bluuebunny/crossref_metadata_2025_split huggingface dataset:
Standardizing a Composite Measure of Linkage Disequilibrium
Authors: Hamilton D. C. , Cole D. E. C. 
Published: June 2004

SummaryThe maximum and minimum are obtained for a composite measure of linkage disequilibrium used with genotypic data when the phase of double heterozygotes cannot be determined. These bounds are used to standardize the composite measure in the same way used for D′, the standardized gametic measure of linkage disequilibrium. Standardization produces a measure which lies between −1 and 1, and allows comparison of linkage disequilibrium between populations. The method is illustrated using two loci in the CASR gene.
Heritability of C‐Reactive Protein and Association with Apolipoprotein E Genotypes in Japanese Americans
Authors: Austin M. A. , Zhang C. , Humphries S. E. , Chandler W. L. , Talmud P. J. , Edwards K. L. , Leonetti D. L. , Mcneely M. J. , Fujimoto W. Y. 
Published: June 2004

SummaryNumerous studies have demonstrated that increased C‐reactive protein (CRP) levels predict coronary heart disease, stroke, peripheral vascular disease, and diabetes, and are associated with features of the metabolic syndrome. Only three previous studies have investigated the heritability of CRP levels, primarily in samples of Caucasian families.The purpose of the present study was to estimate the magnitude of genetic influences on CRP levels, and to examine potential associations between variation in the APOE gene and CRP levels, using a sample of 562 individual Japanese Americans from 68 extended kindreds. In general, correlation coefficients between first‐degree relatives for CRP were approximately 0.2, and spouse correlations did not differ from zero, consistent with genetic influences. Heritability estimates were approximately 0.3 (p < 0.01), even with adjustment for factors known to influence CRP levels. A significant relationship was seen between unadjusted CRP levels and APOE genotypes (p = 0.02), with the highest mean CRP level among ɛ2 carriers (1.20 mg/L), and nearly the same mean levels among ɛ3/ɛ3 subjects and ɛ4 carriers (0.72 and 0.74 mg/L, respectively). However, this relationship was diminished with adjustment for covariates (p = 0.07). These results demonstrate the presence of both genetic and environmental effects on CRP levels among Asian Americans, and additional studies are needed to determine if the APOE gene contributes to these genetic influences.
Age Related Changes in 5‐methylcytosine Content in Human Peripheral Leukocytes and Placentas: an HPLC‐based Study
Authors: Fuke C. , Shimabukuro M. , Petronis A. , Sugimoto J. , Oda T. , Miura K. , Miyazaki T. , Ogura C. , Okazaki Y. , Jinno Y. 
Published: June 2004

SummaryThe goal of the present study was to investigate inter‐individual and age‐dependent variation of global DNA methylation in human tissues. In this work, we examined 5‐methyldeoxycytidine (metC) content by HPLC in human peripheral blood leukocytes obtained from 76 healthy individuals of ages varying from 4 to 94 years (yr), and 39 human placentas from various gestational stages. The HPLC analysis revealed a significant variation of metC across individuals and is consistent with the previous findings of age‐dependent decrease of global methylation levels in human tissues. The age‐dependent decrease of metC was relatively small, but statistically highly significant (p= 0.0002) in the aged group (65.9 ± 8.9 [mean age ± SD] yr; n = 22) in comparison to the young adult group (19.3 ± 1.4 yr; n = 21). Males showed a subtle but statistically significant higher mean metC content than females. In contrast to the peripheral blood samples, DNA extracted from placentas exhibited gestational stage‐dependent increase of methylation levels that appeared to inversely correlate with the expression levels of human endogenous retroviruses. These data may be helpful in further studies of DNA methylation, such as inheritance of epigenetic patterns, environment‐induced changes, and involvement of epigenetic changes in disease.
The Sib TDT Adjusted For Age Of Disease Onset
Authors: Ghosh Saurabh , Reich Theodore 
Published: June 2004

SummarySince the Sib‐TDT (Spielman & Ewens, 1998) ignores age of disease onset, there could be loss of power in detecting linkage. In this article, we propose an adjustment for age of onset using the Cox Proportional Hazard Model (Cox, 1972) with the marker allele as a covariate. The test statistic for linkage is identical to the traditional Sib‐TDT. Monte‐Carlo simulations are performed under different disease models to assess the increase in power of the age‐adjusted Sib‐TDT compared to the traditional Sib‐TDT. We extend our method to multiallelic markers. An application using data on Alzheimer's Disease is also presented.
Clinical Experience with a New Detection Algorithm for Differentiation of Supraventricular from Ventricular Tachycardia in a Dual‐Chamber Defibrillator
Authors: SINHA ANIL‐MARTIN , STELLBRINK CHRISTOPH , SCHUCHERT ANDREAS , MÖX BERNHARD , JORDAENS LUC , LAMAISON DOMINIQUE , GILL JASWINDER , KAPLAN ANDREW , MERKELY BELA ,   Phylax AV Investigator Group
Published: May 2004

