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R Du

Publications and source records attributed to R Du.

At least 37 records · Page 2Linked to original sources
PubMed2000

[The role of nitric oxide in the pathogenesis of portal hypertension].

OBJECTIVE: To investigate the role of nitric oxide in the pathogenesis of portal hypertension. METHODS: We measured the portal venous pressure of 75 patients via a catheter and detected the levels of plasma endotoxin and NO(2)(-)/NO(3)(-). RESULTS: The mean levels of plasma endotoxin and NO(2)(-)/NO(3)(-) (0.249 +/- 0.112 Eu/ml and 55.9 +/- 26.2 micromol/L) in portal hypertensive patients were significantly higher than those in the controls, and the highest values were observed in the portal venous blood. The mean portal venous pressure of the portal hypertensive patients was 35.5 +/- 4.4 cm H(2)O and was positively correlated with the levels of NO(2)(-)/NO(3)(-) (n = 25, r = 0.55, P < 0.01). Positive correlation existed between them during the postoperative period (r = 0.57, P < 0.05). There was a negative correlation between the levels of albumin and NO(2)(-)/NO(3)(-) (n = 75, r = -0.35, P < 0.01), and the mean levels of NO(2)(-)/NO(3)(-) were 72.4 +/- 20.3 micromol/L in the patients with ascites, much higher than those (50.3 +/- 21.0 micromol/L) without ascites. CONCLUSIONS: The levels of plasma endotoxin and nitric oxide were elevated in patients with portal hypertension, and NO might play an important role in the abnormal elevation of portal venous pressure and the damage to liver function.

Endotoxins↗
PubMed2000

[Anatomical basis of autonomic nerve-preserving radical resection for rectal cancer].

OBJECTIVE: To clarify anatomical basis of autonomic nerve-preserving radical resection for rectal cancer. METHOD: Of 10 cadavers, 4 were male and 2 female. Four had hemisected pelvis in the mid-sagittal plane without damaging the retrorectal anatomy. All stages of each dissection were recorded photographically. RESULTS: Hypogastric nerves were identified. The superior hypogastric plexus is the direct extension of the aortic plexus below the aortic bifurcation. It lies immediately behind the peritoneum and descends over the anterior surface of the 5th lumbar vertebra in the retroperitoneal tissue. The superior hypogastric plexus ends by bifurcating into the right and left hypogastric nerves. The two hypogastric nerves diverge from each other at about the level of the sacral promontory and run down and forward along the walls of the pelvis in the lamina of the pelvic fascia closest to the peritoneum. Both of them are strong fibres with white-grey and reticular appearance and well located just below and close to the aortic bifurcation. And after bifurcation each of them also gives rise to several branches. But it is difficult to identify the pelvic splanchnic nerves in complete samples. In mid-sagitted samples they take origin from the second to fourth sacral ventral rami just after the sacral nerves have emerged from the pelvic sacral foramina. They always form plexus at the lateral ligament and are crossed by middle rectal artery. CONCLUSIONS: It is not very difficult to preserve the hypogastric nerves to spare functions in resection for rectal cancer to the anatomical knowledge of the pelvic autonomic nerves. When the pelvic splanchnic nerves are to be preserved, dissection must be cautious at the level of the lateral ligment on the side of nerve-preservation. The operation should be performed near the rectum as close as possible to achieve functional preservation.

Autonomic Pathways↗
PubMed2000

Expression of alpha1 adrenoceptor subtypes mRNA in hepatic tissues of cirrhotic patients with portal hypertension.

