Biomedical subjects

F Cormier

Publications and source records attributed to F Cormier.

At least 55 records · Page 3Linked to original sources

PubMed1992

Intravascular ultrasound guided holmium:YAG laser recanalization of occluded arteries.

Current angioplasty devices are limited by arterial wall dissection and perforation, and by early recurrence from inadequate debulking of lesions. This study evaluated intravascular ultrasound (IVUS) as guidance for concentric laser recanalization of arterial occlusions. Twelve, 2-4-cm-long canine iliac artery occlusions were treated at 2 weeks (organizing thrombus) to 12 weeks (firm fibrous lesions) using a Holmium:YAG laser (2,100 nm wavelength) in free running mode, FRM, (250 musec pulse, 5 Hz), n = 9; and Q-switched mode, QSM (200 ns pulse, 6 Hz), n = 3. A 200 microns (n = 2) or 600 microns (n = 10) optic fiber was centered in the artery coaxial to a 5Fr rotating A scan IVUS probe. The fiber was positioned in the center of the artery distal to the lesion and slowly advanced through the obstruction. In 8 occlusions the same fiber was used as a guidewire for passage of either a 1.6-mm-(n = 2) and/or 3.0-mm (n = 6) diameter multifiber catheter (19 x 100 and 19 x 200 microns fibers, respectively) using FRM energy to further debulk the lesion. In all cases, IVUS guidance enabled concentric initial recanalization of occlusions, although 3 vessel perforations resulted from fiber deviation off the center of the lumen at a distance of 2 to 4 cm from the IVUS imaging element. Both QSM and FRM modes ablated tissue, with FRM modes producing more tissue fragmentation and thermal effect. IVUS images accurately diagnosed the location of lesions compared to angioscopic views and pathologic analysis of the specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Laser↗

PubMed1992

BEN, a novel surface molecule of the immunoglobulin superfamily on avian hemopoietic progenitor cells shared with neural cells.

BEN is a novel molecule of the immunoglobulin superfamily that we previously identified by means of a monoclonal antibody on neural cell populations during avian development and epithelial cells of the bursa of Fabricius. In this paper, we describe the expression of BEN by hemopoietic cells during ontogeny. In the thymus, BEN is expressed as early as E9, and from E12 until just after hatching 30-60% of thymocytes are BEN positive. Thus the cells expressing BEN are immature thymocytes and not yet differentiated T cells. In the spleen, BEN expression parallels the myelopoietic activity. It is present on 75% of splenocytes during embryonic development and falls rapidly to 20% of cells during the first week after hatching when the spleen is becoming a secondary lymphoid organ. BEN is also found on a large proportion (about 80% positive cells) of bone marrow cells during ontogeny. Post hatching, BEN is present on 40-50% of bone marrow cells. The population of BEN-positive cells in the bone marrow includes myeloid and erythroid progenitor cells, identified by their ability to form colonies in vitro. BEN expression is lost as progenitor cells proliferate and differentiate to develop mature colonies in the clonal assay. Mature myeloid cells, such as macrophages, granulocytes, thrombocytes, and erythrocytes do not express the BEN antigen. Taken together, these data demonstrated that BEN is a stage-specific rather than a lineage-specific differentiation antigen expressed by immature hemopoietic cells.

Activated-Leukocyte Cell Adhesion Molecule↗

PubMed1992

Dissecting aneurysms of the main trunk of the superior mesenteric artery.

We treated four symptomatic patients who were admitted with a spontaneous and isolated dissecting aneurysm of the superior mesenteric artery. All four patients underwent operation. The superior mesenteric artery was repaired by means of either a bypass graft in two cases or an endoaneurysmorraphy in the latter two cases. Complete symptomatic relief with no postoperative complications was achieved in every case. The arterial repairs remained patent, and the patients remained free of symptoms, with follow-up ranging from 6 to 47 months. The available literature on this unusual lesion is reviewed.

Adult↗

PubMed1991

Developmental kinetics of hemopoietic progenitors in the avian embryo spleen.

