bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic flight stability in the desert locustSchistocerca gregaria
Authors: Taylor Graham K. , Thomas Adrian L. R. 
Published: July 2003

SUMMARYHere we provide the first formal quantitative analysis of dynamic stability in a flying animal. By measuring the longitudinal static stability derivatives and mass distribution of desert locusts Schistocerca gregaria, we find that their static stability and static control responses are insufficient to provide asymptotic longitudinal dynamic stability unless they are sensitive to pitch attitude (measured with respect to an inertial or earth-fixed frame)as well as aerodynamic incidence (measured relative to the direction of flight). We find no evidence for a `constant-lift reaction', previously supposed to keep lift production constant over a range of body angles, and show that such a reaction would be inconsequential because locusts can potentially correct for pitch disturbances within a single wingbeat. The static stability derivatives identify three natural longitudinal modes of motion: one stable subsidence mode, one unstable divergence mode, and one stable oscillatory mode (which is present with or without pitch attitude control). The latter is identified with the short period mode of aircraft, and shown to consist of rapid pitch oscillations with negligible changes in forward speed. The frequency of the short period mode (approx. 10 Hz) is only half the wingbeat frequency (approx. 22 Hz), so the mode would become coupled with the flapping cycle without adequate damping. Pitch rate damping is shown to be highly effective for this purpose — especially at the small scales associated with insect flight — and may be essential in stabilising locust flight. Although having a short period mode frequency close to the wingbeat frequency risks coupling, it is essential for control inputs made at the level of a single wingbeat to be effective. This is identified as a general constraint on flight control in flying animals.
Comparative studies of high performance swimming in sharks II. Metabolic biochemistry of locomotor and myocardial muscle in endothermic and ectothermic sharks
Authors: Bernal D. , Smith D. , Lopez G. , Weitz D. , Grimminger T. , Dickson K. , Graham J. B. 
Published: July 2003

SUMMARYMetabolic enzyme activities in red (RM) and white (WM) myotomal muscle and in the heart ventricle (HV) were compared in two lamnid sharks (shortfin mako and salmon shark), the common thresher shark and several other actively swimming shark species. The metabolic enzymes measured were citrate synthase(CS), an index of aerobic capacity, and lactate dehydrogenase (LDH), an index of anaerobic capacity. WM creatine phosphokinase (CPK) activity, an index of rapid ATP production during burst swimming, was also quantified. Enzyme activities in RM, WM and HV were similar in the two lamnid species. Interspecific comparisons of enzyme activities at a common reference temperature (20°C) show no significant differences in RM CS activity but higher CS activity in the WM and HV of the lamnid sharks compared with the other species. For the other enzymes, activities in lamnids overlapped with those of other shark species. Comparison of the HV spongy and compact myocardial layers in mako, salmon and thresher sharks reveals a significantly greater spongy CS activity in all three species but no differences in LDH activity. Adjustment of enzyme activities to in vivo RM and WM temperatures in the endothermic lamnids elevates CS and LDH in both tissues relative to the ectothermic sharks. Thus, through its enhancement of both RM and WM enzyme activity, endothermy may be an important determinant of energy supply for sustained and burst swimming in the lamnids. Although lamnid WM is differentially warmed as a result of RM endothermy, regional differences in WM CS and LDH activities and thermal sensitivities (Q10 values) were not found. The general pattern of the endothermic myotomal and ectothermic HV muscle metabolic enzyme activities in the endothermic lamnids relative to other active, ectothermic sharks parallels the general pattern demonstrated for the endothermic tunas relative to their ectothermic sister species. However, the activities of all enzymes measured are lower in lamnids than in tunas. Relative to lamnids, the presence of lower WM enzyme activities in the thresher shark (which is in the same order as the lamnids, has an RM morphology similar to that of the mako and salmon sharks and may be endothermic) suggests that other factors, such as behavior and swimming pattern, also affect shark myotomal organization and metabolic function.
Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative
Authors: Bossuyt Patrick M. , Reitsma Johannes B. , Bruns David E. , Gatsonis Constantine A. , Glasziou Paul P. , Irwig Les M. , Lijmer Jeroen G. , Moher David , Rennie Drummond , de Vet Henrica C.W. 
Published: July 2003

