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Hobbs FDR, Kenkre JE, Roalfe AK, Davis RC, Hare R, Davies MK. Impact of heart failure and left ventricular systolic dysfunction on quality of life: a cross-sectional study comparing common chronic cardiac and medical disorders and a representative adult population. Eur Heart J 2002; 23:1867-76. [PMID: 12445536 DOI: 10.1053/euhj.2002.3255] [Citation(s) in RCA: 304] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Heart failure and left ventricular systolic dysfunction (LVSD) are increasingly common disorders, with outcomes worse than many cancers. Evidence-based therapies, such as ACE inhibitors and beta-blockers, improve prognosis and symptoms, and reduce healthcare expenditure. However, despite the high prevalence and malignant prognosis, few studies have reported the impact of heart failure and LVSD on overall quality of life and, more crucially, have not researched the elderly or those in the community. METHODS All patients attending the Echocardiographic Heart of England Screening (ECHOES) study of the prevalence of heart failure and LVSD in the community were assessed by clinical history and examination, electrocardiogram and echocardiography, and also completed the SF36 health status questionnaire. Quality of life in patients found to have heart failure, LVSD, and other cardiac and medical conditions are compared with the randomly selected general population sample. Data are generalisable to the UK. RESULTS 6162 people in the community were screened in the ECHOES study, of whom 5961 (97%) completed the SF36. The health perceptions of 3850 people aged 45 years or older selected randomly from the population were compared with those of 426 patients diagnosed as having definite heart failure. Those with heart failure had significant impairment of all the measured aspects of physical and mental health, in addition to declines in physical functioning. Significantly worse impairment was found in those with more severe heart failure by NYHA class: indeed, NYHA functional class was closely correlated to SF36 score. Patients with asymptomatic left ventricular dysfunction and patients rendered asymptomatic by treatment had similar scores to the random population sample. Those with heart failure reported more severe physical impairment of quality of life than people giving a history of chronic lung disease or arthritis, with less impact on mental health than patients reporting depression. CONCLUSIONS Patients with heart failure have statistically significant impairment of all aspects of quality of life, not simply physical functioning. The physical (role and functioning) health burden was significantly greater than that suffered in other serious common chronic disorders, whether cardiac or other systems. Optimising treatment to improve NYHA class appears to improve perceptions of quality of life for patients with heart failure. Given the dramatic decline in quality of life with heart failure, this end-point should be a much more important target for healthcare interventions, especially treatments such as ACE inhibitors and beta-blockers that are shown to improve quality of life.
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Multicenter Study |
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304 |
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Hobbs FDR, Davis RC, Roalfe AK, Hare R, Davies MK, Kenkre JE. Reliability of N-terminal pro-brain natriuretic peptide assay in diagnosis of heart failure: cohort study in representative and high risk community populations. BMJ 2002; 324:1498. [PMID: 12077039 PMCID: PMC116449 DOI: 10.1136/bmj.324.7352.1498] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To investigate the performance of a novel assay for N-terminal pro-brain natriuretic peptide (NT-proBNP) in diagnosing heart failure in various randomly selected general and high risk community populations. DESIGN Community cohort study (substudy of the echocardiographic heart of England screening study). SETTING Four randomly selected general practices in the West Midlands of England. PARTICIPANTS 591 randomly sampled patients over the age of 45, stratified for age and socioeconomic status and falling into four cohorts (general population, patients with an existing clinical label of heart failure, patients prescribed diuretics, and patients deemed at high risk of heart failure). MAIN OUTCOME MEASURE Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and area under receiver operating characteristic curve for NT-proBNP assay in the diagnosis of heart failure. RESULTS For NT-proBNP in the diagnosis of heart failure in the general population (population screen), a level of >36 pmol/l had a sensitivity of 100%, a specificity of 70%, a positive predictive value of 7%, a negative predictive value of 100%, and an area under the receiver operating characteristic curve of 0.92 (95% confidence interval 0.82 to 1.0). Similar negative predictive values were found for patients from the three other populations screened. CONCLUSIONS This NT-proBNP assay seems to have value in the diagnosis of heart failure in the community. High negative predictive values indicate that the assay's chief use would be to rule out heart failure in patients with suspected heart failure with normal concentrations of NT-proBNP. Positive results may identify patients who need cardiac imaging.
