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Reference Values (reference + value)
Kinds of Reference Values Selected AbstractsReference Values Describing the Normal Mitral Valve and the Position of the Papillary MusclesECHOCARDIOGRAPHY, Issue 7 2007Petrus 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] Ultrasonographic Reference Values for Assessing the Normal Median Nerve in AdultsJOURNAL OF NEUROIMAGING, Issue 1 2009Michael S. Cartwright MD ABSTRACT BACKGROUND AND PURPOSE Several studies have evaluated the cross-sectional area of the median nerve at the wrist, but none have examined other sites along the median nerve. Nerve enlargement has been demonstrated in entrapment, hereditary and acquired neuropathies, as well as with intraneural masses, and cross-sectional area reference values at sites along the nerve will help in the evaluation of these conditions. In addition, muscle intrusion into the carpal tunnel has been implicated in carpal tunnel syndrome, but the normal amount of muscle intrusion has not been quantified. METHODS Fifty asymptomatic volunteers (100 arms) were evaluated to determine the mean cross-sectional area of the median nerve at 6 sites and the mean amount of muscle intruding into the carpal tunnel. RESULTS The cross-sectional area of the nerve was consistent along its course (7.5 to 9.8 mm2). The amount of muscle within the carpal tunnel varied greatly, with the mean area of flexor digitorum being 15.5 mm2 and lumbricals 13.5 mm2. CONCLUSIONS These reference values are necessary for advancing the field of neuromuscular ultrasound, because they facilitate studies of the median nerve in conditions such as entrapment, hereditary neuropathy, acquired neuropathy, and intraneural masses. [source] Determination of dichloroanilines in human urine by gas chromatography/mass spectrometry: validation protocol and establishment of Reference Values in a population group living in central ItalyRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2006Roberta Turci 3,4- and 3,5-Dichloroanilines (DCAs) are common markers of some non-persistent pesticides, e.g. linuron, diuron, vinclozolin, and iprodione. The general population may be exposed to these DCAs and/or their precursors mainly through diet. Since adverse effects on human health, such as endocrine disruption, have been reported, biological monitoring is essential for exposure assessment both of occupationally exposed subjects and of the general population. A highly sensitive and selective gas chromatography/mass spectrometry (GC/MS) method has been developed for the determination of 3,4- and 3,5-DCAs in urine using 4-chloro-2-methylaniline as an internal standard. The selected ion monitoring (SIM) mode was employed for quantitation of the analytes. The sample treatment procedure is simple and fast and no derivatization is required. The overall method was validated including uncertainty measurement. The limit of detection (LOD) and the lower limit of quantitation (LLOQ) were determined to be 0.005 and 0.010,µg/L for both analytes. The method was then applied to the establishment of reference values for a population group living in a rural area of central Italy (Novafeltria, Marche). A total of 151 out of 153 samples were found to be positive for 3,5-DCA, and 81.7% were positive for 3,4-DCA. For this group, 3,4-DCA levels ranged from 0.01 to 6.19,µg/L, while 3,5-DCA urinary concentrations were between 0.02 and 6.71,µg/L. Copyright © 2006 John Wiley & Sons, Ltd. [source] Reference values for anaerobic performance and agility in ambulatory children and adolescents with cerebral palsyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2010OLAF VERSCHUREN Aim, The aim of this study was to provide reference values of anaerobic performance and agility in a group of children and adolescents with spastic cerebral palsy (CP). Method, A total of 300 children (184 males, 116 females) with spastic CP were recruited from 26 rehabilitation centres in six different countries. Of these, 215 were classified at GMFCS level I (mean age 11y 2mo, SD 3y, range 6,18y) and 85 were classified at GMFCS level II (mean age 11y; SD 3y 1mo, range 6,18y). The children performed the Muscle Power Sprint Test (MPST) and the 10×5m sprint test in a standardized manner. To establish reference values, reference curves were created using generalized additive models for location, scale, and shape. Results, Height-related reference curves were created based on performance on the two tests. Interpretation, This study provides height-related reference values for anaerobic performance and agility for children and adolescents with CP classified at GMFCS levels I and II. These curves are clinically relevant and provide a user-friendly method in the interpretation of anaerobic performance and agility for children with spastic CP. [source] Alveolar and bronchial nitric oxide output in healthy childrenPEDIATRIC PULMONOLOGY, Issue 12 2008Anna Sepponen MD Abstract Exhaled nitric oxide (NO) concentration is a marker of pulmonary inflammation. It is usually measured at a single exhalation flow rate. However, measuring exhaled NO at multiple flow rates allows assessment of the flow-independent NO parameters: alveolar NO concentration, bronchial NO flux, bronchial wall NO concentration, and bronchial diffusing capacity of NO. Our aim was to determine the flow-independent NO parameters in healthy schoolchildren and to compare two different mathematical approaches. Exhaled NO was measured at four flow rates (10, 50, 100, and 200 ml/sec) in 253 schoolchildren (7,13 years old). Flow-independent NO parameters were calculated with linear method (flows ,50 ml/sec) and non-linear method (all flows). Sixty-six children (32 boys and 34 girls) with normal spirometry and no history or present symptoms of asthma, allergy, atopy or other diseases were included in the analysis. Median bronchial NO flux was 0.4 nl/sec (mean,±,SD: 0.5,±,0.3 nl/sec) and median alveolar NO concentration was 1.9 ppb (2.0,±,0.8 ppb) with the linear method. Bronchial NO flux correlated positively with height (r,=,0.423; P,<,0.001), FEV1 (r,=,0.358; P,=,0.003), and FVC (r,=,0.359; P,=,0.003). With the non-linear method, median bronchial wall NO concentration was 49.6 ppb (68.0,±,53.3 ppb) and bronchial diffusing capacity of NO was 10.0 pl/sec/ppb (11.8,±,7.5 pl/sec/ppb). The non-linear method gave lower alveolar NO concentration (1.4 [1.5,±,0.7] ppb, P,<,0.001) and higher bronchial NO flux (0.5 [0.6,±,0.3] nl/sec, P,<,0.001) than the linear method, but the results were highly correlated between the two methods (r,=,0.854 and r,=,0.971, P,<,0.001). In conclusion, the multiple flow rate method is feasible in children but different mathematical methods give slightly different results. Reference values in healthy children are of value when applying bronchial and alveolar NO parameters in the diagnostics and follow-up of inflammatory lung diseases. Pediatr. Pulmonol. 