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Biomedical subjects

D Y Hu

Publications and source records attributed to D Y Hu.

At least 19 recordsLinked to original sources
PubMed2001

A cross-cultural comparison of dental health attitudes and behaviour among freshman dental students in Japan, Hong Kong and West China.

OBJECTIVE: To clarify the differences in dental health attitudes/behaviour among freshman dental students. DESIGN: Cross-cultural differences. SETTING: Japan, Hong Kong and West China. PARTICIPANTS AND METHODS: The original version of the Hiroshima University-Dental Behavioural Inventory (HU-DBI) was written in Japanese. After testing the validity of both English and Chinese versions, the original version of the HU-DBI was administered to 58 freshman Japanese dental students, the English version to 43 Hong Kong Chinese peers and the Chinese version to 39 West Chinese peers. RESULTS: Significant cultural differences were found for 16 items out of 20. The most striking result was that the Japanese students were more likely to have used a dye to see how clean their teeth were, compared to their Chinese peers (P<0.001). The Chinese students were less likely to have a belief that they could clean their teeth well without using toothpaste (P<0.001), whereas higher percentages of the Chinese students worried about having bad breath (P<0.001). A higher percentage of the Hong Kong students reported that they regularly checked their teeth in a mirror than did their West Chinese or Japanese peers (P<0.05). CONCLUSIONS: There were considerable differences in dental health attitudes/behaviour among freshman dental students in the three cultural groups.

Adolescent↗
PubMed2001

[Hemorrhagic shock induces changes in large-conductance Ca(2+) dependent K+ channel activity in mesenteric arterial smooth muscle cells of rats].

The purpose of the present study was to detect changes in the activity of large-conductance Ca(2+)activated K(+) channel (BK(Ca)) during hemorrhagic shock (HS) in mesenteric arterial vascular smooth muscle cells using inside-out patches. The HS rat model was produced with withdrawing blood from the femoral artery. The results showed that the BK(Ca) activity was inhibited with decreased open probability (P(o)) and single-channel conductance. The decrease of P(o) resulted from an increase of the close time constant (tau(cs)) in the compensatory stage of HS, i.e.the term of hyperresponse of the muscle to norepinephrine (NE) (HS lasted for about 40 min). During the decompensation stage of HS, i.e. the period of hyporesponse to NE (HS developed for 3 h), the BK(Ca) activity was enhanced with the increase in single-channel conductance and P(o) which was a result of a decrease in tau(cs).

Animals↗
PubMed2000

Effects of MCI-154, a calcium sensitizer, on cardiac dysfunction in endotoxic shock in rabbits.

This study was designed to observe the effects of MCI-154, a calcium sensitizer, on cardiac dysfunction after endotoxic shock in rabbits. Ten hours after the rabbits were given injection of 1.0 mg/kg endotoxin (Escherichia coli, O111:B4) via marginal ear veins, 0.1 mg/kg MCI-154 was injected intravenously and then 50 mL/kg normal saline (NS) + 0.1 mg/kg MCI-154 was infused continuously at a rate of 0.7 mL/min. During this process, the parameters of cardiac function were measured. It was found that 10 h after the endotoxin injection, heart rate (HR) was increased significantly while the mean arterial blood pressure (MAP), left ventricular systolic pressure (LVSP), isovolumetric pressure (IP), myocardial contractility (MC), and the area of p-dp/dt(max) vector loop (Lo) all were markedly decreased. Treatment with 50 mL/kg NS alone had slight effects on these parameters. On the contrary, LVSP, IP, MC, and Lo all were increased significantly while HR was not obviously changed and left ventricular end-diastolic pressure (LVEDP) was reduced remarkably following MCI-154 administration in endotoxic shock rabbits. The parameters of myocardial contractility were improved nearly to the values in sham shock group and were markedly higher than that in NS alone-treated group. It can be concluded that MCI-154 can exert significant therapeutic effects on cardiac dysfunction after endotoxic shock, for it improves cardiac function, dilates peripheral blood vessels, and slightly affects HR.

Animals↗
PubMed2000

Effects of MCI-154, a calcium sensitizer, on cardiac function in endotoxemic rabbits.

