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Biomedical subjects

M C Bourdillon

Publications and source records attributed to M C Bourdillon.

At least 37 records · Page 2Linked to original sources
PubMed1981

Selection of a strain of rats with spontaneous high cholesterolemia.

By means of an inbred selection procedure utilizing positive assortative mating, high (SHC: spontaneous high cholesterolemic) and low (SLC: spontaneous low cholesterolemic) blood cholesterol strains of rats were developed. This procedure was shown to be much more efficient in increasing than in lowering the blood cholesterol level. The diet used throughout selection was normal laboratory chow; therefore the high and low blood cholesterol levels occurred spontaneously. Since the 6th generation there has been no overlap between the blood cholesterol values of the animals of the two strains. The cholesterol increase with ageing was found to be strongly related to sex, but weakly to the genes governing the differences between SHC and SLC rats. Cholesterol enhancement following a hyperlipidic diet did not differ between strains or sexes. It appears that the SHC rat strain could be an interesting model, particularly in pharmacological research.

Aging↗
PubMed1981

[Tricuspid valve replacement by Hancock's prosthesis].

The medium term results of tricuspid valve replacement with the Hancock bioprosthesis are reported. Twenty eight patients underwent tricuspid valve replacement with this prosthesis between December 1974 and January 1978: mitral valve replacement with a Starr-Edwards or Cooley-Cutter prosthesis was associated in all cases and aortic valve replacement with a Björk-Shiley prosthesis in 11 cases. Follow-up at an average of 36,2 months after operation examined functional status, cardiac size and haemodynamics (in 12 patients). Three patients died in the immediate postoperative period and four others died later: the number of survivors was greater in the triple valve replacement (9/11) than in the double valve replacement group (12/17) but the difference was not statistically significant. Of the 23 surviving patients (average follow-up of 36,2 +/- 9,6 months), 17 were classified in functional Classes I or II of the NYHA classification. All patients had been Class III or IV before operation. The cardiothoracic ratio did not decrease significantly in patients undergoing triple valve replacement. Control cardiac catheterisation showed a significant increase in cardiac index (2,53 +/- 0,11 1/mn/m2, compared to 1,87 +/- 0,35 1/mn/m2 before operation; p less than 0,001) without significant reduction in pulmonary artery or right atrial pressures. The resting gradient across the Hancock bioprosthesis was not related to the size of the prosthesis (No 29-30: 2,17 +/- 2,57 mm Hg; No 31-33: 2,78 +/- 3,53 mm Hg) or with the quality of the functional result. However, on exercise, the gradient across the prosthesis was high, reaching an average of 10,3 +/- 5,2 mm Hg). The operative mortality of tricuspid valve replacement is relatively bioprosthesis associated with mitral and/or aortic valve replacement is relatively bioprosthesis associated with mitral and/or aortic valve replacement is relatively low (about 10%) and could be an argument in favour of broadening the indications for tricuspid valve replacement as resting tricuspid function with a bioprosthesis is satisfactory. However, the stenotic effects on exercise and the uncertainty over the long-term outcome of bioprostheses suggest that surgery should be limited to severe tricuspid stenoses and/or major tricuspid regurgitation organic or functional uncontrolled by digitalis and diuretic therapy.

Adult↗
PubMed1980

Variations in growth and cell cycle time of arterial smooth muscle cells cultured at low density.

The population kinetics of cultured rat arterial smooth muscle cells replated at various low densities were studied by direct counting and observation of the cells. Population doubling time decreases with increasing initial density of the culture. These variations in population doubling times depend on both the variation in the percentage of quiescent cells and on the variation of the mean cell cycle time of non-quiescent cells.

Animals↗
PubMed1979

[Morphological and histochemical behavior of arterial tissue in normal and spontaneously hypo- or hypercholesterolemic rats on a normal or hyperlipidic diet].

Hypo and hypercholesterolemic rats strains were selected (Lyon) and compared to a normocholesterolemic one issued from the same race (Sprague-Dawley). The arterial tissue of these three strains at three ages (10-19-25 months) and their reactivity to an hyperlipidic diet (2 and 6 month duration) were studied using histological and histochemical technics. There were neither histological nor histochemical differences between the three strains whatever the ages. Therefore, at the present stage of selection, the genetic differences have not changed the arterial metabolism or its evolution during ageing. However the arterial reactivity of hypo and hypercholesterolemic strains towards an hyperlipidic diet was different: indeed both strains developed hypercholesterolemia, liver steatosis and diffuse intimal lipoidosis, but on the other hand the hypercholesterolemic rat alone demonstrated arterial cell proliferation. These data suggest that a same genetic trait can give rise to both a spontaneous hypercholesterolemia and an arterial hyperactivity against a superimposed hyperlipemia.

Animals↗
PubMed1977

Proliferation of primary cultures from rat aortic media. Effects of hyperlipemic serum.

Tissue cultures have been made from explants of thoracic aortas to study the growth pattern of rat aortic mediacytes. Three parameters were measured weekly: the surface of the culture, the relative increase of this surface and the number of 3H-thymidine labelled cells per unit surface. The primary cultures showed two distinctive phases: a first phase with continuous growth followed by a plateau phase. We studied the growth effect of homologous hypercholesterolemic serum added to the cultures. The cell proliferation was affected by the cholesterol level in the medium and the stage of the culture at which serum incubation was initiated. An enhancing effect occurred in the rat resistant to such treatment in vivo.

Animals↗
PubMed1976

Primary cultures of rat aortic media: a growth stop phenomenon different from contact inhibition.

Cultures have been made from explants of thoracic aortas to study the growth pattern of aortic mediacytes. Explants from aortas of eight rats, aged between seven to eight weeks, were seeded. Three parameters were measured weekly from the second to the nineth week: the surface of the culture (S); the relative increment of this surface (delta S/S) and the number of 3H-thymidine labelled cells by the unit surface (n chi S-1) after autoradiography. The surface of primary culture, in relation to time, has roughly the shape of a sigmoidal curve. Growth is continuous until the fifth week and reaches a plateau beyond that time. The two other parameters decreased regularly during the first phase to attain a minimum at the beginning of the plateau-period; however new cells in the S-phase are still found in this second period.

Animals↗
PubMed1976

Histological arguments for collagen and elastin synthesis by primary cultures of rat aortic media cells.

Using the histological staining methods of Weigert and of Masson on primary cultures of rat aortic media cells, we obtained additional proofs of the smooth muscle cell's ability to secrete collagen and elastin in vitro: the percentage of positive flasks with aorta rings was the same throughout the follow-up, but increased gradually for the new tissue growing around the rings.

Animals↗
PubMed1976

[Formation of xanthomatous cells in vitro from the aortic media of the rat].

The foam cell is viewed as a specific component of the atherosclerotic plaque found in human or experimentally induced in the animal. A study using light microscopy (staining with Sudan III) and electron microscopy was performed on cell cultures derived from rat aortic media. Sudanophilic and electron transparent vacuoles were observed in vitro in 11 week cultures. The sudanophilic cells were either scattered or crowded in clusters; some of them were found in a mitotic phase. Different serums were applied to the cultures starting from the 6th week: either calf serum (continuing the previous treatment), or normocholesterolemic rat serum (NCRS) or hypercholesterolemic rat serum (HCRS). Sudanophilic cells were observed more frequently in the cultures on exposure to HCRS than to NCRS (p less than 0.05). Thus it was possible to induce the formation of foam cells in vitro in cultures of arterial tissue derived from the rat, which is known to be resistant to atherosclerosis.

Animals↗