2008; 43:1242,1248. © 2008 Wiley-Liss, Inc. [source] Quantitative FRET Analysis With the E0GFP-mCherry Fluorescent Protein PairPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2009Lorenzo Albertazzi Fluorescence resonance energy transfer (FRET) between fluorescent proteins (FPs) is a powerful tool to investigate protein,protein interaction and even protein modifications in living cells. Here, we analyze the E0GFP-mCherry pair and show that it can yield a reproducible quantitative determination of the energy transfer efficiency both in vivo and in vitro. The photophysics of the two proteins is reported and shows good spectral overlap (Förster radius R0 = 51 Å), low crosstalk between acceptor and donor channels, and independence of the emission spectra from pH and halide ion concentration. Acceptor photobleaching (APB) and one- and two-photon fluorescence lifetime imaging microscopy (FLIM) are used to quantitatively determine FRET efficiency values. A FRET standard is introduced based on a tandem construct comprising donor and acceptor together with a 20 amino acid long cleavable peptidic linker. Reference values are obtained via enzymatic cleavage of the linker and are used as benchmarks for APB and FLIM data. E0GFP-mCherry shows ideal properties for FLIM detection of FRET and yields high accuracy both in vitro and in vivo. Furthermore, the recently introduced phasor approach to FLIM is shown to yield straightforward and accurate two-photon FRET efficiency data even in suboptimal experimental conditions. The consistence of these results with the reference method (both in vitro and in vivo) reveals that this new pair can be used for very effective quantitative FRET imaging. [source] Reference values of fetal orbital measurements by transvaginal scan in early pregnancyPRENATAL DIAGNOSIS, Issue 10 2002Paolo Rosati Abstract Objective To construct reference ranges of orbital diameters, measured in early pregnancy by transvaginal sonography. Methods The study group consisted of 2717 fetuses of pregnant women referred to our center and examined by transvaginal ultrasound between 11,16 week's gestation. Nomograms with confidence intervals (5th and 95th percentile) for each orbital measurement (orbital diameter, interocular and binocular distance) versus gestational age were produced. Results The orbital measurements increased in a linear fashion throughout early pregnancy with a good correlation with gestational age. Conclusion Transvaginal sonography is able to visualize and measure orbital diameters with accuracy in early pregnancy; reference ranges were developed that can be used to evaluate normal orbital development and can be helpful in the detection of syndromes with orbital growth defects and other associated fetal anomalies. Copyright © 2002 John Wiley & Sons, Ltd. [source] Ultrasonographic Morphometric Measurements of Digital Flexor Tendons and Ligaments of the Palmar Metacarpal Region in Haflinger HorsesANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2010S. Boehart With 2 figures and 3 tables Summary The aim of the study was to determine morphometric values of the superficial and deep digital flexor tendon, the inferior check ligament and the suspensory ligament in the palmar metacarpal region of sound Haflinger horses using ultrasonography and to assess the influence of different factors on them. The findings were compared with the literature. A total of 30 sound Haflinger mares aged 4,20 years were used. Transverse ultrasound images were obtained with an 8,10 linear MHz transducer and the cross-sectional area, the circumference and the dorsopalmar and lateromedial width were determined for each structure at six regions of interest (ROI) in both forelimbs. The coefficient of variation was <3%. The structures were compared between each other and the values of each structure at the ROIs. Age, height at the withers, body mass index, diameter of the Os metacarpale III and the circumference of the mid-metacarpal region showed significant influences on some of the parameters. Reference values for the tendons and ligaments in the palmar metacarpal region in sound Haflinger mares were obtained and the influence of different factors was tested. Description of the dimensional relationship between the structures and comparison of the data with the literature provide knowledge required for adequate veterinary care. [source] Author response to: Reference values for clinical chemistry tests during normal pregnancyBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 12 2008A Larsson No abstract is available for this article. [source] Reference values for clinical chemistry tests during normal pregnancyBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 7 2008A Larsson Objective, Reference values are usually defined based on blood samples from healthy men or nonpregnant women. This is not optimal as many biological markers changes during pregnancy and adequate reference values are of importance for correct clinical decisions. There are only few studies on the variations of laboratory tests during normal pregnancies, especially during the first two trimesters. It is thus a need to establish such reference values. Design, Longitudinal study of laboratory markers in normal pregnancies. Setting, Uppsala University Hospital, Sweden. Population, Healthy pregnant females. Methods, We have studied 25 frequently used laboratory tests during 52 normal pregnancies. Each woman