Background: To improve the accuracy and completeness of reporting of studies of diagnostic accuracy in order to allow readers to assess the potential for bias in a study and to evaluate the generalizability of its results. Methods: The Standards for Reporting of Diagnostic Accuracy (STARD) steering committee searched the literature to identify publications on the appropriate conduct and reporting of diagnostic studies and extracted potential items into an extensive list. Researchers, editors and members of professional organizations shortened this list during a 2-day consensus meeting with the goal of developing a checklist and a generic flow diagram for studies of diagnostic accuracy. Results: The search for published guidelines regarding diagnostic research yielded 33 previously published checklists, from which we extracted a list of 75 potential items. At the consensus meeting, participants shortened the list to 25 items, using evidence on bias whenever available. A prototypical flow diagram provides information about the method of patient recruitment, the order of test execution and the numbers of patients undergoing the test under evaluation, the reference standard or both. Conclusions: Evaluation of research depends on complete and accurate reporting. If medical journals adopt the checklist and the flow diagram, the quality of reporting of studies of diagnostic accuracy should improve to the advantage of the clinicians, researchers, reviewers, journals and the public.
Cystatin C for estimation of glomerular filtration rate in patients with spinal cord injury
Authors: Jenkins Margaret A. , Brown Douglas J. , Ierino Francesco L. , Ratnaike Sujiva I. 
Published: July 2003

Background: Serum creatinine is not a satisfactory marker of glomerular filtration rate (GFR) in patients with spinal cord injury (SCI) who have varying degrees of muscle atrophy. In contrast to serum creatinine, serum cystatin C, a 13-kDa protein, is not affected by muscle mass and is therefore potentially a useful marker of GFR in patients with SCI. In addition, cystatin C is not dependent on sex or age and is not secreted by the renal tubule. Aim: We assessed serum cystatin C as a surrogate marker of GFR in SCI patients. Methods: Cystatin C was analysed using a particle-enhanced immunonephelometric assay (Dade Behring) in serum samples sent for routine measurement of creatinine (64 patients) and creatinine clearance (27 patients) from patients in the Spinal Unit of the Austin Health. We compared these results with serum cystatin C of 57 non-SCI patients who had had a creatinine clearance measurement during the study period. Results: In patients with SCI, the reciprocal of cystatin C had a stronger correlation (r = 0·48, P<0·01) with creatinine clearance than the reciprocal of serum creatinine (r = 0·25, P<0·19). Further, the value of serum creatinine was much lower for a given creatinine clearance in SCI patients than in non-SCI patients; the serum cystatin C concentrations were equivalent. Conclusion: The serum cystatin C is a convenient and more reliable surrogate marker of GFR than serum creatinine and will enable early detection of renal impairment. We need to confirm this finding with a larger study, including comparison with an accepted gold standard for GFR.
Diagnostic value of adenosine deaminase in tuberculous pleural effusion: a meta-analysis
Authors: Goto Masashi , Noguchi Yoshinori , Koyama Hiroshi , Hira Kenji , Shimbo Takuro , Fukui Tsuguya 
Published: July 2003

Background: Many studies have investigated the usefulness of adenosine deaminase activity (ADA) in pleural fluid for the early diagnosis of tuberculous pleurisy. To summarize the diagnostic characteristics of ADA we undertook a meta-analysis using a summary receiver operating characteristic (SROC) curve method. Methods: Data sources were MEDLINE (1966-1999), the Cochrane Library and bibliographies of review and original articles. Studies were included if the absolute numbers of true positive, false negative, true negative and false positive observations were available or could be derived from the data presented; gold standards were described explicitly; and the criteria for a positive ADA result were reported. We constructed an SROC curve based on these extracted data to estimate the test characteristics. Results: Forty articles were available for analysis. The gold standards used were pleural biopsy histology, microbiological examination of pleural fluid, pleural biopsy and sputum and the patient's clinical course or combinations of these. The sensitivity of ADA reported in the articles ranged from 47·1% to 100% and the specificity from 50·0% to 100%. The summary measure of test characteristics derived from the SROC curve was 92·2% for both sensitivity and specificity. Conclusions: The test performance of ADA in tuberculous pleural effusion is reasonably good. Measurement of pleural ADA is thus likely to be a useful diagnostic tool for tuberculous pleurisy.
Apolipoprotein E gene polymorphisms in patients with premature myocardial infarction: a case-controlled study in Asian Indians in North India
Authors: Kumar Prabhat , Luthra Kalpana , Dwivedi Manjari , Behl Vinay K , Pandey Ravinder M. , Misra Anoop 
Published: July 2003

