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B Boilly

Publications and source records attributed to B Boilly.

69 records · Page 4Linked to original sources
PubMed1987

Stimulation in cell culture of mesenchymal cells of newt limb blastemas by EDGF I or II (basic or acidic FGF).

After amputation of a newt limb, a blastema forms on the amputation plane and later differentiates to regenerate all the missing parts of the limb. Proliferation of blastema cells is under the control of severed nerves which deliver a 'neurotrophic factor' (NTF) of unknown nature. In order to characterize this factor we use a primary culture of blastema mesenchymal cells; changes in mitotic index after 48-h colchicine treatment indicate mitogenic activity of potential growth substances. These cells, which are stimulated by nerve extracts (mitotic index X 6), were tested with two purified growth factors extracted from bovine retina or brain (EDGF I = basic FGF and EDGF II = acidic FGF). We show that these two growth factors stimulate proliferation of blastema cell cultures in a dose-dependent manner. Maximal stimulation was obtained at 3 pM for EDGF I (mitotic index X 5.7) or 300 pM for EDGF II (mitotic index X 4.9). So it appears that these two growth factors have a mitogenic activity on blastema mesenchymal cells similar to that obtained with nerve extracts. The fact that two different growth factors can stimulate these cells raises the question of whether both are present in NTF and/or whether there are receptors to both EDGF I and EDGF II on mesenchymal cell membranes.

Ambystoma mexicanum↗
PubMed1986

Image analysis of blastema cell proliferation in denervated limb regenerates of the newt, Pleurodeles waltlii M.

When denervated at the medium bud stage, limb blastemas of the newt, Pleurodeles waltlii Michah, stop growing. In order to better understand the role of nerves in the cell cycle in blastemas, we studied the distribution of mesenchymal cells in the G0-1, G1, S, G2 and M phases 48 and 96 h after denervation. The cell-cycle phases were determined by examining Feulgen-stained nuclei using a SAMBA 200 (System for Analytical Microscopy in Biological Applications) cell image processor. The cell nuclei were automatically analyzed by calculating 18 parameters related to the densitometry and texture of chromatin, and the shape of each nucleus. Cell-cycle phases were classified according to the unsupervised recognition method using a SAMBA 200 system as proposed by Moustafa and Brugal for cell-kinetics analysis. The classification obtained was tested against the results of stepwise linear discriminant analysis performed according to the method of Giroud. Our results show that, in blastemas 96 h after denervation, the percentage of cells in the S, G2, and M phases decreases significantly, while the percentage of G1 and G0-1 cells increases (+ 51% for G1 cells; + 30% for G0-1 cells). Thus, it appears that denervation of medium-bud-stage limb blastemas promotes the lengthening of G1 and premature exiting of cells from the cycle into the G0-1 phase. These results show that nerves (i.e., neurotrophic factor) regulate cell kinetics during newt limb regeneration by maintaining blastema mesenchymal cells in the cell-cycle.

Animals↗
PubMed1986

[In vitro development of blastema cells in axolotl limb regeneration: effect of insulin and nerve extracts on cellular proliferation].

For the purpose of investigating the nature of the nervous factor which controls cell proliferation in limb blastema of Newts, we have cultured primary mesenchymous cells from limb blastemas of Axolotl. The cultures were carried out in Petri dishes (Primaria, Falcon) with a basal medium with contained diluted MEM supplemented with hormones (insulin, somatotropin, hydrocortisone and thyroxine). In this medium, the cells disperse from the explant from the 4th day of culture and begin to divide from the 7th day; 3 weeks later the culture begins to decline. During the course of culture, beginning at the 8th day, differentiation of myotubes and chondrogenesis occur. The mitotic index, measured on the 16th day after 48 hr of colchicine treatment, is about 1.6%. Addition of foetal calf serum to the basal medium favours cell migration and survival and stimulates proliferation (mitotic: index 6%); beef embryo extract has no effect on cell migration and a small effect on proliferation (mitotic index: 2.3%). Addition to the basal medium of insulin or nerve extracts (brain and spinal cord of adult newts, brain of 12 days chick embryos) 6 days before we measure the mitotic index stimulates proliferation in proportion to the dose, up to 6 times the mitotic index in basal medium. These results are discussed with respect to the problem of cell proliferation control during limb regeneration.