was sampled up to nine times and the samples were divided according to collection time into the following groups: gestational week 7,17; week 17,24; week 24, 28; week 28,31; week 31,34; week 34,38; predelivery (0,2 weeks before delivery) and postpartum (>6 weeks after delivery). The 2.5 and 97.5 percentiles for these markers were calculated according to the recommendations of the International Federation of Clinical Chemistry on the statistical treatment of reference values. Results, Reference intervals are reported for plasma alanine aminotransferase, albumin, alkaline phosphatase, pancreas amylase, apolipoprotein A1, apolipoprotein B, aspartate aminotransferase, bilirubin, calcium, chloride, creatinine, cystatin C, ferritin, ,-glutamyltransferase, iron, lactate dehydrogenase, magnesium, phosphate, potassium, sodium, transferrin, triglycerides, thyroid-stimulating hormone, urate and urea during these pregnancy periods. Conclusions, Most of the analytes change during normal pregnancy. It is thus of importance to use special reference values during pregnancy. [source] Transthyretin levels in the vitreous correlate with change in visual acuity after vitrectomyACTA OPHTHALMOLOGICA, Issue 2009E VAN AKEN Purpose Little is known about biochemical markers related to change in visual acuity after vitrectomy. We investigated the potential use of transthyretin (TTR), a carrier of the retinol/retinol-binding protein, as a biochemical marker protein. Methods We measured TTR using immunonephelometry in a group of patients (n=77) in longstanding (> 1 week) retinal detachment (n=29), fresh (< 1 week) retinal detachment (n=17), macular holes (n=20), or diabetic retinopathy (n=11). Vitreous samples were taken at the start of every vitrectomy procedure. For reference values, cadaver specimens (n=73) were used. Results Reference values for vitreous TTR (median 18 mg/l; IQR 4-24 mg/l) comprised 2.2% of reference values for vitreous protein levels (median 538 mg/l; IQR 269-987 mg/l). Vitreous TTR values of patients were comparable in all disorders. Vitreous TTR values were higher in phakic (median 22.5 mg/l; IQR 10-27 mg/l) than in pseudophakic patients (median 12 mg/l; IQR 8-19 mg/l)(p=0.06). Postoperative change in visual acuity correlated well with vitreous TTR values found peroperatively (rs=0.408; p=0.012). Both change in visual acuity and lens status were the only variables which proved to explain the variance of TTR (multiple correlation coefficient: 0.494; phakic status: t=2.767; p=0.0084; and change in visual acuity t=2.924: p=0.0056). Conclusion Vitreous fluid concentrations of TTR can be regarded as a biochemical marker for retinal function. [source] Reference values for change in body mass index from birth to 18 years of ageACTA PAEDIATRICA, Issue 6 2003J Karlberg Body mass index (BMI) has become the measure of choice for determination of nutritional status during the paediatric years, as in adults. Recently, several cross-sectional BMI childhood reference values standards have been published. In order precisely to evaluate childhood nutritional interventions, reference values allowing for the evaluation of changes in BMI values are also needed. For the first time, such reference values can be presented based on 3650 longitudinally followed healthy Swedish children born full term. The reference values for the change in BMI are given as the change in BMI standard deviation scores. The reference values are given as means of mathematical functions adjusting for gender, age of the child and the length of the interval between two measurements for interval lengths of 0.25 to 1.0 y before 2y of age and of 1 to 5 y between birth and 18 y. The usefulness of the reference values is proved by a graph that forms a part of a clinical computer program; the -2 to +2 standard deviation range of the predicted change in BMI can be computed for an individual child and drawn in the graph as an extended support for clinical decision-making. Conclusion: For the first time this communication gives access to BMI growth rate values that can be used both in research and in the clinic to evaluate various interventions, be they nutritional, surgical or therapeutic. [source] CE-ESI-MS/MS as a rapid screening tool for the comparison of protein,ligand interactionsELECTROPHORESIS, Issue 7 2010Thomas Hoffmann Abstract In drug development, the combinatorial synthesis of drug libraries is common use, therefore efficient tools for the characterization of drug candidates and the extent of interaction between a drug and its target protein is a central question of analytical interest. While biological activity is tested today by enzyme assays, MS techniques attract more and more attention as an alternative for a rapid comparison of drug,target interactions. CE enables the separation of proteins and drug,enzyme complexes preserving their physiological activity in aqueous media. By hyphenating CE with ESI-MS/MS, the binding strength of enzyme inhibitors can be deduced from MS/MS experiments, which selectively release the inhibitor from the drug,target complex after CID. In this study, ,-chymotrypsin (CT), a serine protease, was chosen as a model compound. Chymostatin is a naturally occurring peptide aldehyde binding to CT through a hemiacetal bond and electrostatic interaction. First, a CE separation was developed, which allows the analysis of ,-CT and a chymotrypsin,chymostatin complex under MS-compatible conditions. The use of neutral-coated CE capillaries was mandatory to reduce analyte,wall interactions. ESI-quadrupole ion trap-MS was worked out to demonstrate the selective drug release after CID. Fragmentation of the drug,enzyme complex was monitored in dependence from the excitation energy in the ion trap, leading to the V50 voltage that enables 50% complex fragmentation as a reference value for chymotrypsin,chymostatin complex. A stable CE-ESI-MS/MS setup was established, which preserves the drug,enzyme complexes during ionization,desolvation processes. With this optimized setup, different CT inhibitors could be investigated and compared. [source] The Evaluation of Thyroid Functions, Thyroid Antibodies, and Thyroid Volumes in Children with Epilepsy