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1.
Dis Esophagus ; 29(7): 747-751, 2016 Oct.
Article in English | MEDLINE | ID: mdl-26455587

ABSTRACT

In the past 30 years, the incidence of esophageal adenocarcinoma (EAC) has increased more rapidly than any other cancer in the United States. The prevalence of obesity and diabetes mellitus has drastically increased as well. We explored the potential association between obesity, diabetes mellitus, and EAC. By means of retrospective interrogation of an administrative database from fiscal year 2005-2009, we identified two cohorts. The cancer cohort was defined as patients with adenocarcinoma of the distal esophagus or gastric cardia. The comparison cohort contained patients with gastroesophageal reflux disorder (GERD; diagnosis coupled with a procedure code for fundoplication). Patient data, including demographic measures, diagnoses of obesity, diabetes mellitus, dyslipidemia, alcohol abuse, and nicotine dependence were examined. A logistic regression model identified risk factors for development of EAC. The sample included 2,836 patients identified as having either EAC (1,704) or fundoplication with GERD (1,132). Although slightly higher percentages of the benign cohort were obese, the cancer cohort had more diabetics (30.8% vs. 14.8%; chi-square = 94.5; P < 0.0001). In a logistic regression analysis adjusting for comorbidity and lifestyle factors, diagnosis of diabetes mellitus was significantly associated with esophageal cancer as opposed to GERD without cancer (OR = 2.2; 95% confidence interval [CI] 1.7-2.8). Nicotine dependence was also identified as a risk factor (OR = 1.7; 95% CI 1.4-2.0). We identified a potential association between diabetes mellitus and adenocarcinoma of the esophagus or gastric cardia. This association appears to be independent of obesity. Additionally, nicotine dependence was identified as a risk factor for EAC.


Subject(s)
Adenocarcinoma/etiology , Cardia , Diabetes Mellitus, Type 2/complications , Esophageal Neoplasms/etiology , Gastroesophageal Reflux/complications , Obesity/complications , Stomach Neoplasms/etiology , Adenocarcinoma/epidemiology , Aged , Chi-Square Distribution , Databases, Factual , Esophageal Neoplasms/epidemiology , Esophagus , Female , Fundoplication , Gastroesophageal Reflux/therapy , Humans , Logistic Models , Male , Middle Aged , Retrospective Studies , Risk Factors , Stomach Neoplasms/epidemiology , Tobacco Use Disorder/complications , United States/epidemiology , United States Department of Veterans Affairs/statistics & numerical data
3.
Gut ; 52(8): 1215-7, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12865285

ABSTRACT

BACKGROUND: A severe form of iron overload with the clinicopathological features of haemochromatosis inherited in an autosomal dominant manner has been described in the Solomon Islands. The genetic basis of the disorder has not been identified. The disorder has similarities to type 4 haemochromatosis, which is caused by mutations in ferroportin1. AIMS: The aims of this study were to identify the genetic basis of iron overload in a patient from the Solomon Islands. PATIENT AND METHODS: Genomic DNA was isolated from peripheral blood leucocytes of a Solomon Islands man with severe iron overload. The entire coding region and splice sites of the ferroportin1 gene was sequenced. RESULTS AND CONCLUSIONS: A novel missense mutation (431A>C; N144T) was identified in exon 5 of the ferroportin1 gene. A novel restriction endonuclease based assay which identifies both the N144T and N144H mutations was developed which will simplify the diagnosis and screening of patients for iron overload in the Solomon Islands and other populations. This is the first identified mutation associated with haemochromatosis in the Solomon Islands population.


Subject(s)
Cation Transport Proteins/genetics , Hemochromatosis/genetics , Mutation, Missense/genetics , Hemochromatosis Protein , Histocompatibility Antigens Class I/genetics , Humans , Male , Melanesia , Membrane Proteins/genetics , Middle Aged , Sequence Analysis, DNA
5.
J Pharmacol Exp Ther ; 306(1): 132-40, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12663685

ABSTRACT

Endothelin-1 (ET-1) signaling mechanisms have been implicated in the pathogenesis of excess coronary artery disease in diabetic dyslipidemia. We hypothesized that in diabetic dyslipidemia ET-1-induced coronary smooth muscle calcium (Ca2+m) and tyrosine phosphorylation would be increased, and the lipid lowering agent, atorvastatin, would inhibit these increases. Male Yucatan miniature swine groups were treated for 20 weeks: normal low-fat fed control, high-fat/cholesterol fed (hyperlipidemic), hyperlipidemic made diabetic with alloxan (diabetic dyslipidemic), and diabetic dyslipidemic treated with atorvastatin (atorvastatin-treated). Blood glucose values were 5-fold greater in diabetic dyslipidemic and atorvastatin-treated versus control and hyperlipidemic. Total and low-density lipoprotein (LDL) plasma cholesterol in hyperlipidemic, diabetic dyslipidemic, and atorvastatin-treated were approximately 5-fold greater than control. Intravascular ultrasound detectable coronary disease and hypertriglyceridemia were only observed in diabetic dyslipidemic and were abolished by atorvastatin. In freshly isolated cells, the Ca2+m response to ET-1 in diabetic dyslipidemic was greater than in control, hyperlipidemic, and atorvastatin-treated groups. Selective ET-1 receptor antagonists showed in the control group that the ETB subtype inhibits ETA regulation of Ca2+m. There was almost a complete switch of receptor subtype regulation of Ca2+m from largely ETA in control to an increased inhibitory interaction between ETA and ETB in hyperlipidemic and diabetic dyslipidemic groups, such that neither ETA nor ETB antagonist alone could block the ET-1-induced Ca2+m response. The inhibitory interaction was attenuated in the atorvastatin-treated group. In single cells, basal and ET-1-induced tyrosine phosphorylation in diabetic dyslipidemic were more than 3- and 6-fold greater, respectively, than in control, hyperlipidemic, and atorvastatin-treated. Attenuation by atorvastatin of coronary disease and ET-1-induced Ca2+m and tyrosine phosphorylation signaling with no change in cholesterol provides strong evidence for direct actions of atorvastatin and/or triglycerides on the vascular wall.


