Fluorescent mast cell in precancerous mouse skin

Résumé L'application d'un hydrocarbure cancérigène à la peau de la souris est suivie d'une mastocytose très nette qui évolue dans le tissu conjonctif. Après traitement au formaldéhyde d'une coupe gelée, quelques mastocytes prennent au microscope à fluorescence une couleur brun doré. Par essai direct et par chromatographie sur papier, on a constaté que la substance fluorescente est le dérivé-carboline de la 5-hydroxy-tryptamine.     

Specific inhibition of mast cell disruption in vitro

Résumé Les «mast cells» péritonéales de Rats hypersensibles à la -globuline humaine, subissent une «dégranulation» in vitro en présence de l'antigène. Cette «dégranulation» est inhibée par les antisérums spécifiques. Les sérums de Rats hypersensibles ont la propriété de sensibiliser au même antigène les «mast cells» de Rats normaux.     

Biological activity and pathological implications of misfolded proteins

The physiological metabolism of proteins guarantees that different cellular compartments contain the appropriate concentration of proteins to perform their biological functions and, after a variable period of wear and tear, mediates their natural catabolism. The equilibrium between protein synthesis and catabolism ensures an effective turnover, but hereditary or acquired abnormalities of protein structure can provoke a premature loss of biological function, an accelerated catabolism and diseases caused by the loss of an irreplaceable function. In certain proteins, abnormal structure and metabolism are associated with a strong tendency to self-aggregation into a polymeric fibrillar structure, and in these cases the disease is not principally caused by the loss of an irreplaceable function but by the action of this new biological entity. Amyloid fibrils are an apparently inert, insoluble, mainly extracellular protein polymer that kills the cell without tissue necrosis but by activation of the apoptotic mechanism. We analyzed the data reported so far on the structural and functional properties of four prototypic proteins with well-known biological functions (lysozyme, transthyretin, β2-microglobulin and apolipoprotein AI) that are able to create amyloid fibrils under certain conditions, with the perspective of evaluating whether the achievement of biological function favors or inhibits the process of fibril formation. Furthermore, studying the biological functions carried out by amyloid fibrils reveals new types of protein-protein interactions in the transmission of messages to cells and may provide new ideas for effective therapeutic strategies. Received 9 November 1998; received after revision 15 January 1999; accepted 15 January 1999     

Chromatography of mast cell sensitizing antibodies in guinea-pigs

Résumé L'inoculation intraveineuse d'albumine humaine (HA), provoque chez le cobaye l'apparition d'un anticorps (-1) sensibilisant les cellules mast (CM) homologues. L'inoculation dans le coussinet plantaire (HA et adjuvant de Freund complet) fait apparaître deux anticorps: l'un (-2) sensibilisant les CM hétérologues, l'autre (dans le-1 ainsi que dans le-2) sensibilisant les CM homologues.

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We thank Mrs.Nava Raz, Mrs.Tamar Minai and Mr.I. Ofek for technical assistance.     

Influence of hormones and X-Rays upon the tissue mast cell

Résumé Diverses hormones sexuelles et pituitaires étaient sans effet sur les labrocytes du mésentère et de la peau du rat. L'irradiation partielle du rat et du hamster provoquait des altérations signifiques dans les tissus irradiés mais était sans effet dans les tissus non irradiés.

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This work was performed under auspices of U.S. Atomic Energy Commission.     

The effect of pH on mast cell damage by antihistamines

Resumen Se demuestra que la acción de antihistamínicos sobre los mastocitos de la rata y del cobayo depende del pH. Los antihistamínicos estudiados fueron activos en pH 8.4, pero fueron totalmente inhibidos cuando se disminuyó el pH. También se verificó que la histamina no antagoniza la acción de los antihistamínicos sobre los mastocitos cuando el pH fue mantenido en 8.4.     

Isotopic composition of cattle pancreatic stones: Biological and geochemical implications

Summary Latitudinal variations of the O¹⁸/O¹⁶-ratios of carbonate and phosphate of cattle pancreatic stones parallel a similar pattern of oxygen isotope values in rain water. C¹³/C¹²-ratios were virtually identical for the 7 cases studied. Isotopic measurements of mammalian hard tissues may be used for studying short-term climatic variations through Quaternary.This research was supported by CNR-University of Pisa, contracts No. 74.723 and No. 75.0102.     

