Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 mouse ob mutation has been mapped relative to a series of RFLPs among the progeny of three separate mouse crosses: an intraspecific backcross, an intraspecific intercross, and an interspecific intercross. Genotypic assignment at the ob locus was made by making use of measurements of body mass index and the plasma concentrations of glucose and insulin. These data have suggested that the development of diabetes in these animals is a consequence of unlinked polygenes. There was also evidence that unlinked Mus spretus alleles can diminish the obesity of ob/ob mice. From these data we have mapped several markers on chromosome 6 with the following order: cen-Cola-2-Met-ob-Cpa-Tcrb. The homologs of markers that flank ob map to human chromosome 7q, suggesting that if there is a human homologue of ob, it maps to 7q31.
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PMID:Molecular mapping of the mouse ob mutation. 168 14

With the combination of a noninvasive saturation measurement and plethysmography, pulse oximetry has become an important monitoring method for peripheral perfusion and oxygen supply. Indications for pulse oximetry is practically every anaesthesia especially in geriatric patients and patients with one-lung-anaesthesia, obesity, asthma and emphysema. Pulse oximetry has proved its worth in the transport of emergency patients. Sources of error are a bad perfusion at the site of measurement (hypotension, hypothermia), dyshaemoglobinaemia (Met-carboxy-haemoglobin) and interference of colours (dark skin, intravenous colours, high light intensity). Accuracy of response of most currently available pulse oximeters lies between 2-3% (SD) with oxygen saturations between 80-100%. Deviations increase at lower oxygen saturations. Pulse oximetry will soon be regarded as minimal monitoring standard worldwide together with the ECG, blood pressure, pulse and respiratory monitoring.
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PMID:[The importance of pulse oximetry for anesthesia]. 204 38

We have recently shown that in addition to beta-endorphin the opioid peptides Met- and Leu-enkephalin and their apparent precursors are localized in islet endocrine cells of the rat pancreas. To begin evaluating a possible role for these pancreatic opiates in the pathophysiology of genetic diabetes in rodents, immunoreactive beta-endorphin and Met- and Leu-enkephalins were measured in acetic acid extracts of pancreas and pituitary of C57BL/KsJ db/db mice and their lean littermates. Groups of animals were studied during three phases of development of the diabetic syndrome in the mutant mice: at 4 (hyperinsulinemic and prediabetic); 6, 9, and 12 (frankly obese and diabetic); and 30 (hypoinsulinemic) wk of age. Elevations or decreases (P less than .05) were found in db/db mice (vs. lean littermates) as follows: pituitary content of Met-enkephalin was twofold higher at all ages studied; pituitary free Leu-enkephalin was lower at 4 wk and reversed to higher at 6-30 wk; pancreatic beta-endorphin was 30% lower at 4 wk and reversed to threefold higher at 6-12 wk; Met- and Leu-enkephalin-containing larger peptides were elevated at one or more points between 6 and 12 wk in both the pancreas and the pituitary. Thus, the onset of overt obesity between 4 and 6 wk of age was accompanied by a marked rise in both pancreatic beta-endorphin and pituitary Leu-enkephalin; similar elevations in these parameters have been reported previously in C57BL/6J ob/ob mice at approximately 12 wk of age.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Altered beta-endorphin, Met- and Leu-enkephalins, and enkephalin-containing peptides in pancreas and pituitary of genetically obese diabetic (db/db) mice during development of diabetic syndrome. 294 83