Subject(s)
Anticholesteremic Agents/therapeutic use , Calcium Signaling/physiology , Coronary Artery Disease/prevention & control , Diabetes Complications , Heptanoic Acids/therapeutic use , Hyperlipidemias/complications , Pyrroles/therapeutic use , Animals , Atorvastatin , Calcium/metabolism , Calcium Signaling/drug effects , Coronary Artery Disease/etiology , Diet , Disease Models, Animal , Endothelin-1/pharmacology , Endothelins/pharmacology , Male , Phosphorylation , Receptor, Endothelin A , Receptors, Endothelin/metabolism , Swine , Tyrosine/metabolism
6.
J Vasc Res ; 39(3): 208-20, 2002.
Article in English | MEDLINE | ID: mdl-12097819

ABSTRACT

Atorvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, alters bulk myoplasmic Ca2+ regulation and inhibits phenotypic modulation and proliferation of vascular smooth muscle in culture. Nuclear Ca2+ (Ca(n)) signaling is tightly coupled to transcriptional events and cell growth. Therefore, we hypothesized that in vivo treatment with atorvastatin would attenuate alterations in mitogen-induced Ca(n) signaling associated with coronary atherosclerosis. Three groups of male Yucatan pigs were treated for 20 weeks: controls, alloxan-induced diabetics fed an atherogenic diet and diabetics fed an atherogenic diet plus atorvastatin (80 mg/day). Right coronary artery single-cell cytosolic Ca2+ (Ca(c)) and Ca(n) responses to the mitogen endothelin-1 (5 x 10(-8) M) were measured by laser confocal microscopy using the calcium indicator Fluo-4. We observed a 39% increase in Ca(c) and a 52% increase in Ca(n) responses to endothelin-1 in cells from diabetic dyslipidemic arteries compared to control. These alterations were prevented in animals treated with atorvastatin. We show that during proliferation, the nucleus of a smooth muscle cell becomes rounded and loses the characteristic multilobular shape, clefts and invaginations. Consistent with this, a redistribution of Ca2+ stores from a transnuclear morphology in controls to a more perinuclear morphology occurred in cells from diabetic dyslipidemic arteries and was prevented by atorvastatin. In addition, the peak Ca(n) responses to endothelin-1 were inversely correlated (r = 0.712) with the extent of the transnuclear distribution of Ca2+ stores and directly correlated (r = 0.874) with the extent of atherosclerosis, as assessed in vivo by intravascular ultrasound. These findings indicate that chronic treatment with atorvastatin directly decreases mitogen-induced Ca(n) mobilization, which we suggest is related to the spatial localization of Ca(n) stores.


Subject(s)
Anticholesteremic Agents/therapeutic use , Calcium Signaling , Coronary Artery Disease/drug therapy , Diabetes Mellitus, Experimental/metabolism , Heptanoic Acids/therapeutic use , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Hypercholesterolemia/drug therapy , Muscle, Smooth, Vascular/drug effects , Pyrroles/therapeutic use , Alloxan/adverse effects , Animals , Anticholesteremic Agents/administration & dosage , Anticholesteremic Agents/pharmacology , Arteries/drug effects , Arteries/metabolism , Atorvastatin , Blood Glucose/analysis , Calcium/metabolism , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Cell Nucleus/pathology , Cell Nucleus/ultrastructure , Cells, Cultured , Cholesterol/blood , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Coronary Artery Disease/blood , Coronary Artery Disease/complications , Coronary Artery Disease/metabolism , Coronary Vessels/drug effects , Coronary Vessels/metabolism , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/chemically induced , Diabetes Mellitus, Experimental/complications , Endothelin-1/pharmacology , Heptanoic Acids/administration & dosage , Heptanoic Acids/pharmacology , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Hypercholesterolemia/blood , Hypercholesterolemia/complications , Hypercholesterolemia/metabolism , Male , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/metabolism , Pyrroles/administration & dosage , Pyrroles/pharmacology , Swine
7.
J Lipid Res ; 42(12): 1947-58, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11734567

