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Biomedical subjects

Z M Wang

Publications and source records attributed to Z M Wang.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Methodological studies on quantitative determination of beta-eudesmol in Atractylodes lancea (thunb.) DC].

OBJECTIVE: To establish methodologically a method for quantitative determination of beta-eudesmol in Atractylodes lancea. METHOD: GC, column: 3 mm x 2 m; stationary phase; 15% QF-1; support: Chromosorb WAW(60-80 mesh); detector: hydrogen flame ionization detector; injection chamber temperature: 210 degrees C; column temperature: 174 degrees C; carrier gas: N2:50 ml.min-1, air: 49 kPa, H2:58.8 kPa; sensibility range: 10(2) x 64; chart speed: 2.5 mm.min-1. RESULT: Average recovery ratio is 100.7% (n = 5). CONCLUSION: This method can be used to control the quality of A. lancea.

Atractylodes↗
PubMed2000

[Detection of HPV-DNA and humoral immunity in juvenile laryngeal papilloma].

OBJECTIVE: To study HPV infection route and pathogenesis of juvenile laryngeal papilloma(JLP). METHOD: HPV-DNA of JLP was detected with PCR and PCR product dot blot hybridization. Serum Ig and complement 3(C3) was detected with nephelometry. RESULT: HPV total positive rate in JLP was 95%(19/20). HPV6 was 55%(11/20). HPV11 was 30%(6/20), and HPV6 + 11 was 10%(2/20). Serum IgG, IgA, IgM and C3 of JLP were normal, no significant difference between JLP and the control group(P > 0.05). CONCLUSION: HPV6 infection of JLP was in the majority. And the type was consistent with the type of female genital organ pointed condyloma. Humoral immunity was negligible in HPV infection. Pathologic picture of different HPV type infection was identical.

Child↗
PubMed2000

[Distribution of cholinergic efferent vestibular neurons].

OBJECTIVE: To investigate the effect and distribution of cholinergic efferent vestibular neurons in normal wistar rat. METHOD: HPR retrograde tracer and Immunocytochemical techniques were used. RESULT: Results show that AchT immunoreactive neurons locate in dorsolateral and dorsomedial to genu of the facial. Few neurons scatter in the parvocellular nucleus. CONCLUSION: As a neural transmitter, acetylcholine distribute in efferent vestibular neurons and play an important role.

Animals↗
PubMed2000

[Comparisons of auditory event-related potential P300 recorded with active and passive modes].

OBJECTIVE: To study the responsibilities and the clinical applications of auditory event-related response P300 recorded with active and passive modes in normal young adults. METHOD: P300s were recorded with active and passive modes, that is, to count and not to count the numbers of target stimuli during measuring respectively, in young adults as subjects. The waveforms, latencies and amplitudes of P300 were analyzed. RESULT: The resemble P300 in waveform and responsibility could be recorded with active and passive mode. There were some differential responsibilities between active and passive recording modes, which the latencies in active mode were shorter than the ones in passive mode, the amplitude of N1-P2 in active mode was lower than the one in passive mode, nevertheless, the amplitude of N2-P3 in active mode was significantly higher than the one in passive mode. CONCLUSION: The resemble P300 in waveform and responsibility could be recorded with active and passive mode. The differences of latencies and amplitudes between two modes demonstrated that the responsibility of P300 was related to the recognition process of auditory center. On the other hand, the passive recording mode of P300 is a way to measure for the uncooperative subjects.

Acoustic Stimulation↗
PubMed2000

[Effect of intranasal treatment with capsaicin on polyp recurrence after polypectomy and ethmoidectomy].