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Clinical Trial |
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147 |
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Bamburg JR, Bernstein BW, Davis RC, Flynn KC, Goldsbury C, Jensen JR, Maloney MT, Marsden IT, Minamide LS, Pak CW, Shaw AE, Whiteman I, Wiggan O. ADF/Cofilin-actin rods in neurodegenerative diseases. Curr Alzheimer Res 2010; 7:241-50. [PMID: 20088812 PMCID: PMC4458070 DOI: 10.2174/156720510791050902] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 11/24/2009] [Indexed: 11/22/2022]
Abstract
Dephosphorylation (activation) of cofilin, an actin binding protein, is stimulated by initiators of neuronal dysfunction and degeneration including oxidative stress, excitotoxic glutamate, ischemia, and soluble forms of beta-amyloid peptide (Abeta). Hyperactive cofilin forms rod-shaped cofilin-saturated actin filament bundles (rods). Other proteins are recruited to rods but are not necessary for rod formation. Neuronal cytoplasmic rods accumulate within neurites where they disrupt synaptic function and are a likely cause of synaptic loss without neuronal loss, as occurs early in dementias. Different rod-inducing stimuli target distinct neuronal populations within the hippocampus. Rods form rapidly, often in tandem arrays, in response to stress. They accumulate phosphorylated tau that immunostains for epitopes present in "striated neuropil threads," characteristic of tau pathology in Alzheimer disease (AD) brain. Thus, rods might aid in further tau modifications or assembly into paired helical filaments, the major component of neurofibrillary tangles (NFTs). Rods can occlude neurites and block vesicle transport. Some rod-inducing treatments cause an increase in secreted Abeta. Thus rods may mediate the loss of synapses, production of excess Abeta, and formation of NFTs, all of the pathological hallmarks of AD. Cofilin-actin rods also form within the nucleus of heat-shocked neurons and are cleared from cells expressing wild type huntingtin protein but not in cells expressing mutant or silenced huntingtin, suggesting a role for nuclear rods in Huntington disease (HD). As an early event in the neurodegenerative cascade, rod formation is an ideal target for therapeutic intervention that might be useful in treatment of many different neurological diseases.
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Research Support, N.I.H., Extramural |
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135 |
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Osterlund T, Danielsson B, Degerman E, Contreras JA, Edgren G, Davis RC, Schotz MC, Holm C. Domain-structure analysis of recombinant rat hormone-sensitive lipase. Biochem J 1996; 319 ( Pt 2):411-20. [PMID: 8912675 PMCID: PMC1217784 DOI: 10.1042/bj3190411] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hormone-sensitive lipase (HSL) plays a key role in lipid metabolism and overall energy homoeostasis, by controlling the release of fatty acids from stored triglycerides in adipose tissue. Lipases and esterases form a protein superfamily with a common structural fold, called the alpha/beta-hydrolase fold, and a catalytic triad of serine, aspartic or glutamic acid and histidine. Previous alignments between HSL and lipase 2 of Moraxella TA144 have been extended to cover a much larger part of the HSL sequence. From these extended alignments, possible sites for the catalytic triad and alpha/beta-hydrolase fold are suggested. Furthermore, it is proposed that HSL contains a structural domain with catalytic capacity and a regulatory module attached, as well as a structural N-terminal domain unique to this enzyme. In order to test the proposed domain structure, rat HSL was overexpressed and purified to homogeneity using a baculovirus/insect-cell expression system. The purification, resulting in > 99% purity, involved detergent solubilization followed by anion-exchange chromatography and hydrophobic-interaction chromatography. The purified recombinant enzyme was identical to rat adipose-tissue HSL with regard to specific activity, substrate specificity and ability to serve as a substrate for cAMP-dependent protein kinase. The recombinant HSL was subjected to denaturation by guanidine hydrochloride and limited proteolysis. These treatments resulted in more extensive loss of activity against phospholipid-stabilized lipid substrates than against water-soluble substrates, suggesting that the hydrolytic activity can be separated from recognition of lipid substrates. These data support the concept that HSL has at least two major domains.