during Short-Term Administration of Oxcarbazepine and ValproateEPILEPSIA, Issue 11 2006Ali Cansu Summary:,Purpose: The aim of this study was to evaluate the effects of short-term oxcarbazepine (OXC) and valproate (VPA) monotherapy on thyroid functions in children. Methods: Fifty-five newly diagnosed epileptic children with normal thyroid functions (confirmed with the thyrotropin releasing hormone stimulation test) participated in this study. VPA treatment was started in 30 patients and OXC in 25 patients. Serum thyroxine (T4), free thyroxine (fT4), triiodothyronine (T3), free triiodothyronine (fT3), reverse T3 (rT3), thyroid peroxidase antibodies (TPO-ab), and urine iodine levels were evaluated at baseline and at the third and sixth months of therapy. Results: In the OXC group, serum T4, fT4, T3, fT3, and rT3 levels were found to be decreased at the third and sixth months, the differences were significant compared to the baseline values except for fT3 levels at the third month and fT4 and rT3 levels at the sixth month (p < 0.05). At the sixth month, serum T4 level dropped below the normal reference value in 8 (32%), fT4 in 5 (20%), T3 in 4 (16%), and fT3 in 3 (12%) patients. In the VPA group, mean T4, fT4, T3, fT3, and rT3 levels at 3 and 6 months remained similar compared to the baseline values (p > 0.05). Mean serum thyroid stimulating hormone levels increased significantly at the sixth month compared to the baseline values in the VPA group (p < 0.05) while it remained unchanged in the OXC group (p > 0.05). There was no effect of either drug on urinary iodine excretion and serum TPO-ab levels remained in normal ranges throughout the study. Conclusions: In this prospective study, it is documented that children under short-term OXC or VPA therapy showed altered thyroid functions similar to the changes observed after long-term treatment. Although, the clinical significance of these results need to be evaluated with future studies, this observation of altered thyroid functions points out that thyroid functions may need to be monitored closely in children receiving antiepileptic treatment, even in the short-time interval. [source] Sampling variability of liver fibrosis in chronic hepatitis CHEPATOLOGY, Issue 6 2003Pierre Bedossa M.D. Fibrosis is a common endpoint of clinical trials in chronic hepatitis C, and liver biopsy remains the gold standard for fibrosis evaluation. However, variability in the distribution of fibrosis within the liver is a potential limitation. Our aim was to assess the heterogeneity of liver fibrosis and its influence on the accuracy of assessment of fibrosis with liver biopsy. Surgical samples of livers from patients with chronic hepatitis C were studied. Measurement of fibrosis was performed on the whole section by using both image analysis and METAVIR score (reference value). From the digitized image of the whole section, virtual biopsy specimens of increasing length were produced. Fibrosis was assessed independently on each individual virtual biopsy specimen. Results were compared with the reference value according to the length of the biopsy specimen. By using image analysis, the coefficient of variation of fibrosis measurement with 15-mm long biopsy specimens was 55%; and for biopsy specimens of 25-mm length it was 45%. By using the METAVIR scoring system, 65% of biopsies 15 mm in length were categorized correctly according to the reference value. This increased to 75% for a 25-mm liver biopsy specimen without any substantial benefit for longer biopsy specimens. Sampling variability of fibrosis is a significant limitation in the assessment of fibrosis with liver biopsy. In conclusion, this study suggests that a length of at least 25 mm is necessary to evaluate fibrosis accurately with a semiquantitative score. Sampling variability becomes a major limitation when using more accurate methods such as automated image analysis. [source] Relationship between canopy height and the reference value of surface conductance for closed coniferous standsHYDROLOGICAL PROCESSES, Issue 12 2003Hikaru Komatsu Abstract When estimating the dry-canopy evaporation rate of coniferous stands using the Penman,Monteith equation, it is crucial to determine the reference value of surface conductance Gs. This paper examines the relationship between canopy height and the reference value of Gs based on the maximum value of Gs with a vapour pressure deficit , 1·0 kPa, ,s max. There is a clear correlation between canopy height and ,s max when the projected leaf area index ,3·0. This suggests that using this relationship will enable more accurate determination of the reference value of Gs for closed stands. Copyright © 2003 John Wiley & Sons, Ltd. [source] Discrete-time low-gain control of linear systems with input/output nonlinearitiesINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2001T. Fliegner Abstract Discrete-time low-gain control strategies are presented for tracking of constant reference signals for finite-dimensional, discrete-time, power-stable, single-input, single-output, linear systems subject to a globally Lipschitz, non-decreasing input nonlinearity and a locally Lipschitz, non-decreasing, affinely sector-bounded output nonlinearity (the conditions on the output nonlinearities may be relaxed if the input nonlinearity is bounded). Both non-adaptive and adaptive gain sequences are considered. In particular, it is shown that applying error feedback using a discrete-time ,integral' controller ensures asymptotic tracking of constant reference signals, provided that (a) the steady-state gain of the linear part of the plant is positive, (b) the positive gain sequence is ultimately sufficiently small and (c) the reference value is feasible in a very natural sense. The classes of input and output nonlinearities under consideration contain standard nonlinearities important in control engineering such as saturation and deadzone. The discrete-time results are applied in the development of sampled-data low-gain control strategies for finite-dimensional, continuous- time, exponentially stable, linear systems with input and output nonlinearities. Copyright © 2001 John Wiley & Sons, Ltd. [source] Skeletal