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Biomedical subjects

J Messer

Publications and source records attributed to J Messer.

At least 37 records · Page 2Linked to original sources

Severe hypernatremic dehydration in an infant with Netherton syndrome.

Netherthon syndrome is a rare autosomal recessive disease characterized by ichthyosis, the characteristic hair abnormality trichorrhexis invaginata and atopic manifestations. We report a female child with the severe hypernatremic dehydration form of the Netherton syndrome born as the first child of consanguineous parents. Ichthyosis was present at birth. She was admitted to the intensive care unit at the age of 4 days with important loss of weight and dehydration. Severe hypernatremia and convulsions occurred. Despite intensive care the baby died at the age of 11 days. The diagnosis of Netherton syndrome was confirmed by the finding of the pathognomonic hair shaft anomaly trichorrhexis invaginata (bamboo hair) and premature lamellar body secretion and foci of electron-dense material in the intercellular spaces of stratum corneum as relatively specific markers for Netherton syndrome. Netherton syndrome is characterized by a large variability in phenotypic expression. The major neonatal complication is the hypernatremic dehydration, which can be fatal as in this patient or complicated by neurologic signs (intracranial hemorrhage) and secondary sequellae. Molecular studies revealed a mutation in SPINK 5, encoding a serine protease inhibitor. Prenatal diagnosis was performed in the second pregnancy and showed that the fetus was equally affected.

Carrier Proteins↗

[Phrenic nerve paralysis of obstetrical origin: favorable course using continuous positive airway pressure].

INTRODUCTION: Isolated diaphragmatic paralysis due to obstetrical factors is rare and therapeutic management modalities are not quite clear. CASE REPORT: A neonate born by breech delivery presented with respiratory distress due to isolated paralysis of the right hemidiaphragm. The clinical course was progressive, his condition worsening with oxygen supplementation. Continuous positive airway pressure (CPAP) delivered via a nasal cannula was started in the one-month-old child, inducing gradual improvement towards recovery at the age of two months and a half. CONCLUSION: Non-invasive nasal CPAP should be proposed for the treatment of phrenic nerve obstetrical palsy before introducing more invasive ventilation techniques. Surgical plication should be delayed until the child reaches the age of at least three months.

Birth Injuries↗

Reductive metabolism of Cr(VI) by cysteine leads to the formation of binary and ternary Cr--DNA adducts in the absence of oxidative DNA damage.

Carcinogenic chromium(VI) compounds require reduction for the induction of genotoxicity. In this work, we examined a spectrum of DNA damage produced in Cr(VI)-cysteine reactions at neutral pH. Cr(VI) reduction followed single-component kinetics and led to a significant oxidation of 2',7'-dichlorofluoroscein (DCFH). The presence of residual Fe and/or Cu resulted in an increased level of oxidation of DCFH, and the removal of adventitious metals required rigorous purification of cysteine. DNA breakage and abasic sites were not detected, suggesting that DNA is much less susceptible to oxidation than DCFH. Cr(VI) reduction led to the extensive formation of Cr-DNA adducts and Cys-Cr-DNA and interstrand DNA-DNA cross-links. Cr-DNA binding resulted in unwinding of supercoiled DNA and a greater stability of the DNA duplex to denaturation. Ionically bound Cr comprised 40-60% of the total DNA-bound Cr, while the remaining Cr-DNA complexes represented stable Cr-DNA adducts that exhibited significant resistance to dissociation by EDTA. The yield of Cr-DNA adducts was strongly influenced by the nature of the buffer that was used. Phosphate buffer completely blocked Cr-DNA binding, whereas adduct formation in organic buffers was largely dependent on the extent of buffer ionization. The level of formation of Cr-DNA adducts was several times higher at pH 6 which resulted from lower levels of buffer ionization and diminished competition from hydroxyl ions. Yield of a number of Cr-DNA and Cys-DNA adducts increased linearly as a function of Cr(VI) concentration, whereas formation of interstrand DNA cross-links exhibited exponential dose dependence. Approximately 60-90 min was required to convert a Cr-DNA monoadduct into a DNA-DNA cross-link. Prolonged incubations at alkaline conditions led to a selective cleavage of cross-linked DNA. The alkali sensitivity of Cr-adducted DNA suggests that results of alkaline elution analysis of DNA damage in cells require a more cautious interpretation. Overall, a spectrum of DNA damage derived from Cr(VI)-cysteine reactions was similar to that found in exposed cells.