By means of plasma clot clonal cultures, the content of the avian spleen in granulomonocytic progenitors was studied during ontogeny. Serum-free media were used that were supplemented with growth activities produced either by embryonic fibroblasts or adult spleen cells. These two conditioned media not only permitted the growth of M-CFC, G-CFC, and GM-CFC but also F-CFU (fibroblast colony-forming units) from quail or chick embryonic spleen cells. The presence of spleen cell-conditioned medium promoted the development of large colonies of immature granulocytes. In the chick the first hemopoietic progenitors appeared at E9 and their number displayed two peaks, one at E15 and a smaller one at E18. In the quail the first progenitors were detected as early as E7 and their number peaked at E10. In this species, hemopoietic progenitors disappeared definitively before hatching while in the chick some were still present at P3. The progenitor content of the chick embryo spleen was compared to that of the bone marrow. This content remained stable during all of embryonic life, while the bone marrow exhibited a very different profile, where a sharp peak at E16 was followed by an acute decline and a stabilization at a rather low level. The particular profile in the spleen speaks in favor of a special role of this organ in the development of the hemopoietic system.

Animals↗

PubMed1991

A new technique for intraluminal hollow organ imaging: three-dimensional ultrasound.

Intraluminal ultrasound (ILUS) is a new catheter-based system which produces two-dimensional (2D), cross-sectional images of tubular structures. The principle of image acquisition using 5.0 Fr (30 MHz) and 8.0 Fr (20 MHz) ILUS catheters containing ultrasound transducers at the tip, is equally applicable to all tubular or hollow organs. This article illustrates the feasibility of intraluminal imaging of hollow organ structures, and describes computerized three-dimensional (3D) reconstruction of the 2D images, using a PC-based image analysis system. A set (n = 90) of longitudinally aligned, consecutive 2D images was sampled from various organs (canine bladder, urethra, jejunum, esophagus, and trachea) and computer processed to produce 3D images. By adjusting image density threshold and viewing angle, the lumen and wall morphology can be examined in any projection. Possible applications include diagnosis of lumen encroaching pathology, guidance of intraluminal instruments, and assessment of the effects of endoluminal interventions.

Animals↗

PubMed1991

Serum-free culture of enriched murine haemopoietic stem cells. I: Effect of haemopoietic growth factors on proliferation.

Using a population of cells highly enriched for multipotential day 12 spleen colony forming cells (CFU-S) (termed the FACS-BM population), and a serum-free culture system, the requirements for development of multipotential cell have been investigated and compared to previous results using serum containing cultures. In both serum-free and serum supplemented cultures interleukin-3 (IL-3) was a potent colony stimulating factor, although it was more effective in serum free conditions. However, colony stimulation by granulocyte-macrophage colony stimulating factor (GM-CSF) and macrophage-colony stimulating factor (M-CSF) was markedly reduced in the absence of serum. Significantly, the ability of interleukin-1 (IL-1) and granulocyte-colony stimulating factor (G-CSF) to synergise with these two growth factors was retained in serum-free conditions, indicating that these growth factors act directly on the FACS-BM without serum co-factors. Furthermore synergistic interactions between IL-3 plus IL-1, and IL-3 plus M-CSF were only manifest in serum-free conditions. The significance of these results in relation to the ability of these growth factors to act directly on multipotential cells is discussed.

Animals↗

PubMed1991

Serum-free culture of enriched murine haemopoietic stem cells. II: Effects of growth factors and haemin on development.

A serum-free culture system was used to determine the effects of growth factors on the clonogenic development of a population of cells highly enriched for multipotential day 12 spleen colony forming cells (CFU-S) (FACS-BM). Under these conditions, interleukin-3 (IL-3) was found to be primarily a proliferative stimulus, the progenitor cells developing in the clonal assay systems produced colonies of morphologically undifferentiated cells for up to 20 days. No such induction of proliferation without maturation was observed with other growth factors (eg. granulocyte-macrophage colony stimulating factor (GM-CSF)). However, combinations of IL-3 plus secondary growth factors such as GM-CSF, macrophage colony stimulating factor (M-CSF), granulocyte colony-stimulating factor (G-CSF) or interleukin-1 (IL-1) led to the formation of colonies containing mature haemopoietic cells of the granulocytic, megakaryocytic or monocytic lineages. In contrast, erythroid development did not occur unless the protoporphyrin, haemin, was added to the cultures. Under these conditions mature erythroid cells were produced in cultures containing either IL-3 or GM-CSF (with or without erythropoietin (epo)). In replating experiments it was determined that the FACS-BM cells were able to generate large numbers of clonogenic cells for up to 30-40 free cultures. Such cultures, therefore, may be useful for investigating the biological and basis of the generation of clonogenic cells and of haemopoietic cell differentiation and development in response to growth factors.

