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Blood Spots (blood + spot)
Kinds of Blood Spots Terms modified by Blood Spots Selected AbstractsDermoscopy provides useful information for the management of melanonychia striataDERMATOLOGIC THERAPY, Issue 1 2007Luc Thomas ABSTRACT:, The diagnosis of melanonychia striata is often difficult, and a biopsy of the nail matrix is required in doubtful cases. However, dermoscopic examination of the nail plate offers interesting information in order to better select the cases in which pathologic examination is indicated. In the case of brown longitudinal pigmentation with parallel regular lines, the diagnosis of nail apparatus melanocytic nevus could be made. On the other hand, the presence of a brown pigmentation overlaid by longitudinal lines irregular in their thickness, spacing, color, or parallelism is highly in favor of a melanoma. Gray homogeneous lines are observed in case of lentigo, lentiginoses, ethnic or drug-induced pigmentations, and in post-traumatic pigmentations. Blood spots are characterized by their round-shaped proximal edge and their filamentous distal edge and are highly suggestive of subungual hemorrhages. Dermoscopic examination of the free edge of the nail plate gives information on the lesion location; pigmentation of the dorsum of the nail plate is in favor of a proximal nail matrix lesion, whereas pigmentation the lower part of the nail edge is in favor of a lesion of the distal matrix. [source] A new rapid micromethod for the assay of phenobarbital from dried blood spots by LC-tandem mass spectrometryEPILEPSIA, Issue 12 2009Giancarlo La Marca Summary Advantages of dried blood spot include low invasiveness, ease and low cost of sample collection, transport, and storage. We used tandem mass spectrometry (LC-MS/MS) to determine phenobarbital levels on dried blood spot specimens and compared this methodology to commercially available particle enhanced turbidimetric inhibition immunoassay (PETINIA) in plasma/serum samples. The calibration curve in matrix using D5 -phenobarbital as internal standard was linear in the phenobarbital concentration range of 1,100 mg/L (correlation coefficient 0.9996). The coefficients of variation in blood spots ranged 2.29,6.71% and the accuracy ranged 96.54,103.87%. There were no significant differences between the concentrations measured using PETINA and LC-MS/MS (both had similar precision and accuracy) however, LC-MS/MS allows at least 1.5 times higher throughput of phenobarbital analysis and additionally offers ease of sample collection which is particularly important for newborns or small infants. [source] Human immunodeficiency virus serotyping on dried serum spots as a screening tool for the surveillance of the AIDS epidemicJOURNAL OF MEDICAL VIROLOGY, Issue S1 2006Francis Barin Abstract Many studies have demonstrated the utility of the dried blood spot (DBS) or dried plasma/serum spot (DSS) method for serological and molecular diagnosis of HIV infection. Here, we report on the description of a serotyping assay performed on DSS, and its application to a national surveillance program of HIV variants. We combined serotyping assays that we developed previously to discriminate between HIV-1 and HIV-2, between HIV-1 group O and HIV-1 group M, and between B and non-B subtypes of HIV-1 group M. The assays are based on antibody binding to either the immunodominant epitope of gp41 or the V3 domain of gp120 of these various types, groups and subtypes. Therefore, a unique enzyme-linked immunosorbent assay (ELISA) format applied to serum eluted from DSS allowed the simultaneous discrimination between infections caused by HIV-1 B, HIV-1 non-B, HIV-1 group O, and HIV-2. Together, this serotyping assay and an immunoassay for recent infection were used for a virological surveillance linked to the anonymous mandatory notification of HIV infection in France. The preliminary results of this virological surveillance allowed us to obtain estimates of the prevalence of the rare variants HIV-2 and HIV-1 group O. It also allowed identification of the two first cases of M/O dual infections reported outside the endemic group O region of the western part of equatorial Africa, and showed that non-B subtypes circulate widely in France, almost 50% of new HIV diagnoses in 2003 being due to these variants. J. Med. Virol. 78:S13,S18, 2006. © 2006 Wiley-Liss, Inc. [source] Increasing the uptake of hepatitis C virus testing among injecting drug users in specialist drug treatment and prison settings by using dried blood spots for diagnostic testing: a cluster randomized controlled trialJOURNAL OF VIRAL HEPATITIS, Issue 4 2008M. Hickman Summary., The objective of this study was to assess whether introducing dried blood spot testing can increase hepatitis C virus (HCV) diagnostic testing. A cluster randomized controlled trial was conducted. Sites were matched into pairs, with one site in each pair randomly allocated to receive the intervention (training and use of dried blood spot). Data were collected from all sites for 6 months before and 6 months after the start of the intervention. The participants were 22 specialist drug clinics and six prisons in England and Wales. The main outcome measure of this study was percentage point difference in individuals tested for HCV (the