Introduction: Inadequate therapy for supraventricular tachyarrhythmias (SVT) is a frequent problem of implantable cardioverter defibrillators (ICD). Dual‐chamber ICDs have been developed to improve discrimination of SVT from ventricular tachycardia (VT). We investigated the positive predictivity, sensitivity, and specificity of a new algorithm, the SMART detection™ algorithm, incorporated in the Phylax AV (Biotronik) dual‐chamber ICD. Methods and Results: Two hundred nine patients (185 men, age 64 ± 11 years) received a Phylax AV ICD with SMART detection™ activated. In 138 of these patients, 1,245 sustained tachycardia episodes with a detailed electrogram were stored in the device during a follow‐up period of 10 ± 6 months. Episodes were correctly classified as ventricular fibrillation (VF, n = 178) in 52 patients, VT (n = 641) in 98 patients, and SVT (n = 385) in 48 patients by the algorithm. Forty‐one true SVT episodes (3.3%) were misclassified as VT: atrial fibrillation (n = 7) and flutter (n = 1), sinus tachycardia (n = 12), and other SVT (n = 21). The positive predictivity for VF/VT was 94.5% (95% CI 92.7–95.8) uncorrected and 94.5% (95% CI 92.9–95.8%) corrected with the generalized equation estimation (GEE) method. The positive predictivity for SVT was 100%. The specificity was 88.9% (95% CI 85.6–91.6%) uncorrected and 89.0% (95% CI 85.6–91.6%) corrected with the GEE method with a sensitivity of 100%. Conclusion: The SMART detection™ algorithm was safe and reliable for the detection of all ventricular tachycardias. Although its specificity was high, it should be improved with regard to SVT to avoid inappropriate ICD therapies. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1‐7, June 2004)
Predictors of Recurrence Following Catheter Ablation of Atrial Fibrillation Using an Irrigated‐Tip Ablation Catheter
Authors: VASAMREDDY CHANDRASEKHAR R. , LICKFETT LARS , JAYAM VINOD K. , NASIR KHURRAM , BRADLEY DAVID J. , ELDADAH ZAYD , DICKFELD TIMM , BERGER RONALD , CALKINS HUGH 
Published: May 2004

Introduction: The aims of this study were to identify predictors of recurrence after catheter ablation of atrial fibrillation (AF) and to report the safety and efficacy of catheter ablation of AF using an irrigated‐tip ablation catheter. Methods and Results: Seventy‐five consecutive patients (51 men [68%]; age 54 ± 13 years) with symptomatic drug‐refractory paroxysmal (42 patients), persistent (21 patients), or permanent (12 patients) AF underwent catheter ablation of AF using an irrigated‐tip ablation catheter and a standard ablation strategy, which involved electrical isolation of all pulmonary veins (PVs) and creation of a cavotricuspid linear lesion. At 10.5 ± 7.5 months of follow‐up following a single (n = 75) or redo ablation procedure (n = 11), 39 (52%) of the 75 patients were free of AF, 10 were improved (13%), and 26 had experienced no benefit from the ablation procedure (35%). Seventy‐six percent of patients with paroxysmal AF were free from recurrent AF. The most significant complications were two episodes of pericardial tamponade, mitral valve injury in one patient, two strokes, and complete but asymptomatic PV stenosis in one patient. Cox proportional hazards multivariate regression analysis identified the presence of persistent AF, permanent AF, and age >50 years prior to the ablation are the only independent predictors of AF recurrence after the first PV isolation procedure. Conclusion: Catheter ablation of AF using a strategy involving isolation of all PVs and creation of a linear lesion in the cavotricuspid isthmus using cooled radiofrequency energy is associated with moderate efficacy and an important risk for complications. The best results of this procedure are achieved in the subset of patients who are younger than 50 years and have only paroxysmal AF. (J Cardiovasc Electrophysiol, Vol. 15, pp. 692‐697, June 2004)
Clinical Characteristics of Subjects with the Brugada‐Type Electrocardiogram:
Authors: MATSUO KIYOTAKA , AKAHOSHI MASAZUMI , NAKASHIMA EIJI , SETO SHINJI , YANO KATSUSUKE 
Published: May 2004

