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Biomedical subjects

J Tang

Publications and source records attributed to J Tang.

At least 109 records · Page 6Linked to original sources
PubMed2001

The role of hypertension-related gene in aortic vascular smooth muscle cells from mice and rats.

OBJECTIVE: To study the role of hypertension-related gene (HRG-1) in cardiovascular disease. METHODS: The expression of HRG-1 was analyzed with RT-PCR and Northern blotting. Vascular smooth muscle cell (VSMC) proliferation was measured with 3H-TdR incorporation and was confirmed with histological analysis. RESULTS: Northern blot analysis showed that HRG-1 mRNA was expressed not only in VSMC, but also in various rat tissues (heart, brain, lung, kidney, and liver). In addition, the expression of HRG-1 mRNA in heart, brain, kidney and liver of spontaneously hypertensive rat (SHR) was lower than that in the same tissues of Wistar-Kyotorat (WKY). Semi-quantitative RT-PCR and histological analysis showed that the expression of HRG-1 mRNA in ApoE-knockout mice and in animal models of restenosis was decreased and neointimal formation was observed in both models. ET, AII, and IL-1 stimulating VSMC proliferation reduced the expression of HRG-1 mRNA of VSMC. Atrial natriuretic factor (ANF), calcitonin gene-related peptide and adrenomedullin, inhibited VSMC proliferation and elevated the expression of HRG-1 mRNA. These effects could be blocked or attenuated by their corresponding antagonists or antibodies. CONCLUSION: HRG-1 is a gene related to VSMC proliferation. It may play an important role in several occlusive cardiovascular diseases including atherosclerosis, restenosis and hypertension.

Animals↗
PubMed2001

[Transrectal ultrasound examination of the prostate in 100 cases of prostate cancer].

OBJECTIVE: To evaluate the clinical value of transrectal ultrasound (TRUS) examination of the prostate in the diagnosis of prostate cancer (PCA). METHODS: The sonographic and clinical data of 100 patients with PCA were analyzed retrospectively. RESULTS: There was single lesion in 59 patients, diffuse lesion in 17 patients. The size of tumor in 35 patients was < or = 1.5 cm. TRUS in the diagnosis of PCA had an accuracy of 76.0%, specificity of 89.4%, false positive rate of 10.6% and negative predictive value of 88.9%. The level of prostate specific antigen (PSA) increased with the increase in the size of the tumor (P < 0.05). The PSA level of patients with poorly differentiated PCA was significantly higher than that in patients with well differentiated PCA. CONCLUSION: TRUS examination is a convenient procedure for the diagnosis of PCA in its early stage.

Aged↗
PubMed2001

[Physiological indices for evaluating iron-toxicity tolerance of rice (Oryza sativa L.)].

This paper studied the content malodialdehyde (MDA) and the leakage rate of electrolyte in leaves of various rice varieties with different iron-toxicity tolerance and of Echinochloa crusgalli under excessive Fe2+ (160 mg.L-1) stress. The results showed that both the MDA content and the leakage rate of electrolyte in leaves of plants were significantly and negatively correlated with the tolerance of test plants to iron toxicity. It was suggested that both MDA content and leakage rate of electrolyte could be used as the index for evaluating the tolerance to iron toxicity.

Biomass↗
PubMed2001

[The predomination of rotavirus G3 serotype among children with diarrhea in Lulong County in 1998].

OBJECTIVE: To investigate the epidemiology of rotavirus diarrhea among children in rural population. METHODS: 120 stool specimens collected from children with diarrhea during the winter of 1998 in Lulong County, Hebei Province were examined for rotavirus by PAGE and ELISA and for serotype by ELISA and PCR. RESULTS: Rotavirus was detected in children aged between 2-24 months. The positive rate of rotavirus was 39.2% and the ratio of male to female was 1-1.47. All rotavirus RNA profiles were long pattern. The distribution of rotavirus serotypes was type 3(61.7%), followed by type 1(36.2%), and type 4(6.4%). CONCLUSIONS: The epidemiology of rotavirus diarrhea during 1998 rotavirus season in Lulong County was similar to that of other regions in China, but rotavirus serotype G3 was a prevalent strain in Lulong County, which was uncommon and different from the predominant G1 in other places throughout China.

Child, Preschool↗
PubMed2001

[Detection of TT virus DNA and sequence analysis of TTV gene in sera from young children in Nanjing].