ABSTRACT

The transport of apolipoprotein B (apoB) between the endoplasmic reticulum (ER) and Golgi was studied in puromycin-synchronized HepG2 cells, using an antibody that could distinguish between apoB in ER and Golgi compartments. In cells with normal ER-to-Golgi transport, both albumin and apoB colocalized throughout the ER and appeared as intense, compact signals in Golgi. When ER-to-Golgi transport was blocked with brefeldin A, apoB and albumin remained colocalized in the ER network and three-dimensional constructed images showed more intense signals for both proteins in a central, perinuclear region of the ER. When protein synthesis was stopped in cells with brefeldin A-inhibited ER-to-Golgi transport, apoB degradation was visualized as a homogeneous decrease in fluorescence signal intensity throughout the ER that could be slowed with clasto-lactacystin beta-lactone, a proteasome inhibitor. Incubation of cells with CP-10447, an inhibitor of microsomal triglyceride transfer protein, inhibited apoB, but not albumin, transport from ER to Golgi. Nanogold immunoelectron microscopy of digitonin-permeabilized cells showed proteasomes in close proximity to the cytosolic side of the ER membrane. Thus, newly synthesized apoB is localized throughout the entire ER and degraded homogeneously, most likely by neighboring proteasomes located on the cytosolic side of the ER membrane. Although albumin is colocalized with apoB in the ER, as expected, it was not targeted for ER-associated proteasomal degradation.


Subject(s)
Apolipoproteins B/metabolism , Endoplasmic Reticulum/metabolism , Golgi Apparatus/metabolism , Albumins/metabolism , Apolipoprotein B-100 , Brefeldin A/pharmacology , Cell Membrane Permeability , Cysteine Endopeptidases/metabolism , Digitonin/metabolism , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/ultrastructure , Golgi Apparatus/drug effects , Humans , Microscopy, Electron , Microscopy, Fluorescence , Multienzyme Complexes/antagonists & inhibitors , Multienzyme Complexes/metabolism , Proteasome Endopeptidase Complex , Protein Processing, Post-Translational , Protein Transport/drug effects , Puromycin/pharmacology , Tumor Cells, Cultured
8.
Atherosclerosis ; 159(1): 117-24, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11689213

ABSTRACT

Intracellular Ca(2+) store loading has been shown to alter proliferation and apoptosis of several cell types. In addition, HMG-CoA reductase inhibitors (i.e. atorvastatin) are effective in treating diabetic dyslipidemic patients. Thus, we hypothesized that chronic atorvastatin treatment would prevent increased Ca(2+) uptake into intracellular Ca(2+) stores in vascular smooth muscle cells from diabetic dyslipidemic pigs. Male Yucatan pigs were divided into four groups for 20 weeks-- (1) low fat fed (control); (2) hyperlipidemic (F); (3) alloxan-induced diabetic dyslipidemic (DF); and (4) diabetic dyslipidemic pigs treated with atorvastatin (DFA). The F, DF, and DFA groups were fed a high fat/cholesterol diet. Cells were isolated from the coronary artery and the myoplasmic Ca(2+) (Ca(m)) response measured using single cell fura-2 imaging. The Ca(m) response to caffeine (5 mM to release Ca(2+) from the sarcoplasmic reticulum, SR) and ionomycin (10 microM; to release the total Ca(2+) store) was determined in either the presence of low Na (19Na; inhibits Na(+)-Ca(2+) exchange), thapsigargin (TSG; inhibits the SR Ca(2+) pump), and a 19Na+TSG solution. Low Na induced the uptake of Ca(2+) into both SR and non-SR Ca(2+) stores in the DF group, but not the DFA group. Furthermore, after depletion of the SR Ca(2+) store with TSG, 19Na evoked Ca(2+) uptake into non-SR Ca(2+) stores in all three groups except in the DFA group. In summary, this study demonstrates that atorvastatin prevents the enhanced uptake of Ca(2+) by SR and non-SR Ca(2+) stores in diabetic dyslipidemic pigs.


Subject(s)
Calcium/metabolism , Coronary Vessels/metabolism , Diabetes Mellitus, Experimental/metabolism , Diet, Atherogenic , Heptanoic Acids/pharmacology , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Hyperlipidemias/metabolism , Muscle, Smooth, Vascular/metabolism , Pyrroles/pharmacology , Animals , Atorvastatin , Caffeine/pharmacology , Cytoplasm/metabolism , Diabetes Mellitus, Experimental/complications , Fluorescent Dyes , Fura-2 , Hyperlipidemias/complications , In Vitro Techniques , Ionomycin/pharmacology , Ionophores/pharmacology , Male , Microscopy, Fluorescence , Muscle, Smooth, Vascular/cytology , Sarcoplasmic Reticulum/metabolism , Sodium/pharmacology , Swine , Swine, Miniature , Thapsigargin/pharmacology
9.
Mol Cell Biochem ; 217(1-2): 99-106, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11269671