Fluorosis From Instant Tea,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2008Michael P Whyte MD Abstract Introduction: Skeletal fluorosis (SF) can result from prolonged consumption of well water with >4 ppm fluoride ion (F,; i.e., >4 mg/liter). Black and green teas can contain significant amounts of F,. In 2005, SF caused by drinking 1,2 gallons of double-strength instant tea daily throughout adult life was reported in a 52-yr-old woman. Materials and Methods: A 49-yr-old woman developed widespread musculoskeletal pains, considered fibromyalgia, in her mid-30s. Additionally, she had unexplained, increasing, axial osteosclerosis. She reported drinking 2 gallons of instant tea each day since 12 yr of age. Fluoxetine had been taken intermittently for 5 yr. Ion-selective electrode methodology quantitated F, in her blood, urine, fingernail and toenail clippings, tap water, and beverage. Results: Radiographs showed marked uniform osteosclerosis involving the axial skeleton without calcification of the paraspinal, intraspinal, sacrotuberous, or iliolumbar ligaments. Minimal bone excrescences affected ligamentous attachments in her forearms and tibias. DXA Z-scores were +10.3 in the lumbar spine and +2.8 in the total hip. Her serum F, level was 120 ,g/liter (reference range, 20,80 ,g/liter), and a 24-h urine collection contained 18 mg F,/g creatinine (reference value, <3). Fingernail and toenail clippings showed 3.50 and 5.58 mg F,/kg (control means, 1.61 and 2.02, respectively; ps < 0.001). The instant tea beverage, prepared as usual extra strength using tap water with ,1.2 ppm F,, contained 5.8 ppm F,. Therefore, the tea powder contributed ,35 mg of the 44 mg daily F, exposure from her beverage. Fluoxetine provided at most 3.3 mg of F, daily. Conclusions: SF from habitual consumption of large volumes of extra strength instant tea calls for recognition and better understanding of a skeletal safety limit for this modern preparation of the world's most popular beverage. [source] Recovery From Skeletal Fluorosis (an Enigmatic, American Case),,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2007Etah S Kurland Abstract A 52-year-old man presented with severe neck immobility and radiographic osteosclerosis. Elevated fluoride levels in serum, urine, and iliac crest bone revealed skeletal fluorosis. Nearly a decade of detailed follow-up documented considerable correction of the disorder after removal of the putative source of fluoride (toothpaste). Introduction: Skeletal fluorosis, a crippling bone disorder, is rare in the United States, but affects millions worldwide. There are no data regarding its reversibility. Materials and Methods: A white man presented in 1996 with neck immobility and worsening joint pains of 7-year duration. Radiographs revealed axial osteosclerosis. Bone markers were distinctly elevated. DXA of lumbar spine (LS), femoral neck (FN), and distal one-third radius showed Z scores of +14.3, +6.6, and ,0.6, respectively. Transiliac crest biopsy revealed cancellous volume 4.5 times the reference mean, cortical width 3.2 times the reference mean, osteoid thickness 25 times the reference mean, and wide and diffuse tetracycline uptake documenting osteomalacia. Fluoride (F) was elevated in serum (0.34 and 0.29 mg/liter [reference range: <0.20]), urine (26 mg/liter [reference range: 0.2,1.1 mg/liter]), and iliac crest (1.8% [reference range: <0.1%]). Tap and bottled water were negative for F. Surreptitious ingestion of toothpaste was the most plausible F source. Results: Monitoring for a decade showed that within 3 months of removal of F toothpaste, urine F dropped from 26 to 16 mg/liter (reference range: 0.2,1.1 mg/liter), to 3.9 at 14 months, and was normal (1.2 mg/liter) after 9 years. Serum F normalized within 8 months. Markers corrected by 14 months. Serum creatinine increased gradually from 1.0 (1997) to 1.3 mg/dl (2006; reference range: 0.5,1.4 mg/dl). Radiographs, after 9 years, showed decreased sclerosis of trabeculae and some decrease of sacrospinous ligament ossification. DXA, after 9 years, revealed 23.6% and 15.1% reduction in LS and FN BMD with Z scores of +9.3 and +4.8, respectively. Iliac crest, after 8.5 years, had normal osteoid surface and thickness with distinct double labels. Bone F, after 8.5 years, was 1.15% (reference range, <0.1), which was a 36% reduction (still 10 times the reference value). All arthralgias resolved within 2 years, and he never fractured, but new-onset nephrolithiasis occurred within 9 months and became a chronic problem. Conclusions: With removal of F exposure, skeletal fluorosis is reversible, but likely impacts for decades. Patients should be monitored for impending nephrolithiasis. [source] Re-evaluation of cord blood arterial and venous reference ranges for pH, pO2, pCO2, according to spontaneous or cesarean deliveryJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2010K. Kotaska Abstract Umbilical cord blood gas analysis (pO2 and pCO2) is now recommended in all high-risk baby deliveries and in some centers it is performed routinely following all deliveries. The aim of this study was to re-evaluate cord blood arterial and venous reference ranges for pH, pO2, pCO2 in newborns, delivered by spontaneous vaginal delivery (SVD) and by cesarean section (CS) performed in Faculty Hospital Motol. Two groups of subjects were selected for the study. Group I consisted of 303 newborns with SVD. Group II consisted of 189 newborns delivered by cesarean section. Cord blood samples were analyzed for standard blood gas and pH, using the analytical device Rapid Lab 845 and Rapid Lab 865. We obtained reference values expressed as range (lower and upper reference value expressed as 2.5 and 97.5 percentiles) for cord blood in newborns with SVD: arterial cord blood: pH=7.01,7.39; pCO2=4.12,11.45,kPa; pO2=1.49,5.06,kPa; venous cord blood: pH=7.06,7.44; pCO2=3.33,9.85,kPa; pO2=1.80,6.29,kPa. We also obtained reference values for cord blood in newborns delivered by CS: arterial cord blood: pH=7.05,7.39; pCO2=5.01,10.60,kPa; pO2=1.17,5.94,kPa; venous cord blood: pH=7.10,7.42; pCO2=3.88,9.36,kPa; pO2=1.98,7.23,kPa. Re-evaluated reference ranges play essential role in monitoring