Survival of tumor fragments as a function of temperature: correlation with electric impedance]

The ability of small pieces of Rat Walker's tumour carcinome 256 to develop a subcutaneous tumour on another Rat is dependent on the value and the duration of heat treatment.     

Montane and piedmont chorus frogs (Pseudacris triseriata): Metabolic rate as a function of temperature

Zusammenfassung Die Stoffwechselraten von Fröschen (Pseudacris triseriata) aus Tiefland- und Bergpopulationen wurden bei 10 C und 20 C bestimmt. Die beiden Populationen unterschieden sich nicht signifikant in der Stoffwechselrate bei den 2 Testtemperaturen.     

Oxygen consumption of hibernating worker ants Dolichoderus quadripunctatus as a function of temperature and level of population]

The oxygen consumption of "hibernating" ants shows a grouping effect translated by a significant decrease in the level of oxygen consumption as a function of grouping effect. The general relation between oxygen consumption and the living body mass is the same, if the living material belongs to a single animal, or a social community of ants.     

Visual stimulus localization as a function of brightness

Résumé Dans une tâche consistant à localiser un point sur une barre horizontale ou verticale, on mesure l'information transmise en fonction de l'éclairement et de l'information du stimulus. On trouve une relation linéaire directe entre l'information transmise et le logarithme de l'éclairement. Cette relation reste valable pour diverses quantités d'information émise.

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Partly supported by the Fonds National belge de la Recherche Scientifique.     

Method for the quantitative evaluation of platelet function in blood coagulation

Zusammenfassung Eine Methode zur Auswertung der funktionellen Plättchenaktivität wird beschrieben. Isolierte Plättchen in konstanter Zahl (300000/cu.mm) werden einem alle übrigen Gerinnungsfaktoren in konstanter Menge enthaltenden Substrat zugesetzt. Prozente können von den Gerinnungszeiten durch eine Eichkurve ermittelt werden.     

Cell fusion as a mechanism for the origin of polyploid cells in vitro

Zusammenfassung In Kulturen vonPeromyscus maniculatus und inMuntiacus muntjak wurden Tetraploidzellen gefunden, die als Produkte von Zellfusionen aufgefasst werden. Es wird angenommen, dass die ursprünglichen diploiden Elemente sich im Zeitpunkt der Fusion in verschiedenen Phasen des Zellzyklus befunden haben.

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Supported in part by NIH fellowship No. 1-F02-CA-42, 531-02 from the National Cancer Institute, USPHS grant No. GM-15361, and Grant No. E 286 from the American Cancer Society.     

Ethanol ingestive behavior as a function of central neurotransmission

Summary Uncontrollable alcohol ingestive behavior has been linked to deficits of central neurotransmission. The pineal gland plays an important role in modulating ethanol intake in numerous animal species. The opioidergic (i.e. -endorphin, enkephalin, and dynorphin) system is involved in both the actions of alcohol and opiates, as well as craving and/or genetic predisposition towards abuse of these two agents. Furthermore, there is significant evidence to link ingestive behaviors with the ventral tegmental accumbens-hypothalamic axis, whereby the biogenic amines dopamine and serotonin are reciprocally involved. Evidence is presented which implicates the striatum and the hypothalamus as possible specific loci for regional differences between alcohol-preferring and alcohol-nonpreferring mice. We believe that photoperiod-induced alcohol ingestive behavior may involve alterations in both pineal and hypothalamic opioid peptides.     

Ethanol ingestive behavior as a function of central neurotransmission

Uncontrollable alcohol ingestive behavior has been linked to deficits of central neurotransmission. The pineal gland plays an important role in modulating ethanol intake in numerous animal species. The opioidergic (i.e. beta-endorphin, enkephalin, and dynorphin) system is involved in both the actions of alcohol and opiates, as well as craving and/or genetic predisposition towards abuse of these two agents. Furthermore, there is significant evidence to link ingestive behaviors with the ventral tegmental accumbens-hypothalamic axis, whereby the biogenic amines dopamine and serotonin are reciprocally involved. Evidence is presented which implicates the striatum and the hypothalamus as possible specific loci for regional differences between alcohol-preferring and alcohol-nonpreferring mice. We believe that photoperiod-induced alcohol ingestive behavior may involve alterations in both pineal and hypothalamic opioid peptides.     

