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Blood Collection (blood + collection)

Distribution by Scientific Domains

Medical Sciences	90%
2 Other Domains	10%

Distribution within Medical Sciences

Pediatrics	10%
14 Other Subdomains	80%

Selected Abstracts

Mean platelet volume in neonatal respiratory distress syndrome

PEDIATRICS INTERNATIONAL, Issue 2 2009
Fuat Emre Canpolat
Abstract The aim of this study was to investigate the differences in mean platelet volume (MPV) between neonates with and without neonatal respiratory distress syndrome (RDS). Eighty-three premature infants who were admitted to the neonatal intensive care unit were included in the study. Forty-four of these infants were diagnosed as having RDS and the other 39 infants were non-RDS patients. Infants born to mothers with pre-eclampsia, or a drug history that had negative effects on platelet count, perinatal hypoxia, sepsis and necrotizing enterocolitis were excluded. Blood collection was done on the first and third days of life. There were no demographic, gestational or platelet count differences between groups, but MPV was higher in RDS patients and this difference was statistically significant (P= 0.011). High platelet volumes in RDS patients is probably related to young platelet production and may be a result of increased platelet consumption in pulmonary damage due to RDS. [source]

Nutritional factors affecting serum phenylalanine concentration during pregnancy for identical twin mothers with phenylketonuria

ACTA PAEDIATRICA, Issue 8 2000
C Fox
The effect of energy, protein, fat, and phenylalanine on serum phenylalanine concentrations during pregnancy for a set of identical twins with phenylketonuria (PKU) was examined. Blood samples were collected one to two times per week. The subjects completed a 3-d food record prior to each blood collection. The effect of the factors on serum phenylalanine levels was evaluated statistically using time-series analysis. Dietary intakes of the nutrients evaluated were similar for the subjects. For one subject, there were highly significant effects of energy, protein, and fat on serum phenylalanine levels. In contrast, these nutrients had no significant effect on serum phenylalanine for the other subject. Dietary phenylalanine had no significant effect on serum phenylalanine for either twin. Conclusions: There was no effect of phenylalanine intake and no consistent effect of energy, protein, or fat on serum phenylalanine. Other dietary or environmental factors or a combination of factors may impact serum phenylalanine levels of pregnant women with PKU. [source]

Zinc and copper plasma levels in Icelandic horses with Culicoides hypersensitivity

EQUINE VETERINARY JOURNAL, Issue 5 2001
G. STARK
Summary Zinc concentration has been shown to have a potent immunomodulatory capacity, particularly influencing T helper cell organisation and cytokine secretion. Culicoides hypersensitivity (CHS) in horses resembles the early and late phase of type I hypersensitive reactions in man, characterised by a shift from T helper cell subtype 1 to T helper cell subtype 2 cytokine profile. In this pilot study, zinc and copper levels were measured in the plasma of 48 CHS-affected and 56 healthy Icelandic horses age 4,25 years (mean , 11 years) kept on 7 farms. Affected horses were divided into 3 groups according to the severity of disease. Time of blood collection and feeding management was constant. No differences in zinc or copper plasma levels and plasma copper/zinc ratio were determined among CHS horses and controls by univariate analysis of variance. Therefore, the most significant influences on zinc and copper plasma levels were affected by the location of housing. However, Spearman correlation showed a negative coefficient between the plasma zinc concentration and the severity of CHS (r =,0.31). Due to a probability value of P = 0.002 the null hypothesis r = 0 is rejected, although only 9% of the total variation of plasma zinc is presently explained by its relationship to CHS. In contrast, the Spearman correlation coefficient between plasma copper levels and severity of CHS was not significant (r =,0.14; P = 0.16). The minor deviations in plasma zinc concentrations in association with the severity of CHS may be real or due to neurohumoral or cytokine-mediated mechanisms, but appear too minimal to be relevant. [source]

A prospective pilot study of antibodies against human papillomaviruses and cutaneous squamous cell carcinoma nested in the Oxford component of the European Prospective Investigation into Cancer and Nutrition

