Microparticle-enhanced nephelometric immunoassay (Nephelia) for immunoglobulins G, A, and M

Covalent binding of gamma chains of IgG, whole IgA, and mu chains of IgM on polyfunctional hydrophilic microspheres (MS) yields MS-Ig conjugates, usable as reagents in new microparticle-enhanced nephelometric immunoassays (Nephelia). The principle of the assays is inhibition by free analyte (IgG, IgA, and IgM) of agglutination of the MS-Ig conjugate with specific antiserum, the light scattered by the aggregates being measured with a nephelometer. The immunoglobulin assays developed are easy to perform (single-step assays, no washing or phase separation) and sensitive (high dilution of biological samples to exclude interferences and pretreatment). Analytical recovery results (95.4-101.2%) and correlations with generally used commercial assays (r = 0.86-0.98) indicate that the assays are accurate for large concentration ranges of immunoglobulins. Precision sxtudy gives CVs = 2.8-9.6%. Nephelia appears to be useful for quantifying a large variety of biological molecules.

Thyroid endocrine status of wild European eels (Anguilla anguilla) in the Loire (France). Relationships with organic contaminant body burdens

In teleost fish, thyroid function is involved in various critical physiological processes. Given the complexity of the hypothalamo-pituitary-thyroid (HPT) axis, a large number of genes and proteins can be the potential target of endocrine-disrupting compounds (EDCs). The aim of this study was to evaluate, in yellow and silver European eels (Anguilla anguilla), potential effects of EDCs on thyroid status by analyzing the associations between EDC body burdens and thyroid hormones (THs). In yellow individuals, greater free T3/T4 ratios (FT3/FT4) and lower plasma FT4 levels were associated with greater concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), as highlighted by significant correlations with many congeners. Few positive relationships with alkylphenols were noticed. In contrast, silver eels usually exhibited less significant correlations between THs and contaminant loads. Expression of a series of genes involved in the HPT axis was also investigated in the silver individuals. Concerning mRNA expression in silver females, some main correlations were noticed: thyroid-stimulating hormone (TSHβ) gene expression was significantly correlated to numerous PCBs, and hepatic mRNA levels of deiodinase 2 (Deio 2) were negatively correlated to 2-hydroxyfluorene (2-OHF) and 2-naphtol (2-OHNa). Thyroid receptor (TRα and TRβ) mRNA levels exhibited weak negative correlations with some PBDEs in silver females and males. Hepatic vitellogenin (Vtg) mRNA levels were detected in all silver males but at lower levels than in silver females. In males, Vtg mRNA levels were positively associated to FT4/TT4. In silver females, strong positive correlations were found between congeners of PCBs, PBDEs and PFAS suggesting potential estrogenic effects. Overall, the observed results indicate that several organic contaminants, mainly dl-, ndl-PCBs and PBDEs, could be associated with changes in thyroid homeostasis in these fish, via direct or indirect interactions with peripheral deiodination, metabolism of T4 and mechanisms involved in TSHβ, Deio 2 and Vtg gene transcription.

Measurement of the [Formula: see text] production cross-section in proton-proton collisions via the decay [Formula: see text]

The production of the [Formula: see text] state in proton-proton collisions is probed via its decay to the [Formula: see text] final state with the LHCb detector, in the rapidity range [Formula: see text] and in the meson transverse-momentum range [Formula: see text]. The cross-section for prompt production of [Formula: see text] mesons relative to the prompt [Formula: see text] cross-section is measured, for the first time, to be [Formula: see text] at a centre-of-mass energy [Formula: see text] using data corresponding to an integrated luminosity of 0.7 fb[Formula: see text], and [Formula: see text] at [Formula: see text] using 2.0 fb[Formula: see text]. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the [Formula: see text] and [Formula: see text] decays to the [Formula: see text] final state. In addition, the inclusive branching fraction of [Formula: see text]-hadron decays into [Formula: see text] mesons is measured, for the first time, to be [Formula: see text], where the third uncertainty includes also the uncertainty on the [Formula: see text] inclusive branching fraction from [Formula: see text]-hadron decays. The difference between the [Formula: see text] and [Formula: see text] meson masses is determined to be [Formula: see text].

Search for long-lived particles decaying to jet pairs

A search is presented for long-lived particles with a mass between 25 and 50 [Formula: see text] and a lifetime between 1 and 200[Formula: see text] in a sample of proton-proton collisions at a centre-of-mass energy of [Formula: see text] TeV, corresponding to an integrated luminosity of 0.62 [Formula: see text], collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a standard model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime.

Relationships between genotypes and phenotypes in natural populations of the European flounder (Platichthys flesus) under different types of contamination in estuaries

Not available

The attitude of Flemish paediatricians regarding informed consent of adolescents

BACKGROUND

Since 2002 the Belgian law requires an informed consent of the patient before each medical intervention. This provision applies also for adolescent patients on condition that the physician considers the young patient as competent to autonomously participate in the decision making process.

AIM

The purpose of this study is to evaluate to what extent Belgian paediatricians from the Flemish part of the country have implemented the legal requirements for informed consent of adolescent patients, in particular when they consult alone.

METHODS

In the frame of a larger study regarding the relation between paediatricians and their patients, a questionnaire was sent via regular mail to 570 Flemish paediatricians, evaluating how and how often they obtain an informed consent of the adolescent when consulting a physician unaccompanied.

