In vitro fibrin clot formation and fibrinolysis using heterozygous plasma fibrinogen from gamma Asn319, Asp320 deletion dysfibrinogen, Otsu I

ArticleTHROMBOSIS RESEARCH. 118(5): 651-661 (2006)journal articl

Failure of Conventional Density Functionals for the Prediction of Molecular Crystal Polymorphism: A Quantum Monte Carlo Study

We have applied the diffusion Monte Carlo method, for the first time, to an organic molecular crystal (para-diiodobenzene) in order to determine the relative stability of its two well-known polymorphs. The DMC result predicts that the α phase is more stable than the β phase at zero temperature, in agreement with experiment. In comparison, we evaluated four commonly used local, semilocal, and hybrid density functionals, including an empirical correction to include the effects of dispersion. We conclude that while density functional theory may provide the most practical method for estimating the effects of electron correlation, conventional functionals which do not accurately describe noncovalent interactions may not be considered reliable for determining highly accurate energies in such systems.Chemistry and Chemical Biolog

Translation and validation of a Japanese version of the irritable bowel syndrome-quality of life measure (IBS-QOL-J)

AIMS: To compare quality of life (QOL) for patients with irritable bowel syndrome (IBS) between the U.S. and Japan, it is indispensable to develop common instruments. The IBS-QOL, which is widely used in Western countries, was translated into Japanese as there has been a lack of Japanese disease-specific QOL measures for IBS. METHODS: The original 34 items of the IBS-QOL were translated from English into Japanese through two independent forward translations, resolution, back translation, and resolution of differences. Forty nine patients who had GI symptoms but did not have any organic diseases (including 30 IBS patients diagnosed by Rome II criteria) were recruited from Tohoku University Hospital in Sendai, Japan and completed a Japanese version of the IBS-QOL (IBS-QOL-J) concomitant with a Japanese version of the IBS severity index (IBSSI-J) twice within 7–14 days. RESULTS: The IBS-QOL-J demonstrated high internal consistency (Cronbach's alpha; 0.96) and high reproducibility (intraclass correlation coefficient; 0.92, p < 0.001). Convergent analyses confirmed that the overall score of IBS-QOL-J was significantly correlated with overall severity of IBS symptoms on the IBSSI-J (r = -0.36, p = 0.01) and with the individual items on the IBSSI-J that assess interference with life in general (r = -0.47, p = 0.001) and dissatisfaction with bowel habits (r = -0.32, p < 0.05). Eight patients who reported continuous abdominal pain in the past 6 months had significantly lower scores in the IBS-QOL-J than those who did not (53.7 +- 12.7 vs. 73.6 +- 19.5, p < 0.01). Age, sex, education or marital status did not affect scores on the measure. CONCLUSION: The IBS-QOL-J is a reliable instrument to assess the disease-specific QOL for IBS. Considering cross-cultural comparison, this measure is likely to be a valuable tool to investigate the QOL in Japanese patients with IBS

Noncovalent Interactions by QMC: Speedup by One-Particle Basis-Set Size Reduction

While it is empirically accepted that the fixed-node diffusion Monte-Carlo (FN-DMC) depends only weakly on the size of the one-particle basis sets used to expand its guiding functions, limits of this observation are not settled yet. Our recent work indicates that under the FN error cancellation conditions, augmented triple zeta basis sets are sufficient to achieve a benchmark level of 0.1 kcal/mol in a number of small noncovalent complexes. Here we report on a possibility of truncation of the one-particle basis sets used in FN-DMC guiding functions that has no visible effect on the accuracy of the production FN-DMC energy differences. The proposed scheme leads to no significant increase in the local energy variance, indicating that the total CPU cost of large-scale benchmark noncovalent interaction energy FN-DMC calculations may be reduced.Comment: ACS book chapter, accepte

Contributions of the direct supply of belowground seagrass detritus and trapping of suspended organic matter to the sedimentary organic carbon stock in seagrass meadows

Carbon captured by marine living organisms is called blue carbon, and seagrass meadows are a dominant blue carbon sink. However, our knowledge of how seagrass increases sedimentary organic carbon (OC) stocks is limited. We investigated two pathways of OC accumulation: trapping of organic matter in the water column and the direct supply of belowground seagrass detritus. We developed a new type of box corer to facilitate the retrieval of intact cores that preserve the structures of both sediments (including coarse sediments and dead plant structures) and live seagrasses. We measured seagrass density, total OC mass (OCtotal) (live seagrass OC biomass (OCbio) + sedimentary OC mass (OCsed)), and the stable carbon isotope ratio (δ13C) of OCsed and its potential OC sources at Thalassia hemprichii dominated back-reef and Enhalus acoroides dominated estuarine sites in the tropical Indo-Pacific region. At points with vegetation, OCbio accounted for 25 % and OCsed for 75 % of OCtotal; this contribution of OCbio to OCtotal is higher than in globally compiled data. Belowground detritus accounted for  ∼  90 % of the OC mass of dead plant structures (&gt; 2 mm in size) (OCdead). At the back-reef site, belowground seagrass biomass, OCdead, and δ13C of OCsed (δ13Csed) were positively correlated with OCsed, indicating that the direct supply of belowground seagrass detritus is a major mechanism of OCsed accumulation. At the estuarine site, aboveground seagrass biomass was positively correlated with OCsed but δ13Csed did not correlate with OCsed, indicating that trapping of suspended OC by seagrass leaves is a major mechanism of OCsed accumulation there. We inferred that the relative importance of these two pathways may depend on the supply (productivity) of belowground biomass. Our results indicate that belowground biomass productivity of seagrass meadows, in addition to their aboveground morphological complexity, is an important factor controlling their OC stock. Consideration of this factor will improve global blue carbon estimates.</p

