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Biomedical subjects

C S Tang

Publications and source records attributed to C S Tang.

At least 19 recordsLinked to original sources
PubMed1992

Sexual and aggressive motives in sexually aggressive college males.

The relative contributions to sexual aggression of general sexual and aggressive motives and their respective inhibitory factors were compared. One hundred forty-three university males responded to self-report measures of sexual and aggressive drives, sex and hostility guilt, social desirability response bias, and history of coercive sexuality. With the effects of social desirability controlled, the only predictor of sexual aggression was Sex Guilt, which predicted level of force used but not intimacy of the sexual act obtained.

Adolescent↗
PubMed1992

Effect of bicarbonate on intracellular potential of rabbit ciliary epithelium.

Extracellular HCO3- hyperpolarizes the intracellular potential and makes the aqueous medium negative with respect to the stromal surface of the rabbit ciliary epithelial syncytium. The bases for these observations have been unclear. We have been studying the bicarbonate-induced hyperpolarization (BIH) with sustained intracellular recordings for periods as long as 1-2 hrs. The BIH was observed [6.0 +/- 0.4 mV (mean +/- SE, N = 22)] even when the external pH was clamped constant by appropriately changing the CO2 tension. External HCO3- was required since aeration with CO2 at low external pH did not replicate the BIH. DIDS [4,4'-diisothiocyano-2,2'-disulfonic acid] did not abolish the effect. The hyperpolarization is unlikely to reflect the pH dependence of K+ channels alone, since the effect was not reduced by either 2 mM Ba2+ alone or 2 mM Ba2+ together with 50-100 microM quinidine. The BIH depends directly or indirectly on external Na+, since the sign of the polarization response was reversed either by replacing Na+ with N-methyl-D-glucamine or by blocking the Na+,K(+)-exchange pump with 50-100 microM ouabain. Replacement of external Cl- with NO3- or application of the Cl(-)channel blocker NPPB [5-nitro-2-(3-phenylpropylamino)-benzoate] depolarized the membrane and reversed the sign of the BIH. The response of the ciliary epithelium to HCO3- is complex and may arise from several mechanisms. We suggest that one important element is an anion channel whose conductance is reduced by bicarbonate and whose reversal potential is indirectly dependent on the operations of the Na+,K(+)-pump and a Cl(-)-linked symport.

Animals↗
PubMed1992

[Effect of endothelin on isolated myocytes from rat heart].

The mechanism of endothelin (ET) action on isolated myocytes of rat heart was investigated. Administration of 10(-9)-10(-7) mol/L ET caused dose-dependently severe contracture of myocytes, increase in cytosolic lactate dehydrogenase leakage and increase of cellular total calcium. ET also enhanced 45Ca2+ influx in myocytes, that could be antagonized by calcium channel blocker verapamil. Incubation of Fura-2 -preloaded myocytes with ET would induce a significant increase of cytosolic free Ca2+, and this effect of ET could also be partly antagonized by verapamil. These results suggest that ET enhances Ca2+ influx in myocytes mainly through voltage-dependent calcium channel, by which ET exerts its biological action.

Animals↗
PubMed1992

[Effect of NO-like relaxing factor (NO-LRF) in rat tourniquet shock].

On tourniquet shock (ToS) rat model, it was found that the reactivity of isolated perfused aortic ring to noradrenaline was decreased, while the cGMP content of the aortic tissue was increased. These ToS-induced changes could be potentiated or attenuated respectively by perfusion with NO-precursor, L-arginine, or NO-synthesis inhibitor L-NNA independent of the presence of vascular endothelium. Guanylate cyclase inhibitor, methylene blue, could also attenuate the aortic reactivity. All these results suggest that the aortic musculature can produce a NO-LRF factor capable of lowering the vascular reactivity of the ToS animals. That L-arginine can ameliorate while L-NNA can exacerbate ToS, suggest that NO-LRF do play an adaptive role in the protective mechanism of the organism during ToS.

Animals↗
PubMed1992

[Role of endothelin in the pathogenesis of rat experimental hypertension produced by aorta narrowing and saline uptake].