RESULTS

In only 1% of all consultations an adolescent consulted the physician alone and agreed to a medical intervention on his/her own. The information given by the paediatrician did not differ if the adolescent consulted alone or was accompanied by (one of) his/her parents for the following items: purpose and type of treatment (100% vs 100%), duration of treatment (92% vs 94%) and aftercare (89% vs 93%). However, the information differed with regard to alternatives to the treatment (65% vs 76%), degree of urgency (89% vs 95% ), treatment related risks (82% vs 90%) and cost (21% vs 45%). 18.6% of the paediatricians consider age as the single criterion to evaluate the competence of the adolescent to provide an informed consent; other criteria that are considered: experience (92%), insight into and factual understanding of the clinical picture (84%). To fulfil the tasks of providing information and asking for consent, paediatricians rarely had recourse to prior established protocols (14%), they preferred to rely on proper experience and expertise (81%). Fifty percent appealed to the opinion of other health care providers.

CONCLUSIONS

Although the Belgian law stipulates regulations that should be complied with by the physician during the decision making process about any medical intervention on adolescents, this legislation has rarely been put into practice, as the adolescents used their right to autonomously consent in barely 1% of all paediatric consultations. For the majority of the respondents other criteria than age were taken into account to consider an adolescent as able to provide informed consent.

The influence of the law on patient's rights on the practice of the Flemish paediatricians anno 2010

BACKGROUND

The law on patients' rights in Belgium was issued in 2002. The new legal framework recommends the establishment of a true dialogue between physician and patient, and it assigns decisive priority to the adolescent rather than to the physician or his parents.

PURPOSE AND METHODS

The purpose of this study is to map the current interpretation of the paediatrician and the realisation of the law in practice. The answers of 117 Flemish paediatricians to an anonymous questionnaire were analyzed.

RESULTS

Only 7.8% of the paediatricians state that they know the law well. 15.5% experience the law as a burden. 20.9% have adopted a different attitude when rendering care to adolescents under impulse of this law. 6.2% say they do not strictly follow the law. 27.8% think that the emancipating thought is too far-reaching. Most paediatricians apply protocols to interpret the traditional values that are stamped as being good medical practice: high quality care (81%), free patient's choice (70.7%), adequate pain control (77.4%). On the other hand paediatricans seldom dispose of procedures regarding the more emancipated amenities in the law such as obtaining informed consent (16.4%), access to the medical file (24.8%) and safe-guarding the privacy (13%). In practice most of the physicians offer the possibility of a free choice in 80% of the cases. All questioned physicians strive for a high quality care, for adequate pain control and for a careful maintained medical file. 79.1% of the physicians transfer to the parents all medical information regarding the adolescent. Proper experience and expertise (80.7%), case by case completed, are most often used as the basis for the judgment about the competence of the adolescent. From the patient's side, little advance is taken to exercise his own rights. Barely 1% of the adolescents consulting a paediatrician use their legal right to autonomously consent to a medical intervention. In barely 0.16% access is requested to the medical file. Practically no complaints are received regarding the law on patients' rights (0.1% in intramural setting, versus 0.001% extramural).

CONCLUSION

The law on patients' rights is, after 8 years of issuance, badly penetrated in the paediatric practice. On the one hand this is due to a poor knowledge of the law as well from the side of the physician as from the side of the adolescent and/or his parents. On the other hand 42.2% of the paediatricians experience difficulties with the practical interpretation of the law because of the lack of applicable guidelines. An important obstacle is the fact that more than a quarter of the paediatricians do not agree with the in the law foreseen autonomy of the adolescents. For that reason, paediatricians urgently need to be instructed in these matters. It is the moral duty of the Society of Paediatrics to organize workshops on these matters and develop clear guidelines concerning this law. Proper application of the legal context, the handling of the watertight procedures and the necessary communication in this respect is indispensable for the confidence and will lower the barrier for adolescents to use the healthcare system.

Seasonal changes of C and N non-structural compounds in the stem sapwood of adult sessile oak and beech trees

We assessed the pools of non-structural nitrogen compounds (NSNC) through a year, thereby addressing the question of whether mature sessile oak [Quercus petraea (Matt.) Liebl.] and beech (Fagus sylvatica L.), which differ in wood anatomy and growth patterns, exhibit contrasting seasonal dynamics of NSNC pools as previously shown for non-structural carbohydrate (NSC) pools. Seasonal fluctuations of NSNC (amino acids and soluble proteins) and NSC (starch and soluble sugars) pools were analyzed in the inner and the outer stem sapwood. In oak, NSC showed marked seasonal variation within the stem sapwood (accumulation during winter and decrease during bud burst and early wood growth), whereas in beech seasonal fluctuations in NSC were of minor amplitude. Even if the distribution and intensity of the NSNC pools differed between the two species, NSNC of the stem sapwood did not show seasonal variation. The most significant change in NSNC pools was the seasonal fluctuation of protein composition. In both species, two polypeptides of 13 kDa (PP13) and 26 kDa (PP26) accumulated during the coldest period in parallel with starch to sugar conversion and disappeared with the onset of spring growth. The absence of seasonal changes in total soluble protein concentration suggests that the polypeptides are involved in the internal nitrogen (N) cycling of the stem rather than in N storage and remobilization to the other growing organs of the tree.