Animals↗

Characterization of [(3)H]Quisqualate binding to recombinant rat metabotropic glutamate 1a and 5a receptors and to rat and human brain sections.

We have investigated the binding properties of [(3)H]quisqualate to rat metabotropic glutamate (mGlu) 1a and 5a receptors and to rat and human brain sections. Saturation isotherms gave K:(D) values of 27 +/- 4 and 81 +/- 22 nM: for mGlu1a and mGlu5a receptors, respectively. Several compounds inhibited the binding to mGlu1a and mGlu5a receptors concentration-dependently. (S:)-4-Carboxyphenylglycine, (S:)-4-carboxy-3-hydroxyphenylglycine, and (R,S)-1-aminoindan-1,5-dicarboxylic acid, which completely inhibited [(3)H]quisqualate binding to the mGlu5a receptor, were inactive in a functional assay using this receptor. The distribution and abundance of binding sites in rat and human brain sections were studied by quantitative receptor radioautography and image analysis. Using 10 nM: [(3)H]quisqualate, a high density of binding was detected in various brain regions with the following rank order of increasing levels: medulla, thalamus, olfactory bulb, cerebral cortex, spinal cord dorsal horn, olfactory tubercle, dentate gyrus molecular layer, CA1-3 oriens layer of hippocampus, striatum, and cerebellar molecular layer. The ionotropic component of this binding could be inhibited by 30 microM: kainate, revealing the distribution of mGlu1+5 receptors. The latter were almost completely inhibited by the group I agonist (S:)-3,5-dihydroxyphenylglycine. The binding profile correlated well with the cellular sites of synthesis and regional expression of the respective group I receptor proteins revealed by in situ hybridization histochemistry and immunohistochemistry, respectively.

Animals↗

[Buprenorphine and pregnancy. Analysis of 24 cases].

BACKGROUND: Maintenance therapy of drug-addict mothers with medical and psychosocial support may reduce complications (prematurity, growth retardation, fetal distress and fetal death). Methadone has been widely used during pregnancy with beneficial effects. Buprenorphine (BUP) is used more and more and shows the same beneficial effects. PATIENTS AND METHOD: Twenty-four pregnant women received BUP and their infants were enrolled in the study. Thirteen retrospective (GI) and 11 prospective (GII) cases were studied. In the GII, the women were treated and followed up in an interdisciplinary manner. RESULTS: Complications in GII were less frequent than in GI: 9 vs 30% of prematurity, 9 vs 46% of fetal growth retardation and 0 vs 23% of acute fetal distress. However, the frequency of withdrawal syndrome was the same in both groups, 63 vs 69%, though improvements came more rapidly in GII. CONCLUSION: This study shows that the use of BUP during pregnancy, combined with medical and psychosocial support, may reduce addiction complications. This support has to be maintained after the birth.

Adult↗

High-versus low-dose erythropoietin in extremely low birth weight infants. The European Multicenter rhEPO Study Group.

OBJECTIVE: To investigate whether a weekly 1500 IU/kg dose of recombinant human erythropoietin (rhEPO) is more effective than a dose of 750 IU/kg/week in preventing anemia and reducing the transfusion need in infants with birth weights less than 1000 gm. STUDY DESIGN: In a randomized, double-blind, multicenter trial, 184 infants with birth weights between 500 and 999 gm were treated with either rhEPO 750 (low-dose group) or 1500 IU/kg/week (high-dose group) from day 3 of life until 37 weeks' corrected age. RESULTS: Thirty-two percent of the infants in each group did not receive any transfusion during the treatment period. The total volume of erythrocytes received was similar in each group. The success rate, defined as no transfusion needed and hematocrit value 0.30 L/L or greater, was 27.6% in the low-dose and 29.5% in the high-dose group (p = 0.96). CONCLUSION: Doubling the rhEPO dose of 750 IU/kg/week is not indicated in infants with birth weights less than 1000 gm.

Anemia↗

Impaired glycolysis and protein catabolism induced by acid in L6 rat muscle cells.

