Cient Of Variation Research Articles

Agro-Morphological Characterization and Genetic Dissection of Linseed (Linum usitatissimum L.) Genotypes

Linseed is a multipurpose crop and the crop needs further improvement to increase production and yield due to its high value and demand. This study aimed to assess the extent and pattern of genetic variability of forty linseed genotypes based on diverse agro–morphological and yield attributes. The field experiment was conducted following a Randomized Complete Block Design with three replications. Linseed germplasm showed a wide range of phenotypic expression, genetic variability and heritability for 30 studied traits. A low to high phenotypic coeffi- cient of variation (PCV) and genotypic coefficient of variation (GCV) were observed. The lowest genotypic (σ2 g) and phenotypic variances (σ2 p) were found in capsule diameter (CD), length of calyx (LC), capsule length (CL), seed length (SL), and seed breadth (SB). High broad-sense heritability (h2b) with high genetic advance as a percentage of mean (GAM) were observed in days to germination started (DGS), days to 80% emergence (DE), plant height at 28 and 40 DAS, number of flowers (NFPP), filled capsules (NFCPP) and yield per plant (YPP) indicating additive gene action exists for these characters. Hierarchical cluster analysis separated 40 genotypes into five clusters, where Clusters I to V assembled with 13, 4, 4, 5 and 14 genotypes, respectively. Considering yield and yield attributes, Cluster-IV (G3, G4, G6, G10 and G31) genotypes showed promising while, Cluster-II (G2, G16, G35, G36) and Cluster-III (G1, G33, G39 and G40) genotypes were dominant on plant morphological traits. Based on principal component analysis (PCA), few characters such as YPP, NFPP, NFCPP, days to first flowering and capsule formation, early emergence, days to branch initiation and plant heights at different growth stages revealed important and effective traits for consideration in the selection of linseed breeding programs.

Impact of new Rexod® injection form on blood microcirculation in rat skin

Background. Free radical oxidation underlies many morbid processes in various organs and tissues, including skin. A major antioxidant preventing the free radical impact is superoxide dismutase (SOD). A particularly valued SOD-containing agent is recombinant human SOD, Rexod, possessing a wide spectrum of medical applications in form of lyophilisate. Marketing of a new Rexod® injection preparation in form of solution requires research into its properties, including the impact on blood microcirculation in skin, especially with the lack of relevant clinical trials.Objectives. Evaluation of anticipated positive effects of the new injection form of Rexod® on blood microcirculation in rat skin.Мethods. The new Rexod® preparation impact on blood microcirculation in skin was studied with laser Doppler fl uometry by recording the following non-oscillatory parameters of the basal blood fl ow: microcirculation (MC), mean squared deviation (MSD) and coeffi cient of variation (CV). Blood fl ow fl uctuations were measured in a wavelet analysis at different frequency bands: 0.0095–0.02, 0.02–0.046, 0.07–0.15, 0.15–0.4 and 0.8–0.16 Hz corresponding to endothelial (Ae), neurogenic (An), myogenic (Am), respiratory (Ar) and pulse (Ap) rhythm amplitudes, respectively.Results. The new Rexod® injection preparation at a dose of 8000 U/kg after 15 min of intraperitoneal administration in rats caused a statistically signifi cant (p < 0.05) increase in the blood fl ow fl uctuation amplitudes Ae (43.1%), An (43.4%), Am (60.8%), Ar (58.3%) and Ap (32.0%) compared to the control group. Because the Ae fl uctuations coincide with nitric oxide (NO) emission episodes, such a growth indicates an elevated NO excretion by endothelial cells leading to endothelium-dependent vasodilation. The observed changes in blood microcirculation in skin are also associated with higher integral values of the basal blood fl ow, MC (33.4% increase), MSD (14.0%) and CV (27.6%), although only MC and CV values were statistically signifi cant (p < 0.05). The results obtained suggest that the new injection form of Rexod® stimulates endothelial NO excretion, exerts adrenergic relaxation in smooth muscle cells of arteriolae and arteriovenular anastomoses, reduces precapillary sphincter and arteriolar contractility through Ca2+-dependent muscle relaxation, affects respiratory modulation of the venular blood microcirculatory compartment and vegetative cardiac support, intensifi es arterial blood fl ow by increasing the cardiac output.Conclusion. Application of the new Rexod® injection form improves blood microdynamics in rat skin via stimulating endothelium-dependent and independent vasodilatation and endothelial metabolism, decelerating adrenergic vasomotor activity and peripheral microvascular resistance. These processes in coupling improve blood fl ow to nutritive microvascular bed and normalise venular outfl ow. Our results provide further insights into pharmacodynamics of recombinant human SOD (Rexod).