OBJECTIVE: To evaluate the influence of polypectomy and anterior ethmoidectomy associated with intranasal applications of capsaicin on the recurrence of nasal polyps. METHOD: Fifty one patients (19 females, 32 males, mean age 43) undergoing polypectomy and anterior ethmoidectomy were included in the study. In 29 patients, a cotton pellet soaked with capsaicin (3 x 10(-6) mol, dissolved in 70% ethanol) was left into the middle meatus for 20 min under local anaesthesia. As a control group, 22 patients were treated with the capsaicin vehicle alone (70% ethanol). All patients studied received the intranasal capsaicin or vehicle treatment once a week for 5 weeks. The clinical objective examination and the subjective evaluation of nasal obstruction, rhinorrhea were recorded by means of a visual analogic scale graded from 0 to 4 throughout the study. RESULT: Patients treated with intranasal capsaicin application reported 9 months later and 55 months later separately, a marked reduction of their subjective evaluation of nasal obstruction when compared to the pretreatment evaluation (P < 0.01). In contrast, patients treated with the capsaicin vehicle alone did not have any significant improvement of their subjective evaluation of nasal obstruction. Subjective rhinorrhea was not modified by either treatment. Of 29 patients with capsaicin treatment, 25 (86.2%) patients (9 months later) and 20 (69%) patients (55 months later) showed satisfactory result, compared to 10 (45.4%) patients and 8 (36.4%) patients separately in the control group, the difference was significant (P < 0.01). CONCLUSION: Intranasal capsaicin application can reduce polyp recurrence and nasal obstruction after polypectomy and ethmoidectomy.

Administration, Intranasal↗
PubMed1999

Cloning and characterization of a bifunctional RelA/SpoT homologue from Mycobacterium tuberculosis.

A 2.2kb relA/spoT homologue was isolated from Mycobacterium tuberculosis (Mtb) genomic DNA by PCR-amplification. The Mtb gene encodes a protein of 738 amino acid residues, and is flanked upstream by an ORF that is highly similar to the apt gene, and downstream by an ORF that is highly similar to the cypH gene. This dual function Mtb homologue belongs to the relA/spoT family of genes that mediate the stringent response by regulating the synthesis and degradation of guanosine 3',5'-bis(diphosphate) (ppGpp) and pppGpp. In vitro biochemical data indicate that purified RelMtb is a ribosome- and tRNA-independent ATP:GTP/GDP/ITP 3'-pyrophosphoryltransferase. Additionally, purified RelMtb is an Mn2+-dependent, ribosome and tRNA-independent, (p)ppGpp 3'-pyrophosphohydrolase. These reactions were also assessed in vivo in E. coli deleted in both the relA and spoT genes, which generates a (p)ppGpp0 phenotype. RelMtb can suppress this phenotype and can generate more (p)ppGpp than relA in the wild type E. coli control.

Amino Acid Sequence↗
PubMed1999

Insulin-like growth factor-1 enhances rat skeletal muscle charge movement and L-type Ca2+ channel gene expression.

1. We investigated whether insulin-like growth factor-1 (IGF-1), an endogenous potent activator of skeletal muscle proliferation and differentiation, enhances L-type Ca2+ channel gene expression resulting in increased functional voltage sensors in single skeletal muscle cells. 2. Charge movement and inward Ca2+ current were recorded in primary cultured rat myoballs using the whole-cell configuration of the patch-clamp technique. Ca2+ current and maximum charge movement (Qmax) were potentiated in cells treated with IGF-1 without significant changes in their voltage dependence. Peak Ca2+ current in control and IGF-1-treated cells was -7.8 +/- 0.44 and -10. 5 +/- 0.37 pA pF-1, respectively (P < 0.01), whilst Qmax was 12.9 +/- 0.4 and 22.0 +/- 0.3 nC microF-1, respectively (P < 0.01). 3. The number of L-type Ca2+ channels was found to increase in the same preparation. The maximum binding capacity (Bmax) of the high-affinity radioligand [3H]PN200-110 in control and IGF-1-treated cells was 1.21 +/- 0.25 and 3.15 +/- 0.5 pmol (mg protein)-1, respectively (P < 0.01). No significant change in the dissociation constant for [3H]PN200-110 was found. 4. Antisense RNA amplification showed a significant increase in the level of mRNA encoding the L-type Ca2+ channel alpha1-subunit in IGF-1-treated cells. 5. This study demonstrates that IGF-1 regulates charge movement and the level of L-type Ca2+ channel alpha1-subunits through activation of gene expression in skeletal muscle cells.

