Search PubMed⌕ Search

Biomedical subjects

C S Tang

Publications and source records attributed to C S Tang.

At least 109 records · Page 6Linked to original sources
PubMed1995

[Impaired calcium uptake by cardiac sarcoplasmic reticulum and its underlying mechanism during rat septic shock].

The underlying mechanism of Ca2+ uptake function of cardiac sarcoplasmic reticulum (SR) was investigated in the rat septic shock model produced by cecal ligation and puncture (CLP). The results are as follows. During the early phase of sepsis, the initial rate of ATP-dependent Ca2+ uptake by SR was decreased, while both the capacity of Ca2+ uptake and the activity of Ca(2+)-ATPase were unaffected. In the late sepsis, the impairment in SR function was even greater as the initial rate and the capacity of Ca2+ uptake by SR were significantly decreased, and this was paralleled by a reduction in Ca(2+)-ATPase activity. Although Ca2+ affinity (Km value) to calcium pump and the A0.5 values for Mg2+ and ATP activation on the Ca2+ uptake rate were unchanged, during sepsis the phosphorylation of SR vesicles by adding of catalytic subunit of the cAMP-dependent protein kinase (PKA), calmodulin, or the fragment of PKC into Ca2+ uptake buffer, failed to stimulate Ca2+ uptake activities of SR isolated from early or late septic rats. These data suggest that depression of cardiac SR function is aggravated as sepsis develops, the impairment of SR Ca2+ uptake is possibly based on a mechanism of defective phosphorylation of SR rather than the ionic and energic regulatory actions of Ca2+, Mg2+, ATP on cardiac SR.

Animals↗
PubMed1995

[Altered ryanodine receptor of rat cardiac sarcoplasmic reticulum and its underlying mechanism during septic shock].

The present study was undertaken to observe the changes of Ryanodine receptor of cardiac junctional sarcoplasmic reticulum (SR) in relation to membrane lipid microenvironment alteration during septic shock. The results showed that the Bmax for 3H-ryanodine binding to cardiac junctional SR was decreased by 41.3% (3.9 +/- 0.1 vs. sham 6.6 +/- 0.7 pmol/mg, P < 0.01) while the Kd value was unaffected during late septic shock (CLP 18 h). Ca2+ activated 3H-ryanodine binding significantly and reached a saturation value when Ca2+ concentration was 5 x 10(-5) mol/L, while the S0.5 and the Hill coefficient values remained unchanged during septic shock. Caffeine, ATP, and AMP-PCP activated while Mg2+, ruthenium red inhibited 3H-ryanodine binding in both groups but the A0.5 (concentration requires for half maximum activation) and the IC50 (concentration requires for half-maximum inhibition) for the above mentioned activators and inhibitors, were respectively unaffected during septic shock. Digestion of cardiac SR isolated from control rats with phospholipase A2 inhibited 3H-ryanodine binding, which could be dramatically recovered by the incorporation of phosphatidylcholine (PC), or phosphatidylserine (PS), or phosphatidylethanolamine (PE) into the isolated cardiac SR. Incorporation of above phospolipids into SR isolated from septic rats reversed shock-induced inhibition of 3H-ryanodine binding. It is concluded that the mechanism responsible for the inhibition of 3H-ryanodine binding of junctional SR during septic shock may be related to modification of membrane lipid microenvironment in response to PLA2 overactivation during septic shock.

Animals↗
PubMed1995

[Alteration of phospholamban phosphatase activity associated with cardiac sarcoplasmic reticulum during sepsis in rats].

In the present study, rat cardiac sarcoplasmic reticulum (SR) phospholamban (PLB) phosphatase was partially purified by chromatography on DEAE-Sephacel. This PLB phosphatase was indentical to phosphatase-1. It was shown on electrophoresis of SDS-PAGE autoradiography that the PLB phosphatase in rats during early sepsis (ES) depressed dephosphorylation of substrates (32P-phosphorylase a and 32P-SR). However, dephosphorylation of the substrates by the partially purified phosphatase during late sepsis (LS) was same as that in control rats. The partially purified PLB phosphatase activity in ES rats was significantly decreased, but showed no change in LS rats. The results above were confirmed by a studing of the substrate concentration (enzyme concentration, time)--enzyme reaction velocity curve in showing that both affinity and maximum initial velocity (Vmax) of the phosphatase in the ES rats were decreased, but had no change in those in the LS rats.

Adenosine Triphosphatases↗
PubMed1995

[A study on the mechanism of the cardiac adenylyl cyclase activity alteration in septic rats].

