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Biomedical subjects

M Bernard

Publications and source records attributed to M Bernard.

At least 127 records · Page 7Linked to original sources
PubMed1996

Acute and long-term dose-response study of quinapril on hormonal profile and tissue angiotensin-converting enzyme in Wistar rats.

Therapeutic response to angiotensin-converting enzyme (ACE) inhibitors was reported to be better related to tissular than to circulating levels of ACE inhibition, especially during chronic therapy. We studied the relations between plasma concentrations of angiotensin I (AI), plasma renin activity (PRA), angiotensin II (AII), and aldosterone (by radioimmunoassay, RIA) and levels of serum and tissue ACE activities during acute and chronic quinapril administration in rats. Forty-eight male Wistar rats received quinapril by gavage for either 1 day (n = 24) or 15 days (n = 24) at different doses (control, 0.1, 1, and 10 mg/kg/day; 6 rats at each dose). Plasma hormonal parameters, serum, and tissue (lung, heart, and aorta) ACE activities were measured 3 h after the last gavage. Significant dose-dependent inhibitions of serum and lung ACE during acute and chronic treatments were observed (p < 0.05). Degrees of serum and heart ACE inhibition (at 0.1 mg/kg/day) were significantly lower with chronic than with acute treatment (p < 0.05). Degree of inhibition in lung, which represents the main source of total ACE, was similar during acute and chronic treatments. Among plasma hormonal parameters, plasma AI was correlated to PRA and showed the best correlation with ACE inhibition. After logarithmic transformation, log AI was significantly correlated to ACE activity in lung during chronic treatment (r = -0.85, p < 0.05). This parameter may provide a useful index for ACE inhibitor dosage adjustment during chronic therapy.

Aldosterone↗
PubMed1996

Hydroxyindole-O-methyltransferase in the chicken retina: immunocytochemical localization and daily rhythm of mRNA.

In the vertebrate retina and pineal gland, melatonin production displays diurnal variations with high levels at night. Hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4) catalyses the last step of melatonin biosynthesis. In the present study, a cDNA encoding chicken HIOMT was used to examine the effects of environmental lighting on HIOMT mRNA expression in the chicken retina. A day/night rhythm of HIOMT mRNA level was observed, with an average 5-fold increase during the night. Light strongly suppressed the night-time rise in HIOMT mRNA concentration while darkness prevented its daytime fall. An antibody directed against chicken HIOMT was used for immunocytochemical identification of retinal melatoninergic cells. HIOMT immunoreactivity could be observed in rods as well as in cones. However, the lowest levels of HIOMT immunoreactivity were always observed in the accessory cones of double cones. A few HIOMT-positive cell bodies could also be observed in the inner nuclear layer. Altogether, these data indicate that HIOMT gene expression in the retina is organized on a daily basis as a direct response to light, and that the different types of photoreceptors may not be equally involved in melatonin production.

Acetylserotonin O-Methyltransferase↗
PubMed1996

[Intraoperative and postoperative insertion control of anterior cruciate ligament-plasty. A radiologic measuring method (quadrant method)].

The best proximal insertion for an ACL graft is an anatomic insertion. The anatomic landmarks of this insertion area are well known, but it is sometimes difficult to find these anatomic landmarks during the operation. Thus, it is desirable to have an objective method to control the insertion. This study was undertaken because no description is available how you can localize the projection of the anatomic ALC insertion exactly in an X-ray picture. We dissected ten human cadaveric knees with intact ACLs. The most ventral, dorsal, distal and proximal borders of the insertion area were marked with 4 K-wires. The K-wires were shortened exactly on the bone border of the intercondylar space. Then the knees were X-rayed in a strictly lateral position. Thus, the shortened ends of the K-wires determined the projection of the ACL insertion in the X-ray picture. The center of this marked area was called point K. Then we determined 4 distances in the X-ray picture: distance t: the sagittal diameter of the lateral condyle, measured along the Blumensaat line distance h: the maximal height of the notch distance a: the distance between K and the dorsal border of the condyle, measured along t distance b: the distance between t and K, measured on a perpendicular line on t Distance a is a partial distance of t and distance b is a partial distance of h. Because of varying projection factors and varying knee sizes, absolute values of these distances are not helpful. This is the reason why we expressed a and b as a proportion of t and h. Distance a was measured 24.8% of distance t. Distance b was measured 28.5% of distance h. The maximal deviation of a and b was 2.2% and 2.5%. Therefore, you can say: In a strictly lateral X-ray picture the distance of K (midpoint of proximal ACL insertion) from the dorsal border of the condyle is 24.8% of the whole diameter of the condyle, and the distance of K from the roof of the notch is 28.5% of the notch-height. This method does not depend on the size of the knee and the distance between the X-ray unit and the knee. The only condition is that the X-ray of the knee must be strictly lateral. This method is easy to handle and is reproducible. It can be used intraoperatively if the surgeon is not sure about the right insertion or if the anatomic landmarks cannot be seen exactly. It can be used postoperatively for documentation of the right position of the substitute. It can be used to find out the possible reason for rupture of a transplant (insertion too ventral) before the revision operation.