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research-article |
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119 |
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57 |
119 |
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Mehrabian M, Wen PZ, Fisler J, Davis RC, Lusis AJ. Genetic loci controlling body fat, lipoprotein metabolism, and insulin levels in a multifactorial mouse model. J Clin Invest 1998; 101:2485-96. [PMID: 9616220 PMCID: PMC508838 DOI: 10.1172/jci1748] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We analyzed the inheritance of body fat, leptin levels, plasma lipoprotein levels, insulin levels, and related traits in an intercross between inbred mouse strains CAST/Ei and C57BL/6J. CAST/Ei mice are unusually lean, with only approximately 8% of body weight as fat, whereas C57BL/6J mice have approximately 18% body fat. Quantitative trait locus analysis using > 200 F2 mice revealed highly significant loci (lod scores > 4.3) on chromosomes 2 (three separate loci) and 9 that contribute to mouse fat-pad mass for mice on a high-fat diet. Some loci also influenced plasma lipoprotein levels and insulin levels either on chow or high-fat diets. Two loci for body fat and lipoprotein levels (on central and distal chromosome 2) coincided with a locus having strong effects on hepatic lipase activity, an activity associated with visceral obesity and lipoprotein levels in humans. A locus contributing to plasma leptin levels (lod score 5.3) but not obesity was identified on chromosome 4, near the leptin receptor gene. These data identify candidate regions and candidate genes for studies of human obesity and diabetes, and suggest obesity is highly complex in terms of the number of genetic factors involved. Finally, they support the existence of specific genetic interactions between body fat, insulin metabolism, and lipoprotein metabolism.
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research-article |
27 |
106 |
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Davis RC, Hobbs FD, Lip GY. ABC of heart failure. History and epidemiology. BMJ (CLINICAL RESEARCH ED.) 2000; 320:39-42. [PMID: 10617530 PMCID: PMC1117316 DOI: 10.1136/bmj.320.7226.39] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Historical Article |
25 |
100 |
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53 |
94 |
9
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Aouizerat BE, Allayee H, Cantor RM, Davis RC, Lanning CD, Wen PZ, Dallinga-Thie GM, de Bruin TW, Rotter JI, Lusis AJ. A genome scan for familial combined hyperlipidemia reveals evidence of linkage with a locus on chromosome 11. Am J Hum Genet 1999; 65:397-412. [PMID: 10417282 PMCID: PMC1377938 DOI: 10.1086/302490] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Familial combined hyperlipidemia (FCHL) is a common familial lipid disorder characterized by a variable pattern of elevated levels of plasma cholesterol and/or triglycerides. It is present in 10%-20% of patients with premature coronary heart disease. The genetic etiology of the disease, including the number of genes involved and the magnitude of their effects, is unknown. Using a subset of 35 Dutch families ascertained for FCHL, we screened the genome, with a panel of 399 genetic markers, for chromosomal regions linked to genes contributing to FCHL. The results were analyzed by use of parametric-linkage methods in a two-stage study design. Four loci, on chromosomes 2p, 11p, 16q, and 19q, exhibited suggestive evidence for linkage with FCHL (LOD scores of 1.3-2.6). Markers within each of these regions were then examined in the original sample and in additional Dutch families with FCHL. The locus on chromosome 2 failed to show evidence for linkage, and the loci on chromosome 16q and 19q yielded only equivocal or suggestive evidence for linkage. However, one locus, near marker D11S1324 on the short arm of human chromosome 11, continued to show evidence for linkage with FCHL, in the second stage of this design. This region does not contain any strong candidate genes. These results provide evidence for a candidate chromosomal region for FCHL and support the concept that FCHL is complex and heterogeneous.