difference between the percentage of patients tested 6 months after and 6 months before the introduction of dried blood spot tests). Before the trial, 8% of patients at control and intervention sites had been tested for HCV, with 16 sites testing less than 5% of their caseload. The average percentage point difference between intervention and control sites was 14.5% (95% CI 1.3,28%, paired t -test, P = 0.03); with 13 of the 14 pairs contributing to the positive effect of the intervention (Wilcoxon matched-pairs signed-rank-test, P = 0.002). The size of the difference between intervention and control sites varied considerably. The study provides preliminary supporting evidence that dried blood spot testing may increase the uptake of HCV diagnostic testing, by increasing the opportunity for patients to be offered testing. Additional trials with a larger number of sites are justified, ideally in the context of drug and treatment policies that gave clearer priority (and targets) to infection control and testing. [source] Precursor ion scan profiles of acylcarnitines by atmospheric pressure thermal desorption chemical ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2008Giuseppe Paglia The fatty acyl esters of L-carnitine (acylcarnitines) are useful biomarkers for the diagnosis of some inborn errors of metabolism analyzed by liquid chromatography/tandem mass spectrometry. In this study the acylcarnitines were analyzed by atmospheric pressure thermal desorption chemical ionization using a commercial tandem mass spectrometer (APTDCI-MS/MS). The method is based on the precursor ion scan mode determination of underivatized acylcarnitines desorbed from samples by a hot desolvation gas flow and ionized by a corona pin discharge. During desorption/ionization step the temperature induces the degradation of acylcarnitines; nevertheless, the common fragment to all acylcarnitines [MH,59]+ is useful for analyzing their profile. APTDCI parameters, including angle of collection and incidence, gas flows and temperatures, were optimized for acylcarnitines. The experiments were performed drying 2,µL of an equimolar mixture of acylcarnitine standards on a glass slide. The specificity was evaluated by comparing product ion spectra and the precursor ion spectra of 85 m/z of acylcarnitines obtained by the APTDCI method and by electrospray ionization flow injection analysis (ESI-FIA). The method was also employed to analyze acylcarnitines extracted from a pathological dried blood spot and a control. The method enables analysis of biological samples and recognition of some acylcarnitines that are diagnostic markers of inherited metabolic diseases. The intrinsic high-throughput analysis of the ambient desorption ionization methods offers a new opportunity either for its potential application in clinical chemistry and for the expanded screening of some inborn errors of metabolism. Copyright © 2008 John Wiley & Sons, Ltd. [source] Dried blood spot sampling in combination with LC-MS/MS for quantitative analysis of small moleculesBIOMEDICAL CHROMATOGRAPHY, Issue 1 2010Wenkui Li Abstract The collection of whole blood samples on paper, known as dried blood spot (DBS), dates back to the early 1960s in newborn screening for inherited metabolic disorders. DBS offers a number of advantages over conventional blood collection. As a less invasive sampling method, DBS offers simpler sample collection and storage and easier transfer, with reduced infection risk of various pathogens, and requires a smaller blood volume. To date, DBS-LC-MS/MS has emerged as an important method for quantitative analysis of small molecules. Despite the increasing popularity of DBS-LC-MS/MS, the method has its limitations in assay sensitivity due to the small sample size. Sample quality is often a concern. Systematic assessment on the potential impact of various blood sample properties on accurate quantification of analyte of interest is necessary. Whereas most analytes may be stable on DBS, unstable compounds present another challenge for DBS as enzyme inhibitors cannot be conveniently mixed during sample collection. Improvements on the chemistry of DBS card are desirable. In addition to capturing many representative DBS-LS-MS/MS applications, this review highlights some important aspects of developing and validating a rugged DBS-LC-MS/MS method for quantitative analysis of small molecules along with DBS sample collection, processing and storage. Copyright © 2009 John Wiley & Sons, Ltd. [source] A new rapid micromethod for the assay of phenobarbital from dried blood spots by LC-tandem mass spectrometryEPILEPSIA, Issue 12 2009Giancarlo La Marca Summary Advantages of dried blood spot include low invasiveness, ease and low cost of sample collection, transport, and storage. We used tandem mass spectrometry (LC-MS/MS) to determine phenobarbital levels on dried blood spot specimens and compared this methodology to commercially available particle enhanced turbidimetric inhibition immunoassay (PETINIA) in plasma/serum samples. The calibration curve in matrix using D5 -phenobarbital as internal standard was linear in the phenobarbital concentration range of 1,100 mg/L (correlation coefficient 0.9996). The coefficients of variation in blood spots ranged 2.29,6.71% and the accuracy ranged 96.54,103.87%. There were no