Biomedical subjects

W L Peng

Publications and source records attributed to W L Peng.

9 recordsLinked to original sources

PubMed2001

[Mitochondrial permeability transition pore regulates the apoptosis in MGC-803 induced by the extract of glycyrrhiza uralensis Fisch].

In our previous studies, we have discovered that the extract of glycyrrhiza uralensis Fisch (EGUF) can induce obvious apoptosis in gastric cancer cell Line MGC-803. Here, further investigation was carried on about the time-lapse changes of mitochondria transmembrane potential, intracellular free calcium ions, DNA electrophoresis, plasma membrane permeability and chromatin condensation during the apoptotic process of MGC-803 induced by EGUF and the influences of MPT-specific inhibitor Cyclosporin A(CsA) on these changes. Enhancement of plasma membrane permeability with PI staining, increase of intracellular free calcium ion and decrease of mitochondria transmembrane potential are early events in apoptotic cascades, prior to the appearances of apoptotic peak, chromatin condensation and DNA ladder. CsA significantly inhibited enhancement of plasma membrane permeability, change of intracellular free calcium ions and decrease of mitochondria transmembrane potential, also greatly delayed the progress of apoptosis. Thus, our results suggest that calcium and CsA-sensitive MPT is involved in the apoptosis of MGC-803 induced by EGUF.

Apoptosis↗

PubMed1997

Metabolic characteristics and enflurane defluorination of cytochrome P450-dependent monooxygenases in human hepatocellular carcinoma.

BACKGROUND: Xenobiotic metabolism and defluorination capacity of microsomal monooxygenases were investigated in vitro through the surgical specimens of liver resected from patients with hepatocellular carcinoma and patients of extrahepatic pathology as control. METHODS: In microsomes of hepatocellular carcinoma tissues, the activities of cytochrome P450-dependent monooxygenase isoenzymes 1A1, 2B1, and 2E1 were evaluated in vitro by reacting with the specific marker substrates benzo(a)pyrene, benzphetamine and aniline, respectively, in the generating incubation system. The distant normal liver tissues and tissues from control patients with extrahepatic lesion were also investigated for comparison. The ability of enflurane defluorination was assessed by Orion combined for detection of free fluoride ion production. RESULTS: Concentrations of P450 total content, cytochrome b5, and NADPH-cytochrome c reductase showed parallel and marked reduction in tumor tissues when compared with its distant normal regions or normal livers. The monooxygenase functions displayed significant decreases within the tumor tissues as benzo(a)pyrene hydroxylation > or = benzphetamine demethylation > aniline hydroxylation in magnitude. Defluorination of enflurane also markedly decreased in tumor tissues comparing with normal livers. CONCLUSIONS: These marked reductions in the compositions and in vitro metabolic activities, including defluorination of anesthetics, in the cytochrome P450-dependent monooxygenases within the tumor tissues characterize the unique pattern of xenobiotic metabolism in patients with hepatocellular carcinoma.

Aged↗

PubMed1994

[High-performance liquid chromatographic method for the determination of diclofenac in serum and its pharmacokinetics in healthy volunteers].

A sensitive and rapid high-performance liquid chromatographic method has been developed for the determination of diclofenac in human serum. The average recovery of diclofenac was 98.2% to 102.5%. The relative standard deviation was 1.29% to 4.52%. The calibration curve was linear in the range from 0.2 microgram/ml to 10.0 micrograms/ml with r = 0.9999. The detection limit of the method was 10 ng/ml. The serum drug concentration-time curve exhibited a 1-compartment open model and the mean T1/2 was 2.15 h.

Adult↗

PubMed1993

[Midazolam and Meperidine for colonoscopy].

