Biomedical subjects

Y P Wang

Publications and source records attributed to Y P Wang.

At least 19 recordsLinked to original sources

PubMed2002

Pain model and fuzzy logic patient-controlled analgesia in shock-wave lithotripsy.

Pain control in conscious patients was investigated using a push-button, demand-driven supply of drugs. A fuzzy logic patient-controlled analgesia (PCA) algorithm was compared with a conventional algorithm, for alfentanil administration in extracorporeal shock-wave lithotripsy. The conventional PCA algorithm used an initial dose of 0.25mg, a fixed infusion rate of 60 mg h(-1) and a fixed bolus size of 0.2 mg with a 1 min lockout. The fuzzy logic PCA algorithm used an initial dose of 0.25 mg, a changeable infusion rate and a bolus size of 0.1 or 0.05 mg. The infusion rate was adjusted according to a look-up table that accepted the button-pressing history over the last three lockout intervals. The look-up table was designed using fuzzy logic. The bolus size was adjusted according to the button-pressing history over the past two lockout intervals. Twelve patients were treated using conventional PCA, and thirteen were treated with PCA + fuzzy logic control (FLC). PCA + FLC patients consumed 45% less drug. Also, PCA + FLC patients had a mean delivery/demand ratio of 82%, compared with 60% in conventional PCA. When the pain intensity scale was analysed, PCA + FLC patients had acceptable pain intensity at 62%, compared with 44% in conventional PCA.

Adult↗

PubMed2001

Induction of lacI mutations in Big Blue Rat-2 cells treated with 1-(2-hydroxyethyl)-1-nitrosourea: a model system for the analysis of mutagenic potential of the hydroxyethyl adducts produced by 1,3-bis (2-chloroethyl)-1-nitrosourea.

We have investigated the genotoxic effects of 1-(2-hydroxyethyl)-1-nitrosourea (HENU). We have chosen this agent because of its demonstrated ability to produce N7-(2-hydroxyethyl) guanine (N7-HOEtG) and O(6)-(2-hydroxyethyl) 2'-deoxyguanosine (O(6)-HOEtdG); two of the DNA alkylation products produced by 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU). For these studies, we have used the Big Blue Rat-2 cell line that contains a lambda/lacI shuttle vector. Treatment of these cells with HENU produced a dose dependent increase in the levels of N7-HOEtG and O(6)-HOEtdG as quantified by HPLC with electrochemical detection. Treatment of Big Blue Rat-2 cells with either 0, 1 or 5mM HENU resulted in mutation frequencies of 7.2+/-2.2x10(-5), 45.2+/-2.9x10(-5) and 120.3+/-24.4x10(-5), respectively. Comparison of the mutation frequencies demonstrates that 1 and 5mM HENU treatments have increased the mutation frequency by 6- and 16-fold, respectively. This increase in mutation frequency was statistically significant (P<0.001). Sequence analysis of HENU-induced mutations have revealed primarily G:C-->A:T transitions (52%) and a significant number of A:T-->T:A transversions (16%). We propose that the observed G:C-->A:T transitions are produced by the DNA alkylation product O(6)-HOEtdG. These results suggest that the formation of O(6)-HOEtdG by BCNU treatment contributes to its observed mutagenic properties.

Animals↗

PubMed2001

Evidence that neurotensin mediates the central effect of leptin on food intake in rat.

Recent evidence suggests that leptin's action on food intake and body weight regulation is mediated by a number of orexigenic and anorectic neuronal systems in the hypothalamus. Our previous demonstration that central injections of leptin induce hypothalamic neurotensin (NT) gene expression in association with a reduced food intake and decreased body weight in rats indicates that NT, an anorectic peptide, is involved in mediating leptin's action on feeding and body weight regulation. To begin to examine the relative role of NT in this regard we evaluated the effects of NT antiserum (NT-AS) or NT receptor antagonist, SR 48692, on the satiety action of leptin in rats. In the first experiment, 3rd cerebroventricular (i.c.v.) administration of either 1 or 5 microl of NT-AS, 30 min prior to leptin (4 microg) injection, completely blocked the effects of leptin on food deprivation (FD)-induced feeding. In the second experiment, intraperitoneal (i.p.) administration of SR 48692 (40 microg/kg) also completely prevented leptin's satiety action on FD-induced feeding. These results showing the reversal of leptin's satiety action by either NT immunoneutralization or NT-receptor antagonism support our hypothesis that NT is involved in mediating leptin's action on feeding and further suggest that this neuropeptide is a quantitatively important component of the leptin sensitive neural circuitry.