Genetic polymorphism and its potential relation to environmental stress in five populations of the European flounder Platichthys flesus, along the French Atlantic coast

In this study, new DNA markers were explored for the flounder Platichthys flesus. cDNA and genomic sequences of the genes encoding the glyceraldehyde-3-phosphate-deshydrogenase (GAPDH), the cytosolic creatine kinase (CK), the prostaglandin D synthase (PGDS) and the betaine homocysteine methyltransferase (BHMT) were characterized. The tumour suppressor p53 gene structure was already described. A PCR-SSCP (Single Strand Conformation Polymorphism) analysis was finally conducted to study the genetic polymorphism of different populations of flounders collected along the French Atlantic coast. Four highly contaminated French estuaries (Seine, Vilaine, Loire and Gironde) were sampled and compared to a reference estuary (Ster) to explore possible selective effect of the environment on specific allelic frequencies. Our results showed that two loci p53 and PGDS, could be potential markers of chemical stress: p53A allele frequency increased in contaminated systems compared to the reference system. In the Vilaine estuary, PGDS polymorphism could be related to pesticide stress.

Molecular identification and expression of differentially regulated genes of the European flounder, Platichthys flesus, submitted to pesticide exposure

Effects of pesticide exposure on the European flounder, Platichthys flesus, were investigated using a suppression subtractive hybridization method (SSH) to identify up- and down-regulated genes after a 30-day exposure to herbicides (a cocktail of atrazine, diuron, and isoproturon, and a single herbicide, glyphosate). A total of 256 expressed gene sequences were identified as having the potential for being differentially expressed, of which 116 could be identified by homology with databased sequences. The metabolic functions with which they are associated include energy production, general metabolism, signaling, transport, immune system, and structure. Expression of 14 of these genes was analyzed in liver, muscle, and gills by reverse transcriptase-polymerase chain reaction (RT-PCR) under experimental conditions (0, 15, and 30 days of exposure) and under field conditions (sampling in two estuaries displaying different levels of pesticide contamination). This study provides a first basis for studying the response of fish to pesticide exposure and allows the characterization of new potential genetic markers of pesticide contamination in the field.

[Blood transfusion practice]

The publication of the Circular DGS/DHO/Afssaps N(o) 2003-582 of the December 15 2003 relating to the administration of blood and blood components, means that an update of statutory requirements is needed. This article presents the overall process from the writing of prescriptions to the care and monitoring of the transfused patient. An update and a critical analysis of regulations currently in force are presented for each step as well as a description of the main adverse events.

Preclinical validation of the hypoxia tracer 2-(2-nitroimidazol-1-yl)- N-(3,3,3-[(18)F]trifluoropropyl)acetamide, [(18)F]EF3

The 2-nitroimidazole derivative 2-(2-nitroimidazol-1-yl)- N-(3,3,3-trifluoropropyl)acetamide (EF3) is a marker which forms adducts into hypoxic cells. Radiosynthesis of [(18)F]EF3 was recently performed by our group. Our aim was to study the pharmacokinetics, biodistribution, metabolism and specificity for hypoxia of [(18)F]EF3. MCa-4, SCC VII, NFSA, FSA, FSA II or Sa-NH tumour-bearing C3H mice were injected intravenously with [(18)F]EF3 and allowed to breathe air, 10% O(2) or carbogen until sacrifice 5-770 min after injection. Radioactivity was measured ex vivo in various organs, including urine and faeces. Selected organs were additionally processed to measure tracer metabolites with high-performance liquid chromatography. The half-life in blood was 73.9 min. [(18)F]EF3 was eliminated mainly via the kidneys, with 75% of the injected activity found in the urine by 12 h 50 min. The biodistribution was fast and homogeneous except in the brain and the bone, where it was significantly lower, and in the liver and the kidney, where it was significantly higher. In most organs, the exceptions being the gastrointestinal and urinary tract, tissue-to-blood ratios were below or close to unity. In tumours, a relative accumulation of the tracer was observed with time, which, at 220 min after injection, depended on tumour strain and oxygenation conditions, i.e. 10% O(2) significantly increased the tumour-to-muscle ratio whereas carbogen decreased it. [(18)F]EF3 was rapidly metabolised in the kidney and the liver. [(18)F]EF3 is a promising tracer for detection of tumour hypoxia. A phase I study in head and neck cancer patients is in progress at our institution.

K-ras mutation detection by hybridization to a polypyrrole DNA chip

BACKGROUND

Detection of mutations in cancer-related genes is of major importance for both basic knowledge and clinical practice. Several strategies have been developed to diagnose these alterations. We describe a method based on polypyrrole DNA chip technology to detect K-ras gene mutations in tumors.

METHODS

An oligodeoxynucleotide array was constructed on a silicon device by copolymerization of 5'-pyrrole-labeled oligodeoxynucleotides and pyrrole. The samples to be analyzed were then amplified by PCR, and the single-stranded biotin-labeled amplified DNA was specifically hybridized to the addressed probes. Perfectly matched duplexes were detected by fluorescence microscopy using R-phycoerythrin as the detection label. The developed methodology was applied to genotype assignment of K-ras in human samples. The genotypes of 75 DNA genomic samples from colorectal cancer patients were analyzed side by side using direct DNA sequencing and a polypyrrole DNA chip.

RESULTS

The chip method unequivocally defined all of the genotypes. Mutations present at <10% of the wild-type DNA concentration could be distinguished.

CONCLUSIONS

This probe array assay is a rapid and reliable procedure that may be used to detect mutations.

Micro-organisms administered in the benefit of the host: myths and facts

OBJECTIVE

To evaluate the published literature on the potential benefit of micro-organisms on the general well being of the host.

STUDY DESIGN

All published prospective, randomized, placebo-controlled trials with micro-organisms to improve the health of the host were critically reviewed.

RESULTS

According to published data, there is evidence suggesting that Lactobacillus rhamnosus strain GG or Lactobacillus casei strain GG and Saccharomyces boulardii may be of possible benefit for the treatment of several medical conditions. However, published data on the therapeutic effect of other micro-organisms are almost non-existent.