ABSTRACT

High cholesterol, especially LDL cholesterol, has been associated with the development of atherosclerotic plaques in arteries. To investigate the changes in cellular substrate metabolism early in the atherogenic process, Sinclair miniature swine were treated for 12 weeks with either a control diet, a high fat diet, or a high fat diet with the addition of alloxan to induce diabetes. The fractional entry into the TCA cycle of 1,2-(13)C-acetate (5 mM), 1-(13)C-glucose (5 mM), and unlabeled, endogenous lipids was determined in control, hyperlipidemic, and diabetic/hyperlipidemic pigs using 13C-isotopomer analysis of glutamate. The diabetic state of the pigs was validated by plasma glucose measurements made after 10 weeks of alloxan treatment for control (65 +/- 6 mg/dL), hyperlipidemic (63 +/- 5 mg/dL), and diabetic/hyperlipidemic (333 +/- 52 mg/dL) pigs. Plasma glucose values did not correlate with the percentage of glucose entry into the TCA cycle (R2 = 0.0819, n = 10). Alterations in the pattern of substrate oxidation were better correlated with changes in plasma lipids (cholesterol and triglycerides) than with changes in plasma glucose. Plasma total cholesterol and total triglyceride levels significantly correlated with changes in acetate metabolism (R2 = 0.7768 and R2 = 0.4787, respectively) and with changes in glucose metabolism (R2 = 0.6067 and R2 = 0.4506, respectively). We conclude that alterations in lipid profile, especially those that were observed in the diabetic milieu, are associated with early changes in vascular smooth muscle oxidative metabolism. These changes in oxidative metabolism may precede alterations in smooth muscle phenotype and, therefore, may play an important role in the early pathogenesis of atherosclerosis.


Subject(s)
Acetates/metabolism , Diabetes Mellitus, Experimental/metabolism , Glucose/metabolism , Hyperlipidemias/metabolism , Muscle, Smooth, Vascular/metabolism , Animals , Blood Glucose/metabolism , Cholesterol/blood , Cholesterol, HDL/metabolism , Cholesterol, LDL/blood , Citric Acid Cycle , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/complications , Glutamates/metabolism , Hyperlipidemias/blood , Hyperlipidemias/complications , Male , Oxidation-Reduction , Swine , Swine, Miniature , Triglycerides/blood
10.
Microb Ecol ; 42(4): 549-561, 2001 Dec.
Article in English | MEDLINE | ID: mdl-12024238

ABSTRACT

Bacteria play a major role in the decomposition of organic matter arriving at the deep-sea floor, and hence there is a need to determine accurate rates of bacterial production associated with sediment particles. However, sediment-based procedures are not well defined and sampling deep-sea sediments is technically difficult, time consuming, and expensive, often only producing relatively small amounts of undisturbed sediment for analysis. We describe and test a small-scale method (requiring 0.25 ml sediment) for the examination of bacterial production in deep-sea calcium carbonate rich sediments. Time course experiments showed variation in the period of linear [3H]thymidine uptake between 1 and 3 hr depending on station depth. The average concentration of natural thymidine in deep-sea sediments was 0.61 nmol per 0.5 ml slurry sample. Isotope dilution was significant, ranging between 26 and 51%. There was substantial small-scale (0.2-1.0 m) variation in deep-sea benthic bacterial [3H]thymidine incorporation rates (39%). Deep-sea surficial sediment bacterial production (assuming zero isotope dilution due to its potential high variability) in surficial sediments of the deep NE Atlantic varied between 0.014 and 0.48 mg C g-1 d-1 (mean = 0.23 mg C g-1 d-1) over 3 locations of depths between 1,092 and 3,572 m and at 3 times. Bacterial biomass varied between 1.1 and 12 mg C g-1 (mean = 6.1 mg C g-1). Bacterial growth rate estimates in these deep-sea sediments varied between 0.003 and 0.13 d-1 (mean = 0.050 d-1) giving doubling times of 5.3-216 d (mean = 44.5 d); which are similar to those of bacteria inhabiting waters in the upper mixed layer (2-<40 m) of the water column (2.6-57.8 d). comparison with shallow and coastal sea sediments (0.13-116 d) indicates that deep-sea sediment bacteria in the NE Atlantic are able to grow at rates similar to those in shallow sediment systems given sufficient food. However, the range is broader for deep-sea sediment bacteria, which may indicate a more "feast" and "fast" life than their counterparts in shallower environments. waters >2,000 m cover 60% of the Earth's surface; thus bacterial production in deep-sea sediments must contribute an important fraction of oceanic and global bacterial production. It is therefore important to establish an accurate method of measuring bacterial production so that the full roles and controls of bacteria from this environment can be determined.

