Biomedical subjects

D Hayoz

Publications and source records attributed to D Hayoz.

100 records · Page 6Linked to original sources

PubMed1991

[Non invasive measurement of arterial compliance].

Pulse pressure waves are damped by the elastic properties of the blood vessels. This damping capacity can be evaluated by measuring vascular compliance a parameter which expresses changes of volume with respect to changes of pressure. Arterial compliance varies continuously with respect to intravascular pressure. Our group has developed an ultrasonograph which functions in the A mode capable of measuring the diameter of peripheral arteries during the cardiac cycle. This system is coupled to a photoplethysmograph which records non-invasively and continuously finger blood pressure. This enables construction of pressure-diameter graphs and the determination of arterial compliance and distensibility at each pressure value.

Arteries↗

PubMed1990

gp33-38, an early human T cell activation antigen.

We describe an activation Ag Me14/D12 that appears early after T cell activation and is absent in resting T lymphocytes. Me14/D12 is a nondisulfide-linked heterodimeric structure containing two polypeptide chains of 33,000 and 38,000 Da. The expression of Me14/D12 on resting T lymphocytes can be induced by different activation stimuli such as the lectins PHA and Con A, the phorbol ester PMA, and anti-CD3 mAb. The induction of mRNA for Me14/D12 (gp33-38) in PHA-activated T lymphocytes precedes that of IL-2R gene transcripts by more than 20 h. Me14/D12 mRNA was detectable as early as 2 h after the onset of activation and mRNA for the IL-2R only after 24 h. The surface expression of Me14/D12 was detectable between 12 and 24 h after activation and was maximal between 24 and 48 h. Several T leukemia cell lines express the Me14/D12 Ag. On Me14/D12- cell lines, PMA and IFN-gamma induced surface expression of Me14/D12. Once Me14/D12 Ag were expressed on Jurkat cells after stimulation with either PMA or IFN-gamma, the binding of mAb Me14/D12 induced the production of significant amounts of IL-2 and of Ca2+ mobilization from internal stores. Comparative biochemical studies clearly demonstrate that Me14/D12 (gp33-38) is different from the CD69 molecular complex defined by mAb MLR3 and AIM.

Antibodies, Monoclonal↗

PubMed1989

[Hairy cell leukemia: study of genomic rearrangements in splenic infiltration].

Genomic DNA extracted from heavily infiltrated spleens of 5 patients with hairy cell leukaemia was hybridized with genomic probes for immunoglobulin genes. The rearrangement pattern, correlating well with the immunohistochemical findings, was that of a clonal B-cell proliferation in all cases. Analysis of the lambda light chain genome with two different probes enabled more accurate localization of the clonal rearrangements within this genome. A small additional T-cell population identified in 3 cases was immunogenotypic of polyclonal (reactive) nature.

DNA Probes↗

PubMed1989

A novel interferon-gamma regulated human melanoma-associated antigen, gp33-38, defined by monoclonal antibody Me14-D12. II. Molecular cloning of a genomic probe.

The human Me14-D12 antigen is a cell surface glycoprotein regulated by interferon-gamma (IFN-gamma) on tumor cell lines of neuroectodermal origin. It consists of two non-convalently linked subunits with apparent mol. wt sizes of 33,000 and 38,000. Here we describe the molecular cloning of a genomic probe for the Me14-D12 gene using the gene transfer approach. Mouse Ltk- cells were stably cotransfected with human genomic DNA and the Herpes Simplex virus thymidine kinase (TK) gene. Primary and secondary transfectants expressing the Me14-D12 antigen were isolated after selection in HAT medium by repeated sorting on a fluorescence activated cell sorter (FACS). A recombinant phage harboring a 14.3 kb insert of human DNA was isolated from a genomic library made from a positive secondary transfectant cell line. A specific probe derived from the phage DNA insert allowed the identification of two mRNAs of 3.5 kb and 2.2 kb in primary and secondary L cell transfectants, as well as in human melanoma cell lines expressing the Me14-D12 antigen. The regulation of Me14-D12 antigen by INF-gamma was retained in the L cell transfectants and could be detected both at the level of protein and mRNA expression.

Antibodies, Monoclonal↗

PubMed1989

Polyclonal rearrangements of the T-cell receptor beta-chain in fatal angioimmunoblastic lymphadenopathy.

Genomic rearrangement of germline T-cell antigen receptor (TcR) and immunoglobulin (Ig) genes was studied by Southern blot analysis in seven patients with angioimmunoblastic lymphadenopathy (AILD). In three cases clinically suspected of transformation into malignant lymphoma, hybridization with the TcR beta probe showed markedly dimished intensity in the 11.5 kb germline band after Eco RI digestion and normal germline configuration after Hind III and Bam HI digestion, indicating polyclonal T cell rearrangements. A clonal rearrangement of the TcR beta gene was detected in only one case at initial biopsy. No monoclonal rearrangement of Ig genes was observed. These data show that in some cases of AILD disease progression is indicated by polyclonal TcR rearrangements and not by outgrowth of a malignant clone, supporting the concept of AILD as an immunoregulatory disorder.

Blotting, Southern↗

PubMed1989

Multipoint linkage mapping of the Xq25-q26 region in a family affected by the X-linked lymphoproliferative syndrome.

