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Biomedical subjects

D Bernard

Publications and source records attributed to D Bernard.

At least 37 records · Page 2Linked to original sources
PubMed2001

Implementation of an integrated instrument control and data management system for point of care blood gas testing.

Critical care testing in a point of care (POC) setting can be very demanding for the laboratory. Lack of continuous monitoring of the normal functioning of POC instruments leads to late response to technical problems, and frequently results in more comprehensive interventions and reduced instrument availability. As most POC instruments lack adequate data transfer capabilities, manual data entry into the medical records with a high error rate is a component of POC programs. To reduce this data handling drawback of POC testing, our hospital opted for the replacement of the existing analysers with network-ready, expandable analysers (ABL700), linked to an integrated management system (RADIANCE). This new set-up enabled us to have continuous instrument control and maximal data management. The implementation of the integrated management system was well accepted by the operators. The network connectivity has led to real time technical support while reducing the workload by automating data collection.

Blood Gas Analysis↗
PubMed2001

Calmodulin-like skin protein: a new marker of keratinocyte differentiation.

The expression of the calmodulin-like skin protein, a recently discovered new skin-specific calcium binding protein, was studied in cultured keratinocytes, reconstructed human epidermis, and normal human skin. Using a calmodulin-like skin protein specific polyclonal antibody and Western blot analysis we could show that in cultured keratinocytes calmodulin-like skin protein expression is strongly induced after stimulating cell differentiation by increasing the medium calcium concentration. Known modulators of epidermal differentiation such as sodium butyrate and the synthetic retinoid CD 367 strongly affected calmodulin-like skin protein expression. A more than 10-fold increase was observed in the presence of sodium butyrate, whereas CD 367 abolished almost completely calmodulin-like skin protein expression already at nanomolar concentrations. Calmodulin, another calcium binding protein that is expressed throughout the living layers of the epidermis, is not affected by these modulators. In normal human skin, calmodulin-like skin protein expression is restricted to the stratum granulosum and the lower layers of the stratum corneum. From these results we conclude that calmodulin-like skin protein is a new marker of late keratinocyte differentiation with a role distinct from calmodulin.

Biomarkers↗
PubMed2001

Persistence of both peripheral and non-peripheral corneodesmosomes in the upper stratum corneum of winter xerosis skin versus only peripheral in normal skin.

To understand the biochemical abnormalities that underlie the reduced desquamation observed in dry skin, we analyzed corneodesmosome degradation in normal and winter xerosis skin. Western blotting of total proteins from corneocytes obtained by varnish-strippings from the legs of 56 volunteers with normal (26) or xerotic (30) skin was performed using antibodies specific for (corneo)desmosome proteins. In the whole population, the amounts of desmoglein 1 and plakoglobin were found to be correlated, but were not related to the amounts of corneodesmosin. This suggests simultaneous proteolysis for the former proteins differing from that of corneodesmosin. Neither entire desmoplakins nor any proteolysis-derived fragments were detected. The amounts of corneodesmosin, desmoglein 1, and plakoglobin detected were found to be significantly higher in xerotic compared with normal skin extracts. Conventional and freeze-fracture electron microscopy showed the absence of nonperipheral corneodesmosomes in the upper stratum corneum of normal skin but the presence of a significant number of these structures in the same layer of winter xerosis skin. These results provide a more precise description of the proteolysis of corneodesmosome components in the upper cornified layer of the epidermis. They support previous studies demonstrating the importance of corneodesmosome degradation in desquamation and reveal that the nonperipheral corneodesmosomes, which are totally degraded during maturation of the stratum corneum in normal skin, persist in winter xerosis, probably leading to abnormal desquamation.

Adult↗
PubMed2001

Purification and characterization of the endoglycosidase heparanase 1 from human plantar stratum corneum: a key enzyme in epidermal physiology?

