Distribution by Scientific Domains
Distribution within Earth and Environmental Science

Terms modified by Ma

  • ma cm
  • ma experiment
  • ma g
  • ma h g
  • ma nmr
  • ma nmr spectroscopy

  • Selected Abstracts

    Drug Self-Templated Synthesis of Ibuprofen/Mesoporous Silica for Sustained Release

    Fengyu Qu
    Abstract The synthesis of Ibuprofen/mesoporous silica has been achieved by a drug self-templated one-step co-condensation process. The drug template of Ibuprofen, a co-template of 3-aminopropyltriethoxysilane (APTES), and tetraethoxysiliane (TEOS) were self-assembled into Ibuprofen/mesoporous silica in a neutral aqueous reaction system. This drug/mesoporous silica was characterized by powder XRD diffraction, FTIR spectroscopy, N2 adsorption/desorption, TEM, and 29Si/MAS and 13C/MAS NMR spectroscopy. The Ibuprofen/mesoporous silica system gives a well-sustained release profile. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

    NMR spectroscopy of citrate in solids: cross-polarization kinetics in weakly coupled systems

    Jian Feng
    Abstract Solid-state NMR spectroscopy is a potentially powerful method for obtaining molecular level structural information crucial for understanding the specific relationship between calcite crystals and occluded organic molecules that are important in biomineralization and biomimetic materials. In this work, a method is developed based on cross-polarization/magic angle spinning (CP/MAS) NMR to measure the heteronuclear distances and obtain structural information for large intracrystalline citrate defects in a synthetic calcite/citrate composite. Using compounds with well-characterized crystal structures, Mg(II) citrate and Sr(II) citrate, a correlation is established between TIS, the CP time, and M2IS, the van Vleck heteronuclear dipolar second moment, which contains distance and structural information. This correlation is supported by peak assignments obtained from calculations of the 13C chemical shifts for crystalline Mg(II) citrate. On the basis of TIS,1versusM2IS correlation, measurement of TIS for carbonate ions associated with citrate defects in a calcite(13C-enriched)/citrate coprecipitate yields an estimate for the distance between citrate and the nearest carbonate carbon that indicates close spatial proximity and provides useful constraints for future computational study. The applicability of TIS,1versusM2IS correlations to other weakly coupled spin-1/2 systems is discussed in terms of the effects of 1H homonuclear dipolar coupling, using the CP kinetics of Zn(II) dihydroxybenzoate and kaolinite for comparison. The results suggest a limited range of correlation constants and indicate that quantitative information can be obtained from CP/MAS kinetics obtained under similar experimental conditions. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Solid-state NMR studies of the molecular structure of Taxol

    Yu Ho
    Abstract Solid-state 13C{1H} cross-polarization/magic angle spinning spectroscopy (CP/MAS) has been utilized to extract the molecular structure information of Taxol, which is an anti-tumor therapeutic medicine extracted from the yew bark. The 13C signals have chemical shift values quite consistent with those measured in solution phase, and the overall chemical shift range is over 200 ppm. Notably, most of the 13C resonances of the taxane ring have two clearly resolved spectral components except the resonance peaks of C-15, C-16 and C-17, which are located at the central part of the taxane ring. On the basis of our NMR data, we propose that these doublets originate from two slightly different molecular conformations of the taxane ring and still the central part of the ring remains structurally similar. Furthermore, it is demonstrated that the 13C chemical shift difference deduced from the doublet splittings can serve as a direct measure of the structural difference between the two conformations, which could possibly correlate with the anti-tumor activity of Taxol. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Solid-state 1H , 19F/19F , 1H CP/MAS NMR study of poly(vinylidene fluoride)

    Shinji Ando
    Abstract Solid-state 1H , 19F and 19F , 1H cross-polarization magic angle spinning (CP/MAS) NMR spectra have been investigated for a semicrystalline fluoropolymer, namely poly(vinylidene fluoride) (PVDF). The 1H , 19F CP/MAS spectra can be fitted by five Lorentzian functions, and the amorphous peaks were selectively observed by the DIVAM CP pulse sequences. Solid-state spin-lock experiments showed significant differences in T1,F and T1,H between the crystalline and amorphous domains, and the effective time constants, THF* and T1,*, which were estimated from the 1H , 19F CP curves, also clarify the difference in the strengths of dipolar interactions. Heteronuclear dipolar oscillation behaviour is observed in both standard CP and 1H , 19F inversion recovery CP (IRCP) experiments. The inverse 19F , 1H CP-MAS and 1H , 19F CP-drain MAS experiments gave complementary information to the standard 1H , 19F CP/MAS spectra in a manner reported in our previous papers for other fluoropolymers. The value of NF/NH (where N is a spin density) estimated from the CP-drain curve is within experimental error equal to unity, which is consistent with the chemical structure. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Preparation and Characterization of Inclusion Complexes of ,-Cyclodextrin with Ionic Liquid

    Yan-An Gao
    Abstract The solubilities of ,-cyclodextrin (,-CD), ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), and their mixture in water were determined, and the conductivity of these aqueous solutions was measured. It was demonstrated that ,-CD and bmimPF6 could enhance the solubility of each other, and the solubility curves of each were linear with gradients of about 1. The conductivity decreased remarkably with increasing , - CD concentration, and a discernible break in the conductivity curve could be observed when ,-CD and bmimPF6 were equimolar in the solution. The solubility and conductivity results indicated that inclusion complexes (ICs) of 1:1 stoichiometry were formed. The inclusion compounds were further characterized by using powder X-ray diffraction (XRD) analysis, 13C CP/MAS (cross-polarization magic-angle spinning) NMR and 1H NMR spectroscopy, and thermogravimetric analysis (TGA). The results showed that the ICs were a fine crystalline powder. The host,guest system exhibited a channel-type structure and each glucose unit of ,-CD was in a similar environment. The decomposition temperature of the ICs was lower than that of bmimPF6 and ,-CD individually. [source]