OBJECTIVE: To investigate the expression of mRNA of alpha(1) adrenoceptor in the hepatic tissues of cirrhotic patients with portal hypertension. METHODS: Semi-quantitative reverse transcription and polymerase chain reaction (RT-PCR) was used in 12 hepatitis virus B-related cirrhotic patients with portal hypertension and 15 controls who had no history of portal hypertension. In these patients, routine liver biopsy was performed. Special alpha(1) adrenoceptor subtype product and internal standard GAPDH product were both amplified by RT-PCR. The ratio of their integral optical density (IOD) was calculated as the relative expression of the alpha(1) adrenoceptor subtypes. RESULTS: The relative mRNA expression of alpha(1a) adrenoceptor subtype in the hepatic tissues was significantly lower in the cirrhotic patients (0.26 +/- 0.12) than in the controls (0.86 +/- 0.38, P < 0.01). The relative mRNA expression of alpha(1b) adrenoceptor subtype in the hepatic tissues was also significantly lower in the cirrhotic patients (0.03 +/- 0.01) than in the controls (0.23 +/- 0.10, P < 0.01). Neither the cirrhotic patients nor the controls showed alpha(1d) adrenoceptor subtype in the hepatic tissues. The relative mRNA expression of alpha(1a) adrenoceptor subtype was significantly higher than that of alpha(1b) adrenoceptor subtype in the hepatic tissues of both cirrhotic patients and controls (P < 0.01). CONCLUSIONS: The alpha(1a) adrenoceptor mRNA expression predominates in both normal and cirrhotic hepatic tissues. The expression of alpha(1b) adrenoceptor is less marked and there is no expression of alpha(1d) adrenoceptor. The decreased expression of mRNA of alpha(1a) and alpha(1b) adrenoceptor may underlie the decrease of alpha(1) adrenoceptor proteins often seen in the hepatic tissues of cirrhotic patients, and may play an important role in the pathogenesis and maintenance of portal hypertension.

Adult↗
PubMed2000

[Melanoma antigen-3 expression in human hepatocellular carcinoma].

OBJECTIVE: To investigate the expression of melanoma antigen-3 (MAGE-3) mRNA in human hepatocellular carcinoma (HCC) and probe into the theoretical feasibility that MAGE-3 antigens can be developed as a new peptide vaccine for immunotherapy in HCC patients. METHODS: The expression of MAGE-3 mRNA in HCC tissues and the adjacent non-HCC liver tissues was studied using RT-PCR in 45 HCC patients. The results were compared with those of 16 cirrhotic patients and 12 patients whose liver tissues were pathologically normal. MAGE-3 mRNA positive PCR products were DNA sequenced in 3 HCC patients. The sequenced fragments of MAGE-3 cDNA were used as template by which a [alpha(32)P] labeled probe was synthesized and employed for Southern blot analysis. HLA class I-A and -B typing of 43 HCC patients were assayed by ELISA. RESULTS: Of the 45 HCC samples, 35 (78%) expressed MAGE-3 mRNA and six HCC adjacent tissues were also positive in MAGE-3 expression. Pathological examination showed cellular heteromorphism in these adjacent tissues. The non-HCC liver tissues from cirrhosis and normal liver samples were not MAGE-3 mRNA detectable. The DNA sequence confirmed that the target gene fragment in all of the 3 samples of PCR products was MAGE-3 cDNA. Southern blotting result confirmed that of RT-PCR assay. In HCC patients, the predominant types of HLA were A(2) (53.5%), A(11) (25.6%), A(24) (20.9%), A(33) (20.9%), B(13) (28.3%), and B(35) (23.2%). MAGE-3 mRNA expression in HCC showed no correlation with the level of serum AFP and the size of the tumor. CONCLUSIONS: MAGE-3 mRNA is expressed at a high percentage of HCC samples. This tumor rejection antigen may be used as peptide vaccine for immunotherapy of HCC patients. The phenomena that some non-HCC adjacent tissues with heteromorphism can express MAGE-3 like their paired HCC tissues indicate that the expression of MAGE-3 may be an indicator in the early stage of carcinogenesis of liver tissues.

Aged↗
PubMed2000

[Effects of urapidil and cimetidine on wedged hepatic venous pressure and systemic hemodynamics in cirrhotic patients with portal hypertension].