Assessment of the functional state of the microvasculature in children with diabetes mellitus type 1

Objective: to assess the functional state of the microvasculature in children with diabetes mellitus type 1 (DM type 1).Materials and methods: 63 children with a verifi ed diagnosis of diabetes mellitus type 1 were examined. Th e control group consisted of 30 practically healthy children. Methods: clinical, paraclinical (determination of glycated hemoglobin level, study of microcirculation indicators using laser Doppler fl owmetry (LDF), statistical.Results: microcirculatory disorders accompanying the course of diabetes mellitus type 1 depending on the length of illness were identifi ed. In children with diabetes mellitus type 1 with standing less than 3 years an increase in the average modulation of blood fl ow mainly due to passive regulation mechanisms and the predominance of hypera adaptation in assessing the functional states of microcirculation of varying severity with an increase in the energy of oscillatory processes were observed. Signs of non-nutritive hyperemia in the zone rich in arteriovenous anastamoses and a decrease in perfusion due to an increase in perfusion fl uctuations and coeffi cient of variation in the distal extremities, as well as a decrease in amplitudes in the active tone-forming range, a gradual decrease in the energy of oscillations and randomness criteria were diagnosed with standing in the duration of the disease.Conclusions: disorders in children with diabetes mellitus type 1 microcirculatory detected using LDF are staged. Th e contribution of non-nutritive blood fl ow to microcirculation increases as the disease progresses, which leads to tissue hypoxia. Evaluation of the combination of energy, information and non-linear parameters of the oscillatory component of the blood flow allows you to identify the type of functional state in the microcirculation system.

YIELD VARIABILITY OF GRAIN CROP VARIETIES IN THE CONDITIONS OF THE STEPPE ZONE OF WESTERN SIBERIA

The work presents the results of research into the yield and quality of grain obtained from crop varieties of different maturity types, namely spring common wheat varieties (mid-early Pamyati Aziyeva, mid-late Baganskaya 95 and Omskaya 28), spring barley (early-ripening Bagan, mid-ripening Acha and Signal) and spring oats (early-ripening Krasnoobsky, mid-ripening SIG, mid-late Ural 2). The study was conducted in the conditions of the steppe zone of Western Siberia (North Kulunda), the climate of which is extremely continental, and is characterized by signifi cant variability of agrometeorological conditions of the vegetation period by years and a drought during the fi rst half of summer. It was established that sowing of midripening and mid-late varieties of wheat and barley resulted in the increase of the grain yield by 0.47-1.07 t/ha or by 24-30%, compared with the more early-ripening varieties. Among various biotypes of oats, the highest yields of grain were formed by sowing of the mid-ripening variety, which was by 0.60-0.87 t/ha or 19-30% higher than the early and mid-late varieties, whereas the highest yield of green mass was achieved by sowing of the mid-late variety. All varieties of barley, oats and mid-early wheat were characterized by signifi cant variability in grain yields by years (with coeffi cient of variation being 24-38%), while midlate varieties of wheat were characterized by medium or small variability in grain yields (coeffi cient of variation being 3-12%). The content of crude gluten in the grain of wheat varieties varied considerably depending on agrometeorological conditions (coeffi cient of variation being 20-25%). On average, over the years of research, the highest content of gluten (34.0%) was in the grain of the mid-early variety Pamyati Aziyeva, the lowest content (27.4%) was in the mid-late Baganskaya 95. The maximum amount of crude gluten in the wheat grain (33.6-40.0%) was observed in the dry year, the minimum (19.9-26.4%) was in the year with favorable humidity. The content of crude protein in the barley grain varied in the experiment from 11.6 to 14.9% (coeffi cient of variation being 9-14%) and did not differ signifi cantly by varieties (12.5-12.9%). The greatest amount of crude protein in the grain of all varieties of barley (13.7-14.9%) was recorded in the dry year.

INFLUENCE OF THE PROCESSING STEPS ON CASHEW NUT QUALITY

Cashew nuts have high nutritional value. This nut providesmacronutrients, micronutrients and a large variety of antioxidantssuch as phenolic compounds. There are losses in some compoundsduring the processing of fruits and there are very few studies on thisaspect. Given the above, this research aimed to determine the eff ectof the processing steps on cashew nut characteristics with emphasison total antioxidant activity. Signifi cant diff erences were observedbetween the processing steps for all the chemical and physicalchemicalcharacteristics studied. Cashew nuts contained high levelsof lipids and energy, low content of moisture and water activity andmedium content of phenolic compounds (51.33 GAE/100 g) andantioxidant activity by the ABTS•+ radical (6.49 μM Trolox/g) at theend of the processing. With regard to the total antioxidant activity,it was observed that the ABTS•+ radical method can be consideredappropriate to measure the antioxidant activity of cashew nuts, sincethe results presented lower coeffi cients of variation and expressproportionate results to other methods.

