Biomedical subjects
Publications and source records attributed to Q Ni.
A novel core-shell gold colloid-silk fibroin (SF) bioconjugate was prepared by the protein in situ redox technique at room temperature, in which the tyrosine (Tyr) residue of the SF, having strong electron donating properties, in situ reduced Au(III) ions to Au colloids showing a stable and highly monodispersed nature.
OBJECTIVE: To further elucidate the clinical feature, treatment and prognosis of pancreatic cancer in elderly patients. METHODS: Data of 180 elderly patients with pancreatic cancer operated upon during 1990-2000 were analyzed. Postoperative complications and 30-day mortality rates were recorded among the 46 cases subjective to Whipple procedure, including 22 cases undergoing regional pancreatoduodenectomy after intervention therapy. 78 patients received palliative surgery and 50 patients received laparotomy. Follow-up was made for 6 months to 10 years. RESULTS: All the patients were operated upon successfully. 48 patients underwent radical pancreatectomy with a mortality rate of 6.2 per cent, a complication rate of 20.8 per cent, and a mean survival period of 26 months. The 78 cases undergoing palliative surgery survived for 6 months on average. 54 patients undergoing laparotomy only survived for 3 months on average. CONCLUSION: Aggressive surgical management helps prolong the survival period and improve the life quality of elderly patients with pancreatic cancer.
OBJECTIVE: To investigate the apoptosis of pancreatic acinar and the expression of TNF-alpha mRNA, IL-10 mRNA in pancreatic tissue of rats with acute pancreatitis. METHODS: The model of acute edematous pancreatitis(AEP) was established in 20 rats and that of acute necrotizing pancreatits(ANP) in another 20 by injection of sodium taurocholate into the pancreatic duct. Another 10 normal rats were used as controls. At 12 hours after the induction of pancreatitis, 10 rats in each group were sacrificed. Serum and pancreatic TNF-alpha and IL-10 levels were measured. The expression of TNF-alpha and IL-10 mRNA in pancreas was detected and the apoptotic rate of pancreatic acinar determined. RESULTS: The apoptotic rate of pancreatic acinar in normal, AEP and ANP groups was 2.98%, 17.29% and 8.39%, respectively. TNF-alpha and IL-10 levels increased after the induction of acute pancreatitis. The level of TNF-alpha was lower while that of IL-10 higher in AEP group than in ANP group. Transcription level of TNF-alpha mRNA in ANP group and that of IL-10 mRNA in AEP group were upregulated. CONCLUSIONS: The transcription levels of TNF-alpha and IL-10 mRNA in pancreatic tissue of rats with acute pancreatitis are positively correlated with their levels in serum and pancreas, suggesting that the pancreas is the organ to release cytokines. The apoptotic rate of pancreatic acinar is negatively correlated with the severity of disease and apoptosis may be a benign response to pancreatic injury.
OBJECTIVE: To determine the role of systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS), and evaluate the progress from SIRS to MODS and the therapeutic strategies for acute necrotizing pancreatitis (ANP). METHODS: Rat ANP models were made by retrograde injection of 3.5% sodium taurocholate 2.5 ml/kg into the pancreatic duct. Serum interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF alpha), amylase, endotoxin, and albumin were examined. The morphology and pathology of the pancreas, liver, lung, kidney and heart after ANP were observed. Finally, TNF alpha mRNA in the liver, lung, kidney and heart after ANP were observed by reverse transcriptase-polymerase chain reactions, and the efficiency of somatostatin and growth hormone were also observed in this experiment. RESULTS: ANP led to remarkable elevation of the inflammatory mediators which were positively correlated with the development of ANP and MODS. Somatostatin and growth hormone inhibited inflammatory mediators and TNF alpha mRNA overexpressions, reduced the risk of MODS, corrected hypoalbuminemia, reversed negative nitrogen balance, and controlled the reduction of cell groups with functions and reasonably intervened SIRS caused by ANP. CONCLUSION: TNF alpha mRNA plays an important role in ANP progression. The amelioration of ANP by combination treatment with somatostatin and growth hormone leads to the reduction of complications and marked increase in survival.