OBJECTIVE: To compare the effects of urapidil and cimetidine on portal pressure and systemic hemodynamics. METHODS: We observed the effects of urapidil (urapidil HCl, n = 15), cimetidine (n = 20) and placebo (0.9% sodium chloride, n = 10) on wedged hepatic venous pressure (WHVP), hepatic venous pressure gradient (HVPG), and systemic hemodynamics. RESULTS: Urapidil at a dosage of 25 mg intravenously reduced WHVP from 33.33 +/- 7.85 cm H2O to 23.75 +/- 6.83 cm H2O, the average value was 28.75% +/- 9.81% (P > 0.01); and HVPG from 21.92 +/- 2.34 cm H2O to 14.07 +/- 3.57 cm H2O, the average value was 35.81% +/- 8.71% (P < 0.01). The free hepatic venous pressure (FHVP) however was not changed significantly (P > 0.05). The heart rate was increased from 70 +/- 13 BPM to 79 +/- 21 BPM (P < 0.05), and the systolic blood pressure and the diastolic blood pressure were reduced from 122 +/- 40 mm Hg to 95 +/- 32 mm Hg and 75 +/- 17 mm Hg to 55 +/- 15 mm Hg respectively (P < 0.01). After cimetidine administered at a dosage of 400 mg intravenously, WHVP and HVPG were reduced from 34.25 +/- 7.34 cm H2O to 29.05 +/- 7.03 cm H2O and 23.14 +- 8.15 cm H2O to 17.13 +/- 4.28 cm H2O; and the average value was 15.18% +/- 8.64% and 26.00% +/- 12.19% respectively (P < 0.01). But heart rate, blood pressure and FHVP were not altered after use of cimetidine ( P > 0.05). In the control group (n = 10), WHVP, HVPG, FHVP, heart rate, as well as blood pressure were not changed after placebo treatment. CONCLUSIONS: Both urapidil and cimetidine could reduce WHVP and HVPG significantly in cirrhotic patients with portal hypertension, and the effect of the two agents on WHVP and HVPG was not obviously different (P > 0.05). However, the systemic hemodynamic effects induced by urapidil were more significant compared with cimetidine.

Adult↗
PubMed2000

[Effect of alginate purity on microencapsulated hepatocyte overgrowth in peritoneal transplantation].

OBJECTION: To study the effect of alginate purity on microcapsule overgrowth in peritoneal transplantation. METHODS: Alginate was purified by filtration and chloroform/butanol extraction. Using purified and crude alginate to make two kinds of microencapsulated hepatocytes (MHs), we transplanted 5 ml of each kind of MHs into the peritoneal cavities of rats. After 2 weeks, 1, 2, and 6 months, MHs were washed out to study overgrowth of MH, histology, enzyme and albumin of hepatocytes. Human lymphocytes transformation was measured by 3H-TdR incorporation with two kinds of alginate solutions. RESULTS: The amount of retrieved MHs was larger in the purified than in the crude ( P < 0.01). In the purified groups, most hepatocytes had normal features of morphology, enzymatic histochemistry, and albumin immunohistochemistry staining after one month of transplantation, but were damaged in the crude groups only 2 weeks later. Microcapsules were smooth, regular and had no overgrowth during 6 months in the purified but overgrowth one month later after transplantation in the crude. The liquid scintillation counting (cpm) was lower in the purified than in the crude. CONCLUSION: The purified alginate could reduce the overgrowth of MH and improve the function of hepatocytes significantly.

Alginates↗
PubMed2000

[Construction of plasmids expressing hepatitis E virus antigen fragments and their combinations].

OBJECTIVE: Several different regions of the HEV antigen were expressed in Escherichia coli and their immunological characteristics were simply evaluated. METHODS: Three coding sequences of immunodominant antigenic regions in structural protein of the hepatitis E virus (ORF2.1: 6287-6403nt, ORF2.2: 6743-7126nt, ORF3: full length of ORF3) were amplified by RT-PCR from the fecal supernatants of macaques experimentally infected with HEV. These three fragments were inserted into the pThioHisC expression vector separately or fused in line by (Gly)n short arms. After identified by DNA sequence analysis, these six recombinant plasmids were transformed into Escherichia coli, and immunology characteristics of expressed antigen fragments were evaluated by Western blotting. RESULTS: All six genes were successfully expressed in Escherichia coli. Western blotting assay showed that the recombinant proteins specifically reacted with the serum antibody from hepatitis E patient in various degrees. CONCLUSION: Artificial antigen based on strung epitopes provides a promising strategy for detection and prevention of HEV infection.