conditions of newborns with spontaneous and caesarean delivery. J. Clin. Lab. Anal. 24:300,304, 2010. © 2010 Wiley-Liss, Inc. [source] Quantitative contrast-enhanced perfusion measurements of the human lung using the prebolus approachJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2009Markus Oechsner MS Abstract Purpose To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to the global lung perfusion (GLP). Materials and Methods Eleven volunteers were examined by applying different contrast agent doses (0.5, 1.0, 2.0, and 3.0 mL gadolinium diethylene triamine pentaacetic acid [Gd-DTPA]), using a saturation-recovery (SR) true fast imaging with steady precession (TrueFISP) sequence. PBF and PBV were determined for single bolus and prebolus. Region of interest (ROI) evaluation was performed and parameter maps were calculated. Additionally, cardiac output (CO) and lung volume were determined and GLP was calculated as a contrast agent,independent reference value. Results The prebolus results showed good agreement with low-dose single-bolus and GLP: PBF (mean ± SD in units of mL/minute/100 mL) = single bolus 190 ± 73 (0.5-mL dose) and 193 ± 63 (1.0-mL dose); prebolus 192 ± 70 (1.0,2.0-mL dose) and 165 ± 52 (1.0,3.0-mL dose); GLP (mL/minute/100 mL) = 187 ± 34. Higher single-bolus resulted in overestimated values due to arterial input function (AIF) saturation. Conclusion The prebolus approach enables independent determination of appropriate doses for AIF and tissue signal. Using this technique, the signal-to-noise ratio (SNR) from lung parenchyma can be increased, resulting in improved PBF and PBV quantification, which is especially useful for the generation of parameter maps. J. Magn. Reson. Imaging 2009;30:104,111. © 2009 Wiley-Liss, Inc. [source] Cardiac amyloidosis: MR imaging findings and T1 quantification, comparison with control subjectsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2007Gabriele A. Krombach MD Abstract In cardiac amyloidosis an interstitial deposition of amyloid fibrils causes concentric thickening of the atrial and ventricular walls. We describe the results of tissue characterization of the myocardium by T1 quantification and MRI findings in a patient with cardiac amyloidosis. The T1 time of the myocardium was elevated compared to that in individuals without amyloidosis. The T1 time of the myocardium was 1387 ± 63 msec (mean value obtained from four measurements ± standard deviation [SD]) in the patient with cardiac amyloidosis, while the reference value obtained from the myocardium of 10 individuals without known myocardial disease was 1083 ± 33 msec (mean value ± SD). In combination with other MR findings suggestive of amyloidosis, such as homogeneous thickening of the ventricular and atrial walls, thickening of the valve leaflets, restrictive filling pattern, and reduction of systolic function, T1 quantification may increase diagnostic confidence. J. Magn. Reson. Imaging 2007;25:1283,1287. © 2007 Wiley-Liss, Inc. [source] Plasma Homocysteine, Fasting Insulin, and Androgen Patterns among Women with Polycystic Ovaries and InfertilityJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 3 2001Dr. E. Scott Sills Abstract Objective: To measure plasma homocysteine, androgen, and insulin concentrations in women with normal and polycystic-appearing ovaries in an infertility setting. Methods: Among women referred for infertility evaluation (n = 54), homocysteine, androstenedione, DHEAS, total testosterone, fasting insulin/glucose and methyltetrahydrofolate reductase (MTHFR) polymorphism status (C677T mutation) were studied. Ovaries were examined via transvaginal sonogram by one observer and scored as either normal (n = 18) or polycystic (n = 36). Results: When polycystic ovaries were identified, mean total testosterone was significantly higher than when non-polycystic ovaries were present (p = 0.01), although no measured androgen was outside the normal reference range in either group. Average BMI was higher in the polycystic group, but the difference was not significant (p = 0.10). We observed a trend toward higher mean fasting insulin levels in women with polycystic ovaries, but this increase did not reach statistical significance (p = 0.07). Median plasma homocysteine was identical (7.0 mmol/l) in both populations, and no study subject exceeded the current recommended maximum reference value. Conclusions: In this population, the presence of polycystic ovaries was associated with higher serum androgens (especially total testosterone) although none of the measured androgens were above the normal range. While fasting insulin levels were also higher in this group, median plasma homocysteine levels were similar irrespective of ovarian morphology. Concomitant plasma homocysteine derangements in this population of young, lean patients with polycystic-appearing ovaries seem unlikely. Further studies are needed to clarify the role(s) of homocysteine in human reproductive physiology. [source] Granulation sensing of first-break ground wheat using a near-infrared reflectance spectrometer: studies with soft red winter wheats,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2003Melchor C Pasikatan Abstract A near-infrared reflectance spectrometer, previously evaluated as a granulation sensor for first-break ground wheat from six wheat classes and hard red winter (HRW) wheats, was further evaluated for soft red winter (SRW) wheats. Two sets of 35 wheat samples, representing seven cultivars of SRW wheat ground by an experimental roller mill at five roll gap settings (0.38, 0.51, 0.63, 0.75 and 0.88,mm), were used for calibration and validation. Partial least squares regression was applied to develop the granulation models using combinations of four data pretreatments (log(1/R), baseline correction, unit area normalisation and derivatives) and subregions of the 400,1700,nm wavelength range. Cumulative mass of size fraction was used as reference value. Models that corrected for path length effects (those that used unit area normalisation) predicted the bigger size fractions well. The model based on unit area normalisation/first derivative predicted 34 out of 35 validation spectra with standard