Animals↗
PubMed1999

The 2.2 A crystal structure of human chymase in complex with succinyl-Ala-Ala-Pro-Phe-chloromethylketone: structural explanation for its dipeptidyl carboxypeptidase specificity.

Human chymase (HC) is a chymotrypsin-like serine proteinase expressed by mast cells. The 2.2 A crystal structure of HC complexed to the peptidyl inhibitor, succinyl-Ala-Ala-Pro-Phe-chloromethylketone (CMK), was solved and refined to a crystallographic R-factor of 18.4 %. The HC structure exhibits the typical folding pattern of a chymotrypsin-like serine proteinase, and shows particularly similarity to rat chymase 2 (rat mast cell proteinase II) and human cathepsin G. The peptidyl-CMK inhibitor is covalently bound to the active-site residues Ser195 and His57; the peptidyl moiety juxtaposes the S1 entrance frame segment 214-217 by forming a short antiparallel beta-sheet. HC is a highly efficient angiotensin-converting enzyme. Modeling of the chymase-angiotensin I interaction guided by the geometry of the bound chloromethylketone inhibitor indicates that the extended substrate binding site contains features that may generate the dipeptidyl carboxypeptidase-like activity needed for efficient cleavage and activation of the hormone. The C-terminal carboxylate group of angiotensin I docked into the active-site cleft, with the last two residues extending beyond the active site, is perfectly localized to make a favorable hydrogen bond and salt bridge with the amide nitrogen of the Lys40-Phe41 peptide bond and with the epsilon-ammonium group of the Lys40 side-chain. This amide positioning is unique to the chymase-related proteinases, and only chymases from primates possess a Lys residue at position 40. Thus, the structure conveniently explains the preferred conversion of angiotensin I to angiotensin II by human chymase.

Amino Acid Chloromethyl Ketones↗
PubMed1999

Calcium regulates L-type Ca2+ channel expression in rat skeletal muscle cells.

Primary skeletal muscle cells were cultured in a normal- (1.8 mM) or high- (4.8 mM) Ca2+ culture medium to determine whether Ca2+ modulates the number of L-type Ca2+ channels. Skeletal myoballs cultured in a normal medium showed, when exposed to a high extracellular [Ca2+], ([Ca2+]e) a transient increase in intracellular [Ca2+] ([Ca2+]i) from a resting concentration of 60 to 160 nM. By day 3, however, when the experiments were made, [Ca2+]i no longer differed from control (pre-exposure to high Ca2+). The maximum charge movements in myoballs incubated in 1.8 and 4.8 mM were 16.4+/-1.05 (n=56) and 24.1+/-1.18 nC/microF (n=58; P<0.01), respectively, and peak Ca2+ currents at 20 mV were -10.8+/-1.09 (n=46) and -12.8+/-0.75 nA/microF (n=82), respectively (P>0.05). The tail current amplitudes in 1.8 and 4.8 mM Ca2+-treated cells were -9.3+/-1.23 and -14.2+/-1.37 nA/microF (P<0.05), respectively, at 10 mV and -15.3+/-1.76 and -23.6+/-2.02 nA/microF (P<0.05), respectively at 60 mV. The maximum binding of [3H]PN200-110 (a radioligand specific for L-type Ca2+ channel alpha1 subunits) in myoballs cultured in 1.8 and 4.8 mM [Ca2+]e was 1.34+/-0.23 and 3.2+/-0.63 pmol/mg protein (n=8; P<0.02), respectively. The increase in [Ca2+]i associated with the increases in charge movements, tail currents and the number of L-type Ca2+ channel alpha1 subunits in skeletal muscle cells cultured in high [Ca2+]e support the concept that extracellular Ca2+ influx modulates the expression of L-type Ca2+ channels in skeletal muscle cells.