A Computational Approach for Testing Equality of Coefficients of Variation in k Normal Populations

In this article, a testing procedure based on computational approach testis proposed for the equality of coe¢ cients of variation in k normal populations. We compare this procedure to some of the existing tests; the likelihood ratio, modi ed Bennett’s, score, generalized p-value tests in terms of the estimated type I error rates and powers by using Monte Carlo simulation. Furthermore, applications of these tests are given on a real dataset. Keywords: Computational approach test, Generalized p-value test, Likelihood ratio test, Modi ed Bennett’s test, Score test 2000 AMS Classi cation: 62F03, 65C05, 65C60, 62E17

Inference for the Normal Mean with Known Coefficient of Variation

Inference for the mean of a normal distribution with known coefficient of variation is of special theoretical interest be- cause the model belongs to the curved exponential family with a scalar parameter of interest and a two-dimensional minimal sufficient statistic. Therefore, standard inferential methods cannot be directly applied to this problem. It is also of practical interest because this problem arises naturally in many environmental and agriculture studies. In this paper we proposed a modified signed log likelihood ratio method to obtain inference for the normal mean with known coeffi- cient of variation. Simulation studies show the remarkable accuracy of the proposed method even for sample size as small as 2. Moreover, a new point estimator for the mean can be derived from the proposed method. Simulation studies show that new point estimator is more efficient than most of the existing estimators.

Spatial and temporal variation of extremely low minimum temperatures in Hungary during the period between 1951 and 2010

For this study, data of 16 meteorological stations have been processed over a period of 60 years with the purpose to reveal the spatial and temporal structure of the frequencies of absolute extreme minima in Hungary with special reference to the surmised global rise of temperatures on a worldwide scale. In the main areas of fruit growing, the monthly or seasonal absolute temperature maxima and minima are presented during the 60 year-long period and projected on the geographical map. For the main fruit- and vegetable growing regions the probability of winter- and late frosts is of prime interest. The time series of extreme temperatures though did not prove signifi cant changes over the period observed, but the information upon changes and their tendencies is a precious tool being utilised in planning, choice of adequate varieties for a longer period of time in the future. The deleterious winter frosts experienced in fruit production is not a consequence of a sole drop to a minimum temperature, but of an earlier period of mild temperatures during the winter, which sensibilised the trees. Frequent and extreme variations of temperatures may cause troubles at any time during the year and reduce the yields conspicuously. We ought to get familiar with the hazards of our climate and fi nd optimal solutions to mitigate the damages expected. The seasonal and monthly distribution projected on the geographical map we can follow up also the spatial relations and the signifi cance of their occurrence. Coeffi cients of variation between meteorological happenings at different localities facilitate the calculation of the probability of risks on the surrounding areas.

Aliquoting on the centrifugal microfluidic platform based on centrifugo-pneumatic valves

We present a new method for aliquoting liquids on the centrifugal microfluidic platform. Aliquoting is an essential unit operation to perform multiple parallel assays (''geometric multiplexing'') from one individual sample, such as genotyping by real-time polymerase chain reactions (PCR), or homogeneous immunoassay panels. Our method is a two-stage process with an initial metering phase and a subsequent transport phase initiated by switching a centri- fugo-pneumatic valve. The method enables aliquoting liquids into completely separated reaction cavities. It includes precise metering that is independent on the volume of pre- stored reagents in the receiving cavities. It further excludes any cross-contamination between the receiving cavities. We characterized the performance for prototypes fabricated by three different technologies: micro-milling, thermoforming of foils, and injection molding. An initial volume of *90 ll was split into 8 aliquots of 10 ll volume each plus a waste reservoir on a thermoformed foil disk resulting in a coeffi- cient of variation (CV) of the metered volumes of 3.6%. A similar volume of *105 ll was split into 16 aliquots of 6 ll volume each on micro-milled and injection-molded disks and the corresponding CVs were 2.8 and 2.2%, respectively. Thus, the compatibility of the novel aliquoting structure to the aforementioned prototyping and production technolo- gies is demonstrated. Additionally, the important question of achievable volume precision of the aliquoting structure with respect to the production tolerances inherent to each of these production technologies is addressed experimentally and theoretically. The new method is amenable to low cost mass production, since it does not require any post-repli- cation surface modifications like hydrophobic patches.