errors of prediction of 3.53, 1.83, 1.43 and 1.30 for the >1041, >375, >240 and >136,µm size fractions respectively. Because of less variation in mass of each size fraction, SRW wheat granulation models performed better than the previously reported models for six wheat classes. However, because of SRW wheat flour's tendency to stick to the underside of sieves, the finest size fraction of these models did not perform as well as the HRW wheat models. © 2003 Society of Chemical Industry [source] Hepatitis B virus DNA levels, precore mutations, genotypes and histological activity in chronic hepatitis BJOURNAL OF VIRAL HEPATITIS, Issue 4 2000Lindh The present study aimed to clarify how viraemia levels reflect the clinical stages of chronic hepatitis B virus (HBV) infection, in particular studying whether ,healthy carriers' can be identified by analysing HBV DNA levels with a highly sensitive quantitative assay. Histology activity index (HAI), alanine aminotransferase (ALT) level, genotype and precore mutations were compared with the HBV DNA level, as measured using the Amplicor HBV Monitor assay in a prospective study. In 124 hepatitis B e antigen-negative (HBeAg,) patients, the majority with mild liver disease, log HBV DNA levels showed a Gaussian distribution around a geometric mean of 33 000 genome copies ml,1, and increasing HBV DNA level was associated with significantly higher inflammation (HAIinfl) and fibrosis (HAIfibr) scores and higher ALTi (ALT ÷ the upper reference value). Severe inflammation (HAIinfl , 7) was seen in 83% (five of six), 36% (eight of 22) and 3% (one of 37) of HBeAg, patients with HBV DNA > 107, > 2 × 105 and < 104 copies ml,1, respectively. In severe HBeAg, hepatitis, patients with precore wild-type infection had lower HBV DNA levels than those with precore mutants. In 36 HBeAg-positive (HBeAg+) patients, no correlation between HBV DNA level and liver damage was seen. Ninety-six per cent of HBeAg, patients with ALTi < 0.5 had HAIinfl , 3. In HBeAg, carriers with ALTi 0.5,1.0, the relative risk for severe inflammation, comparing HBV DNA > 2 × 105 copies ml,1vs < 2 × 105 copies ml,1, was 14.7. In conclusion, in HBeAg, carriers, HBV DNA < 104 copies ml,1 or ALTi < 0.5 indicates mild inflammation, while > 2 × 105 copies ml,1 of HBV DNA may justify further investigations. Precore status may be relevant for the interpretation of viraemia. [source] Evaluation of a Navigation System for ENT with Surgical Efficiency Criteria,THE LARYNGOSCOPE, Issue 4 2006Gero Strau MD Abstract The aim of this study is the evaluation of a navigation system (NaviBase) for ENT surgery. For this purpose, a new methodology for the evaluation of surgical and ergonomic system properties has been developed. The practicability of the evaluation instruments will be examined using the example of the overall assessment of the system in comparison with the current surgical standard and with other systems using clinical efficiency criteria. The evaluation is based on 102 ENT surgical applications; of these, 89 were functional endoscopic sinus surgeries (FESS). The evaluation of surgical and ergonomic performance factors was performed by seven ENT surgeons. To evaluate surgical system properties, the Level of Quality (LOQ) in 89 cases of the FESS was determined. It compares the existing information of the surgeon with that of the navigation system on a scale of 0 to 100 and with a mean value of 50 and places it in a relationship to the clinical impact. The intraoperative change of the planned surgical strategy (Change of Surgical Strategy) was documented. The ergonomic factors of the system with the categories of Overall Confidence (Trust), awareness of the situation (Situation Awareness), influence on the operating team, requirements for specific skills (Skill Set Requirement), and cognitive load (Workload Shift) were recorded for all surgical procedures as Level of Reliance (LOR). In the evaluation of the surgical system properties, an average evaluation of the quality of the information, as an LOQ of 63.59, resulted. Every second application of the navigation system (47.9%), on average, led to a change in the surgical strategy. An extension/enhancement of the indication of the endonasal approach through the use of the navigation system was shown in 7 of 102 (6.8%) cases. The completion of the resection in the FESS was rated by 74% of group I and 11% of group II as better in comparison with the standard approach. Total confidence shows a positive evaluation of 3.35 in the LOR. To supplement the evaluation of the navigation system, the technical parameters were included. The maximum deviation, Amax, of the displayed position of the reference value amounted to 1.93 mm. The average deviation was at 1.29 mm with an SD above all values, sd, of 0.29. The subsequent economic evaluation resulted in an effective average extra expenditure of time of 1.35 minutes per case. The overall evaluation of the system imparts application-relevant information beyond the technical details and permits comparability between different assistance systems. [source] Coupling a mass-conserving semi-Lagrangian scheme (SLICE) to a semi-implicit discretization of the shallow-water equations: Minimizing the dependence on a reference atmosphereTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 646 2010J. Thuburn Abstract In a recent paper, a conservative semi-Lagrangian mass transport scheme SLICE has been coupled to a semi-implicit semi-Lagrangian scheme for the shallow-water equations. The algorithm involves the solution at each timestep of a nonlinear Helmholtz problem, which is achieved by iterative solution of a linear ,inner' Helmholtz problem; this framework, as well as the linear Helmholtz operator itself, are the same as would be used with a non-conservative interpolating semi-Lagrangian scheme for mass transport. However, in order to do this, a reference value of geopotential was introduced into the discretization. It is shown here that this results in a weak dependence of the results on that reference value. An alternative coupling is therefore proposed that preserves the same solution framework and linear Helmholtz operator but, at convergence