    Training response of mitochondrial transcription factors in human skeletal muscle

    ACTA PHYSIOLOGICA, Issue 1 2010
    J. Norrbom
    Abstract Aim:, Mitochondrial function is essential for physical performance and health. Aerobic fitness is positively associated with mitochondrial (mt) biogenesis in muscle cells through partly unknown regulatory mechanisms. The present study aimed to investigate the influence of exercise and training status on key mt transcription factors in relation to oxidative capacity in human skeletal muscle. Methods:, The basal mRNA and protein levels of mitochondrial transcription factor A (TFAM), mitochondrial transcription factors B1 (TFB1M) or B2 (TFB2M), and mRNA levels of mitochondrial transcription termination factor (mTERF), were measured in a cross-sectional study with elite athletes (EA) and moderately active (MA) and the basal mRNA levels of these factors were measured during a 10-day endurance training programme with (R-leg) and without (NR-leg) restricted blood flow to the working leg. Results:, TFAM protein expression was significantly higher in the EA than in the MA, while protein levels of TFB1M and TFB2M were not different between the groups. There was no difference between EA and MA, or any effect with training on TFAM mRNA levels. However, the mRNA levels of TFB1M, TFB2M and mTERF were higher in EA compared with MA. For TFB1M and TFB2M, the mRNA expression was increased in the R-leg after 10 days of training, but not in the NR-leg. mTERF mRNA levels were higher in EA compared with MA. Conclusion:, This study further establishes that TFAM protein levels are higher in conditions with enhanced oxidative capacity. The mRNA levels of TFB1M and TFB2M are influenced by endurance training, possibly suggesting a role for these factors in the regulation of exercise-induced mitochondrial biogenesis. [source]

    Thyroid fine needle aspiration: the morphological features on ThinPrep® slide preparations.

    CYTOPATHOLOGY, Issue 6 2003
    Eighty cases with histological control
    This study had several purposes: to define cytomorphological features of thyroid cells that might be modified by alcohol fixation; to optimize May-Grünwald,Giemsa (MGG) staining on ThinPrep® (TP; Cytyc Inc., Bexborough, MA, USA) slides and to compare the diagnostic accuracy of slides prepared by a liquid-based method with those obtained by conventional technique. This study included 120 cases of ultrasound-guided fine needle aspiration (FNA) of the thyroid and 55 FNAs performed on surgically resected thyroid specimens. Histological control was available in 80 cases. In the first group of 120 FNAs, a split-sample technique was used for the TP. Three screenings were performed: first, an individual screening of the conventional smears (CS) and of the TP, a second screening to compare cells observed on the TP with the histological control and a third screening to assess the previously defined diagnostic criteria. Twenty-seven TP cases (22%) were considered unsatisfactory for diagnosis compared with 10 in CS (8%). The high rate of unsatisfactory cases with TP is likely to be due to the use of the split-sample technique. The sensitivity was 94% for CS and 81% for TP. The specificity was 67% and 60% for CS and TP, respectively. Two occult papillary carcinomas were missed by both methods. As for the MGG staining, the modified technique used for TP resulted in the same quality as the standard procedure. Conversely, TP did however induce uncommon morphological features. In this study, sensitivity and specificity levels are higher for CS than for TP; the difference may be explained by the fact that the methanol fixative used for TP induces some cytological alterations, especially in oncocytic tumours and lymphocytic thyroïditis. [source]

    Comparative study: conventional cervical and ThinPrep® Pap tests in a routine clinical setting

    CYTOPATHOLOGY, Issue 4 2002
    A. Grace
    The conventional Papanicolaou smear is associated with variable false positive and false negative rates, difficulties with interpretation and high unsatisfactory and suboptimal rates. Newer fluid-based methods such as the ThinPrep® 2000 system (Cytyc Corp., Boxborough, MA) are said to overcome these difficulties. The aim of this study was to compare the conventional smear with the ThinPrep® method in a busy, routine cytology screening laboratory setting. One thousand split samples were evaluated. Using ThinPrep®, the results showed an increased sensitivity and a dramatic improvement in specimen adequacy, with a combined 17.2% reduction in ,unsatisfactory' and ,suboptimal' reports. Screening time per slide was also reduced to 3,4 min. In conclusion, we report an increase in sensitivity, a reduction in screening time and a dramatic improvement in specimen adequacy with the ThinPrep® method. [source]

    Safety of sertindole versus risperidone in schizophrenia: principal results of the sertindole cohort prospective study (SCoP)

    S. H. L. Thomas
    Thomas SHL, Drici MD, Hall GC, Crocq MA, Everitt B, Lader MH, Le Jeunne C, Naber D, Priori S, Sturkenboom M, Thibaut F, Peuskens J, Mittoux A, Tanghøj P, Toumi M, Moore ND, Mann RD. Safety of sertindole versus risperidone in schizophrenia: principal results of the sertindole cohort prospective study (SCoP) Objective:, To explore whether sertindole increases all-cause mortality or cardiac events requiring hospitalization, compared with risperidone. Method:, Multinational randomized, open-label, parallel-group study, with blinded classification of outcomes, in 9858 patients with schizophrenia. Results:, After 14147 person-years, there was no effect of treatment on overall mortality (sertindole 64, risperidone 61 deaths, Hazard Ratio (HR) = 1.12 (90% CI: 0.83, 1.50)) or cardiac events requiring hospitalization [sertindole 10, risperidone 6, HR = 1.73 (95% CI: 0.63, 4.78)]: Of these, four were considered arrhythmia-related (three sertindole, one risperidone). Cardiac mortality was higher with sertindole (Independent Safety Committee (ISC): 31 vs. 12, HR=2.84 (95% CI: 1.45, 5.55), P = 0.0022; Investigators 17 vs. 8, HR=2.13 (95% CI: 0.91, 4.98), P = 0.081). There was no significant difference in completed suicide, but fewer sertindole recipients attempted suicide (ISC: 68 vs. 78, HR=0.93 (95% CI: 0.66, 1.29), P = 0.65; Investigators: 43 vs. 65, HR=0.67 (95% CI: 0.45, 0.99), P = 0.044). Conclusion:, Sertindole did not increase all-cause mortality, but cardiac mortality was higher and suicide attempts may be lower with sertindole. [source]