Anterior Cruciate Ligament↗
PubMed1996

[Evaluation of CK-MB determination technique by immuno-enzymolfluorometry with Vidas (bioMérieux)].

The aim of this study was to evaluate a new automated fluorimetric enzyme immunoassay for CK-MB using the Vidas bioMérieux. The results for sera from 222 patients were compared with those obtained using two other methods of CK-MB determination in mass units (Stratus II Dade, Magic Lite Analyzer II Ciba Corning). Satisfactory results were obtained for within-run precision (CV < 9%) and between-run precision (CV < 10%) with medium (20 micrograms.L-1) and high (100 micrograms.L-1) concentrations of control sera. The method was linear in the range 1.7 micrograms.L-1 to 235 micrograms.L-1. Comparison with the two other techniques led to the following regression equations: y (Vidas) = 0.512 + 1.319 x (Stratus) [r = 0.991] and y (Vidas) = -0.15 + 0.795 x (Magic Lite) [r = 0.958]. The results obtained are highly correlated (p < 0.0001). The reference values were established on sera from healthy donors (n = 77). The Vidas technique gave analytical and clinical results similar to those of the other immunoenzymatic methods of CK-MB determination.

Creatine Kinase↗
PubMed1995

Human hydroxyindole-O-methyltransferase in pineal gland, retina and Y79 retinoblastoma cells.

Hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4) was studied in extracts of human pineal gland, retina and Y79 retinoblastoma cells. HIOMT enzyme activity and immunoreactive protein (approximately 42 kDa) were undetectable in the human retina; very low levels of HIOMT mRNA were detected using a highly sensitive RT-PCR/Southern blot method, as has been reported. Analysis of extracts of Y79 cells indicated that HIOMT enzyme activity, immunoreactivity (approximately 42 kDa) and mRNA (approximately 1.3 kb) were detectable at approximately 1/5-1/40 the levels found in the pineal gland. This unambiguously establishes that the HIOMT gene is expressed in Y79 cells. Kinetic analysis of Y79- and pineal-derived HIOMT indicates that the enzyme is generally similar in both tissues; one difference, however, is that substrate inhibition by N-acetylserotonin is greater with the Y79-derived enzyme. These studies show that Y79 cells represent a valid model to study the regulation of human HIOMT protein and mRNA; the differences detected may reflect the existence of tissue-specific regulatory mechanisms or differential patterns of expression of HIOMT isoforms.

Acetylserotonin O-Methyltransferase↗
PubMed1995

Anchoring of an immunogenic Plasmodium falciparum circumsporozoite protein on the surface of Dictyostelium discoideum.

The circumsporozoite protein (CSP), a major antigen of Plasmodium falciparum, was expressed in the slime mold Dictyostelium discoideum. Fusion of the parasite protein to a leader peptide derived from Dictyostelium contact site A was essential for expression. The natural parasite surface antigen, however, was not detected at the slime mold cell surface as expected but retained intracellularly. Removal of the last 23 amino acids resulted in secretion of CSP, suggesting that the C-terminal segment of the CSP, rather than an ectoplasmic domain, was responsible for retention. Cell surface expression was obtained when the CSP C-terminal segment was replaced by the D. discoideum contact site A glycosyl phosphatidylinositol anchor signal sequence. Mice were immunized with Dictyostelium cells harboring CSP at their surface. The raised antibodies recognized two different regions of the CSP. Anti-sporozoite titers of these sera were equivalent to anti-peptide titers detected by enzyme-linked immunosorbent assay. Thus, cell surface targeting of antigens can be obtained in Dictyostelium, generating sporozoite-like cells having potentials for vaccination, diagnostic tests, or basic studies involving parasite cell surface proteins.

