Biomedical subjects

X Zhou

Publications and source records attributed to X Zhou.

At least 397 records · Page 22Linked to original sources

PubMed1999

[Construction of Streptococcus mutans surface protein antigen eukaryotic expression vector pcDNA3-PAc. II. Testified efficiency of repeated using glass fiber chromatographic column].

OBJECTIVE: To explore one method getting highly purified plasmid DNA and costing low. METHODS: According to principle of extraction and purification plasmid DNA of glass fiber chromatographic column, its operation sequence was improved so that disposable glass fiber chromatographic column could be used repeatedly. The concentration and purity of plasmid DNA obtained by 12 times repeated using glass fiber chromatographic column were determined by spectrophotometry. Moreover, Those plasmid DNA obtained were tested by restriction enzyme and agarose gel electrophoresis, Ligation in vitro and transformation test. RESULTS: 12 times repeated use of glass fiber chromatographic column made no significant difference to the concentration and purity of obtained plasmid DNA (P < 0.05), and plasmid DNA was completely digested by restriction enzyme. The digested fragments were well ligated together by the action of T4 DNA Ligase in ATP ligating buffer in vitro and ligated DNA was well transformed into E. coli. CONCLUSION: Repeated use glass fiber chromatographic column can obtain a lot of highly purified plasmid DNA and cost is low. Digestion, ligation and transformation of those plasmid DNA are not affected. The results may be significant in molecular cloning and study of gene vaccination.

Antigens, Surface↗

PubMed1999

[A primary study of relationship between proteolytic enzymes in dental plaque and deciduous caries].

OBJECTIVE: The purpose of this paper was to study the role of proteolytic enzymes in dental plaque in deciduous caries occurrence. METHODS: Fluorometry and spectrometry were used separately to determine the activities of leucine amino peptidase, dipeptidyl peptidase IV and trypsin-like proteinase in caries-positive and caries-free children. RESULTS: The activities of the three enzymes in dental plaque in different children were same (P > 0.05). CONCLUSION: The three enzymes may be not related to deciduous caries.

Child↗

PubMed1999

[Study of effects of six caries-preventive agents on enamel decalcification].

OBJECTIVE: To compare the influence of 6 caries-preventive agents containing fluoride and trace element on dental enamel decalcification and observe the relationship between enamel decalcification and time of early carious lesions. METHODS: 84 bovine teeth were selected and divided into 7 groups. Experimental groups were treated with SrF, SnF2, (NH4)2 MoO2F4, ZnF, LaF and NaF with the same [F-]concentration and deionised water respectively, then all the specimens formed artificial carious lesion in lactic acid gel. RESULTS: The [Ca2+] concentration of lactic acid gel showed a variety of enamel decalcification among specimens treated with fluoride agents after 48 hours, on the other hand, all the specimens presented a platform of enamel decalcification after 48 hours. SnF2 demonstrated the strongest inhibition on enamel decalcification, meanwhile, NaF has the minimum influence on it. CONCLUSION: The time of forming artificial carious lesion with acid etch is about 48 hours, moreover, caries-preventive agents containing fluoride and trace element are effectively able to inhibit enamel decalcification, and the potential mechanism is the interaction of fluoride and trace element.

Animals↗

PubMed1999

[Simultaneous determination of gibberellins A1 and A3 in foxtail millet seedlings by high performance liquid chromatography].

Gibberellin A1(GA1) and Gibberellin A3(GA3) in millet seedlings were simultaneously determined by HPLC on a Zorbax-ODS-C18 (4.6 mm x 250 mm, 10 microns) column, using a mobile phase consisting of V (0.02 mol/L phosphate buffer solution, pH 4.0):V(methanol) = 2.2:1, a flow rate of 0.8 mL/min and a UV detection at 210 nm. GA1 and GA3 were separated completely in 10 min. Correlation coefficients for linear equations were 0.9986 and 0.9978, recoveries were 102.54% and 99.59%, respectively. Two normal cultivars and their dwarf-mutants were determined by this method. The results showed that both GA1 and GA3 were discovered in foxtail millet seedling, and endogenous mass ratio of GA1 and GA3 in foxtail millet dwarf-mutants were significantly lower than those in normal cultivars, and the concentrations of endogenous GA1 and GA3 were important factors for plant-height.

