Gene/Protein Disease Symptom Drug Enzyme Compound
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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The time course of iron overload of the pancreas in hypotransferrinaemic mice maintained on a standard rodent diet was compared with biochemical and histological markers of tissue damage. 2. Pancreatic iron levels increased linearly from weaning till 9 months of age [73.3 nmol/mg of tissue (SEM 9.9; n = 5) compared with 0.9 nmol/mg of tissue (SEM 0.1; n = 4) in age-matched controls] then decreased linearly till at least 18 months of age. 3. Investigation of tissue distribution of newly absorbed radioiron suggested that significant redistribution of iron from liver to pancreas (rather than direct dietary iron sources) must be invoked to explain the rate of pancreatic iron loading in hypotransferrinaemic mice. 4. Pancreatic epithelial cells first showed altered morphology at 9 months of age. At 12 months of age, the pancreatic epithelium had developed a micronodular appearance, with large numbers of acini replaced by atrophic, degenerated acinar cells. Increased collagen fibre deposition was evident by trichrome staining and by electron microscopy. Biochemical markers of pancreatitis (serum lipase, tissue pancreatitis-associated protein mRNA) were elevated before 9 months of age, whereas the levels of pancreatic amylase mRNA declined from 9 months of age. 5. The data suggest that iron loading of hypotransferrinaemic mouse pancreas proceeds up to a threshold level at 9 months of age followed by a progressive atrophy of secretory epithelium. The hypotransferrinaemic mouse pancreas is a useful model system for investigation of parenchymal cell damage by iron.
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PMID:Time-course of iron overload and biochemical, histopathological and ultrastructural evidence of pancreatic damage in hypotransferrinaemic mice. 948 91

It was recently demonstrated in experimental models that, after pancreatic outflow obstruction, serum amylase levels first increase and then progressively decline regardless of whether the obstruction was maintained or relieved. Furthermore, early decompression of the ductal biliary system may prevent the progression of the disease. This finding prompted us to look for a similar pattern in patients with obstructive acute pancreatitis due to biliary stones. Forty-two patients with biliary acute pancreatitis were prospectively studied. Twenty-one patients underwent urgent endoscopic sphincterotomy (ES), and 21 received conservative medical treatment (CMT). The two groups were comparable for sex, age, onset of pain, and severity. Serum amylase and lipase were determined in all patients on admission and 24 h later. The percentage variation of serum amylase and lipase was calculated considering, for each patient, the concentrations of the two enzymes assayed on admission and 24 h later. On admission, all patients had elevated serum concentrations of amylase (mean +/- SEM: ES, 2,560+/-473 U/L; CMT, 1,783+/-481 U/L) and lipase (ES, 3,037+/-574 U/L; CMT, 3,179+/-724 U/L). The serum amylase variation (mean +/- SEM) was -65.6+/-5.5% in the ES and -47.2.1+/-8.1% in the CMT patients. The serum lipase variation was -59.1+/-7.7 and -33.1+/-18% in the same groups, respectively. These differences were not statistically significant. Acute pancreatitis worsened in one patient in the ES group and in seven in the CMT group; this difference was statistically significant (p < 0.02). The mean length of hospitalization was 8.9 days in the ES group and 19.7 days in the CMT group (p < 0.001). Serum pancreatic enzymes determination is not useful to evaluate the results of the early decompression of biliary duct in human acute pancreatitis. Indeed, early endoscopic sphincterotomy may result in a substantial improvement in the outcome of biliary acute pancreatitis.
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PMID:Effects of early ductal decompression in human biliary acute pancreatitis. 951 Jan 40

Hypertriglyceridemia is commonly associated with triglyceride (TG) enrichment of high density lipoprotein (HDL) and reduction in HDL cholesterol and apolipoprotein A-I levels. We have recently reported that lipolytic modification of TG-rich HDL, which reduces particle size, enhances its clearance from the circulation. In the present study, we examined the role of particle size and lipid composition in determining the metabolic clearance of human HDL, in the absence of substantial in vivo modification of the particle by hepatic lipase. The rabbit, which has a very low hepatic lipase activity, was used for this purpose. Plasma fractions d < 1.21 g/ml were first isolated by ultracentrifugation from fasting humans with normal (NTG, n=6, mean plasma TG concentration=1.26+/-0.21 (SEM) mmol/l) or elevated plasma TG levels (HTG, n=5, TG=4.49+/-0.65 mmol/l). Small and large HDL particles were separated by gel filtration chromatography and were labeled with either 125I or (131)I. Large HDL were cleared more rapidly than small HDL in 10 out of 11 studies (P=0.006). There was, however, no difference in the fractional catabolic rate (FCR) of large HDL isolated from NTG versus from HTG subjects or in the FCR of small HDL from NTG versus HTG individuals. There was also no correlation between the TG content of HDL and its FCR. In summary, large, lipid-rich human high density lipoproteins (HDL) are cleared more rapidly than small human HDL in rabbits. These results, combined with our previous observation, also support the hypothesis that triglyceride enrichment of HDL, in the absence of substantial lipolytic modification, is not sufficient to enhance its clearance from the circulation.
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PMID:Analysis of particle size and lipid composition as determinants of the metabolic clearance of human high density lipoproteins in a rabbit model. 964 47