The mechanisms by which prolonged exposure to morphine leads to tolerance are not fully understood. We investigated the effects of etorphine (ET) on [(35)S]guanosine 5'-(-thio)-triphosphate ([(35)S]GTP-gamma-S) binding in brains of rats made tolerant to morphine via the implantation of morphine (or placebo) pellets. Binding surface analysis was used to characterize the interactions of ET, Gpp(Np)H and GTP-gamma-S with sites labeled by [(35)S]GTP-gamma-S. Data sets were fitted to one- and two-site binding models using the nonlinear least squares curve fitting program MLAB-PC (Civilized Software, Bethesda, MD, USA). Two binding sites were readily resolved. Chronic morphine significantly increased the B(max) and K(d) of the high affinity binding site. ET stimulated [(35)S]GTP-gamma-S binding in placebo membranes via an increase in the B(max) of the high affinity binding site. In contrast, ET stimulated [(35)S]GTP-gamma-S in chronic morphine membranes via a large decrease in the K(d) of the high affinity site. These results suggest that chronic morphine treatment alters the mechanism by which ET stimulates [(35)S]GTP-gamma-S binding to G-proteins. Since proper G-protein/receptor coupling increases [(35)S]GTP-gamma-S binding via an increase in B(max) values, these results suggest that opioid receptors in chronic morphine membranes are not normally coupled to G-proteins. These findings corroborate earlier studies that reported changes in G-protein function in morphine tolerant animals.
The long-term goal of electrocardiography is to relate electric potentials on the body surface with activities in the heart. Many previously reported studies have focused on direct links between heart and body surface potentials. The goals of this study were first to validate computational methods of determining volume potentials and currents with high-resolution experimental measurements and then to use interactive visualization of thoracic currents to understand features of the electrocardiographic fields from measured cardiac sources. We developed both simulation and experimental studies based on a realistic shaped torso phantom containing an isolated, perfused dog heart. Interventions included atrial pacing, single pacing and simultaneously pacing at multiple locations on the ventricles. Simulated torso volume potentials closely matched measured potentials in the torso-tank preparation (mean correlation coefficients of 0.95). Simulation further provided a means of estimating the current field in the torso from the computed torso volume potentials and the local geometric and conductive properties of the medium. Applying these techniques to the torso electric fields under a variety of pacing conditions, we have further demonstrated that thoracic current can provide many insights into the relationship between heart surface potential and body surface potentials. Specifically, we have shown that geometric factors including cardiac source configuration and location play an important role in determining to what extent electric activity in the heart is directly visible on the body surface electrocardiogram. The computation and visualization toolkit we developed in this study to explore current fields associated with cardiac events may provide new insights into electrocardiology.
Previous studies have examined the influence of body position, respiration, and habitus on body surface potentials. However, the authors could only estimate the sources of the effects they documented. Among the proposed origin of changes in body surface potentials from those studies were the position of the heart, alterations in autonomic tone, differences in ventricular blood volume, and variations in torso resistivity. The goal of this study was to investigate specifically the role of geometric factors in altering body surface potentials and the electrocardiogram. For this, we used experiments with an isolated, perfused dog heart suspended in a realistically shaped electrolytic torso tank. The experimental preparation allowed us to measure epicardial and tank surface potentials simultaneously, and then reconstruct the geometry of both surfaces. Our results mimicked some of the features described by previous investigators. However, our results also showed differences that included considerably larger changes in the peak QRS and T-wave amplitudes with heart movement than those reported in human studies. We detected smaller values of root-mean-squared variability from heart movements than those reported in a human study comparing body surface potentials during change in inspiration and body position. There was better agreement with relative variability, which in these studies ranged from 0.11 to 0.42, agreeing well with an estimate from human studies of 0.40. Our results suggest that the isolated heart/torso tank preparation is a valuable tool for investigating the effects of geometric variation. Furthermore, the geometric position of the heart appears to be a large source of variation in body surface potentials. The size of these variations easily exceeded thresholds used to distinguish pathologic conditions and thus such variations could have important implications on the interpretation of the standard electrocardiogram.