We have performed, in a large Swiss family, a study of linkage between various DNA markers in the Xq24-27 region and the locus for the X-linked lymphoproliferative syndrome (XLP). Our results indicated that the marker DXS37 in Xq25-q26 is genetically linked to the XLP syndrome. The multipoint linkage analysis showed that the disease locus is distal to DXS11, but proximal to the hypoxanthine phosphoribosyl-transferase gene (HPRT).

Female↗

PubMed1988

X-linked lymphoproliferative syndrome. Identification of a large family in Switzerland.

Observation of a patient with acquired hypogammaglobulinemia associated with a mononucleosis syndrome led to the identification of one of the largest families affected by the X-linked lymphoproliferative (XLP) syndrome in the world. It is the first such family identified in Switzerland and the largest in Europe. At least nine male subjects over two generations presented phenotypic expressions consistent with the XLP syndrome. Study of the pedigree extending over seven generations suggests that the mutation occurred in the proband's great-grandmother. In the next generation, a second mutation of the X chromosome in one branch of the family resulted in expression of hemophilia A in the children. This remarkably large family, comprising six living obligate female carriers, displays a wide spectrum of the XLP syndrome and offers valuable information for future genetic linkage studies and for genetic counseling.

Adult↗

PubMedDate not supplied

Morphometric analysis of heparin coated versus standard intra-aortic balloons.

The adverse effects of systemic heparin administration has led to the development of heparin coated devices. Intra-aortic balloons are frequently used in clinical settings in which complications of systemic heparin, especially bleeding, are feared. The current study evaluated the thromboresistance of heparin coated intra-aortic balloons. Six bovine calves were chosen for the experiment. In each animal, three intra-aortic balloons were inserted, and set to the automatic mode: two in the vena cava for 15 min and 45 min, respectively, and one in the aorta for 6 hr. There were nine standard and nine heparin coated intra-aortic balloons. At the end of the procedures, three samples of each intra-aortic balloon were analyzed with scanning electron microscopy for computed analysis of the balloon surface covered with fibrin and cells. The scanning electron microscopy analysis showed no deposit at any time interval on the heparin coated sample surfaces, whereas 3.6% +/- 9.2% (mean +/- SD) of the standard sample surfaces were covered with deposits at 15 min (p = 0.06), 14.8% +/- 24.3% at 45 min (p = 0.01), and 4.4% +/- 12.4% at 6 hr (p = 0.06). Strikingly, none of the 27 heparin coated samples showed any microscopic deposits, whereas 11 of the 27 standard samples did (p < 0.002). Heparin coated intra-aortic balloons appear to be a promising strategy, especially for patients with absolute or relative contraindications to systemic heparinization.

Animals↗

PubMedDate not supplied

Cloning of an interferon-gamma regulated human melanoma-associated antigen: identity to the intercellular adhesion molecule ICAM-1.

The human melanoma-associated antigen identified by the monoclonal antibody (mAb) Me14-D12 is a cell surface protein whose expression is induced by interferon-gamma (IFN-gamma). We have recently reported the molecular cloning of a genomic probe specific for the gene and mRNA of this protein. By screening with the genomic probe, we have now isolated a full length 3.0 kb cDNA from a Raji cell line-derived lambda-gt10 library. Sequence analysis of this cDNA showed a 99.8% homology with the intercellular adhesion molecule-1 (ICAM-1). Mouse Ltk- cells stably transfected with the human cDNA clone were found to express the ICAM-1 antigenic determinants detected by mAb Me14-D12 and a reference anti-ICAM-1 mAb, as judged by surface immunofluorescence. Immunoprecipitation of surface-iodinated proteins with mAb Me14-D12 revealed the presence of a 90 kD molecule with identical mobility to ICAM-1. In addition, mAb Me14-D12 could inhibit the phorbolester-stimulated aggregation of U937 cells. The findings show that the human melanoma-associated Me14-D12 antigen is the adhesion molecule ICAM-1.

Antibodies, Monoclonal↗

PubMedDate not supplied

Intraluminal pressure modulates the magnitude and the frequency of induced vasomotion in rat arteries.

Arterial vasomotion and its relation to intraluminal pressure were investigated in vitro in isolated rat arteries. Femoral arteries (mean diameter = 768.2 +/- 25 microns, n = 5) and mesenteric arteries (mean diameter = 393.4 +/- 32 microns, n = 5) were used in this study. Arterial segments were excised, mounted on microcannulas and perfused with Tyrode's solution at a constant flow (100 microliters/min). After equilibration, intraluminal pressure was stepwise changed from 0 to 120 mm Hg. The changes in the outer diameter of the vessels were measured continuously over a period of 4 h after the equilibration. Vasomotion was induced by constrictor agonists (norepinephrine 10(-6) M for mesenteric arteries and norepinephrine 10(-6) M + Bay K8644 10(-7) M for femoral arteries) and was maintained only in the presence of the above-mentioned drugs. Both vasomotion magnitude and frequency are modulated by pressure. Vasomotion frequency increases with pressure increase. When intraluminal pressure varied between 0 and 120 mm Hg, vasomotion frequency varied between 0.19 and 0.49 Hz for mesenteric arteries and between 0.04 and 0.23 Hz for femoral arteries. Thus, vasomotion frequency differed clearly between the two vessel types. Vasomotion amplitude shows a biphasic relationship with a maximum occurring at about 40 mm Hg for mesenteric arteries and 50 mm Hg for femoral arteries. Based on these findings, it is hypothesized that vasomotion amplitude relates to the active mechanical properties of the artery and, in particular, to its contractile capacity.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