Increased atrial natriuretic peptide (6-33) binding sites in the subfornical organ of water deprived and Brattleboro rats

Binding sites for rat atrial natriuretic peptide (6-33) (ANP) were quantitated in the subfornical organ of chronically dehydrated homozygous Brattleboro rats unable to synthesize vasopressin; heterozygous Brattleboro rats, their controls, Long Evans rats and Long Evans rats after 4 days of water deprivation. Brain sections were incubated in the presence of 125I-ANP and the results analyzed by autoradiography coupled to computerized microdensitometry and comparison to 125I-standards. Brattleboro rats and water deprived Long Evans rats presented a higher number of ANP binding sites than their normally hydrated controls. Our results suggest a role of ANP binding sites in the subfornical organ in the central regulation of fluid balance and vasopressin secretion.     

Localization of atrial natriuretic peptide, ANP-(99-126) binding sites in the rat thymus and spleen with quantitative autoradiography

Binding sites for atrial natriuretic peptide, ANP-(99-126) were studied in lymphoid organs of the rat with quantitative autoradiography. Tissue sections were incubated in the presence of 0.13 nM 125I-ANP-(99-126) followed by autoradiography using [3H]-Ultrofilm, and the results were analyzed by computerized densitometry and comparison to 125I-standards. Specific ANP binding sites were localized in the medulla and the cortex of the rat thymus and in the white pulp of the rat spleen, with apparent binding sites concentrations of 93, 65, and 126 fmol/mg protein, respectively. The presence of ANP binding sites in areas related to the maturation and function of lymphocytes, and to the production of thymic hormones, suggests the possibility of a role of circulating ANP in the modulation of the immune response.     

Degeneration in the parvocellular portion of the lateral geniculate nucleus of the cebus monkey

Summary The synaptology of the Cebus lateral geniculate nucleus (LGN) was studied after varying (3–15 days) periods of survival following unilateral and bilateral eye enucleations. Part of the material was processed with the Glees and Nauta techniques for light microscopy while the rest was processed for electron microscope observation. The study revealed a variety of degenerated terminals in the parvocellular portion of the LGN and allowed the differentiation of the retinal from the extraretinal terminals. The most frequent synaptic type of retinal origin is a glomerular large central terminal (up to 20 long) which makes axodendritic and axoaxonic synaptic contacts with geniculate dendrites and peripheral small terminals. Simple axodendritic and axosomatic terminals of retinal and extraretinal origin were also found. The early changes affecting the geniculate neurons and astrocytes during the degenerative process are described.These results are discussed in relation to: 1) previous work on the LGN synaptology of cats and macaques; 2) the physiology of the LGN; 3) the phagocytic role of astrocytes; 4) the general problem of degeneration in the central nervous system. In addition, a correlation between the light and electron microscope observations is attempted.Work supported by Grants from the National Council to Combat Blindness, Inc. N.Y., U.S.A. (Fight for Sight Grant-in-Aid-G-340), the AF-AFOSR Grant No. 963/67-68, and the Consejo Nacional de Investigaciones Cientificas y Técnicas, Buenos Aires, Argentina.The authors acknowledge the continuous advice and encouragement received from Prof. E. de Robertis throughout all the phases of the project. The expert technical assistance of Miss E. di Matteo, Mr. A. Sáenz and Mr. R. Castelli is also gratefully acknowledged.     

Further studies on the understanding of Octodon degus natural resistance to morphine: a comparative study with the Wistar rat

1. Octodon degus shows higher levels of tolerance to morphine when compared with the Wistar rat. 2. In the formalin algesiometric test, this caviomorph is more resistant to pain (P less than 0.01) and to the analgesic effect of morphine (P less than 0.001). 3. CD50 and LD50 were significantly higher in Octodon degus as compared with Wistar rat. 4. Morphine caused in rat severe hypotension, while doses eight times higher in O. degus had a transient effect. 5. 3H-naloxone binding in adrenal glands of O. degus is higher than in other tissue samples assayed from the same animal or rats.     