of the nonlinear solver, has no dependence on the reference value. However, in order to maintain accuracy at large timesteps, this approach requires a modification to how SLICE performs its remapping. An advantage of removing the dependence on the reference value is that the scheme then gives consistent tracer transport. Copyright © 2010 Royal Meteorological Society and Crown Copyright. Published by John Wiley & Sons, Ltd. [source] Fully Autonomous Preload-Sensitive Control of Implantable Rotary Blood PumpsARTIFICIAL ORGANS, Issue 9 2010Andreas Arndt Abstract A pulsatility-based control algorithm with a self-adapting pulsatility reference value is proposed for an implantable rotary blood pump and is to be tested in computer simulations. The only input signal is the pressure difference across the pump, which is deduced from measurements of the pump's magnetic bearing. A pulsatility index (PI) is calculated as the mean absolute deviation from the mean pressure difference. As a second characteristic, the gradient of the PI with respect to the pump speed is derived. This pulsatility gradient (GPI) is used as the controlled variable to adjust the operating point of the pump when physiological variables such as the systemic arterial pressure, left ventricular contractility, or heart rate change. Depending on the selected mode of operation, the controller is either a linear controller or an extremum-seeking controller. A supervisory mechanism monitors the state of the system and projects the system into the region of convergence when necessary. The controller of the GPI continuously adjusts the reference value for PI. An underlying robust linear controller regulates the PI to the reference value in order to take into account changes in pulmonary venous return. As a means of reacting to sudden changes in the venous return, a suction detection mechanism was included. The control system is robustly stable within a wide range of physiological variables. All the clinician needs to do is to select between the two operating modes. No other adjustments are required. The algorithm showed promising results which encourage further testing in vitro and in vivo. [source] Physiological Control of a Rotary Blood Pump With Selectable Therapeutic Options: Control of Pulsatility GradientARTIFICIAL ORGANS, Issue 10 2008Andreas Arndt Abstract A control strategy for rotary blood pumps meeting different user-selectable control objectives is proposed: maximum support with the highest feasible flow rate versus medium support with maximum ventricular washout and controlled opening of the aortic valve (AoV). A pulsatility index (PI) is calculated from the pressure difference, which is deduced from the axial thrust measured by the magnetic bearing of the pump. The gradient of PI with respect to pump speed (GPI) is estimated via online system identification. The outer loop of a cascaded controller regulates GPI to a reference value satisfying the selected control objective. The inner loop controls the PI to a reference value set by the outer loop. Adverse pumping states such as suction and regurgitation can be detected on the basis of the GPI estimates and corrected by the controller. A lumped-parameter computer model of the assisted circulation was used to simulate variations of ventricular contractility, pulmonary venous pressure, and aortic pressure. The performance of the outer control loop was demonstrated by transitions between the two control modes. Fast reaction of the inner loop was tested by stepwise reduction of venous return. For maximum support, a low PI was maintained without inducing ventricular collapse. For maximum washout, the pump worked at a high PI in the transition region between the opening and the permanently closed AoV. The cascaded control of GPI and PI is able to meet different control objectives and is worth testing in vitro and in vivo. [source] Flow cytometric differential of leukocyte populations in normal bone marrow: Influence of peripheral blood contamination1,CYTOMETRY, Issue 1 2009R. A. Brooimans Abstract Background: Availability of immunophenotypic reference values for the various leukocyte populations distributed in bone marrow may be helpful to recognize abnormal bone marrow development and, therefore, useful as first screening of individuals with suspected hematological malignancies or other hematopoietic disorders. Methods: A single tube four-color staining panel (CD66abce/CD14/CD45/CD34) together with a predefined gating strategy was utilized to immunologically differentiate the distribution of the major leukocyte populations in bone marrow aspirates of healthy donors. The sample-blood erythrocyte ratio was applied to assess the amount of blood contamination of marrow and account for this in the marrow value estimates. Results: The frequency of the major leukocyte populations in bone marrow of 134 normal donors were for granulocytes: mean, 69.4%; SD, 10.3%; monocytes: mean, 4.7%; SD, 2.3%; lymphocytes: mean, 18.3%; SD, 8.7%. The frequency of the immature cell population that included precursor cells of each of the cell lineages among other cell types were mean 5.0%; SD 2.2%. The mean percentage of CD34 positive cells was 1.5%; SD 0.7%. Our results showed further that the frequency of cell populations, of which the presence is restricted to the bone marrow (e.g., CD34+ progenitor cells), is influenced by the degree of peripheral blood admixture. Between the total immature cells and purity of the bone marrow, there was a significant positive correlation demonstrated, whereas a negative correlation was found between the percentages of both lymphocytes as monocytes and the purity of the bone marrow. Conclusions: With a single tube-staining panel, we obtained reference values for flow cytometric assessment of all relevant leukocyte populations present in bone marrow that can be used as a frame of reference for better recognition of individuals with abnormal hematopoiesis. In addition, we have demonstrated the influence of the degree of peripheral blood admixture in the bone marrow aspirates on those reference values. © 2008 Clinical Cytometry Society [source] | |||||||||||||||||||||||||||||||||||||||||||