significant differences between the concentrations measured using PETINA and LC-MS/MS (both had similar precision and accuracy) however, LC-MS/MS allows at least 1.5 times higher throughput of phenobarbital analysis and additionally offers ease of sample collection which is particularly important for newborns or small infants. [source] Acute leukemias with ETV6/ABL1 (TEL/ABL) fusion: Poor prognosis and prenatal originGENES, CHROMOSOMES AND CANCER, Issue 10 2010Jan Zuna The ETV6/ABL1 (TEL/ABL) fusion gene is a rare aberration in malignant disorders. Only 19 cases of ETV6/ABL1 -positive hematological malignancy have been published, diagnosed with chronic myeloid leukemia, other types of chronic myeloproliferative neoplasm, acute myeloid leukemia or acute lymphoblastic leukemia (ALL). This study reports three new cases (aged 8 months, 5 years, and 33 years) of ALL with the ETV6/ABL1 fusion found by screening 392 newly diagnosed ALL patients (335 children and 57 adults). A thorough review of the literature and an analysis of all published data, including the three new cases, suggest poor prognosis of ETV6/ABL1 -positive acute leukemias. The course of the disease in the two pediatric patients is characterized by minimal residual disease monitoring, using quantification of both the ETV6/ABL1 transcript and immunoreceptor gene rearrangements. Eosinophilia could not be confirmed as a hallmark of the ETV6/ABL1 -positive disease. Studies of neonatal blood spots demonstrated that, in the child diagnosed at five years, the ETV6/ABL1 fusion initiating the ALL originated prenatally. © 2010 Wiley-Liss, Inc. [source] Molecular neonatal screening for homocystinuria in the Qatari population,HUMAN MUTATION, Issue 6 2009Johannes Zschocke Abstract We report the results of molecular neonatal screening for homocystinuria (cystathionine beta-synthase deficiency) in neonates of Qatari origin, developed in conjunction with a novel biochemical screening approach. DNA was extracted from dried blood spots (DBS); the prevalent Qatari CBS gene mutation p.R336C (c.1006C>T) and a second mutation were tested with specific TaqMan assays. Over a period of 2 years we screened 12,603 neonates and identified six affected neonates homozygous for p.R336C. There were 225 heterozygous carriers for p.R336C. One additional child with homocystinuria detected through biochemical screening was homozygous for a mutation not previously identified in Qatar. Homocystinuria in the Qatari population has an incidence of 1:1,800, the highest in the world and even higher than previously estimated. Allele frequency of the mutation p.R336C is approximately 1%, displaying a significant deviation from Hardy Weinberg equilibrium. In conclusion, first-line molecular neonatal screening is technically feasible and may be developed as an option for presymptomatic identification of genetic disorders caused by specific mutations or a limited number of prevalent mutations. However, sensitivity for the diagnosis of disorders caused by various mutations is limited even in a homogeneous population such as Qatar. Hum Mutat 30:1,2, 2009. © 2009 Wiley-Liss, Inc. [source] Rapid screening assay of congenital adrenal hyperplasia by measuring 17,-hydroxyprogesterone with high-performance liquid chromatography/electrospray ionization tandem mass spectrometry from dried blood spotsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 1 2002Chien-Chen Lai Abstract A rapid, simple, and specific method was developed for the diagnosis of congenital adrenal hyperplasia (CAH) from dried blood spots on newborn screening cards based on high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). The usefulness of 17,-hydroxyprogesterone (17OH-P) determination on dried filter-paper blood samples from patients with CAH caused by 21-hydroxylase deficiency was evaluated. The LC/MS/MS detection of 17OH-P was rapid, <4 min. The intra- and interday accuracy and precision of the method were <7%. Our procedure maintained good linearities (R2 > 0.992) and recovery rate (>83%). We used this new method to directly determine the 17OH-P levels in dried blood specimens from abnormal children of various ages, with a detection limit of 20 ng/ml (,240 pg), to avoid the time-consuming derivatization steps required by the gas-chromatography/mass spectrometry (GC/MS) method. Four dried filter-paper blood samples of CAH patients (three girls and one boy, 1,14 years old) were all quantified in an LC/MS/MS study and revealed high 17OH-P levels (>90 ng/ml). After treatment, all of the elevated 17OH-P levels either decreased or disappeared. Compared with CAH patients, 17OH-P was nearly undetectable (<20 ng/ml) in the normal infants by LC/MS/MS. This LC/MS/MS assay is not only useful for both diagnosis and monitoring of treatment of CAH in all other age groups, it also can be used as a screening test for CAH infants. In this study, we provided the first data on 17OH-P in dried blood specimens affected with CAH using HPLC/ESI-MS/MS. J. Clin. Lab. Anal. 16:20,25, 2002. © 2002 Wiley-Liss, Inc. [source] Thiopurine S -methyltransferase (TPMT) genetic polymorphisms in Mexican newbornsJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 6 2009A. González-del Angel MD Abstract Background:, Thiopurine S -methyltransferase (TPMT) is involved in the toxicity and therapeutic