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Biomedical subjects

S Yuan

Publications and source records attributed to S Yuan.

At least 145 records · Page 8Linked to original sources
PubMed1995

[Clinicopathologic features and diagnosis of mixed type hepatocellular carcinoma].

Hepatoma cases (n = 130) were analyzed by means of histochemical and immunohistochemical stainings. There were 99 cases of hepatocellular carcinoma (HCC), 15 cholangiocarcinoma (CC), and 16 combined HCC and CC (HCC+CC). The clinical features and the cases accompanied with hepatitis and/or liver cirrhosis in the non-tumor liver tissue of HCC+CC cases were intermediate between HCC and CC cases. Histologically, in HCC+CC cases, there were 4 cases with trabecular, 4 with pseudoglandular, 3 with solid type. In these 11 cases, the CC occupied less than 10% of the neoplasm. These cases were designated as HCC+CC type I. There was no obvious stromal fibrosis. The rest 5 cases of HCC+CC cases showed tubular carcinoma in which the CC occupied more than 10% of the tumor. These cases were designated as HCC+CC type II. There was significant fibrosis in the stroma. In all HCC+CC cases only the CC region was positive for mucin and EMA staining. Nearly 70% of the HCC+CC cases had intracytoplasmic glycogen in the HCC area. Transition areas between HCC and CC in both type I and type II HCC+CC cases were observed and they were mucin negative but EMA positive. In conclusion, HCC+CC has both HCC and CC regions with the characteristics of HCC and CC, respectively. Histochemical mucin staining and immunohistochemical EMA staining are helpful in the detection and diagnosis of the HCC+CC.

Adult↗
PubMed1995

Composite acupuncture treatment of mental retardation in children.

128 children of mental retardation were diagnosed in accordance with the diagnostic standards proposed by WHO in 1985. The patients were treated compositely with acupuncture, auriculo-acupoint pellet pressure and herbal plasters on acupoints, bringing about improved mental developments in intelligence quotient (IQ) and social adaptation behaviour (SAB), as evidenced by recognized intelligence tests for children.

Acupuncture Points↗
PubMed1995

Morphometric evaluation on myocardial protection of cold crystalloid versus warm blood cardioplegia.

Twenty patients undergoing open-heart valve replacement were divided randomly into two groups in this study; intermittent perfusion of cold crystalloid (St. Thomas Hospital solution) with hypothermic cardiopulmonary bypass (CPB) (hypothermic group) and continuous administration of warm blood cardioplegia with normothermic CPB (normothermic group) respectively. Tissue samples were taken from the right atrium before weaning from CPB and from the right appendage 30 minutes after removal of the cross-clamp. The results of pathological study in these two groups were as follows: the structural alterations were most severe during the ischemic period in the hypothermic group. Damages of the myocardial mitochondria examined with transmission electron microscope were found more severe in the hypothermic group than in the normothermic group, and in the reperfusion period than in the ischemic period. Loss of integrity of the mitochondrial membrane could be noted during reperfusion in the hypothermic group. The surface to volume ratios of mitochondria of each period of the two groups were calculated by computerizing the microphotographs of the myocardium. It was shown that the average of the surface to volume ratios was smallest in the reperfusion period in the normothermic group. It seemed that the volumes of the mitochondria were larger in the warm group than in the cold one. Probably the results were due to more severe damages of the mitochondrial membranes in the hypothermic group, which led to the release of the contents out of the mitochondria while in the normothermic group, the sodium-pump was disordered and it made the mitochondria swell. Pathologically, blood cardioplegic perfusion with the use of normothermic CPB is a feasible method for myocardial protection in open-heart surgery.

Bicarbonates↗
PubMed1995

[Long-term effect of extended parietal cell vagotomy on patients' nutrition and digestive function].

In this study, 36 patients undergoing extended parietal cell vagotomy (EPCV) were compared with 30 patients with subtotal gastrectomy 7-14 years after surgery. The patients' nutritional status, gastric sectretion, gastrointestinal motility and intestinal absorption function were evaluated. The nutritional status was generally less satisfactory in 33. 3% patients with anaemia after gastrectomy and decrease of body weight in 54%. The patients after EPCV were all in good nutritional status, with no anemia; 56% of them had a body weight increase of more than 3kg. Therefore, the rationality of EPCV was estalished.

Adult↗
PubMed1995

[The differentiation-inducing effect of tanshinone and retinoic acid on human cervical carcinoma cell line in vitro].

The differentiation-inducing activity of tanshinone (TAN) and all-trans-retinoic acid (RA) was studied in vitro on a human cervical carcinoma cell line, ME180. The tumor cells were treated with TAN or RA in DMSO (final concentration 0.02%, V/V) on 4 successive days. Cells treated with the same concentration of DMSO alone served as control. Morphologic studies with light and transmission electron microscopy showed that the cells treated with both TAN and RA became well-differentiated. The cell growth, (as revealed by cell counting and 3H-TdR incorporation) was inhibited and the tumorigenicity in nude mice was reduced. No significant difference was observed between the cells treated with TAN and RA.