Animals↗

PubMed2001

The CRP-cAMP complex and downregulation of the glnAp2 promoter provides a novel regulatory linkage between carbon metabolism and nitrogen assimilation in Escherichia coli.

In Escherichia coli, glnA (encoding glutamine synthetase) is transcribed from two promoters (glnAp1 and glnAp2). The glnAp1 is a sigma(70)-dependent promoter that is activated by the cAMP receptor protein (CRP). Under nitrogen-deficient growth conditions, glnAp1 is repressed by NtrC-phosphate. The downstream glnAp2 promoter is sigma(54)-dependent and is activated by NtrC-phosphate. Here, we show that glnAp2 expression is affected by different carbon sources and that the CRP-cAMP complex inhibits the glnAp2 promoter activity. Primer extension and KMnO4 footprinting analysis indicate that the inhibitory effect is at the transcriptional level in vivo. When glnAp2 is activated by NifA, a similar inhibitory effect by CRP-cAMP is observed. Site-directed mutagenesis and deletion analysis indicate that the characterized and putative CRP-binding sites located in the upstream region of the glnAp2 promoter are not essential for the inhibitory effect. CRP-cAMP inhibits sigma(54)-dependent glnAp2 strongly, by 21-fold. By activating glnAp1 and downregulating glnAp2, the overall effect of CRP-cAMP on glnA expression is an approximately fourfold reduction, which correlates with the reduction of gamma-glutamyl transferase activities in the cells. We propose therefore that a physiological role of CRP-cAMP activation of glnAp1 is to partially compensate for CRP-cAMP downregulation of glnAp2, allowing a low but non-negligible level of expression of the important genes transcribed from it. A novel regulatory linkage between carbon and nitrogen regulons is proposed.

Carbon↗

PubMed2001

Role of CD8(+) cells in the progression of murine adriamycin nephropathy.

BACKGROUND: Many studies have shown that interstitial inflammation in human and experimental renal disease is characterized by T-cell infiltration, but published data on the involvement of inflammatory cell subsets in progressive tubulointerstitial lesions are often conflicting. A previous study suggested a role for cytotoxic T lymphocytes in the damaging effect of CD4(+) T-cell depletion in murine adriamycin (ADR) nephropathy, a model of focal segmental glomerulosclerosis (FSGS), and tubulointerstitial inflammation. The aim of this study was to investigate the role of CD8(+) cells in this model. METHODS: Male BALB/c mice were treated with five intraperitoneal injections of anti-CD8 monoclonal antibody (mAb), beginning from five days after ADR treatment, when overt proteinuria was established. Seven mice in each of groups A (ADR + mAb), B (ADR only), and C (saline treated, age matched) were sacrificed at week 6. Changes in renal function and histopathological features were assessed. Tubulointerstitial inflammation and glomerular inflammation were examined immunohistochemically. RESULTS: mAb treatment reduced CD8(+) cell levels to <2% of normal in spleen. Proteinuria in group A was no different from that in group B at week 6, but was markedly higher than in group C. Creatinine clearance was significantly ameliorated by anti-CD8 treatment (71.8 +/- 4.9 microL/min vs. 29.2 +/- 2.8 in group B and 81.9 +/- 3.7 in group C). Morphometric analysis showed less FSGS in group A compared with group B (6.5 +/- 1.9 vs. 13.0 +/- 2.8, P < 0.001), as well as less tubular atrophy (indicated by increased ratio of tubule cell height to tubular diameter, 0.25 +/- 0.24 in group A vs. 0.04 +/- 0.02 in group B, P < 0.05). CD8 depletion also reduced interstitial expansion (6.3 +/- 2.2% vs. 16.4 +/- 3.1 in group B, P < 0.001) and fibrosis (P < 0.01). Macrophage infiltration in tubulointerstitium was less in group A than in group B (P = 0.052). The number of interstitial CD4(+) cells appeared to increase after anti-CD8 treatment, but was not statistically different between groups A and B. CONCLUSION: Anti-CD8 treatment protects against renal functional and structural injury in this murine model of chronic proteinuric renal disease.