efficacy of thiopurine drugs, and its gene exhibits genetic polymorphisms that differ across diverse populations. Four TPMT polymorphisms (TPMT*2, *3A, *3B and *3C) account for 80,95% of alleles that cause reduced enzyme activity. To date, only a single study in the Mexican population involving 108 individuals has been performed, but the regional and ethnic origin of this population was not described. Accordingly, information about the TPMT polymorphism in the Mexican population is limited. Objective:, To determine the TPMT allele and genotype frequencies in a sample of newborns from Mexico City. Methods:, Three hundred and sixty DNA samples from unrelated, anonymous individuals were obtained from dried blood spots collected on filter paper as part of the Newborn Screening National Program. Allele-specific polymerase chain reaction for the TPMT*2 allele and PCR restriction fragment length polymorphism for TPMT*3A, TPMT*3B, TPMT*3C alleles were used to determine the respective allelic and genotypic frequencies. Results and Discussion:, Of 720 TPMT alleles analysed, 49 (6·81%) were deficiency alleles. The most common deficiency allele was TPMT*3A (5·69%), followed by TPMT*3C (0·56%), TPMT*3B (0·28%) and TPMT*2 (0·28%). Fourty-five newborns were heterozygous for one mutant allele (12·5%) and two showed a genotype with two deficiency alleles (0·56%). Despite its unique ethnic composition, our Mexican population exhibited variant allele frequencies that were similar to some Caucasian populations. Conclusion:, Our data suggest that approximately 1 in 180 persons born in Mexico City might have low or undetectable TPMT enzyme activity, a frequency that, overall, is somewhat higher than that reported for Caucasian populations generally (1 in 300). [source] Molecular analysis of the thiopurine S-methyltransferase alleles in Bolivians and TibetansJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 5 2005H.-F. Lu MT Summary Background:, Thiopurine drugs are used as immunosuppressant or cytotoxic drugs. Thiopurine S-methyltransferase (TPMT) methylates and thereby modulates the therapeutic and toxic effects of these drugs. The activity of TPMT is affected by genetic polymorphism of TPMT alleles, and these alleles have not been studied in Tibetans and Bolivians. Objectives:, To analyse the TPMT allelic frequencies in Tibetans and Bolivians. Methods:, We developed an inexpensive method for collecting blood and extracting genomic DNA. Genomic DNA was extracted from blood spots of 50 Tibetans and 115 Bolivians. The frequencies of allelic variants of TPMT gene (TPMT*1 to TPMT*8) were determined using polymerase chain reaction-restriction fragment length polymorphism technique. Results:, The allelic frequencies of TPMT*1 were 99 and 93·48% for Tibetans and Bolivians, respectively. The corresponding allelic frequencies of TPMT*3A were 0 and 6·52% and those of TPMT*3C were 1·0 and 0%. No TPMT*2, 3B, 3D, 4,8 were found in these two populations. Conclusions:, As with Caucasian populations, TPMT*3A is the most prevalent mutant allele in Bolivians. Our results may be of value in helping to guide the prescription of thiopurine drugs in these populations. [source] Effect of Slaughter Method on Postmortem Changes of Grass Carp (Ctenopharyngodon idella) Stored in IcestiJOURNAL OF FOOD SCIENCE, Issue 5 2005Rodrigo Scherer ABSTRACT: The effect of 2 slaughter methods (immersion in ice-water slurry and electrical stunning followed by ice slurry asphyxiation) on the quality of grass carp (Ctenopharyngodon idella) stored in ice for 20 d was evaluated using sensory and chemical analysis. Electricity immediately stunned the fish and did not induce blood spots in the flesh. Fish killed by electricity showed a faster initial rate of ATP degradation and entered into rigor mortis earlier, but did not show significant differences in the sensory score when compared with fish killed by immersion in ice-water slurry. Thus, no differences were observed in the shelf life of carps between the 2 slaughter methods evaluated. The limit for acceptability of grass carp stored in ice was around 13 to 16 d. Grass carp accumulated more inosine than hypoxanthine. K, Ki, P, Fr, and H values were highly correlated with storage time and with the TFRU sensory scores in both groups; these could be used to assess the freshness quality of grass carp. [source] Direct STR Amplification from Whole Blood and Blood- or Saliva-Spotted FTA® without DNA Purification,JOURNAL OF FORENSIC SCIENCES, Issue 2 2008Su Jeong Park Ph.D. Abstract:, The DNA purification step has been thought to be essential for typing of STR DNA. However, this process is time-consuming, and there is a risk of unexpected cross-contamination during purification. We report a new method for direct short tandem repeat (STR) amplification using a newly developed direct PCR buffer, AnyDirectÔ, which can amplify STR loci from whole blood and blood- or saliva-spotted FTA® cards without DNA purification. The autosomal and Y chromosomal STR loci were analyzed for whole blood and blood or saliva spots of random individuals, followed by comparison of the results with those of corresponding purified DNA. The results from whole blood and blood spots showed perfect concordance with those from purified DNA without allele or locus drop-out. However, in the