Influence of age on the plasma hormonal iodine response to thyrotropin injection in young calves]

The influence of age upon the increase in plasma hormonal iodine level following an intravenous injection of bovine TSH (0.2 USP units/kg) was studied in young jersey calves. The response to TSH increased between birth and the 7th day, then decreased regularly until the end of the third month. Reasons for these variations are discussed according to some results obtained following TSH injections.     

Immunity to coccidiosis: Gut permeability changes in response to sporozoite invasion

Zusammenfassung Mit einer neuen Methode wird gezeigt, dass die Invasion des Darmepithels von immunen Hühnern durch Sporozoiten verschiedenerEimeria-Arten zu einer vermehrten Durchlässigkeit der Gefässe führt.     

Fluorescence response of acridine orange to changes in pH gradients across liposome membranes

Summary The influence that changes in proton distribution have on the fluorescence of acridine orange was examined using negatively charged liposomes. Our results indicate that at least two mechanisms are involved: distribution of the probe between the internal aqueous phase of the liposomes and the outside medium, and binding of the probe to the liposome membranes.     

Fluorescence response of acridine orange to changes in pH gradients across liposome membranes

The influence that changes in proton distribution have on the fluorescence of acridine orange was examined using negatively charged liposomes. Our results indicate that at least two mechanisms are involved: distribution of the probe between the internal aqueous phase of the liposomes and the outside medium, and binding of the probe to the liposome membranes.     

Changes in water permeability of an insect egg in response to level of water in the environment

Summary The water permeability of eggs of the southern corn rootworm, Diabrotica undecimpunctata howardi Barber, varied depending on the previous experience of the eggs. Eggs acclimated in a water vapor system were seen to be less permeable than eggs acclimated in contact with moist paper, as measured by the rate of loss of water from the eggs and the susceptibility of the eggs to death from desiccation. This is the first known report of the ability of an insect egg to adapt to the level of water available in the environment.     

The response of plants to acid soils

Summary Interactive effects between acid deposition and the rest of the environment are the key to further understanding. Although this article deals only with plant growth in relation to the chemical state of the soil and not with aerial effects, it is still possible to illustrate a number of interactions and patterns of response among both vascular and non-vascular components of vegetation. Evidence is examined with regard to plant age, pre-treatment and the nature of nutrient supply. It includes consideration of both effects of soil on plants and of plants on soil, notes both antagonisms and symbioses, and draws attention to inducible defence systems.     

The effects of acetylation on the binding region of cartilage proteoglycans to hyaluronic acid

Summary Proteoglycans in cartilage are found as aggregates and as monomers. Evidence has been obtained indicating that hyaluronic acid, normally present in this tissue, binds together monomers into large molecular weight aggregates. In this investigation, the interacting region of the protein backbone has been studied. The results unequivocally demonstrated that the epsilon amino groups of lysine are involved in hyaluronic acid binding to proteoglycans and that their blocking by acetylation either prevents reaggregation or disaggregates the high mol. w aggregates.Supported by a grant from the Consiglio Nazionale delle Ricerche, Rome, Italy, and U. S. P. H. S., grants DE-02670 and HL 11310.     

The environment in which lymphocytes differentiate influences their ability to cooperate in vivo

Summary Whether or not parental B lymphocytes cooperate with F1 T lymphocytes depends upon the environment in which parental bone marrow cells differentiate. Only those parental B lymphocytes that have differentiated in the F1 environment are able to cooperate with F1 T lymphocytes.Postdoctoral Investigator supported by Subcontract No. 3322 from the Biology Division of Oak Ridge National Laboratory to the University of Tennessee and by the Fulbright-Hays Program.Operated by the Union Carbide Corporation for the Department of Energy.     

The mechanical response of isolated arteries to potassium

Zusammenfassung Die vasodilatatorische Wirkung der K⁺-Ionen wird bei Applikation von aussen auf Segmente der Art. facialis des Rindes, die in einer feuchten Kammer unter Druck gesetzt wurden, nachgewiesen. Die Befunde werden im Hinblick auf die Bedeutung des Kaliums für die Durchblutungsregulation im Muskel diskutiert.     

The environment in which lymphocytes differentiate influences their ability to cooperate in vivo.

Whether or not parental B lymphocytes cooperate with F1 T lymphocytes depends upon the environment in which parental bone marrow cells differentiate. Only those parental B lymphocytes that have differentiated in the F1 environment are able to cooperate with F1 T lymphocytes.     

The response of human skeletal muscle tissue to hypoxia

Hypoxia refers to environmental or clinical settings that potentially threaten tissue oxygen homeostasis. One unique aspect of skeletal muscle is that, in addition to hypoxia, oxygen balance in this tissue may be further compromised when exercise is superimposed on hypoxia. This review focuses on the cellular and molecular responses of human skeletal muscle to acute and chronic hypoxia, with emphasis on physical exercise and training. Based on published work, it is suggested that hypoxia does not appear to promote angiogenesis or to greatly alter oxidative enzymes in skeletal muscle at rest. Although the HIF-1 pathway in skeletal muscle is still poorly documented, emerging evidence suggests that muscle HIF-1 signaling is only activated to a minor degree by hypoxia. On the other hand, combining hypoxia with exercise appears to improve some aspects of muscle O₂ transport and/or metabolism.     

The humoral immune response to heat shock proteins

Humoral immune reactions to heat shock proteins (hsp) from microorganisms are one aspect of microbial infections in humans. The production of antibodies which are specific to epitopes present on procaryotic hsp leads also to the appearance of cross-reactive serum antibodies in the host organism that react with human hsp. This article discusses the consequences of such autoreactive antibodies for the host in context with the development of immune tolerance and autoimmune diseases, especially rheumatoid arthritis (RA), and in experimental animal models for arthritis such as adjuvant arthritis in rats. On the basis of epitope cross-reactivity between hsp and other host proteins, a hypothesis is presented for the development of autoimmune disease following the production of hsp-specific antibodies.     

The cellular immune response to heat shock proteins

T lymphocytes, which are central to almost every immune response, frequently recognize microbial hsp60. Such cells could provide an early defense mechanism against pathogenic microbes. However, T cells also recognize epitopes of hsp60 shared by microbe and host. Not only conventional / T cells respond to hsp60; / T cells do so, as well. In fact, certain / T cells seem to have a particular preference for this molecule. Recognition of stressed host cells expressing hsp60 could facilitate the scavenger function of the T cell system. On the other hand, such recognition could be involved in autoimmune disease.     

The restoration of the glycaemic response to adrenaline in the bursectomized fowl

Résumé Des poussins boursectomisés traités avec du plasma de poussins intacts ne subissent pas de perte de réponse glycémique à l'insuline, mesurée d'après les changements de niveaux du glucose dans le plasma sanguin. Il est suggéré que les résultats sont compatibles avec l'hypothèse selon laquelle la bourse de Fabricius est une glande endocrine.