Our objective was to investigate whether genetic variants of the uncoupling protein 1 (UCP1) gene are associated with juvenile-onset obesity or alterations in weight gain and insulin sensitivity in young healthy Caucasians. Single-strand conformation polymorphism and heteroduplex analysis of the coding region of the UCP1 gene was performed in 56 subjects randomly selected at the draft board examination from a cohort of 156 males with juvenile-onset obesity. Association studies of amino acid variants were undertaken in the cohort of males with juvenile-onset obesity, a cohort of 205 randomly selected control males, and a subgroup of this cohort comprising 76 lean subjects. Genetic variants of the coding region as well as a previously described a-->g nucleotide polymorphism of the 5'-flanking region of the UCP1 gene were examined for associations with accelerated weight gain or reduced sensitivity to insulin in a cohort of 380 young healthy Caucasians. The mutational analysis revealed five nucleotide substitutions that changed the sequence of UCP1, Arg/Trp40, Ala/Thr64, Val/Met137, Met/Leu229, and Lys/Asn257 and two nucleotide substitutions in the nontranslated region of exon 1. Among subjects with juvenile-onset obesity, the allelic frequencies of Ala/Thr64 and Met/Leu229 were both 8.2% (95% confidence interval: 5.1-11.3%) vs. 8.8% (6.0-11.6%) and 8.1% (5.3-10.9%), respectively, in the cohort of randomly selected control subjects. Among lean control subjects, the allelic frequencies of the polymorphisms were 8.2% (3.7-12.7%) and 5.6% (1.9-9.3%), respectively. In the cohort of young healthy subjects, measurements of obesity and insulin sensitivity did not differ between carriers of the Ala/Thr64 and Met/Leu229 variants and wild-type carriers. The Val/Met137 and Lys/Asn257 mutations were each found in one subject with juvenile-onset obesity, and the Arg/Trp40 mutation was found in two obese subjects and in one control subject. The allelic frequency of the nucleotide polymorphism of the 5'-flanking region of the UCP1 gene was 25.3% (22.2-28.4%) in the cohort of 380 young Danes. There were no differences in body mass index, fat mass, waist-to-hip ratio, or weight gain during childhood or adolescence between carriers and noncarriers of this nucleotide variant. Although we cannot exclude an effect of the rare mutations in the UCP1 gene on susceptibility to juvenile-onset obesity, genetic variation of the coding region of the UCP1 gene is not a common factor contributing to obesity in Caucasian subjects of Danish ancestry.
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PMID:Studies of genetic variability of the uncoupling protein 1 gene in Caucasian subjects with juvenile-onset obesity. 939 15

Melanocortins, which are involved in melanocyte pigmentation control and glucocorticoid stimulation, have functional roles in various physiological mechanisms and have been shown to participate in higher cortical functions. Recently, it has also been reported that melanocyte-stimulating hormone (MSH) and melanocortin 4 receptor (MC4R) are the key components of the hypothalamic response to obesity. The solution structures of both melanocyte-stimulating hormone alpha-MSH (Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2) and its analog alpha-MSH-ND (Ac-Ahx-Asp-His-DPhe-Arg-Trp-Lys-NH2) (Ahx, 2-aminohexanoic acid) have been determined by two-dimensional NMR spectroscopy and simulated-annealing calculations. The NMR data revealed that alpha-MSH forms a hairpin loop conformation which includes conserved message sequences, whereas alpha-MSH-ND prefers a type I beta-turn comprising residues of Asp2-His3-DPhe4-Arg5. Final simulated-annealing structures of both alpha-MSH-ND and alpha-MSH peptides converged with rmsd of 0.07 nm for alpha-MSH-ND and 0.1 nm for alpha-MSH between backbone atoms, respectively. This result will provide the structural bases of melanocortin functions as well as valuable information for structure-based drug design involving the regulation of obesity and feeding.
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PMID:Solution structures of the melanocyte-stimulating hormones by two-dimensional NMR spectroscopy and dynamical simulated-annealing calculations. 979 99