case of saliva spots, no amplification or locus drop-out was observed in some of the samples, which offers a topic for further study. Additionally, some commercial hot-start DNA polymerases other than AmpliTaq Gold® DNA polymerase were also found to be compatible with this buffer system. Therefore, this direct PCR buffer was demonstrated to be useful for fast forensic DNA analysis or criminal DNA databases for which there is no need to store DNA samples. [source] Newborn screening in Fragile X syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 10 2008F. Tassone Background: Screening for the FMR1 mutations has been a topic of considerable discussion since the FMR1 gene was identified. However, Fragile X has not been recommended for newborn screening mainly because of the lack of an accurate screening test and of data on potential benefits. We have recently developed an improved Polymerase Chain Reaction (PCR) method for the identification of premutation and full mutation alleles for the FMR1 gene. Method: The method is inexpensive, accurate and quick and can be performed on a number of sample templates including, importantly, blood spots. We have applied this method for international screening. Specifically, we have screened 5267 anonymous blood spot samples from newborn males from the centre-northwest region of Spain. We have also used this technology to a pilot ,high risk' screening program of individuals with autism and/or intellectual disabilities and family members of a proband with fragile X initiated in Guatemala. This project is a prototype for future screening endeavours. Results: One important outcome from this study is that the frequency of premutation alleles (1 per 250) appears to be higher than previously reported. This is of importance, especially in view of the different phenotypic involvement observed in carriers of premutation alleles, including neurological problems such as FXTAS. Here, we present data on the frequency of premutation/full alleles found in this population and their size distribution. Conclusion: This project is a prototype for future screening endeavours. Results from our pilot program in both Spain and Guatemala will lend strong support for implementing this technology for rapid screening to a much larger scale population screening. [source] Fully automated liquid extraction-based surface sampling and ionization using a chip-based robotic nanoelectrospray platform,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2010Vilmos Kertesz Abstract A fully automated liquid extraction-based surface sampling device utilizing an Advion NanoMate chip-based infusion nanoelectrospray ionization system is reported. Analyses were enabled for discrete spot sampling by using the Advanced User Interface of the current commercial control software. This software interface provided the parameter control necessary for the NanoMate robotic pipettor to both form and withdraw a liquid microjunction for sampling from a surface. The system was tested with three types of analytically important sample surface types, viz., spotted sample arrays on a MALDI plate, dried blood spots on paper, and whole-body thin tissue sections from drug dosed mice. The qualitative and quantitative data were consistent with previous studies employing other liquid extraction-based surface sampling techniques. Published in 2009 by John Wiley & Sons, Ltd. [source] Increasing the uptake of hepatitis C virus testing among injecting drug users in specialist drug treatment and prison settings by using dried blood spots for diagnostic testing: a cluster randomized controlled trialJOURNAL OF VIRAL HEPATITIS, Issue 4 2008M. Hickman Summary., The objective of this study was to assess whether introducing dried blood spot testing can increase hepatitis C virus (HCV) diagnostic testing. A cluster randomized controlled trial was conducted. Sites were matched into pairs, with one site in each pair randomly allocated to receive the intervention (training and use of dried blood spot). Data were collected from all sites for 6 months before and 6 months after the start of the intervention. The participants were 22 specialist drug clinics and six prisons in England and Wales. The main outcome measure of this study was percentage point difference in individuals tested for HCV (the difference between the percentage of patients tested 6 months after and 6 months before the introduction of dried blood spot tests). Before the trial, 8% of patients at control and intervention sites had been tested for HCV, with 16 sites testing less than 5% of their caseload. The average percentage point difference between intervention and control sites was 14.5% (95% CI 1.3,28%, paired t -test, P = 0.03); with 13 of the 14 pairs contributing to the positive effect of the intervention (Wilcoxon matched-pairs signed-rank-test, P = 0.002). The size of the difference between intervention and control sites varied considerably. The study provides preliminary supporting evidence that dried blood spot testing may increase the uptake of HCV diagnostic testing, by increasing the opportunity for patients to be offered testing. Additional trials with a larger number of sites are justified, ideally in the context of drug and treatment policies that gave clearer priority (and targets) to infection control and