AIM: To observe the effects of MCI-154, a calcium sensitizer, on cardiac function after endotoxic shock. METHODS: The rabbits were intravenously injected with MCI-154 0.1 mg.kg-1 at 10 h after the administration of endotoxin 1.0 mg.kg-1, followed by a continuous infusion of normal saline (NS) 50 mL.kg-1 + MCI-154 0.1 mg.kg-1. During this process, the parameters of cardiac function were measured. RESULTS: Ten hours after the endotoxin injection, heart rate (HR) increased noticeably while the mean arterial blood pressure (MAP), left ventricular systolic pressure (LVSP), isovolumetric pressure (IP), myocardial contractility (MC), and the area of p-dp/dtmax vector loop (Lo) were all markedly decreased. Treatment with NS 50 mL.kg-1 alone had slight effects on these parameters. LVSP, IP, MC, and Lo were all markedly increased while HR did not obviously change and left ventricular end-diastolic pressure (LVEDP) was reduced markedly following MCI-154 administration in endotoxic shock rabbits. The parameters of MC were improved nearly to the same values as in sham shock group and were markedly higher than in NS treated group. CONCLUSION: MCI-154 exerts remarkable therapeutic effects on cardiac dysfunction after endotoxic shock.

Animals↗
PubMed2000

Effect of MCI-154, a calcium sensitizer, on calcium sensitivity of myocardial contractile system in endotoxemic rats.

AIM: To investigate the effect of MCI-154 on calcium sensitivity of myocardial contractile system in endotoxemic rats. METHODS: Skinned right ventricular papillary muscles from endotoxemic rats were prepared by saponin 500 mg/L. Forces of the skinned muscles were recorded when they were activated sequentially by different concentrations of Ca2+ with or without cardiotonic agents. The tension-pCa relationship and pCa50 of the skinned fibers were taken as the index of Ca2+ sensitivity of myocardial contractile system. RESULTS: The maximal Ca(2+)-activated tension (Tmax) was lower, and pCa50 was reduced in endotoxemia group as compared with those in sham control group. Milrinone 50 mumol/L could not counteract the above abnormalities. However, after MCI-154 10 mumol/L was added, the Tmax and pCa50 were increased to an extent similar to that of sham control group and significantly higher than those of endotoxemia group and endotoxemia + milrinone group. Furthermore, such effects of MCI-154 were concentration-dependent. CONCLUSION: The Ca2+ sensitivity of cardiac contractile system in endotoxemic rats is decreased. MCI-154 can reverse the decreased sensitivity and increase Tmax of myocardial muscles from endotoxemic rats.

Animals↗
PubMed1999

Dental caries status and treatment needs of 12-13-year-old children in Sichuan Province, southwestern China.

OBJECTIVE: To update information on the dental caries status of children living in the Southwestern part of China for planning appropriate dental care services and to obtain information on caries level in rural areas. METHOD: All first year students studying in seven secondary schools (two in urban, two in peri-urban and three in rural areas) in Sichuan Province were surveyed. The students were clinically examined in their schools using procedures and diagnostic criteria recommended by the World Health Organization. RESULTS: A total of 1,542 children, 12-13 years of age, were examined of which 660, 519 and 363 were from the urban, peri-urban and rural schools respectively. The prevalence of caries experience was highest in urban children (30%), followed by peri-urban children (21%) and lowest in rural children (13%). The respective DMFT index scores for the urban, peri-urban and rural children were 0.62, 0.38 and 0.18. The differences were statistically significant (P < 0.001). The major component of the DMFT index was untreated decay (DT) in all three areas. CONCLUSION: There was a clear trend of increasing prevalence and severity of dental caries in children as the survey sites moved from rural, through peri-urban to urban areas. Thus, estimates of dental caries in Chinese child populations of this age based on surveys conducted in urban areas will probably lead to gross over-estimation as over 80% of the people live in rural areas.

Adolescent↗
PubMed1998

Effects of metallothionein on action potentials of anoxic and reoxygenated papillary muscles of guinea pigs.

AIM: To study anti-arrhythmic effects of metallothionein (MT). METHODS: Standard microelectrode technique was used to study the effects of MT on action potentials (AP) in anoxic and reoxygenated papillary muscles of guinea pigs. RESULTS: MT (0.02 mmol.L-1) had no effects on AP of the normal papillary muscles; when the muscles were exposed to ischemic solution without MT, there was a marked shortening of action potential duration (APD) at 20%, 50%, and 90% of repolarization (APD20, APD50, APD90) from 82 +/- 7 to 37 +/- 7, 131 +/- 35 to 63 +/- 11, and 167 +/- 12 to 100 +/- 19 ms, respectively, (P < 0.01); and an obvious reduction of resting potential (RP), action potential amplitude (APA), and the maximal upstroke velocity of phase 0 (Vmax) from -92 +/- 9 to -63 +/- 12 mV, 135 +/- 13 to 80 +/- 8 mV, and 286 +/- 55 to 164 +/- 42 V.s-1, respectively (P < 0.01). However, in the presence of MT, the AP parameters (RP, APA, and Vmax) changed from -63 +/- 2 to -82 +/- 1 mV, 80 +/- 8 to 104 +/- 25 mV, and 164 +/- 42 to 237 +/- 43 V.s-1, respectively, (P < 0.01), except that APD20, APD50, and APD90 shortened further from 37 +/- 7 to 12 +/- 3, 63 +/- 11 to 28 +/- 7, and 100 +/- 19 to 82 +/- 11 mV, respectively (P < 0.01). MT decreased the incidence of automaticity during reoxygenation from 91% to 33%. CONCLUSION: MT possesses a calcium regulatory property.