Animals↗

PubMed1990

Long-term cultures of chicken bone marrow cells.

We report an adaptation to cultures of chicken bone marrow cells of the Dexter culture technique for obtaining long-term hemopoiesis in vitro. Cells were seeded in DMEM supplemented with fetal calf serum (20%) and hydrocortisone (10(-6) M) with or without chicken serum (1%). Cultures were incubated at 37 degrees C and fed every 2 weeks. An adherent cell layer composed of macrophages, fibroblasts, and adipocytes became established, over which hemopoietic cells formed foci and were released into the supernatant. Granulocytes and monocytes-macrophages differentiated in a constant proportion until Week 6, whereafter differentiation became progressively restricted to the monocytic lineage. As demonstrated by the generation of colony-forming cells, hemopoiesis was maintained for either 12 or 28 weeks.

Animals↗

PubMed1989

Long-term results of aortoinnominate and aortocarotid polytetrafluoroethylene bypass grafting for atherosclerotic lesions.

Between January 1978 and December 1986, 69 polytetrafluoroethylene bypass grafts on the ascending aorta were placed in 53 patients with atherosclerotic occlusive disease of the innominate and left common carotid arteries. Thirty-six patients had symptoms predominantly of amaurosis fugax, verebrobasilar ischemia, and upper limb ischemia. The remaining 17 patients had no symptoms but had severe hemodynamically significant occlusive disease. All operations were accomplished via median sternotomy. One patient died after surgery (operative mortality rate 1.9%), and one patient had minor postoperative neurologic deficit that partially improved on long-term follow-up. Patency of the reconstruction was routinely assessed by a Doppler device combining (1) a continuous wave Doppler and (2) real-time mechanical sector B-mode imaging with frequencies of 3.5 MHz and 7.5 MHz. There were two early asymptomatic occlusions; one was related to a technical error that was successfully revised and the other to low systemic perfusion. The mean follow-up time was 50.5 months. Two patients were lost to follow-up and a further six patients died, for a cumulative 5-year survival rate of 84.9%. One patient had only partial improvement in symptoms and one patient sustained a late postoperative neurologic deficit after internal carotid occlusion distal to a patent aortocarotid bypass. The remaining patients were free of symptoms. There were no infective complications. All the patients underwent late assessment by Doppler ultrasonography and B-mode scanning. One asymptomatic occlusion was thereby identified to be a result of diminished runoff. The overall secondary patency rate at 5 years was 96.1%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

The wall of the chick embryo aorta harbours M-CFC, G-CFC, GM-CFC and BFU-E.

In the 3- to 4-day avian embryo, after the first wave of haemopoiesis which derives in the yolk sac from haemopoietic stem cells formed in situ, haemopoietic cells emerge in an intraembryonic site, the wall of the aorta. In this paper, we demonstrate that this site harbours M-CFC, G-CFC, GM-CFC and late and early BFU-E. In serum-free medium, the growth of M-CFC and GM-CFC was strictly dependent on CSF present in fibroblast-conditioned medium (FCM). The growth of G-CFC was improved when FCM was replaced by a minute quantity of chicken and fetal calf serum. Like erythroid progenitors from bone marrow, BFU-E detected here required anaemic chicken serum to differentiate into haemoglobinized cells. The frequency of the different types of haemopoietic progenitors in the aortic population was very high: 80 M-CFC, 25 G-CFC, 4 GM-CFC and 70 BFU-E for 12,500 aorta cells, i.e. two to eight times more frequent than in the bone marrow population, depending on the type of progenitors.

Animals↗

PubMed1988

Early haemopoietic stem cells in the avian embryo.