Animals↗

PubMed2001

Fast LV motion estimation using subspace approximation techniques.

Cardiac motion estimation is very important in understanding cardiac dynamics and in noninvasive diagnosis of heart disease. Magnetic resonance (MR) imaging tagging is a technique for measuring heart deformations. In cardiac tagged MR images, a set of dark lines are noninvasively encoded within myocardial tissue providing the means for measurement of deformations of the heart. The points along tag lines measured in different frames and in different directions carry important information for determining the three-dimensional nonrigid movement of left ventricle. However, these measurements are sparse and, therefore, multidimensional interpolation techniques are needed to reconstruct a dense displacement field. In this paper, a novel subspace approximation technique is used to accomplish this task. We formulate the displacement estimation as a variational problem and then project the solution into spline subspaces. Efficient numerical methods are derived by taking advantages of B-spline properties. The proposed technique significantly improves our previous results reported in [3] with respect to computational time. The method is applied to a temporal sequence of two-dimensional images and is validated with simulated and in vivo heart data.

Algorithms↗

PubMed2001

Enhanced expressions and histological characteristics of intravenously administered plasmid DNA in rat lung.

Cationic liposome-mediated gene transfection is a promising method for gene therapy. In this study, the transfection efficiency and histological patterns were evaluated in rat lung after intravenous administration via femoral vein of naked plasmid DNA, naked plasmid DNA with pretreatment of DOTAP, and DOTAP-cholesterol-plasmid DNA complex. Plasmid DNA encoding bacterial LacZ gene was used. For quantification of LacZ gene expression, beta-galactosidase assay was performed. For histologic examination, X-gal staining and immunohistochemical staining for transfected gene products were performed. Pretreatment of DOTAP prior to the infusion of naked plasmid DNA increased transfection efficiency up to a level comparable to DOTAP-cholesterol-plasmid DNA complex injection. Transfected genes were mainly expressed in type II pneumocytes and alveolar macrophages in all animals. We conclude that the high transfection efficiency is achievable by intravenous administration of naked plasmid DNA with pretreatment of DOTAP, to a level comparable to DOTAP-cholesterol-plasmid DNA complex. In this regard, naked plasmid DNA administration with pretreatment of DOTAP could be a more feasible option for intravenous gene transfer than DOTAP-cholesterol-plasmid DNA complex, in that the former is technically easier and more cost-effective than the latter with a comparable efficacy, in terms of intravenous gene delivery to the lung.

Animals↗

PubMed2001

Relationship between phenotypes of cell-function differentiation and pathobiological behavior of gastric carcinomas.

AIM: To reveal the correlation between the functional differentiation phenotypes of gastric carcinoma cells and the invasion and metastasis by a new way of cell-function classification. METHODS: Surgically resected specimens of 361 gastric carcinomas(GC) were investigated with enzyme-, mucin-, and tumor-related marker immunohistochemistry. According to the direction of cell-function differentiation, stomach carcinomas were divided into five functionally differentiated types. RESULTS: (1) Absorptive function differentiation type (AFDT): there were 82 (22.7%) patients including 76 (92.7%) aged 45 years. Sixty-nine (84.1%) cases belonged to the intestinal type. Thirty-eight (46.3%) expressed CD44v6 and 9 (13.6%) of 66 male patients developed liver metastasis. The 5-year survival rate of patients in this group (58.5%) was higher than those with the other types (P<0.01). (2) Mucin secreting function differentiation type (MSFDT): 54 (15%) cases. Fifty-three (98.1%) tumors had penetrated the serosa, 12 (22.2%) expressed ER and 22 (40.7%) expressed CD44v6. The postoperative 5-year survival rate was 28.6%. (3) Absorptive and mucin-producing function differentiation type (AMPFDT): there were 180 (49.9%) cases, including 31 (17.2%) aged younger than 45 years. The tumor was more common in women (62, 34.4%,) and expressed more frequently estrogen receptors (ER) (129, 81.7%) than other types (P<0.01). Ovary metastasis was found in 12 (19.4%) out of 62 female subjects. The patients with this type GC had the lowest 5-year survival rate (24.7%) among all types. (4) Specific function differentiation type (SFDT): 13 (3.6%) cases. Nine (69.2%) tumors of this type derived from APUD system, the other 4 (30.7%) were of different histological differentiation. Sixty per cent of the patients survived at least five years. (5) Non-function differentiation type (NFDT): 32 (8.9%) cases. Nineteen (59.4%) cases had lymph node metastases but no one with liver or ovary metastasis. The 5-year survival rate was 28.1%. CONCLUSION: This new cell-function classification of GC is helpful in indicating the characteristics of invasion and metastasis of GC with different cell-function differentiation phenotypes. Further study is needed to disclose the correlation between the cell-functional differentiation phenotypes and the relevant genotypes and the biological behavior of gastric carcinoma.