Evidence for a Twelfth Large Earthquake on the Southern Hayward Fault in the Past 1900 Years

We present age and stratigraphic evidence for an additional paleoearth- quake at the Tyson Lagoon site. The acquisition of 19 additional radiocarbon dates and the inclusion of this additional event has resolved a large age discrepancy in our earlier earthquake chronology. The age of event E10 was previously poorly con- strained, thus increasing the uncertainty in the mean recurrence interval (RI), a critical factor in seismic hazard evaluation. Reinspection of many trench logs revealed sub- stantial evidence suggesting that an additional earthquake occurred between E10 and E9 within unit u45. Strata in older u45 are faulted in the main fault zone and overlain by scarp colluviums in two locations. We conclude that an additional surface- rupturing event (E9.5) occurred between E9 and E10. Since 91 A.D. (40 yr, 1σ), 11 paleoearthquakes preceded the M 6:8 earthquake in 1868, yielding a mean RI of 161 65 yr (1σ, standard deviation of recurrence intervals). However, the standard error of the mean (SEM) is well determined at 10 yr. Since ∼1300 A.D., the mean rate has increased slightly, but is indistinguishable from the overall rate within the uncertainties. Recurrence for the 12-event sequence seems fairly regular: the coeffi- cient of variation is 0.40, and it yields a 30-yr earthquake probability of 29%. The apparent regularity in timing implied by this earthquake chronology lends support for the use of time-dependent renewal models rather than assuming a random process to forecast earthquakes, at least for the southern Hayward fault. Online Material: Twelve-event Oxcal model for paleoearthquakes of the Hayward fault.

Determination of nonsteroidal anti-inflammatory drugs in human plasma by LC-MS-MS with a hydrophilic polymer column

Six nonsteroidal anti-inflammatory drugs (NSAIDs) in human plasma samples were analyzed by liquid chromatography (LC)-electrospray ionizationtandem mass spectrometry (MS-MS) using a hydrophilic polymer column (MSpak GF-310 4B), which enabled direct injection of crude biological samples. Separation of the six NSAIDs, alminoprofen, flurbiprofen, ibuprofen, pranoprofen, tiaprofenic acid, and zaltoprofen, was carried out using gradient elution with 10 mM ammonium acetate/acetonitrile. The mass spectra obtained by LC-single stage MS showed base peak ions due to [M+H]+ for alminoprofen, zaltoprofen, tiaprofenic acid, and pranoprofen, and [M-H]- for ibuprofen and flurbiprofen. Product ions were produced from each [M+H]+ or [M-H]- ion in the tandem mode. Quantitation was performed by multiple reaction monitoring with switching from positive to negative ion mode and vice versa. All drugs spiked into plasma showed recoveries of 77.0%–88.2%. The regression equations for the six drugs showed excellent linearity in the range of 0.01–25 μg/ml of plasma, and limits of detection were in the range of 0.002–0.005 μg/ml. Limits of quantitation were 0.01–0.02 μg/ml. Intraday and interday coeffi cients of variation for all drugs in plasma were not greater than 8.1%. The accuracy of quantitating the six drugs was in the range of 94.5%–110%. Data obtained from actual determinations of the levels of alminoprofen, pranoprofen, and ibuprofen in human plasma after oral administration are also presented.

A Note on the Calculation of Intrasubject Coefficient of Variation in Bioequivalence Trails

Bioequivalence studies are generally performed as crossover studies and, therefore, information in the Intrasubject Coef fi cient of Variation (CV) is needed for sample size planning. Recently, a confusing point was noticed in calculating the Intrasubject Coef fi cient of Variation (CV) in crossover studies under the additive model (i.e. under normality assumption and the multiplicative mode (i.e under logarithmic distribution). The aim of this paper is to clarify this confusion. Methods used in calculating the Intrasubject Coef fi cient of Variation (CV) are reviewed in this paper from a statistical point of view.

Tamanho e forma de parcela em experimentos com morangueiro cultivado em solo ou em hidroponia

O objetivo deste trabalho foi estimar a forma e o tamanho de parcela ótimos para ensaios com a cultura do morangueiro (Fragaria x ananassa) em cultivo hidropônico e em solo. Foram conduzidos dois, experimentos, um em cultivo convencional no solo, em túneis baixos, e outro em cultivo hidropônico. Em cada experimento, avaliaram-se os efeitos do tamanho e do formato das parcelas sobre a precisão experimental. Cada planta foi considerada uma unidade básica, e o número de unidades básicas por parcela variou de 1 (48 parcelas) a 24 (duas parcelas). Foram ajustadas funções para a determinação do coeficiente de variação entre as parcelas e para a determinação da variância por unidade básica entre as parcelas. O cultivo no solo apresentou maior variabilidade experimental que o cultivo hidropônico. O aumento no número de plantas por parcela causou redução acentuada na variabilidade experimental, especialmente quando se usou o formato de parcela retangular. O tamanho ótimo estimado das parcelas é de dez plantas, no cultivo com solo, e de seis plantas, no cultivo hidropônico.