testing. [source] Population-based retrieval of newborn dried blood spots for researching paediatric cancer susceptibility genesPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 5 2006Judith Klotz Summary We have demonstrated the feasibility of linking newborn blood spots, population-based cancer incidence data and birth certificate data. Incident cases of acute lymphocytic leukaemia and population-based controls were ascertained. We retrieved dried blood spot specimens, isolated and amplified DNA, and assayed the cancer susceptibility genes GSTT1 and GSTM1. The double null genotype was over-represented in the cases, consistent with previous reports based on other epidemiological methods. The design avoids issues of participation bias by cases and controls and can be used to investigate interactions of susceptibility genes and xenobiotics in semi-ecological studies. It can be useful for generating or testing hypotheses on associations of other paediatric illness and environmental contaminants. [source] Glutamic acid decarboxylase and IA-2 autoantibodies in type 1 diabetes: comparing sample substrates for autoantibody determinationsPEDIATRIC DIABETES, Issue 1 2000C Wasserfall Large-scale programs designed to assess risk for type 1 diabetes through serologic assessment of autoantibodies to recombinant ,-cell autoantigens are hampered by several limitations, including the methods for sample collection and assay performance, as well as the volume required for autoantibody determinations. The present study was designed to develop a low sample-volume, primary screening method for autoantibody detection of high specificity and sensitivity, and to determine the feasibility of dried blood spots collected on filter paper in serving as vehicles for such determinations. Autoantibodies to glutamic acid decarboxylase (GAD) and ICA512bdc (IA-2), both individually and in combination, were determined in persons with type 1 diabetes, healthy controls, or individuals with other autoimmune disorders. Autoantibody results for serum, plasma, and dried blood spots were compared. GAD, IA-2, and combined GAD/IA-2 autoantibodies were concordant in their measurement from minimal volumes of serum, plasma, and whole blood extracted from dried filter paper. The autoantibody levels from the dried blood spots were, however, lower than corresponding serum samples, and, as currently designed, failed to detect low-titer autoantibodies. Despite this limitation, screening for diabetes risk can be performed using small volumes of whole blood, serum, or plasma collected onto filter paper. These methodological improvements should simplify matters, reduce costs, and increase the efficacy of screening programs for type 1 diabetes. Further development of better substrates/methods for blood-specimen collection seems necessary to exploit the full potential of this and other autoantibody measurement strategies for screening large populations. [source] Original Article: Long-term stability of thyroid hormones and DNA in blood spots kept under varying storage conditionsPEDIATRICS INTERNATIONAL, Issue 4 2010Asmahan A. EL Ezzi Abstract Background:, Congenital hypothyroidism is screened using blood spotted on filter paper that may be transported from remote areas to central testing facilities. However, storage conditions and transportation may affect sample quality. Methods:, We examined long-term stability of thyroid-stimulating hormone (TSH) and thyroxin (TT4) in blood spotted on filter paper, which was stored at room temperature (RT), 4°C and ,20°C under continuous or intermittent power supply (six hours on and six hours off around the clock.) Hormone levels in the discs were measured periodically for up to ten years. Extraction of DNA from blood spots and polymerase chain reaction were performed. Results:, Our results showed that TT4 was stable for up to 6.1, 5.34 and 5.16 years when stored at ,20°C, 4°C and RT, respectively. TSH was stable for up to 2.7 years at RT, and for up to 6.5 and 4.1 years when stored at ,20°C and 4°C, respectively, under continuous power supply. However, under intermittent power supply, TSH was stable for up to 3.8 and 2.5 years when stored at 4°C and ,20°C, respectively. Mitochondrial cytochrome oxidase and sex-determining region of Y chromosome genes were successfully amplified from DNA extracted from the blood spots. Conclusion:, Our data indicate that TT4 and TSH are most stable in blood spots stored at ,20°C under continuous power supply. However, they can be stored at RT or at 4°C and ,20°C under interrupted power supply for at least 2.5 years. Moreover, the DNA extracted from the blood spots was intact and suitable for genetic studies. [source] Determination of total homocysteine in dried blood spots using high performance liquid chromatography for homocystinuria newborn screeningPEDIATRICS INTERNATIONAL, Issue 1 2004Andi Dwi Bahagia Febriani AbstractBackground: The most widely used method for newborn screening for homocystinuria (HCU) is a semiquantitative bacterial inhibition assay for measuring methionine concentration in dried blood spots (DBS). Because this method has resulted in a number of missed cases due to many factors, we developed a high performance liquid chromatography (HPLC) method with fluorescence detection to measure total homocysteine (tHcy) in DBS which might be useful for newborn screening for HCU. Methods: One disk of DBS 3 mm in diameter was sonicated in 10 min. The extract was reduced with dithioerythritol and was derivatized with 4-aminosulfonyl-7fluoro-2,1,3-benzoxadiazole before injection into HPLC. Results: This method showed good linearity (r = 0.996), precision (coefficient of variation range 2.7,5%), and excellent correlation coefficient between DBS and serum tHcy, both in control (r = 0.932) and patient samples (r = 0.952). By this method, the mean tHcy concentration in DBS of preterm newborns, full-term newborns, and adults was 1.4 ± 1.0, 2.5 ± 1.6, and 4.9 ± 1.5 µmol/L, respectively. The mean tHcy DBS concentration in two cases of cystathionine-,-synthase deficiency and one case of 5,10-methylentetrahydrofolate reductase deficiency was 22.7 ± 2.88, 29.3 ± 1.90, and 41.3 µmol/L, respectively. Conclusions: The present method, which is rapid, user friendly and reliable, seems applicable to newborn screening of HCU in place of methionine measurement. [source] Enzyme immunoassay for total immunoglobulin E in dried blood spotsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2007Susan Tanner Elevated circulating levels of total immunoglobulin E (IgE) are associated with both allergic disease and repeated macro-parasitic infections. Population-based research on IgE has been limited by the logistical constraints associated with obtaining and processing venipuncture blood samples. In this short report, we present an enzyme immunoassay protocol for quantifying circulating total IgE levels in capillary whole blood, collected from a finger prick and dried on filter paper. The assay demonstrated acceptable levels of accuracy, precision, and reliability. IgE remained stable at room temperature for only 2,4 days and degraded rapidly at higher temperatures suggesting that samples should be refrigerated or frozen within 1,2 days of collection. It is hoped that the relative ease of blood spot collection will expand opportunities for population-based research on IgE.Am. J. Hum. Biol. 19:440,442, 2007. © 2007 Wiley-Liss, Inc. [source] Direct tandem mass spectrometric analysis of amino acids in dried blood spots without chemical derivatization for neonatal screeningRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2003Kornél Nagy Neonatal screening performed by electrospray tandem mass spectrometry is a powerful technique in clinical diagnostics. In the present paper an alternative to the widely accepted method involving butylation has been developed. In the new method butylation is not required, and multiple reaction monitoring (MRM) was used instead of constant neutral loss scanning. The method was optimized for detection of 23 L-amino acids in their native form. Quantitation was based on isotope-labeled internal standards, calibration curves were linear from 0 to 500,,mol/L, and detection limits were in the range 2,42,,mol/L. The utility of the present technique is illustrated in the case of one neonate suffering from citrullinaemia. Copyright © 2003 John Wiley & Sons, Ltd. [source] DNA Cards: Determinants of DNA Yield and Quality in Collecting Genetic Samples for Pharmacogenetic StudiesBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2007Sergi Mas The aims of this study were two-fold: to compare the amount and quality of DNA obtained from two different DNA cards (IsoCode Cards® or FTA Classic Cards®, Whatman plc, Brentford, Middlesex, UK); and to evaluate the effects of time and storage temperature, as well as the influence of anticoagulant ethylenediaminetetraacetic acid on the DNA elution procedure. The samples were genotyped by several methods typically used in pharmacogenetic studies: multiplex PCR, PCR-restriction fragment length polymorphism, single nucleotide primer extension, and allelic discrimination assay. In addition, they were amplified by whole genome amplification to increase genomic DNA mass. Time, storage temperature and ethylenediaminetetraacetic acid had no significant effects on either DNA card. This study reveals the importance of drying blood spots prior to isolation to avoid haemoglobin interference. Moreover, our results demonstrate that re-isolation protocols could be applied to increase the amount of DNA recovered. The samples analysed were accurately genotyped with all the methods examined herein. In conclusion, our study shows that both DNA cards, IsoCode Cards® and FTA Classic Cards®, facilitate genetic and pharmacogenetic testing for routine clinical practice. [source] Evaluation of infant methylenetetrahydrofolate reductase genotype, maternal vitamin use, and risk of high versus low level spina bifida defects,BIRTH DEFECTS RESEARCH, Issue 3 2003Kelly A. Volcik BACKGROUND Several studies have suggested that homozygosity for the C677T 5,10-methylenetetrahydrofolate reductase (MTHFR) variant is a potential risk factor for neural tube defects (NTDs), as individuals homozygous for the C677T allele have slightly elevated homocysteine concentrations under conditions of low folic acid intake. It has been hypothesized that maternal folic acid supplementation prevents NTDs by partially correcting reduced MTHFR activity associated with the variant form of the enzyme. METHODS Genomic DNA was extracted from newborn screening blood spots obtained from 