The present work showed that cardiac sarcolemmal (SL) adenylyl cyclase (AC) and purified AC maximal activity of septic rat (cecal ligaation and puncture, CLP) were significantly increased during the early sepsis (ES, CLP 9 h) but decreased in the late sepsis (LS, CLP 18 h). Similar alterations were observed in cardiac sarcolemmal protein kinase C (PKC) activity. Sensitization and desensitization of rat SL adenylyl cyclase during ES and LS were respectively correlated with activition and inhibition of PKC. The biphasic changes of AC and PKC were independent of beta- and alpha 1-adrenergic receptor systems. The rat cardiac sarcolemmal PKC activation and AC sensitization during ES is related to M-cholinergic receptor system. The system, however, is not involved during the LS PKC inhibition and AC desensitization.

Adenylyl Cyclases↗
PubMed1995

Coping and psychological distress of Chinese parents of children with Down syndrome.

Coping and correlates of psychological distress of Chinese parents of children with Down syndrome were examined and compared to parents of children with language delays or no disabilities. Individual parent scores were used for analyses, with groups and gender of child and parent as independent factors. Down syndrome group parents reported the most frequent use of avoidance coping style, followed by parents of the language delay and no disabilities groups. Compared to parents in the no disabilities group, the other parents reported a higher level of psychological distress, were less optimistic, felt less self-efficacious, and engaged in more frequent use of self-reliance coping style. Main effects for parent gender revealed that mothers engaged in more frequent use of self-reliance, avoidance, and seeking social support coping styles. Mothers also reported a higher level of distress but lower levels of optimism and self-mastery. Intercorrelations among variables showed that avoidance coping style and self-mastery emerged as the two robust correlates of parental distress.

Adaptation, Psychological↗
PubMed1994

ntf1+ encodes a 6-cysteine zinc finger-containing transcription factor that regulates the nmt1 promoter in fission yeast.

The nmt1+ gene of the fission yeast Schizosaccharomyces pombe is subject to transcriptional repression mediated by thiamine. The promoter of nmt1+ has been used to construct a series of vectors that are now commonly used for the regulated expression of genes in S. pombe. In this report, we described ntf1+, a gene involved in regulating nmt1+ expression. The ntf1+ gene was cloned in a high copy suppressor screen that utilized a construct, nmt1:wee1+, in which expression of the mitotic inhibitor Wee1 tyrosine kinase was placed under the control of the nmt1 promoter. ntf1+ encodes a 706-amino acid protein that shares substantial homology with a family of Cys6 zinc finger-containing transcription factors typified by GAL4 from Saccharomyces cerevisiae. Increased gene dosage of ntf1+ greatly increases both the repressed and derepressed activity of the nmt1 promoter. Cells having a disrupted version of ntf1+ are viable thiamine prototrophs, but basal expression from the nmt1 promoter is greatly reduced. These data demonstrate that Ntf1 plays an important role in regulating nmt1 expression.

Amino Acid Sequence↗
PubMed1994

Dithiothreitol homogenization of prefixed sputum for lung cancer detection.

The technique of chemical homogenization of sputum for cancer detection was revisited. The mucolytic agent dithiothreitol (DTT) had been used by the authors on fresh specimens. In this study, its effectiveness in homogenizing prefixed sputum was investigated. Fifty-seven positive samples were examined: 28 were prefixed with 2% carbowax in 60% ethanol and 29 in 3% carbowax in 60% ethanol. Each specimen was divided equally into three parts and homogenized immediately, 3 and 7 days later, respectively, with 0.2% (0.013 mol/L) DTT in the respective prefixative. Five samples were prefixed for 4 wk before homogenization. The homogenization time varied from 30 min to 48 hr. The cellular morphology was compared to directly smeared controls from the same samples. It was found that the cellular morphology was well preserved and best with the 3% carbowax in 60% ethanol. The specimen could be prefixed for up to 4 wk before homogenization and the homogenization process could last from 30 min to 48 hr without any damaging effect on morphology. Furthermore, screening was made easy with the mucus lysed and its obscuring effect removed and the cells concentrated and evenly distributed. The method was versatile and could be of value in enhancing the detection rate of cancer in sputum.

Adenocarcinoma↗
PubMed1994

Changes in histological structure and microvasculature of the rat tongue after transection of the hypoglossal nerve.