Validation of a method for simultaneous determination of tocopherols and tocotrienols in cereals using Normal Phase HPLC

A method for the simultaneous determination of tocols (α-, β-,γ-, δ-tocopherols and α-, β-,γ-, δ-tocotrienols) in cereals using Normal Phase-HPLC (Merck; column LiChroCART 250-4, Lichrospher Si 60, 5 μm) with fl uorescent detection (Ex290 nm/Em350 nm) was validated. A mixture of hexane, ethyl acetate and acetic acid (97.3:1.8:0.9, v/v/v) was used as the eluent (1.6 ml/min). The analyses were performed after spectrophotometric standardization of standard ethanol solutions. The residual coeffi cients of variation for the regression equation y= ax 2 + bx + c were 0.001-3.8%, with r 2 >0.999. The limit of quantitation was 0.05 mg/kg, the upper limit of determination range from 40 to 60 mg/kg, repeatability 6.2-11.8%, and reproducibility 8.7-18.4%. Uncertainty of the method (P≤0.05), estimated for the analyses performed in replicate, ranged from 28.9 to 85.9% for the tocol concentration of 0.05-0.80 μg/ml and from 14.7 to 27.3% for the concentrations above 0.80 μg/ml. Recovery was 93.3-103.1%. The analytical method described is precise, fast and inexpensive.

Free light chains

Those of us ‘of a certain age’ have seen huge changes in the way labs work during our careers. Mattingly cortisols, Lieberman Burchard reagent for cholesterol and Kober reagent for oestriols are nowhere to be found in a modern Clinical Chemistry Lab. Bence Jones protein (BJP), however, has stood the test of time. It is the earliest described ‘tumourmarker’and still provides a high index of suspicion for B-cell malignancy. Henry Bence Jones described a precipitate that was formed on the addition of nitric acid to urine. This precipitate redissolved on heating and formed again on cooling and we now know that it is a protein. It is rather humbling that all Bence Jones had was a bit of acid and a £ame to make a discovery that is still in the common phrase book of pathologists around the world. Today, we ask for serum and urine samples to investigate patients with suspected B-cell malignancy and we use sensitive and reliable electrophoretic techniques to look for the presence of monoclonal proteins, to con¢rm clonality and to identify the heavy and/or light chain types of the monoclonal proteins. However, over the last few years there have been suggestions that this investigation process needs to be updated and in particular, checking urine for BJP should be a thing of the past! In 2001, Bradwell et al. reported the development of a sensitive automated immunoassay for immunoglobulin (Ig) free light chains. The FREELITE test measures free k and free l light chains and, because it is reported that k/l ratio remains normal except in the presence of monoclonal plasma cell proliferations, Katzmann et al. use the calculated k/lratio to infer amonoclonal excess of one particular light chain. There has been considerable interest in this approach for the investigation of patients with suspected and con¢rmed B-cell dyscrasias. However, as with any new test, we have to establish that it is better than the existing tests.We need to decide, based on our knowledge and experience, whether the test can do what we ask of it.We need to thoroughly evaluate it, using the populations that would normally be investigated with that test. Finally, we need to de¢ne when and where and how it should be used. So before we decide to radically change our lab practices for the investigation of B-cell malignancy, wemust look verycarefullyat the FREELITE assays and assess its validity at both analytical and clinical levels. First, a reminder of basic physiology; we all produce small amounts of polyclonal free light chains as a result of normal B-cell function. These pass readily from the blood through the glomerulus and we can see them in normal urine by sensitive immuno¢xation. In patients with renal disease or an underlying in£ammatory process or even in the elderly, the production or excretion of free light chains can increase. In some urine samples the free light chains are seen as an oligoclonal or ladder pattern but they are not BJP. Free light chains can be monoclonal, oligoclonal or polyclonal but BJP consists of only monoclonal free light chains. Unfortunately, there is no antiserum available that has the capacity to distinguish monoclonal Igs from polyclonal Igs (or monoclonal light chains from polyclonal light chains) in serum or in urine.We know this from our routine Ig concentrations on patients with paraproteins and we see it in external quality assurance (EQA) results. Monoclonal proteins can behave strangely in immunoassay even when using highly speci¢c and puri¢ed antiserum. For example, an IgG concentration of 5 or 15 g/L or even of 50 g/L can all be due to polyclonal IgG, monoclonal IgG or oligoclonal IgG. The concentration does not tell us about the clonality of the IgG. Interpreting the IgG concentration with the IgA and IgM concentrations does not help much -the electrophoretic pattern is essential for assessing the clonality of the quantitative Ig results. Monoclonal Igs do not behave like polyclonal Igs in immunonephelometric or immunoturbidimetric assays. The reasons for this are varied but include marked diierences between the polyclonal protein used as the antigen for the antibody production, diierences between antigenicity of the monoclonal protein and the standard used to calibrate the assay and the marked variability in dilution curves for individual paraproteins. The wide range of possible concentrations of monoclonal proteins also makes the inclusion of robust antigen excess checks vital for quantitative assays where monoclonal proteins may be seen. Overall, the results given in immunoassays for monoclonal Igs generally do not provide an accurate quanti¢cation. We assess broad assay reliability by participation in EQA.The FREELITE assay is produced byonly one companyand the reagents and standards are from the same source. However, the results generated in the EQA scheme show dramatically high coe⁄cients of variation -across all the assays (and the ratio), over many distributions, across all the analytical platforms and