INTERNATIONAL JOURNAL OF CANCER, Issue 8 2007
Delphine Casabonne
Abstract In a prospective pilot study nested in the EPIC-Oxford cohort, we examined the seroprevalence of antibodies against the L1 antigen of 38 human papilloma virus (HPV) types among 39 cases of cutaneous squamous cell carcinoma (SCC) for whom plasma was collected prior to diagnosis (incident) and 80 controls. Fifteen cases having already developed SCC at blood collection (prevalent) were also tested. There were no statistically significant differences in the seroprevalence of antibodies against any of the HPV types examined between incident cases and controls, nor was there a difference in the seroprevalence of multiple infections. However, consistent with results from published case,control studies, the seroprevalence of many ,-HPV types was higher among prevalent cases than among either incident cases or controls. For example the seroprevalence of antibodies against HPV-8 was 20% (16/80) in controls, 23% (9/39) among incident cases and 40% (6/15) among prevalent cases. Among the incident cases only, the seroprevalence was 16% (5/32) among those for whom blood was collected 18+ months prior to diagnosis, but 57% (4/7) among those for whom diagnosis was within 18 months of blood collection, a pattern seen for many of the HPV types. This might suggest that if HPV is involved in the aetiology of SCC, the process occurs close to the time of diagnosis, or that the antibody response observed in people with SCC is a consequence of tumor formation. Further and larger prospective studies are needed to clarify the role of HPV in the aetiology of cutaneous SCC. © 2007 Wiley-Liss, Inc. [source]

Circulating enterolactone and prostate cancer risk: A Nordic nested case-control study

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2002
Pär Stattin
Abstract Enterolactone, a phytoestrogen belonging to the class of lignans, is produced by the intestinal microflora from precursors in plant foods and has been implicated in protection against cancer. We study the effect of enterolactone on the risk of a subsequent diagnosis of prostate cancer. We conducted a longitudinal, nested case-control study by linkage of 3 biobanks to the cancer registries in Finland, Norway and Sweden, respectively. Enterolactone concentrations were measured by time-resolved fluoroimmunoassay in serum from 794 men who had a diagnosis of prostate cancer at a mean follow-up time of 14.2 years after blood collection and among 2,550 control men matched within each cohort for age (±2 years), date of blood collection (±2 months) and county. The median enterolactone concentrations did not differ between case and control subjects in the full study group (8.4 nmol/L [25th,75th percentile = 4.5,15.0] vs. 8.5 nmol/L [25th,75th percentile = 4.3,15.9]), nor in the national groups. Odds ratios of prostate cancer risk estimated by conditional logistic regression for increasing concentrations of enterolactone in quartiles in the full study group were 1.00 (referent), 1.21 (95% confidence interval [CI] = 0.96,1.52), 1.16 (95% CI = 0.91,1.47) and 1.08 (95% CI = 0.83,1.39). The OR estimate for the highest vs. the lowest quartile of enterolactone in separate analyses of the Norwegian, Finnish and Swedish cohort was 1.21 (95% CI = 0.91,1.60), 1.02 (95% CI = 0.59,1.76) and 0.87 (95% CI = 0.45,1.67), respectively. No support for the hypothesis that high circulating enterolactone is protective against prostate cancer was found. © 2002 Wiley-Liss, Inc. [source]

Right or wrong sample received for coagulation testing?

INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1p2 2010
Tentative algorithms for detection of an incorrect type of sample
Summary Inappropriate blood collection potentially comprises the major pre-analytical problem for coagulation testing. Inappropriate samples are most difficult to detect when received as secondary aliquots, common for referred tests. This study aimed to identify a simple, quick and inexpensive process to help laboratories distinguish the type of sample, should there be suspicion of inappropriate collection. Samples from 15 patients [selected on the basis that four different primary tubes were available: serum, citrated plasma, ethylene diamine tetraacetic acid (EDTA) plasma, lithium-heparin plasma], were tested for common electrolytes that might substantially differ according to the type of sample. In citrated plasma, potassium, chloride, calcium and magnesium were significantly decreased compared with serum and lithium-heparin plasma, while sodium was markedly increased. In EDTA plasma, sodium and chloride were significantly decreased compared with both serum and lithium-heparin plasma, potassium was always >14 mmol/l, whereas magnesium and calcium were virtually undetectable. These data allowed development of two algorithms for differential identification of citrated plasma vs. other samples with 100% sensitivity and specificity, the former based on the sequential measurement of potassium, calcium and sodium, the latter on potassium and sodium. These simple assays can supplement classical coagulation test methods to identify most inappropriate blood collections and validate sample rejection. [source]

A cornerstone for adequate supply of safe blood

ISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2006
M. Y. Zhu
Blood safety and timely adequate supply have significant impacts not only on healthcare service, but also the socio-economic development and political stability of a country. However, until a decade ago the importance has not been seriously taken in the country. Distinct blood programme and safety strategy were not always available. In certain regions of the country the supervision to establishments involved in blood collection, processing and transfusion was neither strict nor sufficient. During the early period of 1990, HIV was transmitted among plasma-apheresis donors in two central provinces. The relevant plasma-apheresis centres, in which plasma is collected solely as source materials for fractionation, were accused for wrongdoings including not performing HIV screening, and mixing red cells from different donors with same blood types before back infusion. [source]

Peripheral blood stem cell collection in pediatric patients: Feasibility of leukapheresis under anesthesia in uncompliant small children with solid tumors ,

JOURNAL OF CLINICAL APHERESIS, Issue 2 2006
Fernando Ravagnani
Leukapheresis demands patient's compliance and adequate vascular accesses, which can require invasive methods in very small children whose treatment protocol includes hemopoietic stem cell collection for myeloablative chemotherapy and stem cell rescue. Since 1998, at the Istituto Nazionale Tumori of Milan, in selected uncompliant small children, the placement of peripheral vascular accesses and leukapheresis have been performed at the same time under general anesthesia. Peripheral venous cannulas were positioned for blood collection, while blood was returned through either peripheral cannulas or mono-lumen central catheters previously installed for chemotherapy. A continuous-flow cell separator was used for leukapheresis. Between 1998 and 2003, 47 children with solid tumors underwent anesthesia for a total of 54 leukaphereses. The patients' age ranged from 12.7 to 93 months (median 30.3) and their weight ranged from 7 to 20 kg (median 14.1). Neither metabolic nor anesthesiological complications were recorded. In 89% of cases, the CD 34+ cell target was achieved at a single harvest; the median number of CD 34+ cells was 10.8 × 106/kg/leukapheresis (range 1,117) and the median collection efficiency was 63.4% (range 25,100.6). Leukapheresis under anesthesia is feasible and safe in very low-weight children whose compliance is lacking due to age and disease. J. Clin. Apheresis, 2005 © 2005 Wiley-Liss, Inc. [source]

Accuracy and reliability of continuous blood glucose monitor in post-surgical patients

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2009
K. YAMASHITA
Background: The STG-22Ô is the only continuous blood glucose monitoring system currently available. The aim of this study is to determine the accuracy and reliability of the STG-22Ô for continuously monitoring blood glucose level in post-surgical patients. Methods: Fifty patients scheduled for routine surgery were studied in surgical intensive care unit (ICU) of a university hospital. After admission to the ICU, the STG-22Ô was connected to the patients. An attending physician obtained blood samples from a radial arterial catheter. Blood glucose level was measured using the ABLÔ800FLEX immediately after blood collection at 0, 4, 8, and 16 h post-admission to the ICU (total of 200 blood glucose values). Results: The correlation coefficient (R2) was 0.96. In the Clarke error grid, 100% of the paired measurements were in the clinically acceptable zone A and B. The Bland and Altman analysis showed that bias±limits of agreement (percent error) were 0.04(0.7)±0.35(6.3) mmol (mg/dl) (7%), ,0.11(,2)±1.22(22) (15%) and ,0.33(,6)±1.28(23) (10%) in hypoglycemia (<70(3.89) mmol (mg/dl), normoglycemia (3.89(70),10(180) mmol (mg/dl), and hyperglycemia (>10(180) mmol (mg/dl), respectively. Conclusions: The STG-22Ô can be used for measuring blood glucose level continuously and measurement results are consistent with intermittent measurement (percentage error within 15%). Therefore, the STG-22Ô is a useful device for monitoring in blood glucose level in the ICU for 16 h. [source]

