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Biomedical subjects

Z Z Lu

Publications and source records attributed to Z Z Lu.

At least 19 recordsLinked to original sources
PubMed2001

AIDS and sex education for young people in China.

Although China has had a rich sexual culture for thousands of years, Chinese people are usually unwilling to openly discuss issues of sex. Some parents are quite ignorant of the change in their children's sexual attitude and behaviour. In China today, adolescents are becoming much more sexually liberated. Premarital sex and unplanned pregnancies among teenagers are increasing. Sexually transmitted diseases (STD) including HIV/AIDS are also spreading rapidly. However, young people lack basic information on AIDS/STD and do not know how to protect themselves from these diseases or how to avoid unintended pregnancies. Several major youth peer education programmes in China are mentioned in this paper. Among them, a four-year programme entitled the Australian-Chinese AIDS/STD/Safer Sex Peer Education Programme for Youth, is discussed in some detail. The programme has so far reached over 40000 university and school students. Evaluation results show that the programme is effective in both significantly increasing students' knowledge about AIDS/STDs and changing their attitude towards AIDS patients. In addition, the programme is highly praised by the students.

Abortion, Induced↗
PubMed2001

[Effects of heat stress on DA mediated PI signal transduction system in rat striatum].

Objective. To study the effects of heat stress on dopamine (DA) and related phosphatidylinositol (PI) signal transduction system members: PLA2, PI, Ca2+ in rat striatum. Method. Male Wistar rats were randomly divided into control group and heat stressed group. Heat stressed rats were placed in small hot chambers and taken out as soon as their rectal temperatures (Tr) reached the preset temperature. Then the animals were killed and their striatums were taken out. Fluorospectrophotometry, HPLC, Fura-2/AM fluoresence labelled method and acidalkaline titration were used to measure the content of DA, PI, [Ca2+]i and the enzyme activity of PLA2. Result. During heat stress, when rats' Tr reached 41.0 degrees C or higher, with increase of Tr, DA content increased continuously. When Tr = 43.0 degrees C, DA content was significantly higher than control. When Tr = 41.0 degrees C PLA2 activity was higher than control significantly, PI content of heat stressed group decreased significantly than control. [Ca2+]i increased significantly when Tr = 42.0 degrees C as compared with control. But if DA receptor2 (D2R) antagonist was given an hour before heat stress, [Ca2+]i decreased and Tr took a longer time to get to 42.0 degrees C. Conclusion. During heat stress, DA mediated PI signal transduction system was activated. The increase of [Ca 2+]i might be mediated by D2R, and D2R antagonist may improve thermotolerance.

Animals↗
PubMed2001

[Protective effect of Panax quinquefolium 20s-proto-panaxdiolsaponins on acute myocardial infarction in dogs].

OBJECTIVE: To study the protective effects of Panax quinquefolium 20s-protopanaxdiolsaponins extracted from leaves of P. quinquefolium (PQDS) on acute myocardial infarction(AMI) in dogs. METHOD: The parameters of myocardial infart size, the serum CK and LDH activity, myocardial metabolism, free radicals and coronary circulation etc were determined by using the model of ligation of LAD in the anaesthetized open-chest dogs. RESULT: In dogs treated with PQDS(in a dosage of 10 and 20 mg.kg-1 i.v. infusion), the myocardial infarct size, the activity of serum CK, LDH and the contents of serum FFA and LPO were decreased, whereas the activity of serum SOD and GSH-Px increased markedly. At the same time, myocardial blood flow was increased and coronary vascular resistance decreased significantly. CONCLUSION: PQDS has protective effect on myocardial ischemia by modifying metabolic dysfunction of FFA, inhibiting oxygen free radical mediated peroxidation of membrane lipids, enhancing endogenous antioxidase activity and increasing myocardial blood supply.

Animals↗
PubMed2001

[Characteristics of alpha2-adrenoceptor mediated contractile response in isolated aortae of rats].

In order to investigate the characteristics of vascular alpha(2)-adrenoceptor (alpha(2)-AR) and its relation to alpha(1)-AR, isolated Wistar rat (10 weeks) aortae were used as a model for testing contractile function in vivo. It was found that both alpha(1) and alpha(2)-AR (mainly alpha(1)-AR) mediated the contractile response. While alpha(1)-AR enhanced the contractile response mediated by alpha(2)-AR, alpha(2)-AR had no effect on that mediated by alpha(1)-AR. When alpha(1)-AR was irreversibly blocked and the activity of alpha(2)-AR remained intact, the contractile response mediated by alpha(2)-AR was no longer observed. The contractile response only reappeared in the presence of KCl of the threshold level, and the extent of the maximum contraction decreased, compared with control (with alpha(1)-AR being intact). The results show that there exists a functional alpha(2)-AR in rat aorta, however, the contractile effect of which depends on the stimulation of alpha(1)-AR.

