Biomedical subjects

Ming Tang

Publications and source records attributed to Ming Tang.

51 records · Page 3Linked to original sources

PubMed2004

[Isolation of partial outer supporting cells from guinea pig cochlea].

OBJECTIVE: To investigate the method of isolating partial outer supporting cells (Deiters' cells, Hensen cells and Outer pillar cells) from guinea-pig cochlea and to try to establish the morphological criteria for these outer supporting cells viability. METHOD: The basal membrane was dissected from the pigmental guinea pig cochlea, and th incubated with enzyme (0.5 mg/ml), then mechanically trituated by micropipetee. RESULT: A large number of living Deiters' cells and Hensen cells could be obtained from the guinea pig cochlear which kept a good condition in the next eight hours. However, the isolated outer pillar cells, with a more vulnerable viability, had a low yield and degenerated in the followed five hours. CONCLUSION: The key to success in isolating outer supporting cells, mainly Deiters' cells and Hensen's cells, from the guinea pig cochlea is to familiarize with the anatomical characteristics of the cochlea and to get the intact organ of Corti, as well as to increase the concentration of enzyme. Moreever, the later four criteria for outer hair cells viability are also fit well for these isolated Deiters' cells, Hensen's cells and Outer pillar cells.

Animals↗

PubMed2004

[Quantitative study of diffusion weighted imaging on magnetic resonance imaging in focal hepatic lesions less than 3 cm].

OBJECTIVE: To evaluate the characteristics of MR imaging of hepatic lesions using measurement of apparent diffusion coefficient (ADC) value of hepatic lesions on diffusion weighted imaging. METHODS: MR diffusion weighted images were obtained in patients with 97 hepatic lesions (22 hepatocellular carcinomas, 21 metastatic tumors, 28 hemangiomas, 26 cysts). ADC values were evaluated with different sequences. The ADC ratio of lesion/liver was estimated. RESULTS: Average ADC values of hepatic lesions were as follows: carcinomas (0.91 +/- 0.07) x 10(-3) mm(2)/s, metastatic tumors (1.13 +/- 0.27) x 10(-3) mm(2)/s, cavernous hemangiomas (1.94 +/- 0.37) x 10(-3) mm(2)/s, cysts (3.26 +/- 0.30) x 10(-3) mm(2)/s. The ADC ratio of lesion/liver was significantly different between primary carcinomas and metastatic tumors (P < 0.05). CONCLUSION: Quantitative study in hepatic lesions using ADC values and the ADC ratio of lesion/liver, would improve the accuracy in diagnosing hepatic lesions.

Cysts↗

PubMed2004

Muscarinic cholinergic regulation of L-type calcium channel in heart of embryonic mice at different developmental stages.

AIM: To investigate the muscarinic regulation of L-type calcium current (I(Ca-L)) during development. METHODS: The whole cell patch-clamp technique was used to record II(Ca-L) in mice embryonic cardiomyocytes at different stages (the early developmental stage, EDS; the intermediate developmental stage, IDS; and the late developmental stage, LDS). Carbachol (CCh) was used to stimulate M-receptor in the embryonic cardiomyocytes of mice. RESULTS: The expression of I(Ca-L) density did not change in different developmental stages (P>0.05). There was no difference in the sensitivity of I(Ca-L) to CCh during development (P>0.05). This inhibitory action of CCh was mediated by inhibition of cyclic AMP since 8-bromo-cAMP completely reversed the muscarinic inhibitory action. IBMX, a non-selective inhibitor of phosphodiesterase (PDE), reversed the inhibitory action of M-receptor on I(Ca-L) current by 71.2 %+/-9.2 % (n=8) and 11.3 %+/-2.5 % (n=9) in EDS and LDS respectively. However forskolin, an agonist of adenylyl cyclase (AC), reversed the action of CCh by 14.5 %+/-3.5 % (n=5) and 82.7 %+/-10.4 % (n=7) in EDS and LDS respectively. CONCLUSION: The inhibitory action of CCh on I(Ca-L) current was mediated in different pathways: in EDS, the inhibitory action of M-receptor on I(Ca-L) channel mainly depended on the stimulation of PDE. However, in LDS, the regulation by M-receptor on I(Ca-L) channel mainly depended on the inactivation of AC.

1-Methyl-3-isobutylxanthine↗

PubMed2004

[Isolation of rice genes down-regulated by brown planthopper infestation by suppression subtractive hybridization].