The results of 2-year pollen monitoring of an urban network in Perugia,Central Italy

Continuous pollen monitoring of an urban network consisting of three stations has been undertaken for a period of 2 years in Perugia, central Italy. The aim has been to establish whether the Perugia pollen trap, active since 1983, is still representative of the area following recent urbanisation. Quantitative differences were found between the stations, reflecting different vegetational areas, but only slight differences were detected in relation to the timing of the principal period of pollination. Therefore, although individual pollen traps are necessary to characterize fully the different areas, one trap is sufficient to determine the key allergenic thresholds in the studied area.     

The results of 2-year pollen monitoring of an urban network in Perugia,Central Italy

Continuous pollen monitoring of an urban network consisting of three stations has been undertaken for a period of 2 years in Perugia, central Italy. The aim has been to establish whether the Perugia pollen trap, active since 1983, is still representative of the area following recent urbanisation. Quantitative differences were found between the stations, reflecting different vegetational areas, but only slight differences were detected in relation to the timing of the principal period of pollination. Therefore, although individual pollen traps are necessary to characterize fully the different areas, one trap is sufficient to determine the key allergenic thresholds in the studied area.     

Differential IAA dose response relations of the axr1 and axr2 mutants of Arabidopsis

In comparison to wild type Arabidopsis thaliana, the auxin resistant mutants axr1 and axr2 exhibit reduced inhibition of root elongation in response to auxins. Several auxin-regulated physiological processes are also altered in the mutant plants. When wild-type, axr1 and axr2 seedlings were grown in darkness on media containing indoleacetic acid (IAA), promotion of root growth was observed at low concentrations of IAA (10^?11 to 10^?7M) in 5-day-old axr2 seedlings, but not in axr1 or wild-type seedlings. In axr1 there was little or no measurable root growth response over the same concentration range. In wild type, root growth was inhibited at concentrations greater than 10^?10M and no detectable root growth response was observed at lower concentrations. In addition, production of lateral roots in response to IAA increased in axr2 seedlings and decreased in axr1 seedlings relative to wild type. Promotion of root elongation and initiation of lateral roots in axr2 seedlings in response to auxin indicate that axr2 seedlings are able to perceive and respond to IAA.     

Impacts of introduced common wasps (Vespula vulgaris) on experimentally placed mealworms in a New Zealand beech forest

An introduced social wasp Vespula vulgaris may compete with native birds for honeydew and invertebrates in New Zealand forests. Experimentally hidden mealworms (Tenebrio molitor) persisted longer at two sites following wasp poisoning that at two sites where wasps were not poisoned. Mealworms persisted longer in the morning than in the afternoon within all study sites. An unusually low mealworm removal rate during a morning trial before wasp poisoning heavily influences the results of this experiment but we have no ecological reason to ignore it. Wasps may therefore be having a heavy impact on invertebrate abundance on very short time scales (within a day following dawn emergence). They may also remove cached food items that would otherwise be retrieved by the South Island robin (Petroica australis australis) during cold or dark feeding conditions.     

Keratinocyte growth factor

Keratinocyte growth factor (KGF) is a member of the heparin-binding fibroblast growth factor family (FGF-7) with a distinctive pattern of target-cell specificity. Studies performed in cell culture suggested that KGF was mitogenically active only on epithelial cells, albeit from a variety of tissues. In contrast, KGF was produced solely by cells of mesenchymal origin, leading to the hypothesis that it might function as a paracrine mediator of mesenchymal-epithelial communication. Biochemical analysis and molecular cloning established that the KGF receptor (KGFR) was a tyrosine kinase isoform encoded by the fgfr-2 gene. Many detailed investigations of KGF and KGFR expression in whole tissue and cell lines largely substantiated the pattern initially perceived in vitro of mesenchymal and epithelial distribution, respectively. Moreover, functional assays in organ culture and in vivo and studies of KGF regulation by sex sterorid hormones reinforced the idea that KGF acts predominantly on epithelial cells to elicit a variety of responses including proliferation, migration and morphogenesis.