Prenatal Alcohol Exposure Alters Biobehavioral Reactivity to Pain in Newborns

ALCOHOLISM, Issue 4 2010
Tim F. Oberlander
Objectives:, To examine biobehavioral responses to an acute pain event in a Cape Town, South Africa, cohort consisting of 28 Cape Colored (mixed ancestry) newborns (n = 14) heavily exposed to alcohol during pregnancy (exposed), and born to abstainers (n = 14) or light (,0.5 oz absolute alcohol/d) drinkers (controls). Methods:, Mothers were recruited during the third trimester of pregnancy. Newborn data were collected on postpartum day 3 in the maternity obstetrical unit where the infant had been delivered. Heavy prenatal alcohol exposure was defined as maternal consumption of at least 14 drinks/wk or at least 1 incident of binge drinking/mo. Acute stress-related biobehavioral markers [salivary cortisol, heart rate (HR), respiratory sinus arrhythmia (RSA), spectral measures of heart rate variability (HRV), and videotaped facial actions] were collected thrice during a heel lance blood collection (baseline, lance, and recovery). After a feeding and nap, newborns were administered an abbreviated Brazelton Neonatal Behavioral Assessment Scale. Results:, There were no between-group differences in maternal age, marital status, parity, gravidity, depression, anxiety, pregnancy smoking, maternal education, or infant gestational age at birth (all ps > 0.15). In both groups, HR increased with the heel lance and decreased during the postlance period. The alcohol-exposed group had lower mean HR than controls throughout, and showed no change in RSA over time. Cortisol levels showed no change over time in controls but decreased over time in exposed infants. Although facial action analyses revealed no group differences in response to the heel lance, behavioral responses assessed on the Brazelton Neonatal Scale showed less arousal in the exposed group. Conclusions:, Both cardiac autonomic and hypothalamic,pituitary,adrenal stress reactivity measures suggest a blunted response to an acute noxious event in alcohol-exposed newborns. This is supported by results on the Brazelton Neonatal Scale indicating reduced behavioral arousal in the exposed group. To our knowledge, these data provide the first biobehavioral examination of early pain reactivity in alcohol-exposed newborns and have important implications for understanding neuro-/biobehavioral effects of prenatal alcohol exposure in the newborn period. [source]

Acute Stress Hyperglycemia in Cats Is Associated with Struggling and Increased Concentrations of Lactate and Norepinephrine

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2002
Jacqueline S. Rand
We characterized the changes in blood glucose concentrations in healthy cats exposed to a short stressor and determined the associations between glucose concentrations, behavioral indicators of stress, and blood variables implicated in stress hyperglycemia (plasma glucose, lactate, insulin, glucagon, cortisol, epinephrine, and norepinephrine concentrations). Twenty healthy adult cats with normal glucose tolerance had a 5-minute spray bath. Struggling and vocalization were the most frequent behavioral responses. There was a strong relationship between struggling and concentrations of glucose and lactate. Glucose and lactate concentrations increased rapidly and significantly in all cats in response to bathing, with peak concentrations occurring at the end of the bath (glucose baseline 83 mg/dL, mean peak 162 mg/dL; lactate baseline 6.3 mg/dL, mean peak 64.0 mg/dL). Glucose response resolved within 90 minutes in 12 of the 20 cats. Changes in mean glucose concentrations were strongly correlated with changes in mean lactate (r= .84; P <.001) and mean norepinephrine concentrations (r= .81; P < .001). There was no significant correlation between changes in mean glucose concentrations and changes in mean insulin, glucagon, cortisol, or epinephrine concentrations. Struggling and lactate concentrations were predictive of hyperglycemia. Gluconeogenesis stimulated by lactate release is the likely mechanism for hyperglycemia in healthy cats in this model of acute stress. Careful handling techniques that minimize struggling associated with blood collection may reduce the incidence of stress hyperglycemia in cats. [source]