11.
Arterioscler Thromb Vasc Biol ; 19(12): 2981-92, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10591679

ABSTRACT

Diabetic patients typically have not only hyperglycemia but also dyslipidemia. Study of the pathogenic components of the diabetic milieu and mechanisms of accelerated atherosclerosis is hindered by inadequate animal models. A potentially suitable animal model for human diabetic dyslipidemia is the pig, because it carries a large fraction of total cholesterol in low-density lipoprotein (LDL), similar to humans. In this study, male Sinclair miniature pigs were made diabetic by destroying the insulin-producing cells of the pancreas with alloxan and then were fed a high fat and high cholesterol diet for comparison with pigs fed a nondiabetic high fat and high cholesterol diet and control pigs. Diabetic pigs exhibited hyperglycemia, but plasma urea nitrogen, creatinine, and transaminase levels were in the normal range, indicating no adverse effects on kidney and liver function. The lipoprotein profile in diabetic pigs was similar to that found in human diabetic patients and was characterized by hypertriglyceridemia (2.8-fold increase versus control and high fat-fed pigs) and a profound shift of cholesterol distribution into the LDL fraction (81%) versus the distribution in high fat-fed (64%) and control (57%) pigs. LDL particles were lipid-enriched and more heterogeneous in diabetic pigs. Apolipoprotein B was distributed among a much broader spectrum of LDL particles, and apolipoprotein E was partially redistributed from high-density lipoprotein to apolipoprotein B-containing lipoproteins in diabetic pigs. There was little change in apolipoprotein A-I distribution. Diabetic pigs showed several early signs of excess vascular disease. In diabetic pigs, 75% of the coronary artery segments showed contractile oscillations in response to prostaglandin F(2alpha) compared with 25% in high fat-fed pigs and 10% in control pigs. Endothelium-dependent relaxation of brachial arteries was nearly abolished in diabetic pigs but unchanged in high fat-fed versus control pigs. Carotid artery Sudan IV staining for fatty streaks was significantly increased only in diabetic pigs. This porcine model should provide insights into the etiology of human diabetic dyslipidemia and facilitate study of peripheral vascular and coronary artery disease in diabetic patients.


Subject(s)
Arteriosclerosis/complications , Diabetes Mellitus, Experimental/complications , Diet, Atherogenic , Hyperlipidemias/complications , Animals , Arteriosclerosis/blood , Azo Compounds , Blood Glucose , Blood Urea Nitrogen , Carotid Arteries/chemistry , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Cholesterol, VLDL/blood , Chromatography, Liquid/methods , Coronary Vessels/metabolism , Coronary Vessels/physiology , Creatinine/blood , Diabetes Mellitus, Experimental/blood , Dietary Fats/administration & dosage , Disease Models, Animal , Electrophoresis, Polyacrylamide Gel , Endothelium, Vascular/metabolism , Fats/analysis , Hyperlipidemias/blood , Kidney/physiology , Liver/physiology , Male , Muscle, Smooth, Vascular/metabolism , Swine , Swine, Miniature , Triglycerides/blood , Vasoconstriction/physiology
12.
J Biol Chem ; 274(24): 17068-74, 1999 Jun 11.
Article in English | MEDLINE | ID: mdl-10358059

ABSTRACT

Recent studies have proposed that post-translational degradation of apolipoprotein B100 (apoB) involves the cytosolic ubiquitin-proteasome pathway. In this study, immunocytochemistry indicated that endoplasmic reticulum (ER)-associated proteasome molecules were concentrated in perinuclear regions of digitonin-permeabilized HepG2 cells. Signals produced by antibodies that recognize both alpha- and beta-subunits of the proteasome co-localized in the ER with specific domains of apoB. The mechanism of apoB degradation in the ER by the ubiquitin-proteasome pathway was studied using pulse-chase labeling and digitonin-permeabilized cells. ApoB in permeabilized cells incubated at 37 degrees C in buffer alone was relatively stable. When permeabilized cells were incubated with both exogenous ATP and rabbit reticulocyte lysate (RRL) as a source of ubiquitin-proteasome factors, >50% of [3H]apoB was degraded in 30 min. The degradation of apoB in the intact ER of permeabilized cells was much more rapid than that of extracted [3H]apoB incubated with RRL and ATP in vitro. The degradation of apoB was reduced by clasto-lactacystin beta-lactone, a potent proteasome inhibitor, and by ubiquitin K48R mutant protein, an inhibitor of polyubiquitination. ApoB in HepG2 cells was ubiquitinated, and polyubiquitination of apoB was stimulated by incubation of permeabilized cells with RRL. These results suggest that newly synthesized apoB in the ER is accessible to the cytoplasmic ubiquitin-proteasome pathway and that factors in RRL stimulate polyubiquitination of apoB, leading to rapid degradation of apoB in permeabilized cells.


Subject(s)
Apolipoproteins B/metabolism , Cysteine Endopeptidases/metabolism , Cytosol/metabolism , Multienzyme Complexes/metabolism , Animals , Apolipoproteins B/isolation & purification , Cell Compartmentation , Cell Membrane Permeability , Cysteine Endopeptidases/isolation & purification , Endoplasmic Reticulum/enzymology , Models, Biological , Multienzyme Complexes/isolation & purification , Proteasome Endopeptidase Complex , Protein Processing, Post-Translational , Rabbits , Reticulocytes/metabolism , Ubiquitins/metabolism
13.
Biochim Biophys Acta ; 1437(1): 71-9, 1999 Jan 29.
Article in English | MEDLINE | ID: mdl-9931444