Animals↗
PubMed1999

Patch-clamp recording of charge movement, Ca2+ current, and Ca2+ transients in adult skeletal muscle fibers.

Intramembrane charge movement (Q), Ca(2+) conductance (G(m)) through the dihydropyridine-sensitive L-type Ca(2+) channel (DHPR) and intracellular Ca(2+) fluorescence (F) have been recorded simultaneously in flexor digitorum brevis muscle fibers of adult mice, using the whole-cell configuration of the patch-clamp technique. The voltage distribution of Q was fitted to a Boltzmann equation; the Q(max), V(1/2Q), and effective valence (z(Q)) values were 41 +/- 3.1 nC/microF, -17.6 +/- 0.7 mV, and 2.0 +/- 0.12, respectively. V(1/2G) and z(G) values were -0.3 +/- 0.06 mV and 5.6 +/- 0.34, respectively. Peak Ca(2+) transients did not change significantly after 30 min of recording. F was fit to a Boltzmann equation, and the values for V(F1/2) and z(F) were 6.2 +/- 0.04 mV and 2.4, respectively. F was adequately fit to the fourth power of Q. These results demonstrate that the patch-clamp technique is appropriate for recording Q, G(m), and intracellular [Ca(2+)] simultaneously in mature skeletal muscle fibers and that the voltage distribution of the changes in intracellular Ca(2+) can be predicted by a Hodgkin-Huxley model.

Animals↗
PubMed1999

Modeling the relationship between concurrent epicardial action potentials and bipolar electrograms.

A signal analysis approach to building the relationship between concurrent epicardial cell action potentials (AP's) and bipolar electrograms is presented. Wavelet network, one nonlinear black-box modeling method, is used to identify the relationship between cell AP's and bipolar electrocardiograms. The electrical signals were simultaneously measured from the epicardium of isolated Langendorff-perfused rabbit hearts during three different rhythm conditions: normal sinus rhythm (NSR), normal sinus rhythm after ischemia (NSRI), and ventricular fibrillation (VF). For NSR and NSRI, the proposed modeling method successfully captures the nonlinear input-output relationship and provides an accurate output, but the method fails in case of VF. This result suggests that a time-invariant nonlinear modeling method such as wavelet network is not appropriate for VF rhythm, which is thought to be time-varying as well as chaotic, but still useful in detection of VF. A new arrhythmia detection algorithm, with potential application in implantable devices, is proposed for identifying the time of rhythmic bifurcation.

Action Potentials↗
PubMed1998

Endogenous E2F-1 promotes timely G0 exit of resting mouse embryo fibroblasts.

Much evidence strongly suggests a positive role for one or more E2F species in the control of exit from G0/G1. Results described here provide direct evidence that endogenous E2F-1, as predicted, contributes to progression from G0 to S. By contrast, cycling cells lacking an intact E2F-1 gene demonstrated normal cell cycle distribution. Therefore, E2F-1 exerts a unique function leading to timely G0 exit of resting cultured primary cells, while at the same time being unnecessary for normal G1 to S phase progression of cycling cells.

Animals↗
PubMed1998

Altered inotropic response of endothelin-1 in cardiomyocytes from rats with isoproterenol-induced cardiomyopathy.