A protein exhibiting endoglycosidase activity was purified from plantar stratum corneum to apparent homogeneity in two sequential column chromatographic steps. Protein sequencing revealed its identity with the recently cloned human heparanase 1, an enzyme, the expression of which is reported to be related to the metastasic potential of tumor cells. By using a heparanase 1 specific antibody we were able to demonstrate that, in the plantar stratum corneum, heparanase 1 exists in two forms, the active 50 kDa protein and the inactive 63 kDa form, probably a proform of the enzyme. The antibody also decorated numerous degradation fragments. Reverse transcription polymerase chain reaction studies as well as immunohistochemical analysis using reconstructed and normal human epidermis demonstrated clearly a keratinocyte differentiation related expression of heparanase 1. Interestingly, the antibody also strongly decorated dendritic cells, which after double labeling could be identified to be a subpopulation of the epidermal Langerhans cells. Based on our findings and the known history of this enzyme, we advanced the hypothesis that heparanase 1 has multiple physiologic functions in the epidermis: (i) it plays an important role in epidermal differentiation, possibly by modulating the liberation of heparan sulfate bound (growth) factors; (ii) in the stratum corneum, the endoglycosidase activity of heparanase 1 might be indispensable and represent the first step in the desquamation process; and (iii) in Langerhans cells, its catalytic activity is required for the trans-tissue migration of these cells.

Amino Acid Sequence↗
PubMed2001

Serum alpha-tocopherol and selenium in Belgian infants and children.

Previous studies showed low selenium (Se) concentrations in Belgian children. Serum alpha-tocopherol, retinol, total cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol, selenium (Se), and thiobarbituric acid-reactive substances were examined. In order to obtain further information on the Se status in Belgian children, Se, alpha-tocopherol, retinol, and lipid concentrations were examined and signs of peroxidative lipid damage were evaluated in a subgroup. The study was performed in 524 children (0-14 yr old) during vaccination campaigns. Three age groups were analyzed: 0-1, 1-4, and 4-14 yr. In 87 of them, where sufficient amounts of serum were available, analysis of thiobarbituric acid-reactive substances was done. Infants have high serum alpha-tocopherol concentrations: (23.2 micromol/L [median and interquartile range: 18.6-30.2]) and low Se concentrations (0.37 mol/L [0.27-0.47]). Se concentrations rise significantly during the first 4 yr (p < 0.0001) (Mann-Whitney U-test, tied p-values): 0.70 micromol/L (0.59-0.82); in the 4-14 yr olds, it was 0.75 micromol/L (0.67-0.86). These values remain low compared to results coming from other parts of the world. Alpha-tocopherol concentrations decrease significantly after infancy (p < 0.0001). The ratio alpha-tocopherol/total cholesterol is higher in infants. This is induced by the high vitamin E content of infant formulas. Signs of serum lipid peroxidation could not be detected by analysis of serum malondialdehyde concentrations. High alpha-tocopherol concentrations, as those observed in infant serum lipids, could be one of the protective mechanisms from the peroxidative lipid damages, sometimes observed in a low-Se status.

Adolescent↗
PubMed2000

Identification and cloning of a new calmodulin-like protein from human epidermis.

After separating by two-dimensional gel electrophoresis an extract of total proteins from human stratum corneum, two spots were extracted and analyzed for their peptide sequence. The resulting internal protein sequences provided evidence for the identification of a new calcium-binding protein. Cloning of the corresponding full-length cDNA was achieved by reverse transcriptase-polymerase chain reaction using two keratinocyte libraries, one from proliferating cultured keratinocytes and one from differentiated keratinocytes of reconstructed human epidermis. The cDNA had an open reading frame encoding a new calcium-binding protein of 146 amino acids, a member of the calmodulin family. We named this new protein calmodulin-like skin protein (CLSP), since reverse transcriptase-polymerase chain reaction studies of CLSP expression in 10 different human tissues revealed that this protein was particularly abundant in the epidermis where its expression is directly related to keratinocyte differentiation. Expression of the cloned cDNA in Escherichia coli yielded a recombinant protein which allowed its further characterization. rCLSP is able to bind calcium, and similarly to calmodulin, exposes thereafter hydrophobic parts which most likely interact with target proteins. Epidermal proteins retained by CaM affinity column are quantitatively and qualitatively distinct from those of the rCLSP column. Sequencing of a rCLSP affinity purified protein revealed 100% identity with transglutaminase 3, a key enzyme in terminal differentiation, indicating an important role of CLSP in this process.

Amino Acid Sequence↗
PubMed2000

Comparison of the hemodynamic parameters of open and laparoscopic adrenalectomy for pheochromocytoma.