Abietanes↗
PubMed1995

Ultrastructure of parietal cells before and after extended parietal cell vagotomy in patients with duodenal ulcer and their complications.

Since 1979 we have treated 149 patients with duodenal ulcer by extended parietal cell vagotomy (EPCV). Electron microscopy of parietal cells from gastric body mucosa and gastric acid secretory test were carried out in 22 randomly selected patients before and after EPCV. It was shown that before EPCV the ultrastructure of parietal cells presented the feature of vigorous section identical to the hyperfunctional secretion of gastric acid. The ultrastructure of parietal cells presented the feature of acute depression of secretory function, which was identical to a significant reduction of secretory function of gastric acid 0.5-6 months after EPCV. Two to 10 years after operation, however, especially over 10 years after EPCV, the ultrastructural changes of parietal cells gradually returned to normal, but gastric acid secretion remained at a low level, without preoperative secretory capacities. The results of this study provide a histological basis for the application of extended parietal cell vagotomy in the treatment of duodenal ulcer and its complications.

Adult↗
PubMed1994

Radioimmunolocalization of human pancreatic carcinoma xenograft by 99mTc-labeled YPC3 monoclonal antibody.

Monoclonal antibodies specific to tumor cells may be a useful tool for the diagnosis and treatment of carcinomas. In this study, YPC3 mAb, a specific monoclonal antibody against the human pancreatic carcinoma cell line Capan-2, was labeled directly with 99mTc after being pretreated with 2-mercaptoethanol. The radiolabeling efficiency was found to be high (88%-95%) and the immunoreactivity retained, as assessed by immunohistochemistry and enzyme-linked immunosorbent assay. The biodistribution of 99mTc-YPC3 mAb in nude mice bearing Capan-2 pancreatic carcinoma xenografts was studied and compared with that of labeled mouse immunoglobulin G(99mTc-nmIgG). The xenograft uptake values per gram of tissue 6 h and 24 h after injection of 99mTc-YPC3 mAb were found to be, respectively, 4.72%ID/g and 8.42%ID/g, and the tumor/blood ratios 1.16 and 2.24. At 6 h and 24 h after injection of 99mTc-nmIgG, the uptakes were 2.89%ID/g and 1.80%ID/g, and the tumor/blood ratios 0.84 and 1.02 respectively. External imaging by single-proton emission computed tomography, 24 h after injection of 99mTc-YPC3 mAb, revealed clear scintigraphic visualization of Capan-2 xenografts, whereas injection of 99mTc-nmIgG did not. This study suggests that 99mTc labeling of monoclonal antibody YPC3 might be of practical value in localization diagnosis of human pancreatic carcinoma.

Animals↗
PubMed1994

The effect of prostaglandin E2 and indomethacin on the cytotoxic response to mycobacterial antigens.

The effect of prostaglandin E2 and indomethacin on the generation of cytotoxic T-lymphocytes in response to Mycobacterium tuberculosis (MTB) antigens was compared between healthy controls and rheumatoid arthritis patients. Peripheral blood mononuclear cells (PBMC) from 16 healthy individuals and 15 RA patients were stimulated for 7 days with an irradiated, sonicated preparation of MTB in the presence or absence of PGE2 or indomethacin and assayed for cytotoxic activity on autologous target cells prepulsed with MTB. The mean cytotoxic activity generated was lower in patients than in controls. Exogenous PGE2 suppressed the cytotoxicity directed against MTB pulsed targets in 12 of 16 controls, but in only 1 of 11 patients. Indomethacin enhanced this cytotoxicity in only 2 of 16 controls but in 6 of 10 RA patients. When effector cells were derived from the synovial fluid, PGE2 again had no effect and indomethacin enhanced the cytotoxicity. Our data suggest that the depressed cytotoxic response of RA patients to MTB may be due to the production of endogenous PGE2. Cyclooxygenase inhibitors commonly used in the treatment of RA may influence MTB induced cytotoxicity in patients. In addition to their anti-inflammatory effects within the joint, non-steroidal anti-inflammatory drugs may potentially enhance cytotoxic reactions which are induced by antigens, such as MTB cross-reactive heat shock proteins.

Antigens, Bacterial↗
PubMed1994

Effect of dofetilide on cardiac repolarization in patients with ventricular tachycardia. A study using simultaneous monophasic action potential recordings from two sites in the right ventricle.