Endothelin is a bioactive polypeptide released from vascular endothelium, which has a strong action promoting vascular contraction, proliferation and hypertrophy of vascular smooth muscle cells. The present investigation was performed on the hypertensive rat produced by narrowing abdominal aorta and drinking saline. It was observed that the level of plasma endothelin in the hypertensive rats was doubled (9.70 +/- 0.68 vs. sham group 4.11 +/- 0.33 pg/ml, P < 0.01), and administration of specific endothelin-antiserum into hypertensive rats significantly attenuated the increase in the blood pressure (18.97 + 1.32 vs. 27.33 + 0.09 kPa in untreated hypertensive rats, P < 0.01), and dramatically ameliorated malfunction resulting from myocardial hypertrophy. The results suggest that endothelin is an important factor in the pathogenesis of hypertension, and that inhibition of endothelin action may be a new effective way in prevention and therapy of hypertension.

Animals↗
PubMed1992

[The effect of nitrous oxide anesthesia combined with low dose alfentanil for minor surgery of short duration].

This study was conducted in 30 adult patients with ASA class I-II physical status who received minor operations. Anesthetic induction was achieved by injecting thiopental 4 mg/kg intravenously in addition to N2O/O2 (4L/2L) delivered via Ventri Mask, followed by alfentanil 7 micrograms/kg intravenously 3 min later. Maintenance of anesthesia was accomplished by N2O/O2 in conjunction with alfentanil 0.25-2.5 micrograms/kg/min, delivered intravenously by a syringe pump. Our result showed that in an operation of average duration around 40.2 +/- 10.5 min., the average dose of alfentanil used was 0.62 +/- 0.15 micrograms/kg/min. The respiration rate fell from 13.4 +/- 0.4 cpm to 8.4 +/- 1.1 cpm 2 min later following alfentanil injection, which was statistically significant. SaO2 fell from 97.9 +/- 0.4% to 94.0 +/- 0.8% 3 min after alfentanil injection, which was statistically significant. End-tidal carbon dioxide partial pressure elevated from 39.4 +/- 0.6 mmHg to a peak of 45.3 +/- 1.2 mmHg 5 min after alfentanil injection which was also statistically significant. Temporary apnea was noted in 3 cases, but they all resumed spontaneous respiration after a short period of assisted ventilation. Changes in systolic and diastolic pressure during anesthesia were not marked. Pulse rate was noted to decrease from 80.3 +/- 2.7 bpm to 70.5 +/- 2.0 bpm 1 min after alfentanil injection, which was statistically significant (p less than 0.05). After discontinuation of N2O, the time required to regain the ability to follow orders of "open your eyes," "show your thumb" and "say your name" in sequence was 72.5 +/- 10.6s, 88.2 +/- 11.6s, 128.1 +/- 23.0s, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Effect of ANP on angiotensin II--stimulated multiplication and c-fos oncogene expression of SHR vascular smooth muscle cells].

By means of technique of cell culture, 3H-thymidine incorporation and dot blot, it was demonstrated that angiotensin II (AGT II) stimulated proliferation and c-fos oncogene expression in cultured SHR vascular smooth muscle cells (VSMC) in a dose-dependent manner. This effect of AGT II was significantly inhibited by co-incubation with ANP. The results suggest that proliferation of VSMC is regulated by some interaction between AGT II and ANP.

Angiotensin II↗
PubMed1991

[A histopathological study of bone marrow in acute myeloid leukemia. Bone marrow biopsy changes before chemotherapy and comparison with bone marrow smears].

Histopathological changes of pretreatment bone marrow biopsy from 42 cases with acute myeloid leukemia (AML) were described. A considerable difference was shown between the results of aspirate smears and the findings of plastic embedded biopsy sections, particularly in bone marrow cellularity such as infiltration of inflammatory cells and presence of residual hemopoietic cells, qualitative and quantitative abnormalities of megakaryocytes suggestive of myelodysplastic features were more accurately assessed in the sections of marrow biopsy than in the aspirate smears. In three cases there was considerable infiltration of maturing but dysplastic granulocytic cells and erythroid precursors in the sections, but not in the aspirate smears. Our study shows that plastic embedded biopsy sections provide more information than aspiration smears for the diagnosis of AML.

Adolescent↗
PubMed1991

[Effect of endothelin on rat mesenteric microvessels].