    Efficacy and safety of two treatment algorithms in bipolar depression consisting of a combination of lithium, lamotrigine or placebo and paroxetine

    M. L. M. Van Der Loos
    van der Loos MLM, Mulder P, Hartong EGThM, Blom MBJ, Vergouwen AC, van Noorden MS, Timmermans MA, Vieta E, Nolen WA, for the LamLit Study Group. Efficacy and safety of two treatment algorithms in bipolar depression consisting of a combination of lithium, lamotrigine or placebo and paroxetine. Objective:, In a previous paper, we reported about the efficacy of the addition of lamotrigine to lithium in patients with bipolar depression. In the second phase of this study paroxetine was added to ongoing treatment in non-responders. Method:, Bipolar depressed patients (n = 124) treated with lithium were randomized to addition of lamotrigine or placebo. In non-responders after 8 weeks, paroxetine 20 mg was added for another 8 weeks to ongoing treatment. Results:, After 8 weeks the improvement in patients treated with lamotrigine vs. patients treated with placebo was significant. After addition of paroxetine this difference disappeared as a result of greater further improvement in the non-responders to placebo. Conclusion:, Addition of lamotrigine to lithium was found effective in bipolar depressed patients. Further addition of paroxetine in non-responders to lithium plus lamotrigine did not appear to provide additional benefit, while it appeared to do so in non-responders to lithium plus placebo. [source]

    Retinal Evaluation After 810 nm Dioderm Laser Removal of Eyelashes

    Randal T. H. Pham MD
    background. When operating hair removal lasers on the face or in the periorbital region, even with an ocular shield in place, patients often report seeing "flashing lights" each time the laser is fired. This phenomenon suggests stimulation of retinal photoreceptors and raises laser safety issues. objective. To perform retinal electrophysiologic studies to evaluate the safety of hair removal lasers in the periorbital region. methods. Five patients with severe trichiasis secondary to trachoma were studied. The 810 nm Dioderm laser (Cynosure, Inc., Chelmsford, MA) was used to treat the eyelash follicles on the lower eyelid of each patient. Cox III metal eye shields (Oculo-Plastik, Inc., Montreal, Canada) were placed behind the eyelids of both eyes during the laser procedure. Prior to irradiation, a comprehensive ophthalmic evaluation including pupillary and slit-lamp examination, funduscopy, and full-field electroretinograms (ERGs) was performed. A comprehensive ophthalmic evaluation including ERG testing was repeated 30 minutes and 3,6 months after completion of treatment. An independent blinded assessor evaluated the ERG studies. Subjective reports of laser light sensation, pain, and discomfort during and after the laser procedure were also assessed. results. There was no detectable change in slit-lamp, pupillary, or funduscopic evaluations after periorbital laser irradiation. Similarly the pre- and posttreatment ERGs were unchanged. Three patients reported seeing flashing lights during the procedure. conclusion. We found no ERG evidence of retinal damage after laser hair removal in the periorbital region, with Cox III-type ocular shields over the eyes, even when patients subjectively reported "flashing lights" during laser irradiation. [source]

    Insulin resistance is an independent correlate of increased urine albumin excretion: a cross-sectional study in Iranian Type 2 diabetic patients

    DIABETIC MEDICINE, Issue 2 2009
    A. Esteghamati
    Abstract Aims, To assess the association of insulin resistance with increased urinary albumin excretion (UAE) in a cohort of Iranian Type 2 diabetic patients. Methods, Three hundred and sixty-one men and 472 women with Type 2 diabetes were enrolled from three different outpatient clinics (Tehran, Iran) during the period 2005,2008. Patients with obstructive uropathy, severe heart failure, liver disease, cancer, autoimmune disease and macroalbuminuria were not included. Microalbuminuria (MA; defined as UAE , 30 mg/day) was found in 242 (29.1%) patients; 591 (70.9%) subjects had normoalbuminuria (UAE < 30 mg/day). Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HOMA-IR). Results, HOMA-IR index values were higher in subjects with MA than those with normoalbuminuria (P < 0.00001). Adjusted values (for age, sex and duration of diabetes) of UAE and HOMA-IR were 11.81 ± 7.51 (mg/day) and 3.30 ± 2.21 in normoalbuminuric and 75.36 ± 55.57 (mg/day) and 4.98 ± 3.22 in the MA group, respectively (P < 0.00001 for all). Multiple regression analysis showed that UAE was predicted by HOMA-IR, independently of age, duration of diagnosed diabetes, triglycerides, waist circumference, metabolic control, blood pressure and related treatments (P < 0.00001). When patients were categorized into quartiles of HOMA-IR, those of the fourth quartile (i.e. the most insulin resistant) were at a higher risk of increased UAE than other quartiles [odds ratio (OR) 3.7 (95% confidence intervals 2.7,6.2)]. Conclusions, In Iranian Type 2 diabetic patients, albuminuria was strongly associated with insulin resistance. HOMA-IR is an independent predictor of UAE. [source]

