Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of obesity on the connective tissue composition of skin was investigated in mice with goldthioglucose (GTG)-induced obesity. Four months after GTG treatment, the obese animals were sacrificed. Acid mucopolysaccharides, glycoproteins, collagen, and elastin were analyzed in the skin and compared to the controls. Total MPS in the skin from obese animals decreased, reflected mostly in hyaluronic acid. Chondroitin showed an increase over controls. The content of soluble glycoproteins varied; total carbohydrate and sialic acid of the glycoprotein tended to increase with obesity. Collagen and elastin both tended to decrease with obesity.
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PMID:A study of connective tissue macromolecules in skin of mice with goldthioglucose-induced obesity. 12 61

In an effort to determine if structural variation in proteins important in bone metabolism might influence bone mineral density (BMD) and thus be a determinant of susceptibility to osteoporosis in older women, the authors typed a group of 258 non-Black women (age 65-90) participating in the Study of Osteoporotic Fractures (SOF) for two polymorphic bone-related proteins, group specific component (Gc), also known as vitamin D-binding protein, and alpha 2HS glycoprotein (AHSG). These two proteins exhibit common structural variation in populations that can be detected by isoelectric focusing/immunoblotting of serum. An important function of Gc is the binding, solubilization, and transport of vitamin D sterols in the bloodstream while AHSG is a glycoprotein constituent of calcified cortical bone matrix. There are six common phenotypes of Gc and four of AHSG. Using Gc or AHSG phenotypes as categorical variables, statistical analyses were done to determine if bone mineral density of the proximal or distal radius or calcaneus differed by phenotype. Neither Gc nor AHSG phenotype demonstrated a statistically significant relationship with BMD at any site. Adjustments for age and degree of obesity did not substantively affect these results. Subsequent analyses to determine if phenotype of either of these proteins was associated with variables related to skeletal size showed an association of AHSG with height (P less than .02). This may indicate that AHSG phenotype is related to postmenopausal loss of height, or it may be a chance statistical finding.
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PMID:Genetic variation in two bone-related proteins: is there an association with bone mineral density or skeletal size in postmenopausal women? 152 79

There are two types of gallstones; cholesterol and pigment or bilirubinate. Cholesterol stones are formed in the gallbladder as a consequence of altered hepatocellular and gallbladder function. Overproduction of cholesterol by the liver is the major metabolic precedent of cholesterol gallstones and this may occur because of obesity, drugs, or other factors. Gallbladder factors which promote stone formation include hypomotility and the secretion of nucleating factors such as mucus glycoprotein. It is possible that both of these two factors are mediated by an increase in the prostaglandin production by the gallbladder mucosa. Pigment stones are either brown or black. Brown stones are formed of calcium bilirubinate and are usually associated with biliary infection. They occur in both the gallbladder and the bile ducts. Black pigment stones are extremely hard bilirubin polymers and are found mainly in the gallbladder. Biliary sludge is a necessary precedent of gallstones. It comprises cholesterol monohydrate crystals, glycoproteins and granules of calcium bilirubinate.
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PMID:The formation of gallstones. 158 12

Lignocaine (lidocaine) and beta-adrenoceptor antagonists are widely used after acute myocardial infarction. The therapeutic value of these agents depends on the achievement and maintenance of safe and effective plasma concentrations. Lignocaine pharmacokinetics after acute myocardial infarction (MI) are controlled by a number of variables. The single most important is left ventricular function, which affects both volume of distribution and plasma clearance. Other major factors include bodyweight, age, hepatic function, the presence of obesity, and concomitant drug therapy. Lignocaine is extensively bound to alpha 1-acid glycoprotein, a plasma protein which is also an acute phase reactant. Increases in alpha 1-acid glycoprotein concentration occur after an acute MI, decreasing the free fraction of lignocaine in the plasma and consequently decreasing total plasma lignocaine clearance without altering the clearance of non-protein-bound lignocaine. Complex changes in lignocaine disposition occur with long term infusions, and therefore early discontinuation of lignocaine infusions (within 24 hours) should be undertaken whenever possible. Because the risk of ventricular tachyarrhythmia declines rapidly after the onset of an acute MI, lignocaine therapy can be rationally discontinued within 24 hours in most patients. Lignocaine has a narrow toxic/therapeutic index, so that pharmacokinetic factors are critical in dose selection. In contrast, beta-adrenoceptor antagonists' adverse effects are more related to the presence of predisposing conditions (such as asthma, heart failure, bradyarrhythmias, etc.) than to plasma concentration. The pharmacokinetics of beta-adrenoceptor antagonists are important to help assure therapeutic efficacy, to provide information about the anticipated time course of drug action, and to predict the possible role of ancillary drug effects (such as direct membrane action) and loss of cardioselectivity. Lipid solubility is the main determinant of the pharmacokinetic properties of a beta-adrenoceptor antagonist. Lipid-soluble agents like propranolol and metoprolol are well absorbed orally, and undergo rapid hepatic metabolism, with important presystemic clearance and a short plasma half-life. Water-soluble drugs like sotalol, atenolol, and nadolol are less well absorbed, and are eliminated more slowly by renal excretion. Clinical assessment of beta-adrenoceptor antagonism is more valuable than plasma concentration determinations in evaluating the adequacy of the dose of a particular beta-adrenoceptor antagonist.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The pharmacokinetics of lignocaine and beta-adrenoceptor antagonists in patients with acute myocardial infarction. 289 61

