In vitro combination of human and bovine free secretory component with IgA of various species.

The free form of the secretory component usually associated with secretory IgA can be isolated from human and bovine milk. These free secretory components of different origin combine in vitro with human polymeric myeloma IgA, with mouse myeloma IgA, and with the serum IgA of nine different mammalian species.

Prediction of free imatinib concentrations based on total plasma concentrations in patients with gastrointestinal stromal tumours.

AIM: Total imatinib concentrations are currently measured for the therapeutic drug monitoring of imatinib, whereas only free drug equilibrates with cells for pharmacological action. Due to technical and cost limitations, routine measurement of free concentrations is generally not performed. In this study, free and total imatinib concentrations were measured to establish a model allowing the confident prediction of imatinib free concentrations based on total concentrations and plasma proteins measurements. METHODS: One hundred and fifty total and free plasma concentrations of imatinib were measured in 49 patients with gastrointestinal stromal tumours. A population pharmacokinetic model was built up to characterize mean total and free concentrations with inter-patient and intrapatient variability, while taking into account α1 -acid glycoprotein (AGP) and human serum albumin (HSA) concentrations, in addition to other demographic and environmental covariates. RESULTS: A one compartment model with first order absorption was used to characterize total and free imatinib concentrations. Only AGP influenced imatinib total clearance. Imatinib free concentrations were best predicted using a non-linear binding model to AGP, with a dissociation constant Kd of 319 ng ml(-1) , assuming a 1:1 molar binding ratio. The addition of HSA in the equation did not improve the prediction of imatinib unbound concentrations. CONCLUSION: Although free concentration monitoring is probably more appropriate than total concentrations, it requires an additional ultrafiltration step and sensitive analytical technology, not always available in clinical laboratories. The model proposed might represent a convenient approach to estimate imatinib free concentrations. However, therapeutic ranges for free imatinib concentrations remain to be established before it enters into routine practice.

Laser scanning evaluation of atrophy after autologous free muscle transfer.

Denervated muscle tissue undergoes morphologic changes that result in atrophy. The amount of muscle atrophy after denervation following free muscle transfer has not been measured so far. Therefore, the amount of muscle atrophy in human free muscle transfer for lower extremity reconstruction was measured in a series of 10 patients. Three-dimensional laser surface scanning was used to measure flap volume changes 2 weeks as well as 6 and 12 months after the operation. None of the muscles transferred was re-innervated.All muscles healed uneventfully without signs of compromised perfusion resulting in partial flap loss. The muscle volume decreased to 30 ± 4% and 19 ± 4% 6 and 12 months, respectively, after the operation, ie, the volume decreased by approximately 80% within a 12-month period.Denervated free muscle flap tissue undergoes massive atrophy of approximately 80%, mostly within the first 6 months.

Analytical interference of 4-hydroxy-3-methoxymethamphetamine with the measurement of plasma free normetanephrine by ultra-high pressure liquid chromatography-tandem mass spectrometry.

OBJECTIVES: The diagnosis of pheochromocytoma relies on the measurement of plasma free metanephrines assay whose reliability has been considerably improved by ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Here we report an analytical interference occurring between 4-hydroxy-3-methoxymethamphetamine (HMMA), a metabolite of 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy"), and normetanephrine (NMN) since they share a common pharmacophore resulting in the same product ion after fragmentation. DESIGN AND METHODS: Synthetic HMMA was spiked into plasma samples containing various concentrations of NMN and the intensity of the interference was determined by UPLC-MS/MS before and after improvement of the analytical method. RESULTS: Using a careful adjustment of chromatographic conditions including the change of the UPLC analytical column, we were able to distinguish both compounds. HMMA interference for NMN determination should be seriously considered since MDMA activates the sympathetic nervous system and if confounded with NMN may lead to false-positive tests when performing a differential diagnostic of pheochromocytoma.

Free and total plasma levels of lopinavir during pregnancy, at delivery and postpartum: implications for dosage adjustments in pregnant women.

