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Biomedical subjects

C S Tang

Publications and source records attributed to C S Tang.

At least 145 records · Page 8Linked to original sources
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↗
PubMed1989

[Distribution of substance K in the rat heart and its cardiovascular effects].

The present work was to investigate the distribution of Substance K (SK) in the rat heart and its cardiovascular effects. The content of SK-like immunoreactive material (SKLI), determined by using specific radioimmunoassay, was higher in the atrium (19.9 +/- 3.5 pmol/g tissue) than in the ventricle (4.1 +/- 0.8 pmol/g tissue). SKLI in the heart existed in the nerves fibers and its molecular form was identical with synthetic SK. There were high affinity binding sites of SK on the cardiohybricyte CP 8401: KD = 0.161 nmol/L, Bmax = 8.08 pmol/L. SK stimulated the release of ANF from the cardiohybricytes and from the isolated rat atria. Furthermore, SK injected intravenously induced a hypotensive effect in rats, and decreased left ventricle end systolic pressure (LVESP), +/- LVdp/dtmax, as well as slightly increased heart rate (HR). In isolated Langendorff perfusion heart of rat, SK increased HR, LVdp/dtmax, left ventricle peak systolic pressure (LVPSP) and perfusion pressure (PP). These effects of SK were inhibited by a tachykinin receptor antagonist, (D-Pro2, D-Trp7.9)-SP. These findings suggest that SK exist in the heart and might be able to bind with its specific binding sites on the cardiocytes, thus inducing the release of ANF from the atrium and regulating cardiovascular functions.

Animals↗
PubMed1989

[Factors affect Na(+)-Ca2+ exchange in rat's cardiomyocytes and protein-reconstituted liposomes].

Rat's Ca-resistant ventricular myocytes and reconstituted liposomes of canine cardiac sarcolemma were used in analysing factors affecting Na(+)-Ca2+ exchange system. Decrease in extracellular (extravesicular) Na+ or increase in intracellular Na+ by inhibition of the Za(+)-K(+)-ATPase with ouabain stimulated the Na(+)-Ca2+ exchange. Mn2+, an antagonist of Na(+)-Ca2+ exchange, dose-dependently inhibited the Na(+)-dependent Ca2+ uptake. However, verapamil had no effect on it. Arachidonic acid and lipid peroxides caused by incubation with-H2O2 significantly stimulated Na(+)-Ca2+ exchange in a dose-dependent fashion.

Animals↗
PubMed1989

[Changes in metallothionein content of the heart and liver during acute myocardial infarction in rats].

Metallothionein (MT) is an important endogenous anti-injury substance involved in the defensive system. In myocardial infarction model produced by left coronary artery occlusion in-rat, the content of left ventricular myocardial MT was significantly increased to a maximum on 4th day by 6-fold compared with preoperative value, and the content of hepatic MT increased by 3.5-fold on the 2nd day. During the whole experimental period (seven days) the MT content in heart and liver was significantly higher than those in the pre-operation period (P less than 0.01). Pretreatment with reserpine did not alter the dynamic changes of cardiac and liver MT content during myocardial infarction. The above results suggest that this increase in tissue MT is not influenced by catecholamine.

Animals↗
PubMed1989

[Significance of endothelin in shock pathogenesis].

Endothelin is a recently discovered bioactive peptide produced by vascular endothelial cells. By means of specific radioimmunoassay we found that plasma endothelin level in patients with late septic shock was significantly increased. And a typical shock model in healthy rats was reproduced by continuous infusion of endothelin (endothelin shock). Infusion of endothelin at a small dose to hemorrhagic shocked rats deteriorated the shock process and resulted in an irreversible development. From these results it is suggested that endothelin may be an endogenous injury-inducing factor, acting as one of the important humoral factors involved in shock pathogenesis.

Animals↗
PubMed1989

[Anoxia-reoxygenation injury in isolated rat myocytes is modulated by cell sodium during the anoxia period].

Using the model of anoxia-reoxygenation injury in isolated rat myocytes, we observed that incubation of myocytes with ouabain, inhibitor of Na+-K+ ATPase, during anoxia period significantly increased the cell sodium content. These myocytes demonstrated severe injury and intracellular calcium overload during reoxygenation period. The sodium content of myocytes at the end of anoxia period was positively correlated with the overload of intracellular calcium at reoxygenation (r = 0.882, P less than 0.01). Mn2+, an inhibitor of Na+-Ca2+ exchange, significantly attenuated the anoxia-reoxygenation injury when given during reoxygenation period. Mn2+ also inhibited the cell injury caused by incubation of myocytes with Na+-free medium. These results suggest that anoxia-reoxygenation injury of rat myocytes is modulated by cell sodium during the anoxia period, and the Na+-Ca2+ exchange mechanism plays an important role in influx of extracellular calcium during reoxygenation period.

Animals↗
PubMed1989

Coupling of volume and Na+ transport in frog skin epithelium.

Whole skins and isolated epithelia were bathed with isotonic media (congruent to 244 mOsm) containing sucrose or glucose. The serosal osmolality was intermittently reduced (congruent to 137 mOsm) by removing the nonelectrolyte. Transepithelial and intracellular electrophysiological parameters were monitored while serosal osmolality was changed. Serosal hypotonicity increased the short-circuit current (ISC) and the basolateral conductance, hyperpolarized the apical membrane (psi mc), and increased the intracellular Na+ concentration. The increases in apical conductance and apical Na+ permeability (measured from Goldman fits of the relationship between amiloride-sensitive current and psi mc) were not statistically significant. To verify that the osmotically induced changes in ISC were mediated primarily at the basolateral membrane, the basolateral membrane potential of the experimental area was clamped close to 0 mV by replacing the serosal Na+ with K+ in Cl--free media. The adjoining control area was exposed to serosal Na+. Serosal hypotonicity produced a sustained stimulation of ISC across the control, but not across the adjoining depolarized tissue area. The current results support the concept that hypotonic cell swelling increases Na+ transport across frog skin epithelium by increasing the basolateral K+ permeability, hyperpolarizing the apical membrane, and increasing the electrical driving force for apical Na+ entry.

Amiloride↗
PubMed1988

Placebo effects in the treatment of male dating anxiety.

The outcomes of cognitive-behavioral and high credibility placebo group treatments were compared in a sample of nineteen heterosocially anxious males. At post-test and at a 3-month follow-up, both treatments showed improvement on self-report measures of interpersonal functioning (ps less than 0.05). The cognitive-behavioral treatment showed a consistent pattern of improvement on self-report and behavioral measures of anxiety (ps less than 0.05), but, overall, the groups showed comparable levels of effectiveness. The possibility that both treatments relied on placebo mechanisms is discussed.

Adult↗