The insulin receptor is a glycoprotein with a molecular weight in the order of 300,000. There are probably two pairs of subunits joined together by disulphide bonds. The distribution of receptors appears to be tissue-specific. On liver plasma membranes they are found predominantly as singletons, whereas on adipocytes they occur mainly in groups. The groups of receptors are held together by disulphide bonds, but these are different from the bonds holding the subunits together. When insulin binds to the receptor, the hormone-receptor complex is internalised in pinocytotic invaginations in the adipocyte, and in coated pits in fibroblasts. Half the receptors are transported to lysosomes where they are degraded, and the other half are recycled to the cell surface presumably for further re-utilisation. Obese patients and those with type II diabetes have in common both a reduced number of insulin receptors and a post-receptor defect. However the degree of insulin resistance in type II diabetes cannot be accounted for on the basis of obesity alone. Moreover many type II diabetics are not obese. The insulin receptor is also altered in certain physiological states. Fasting and exercise lead to increased binding of insulin to its receptor. Pregnancy, on the other hand, may either increase or reduce binding. The effects of glucocorticoids are heterogeneous, and it is probable that the insulin resistance they induce is post-receptor in nature. Auto-antibodies to the insulin receptor is a rare cause of severe insulin-resistant diabetes, but the condition has given considerable insight into the nature of the insulin receptor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The insulin receptor. 299 44

Physiologic changes associated with obesity and their effects on the distribution, protein binding, metabolism, and renal excretion of drugs are described. Changes in the volume of distribution correlate with drug lipophilicity. Drugs that have a high affinity for adipose tissue have an increased volume of distribution, whereas the distribution of drugs that have low partition coefficients is not altered substantially. Albumin and total protein concentrations are comparable in lean and obese subjects, but concentrations of alpha 1-acid glycoprotein are increased. Consequently, protein binding of acidic drugs is unchanged, but the free fraction of basic drugs may be decreased. Changes in hepatic drug clearance are complex. Phase 1 reactions and acetylation, a Phase 2 reaction, appear to be unaffected by obesity, but activity of Phase 2 glucuronidation and sulfation pathways is enhanced. Available physiologic and pharmacokinetic data on the effect of obesity on systemic clearance of highly extracted drugs are conflicting. Both glomerular filtration and tubular secretion appear to be increased in obese individuals, and tubular secretion may be disproportionately increased compared with filtration. Clearance of drugs that depend on glomerular filtration for elimination is consistently higher in obese subjects. Differences among patient populations, other conditions associated with obesity, and the small study populations described to date may account for some discrepancies in reported results. Awareness of the physiologic effects of obesity is essential for ensuring appropriate drug therapy in obese patients.
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PMID:Influence of obesity on drug disposition. 331 2