BACKGROUND: Physiological changes associated with pregnancy may alter antiretroviral plasma concentrations and might jeopardize prevention of mother-to-child HIV transmission. Lopinavir is one of the protease inhibitors more frequently prescribed during pregnancy in Europe. We described the free and total pharmacokinetics of lopinavir in HIV-infected pregnant and non-pregnant women, and evaluated whether significant alterations in its disposition and protein binding warrant systematic dosage adjustment. METHODS: Plasma samples were collected at first, second and third trimester of pregnancy, at delivery, in umbilical cord and postpartum. Lopinavir free and total plasma concentrations were measured by HPLC-MS/MS. Bayesian calculations were used to extrapolate total concentrations to trough (Cmin). RESULTS: A total of 42 HIV-positive pregnant women and 37 non-pregnant women on lopinavir/ritonavir were included in the study. Compared to postpartum and control values, total lopinavir Cmin was decreased moderately (31-39%) during pregnancy, and free Cmin minimally, showing significant alteration only at delivery (-35%). However, total and free Cmin remained in all patients above the target concentrations for wild-type virus of 1,000 ng/ml, and above the unbound IC50(WT) of 0.64-0.77 ng/ml of lopinavir, respectively. Lopinavir free fractions remained higher during pregnancy compared to postpartum and controls, and were influenced by α-1-acid-glycoprotein and albumin decrease. Free cord-to-mother ratio (0.43) was 2.7-fold higher than total cord-to-mother ratio (0.16), suggesting higher fetal exposure. CONCLUSIONS: The moderate decrease of total lopinavir concentrations during pregnancy is not associated with proportional decrease in free concentrations. Both reach a nadir at delivery, albeit not to an extent that would put treatment-naive women at risk of insufficient exposure to the free, pharmacologically active concentrations of lopinavir. No dosage adjustment is therefore needed during pregnancy as it is unlikely to further enhance treatment efficacy but could potentially increase the risk of maternal and fetal toxicity. Nonetheless, in case of viral resistance in treatment-experienced pregnant women, loss of virological control or questionable adherence, it is justified to consider lopinavir dosage adjustment based on total plasma concentration measurement.

Permanent correction of an inherited ectodermal dysplasia with recombinant EDA.

X-linked hypohidrotic ectodermal dysplasia (XLHED; OMIM 305100) is a genetic disorder characterized by absence or deficient function of hair, teeth and sweat glands. Affected children may experience life-threatening high fever resulting from reduced ability to sweat. Mice with the Tabby phenotype share many symptoms with human XLHED patients because both phenotypes are caused by mutations of the syntenic ectodysplasin A gene (Eda) on the X chromosome. Two main splice variants of Eda, encoding EDA1 and EDA2, engage the tumor necrosis factor (TNF) family receptors EDAR and XEDAR, respectively. The EDA1 protein, acting through EDAR, is essential for proper formation of skin appendages; the functions of EDA2 and XEDAR are not known. EDA1 must be proteolytically processed to a soluble form to be active. Here, we show that treatment of pregnant Tabby mice with a recombinant form of EDA1, engineered to cross the placental barrier, permanently rescues the Tabby phenotype in the offspring. Notably, sweat glands can also be induced by EDA1 after birth. This is the first example of a developmental genetic defect that can be permanently corrected by short-term treatment with a recombinant protein.

Comparison of 3D segmented gradient-echo and steady-state free precession coronary MRI sequences in patients with coronary artery disease.

OBJECTIVE: Our objective was to compare two state-of-the-art coronary MRI (CMRI) sequences with regard to image quality and diagnostic accuracy for the detection of coronary artery disease (CAD). SUBJECTS AND METHODS: Twenty patients with known CAD were examined with a navigator-gated and corrected free-breathing 3D segmented gradient-echo (turbo field-echo) CMRI sequence and a steady-state free precession sequence (balanced turbo field-echo). CMRI was performed in a transverse plane for the left coronary artery and a double-oblique plane for the right coronary artery system. Subjective image quality (1- to 4-point scale, with 1 indicating excellent quality) and objective image quality parameters were independently determined for both sequences. Sensitivity, specificity, and accuracy for the detection of significant (> or = 50% diameter) coronary artery stenoses were determined as defined in invasive catheter X-ray coronary angiography. RESULTS: Subjective image quality was superior for the balanced turbo field-echo approach (1.8 +/- 0.9 vs 2.3 +/- 1.0 for turbo field-echo; p < 0.001). Vessel sharpness, signal-to-noise ratio, and contrast-to-noise ratio were all superior for the balanced turbo field-echo approach (p < 0.01 for signal-to-noise ratio and contrast-to-noise ratio). Of the 103 segments, 18% of turbo field-echo segments and 9% of balanced turbo field-echo segments had to be excluded from disease evaluation because of insufficient image quality. Sensitivity, specificity, and accuracy for the detection of significant coronary artery stenoses in the evaluated segments were 92%, 67%, 85%, respectively, for turbo field-echo and 82%, 82%, 81%, respectively, for balanced turbo field-echo. CONCLUSION: Balanced turbo field-echo offers improved image quality with significantly fewer nondiagnostic segments when compared with turbo field-echo. For the detection of CAD, both sequences showed comparable accuracy for the visualized segments.