Amino Acid Sequence↗
PubMed1995

Molecular mapping of wheat: major genes and rearrangements in homoeologous groups 4, 5, and 7.

A molecular-marker linkage map of hexaploid wheat (Triticum aestivum L. em. Thell) provides a framework for integration with teh classical genetic map and a record of the chromosomal rearrangements involved in the evolution of this crop species. We have constructed restriction fragment length polymorphism (RFLP) maps of the A-, B-, and D-genome chromosomes of homoeologous groups 4, 5, and 7 of wheat using 114 F7 lines from a synthetic X cultivated wheat cross and clones from 10 DNA libraries. Chromosomal breakpoints for known ancestral reciprocal translocations involving these chromosomes and for a known pericentric inversion on chromosome 4A were localized by linkage and aneuploid analysis. Known genes mapped include the major vernalization genes Vrn1 and Vrn3 on chromosome arms 5AL and 5DL, the red-coleoptile gene Rc1 on 7AS, and presumptively the leaf-rust (Puccinia recondita f.sp. tritici) resistance gene Lr34 on 7DS and the kernel-hardness gene Ha on 5DS. RFLP markers previously obtained for powdery-mildew (Blumeria graminis f.sp. tritici) resistance genes Pm2 and Pm1 were localized on chromosome arms 5DS and 7AL.

Chromosome Mapping↗
PubMed1995

T cell activation through Thy-1 is associated with the expression of a surface protein (p100) on a subset of CD4 cells.

Thy-1 molecules, which lack a transmembrane domain, can nonetheless induce T cell activation; it has thus been suggested that a separate transmembrane molecule associated with Thy-1 is required for signal transduction. We have previously characterized a transmembrane protein with an Mr of 100,000 (p100), which is non-covalently bound to two glycosyl-phosphatidylinositol (GPI)-linked molecules, Thy-1 and ThB. p100 is selectively expressed on the T cell surface and divides peripheral CD4 cells into two subpopulations. This differential expression on CD4 cells allowed us to investigate the role of p100 in signal transduction through Thy-1 molecules. Here we report that only p100+ CD4 cells proliferate and release cytokines in response to cross-linkage of Thy-1, although both p100+ and p100- CD4 cells strongly express Thy-1 on their surfaces. Control stimulation by anti-CD3 antibodies or concanavalin A induces identical thymidine uptake by the two CD4 cell populations. Interestingly, these two populations of CD4 cells had different cytokine release profiles after activation through CD3: only p100+ CD4 cells released high amounts of IL-2 and IFN-gamma, whereas both populations released IL-4. p100 expression correlates with the induction of homotypic aggregation of T cells after Thy-1 triggering. p100 is associated with kinase activity (fyn and lck), and phosphorylated proteins of 90, 59, 57 and 33 kDa co-precipitate with Thy-1 only in p100+ CD4 cells. Altogether, these data suggest that p100 is involved in signal transduction through Thy-1. p100 expression by activated CD4 cells in vivo may be relevant to the proposed function of Thy-1 as an accessory signaling molecule in cell activation.

Animals↗
PubMed1995

Mechanisms of intracellular pH regulation during postischemic reperfusion of diabetic rat hearts.

A marked decrease in the activity of the amiloride-sensitive Na+/H+ exchanger has been demonstrated in hearts from streptozotocin (STZ)-induced diabetic rats. The aim of this study was to investigate the contribution of other specific sarcolemmal transport mechanisms to intracellular pH (pHi) recovery upon reperfusion in STZ-induced diabetic rat hearts and their relation to recovery of ventricular function. Isovolumic rat hearts were submitted to a zero-flow ischemic period of 28 min at 37 degrees C and then reperfused for 28 min. The time course of pHi decline during ischemia and of recovery on reperfusion was followed by means of 31P-labeled NMR. The perfusion buffers used were either HEPES or CO2/HCO3-. An HCO3(-)-dependent (amiloride-insensitive) mechanism contributed to pHi recovery after ischemia in the diabetic rat hearts. Even when the Na+/H+ exchanger was blocked by amiloride in nominally HCO3(-)-free solution, a rapid rise in pHi occurred during the first 3 min of reperfusion. The early rise in pHi was reduced by external lactate and inhibited by alpha-cyano-4-hydroxycinnamate. This suggested that a coupled H(+)-lactate efflux may be a major mechanism for acid extrusion in the initial stage of reperfusion. The observation of a higher functional recovery on reperfusion in diabetic hearts is in accordance with previous studies using HCO3- buffer. However, this study shows that a good recovery of function occurred even more rapidly in diabetic hearts receiving HEPES-buffered solution than in those receiving HCO3(-)-buffered solution. This suggests that the HCO3(-)-dependent mechanism of regulation may be depressed in diabetic rat hearts.