CONCLUSION

Better designed prospective, randomized, and placebo-controlled studies are needed. Most of the present strains have not been selected in a rational way, but apparently represent rather randomly picked isolates. Although the theoretical advantages of micro-organisms administered to the benefit of the host are extremely interesting and promising, results of clinical trials are disappointing.

Characterization of NPY receptors controlling lipolysis and leptin secretion in human adipocytes

In order to characterize neuropeptide Y (NPY) receptors present in human adipocytes, we used selective ligands together with specific molecular probes able to recognize the different NPY receptor subtypes. RT-PCR experiments revealed the presence of Y(1) receptor transcripts with Y(4) and Y(5) and absence of Y(2) signals. Binding studies, using selective radioiodinated ligands, detected a high number (B(max)=497+/-124 fmol/mg protein) of a high affinity binding site only with [(125)I]peptide YY (PYY) and [(125)I](Leu(31), Pro(34))PYY. These sites exhibited a typical Y(1) profile as indicated by the rank order of affinity of NPY analogs and the high affinity of two selective NPY receptor antagonists, SR120819A and BIBP3226. In [(35)S]GTPgammaS binding experiments, PYY activation was totally inhibited by SR120819A and BIBP3226. Both compounds antagonized, with similar efficiency, the antilipolytic effect exerted by NPY in isolated adipocytes. Finally, PYY and Y(1) ligands enhanced adipocyte leptin secretion, an effect totally prevented by SR120819A. Thus, highly expressed in human adipocytes, the Y(1) receptor sustains the strong antilipolytic effect of NPY and exerts a positive action on leptin secretion.

The neuroprotective agent SR 57746A abrogates experimental autoimmune encephalomyelitis and impairs associated blood-brain barrier disruption: implications for multiple sclerosis treatment

Experimental autoimmune encephalomyelitis (EAE) is a T cell autoimmune disorder that is a widely used animal model for multiple sclerosis (MS) and, as in MS, clinical signs of EAE are associated with blood-brain barrier (BBB) disruption. SR 57746A, a nonpeptide drug without classical immunosuppressive properties, efficiently protected the BBB and impaired intrathecal IgG synthesis (two conventional markers of MS exacerbation) and consequently suppressed EAE clinical signs. This compound inhibited EAE-induced spinal cord mononuclear cell invasion and normalized tumor necrosis factor alpha and IFN-gamma mRNA expression within the spinal cord. These data suggested that pharmacological intervention aimed at inhibiting proinflammatory cytokine expression within the central nervous system provided protection against BBB disruption, the first clinical sign of EAE and probably the key point of acute MS attacks. This finding could lead to the development of a new class of compounds for oral therapy of MS, as a supplement to immunosuppressive agents.

Numerical Solution of the Extended Nernst-Planck Model

The main features of a numerical model aiming at predicting the drift of ions in an electrolytic solution upon a chemical potential gradient are presented. The mechanisms of ionic diffusion are described by solving the extended Nernst-Planck system of equations. The electrical coupling between the various ionic fluxes is accounted for by the Poisson equation. Furthermore, chemical activity effects are considered in the model. The whole system of nonlinear equations is solved using the finite-element method. Results yielded by the model for simple test cases are compared to those obtained using an analytical solution. Applications of the model to more complex problems are also presented and discussed. Copyright 1999 Academic Press.

Quantitative method to determine mRNA levels by reverse transcriptase-polymerase chain reaction from leukocyte subsets purified by fluorescence-activated cell sorting: application to peripheral cannabinoid receptors

BACKGROUND

While cytometry is widely used in the detection of cell proteins, its application to quantitative evaluation remains problematic when target proteins or receptors are weakly expressed in cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) is a technique whose sensitivity and specificity make it appropriate for analyzing nucleic acids and thus genes expressed in cells. Combining these two techniques, we developed a method to quantify the transcript expression of the peripheral cannabinoid receptor (CB2-r) in peripheral blood lymphocyte subpopulations and in tonsillar B-cell subpopulations.

METHODS

This strategy first involves quantitative RT-PCR performed kinetically, followed by enzyme detection of PCR products using an oligonucleotide probe sandwich-hybridization assay onto microplates.

RESULTS

B cells exhibit CB2-receptor mRNA levels 10 times higher than those of other lymphocyte subsets. Using this technique, we observed a modulation of CB2-r mRNA level following tonsillar B-cell differentiation. Lastly, this new technology was validated by comparing the mRNA levels of CB2-r with the expression of CB2-r proteins assayed by flow cytometry, using specific CB2-r antibody labelling.

CONCLUSIONS

This method allows precise measurement of the mRNA of CB2-r performed on cell numbers as low as 10(5) after sorting. Its performance, high accuracy, reproducibility, and reliability make it a valuable tool for assaying proteins weakly expressed in cells.