Action Potentials↗
PubMed1997

The importance of delta and kappa opioid receptors in the property of thyrotropin-releasing hormone against hemorrhagic shock.

Many studies have demonstrated that thyrotropin-releasing hormone (TRH) produces various beneficial effects in the treatment of shock. TRH has been proposed to reverse the cardiovascular depression of endogenous opioid peptides. Nevertheless, it remains unknown whether opioid receptors are truly involved in this process. We designed experiments to study the importance of delta and kappa opioid receptors in the beneficial effects of TRH in hemorrhagic shock in rabbits and on opiate receptors following hemorrhagic shock in rats. The results indicated that TRH (50 micrograms, i.c.v.) significantly improved the mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), and the maximal rate of ventricular systolic pressure changes (+/- dp/dtmax) during hemorrhagic shock in rabbits. This TRH effect was abolished by pretreatment with ICI174,864 (50 micrograms, i.c.v.), a highly selective delta opioid receptor antagonist, but not by pretreatment with nor-binaltorphimine (Nor-BNI, 50 micrograms, i.c.v.), a highly selective kappa opioid receptor antagonist. The maximal binding capacity (Bmax) of brain delta and kappa opioid receptors significantly increased following hemorrhagic shock, but the receptor affinity (Kd) did not change. TRH (5 mg/kg, i.v.) decreased the number (Bmax) of brain delta opioid receptors significantly, but it did not influence the receptor affinity. TRH did not influence the Bmax or affinity of brain kappa opioid receptors. These findings suggest that opioid receptors play an important role in mediating the antishock property of TRH. TRH-induced down-regulation of the number of brain opioid receptors may be one of the important mechanisms by which TRH exercises its protective effects in the treatment of shock.

Animals↗
PubMed1997

Electrophysiologic effect of enalapril on guinea pig papillary muscles in vitro.

AIM: To study the direct effect of enalapril on cellular electrophysiology of myocardium. METHODS: Conventional microelectrodes technique was used to record the action potentials (AP) of guinea pig papillary muscles. RESULTS: Enalapril caused an increase of the AP amplitude (APA) and the resting potential (RP) in a concentration-dependent manner without any significant change of AP duration, Vmax and overshoot of AP. Superfusion of ouabain 0.5 mumol.L-1 reduced APA and RP, induced stable delayed after-depolarizations (DAD) at different basic cycle lengths (BCL) in a frequency-dependent manner. At BCL 200 ms, the amplitude of DAD was large enough to induce nonsustained triggered activity (TA). In additional presence of enalapril 10 mumol.L-1, the DAD amplitude at 500, 400, 300, and 200 ms were decreased from 5.3 +/- 2.3, 5.9 +/- 2.8, 7.4 +/- 2.1, and 8.9 +/- 1.3 to 2.6 +/- 0.7, 3.1 +/- 1.0, 3.7 +/- 1.5, and 5.3 +/- 1.1 (mV) respectively, all P < 0.01. The compensation intervals were increased in a similar frequency-dependent manner. The number of TA induced at BCL 200 ms was decreased from 3.6 +/- 0.7 to 0.8 +/- 0.2 (P < 0.05). CONCLUSION: Enalapril directly inhibits DAD and TA induced by ouabain through increasing RP and APA, which may contribute to its anti-arrhythmic effect.

Action Potentials↗
PubMed1997

[Epidemiological analysis on the rising of brucellosis prevalence in the area already under controlled].

An epidemiological analysis was made on the outbreak of brucellosis in Sui-de County, Shaanxi Province in 1995-1996. Result showed that it was one of the most serious brucellosis outbreaks since 1986 when national brucellosis under controlled critiria had been met in the province, and the number of cases was continuously spreading and growing. The incidence was up to 84.8 per 10(5) and the prevalence rate reached 17.5 percent. Patients had typical symptoms with bad conditions. Most all the cases were those who had vocations such as shepherds, etc. Patients' antibody titers were very high with the highest one approached 1:25,600. Two strains of B. melitensis, type III were isolated from the blood of patients.

Adolescent↗
PubMed1996

[Endothelin-stimulated proliferation of thoracic artery smooth muscle cells involves activation of mitogen-activated protein kinase].