Adrenergic alpha-Antagonists↗
PubMed2000

[Antagonistic characterization of 1-(2,6-dimethylphenoxyl)-2-(3,4-dimethylphenyl ethylamino) propane hydrochloride on alpha 1-adrenoceptor].

AIM: To study the antagonistic effect of 1-(2,6-dimethylphenox)-2-(3,4-dimethylphenyl ethylamino) propane hydrochloride (DDPH) on alpha 1-adrenoceptor (AR). METHODS: Radioligand binding assay was used. Specific 125I-BE2254 (2-beta(4-hydroxyphenyl)-ethyl aminomethyl-tetralone) binding was measured by incubating membrane of rat cerebral cortex, spleen and the three cloned alpha 1-AR subtypes (alpha 1A, alpha 1B, alpha 1D) stably expressed in human embryonic kidney 293 cell preparation with a single concentration of 125I-BE2254 in the presence of 14 concentrations of DDPH. Equilibrium binding constant (KI) and Hill coefficients (nH) were determined from Hill plots. The -log value of the KI was expressed as pKI. Contractile responses of isolated rat aorta, renal artery ring and spleen were determined. The pA2 values for DDPH in competitively inhibiting NE-stimulated contraction of tissues were measured with the method of Ainlakshana and Schild. RESULTS: DDPH competitively inhibited binding of 125I-BE2254 to alpha 1-AR in a concentration-dependent manner. The pKI values for DDPH in rat cerebral cortex and spleen were 7.17 +/- 0.06 and 7.41 +/- 0.11, respectively, and the Hill efficiency values were not significantly different from unit. The pKI values for cloned alpha 1A, alpha 1B and alpha 1D-AR were 7.21 +/- 0.12, 6.88 +/- 0.04 and 7.26 +/- 0.06, respectively, and the Hill efficiency values were not significantly different from unit. Contractile studies showed that DDPH competitively antagonized the NE concentration-response curve with a pA2 values of 7.40 +/- 0.23 in aorta, 7.41 +/- 0.04 in renal artery and 7.63 +/- 0.07 in spleen and the slopes of schild plot were not significantly different from unit. The pKI values for DDPH in tissues and the cloned alpha 1A or alpha 1D-AR were shown to fit well in with the pA2 values in antagonizing NE-induced constriction in rat isolated aorta, renal artery and spleen. CONCLUSION: These results suggest that DDPH appear to be a non-subtype selective competitive antagonist for alpha 1-AR.

Adrenergic alpha-Antagonists↗
PubMed1997

[Sertindole, a novel alpha 1A-adrenoceptor selective antagonist].

The antagonism effect of sertindole on alpha 1-AR subtypes was studied by combining radiologand binding assays in three cloned alpha 1-AR subtypes stably expressed in human embryonic kidney 293 cells and contractile response experiment in isolated rat blood vessels. The results showed that the affinity for sertindole in the cloned alpha 1A-AR (pKI 8.90 +/- 0.17) was 69-fold (pKI 7.06 +/- 0.09) and 132-fold (pKI 6.78 +/- 0.07) higher than that for the cloned alpha 1B- and alpha 1D-AR, respectively. The pA2 values for sertindole in antagonizing NE-induced vasoconstriction in isolated rat aorta and renal artery were shown to fit well to the pKI values on cloned alpha 1D- and alpha 1A-AR, respectively. Pretreatment of membrane preparations with sertindole for 30 min significantly reduced the maximal binding capacities. (Bmax) of 125 IBE2254 to the three cloned alpha 1-AR subtypes without alteration of affinities (KD values). In the presence of sertindole, the Bmax of 125IBE2254 binding to the cloned alpha 1-ARs were not significantly changed, while the KD values were significantly increased. Thus, sertindole is a selective irreversible competitive alpha 1-AR antagonist with alpha 1A subtype.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1997

Induction of ICE and inhibition of c-fos, jun D and zif 268 in 12-month old spontaneously hypertensive rats.

A semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay was used to examine ICE, c-fos, jun D and zif 268 mRNA expression in the aortic and renal artery of 12-month old SHRs and wistar rats. Using this assay system, it was observed that the levels of aortic and renal artery expression of ICE were markedly higher in SHRs than in wistar rats. In contrast, the aortic and renal artery expression of immediate early genes (IEGs), c-fos, jun D and zif 268, were significant lower in SHRs than in wistar rats. Thus, our results suggest that differential regulation of death gene ICE and IEGs such as c-fos, jun D and zif 268 might be involved in the mechanism of pathogenesis of hypertension.

Amino Acid Isomerases↗
PubMed1997

[Comparison of functional alpha 1-adrenoceptor subtypes in aortae between 12 month- and 10 week-old rats].