Modulation and functional involvement of CB2 peripheral cannabinoid receptors during B-cell differentiation

Two subtypes of G-protein-coupled cannabinoid receptors have been identified to date: the CB1 central receptor subtype, which is mainly expressed in the brain, and the CB2 peripheral receptor subtype, which appears particularly abundant in the immune system. We investigated the expression of CB2 receptors in leukocytes using anti-CB2 receptor immunopurified polyclonal antibodies. We showed that peripheral blood and tonsillar B cells were the leukocyte subsets expressing the highest amount of CB2 receptor proteins. Dual-color confocal microscopy performed on tonsillar tissues showed a marked expression of CB2 receptors in mantle zones of secondary follicles, whereas germinal centers (GC) were weakly stained, suggesting a modulation of this receptor during the differentiation stages from virgin B lymphocytes to memory B cells. Indeed, we showed a clear downregulation of CB2 receptor expression during B-cell differentiation both at transcript and protein levels. The lowest expression was observed in GC proliferating centroblasts. Furthermore, we investigated the effect of the cannabinoid agonist CP55,940 on the CD40-mediated proliferation of both virgin and GC B-cell subsets. We found that CP55,940 enhanced the proliferation of both subsets and that this enhancement was blocked by the CB2 receptor antagonist SR 144528 but not by the CB1 receptor antagonist SR 141716. Finally, we observed that CB2 receptors were dramatically upregulated in both B-cell subsets during the first 24 hours of CD40-mediated activation. These data strongly support an involvement of CB2 receptors during B-cell differentiation.

Endocytosis by the corneal endothelium. I. Regulation of binding and transport of hemeproteins and peroxidase-conjugated lectins across the tissue

Binding, internalization, and movement of hemeproteins and peroxidase-conjugated lectins across organ cultured rat corneal endothelia has been investigated. Horseradish peroxidase (HRP) type II, bound to the surface, was minimally internalized and was easily washed off. In contrast, HRP-VI bound and was rapidly internalized. Reaction product was observed in vesicles, endosomes, multivesicular bodies, and extended along the length of the intercellular space (ICS) to Descemet's membrane. Studies at 4 degrees C indicated HRP-VI bound uniformly along the surface in a punctate fashion. Exposure to polylysine or mannose significantly decreased uptake. Other tracers such as HRP-VIII, -IX, catalase, and microperoxidase exhibited limited uptake by the tissue. However, endothelia vigorously internalized soybean agglutinin (SBA)-HRP, and reaction product was found intracellularly and within the ICS at the cell/Descemet's membrane interface. Internalization and the appearance of SBA-HRP within the ICS was diminished following polylysine or mannose treatment. Experiments at 4 degrees C indicated that SBA-HRP binding and uptake were temperature sensitive. Wheat germ agglutinin (WGA)-HRP was also strongly endocytosed and reaction product was visualized within vesicles, endosomes, and multivesicular bodies. Although WGA-HRP reaction product was observed within the ICS, none was detected at the level of Descemet's membrane. The WGA competitive sugar N-acetyl-D-glucosamine, reduced endocytosis, whereas exposure to unlabeled WGA and mannose together reduced uptake. These results indicate endothelia exhibit differential uptake of various hemeproteins and lectins which is dependent on charge, mannose receptors, and appropriate surface sugars.

Water absorption in mortar determined by NMR

Nuclear magnetic resonance (NMR) offers the possibility to determine moisture profiles in porous building materials. Moreover, the relaxation of the nuclear magnetic resonance signal can provide additional information on the water distribution in the microstructure. For mortar, it is shown that the transverse relaxation yields information on the distribution of water in the gel pores and capillary pores. Moisture profiles and relaxation were measured during water absorption. The effect of the drying treatment on the microstructure and the water absorption was investigated.

The endogenous cannabinoid anandamide is a lipid messenger activating cell growth via a cannabinoid receptor-independent pathway in hematopoietic cell lines

The effect of anandamide, an endogenous ligand for central (CB1) and peripheral (CB2) cannabinoid receptors, was investigated on the growth of the murine IL-6-dependent lymphoid cell line B9 and the murine IL-3-dependent myeloblastic cell line FDC-P1. In conditions of low serum level, anandamide potentiated the growth of both cytokine-dependent cell lines. Comparison with other fatty acid cannabinoid ligands such as (R)-methanandamide, a ligand with improved selectivity for the CB1 receptor, or palmitylethanolamide, an endogenous ligand for the CB2 receptor, showed a very similar effect, suggesting that cell growth enhancement by anandamide or its analogs could be mediated through either receptor subtype. However, several lines of evidence indicated that this growth-promoting effect was cannabinoid receptor-independent. First, the potent synthetic cannabinoid agonist CP 55940, which displays high affinity for both receptors, was inactive in this model. Second, SR 141716A and SR 144528, which are potent and specific antagonists of CB1 and CB2 receptors respectively, were unable, alone or in combination, to block the anandamide-induced effect. Third, inactivation of both receptors by pretreatment of cells with pertussis toxin did not affect the potentiation of cell growth by anandamide. These data demonstrated that neither CB1 nor CB2 receptors were involved in the anandamide-induced effect. Moreover, using CB2-transfected Chinese hamster ovary cells, we demonstrated that after complete blockade of the receptors by the specific antagonist SR 144528, anandamide was still able to strongly stimulate a mitogen-activated protein (MAP) kinase activity, clearly indicating that the endogenous cannabinoid can transduce a mitogenic signal in the absence of available receptors. Finally, arachidonic acid, a structurally related compound and an important lipid messenger without known affinity for cannabinoid receptors, was shown to trigger MAP kinase activity and cell growth enhancement similar to those observed with anandamide. These findings provide clear evidence for a functional role of anandamide in activating a signal transduction pathway leading to cell activation and proliferation via a non-cannabinoid receptor-mediated process.

Polypyrrole DNA chip on a silicon device: example of hepatitis C virus genotyping

We describe in this article an oligonucleotide array constructed on a silicon device bearing a matrix of addressable 50-microns microelectrodes. Each electrode was covered by a conducting polymer (polypyrrole) grafted by an oligonucleotide (ODN). The DNA chip was prepared by successive electrochemically addressed copolymerizations of 5' pyrrole-labeled ODN and pyrrole. Following hybridization of the biotinylated amplified sample on the chip bearing a series of probes, detection was carried out by fluorescence microscopy through an R-phycoerythrin label. This technology was successfully applied to the genotyping of hepatitis C virus in blood samples. Results show good sensitivity and a high degree of dimensional resolution.