The binding of the methylanthraniloyl derivatives of ATP (mant-ATP), ADP (mant-ADP), 2'deoxyATP (mant-2'deoxyATP), and 3'deoxyATP (mant-3'deoxyATP) to the catalytic subunit of protein kinase A was studied to gain insights into the mechanism of nucleotide binding. The binding of the mant nucleotides leads to a large increase in fluorescence energy transfer at 440 nm, allowing direct measurements of nucleotide affinity. The dissociation constant of mant-ADP is identical to that for ADP, while that for mant-ATP is approximately threefold higher than that for ATP. The dissociation constant for mant-3'deoxyATP is approximately fivefold higher than that for 3'deoxyATP while derivatization of 2'deoxyATP does not affect affinity. The time-dependent binding of mant-ATP, mant-2'deoxyATP, and mant-ADP, measured using stopped-flow fluorescence spectroscopy, is best fit to three exponentials. The fast phase is ligand dependent, while the two slower phases are ligand independent. The slower phases are similar but not identical in rate, and have opposite fluorescence amplitudes. Both isomers of mant-ATP are equivalent substrates, as judged by reversed-phase chromatography, although the rate of phosphorylation is approximately 20-fold lower than the natural nucleotide. The kinetic data are consistent with a three-step binding mechanism in which initial association of the nucleotide derivatives produces a highly fluorescent complex. Either one or two conformational changes can occur after the formation of this binary species, but one of the isomerized forms must have low fluorescence compared to the initial binary complex. These data soundly attest to the structural plasticity within the kinase core that may be essential for catalysis. Overall, the mant nucleotides present a useful reporter system for gauging these conformational changes in light of the prevailing three-dimensional models for the enzyme.
OBJECTIVE: To evaluate the feasibility and effectivity of "3 steps procedure" in the treatment of large pancreatic head cancer. METHODS: The "3 steps procedure" consisted of decompression of jaundice by simple cholecystotomy, intervenient (intra-arterial) chemotherapy (5-FU 1 approximately 1.5 g, mitomycin 8 approximately 14 mg, cisplatin 40 approximately 60 mg and octreatide 1 mu intravenously as near the superior and inferior pancreatic-duodenal arteries as possible), and then the reasonable regional pancreatic-duodenectomy. RESULTS: All 16 tumors were radically resected. Conventional and regional pancreatic-duodenectomy was done in 7 and 9 patients, respectively; of the later group, artificial prosthesis for portal vein bridge was done in 3 patients, end-to-end anastomosis in 4 and repair after partial resection of invaded vessel wall in 2. CONCLUSION: The "3 steps procedure" is feasible and effective in the treatment of large pancreatic head cancer.
OBJECTIVE: To observe the effect of Tangweikang capsule (TWKC) in treating diabetic nephropathy (DN). METHODS: The 119 patients enrolled were divided into 2 groups, 78 patients in the TWKC group treated with TWKC and 41 patients in the control group treated with Captopril. The changes of symptom score, urinary microprotein series (urinary albumin excretion rate, Tamm-horsfall protein and beta 2-microglobulin), blood glucose, kidney function, blood lipid, angiotensin I (A I) and II (A II), atrial natriuretic polypeptide (ANP), thromboxane B2(TXB2), 6-keto-prostaglandin F1 alpha, endothelin 1 (ET-1) and collagen IV in patients after treatment were observed. RESULTS: The total effective rate in the TWKC group was 84.62%, which was superior to that in the control group (70.73%, P < 0.05). TWKC also showed better effects in improving clinical symptoms, lowering blood glucose, urinary microprotein series, blood lipid, A I, A II, ANP, ET-1 and collagen IV, ameliorating kidney function, and adjusting dynamic equilibrium of thromboxane-prostacyclin system, as compared with the control group (P < 0.05 or P < 0.01). CONCLUSION: TWKC could lower the levels of blood glucose and lipid, improve the glucose and lipid metabolism, regulate the microcirculation, ameliorate the degree of kidney damage, therefore, it showed a better effect in treating diabetic nephropathy.