Biomarkers, Tumor↗

PubMed2001

[Prokaryotic expression of recombinant grass carp growth hormone].

The recombinant plasmid containing a synthetic grass carp growth hormone cDNA was transformed into Escherichia coli BL21 (DE3) and expressed efficiently, induced by 1 mmol/L IPTG. 12.5% SDS-PAGE showed the molecular weight of new added protein in Escherichia coli BL21 (DE3) is consistent with that of grass carp growth hormone. The recombinant protein was composed of approximately 40% of the total bacterial proteins. The target protein was purified with Ni-NTA affinity column. Western-blotting conformed that recombinant protein could specifically react with antibody against grass carp growth hormone. ELISA-receptor assay showed the bioactivity of recombinant protein is consistent with that of nature grass carp growth hormone.

Animals↗

PubMed2001

Rapid recovery of spontaneous baroreflex after sevoflurane anesthesia in ambulatory surgery.

BACKGROUND: Although sevoflurane seems to have fulfilled the criteria of ideal anesthetic agent for ambulatory surgery, its effects on intraoperative alteration and postoperative recovery of arterial baroreflex have not been well documented. This study assessed the time required for patients anesthetized with sevoflurane to regain their baseline baroreflex after ambulatory surgeries. METHODS: Ten ASA class I female patients scheduled for minor gynecological operation (D&C) were enrolled in this study. Spontaneous baroreflex sensitivity (SBR) calculated by sequence analysis of beat-to-beat variations in systolic arterial pressure and R-R intervals was recorded before anesthesia (Baseline), during anesthesia (Anesthesia), five min after operation (Post-op 1) and ten min after operation (Post-op 2). Data obtained from Anesthesia, Post-op 1, and Post-op 2 was compared with the Baseline. RESULTS: SBR value determined in Baseline group (28.6 +/- 4.9 ms/mmHg) was significantly different from Anesthesia group (12.2 +/- 2.1 ms/mmHg) and Post-op 1 group (15.8 +/- 1.8 ms/mmHg). Patients regained their conscious baseline baroreflex sensitivity within ten min after sevoflurane was switched off. CONCLUSIONS: Sevoflurane anesthesia depresses SBR and provides a quick SBR recovery upon emergence.

Adult↗

PubMed2001

Lack of intravenous lidocaine effects on HRV changes of tracheal intubation during induction of general anesthesia.

BACKGROUND: Intravenous lidocaine has been widely used for suppressing the autonomic activation from tracheal intubation during induction of general anesthesia. Conventionally, researches of its effectiveness through assessment of heart rate and blood pressure changes obtained by common clinical methods result in the conclusions deduced of much controversy. Heart rate variability is a noninvasive measurement of autonomic regulation and is suitable for the study of this subject. METHODS: 36 ASA class I-II patients undergoing general anesthesia were divided into 3 groups. Besides induction agents, intravenous lidocaine was given 5 min before tracheal intubation in group A, 3 min before intubation in group B and nothing in group C. HRV spectral powers were measured at awake state, anesthetized state before tracheal intubation and anesthetized state after tracheal intubation by time frequency spectral analysis method and comparison was made between the three groups. RESULTS: The HRV spectral power in high frequency (HF) and mid-frequency (MF) power bands and their ratios (MF/HF) were not significantly different among the 3 groups during the 3 observation periods. CONCLUSIONS: There was no evidence to indicate the effectiveness of intravenous lidocaine on the autonomic regulation during tracheal intubation under the influence of induction agents used in general anesthesia.