Ambystoma↗
PubMed1985

Control of the blastemal cell cycle by the peripheral nervous system during newt limb regeneration; continuous labeling analysis.

Forty-eight and 96 hr 3H-thymidine continuous labeling was analyzed on denervated mid-bud limb blastemas of Pleurodeles waltlii M. In innervated blastemas, 92 to 95% of mesenchymal cells are cycling; denervation provokes an early exiting from the cycle in G0-1(+ 15% of non-cycling cells for a 6-day denervation, + 20% for an 8 day denervation) and an elongation of the G1 phase. For epidermis only 25% (48 hr labeling) to 53% (96 hr labeling) of cells are cycling in innervated blastemas; denervation strongly decreases this percentage (+ 40% of non-cycling cells for a 6-day denervation, + 60% for an 8-day denervation). As for mesenchyme, denervation also lengthens the G1 phase of epidermal cells. So our results contradict the conclusion of other authors claiming a G2 blockage. They account for the fall in proliferation indices and the arrest of regeneration after denervation. Finally, they show that the cell cycle of regeneration cells is controlled by the neurotrophic factor.

Animals↗
PubMed1979

[Localization of the haemopoietic tissue of polychaete annelids. I. Site of haemoglobin (erythrocruorin) synthesis (author's transl)].

An iron rich tissue with an important pseudo-peroxidase activity and which specifically incorporates 55Fe and 3H delta aminolevulinic acid is localized around some vessels of the investigated Annelids : parapodial vessels of Nephthys, chloragogen coeca of Arenicola. This tissue which can be considered as haemopoietic has been studied at the EM level : it is characterized by numerous dense inclusions with pseudo-peroxidase activity and well developed granular endoplasmic reticulum and Golgi.

Animals↗
PubMed1979

[Localization of the haemopoietic tissue of polychaete annelids. II. Site of chlorocruorin synthesis (author's transl)].

The perivasal tissue of some blood vessels (antero-lateral vessels of Pomatoceros triqueter, ventral and lateral vessels of Sabella pavonina) shows a remarkable quantity of iron and pseudo-peroxidase activity. At the EM level, this tissue is characterized by numerous dense DAB positive inclusions and well developed granular endoplasmic reticulum and Golgi. Its function in chlorocruorin synthesis is discussed.

Animals↗
PubMedDate not supplied

Activities of acetylcholinesterase, choline acetyltransferase, and catecholamine production in the spinal cord of the axolotl Ambystoma mexicanum during forelimb regeneration.

Amputation of an axolotl limb causes severance of the brachial nerves, followed by their regeneration into a blastema. It is known that these nerves provide a neurotrophic factor to blastemal cells. To approach the problem of the response of spinal cord nerve centers to forelimb amputation, we have studied biosynthetic activities in the nerve centers involved in axonal injury during limb regeneration. We report that the acetylcholinesterase (AChE) activity in the spinal cord is elevated 2 days (+69%) and 7 days (+28%) after limb amputation compared with levels in unamputated control animals, but is not significantly elevated at 3 h or 15 days. The percentages of slow (3.6S and 6.0S) and fast (18S) sedimenting forms of AChE progressively decrease 2 and 7 days after amputation, while those of intermediate sedimenting forms (10.5S and 14.0S) increase. Fifteen days after amputation, lower molecular weight forms return to the control level, but the heavy molecular weight form of AChE is absent as at 7 days; consequently intermediate molecular weight forms are in a greater proportion than the other two forms. Choline acetyltransferase activity was measured only 2 days after amputation (when AChE was at its highest level). It increases by about 34% with regard to the controls. Adrenaline is higher than controls 2 days after amputation, while noradrenaline is not significantly modified. The metabolic changes observed in the spinal cord during limb regeneration probably are the result of a general reaction to the stress of amputation (transection of brachial nerves) and regeneration of nerve fibers, since similar metabolic activities were observed after a simple denervation of the two unamputated forelimbs.

Acetylcholinesterase↗