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research-article |
26 |
92 |
10
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Schoenfield LJ, Berci G, Carnovale RL, Casarella W, Caslowitz P, Chumley D, Davis RC, Gillenwater JY, Johnson AC, Jones RS. The effect of ursodiol on the efficacy and safety of extracorporeal shock-wave lithotripsy of gallstones. The Dornier National Biliary Lithotripsy Study. N Engl J Med 1990; 323:1239-45. [PMID: 2215608 DOI: 10.1056/nejm199011013231804] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND In the treatment of gallstones with extracorporeal shock-wave lithotripsy, the bile acid ursodiol is administered to dissolve the gallstone fragments. We designed our study to determine the value of administering this agent. METHODS At 10 centers, 600 symptomatic patients with three or fewer radiolucent gallstones 5 to 30 mm in diameter, as visualized by oral cholecystography, were randomly assigned to receive ursodiol or placebo for six months, starting one week before lithotripsy. RESULTS The stones were fragmented in 97 percent of all patients, and the fragments were less than or equal to 5 mm in diameter in 46.8 percent. On the basis of an intention-to-treat analysis of all 600 patients, 21 percent receiving ursodiol and 9 percent receiving placebo (P less than 0.0001) had gallbladders that were free of stones after six months. Among those with completely radiolucent solitary stones less than 20 mm in diameter, 35 percent of the patients receiving ursodiol and 18 percent of those receiving placebo (P less than 0.001) were free of stones after six months. Biliary pain, usually mild, occurred in 73 percent of all patients but in only 13 percent of those who were free of stones after three and six months (P less than 0.01). There were few adverse events. Only diarrhea occurred with a significantly different frequency in the two groups: 32.6 percent were affected in the ursodiol group, as compared with 24.7 percent in the placebo group (P less than 0.04). Severe biliary pain occurred in 1.5 percent of all patients, acute cholecystitis in 1.0 percent, and acute pancreatitis in 1.5 percent; endoscopic sphincterotomy was performed in 0.5 percent, and cholecystectomy in 2.5 percent. CONCLUSIONS Extracorporeal shock-wave lithotripsy with ursodiol was more effective than lithotripsy alone for the treatment of symptomatic gallstones, and equally safe. Treatment was more effective for solitary than multiple stones, radiolucent than slightly calcified stones, and smaller than larger stones.
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Clinical Trial |
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Kleinfeld AM, Prothro D, Brown DL, Davis RC, Richieri GV, DeMaria A. Increases in serum unbound free fatty acid levels following coronary angioplasty. Am J Cardiol 1996; 78:1350-4. [PMID: 8970405 DOI: 10.1016/s0002-9149(96)00651-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Serum unbound free fatty acid levels (FFAu) were measured in patients undergoing percutaneous transluminal coronary angioplasty (PTCA) using the fluorescent probe acrylodan intestinal fatty acid binding protein (ADIFAB). These are the first measurements of FFAu, under nonphysiologic conditions. In these studies, FFAu, levels were determined in 22 patients 5 minutes before and 30 minutes after the procedure. Post-PTCA FFAu, levels were higher than pre-PTCA levels in all patients. The average post-PTCA level for all patients was 103 nM, about 14-fold higher than the 7.5 nM value observed in healthy subjects. Although all patients exhibited elevated FFAu levels after PTCA, ischemic ST-segment changes were observed in only 11 of these patients. The average post-PTCA FFAu levels for patients with significant ST-segment changes (123 nM) were significantly higher than those in patients who did not exhibit such changes (47 nM). Average FFAu (22 nM) levels before the procedure were elevated in the patient population relative to healthy subjects and these values correlated positively with post-PTCA levels. These results suggest that increased serum FFAu levels reflect angioplasty-induced ischemia and that FFAu levels may provide a more sensitive measure of ischemia than electrocardiographic measurements. Moreover, because 30% of these patients had post-PTCA FFAu concentrations exceeding those found to alter in vitro cell function, the increased serum FFAu levels that accompany ischemia may be deleterious for myocardial function.
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29 |
72 |
12
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Wong H, Davis RC, Nikazy J, Seebart KE, Schotz MC. Domain exchange: characterization of a chimeric lipase of hepatic lipase and lipoprotein lipase. Proc Natl Acad Sci U S A 1991; 88:11290-4. [PMID: 1763042 PMCID: PMC53120 DOI: 10.1073/pnas.88.24.11290] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Hepatic lipase and lipoprotein lipase hydrolyze fatty acids from triacylglycerols and are critical in the metabolism of circulating lipoproteins. The two lipases are similar in size and amino acid sequence but are distinguished by functional differences in substrate preference and cofactor requirement. Presumably, these distinctions result from structural differences in functional domains. To begin localization of these domains, a chimeric lipase was constructed composed of the N-terminal 329 residues of rat hepatic lipase linked to the C-terminal 136 residues of human lipoprotein lipase. The chimera hydrolyzed both monodisperse short-chain (esterase) and emulsified long-chain (lipase) triacylglycerol substrates with catalytic and kinetic properties closely resembling those of native hepatic lipase. However, monoclonal antibodies to lipoprotein lipase inhibited the lipase activity, but not the esterase function, of the chimera. Therefore, the chimeric molecule is a functional lipase and contains elements and characteristics from both parental enzymes. It is proposed that the N-terminal domain, containing the active center from hepatic lipase, governs the catalytic character of the chimera, and the C-terminal domain is essential for hydrolysis of long-chain substrates.