Using 'yolk sac chimaeras', we have previously demonstrated that stem cells, destined to colonize haemopoietic organs other than the yolk sac, arise in the embryo proper. We have now investigated the emergence and potentialities of these cells in vivo and in vitro. The in vivo approach consisted of interspecies grafting between quail and chick embryos. The cell progeny from the grafts was detected by means of QH1, a monoclonal antibody specific for the quail haemangioblastic lineage. When grafted into the dorsal mesentery of the chick embryo, which is a haemopoietic microenvironment, the region of the aorta from E3-E4 quail embryos generated large haemopoietic foci. When associated with a chick attractive thymic rudiment, cells left the quail aorta, entered this rudiment and underwent lymphopoiesis. Cell suspensions prepared from 40-50 chick aortae, seeded in appropriate semi-solid media, yielded macrophage, granulocyte or erythrocyte clones. These colony forming cells were two to eight times more frequent than in cell preparations from hatchling bone marrow. By contrast, cells prepared from the whole embryonic body deprived of the aorta were not clonogenic. By interspecies grafting of somatopleural (ectoderm + mesoderm, e.g. limb bud) or splanchnopleural rudiments (endoderm + mesoderm, e.g. lung, pancreas, intestine), the endothelial lining of blood vessels was shown to arise by two entirely different processes according to the rudiment considered: angiogenesis, i.e. invasion by extrinsic endothelial cells, in the limb bud, and vasculogenesis, i.e. in situ emergence of endothelial cells, in internal organs. The spleen, which first develops as a continuum to the pancreatic mesoderm, acquires its endothelial network by vasculogenesis, and is colonized by extrinsic haemopoietic stem cells. Granulopoietic cells in the pancreas and accessory cells in the lung are also extrinsic. Thus, in the case of endomesodermal rudiments, interspecies grafting reveals separate origins of endothelial and haemopoietic cells.

Animals↗

PubMed1987

Polytetrafluoroethylene bypass for revascularization of the atherosclerotic internal carotid artery: late results.

Between 1979 and 1986, 60 patients underwent a total of 62 revascularizations of the internal carotid artery with an expanded polytetrafluoroethylene (ePTFE) bypass. In 54 cases, the indication for surgery was the presence of extensive lesions in both the internal and common carotid arteries and, in 8 cases, a late complication of a previous surgical procedure. There were no early postoperative deaths (within 30 days). Three patients (5%) experienced postoperative neurologic complications. Two complications resolved completely whereas one left minimal residua. The bypasses remained patent in all three cases. All patients had early postoperative Doppler B-mode ultrasonography. Two early occlusions (3.2%) were disclosed but the patients remained symptom-free. Four neurologic complications were observed over long-term (average 23 months) follow-up. None were related to the operated carotid artery. There were no cases of infection or late occlusion. No hemodynamic or morphologic anomalies were observed on late follow-up ultrasound studies. These favorable results support the use of ePTFE as a reliable substitute when adequate autologous saphenous vein is not available for carotid bypass. Routine utilization might be indicated in cases of long bypasses, especially when it is necessary to implant the bypass on the ascending aorta, or when the proximal site of implantation is made on a thickened arterial wall.

Aged↗

PubMed1986

Serum-free culture of primitive murine hemopoietic colony-forming cells.

We report the effect of four sources of hemopoietic growth factors, alone or in combination, on colony growth in serum-free cultures of bone marrow from normal mice or marrow from mice pre-treated with 5-fluorouracil (5-FU-bm). The four supplements were: mouse spleen conditioned medium (SCM, a source of multi-lineage colony-stimulating activity, multi-CSA), human placental conditioned medium (HPCM, a source of synergistic activity), pregnant mouse uterus extract (PMUE, a source of M-CSA) and erythropoietin (Epo). First, in cultures of normal marrow, only PMUE and SCM induced significant colony growth when added alone. The majority of those colonies contained granulocytes and macrophages (myeloid colonies). In Epo-supplemented cultures, only SCM supported the growth of erythroid bursts and mixed erythroid-myeloid colonies. HPCM thus appears to be a poor source of multi-CSA. Second, in cultures of 5-FU-bm, few colonies developed if any of the above supplements were added alone. Only SCM + Epo together stimulated the formation of a low number of very large, mixed erythroid/myeloid/megakaryocyte colonies. HPCM, but not SCM, synergized with PMUE to augment myeloid colony numbers. Hence, SCM appears to be a poor source of synergistic activity (SA). In cultures of 5-FU-bm already supplemented with HPCM + PMUE, the addition of Epo did not change total colony numbers but did induce erythroid differentiation in one third of the colonies present. These data suggest that multi-CSA and SA may be expressed by different factors and that 5-FU pre-treated marrow contains: a population of primitive multipotential progenitors which form large, mixed colonies in the presence of SCM + Epo, and a larger Epo-sensitive population which also requires HPCM + PMUE to form mixed colonies.