Cadmium-free quantum dots in aqueous solution: potential for fingermark detection, synthesis and an application to the detection of fingermarks in blood on non-porous surfaces

The use of quantum dots (QDs) in the area of fingermark detection is currently receiving a lot of attention in the forensic literature. Most of the research efforts have been devoted to cadmium telluride (CdTe) quantum dots often applied as powders to the surfaces of interests. Both the use of cadmium and the nano size of these particles raise important issues in terms of health and safety. This paper proposes to replace CdTe QDs by zinc sulphide QDs doped with copper (ZnS:Cu) to address these issues. Zinc sulphide-copper doped QDs were successfully synthesized, characterized in terms of size and optical properties and optimized to be applied for the detection of impressions left in blood, where CdTe QDs proved to be efficient. Effectiveness of detection was assessed in comparison with CdTe QDs and Acid Yellow 7 (AY7, an effective blood reagent), using two series of depletive blood fingermarks from four donors prepared on four non-porous substrates, i.e. glass, transparent polypropylene, black polyethylene and aluminium foil. The marks were cut in half and processed separately with both reagents, leading to two comparison series (ZnS:Cu vs. CdTe, and ZnS:Cu vs. AY7). ZnS:Cu proved to be better than AY7 and at least as efficient as CdTe on most substrates. Consequently, copper-doped ZnS QDs constitute a valid substitute for cadmium-based QDs to detect blood marks on non-porous substrates and offer a safer alternative for routine use.

Sedentarism affects body fat mass index and fat-free mass index in adults aged 18 to 98 years.

OBJECTIVE: Body mass index does not discriminate body fat from fat-free mass or determine changes in these parameters with physical activity and aging. Body fat mass index (BFMI) and fat-free mass index (FFMI) permit comparisons of subjects with different heights. This study evaluated differences in body mass index, BFMI, and FFMI in physically active and sedentary subjects younger and older than 60 y and determined the association between physical activity, age, and body composition parameters in a healthy white population between ages 18 and 98 y. METHODS: Body fat and fat-free mass were determined in healthy white men (n = 3549) and women (n = 3184), between ages 18 and 98 y, by bioelectrical impedance analysis. BFMI and FFMI (kg/m2) were calculated. Physical activity was defined as at least 3 h/wk of endurance-type activity for at least 2 mo. RESULTS: Physically active as opposed to sedentary subjects were more likely to have a low BFMI (men: odds ratio [OR], 1.4; confidence interval [CI], 0.7-2.5; women: OR 1.9, CI 1.6-2.2) and less likely to have very high BFMI (men: OR, 0.2; CI, 0.1-0.2; women: OR, 0.1; CI, 0.02-0.2), low FFMI (men: OR, 0.5; CI, 0.3-0.9; women: OR, 0.7; CI, 0.6-0.9), or very high FFMI (men: OR, 0.6; CI, 0.4-0.8; women: OR, 0.7; CI, 0.5-1.0). Compared with subjects younger than 60 y, those older than 60 y were more like to have very high BFMI (men: OR, 6.5; CI, 4.5-9.3; women: OR, 14.0; CI, 9.6-20.5), and women 60 y and older were less likely to have a low BFMI (OR, 0.4; CI, 0.2-0.5). CONCLUSIONS: A clear association was found between low physical activity or age and height-normalized body composition parameters (BFMI and FFMI) derived from bioelectrical impedance analysis. Physically active subjects were more likely to have high or very high or low FFMI. Older subjects had higher body weights and BFMI.

Reference values of fat-free and fat masses by bioelectrical impedance analysis in 3393 healthy subjects.

Determination of fat-free mass (FFM) and fat mass (FM) is of considerable interest in the evaluation of nutritional status. In recent years, bioelectrical impedance analysis (BIA) has emerged as a simple, reproducible method used for the evaluation of FFM and FM, but the lack of reference values reduces its utility to evaluate nutritional status. The aim of this study was to determine reference values for FFM, FM, and %FM by BIA in a white population of healthy subjects, to observe the changes in these values with age, and to develop percentile distributions for these parameters. Whole-body resistance of 1838 healthy white men and 1555 women, aged 15-64 y, was determined by using four skin electrodes on the right hand and foot. FFM and FM were calculated according to formulas validated for the subject groups and analyzed for age decades. This is the first study to present BIA-determined age- and sex-specific percentiles for FFM, FM, and %FM for healthy subjects, aged 15-64 y. Mean FM and %FM increased progressively in men and after age 45 y in women. The results suggest that any weight gain noted with age is due to a gain in FM. In conclusion, the data presented as percentiles can serve as reference to evaluate the normality of body composition of healthy and ill subject groups at a given age.