English Abstract↗

PubMed1999

[Analysis of organic acids in human dental plaque by means of gas chromatography/mass spectrometry].

The purpose of this study was to investigate the composition of plaque fatty acids in the healthy population. The study was made on 10 volunteers over the age of 18 who were divided into three sub-groups (3-4 individuals). Neither subject exhibited clinical evidence of salivary gland disorder and any medication affecting salivary functions were not used. A sensitive GC/MS method with VG7070E mass spectrometer was developed in our study. The sample separation was carried out on a fused silica capillary column with OV-1. The column size was 23 m x 0.23 mm. The temperature program was as follows: from 40 degrees C to 120 degrees C fast, then from 120 degrees C to 240 degrees C at 6 degrees C/min. The results showed that there were 14 organic acids and isomers present in plaque. They were C12:0, C14:0, C15:0, C16:0, C16:1, C18:0, C18:1, C18:2, C20:0 and phenylacetic acid, phenylpropionic acid. The higher content of fatty acids in the sample were C16:0, C18:0, and C18:1. The aromatic acids were detected only in some samples. The odd-numbers fatty acids and aromatic acids were for the first time detected. The origin of organic acids in plaque is an ongoing area of research. Our data clearly identify the bacterial contribution to the organic acids of plaque matrix, which may have a special relationship with bacteria metabolism. The research will help us to understand fatty acids metabolism of dental plaque and to determine their role in the microbial homeostasis of dental plaque.

Adult↗

PubMed1999

[Research of experimental fistula stimuli vestibule evoked response].

OBJECTIVE: To investiqate a way of stimulation for experimental vestibul evoked response. The artificial fistula of right upper semicircular canal was made in 12 guineapig. METHOD: Using a fistula stimuli probe device designed specially. RESULT: We obtain a potential consisting of 3-4 positive waveforms. We called it the fistula stimuli vestibule evoked response (FsVeR). They had a coincide character. The response disappeared when the animal died. The cervical spinal section, orbital removal and facial nerve removal had little effects to FsVeR. When severe inner ear damage produced by Gentamycin injection, the potential disappeared. The potential disappeared but ABR were existed. When the upper semicircular canal and its nerve damage. The noise screen had a little affection to FsVeR. CONCLUSION: These results indicated that FsVeR was mainly originated from the vestivbule system. The development of this recording technique provides a new method and maybe has important value for vestibule experimental research work.

Acoustic Stimulation↗

PubMed1999

[Effects of combined treatment with flouride and 1,25-dihydroxyvitamin D3 on the histomorphometry and biomechanical properties of bone in ovariectomized rats].

OBJECTIVE: To evaluate the potential use of a combination of bone formation-promoting agents and a differentiation agent of osteoblast as a treatment for postmenopausal osteoporosis. METHODS: The effects of combined and separate administration of flouride-Ca (0.45 ng F- + 13.56 mg Ca2+)/(kg.d) and 1,25-dihydroxyvitamin D (135 pmol/d s.c.) on the histomorphometric parameters in the secondary spongiosa of proximal tibia and biomechanical properties of femoral midshaft in ovariectomized (OVX) rats were examined. RESULTS: Compared with OVX group, OVX + fluoride-Ca group (O + F) and OVX + Fluoride-Ca + 1,25-dihydroxyvitamin D(O + F + D) two kinds of treatment caused 42%, 91% more in %Tb Ar, 14%, 38% more in Tb Wi, 24%, 46% more in Tb N, 26%, 43% less in Tb Sp, 45%, 42% less in % E Pm, 30%, 60% more in Ob Pm respectively. W Wi in O + F treatment had no significant difference from OVX group but 15.2% in O + F + D treatment compared with sham group, MLT increased 16% in O + F group, had no difference from O + F + D. No significant alteration of mechanical strength at femoral midshaft in both O + F and O + F + D was found. There were significant difference in above changes of parameters except % Ob Pm. CONCLUSIONS: Above two treatments could prevent the loss of cancellous bone, reduced the resorption caused by OVX, protected trabecular microarchitecture, and stimulated bone formation significantly. The combined treatment avoided potential mineralization defect caused by F-Ca treatment alone, and two treatments maintained mechanical strength at femoral midshaft.