OBJECTIVE: To investigate the prevalence of TTV genomes in young children from Nanjing and establish the PCR method for detecting TTV DNA. METHODS: A hemi-nested polymerase chain reaction (PCR) assay was established to detect TTV DNA in 110 young children and two PCR-amplified products were sequenced and the data were analyzed with the computer programs. RESULTS: TTV DNA was detected in 14 out of 110 children, and 222 bp sequences of 2 isolates from the children were analyzed. Compared with representative of published isolates, they have the nucleotide identity of 93.7%-98.6% with TX011. CONCLUSIONS: The infection rate of TTV in children is 12.73%, and 2 isolates from children belong to subgroup G1b. Our results indicates that TTV could be transmitted via other pathway besides hematogenous one, and TTV could be carried by healthy population.

Base Sequence↗
PubMed2001

[Studies on insulin-like growth factor I receptor in fetal rats with intrauterine growth retardation].

OBJECTIVE: This study was conducted to detect the localization of the insulin-like growth factor I receptor (IGF-I R) in the cells and tissues in the rats with intrauterine growth retardation (IUGR) and normal growth rats. METHODS: 21 pregnant rats were randomly divided into the experimental group (IUGR) (n = 12) and the control group (n = 9). Animal models for IUGR were established by clamping the uterine vasculature of pregnant rats for 20 minutes on day 14 of gestation. The control group rats were subjected to Sham-operation. On day 22 of gestation, fetal rats were delivered by cesarean section. Immunohistochemical assay was performed to detect the IGF-I R expression on liver and lung using specific polyclonal antibodies to rat IGF-I R. RESULTS: In the experimental group, the IUGR rats' body weight, height, and the weight of their liver, lung and the placenta were significantly lower than those in the control group. In the IUGR rats' liver, the area ratio of IGF-I R was increased and the average gray level was decreased, compared with those in the control group. In the IUGR rats' lung, the area ratio of IGF-I R was increased, compared with that in the control group, but no difference of average gray level was observed between the two groups. CONCLUSION: The increased expression of IGF-I R in rats with IUGR, may be due to the decrease of IGF-I and the compensative mechanism of the body.

Animals↗
PubMed2001

[Diagnostic significance of audiological and vestibular function examination in the pontocerebellar angle tumor].

OBJECTIVE: To study the diagnostic value of audiological and vestibular function examination in the pontocerebellar angle tumor. METHOD: The data of audiological and vestibular function test were analized retrospectively in 20 subjects with tumors of the pontocerebellar angle. RESULT: Pure tone and ABR waveforms were abnormal in 20 subjects (21 ears), moreover acoustic stapedius reflex and the vestibular function were abnormal in 19 subjects. CONCLUSION: It's valuable that audiological and vestibular function examinations are able to diagnosis the pontocerebellar angle tumor.

Adult↗
PubMed2001

[Plasma cell granuloma of maxillary sinuses].

OBJECTIVE: To study the clinical features and treatment of plasma cell granuloma in maxillary sinuses. METHOD: The clinical information of 3 cases was reported and the literatures were also reviewed. RESULT: All of the 3 cases were cured after Caldwell-Luc operation combined with oral corticosteroids and antiallergic agent. Recurrence hasn't been found in half to 2 years follow-up period. CONCLUSION: Plasma cell granuloma of maxillary sinus is a chronic inflammatory lesion with unknown origin. In almost all of the cases, CT images showed some degree of involvement of the bony wall of the maxillary sinuses. The imaging findings mimicker malignant tumors. But the prognosis were quite well in most of the patients.

Combined Modality Therapy↗
PubMed2001

[Study on the analytical methods of catechins in tea and green tea polyphenol samples by high performance liquid chromatography].

Hypersil BDS C18 and Zorbax SB C18, suitable to separate simultaneously seven kinds of catechins and caffeine, were screened out from seven brands of reversed-phase columns. Mobile phase was a solution of methanol-water-acetic acid (or trifluoro acetic acid). Seven kinds of catechins in tea samples from six places in China and three green tea polyphenol(GTP) samples from different producers were separated and determined in 30 min by isocratic and gradient elutions. The effects of mobile phase components and temperature of column on retention parameters of catechins and caffeine are reviewed. Chromatographic conditions and pretreatment methods of samples were optimized. Gallocatechin gallate(GCG) and (-)-catechin gallate(CG) were identified by electrospray ionization mass spectrometry(ESI-MS) and prepared by high performance liquid chromatography for quantitative analysis. The other catechins, (-)-epigallocatechin (EGC), (+)-catechin (D-C), (-)-epicatechin(EC), (-)-epigallocatechin gallate(EGCG), (-)-epicatechin gallate(ECG) were identified with standards.