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research-article |
34 |
67 |
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Barkin JS, Ferstenberg RM, Panullo W, Manten HD, Davis RC. Endoscopic retrograde cholangiopancreatography in pancreatic trauma. Gastrointest Endosc 2001; 34:102-5. [PMID: 2452762 DOI: 10.1016/s0016-5107(88)71272-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The sensitivity and specificity of ERCP for the diagnosis of suspected pancreatic ductal rupture was prospectively studied. Fourteen consecutive patients who were referred for abdominal pain and hyperamylasemia subsequent to abdominal trauma underwent ERCP, the majority within 24 hours of admission. Twelve of these also underwent abdominal CT, and 7 had peritoneal lavage. Four patients were found to have ductal rupture at ERCP. This was confirmed at laparotomy. Three additional patients who underwent laparotomy were found not to have a ductal rupture, although one had a pancreatic capsular laceration. The remaining 7 had clinical resolution. ERCP was 100% sensitive and specific in the diagnosis of pancreatic ductal rupture, whereas no combination of serum amylase, CT scan, and peritoneal lavage was equally effective.
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Comparative Study |
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66 |
14
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Cheng LS, Davis RC, Raffel LJ, Xiang AH, Wang N, Quiñones M, Wen PZ, Toscano E, Diaz J, Pressman S, Henderson PC, Azen SP, Hsueh WA, Buchanan TA, Rotter JI. Coincident linkage of fasting plasma insulin and blood pressure to chromosome 7q in hypertensive hispanic families. Circulation 2001; 104:1255-60. [PMID: 11551876 DOI: 10.1161/hc3601.096729] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Insulin resistance (IR) and hyperinsulinemia are phenotypically associated with hypertension. We have previously provided evidence that blood pressure (BP) and IR cosegregate in Hispanic families, suggesting that this association has a genetic component. In the present study, we provide further support for the hypothesis of a genetic basis for the BP-IR relationship from a genetic linkage study. METHODS AND RESULTS A 10-cM genome scan was conducted in 390 Hispanic family members of 77 hypertensive probands. Detailed measurements of BP, glucose, insulin levels, and insulin sensitivity (euglycemic clamp) were performed in adult offspring of probands. Multipoint variance component linkage analysis was used. A region on chromosome 7q seemed to influence both IR and BP. The greatest evidence for linkage was found for fasting insulin (lod score=3.36 at 128 cM), followed by systolic BP (lod score=2.06 at 120 cM). Fine mapping with greater marker density in this region increased the maximum lod score for fasting insulin to 3.94 at 125 cM (P=0.00002); lod score for systolic BP was 2.51 at 112 cM. Coincident mapping at this locus also included insulin sensitivity measured by the homeostasis assessment model (HOMA) and serum leptin concentrations. Insulin sensitivity by euglycemic clamp did not map to the same locus. CONCLUSIONS Our results demonstrate that a major gene determining fasting insulin is located on chromosome 7q. Linkage of BP, HOMA, and leptin levels to the same region suggests this locus may broadly influence traits associated with IR and supports a genetic basis for phenotypic associations in IR syndrome.
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64 |
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Wong H, Yang D, Hill JS, Davis RC, Nikazy J, Schotz MC. A molecular biology-based approach to resolve the subunit orientation of lipoprotein lipase. Proc Natl Acad Sci U S A 1997; 94:5594-8. [PMID: 9159117 PMCID: PMC20823 DOI: 10.1073/pnas.94.11.5594] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/1996] [Accepted: 03/26/1997] [Indexed: 02/04/2023] Open
Abstract
The subunit orientation of a dimeric enzyme influences the mechanism of action and function. To determine the subunit arrangement of lipoprotein lipase (LPL), a molecular biology-based approach was initiated. An eight amino acid linker region was engineered between two LPL monomers and expressed in COS-7 cells. The resultant tandem-repeat molecule (LPLTR) was lipolytically active and had kinetic parameters, salt inhibition, cofactor-dependent activity, heparin-binding characteristics, and a functional unit size very similar to the expressed native human enzyme. By these criteria, LPLTR was the functional equivalent of native LPL. Considering the length of the linker peptide (no more than 24 A), monomers in the tethered molecule were restricted to a head-to-tail subunit arrangement. Since LPLTR demonstrated native enzyme-like properties while constrained to this subunit arrangement, these results provide the first compelling evidence that native LPL monomers are arranged in a head-to-tail subunit orientation within the active dimer. Thus, LPL function in physiology, lipolysis, and binding to cell-surface components must now be addressed with this subunit orientation in mind. The utility of the tandem-repeat approach to resolve the subunit arrangement of an obligate dimer has been demonstrated with LPL and could be generalized for use with other oligomeric enzymes.