The melanocortin-4 receptor gene (MC4-R) has been implicated in weight regulation. Recently, two independent groups reported frameshift mutations associated with a dominant form of obesity (1, 2). We screened the coding region of the MC4-R in 306 extremely obese children and adolescents (mean body mass index: BMI 34.4 +/- 6.6 kg/m2), 25 healthy underweight students (mean BMI 17.1 +/- 0.8 kg/m2), 52 normal weight individuals (mean BMI 22.0 +/- 1.0 kg/m2), 51 inpatients with anorexia nervosa (AN, DSM IV criteria, mean BMI 14.3 +/- 1.5 kg/m2) and 27 patients with bulimia nervosa (BN, DSM IV criteria, mean BMI 21.7 +/- 5.8 kg/m2) by single strand conformation polymorphism analysis (SSCP). Several mutations were identified, including the frameshift mutation described (1). The mutations were as follows: a) The deletion of 4 bp (delta of CTCT at codon 211) results in a frameshift, thus rendering a truncated protein. This mutation has been assumed to be associated with dominantly-inherited morbid obesity in humans (1). Both the index patient (BMI 42.06 kg/m2, height 171 cm, age 19.6 years) and her mother (BMI 37.55 kg/m2, height 164 cm, age 42.5 years) were heterozygous for the deletion. b) A nonsense mutation at position 35 of the MC4-R was detected in two obese probands (BMI 31.29 kg/m2 and BMI 45.91 kg/m2). This mutation leads to a truncated protein that encompasses the N-terminal extracellular domain. Both carriers additionally showed (c) a missense mutation (Asp-37-Val). In both of these cases Tyr-35-Stop and Asp-37-Val were maternally transmitted, thus these variations form a haplotype. d) e) A male obese proband harbored two missense mutations (Ser-30-Phe, Gly-252-Ser). f)-i) Four different missense mutations (Pro-78-Leu, Thr-112-Met, Arg-165-Trp, Ile-317-Thr) were detected in four different male probands, respectively. All of these mutations (a to i) were found solely in extremely obese individuals whose BMIs were all above the 99th percentile. j) A silent mutation (C-579-T, Val-193-Val) was detected in a male underweight individual. k) A previously described polymorphism (Val-103-Ile; 3) was detected with similar frequencies in all different study groups. 1) We identified a novel polymorphism (Ile-251-Leu) with similar allele frequencies in all groups under study. In conclusion, our data indicate that mutations in the MC4-R are not uncommon. Whereas our data support the evidence for dominantly inherited obesity as revealed by the three obese probands with haplo-insufficiency, the functional significance of the missense mutations remains to be determined.
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PMID:Several mutations in the melanocortin-4 receptor gene including a nonsense and a frameshift mutation associated with dominantly inherited obesity in humans. 1019

Even among young, healthy individuals, there is more than a 10-fold variation in insulin sensitivity; however, taken in combination, all the known modifiers of insulin sensitivity - including obesity and a variety of environmental factors - explain less than one third of this variation. It is possible that genetic factors could account for the bulk of the variance observed, and hence play a major role in the development of impaired insulin sensitivity, ie insulin resistance. From the genetic point of view, insulin resistance is thought to be due to the inheritance of a number of mutations in a variety of genes. Three complementary approaches have been applied in the search for mutations: mutational analysis of candidate genes; linkage analysis of candidate genes or chromosomal regions for insulin resistance in familial type 2 diabetes; and random genome mapping with quantitative trait loci (QTL) analysis. Mutational analysis of the insulin signalling cascade has identified a glycine-arginine (Gly-Arg) substitution at codon 972 of the insulin receptor substrate-1 (IRS-1) gene with a carrier prevalence of 9% among Caucasians. Expression of this variant in 32-D cells is associated with a significant (20-30%) impairment of insulin-stimulated PI3-kinase activity, as well as reduced binding of IRS-1 to the p85 regulatory subunit of PI3-kinase. Genotype/phenotype studies stratified according to body mass index (BMI) indicate that obese subjects who are heterozygous for the mutant allele have a 50% decrease in insulin sensitivity, compared with wild-type obese subjects. This suggests that there may be an interaction between the mutant allele and obesity, such that, in the presence of obesity, the mutant variant may aggravate the obesity-associated insulin resistance. Mutational analysis has also shown that homozygous carriers of a codon Met 326 Ile mutation in the p85 subunit of phosphatidylinositol-3 (PI3)-kinase (about 2% of the Caucasian population) have lower glucose tolerance, glucose effectiveness. A further Asp to Tyr polymorphism has been identified at codon 905 of the gene encoding the regulatory subunit of glycogen-associated protein phosphatase-1 (PP1G). Individuals who are heterozygous for this polymorphism constitute 18% of the Caucasian population and appear to exhibit both tissue-specific and pathway-specific insulin resistance. It is likely that inherited insulin resistance will eventually prove to be related to subtle mutations in many such genes of the insulin signalling network and the numerous genetic components controlling energy metabolism.
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PMID:Genetics of insulin resistance. 1032 50