Endo-Epicardial Homogenization of the Scar Versus Limited Substrate Ablation for the Treatment of Electrical Storms in Patients With Ischemic Cardiomyopathy

ObjectivesThis study investigated the impact on recurrences of 2 different substrate approaches for the treatment of these arrhythmias.BackgroundCatheter ablation of electrical storms (ES) for ventricular arrhythmias (VAs) has shown moderate long-term efficacy in patients with ischemic cardiomyopathy.MethodsNinety-two consecutive patients (81% male, age 62 ± 13 years) with ischemic cardiomyopathy and ES underwent catheter ablation. Patients were treated either by confining the radiofrequency lesions to the endocardial surface with limited substrate ablation (Group 1, n = 49) or underwent endocardial and epicardial ablation of abnormal potentials within the scar (homogenization of the scar, Group 2, n = 43). Epicardial access was obtained in all Group 2 patients, whereas epicardial ablation was performed in 33% (14) of these patients.ResultsMean ejection fraction was 27 ± 5. During a mean follow-up of 25 ± 10 months, the VAs recurrence rate of any ventricular tachycardia (VTs) was 47% (23 of 49 patients) in Group 1 and 19% (8 of 43 patients) in Group 2 (log-rank p = 0.006). One patient in Group 1 and 1 patient in Group 2 died at follow-up for noncardiac reasons.ConclusionsOur study demonstrates that ablation using endo-epicardial homogenization of the scar significantly increases freedom from VAs in ischemic cardiomyopathy patients

Puzzle based teaching versus traditional instruction in electrocardiogram interpretation for medical students – a pilot study

<p>Abstract</p> <p>Background</p> <p>Most medical professionals are expected to possess basic electrocardiogram (EKG) interpretation skills. But, published data suggests that residents' and physicians' EKG interpretation skills are suboptimal. Learning styles differ among medical students; individualization of teaching methods has been shown to be viable and may result in improved learning. Puzzles have been shown to facilitate learning in a relaxed environment. The objective of this study was to assess efficacy of teaching puzzle in EKG interpretation skills among medical students.</p> <p>Methods</p> <p>This is a reader blinded crossover trial. Third year medical students from College of Human Medicine, Michigan State University participated in this study. Two groups (n = 9) received two traditional EKG interpretation skills lectures followed by a standardized exam and two extra sessions with the teaching puzzle and a different exam. Two other groups (n = 6) received identical courses and exams with the puzzle session first followed by the traditional teaching. EKG interpretation scores on final test were used as main outcome measure.</p> <p>Results</p> <p>The average score after only traditional teaching was 4.07 ± 2.08 while after only the puzzle session was 4.04 ± 2.36 (p = 0.97). The average improvement after the traditional session was followed up with a puzzle session was 2.53 ± 1.94 while the average improvement after the puzzle session was followed with the traditional session was 2.08 ± 1.73 (p = 0.67). The final EKG exam score for this cohort (n = 15) was 84.1 compared to 86.6 (p = 0.22) for a comparable sample of medical students (n = 15) at a different campus.</p> <p>Conclusion</p> <p>Teaching EKG interpretation with puzzles is comparable to traditional teaching and may be particularly useful for certain subgroups of students. Puzzle session are more interactive and relaxing, and warrant further investigations on larger scale.</p

Increased blood product use among coronary artery bypass patients prescribed preoperative aspirin and clopidogrel

BACKGROUND: The administration of antiplatelet drugs before coronary artery bypass graft surgery (CABG) is associated with an increased risk of major hemorrhage and related surgical reexploration. Little is known about the relative effect of combined clopidogrel and aspirin on blood product use around the time of CABG. We evaluated the associated risk between the combined use of aspirin and clopidogrel and the transfusion of blood products perioperatively. METHODS: We retrospectively studied a cohort of 659 individuals who underwent a first CABG, without concomitant valvular or aortic surgery, at a single large Canadian cardiac surgical centre between January 2000 and April 2002. The four study exposure groups were those prescribed aspirin (n = 105), clopidogrel (n = 11), the combination of both (n = 46), or neither drug (n = 497), within 7 days prior to CABG. The primary study outcome was the excessive transfusion of blood products during CABG and up to the second post-operative day, defined as ≥ 2 units of packed red blood cells (PRBC), ≥ 2 units of fresh frozen plasma, ≥ 5 units of cryoprecipitate or ≥ 5 units of platelets. Secondary outcomes included the mean number of transfused units of each type of blood product. RESULTS: A greater mean number of units of PRBC were transfused among those who received clopidogrel alone (2.9) or in combination with aspirin (2.4), compared to those on aspirin alone (1.9) or neither antiplatelet drug (1.4) (P = 0.001). A similar trend was seen for the respective mean number of transfused units of platelets (3.6, 3.7, 1.3 and 1.0; P < 0.001) and fresh frozen plasma (2.5, 3.1, 2.3, 1.6; P = 0.01). Compared to non-users, the associated risk of excessive blood product transfusion was highest among recipients of aspirin and clopidogrel together (adjusted OR 2.2, 95% CI 1.1–4.3). No significant association was seen among lone users of aspirin (adjusted OR 1.0, 95% CI 0.6–1.6) or clopidogrel (adjusted OR 0.7, 95% CI 0.2–2.5), compared to non-users. CONCLUSIONS: While combined use of aspirin and clopidogrel shortly before CABG surgery may increase the associated risk of excess transfusion of blood products perioperatively, several study limitations prevent any confident conclusions from being drawn. Beyond challenging these findings, future research might focus on the value of both intraoperative monitoring of platelet function, and the effectiveness of antifibrinolytic agents, at reducing the risk of postoperative bleeding