This investigation was made on sequential changes in the tongue caused by unilateral transection of the hypoglossal nerve in the rat. These changes were examined on the basis of gross inspection of the lingual dorsal surface, histological aspects of the intrinsic muscle and interstitial tissues, morphological changes in the capillary loops of the filiform papillae utilizing plastic microcorrosion casts, and blood flux and number of erythrocytes in the lingual dorsum as determined by laser Doppler flowmetry. The period of examination following denervation of the hypoglossal nerve was divided into 3-5 days, 1, 2-3, 4-5, 6-7 and 66 weeks. The initial sign of histological change was an edematous change that later developed to atrophic change of the muscular element. This pathological change caused a change in volume on the lesion side of the tongue and finally formed a depression on the dorsal surface and a scallop-like lateral margin. Four to five weeks after denervation, the lesion half swelled, and its lingual apex elongated forward with a coving of the lingual median groove. The filiform papillae showed decreased keratinization, and interpapillary intervals were somewhat widened. Capillary loops in the papillae began to change, showing slight twistings at the tips of loops. Additionally, bulging, coiling and tortuosity were observed on both crura. The loops showed more complicated transformation, and little recovery was observed even 66 weeks after denervation. Blood flux in the dorsal mucosa decreased very slowly after a slight increase. This process seemed to be in proportion to the transformational complexity of the capillary loops in the filiform papillae. In conclusion, unilateral transection of the hypoglossal nerve, which is composed almost entirely of efferent neurons, caused edema and atrophic change in the intrinsic lingual muscle fibers with interstitial fibrosis in the lesion half of the tongue. Capillary loops in the filiform papillae were transformed markedly and successively by transection of the hypoglossal vasomotor neuron together with a slight decrease in blood flow in the dorsal mucosa. None of these changes recovered even at 66 weeks after transection.

Animals↗
PubMed1994

[The evaluation of the anti-shivering effect of tramadol during epidural anesthesia].

60 patients (except parturients) suffering from shivering after receiving epidural anesthesia were randomly divided into 2 equal groups. In order to evaluate the effect of Tramadol on the shivering, i.v. Tramadol (1 mg/Kg), in contrast to distilled water (20 ml) for the control group, was administered to the patients in the experimental group. We compared the arrest time between the two groups in addition to systolic blood pressure, diastolic blood pressure, heart rate, arterial O2 saturation, respiratory rate and body surface temperature. Furthermore, the degree of shivering was also compared sequentially. The systolic pressure of the control group declined significantly in the first 30 minutes (P < 0.05). The other data, including the diastolic pressure, heart rate, arterial O2 saturation, respiratory rate and body surface temperature, showed no significant difference (P > 0.05). The arrest time in the experimental group was 179 +/- 71.25 seconds in contrast to 2790 +/- 440.23 seconds in the control group, a large significant difference (P < 0.001). 10% of the patients in the experimental group experienced nausea or vomiting and 6.67% of the patients showed sedation which did not disturb consciousness level of psychomotor status. Since the exact mechanism of shivering during epidural anesthesia is not established, we sincerely hope more information about the effect to Tramadol on shivering can be uncovered.

Adult↗
PubMed1994

[Relation of HSP70 gene and spontaneously hypertension in rats].

The level of heat shock protein 70 messenger RNA was examined in aortic smooth muscle cells (ASMC) and hepatic tissue of Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The restriction fragment length polymorphism (RFLP) was also analysed in hepatic DNA. It was demonstrated that the basic level of heat shock protein 70 messenger RNA in ASMC and hepatic tissue of SHR were lower than that of the WKY rats. The extent of heat shock protein 70 messenger RNA accumulated in ASMC was higher in SHR than in WKY rats when the cells were heated by immersing the culture bottles in 42 degrees C water bath for 15 min and allowed to recover at 37 degrees C for 2 h. In contrast with WKY rats, the Bam HI restricted bepatic DNA showed that a fragment about 5.6 kb was lost in heat shock protein 70 gene from hepatic DNA of SHR. The results suggest that the ASMC of SHR is more sensitive to heat stress than that of WKY rats and the changes of heat shock protein gene sequence may be related to genetic hypertension.

Animals↗
PubMed1994

[Transcription of HSP 70 gene induced by pressure overload in left ventricule of rats].

The changes of heat shock protein 70 (HSP70) messenger RNA was examined in rats after abdominal aortic partial ligation. Four hours after ligation, the systemic arterial pressure was increased and thereafter maintained at a high level. The ratio of left ventricule weight to body weight began to increase at the third day and increased by 59%, comparing with that of the sham-operated rats at 4 w. Accumulation of HSP 70 mRNA was observed at 4 h and maintained at high level at 1 d, 2 d, 1 w and then gradually disappeared there after. The above experimental results suggest that transcription of HSP 70 gene was induced at an early stage of cardiac hypertrophy caused by pressure overload.