We utilized the [(35)S]-GTP-gamma-S functional binding assay to determine the selectivity of opioid receptor agonists in guinea pig caudate membranes. The study focused on two opioid agonists used for treating opioid-dependent patients: methadone and buprenorphine. Selective antagonists were used to generate agonist-selective conditions: TIPP + nor-BNI to measure mu receptors, CTAP + nor-BNI to measure gamma receptors and TIPP + CTAP to measure kappa receptors. The assay was first validated with opioid agonists of known subtype specificity (DAMGO for mu, SNC80 for delta, and U69, 593 for kappa receptors). Methadone-stimulated [(35)S]-GTP-gamma-S binding was mu-specific and less potent and efficacious than etorphine (K(d) = 1,537 nM vs. K(d) = 7.8 nM). Buprenorphine failed to stimulate [(35)S]-GTP-gamma-S binding but inhibited agonist-stimulated [(35)S]-GTP-gamma-S binding. The antagonist-K(i) values (nM) of buprenorphine at mu, delta, and kappa receptors were 0.088 nM, 1.15 nM, and 0.072 nM, respectively. The antagonist-K(i) values (nM) of naloxone at mu, delta, and kappa receptors were 1.39 nM, 25.0 nM, and 11.4 nM, respectively. Autoradiographic studies showed that buprenorphine failed to stimulate [(35)S]-GTP-gamma-S binding in caudate-level rat brain sections but blocked DAMGO-stimulated [(35)S]-GTP-gamma-S binding. In cells expressing the cloned rat mu receptor, buprenorphine was a partial agonist and potent mu antagonist. Administration of buprenorphine to rats produced a long-lasting (>24 h) decrease in mu and kappa2 receptor binding and attenuated mu-stimulated [(35)S]-GTP-gamma-S binding. Viewed collectively, these data indicate that, in this assay system, buprenorphine is a potent mu and gamma receptor antagonist. The clinical implications remain to be elucidated. Synapse 34:83-94, 1999. Published 1999 Wiley-Liss, Inc.
Multielectrode catheters provide a percutaneous means of recording activation near the epicardium but only for a relatively small number of sites that are restricted to the major coronary vessels. We have applied a statistical signal processing technique to estimate the value of activation time over the entire epicardium (490 sites) from leadsets consisting of 4 to 40 sites aligned with major branches of the coronary veins. We tested this method using data from high-resolution epicardial mapping from six dog hearts and 153 activation sequences. A study including data from both normal and infarcted dog hearts yielded estimates of activation time, with mean correlation coefficients ranging from 0.97 to 0.84 and achieved localization of earliest site of activation to within 3 to 15 mm, depending on training parameters and leadset. These results suggest that with 10 to 15 catheter-mounted electrodes, it may be possible to reconstruct epicardial activation maps from percutaneous recordings.
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OBJECTIVE: To investigate the practicability of proglumide to treat gastric cancer. METHODS: MKN45 gastric cancer cell line was cultured and the effects on gastrin and gastrin receptor antagonist proglumide proliferative rate, cell dynamic cycle distribution and the concentration of cAMP in the cells were observed in vitro. RESULTS: Gastrin promoted the proliferation of MKN45 cells and shifted cells from phase G(0)/G(1) to phase S, G(2)/M as well as increased intracellular cAMP, while proglumide blocked these effects. CONCLUSIONS: Gastrin induces the proliferation and synthesis of DNA by its receptor. Proglumide may provide a new approach of non-cytotoxic treatment of gastric cancer.