We studied the sedative, analgesic and amnesic effects of intravenous midazolam and meperidine for colonoscopy, and also compared patient's satisfaction, changes of vital signs, safety and complications with intramuscular meperidine during the colonoscopy. Two hundred and ninety-nine patients undergoing physical check-up were randomized to receive intramuscular meperidine 50 mg and Hyoscine-N-Butylbromide (buscopan) 20 mg (Group IM-MB, n = 57) or intravenous midazolam 0.05 mg/kg, meperidine 1 mg/kg and buscopan 20 mg (Group IV-MMB, n = 242) before colonoscopy. All patients were closely observed and arterial oxygen saturations (SaO2) were monitored with pulse oximeter in Group IV-MMB. The demographic data of both groups were similar. There were significantly more severe pain responses (grimacing, moaning, shouting for pain, abdominal rigidity and body moving during colonoscopy) in Group IM-MB (51%) than in Group IV-MMB (13%) (p < 0.01). In immediate procedure recall after recovery from medications, 39% of Group IM-MB remembered severe pain during colonoscopy and only 3% of Group IV-MMB did (p < 0.01). 92% of Group IV-MMB who felt satisfactory with the medications were significantly higher than 21% in Group IM-MB (p < 0.01). Both groups significantly increased in heart rate after the injection of medications (p < 0.01). Group IM-MB increased 15 +/- 18% and Group IV-MMB 61 +/- 28% with significant difference between groups (p < 0.01). This might be caused by meperidine, buscopan, and relative hypovolemia of patients. There were significant decreases in SaO2 in Group IV-MMB, mean 4.5 +/- 1.7% (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

T lymphocyte changes in open heart surgery.

To investigate the effect of open heart surgery on T lymphocytes and their subpopulations, 20 patients, who had undergone moderate- to high-dose fentanyl anesthesia and a cardiopulmonary bypass (CPB), were studied using flow cytometry techniques and monoclonal antibodies during and after surgery. The ages of these patients ranged from four to 61 years with eight being male and 12 being female. The disease entity consisted of four with coronary, six with congenital and 10 with valvular heart disease. No cyanotic patients were included in this study. Peripheral blood samples were collected before anesthesia, immediately before the surgical incision, on the first postoperative day (POD1) and on the second postoperative day (POD2), respectively. We found no significant changes in the percentage of total T cells (T3), or helper (T4) and suppressor (T8) T cells during anesthesia before the surgical incision. On POD1, all T lymphocyte subset percentages decreased significantly when compared to pre-operative values (total T cells: 58.4 +/- 12.6 vs 24.4 +/- 8.4, helper T cells: 33.3 +/- 10.1 vs 15.4 +/- 6.3, suppressor T cells: 23.0 +/- 6.4 vs 10.0 +/- 4, all p less than 0.001) but returned to preoperative levels on POD2. Throughout the study period, there were no significant changes in the T helper cell to T suppressor cell ratio. In spite of the transient decrease in T lymphocytes and their subpopulations, no clinical evidence of infection was noted in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Can cancer pain attenuate the physical dependence on chronic long-term morphine treatment?

This prospective and comparative study was designed to determine the role of cancer pain and attitudes towards morphine in attenuating the intensity and duration of physical dependence following chronic morphine treatment. Morphine was administered via a stepwise ladder approach in order of oral, spinal and intravenous routes depending on the adequacy of analgesia. On-demand titration of a dose, either upward or downward, was liberal and unlimited. Withdrawal strategy was evaluated and initiated either by patients (PI group) or their families (FI group). The manifestation of physical dependence on morphine was compared between patients who successfully withdrew (total withdrawal), and patients who failed to withdraw (episodic withdrawal), from morphine for a period of more than two weeks. Eighty-eight out of 627 patients (14.1%) were excluded from our protocol; 75% of these exclusions were due to objections toward morphine as the major form of analgesic. Drop-out due to poorly tolerated side effects was relatively rare (18.2%). Fifty-four (10.0%) achieved total withdrawal and 212 (39.3%) experienced episodic withdrawal. Non-pain-related abstinence symptoms were highly prevalent but were tolerable for both groups. Pain-related symptoms were more exaggerated during episodic withdrawal. Intolerable pain, rather than physical dependence, contributed to the failure to withdraw from morphine. Among a total of 539, addiction was found in only one patient (0.18%) who began drug use long before entering our protocol. Attitudes towards morphine affect the acceptance of treatment and hasten the withdrawal strategy. Families were more anxious about morphine than the patients themselves which led to more aggressive, but less tolerable, withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Hyperamylasemia following cardiopulmonary bypass.