We studied whether gastrointestinal transit was disturbed during acute pancreatitis and attempted to identify which mechanisms might be involved in acute pancreatitis. Using a noninvasive hydrogen breath test to determine the orocecal transit time, 24 patients with the clinical diagnosis of acute pancreatitis were enrolled into the intestinal motility study. Orocecal transit time was measured twice in all patients: once at the acute stage and once at recovery. Blood was obtained to study amylase, lipase, C-reactive protein, erythrocyte sedimentation rate, and endothelin-1 and nitrate/nitrite levels. Orocecal transit times measured at the acute stage were significantly delayed compared with those at recovery (mean values +/- SEM, 130.0 +/- 9.0 vs 80.8 +/- 7.4 min, P < 0.001). Plasma endothelin-1 levels exhibited a positive correlation with orocecal transit times in the acute stage (r = 0.509, P = 0.011). The percentages of altered orocecal transit times also correlated with the percentages of altered plasma endothelin-1 levels (r = 0.751, P < 0.001). Plasma nitrate/nitrite levels significantly decreased at the acute stage compared with those at recovery (5.25 +/- 0.82 vs 10.20 +/- 1.24 microM, P < 0.05). We conclude that intestinal transit is delayed in patients with mild to moderate acute pancreatitis. Elevated plasma endothelin-1 levels in the acute stage may be one mechanism mediating intestinal dysmotility.
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PMID:Endothelin-1 is a candidate mediating intestinal dysmotility in patients with acute pancreatitis. 1023 98

Lipid delays gastric emptying, and aging is associated with changes in gastric motor function and transit. However, little is known about the effect of lipid on gastric emptying time in the elderly. To determine the effect of aging on lipid gastric emptying, we used electrical impedance tomography (EIT) to study gastric emptying of liquid meals with or without lipid in five young (23.0 +/- 0.6 years, mean +/- SEM) and six elderly (73.3 +/- 1.6 years) healthy male volunteers. These subjects drank 400 ml of non-lipid soup (triglycerides, 0 g) or lipid soup (triglycerides, 24.6g) in liquid test meals. To study the effect of lipolysis in the stomach, a liquid test meal containing 240mg of lipase in the lipid soup was also administered. Plasma cholecystokinin (CCK) concentration was measured by specific radioimmunoassay before and 30 min after the ingestion of a test meal. The gastric emptying time of the lipid soup was longer in the elderly than in the young subjects, and the time was significantly longer for lipid soup than for nonlipid soup (P < 0.05) in both the young and elderly subjects. Gastric emptying time for non-lipid soup was not significantly different between the elderly and young subjects. The administration of lipase shortened the gastric emptying time for lipid in both the elderly and the young subjects. Basal CCK concentration was significantly higher in the elderly than in the young subjects. However, there was no relationship between gastric emptying time and plasma CCK concentration after the ingestion of a test meal in the subjects overall. In conclusion, the delaying effect of lipid on gastric emptying is increased in the elderly, and the administration of lipase accelerates the emptying of lipid from the stomach.
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PMID:Effects of aging and gastric lipolysis on gastric emptying of lipid in liquid meal. 1045 75