BACKGROUND: In skeletal muscle, metabolic acidosis stimulates protein degradation and oxidation of branched-chain amino acids. This could occur to compensate for impairment of glucose utilization induced by acid. METHODS: To test this hypothesis, glycolysis and protein degradation (release of [14C]-phenylalanine) were measured in L6 skeletal muscle cells cultured in Eagle's minimum essential medium at pH 7.1 or 7.5 for up to 3 days. RESULTS: No marked changes in total DNA or in cell viability were detected, nor was there any significant effect on intracellular pH or the water content of the cells (which is thought to be a key regulator of protein turnover, especially in liver). In spite of this, acid stimulated protein degradation, induced net protein loss from the cultures, inhibited glucose uptake and glycolysis (lactate output) and was associated with increased [1-14C]-leucine oxidation. Effects on protein degradation and glycolysis were gradual, reaching a maximum after 20-30 h. To investigate whether glycolytic flux itself can influence protein degradation, increased glycolysis was simulated by adding glucose (20 mmol L-1) or pyruvate (1 mmol L-1) to the medium. At pH 7.1, neither addition had any effect on protein degradation. CONCLUSION: Although acid-induced protein wasting is associated with impaired glycolysis, no obligatory coupling exists between glycolytic flux and protein degradation.

Acidosis↗

In vitro binding properties in rat brain of [3H]Ro 25-6981, a potent and selective antagonist of NMDA receptors containing NR2B subunits.

The in vitro binding of a new subtype-selective NMDA receptor antagonist, [3H]Ro 25-6981, to rat brain membranes and sections was characterized. The compound bound to a single site on the membranes with a K(D) of 3 nM and a Bmax of 1.6 pmol/mg of protein. Specific binding, defined with a new NR2B-specific antagonist, Ro 04-5595 [1-(4-chlorophenyl)-2-methyl-6-methoxy-7-hydroxy-1,2,3,4-tetrahydroisoqu inoline], at 10 microM, was fully inhibited by several compounds with the following rank order of affinities--Ro 25-6981 > CP-101,606 > Ro 04-5595 = ifenprodil >> eliprodil > haloperidol > spermine > spermidine > MgCl2 > CaCl2--and partially inhibited by competitive glutamate recognition site antagonists. A high density of binding sites was detected, radioautographically, in several layers of the cerebral cortex, in the hippocampus, dentate gyrus, tuberculum olfactorium, caudate putamen, medium densities in the globus pallidus, thalamus, spinal cord dorsal horn, and motoneurons, whereas the cerebellum, pons, and medulla were, with a few exceptions, e.g., locus coeruleus, poorly labeled. Overall, the distribution of [3H]Ro 25-6981 binding sites correlated well with that of NR2B (but not NR2A) transcripts, revealed by in situ hybridization histochemistry. The high affinity of [3H]Ro 25-6981 for NR2B-containing receptors renders this compound the ligand of choice to study the regulation of NR2B-containing receptor expression.

Animals↗

Binding characteristics of a potent AMPA receptor antagonist [3H]Ro 48-8587 in rat brain.

A new AMPA receptor antagonist, Ro 48-8587, was characterized pharmacologically in vitro. It is highly potent and selective for AMPA receptors as shown by its effects on [3H]AMPA, [3H] kainate, and [3H] MK-801 binding to rat brain membranes and on AMPA- or NMDA-induced depolarization in rat cortical wedges. [3H]Ro 48-8587 bound with a high affinity (KD = 3 nM) to a single population of binding sites with a Bmax of 1 pmol/mg of protein in rat whole brain membranes. [3H]Ro 48-8587 binding to rat whole brain membranes was inhibited by several compounds with the following rank order of potency: Ro 48-8587 > 6-nitro-7-sulphamoylbenzo[f] quinoxaline-2,3-dione (NBQX) > YM 90K > 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) > quisqualate > AMPA > glutamate > kainate > NMDA. The distribution and abundance of specific binding sites (approximately 95% of total) in sections of rat CNS, revealed by quantitative receptor radioautography and image analysis, indicated a very discrete localization. Highest binding values were observed in cortical layers (binding in layers 1 and 2 > binding in layers 3-6), hippocampal formation, striatum, dorsal septum, reticular thalamic nucleus, cerebellar molecular layer, and spinal cord dorsal horn. At 1 nM, the values for specific binding were highest in the cortical layers 1 and 2 and lowest in the brainstem (approximately 2.6 and 0.4 pmol/mg of protein, respectively). Ro 48-8587 is a potent and selective AMPA receptor antagonist with improved binding characteristics (higher affinity, selectivity, and specific binding) compared with those previously reported.

