPES could not only stimulate the proliferation of CFU-GM, but also affect its differentiation. The results suggest that media buffered with HEPES are better than those without HEPES for the culture of hematopoietic progenitor cells, and the optimum concentration is 10-20 mmol.L-1.

Animals↗
PubMed1997

[Expression level of MDR1, and MRP in patients with malignant blood disease and its clinical significance].

RT-PCR method was used to detect the expression level of multi-drug resistance gene (MDR1) and multi-drug resistance associated protein (MRP) in patients with malignant blood disease, including 19 cases of acute leukemia and 6 cases of multiple myeloma. The results showed: expression level of MDR1 in patients with known clinical drug resistance elevated obviously and was significantly associated with clinical drug resistance (r = 0.612, P < 0.01), which indicated that expression of MDR1 was the main mechanism of clinical drug resistance. There is no obvious relationship between expression level of MDR1 and MRP (r = 0.035, P > 0.05).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Canine parvovirus capsid structure, analyzed at 2.9 A resolution.

The DNA-containing capsid of canine parvovirus (CPV) is analyzed following atomic refinement at 2.9 A resolution. The capsid contains 60 copies of the capsid protein related by icosahedral symmetry. The atomic model has been extended from the first residue (Gly37) of the unrefined 3.25 A structure towards the N terminus. The electron density shows that approximately 87% of the capsid proteins have N termini on the inside of the capsid, but for approximately 13%, the polypeptide starts on the outside and runs through one of the pores surrounding each 5-fold axis, explaining apparently conflicting antigenic data. Analysis of potential hydrogen bonds reveals approximately 50% more secondary structure than previously apparent. Most of the additional secondary structure are in the 71 and 221 residue-long loop insertions between beta-strands E and F and G and H, forming subunit-bridging sheets that likely add specificity to assembly interactions. Structural analysis of the extensive subunit interactions around the 3-fold axes shows that assembly is a multistep process with loops intertwining following initial contact. Estimated free energies of association suggest that the formation of 3 and 5-fold contacts likely takes precedence over 2-fold interactions. Energies for initial association into trimers or pentamers would be similar, but the intertwining of loops about the 3-fold axis adds an additional large activation barrier to dissociation. Analysis of the surfaces of the assembled capsid shows a surprising lack of basic amino acids that might have been expected to interact with the negatively charged phosphoribose backbone of the DNA. Instead, uncharged polar and van der Waal's interactions predominate in the packaging of single-stranded DNA into the capsid.

Amino Acid Sequence↗
PubMed1996

Stoichiometry of subunits and heme content of hemoglobin from the earthworm Lumbricus terrestris.

The extracellular hemoglobin (Hb) of the earthworm, Lumbricus terrestris, has four major O2-binding chains, a, b, c (forming a disulfide-linked trimer), and d ("monomer"). Additional structural chains, "linkers," are required for the assembly of the approximately 200-polypeptide molecule. The proportion of linker chains had been reported to be one-third of the total mass on the basis of densitometry of Coomassie Blue-stained SDS-gels. Reverse-phase high performance liquid chromatography (HPLC), however, gave 16.3% linkers on the basis of both 220-nm absorbance and amino acid analysis (Ownby, D. W., Zhu, H., Schneider, K., Beavis, R. C., Chait, B. C., and Riggs, A. F. (1993) J. Biol. Chem. 268, 13539-13547). The subunit proportions have now been redetermined by SDS capillary electrophoresis as a test of the HPLC results. The electrophoresis, monitored at 214 nm, avoided the use of Coomassie Blue and provided results identical with those obtained by HPLC. Capillary electrophoresis monitored at both 214 and 415 nm was used to show that linker chains do not bind heme. Heme content has been found to be 2.9% by determination of hemin, amino acid analysis and dry weight. Measurement of the rate of hemin loss from oxidized L. terrestris Hb shows that high rates of loss can account for values of heme content significantly below 2.9% (or 0.26% iron).

Animals↗
PubMed1996

Plant cells contain a novel member of the retinoblastoma family of growth regulatory proteins.