Efficacy and safety of conversion of mycophenolate mofetil to enteric-coated mycophenolate sodium in Mexican renal transplant children

PEDIATRIC TRANSPLANTATION, Issue 6 2010
H. Reyes
Reyes H, Hernández AM, Valverde S, Cataneo A, Mendoza A, Barrera I, Ortíz L, García-Roca P, Lopéz-Martínez B, Castañeda-Hernández G, Medeiros M. Efficacy and safety of conversion of mycophenolate mofetil to enteric-coated mycophenolate sodium in Mexican renal transplant children. Pediatr Transplantation 2010: 14:746,752. © 2010 John Wiley & Sons A/S. Abstract:, The aim of the study was to evaluate the efficacy and safety of the conversion of MMF to EC-MPS in pediatric renal transplant recipients. We included 12 patients with stable graft function who were receiving MMF treatment. In the first visit, a complete medical examination was performed, which included a GSRS, a nine-point pharmacokinetic profile, samples for renal, liver and hematological tests and evaluation of IMPDH2 gene expression. The patients were transferred to an equimolar dose of EC-MPS. Two wk later, a clinical evaluation and blood collection, as in the first visit were performed. There was no change in serum creatinine, leukocyte count, serum albumin, or transaminase levels, but we found a statistically significant reduction of hemoglobin after conversion (13.2 ± 1.6 g/dL with MMF vs. 12.5 ± 1.3 g/dL when receiving EC-MPS). The GSRS total mean score was 16 ± 12 with MMF vs. 8 ± 5 with EC-MPA (p < 0.05). There was no statistically significant difference between formulations in the gene expression of IMPDH 2, in the AUC0-12h or in Cmax. However, peak concentration occurred later with EC-MPS. [source]

Cell-free fetal DNA (SRY locus) concentration in maternal plasma is directly correlated to the time elapsed from the onset of preeclampsia to the collection of blood

PRENATAL DIAGNOSIS, Issue 4 2004
Antonio Farina MD
Abstract Objective To determine (1) if fetal DNA (fDNA) in the maternal circulation in women affected by preeclampsia correlates with the time elapsed from the onset of symptoms to the time of blood collection, and (2) if the inclusion of this variable improves the discrimination between affected and unaffected patients by using fDNA distributions. Methods Plasma were collected from 34 women at 33.7 ± 3.9 weeks' gestation, affected by preeclampsia, and bearing a single male fetus. fDNA was extracted from 1.5-mL plasma samples, and the SRY and ,-globin gene were analyzed by real-time quantitative PCR. MoMs (multiple of the control median) were calculated by using a log equation of 102 normal cases. Log MoMs were then plotted against the time elapsed from onset of symptoms to blood collection (expressed in days) by means of a log-linear regression. Adjusted MoMs were then calculated. ROC curves were used to test the discrimination obtained by using adjusted MoMs. Results The median MoMs of controls and preeclamptic patients were 1.00 ± 1.53 and 2.62 ± 2.70 respectively. By plotting log MoM fDNA against the time elapsed from onset of symptoms to blood collection, we found a significant positive correlation, (p -value < 0.001, R2 = 0.55, F = 38.97, from 1 to 50 days). The adjusted median fDNA MoM was 2.66 ± 2.50. Areas under the curves, as estimated by ROC curves, were 76.7 for unadjusted and 85.5 for adjusted MoMs respectively (p -value = 0.02). Conclusions The effect of a further covariate showed that (1) fDNA passage from trophoblasts to maternal circulation for unit of time is proportional to the duration of the damage and that (2) increased discrimination can be obtained in comparison to normal subjects. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Higher 25-hydroxyvitamin D is associated with lower relapse risk in multiple sclerosis,