In order to study the occurrence of postbypass hyperamylasemia, 75 patients undergoing cardiopulmonary bypass (CPB) were studied from March 1989 to January 1990. There were 49 males and 26 females. Among them, 27 had congenital heart disease, 30 had valvular disease, and 18 had coronary artery disease. There were 27 patients with at least one elevated serum amylase sample after operation. Thus, the overall incidence of hyperamylasemia was 36%. As compared with the preoperative data (1.3%), there was a statistically significant difference in the occurrence of hyperamylasemia (p less than 0.05). Three patients had overt clinical pancreatitis postoperatively. There was no positive correlation between the serum amylase level and the occurrence of pancreatitis (p greater than 0.05). Forty-two cases had a significant elevation of the amylase creatinine clearance ratio (ACCR) after CPB. However, there was no significant difference between the groups with pulsatile and nonpulsatile CPB (p greater than 0.05). Three patients (4%) died in our series. The causes of death were heart failure in two and fulminant pancreatitis associated with low cardiac output in one. Although our experience in dealing with pancreatitis improved survival, mortality was still high (33.3%) in our series. Nevertheless, there was no apparent correlation between mortality and postbypass hyperamylasemia (p greater than 0.05). Logistic regression analysis was used to analyze the risk factors of the occurrence of hyperamylasemia, and the analysis revealed that patients with coronary artery disease were susceptible to postbypass hyperamylasemia. Our studies indicate that the use of total serum amylase or ACCR to monitor for the occurrence of pancreatitis in postbypass patients is inadequate.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗

PubMed1992

[Patient-controlled intravenous versus epidural analgesia after major joint replacement].

The analgesic efficacy, side effects, and satisfaction of patient-controlled analgesia (PCA) with intravenous and epidural morphine for postoperative pain were evaluated in this study. Twenty patients undergoing major joint replacement surgery were randomly allocated to intravenous PCA (IPCA) group or epidural PCA (EPCA) group. All patients had a standardized balanced anesthesia, and an epidural catheter was introduced after the operation in EPCA group. Postoperative pain relief was evaluated with verbal pain scale. The result showed that pain intensity and pain relief were similar in either group without significant difference (p greater than 0.05). Morphine consumption in IPCA group was 1.72 +/- 0.30 mg/h in the postoperative 0 - 12 h and 1.14 +/- 0.44 mg/h in 12 - 24 h. In EPCA group, relatively low doses of morphine were used, i.e., 0.20 +/- 0.07 mg/h in the postoperative 0 - 12 h and 0.17 +/- 0.07 mg/h in 12 - 24 h. Both groups showed an "incomplete" but satisfactory analgesia with relatively low doses of morphine. The "equianalgesic dose ratio" of IPCA to EPCA with morphine was approximately 8.5:1. Sedation was minimal in both groups. No respiratory depression developed in all patients. Nausea and vomiting were the most prominent side effects which might limit the usefulness of PCA. The incidence was 5 out of 10 patients in IPCA group and 4 out of 10 patients in EPCA group, despite under the treatment of droperidol (15 micrograms/kg, iv, prn) for most of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Analysis of T cell receptor Vbeta gene usage during the course of disease in patients with chronic hepatitis B.

The T cell receptor (TCR) is a heterodimeric molecule expressed on the surface of T cells and recognizes foreign peptides presented by the major histocompatibility complex on the surface of antigen-presenting cells or virus-infected cells. Analysis of TCR usage by T cells which recognize hepatitis B virus (HBV) provides further insight into the participation of T cell populations during the course of disease. In this study, we examined the T-cell-proliferative response and the TCR Vbeta gene usage of peripheral blood mononuclear cells in 3 patients with clinical evidence typical of chronic hepatitis B. All 3 patients had significant T-cell proliferative responses against HBV core antigen (HBcAg) during the remission stage, while no responses were detected during the acute exacerbation stage. In addition, the TCR Vbeta7 gene was utilized more frequently in T cells recognizing HBcAg during remission, while TCR Vbeta1 and Vbeta2 were utilized at a higher percentage during acute exacerbation. On the contrary, the T cell proliferative response against HBV surface antigen was undetectable and no specific Vbeta gene was utilized more frequently by all 3 patients, regardless of disease state. Our longitudinal studies, although based on a small sample of patients, demonstrate that the population of HBcAg-activated T cells alters during the course of disease in chronic hepatitis B patients.

Genes, Immunoglobulin↗