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Biomedical subjects

M Perez

Publications and source records attributed to M Perez.

At least 199 records · Page 11Linked to original sources
PubMed1980

Expression of foreign H-2-like antigens by a chemically-induced murine tumour (MCG4).

Alien H-2k-like antigens were found to be expressed by a methylcholanthrene induced tumour of BALB/c (H-2d) origin. H-2 specificities of the k haplotype were detected on this tumour by a variety of serological techniques, including 51Cr-release cytotoxicity, microradioassay and absorption. The antisera employed were conventional polyspecific alloantisera, typing sera with restricted specificty and monoclonal hybridoma-derived anti-H-2k antibodies. The tumour has a low expression of the private specificty 31, which characterizes Kd molecules, and does not seem to express the private specificities of Dd, Kk and Dk molecules. It appears to express predominantly alien H-2-like antigens which are very similar to but not identical with normal H-2k molecules.

Animals↗
PubMed1979

Absence of four H-2d antigenic specificites in an H-2d sarcoma.

MCG4 is a BALB/c sarcoma induced as a solid tumour with 0.2 mgs of methylcholantrene. The primary tumour was serially transplanted subcutaneously in syngeneic mice. The ascites form obtained was sued to study the expression of H-2 antigeneic specificities in a postlabelling radioassay. MCG4 did not express H-2D.4 (private specificity of H-2d haplotypes) as well as H-2.3, H-2.8 and H-2.13 (public specificities). In addition it expressed H-2.5 (a public specificity not present in H-2d cells). These results were confirmed by quantitative absorption analysis using MCG4 and positive-negative normal lymphoid cells for a particular specificity. Results are discussed with regard to the control of expression of H-2 antigens by regulatory genes.

Animals↗
PubMed1979

A syngeneic anti tumor serum recognizing a complex H-2 alloantigen.

A methylcholanthrene induced tumor of BALBc (H-2d) origin had a high rate of spontaneous regression when transplanted into syngeneic animals. The tumor induced in BALB/c mice iso-antibodies with high anti-tumor cytotoxic activity. A specificity analysis of such BALB/c anti MCG4 sera revealed that the antibodies were directed against a tumor antigen which is very similar to H-2- alloantigens (e.g. H-2.5) expressed on normal cells of certain foreign mouse strains. The sera also reacted with nine out of ten B10.W congenic strains bearing H-2wi haplotypes derived from wild mice. Whether the tumor antigen is identical with foreign H-2 antigens or only cross-reactive cannot be decided at present.

Animals↗
PubMed1972

Molecular buoyancy and osmotic equilibrium.

Measurements of osmotic equilibrium of colloidal solutions, ranging from 170,000 to 20,000 in molecular weight, show that the negative buoyancy of the solute molecules is additive to the osmotic pressure. Seen together with earlier measurements of positive buoyancy of oil suspensions, these data confirm that the osmotic interaction between solute and solvent at equilibrium is purely a force-coupling at the free surface.

Journal Article↗
PubMed1971

Experiments on osmosis with magnetic fluid.

Experiments on a ferromagnetic colloidal fluid at equilibrium showed equality between magnetic and osmotic force; this result identifies solute pressure against the free surface as the cause of the negative solvent pressure. Except for water of hydration, there is no other osmotic interaction between solute and solvent.

Journal Article↗
PubMed1971

Effect of gravity on osmotic equilibria.

Experiments with colloidal suspensions of oil and iron oxide at equilibrium show that the buoyancy of the suspended particles is additive to the osmotic pressure and that the relation remains with the free surface and not with the membrane. The experiments contribute to the general concept that osmotic pressure is caused by the dispersal pressure of solute molecules and that the osmotic interaction with the water at equilibrium is due solely to a coupling at the free surface.

Journal Article↗