Identification and quantitative determination of 5-methoxy-N,N-di-n-propyltryptamine in urine by isotope dilution gas chromatography-mass spectrometry

A simple method for analysis of 5-methoxy-N,N-di-n-propyltryptamine (5-MeO-DPT) in urine has been developed using gas chromatography-mass spectrometry (GC-MS) with tetradecadeuterated 5-MeO-DPT as internal standard, which is useful for discrimination from 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT). These tryptamine designer drugs were extracted from urine with Extrelut, and derivatized with trifl uoroacetic anhydride prior to GC-MS analysis. The recovery of 5-MeO-DPT from urine was 90.7%; the calibration curve showed linearity in the range of 0.01–2.0 μg/ml. When urine samples containing two different concentrations (0.1 and 1.0 μg/ml) of 5-MeO-DPT were analyzed, the coeffi cients of variation for intraday and interday testing ranged from 3.11% to 5.82%. The established method was applied to an acute poisoning case in which 5-MeO-DIPT abuse had been suspected. Unexpectedly, 5-MeO-DIPT could not be detected, but 5-MeO-DPT was found in the subject’s urine and in an aqueous sample seized upon investigation of the poisoning; the electron-impact ionization and chemical ionization mass spectra well agreed with those of authentic 5-MeO-DPT. The concentration of 5-MeO-DPT in urine of this case was 0.37 μg/ml. Although several reports have appeared describing poisoning cases of 5-MeO-DIPT, which carries the street name “Foxy,” to our knowledge, this is the first report of GC-MS analysis of 5-MeO-DPT and demonstration of its use in a poisoning case.

Low back pain and psychosocial factors in bus drivers

Objective: The objective of this study was to evaluate the prevalence of low back pain among bus drivers and to investigate the existence of a relationship between low back pain and psychosocial factors. Methods: We used an epidemiologic self-administered questionnaire, validated and adapted from the Quebec Back Pain Disability Scale. The sample included 78 male bus drivers, with mean age of 32.5 years. Results were analyzed through descriptive statistical methods (mean, median, standard deviation, standard error and coeffi cient of variation). Inferential analyses were performed with the Kolmogorov-Smirnov test, to analyze normality and with the Spearman correlation to determine the correlation among variables, with a confi dence level of p<0.05. Results: Low back pain showed a prevalence of 33.4%, and a low average correlation was observed among the variables. Conclusion: Around 34% of urban bus drivers reported low back pain, and the variables analyzed showed medium low correlation.

HbA1c or glucose for diabetes diagnosis?

