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Biomedical subjects

B Coulomb

Publications and source records attributed to B Coulomb.

43 records · Page 3Linked to original sources
PubMed1983

Endogenous peroxidases in normal human dermis: a marker of fibroblast differentiation.

Incubation of unfixed and unfrozen slices of normal human skin allows visualization of a peroxidase activity associated with the perinuclear envelope and with the endoplasmic reticulum of resident dermal macrophages, dermal mastocytes, and also of some dermal fibroblasts. No peroxidase activity can be detected in fibroblasts cultivated in monolayer, while 80% of fibroblasts in an "in vitro" collagen lattice, called a dermal equivalent, express a peroxidase activity in the perinuclear envelope and the endoplasmic reticulum. Hence expression of this peroxidase activity in normal human skin fibroblasts serves as a marker of fibroblast differentiation and seems to depend on an interaction to fibroblast with the elements of a three-dimensional matrix.

Adult↗
PubMed1983

The reconstitution of living skin.

A living-skin equivalent useful as a skin replacement and as a model system for basic studies has been fabricated and tested extensively. It consists of two components: (1) a dermal equivalent made up of fibroblasts in a collagen matrix that is contracted and modified by the resident cells, and (2) an epidermis that develops from keratinocytes "plated" on the dermal equivalent. A multilayered keratinizing epidermis with desmosomes, tonofilaments, and hemidesmosomes forms. Basement lamella formation occurs within 2 weeks in vitro when rat cells are used. With human cells, crypt or pseudofollicular morphogenesis is observed in vitro within 3 weeks after plating cells on the dermal equivalent. Autografts and isografts of rat-skin equivalents made with cultured cells from biopsies are rapidly vascularized, block wound contraction, and persist essentially for the lifespan of the host. Seven to 9 days after grafting, donor cells become activated biosynthetically and mitotically. By 1 year, the dermal population decreases to a normal level and the matrix has been extensively remodeled. The grafts remain free of hair and sebaceous glands. Grafts to rats have been in place for over 2 years. Now, allografts of dermal equivalents have been made across a major histocompatibility barrier and are not rejected. The persistence of cellular elements of the grafts is monitored by use of a genetic marker. Challenge of the allograft with a second skin-equivalent graft after 1 month does not result in rejection of the original graft or of the second skin-equivalent graft. We propose that allografts of tissue equivalents are tolerated because cells with class II antigens are selected against during in vitro cultivation and are excluded from the graft. Thus the fabrication of skin-equivalent tissues or of other equivalent tissues with parenchymal cells that do not bear class II antigens may render transplants of such tissues immunologically acceptable despite the presence of allogeneic cells. The capacity to graft across major histocompatibility barriers using living tissue equivalents may have important clinical significance.

Animals↗
PubMed1983

[In vitro metabolism of 4-benzylisoquinolines, analogs of papaverine].

A comparative study was made on sliced Rat liver of the in vitro disappearance of papaverine, PV 2 6,7-dimethoxy-4-(parachlorobenzyl)isoquinoline and its mono and di isopropoxy derivatives. Data show that papaverine and PV 2 are equally sensitive to oxygenases, although 7 mono and 6,7 di-isopropoxy derivatives are much less so, being more bulky and undergo in enzymic O-dealkylation less easily. The data also show that PV 2 and 6-isopropoxy desmethoxy PV 2 disappear at the same rate, more readily than the 7 isopropoxy isomer. This confirms the in vivo results previously reported. The antispasmodic in vitro activity of these compounds is reported.

Animals↗
PubMed1979

Normal and benzo(a)pyrene-transformed fetal mouse brain cell. I. Tumorigenicity and immunochemical detection of glial fibrillary acidic protein.

Primary cultures of whole brain and cortex cells origination from 14-day-old A/Jax or C3H mouse fetuses were treated with benzo(a)pyrene (B(a)P) for 24 h. After 7 to 8 passages a malignant transformation was observed in the chemically treated whole brain and cortex cultures. Control cultures of cortex remained non-transplantable during the whole experiment (up to 14 passages) whereas in the control cultures originating from whole brain a spontaneous transformation appeared after 11 passages. With horseradish peroxidase-labelled antibody, the specific glial fibrillary acidic protein (GFAP) was detected in both control and transformed total brain and cortex cultures, and in the tumors initiated by the in vitro transformed cells. This finding shows that glialike cells persisted after a long in vitro maintanance and transformation.

Animals↗
PubMed1979

[Spontaneous transformation and long term culture of foetal mouse glial cells (author's transl)].

Six cell lines originated from foetal mouse brain were maintained in vitro for more than two years. The morphology of most of these cultures suggests their glial character. This is corroborated, for some lines, by the presence of specific glial protein (Glial fibrillary acidic protein, or GFAP). Five out of these lines remained not transplantable in animals during all the experiments. However one of them went through a spontaneous transformation at the eleventh population doubling. This culture, after transformation remained glial and when injected in animals, induced GFAP containing tumors.

Animals↗