Amiloride↗
PubMed1995

Multi-drug resistance (MDR) activity in acute leukemia determined by rhodamine 123 efflux assay.

We prospectively analyzed MDR functional activity by the Rh123 efflux assay in 84 de novo acute leukemias. Thirty of the 60 AML cases (50%) showed a positive dye efflux (in more than 10% of blast cells). In 19 cases, the dye efflux was superior to 30%. Twenty-four of the 30 efflux positive cases were CD34+ and could be studied in double staining. The mean percentage of effluxing CD34+ blast cells was 54%. There was a high correlation between CD34 expression and MDR activity (P < 10(-4)), MDR activity and PgP expression (P < 10(-6)). All the efflux negative samples were PgP negative. Nine efflux positive cases were PgP negative. Five of the 24 ALL were efflux positive. MDR activity did not correlate with FAB subtype (with the exception of AML3: 1/6 was efflux positive), age, white blood cell count or LDH level. Forty-seven AML patients were treated with conventional chemotherapy including cytarabine and an anthracycline. Thirty-one (66%) entered complete remission (CR). CR rate was statistically lower for efflux positive as compared to efflux negative patients, 46 vs 87% (P = 0.003), for PgP+ as compared to PgP- patients, 40 vs 78% (P = 0.01), for CD34+ as compared to CD34- patients, 45 vs 84% (P = 0.005). There was no correlation between P110 expression (32 AML cases studied) and FAB subtype, MDR status and clinical outcome. Two years survival was 20% for efflux positive patients as compared to 54% for efflux negative patients (P < 0.07), 15% for PgP+ vs 54% for PgP- patients (P < 0.04). The finding of efflux+/PgP- cases suggests the existence of other membrane efflux pumps. Rh123 efflux assay is straightforward in routine and could be included in MDR screening because of its potential interest in clinical outcome in AML.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

[Respective value of glycated hemoglobin and fructosamine assays in the care of diabetes mellitus].

The monitoring of metabolic balance in diabetes mellitus involves the assay of cumulative markers of protein glycation. Glycated hemoglobin, particularly the major component HbA1c, and fructosamine, which reflects glycated plasma protein levels, are the most commonly used parameters. Nevertheless, their utilization is still under discussion with respect to methodologies used, as well as to their respective interest in clinical diabetology. This review shows current opinion concerning the analytical and physiopathological use of these biological indicators.

Chromatography, Ion Exchange↗
PubMed1995

[Analysis of dot-blot technique for the detection of three autoantibodies (anti-Jo-1, anti-M2, anti-ribosome). Comparison with reference techniques].

A recently commercialized dot-blot (Cyto-Dot, BMD) offered a new method for the detection of three autoantibodies (Ab) anti-Jo-1, anti-M2, and anti-ribosomal protein although their only common point is the cytoplasmic localisation of their respective antigen. These Ab are detected by indirect immunofluorescence (IF) (anti-M2, anti-ribosomal protein), double immunodiffusion (ID) (anti-Jo-1) and western blotting (WB) (anti-M2). The aim of the study was to compare results obtained by the Cyto-Dot with those obtained by our reference technique. One hundred and seventy-seven sera were analysed, divided into four groups: group I (n = 15) with anti-Jo-1 Ab detected by ID, group II (n = 70) with anti-M2 Ab by WB, group III (n = 33) with anti-ribosomal protein Ab by IF (of which, 19 are precipitating by ID), group IV (control group, n = 59) with 31 sera of healthy individuals, six sera of patients with liver diseases resembling primary biliary cirrhosis and 22 with a particular serological profile. Cyto-Dot is very sensitive and specific for the detection of anti-Jo-1 Ab. Also, it represents a reliable method (sensitivity 0.99) for the screening of anti-M2 Ab and for the confirmation of an atypic immunofluorescence pattern. Equivalent to ID for the detection of anti-ribosomal protein Ab, the Cyto-Dot represents a good alternative technique. However, although this new diagnostic method represents a sensitive technique for the detection of the three auto-Ab, unfortunately, it can not be applied for large series.

Autoantibodies↗