Binding free energy differences in a TCR-peptide-MHC complex induced by a peptide mutation: a simulation analysis.

Recognition by the T-cell receptor (TCR) of immunogenic peptides presented by class I major histocompatibility complexes (MHCs) is the determining event in the specific cellular immune response against virus-infected cells or tumor cells. It is of great interest, therefore, to elucidate the molecular principles upon which the selectivity of a TCR is based. These principles can in turn be used to design therapeutic approaches, such as peptide-based immunotherapies of cancer. In this study, free energy simulation methods are used to analyze the binding free energy difference of a particular TCR (A6) for a wild-type peptide (Tax) and a mutant peptide (Tax P6A), both presented in HLA A2. The computed free energy difference is 2.9 kcal/mol, in good agreement with the experimental value. This makes possible the use of the simulation results for obtaining an understanding of the origin of the free energy difference which was not available from the experimental results. A free energy component analysis makes possible the decomposition of the free energy difference between the binding of the wild-type and mutant peptide into its components. Of particular interest is the fact that better solvation of the mutant peptide when bound to the MHC molecule is an important contribution to the greater affinity of the TCR for the latter. The results make possible identification of the residues of the TCR which are important for the selectivity. This provides an understanding of the molecular principles that govern the recognition. The possibility of using free energy simulations in designing peptide derivatives for cancer immunotherapy is briefly discussed.

Pediatric reference intervals for plasma free and total metanephrines established with a parametric approach: Relevance to the diagnosis of neuroblastoma.

BACKGROUND: Urine catecholamines, vanillylmandelic, and homovanillic acid are recognized biomarkers for the diagnosis and follow-up of neuroblastoma. Plasma free (f) and total (t) normetanephrine (NMN), metanephrine (MN) and methoxytyramine (MT) could represent a convenient alternative to those urine markers. The primary objective of this study was to establish pediatric centile charts for plasma metanephrines. Secondarily, we explored their diagnostic performance in 10 patients with neuroblastoma. PROCEDURE: We recruited 191 children (69 females) free of neuroendocrine disease to establish reference intervals for plasma metanephrines, reported as centile curves for a given age and sex based on a parametric method using fractional polynomials models. Urine markers and plasma metanephrines were measured in 10 children with neuroblastoma at diagnosis. Plasma total metanephrines were measured by HPLC with coulometric detection and plasma free metanephrines by tandem LC-MS. RESULTS: We observed a significant age-dependence for tNMN, fNMN, and fMN, and a gender and age-dependence for tMN, fNMN, and fMN. Free MT was below the lower limit of quantification in 94% of the children. All patients with neuroblastoma at diagnosis were above the 97.5th percentile for tMT, tNMN, fNMN, and fMT, whereas their fMN and tMN were mostly within the normal range. As expected, urine assays were inconstantly predictive of the disease. CONCLUSIONS: A continuous model incorporating all data for a given analyte represents an appealing alternative to arbitrary partitioning of reference intervals across age categories. Plasma metanephrines are promising biomarkers for neuroblastoma, and their performances need to be confirmed in a prospective study on a large cohort of patients. Pediatr Blood Cancer 2015;62:587-593. © 2015 Wiley Periodicals, Inc.

Correction chirurgicale de la tétralogie de Fallot étude comparative de deux méthodes

La survie actuelle après correction chirurgicale de la Tétralogie de Fallot (TDF) est de 97% à 12 ans. Les principaux risques à long terme sont une régurgitation pulmonaire ou une sténose récidivante de la sortie droite du coeur, une tachycardie ventriculaire pouvant entrainer une mort subite. Le but de cette étude rétrospective est de comparer la correction chirurgicale de la TDF avec patch pulmonaire versus un conduit valvé xénogreffe. Le collectif se compose de 127 patients entre 2 mois et 16 ans, opérés pour une TDF entre l'année 2000 et 2010. La correction chirurgicale était soit avec un patch, soit avec un conduit valvé à la sortie droite. Cette étude montre d'une part qu'il n'y a pas de différence de survie à un mois entre les deux méthodes opératoires. De plus, elle montre que, lors de la pose d'un patch, il y a plus de sept fois plus d'insuffisances valvulaires modérées à sévères après un mois que lors de la pose d'un conduit valvé. D'autre part, elle démontre que la différence de gradient résiduel à la sortie droite entre la correction avec patch ou conduit n'est pas significative et que la valeur du gradient résiduel à la sortie droite en postopératoire n'est pas représentative du gradient résiduel à un mois. De plus, cette étude prouve que les coronaires aberrantes ainsi qu'un shunt palliatif de Blalock-Taussig sont des facteurs de risque indépendants pour une correction avec un conduit valvé.