Described is the first catalytic, asymmetric synthesis of (-)-podophyllotoxin and its C(2)-epimer, (-)-picropodophyllin. Asymmetry is achieved via the enzymatic desymmetrization of advanced meso diacetate 20, through PPL-mediated ester hydrolysis. A second key feature of the synthesis is the strategically late introduction of the highly oxygenated natural ring E through an arylcopper species. The successful implementation of this approach augers well for the introduction of other functionalized rings E for future SAR work. The synthesis begins from piperonal, which is fashioned into isobenzofuran (IBF) precursor 14 in three steps (bromination, acetalization, and halogen-metal exchange/hydroxymethylation). Interestingly, treatment of 14 with HOAc in commerical dimethyl maleate (contains 5% dimethyl fumarate) leads to a nearly equimolar mixture of fumarate- (15) and maleate-IBF Diels-Alder adducts (16 and 17), indicating that IBF 11 reacts about 15 times faster with dimethyl fumarate than with dimethyl maleate. With scrupulously pure dimethyl maleate a 2.8:1 endo:exo mixture of maleate DA adducts is still obtained. On the other hand, the desired meso diester 16 is obtained pure and in nearly quantitative yield by employing neat dimethyl acetylene dicarboxylate as the dienophile, followed by catalytic hydrogenation. Reduction (LiAlH(4)) of 16 provides meso diol 19, which is then treated with Ac(2)O, BzCl, and PhCH(2)COCl to provide the corresponding meso diesters, 20-22. Screening of these meso benzoxabicyclo[2.2.1]heptyl substrate candidates across a battery of acyl transfer enzymes leads to an optimized match of diacetate 20 with PPL. Even on 10-20 g scales, asymmetry is efficiently introduced here, yielding the key chiral intermediate, monoacetate 25 (66% isolated yield, 83% corrected yield, 95% ee). Protecting group manipulation and oxidation (Swern) provide aldehyde 27b, which undergoes efficient retro-Michael ring opening to produce dihydronaphthalene 30, in which the C(3) and C(4) stereocenters are properly set. Following several unsuccessful approaches to the intramolecular delivery of ring E (via Claisen rearrangement, Heck-type cyclization, or radical cyclization), a highly diastereoselective, intermolecular conjugate addition of the arylcopper reagent derived from (3,4,5-trimethoxy)phenylmagnesium bromide and CuCN to acyl oxazolidinone 50 was developed (85% yield, only the required alpha-stereochemistry at C(1) is observed). The conjugate addition product is converted to (-)-picropodophyllin in two steps (lactonization, SEM deprotection) or to (-)-podophyllotoxin, in three steps, through the introduction of a C(2)-epimerization step, under Kende conditions, prior to the final conjugate addition.
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PMID:Enzyme-assisted asymmetric total synthesis of (-)-podophyllotoxin and (-)-picropodophyllin. 1081 19

The aim of this study was to evaluate the effect of sc insulin (INS) compared with sulfonylurea (SUL) therapy, at the same level of blood glucose control, on the low density lipoprotein (LDL) subfraction profile in normolipidemic type 2 diabetic patients. Nine normolipidemic type 2 diabetic men (age, 56+/-3 yr; body mass index, 26.5+/-0.9 kg/m2; mean +/- SEM), after a 3-week wash-out period, were assigned to INS or SUL for 2 months in a randomized cross-over design. Doses were adjusted only during the first month and then were kept constant. At the end of the treatments, hemoglobin A1c, plasma lipids, LDL, and very low density lipoprotein (VLDL) subfraction profiles and plasma postheparin lipoprotein lipase and hepatic lipase (HL) activities were evaluated. Despite glucose control was similar at the end of both periods (hemoglobin A1c, 7.4+/-0.3% vs. 7.0+/-0.2%, INS vs. SUL), INS compared with SUL significantly reduced plasma triglyceride (0.9+/-0.1 vs. 1.1+/-0.1 mmol/L; P < 0.05). Although INS did not affect the LDL concentration, it induced a decrease in both the amount (59.0 = 9.8 vs. 76.1+/-16.8 mg/dL; P = NS) and the proportion (31.2+/-3.0% vs. 38.3+/-3.8%; P < 0.03) of small LDL. Moreover, the decrease in small LDL was positively related to the reduction of large VLDL (r = 0.67; P < 0.04) and HL (r = 0.69, P < 0.05) induced by insulin therapy. In conclusion, sc insulin therapy, independently of glucose control and even in the presence of quite low plasma triglyceride levels, is able to reduce small LDL particles in type 2 diabetic patients. This change is related to decreases in both HL activity and large VLDL particles.
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PMID:Effect of insulin and sulfonylurea therapy, at the same level of blood glucose control, on low density lipoprotein subfractions in type 2 diabetic patients. 1109 52