Suppression subtractive hybridization (SSH) was used to isolate rice genes down-regulated by BPH infestation. The SSH cDNA library constructed with the tester cDNA from rice seedlings, and driver cDNA from rice seedlings fed by BPH consists of 200 clones. Fifty clones were randomly picked and screened by reverse Northern dot blot and Northern blot. As a result, two cDNA fragments have been isolated: one is Lhca, which encodes rice photosystem I antenna protein; the other is a novel rice gene, and designated as BpHd002 (Brown planthopper depressed). The cDNA library for rice seedlings was screened using BpHd002 as probe, and a full-length cDNA (BpHd002A) has been isolated. The cDNA is 1 285 bp in length; the putative open reading frame is 519 bp long, which encodes a protein with two CBS domains, homologous with inosine-5'-monophosphate dehydrogenase.

Amino Acid Sequence↗

PubMed2003

Excitatory effects of motilin in the hippocampus on gastric motility in rats.

Intestinal motilin is known to stimulate gastrointestinal motility. Recently, it was shown that the motilin gene and the motilin receptor are expressed in various regions of the brain. We studied whether motilin can activate pathways in the rat hippocampus to stimulate gastric motility. Gastric motility was monitored in conscious rats, whereas extracellular electrical activity recordings of the hippocampus were performed on anaesthetized rats to measure the influence of microinjection of motilin and CCK-8 into the hippocampus and into the cerebral ventricles. We found that neurons in the CA3 region of the hippocampus are sensitive to gastric distension, and that injection of motilin into the hippocampus increased the amplitude of gastric contractions by 35.3+/-6.8%, while CCK-8 injection inhibited motility by -27.3+/-6.8%. The hippocampal motilin-induced stimulation of gastric motility (30.6+/-5.5%) was completely abolished by subdiaphragmal vagotomy (-2.8+/-4.4%) but unaffected by the intravenously applied receptor blockers atropine, phentolamine and propranolol. In vivo extracellular recordings of gastric distension-responsive CA3 neurons revealed that intracerebroventricular administration of motilin increased firing while CCK-8 inhibited firing. These opposite effects of motilin and CCK-8 fit with the nature of the actions of these gut-brain peptides on gastric motility. Our findings suggest that the stimulation of gastric motility by motilin administered in the hippocampus reflects the existence of a functional interaction between the hippocampus and a vago-vagus reflex running via a noncholinergic and nonadrenergic efferent pathway.

Action Potentials↗

PubMed2003

Sequence, distribution and quantification of the motilin precursor in the cat.

Due to motilin's relation to the migrating motor complex (MMC), the physiology of motilin has been mostly studied in man and dog. The cat does not have an MMC pattern, and little is known about cat motilin. Therefore we identified the cat motilin precursor (GenBank accession no. AF127917) and developed a quantitative polymerase chain reaction (PCR) to explore its distribution in the gastrointestinal tract and in the central nervous system (CNS). The precursor is closely related to the dog precursor and consists of an open reading frame of 348bp encoding the signal peptide (25 amino acids), the motilin sequence (22 amino acids) and the motilin associated peptide (69 amino acids). One amino acid of the signal peptide was subject to gene polymorphism. Quantification of motilin messenger RNA (mRNA) was for the first time achieved. It is most abundant in the gastrointestinal tract, with the highest concentration in the duodenum, the lowest in the colon and is not detectable in the corpus. However an important expression was also observed in several regions of the CNS, except the striatum and cerebral cortex. The highest level was in the hypothalamus (although 23-fold lower than in the duodenum), the lowest level in the pons. Moderate levels were found in the thyroid. These data suggest that the physiological role of motilin may extend beyond its effect on gastrointestinal motility.

Amino Acid Sequence↗

PubMed2003

Dementia in community-dwelling elderly patients: A comparison of survey data, medicare claims, cognitive screening, reported symptoms, and activity limitations.