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research-article |
28 |
62 |
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Ameis D, Kobayashi J, Davis RC, Ben-Zeev O, Malloy MJ, Kane JP, Lee G, Wong H, Havel RJ, Schotz MC. Familial chylomicronemia (type I hyperlipoproteinemia) due to a single missense mutation in the lipoprotein lipase gene. J Clin Invest 1991; 87:1165-70. [PMID: 2010533 PMCID: PMC295125 DOI: 10.1172/jci115114] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Complete deficiency of lipoprotein lipase (LPL) causes the chylomicronemia syndrome. To understand the molecular basis of LPL deficiency, two siblings with drastically reduced postheparin plasma lipolytic activities were selected for analysis of their LPL gene. We used the polymerase chain reaction to examine the nine coding LPL exons in the two affected siblings and three relatives. DNA sequence analysis revealed a single nucleotide change compared with the normal LPL cDNA: a G----A substitution at nucleotide position 680. This transition caused a replacement of glutamic acid for glycine at amino acid residue 142 of the mature LPL protein. Amino acid sequence comparisons of the region surrounding glycine-142 indicated that it is highly conserved among lipases from different species, suggesting a crucial role of this domain for the LPL structure. Expression studies of the mutant LPL cDNA in COS-7 cells produced normal amounts of enzyme mass. However, the mutated LPL was not catalytically active, nor was it efficiently secreted from the cells. This established that the Gly----Glu substitution at amino acid 142 is sufficient to abolish enzymatic activity and to result in the chylomicronemia syndrome observed in these patients.
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research-article |
34 |
56 |
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Hollenberg M, Zoltick JM, Go M, Yaney SF, Daniels W, Davis RC, Bedynek JL. Comparison of a quantitative treadmill exercise score with standard electrocardiographic criteria in screening asymptomatic young men for coronary artery disease. N Engl J Med 1985; 313:600-6. [PMID: 4022047 DOI: 10.1056/nejm198509053131003] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A computer-derived treadmill exercise score that quantifies the electrocardiographic response to exercise has been reported to have a high sensitivity (87 per cent) and specificity (92 per cent) in patients with a high prevalence of coronary artery disease. To test its accuracy in young, asymptomatic men with a low prevalence of coronary artery disease, we evaluated the responses of 377 military officers (mean age, 36.6 years) by two independent methods. According to standard electrocardiographic criteria, 45 of the subjects (12 per cent) had positive tests, whereas the treadmill exercise score indicated that only 3 (less than 1 per cent) had positive tests. Since two of these three had left ventricular hypertrophy and met only the criteria for the latter without associated coronary artery disease, the treadmill exercise score predicted that only 1 of 377 subjects would have clinically important coronary artery disease. Coronary arteriography, performed in 10 persons with the most positive scores on standard treadmill tests and the highest scores for risk factors, showed that nine subjects did not have coronary artery disease and that one had single-vessel disease (the same subject who the treadmill score predicted would have mild disease). The treadmill exercise score appears to improve the diagnostic specificity of exercise electrocardiography and may be more useful than values on standard stress tests in screening asymptomatic populations for coronary artery disease.