By video microscope, it was observed that endothelin (ET) caused constriction of the mesenteric microvessels of pentobarbital-anesthetized Wistar rats in a dose-dependent manner. With the consequence of causing a decrease of rate of blood flow and even some microcirculation disorder, the action was long lasting. The constrictive effect of ET on microvessel was much stronger than norepinephrine. The results suggest that ET is a potent vasoconstrictor for microvessel and may play an important role in causing microcirculatory disorder.

Animals↗
PubMed1991

Role of Na(+)-Ca2+ exchange system in the pathogenesis of myocardial ischemia-reperfusion damage.

Results from a systematic experiment on isolated perfused rat heart and isolated myocytes of adult rat showed that the mechanism of calcium influx during myocardial ischemia-reperfusion is due to the development of intracellular sodium overload during ischemic period; on reperfusion, the high intracellular Na+ content activated the reverse direction of Na(+)-Ca2+ exchange over myocardial sarcolemma (SL), thus a large quantity of extracellular Ca2+ fluxed over the SL to the intracellular space, forming a condition of intracellular Ca2+ overload, which leads to irreversible damage of the myocardium.

Animals↗
PubMed1990

Depression and judgment of control: impact of a contingency on accuracy.

In this study we sought to determine whether mild depressives and nondepressives could respond adaptively and self-correct their judgments of contingency when it was clearly advantageous to do so. Ninety-six undergraduates were given four contingency-learning tasks involving pressing or not pressing a key to turn on a light and to judge the degree of control their responses had over light onset. On the first task, which included a monetary contingency only on light onset, mild depressives were relatively accurate in their judgments of control. Tasks 2 through 4, which also included a monetary contingency and feedback on accuracy of judgment of control, showed a Mood x Task interaction. Mild depressives, but not nondepressives, became more accurate, and by the last task, mild depressives were more accurate than nondepressives. Results were discussed in terms of incentive, feedback, and task exposure.

Adolescent↗
PubMed1990

[Effect of endothelin on the release of angiotensin II from rat cardiovascular system].

The existence of angiotensin II immunoreactive substance in rat cardiovascular system was demonstrated by RIA and immunohistochemistry techniques. In atrium, aorta and cultured rat aorta smooth muscle cells, angiotensin II content is 7.2 + 2.7 pg/mg protein, 152.4 + 59.2 pg/mg protein and 3.5 + 0.8 pg/2 x 10(5) cells respectively. Endothelin, a potent vasoconstricting polypeptide, can enhance the release of angiotensin II from cultured rat aorta and aortic smooth muscle cells significantly. The results suggest that endothelin may be involved in the regulation of local blood flow and vascular tone, and it may also implicate the pathogenesis of some cardiovascular diseases such as cardiohypertrophy and vascular hypertrophy.

Angiotensin II↗
PubMed1990

[Antagonism of verapamil on the injurious action of endothelin of isolated rat heart].

Isolated rat hearts perfused with endothelin at a concentration of 10(-8) mol/L showed serious functional and cellular myocardial deterioration as manifested by a significant increase of mean perfusion and left ventricular pressure, decrease of +/- LV dp/dtmax, leakage of myocardial protein, formation of lipid peroxides, increase of myocardial calcium content, etc. Calcium channel blocker, verapamil, effectively antagonized the injurious action of endothelin on rat heart whether administered along with or after endothelin perfusion.

Animals↗
PubMed1990

[Clinical study of awake fiberoptic nasotracheal intubation for difficult opening mouth patients].

The intubation technique for those surgical patients considered to be difficult intubation were classically managed by blind nasotracheal intubation, tracheostomy and so forth. These procedures are rather invasive and resulted in post-operative complications. 30 adult patients of ASA class II-III with difficulty in intubation were chosen to receive awake fiberoptic nasotracheal intubation. Our aim of study is to evaluate the change of blood pressure, heart rate and SaO2 of these patients at 4 stages: I) preanesthesia II) transtracheal local block III) during intubation IV) post-intubation. As a result, there were no significant difference in comparing the parameters among these 4 stages. Additionally, fiberoptic guiding provide a direct vision on the way of intubation, enhance the successful rate of difficult intubation and minimize further trauma and discomfort to the patients. Therefore fiberoptic intubation may suitable in patients with difficult intubation.

Adult↗