Anesthesia, General↗

PubMed2001

Magnesium lithospermate B inhibits hypoxia-induced calcium influx and nitric oxide release in endothelial cells.

AIM: To investigate the inhibitory effect of magnesium lithospermate B (MLB) on hypoxia-induced elevation of intracellular calcium concentration ([Ca2+]i) and nitric oxide (NO) release in endothelial cells. METHODS: The cultured human umbilical vein endothelial cells (ECV304) were cultured for 30 min under 95 % N(2) and 5 % CO2. Cell injury was evaluated by dye exclusion test and lactate dehydrogenase (LDH) assay. [Ca2+]i was determined by Fura 2-AM. NO content was examined by the NO assay kit. Endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) mRNA expressions were measured by semi-quantitative RT-PCR. RESULTS: Cell viability was decreased from (93.0 +/- 2.6) % in normoxia to (85.5 +/- 2.1) % in hypoxia (P < 0.01), and LDH release was increased from (41 +/- 28) U/L in normoxia to (141+/-68) U/L in hypoxia (P < 0.01) in ECV304 cultured under calcium conditions. MLB 5 and 10 mg/L improved cell viability and inhibited LDH leakage in ECV304. In addition, hypoxia increased [Ca2+]i, NO release, and eNOS and iNOS mRNA expressions in ECV304 (P < 0.01). These increases could be inhibited by MLB 5 and 10 mg/L (P < 0.01), but they were unaffected by hypoxia under calcium-free conditions. CONCLUSION: MLB attenuates hypoxia-induced cell injury and inhibits hypoxia-induced increases of [Ca2+]i, NO release, and eNOS and iNOS mRNA expressions in ECV304 in Krebs'solution containing calcium. The decreases of NO production and eNOS mRNA expression are possibly associated with inhibition of extracellular calcium influx in MLB-treated ECV304

Biological Transport, Active↗

PubMed2001

Salvianolate inhibits proliferation and endothelin release in cultured rat mesangial cells.

AIM: To study the effects of salvianolate, an aqueous extract of Radix Salviae Miltiorrhizae, on the proliferation and endothelin release of cultured rat mesangial cells. METHODS: The proliferation of mesangial cells was determined in terms of [3H]thymidine uptake. The concentration of endothelin was measured by radioimmunoassay. The cytotoxicity of salvianolate was tested by tetrazolium (MTT) and lactic dehydrogenase (LDH) assay. RESULTS: Lipopolysaccharide (LPS) 10 mg/L increased the proliferation and endothelin release in cultured mesangial cells. When mesangial cells pretreated with 3, 10, and 30 mg/L of salvianolate were incubated for 4 h with LPS, salvianolate exhibited a concentration dependent inhibitory effect on proliferation and endothelin levels in the mesangial cells induced by LPS. Furthermore, the increased basal levels of mesangial cells proliferation and the endothelin release were also effectively inhibited by salvianolate 30 mg/L at 4, 8, and 12 h. Besides, no cytotoxicity of salvianolate was observed. CONCLUSION: These results indicate that salvianolate can inhibit mesangial cells proliferation, which may be related to the decrease of endothelin release.

Animals↗

PubMed2001

[Factors of laccase producing and fermentation conditions by a new white-rot fungus AH28-2].

White-rot fungus AH28-2, a newly isolated strain, produced effectively laccase by induction when grown on a synthetic medium. Aromatic compounds of low molecular weight had an inducing influence on laccase production and its isoenzyme compositions. The using of o-toluidine or syringic acid had the best inducing effect. Cu2+ concentration in medium had distinguished effect on laccase production. Enzyme activity was notably increased by Cu2+ and reached the maximum when Cu2+ final concentration was 5 mumol/L. Mn2+ inhibited the synthesis of laccase. Carbon and nitrogen limitation were not beneficial to laccase synthesis, while high nutrient organic medium was beneficial to the growth of cell and the synthesis of laccase. Using cellobiose as the sole carbon source, the highest level enzyme activity reached 82,923. 7 u/L under the condition of optimum fermentation with ABTS as substrate. This enzyme activity was 2.9-fold higher compared to the reported data on international references in recent years.

Basidiomycota↗

PubMed2001

The role of central arginine vasopressin in corticotropin releasing hormone-induced fever in rats.

