Villus growth and cell replacement in the small intestine of the neonatal pig

Summary Cells produced in the crypts of newborn pig ileum migrate onto villi during development. There is little or no corresponding loss of cells from villus tips during the first week of postnatal life. Villus growth during this period is largely responsible for the slow rate of cellular renewal seen to take place.     

Differentiation antigens in keratinocytes]

By means of indirect immunofluorescence with human sera it has been demonstrated that cytoplasmic components of the basal cell layer showed antigenic differences as compared to the upper cell layers. Moreover there were differences whether the cells were involved in a mucous, a parakeratinized or an orthokeratinized differentiation.     

HLA-restricted T-cell recognition of Epstein-Barr virus-infected B cells

In mice the cytotoxic T-cell response to several types of virus is influenced by genes within the major histocompatibility complex; in particular, genetic control is exercised at the effector cell level through a requirement that virus-specific cytotoxic T cells recognise viral antigens in association with H-2K and H=2D region gene products on the surface of infected cells. In man the restriction which the analogous HLA-A, -B and -C-region gene products might place on virus-specific T-cell function is still in dispute. The earliest and most controversial evidence concerns the Epstein-Barr virus (EBV), a B lymphotropic agent which causes infectious mononucleosis (IM) and which induces an unusually vigorous T-cell response; cytotoxic T cells from IM patients' blood were shown to be EBV-specific yet, in contrast to mouse systems, apparently free of any obvious HLA restriction. Since then T-cell recognition of EBV-infected B cells has assumed particular significance as a model system for the study of cytotoxic T-cell function in man. This report describes the results of a new approach clearly indicating that HLA-A and -B region products do indeed have a role in this system.     

Interferon-dependent induction of mRNA activity for (2'-5')oligo-isoadenylate synthetase

At least three different enzymes involved in the regulation of protein synthesis are induced in a variety of cells by interferon (IFN). Sensitive assays for these enzymes have been developed and used to establish the specificity, dose dependence and time course of their induction by IFN. One of these enzymes, the oligo-isoadenylate synthetase E, whose product (2'-5')pppApApA activates the latent ribonuclease F, is increased over 50-fold after IFN treatment. We describe here the assay for an mRNA from IFN-treated mouse L cells, that produces oligo-isoadenylate synthetase activity when injected into Xenopus oocytes. This mRNA is found in the cells only after exposure to IFN. The mRNA increases in mouse L cells with the same time course as the enzyme activity itself. In particular, there is a 3-h lag period between IFN addition and the onset of enzyme and mRNA accumulation. Using anti-IFN antibodies, we show that during this lag period the continued interaction of IFN with the cells is necessary for the full induction of the oligo-isoadenylate synthetase.     

125I-Insulin is preferentially internalized in regions of the hepatocytes rich in lysosomal and Golgi structures

Summary ¹²⁵I-Insulin initially localizes to the plasma membrane of isolated rat hepatocytes but is subsequently internalized and preferentially associates with lysosomal structures. In the present study, we show that this preferential association to lysosomes occurs in regions of the cell rich in lysosomal and Golgi structures.This work was performed while Dr Gorden was visiting professor of the Institute of Histology and Embryology, University of Geneva, Geneva, Switzerland.This work was supported by grant No. 3.120.77 from Swiss National Science Foundation. We thank M.M. Sidler-Ansermet, O. Jerotic and N. Maalaoui for their valuable help.     

The effects of oxamate on the contractility of isolated rat atria

Zusammenfassung Oxamat, das die Lactat-Dehydrogenase hemmt, erniedrigt die Kontraktionsfähigkeit des Vorhofs mit und ohne Anwesenheit von Glucose im Medium und bei Hinzufügung von 2-DG oder Atropin. Hohe Konzentration von Pyruvat erhöht die Depression von Oxamat auf den Vorhof im Glucose-Milieu. Oxamat sensibilisiert das Gewebe für funktionellen Abbau durch Glycolyse.

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This research was supported by grants No. 1441 and No. HE-994801 from Consejo Nacional de Investigaciones de la República Argentina, and from the National Institute of Health, respectively.

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Research Fellow from the Consejo Nacional de Investigaciones de la República Argentina.

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Established Investigator from the Consejo Nacional de Investigaciones de la República Argentina.