This edition of the Annals contains an article by Geberhiwot et al. describing how HbA1c measurement may help avoid unnecessary oral glucose tolerance tests (OGTTs) in the diagnosis of type 2 diabetes. The use of HbA1c to diagnose diabetes is certainly appealing. It would obviate the need for the patient to attend testing while fasting and, if an OGTT was required, would address the problem associated with poor reproducibility of the 2 h glucose value. Thus, from both a patient and health-care provider perspective, it would be a muchmore convenient wayof testing for the disease. There is also an argument that HbA1c testing may be a more physiological assessment of glucose intolerance than the arti¢cial conditions of the OGTT. However, one of the obvious di⁄culties in solely using HbA1c as a substitute for the OGTT is that it compares a single test with a condition which can be diagnosed using two diierent criteria, namely the fasting plasma glucose (FPG) concentration and the 2 h value. We know that in some individuals -such as obese subjects -diabetes is more likely to be diagnosed on the FPG result, while in others -such as the elderly -it is more likely to be due to a diagnostic 2 hvalue. Sowhile the FPG cut-oi of 7.0mmol/L was chosen because it roughly corresponded with a 2 h value of 11.1mmol/L, nearly a third of Europeans with diagnostic 2 h values have ‘normal’ (p6mmol/L) FPGs, simply because they are a less obese population than the ones from which the new diagnostic criteria were established. This in turn means that the utility of HbA1c as a screening test for diabetes could vary depending on the demographics of age or weight in the particular population studied. Not that this has prevented there being numerous previous studies designed to investigate the possibility, or otherwise, of using HbA1c for this purpose. A metaanalysis of 34 studies con¢rmed that while an HbA1c result above the upper reference limit can be relatively speci¢c for glucose intolerance, it is not especially sensitive. In other words, a raised HbA1c is likely to indicate developing or overt glucose intolerance, but a ‘normal’ value does not exclude it. This is consistent with studies into the biological variability of HbA1c, which have found that non-diabetic subjects hover closely around a ‘set point’ within the 4--6% HbA1c reference interval. As a consequence, a subject with a usual HbA1c of 4% would need to abnormally increase his/her glycation rate by 50% to match another nondiabetic subject with an HbA1c of 6%. It is therefore not surprising that there can be overlap between the HbA1c values of diabetes patients with those of nondiabetic subjects. Likewise, it is also not unexpected that a ‘high-normal’ (5.5--6%) HbA1c can predict diabetes onset, since subjects with these results are likely to be a mixture of those who ordinarily have these concentrations together with others who are progressing to diabetes from lower initial values. Undoubtedly aware of these di⁄culties, Geberhiwot et al. have not attempted to use HbA1c as a screening test in its own right, but have rather sought to combine it with FPG to try to avoid unnecessary OGTTs. Eiectively, therefore, they are using glycated haemoglobin as a surrogate for the 2 h glucose concentration. There is certainly evidence that HbA1c correlates at least as well with post-prandial glucose excursions as it does with pre-meal glucose, and, together with the speci¢city of high HbA1c values for diabetes, the test has been used by them to triage the requirement for the laborious OGTT. At least some of the reasons that we are still debating the use of HbA1c in diagnosis (nearly three decades after its proven use in patients with established diabetes) relate to the analytical and inherent limitations of the test. Leaving aside the current HbA1c standardization/harmonization debate, there remain issues around individuals with abnormal haemoglobins and anaemias, especially when the latter is secondary to haemolysis or iron de¢ciency. In addition, from an analytical perspective, HbA1c is still not the most precisely measurable analyte, so an assay showing a 3% coe⁄cient of variation (CV) at the critical 6.0% HbA1c value can show a diierence in excess of 0.7% HbA1c within the same individual. Givenall these hurdles, it is di⁄cult to see howHbA1c will ever supplant (or even complement) the measurement of glucose while the latter test remains the single means by which the diagnosis is decided.To a clinician, near-certainty in making a diagnosis using HbA1c is not certain enough when deciding whether a person will nowhave an illness which has lifelong health, lifestyle and ¢nancial consequences for them. For this situation to change, HbA1c (a marker of glycation) would need to prove itself to be at least as good a predictor of diabetes complications as hyperglycaemia.

Comparative effects of diet and simvastatin on markers of thrombogenicity in patients with coronary artery disease

We investigated the effects of statin on lipoproteins, vasomotor function, serologic markers of infl ammation, plaque stability, thrombogenicity, and the mechanism of regulation compared with the Step I Diet.  Sixty-three patients with angiographically documented coronary artery disease were enrolled in this study. All patients were in Canadian Cardiovascular Society class I or II. All patients were taught and placed on the American Heart Association Step I Diet throughout the study period. Data on baseline characteristics of study participants and brachial artery endothelium-dependent reactivity, as well as lipoprotein levels, markers of infl ammation, and plaque stability in blood have been reported previously and are listed in Tables 1 and 2. 1 The 2 groups were age- and gender-matched. Mean age of patients was 62 years, and 13 of 32 patients were men. The risk factors were hypertension (68% vs 72%; diet and placebo group vs diet and simvastatin group, respectively), diabetes (23% vs 25%), and current smoking (35% vs 31%). The proportion of medications were -adrenergic blockers (81% vs 81%), calcium channel blockers (48% vs 47%), angiotensin-converting enzyme inhibitors (23% vs 28%), long-acting nitrates (81% vs 84%), and aspirin (84% vs 88%). We administered diet placebo (n 31) and diet simvastatin 20 mg/day (n 32) in a randomized order for 14 weeks in patients with coronary artery disease using a singleblind prospective randomized design. The study was approved by the Gil Hospital Institutional Review Board, and all participants gave written informed consent. Blood samples for laboratory assays were obtained at approximately 8:00 A.M. following an overnight fast after pretreatment and simvastatin for 14 weeks. The samples were immediately coded so that investigators performing laboratory assays were blinded to subject identity or study sequence. Assays for lipoproteins and plasminogen activator inhibitor type-1 (PAI-1) antigens were performed as previously described. 2 Tumor necrosis factor (TNF)-, matrix metalloproteinase (MMP)-9, tissue inhibitor of matrix metalloproteinase (TIMP)-1, C-reactive protein (CRP), fi brinogen, and antithrombin III were measured in duplicates by an enzyme-linked immunosorbent assay (R & D Systems, Minneapolis, Minnesota) and rate nephelometry (IMMAGE; Beckman Coulter, Brea, California) as previously described. 3–5 Tissue factor (TF) and tissue factor pathway inhibitor (TFPI) activity were measured in duplicate by actichrome assays (American Diagnostica, Greenwich, Connecticut) as previously described.5,6 All samples from the same patient (batch samples) were measured in blinded pairs on the same enzyme-linked immunosorbent assay kit to minimize run-to-run variability. The interassay and intraassay coeffi cients of variation were 6%. Data are expressed as mean SD or median (range 25% to 75%). After testing data for normality, we used Student’s paired t or Wilcoxon’s signed rank test to compare values between baseline and treatment