OBJECTIVE: The positive inotropic effect of endothelin-1 (ET-1) on normal myocardial contraction may be altered in pathological states. The purpose of this study was to assess the direct effect of ET-1 on cardiomyocyte performance and its cellular mechanism in congestive heart failure (CHF). METHODS: We measured the plasma levels of ET-1 and compared the effects of ET-1 (10(-10)-10(-8) M) on contractile performance and the [Ca2+]i transient in the myocytes of left ventricles (LV) from 15 age-matched normal adult rats and 15 rats with isoproterenol (ISO)-induced CHF. RESULTS: With CHF, the plasma levels of ET-1 (19.7 +/- 6.3 vs. 4.1 +/- 0.5 fmol/ml, p < 0.05) were markedly elevated. In normal myocytes, superfusion of ET-1 caused significant increases in the systolic amplitude (SA, 8-16%) and the peak velocity of shortening (dL/dtmax, 20-35%; p < 0.01) without causing a change in the peak [Ca2+]i transient. In contrast, in myocytes from CHF rats, ET-1 produced significant reductions in SA (9-13%) and in the velocity of relengthening, dR/dtmax (10-14%; p < 0.05). The myocytes' dR/dtmax also decreased by 8-10% (p < 0.05). These changes were associated with a significant decrease in the peak [Ca2+]i transient (20-23%, p < 0.01). These responses to ET-1 were abolished by the incubation of myocytes with an ETA receptor antagonist (BQ123) or a protein kinase C (PKC) inhibitor (H-7 or staurosporine). CONCLUSION: ISO-induced CHF is associated with elevated plasma ET-1 and an altered cardiomyocyte response to ET-1. After CHF, ET-1 produces a direct depression of cardiomyocyte contractile performance that is associated with a significant decrease in the peak [Ca2+]i transient. These effects are likely to be mediated through ETA receptors and involve the PKC pathway.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1998

Six-compartment body composition model: inter-method comparisons of total body fat measurement.

OBJECTIVE: To compare 16 currently used total body fat methods to a six-compartment criterion model based on in vivo neutron activation analysis. DESIGN: Observational, inter-method comparison study. SUBJECTS: Twenty-three healthy subjects (17 male and 6 female). MEASUREMENTS: Total body water (TBW) was measured by tritium dilution; body volume by underwater weighing (UWW); total body fat and bone mineral by dual-energy X-ray absorptiometry (DXA), total body potassium (TBK) by whole-body 40K counting; total body carbon, nitrogen, calcium, phosphorus, sodium and chlorine by in vivo neutron activation analysis; skinfolds/circumferences by anthropometry (Anth); and resistance by single-frequency bioimpedance analysis (BIA). RESULTS: The average of total body fat mass measurements by the six-compartment neutron activation model was 19.7+/-10.2kg (mean+/-s.d.) and comparable estimates by other methods ranged from 17.4-24.3 kg. Although all 16 methods were highly correlated with the six-compartment criterion model, three groups emerged based on their comparative characteristics (technical error, coefficient of reliability, Bland-Altman analysis) relative to criterion fat estimates, in decreasing order of agreement: 1. multi-compartment model methods of Baumgartner (19.5+/-9.9 kg), Heymsfield (19.6+/-9.9 kg), Selinger (19.7+/-10.2 kg) and Siri-3C (19.6+/-9.9 kg); 2. DXA (20.0+/-10.8 kg), Pace-TBW (18.8+/-10.1 kg), Siri-2C (20.0+/-9.9 kg), and Brozek-UWW (19.4+/-9.2 kg) methods; and 3. Segal-BIA (17.4+/-7.2 kg), Forbes-TBN (21.8+/-10.5 kg), Durnin-Anth (22.1+/-9.5 kg), Forbes-TBK (22.9+/-11.9 kg), and Steinkamp-Anth (24.3+/-9.5 kg) methods. CONCLUSION: Relative to criterion fat estimates, body composition methods can be organized into three groups based on inter-method comparisons including technical error, coefficient of reliability and Bland-Altman analysis. These initial groupings may prove useful in establishing the clinical and research role of the many available fat estimation methods.