Introduction: The Brugada‐type ECG, a terminal r′ wave accompanied by ST segment elevation in the right precordial leads, is not a very rare condition. Most of the cases are men in Japan and elsewhere; however, information about the clinical features of these cases is lacking. The aim of this study was to determine the clinical characteristics of subjects with the Brugada‐type ECG, specifically Japanese men. Methods and Results: We extracted male Brugada‐type ECG cases from 3,374 men followed biennially from 1958 through 2001 in Nagasaki, Japan, and compared the clinical characteristics at diagnosis between these cases and four age‐matched male controls for each case. A total of 34 cases with the Brugada‐type ECG were observed during follow‐up. Body mass index (BMI) at diagnosis was significantly lower in Brugada‐type ECG cases than in 136 controls (20.2 ± 2.1 kg/m2 vs 21.8 ± 2.8 kg/m2, P = 0.003). The BMI trend in cases was always lower than that in controls throughout the 8‐year observation period (from 4 years before diagnosis to 4 years after diagnosis). Pulse rate at diagnosis was also somewhat lower in Brugada‐type ECG cases than in controls (68.9 ± 7.7 beats/min vs 72.7 ± 11.1 beats/min, P = 0.038). The significance disappeared after controlling for BMI (P = 0.131) or body weight (P = 0.153). Conclusion: The cases with the Brugada‐type ECG had lower BMI than controls, leading to a clue to possible basic mechanisms of the Brugada‐type ECG with a focus on this association. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1‐5, June 2004)
Single‐Stage Adenosine Tilt Testing in Patients with Unexplained Syncope
Authors: MITTAL SUNEET , STEIN KENNETH M. , MARKOWITZ STEVEN M. , IWAI SEI , GUTTIGOLI AMIT , LERMAN BRUCE B. 
Published: May 2004

Introduction: We previously have shown that a 3‐minute single‐stage adenosine tilt test has a diagnostic yield comparable to a two‐stage protocol consisting of a 30‐minute drug‐free tilt followed by a 15‐minute isoproterenol tilt. In this study, we sought to further define the clinical utility of adenosine tilt testing in patients with unexplained syncope by prospectively evaluating test specificity and determining predictors of a positive test response. Methods and Results: The specificity of single‐stage adenosine tilt testing was determined using 30 control subjects. To determine the diagnostic yield of this protocol, adenosine tilts were performed in 129 patients with unexplained syncope. The adenosine tilt test protocol had high specificity (100%) but a low overall diagnostic yield (18%). However, the yield was affected significantly by age. In patients ≤40 years of age, the tilt test was positive in 15 (41%) of 37 patients, which was significantly greater than the yield in patients between the ages of 41 and 64 years (6/41 patients [15%], P = 0.012) and those ≥65 years of age (2/41 patients [5%], P < 0.0001). Conclusion: These data support single‐stage adenosine tilt testing in patients ≤40 years of age because the diagnostic yield of the test is maximal in this group and the test can be completed in ≤3 minutes. Conversely, the diagnostic yield of adenosine tilt testing in patients >40 years of age is low, suggesting that the clinical utility of this protocol is limited in these patients. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1‐4, June 2004)
Entrainment Mapping of Dual‐Loop Macroreentry in Common Atrial Flutter:
Authors: FUJIKI AKIRA , NISHIDA KUNIHIRO , SAKABE MASAO , SUGAO MASATAKA , TSUNEDA TAKAYUKI , MIZUMAKI KOICHI , INOUE HIROSHI 
Published: May 2004