To increase the local concentration of tamoxifen in estrogen receptor (ER) positive breast cancer, we have developed and characterized nanoparticle formulation using poly(epsilon -caprolactone) (PCL). The nanoparticles were prepared by solvent displacement method using acetone-water system. Particle size analysis, scanning electron microscopy, zeta potential measurements, and differential scanning calorimetry (DSC) were used for nanoparticle characterization. Biodegradation studies were performed in the presence and absence of Pseudomonas lipase in phosphate-buffered saline (PBS, pH 7.4) at 37 degrees C. Tamoxifen loading over different concentrations was analyzed by high-performance liquid chromatography (HPLC) and the optimum loading concentration was determined. In vitro release studies were performed in 0.5% (w/v) sodium lauryl sulfate (SLS) containing PBS at 37 degrees C. Cellular uptake and distribution of fluorescent-labeled nanoparticles was examined in MCF-7 breast cancer cells. SEM micrographs and Coulter analysis showed nanoparticles with spherical shape and uniform size distribution (250-300 nm), respectively. Zeta potential analysis revealed a positive surface charge of +25 mV on the tamoxifen-loaded formulation. Being hydrophobic crystalline polyester, PCL did not degrade in PBS alone, but the degradation was enhanced by the presence of lipase. The maximum tamoxifen loading efficiency was 64%. Initial burst release of tamoxifen was observed, probably due to significant surface presence of the drug on the nanoparticles. A large fraction of the administered nanoparticle dose was taken up by MCF-7 cells through non-specific endocytosis. The nanoparticles were found in the perinuclear region after 1 h. Results of the study suggest that nanoparticle formulations of selective ER modulators, like tamoxifen, would provide increased therapeutic benefit by delivering the drug in the vicinity of the ER.
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PMID:Biodegradable poly(epsilon -caprolactone) nanoparticles for tumor-targeted delivery of tamoxifen. 1243 41

The lipase inhibitor, orlistat, is used in the treatment of obesity and reduces fat absorption by about 30%. However, the mean weight loss induced by orlistat is less than expected for the degree of fat malabsorption. It was hypothesised that lipase inhibition with orlistat attenuates the suppressive effects of oral fat on subsequent energy intake in normal-weight subjects. Fourteen healthy, lean subjects (nine males, five females; aged 25 +/- 1.3 years) were studied twice, in a double-blind fashion. The subjects received a high-fat yoghurt 'preload' (males 400 g (2562 kJ); females 300 g (1923 kJ)), containing orlistat (120 mg) on one study day (and no orlistat on the other 'control' day), 30 min before ad libitum access to food and drinks; energy intake was assessed during the following 8 h. Blood samples were taken at regular intervals for the measurement of plasma cholecystokinin (CCK). Each subject performed a 3 d faecal fat collection following each study. Energy intake during the day was greater following orlistat (10,220 (SEM 928) kJ) v. control (9405 (SEM 824) kJ) (P=0.02). On both days plasma CCK increased (P<0.05) after the preload. Plasma CCK 20 min following ingestion of the preload was less after orlistat (4.1 (SEM 0.9) pmol/l) v. control (5.3 (SEM 0.9) pmol/l (P=0.028); however there was no difference in the area under the curve 0-510 min between the two study days. Fat excretion was greater following orlistat (1017 (SEM 168) kJ) v. control (484 (SEM 90) kJ) (P=0.004). In conclusion, in healthy, lean subjects the acute inhibitory effect of fat on subsequent energy intake is attenuated by orlistat and the increase in energy intake approximates the energy lost due to fat malabsorption.
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PMID:Lipase inhibition attenuates the acute inhibitory effects of oral fat on food intake in healthy subjects. 1466 78

Lipase-catalyzed acetylation of cellulose solubilized in the dimethyl sulfoxide/paraformaldehyde organic solvent system was conducted with lipase A12 from Aspergillus niger. The accompanying side cellulase activity of the A. niger lipase partly accounted for the enhanced acetylation mediated by the enzyme, via facilitating the partial degradation of cellulose substrate as evidenced by high-performance size exclusion chromatograph analysis. The enzymatic cellulose acetylation was improved by substrate pretreatment with cellulase or ultrasound by 18 and 14%, respectively, as a result of the reduced substrate molecular size. Additionally, the ultrasound-pretreated cellulose as the starting substrate was beneficial for the cellulose solution preparation due to the increased accessible surface of cellulose as evidenced by its increased sedimentation volume and SEM micrographs. The effect of thermodynamic water activity (aw) on lipase catalytic activity in organic media was also investigated. The maximum acetylation extent (nearly 11 wt %) occurred at aw = 0.52, which was improved by 51% relative to the enzymatic reaction with no control of water activity. The much larger extent to which the lipase-catalyzed cellulose acetylation was enhanced by water activity optimization than by substrate pretreatment further supported the predominant role played by the major lipase activity of the A. niger lipase over its side cellulase activity in catalyzing cellulose ester synthesis in organic media.
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PMID:Effects of substrate pretreatment and water activity on lipase-catalyzed cellulose acetylation in organic media. 1529 29


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