Laparoscopic adrenalectomy has gained widespread popularity for treating a variety of adrenal disorders including pheochromocytoma, but the effects of pneumoperitoneum on the hemodynamics of patients with catecholamine-secreting tumors are poorly understood. The goal of this study was to compare the effects of carbon dioxide pneumoperitoneum and tumor manipulation on the hemodynamic parameters in two groups of patients with sporadic pheochromocytomas less than 7 cm in size. Group 1 patients (n = 11) underwent lateral transabdominal laparoscopic adrenalectomy, and group 2 (n = 11) underwent adrenalectomy by the open anterior approach. The mean follow-up was 37 months in group 1 (range 26-51 months) and 52 months in group 2 (range 27-72 months). All patients undergoing laparoscopic adrenalectomy experienced intraoperative hypertension (blood pressure > or = 200/90 mmHg), as did 73% with the open approach, but the difference was not significantly different. Intraoperative hypotension (systolic blood pressure < 80 mmHg) occurred in four group 1 patients compared to six patients in group 2. Mean arterial pressure, central venous pressure, and pulmonary capillary wedge pressure were significantly higher in group 1 patients prior to tumor excision, but there was no difference in pulse, cardiac index, or left ventricle work index at any point during the procedure. There were no conversions or complications in the laparoscopic group; one patient in group 2 developed an incisional hernia. Although laparoscopic adrenalectomy for pheochromocytoma is associated with a greater increase in mean arterial pressure, central venous pressure, and pulmonary capillary wedge pressure, the creation of pneumoperitoneum does not significantly change the cardiac index or left ventricle work index. Carbon dioxide pneumoperitoneum is well tolerated in patients with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed2000

Study of the concurrent validity of the Calgary Depression Scale for Schizophrenics (CDSS).

The aim of this study was to investigate the concurrent validity of the French language version of the Calgary Depression Scale for Schizophrenics (CDSS). Ninety-five schizophrenic patients meeting the DSM-III-R criteria were enrolled in the study. The depressive symptoms were evaluated using the Calgary Depression Scale for Schizophrenics (CDSS), Hamilton Depression Rating Scale (HDRS), Montgomery and Asberg Rating Scale (MADRS), and Widlocher Psychomotor Retardation Scale (ERD). The psychotic symptoms were evaluated with the Positive and Negative Syndrome Scale (PANSS) and the extrapyramidal symptoms with the Extrapyramidal Syndrome Rating Scale (ESRS). The CDDS was significantly correlated with all the conventional depression-rating scales. We only found significant positive correlations between the CDSS and the PANSS-positive sub-scale. The CDSS total score was significantly correlated with some PANSS-positive items (delusions and hallucinatory behaviour). No significant correlation between the depression-rating scales and the PANSS-negative sub-scale was observed. For all the depression-rating scales, no correlation with the extrapyramidal symptom was evidenced. The results confirmed the validity of the CDSS in the evaluation of depression in schizophrenia. The relationship between depression and the positive symptoms of schizophrenia is discussed.

Adult↗
PubMed2000

[Sensitized immunofixation: a new technique for analyzing the oligoclonal pattern of CSF immunoglobulins].

Intrathecal immunoglobulin synthesis is observed in more than 90% of all cases of multiple sclerosis, producing a specific CSF IgG oligoclonal electrophoretic pattern. The consensual method used as reference is isoelectric focusing (IEF). We developed a new CSF Ig analysis method by immunofixation (IF). The method includes an immunoenzymatic detection step performed directly on the gel allowing the use of unconcentrated CSF and avoiding the blotting step. The reliability of this method was established by the analysis of 210 CSF/serum pairs including defined, probable and possible MS, other inflammatory CNS diseases and controls (noninflammatory CNS diseases and peripheral nervous system diseases). Intrathecal IgG synthesis was detected in 95.5% of defined MS cases. The specificity for CNS inflammatory diseases including MS diagnosis, evaluated by comparison with controls, was 98.8%. This new method is quicker and visual interpretation is easier than with IEF. It is a semi-automated method that should be considered for standardization of CSF IgG analysis.

Adult↗
PubMed1999

Embryonic death of Mek1-deficient mice reveals a role for this kinase in angiogenesis in the labyrinthine region of the placenta.