Studies on the role of the mast cell in local calcergy

Summary The treatment of animals with disodium chromoglycate and/or cytochalasins which inhibit mast cell degranulation has no influence on the development of local calcergy induced in the mouse by the s.c. injection of lead acetate.     

High fat diet and mast cell count in rat mesenterium

Zusammenfassung 57 Ratten mit isokalorischer Diät und verschiedenem Fettgehalt wurden auf 3 Gruppen verteilt. Die Ratten der Gruppe mit Diät von hohem Fett- und Cholesterolgehalt zeigten eine statistisch signifikante Verminderung der Heparinocytenzahl in den Mesenterien.     

The inhibitory effect of histamine on mast cell damage induced by antihistamines

Resumen Se demonstra la capacidad de la histamina para inhibir las alteraciones de los mastocitos de la rata y cobayo producidas por diversos antihistamínicos (difenhidramina, prometazina, clorciclizina, clorpromazina). Diferentes concentraciones de histamina fueron necesarias para antagonizar los distintos antihistamínicos. Se sugiere la existencia de un antagonismo antihistamínico — histamina a nivel mastocitario.     

Histochemical comparison of mast cell and globule leucocyte granules in the rat

Zusammenfassung Es werden die Granulationen von Leukozyten, welche im Dünndarm der Ratte infolge einer Helmintiasis auftraten, mit den Granulationen der Mastzellen im s.c. Gewebe verglichen. Die Granulationen in den Mastzellen verhalten sich gegenüber Heparin und Histamin positiv, während die Leukozyten eine negative Reaktion ergeben. Dies weist darauf hin, dass die beiden Zellen nicht identisch sind und wohl aus verschiedener Matrix stammen.     

A calcifying topical reaction to mast cell depletors in the rat

Résumé Une réaction de calcification est décrite chez le Rat albinos à l'endroit sous-cutané d'injection de certains dégranulateurs de mastocytes (ex: 48/80). La calcification intéresse surtout le muscle peaucier et les nerfs sous-cutanés. L'accent est porté sur le neurotropisme de ces substances et sur la simplicité de la réaction permettant une étude aisée des relations entre mastocytes et calcification dite dystrophique.

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This work was supported by the Medical Research Council (Canada) and the National Institute of Neurological Diseases and Blindness, U.S.P.H.S.     

The localization of3H-corticosterone in mast cell granules by electron microscopic autoradiography

Zusammenfassung Der Einbau von 1,2-³H-Corticosteron in die Mastzellen der lymphatischen Organe wurde bei Mäusen untersucht. Bei gleichzeitiger Anwendung von Autoradiographie und Elektronenmikroskopie konnte das Corticosteron in den Mastzellen nachgewiesen werden.     

CADM1 isoforms differentially regulate human mast cell survival and homotypic adhesion

Cell adhesion molecule 1 (CADM1), expressed by human lung mast cells (HLMCs), mediates their adhesion to airway smooth muscle (ASM), and contributes to ASM-dependent HLMC proliferation and survival. CADM1 is expressed in alternatively spliced isoforms, but those present in HLMCs and their function are not known. We cloned three functional and one cryptic non-functional isoform with alternative splicing between exons 7/11 and 1/2, respectively, from HLMCs and human MC lines (HMC-1 and LAD2). Differentiated HLMCs and LAD2 cells expressed the functional isoform SP4 containing exons 7/8/11 (~80% of clones), as well as SP1 (exons 7/8/9/11) and a novel SP6 (exons 7/8/9/10/11). In contrast, immature HMC-1 cells expressed only functional SP4. SP4 overexpression in HMC-1 cells and HLMCs augmented homotypic adhesion to a greater extent than SP1 in various conditions. In contrast, CADM1 downregulation abolished homotypic adhesion, indicating that CADM1 is the sole receptor mediating mast cell aggregation. CADM1-mediated adhesion was enhanced by the presence of cell survival factors. SP1 overexpression in HMC-1 cells compromised survival compared to SP4 overexpression or control. CADM1 downregulation resulted in reduced viability and decreased expression of the pro-survival protein Mcl-1(L), but not Blc-2 or Bcl-X(L), and increased caspase-3/7 activity in both HMC-1 cells and HLMCs. This coincided with decreased basal Kit levels in HLMCs. In summary, human MCs express multiple CADM1 isoforms which exhibit differential regulation of survival and homotypic adhesion. The most highly expressed SP4 isoform is likely to contribute to MC aggregation and longevity in mastocytosis, and augment the pathophysiology of allergic diseases.