Caffeine↗
PubMed2001

[Local recurrence of nasopharyngeal carcinoma with normal mucous membrane after radiation therapy: MR imaging findings].

OBJECTIVE: The purpose of this work was to investigate and analyze the MR imaging features of postradiation local recurrence of nasopharyngeal carcinoma (NPC) with normal mucous membrane. METHODS: 24 such cases were studied. The diagnosis of NPC recurrence was pathologically confirmed in 15 patients, and was corroborated by repeated radiation therapy and serial follow-ups in 9 patients. MR imaging routine procedures and Gd-DTPA enhancement were performed for all patients. RESULTS: The MR imaging findings were as follows: 1. The recurrent tumor mass was located in the prestyloid space in 8 patients, with skull base erosion and intracranial infiltration in 7 patients; 2. Retrostyloid space recurrence in 2 patients; 3. Direct bony erosion of the skull base in 7 patients; 4. Recurrence in nasal cavity and ethmoid sinuses in 3 patients; 5. Submucous cystic recurrence in 2 patients; 6. Mixed patterns of recurrence in 2 patients. Except 2 cases of cystic tumor recurrence, all cases exhibited slight hypo- or iso-intensity on T1-weighted images, slight hyper-intensity on T2-weighted images, and moderate to marked enhancement after Gd-DTPA administration. CONCLUSION: There are several special patterns of local NPC tumor recurrence after radiation therapy in the presence of normal nasopharyngeal mucosa. MR imaging is the method of choice to depict the location and extent of NPC tumor recurrence.

Adult↗
PubMed2001

[The intraoperative application of neural response telemetry with the nucleus CI24M cochlear implant].

OBJECTIVE: To test device integrity and objective auditory reaction for cochlear implant patients intraoperatively. METHODS: Our protocol for intraoperative testing of the implant device includes device electrode impedance test and neural response telemetry (NRT), which measures the electrically evoked auditory nerve compound action potentials (ECAP). RESULTS: We completed electrode integrity tests and NRT intraoperatively on 40 patients with the Nucleus CI24M cochlear implant. We have measured normal implant function on all 40 patients and obtained ECAP results from 39 patients. Out of 33 patients with normal inner ear, typical ECAPs were recorded in 195 electrodes in all 198 testing electrodes(98.5%). In 7 patients with inner ear Mondini dysphasia, affirmative ECAP waveforms were recorded in 26 electrodes in all 42 testing electrodes. The basal electrode ECAP threshold was higher than that of the epical one. CONCLUSIONS: The intraoperative measurements of device function and NRT are quite simple, quick and with high accuracy. Inner ear malformation is an important factor that may affect NRT results.

Action Potentials↗
PubMed2001

[An IR study of ion solvation and association of lithium perchlorate in some organic solvents].

The infrared (IR) spectra of propylene carbonate (PC), gamma-butyrolactone (BL) and diethyl carbonate (DEC) in the presence of LiClO4 have been investigated. It is shown that the interactions between Li+ and these solvents occur on the oxygen atoms of the carbonyl of solvent molecules. On the other hand, spectral curve fitting for band shape of perchlorate anion shows the presence of ion association in these solutions.

4-Butyrolactone↗
PubMed2001

[Transmission properties of Faraday anomalous dispersion optical filter at 532 nm].

In this paper the properties of an excited-state potassium Faraday anomalous dispersion optical filter in potassium vapor with a pump wavelength of 769.90 nm (i.e. 4S1/2-->4P1/2 transition) and a signal wavelength of 532 nm (i.e. 4P1/2-->8S1/2 transition) are calculated and discussed. The filter's transmissions versus the laser pump power and the external magnetic-field are obtained. The theoretical results show the transmission characteristics of the filter are relatively insensitive to the laser pump power and magnetic strength. The laser pump powers require range from 0.8 to 6 mW.cm-2. Our model predicts a peak transmission of 50% and an equivalent band-width of 4 GHz for the filter operating on the 4P1/2<--8S1/2 transition in potassium. The optical filter at 532 nm presented in this paper may be used to detect the practical and important frequency-doubled Nd:YAG laser.