Drug disposition for many drugs has now been studied in obese individuals and some general conclusions can be drawn. Absorption of drugs evaluated to date is unchanged due to obesity. Apparent volume of distribution is greatly increased for some drugs including most benzodiazepines, thiopentone, phenytoin, verapamil and lignocaine (lidocaine). Modest increases in volume of distribution have been noted for methylxanthines, aminoglycosides, vancomycin, ibuprofen, prednisolone and heparin. Distribution of digoxin, cimetidine and procainamide is unchanged in obesity. The mechanism for the increased distribution of some drugs and unchanged distribution of others in obesity is unclear at present. It may be in part due to the lipophilic character of the drug molecule; however, other complex and as yet poorly understood factors contribute to the variability in drug distribution in obese patients. Protein binding of drugs bound to albumin is not dramatically changed in obesity. In contrast, some studies report that drugs bound to alpha 1-acid glycoprotein (AAG) may have increased binding that is related to increased serum AAG concentration; however, this is not a consistent finding. Oxidative drug biotransformation is minimally changed in obesity with the exceptions of ibuprofen and prednisolone, for which clearance increases as a highly correlated function of total bodyweight. Drug conjugation uniformly increases as a function of bodyweight in obesity, with paracetamol (acetaminophen), lorazepam and oxazepam having been studied. Drug acetylation may be unchanged in obesity, with only procainamide evaluated at this time. High clearance drugs, including lignocaine, verapamil and midazolam, have no change in clearance in obese individuals compared to normal bodyweight controls. Renal clearance of drugs is little changed for some drugs evaluated (digoxin, cimetidine), and increased for others (aminoglycosides, unmetabolised procainamide). Characterisation of appropriate animal models of obesity is underway to clarify the mechanisms for these in vivo pharmacokinetic observations in obese man. Two models, the Zucker obese and the obese cafeteria-fed male Sprague-Dawley rat, have provided preliminary physiological pharmacokinetic data with evaluations of theophylline, phenobarbitone and verapamil.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Drug disposition in obese humans. An update. 352 55

The serum viscosity of diabetic patients has been found to be increased. The elevation averaged 8% above healthy subjects and 6% above nondiabetic patients. The serum viscosity elevation was greater when diabetic sequelae associated with microangiopathy were present. No relation of serum viscosity to age, sex, obesity, duration of disease, or type of treatment was demonstrated. Serum total protein and glucose levels were found to be correlated with serum viscosity, and increases in their serum concentrations were observed in diabetes. Analysis demonstrated that their elevation did not explain either the viscosity increase or the difference in viscosity between diabetics with and without sequelae.Intrinsic viscosity, abbreviated [eta], is a concentration-independent solute property related to molecular shape. [eta] was found to be 7% higher in diabetic than in normal serum. The [eta] difference accounted for at least half of the serum viscosity elevation. The rest of the increase was due to increased serum protein level and increased nonprotein solids, presumably glucose and lipid. Associated with increased [eta] was a decline in albumin: globulin ratio and elevation of the acute phase reactant proteins, alpha(1)-acid glycoprotein, alpha(1)-antitrypsin, haptoglobin, and ceruloplasmin. Studies comparing diabetic and normal serum fractionated by using 21.5% sodium sulfate showed that changes in [eta] were attributable to changes in serum protein composition rather than an inherent qualitative disturbance of protein present in one of the fractions. Since serum viscosity is elevated in early diabetes, it may be a part of the metabolic disturbance of diabetes and could play a role in the development of diabetic microangiopathy.
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PMID:Disturbance of serum viscosity in diabetes mellitus. 420 23

Serum protein and lipid concentrations as well as the serum protein binding of propranolol, diazepam and phenytoin were measured in normal weight and obese volunteers. Concentrations of alpha 1-acid glycoprotein (AAG) in the obese subjects were double that of the lean controls. Conversely, concentrations of high density lipoproteins (HDL) were decreased in the obese group. The serum binding of propranolol was increased in the obese subjects and correlated with serum AAG concentrations. Diazepam binding was slightly decreased in the obese as a result of lower serum albumin concentrations and elevated free fatty acids. The binding of phenytoin was comparable in all of the volunteers. These findings point out some of the complex pathophysiologic changes associated with obesity which may in turn influence drug disposition and hence drug therapy in the obese patient.
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PMID:Serum protein binding and the role of increased alpha 1-acid glycoprotein in moderately obese male subjects. 652 34

Although clinically relevant, drug-protein interactions in the morbidly obese population have not been studied thoroughly. The objective of this study was to evaluate serum chemistry profiles and the degree of serum protein binding of propranolol, diazepam and phenytoin in the serum of four female, morbidly obese (greater than 190% of ideal body weight) and eight control female subjects. Serum triglyceride concentrations were higher and high-density lipoproteins were lower in the obese subjects than in the control group. Serum albumin and total protein concentrations in the obese were not different from controls. Unexpectedly, alpha 1-acid glycoprotein concentrations were doubled in the obese subjects (mean obese value 121 mg/100 ml vs 62.9 mg/100 ml for the control subjects). Obese subjects had a mean fraction unbound (fu) for propranolol of 0.086, which was significantly different from the controls (fu = 0.123). The binding of diazepam was decreased slightly in the obese subjects. The binding of phenytoin was similar in both groups. The altered serum chemistry of obesity may play a significant role in the drug management of the obese patient by altering drug-protein interactions.
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PMID:Serum alpha 1-acid glycoprotein and the binding of drugs in obesity. 666 65


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