Animals↗

PubMed1999

[Evaluation of the risk of vertebral fracture predictable with quantitative tibial ultrasound velocity test in postmenopausal women].

OBJECTIVE: To investigate predicting value of increased risk of vertebral fracture associated with reduction of tibial ultrasound velocity (SOS) test in postmenopausal women. METHODS: 193 menopausal women aged(54.4 +/- 7.3) years were included in our study. Post menopausal period of these subjects were (16.0 +/- 7.8) years. These participants received tibial ultrasound speed (SOS) test, DEXA for lumbar 2-4, femoral neck wards triangle and trochant, as well as SPA for 1/3 and 1/10 of distal forearm. Vertebral fracture was determined by radiograph of lateral lumbar and thoracic spine. RESULTS: 54 subjects were found at least one vertebral deformation, and no vertebral deformation was found in other 139 subjects. Tibial SOS was significantly lower in subjects with than without vertebral fracture [(3,651.9 +/- 188.3) vs (3,731.3 +/- 140.8), P < 0.01], The similar results were also found in BMD. The analysis of logistic regression showed: odds ratio (OR) of SOS to vertebral fracture was 1.86(P < 0.01) when 1 standard deviation of SOS changed. It was lower than OR of BMD by DEXA(2.25-3.28, all P < 0.001), and similar with OR of BMD by SPA (1.50-1.96). CONCLUSIONS: Low SOS was associated with presence of vertebral fracture in postmenopausal women. SOS could predict the risk of vertebral fracture, 86% of the risk of vertebral fracture increased when 1 standard deviation of SOS reduced.

Aged↗

PubMed1999

[Tissue specificity and expression of a human sperm protein's gene BSD-2.4].

OBJECTIVE: To investigate the tissue specificity and expression in spermatogenic stage of BSD-2.4 cDNA which might be related with fertility and its sequence was received by GenBank. METHODS: Dot blot, Northern blot, and in situ hybridization were used. RESULTS: Northern blot analysis of sixteen human tissues showed that BSD-2.4 cDNA had one transcript only with testis. BSD-2.4 mRNA was detected in germ cells of human testis. CONCLUSIONS: BSD-2.4 is a testis-specific protein. The cDNA was expressed throughout the stages of the spermatogenic cycle.

Animals↗

PubMed1999

[Studies on the antitumour effect of Alocasia macrorrhiza].

Models of transplanted tumour in mice and human cancer enograft in nude mice were used to evaluate the antitumour effect of water extract of Alocasia macrorrhiza. Results showed that the inhibitory rate against S180 in mice was 29.38%, and the inhibitory rate against transplantable humman gastroadenitis in nude mice was 51.72%. No antitumour effect was shown against ECA in mice.

Adenocarcinoma↗

PubMed1999

[Relationship between HBV DNA serum level and acute exacerbation of the disease in chronic hepatitis B patients].

OBJECTIVE: In this study, we evaluated the relationship between HBV DNA serum level and acute hepatic exacerbation of the disease in chronic hepatitis B patients. METHODS: A series of serum samples from 14 patients of acute exacerbation of chronic hepatitis B were analyzed for alteratieus in serum HBV DNA and alanine transaminase (ALT) level before, during, and after episode of an acute exacerbation. The serum HBV DNA concentrations were tested by the quantitative polymerase chain reaction (PCR) using the AmpliSensor assay. RESULTS: 1. Serum HBV DNA average level in 11 patients significantly increased from 7.148 +/- 2.008(logarithm) at 2-8 weeks before maximum injury of liver to 8.416 +/- 2.160 (logarithm), the time that ALT reached its peak, and then, following the declining of ALT level, decreased to 6.093 +/- 1.428 (logarithm). In 9 of 11 cases, the HBV DNA peak value occurred before the ALT peak level or at the same time; 2. Two patients who experienced several episodes of acute exacerbation showed that the appearance of acute hepatic injury and the relatively normal liver function occurred alternatively. Whereas, one patient with liver cirrhosis showed persistence of high level viremia in three episodes of acute exacerbation in one year. CONCLUSION: 1. This investigation revealed a clear correlation between increasing level of serum HBV DNA and acute exacerbation of patients with chronic hepatitis B. The findings suggest that host's immune response which causes acute exacerbation of liver injury in patients with chronic hepatitis B is triggered by the change of viremia and HBV replication; 2. Patients with severe chronic active hepatitis and persistent hepatitis B virus replication are at very high risk of rapid progression to cirrhosis.