    Longitudinal study of urinary albumin excretion in young diabetic patients,-Wessex Diabetic Nephropathy Project

    DIABETIC MEDICINE, Issue 5 2001
    S. Twyman
    Summary Aims This study was established to follow changes in albumin/creatinine ratio (ACR) and to determine the prevalence and degree of progression of microalbuminuria (MA) or of clinical proteinuria (CP) in children with Type 1 diabetes. The study has investigated subjects for up to 12 years in establishing the correlation between MA and gender, age, duration of diabetes and glycated haemoglobin (HbA1c). The study has defined clinical cut-offs for MA in daytime clinic urine samples in young diabetic subjects. Methods Three hundred and sixty-one patients were involved in the study, with 221 (61.2%) having over six sets of data. Urine samples were collected at routine annual clinic visits and analysed without prior freezing for ACR. Blood samples were taken for HbA1c measurement. Data including sex, age and duration of diabetes were recorded. Results A random clinic ACR of <,4.5 mg/mmol (males) and 5.2 mg/mmol (females) creatinine was used as the ,clinical cut-off' to define the presence of MA. The presence of MA was independent of HbA1c and duration of diabetes but appeared be associated with the adolescent years (> 10 years). There was little evidence of progression from normoalbuminuria to MA, or from MA to CP. Of patients aged 10,18 years, 30.9% of males and 40.4% of females had one or more episodes of MA. Conclusions Persistent MA and random episodes of MA or CP may be associated with the adolescent years but not with duration of diabetes. Further study will reveal if the substantial increases in ACR sometimes seen during adolescence are predictive of diabetic nephropathy. Clinical cut-offs of <,4.5 and <,5.2 mg/mmol creatinine for males and females, respectively, are suggested for the interpretation of changes in ACR in random urine samples in young people with Type 1 diabetes. [source]

    Relationship between the severity of retinopathy and progression to photocoagulation in patients with Type 2 diabetes mellitus in the UKPDS (UKPDS 52)

    DIABETIC MEDICINE, Issue 3 2001
    Uk Prospective Diabetes Study (ukpds) Group
    Summary Aim to establish the degree to which the severity of retinopathy determines the risk for the need for subsequent photocoagulation in those with newly diagnosed Type 2 diabetes mellitus. Methods Of 5102 patients entered into the UK Prospective Diabetes Study (UKPDS), 3709 had good quality retinal photographs that could be graded at entry. They were followed until the end of the study or until lost to follow-up, or until they received photocoagulation. Retinopathy severity was categorized as no retinopathy, microaneurysms (MA) only in one eye, MA in both eyes or more severe retinopathy features. The risk of photocoagulation was assessed in relation to severity of retinopathy at baseline, 3 and 6 years. Results Of the 3709 patients assessed at entry to the UKPDS, 2316 had no retinopathy. Of these 0.2% needed photocoagulation at 3 years, 1.1% at 6 years and 2.6% at 9 years. Those with MA in one eye only (n = 708) were similar, with 0%, 1.9% and 4.7% needing photocoagulation by 3, 6 and 9 years, respectively. Amongst those who had more retinopathy features at entry (n = 509), 15.3% required photocoagulation by 3 years, and 31.9% by 9 years. When those without retinopathy at 6 years (n = 1579) were examined 3 and 6 years later (9 and 12 years after diagnosis), 0.1% and 1.8% required photocoagulation. Those with more severe retinopathy (n = 775) needed earlier treatment, 6.6% after 3 years and 13.3% after 9 years. The commonest indication for laser therapy was maculopathy, but those with more severe retinopathy were more likely to be treated for proliferative retinopathy and to need both eyes treated. Conclusion Few type 2 diabetic patients without retinopathy progress to photocoagulation in the following 3,6 years, while patients with more severe retinopathy lesions need to be monitored closely. [source]

    Comparison of conventional Papanicolaou smears and fluid-based, thin-layer cytology with colposcopic biopsy control in central Italy: A consecutive sampling study of 461 cases

    Siavash Rahimi M.D.
    Abstract The aim of this study was to compare the cytologic diagnosis and specimen adequacy of conventional Papanicolaou (CP) and fluid-based, thin-layer [ThinPrep (TP), Cytyc, Boxborough, MA] cervical cytology in a population from central Italy. CP and TP samples were collected simultaneously using a consecutive sampling method on women presenting for cervical screening. Colposcopy was performed as clinically indicated, and biopsy results were compared with cytologic diagnoses. Among the 461 patients included in the study, 413 were negative at both CP and TP, 9 had unsatisfactory results at both tests and 39 patients presented abnormal results at CP, TP or both. Cohen's Kappa was 0.77 showing good agreement between CP and TP test results. Histological data were available for 20 (51.28%) of the 39 patients with at least one positive test. Among the 13 patients with HSIL at histology, 7 had HSIL at CP (sensitivity 53.85%) and 5 at TP (sensitivity 38.46%). For all three patients with squamous cell carcinoma (SCC) at histology, CP and TP had shown the same diagnosis (sensitivity 100%). The positive predictive values were 33.33% for CP and 25.0% for TP regarding the LSIL diagnosis and 100% for both CP and TP regarding HSIL and SCC diagnoses. Our results may be influenced by the consecutive sampling procedure. Diagn. Cytopathol. 2009. © 2008 Wiley-Liss, Inc. [source]