English Abstract↗
PubMed2000

Mechanisms of [Ca2+]i elevation by H2O2 in islets of rats.

Activity of reactive oxygen species is elevated in diabetes mellitus and has been implicated in the destruction of cellular components. The toxic effect of reactive oxygen species was investigated by testing the effect of H2O2 on [Ca2+]i in isolated islets of Langehans. H2O2 increased [Ca2+]i in a dose-dependent manner, which was irreversible at high concentrations. The maximum effect of H2O2 on [Ca2+]i was larger than those of KCl, glucose, ATP, carbachol and endothelin-1. The effect of H2O2 was only partially attenuated by removal of external Ca2+ and by the in-organic Ca2+ channel blocker nickel, but was not blocked by voltage-dependent or -independent Ca2+ channel blockers nimodipine, nicardipine, SK&F 96365, econazole and lanthanum. H2O2, disrupted [Ca2+]i homeostasis in islets by affecting both release and influx of Ca2+ and causing dysfunction of Ca2+ clearance systems and may contribute to the pathological process of diabetes.

Animals↗
PubMed2000

Ion channel behavior of supported bilayer lipid membranes on a glassy carbon electrode.

A new kind of solid substrate, a glassy carbon (GC) electrode, was selected to support lipid layer membranes. On the surface of the GC electrode, we made layers of didodecyldimethylammonium bromide (a synthetic lipid). From electrochemical impedance experiments, we demonstrated that the lipid layers on the GC electrode were bilayer lipid membranes. We studied the ion channel behavior of the supported bilayer lipid membrane. In the presence of perchlorate anions as the stimulus and ruthenium(II) complex cations as the marker ions, the lipid membrane channel was open and exhibited distinct channel current. The channel was in a closed state in the absence of perchlorate anions.

Carbon↗
PubMed2000

Association of mammalian trp4 and phospholipase C isozymes with a PDZ domain-containing protein, NHERF.

Mammalian homologues of Drosophila Trp have been implicated to form channels that are activated following the depletion of Ca(2+) from internal stores. Recent studies indicate that actin redistribution is required for the activation of these channels. Here we show that murine Trp4 and Trp5, as well as phospholipase C beta1 and beta2 interact with the first PDZ domain of NHERF, regulatory factor of the Na(+)/H(+) exchanger. We demonstrated the association of Trp4 and phospholipase C-beta1 with NHERF in vivo in an HEK293 cell line expressing Trp4 and in adult mouse brain by immuno-coprecipitation. NHERF is a two PDZ domain-containing protein that associates with the actin cytoskeleton via interactions with members of ezrin/radixin/moesin family. Thus, store-operated channels involving Trp4 and Trp5 can form signaling complexes with phospholipase C isozymes via interactions with NHERF and thereby linking the lipase and the channels to the actin cytoskeleton. The interaction with the PDZ protein may constitute an important mechanism for distribution and regulation of store-operated channels.

Amino Acid Sequence↗
PubMed2000

Dynamics and folding of single two-stranded coiled-coil peptides studied by fluorescent energy transfer confocal microscopy.

We report single-molecule measurements on the folding and unfolding conformational equilibrium distributions and dynamics of a disulfide crosslinked version of the two-stranded coiled coil from GCN4. The peptide has a fluorescent donor and acceptor at the N termini of its two chains and a Cys disulfide near its C terminus. Thus, folding brings the two N termini of the two chains close together, resulting in an enhancement of fluorescent resonant energy transfer. End-to-end distance distributions have thus been characterized under conditions where the peptide is nearly fully folded (0 M urea), unfolded (7.4 M urea), and in dynamic exchange between folded and unfolded states (3.0 M urea). The distributions have been compared for the peptide freely diffusing in solution and deposited onto aminopropyl silanized glass. As the urea concentration is increased, the mean end-to-end distance shifts to longer distances both in free solution and on the modified surface. The widths of these distributions indicate that the molecules are undergoing millisecond conformational fluctuations. Under all three conditions, these fluctuations gave nonexponential correlations on 1- to 100-ms time scale. A component of the correlation decay that was sensitive to the concentration of urea corresponded to that measured by bulk relaxation kinetics. The trajectories provided effective intramolecular diffusion coefficients as a function of the end-to-end distances for the folded and unfolded states. Single-molecule folding studies provide information concerning the distributions of conformational states in the folded, unfolded, and dynamically interconverting states.

Amino Acid Sequence↗