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Comparative Study |
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Weissbach H, Redfield B, Yamasaki E, Davis RC, Pestka S, Brot N. Studies on the ribosomal sites involved in factors Tu and G-dependent reactions. Arch Biochem Biophys 1972; 149:110-7. [PMID: 4552797 DOI: 10.1016/0003-9861(72)90304-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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53 |
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Richards WO, Webb WA, Morris SJ, Davis RC, McDaniel L, Jones L, Littauer S. Patient management after endoscopic removal of the cancerous colon adenoma. Ann Surg 1987; 205:665-72. [PMID: 3592809 PMCID: PMC1493090 DOI: 10.1097/00000658-198706000-00008] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The subject of management of patients after endoscopic removal of cancerous adenomas is controversial. A retrospective review of 126 lesions in 121 patients who had had colonoscopic polypectomy of malignant lesions between 1971 and 1985 was used to determine the criteria for colon resection. Invasive cancer was identified in 80 patients, while 41 patients had carcinoma in situ. A synchronous colon cancer was found in five of the 121 patients. The patients who had carcinoma in situ had no evidence of residual tumor or metastatic disease on subsequent follow-up (colon resection in three patients and endoscopic surveillance in 38 patients). Of the 80 patients with invasive cancer, 44 had subsequent colon resection, and 34 of these had no evidence of tumor in the resected bowel or mesenteric lymph nodes. Ten patients had residual tumor, metastatic cancer to regional lymph nodes, or both. Each of the 10 had at least one of the following indications of inadequate resection or dissemination of disease to local lymph nodes (the first indication is a macroscopic evaluation, while the remaining four are all microscopic): incomplete excision, poorly differentiated tumor, invasion of the line of resection, invasion of the polyp stalk, and invasion of venous or lymphatic channels. Present recommendations for patient management after endoscopic removal of an invasive malignant adenoma should include colon resection with regional lymphadenectomy for patients with one or more of these five criteria. Patients without any of these risk factors should have early repeat endoscopic examination 3 months after initial polypectomy to evaluate the polypectomy site. Total colonoscopic examination is repeated at 1 year to ensure the surveillance program is begun with a colon without neoplasms.
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research-article |
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50 |
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Hobbs FDR, Davis RC, Roalfe AK, Hare R, Davies MK. Reliability of N-terminal proBNP assay in diagnosis of left ventricular systolic dysfunction within representative and high risk populations. Heart 2004; 90:866-70. [PMID: 15253955 PMCID: PMC1768355 DOI: 10.1136/hrt.2003.014258] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To determine the performance of a new NT-proBNP assay in comparison with brain natriuretic peptide (BNP) in identifying left ventricular systolic dysfunction (LVSD) in randomly selected community populations. METHODS Blood samples were taken prospectively in the community from 591 randomly sampled individuals over the age of 45 years, stratified for age and socioeconomic status and divided into four cohorts (general population; clinically diagnosed heart failure; patients on diuretics; and patients deemed at high risk of heart failure). Definite heart failure (left ventricular ejection fraction (LVEF) < 40%) was identified in 33 people. Samples were handled as though in routine clinical practice. The laboratories undertaking the assays were blinded. RESULTS Using NT-proBNP to diagnose LVEF < 40% in the general population, a level of > 40 pmol/l had 80% sensitivity, 73% specificity, 5% positive predictive value (PPV), 100% negative predictive value (NPV), and an area under the receiver-operator characteristic curve (AUC) of 76% (95% confidence interval (CI) 46% to 100%). For BNP to diagnose LVSD, a cut off level of > 33 pmol/l had 80% sensitivity, 88% specificity, 10% PPV, 100% NPV, and AUC of 88% (95% CI 75% to 100%). Similar NPVs were found for patients randomly screened from the three other populations. CONCLUSIONS Both NT-proBNP and BNP have value in diagnosing LVSD in a community setting, with similar sensitivities and specificities. Using a high cut off for positivity will confirm the diagnosis of LVSD but will miss cases. At lower cut off values, positive results will require cardiac imaging to confirm LVSD.
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Validation Study |
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49 |
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Holm C, Davis RC, Osterlund T, Schotz MC, Fredrikson G. Identification of the active site serine of hormone-sensitive lipase by site-directed mutagenesis. FEBS Lett 1994; 344:234-8. [PMID: 8187891 DOI: 10.1016/0014-5793(94)00403-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The consensus pentapeptide GXSXG is found in virtually all lipases/esterases and generally contains the active site serine. The primary sequence of hormone-sensitive lipase contains a single copy of this pentapeptide, surrounding Ser-423. We have analyzed the catalytic role of Ser-423 by site-directed mutagenesis and expression of the mutant hormone-sensitive lipase in COS cells. Substitution of Ser-423 by several different amino acids resulted in the complete abolition of both lipase and esterase activity, whereas mutation of other conserved serine residues had no effect on the catalytic activity. These results strongly suggest that Ser-423 is the active site serine of hormone-sensitive lipase.