Monophasic action potentials (MAP) were simultaneously recorded from the right ventricular (RV) apex (RVA) and the outflow tract (RVOT) before and after an infusion of dofetilide in 10 patients with documented ventricular tachycardia. After the drug infusion, the MAP duration (MAPd), repolarization time, and corrected QT interval were significantly prolonged during sinus rhythm, RV pacing, and RV extra stimulation. The prolongation of MAPd at 90% repolarization during RV pacing at a cycle length of 500 ms was 31 +/- 6 ms (13%) and 26 +/- 7 ms (11%) at RVA and RVOT, respectively. The ventricular effective refractory period was significantly prolonged by 33 +/- 9 ms (13%) and 22 +/- 7 ms (9%) at driving cycle lengths 600 and 500 ms, respectively. The MAPd shortening with decreasing diastolic time intervals was significantly diminished by dofetilide in early extra beats during RV extra stimulation, suggesting a relatively more pronounced effect of this drug at the early diastolic phase. The dispersion of repolarization, defined as the difference in MAPd between RVA and RVOT, and the activation time were not significantly changed. In conclusion, acute administration of dofetilide in patients with ventricular tachycardia significantly prolonged the time intervals of ventricular repolarization and refractoriness in a parallel fashion, without affecting intraventricular conduction. The effect of dofetilide on MAPd prolongation appeared not to be reverse use-dependent in this study in humans. These results verify the selective class III antiarrhythmic property of dofetilide and warrant further studies in patients.

Action Potentials↗
PubMed1994

Monophasic action potentials: concepts to practical applications.

Monophasic action potential (MAP) recordings reproduce the repolarization time course of intracellular action potentials with high accuracy and provide precise information on the local activation time. With the advantage of in vivo application and the development of the safer and simpler contact catheter technique, MAP recording has become the method of choice for evaluating myocardial repolarization changes. This review aims to provide information on practical application of MAP recording in the clinical setting. MAPs can easily be recorded from the endocardium with the contact catheter technique in the electrophysiology laboratory and from the epicardium with electrode probes during open heart surgery. The technical aspects are described in detail. The rate dependence of myocardial excitability and repolarization and the effect of antiarrhythmic drugs on MAP duration and effective refractory period are thoroughly reviewed. The use of MAPs in detecting myocardial ischemia, in studying early afterdepolarization and triggered arrhythmias, in measuring dispersion of repolarization, in identifying intracardiac conduction and the development of the T wave, and in verifying the arrhythmogenic effect of mechanoelectric feedback are presented. Computerized automatic analysis of MAPs and the limitations of the MAP technique are also discussed.

Action Potentials↗
PubMed1994

Interactions of plasma proteins with a novel polysaccharide surfactant physisorbed to polyethylene.

A polysaccharide surfactant, dextran-[1,6 bis(2-hydroxypropyl-1-amine)hexane]-dextran, (D-H-D) was prepared by reacting dextran (Mw = 8200) with epichlorohydrin followed by reaction with 1,6-hexanediamine. The D-H-D polymer product was characterized by gel permeation chromatography (GPC), and 13C-nuclear magnetic resonance spectroscopy (13C-NMR). D-H-D was physisorbed on polyethylene (PE) from aqueous solution, and the adhesion stability and resistance to protein adsorption was examined under static and dynamic flow conditions, using a modified rotating disk system. Modified surfaces were characterized by attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR), electron spectroscopy for chemical analysis (ESCA) and by water contact angles. Under applied shear stresses of up to 73 dyn cm-2, the adhesion of D-H-D on PE was sufficient to inhibit desorption by water (> 90% D-H-D on PE was retained) and 5% SDS surfactant solution (approximately 83% D-H-D retained), as determined by ATR-FTIR. Under similar shear stress conditions, albumin adsorption on D-H-D modified PE was reduced by over 90%, and protein adsorption from fresh human plasma was reduced by approximately 70% compared with unmodified PE. The results are discussed in terms of interfacial forces, and the suitability of this approach for studying protein-surface interactions and for developing a novel class of protein-resistant biomaterials.

Adsorption↗
PubMed1994

[Study on polymorphism of ribosomal RNA gene in Chinese Hans and Yis].

In the secondary constriction region of the short arm of human group D and group G acrocentric chromosomes there are tandemly repeated sequences of transcriptable segments and non-transcriptable spacers of rRNA genes. In the non-transcriptable spacer segments there is a polymorphic region with length variation. This paper reports the results obtained when the BamHI digested products of genomic DNA from 36 cases of Han nationality and those from 40 cases of Yi nationality were probed with a cDNA subprobe, pA(BE), which corresponds to the downstream one third of the 28S rRNA gene and is 1.6kb long with BamHI and EcoRI restriction sites at its two terminal respectively, using Southern blotting and molecular hybridization techniques. A total of 10 different restriction fragments were detected. Four fragments (7.9, 4.9, 4.0 and 1.2 kb) were seen in all subjects tested and the frequencies of six other polymorphic fragments in Hans and Yis (10.0, 9.4, 8.5, 6.7 6.0 and 3.0 kb) showed no significant difference when compared to each other. From the 10 different patterns of combination of restriction fragments four of them (1HY, 2HY, 3HY and 4HY) were detected in both Hans and Yis with no significant difference between their respective frequencies. Four other patterns (5H, 6H, 7H and 8H) were only seen in Hans with individual frequencies not high enough to be statistically significant. However, the statistical test for the combined frequencies of these four patterns showed highly significant difference between Hans and Yis (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

China↗