A simple and convenient high performance liquid chromatographic method with UV detection is described for the determination of mazindol [5-(p-chlorophenyl)-2,5-dihydro-3H-imidazo[2,1-a]isoindol-5-ol] and its major metabolite, 2-(2-aminoethyl)-3-(p-chlorophenyl)-3-hydroxyphthalimidine (Met), in human plasma. The analytes were extracted with ethyl acetate from plasma samples and separated on a C18 column using acetonitrile-0.067 mol dm(-3) phosphate buffer (pH 3.5) (24 + 76 v/v) as a mobile phase. The eluates were monitored at 220 nm. Following complete validation and stability studies, the proposed method proved to be sensitive and precise. The limits of detection were 0.07 and 0.08 ng ml(-1) of plasma for mazindol and Met, respectively. The accuracy and recovery were in the ranges 94-102% and 91-102%, respectively, for both compounds. The intra- and inter-assay precisions were less than 7.6 and 9.2%, respectively, for both compounds. The stability of mazindol under different storage conditions, i.e., at room temperature (rt) and 4 degrees C and with freeze-thaw cycles, was also examined. Mazindol was unstable in plasma samples left at rt and 4 degrees C. The method was applied to the determination of mazindol and Met in the plasma of a patient treated for obesity with mazindol.
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PMID:High performance liquid chromatographic determination of mazindol in human plasma. 1176 75

Ghrelin induces obesity via central and peripheral mechanisms. Administration of ghrelin leads to increased food intake and decreased fat utilisation in rodents. Ghrelin levels are decreased in obese individuals. Recently, a polymorphism (Arg-51-Gln) within the ghrelin gene (GHRL) was described to be associated with obesity. We screened the GHRL coding region in 215 extremely obese German Children and adolescents (study group 1) and 93 normal weight students (study group 2) by single strand conformation polymorphism analysis (SSCP). We found the two previously described single nucleotide polymorphisms (SNP: Arg-51-Gln and Leu-72-Met) in similar frequencies in study groups 1 and 2 (allele frequencies were: 0.019 and 0.016 for the 51-Gln allele and 0.091 and 0.086 for the 72-Met allele, respectively). Hence, we could not confirm the previous finding. Additionally, two novel variants were identified within the coding region: (1) We detected one healthy normal weight individual with a frameshift mutation (2bp deletion at codon 34). This frameshift mutation affects the coding region of the mature ghrelin. Hence, it is highly likely that the normal weight student is haplo-insufficient for ghrelin. (2) An A to T transversion leads to an amino acid exchange from Gln to Leu at amino acid position 90. The frequency of the 90-Leu allele was significantly higher in the extremely obese children and adolescents (0.063) than in the normal weight students (0.016; nominal p = 0.011). Additionally, we genotyped 134 underweight students and 44 normal weight adults for this SNP. Genotype frequencies were similar in extremely obese children and adolescents, underweight students and normal weight adults (p > 0.8). In conclusion, we identified four sequence variants in the coding region of the ghrelin gene in individuals belonging to different weight extremes. A frameshift mutation was detected in a normal weight individual. None of the variants seem to influence weight regulation.
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PMID:Ghrelin gene: identification of missense variants and a frameshift mutation in extremely obese children and adolescents and healthy normal weight students. 1205 Feb 39

Carnitine acyltransferases catalyze the exchange of acyl groups between coenzyme A (CoA) and carnitine. They have important roles in many cellular processes, especially the oxidation of long-chain fatty acids, and are attractive targets for drug discovery against diabetes and obesity. These enzymes are classified based on their substrate selectivity for short-chain, medium-chain, or long-chain fatty acids. Structural information on carnitine acetyltransferase suggests that residues Met-564 and Phe-565 may be important determinants of substrate selectivity with the side chain of Met-564 located in the putative binding pocket for acyl groups. Both residues are replaced by glycine in carnitine palmitoyltransferases. To assess the functional relevance of this structural observation, we have replaced these two residues with small amino acids by mutagenesis, characterized the substrate preference of the mutants, and determined the crystal structures of two of these mutants. Kinetic studies confirm that the M564G or M564A mutation is sufficient to increase the activity of the enzyme toward medium-chain substrates with hexanoyl-CoA being the preferred substrate for the M564G mutant. The crystal structures of the M564G mutant, both alone and in complex with carnitine, reveal a deep binding pocket that can accommodate the larger acyl group. We have determined the crystal structure of the F565A mutant in a ternary complex with both the carnitine and CoA substrates at a 1.8-A resolution. The F565A mutation has minor effects on the structure or the substrate preference of the enzyme.
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PMID:Structural and biochemical studies of the substrate selectivity of carnitine acetyltransferase. 1515 26


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