    Rapid review of liquid-based smears as a quality control measure

    Sheryl Henderson M.Med.Sc.(Cytol.)
    Abstract The objective of this study was to investigate the effectiveness of a standardized method of rapid review (RR) of monolayer preparations for the identification of abnormalities, the presence of an endocervical component and infectious agents. A total of 200 ThinPrep (Cytyc, Boxborough, MA) slides representing the spectrum of abnormalities commonly encountered in cervical/vaginal cytologic specimens was retrieved from archive. The study set comprised 129 cases within normal limits (WNL); 36 low-grade epithelial abnormalities (LGEA); 28 high-grade epithelial abnormalities (HGEA), including 2 endocervical adenocarcinomas in situ (AIS) and 7 carcinomas. Eighteen false negative (FN) cases were also included for study. Originally missed on initial review, these cases were found to be abnormal on quality control review (17 LGEA; 1 AIS). Commonly encountered infectious agents were represented and included Candida albicans, Trichomonas vaginalis, herpes simplex virus, and Actinomyces. The slides were reviewed using a standardized method of RR (turret technique, for 60 sec) by three experienced screeners masked to the original reference diagnosis. Median sensitivity for LGEA was 70% (range, 67,72%); HGEA, 69% (range, 54,80%); and FN, 65% (range, 56,78%). Specificity remained high, median specificity for LGEA was 95%; HGEA, 97%; and FN, 100%. There was no significant overcalling of any diagnostic category. The chi-square test at P < 0.05 showed no significant difference between RR and full manual rescreen of the ThinPrep smears in this study. While no statistical difference was proven, the sensitivity measurements for all categories of abnormality were moderate due to the high proportion of atypical cases included into the study set. Abnormalities on the monolayer preparations frequently displayed fewer, smaller groups of disaggregated cells with rounded cytoplasmic outlines that were difficult to discern on RR. Interobserver variation was noted. Monolayers with a paucity of diagnostic cells and those displaying subtle nuclear atypia were often overlooked. Diagn. Cytopathol. 2004;31:141,146. © 2004 Wiley-Liss, Inc. [source]

    Overdose deaths following previous non-fatal heroin overdose: Record linkage of ambulance attendance and death registry data

    Abstract Introduction and Aims. Experiencing previous non-fatal overdoses have been identified as a predictor of subsequent non-fatal overdoses; however, few studies have investigated the association between previous non-fatal overdose experiences and overdose mortality. We examined overdose mortality among injecting drug users who had previously been attended by an ambulance for a non-fatal heroin overdose. Design and Methods. Using a retrospective cohort design, we linked data on non-fatal heroin overdose cases obtained from ambulance attendance records in Melbourne, Australia over a 5-year period (2000,2005) with a national death register. Results. 4884 people who were attended by ambulance for a non-fatal heroin overdose were identified. One hundred and sixty-four overdose deaths occurred among this cohort, with an average overdose mortality rate of 1.20 per 100 person-years (95% CI, 1.03,1.40). Mortality rate decreased 10-fold after 2000 coinciding with widely reported declines in heroin availability. Being male, of older age (>35 years) and having been attended multiple times for previous non-fatal overdoses were associated with increased mortality risk. Discussion and Conclusions. As the first to show a direct association between non-fatal overdose and subsequent overdose mortality, this study has important implications for the prevention of overdose mortality. This study also shows the profound effect of macro-level heroin market dynamics on overdose mortality.[Stoové MA, Dietze PM, Jolley D. Overdose deaths following previous non-fatal heroin overdose: Record linkage of ambulance attendance and death registry data. Drug Alcohol Rev 2009;28:347,352] [source]

    Withdrawal symptoms in abstinent methamphetamine-dependent subjects

    ADDICTION, Issue 10 2010
    Todd Zorick
    ABSTRACT Aims Withdrawal symptoms have been linked to a propensity for relapse to drug abuse. Inasmuch as this association applies to methamphetamine (MA) abuse, an understanding of the course of MA withdrawal symptoms may help to direct treatment for MA dependence. Previous studies of symptoms manifested during abstinence from MA have been limited in size and scope. We asked (i) whether debilitating psychological and/or physical symptoms appear during the first several weeks of MA abstinence, (ii) how craving for MA evolves and (iii) whether psychiatric symptoms (e.g. depression, psychosis) persist beyond a month of abstinence. Design A study of MA-dependent participants, who initiated and maintained abstinence from the drug for up to 5 weeks, compared to a matched healthy comparison group. Setting In-patient research hospital ward (MA-dependent subjects) and out-patient (comparison subjects). Participants Fifty-six MA-dependent and eighty-nine comparison subjects. Measurements Rater-assessed MA withdrawal questionnaire and self-report assessment of craving (MA-dependent subjects) and self-report assessment of psychiatric symptoms (both groups). Findings At study entry, MA-dependent subjects exhibited a wide range in severity of depressive symptoms, with the average score at a mild,moderate level of severity. Symptoms of psychosis were also prevalent. While depressive and psychotic symptoms largely resolved within a week of abstinence, craving did not decrease significantly from the time of initiating abstinence until the second week, and then continued at a reduced level to the fifth week. Conclusions Depressive and psychotic symptoms accompany acute withdrawal from methamphetamine but resolve within 1 week. Craving is also present and lasts at least 5 weeks. [source]