Antigens, Viral↗
PubMed1999

Distribution of two HIV-1-resistant polymorphisms (SDF1-3'A and CCR2-64I) in East Asian and world populations and its implication in AIDS epidemiology.

Chemokine receptor CCR2 and stromal-derived factor (SDF-1) are involved in HIV infection and AIDS symptom onset. Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3'A, can delay AIDS onset > or = 16 years after seroconversions. The protective effect of CCR2-64I is dominant, whereas that of SDF1-3'A is recessive. SDF1-3'A homozygotes also showed possible protection against HIV-1 infection. In this study, we surveyed the frequency distributions of the two alleles at both loci in world populations, with emphasis on those in east Asia. The CCR2-64I frequencies do not vary significantly in the different continents, having a range of 0.1-0.2 in most populations. A decreasing cline of the CCR2-64I frequency from north to south was observed in east Asia. In contrast, the distribution of SDF1-3'A in world populations varies substantially, and the highest frequency was observed in Oceanian populations. Moreover, an increasing cline of the SDF1-3'A frequency from north to south was observed in east Asia. The relative hazard values were computed to evaluate the risk of AIDS onset on the basis of two-locus genotypes in the east Asian and world populations.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Y-Chromosome evidence for a northward migration of modern humans into Eastern Asia during the last Ice Age.

The timing and nature of the arrival and the subsequent expansion of modern humans into eastern Asia remains controversial. Using Y-chromosome biallelic markers, we investigated the ancient human-migration patterns in eastern Asia. Our data indicate that southern populations in eastern Asia are much more polymorphic than northern populations, which have only a subset of the southern haplotypes. This pattern indicates that the first settlement of modern humans in eastern Asia occurred in mainland Southeast Asia during the last Ice Age, coinciding with the absence of human fossils in eastern Asia, 50,000-100,000 years ago. After the initial peopling, a great northward migration extended into northern China and Siberia.

Africa↗
PubMed1999

[Measurement of liver volume and its clinical significance in cirrhotic patients].

OBJECTIVE: To evaluate whether, preoperative measurement of liver volume is of value to the evaluation of tolerance to operation and long-term prognosis in cirrhotic patients with portal hypertension. METHODS: We assessed liver volume in 18 cirrhotics and 31 noncirrhotic controls with 3-dimensional shaded surface display by CT twin. RESULTS: The liver volume in controls was positively correlated to the height (r = 0.42, P < 0.05). The average of liver volume in controls was (1 070.68 +/- 227.52) cm(3) and was different from that of cirrhotics (797.02 +/- 135.11) cm(3) (P < 0.05). Liver volume of cirrhotic patients with portal hypertension was related to their Child classification. The liver volume of patients in Child C group was significantly smaller than that of patients of Child B group. CONCLUSIONS: The patients with smaller liver volume are likely complicated by encephalopathy after shunting procedure. However, the liver volume is not significantly correlated with portal blood flux and portosystemic shunt index.

Adult↗
PubMed1999

[Plasma level of glucagon in cirrhotic patients with portal hypertension during operation of portacaval shunts].

OBJECTIVE: To investigate the plasma level of glucagon in cirrhotic patients with portal hypertension during operation of portacaval shunts. METHODS: Plasma level of glucagon in the portal venous, peripheral venous and arterial blood in cirrhotic patients (n = 16) and control patients (n = 16) was measured by radioimmunoassay respectively. RESULTS: The glucagon ratio (pg/ml) of the hepatic cirrhosis group before, during after operation 3 days after operation, 7 days after operation was observed portal venous blood: (189.2 +/- 58.7) pg/ml, (196.1 +/- 54.2) pg/ml vs. (101.9 +/- 44.8) pg/ml, (98.2 +/- 34.1) pg/ml (P < 0.01); peripheral venous blood (184.1 +/- 48.2) pg/ml, (187.5 +/- 42.8) pg/ml vs. (102.4 +/- 34.7) pg/ml, (95.2 +/- 24.9) pg/ml (P < 0.01); arterial blood: (186.3 +/- 51.3) pg/ml, (183.5 +/- 54.2) pg/ml vs. (103.4 +/- 36.3) pg/ml, (93.9 +/- 30.6) pg/ml (P < 0.01). The portal vein pressure was positively correlated to the plasma level of glucagon in portal venous blood of cirrhosis (r = 0.57, P < 0.01). CONCLUSIONS: Hyperglucagonemia may be caused by the decreased glucagon metabolism in cirrhotic liver and hypersecretion of pancreas and the gastrointestinal tract. Hyperglucagonemia may be amended after portacaval shunts.