The product of the retinoblastoma susceptibility gene (Rb) controls the passage of mammalian cells through G1 phase. Animal virus oncoproteins interact with the Rb protein via an LXCXE motif and disrupt Rb-E2F complexes, driving cells into S-phase. Recently, we found that the RepA protein of a plant geminivirus contains an LXCXE motif that is essential for its function, a finding that predicts the existence of Rb-related proteins in plant cells. Here we report the isolation of a maize cDNA clone encoding a protein (ZmRb1) which, based on structural and functional studies, is closely related to the mammalian Rb family of growth regulatory proteins. ZmRb1 shows a high degree of amino acid conservation when compared with animal Rb members, particularly in the A/B 'pocket' domain, but ZmRb1 has a shorter N-terminal domain. ZmRb1 forms stable complexes with plant LXCXE-containing proteins, e.g. geminivirus RepA protein. Geminivirus DNA replication is reduced in plant cells transfected with plasmids encoding either ZmRb1 or human p130, a member of the Rb family. This suggests that ZmRb1 controls the G1/S transit in plant cells and is consistent with the fact that geminiviruses need an S-phase environment for DNA replication, as animal DNA tumor viruses do. Our results allow the extension of the Rb family of tumor suppressor proteins to plants and have implications on animal and plant strategies for cell growth control.

Amino Acid Sequence↗
PubMed1996

Molecular cloning of a novel allele of SMR1 which determines sulfometuron methyl resistance in Saccharomyces cerevisiae.

A different mutation (SMR1B) to SMR1-410 (ilv2), which determines resistance to sulfometuron methyl in Saccharomyces cerevisiae, was cloned by PCR. Sequence analysis indicated a C to T change at position 575 of the ILV2 coding sequence, which results in a proline transition to leucine at position 192. Similarly to SMR1-410, the SMR1B gene was confirmed as a convenient dominant selective marker for yeast transformation including industrial strains.

Alleles↗
PubMed1996

Contribution of interferon-gamma in protecting mice during pulmonary and disseminated infection with Cryptococcus neoformans.

In the present study, the role of interferon-gamma (IFN-gamma) in the host resistance against Cryptococcus neoformans was examined using a murine model of pulmonary and disseminated infection. In this model, mice were infected intratracheally with live yeast cells, and the histological changes in the lungs and the number of microorganisms in the lung and brain were compared in mice treated and untreated with anti-IFN-gamma monoclonal antibody (mAb) to define the contribution of endogenously synthesized IFN-gamma in the natural course of infection. Administration of this mAb reduced the accumulation of inflammatory cells in the alveolar septa, peribronchial and perivascular areas, and promoted the expansive growth of microorganisms in the alveoli and destruction of alveolar structure. The neutralization of endogenous IFN-gamma by mAb increased the number of microorganisms in the lung and brain, and significantly shortened the survival time of infected mice. On the other hand, administration of IFN-gamma decreased the number of microorganisms in these organs, and significantly extended their survival time. Considered together, our results suggest that endogenous IFN-gamma protects mice from infection with C. neoformans by inducing a cellular inflammatory response, potentiating the clearance of microorganism from the lungs and preventing its dissemination into the central nervous system.

Animals↗
PubMed1996

IL-12 protects mice against pulmonary and disseminated infection caused by Cryptococcus neoformans.

We examined the role of IL-12 in host resistance to Cryptococcus neoformans using a murine model of pulmonary and disseminated infection. In this model, mice were infected intratracheally with viable yeast cells. Mice untreated with IL-12 allowed an uncontrolled multiplication of yeast cells in the lung with infiltrations of few inflammatory cells, and a cryptococcal dissemination to the brain and meningitis by 3 weeks, resulting in death of all animals within 4-6 weeks. IL-12, when administered from the day of tracheal infection for 7 days, induced a marked infiltration of inflammatory cells, consisting mostly of mononuclear cells, and significantly reduced the number of viable yeast cells in the lung. The treatment suppressed brain dissemination, as shown by a marked reduction of yeast cells in the brain and prevention of meningitis. These effects resulted in a significant increase in the survival rate of infected mice. In contrast, late administration of IL-12 commencing on day 7 after instillation of yeast cells failed to protect the mice against infection with C. neoformans. In further experiments, early administration of IL-12 markedly induced interferon-gamma (IFN-gamma) mRNA in the lungs of infected mice, while no IFN-gamma mRNA was detected without this treatment. Our results indicate that IL-12 is effective when administered in the early period of pulmonary cryptococcal infection.