Seasonal variation in glycated haemoglobin in diabetics.

Good control of blood glucose concentration in insulin-dependent diabetics leads to fewer complications. Monitoring of glucose control is therefore central to the management of patients with diabetes. This is achieved both by the frequent measurement of blood glucose concentrations and by the measurement of blood glycated haemoglobin (sometimes referred to as haemoglobin A1c (HbA1c)). There have been a few isolated reports that glycated haemoglobin is subject to a seasonal variation in diabetics, both in children in Britain and in adults in Sweden. This is clearly important in interpreting changes in glycated haemoglobin in response to therapeutic interventions. Here we report that glycated haemoglobin in a British adult diabetic population is subject to seasonal variation. During a study investigating the effect of clinical glycated haemoglobin measurement on diabetic control (to be reported), it was noticed that there was an overall worsening of diabetic control (as assessed by glycated haemoglobin measurement) over the ®rst 6 months of the study (autumn 1995 to spring 1996), suggesting that there might be a systematic effect. Patients (both type 1 and type 2 diabetics) attending the diabetic clinic were therefore followed for a further 2 years. A total of 6721 results on 1295 mainly Caucasian patients [54% male, 51% type 1 diabetics aged 52+11 years, mean+standard deviation (SD)] were obtained using a dedicated cation exchange high-performance liquid chromatography (HPLC) system (the `Diamat’, Biorad Ltd, Hemel Hempstead, UK). Each patient provided an average of 5 2 samples (range 1±6, SD 2 3) at approximately 3-, 6or 12-month intervals over a 2-year period. The results (see Fig. 1) clearly show a seasonal variation, with a maximum in the spring (March, April, May) and a nadir in the autumn (September, October, November). The averages+SD for the autumn months of 1995, 1996 and 1997 during the study were 8 52+1 53 (n=783), 8 57+1 6 (n=695) and 8 51+1 6 (n=608). For the spring months of 1996 and 1997 they were 9 21+1 7 (n=623) and 9 04+1 7 (n=578). The differences between each autumn and each spring average glycated haemoglobin were all highly statistically signi®cant (P50 0001, Student’s unpaired two-tailed t-test). There is no reason to suppose that by chance more well controlled diabetics were seen in the spring than in the autumn, although if this were to be the case it would confound the results. The fact that two complete cycles of peaks and troughs were found also argues against this being a chance ®nding. During this period there was no change in the performance of the assay [the range of the monthly percentage coef®cients of variation (%CVs) for the low control at a glycated haemoglobin of 5 4% was 2 3±4 3, and for the high control at a glycated haemoglobin of 10 0% was 1 2±2 3]. These results are in broad agreement with previous studies in British children, which showed a peak in February and a trough in August, and in Swedish adults, which showed a peak in January and a trough in July, although the peaks and troughs observed in the present study occurred a little later. These results are most easily interpreted as there being a seasonal variation in blood glucose levels. It is interesting to note that the peak glycated haemoglobin found here was in the spring. Glycated haemoglobin is affected by the average of the blood glucose for about the previous 3 months. This would have extended into the previous winter months, the season of increased infections which would be expected to worsen diabetic control. Other seasonal factors, such as seasonal food availability, the amount of exercise undertaken or the seasonal changes in vitamin D levels, might also be important. These factors will necessarily vary from year to year, and so it is not surprising that the characteristics of the spring peaks are not identical. It has recently been shown in a cohort study of 21 healthy females that glycated Short Report Ann Clin Biochem 2001; 38: 59±60