    New Annular Tissue Doppler Markers of Pulmonary Hypertension

    ECHOCARDIOGRAPHY, Issue 8 2010
    Angel López-Candales M.D., F.A.C.C., F.A.S.E.
    Background: Tissue Doppler imaging (TDI) of mitral (MA) and tricuspid annulus (TA) events characterizes systolic and diastolic properties of each respective ventricle. However, the effect of chronic pulmonary hypertension (cPH) on these TDI annular events has not been well described. Methods: Measurements of right ventricular (RV) performance with TDI of the lateral mitral and tricuspid annuli, to measure isovolumic contraction (IVC) and systolic (S) signals were recorded from 50 individuals without PH and from 50 patients with cPH. To avoid confounding variables, all patients had normal left ventricular ejection fraction and were in normal sinus rhythm at the time of the examination. Results: As expected, markers of RV systolic performance were markedly reduced while LV systolic function remained largely unaffected in cPH patients when compared to patients without PH. TDI interrogation of the MA revealed lengthening of the time interval between IVC and systolic signal (70 ± 17 msec) when compared to individuals without PH (43 ± 8 msec; P < 0.0001). In contrast, cPH markedly shortened the time interval between IVC and the TA systolic signal (34 ± 12 msec) when compared to individuals without PH (65 ± 17 msec; P < 0.0001). Conclusions: cPH lengthens time interval between the IVC and the MA systolic signal while shortening this same interval when the TA is interrogated with TDI; reflecting the potential influence that cPH exerts in biventricular performance. Whether measuring these intervals be routinely used in the follow-up of cPH patients will require further study. (Echocardiography 2010;27:969-976) [source]

    Comparison of Tissue Doppler Velocities Obtained by Different Types of Echocardiography Systems: Are They Compatible?

    ECHOCARDIOGRAPHY, Issue 3 2010
    Mónika Dénes M.D.
    Background: Both systolic and diastolic tissue Doppler (TD) velocities have an important diagnostic and prognostic role in cardiology. We aimed to compare TD velocities between two different echocardiography systems. Patients: Thirty-one consecutive patients (mean age: 65.2 ± 17.5 years; 12 males) were enrolled. Methods: Systolic (Sa), early (Ea), and late (Aa) diastolic velocities were measured by TD at the lateral mitral annulus by a Sonos 2000 (Hewlett-Packard, Andover, MA, USA) and a Philips iE33 system. The E/Ea ratio was calculated. Results: Ea, Aa, and Sa velocities were higher when measured by the Sonos system (Ea: 13.2 ± 4.1 cm/s vs. 8.3 ± 3.6 cm/s; Aa: 14.8 ± 3.8 cm/s vs. 9.3 ± 2.3 cm/s; Sa: 15.2 ± 3.6 cm/s vs. 8.4 ± 2.0 cm/s; P < 0.0001 all). A significant correlation was found in Ea and in Ea/Aa (r = 0.84 and r = 0.85 resp; P < 0.0001 for both), and a weaker in Aa (r = 0.43; P = 0.02) between the machines. The Bland-Altman analysis showed broad limits of agreement between the measurements for Ea, Aa, and Sa (mean difference: 4.95 cm/s; 5.52 cm/s; 6.73 cm/s, respectively; limits: 0.64,9.25 cm/s; ,1.39,12.39 cm/s; ,0.37,13.83 cm/s, respectively). An E/Ea ratio >5.6 by the Sonos system showed 75% sensitivity and 79% specificity for elevated left ventricular filling pressure, defined as E/Ea >10 by the reference Philips system. Conclusions: Although diastolic TD velocities had excellent correlations between the two machines, there was a systematic overestimation by the Sonos system. Since the limits of agreement do not allow replacing the measurements, we suggest using the same echocardiographic equipment at patient follow-up. (Echocardiography 2010;27:230-235) [source]

    Local Dysfunction and Asymmetrical Deformation of Mitral Annular Geometry in Ischemic Mitral Regurgitation: A Novel Computerized 3D Echocardiographic Analysis

    ECHOCARDIOGRAPHY, Issue 4 2008
    Masao Daimon M.D.
    Objective: Most studies of the pathogenesis of functional mitral regurgitation (MR) have focused on alterations in ventricular function and geometry. We used a novel 3D echocardiographic method to assess abnormalities in mitral annular (MA) geometry and motion in patients with ischemic MR (IMR) and compared these data to those obtained from normal subjects and from patients with MR caused by dilated cardiomyopathy (DMR). Methods: Real time 3D echo was performed in 12 normal subjects, 25 with IMR, and 14 with DMR. Eight points along the saddle-shaped MA were identified using our software at systole and diastole. From these eight points, four annular diameters at each cardiac phase were determined. Annular motion was assessed by measuring local displacement (LD) of a given point between systole and diastole. Results: Annular motion was different between groups: IMR had smaller LD in posterior MA segments than did normals (2.6 ± 1.1 vs 4.8 ± 1.9 mm, P < 0.01), while DMR had globally reduced LD. In IMR systolic MA dilatation was striking in the anterior,posterior (diameter; IMR vs controls, 28.3 ± 3.5 vs 22.5 ± 2.2 mm, P< 0.05) and anterolateral,posteromedial (31.7 ± 3.5 vs 25.1 ± 2.2 mm, P < 0.05) directions; in IMR, systolic MA diameters in these two directions correlated with MR severity(P = 0.02). MA dilatation occurred globally in DMR. Conclusion: This novel 3D echo method demonstrated that MA motion and dilatation were asymmetric in IMR and symmetric in DMR. These differences in MA geometry and motion may aid in the development of distinct new therapies for IMR and DMR. [source]

    Real Time Three-Dimensional Echocardiography Evaluation of Mitral Annular Characteristics in Patients with Myocardial Hypertrophy

    ECHOCARDIOGRAPHY, Issue 4 2008
    Fatih Yalçin M.D.
    It has been shown that systolic excursion of the mitral annulus (MA) correlates well with left ventricular (LV) systolic function. Evaluation of the complicated shape and dynamics of the mitral annulus, however, may require rigorous methodology. The aim of this study was to investigate differences in MA motion between hypertrophic cardiomyopathy (HCM) and left ventricular hypertrophy (LVH) patients due to hypertension or aortic stenosis using real time three-dimensional echocardiography (RT3DE). We studied 10 HCM, 10 LVH, and 10 controls. Mean MA area changes between early and late systole were 9.5 ± 4.3% in HCM, 26 ± 15% in LVH and 19 ± 10% in normal controls. MA apicobasal motion was 5.8 ± 4 mm in HCM, 11 ± 4 mm in LVH, and 13.6 ± 6 mm in normal controls. RT3DE with digital reconstruction of MA accurately display complicated MA geometry and dynamics during a cardiac cycle. Annular function in LVH was similar to that of the normal group while annular apicobasal motion and area changes were reduced in HCM. [source]

