Lack of concordance in the effect of large doses of phenformin on insulin secretion and glycemia. Tentative analysis]

In the anesthetized dog normal or pretreated with phenformin (20 mg/kg per os) for 7 days, a subcutaneous injection of this biguanide (20 mg/kg) triggers a considerable hyperinsulinemia without concomitant hypoglycemia. The insulin secreted by these animals is biologically active on rat epididymal fat pads. On the other hand, epididymal fat pads of rats pretreated with phenformin display a lower response to insulin than that of non treated rats. The hypoglycemic effect of the same dose of insulin is less important in the normal dog after chronic pretreatment with phenformin.     

Deriving artificial models of visitors from dispersed patterns of use in the Sierra Nevada Wilderness, California

Natural resource managers are faced with a complex problem of understanding human use patterns and associated impacts in dispersed recreation wilderness settings. While conventional approaches to modelling have limited use in acquiring and understanding such complex associations, spatial simulation models have been proposed as an alternative. The purpose of this paper is to describe a project whose focus is on a dispersed recreation context of backpacking trips and commercial packstock operations in the John Muir Wilderness in the Sierra Nevada Mountains in California. This paper will discuss the data collection and synthesis to derive agent profiles and rules as a precursor to the development of a dynamic, agent based model that represents the spatial distribution of visitation patterns.     

Cycle of gonadal development in Eunicella singularis (Cnidaria: Octocorallia): trends in sexual reproduction in gorgonians

Abstract. Eunicella singularis is a gorgonian species whose members are abundant in hard-bottom sublittoral communities of the Mediterranean Sea. The reproductive biology in this species has been examined to better understand the ability in this species to recover from recent mass mortality events. Eunicella singularis is a stable, gonochoric, iteroparous species that reproduces annually and exhibits a seasonal pattern of gametogenesis characterized by a single annual maturation of the gametes. The sex ratio did not significantly differ from 1:1. Oogenesis lasted 13–17 months, beginning between February and June, and ending with the release of 0.7 planula larvae per polyp between late May and July of the following year. The diameter of mature oocytes ranged 450–860 μm. Spermatogenesis was much shorter than oogenesis and occurred over 5–6 months. Gonadal production of both sexes increased in spring and culminated with the spawning of male colonies in late May–June. Fertilization of oocytes and development of the planula larvae occurred within the polyps of female colonies. Planula release was observed in June and July. The patterns emerging from this and previous studies on sexual reproduction of Mediterranean gorgonians suggest that investment in gonad development appears to be related to resource availability.     

Endogenous hyperlactatemia and insulin secretion]

In the normal anesthetized dog, the endogenous hyperlactatemia induced either by intense muscular work or by a high dose of phenformin (20 mg/kg subtucaneously) is followed by an increase in the pancreaticoduodenal insulin output. A previous perfusion of sodium dichloroacetate (50 mg/kg. h) opposes the hyperlactatemia, and reduces or suppresses the increase in insulin output.