Rapid and large-scale method to detect K-ras gene mutations in tumor samples

We have developed a rapid and large-scale method for the detection of K-ras gene mutations in tumors. First, DNA is amplified by an asymmetric PCR; second, the single-strand dinitrophenyl (DNP)-labeled amplified DNA is hybridized specifically to oligonucleotide probes affixed on a tube. Finally, perfectly matched duplexes are easily detected by a monoclonal anti-DNP antibody bearing 125I. The usefulness of this technique is illustrated by analyzing K-ras codon 12 mutations in human colorectal samples. This reliable assay procedure can be applied to the rapid screening of virtually any genetic disease caused by previously described point mutations.

Evaluation of the automated fluorescent analysis of the H-ras minisatellite after optimized PCR amplification in comparison with a standardized Southern blot technique

Determination of allele sizes? loss of heterozygosity or genetic instability at minisatellite VNTR loci, are routinely performed by the conventional Southern technique. We have investigated the potential use of automated DNA sequencer for the analysis of the H-ras minisatellite. We report the modifications of amplification parameters and electrophoresis conditions on the sequencer. Seventy-one colorectal carcinomas and the corresponding normal tissues were amplified with fluorescent-labeled primers, analyzed on sequencer, and concurrently controlled by Southern blotting. The results on sequencer showed that a Hydrolink matrix used in non-denaturing conditions and a specific analysis software facilitate a more accurate fragment size calculation.

Immediate-early gene expression in ovine brain after cardiopulmonary bypass and hypothermic circulatory arrest

BACKGROUND

Cardiopulmonary bypass (CPB) and hypothermic circulatory arrest (HCA) are associated with neurological injury. Altered immediate-early gene expression occurs rapidly in the brain in response to ischemia, hypoxia, and severe metabolic stress, which results in long-term changes in the molecular phenotype of neurons. This study determined the effects of CPB and HCA on the expression of the immediate-early gene c-fos.

METHODS

Neonatal lambs were subjected to 2 h of CPB at 38 degrees C (n = 4) or 60 min (n = 6), 90 min (n = 7), and 120 min (n = 6) of HCA at 15 degrees C. One hour after terminating CPB at 38 degrees C, the brains were analyzed for FOS-encoding mRNA and FOS-like immunoreactivity in the hippocampal formation. Other animals (n = 15), subjected to the same CPB and HCA protocol, were allowed to survive 3-5 days before their brains were examined for dead neurons.

RESULTS

Minimal c-fos mRNA and FOS proteins were observed in neurons of animals subjected to normothermic bypass and of those that served as controls. Non-neuronal FOS proteins were observed in the choroid plexus, ependyma, and blood vessels at all times, including normothermic CPB, but not in the control animals without CPB. The magnitude of c-fos mRNA expression in hippocampal neurons increased directly with the duration of HCA. In contrast, expression of FOS proteins peaked after 90 min of HCA and declined significantly thereafter. Dead neurons were seen in surviving animals after 2 h of HCA only.

CONCLUSIONS

Cardiopulmonary bypass and HCA alter immediate-early gene expression in the brain. Translational processes are impaired after 120 min of HCA and correlate with neuron death in the hippocampus.

Signaling pathway associated with stimulation of CB2 peripheral cannabinoid receptor. Involvement of both mitogen-activated protein kinase and induction of Krox-24 expression

Cannabinoids, known for their psychoactive effects, also possess immunomodulatory properties. The recent isolation and cloning of the G-protein-coupled peripheral cannabinoid receptor (CB2), mainly expressed in immune tissues, have provided molecular tools to determine how cannabinoid compounds may mediate immunomodulation. We here investigated the CB2 signaling properties using stably transfected Chinese hamster ovary cells expressing human CB2. First, we showed that stimulation by a cannabinoid agonist activated mitogen-activated protein (MAP) kinase in time- and dose-dependent manners. The rank order of potency for MAP kinase activation of cannabinoid agonists correlated well with their binding capacities. Second, we demonstrated that, following MAP kinase activation, cannabinoids induced the expression of the growth-related gene Krox-24, also known as NGFI-A, zif/268, and egr-1. Pertussis toxin completely prevented both MAP kinase activation and Krox-24 induction, even more these responses appeared to be dependent of specific protein kinase C isoforms and independent of inhibition of adenylyl cyclase. A similar coupling of CB2 to a mitogenic pathway and to the regulation of Krox-24 expression was also observed in human promyelocytic cells HL60. Taken together, these findings provide evidence for a functional role of the CB2 receptor in gene induction mediated by the MAP kinase network.

Determination of sinefungin in rat plasma by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method for the determination of sinefungin, a new antiprotozoal drug, in rat plasma has been developed and validated. Sample preparation was performed at 4 degrees C by deproteinization with acetonitrile. Vidarabine was used as an internal standard. Both sinefungin and vidarabine were separated on a C18 column with a mobile phase of ammonium dihydrogenphosphate-acetonitrile (95:5, v/v) and detected by ultraviolet absorbance at 260 nm. Recoveries of sinefungin from plasma were 75 +/- 3.2% and 81 +/- 4.8% following dosage at concentrations of 10 micrograms/ml and 30 micrograms/ml, respectively. Using 250 microliters of rat plasma, the limit of quantitation was 1 microgram/ml sinefungin, and the assay was linear from 1 to 30 micrograms/ml. This method appears sensitive enough to be used in further pharmacokinetic studies of sinefungin in animal models.