Animals↗

Characterization of (2S,2'R,3'R)-2-(2',3'-[3H]-dicarboxycyclopropyl)glycine binding in rat brain.

[(2S,2'R,3'R)-2-(2',3'-[3H]Dicarboxycyclopropyl)glycine ([3H]DCG IV) binding was characterized in vitro in rat brain cortex homogenates and rat brain sections. In cortex homogenates, the binding was saturable and the saturation isotherm indicated the presence of a single binding site with a K(D) value of 180 +/- 33 nM and a Bmax of 780 +/- 70 fmol/mg of protein. The nonspecific binding, measured using 100 microM LY354740, was <30%. NMDA, AMPA, kainate, L(-)-threo-3-hydroxyaspartic acid, and (S)-3,5-dihydroxyphenylglycine were all inactive in [3H]DCG IV binding up to 1 mM. However, several compounds inhibited [3H]DCG IV binding in a concentration-dependent manner with the following rank order of potency: LY341495 = LY354740 > DCG IV = (2S,1'S,2'S)-2-(2-carboxycyclopropyl)glycine > (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid > (2S,1'S,2'S)-2-methyl-2-(2-carboxycyclopropyl)glycine > L-glutamate = ibotenate > quisqualate > (RS)-alpha-methyl-4-phosphonophenylglycine = L(+)-2-amino-3-phosphonopropionic acid > (S)-alpha-methyl-4-carboxyphenylglycine > (2S)-alpha-ethylglutamic acid > L(+)-2-amino-4-phosphonobutyric acid. N-Acetyl-L-aspartyl-L-glutamic acid inhibited the binding in a biphasic manner with an IC50 of 0.2 microM for the high-affinity component. The binding was also affected by GTPgammaS, reducing agents, and CdCl2. In parasagittal sections of rat brain, a high density of specific binding was observed in the accessory olfactory bulb, cortical regions (layers 1, 3, and 4 > 2, 5, and 6), caudate putamen, molecular layers of the hippocampus and dentate gyrus, subiculum, presubiculum, retrosplenial cortex, anteroventral thalamic nuclei, and cerebellar granular layer, reflecting its preferential (perhaps not exclusive) affinity for pre- and postsynaptic metabotropic glutamate mGlu2 receptors. Thus, the pharmacology, tissue distribution, and sensitivity to GTPgammaS show that [3H]DCG IV binding is probably to group II metabotropic glutamate receptors in rat brain.

Animals↗

In vitro binding characteristics of a new selective group II metabotropic glutamate receptor radioligand, [3H]LY354740, in rat brain.

The in vitro binding of [3H]LY354740, the first high affinity group II-selective metabotropic glutamate (mGlu) receptor radioligand, was characterized in rat cortical, hippocampal, and thalamic membranes as well as in rat brain sections. [3H]LY354740 binding was saturable in all regions investigated. Nonspecific binding (in the presence of 10 microM DCG-IV) was approximately 8% of the total. Ionotropic glutamate receptor agonists, N-methyl-D-aspartate, (R,S)-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid/kainate, a Na+-dependent glutamate uptake blocker as well as a group I-selective mGlu receptor agonist (all up to 1 mM) did not inhibit [3H]LY354740 binding to cortical membranes. However, several known metabotropic receptor ligands inhibited the binding with the following rank order of potency: LY354740 = LY341495 > (2S,2'R, 3'R)-2-(2',3'-dicarboxycyclopropyl)glycine = (2S,1'S, 2'S)-2-(2-carboxycyclopropyl)glycine > glutamate = (1S, 3R)-1-aminocyclopentane-1,3-dicarboxylic acid > (2S,1'S, 2'S)-2-methyl-2-(2-carboxycyclopropyl)-glycine > quisqualate > ibotenate > L-2-amino-3-phosphonopropionic acid = (S)-alpha-methyl-4-carboxyphenylglycine > L-(+)-2-amino-4-phosphonobutyric acid. N-Acetyl-aspartyl-glutamate, (2S)-alpha-ethylglutamic acid, and (R, S)-alpha-methyl-4-phosphonophenylglycine inhibited [3H]LY354740 binding in a biphasic manner. Guanosine-5'-O-(3-thiotriphosphate concentration-dependently and almost completely inhibited the binding. Finally, in parasagittal sections of rat brain, a high density of specific binding was observed in the accessory olfactory bulb, cortical regions (layers 1-3 > 4-6), caudate putamen, molecular layers of the hippocampus and dentate gyrus, presubiculum, retrosplenial cortex, anteroventral thalamic nuclei, and cerebellar granular layer, reflecting its preferential (perhaps not exclusive) affinity for presynaptic and postsynaptic mGlu2 receptors. Thus, the pharmacology, tissue distribution, and sensitivity to guanosine-5'-O-(3-thiotriphosphate show that [3H]LY354740 binding probably occurs to group II mGlu receptors in rat brain.