145 infants with spina bifida (SB) and 260 nonmalformed control infants. The MTHFR C677T genotype was determined by restriction enzyme digestion of PCR amplification products with Hinf1. We investigated whether infant MTHFR genotype influenced the risk for the anatomic level of the SB lesion (high vs. low); we also explored whether maternal vitamin use influenced this risk. RESULTS Compared to controls, the frequency of SB infants with the homozygous 677 TT genotype was greatest in those infants with high level SB defects (26%; odds ratio [OR] = 2.9; 95% confidence interval [CI] = 0.9,10.1) than for those with low level SB defects (22%; OR = 1.8; 95% CI = 0.9,3.2). Furthermore, homozygous 677TT infants whose mothers did not use vitamins containing folic acid had a modestly increased risk of SB (OR = 1.8; 95% CI = 0.8,3.9), with this risk increasing more than three-fold (OR = 5.5; 95% CI = 0.8,28.1) for those infants with high level SB defects whose mothers did not use vitamins. CONCLUSIONS Based upon our observations, it is suggested that the association between the infant MTHFR homozygous variant genotype and spina bifida risk may be conditional upon both lesion level and maternal vitamin use. Birth Defects Research (Part A) 67:154,157, 2003. © 2003 Wiley-Liss, Inc. [source] Apolipoprotein E and apolipoprotein B genotypes and risk for spina bifidaBIRTH DEFECTS RESEARCH, Issue 5 2002Kelly A. Volcik Background Altered cholesterol metabolism and defects in cholesterol biosynthesis may influence abnormal central nervous system (CNS) development. During early stages of embryonic development, high levels of cholesterol are needed by rapidly proliferating cells that utilize cholesterol as a key cell membrane component. Alterations in cholesterol levels are influenced by variations in the apolipoprotein E (apoE) and apolipoprotein B (apoB) genes. The purpose of our study was to explore the possible association between infant genetic variations in the apoE and apoB genes and spina bifida (SB) risk. Methods Genomic DNA was extracted from newborn screening blood spots obtained from 26 infants with SB and 73 non-malformed control infants. ApoE and apoB genotypes were determined by restriction enzyme digestion of PCR amplification products. Results Genotype frequencies for the apoE and apoB polymorphisms were not statistically different between case and control infants. For each apoB polymorphism, however, the frequency of the wild-type allele was higher in SB infants as compared to controls. Additionally, the apoE genotype E2/E3 was observed more frequently in the controls than in SB infants [15% in controls compared to 4% in cases; OR = 0.2 (0,1.6)]. Conclusions Results from this study suggest that genetic variations in the apoE and apoB genes, known to regulate cholesterol metabolism, do not substantially contribute to the risk of SB in infants. Teratology 66:257,259, 2002. © 2002 Wiley-Liss, Inc. [source] Infants with late breast milk acquisition of HIV-1 generate interferon-gamma responses more rapidly than infants with early peripartum acquisitionCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2009B. Lohman-Payne Summary Infants infected with HIV-1 after the first month of life have a lower viral set-point and slower disease progression than infants infected before 1 month. We investigated the kinetics of HIV-1-specific CD8+ T lymphocyte secretion of interferon (IFN)-, in infants infected before 1 month of life compared with those infected between months 1 and 12 (late infection). HIV-1 infection was assessed at birth and at months 1, 3, 6, 9 and 12 and timing of infection was determined by HIV-1 gag DNA from dried blood spots and verified by plasma HIV-1 RNA levels. HIV-1 peptide-specific IFN-, responses were measured by enzyme-linked immunospot at months 1, 3, 6, 9 and 12. Timing of development of IFN-, responses was compared using the log,rank test and Kaplan,Meier survival curves. Infants infected late developed HIV-1-specific CD8+ T cell responses 2·8 months sooner than infants infected peripartum: 2·3 versus 5·1 months after HIV-1 infection (n = 52, P = 0·04). Late-infected infants had more focused epitope recognition than early-infected infants (median 1 versus 2 peptides, P = 0·03); however, there were no differences in the strength of IFN-, responses. In infants infected with HIV-1 after the first month of life, emergence of HIV-1-specific CD8+ IFN-, responses is coincident with the decline in viral load, nearly identical to what is observed in adults and more rapid than in early-infected infants. [source] Evaluation of the Murex HIV Ag/Ab Combination assay when used with dried blood spotsCLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2007V. Lakshmi Abstract This study evaluated the ability of the Murex HIV Ag/Ab Combination assay to detect human immunodeficiency virus (HIV) antibodies in 12 617 dried blood spots (DBSs) on filter paper. The assay had an overall sensitivity of 99.6% and a specificity of 99.9%. In view of its ability to detect p24 antigen and both HIV-1 and HIV-2 antibodies in samples collected in the form of DBSs, the Murex Ag/Ab Combination assay is suitable for use as a standard screening assay for seroprevalence studies, as well as for routine diagnostic use in clinical laboratories. [source] | ||||||||||||||||