Expression of central and peripheral cannabinoid receptors in human immune tissues and leukocyte subpopulations

Two proteins with seven transmembrane-spanning domains typical of guanosine-nucleotide-binding-protein-coupled receptors have been identified as cannabinoid receptors; the central cannabinoid receptor, CB1, and the peripheral cannabinoid receptor, CB2, initially described in rat brain and spleen, respectively. Here, we report the distribution patterns for both CB1 and CB2 transcripts in human immune cells and in several human tissues, as analysed using a highly sensitive and quantitative PCR-based method. CB1 was mainly expressed in the central nervous system and, to a lower extent, in several peripheral tissues such as adrenal gland, heart, lung, prostate, uterus, ovary, testis, bone marrow, thymus and tonsils. In contrast, the CB2 gene, which is not expressed in the brain, was particularly abundant in immune tissues, with an expression level 10-100-fold higher than that of CB1. Although CB2 mRNA was also detected in some other peripheral tissues, its level remained very low. In spleen and tonsils, the CB2 mRNA content was equivalent to that of CB1 mRNA in the central nervous system. Among the main human blood cell subpopulations, the distribution pattern of the CB2 mRNA displayed important variations. The rank order of CB2 mRNA levels in these cells was B-cells > natural killer cells >> monocytes > polymorphonuclear neutrophil cells > T8 cells > T4 cells. The same rank order was also established in human cell lines belonging to the myeloid, monocytic and lymphoid lineages. The prevailing expression of the CB2 gene in immune tissues was confirmed by Northern-blot analysis. In addition, the expression of the CB2 protein was demonstrated by an immunohistological analysis performed on tonsil sections using specific anti-(human CB2) IgG; this experiment showed that CB2 expression was restricted to B-lymphocyte-enriched areas of the mantle of secondary lymphoid follicles. These results suggest that (a) CB1 and CB2 can be considered as tissue-selective antigens of the central nervous system and immune system, respectively, and (b) cannabinoids may exert specific receptor-mediated actions on the immune system through the CB2 receptor.

Expression of central and peripheral cannabinoid receptors in human immune tissues and leukocyte subpopulations

Two proteins with seven transmembrane-spanning domains typical of guanosine-nucleotide-binding-protein-coupled receptors have been identified as cannabinoid receptors; the central cannabinoid receptor, CB1, and the peripheral cannabinoid receptor, CB2, initially described in rat brain and spleen, respectively. Here, we report the distribution patterns for both CB1 and CB2 transcripts in human immune cells and in several human tissues, as analysed using a highly sensitive and quantitative PCR-based method. CB1 was mainly expressed in the central nervous system and, to a lower extent, in several peripheral tissues such as adrenal gland, heart, lung, prostate, uterus, ovary, testis, bone marrow, thymus and tonsils. In contrast, the CB2 gene, which is not expressed in the brain, was particularly abundant in immune tissues, with an expression level 10-100-fold higher than that of CB1. Although CB2 mRNA was also detected in some other peripheral tissues, its level remained very low. In spleen and tonsils, the CB2 mRNA content was equivalent to that of CB1 mRNA in the central nervous system. Among the main human blood cell subpopulations, the distribution pattern of the CB2 mRNA displayed important variations. The rank order of CB2 mRNA levels in these cells was B-cells > natural killer cells >> monocytes > polymorphonuclear neutrophil cells > T8 cells > T4 cells. The same rank order was also established in human cell lines belonging to the myeloid, monocytic and lymphoid lineages. The prevailing expression of the CB2 gene in immune tissues was confirmed by Northern-blot analysis. In addition, the expression of the CB2 protein was demonstrated by an immunohistological analysis performed on tonsil sections using specific anti-(human CB2) IgG; this experiment showed that CB2 expression was restricted to B-lymphocyte-enriched areas of the mantle of secondary lymphoid follicles. These results suggest that (a) CB1 and CB2 can be considered as tissue-selective antigens of the central nervous system and immune system, respectively, and (b) cannabinoids may exert specific receptor-mediated actions on the immune system through the CB2 receptor.

Cannabinoids enhance human B-cell growth at low nanomolar concentrations

This study examined the effect of cannabinoid ligands on human tonsillar B-cells activated either through cross-linking of surface immunoglobulins or ligation of the CD40 antigen. The two synthetic cannabinoids, CP55,940 and WIN55212-2, as well as delta 9-tetrahydrocannabinol (THC), the psychoactive component of marijuana, caused a dose-dependent increase of B-cell proliferation and displayed EC50 at low nanomolar concentrations. This cannabinoid-induced enhancing activity was inhibited by pertussis toxin which suggested a G-protein-coupled receptor process. In addition, the absence of antagonistic effect of SR141716A, a specific CB1 receptor antagonist, together with the demonstration that human B-cells displayed large amount of CB2 receptor mRNAs, led us to assume that the growth enhancing activity observed on B-cells at very low concentrations of cannabinoids could be mediated through the CB2 receptor.

Increased number of substance P positive nerve fibres in interstitial cystitis

OBJECTIVE

To explore the presence of the neuropeptide substance P (SP) in the bladders of rats and humans and to investigate its relationship to mast cells (MCs) in interstitial cystitis (IC), a bladder disorder which occurs mostly in women and is characterized by frequency of voiding, nocturia and debilitating suprapubic pain.