Objectives: Several factors, including abdominal obesity, insulin resistance, diabetes mellitus and low levels of high-density lipoprotein cholesterol have been implicated in the high prevalence and early onset of coronary heart disease in Asian Indians. However, there are no reports regarding the role of apolipoprotein E (apo E) gene polymorphisms in premature myocardial infarction (MI) in this population. This study aimed to study the role of apo E gene polymorphisms in premature MI patients and their relation to serum lipid levels. Design and methods: Apo E gene polymorphisms were analysed in 35 patients with MI aged <40 years and in 45 age- and sex-matched controls using polymerase chain reaction-restriction fragment length polymorphism. Levels of serum lipids were measured in addition to the evaluation of conventional risk factors. Results: Higher frequencies of the apo E4 allele (P<0·0001) and of genotypes E3/E4 (P<0·005) and E4/E4 (P<0·005) were recorded in the premature MI group compared with the controls. Multivariate regression analysis revealed that, after adjusting for other covariates, individuals with the E4 allele were at ~46 times higher odds to develop premature MI compared with individuals without the E4 allele [adjusted odds ratio, OR (95% confidence interval, CI): 45·7 (4·9-421·3)]. Among conventional risk factors, higher risk was observed in those having dyslipidaemia [OR (95% CI): 8·7 (0·9-86·6)] and those with a high waist : hip ratio [OR (95% CI): 5·6 (1·4-21·2)]. Conclusion: Based on the robust association, the apo E4 allele should be considered as an independent risk factor for premature MI in Asian Indians.
Genetic polymorphism of thiopurine S-methyltransferase in Argentina
Authors: Laróvere L. E. , de Kremer R. Dodelson , Lambooy L. H. J. , De Abreu R. A. 
Published: July 2003

Background: Thiopurine methyltransferase (TPMT) catalyses the S-methylation of 6-thiopurine drugs, which are commonly used in the treatment of autoimmune diseases, leukaemia and organ transplantation. TPMT activity is polymorphic as a result of gene mutations. Ethnic variations in phenotype and genotype have been identified in previous population studies, but no information was available within Latin-American populations. Aim: To establish the genetic polymorphism of TPMT in an Argentine population. Methods: TPMT enzymatic activity of 147 healthy Argentine subjects was measured using a high-performance liquid chromatography method. The genotyping assay for nine defective alleles (TPMT*2 - *8) was based on restriction fragment length polymorphism polymerase chain reaction and allele-specific polymerase chain reaction methods. Results: All subjects had detectable TPMT activity. Twelve individuals with low to intermediate activity were heterozygous for one of the mutant alleles: nine were TPMT*1/*3A, two TPMT*1/*2 and one TPMT*1/*4. All examined subjects with normal activity had wild-type genotype (TPMT*1/*1). Conclusion: Variant TPMT alleles were present in 8·2% of the examined subjects, which is in accordance with other studies. The frequency of TPMT*3A, TPMT*2 and TPMT*4 was 3·1%, 0·7% and 0·3%, respectively. TPMT*3A was the most prevalent allele, which is in accordance with results from Caucasian populations. This study provides the first analysis of TPMT activity and allele frequency distribution in Argentina, South America.
Urinary free deoxypyridinoline excretion in lactating and non-lactating Arabic women of the United Arab Emirates
Authors: Miller C. J. , Dunn E. V. , Thomas E. J. , Sankarankutty M. 
Published: July 2003