Adult↗
PubMed1999

[The levels of renin activity, angiotensin converting enzyme and angiotensin II in cirrhotic patients with ascites undergoing portacaval shunt].

OBJECTIVE: To investigate the changes of plasma renin activity (PRA), angiotensin converting enzyme (ACE), angiotensin II and portal venous pressure (PVP) in cirrhotic patients with ascites undergoing portacaval shunt. METHODS: Serum PRA, ACE, A II levels in portal vein, artery, peripheral vein and PVP were measured in 16 cirrhotic patients with ascites before and after portacaval shunts and in control group of 16 cases of gastrointestinal carcinoma. By light colorimetric analysis and radio-immunization assay. RESULTS: PRA, ACE, A II levels and PVP of pre- and after portacaval shunt were significantly higher in cirrhotic patients than the control group (P < 0.05), and they were significantly decreased after the shunt in the cirrhotic patients (P < 0.05). The PVP was in positive correlation to the levels of serum ACE in cirrhotic patients (r = 0.48, P < 0.01). CONCLUSIONS: The levels of serum PRA, ACE, A II and PVP decreased significantly in cirrhotic patients with portal hypertension after portacaval shunts. It may be major causes of ascites disappearance in cirrhotic patients after portacaval shunt.

Adult↗
PubMed1998

Models of protein interactions: how to choose one.

BACKGROUND: There have been many attempts to approximate realistic protein interaction energies by coarse graining (i.e. considering interactions between amino acids rather than those between atoms). In particular, many 20-letter models have been derived (corresponding to the 20 naturally occurring amino acids). Because such models remain computationally infeasible, many two-letter models have been proposed as further simplifications. The choice of which model to use remains arbitrary, however. In this work, we formulate the framework within which the quality of approximate interaction potentials with respect to folding can be defined explicitly. RESULTS: Using a recently proposed criterion for comparing interaction matrices, we compare various 20 x 20 interaction matrices and obtain the two-letter model that most closely approximates each 20 x 20 matrix. We find that there are considerable differences among the 20 x 20 matrices. In particular, some matrices are much more similar to the hydrophobic model than others. Furthermore, we find that although the best two-letter approximation of a 20-letter model is a significantly better approximation than a random two-letter model, it is still a poor approximation of realistic protein interactions. CONCLUSIONS: The determination of the best two-letter approximations of various 20-letter models of protein interaction energies reveals the degree to which hydrophobic interactions dominate in each of the models and hence in proteins.

Models, Chemical↗
PubMed1998

Monitoring working memory load during computer-based tasks with EEG pattern recognition methods.

We assessed working memory load during computer use with neural network pattern recognition applied to EEG spectral features. Eight participants performed high-, moderate-, and low-load working memory tasks. Frontal theta EEG activity increased and alpha activity decreased with increasing load. These changes probably reflect task difficulty-related increases in mental effort and the proportion of cortical resources allocated to task performance. In network analyses, test data segments from high and low load levels were discriminated with better than 95% accuracy. More than 80% of test data segments associated with a moderate load could be discriminated from high- or low-load data segments. Statistically significant classification was also achieved when applying networks trained with data from one day to data from another day, when applying networks trained with data from one task to data from another task, and when applying networks trained with data from a group of participants to data from new participants. These results support the feasibility of using EEG-based methods for monitoring cognitive load during human-computer interaction.

Adult↗
PubMed1998

The pathogenetic role of endogenous angiotensin II in stress ulcer in obstructive jaundice rats.