Introduction: The aim of this study was to determine using entrainment mapping whether the reentrant circuit of common type atrial flutter (AFL) is single loop or dual loop. Methods and Results: In 12 consecutive patients with counterclockwise (CCW) AFL, entrainment mapping was performed with evaluation of atrial electrograms from the tricuspid annulus (TA) and the posterior right atrial (RA) area. We hypothesized that a dual‐loop reentry could be surmised from “paradoxical delayed capture” of the proximal part of the circuit having a longer interval from the stimulus to the captured beat compared with the distal part of the circuit. In 6 of 12 patients with CCW AFL, during entrainment from the septal side of the posterior blocking line, the interval from the stimulus to the last captured beat was longer at the RA free wall than at the isthmus position. In these six patients with paradoxical delayed capture, flutter cycle length (FCL) was 227 ± 12 ms and postpacing interval minus FCL was significantly shorter at the posterior blocking line than at the RA free wall (20 ± 11 ms vs 48 ± 33 ms, P < 0.05). In two of these patients, early breakthrough occurred at the lateral TA. A posterior block line was confirmed in all six patients in the sinus venosa area by intracardiac echocardiography. Conclusion: Half of the patients with common type AFL had a dual‐loop macroreentrant circuit consisting of an anterior loop (circuit around the TA) and a posterior loop (circuit around the inferior vena cava and the posterior blocking line). (J Cardiovasc Electrophysiol, Vol. 15, pp. 679‐685, June 2004)
Vagal Activity Modulates Spontaneous Augmentation of ST Elevation in the Daily Life of Patients with Brugada Syndrome
Authors: MIZUMAKI KOICHI , FUJIKI AKIRA , TSUNEDA TAKAYUKI , SAKABE MASAO , NISHIDA KUNIHIRO , SUGAO MASATAKA , INOUE HIROSHI 
Published: May 2004

Introduction: In Brugada syndrome, ventricular fibrillation (VF) occurs mainly during sleep, and Brugada ECG signs are intensified by parasympathomimetic drugs; therefore, vagal activity could be a precipitating factor of VF. The aim of the present study was to elucidate the relation between spontaneous augmentation of ST elevation and changes in autonomic nervous activities in the daily life of patients with Brugada syndrome. Methods and Results: Twenty‐three consecutive patients with Brugada syndrome were studied. Group VF(+) consisted of 7 symptomatic patients and 3 asymptomatic patients with inducible VF; group VF(–) consisted of 13 asymptomatic patients without documented or inducible VF. Two‐channel unipolar lead (V1 and V2) Holter ECG was recorded. Heart rate variability was analyzed by the maximum entropy method. Spontaneous augmentation of ST elevation (≥1.5 mm/20min) occurred more frequently during 24 hours in group VF(+) than in group VF(–) (5.7 ± 2.5 times vs 2.3 ± 2.4 times, P < 0.01). ST elevation was significantly greater in group VF(+) than in group VF(–) (2.1 ± 0.2 mm vs 1.8 ± 0.2 mm, P < 0.05). Power of the high‐frequency component (HF: 0.15–0.4 Hz) and RR interval increased progressively, and the ratio of low‐frequency component (LF; 0.04– 0.15 Hz) to high‐frequency component (LF/HF) gradually decreased toward the time of maximum ST elevation. During an entire day, daytime (0–5 P.M.), and nighttime (0–5 A.M.), both HF and LF/HF were not different between groups VF(+) and VF(–). Conclusion: In Brugada syndrome, spontaneous augmentation of ST elevation in daily life occurred along with an increase in vagal activity. ST elevation was augmented more in patients with VF than in those without VF under similar vagal tone. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1‐7, June 2004)
Supercooling and cold‐hardiness in eggs of western and northern corn rootworms
Authors: Ellsbury M. M. , Lee R. E. 
Published: May 2004

AbstractOviposition by northern corn rootworms, Diabrotica barberi Smith and Lawrence, and western corn rootworms, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), key pests of corn in the Great Plains of the USA, occurs in the soil during late summer. Overwintering eggs are exposed to variable soil moisture and temperatures below −5 °C. The winter mortality of eggs in the soil is a primary factor that determines the potential for larval injury to corn the following spring. Our studies aimed to determine the comparative supercooling capacities of northern and western corn rootworm eggs and to assess egg mortality following brief exposure to extreme low temperature, ranging from −12.0 to −21.5 °C, under three moisture regimes. Eggs of northern corn rootworm were supercooled to a temperature as low as −27 °C, and survived supercooling to a greater extent than did western corn rootworm eggs. Moisture treatment prior to supercooling had little effect on northern corn rootworm eggs. Western corn rootworm eggs were more resistant than northern corn rootworm eggs to the effects of desiccation followed by supercooling. The survival of northern corn rootworm eggs was better than western corn rootworms under dry conditions, followed by exposure to temperatures of −12.0 and −17.5 °C, but was very low at −21.5 °C, regardless of the moisture regime. The results suggest that moisture and temperature may interact in the soil environment to determine the overwintering survival of corn rootworms. It is evident from these studies that both rootworm species experience mortality at temperatures well above the supercooling points of the eggs, but that differences exist in the effects of substrate moisture treatments on the cold‐hardiness of eggs from the two species.
Comparing floral nectar and aphid honeydew diets on the longevity and nutrient levels of a parasitoid wasp
Authors: Lee Jana C. , Heimpel George E. , Leibee Gary L. 
Published: May 2004