The purpose of the present study was to investigate the role of central arginine vasopressin (AVP) in corticotropin releasing hormone (CRH) induced fever in the rat. Guide cannulae were inserted into the third ventricle and placed over the ventral septal area (VSA). The content of arginine vasopressin in the VSA of the brain was determined by radioimmunoassay. Colon temperature was monitored in lightly restrained rats by insertion of a catheter mounted thermistor probe 5 cm in the rectum. The results demonstrated that intracerebroventricular (icv) injection of CRH increased AVP level in the VSA and the colonic temperature of the rats. Microinjection of AVP V(1) antagonist into the VSA 10 min before CRH administration significantly enhanced CRH-induced febrile response, while AVP V(1) antagonist itself did not have a significant effect on the colonic temperature. Furthermore, injection of AVP into the VSA 5 min before CRH administration (icv) suppressed the fever evoked by CRH. These findings suggest that CRH is an important factor that stimulates the release of AVP in the VSA during fever, and endogenous AVP in the VSA has an antipyretic action on the CRH-induced fever.

Animals↗

PubMed2000

Differential change in cardiac baroreflex sensitivity estimated by sequence and spectral analysis during etomidate anesthesia.

Spontaneous baroreflex sensitivity, high-frequency gain, (0.15-0.35 Hz), and mid-frequency gain (0.07-0.14 Hz) are noninvasive measures of cardiac baroreflex function derived by spontaneous sequence and cross-spectral analysis. To demonstrate the difference between these baroreflex estimates, 14 patients received etomidate (0.3 mg/kg bolus and 0.9 mg/kg/h infusion), lidocaine (60 mg), and vecuronium (0.1 mg/kg) by intravenous injection. The authors found that spontaneous baroreflex sensitivity and high-frequency gain were decreased (p <0.05) after etomidate anesthesia, whereas mid-frequency gain was maintained. Spontaneous baroreflex sensitivity, high-frequency gain, and mid-frequency gain, although compared simultaneously, did not change in a parallel manner. In another 5 patients, who received normal saline only, measures were unchanged. The authors conclude that spontaneous baroreflex sensitivity, high-frequency gain, and mid-frequency gain are not interchangeable. Experimental results on baroreflex control depend on the parameter selected.

Adult↗

PubMed2000

Thoracoscopic plication of diaphragmatic eventration using endostaplers.

Unilateral diaphragmatic eventration and paralysis require plication in cases of progressive dyspnea on exertion and recurrent respiratory infection. The patient, a 40-year-old woman, who had complained of worsening dyspnea on exertion and elevation of the left diaphragm on chest radiographs for 4 years, underwent plication by thoracoscopy with knifeless endostaplers. Improvements in pulmonary functions and dyspnea on exertion have been maintained for 14 months.

Adult↗

PubMed2000

Length-dependent effects of osmotic compression on skinned rabbit psoas muscle fibers.

The goal of this study was to characterize the interrelationship between sarcomere length and interfilament spacing in the control of Ca2+ sensitivity in skinned rabbit psoas muscle fibers. Measurements were made at sarcomere lengths 2.0, 2.7 and 3.4 microm. At 2.7 microm the fiber width was reduced by 17% relative to that at 2.0 microm and the pCa50 for force development was increased by approximately 0.3 pCa units. In the presence of 5% Dextran T-500 the fiber width at sarcomere length 2.0 microm was also decreased by 17% and the Ca2+ sensitivity was increased to the same value as at 2.7 microm. In contrast, at sarcomere length 2.7 microm the addition of as much as 10% Dextran T-500 had no effect on Ca2+ sensitivity. At sarcomere length 3.4 microm there was an additional 7% compression and the Ca2+ sensitivity was increased slightly (approximately 0.1 pCa units) relative to that at 2.7 microm. However at 3.4 microm the addition of 5% Dextran T-500 caused the Ca2+ sensitivity to decrease to the level seen at 2.0 microm. Given that the skinning process causes a swelling of the filament lattice it is evident that the relationship between sarcomere length and Ca2+ sensitivity observed in skinned fibers may not always be applicable to intact fibers. These data are consistent with measurements of Ca2+ in intact fibers which indicate that there might be a decline in Ca2+ sensitivity at long sarcomere lengths.

Animals↗