Adult↗

PubMed1998

Non-additive interaction between nicotinic cholinergic and P2X purine receptors in guinea-pig enteric neurons in culture.

1. Acetylcholine (ACh)-activated currents and their interaction with ATP-activated currents were studied in primary cultures of myenteric neurons from guinea-pig small intestine using patch clamp techniques. Peak currents caused by co-application of ACh (1 mM) and ATP (300 microM) were 78 +/- 2 % of the sum of currents activated by each agonist alone (P < 0.05, n = 29). Reversal potentials measured during co-application of ACh and ATP did not differ from those measured during application of ACh or ATP alone. Addition of BAPTA (10 mM) to the pipette solution or replacement of extracellular Ca2+ with Na+ did not prevent occlusion. 2. Responses caused by co-application of 5-HT (300 microM), acting at 5-HT3 receptors, and ACh (3 mM) or ATP (1 mM) were additive (94 +/- 3 or 96 +/- 4 %, respectively, of the sum of currents activated by 5-HT and ACh or ATP alone; P > 0.05). Currents caused by GABA (1 mM), acting at GABAA receptors, and ACh (3 mM) or ATP (1 mM) were also additive (105 +/- 4 or 100 +/- 3 %, respectively, of the sum of currents activated by GABA and ACh or GABA and ATP applied separately; P > 0. 05). 3. Single channel currents caused by ACh and ATP in the same outside-out patches were less than additive (85 +/- 10 % of the predicted sum, P < 0.05). 4. P2X receptors and nicotinic cholinergic receptors (nAChRs) are linked in a mutually inhibitory manner in guinea-pig myenteric neurons. The functional interaction does not involve ligand binding sites, Ca2+-dependent mechanisms, a change in the driving force for Na+ or cytoplasmic signalling mechanisms.

Acetylcholine↗

PubMed1998

Inherited duplication Xq27-qter at Xp22.3 in severely affected males: molecular cytogenetic evaluation and clinical description in three unrelated families.

We describe the clinical phenotype in four males from three families with duplication (X)(qter-->q27::p22.3-->qter). This is an unusual duplication of the distal long arm segment, Xq27-qter, onto the distal short arm of the X chromosome at Xp22.3, as shown by fluorescent in situ hybridization analysis with multiple X-specific probes. The patients are young male offspring of three unrelated, phenotypically normal carrier women. The affected males have similar clinical manifestations including severe growth retardation and developmental delay, severe axial hypotonia, and minor anomalies. Such clinical similarity in three unrelated families demonstrates that this chromosome abnormality results in a new and distinct clinical phenotype. Replication studies, performed on two of the mothers, provided evidence that inactivation of the abnormal X chromosome permitted the structural abnormality to persist in these families for a generation or more in females without phenotypic expression.

Adult↗

PubMed1998

Spatial changes in the transmembrane potential during extracellular electric stimulation.