AbstractWe compared the effects of floral nectar from buckwheat, Fagopyrum esculentum Moench, and honeydew produced by the soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae), on longevity, nutrient levels, and egg loads of the parasitoid Diadegma insulare Cresson (Hymenoptera: Ichneumonidae). Diadegma insulare lived for 2 days in control treatments of water or clean soybean leaves, for 6–7 days with honeydew, and in excess of 2 weeks with buckwheat nectar. Potential reasons for the superiority of buckwheat nectar over soybean aphid honeydew for extending the longevity of parasitoids include: (i) parasitoids ingest more sugars from floral sources, (ii) oligosaccharides in honeydew have a lower nutritional value than nectar sugars, and (iii) honeydew has antagonistic compounds. Overall sugar levels were lower in honeydew‐ vs. nectar‐fed female wasps, suggesting a lower feeding rate, but other explanations cannot be excluded. Diadegma insulare eclosed with high levels of lipids and glycogen, and low levels of gut and storage sugars. All carbohydrates increased over the life of both nectar‐ and honeydew‐fed wasps, but remained low or decreased in starved wasps. Lipid levels declined over the lifespan of female wasps, but females fed floral nectar showed the slowest rate of lipid decline. Diet did not affect egg load, probably because the females were not given hosts in the experiment.
Feeding responses of specialist herbivores to plant extracts and pure allelochemicals: effects of prolonged exposure
Authors: Akhtar Yasmin , Isman Murray B. 
Published: May 2004

AbstractWe investigated the possibility of decreased feeding deterrent response following prolonged exposure in three specialist herbivores, Plutella xylostella (larvae), Pseudaletia unipuncta (larvae), and Epilachna varivestis (adults) through leaf disc choice and no‐choice tests. Neonate larvae (<24 h old) of the three species were reared on their host plants sprayed with the antifeedants until tested. Our results demonstrated that Ps. unipuncta did not show a decrease in feeding deterrent response to extracts of Melia volkensii (choice and no‐choice tests) or oregano (Origanum vulgare) (choice test) following prolonged exposure. Plutella xylostella exhibited a decrease in feeding deterrent response to M. volkensii in a choice test only, but not to oregano. Although not significant, we did find a trend toward decreasing feeding deterrent response to M. volkensii by both species in no‐choice tests. However, both species exhibited a significant decrease in feeding deterrent response to pure allelochemicals (Ps. unipuncta to thymol, and P. xylostella to thymol and toosendanin) compared with the naïve groups, following prolonged exposure in leaf disc choice tests. Epilachna varivestis showed a significant decrease in feeding deterrent responses to both oregano and thymol in leaf disc choice tests. We conclude from our present and previous studies that not only are there interspecific differences between generalist and specialist species but also among specialist species.
Influence of plant sulphur nutrition on oviposition and larval performance of the diamondback moth
Authors: Marazzi Cristina , Städler Erich 
Published: May 2004

AbstractWe measured adult oviposition preference, larval growth, and feeding behaviour of the crucifer specialist Plutella xylostella (L.) (Lepidoptera: Plutellidae) on plants of Brassica napus (L.) cv. Express (Brassicaceae), grown under three different sulphur regimes. The nutrient solutions used were the following: one sulphur‐free (S0), one normal sulphur (Sn, normal field concentration), and one sulphur‐rich (S+, double concentration of Sn). Females laid more eggs on Sn than on S0 plants, while only a slight, non‐significant difference was observed between Sn and S+ plants. Moreover, the development time from hatching to emergence was significantly shorter, and adults were heavier on Sn than on S0 plants. Comparing these same two parameters from Sn and S+ plants, we found a shorter development time on plants rich in sulphur, although this trend was not statistically significant. Larval feeding preferences were tested in a dual choice assay using leaf discs. A significantly higher number of larvae preferred leaf discs of Sn plants than those of S0 plants. Furthermore, the larvae preferred S+ to Sn discs. An optimal supply of sulphur to oilseed rape is necessary for a good seed harvest, and it also plays an important role in acceptance by P. xylostella of the host plant. Maintaining higher levels of sulphur in the plant nutrient solution benefits insect performance, both at the adult and larval stage.