    Reference Values Describing the Normal Mitral Valve and the Position of the Papillary Muscles

    ECHOCARDIOGRAPHY, Issue 7 2007
    Petrus Nordblom M.Sc.
    In patients with functional mitral regurgitation (MR), the principal mechanisms are insufficient coaptation due to dilatation of the mitral annulus (MA), global ventricular dysfunction with tethering of leaflets, or restricted leaflet motion with incorrect apposition due to regional ventricular dysfunction and displacement of the papillary muscles (PMs). These different entities often coexist and for this reason, knowledge of the normal reference values describing the shape and size of the MA and the position of the PMs is essential. In the present study, we describe the MA dimensions and the position of the PMs in a group of normal individuals (n = 38, 60% women, age [mean ± SD] 51 ± 9 years and BSA 1.83 ± 0.16 m2) investigated with transthoracic echocardiography. The anteroposterior dimension (AP) of the ellipse-shaped MA was measured in a parasternal long axis, while the distance from the posteromedial (PoM) to the anterolateral (AL) commissure was measured in a parasternal short axis (CC). The annular area was calculated assuming elliptic geometry. The MA shape was described by the ratios AP/CC and AP/length of the anterior leaflet. The PMs' position was described by the following distances: (a) from the MA to the tip of the PoM and AL, PMs measured in a modified two-chamber view where both PMs could be identified, (b) the interpapillary distance, and (c) the tethering distance from the tip of the PM to the contralateral MA. These data on the normal mitral valve morphology should provide useful information when assessing the underlying mechanism of functional MR. [source]


    ECHOCARDIOGRAPHY, Issue 1 2004
    E. Ereminien
    Aim: The aim of our study was to establish the anatomical-functional mechanisms of ischemic mitral regurgitation (MR) and to analyse its impact on late results after mitral valve (MV) reconstructive surgery. Methods: The study included 53 patients with ischemic MR, who underwent CABG and MV repair. MV surgery consisted of subvalvular apparatus repair and/or annuloplasty. 2D Doppler investigations performed pre-, 10,14 days, and 12 months after surgery included evaluation of MV and left ventricular (LV) geometry and function. Results: Analysis of the mechanisms of ischemic MR permitted dividing patients into two groups: group 1,29 patients with inferobasal scar and posterior papillary muscle (PM) displacement, including 22 patients with PM infarction and 7 patients without it, and group 2,24 patients with isolated mitral annulus (MA) dilation. In the case of PM infarction two different mechanisms of MR were stated: (a) P3 restriction and A3 prolapse due to chordal tethering, (b) A3 P3 (commissural) prolapse due to chordal papillary elongation. Preoperatively LV geometry and function were better preserved in group 1 and late MV repair results were better versus (vs.) group 2: LV end-systolic diameter index decreased from 22.9 ± 3.1 mm/m2 to 20.9 ± 3.6 mm/m2 at 1 year, p < 0.05, LV ejection fraction increased from 34.9 ± 8.4 to 41.8 ± 8.1%, respectively, p < 0.05. No significant changes in LV geometry and function were noted in group 2. Conclusions: The underlying mechanism of ischemic MR has an impact on MV repair results. In patients with MR due to posterobasal infarction MV repair resulted in more favorable postoperative effect-marked improvement in LV geometry and function late after surgery versus MR due to isolated MA dilation. [source]

    Health outcomes associated with methamphetamine use among young people: a systematic review

    ADDICTION, Issue 6 2010
    Brandon D. L. Marshall
    ABSTRACT Objectives Methamphetamine (MA) use among young people is of significant social, economic and public health concern to affected communities and policy makers. While responses have focused upon various perceived severe harms of MA use, effective public health interventions require a strong scientific evidence base. Methods We conducted a systematic review to identify scientific studies investigating health outcomes associated with MA use among young people aged 10,24 years. The International Classification of Diseases (ICD-10) was used to categorize outcomes and determine the level of evidence for each series of harms. Results We identified 47 eligible studies for review. Consistent associations were observed between MA use and several mental health outcomes, including depression, suicidal ideation and psychosis. Suicide and overdose appear to be significant sources of morbidity and mortality among young MA users. Evidence for a strong association between MA use and increased risk of human immunodeficiency virus (HIV) and other sexually transmitted infections is equivocal. Finally, we identified only weak evidence of an association between MA use and dental diseases among young people. Conclusions Available evidence indicates a consistent relationship between MA use and mental health outcomes (e.g. depression, psychosis) and an increased risk of mortality due to suicide and overdose. We found insufficient evidence of an association between MA use and other previously cited harms, including infectious diseases and dental outcomes. As such, future research of higher methodological quality is required to further investigate possible associations. Current interventions should focus attention upon MA-related health outcomes for which sound scientific evidence is available. [source]

    Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach

    M. A. Stapanian
    Stapanian MA, Witzel LD, Cook A. Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach. Ecology of Freshwater Fish 2010: 19: 326,337. Published 2010. This article is a US Government work and is in the public domain in the USA Abstract,,, World-wide, many burbot Lota lota (L.) populations have been extirpated or are otherwise in need of conservation measures. By contrast, burbot made a dramatic recovery in Lake Erie during 1993,2001 but declined during 2002,2007, due in part to a sharp decrease in recruitment. We used Akaike's Information Criterion to evaluate 129 linear regression models that included all combinations of one to seven ecological indices as predictors of burbot recruitment. Two models were substantially supported by the data: (i) the number of days in which water temperatures were within optimal ranges for burbot spawning and development combined with biomass of yearling and older (YAO) yellow perch Perca flavescens (Mitchill); and (ii) biomass of YAO yellow perch. Warmer winter water temperatures and increases in yellow perch biomass were associated with decreases in burbot recruitment. Continued warm winter water temperatures could result in declines in burbot recruitment, particularly in the southern part of the species' range. [source]