Mek is a dual-specificity kinase that activates the extracellular-signal-regulated (Erk) mitogen-activated protein (MAP) kinases upon agonist binding to receptors. The Erk MAP kinase cascade is involved in cell-fate determination in many organisms. In mammals, this pathway is proposed to regulate cell growth and differentiation. Genetic studies have shown that although a single mek gene is present in Caenorhabditis elegans, Drosophila and Xenopus, two mek homologs, Mek1 and Mek2, are present in the mammalian cascade. In the present study, we describe a mutant mouse line in which the mek1 gene has been disrupted by insertional mutagenesis. The null mutation was recessive lethal, as the homozygous mutant embryos died at 10.5 days of gestation. Histopathological analyses revealed a reduction in vascularization of the placenta that was due to a marked decrease of vascular endothelial cells in the labyrinthine region. The failure to establish a functional placenta probably explains the death of the mek1-/- embryos. Cell-migration assays indicated that mek1-/- fibroblasts could not be induced to migrate by fibronectin, although the levels of Mek2 protein and Erk activation were normal. Re-expression of Mek1 in the mutant mouse embryonic fibroblasts (MEFs) restored their ability to migrate. Our findings provide genetic evidence that establishes the unique role played by Mek1 in signal transduction. They also suggest that mek1 function is required for normal response to angiogenic signals that might promote vascularization of the labyrinthine region of the placenta.

Animals↗
PubMed1999

CD95 (Fas/Apo-1) as a receptor governing astrocyte apoptotic or inflammatory responses: a key role in brain inflammation?

Astrocytes are a major cellular component of the brain that are capable of intense proliferation and metabolic activity during diverse inflammatory brain diseases (such as multiple sclerosis, Alzheimer's dementia, tumor, HIV encephalitis, or prion disease). In this biological process, called reactive gliosis, astrocyte apoptosis is frequently observed and could be an important mechanism of regulation. However, the factors responsible for apoptosis in human astrocytes are poorly defined. Here, we report that short term cultured astrocytes derived from different brain regions express significant levels of CD95 at their surface. Only late passage astrocytes are sensitive to CD95 ligation using either CD95 mAb or recombinant CD95 ligand. Blocking experiments using caspase inhibitors with different specificities (DEVD-CHO, z-VAD-fmk, and YVAD-cmk), an enzymatic activity assay, and immunoblotting show that CPP32/caspase-3 play a prominent role in CD95-induced astrocyte death. In contrast, early passage astrocytes are totally resistant to death, but a significant increase in astrocytic IL-8 secretion (p < 0.001, by Wilcoxon's test for paired samples) is observed after CD95 triggering. Production of IL-8 contributes to the resistance of astrocytes to CD95 ligation. Furthermore, in the presence of IFN-gamma, resistant astrocytes became sensitive to CD95-mediated death. These data suggest that microenvironmental factors can influence the consequences of CD95 ligation on astrocytes. Therefore, we propose that CD95 expressed by human astrocytes plays a pivotal role in the regulation of astrocyte life and death and may be a key factor in inflammatory processes in the brain, such as reactive gliosis.

Adjuvants, Immunologic↗
PubMed1999

Flow cytometric monitoring of red blood cell chimerism after bone marrow transplantation.

Chimerism after bone marrow transplantation (BMT) was investigated by flow cytometry analysis of red blood cells (RBCs) and of reticulocytes using a series of selected monoclonal or polyclonal antibodies directed against ABO, Rhesus, Kell, Duffy or MNSs antigens. The method allows the routine detection of less than 0.1% of positive cells in artificial mixed field populations. Blood samples from 135 patients undergoing BMT were investigated around days 15, 30, 45, 60, 90, 180, and then every 6 months after transplantation. Characteristic patterns showing expression of donor red blood cell antigens (expansion markers) and concomitant decrease of recipient specific antigens (depletion markers) within days 16-20 were observed for 125 successfully engrafted patients. Distinct patterns were obtained in 10 patients. A delay in engraftment was evidenced in four patients by the absence of chimerism during the first 6 months without any sign of relapse. Re-appearance of recipient RBCs and reticulocytes was observed in five patients; it was consistent with relapse that was later confirmed by clinical, haematological and cytogenetic studies. Finally, a stable and partial chimerism with 20% of RBCs expressing a marker from the recipient was observed in one patient without any sign of relapse. The reported investigation demonstrated that flow cytometry of RBCs and reticulocytes represents a powerful method to efficiently monitor bone marrow transplanted patients on a long-term basis.

Adolescent↗
PubMed1999

Three-point velocity correlation functions in two-dimensional forced turbulence.

We present a simple exact formula for three-point velocity correlation functions in two-dimensional turbulence which is valid at all scales and which interpolates between the direct and inverse cascade regimes. As expected, these correlation functions are universal in these extreme regimes. We also discuss the effects of anisotropy and friction.