Animals↗
PubMed1994

[The depressor effect of intracerebroventricular injection of BQ123 and endothelin (ET)--antiserum on hypertensive rats produced by aorta stenosis and hypersaline uptake].

An experimental model of hypertensive rat was made by abdominal aorta stenosis and hypersaline uptake. The blood pressure was significantly decreased by intracerebroventricular injection (i.c.v.) of BQ123 a potent antagonist of ET-1 receptor, in a dose-dependent manner. Negative chronotropic effect on the heart was produced by high dose of BQ123, while the depressor effect was produced by i.c.v. ET-antiserum. These results indicate that endothelin in CNS may play an important role in the pathological physiology of hypertension.

Animals↗
PubMed1994

Role of regulatory peptide in pathogenesis of shock.

The present study evaluated the pathogenetic roles of three kinds of regulatory peptide. The results showed that (i) plasma endothelin (ET) level elevated significantly in septic shock rats, persistent intravenous drip of low doses ET caused development of shock state in normal rats and the irreversible outcome of light hemorrhagic shock. Furthermore, i. v. administration of specific ET-antiserum was significantly effective to septic shock rats. (ii) Plasma calcitonin gene-related peptide (CGRP) increased by 260% in septic shock rats, i. v. drip of low doses CGRP both in early and late sepsis were effective to shock rats. (iii) Angiotensin-II (ANG-II) contents of heart and aorta increased dramatically both in early and late septic shock, and inhibiting its increase with Captopril in late sepsis significantly improved the shock state, but results were inverse in early sepsis. It could be concluded that ET was one of the most important factors participating in the pathogenesis of shock, CGRP had a compensatory regulatory role in shock and the role of tissue ANG-II was different during different periods of shock.

Angiotensin II↗
PubMed1994

[The protective effects of metallothionein on membrane proteins against endothelin--electron paramagnetic resonance spin labelling study].

Using EPR spin labelling 5 NS, 16 NS (for fatty acids) and MSL (for proteins), the changes in lipid fluidity and protein conformation in the ghost erythrocyte membrane of rat treated by endothelin have been studied. The results showed that the lipid fluidity in both of the polar region and the hydrophobic core in the membranes was not altered by endothelin at the concentration of 1 x 10(-9), 1 x 10(-8) and 1 x 10(-7) mol/L, but the ratio of S/W of membrane proteins was significantly changed by endothelin at 5 x 10(-9) and 1 x 10(-7) mol/L. This means that endothelin at the dosages used did not affect the membrane lipids but did alter protein conformation. Metallothionein (1 x 10(-5) mol/L) could attenuate this change and protect membrane proteins from endothelin. However, there is no effect of metallothionein on membrane proteins.

Animals↗
PubMed1993

Retrospective investigation of intermittent bolus intrathecal morphine for cancer pain patients.

One hundred patients with intolerable cancer pain were treated with intrathecal bolus injections of morphine(IT morphine). The study began 2 days later after port-A cath implantation and continued during the 12 weeks follow-up period. During the investigation, the dosages, pain intensity, side effects, complications, activity and acceptibility were recorded. Initially, the morphine test does(0.2mg) resulted in pain relief for 8-26 hrs (mean 13.4 hrs). Then, changing the morphine dosages or frequency of injections were relied upon the effect of the opiate to provide 24 hrs pain relief. The mean morphine requirements were 0.32mg in 1st week, 0.44mg in 4th week, 1.25mg in 8th week and 1.43mg in 12th week. The mean morphine dose before IT treatment was 36.4mg. The vast majority of patients' pain intensity decreased prominently after IT morphine treatment. But pain was aggravated in the 12th week although the morphine dose increased. Side effects were minimal, and only one patient suffered from meningitis. Complications included 8 patients with port-A system dysfunction, one with anterior spinal artery syndrome, and one case of cauda equina syndrome. Activity improved significantly and all patients accepted the kind of treatment though some patients did not experience completely satisfactory relief from pain. Intrathecal morphine therapy uses only small amounts of opiate to achieve the optimal level of pain relief. So it offers a beneficial treatment option to patients whose pain has become intolerable or who have poor responsiveness to systemic narcotics.

Adolescent↗