BACKGROUND AND OBJECTIVE: Population-based estimates of dementia can vary widely depending on the data source and methodology used to assess cognitive impairment. The aim of this study was to assess individual and composite measures of dementia constructed using survey and administratively collected medical data for the purpose of improving insight into inherent and avoidable biases and the interpretation of these measures. METHODS: A national survey of 5089 community-dwelling elderly persons was linked to 5 years of Medicare claims. Kappa coefficients were used to assess dementia agreement between survey, cognitive screen, and claims. Odds ratios (ORs), adjusted for age, gender, and education, were computed to assess the relation of single- and multi-source dementia variables to cognitive symptoms and activity limitations. RESULTS: Dementia prevalence among persons aged 65 and over ranged from 4.5% to 16.8% across sources. Agreement in case identification between data sources was low, ranging from 0.15 to 0.41. Despite low agreement, ORs were consistently increased for limitations in cognitively related activities/symptoms and non-overlapping dementia sources. CONCLUSION: The finding that non-overlapping dementia data sources are associated with significantly increased limitations in cognitive activities suggests that forecasts of national dementia-related resource use based on single-source data could produce serious underestimates of future need.

Activities of Daily Living↗

PubMed2003

[The simultaneous isolation of outer hair cells and Deiters' cells from the cochlea of the guinea pig].

OBJECTIVE: To investigate the simultaneous method of isolating outer hair cells and Deiters' cells from the organ of Corti of the guinea-pig cochlea. METHOD: The organ of Corti was dissected from the pigmental guinea pig cochlea, and then treated with papain. RESULT: A large number of living outer hair cells and Deiters' cells were obtained synchronously from the guinea pig. CONCLUSION: The key to success in isolating outer hair cells and Deiters' cells from the cochlea is to know very well the anatomical characteristics of the cochlea and keep the contact the organ of Corti.

Animals↗

PubMed2003

[Effect of linopirdine on potassium currents in isolated outer hair cells and Deiters' cells of the cochlea from guinea pig].

OBJECTIVE: To study the effect of linopirdine, a selective blocker of KCNQ channel family, on the whole-cell potassium currents in isolated outer hair cells (OHCs) and Deiters' cells of the cochlea from guinea pig and to probe the distribution of KCNQ channel family in OHC and Deiters' cells. METHODS: Using the patch clamp whole-cell recording, IK (tetraethylammonium-sensitive outward potassium currents) and IKa (inward potassium currents activated at negative potential) were measured before and after the administration of linopirdine in OHCs. Simultaneously, IK (the outward rectifier potassium current) was recorded in Deiters' cells. RESULTS: IK was partly reduced after the administration of linopirdine in OHCs, moreover, IKa was totally inhibited. However, IK in Deiter's cells was not decreased. CONCLUSION: KCNQ channel family could only involve in constructing the variant potassium channels in outer hair cells, but not in Deiters' cells.

Animals↗

PubMed2002

Inhibitory effect of adrenomedullin on L-type calcium currents in guinea-pig ventricular myocytes.

The effects of adrenomedullin (ADM) on the L-type calcium currents (I(Ca,L)) and the mechanism of the signal transduction process were studied. Enzymatically isolated guinea-pig ventricular myocytes were used to measure ICa,L with whole-cell patch-clamp techniques. ADM at the concentrations of 1-100 nmol/L decreased ICa,L in a dose-dependent manner (P<0.05). ADM22-52) (100 nmol/L), a specific ADM-receptor antagonist, completely abolished the ADM-induced inhibition of ICa,L. Pretreatment of the cells with H-89 (10 micromol/L), a specific PKA inhibitor, did not attenuate the effects of ADM. Intracellular application of 10 micromol/L PKC19-36), a specific PKC inhibitor, prevented the ADM-induced inhibition of the ICa,L, while the specific PKC activator PMA could mimic the effects of ADM on the ICa,L. PMA (1 micromol/L) decreased the ICa,L by 32.26+/-4.20%(P<0.05). These findings indicate that ADM can inhibit the ICa,L in guinea-pig ventricular myocytes, and the inhibition is mediated by the specific ADM-receptor and an activation of protein kinase C.

Adrenomedullin↗

PubMed2002

[Administration of motilin into the lateral hypothalamus increases gastric antrum motility and activates the dorsal vagal complex in rats].

The effects of administration of motilin into the lateral hypothalamic area (LHA) on gastric antrum motility in conscious rats and on gastric distention (GD) sensitive neurons in dorsal vagal complex (DVC) in anesthetized rats were studied. Microinjection of motilin (0.37 nmol/0.5 microl) into the LHA increased the gastric antrum motility index by 76.29 +/- 4.09% (P<0.01). In 60 GD sensitive neurons, firing rate increased in 39 neurons (65%) and decreased in 21 neurons (35%), which were classified as GD-excitatory and GD-inhibitory neurons, respectively. Firing rate by 7.17 +/- 7.89% within 1.5 min in 15 of 24 GD-excitatory neurons, and firing rate increased by 44.35 +/- 7.89% in 12 of 14 GD-inhibitory neurons after motilin microinjection into the LHA. The results suggest that exogenous motilin in LHA plays a role in the regulation of gastric antrum motility possibly via the vagal pathway from LHA-DVC to the stomach.