The purpose of this study was to determine the spatial changes in the transmembrane potential caused by extracellular electric field stimulation. The transmembrane potential was recorded in 10 guinea pig papillary muscles in a tissue bath using a double-barrel microelectrode. After 20 S1 stimuli, a 10-ms square wave S2 shock field with a 30-ms S1-S2 coupling interval was given via patch shock electrodes 1 cm on either side of the tissue during the action potential plateau. Two shock strengths (2.1+/-0.2 and 6.5+/-0.6 V/cm) were tested with both shock polarities. The recording site was moved across the tissue along fibers with either 200 micrometer (macroscopic group [n=5], 12 consecutive recording sites over a 2. 2-mm tissue length in each muscle) or 20 micrometer (microscopic group [n=5], 21 consecutive recording sites over a 0.4-mm tissue length in each muscle) between adjacent recording sites. In the macroscopic group, the portion of the tissue toward the anode was hyperpolarized, whereas the portion toward the cathode was depolarized, with 1 zero-potential crossing from hyperpolarization to depolarization present near the center of the tissue. In the microscopic group, only 1 zero-potential crossing was observed in the center region of the tissue, whereas, away from the center, only hyperpolarization was observed toward the anode and depolarization toward the cathode. Although these results are consistent with predictions from field stimulation of continuous representations of myocardial structure, ie, the bidomain and cable equation models, they are not consistent with the prediction of depolarization-hyperpolarization oscillation from representations based on cellular-level resistive discontinuities associated with gap junctions, ie, the sawtooth model.

Animals↗

PubMed1998

Role of EP2 receptors and cAMP in prostaglandin E2 regulated expression of type I collagen alpha1, lysyl oxidase, and cyclooxygenase-1 genes in human embryo lung fibroblasts.

In a recent communication, we demonstrated that prostaglandin E2 (PGE2) lowers basal while it ablates interleukin-1beta((IL-1beta) and transforming growth factor-beta (TGFbeta) upregulated lysyl oxidase (LO) mRNA levels. Correspondingly, PGE2 increases cyclooxygenase-1 (COX1) mRNA in diploid, human embryo lung fibroblasts (IMR90) [Roy et al., 19961. We now report that these actions by PGE2 are routed through cAMP via the PGE2, EP2 receptor. Among the PGE2 receptor types, the IMR90 predominantly express the EP2 mRNA. These cells also express EP3 and EP4 mRNA at comparatively low levels. Northern blot analyses show that 11-deoxy PGE1, an EP2/EP4 agonist, emulates the action of PGE2. In a similar manner to PGE2, 11-deoxy PGE1 decreases basal and TGF-beta induced type I collagen alpha1 (COL) mRNA, basal and IL-1beta induced LO mRNA while it increases COX1 mRNA. Sulprostone, an EP3/EP1 agonist, has no effect on the expression of these three genes. Forskolin, an adenylate cyclase activator, acts in a very similar manner to PGE2 or 11-deoxy PGE1. It suppresses both basal and TGF-beta induced COL mRNA levels. Both PGE2 and 11-deoxy PGE1 increase cAMP to a level comparable with forskolin. The role of the EP2 receptor in controlling collagen production is further underscored in the immortalized Rat-1 fibroblasts, derived from Fischer rat embryos, which do not express detectable EP2 mRNA. In these cells, PGE2 has little effect on COL mRNA level, whereas forskolin increases it. Furthermore, forskolin increases cAMP level in Rat-1 cells, whereas PGE2 does not. Overall, these results illustrate that much of the PGE2 action on the expression of COL, LO, and COX1 genes is mediated through the EP2 receptor and a subsequent increase in intracellular cAMP.

Alprostadil↗

PubMed1998

Phenotype and genotype of advanced premalignant head and neck lesions after chemopreventive therapy.

BACKGROUND: The goal of chemoprevention is to reduce the risk of cancer development by reversing or blocking the tumorigenic process through the use of pharmacologic or natural agents. To determine the potential role of genetic alterations in assessing cancer risk and in evaluating the efficacy of chemopreventive agents, we studied 22 patients with advanced premalignant lesions of the head and neck who were part of a prospective cancer prevention trial that is investigating a regimen of 13-cis-retinoic acid, interferon alfa, and alpha-tocopherol administered for 12 months or until disease progression. METHODS: We used polymerase chain reaction analysis of microsatellite DNA sequences in cells from precancerous lesions to determine the frequencies of genetic alterations--namely, loss of heterozygosity (LOH) and microsatellite instability--at chromosomal loci that are commonly deleted in head and neck cancer. RESULTS: Prior to treatment, 17 (81%) of 21, eight (44%) of 18, and eight (42%) of 19 patients who were informative (i.e., heterozygous) at chromosomes 9p21, 3p14, and 17p13, respectively, exhibited LOH in at least one of their lesion biopsy specimens. Among nine patients who exhibited LOH at chromosome 9p21 in pretreatment biopsy specimens and who had completed at least 5 months of therapy, the genetic loss persisted in eight--including three of the four patients who exhibited complete histologic responses (i.e., no evidence of dysplasia in their biopsy specimens). IMPLICATION: Our data suggest that clinical and histologic assessments of the response to chemopreventive agents may be insufficient to determine their efficacy and that critical genetic alterations could be used as independent biomarkers to augment the ability to evaluate the efficacy of such agents.