Absorptiometry, Photon↗
PubMed1998

[A comparative study of apical sealing ability on filling techniques for curved canal of posterior teeth]

A comparison of apical leakage produced by three preparation technique and two obrutation methods was done in this article.The fine curved canals were prepared with routine prepartion technique,ultrasonic technique,step-back technique and filled with traditional lateral condensation,warm gutta-percha lateral condensation separately.The result showed that the apical sealing ability of warm gutta-percha lateral condensation was superior to traditional lateral condensation.It could remedy the defect of irregular canal shape of fine curved canal preapred with routine technique and ultrasonic technique in some degree by the improvement of apical sealing ability.

Journal Article↗
PubMed1997

Role of the P6-P3' region of the serpin reactive loop in the formation and breakdown of the inhibitory complex.

Serpins have a large external peptide loop known as the reactive loop. Part of the reactive loop functions as the primary recognition site for target proteases; however, the complete role of the reactive loop in determining serpin specificity is unclear. In the current study, we investigated the reactive loop region that could potentially interact with the extended binding site of target proteases; the P6-P3' region. We utilized a reactive loop switching strategy to determine the extent to which the inhibitory activity of alpha-1-protease inhibitor (PI) against human neutrophil elastase (HNE) could be transferred to alpha-1-antichymotrypsin (ACT), a serpin that does not inhibit HNE. A series of ACT-PI chimeras were constructed in which segments of increasing length taken from the P6-P3' region of PI replaced the corresponding residues of ACT. The effectiveness of each chimera as an inhibitor of HNE was assessed by measuring (1) the rate of inhibitory complex formation and (2) the rate of complex breakdown (complex stability). Although all the ACT-PI chimeras were fully functional against chymotrypsin-like proteases, the series of chimeras showed no consistent progress toward the production of an inhibitor with the inhibitory properties of PI. The most rapid complex formation and most stable complexes were observed for chimeras with the P3-P1 residues of PI, whereas extending the replacement region to the P6 residue resulted in a considerable decrease in both inhibitory parameters. In order to study two additional features of the PI reactive loop that may play a role in the presentation of the P6-P3' region to HNE, we constructed variants that contained a P4' proline and deleted the P6'-P9' residues. Changes on the prime side appeared to have little effect on rates of inhibition or complex stability. Overall, even the most effective chimeras demonstrated an inhibition rate constant at least 60-fold less than that observed for PI inhibition of HNE and the most long lived chimera-HNE complexes broke down more rapidly than PI-HNE complexes. These results indicate that residues in the reactive loop region predicted to contact a specific target protease cannot fully transfer inhibitory activity from one serpin to another, suggesting that specific reactive loop-serpin body and serpin body-protease body interactions play a significant role in determining serpin inhibitory activity against target proteases.

Amino Acid Sequence↗
PubMed1997

Mutation of the protein kinase C phosphorylation site on rat alpha1 Na+,K+-ATPase alters regulation of intracellular Na+ and pH and influences cell shape and adhesiveness.

The enzyme Na+,K+-ATPase creates the transmembrane Na+ gradient that is of vital importance for functioning of all eukaryotic cells. Na+, K+-ATPase can be phosphorylated by protein kinase A (PKA) and protein kinase C (PKC), and these sites of phosphorylation have been identified. In the present study, we have examined the physiological significance of PKC phosphorylation of rat Na+,K+-ATPase. In COS cells transfected with wild type rat Na+,K+-ATPase alpha1, intracellular Na+ was higher and pH was lower than in cells transfected with rat Na+,K+-ATPase alpha1 in which the PKC phosphorylation site, Ser-23, had been mutated into alanine. Phorbol dibutyrate inhibited Na+,K+-ATPase-dependent ATP hydrolysis and Rb+ uptake in cells expressing wild type Na+,K+-ATPase but not in cells expressing S23A Na+,K+-ATPase. Cells expressing the S23A mutant had a more rounded appearance and attached less well to fibronectin than did untransfected cells or cells transfected with wild type rat Na+, K+-ATPase alpha1. These results indicate a functional role for PKC-mediated phosphorylation of rat Na+,K+-ATPase alpha1 and suggest a connection between this enzyme and cell adhesion.

Animals↗