ATP-Binding Cassette Transporters↗

Evaluation of interleukin-6 and soluble receptors of tumor necrosis factor for early diagnosis of neonatal infection.

OBJECTIVE: To evaluate plasma levels of interleukin-6 (IL-6) and soluble tumor necrosis factor receptors (sTNF-R) 55 and 75 in neonates as a contribution to the early diagnosis of infection. STUDY DESIGN: We prospectively measured IL-6 and sTNF-R 55 and sTNF-R 75 plasma levels in 157 newborn infants admitted to our regional neonatal center in a 3-month period and in cord blood of 131 newborn infants delivered in our obstetrics unit. C-reactive protein was sequentially determined after admission. Newborn infants were classified into four groups: group 0, not infected; group 1, possibly infected; group 2a, infected (culture positive), and group 2b, probably infected (culture negative). We looked for the optimal cutoff point of these parameters, using the receiver operating characteristics (ROC) curve. RESULTS: IL-6 levels were significantly higher in group 2 (n = 11; median level, 250 pg/ml; range, 0 to 81,000), group 2b (n = 25; median level, 750 pg/ml; range, 0 to 180,000), and group 1 (n = 35; median level, 160 pg/ml; range 0 to 10,000), in comparison with group 0 (n = 217; median level, 0 pg/ml; range, 0 to 3400). A cutoff value of 100 pg/ml or greater obtained by the ROC method gives a sensitivity of 83.3% and a specificity of 90.3%. For inborn infants (n = 220) sampled at birth, sensitivity is 100% and specificity 92.3%. This high sensitivity persists until the twelfth hour of life. The sTNF-R 55 levels are significantly higher in group 2a (median, 12.0 ng/ml; range, 3.2 to 24.4). In group 2b (median, 7.0 ng/ml; range, 3.0 to 25.2), and in group 1 (median, 7.0 ng/ml; range, 2.5 to 18.9) than in group 0 (median, 3.9 ng/ml; range, 1.5 to 15.0), and with a cutoff value of 6 ng/ml, sensitivity is 75% and specificity 69%. The sTNF-R 75 levels are significantly higher in group 2a (median, 17.0 ng/ml; range, 7.2 to 48.8). In group 2b (median, 11.2 ng/ ml; range, (2.0 to 31.3), and in group 1 (median, 10.6 ng/ml; range, 2.0 to 33.0); than in group 0 (median, 7.0 ng/ml; range, 1 to 23.0). With a cutoff value of 9 ng/ ml, sensitivity is 80% and specificity 67%. Sensitivity of C-reactive protein is low initially but improves with time. Combining IL-6 with C-reactive protein provides the possibility of identifying the majority of infected infants in the postnatal period. CONCLUSION: A plasma IL-6 level of 100 pg/ml or greater, obtained before the twelfth hour of life, appears to be an ideal marker for detecting early-onset neonatal infection with a high degree of sensitivity and specificity. After the twelfth hour, the combined determination of IL-6 and C-reactive protein may be equally useful. The sTNF-R levels appear to be less useful in the early diagnosis of infection because of their smaller magnitude of variation.

Antigens, CD↗