Animals↗
PubMed1996

Height of the residual ridge and radiographic appearance of bony structure in the jaws of clinically edentulous elderly people.

Alveolar atrophy and its relation to osteopenia of the mandible were studied in 124 edentulous 76-, and 81- and 86-year-old subjects (32 males and 92 females). Both variables were assessed visually from panoramic radiographs. Mandibular alveolar atrophy was found to be more severe in women (P < 0.001). No statistically significant differences were found between the three age-groups in mandibular alveolar atrophy, nor between the sexes or age-groups in maxillary alveolar atrophy. The structure of the mandibular bone was osteopenic in 38 patients (30.7%), a situation that was more frequent in women (P < 0.001). The relationship between the observed osteopenia and the severity of the mandibular alveolar atrophy in women was statistically significant (P < 0.05).

Age Factors↗
PubMed1996

Marek's disease virus (MDV) ICP4, pp38, and meq genes are involved in the maintenance of transformation of MDCC-MSB1 MDV-transformed lymphoblastoid cells.

An antisense strategy has been used to identify genes important for the maintenance of transformation of MDCC-MSB1 (MSB1) Marek's disease virus-transformed lymphoblastoid cells. Oligodeoxynucleotides antisense to the predicted translation initiation regions of ICP4 and pp38 mRNAs inhibited proliferation of MSB1 cells but not MDCC-CU91 (CU91) reticuloendotheliosis virus-transformed cells. Control oligodeoxynucleotides having the same base composition but a different sequence did not inhibit MSB1 cell proliferation. In addition, ICP4 and pp38 antisense oligodeoxynucleotides resulted in 77- and 100-fold reductions in colony formation by MSB1 cells in soft agar, respectively. To extend and corroborate these results, a novel system based on efficiently regulated expression of eukaryotic genes by a chimeric mammalian transactivator, LAP267 (S. B. Baim, M. A. Labow, A. J. Levine, and T. Shenk, Proc. Natl. Acad. Sci. USA 88:5072-5076, 1991), was used. MSB1-derived stably transfected cell lines in which RNA antisense to Marek's disease virus ICP4, pp38, or meq could be induced by treatment of the cells with isopropyl-beta-D-thiogalactopyranoside (IPTG) were constructed. Control cell lines in which expression of ICP4 sense or pUC19 sequences could be induced by IPTG were also constructed. Induction of the cell lines indicated that ICP4 antisense RNA, but not ICP4 sense RNA or pUC19 RNA, inhibited proliferation of MSB1 cells. Induction of ICP4, meq, or pp38 antisense RNAs, but not ICP4 sense or pUC19 RNAs, had a dramatic effect on relative colony formation by MSB1 cells in soft agar. These results indicate that ICP4, pp38, and Meq are all involved in the maintenance of transformation of MSB1 cells.

Animals↗
PubMed1996

Effect of head positioning in panoramic radiography on vertical measurements: an in vitro study.

OBJECTIVE: To assess whether it is possible to make accurate vertical measurements of the jaws from panoramic radiographs. METHODS: Five dry skulls were shifted 5 mm forwards and backwards and tilted 5 degrees up and down in the sagittal plane. Panoramic radiographs of each skull were obtained in nine different positions. In the maxilla, three reference lines were used and vertical measurements were made at the distal surfaces of the first premolar and first molar and in the midline. In the mandible, measurements were made at the distal surfaces of the first premolar and first molar, and at the mental foramen on both sides, and in the midline. The points and lines were marked manually and the radiographs were digitized, magnified and measured. RESULTS: Sagittal shifting and tilting had only a slight effect on measurements in the mandible. Sagittal tilting of the head had the greatest effect on all the measurements made from the line between the articular eminences to the alveolar crest, as well as measurements in the maxillary midline. CONCLUSIONS: The line between the articular eminences is unsuitable as a reference line for measurements of the tooth-bearing areas. A slight misalignment of the head does not significantly affect the vertical measurements in the mandible or of the posterior maxilla if the reference lines are in the same vertical plane as the teeth.

Analysis of Variance↗