Quantitative binding studies resolved two high-affinity [3H][D-Ala2,D-Leu5]enkephalin binding sites in rat brain membranes depleted of mu binding sites by pretreatment with the irreversible agent BIT. The two binding sites had lower (delta ncx-2, Ki = 96.6 nM) and higher (delta ncx-1, Ki = 1.55 nM) affinity for DPDPE. The ligand-selectivity profile of the delta ncx-1 site was that of a classic delta binding site. The ligand-selectivity profile of the delta ncx-2 site was neither mu- or delta-like. The Ki values of selected agents for the delta ncx-2 site were: [pCl]DPDPE (3.9 nM), DPLPE (140 nM), and DAMGO (2.6 nM). Under these assay conditions, [3H][D-Ala2,D-Leu5]enkephalin binding to the cells expressing the cloned mu receptor is very low and pretreatment of cell membranes with BIT almost completely inhibits [3H]DAMGO and [3H][D-Ala2,D-Leu5]enkephalin binding. Intracerebroventricular administration of antisense DNA to the cloned delta receptor selectively decreased [3H][D-Ala2,D-Leu5]enkephalin binding to the delta ncx-1 site. Administration of buprenorphine to rats 24 h prior to preparation of membranes differentially affected mu, delta ncx-1, and delta ncx-2 binding sites. Viewed collectively, these studies have identified a novel non-mu- non-delta-like binding site in rat brain.
OBJECTIVE: To study the role of somastostatin and growth hormone in preventing liver damage due to ANP. METHODS: The roles of inflammatory mediators (Endotoxin, Amylase, TNF alpha) were investigated in ANP model by retrograde injection of 3.5% sodium taurocholate 2.5 ml/kg into the pancreatic duct, and TNF alpha mRNA in the liver after ANP was observed by reverse transcriptase-polymerase chain reaction. Besides, the effects of somastostain and growth hormone were also observed. RESULTS: ANP caused remarkable elevation of those inflammatory mediators, being positively correlated with the development of pancreas and liver damage. Somastostain and growth hormone inhibited the inflammatory mediates and TNF alpha mRNA overexpression and reduced the damage to the pancreas and liver. CONCLUSIONS: TNF alpha plays an important role in ANP progression, and somastostatin and growth hormone may prevent the development and progression of liver damage due to ANP.
OBJECTIVE: To observe the ameliorative effect of Zishen Decoction (ZSD) on chronic uric acid nephrosis (CUAN). METHODS: The 72 CUAN patients were divided into 2 groups: The group with ZSD treatment, the dose of which was 400 ml/d and group with zyloric as the control, the dose of which was 200 mg/d. The treatment lasted for 8 weeks. RESULTS: The general effective rate of the ZSD group was 92.86%; and that of the control group Was 66.67%. There was significant difference between the two groups (P < 0.01). ZSD treatment reduced the levels of blood uric acid, serum creatinine and blood urea nitrogen and the levels of albumin, beta 2-microglobulin and the activity of N-acetyl-D-glucosaminidase in CUAN (P < 0.01). The levels of triglyceride and total cholesterol decreased and the levels of high density lipoprotein cholesterol increased in the serum of ZSD treated CUAN (P < 0.01). CONCLUSIONS: ZSD exerted obviously ameliorative effect on renal function in CUAN.
AIM: To establish a method for continuously cultivating a large number of P. falciparum gametocytes in vitro using carbon dioxide incubator. METHODS: The number of gametocytes produced in experimental and control groups was compared after the addition of various concentrations of NaHCO3 to the culture medium. RESULTS: The gametocytes began to rise on day 5 of cultivation and reached a peak on day 11-13. The peak gametocyte loads were 1.9% +/- 0.6% and 1.3% +/- 0.4% (P < 0.05) in experimental and control group, respectively, indicating that the complete medium with 30 mmol/L sodium bicarbonate was beneficial to gametogenesis. The numbers of stages I-V gametocytes rose to a peak on d5, d7, d11, d13 and d15, respectively. On day 15 the percentage of stage V gametocytes was 7.1%-52.6% with an average of 24.3%. The ratio of macrogametocyte to microgametocyte was 12.8:1. The parasites were able to produce high gametocytaemia up to 24th subculture after thawing. Laboratory reared Anopheles stephensi fed through membrane on blood infected with P. falciparum were dissected, no oocyst was found in the midgut. CONCLUSION: A culture system which could consistently and stably produce a large number of gametocytes of P. falciparum was established.