ABSTRACT

Apolipoprotein B100 (apoB) is a large secretory protein that forms very low density lipoprotein in liver. An in vitro degradation assay was developed using rabbit reticulocyte (RR) lysate in order to investigate the mechanism of intracellular degradation of newly synthesized apoB by the ubiquitin-proteasome pathway. [3H]apoB, isolated from [3H]leucine pulsed/chased Hep G2 cells, was degraded 51% when incubated for 2 h at 37 degreesC in an assay mixture that included RR lysate (source of the ubiquitin conjugation system and proteasome) and an exogenous ATP regenerating system. ApoB degradation was ATP-dependent and degradation fragments were not observed suggesting that the very large apoB molecule was extensively degraded. ApoB degradation was decreased to 50% when potent proteasome inhibitors, clasto-lactacystin beta-lactone (10 microM) or MG-132 (50 microM), were added to the reaction mixture, but was not affected by the cysteine protease inhibitor, E-64, or the serine protease inhibitor, phenylmethylsulfonyl fluoride. ApoB degradation was inhibited by the mutant ubiquitin protein K48R and by ubiquitin aldehyde, an inhibitor of ubiquitin-protein isopeptidases. During incubation ubiquitination of apoB increased even as apoB was being degraded. These results suggest that in vitro degradation of apoB, a large secretory protein that is normally found in the endoplasmic reticulum (ER) lumen or associated with the ER membrane, was proteasome-dependent and involved both ubiquitination and deubiquitination steps.


Subject(s)
Apolipoproteins B/metabolism , Peptide Hydrolases/metabolism , Reticulocytes/metabolism , Ubiquitins/metabolism , Adenosine Triphosphate/metabolism , Animals , Apolipoprotein B-100 , Apolipoproteins B/chemistry , Apolipoproteins B/isolation & purification , Cell Line , Immunoblotting , Protease Inhibitors/pharmacology , Rabbits , Time Factors , Tritium , Ubiquitins/analysis
14.
J Cell Biol ; 141(3): 585-99, 1998 May 04.
Article in English | MEDLINE | ID: mdl-9566961

ABSTRACT

Protease protection assays of apolipoprotein B100 (apoB) in digitonin-permeabilized HepG2 cells indicated that multiple domains of apoB are exposed to the cytosol through an extensive portion of the secretory pathway. The intracellular orientation of apoB in the secretory pathway was confirmed by immunocytochemistry using antibodies recognizing specific domains of apoB in streptolysin-O (STP-O)- and saponin-permeabilized HepG2 cells. Lumenal epitopes on marker proteins in secretory pathway compartments (p63, p53, and galactosyltransferase) were not stained by antibodies in STP-O-treated cells, but were brightly stained in saponin-treated cells, confirming that internal membranes were not perforated in STP-O-treated cells. An anti-apoB peptide antibody (B4) recognizing amino acids 3221-3240 caused intense staining in close proximity to the nuclear membrane, and less intensely throughout the secretory pathway in STP-O-permeabilized cells. Staining with this antibody was similar in STP-O- and saponin-treated cells, indicating that this epitope in apoB is exposed to the cytosol at the site of apoB synthesis and throughout most of the remaining secretory pathway. Similar results indicating a cytosolic orientation were obtained with monoclonal antibody CC3.4, which recognizes amino acids 690-797 (79-91 kD) in apoB. Two polyclonal antibodies made to human LDL and two monoclonal antibodies recognizing amino acids 1878-2148 (D7.2) and 3214-3506 (B1B6) in apoB did not produce a strong reticular signal for apoB in STP-O-treated cells. The anti-LDL and B1B6 antibodies produced almost identical punctate patterns in STP-O-treated cells that overlapped with LAMP-1, a membrane marker for lysosomes. These observations suggest that the B1B6 epitope of apoB is exposed on the surface of the lysosome. The results identify two specific regions in apoB that are exposed to the cytosol in the secretory pathway.


Subject(s)
Apolipoproteins B/metabolism , Endoplasmic Reticulum/metabolism , Intracellular Membranes/metabolism , Amino Acid Sequence , Animals , Antibodies/immunology , Antibodies, Monoclonal/immunology , Antigens, CD/analysis , Apolipoprotein B-100 , Apolipoproteins B/chemical synthesis , Apolipoproteins B/immunology , Binding Sites , Cell Membrane Permeability , Cytosol/metabolism , Digitonin , Endopeptidase K/metabolism , Fluorescent Antibody Technique, Indirect , Humans , Immunoblotting , Isotope Labeling , Lysosomal Membrane Proteins , Lysosomes , Membrane Glycoproteins/analysis , Molecular Sequence Data , Peptides/chemical synthesis , Rabbits , Sheep , Staining and Labeling , Tritium , Tumor Cells, Cultured
15.
Percept Mot Skills ; 86(1): 195-7, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9530731

ABSTRACT

This study evaluated the concurrent validity of Koppitz' revised Bender-Gestalt Emotional Indicators among 44 women with mental retardation. The concurrent validity of the Emotional Indicator total score was not supported when compared with responses on two widely used and accepted screening inventories, the Reiss Screen and the Inventory for Client and Agency Planning.


