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Biomedical subjects

M Prunieras

Publications and source records attributed to M Prunieras.

At least 55 records · Page 3Linked to original sources
PubMed1978

A syndrome associating partial albinism and immunodeficiency.

Two unrelated patients with partial albinism, frequent pyogenic infections and acute episodes of fever, neutropenia and thrombocytopenia are described. Their pigmentary dilution was characterized by large clumps of pigments in the hair shafts and an accumulation of melanosomes in melanocytes. Melanocytes had few short dendritic expansions, and keratinocytes were hypopigmented. No or few Langerhans' cells were detected in skin by electron microscopy and ATP-ase reactions. This pigmentary dilution, different from all other human albinisms, resembles the unique defect of the mutant dilute (d-d) mouse. Despite the presence of an adequate number of T and B lymphocytes, the patients were hypogammaglobulinemic, deficient in antibody production and incapable of manifesting delayed skin hypersensitivity or of rejecting skin grafts. Their leukocytes did not stimulate normal lymphocytes and could not generate cytotoxic cells during mixed leukocyte reaction. T lymphocytes of one patient were unable to exert a helper effect on the maturation of B lymphocytes into immunoglobulin-containing cells following in vitro stimulation with pokeweed mitogen. This suggests that the humoral deficiency might be secondary to a defect of helper T lymphocytes. Granulocytes did not show any morphologic abnormality, and their bactericidal activity was only moderately reduced. An increased number of polymorphonuclear leukocytes with polar distribution of Concanavaline A (Con A) receptors (capping) was found in one patient and her parents. The family histories suggest that this syndrome is transmitted as an autosomal recessive character.

Albinism↗
PubMed1978

UV-induced unscheduled DNA synthesis in guinea pig skin melanocytes isolated in culture.

Pigmented melanocytes isolated in culture from the epidermis of guinea pig ears were used to study the unscheduled DNA synthesis (UDS) induced by ultraviolet (UV) irradiation at 254 nm. After irradiation, the cells were labeled for 6 hr with 3H-thymidine (3HTdR), fixed, dehydrated, and flat embedded in Epon. Radioautographs were made on serial 0.5-1 micrometer thick sections of the cultures in order to distinguish silver grains from pigment granules. Cells irradiated with 5, 10, or 50 joules (J) m-2 showed a 3HTdR uptake due to UDS, whereas their proliferative ability, measured by the 3HTdR uptake due to scheduled DNA synthesis, was very low. For the same UV doses, UDS was lower in melanocytes than in guinea pig fibroblasts and keratinocytes.

Animals↗
PubMed1978

Studies on guinea pig skin cell cultures. VII. Statistical analysis of growth and maturation.

Thymidine uptake; incorporation of amino acids into perchloric acid extract and HCl extract (corresponding grossly to poorly and highly organized proteins respectively); cell fraction DNA and cell fraction protein contents have all been measured daily from day 1 to day 8 in primary cultures of epidermal keratinocytes (EK) and dermal fibroblasts (DF). Correlations between these five biochemical parameters (or variables) have been sought when using the statistical method of principal component analysis. The analysis of whole data of EK and DF populations taken together revealed that DNA content is a major distinguishing factor between these two cell types. The analysis of variables of each cell type taken independently showed that DF are essentially characterizable by their tendency to synthesize both poorly and highly organized proteins, whereas EK are more prone to DNA and highly organized protein synthesis. Thus, EK and DF in culture can be readily distinguished statistically by analysing their growth and maturation characteristics. It is even likely that time study of thymidine and amino acid incorporation would suffice to characterize these two cell types in vitro.

Amino Acids↗
PubMed1977

Preferential replication of Sézary cells in the epidermis.

Skin biopsies from three patients with Sézary Syndrome have been labeled in vitro with H-3Thymidine. Labeled cells have been counted in semithin Epon embedded sections and characterized by electron microscopic autoradiography. The ratio of labeled Sézary cells to total lymphocytes was two to four times higher in the epidermis than in the dermis. It is concluded that Sézary cells replicate in the skin and that epidermal cells seem to possess new blastogenic properties in Sézary Syndrome.

Autoradiography↗
PubMed1977

Studies on guinea pig skin cell cultures. VI. Growth kinetics of epidermal keratinocytes and dermal fibroblasts.

The growth kinetics of epidermal keratinocytes (EK) and dermal fibroblasts (DF) have been determined by four different methods: incorporation of 3H-thymidine into DNA (3H-microgram DNA ratio); 3H-thymidine/14C amino acid incorporation ratio (3H:14C ratio); 3H-thymidine labelled nuclei, and colchicine-blocked metaphase counts. The growth curve of EK was no different when plotted with the 3H:14C ratio than with the 3H-microgram DNA ratio. However, this was not true for DF. The replacement of sodium bicarbonate with Hepes buffer in the culture medium did not greatly affect the shape of the EK growth curve, whereas the DF growth curve became diphasic instead of monophasic. The elimination of mature (differentiated) keratinocytes from the very onset of EK culture had a profound effect on the EK growth curve. DNA synthesis peaked at day 1 in cultures without, instead of day 9 in cultures with differentiated cells. Furthermore, mitotic activity did not show up before day 6. This suggests that (i) EK in culture are sensitive to the G1 inhibitor released by differentiated epidermal cells, and (ii) they remain in G2 for about 5 days. Thus, EK in culture seem to continue to be susceptible, as in vivo, to homeostatic regulation through the action of G1-G2 inhibitors.

Animals↗
PubMed1976

Studies on guinea pig skin cell cultures. V. Co-culture of pigmented melanocytes and albino keratinocytes, a model for the study of pigment transfer.

Mixed cultures of melanocytes (M) and keratinocytes (K) are easily obtained from pigmented guinea pig ear skin. They are suitable for the study of pigment transfer from M to K. However, quantitation is difficult because many K are already loaded with pigment prior to cultivation. A technique is presented in which pigment-producing M are co-cultured with K of albino origin. Pigmented guinea pig ear skin is split with trypsin and basal cells including M are harvested. The cell suspension is treated with sodium citrate which prevents the attachment of K (but not of M) to the culture substrate. Ninety per cent pure M cultures are obtained. Five to seven days later, another basal cell suspension is prepared, this time from albino ear skin. This second suspension is seeded on top of the pigment-forming culture of M. The number of contacts between albino K and pigment-forming M increases as a direct function of time. Contrarily, the number of K which become pigmented increases until the fifth day of co-culture and decreases thereafter.

Animals↗