Journal Article↗
PubMed1999

An exploration of the psychometric properties of the French version of the Positive and Negative Syndrome Scale.

The psychometric properties of the French version of the Positive and Negative Syndrome Scale (PANSS) were studied in a population of 85 patients diagnosed with schizophrenia in accordance with Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. The results of the study of the properties (internal consistency and principal-component analysis) of the initial structure with 3 scales (positive, negative, and general psychopathology) led us to investigate other factorial structures. We thus isolated a 5-factor structure (negative, hostility, positive, disorganization, and anxiety), explaining 54.7% of the total variance. The internal consistency of the 5 factors isolated was good (0.79, negative factor; 0.71, hostility factor; 0.77, positive factor; 0.66, disorganization factor; and 0.61, anxiety factor). The 3-subscale structure of the PANSS is discussed.

Adult↗
PubMed1998

Functional overlap between murine Inpp5b and Ocrl1 may explain why deficiency of the murine ortholog for OCRL1 does not cause Lowe syndrome in mice.

The oculocerebrorenal syndrome of Lowe (OCRL) is an X-linked human genetic disorder characterized by mental retardation, congenital cataracts, and renal tubular dysfunction. The Lowe syndrome gene, OCRL1, encodes a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in the Golgi complex. The pathogenesis of Lowe syndrome due to deficiency of a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in the Golgi complex is unknown. We have used targeted disruption in embryonic stem cells to make mice deficient in Ocrl1, the mouse homologue for OCRL1, as an animal model for the disease. Surprisingly, mice deficient in Ocrl1 do not develop the congenital cataracts, renal Fanconi syndrome, or neurological abnormalities seen in the human disorder. We hypothesized that Ocrl1 deficiency is complemented in mice by inositol polyphosphate 5-phosphatase (Inpp5b), an autosomal gene that encodes a phosphatidylinositol bisphosphate 5-phosphatase highly homologous to Ocrl1. We created mice deficient in Inpp5b; the mice were viable and fertile without phenotype except for testicular degeneration in males beginning after sexual maturation. We crossed mice deficient in Ocrl1 to mice deficient in Inpp5b. No liveborn mice or embryos lacking both enzymes were found, demonstrating that Ocrl1 and Inpp5b have overlapping functions in mice and suggesting that the lack of phenotype in Ocrl1-deficient mice may be due to compensating Inpp5b function.

Amino Acid Sequence↗
PubMed1998

Treatment of malnutrition with 1.1% amino acid peritoneal dialysis solution: results of a multicenter outpatient study.

A peritoneal dialysis (PD) solution containing 1.1% amino acids as the osmotic agent was evaluated in a 3-month randomized, prospective, open-label study in malnourished PD patients. Patients in the treatment group (DAA) received one or two exchanges daily with the amino acid solution, depending on tolerance, in place of glucose solutions. Controls (DD) received their usual therapy with glucose dialysate. Fifty-four DAA and 51 DD patients completed the study. In DAA, but not in DD patients, there was a significant increase at month 3 in serum insulin-like growth factor-1 (IGF-1) levels and significant decreases in serum potassium (all 3 months) and inorganic phosphorus levels (months 1 and 3), indicating a general anabolic response. Prealbumin and transferrin levels were significantly increased in DAA but not in DD patients at month 1, but the groups did not differ at months 2 and 3. In patients with baseline albumin levels less than 3.5 g/dL (bromcresol green [BCG] method), DAA patients showed increases in albumin, transferrin (months 1 and 2), and prealbumin levels (all 3 months) relative to baseline values, whereas these serum protein levels were unchanged in DD patients, although the changes from baseline did not differ between groups. In this subgroup, midarm muscle circumference (MAMC) did not change in DD or DAA patients. In patients with baseline albumin levels of 3.5 g/dL or greater, DD patients had decreases in albumin and total protein levels at all 3 months and in prealbumin levels at months 1 and 2, relative to baseline. In DAA patients, there were fewer changes in serum proteins. MAMC increased significantly from baseline in DAA but not in DD patients, although changes from baseline did not differ between DAA and DD groups. DAA patients showed no changes in peritoneal membrane transport characteristics. The results indicate that treatment with one or two exchanges daily of this amino acid-based PD solution is safe and provides nutritional benefit for malnourished PD patients.

Amino Acids↗