ANNALS OF NEUROLOGY, Issue 2 2010
Steve Simpson Jr. MPH
Objective A protective association between higher vitamin D levels and the onset of multiple sclerosis (MS) has been demonstrated; however, its role in modulating MS clinical course has been little studied. We investigated whether higher levels of serum 25-hydroxyvitamin D (25-OH-D) were associated with a lower risk of relapses in people with MS. Methods We conducted a prospective cohort study of 145 participants with relapsing-remitting MS from 2002 to 2005. Serum 25-OH-D levels were measured biannually, and the hazard of relapse was assessed using survival analysis. Results There was an inverse linear relationship between 25-OH-D levels and the hazard of relapse over the subsequent 6 months, with hazard ratio (HR) 0.91 (95% confidence interval [CI]: 0.85,0.97) per 10nmol/l increase in 25-OH-D level (p = 0.006). When variation due to timing of blood collection was removed by estimating 25-OH-D at the start of each season, this association persisted, with HR 0.90 (95% CI, 0.83,0.98) per 10nmol/l increase (p = 0.016). Taking into account the biological half-life of 25-OH-D, we estimated 25-OH-D at monthly intervals, resulting in a slightly enhanced association, with HR 0.88 (95% CI, 0.82,0.95) per 10nmol/l increase (p = 0.001). Adjusting for potential confounders did not alter these findings. Interpretation In this prospective population-based cohort study, in a cohort largely on immunomodulatory therapy, higher 25-OH-D levels were associated with a reduced hazard of relapse. This occurred in a dose-dependent linear fashion, with each 10nmol/l increase in 25-OH-D resulting in up to a 12% reduction in risk of relapse. Clinically, raising 25-OH-D levels by 50nmol/l could halve the hazard of a relapse. ANN NEUROL 2010;68:193,203 [source]

Biomarkers of inflammation and development of rheumatoid arthritis in women from two prospective cohort studies

ARTHRITIS & RHEUMATISM, Issue 3 2009
Elizabeth W. Karlson
Objective To examine the association of biomarkers of inflammation with preclinical rheumatoid arthritis (RA). Methods A nested case,control study was performed using samples from 2 large, prospectively studied cohorts of women (the Women's Health Study [WHS] and the Nurses' Health Study [NHS]). Blood samples obtained prior to symptom onset in women who later developed RA were selected as incident RA cases, and 3 controls per case were randomly chosen, matched for age, menopausal status, postmenopausal hormone use, and day, time, and fasting status at the time of collection. Plasma was tested for levels of interleukin-6 (IL-6), soluble tumor necrosis factor receptor II (sTNFRII) (as a proxy for TNF,), and high-sensitivity C-reactive protein. Relationships between biomarkers and RA were assessed using conditional logistic regression models, adjusting for age, body mass index, smoking habits, ethnicity, and reproductive factors. Results In 93 incident cases in the NHS and 77 incident cases in the WHS, the mean time between blood collection and the onset of RA symptoms was 5.2 years (range 0.3,12 years). Median IL-6 and sTNFRII levels were significantly higher in preclinical RA cases compared with matched controls in the NHS (P = 0.03 and P = 0.003, respectively) though not in the WHS. Pooled analysis of the NHS and WHS cohorts demonstrated significant association of sTNFRII with RA (relative risk 2.0 [95% confidence interval 1.1,3.6], P for trend = 0.004), and a modest association of IL-6 with RA (relative risk 1.4 [95% confidence interval 0.8,2.5], P for trend = 0.06). Conclusion Levels of sTNFRII, a biomarker typically associated with active RA, were elevated up to 12 years prior to the development of RA symptoms and were positively associated with incident RA in these nested case,control studies. Studies with repeated assessments of biomarkers prior to RA development may provide further insight into the timing of biomarker elevation in preclinical RA. [source]