Background: This study aimed to measure urinary free deoxypyridinoline (Dpd) excretion in non-lactating and lactating Arabic women of the United Arab Emirates. Methods: Morning urine specimens were obtained from 679 non-pregnant, non-lactating women and 268 lactating women. Commercial enzyme-linked immunoassay kits were used for urinary free Dpd determinations. Results: For the non-lactating women, the mean urinary free Dpd excretion was 9·20 nmol/mmol creatinine (95% confidence interval: 8·82-9·59). This result was significantly higher than those reported elsewhere. There was a trend towards lower Dpd excretion with increasing age (ANOVA test of linearity P<0·05). Urinary free Dpd in lactating women was 9·92 (9·33-10·5); this was not significantly different from that of non-lactating women (P=0·052). Dpd excretion was higher in the first month post-partum, with a significant trend towards diminishing levels thereafter, returning to non-lactating levels by 9 months post-partum (ANOVA test for linearity P<0·005). Conclusion: Dpd excretion in UAE Arabic women aged 20-44 years was higher than in other groups. This could be due to ethnicity or vitamin D status.
Evaluation of two new high-sensitivity methods for C-reactive protein
Authors: Rothkrantz-Kos Snjezana , Bekers Otto , Gubbels Armand , Drent Marjolein , Schmitz Maria P. J. , van Dieijen-Visser Marja P. 
Published: July 2003

Background: The implementation of a high-sensitivity C-reactive protein (hs-CRP) assay as a routine laboratory parameter may be necessary. It would be most practical to use one CRP method giving reliable results for the whole concentration range. We report here the evaluation of two new hs-CRP methods, which cover both the low and the high concentration ranges. Methods: The BN ProSpec hs-CRP (Dade Behring) and Synchron LX 201 PRO hs-CRP methods were compared with the existing hs-CRP IMMAGE1 method (taken as a reference) and, for the high concentration range, also with the routine Synchron LX1 20 CRP method (all from Beckman). Agreement among methods was examined for 521 samples. Reference values were estimated in 291 blood donors. Additionally, the influence of sample turbidity, a major problem of the present Synchron LX20 CRP method, was evaluated. Results: Measurement of CPR by the BN ProSpec was linear down to 0·2 mg/L, whereas the linearity of Synchron LX20 PRO showed some systematic discrepancies. Over the whole measured range (0·2-250 mg/L), precision (coefficient of variation, CV) was ≤3·7% for the BN ProSpec and ≤6·1% for the LX20 PRO. The Synchron LX20 PRO hs-CRP method was found to be superior to the current routine Synchron LX20 CRP method with regard to precision in the low concentration range and the influence of sample turbidity. Both in the low concentration range and especially in the high concentration range, large discrepancies between methods were observed. Conclusion: Although acceptable performance was found for the Synchron LX20 PRO hs-CRP method, overall the performance of the BN ProSpec hs-CRP method was superior. However, standardization among assays needs further improvement in both the low and the high concentration ranges.
Reference ranges for muscle carnitine concentration in children
Authors: Angsten Gertrud , Cederblad Gitten , Meurling Staffan 
Published: July 2003

Background: We investigated muscle and plasma carnitine concentrations in children to establish reference intervals for use following biopsy of skeletal muscle. Methods: The study comprised 50 children from newborns up to 14 years of age, all undergoing elective surgery. They were divided into six age groups, the youngest 0-2 days and the oldest 11-14 years. The samples were taken at the beginning of surgery. Results: Gestational age was a major determinant of the total muscle carnitine concentration in newborns (Spearman's rs = 0·692, P < 0·01). This concentration was low during the first year, but subsequently did not differ between age groups. In neonates the median value (range) for total carnitine concentration in skeletal muscle was 5·9 (2·2-15·9) µmol/g dry weight and the free to total carnitine ratio was 62 (31-81)%. In children 1-12 months old the corresponding figures were 6·0 (3·5-7·9) µmol/g dry weight and 51 (28-71)% and in those 1-14 years they were 12·1 (6·6-17·4) µmol/g dry weight and 76 (42-92)%. Conclusion: This study shows that muscle carnitine concentrations in newborns are dependent on gestational age. The data suggest that there is an accretion of carnitine in skeletal muscle during the first year of life. Reference intervals are given.
A comparative study of tissue transglutaminase antibodies and endomysium antibody immunofluorescence in routine clinical laboratory practice
Authors: Sinclair David , Pearce Callum B , Saas Michael S. L. , Poller David 
Published: July 2003