The distribution of alpha 1-adrenoceptor and its subtypes in isolated aortae was compared between 12 month- and 10 week-old Wistar rats by determinating vasoconstrictor responses. In the 12 month-old rats, compared with the 10 week-old rats, (1) the maximal contraction induced by norepinephrine (NE) was reduced, without significant alteration of pD2 value; (2) the inhibitory effect of chlorethylclonidine (an irreversible antagonist for alpha 1B and alpha 1D subtype) on NE-induced contraction was weaker; (3) using NE as an agonist, the pA2 value for WB4101 (an alpha 1A- and alpha 1D-selective antagonist) was not changed, but the pA2 value for BMY7378 (an alpha 1D-selective antagonist) was decreased, while the pA2 value for sertindole (an alpha 1A-selective antagonist) was increased. Thus, differently from the 10 week-old rats in which only alpha 1D-adrenoceptors mediate NE-induced contraction in aortae, both alpha 1A- and alpha 1D-adrenoceptors (mainly alpha 1A) mediate the response in the 12 month-old rats.

Adrenergic alpha-Agonists↗
PubMed1996

[Antagonistic effect of tetrahydroproberberine homologues on alpha 1-adrenoceptor].

The antagonistic effect of tetrahydroproberberine (THP) homologues on alpha 1-adrenoceptor was studied by combination of radioligand binding assays and measurements of vasoconstriction responses. The results showed that l-tetrahydropalmatine (l-THP), l-stepholidine (l-SPD), THPB-18 and tetrahydroberberine (THB) competitively inhibited the 125I-BE2254 specific binding in rat cerebral cortex with pK1 values of 5.54 +/- 0.36, 5.56 +/- 0.47, 5.75 +/- 0.56 and 6.01 +/- 0.60, respectively, and the Hill efficiency was not significantly different from unity. They inhibited phenylephrine-induced constrictions with pA2 values of 5.48 +/- 0.58, 5.66 +/- 0.54, 5.64 +/- 0.34 and 5.45 +/- 0.76, respectively, and the slopes of Schild plot were not significantly different from unity. The results indicate that the 4 THP homologues are non-subtype selective competitive antagonists for alpha 1-adrenoceptor with similar affinities.

Adrenergic alpha-Antagonists↗
PubMed1995

[Effects of long-term atenolol treatment on beta-adrenoceptor subtypes in rat heart].

The effects of long-term beta 1-AR selective antagonist atenolol treatment on beta-adrenoceptor subtypes were studied by radioligand binding assay, function determination and cAMP accumulation measerment in rat heart. The reasults showed that during long-term administration of atenolol: (1) The density of total beta-AR was increased by approximately 57%; the positive inotropic response and cAMP formation induced by activation of beta-AR were also enhanced. (2) The 125I-pindol competitive inhibition curve for CGP20712A showed that there were no significant difference in the percentage of beta 1- and beta 2-AR sites between the atenolol treated rats and the control rats; pA2 values for selective beta 1-AR antagonist CGP20712A and pKB values for selective beta 1-AR antagonist ICI 118, 551 were not significantly different in the two groups. The results suggested that beta 1- and beta 2-adrenoceptors were upregulated not only in density but also in positive inotropic effect to the same extent.

Animals↗
PubMed1994

[Effects of the leaves of Acanthopanax senticosus (Rupr. et Maxim.) Harms. on myocardial infarct size in acute ischemic dogs].

Effects of saponin isolated from the leaves of Acanthopanax senticosus (ASS) on myocardial infarct size were studied in acute ischemic dogs. The results showed that ASS (in a dosage of 25.50 mg/kg, iv) could significantly reduce the sizes of acute myocardial infarcts and decline the serum CK and LDH activity at 6h after ligation of LAD. It could also decrease the serum FFA levels at 3h and 6h after LAD occlusion.

Animals↗
PubMed1992

The pregnane glycoside marsdekoiside A from Marsdenia koi.

A new pregnane glycoside, marsdekoiside A was isolated from the stems of Marsdenia koi (Asclepiadaceae) and its structure was elucidated from chemical and spectral data as 12-cinnamoyl-dihydrosarcostin-3-O-methyl-6-deoxy-beta-D-allopyr ano syl-(1----4)-O-beta-D-oleandropyranosyl-(1----4)-O-beta-D-++ +cymar opyranoside.

Carbohydrate Sequence↗
PubMed1992

[Catch up and follow up of natal teeth: report of 6 cases]

6 cases with natal teeth were found in 11930 live births.5 cases, in which eight natal teeth had been found, also had been followed-up for 38-54 months after birth and five crownless root-like mass were found in 4 cases out of 5 at the site where natal teeth had been extracted at the time of birth. The histological study was made in one natal teeth and one root-like mass.

Journal Article↗
PubMed1991

Studies on the antifertility components from Marsdenia koi.

By random screening test, Marsdenia koi was found to have antifertility activity on SD rat. From MeOH extracts of this plant two steroidal glycosides, marsdekoiside A and B, were isolated, and their structures were elucidated on the basis of spectral evidence and by comparison of the hydrolysis products with the authentic samples. Both are newly identified compounds, and marsdekoiside A has good antifertility activity.

Animals↗