Subject(s)
Affective Symptoms/diagnosis , Bender-Gestalt Test/statistics & numerical data , Intellectual Disability/diagnosis , Adult , Affective Symptoms/epidemiology , Affective Symptoms/psychology , Aged , Comorbidity , Diagnosis, Differential , Female , Humans , Intellectual Disability/epidemiology , Intellectual Disability/psychology , Middle Aged , Psychiatric Status Rating Scales/statistics & numerical data , Psychometrics , Reproducibility of Results
16.
Lipids ; 32(8): 811-23, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9270972

ABSTRACT

2-Hydroxypropyl-beta-cyclodextrin (cyclodextrin), cyclodextrin-solubilized oleate, and cyclodextrin-solubilized cholesterol were used to modulate proteolysis and secretion of newly-synthesized apolipoprotein B-100 (apoB) in HepG2 cells. Following cyclodextrin and lipid treatments, cells were pulse-labeled with [3H] leucine, and quantitative immunoprecipitation was used to measure apoB synthesis, apoB secreted into the medium, and the cellular content of undegraded apoB that was not secreted. Three-hour treatment with cyclodextrin-solubilized oleate (0.2 mM) increased secreted apoB from 4% (control cells) to 32% and cellular undegraded apoB from 15% (control cells to 64% of apoB synthesized, which is consistent with earlier studies using bovine serum albumin to complex exogenous oleate. Prolonged daily (4 d or more) administration of 0.5% (3.5 mM) cyclodextrin with medium containing 10% fetal bovine serum increased the secretion of nascent apoB from 5-10% (control) to 17-28% and cellular undegraded apoB from 15-20% (control) to 25-31% of apoB synthesized, respectively. Subsequent administration of cyclodextrin solubilized cholesterol (10-40 micrograms) for only 3 h reversed the cyclodextrin-mediated increase in apoB secretion. The application of 0.5% cyclodextrin to HepG2 cells can rapidly (within minutes) stimulate cholesterol efflux, and transiently (over a 1-2 d period) increase cholesterol synthesis. In the current studies, the cyclodextrin-mediated increase in cholesterol synthesis was not concurrent with the increase in apoB secretion. However, prolonged (15 d) administration of cyclodextrin was shown to increase the cellular free cholesterol concentration by 25-41%, reduce the cellular triglyceride concentration by 59%, and increase apoB secretion 3- to 4-fold, without affecting the cellular cholesteryl ester concentration. In comparison, 14-d treatment with cyclodextrin-solubilized cholesterol (20 micrograms/mL) followed by 1-d equilibration without cholesterol was shown to increase the cellular free cholesterol and cholesteryl ester concentrations by 76% and 10-fold, respectively, although apoB secretion was not affected. It is hypothesized that chronic daily administration of 0.5% cyclodextrin increased the cellular cholesterol concentration and flux in discrete putative regulatory compartments, which "shielded" nascent apoB from rapid proteolysis and facilitated apoB secretion. In conclusion, cyclodextrin was used independently and in combination with cholesterol or oleate to modulate apoB proteolysis and secretion. We speculate that subcellular changes in cholesterol concentration and flux may modulate apoB production in HepG2 cells.


Subject(s)
Apolipoproteins B/metabolism , Cholesterol/metabolism , Cyclodextrins/pharmacology , Oleic Acid/metabolism , beta-Cyclodextrins , 2-Hydroxypropyl-beta-cyclodextrin , Acetic Acid/metabolism , Apolipoprotein B-100 , Apolipoproteins B/biosynthesis , Electrophoresis, Polyacrylamide Gel , Endopeptidases/metabolism , Humans , Liver Neoplasms , Oleic Acid/pharmacology , Proteins/metabolism , Solubility , Tumor Cells, Cultured
18.
Paediatr Anaesth ; 6(4): 265-70, 1996.
Article in English | MEDLINE | ID: mdl-8827741

ABSTRACT

Forty-nine children having day-stay surgical procedures were randomly assigned to receive oral midazolam 0.75 mg.kg-1 or placebo in a double blind fashion. The child's level of anxiety was assessed before premedication using parental, child and observer scales. The child and observer anxiety scores were repeated in the anaesthetic room. Most children presented for anaesthesia in a calm state, irrespective of whether they had received midazolam. Parents tended to overestimate their child's level of anxiety. Observer anxiety scores reliably predicted behaviour during induction of anaesthesia in the absence of a sedative. Observer scores decreased in the midazolam group (P < 0.02), but not in the placebo group, children below six years having the greatest decrease with midazolam. The median time to discharge from hospital was delayed by 30 min in the midazolam group (P < 0.01). Children do not require routine sedative premedication for day case procedures, but oral midazolam is useful in producing calm behaviour in those children with high observer anxiety scores.