Background: The demand for screening for coeliac disease has grown rapidly over the last few years. Laboratories depending on immunofluorescence assays are faced with an increasing workload using a labour-intensive test, and an alternative to this test has been sought. This study compares tissue transglutaminase (TTG) and endomysium antibodies (EMA) in a routine clinical laboratory situation. Methods: An immunofluorescence IgA EMA test was compared with a guinea pig TTG antibody ELISA for 816 unselected requests for gut antibody screening. Discrepant results were investigated more fully using a variety of human source TTG antigen kits. Results: Guinea pig TTG ELISA and EMA assays showed agreement for 93·6% of samples. Four samples were misclassified and 48 samples gave false positive TTG results. Study of 46 EMA samples (this group included 39 of the 'discrepant' negative EMA/positive guinea pig TTG group) using three different human purified and/or recombinant TTG sources showed that 42 patients had no TTG antibodies using human sources, three were misclassified and one patient had negative EMA and positive TTG results that could not be readily explained. Further study of 32 EMA positive samples showed almost complete agreement between the human source TTG kits. Conclusions: We can recommend the replacement of EMA with ELISA for TTG antibodies for the routine screening for coeliac disease, but all positive TTG antibodies should still be followed up with IgA EMA and samples should be screened for IgA deficiency.
Measurement of urinary porphyrins and porphyrin precursors in Dutch hospital laboratories: a review of quality control over 5 years
Authors: Zuijderhoudt Floris M. J. , Weykamp Cas W. , Willems Hans L. 
Published: July 2003

Background: We evaluated a quality control scheme for the measurement of urinary uroporphyrin, coproporphyrin, total urinary porphyrins and precursors of urinary porphyrins, δ-aminolevulinic acid and porphobilinogen that was performed in The Netherlands during a period of 5 years. Methods: Six quality control samples were distributed each year to the participating laboratories. Mean concentrations and the corresponding coefficients of variation were calculated. Results: Coefficients of variation varied widely and were very high in the concentration ranges that can be found in patients with low-grade porphyria. Conclusion: Commutable calibrators are needed to improve the laboratory diagnosis of porphyria.
Rapid genetic testing for Gaucher disease by reverse hybridization
Authors: Halsall David J. , Kriegshäuser Gernot , Moritz Anne , Elsey Terence S. , Oberkanins Christian 
Published: July 2003

Background: We evaluated a reverse hybridization method for the simultaneous detection of nine mutations that are associated with Gaucher disease. Results and conclusion: Results were in agreement with those obtained by a polymerase chain reaction-restriction digestion method. The hybridization method produced results more quickly and with less operator input.
Measurement Properties of the Oxford Shoulder Score and Minimal Clinically Important Changes After Primary Total Shoulder Replacement Surgery
Authors: Fang Yi Ying , Ackerman Ilana N. , Page Richard , Harris Ian A. , Cashman Kara , Lorimer Michelle , Heath Emma , Soh Sze‐Ee 
Published: January 2024

ObjectiveWe evaluated the measurement properties of the Oxford Shoulder Score (OSS) and estimated the minimal clinically important change (MCIC) in patients undergoing primary total shoulder replacement in Australia.MethodsDeidentified data from the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. Pre‐ and 6‐month postoperative OSS scores were used, with the 5‐level EuroQoL quality of life instrument and shoulder pain scores used as comparators. Floor and ceiling effects, internal consistency reliability, construct validity, and responsiveness to change were evaluated using standard psychometric methods. Mean change and predictive modeling approaches (with and without adjustment for the proportion of improved patients) were used to calculate MCIC thresholds, with patient‐perceived improvement after surgery as the anchor.ResultsPreoperative OSS data were available for 1,117 patients (59% female; 90% aged ≥60 years) undergoing primary total shoulder replacement. No floor or ceiling effects were observed pre‐ or postoperatively. The OSS showed high internal consistency reliability (Cronbach alpha >0.89), good construct validity, and high responsiveness to change (effect size 1.88). The MCIC derived from the mean change method was 6.50 points (95% confidence interval [95% CI] 4.41–8.61). The predictive modeling approach produced an MCIC estimate of 8.42 points (95% CI 5.68–12.23) after adjustment.ConclusionThe OSS has good measurement properties to capture pain and function outcomes after shoulder replacement procedures and is highly responsive to change. Based on robust methods, an increase in OSS scores of at least eight points can be considered as meaningful improvement after surgery from the patient's perspective.
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