Endothelin (ET) is a potent vasoconstrictor whose responses are mediated through a common G-protein coupled receptor. So far little is known concerning its potential mitogenic capacity. In the present study, experiments were conducted to determine the role of mitogen-activated protein kinase (MAPK) activation in the rabbit thoracic artery smooth muscle cells (VSMC) in response to stimulation by ET-1. It was found that ET-1 produced concentration- and time-dependent increases in 3H-TdR incorporation and in MAPK activity of these cells. All the increases were inhibited by protein kinase C (PKC) inhibitors, such as Staurosporine (STP) and H-7 and by ETA receptor antagonist BQ123, but not by specific tyrosine kinase inhibitor Herbimycin A (Herb). Pre-treatment with PKC activator PMA (phorbol myristate acetate) for 24 h (PKC downregulation) significantly attenuated ET-1-induced MAPK activation. These results indicate that: (1) ET-1-stimulated proliferation of VSMC involves the activation of MAPK and (2) ET-1-induced MAPK activation is mediated through ETA receptor and PKC.

Animals↗
PubMed1995

[Localization value of intra-esophageal atrial pacing by modified digitus medius proportional unit].

The length of lead electrode which was eleven times the length of modified digitus medius proportional unit used for intra-esophageal atrial pacing on 86 patients was compared with the length lcm more or less than the lead length itself showed very significant difference in pacing threshold, which was low, adverse reaction was mild, the intra-esophageal P wave display was satisfactory. It could alleviate the patient's pain, and was easy to manipulate, practical, rapid and inexpensive in diagnosis and treatment of arrhythmia, rescuing indoor or outdoor emergency cases as well as monitoring operation.

Anthropometry↗
PubMed1995

Effects of thyrotropin-releasing hormone on myocardial adrenoceptors and dopaminergic receptors following hemorrhagic shock in the rat.

Although studies have indicated that thyrotropin-releasing hormone (TRH) produces various beneficial effects following low flow conditions, it remains unknown whether this agent has any salutary effect on myocardial alpha- and beta-adrenergic and dopaminergic (DA) receptors following hemorrhagic shock. To study this, rats (220-280 g) were bled to a mean arterial pressure of 40 mmHg and maintained for 1.5 h following shock. TRH or an equivalent volume of normal saline was administered. Receptor binding assay was carried out in myocardial plasma membrane preparations at 15 and 45 min after TRH administration. The results indicate that the maximal binding capacity (Bmax) of myocardial alpha- and beta-adrenergic receptors and their affinity decreased significantly following hemorrhage. The Bmax of DA receptors was also reduced, while the affinity was not significantly affected by hemorrhagic insult. Administration of TRH (5 mg/kg body wt) at 1.5 h after the onset of hemorrhage, however, markedly increased the Bmax of myocardial beta-adrenergic and DA receptors. The decreased affinity of beta-adrenoceptors observed in hemorrhaged animals was also improved with TRH treatment. TRH did not, however, significantly affect the altered Bmax and affinity of alpha-adrenoceptors following hemorrhagic shock. These results suggest that TRH-induced upregulation of beta-adrenoceptor and DA receptor binding capacity and the enhanced affinity of beta-adrenoceptors may be one of the mechanisms by which TRH produces the beneficial effects following hemorrhagic shock.

Animals↗
PubMed1994

The significance of anatomical variations of hepatic artery and multiple arterial supplies in embolization of liver tumors.

A new therapeutic measure-step by step-embolization of every feeding vessel in dealing with liver cancer has been proposed on the base of the following criteria after reviewing the coeliac and superior mesenteric arteriographies in 100 cases of liver cancer. The emphasis is put on: 1. Anatomic variation of hepatic arteries. 2. Multiple feeding vessels, and 3. The importance of the presence of stenosis after embolization and the formation of collateral circulation.

Adult↗
PubMed1994

[Multiple analysis of the factors influencing the result of tilt table test].

Ninety two patients with unexplained syncope and 52 normal controls without history of syncope were divided into three groups respectively. Baseline tilt table test (BTTT), multistage isoproterenol tilt table test (MITTT), and single stage isoproterenol tilt table test (SITTT) were performed in all of them. Logistics regression was used with the result of TTT as independent variable; dependent variables included sex, age, basal heart rate, basal blood pressure, the index of syncope (i) and the difference between basal heart rate and the rate before tilting (h12). The results were as follows: (1) According to the regression for the total population tested, the main factors influencing the result of TTT were i and h12 (P = 0.012 and P = 0.001). Similar result was found in the patient group (P = 0.052 and P = 0.032). (2) In the control group, sex and h12 were the predictors of the result (P = 0.090 and P = 0.016). It is concluded that: (1) The result of TTT is mainly affected by the frequency and degree of syncope, as well as by the use of isoproterenol; (2) Isoproterenol increases the sensitivity of TTT, but decreases the specificity; (3) Sex is probably an important factor affecting the result of TTT.

Adolescent↗