OBJECTIVE: To investigate the pathogenetic role of endogenous angiotensin II (Ang II) in the mechanism of stress ulcer in obstructive jaundice rats and to detect the effect of angiotensin converting enzyme inhibitor (ACEI) on stress ulcer in obstructive jaundice rats. METHODS: After common bile duct ligation (CBDL) in Wistar rats, the content of plasma and gastric mucosal Ang II, gastric mucosal blood flow (GMBF) and gastric mucosal damage were measured, and the relationship among them was analyzed. RESULTS: The plasma Ang II contents increased much more significantly at 1, 3, 7 and 14 days following CBDL than those in non-CBDL rats (P < 0.05, < 0.01, < 0.01 and < 0.01, respectively). Within 120 minutes following cold-restraint stress, plasma and gastric mucosal Ang II contents were elevated, GMBF decreased, and ulcer index and gastric mucosal damage increased more significantly than those in non-cold-restraint stress rats (P < 0.05, < 0.05, < 0.01, < 0.01 and < 0.05, respectively). Administration of an ACEI, enalaprili, to CBDL rats (5 mg.kg-1.day-1, orally for two days) before stress reduced both the plasma and gastric mucosal Ang II levels, inhibited the decrease of GMBF and decreased ulcer index and gastric mucosal damage (P < 0.001, < 0.01, < 0.01, < 0.01 and < 0.05, respectively). CONCLUSION: The endogenous Ang II plays a significant pathogenetic role in the development of stress ulcer in obstructive jaundice rats, and ACEI may prevent stress ulcer.

Angiotensin II↗
PubMed1998

Surgical treatment of atrial fibrillation with maze procedure by radiofrequency ablation.

OBJECTIVE: To compare the results of treatment of atrial fibrillation (Af) with maze procedure by radiofrequency in 25 patients undergoing mitral valve replacement operation (MVRO) (treatment group) with those in 25 patients undergoing MVRO only (control group). METHODS: The maze procedure modified was completed by radiofrequency ablation with macroscopy during MVRO in the treatment group, whereas the patients in the control group underwent MVRO only. No one in the two groups took antiarrhythmic drugs before and after operation. RESULTS: The heart rhythm became stable sinus rhythm in 22 of 25 patients of the treatment group after operation and the success rate was 88.0%. Af recurred in none of the 22 patients during the follow-up for 3-24 months. In the control group, 5 patients showed transient sinus rhythm, but Af recurred when they left hospital. CONCLUSIONS: Maze procedure by radiofrequency ablation is an effective method to cure Af and its success rate was the same as that of surgical incision and cryolesion. But the former took 10-15 minutes only with light damage of atrial muscle and no bleeding, whereas the latter took 1-1.5 hours.

Adult↗
PubMed1998

Serum levels of epinephrine and norepinephrine in cirrhotic patients with portal hypertension.

OBJECTIVE: To investigate the role of catecholamines in the pathogenesis of portal hypertension. METHODS: Serum epinephrine (E) and norepinephrine (NE) concentrations in the peripheral vein, portal vein and superior vena cava (SVC) were measured by high pressure liquid chromatography in 38 portal hypertensive patients, 28 idiopathic hypertensive patients and 34 controls, respectively. RESULTS: Peripheral venous E concentrations in portal hypertensive patients and controls were 57.5 +/- 37.4 ng/L and 23.5 +/- 11.2 ng/L, respectively (P < 0.01), and peripheral venous NE concentrations were 451.1 +/- 381.2 ng/L and 183.0 +/- 83.3 ng/L, respectively (P < 0.01). Compared with controls, peripheral venous E (54.9 +/- 39.9 ng/L vs 23.5 +/- 11.2 ng/L, P < 0.01) and NE (524.3 +/- 219.9 ng/L vs 183.0 +/- 83.3 ng/L, P < 0.01) in idiopathic hypertensive patients were also significantly increased. E and NE in SVC, portal vein and peripheral artery in portal hypertensive patients were also increased, but only the elevation of E in SVC was statistically significant (207.2 +/- 55.4 ng/L vs 83.7 +/- 46.7 ng/L, P < 0.05). CONCLUSION: Our results reveal significant metabolic disorders of E and NE in portal hypertensive patients, which may play an important role in the pathogenesis of portal hypertension.

Adult↗