PATIENTS, MATERIALS AND METHODS

Bladder biopsies from eight women with untreated IC (mean age 36 years, range 29-58) and five control patients with no IC were analysed and compared with each other and with bladder tissue from 12 rats. Immunohistochemistry and image analysis were used to examine the density of SP-positive nerve fibres and their relationship with MCs.

RESULTS

SP-containing nerve fibres were present in the bladder of both rats and humans. They were increased only in the submucosa, but not in the detrusor, of IC patients and were frequently seen in juxtaposition to MCs.

CONCLUSION

SP, a neuropeptide secreted from sensory nerve endings, has been implicated in the pathophysiology of pain and has been shown to trigger MC secretion. Moreover, MC secretion by SP is augmented by oestradiol and bladder MCs have been shown to express high affinity oestrogen receptors. A functional relationship between SP and MCs may explain the pathophysiology of the neuro-inflammatory and painful nature of IC.

Rapid diagnosis of Mycobacterium tuberculosis infections by an ELISA-like detection of polymerase chain reaction products

A polymerase chain reaction (PCR) assay was developed for the detection in clinical samples of mycobacteria belonging to the Mycobacterium tuberculosis complex. PCR products were detected with a simple and rapid colormetric method. With this method, 50 fg of M. tuberculosis DNA were detectable with the repetitive DNA-sequence-derived primers, corresponding to 10 genome equivalents. Detection of M. tuberculosis in 258 clinical samples by PCR was compared with detection by culture. PCR was positive for 56 of 57 culture-positive and Ziehl-Neelsen-staining-positive (ZN) samples, 11 of 18 culture-positive and ZN-negative samples. The presence of groEL DNA sequences was also investigated by PCR for all the specimens with the same revelation protocol. Three of the eight false-negative samples with the repetitive element-derived primers were found to contain groEL DNA sequences specific for the Mycobacterium genus. Among the 183 culture-negative samples, 30 were positive by PCR. When clinical data were known, the diagnosis of tuberculosis was established for the patients from whom those samples had been obtained. The results show that the rapid and simplified PCR assay described here is slightly more sensitive than culture and can be used in routine clinical practice.

Detection of loss of heterozygosity by a tube-based assay

Here we report a tube format for detecting loss of heterozygosity in human genomic DNA. This method is based on the detection of a polymorphic restriction site in the selected gene by tube support analysis. After a PCR, amplification products were hybridized to an 125I-labeled oligonucleotide probe and affinity-collected on a tube. The captured hybrids were then subjected to an enzymatic digestion, and the remaining bound radioactivity was measured. The usefulness of this technique is illustrated by analyzing the p53 gene LOH in human colorectal samples. This development, similar to immunoanalysis tests, eliminates the electrophoresis step and makes the results easy to study.

Standardized nested polymerase chain reaction-based assay for detection of human immunodeficiency virus type 1 DNA in whole blood lysates

The routine detection of human immunodeficiency virus type 1 (HIV-1) proviral DNA in clinical samples requires a standardized, simple, and sensitive test. To identify the HIV-1 proviral DNA in blood, we used a solid-phase assay based on the affinity capture and the gamma counting of the amplified product after a nested polymerase chain reaction (AMPLICIS test). In order to simplify the general process, whole-blood lysates rather than peripheral blood mononuclear cell lysates were used for the amplifications. The solid-phase capture and counting of the final amplified products allowed us to define precise interpretive criteria to determine the positivity level of the test. Three new primer sets located in the gag and pol structural genes and in the tat regulatory gene of HIV-1 were studied. The results obtained in 54 seropositive and 120 seronegative individuals demonstrated the ability of the AMPLICIS test to be used for HIV-1 provirus detection: 53 of 54 of the seropositive specimens were found to be positive with at least two primer sets. We also assessed the usefulness of this test for the estimation of the HIV-1 DNA load by the end point dilution method with serial dilutions of blood lysates from 26 HIV-1-seropositive patients.

Two-site direct immunoassay specific for active renin

A sensitive immunoradiometric assay, without an enzymatic step and specific for active human renin, was developed with use of two monoclonal antibodies (MAbs). In this assay system, the first MAb was coupled to magnetic beads (Magnogel); the second one, directed against the active form of the enzyme, was radiolabeled with 125I. The specificity of this assay was demonstrated in experiments measuring the active plasma renin concentration in the presence or absence of inactive renin. The assay, performed in two steps, was sensitive enough to detect 0.9 pg of renin per tube (3.5 ng/L). Intra- or interassay CVs were < 10%. Concentrations of active plasma renin measured in normotensive subjects were between 7 and 40 ng/L.

Direct, simplified, and sensitive assay of angiotensin II in plasma extracts performed with a high-affinity monoclonal antibody

A very simple, fast, and sensitive RIA of angiotensin (Ang) II has been developed, based on a monoclonal antibody with high affinity and specificity, making possible the direct measurement of circulating Ang II in human plasma after solid-phase extraction. The purified monoclonal antibody 4D8 has an association constant of 1.3 x 10(11) L/mol with Ang II and a cross-reactivity of < 1% for Ang I. The assay can detect as little as 0.8 fmol of Ang II in 2 mL of plasma and is not influenced by the presence of Ang I. Analytical recoveries between 112% and 116% were obtained for Ang II added to human plasma at physiological concentrations. Comparison of the RIA with a reversed-phase, high-performance liquid chromatographic method followed by RIA to measure Ang II in human plasma samples from normal and hypertensive subjects--and from normotensive subjects before and after an acute inhibition of angiotensin-converting enzyme with captopril (50 mg)--showed a high degree of correlation (r2 = 0.93) between the two methods.