Antineoplastic Agents↗

PubMed1998

Estrogen receptor does not directly regulate the murine Muc-1 promoter.

Muc-1 is a heavily O-glycosylated, type 1 membrane glycoprotein present on the surface of polarized secretory uterine epithelial cells. Previous studies have shown that treatment of ovariectomized mice with 17-beta-estradiol (E2) strongly induces Muc-1 mRNA expression in an estrogen receptor (ER)-mediated fashion in the uterus. In this study, the 5.4 kb Muc-1 gene promoter has been isolated from a mouse genomic library and the proximal 1.85 kb region has been sequenced. Sequence analysis revealed the presence of one potential full estrogen response element (ERE) (GCTCGCGGTGACC) located at -748 to -735 bp in the Muc-1 promoter and several potential ERE half sites. Electrophoretic mobility shift assays (EMSA) showed that neither ERalpha nor ERbeta bind efficiently to this sequence. Transient cotransfection assays using constructs containing various deletion mutations of the 5' Muc-1 flanking sequences showed that E2 had no direct stimulation on promoter-driven reporter in NMuMG cells or primary mouse uterine epithelial cells, but did stimulate a consensus ERE CAT-reporter gene activity. In addition, E2-treatment of Weg-ER cells, a mouse uterine epithelial cell line stably expressing human ERalpha, did not restore endogenous Muc-1 expression or activate Muc-1 promoter-driven CAT activity. These results indicate that regions of the Muc-1 gene promoter within -1838 to +43 bp do not respond to E2 and ER stimulation and that ER alone is not sufficient to restore Muc1 gene expression. Deletion analyses also revealed that the sequence between -73 and +43 bp of the Muc-1 promoter is the minimal promoter region required for maximal Muc-1 promoter activity. Collectively, these results demonstrate that ER does not directly regulate the 1.85 kb murine Muc-1 gene promoter. Therefore, E2 control of uterine Muc-1 gene expression is likely to be indirect, i.e. mediated by stromal cell-derived factors.

Animals↗

PubMed1998

Gelatinase B-deficient mice are resistant to experimental bullous pemphigoid.

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease characterized by deposition of autoantibodies at the basement membrane zone. In an experimental BP model in mice, the subepidermal blistering is mediated by antibodies directed against the hemidesmosomal protein BP180 (collagen XVII, BPAG2), and depends on complement activation and neutrophil infiltration. Gelatinase B is present in BP blister fluid and can cleave BP180. In this study we investigated the role of gelatinase B in the immunopathogenesis of experimental BP using mice containing targeted disruption of the gelatinase B (MMP-9, 92 kD gelatinase) gene. Gelatinase B-deficient mice were resistant to the blistering effect of intracutaneous anti-mBP180 antibodies, although these mice showed deposition of autoantibodies at the basement membrane zone and neutrophil recruitment to the skin comparable to that observed in the control mice. Interleukin 8 given intradermally concomitantly with pathogenic anti-mBP180 elicited a significant neutrophil recruitment into the skin in gelatinase B-deficient mice, but blistering did not occur. However, gelatinase B-deficient mice reconstituted with neutrophils from normal mice developed blistering in response to anti-mBP180 antibodies. These results implicate neutrophil-derived gelatinase B in the pathogenesis of experimental BP and might lead to novel therapeutic strategies for BP.

Animals↗