Animals↗

PubMed2002

Developmental changes in functional expression and beta-adrenergic regulation of I(f) in the heart of mouse embryo.

The hyperpolarization-activated current (I(f)) plays an important role in determining the spontaneous rate of cardiac pacemaker cells. The automatic rhythmicity also exists in working cells of embryonic heart, therefore we studied developmental changes in functional expression and beta-adrenergic regulation of I(f) in embryonic mouse heart. The expression of I(f) is high in early developmental stage (EDS) (10.5 d after coitus) ventricular myocytes, low in intermediate developmental stage (IDS) (13.5 d) atrial or ventricular myocytes and even lower in late developmental stage (LDS) (16.5 d) atrial or ventricular myocytes, indicating that these cells of the EDS embryonic heart have some properties of pacemaker cells. Beta-adrenergic agonist isoproterenol (ISO) stimulates I(f) in LDS but not in EDS cardiomyocytes, indicating that the beta-adrenergic regulation of I(f) is not mature in EDS embryonic heart. But forskolin (a direct activator of adenylate cyclase) and 8-Br-cAMP (a membrane-permeable analogue of cAMP) increase the amplitude of I(f) in EDS cells, indicating that adenylate cyclase and cAMP function fairly well at early stage of development. Furthermore, the results demonstrate that I(f) is modulated by phosphorylation via cAMP dependent PKA both in EDS and LDS cells.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2002

[Determination of silicon, manganese and magnesium in cast iron by atomic emission spectrometry].

A spectrograph with high voltage spark source, once pre-burned and continuous photography was used for the quantitative determination of Silicon, Manganese and Magnesium in cast iron. The experimental conditions were optimized including the control of pre-burning time, plate moving rate, slit height of the blackness measuring, the selection of electrode material, the distance between the electrodes, shape of the electrode and the diminution of interferences. The determination range of contents (w/w) are 0.010%-0.090% for Mg, 1.50%-3.50% for Si and 0.40%-1.10% for Mn. The relative standard deviations are 10.4%, 1.9% and 3.0% for Mg, Si, and Mn, respectively.

English Abstract↗

PubMed1999

Epstein-Barr Virus Encoded Latent Membrane Protein 1 Increases Expression of Immunoglobulin kappa Light Chain through NFkappaB in a Nasopharyngeal Carcinoma Cell Line.

NFkappaB activity analysis was performed with pNFkappaB-luc reporter plasmid. Expression of NFkappaB in nuclear and expression of Igkappa in intact cells were analyzed by Western Blot to identify whether Epstein-Barr virus encoded latent membrane protein 1 (LMP1) increases the expression of immunoglobulin kappa light chain through NFkappaB signal transduction pathway in nasopharyngeal carcinoma. Results showed that LMP1 could increase NFkappaB activity and promote the accumulation of NFkappaB p65 in nucleus, and LMP1 also increased Igkappaexpression. In addition, phosphorothioate oligonucleotides to antisense NFkappaB p65 and p50 inhibited the Igkappaexpression. These imply that LMP1 can regulate Igkappa expression via NFkappaB signal transduction pathway in nasopharyngeal carcinoma.

Journal Article↗

PubMed1999

Doxycycline Dependent Expression of Epstein-Barr Virus Latent Membrane Protein 1 with Tet Regulating System in Nasopharygeal Carcinoma Cell Line.

Latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) plays a vital role in cell transformation and the nasopharygeal carcinoma (NPC) is highly related to EBV infection. To elucidate whether LMP1 exerts oncogenic effect in NPC and its possible mechanism, a dual-stable LMP1 integrated NPC cell line with Tet-on regulating system were established. Results revealed that expression of LMP-1 could be regulated by Tet system when NPC cell line HNE(2) served as receipt cell, and doxycycline could increase this expression by about 10 fold. Therefore, it is possible that different level expression of LMP-1 results in its different biological functions and various efforts on nasopharyngeal carcinogenesis.

Journal Article↗