Subject(s)
Ambulatory Surgical Procedures , Hypnotics and Sedatives/administration & dosage , Midazolam/administration & dosage , Preanesthetic Medication , Administration, Oral , Anxiety , Child , Child, Preschool , Double-Blind Method , Humans , Infant , Prospective Studies
19.
Kidney Int ; 47(2): 421-31, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7536855

ABSTRACT

It is generally accepted that hepatic secretion of apoprotein (apo) B-containing lipoproteins is substantially increased in nephrosis. To elucidate the mechanisms for the oversecretion of apo B, we investigated the effect of a various concentration of albumin on apo B kinetics in the absence or presence of oleate in Hep G2 cells. Hep G2 cells were labeled with [3H]-leucine in leucine-free medium containing 0, 1.5, 3.0 or 4.5% BSA for 180 minutes, and the secreted radiolabeled apo B, apo A1 and albumin were isolated by immunoprecipitation and counted. The secretions of apo B and albumin were suppressed by BSA (bovine serum albumin) in a dose-dependent manner, but the secretion of apo A1 was not suppressed significantly. Oleate (0.4 mM) increased the rate of apo B secretion by 2.5-fold when oleate was bound to 1.5% BSA, but at higher concentrations of BSA (3.0 or 4.5%), apo B secretion was less responsive to oleate. A pulse-chase study indicated that early apo B degradation was significantly suppressed in cells incubated with lower concentrations of BSA (0 or 1.5% BSA), thereby rapidly stimulating apo B secretion. Oleate (0.4 mM) potently inhibited apo B degradation when oleate was bound to 1.5% BSA, whereas the inhibition was not observed when oleate was bound to 4.5% BSA. Intracellular albumin synthesis was stimulated in BSA-free medium, but intracellular decay of albumin was essentially unaffected by concentration of BSA. Similar to BSA, a higher concentration of dextran (3.0 or 4.5%) reduced apo B secretion, and this was the result of increased early apo B degradation in the cells. These results indicate that reduced albumin suppresses intracellular apo B degradation, and the inhibition of apo B degradation by oleate is manifested only at a low concentration of albumin. Therefore, the present study suggests that free fatty acids bound to low concentration of albumin in the circulating plasma play an important role on hepatic oversecretion of apo B-containing lipoprotein in hypoalbuminemic state, such as nephrotic syndrome.


Subject(s)
Apolipoproteins B/antagonists & inhibitors , Carcinoma, Hepatocellular/metabolism , Intracellular Membranes/metabolism , Liver Neoplasms/metabolism , Serum Albumin/metabolism , Apolipoprotein A-I/metabolism , Apolipoproteins B/metabolism , Carcinoma, Hepatocellular/pathology , Culture Media/metabolism , Dextrans/pharmacology , Humans , Kinetics , Liver Neoplasms/pathology , Oleic Acid , Oleic Acids/pharmacology , Osmolar Concentration , Serum Albumin, Bovine/pharmacology , Tumor Cells, Cultured
20.
Medinfo ; 8 Pt 2: 1634, 1995.
Article in English | MEDLINE | ID: mdl-8591520

ABSTRACT

1. HISTORY. The program began in 1986 as the Resource Management Initiative and had just six pilot sites. In 1989, Ministers decided to establish a national Resource Management Programme covering all general acute Hospitals in England with more than 250 beds--some 250-260 sites in all. A range of community units also embarked on a program of pilot projects aimed at testing the RM principles in those services. 2. ELEMENTS OF THE PROGRAM. A site joining the program was expected to submit a case based on readiness for inclusion, supported by an outline project plan before approval could be given. The plan encompassed a range of elements, but was individual to each unit; the philosophy being that each unit was being assisted to reach its own objectives within an overall framework. The elements of the framework were as follows: a) A vision of what was expected to be achieved by the project and the benefits being sought; b) A focus on improving the quality of patient care in the unit; c) Involving clinicians in the management process; d) The availability of clinical information to support decision-making; this included the hardware and software for Case-Mix Management and Nurse Management Systems, but also extended to coding, classifying, and grouping systems. e) A greater awareness of the financial implications of clinical decisions; f) A project management approach to implementation; g) An approach based on developing both the organization and its staff, with training. 3. THE KEY TO RM IMPLEMENTATION IS CULTURAL CHANGE AT THE UNIT LEVEL. While steps to achieve this change can be planned and driven forward via the project plan, the very nature of the project means that a more flexible and "soft systems" view of success is appropriate. Local ownership of the process is essential and can lead to a very specific view of "success." 4. BENEFITS. Demonstrating primary causality is difficult as eight years have elapsed since the program was started, and this has coincided with a period of radical change. However certain matters are beyond dispute: The vast majority of units have adopted one form or other of Clinical Directorate structure. Many clinical staff are formally engaged in the operational and general management process. Some RM sites are advantageous when it comes to negotiating with their purchaser organizations because they have better quality data on which to base the process. The use of Casemix Management and Nurse Management Systems is seen in some RM sites as improving the quality of patient care provided. RM has focused attention on clinical coding and grouping. RM has exposed the need to develop or reassess Information Strategies at unit level. RM has stimulated staff training and development at site level and has been instrumental in improving the quality of training facilities, resources, and materials that are available. RM is recognized as having had a catalytic effect on changes associated with the NHS Reforms. 5. CONCLUSION. Good quality services require well-managed and competent provider organizations. The RM program was designed to assist the improvement of provider unit management. There is general agreement that the principles of RM should be taken forward in the broader context of provider development, with a focus on quality as well as financial issues.


Subject(s)
Health Resources/organization & administration , Hospitals, Public/organization & administration , State Medicine/organization & administration , England
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