    On the Use of the Moving Average Trading Rule to Test for Weak Form Efficiency in Capital Markets

    ECONOMIC NOTES, Issue 2 2008
    Alexandros E. Milionis
    The examination for the possible existence of predictive power in the moving average trading rule has been used extensively to test the hypothesis of weak form market efficiency in capital markets. This work focuses mainly on the study of the variation of the moving average (MA) trading rule performance as a function of the length of the longer MA. Empirical analysis of daily data from NYSE and the Athens Stock Exchange reveal high variability of the performance of the MA trading rule as a function of the MA length and on some occasions the series of successive trading rule total returns is non-stationary. These findings have direct implications in weak form market efficiency testing. Indeed, given this high variability of the performance of the MA trading rule, by just finding out that trading rules with some specific combinations of MA lengths can or cannot beat the market, as is the case in most of the published work thus far, is not enough evidence for or against the existence of weak form market efficiency. Results also show that on average in about three out of four cases trading rule signals are false, a fact that leaves a lot of space for improved trading rule performance if trading rule signals are combined with other information (e.g. filters, or volume of trade). Finally, some evidence of enhanced trading rule performance for the shorter MA lengths was found. This enhanced performance is partly attributed to the higher probability that a trading rule signal is not a whipsaw, as well as to the larger number of days out-of-the-market which are associated with shorter MA lengths. [source]

    Photobleaching-based flow measurement in a commercial capillary electrophoresis chip instrument

    ELECTROPHORESIS, Issue 6 2008
    Guiren R. Wang Professor
    Abstract For microfluidic analytical instruments, a facile, fast, and accurate instrument test is highly demanded. The test includes the quantitative verification of the relationship between pressure drop and flow velocity for the hydrodynamic pump, between the electric voltage and electroosmotic flow (EOF) for the high-voltage supply, and the chip quality. The key point for the test is the measurement of the flow velocity. However, most currently available velocimetries cannot be directly used without any instrumental modification or adding extra instruments. We applied a recently developed Laser Induced Fluorescence Photobleaching Anemometer (LIFPA) for the instrument test through measuring fluid flow velocity in a microfluidic instrument with optical measurement without any modification and extra instrument. We have successfully used the method to test Caliper HTS 250 System from Caliper Life Sciences (Hopkinton, MA) with its own light source and detector. The experimental result demonstrates that this single-point method of measuring flow velocity can be easily used for accurate test of a microfluidic instrument in less than 10,min at extremely low cost without any modification and extra instrument. [source]

    On-line sample preconcentration with chemical derivatization of bacterial biomarkers by capillary electrophoresis: A dual strategy for integrating sample pretreatment with chemical analysis

    ELECTROPHORESIS, Issue 21 2005
    Adam S. Ptolemy
    Abstract Simple, selective yet sensitive methods to quantify low-abundance bacterial biomarkers derived from complex samples are required in clinical, biological, and environmental applications. In this report, a new strategy to integrate sample pretreatment with chemical analysis is investigated using on-line preconcentration with chemical derivatization by CE and UV detection. Single-step enantioselective analysis of muramic acid (MA) and diaminopimelic acid (DAP) was achieved by CE via sample enrichment by dynamic pH junction with ortho -phthalaldehyde/N -acetyl- L -cysteine labeling directly in-capillary. The optimized method resulted in up to a 100-fold enhancement in concentration sensitivity compared to conventional off-line derivatization procedures. The method was also applied toward the detection of micromolar levels of MA and DAP excreted in the extracellular medium of Escherichia coli bacterial cell cultures. On-line preconcentration with chemical derivatization by CE represents a unique approach for conducting rapid, sensitive, and high-throughput analyses of other classes of amino acid and amino sugar metabolites with reduced sample handling, where the capillary functions simultaneously as a concentrator, microreactor, and chiral selector. [source]

    Loss of diversity of ammonia-oxidizing bacteria correlates with increasing salinity in an estuary system

    Anne E. Bernhard
    Summary Ammonia-oxidizing bacteria (AOB) play an important role in nitrogen cycling in estuaries, but little is known about AOB diversity, distribution and activity in relation to the chemical and physical changes encountered in estuary systems. Although estuarine salinity gradients are well recognized to influence microbial community structure, few studies have examined the influence of varying salinity on the diversity and stability of AOB populations. To investigate these relationships, we collected sediment samples from low-, mid- and high-salinity sites in Plum Island Sound estuary, MA, during spring and late summer over 3 years. Ammonia-oxidizing bacteria distribution and diversity were assessed by terminal restriction fragment length polymorphism (TRFLP) analysis of the ammonia monooxygenase (amoA) gene, and fragments were identified by screening amoA clone libraries constructed from each site. Most striking was the stability and low diversity of the AOB community at the high-salinity site, showing little variability over 3 years. Ammonia-oxidizing bacteria at the high-salinity site were not closely related to any cultured AOB, but were most similar to Nitrosospira spp. Ammonia-oxidizing bacteria at the mid- and low-salinity sites were distributed among Nitrosospira- like sequences and sequences related to Nitrosomonas ureae/oligotropha and Nitrosomonas sp. Nm143. Our study suggests that salinity is a strong environmental control on AOB diversity and distribution in this estuary. [source]