Clinical Pathology Alterations in Pregnant and Non-Pregnant Rats following Scorpion Envenomation

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2009
Hmed Ben Nasr
Existing diagnostic criteria are not sufficiently specific to allow antivenin administration in the absence of a confirmed scorpion sting. This study was performed to evaluate conventional haematological and serum chemical measurements as potential indices of scorpion envenomation. Adult, cycling nulliparous and near-term primiparous, white Wistar rats received a single subcutaneous injection of crude venom (600 µg/kg) from the Buthidae scorpion (Buthus occitanus tunetanus). All envenomed rats were observed for external signs and symptoms of toxicity until necropsy, which entailed terminal blood collection at either 0.5, 1, 2, or 4 hr after venom administration (n = 6 per reproductive state per time-point) for evaluation of selected clinical chemistry and haematological analytes. Control cohorts (matched for age and reproductive state) received saline injections subcutaneously and were necropsied at 0.5 hr. Almost all envenomed rats but no control animals displayed physical symptoms of intoxication, including agitation, mastication with hypersalivation, and/or vocalizing. Reproducible alterations in clinical pathology parameters were lacking in venom-treated rats regardless of reproductive status, although modest but significant Rho correlations suggested that mild haemoconcentration, haemolysis, renal function deficits and possibly coagulation difficulties developed over time. [source]

Dried blood spot sampling in combination with LC-MS/MS for quantitative analysis of small molecules

BIOMEDICAL CHROMATOGRAPHY, Issue 1 2010
Wenkui 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 limited sampling strategy for tacrolimus in renal transplant patients

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 4 2008
Binu S. Mathew
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT , Tacrolimus trough concentration is being currently used for dose individualization. , Limited sampling strategies (LSS) have been developed and validated for renal transplant patients. , Earlier literature has suggested that measurement of tacrolimus AUC is more reliable than trough with respect to both rejection and nephrotoxicity. WHAT THIS STUDY ADDS , Four thousand renal transplants take place annually in India, with many patients prescribed tacrolimus in combination with mycophenolate and steroid. , In this study a LSS with two points, i.e. trough and 1.5 h postdose was developed and validated to estimate AUC0,12. , The added benefit of only a single additional sample with completion of blood collection in 1.5 h and minimum additional cost makes this a viable LSS algorithm in renal transplant patients. , In patients having tacrolimus trough concentrations outside the recommended range (<3 and >10 ng ml,1 in the treatment protocol in our institution) or having side-effects in spite of trough concentrations in the desired range, we can estimate AUC using this LSS for a better prediction of exposure. AIMS To develop and validate limited sampling strategy (LSS) equations to estimate area under the curve (AUC0,12) in renal transplant patients. METHODS Twenty-nine renal transplant patients (3,6 months post transplant) who were at steady state with respect to tacrolimus kinetics were included in this study. The blood samples starting with the predose (trough) and collected at fixed time points for 12 h were analysed by microparticle enzyme immunoassay. Linear regression analysis estimated the correlations of tacrolimus concentrations at different sampling time points with the total measured AUC0,12. By applying multiple stepwise linear regression analysis, LSS equations with acceptable correlation coefficients (R2), bias and precision were identified. The predictive performance of these models was validated by the jackknife technique. RESULTS Three models were identified, all with R2 , 0.907. Two point models included one with trough (C0) and 1.5 h postdose (C1.5), another with trough and 4 h postdose. Increasing the number of sampling time points to more than two increased R2 marginally (0.951 to 0.990). After jackknife validation, the two sampling time point (trough and 1.5 h postdose) model accurately predicted AUC0,12. Regression coefficient R2 = 0.951, intraclass correlation = 0.976, bias [95% confidence interval (CI)] 0.53% (,2.63, 3.69) and precision (95% CI) 6.35% (4.36, 8.35). CONCLUSION The two-point LSS equation [AUC0,12 = 19.16 + (6.75.C0) + (3.33.C1.5)] can be used as a predictable and accurate measure of AUC0,12 in stable renal transplant patients prescribed prednisolone and mycophenolate. [source]