Possible involvement of the phloem sealing system in the acceptance of a plant as host by an aphid

Possible reasons for the rejection of some lines ofTriticum monococcum (Tm44 and Tm46) by the aphidSitobion avenae were explored. In allT. monococcum lines studied, whether unfavourable (non-host/resistant plant) or favourable (host/susceptible plant), the concentrations of hydroxamic acids, a family of aphid-resistance factors in cereals, were significantly lower than the levels in the favourable host-plantTriticum aestivum cv. Therefore, hydroxamic acids did not account for the host/non-host patterns observed. Phloem sap was collected by stylectomy from young seedlings of favourable and unfavourable plants. In non-aphid-resistant genotypes, the success in stylectomy, the proportion of amputated stylets resulting in long (>1 min) exudations, the average duration of exudation, and the final volume of sap exuded, were higher than in the aphid-resistant genotypes. It is concluded that aphid interference with the phloem sealing system of the plant is a likely mechanism of rejection ofT. monococcum lines Tm44 and Tm46 as hosts byS. avenae.     

Hepatopancreatic amylase activity as a function of warm-adaptation in a fresh-water field crab

Zusammenfassung Im Hepatopankreas der Krabben sind Fermentsysteme, die eine Wärmeadaptation besitzen. Diese lässt sich mit ähnlichen physiologischen Erscheinungen bei kaltblütigen Vertebraten vergleichen.     

Adiponectin as a tissue regenerating hormone: more than a metabolic function

The great interest that scientists have for adiponectin is primarily due to its central metabolic role. Indeed, the major function of this adipokine is the control of glucose homeostasis that it exerts regulating liver and muscle metabolism. Adiponectin has insulin-sensitizing action and leads to down-regulation of hepatic gluconeogenesis and an increase of fatty acid oxidation. In addition, adiponectin is reported to play an important role in the inhibition of inflammation. The hormone is secreted in full-length form, which can either assemble into complexes or be converted into globular form by proteolytic cleavage. Over the past few years, emerging publications reveal a more varied and pleiotropic action of this hormone. Many studies emphasize a key role of adiponectin during tissue regeneration and show that adiponectin deficiency greatly inhibits the mechanisms underlying tissue renewal. This review deals with the role of adiponectin in tissue regeneration, mainly referring to skeletal muscle regeneration, a process in which adiponectin is deeply involved. In this tissue, globular adiponectin increases proliferation, migration and myogenic properties of both resident stem cells (namely satellite cells) and non-resident muscle precursors (namely mesoangioblasts). Furthermore, skeletal muscle could be a site for the local production of the globular form that occurs in an inflamed environment. Overall, these recent findings contribute to highlight an intriguing function of adiponectin in addition to its well-recognized metabolic action.     

Intra-vascular glucocorticoid metabolism as a modulator of vascular structure and function

The ability of glucocorticoids to directly alter arterial function, structure and the inflammatory response to vascular injury may contribute to their well-established link with the development of cardiovascular disease. Recent studies have emphasised the importance of tissue-specific regulation of glucocorticoid availability by the 11 β-hydroxysteroid dehydrogenase (11HSD) isozymes, which inter-convert active glucocorticoids and their inactive metabolites. The expression of both type 1 and type 2 11HSDs in the arterial wall suggests that prereceptor metabolism of glucocorticoids may have a direct impact on vascular physiology. Indeed there is evidence that 11HSDs influence glucocorticoid-mediated changes in vascular contractility, vascular structure, the inflammatory response to injury and the growth of new blood vessels. Hence, inhibition of 11HSD isozymes may provide a novel therapeutic target in vascular disease. Received 19 September 2005; received after revision 1 November 2005; accepted 25 November 2005