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31 |
48 |
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Holmes PV, Davis RC, Masini CV, Primeaux SD. Effects of olfactory bulbectomy on neuropeptide gene expression in the rat olfactory/limbic system. Neuroscience 1998; 86:587-96. [PMID: 9881871 DOI: 10.1016/s0306-4522(98)00029-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bilateral olfactory bulbectomy in the rat produces a well-characterized syndrome that is independent of anosmia. This syndrome is reversed by chronic antidepressant administration, which provides the basis for the olfactory bulbectomy model of depression. The present experiments focused on neuropeptide plasticity in central olfactory/limbic structures following olfactory bulbectomy in rats. Male Sprague-Dawley rats received bilateral surgical ablation of the olfactory bulbs, sham surgery, or no surgery and were killed either three, seven, 14 or 28 days later. Relative levels of messenger RNA encoding neuropeptide Y, somatostatin, thyrotropin-releasing hormone, and corticotropin-releasing factor precursors in the forebrain were measured by quantitative in situ hybridization histochemistry using oligonucleotide probes. Prepro-neuropeptide Y messenger RNA levels in the piriform cortex and dentate gyrus were significantly elevated in bulbectomized rats 14 and 28 days after surgery compared to sham-operated and surgically naive rats. Prepro-somatostatin messenger RNA levels in the piriform cortex were marginally increased in bulbectomized rats at these time-points. Thyrotropin-releasing hormone and corticotropin-releasing factor precursor messenger RNA levels were not altered in the brain regions studied. The results indicate that olfactory bulbectomy causes long-term increases in the expression of the neuropeptide Y gene. These findings suggest that neuropeptide Y plasticity in the olfactory/limbic system may contribute to the olfactory bulbectomy syndrome in rats, and they provide further evidence of a role for neuropeptide Y in the pathophysiology of depression.
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Davis RC, Stahnke G, Wong H, Doolittle MH, Ameis D, Will H, Schotz MC. Hepatic lipase: site-directed mutagenesis of a serine residue important for catalytic activity. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39324-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Davis RC, Hobbs FDR, Kenkre JE, Roalfe AK, Hare R, Lancashire RJ, Davies MK. Prevalence of left ventricular systolic dysfunction and heart failure in high risk patients: community based epidemiological study. BMJ 2002; 325:1156. [PMID: 12433768 PMCID: PMC133457 DOI: 10.1136/bmj.325.7373.1156] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To determine the prevalence of left ventricular systolic dysfunction, and of heart failure due to different causes, in patients with risk factors for these conditions. DESIGN Epidemiological study, including detailed clinical assessment, electrocardiography, and echocardiography. SETTING 16 English general practices, representative for socioeconomic status and practice type. PARTICIPANTS 1062 patients (66% response rate) with previous myocardial infarction, angina, hypertension, or diabetes. MAIN OUTCOME MEASURES Prevalence of systolic dysfunction, both with and without symptoms, and of heart failure, in groups of patients with each of the risk factors. RESULTS Definite systolic dysfunction (ejection fraction <40%) was found in 54/244 (22.1%, 95% confidence interval 17.1% to 27.9%) patients with previous myocardial infarction, 26/321 (8.1%, 5.4% to 11.6%) with angina, 7/388 (1.8%, 0.7% to 3.7%) with hypertension, and 12/208 (5.8%, 3.0% to 9.9%) with diabetes. In each group, approximately half of these patients had symptoms of dyspnoea, and therefore had heart failure. Overall rates of heart failure, defined as symptoms of dyspnoea plus objective evidence of cardiac dysfunction (systolic dysfunction, atrial fibrillation, or clinically significant valve disease) were 16.0% (11.6% to 21.2%) in patients with previous myocardial infarction, 8.4% (5.6% to 12.0%) in those with angina, 2.8% (1.4% to 5.0%) in those with hypertension, and 7.7% (4.5% to 12.2%) in those with diabetes. CONCLUSION Many people with ischaemic heart disease or diabetes have systolic dysfunction or heart failure. The data support the need for trials of targeted echocardiographic screening, in view of the major benefits of modern treatment. In contrast, patients with uncomplicated hypertension have similar rates to the general population.
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Multicenter Study |
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Menzoian JO, Davis RC, Idelson BA, Mannick JA, Berger RL. Coronary artery by-pass surgery and renal transplantation: a case report. Ann Surg 1974; 179:63-4. [PMID: 4594220 PMCID: PMC1355716 DOI: 10.1097/00000658-197401000-00012] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Case Reports |
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