Plasma levels of opioid peptides after sunbed exposures

BRITISH JOURNAL OF DERMATOLOGY, Issue 6 2002
T. Gambichler
Summary Background Previous studies have indicated that solar and artificial ultraviolet (UV) radiation have a positive influence on psychological variables such as mood and emotional state. Circulating opioid peptides have been suggested as being important in this effect. Objectives To investigate in a controlled trial the influence of UVA radiation on opioid peptide levels. Methods We determined plasma levels of ,-endorphin immunoreactive material (IRM) and met-enkephalin in UV-exposed ( n = 35) and non-exposed ( n = 9) healthy volunteers. On the first day of the study, blood samples were taken from the volunteers (time A). UVA irradiation was subsequently administered with an air-conditioned tanning device. During the UV exposures the volunteers wore opaque goggles. Twenty minutes after UV exposure, blood samples were collected again (time B). Within the following 3 weeks the volunteers had a series of five UV exposures. On the last day of the study (24 h after the sixth UV exposure) blood samples were collected (time C). The cumulative UVA doses were 96 J cm ,2 for skin type II and 126 J cm ,2 for skin type III. The controls had no UV exposures. Plasma ,-endorphin IRM and met-enkephalin levels were determined using radioimmunoassays. Results At all times of blood collection (A, B, C), there were no significant differences in plasma levels of ,-endorphin IRM and met-enkephalin between UV-exposed and non-exposed volunteers ( P > 0·05). Conclusions UVA irradiation does not significantly elevate plasma levels of ,-endorphin IRM and met-enkephalin. Therefore we suggest that psychological benefits claimed to occur after UV exposure are unlikely to be mediated by the types of circulating opioid peptides measured in this study. [source]

Factors associated with elevated serum concentrations of anti-TPO antibodies in subjects with and without diffuse goitre.

CLINICAL ENDOCRINOLOGY, Issue 6 2007
American Cohort Study of Thyroid Cancer, Other Thyroid Diseases Following the Chornobyl Accident, Results from the Ukrainian
Summary Objectives, To examine factors associated with the prevalence of elevated anti-thyroid peroxidase antibodies (ATPO) among iodine-deficient adolescents and young adults and test whether associations vary according to the presence of diffuse goitre. Design, Subjects were members of the Ukrainian,American Cohort Study exposed to the Chornobyl accident whose 131I thyroid dose estimates were below 0·2 Gy. Measurements, The odds ratios (ORs) for ATPO above 60 U/ml were estimated using logistic regression models for a number of factors in the total population (N = 5133), and separately for thyroid disease-free subjects (N = 3875), those with diffuse goitre (N = 921), and diffuse goitre without autoimmune thyroiditis (AIT; N = 883). Results, Elevated ATPO was found in 9·9% of the total population and ORs were significantly higher in females, older individuals, those examined in earlier calendar years, residents of Kyiv and Chernihiv oblasts, subjects with a family history of thyroid disease, higher thyroid ultrasound volume, suppressed or elevated TSH, blood collection in March to May, very low thyroglobulin (Tg), and shorter serum storage time. When thyroid disease-free subjects and those with diffuse goitre were compared, there were few differences in antibody prevalence, and after excluding individuals with AIT, the only difference was an increased prevalence of elevated ATPO at low urinary iodine in those with goitre alone. Conclusions, Although a number of factors are associated with the prevalence of elevated ATPO in our study group, with the exception of urinary iodine these factors are independent of goitre, and differences between thyroid disease-free subjects and those with diffuse goitre are largely due to AIT. [source]