Animals↗

PubMed1986

In vitro detection of cells with monocytic potentiality in the wall of the chick embryo aorta.

Our previous investigations in 3- to 4-day avian chimeras have revealed that the wall of the aorta is a site from which hemopoietic stem cells can be obtained. In the present work using an in vitro clonal assay, we searched for cells with monocytic potentiality in this location as well as in the remainder of the embryo's body. In each experimental series thoracic segments from 30 chick embryo aortae were dissociated by a pancreatin treatment and plated in agar medium containing chicken serum and fibroblast-conditioned medium. Eighty to 620 macrophage colonies developed when 50,000 cells from 4-day aortae were plated, somewhat fewer when 3-day cells were plated (19-110). By contrast no progenitors were detected when cells were plated from 3- or 4-day embryos after their aorta had been removed. The cell composition and morphology of colonies deriving from aorta cells, their growth requirement and kinetics of development were identical to these of colonies deriving from young chicken bone marrow cells, cultured in the same conditions. The presence of macrophage progenitors in the wall of the 3- or 4-day embryo aorta and their absence in the rest of the embryo argues for a specific role of that region in embryonic hemopoiesis, namely that this is the location where intraembryonic hemopoietic stem cells emerge from the mesoderm at that period of development.

Age Factors↗

PubMed1986

Persistant carotido-hypoglossal artery associated with atherosclerotic stenosis treated by venous bypass.

A 66 year-old woman presented with a tight but asymptomatic atheromatous stenosis in a persistant carotido-hypoglossal artery. Stenosis was documented by ultrasound Doppler tomography whereas the embryologic anomaly was disclosed by digital angiography. A successful venous bypass was done. Based on this case report, the diagnostic and therapeutic problems raised by such anomalies are discussed.

Blood Vessel Prosthesis↗

PubMed1985

Complete replacement of serum in cultures of murine primitive erythroid and multipotential progenitor cells: absolute requirement for spleen conditioned medium.

We describe a serum-free medium for the formation of erythropoietic bursts by murine bone marrow cells. Iscove's modified Dulbecco's medium supplemented with bovine serum albumin, iron-saturated transferrin, soybean phospholipids and cholesterol supported burst formation. The further addition of hemin increased burst numbers to above those obtained in serum-containing cultures. With or without hemin, a source of burst-promoting activity (BPA) (crude or partially purified spleen conditioned medium) and erythropoietin were essential. This system provides a sensitive assay for BPA. Of all colonies developing in these cultures, 16% were pure erythroid, 17% mixed erythroid/myeloid, 36% macrophage, 19% macrophage/basophil and macrophage/neutrophil, 9% basophil and 2% neutrophil.

Animals↗

PubMed1985

Functional capacities of chick embryo thymocytes in the mixed lymphocyte reaction.

Thymocytes from chick embryos homozygous for the B19 haplotype of the major histocompatibility locus were tested in a one way MLR either as responder or stimulator cells, against adult peripheral blood lymphocytes from B14/14 or B19/19 strains. 13-day embryonic thymocytes were strongly stimulated by adult allogeneic PBL. By contrast 16-day thymocytes were unresponsive. This difference might be related to the rhythmic waves of stem cell entry and multiplication which characterize the ontogeny of the avian thymus. Mitomycin-treated thymocytes from 13-day or 16-day embryos were both efficient in stimulating thymidine uptake by adult allogeneic PBL.

Animals↗

PubMed1984

Aging of cylinders excised from pulp tissues of the ;golden delicious' apple.

Aging cylinders excised from ;Golden Delicious' apple (Pyrus malus L.) pulp, like the intact fruit, exhibit some characteristic phenomena such as rise in respiration (climacteric), ethylene synthesis, enzymic changes, and increase in ribosomes and mRNA. Aging of cylinders of pulp tissues may offer a useful physiological tool for the study of maturation and senescence.

Journal Article↗