Publications by authors named "CHIEFFI G"

This paper reports the continuous reductive amination of different molecules, including biomass-related compounds, over carbon-supported FeNi nanoparticles obtained on the basis of inexpensive and abundant metal precursors and cellulose. A biorefinery case study for the preparation of pyrrolidones via acid-catalyzed hydrolysis of glucose followed by reductive amination of the obtained levulinic acid is described.

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PATZ1 is a recently discovered zinc finger protein that, due to the presence of the POZ domain, acts as a transcriptional repressor affecting the basal activity of different promoters. To gain insights into its biological role, we generated mice lacking the PATZ1 gene. Male PATZ1(-/-) mice were unfertile, suggesting a crucial role of this gene in spermatogenesis.

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The rat exorbital lacrimal glands (ELG) are particularly interesting for their biochemical and morphological sexual differences. Our histochemical and ultrastuctural observations confirm a phenomenon termed "harderianization" that occurs in the ELG of males and females at three months of age. The "harderianization" consists of the appearance of lipid foci in the ELG; this effect increases at six months of age only in the male glands, while it is not detectable in those of females.

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The hamster Harderian gland (HG), a compound tubuloalveolar gland located in the orbital cavity, displays sex dimorphism. The present study focuses on the sequence analysis of a cDNA clone named MHG07 and on the regulation of its expression by steroid hormones. MHG07 mRNA (5.

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The Harderian gland of the gecko, Tarentola mauritanica, was studied at the histological, histochemical, and ultrastructural levels. It is a nonlobate compound acinar gland surrounded by a thin capsule of connective tissue. Numerous connective tissue-type mast cells, ultrastructurally similar to those described in other higher vertebrates, were identified in the interstitial tissue between the acini.

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The Harderian gland of the terrapin Pseudemys scripta has four types of acinar cells. Type IV cells are very similar to the salt secreting cells of the salt secretory glands of various marine vertebrates. The presence and localization of the Ile5-Angiotensin II, Atrial Natriuretic Peptide, and Bradykinin has been investigated by immunohistochemical methods.

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The harderian gland is an orbital gland of the majority of land vertebrates. It is the only orbital gland in anuran amphibians since the lacrimal gland develops later during phylogenesis in some reptilian species. Perhaps because it is not found in man, little interest was paid to this gland until about four decades ago.

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Polyacrylamide gel electrophoresis (PAGE) of proteins with subsequent western blotting has become a routine technique for the analysis of proteins from both cultured cells and fresh whole tissue. We have developed a method to extract proteins from methacarn-fixed tissue which renders them suitable for SDS-PAGE and western blotting. With a panel of antibodies to specific intermediate filaments, transforming growth factor-alpha (TGF-alpha), and albumin, immunohistochemistry was performed in parallel with western blotting on sections cut from methacarn-fixed samples of normal rat liver and liver from rats treated under a regime which induces oval cell proliferation.

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Day-night variations of melatonin content and N-acetyltransferase (NAT) activity were studied in the Harderian gland (HG), retina, pineal gland, and serum of the green frog Rana esculenta. Throughout the year the retinal melatonin content was correlated with retinal NAT activity and was always higher than those in the pineal gland and HG. On the other hand, in these structures diurnal fluctuations in NAT activity were observed.

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The Zoological Station of Naples was founded in 1872 by Anton Dohrn as a research institute for zoology and comparative anatomy. Although the original fields of interest were the morphology of vertebrates and comparative embryology, a department of physiology was added to the station in 1888. Osmoregulation in marine organisms has been extensively studied, notably by Bottazzi, who investigated chemical composition, electrical conductivity, surface tension, osmotic pressure and extracellular viscosity in circulating fluids in man and lower animals.

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Changes of RNA synthesis were demonstrated in neurons and ependymal cells of the green frog Rana esculenta during the annual cycle using the Mallory's trichrome stain as histochemical marker and autoradiography. Since the higher affinity of the nuclei for aniline blue is consistent with the increase of RNA content, the increase of RNA synthesis was expressed as percentage of the blue stained nuclei (% BSN). Neuronal transcription starts slowly in March or April, reaches a maximum in July and declines from September to November or December, depending on the brain region.

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1. Sodium dodecyl sulphate 7-12% gradient polyacrylamide gel electrophoresis of male and female hamster Harderian gland whole homogenate shows a clear-cut sexual dimorphism, which consists of the presence of two male-specific glycoproteins (168 and 116 kDa) and two specific female proteins (210 and 190 kDa). 2.

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1. The effect of a single injection of ethane-1,2-dimethane sulfonate (EDS) was studied in the teleost fish, Gobius paganellus in two different periods of the year. 2.

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Follicular atresia was studied in the ovary of the electric ray, Torpedo marmorata, by light and electron microscopy. The course of atresia may be divided into four stages. The first two comprise the dissolution of the oocyte and its phagocytosis by the small cells of the granulosa epithelium.

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The role of androgens in the cyclic secretory activity of the Rana esculenta Harderian gland (HG) was studied. Total RNA showed a dramatic increase in October and May when the nuclear androgen receptors peak. During the resumption of the secretory activity a gradual increase of poly(A)(+)-RNA was detected; during the enhancement phase (May) a peak of the poly(A)(+)-RNA fraction was found.

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Steroid concentrations in plasma and follicular tissues (theca plus granulosa layers) were determined by radioimmunoassay in the aplacental viviparous ray, Torpedo marmorata, during various stages of the reproductive cycle. Steroids in the uterine fluid of pregnant animals and in preovulatory atretic follicles were also measured. In the follicular tissue of cyclic animals, levels of progesterone were always lower than those of estradiol-17 beta and androgens (testosterone plus 5 alpha-dihydrotestosterone).

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When Mallory's trichrome stain is used, acinar nuclei of the Harderian gland of Rana esculenta display different affinities for the dye. Some of the orangiophilic nuclei show affinity for aniline blue (blue nuclei). In the Harderian gland of Rana esculenta their number and the intensity of staining with aniline blue may vary during the year.

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An androgen receptor has been identified in the cytosolic and nuclear extracts of the Harderian gland of the frog, Rana esculenta. A single class of high-affinity binding sites was found: Kd = 1.9 +/- 1.

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Seasonal variations of intratesticular steroid hormones (androgens and estradiol-17 beta) and spermatogenic activity have been studied in the marine teleost fish, Gobius paganellus. In addition, in vivo and in vitro experiments have been carried out in order to investigate the control of androgen production by the testis. While estradiol was never detected, androgens were at low values in autumn and reached maximal levels in spring concomitantly with the highest testis weight and the highest efficiency of the spermatogenic wave.

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The possible physiological role of a putative testicular gonadotropin-releasing hormone (GnRH)-like material was studied in the frog, Rana esculenta. We have investigated (a) changes of mitotic index (MI) of primary spermatogonia (SPG) in GnRH agonist (GnRH-Ag)-treated testes in vitro; (b) changes of androgen concentrations in testes of intact frogs treated with a GnRH antagonist (GnRH-Ant); (c) variations of mitotic index of primary SPG in intact GnRH-Ant-injected animals and in testes incubated with GnRH-Ant; (d) changes of MI in hypophysectomized (PDX) animals treated with hypophysis (PD) homogenate, and hCG alone or in combination with GnRH-Ant; and (e) changes of androgen concentrations in plasma PDX frogs treated with hCG and hCG plus GnRH-Ant. Our results indicate that while GnRH-Ag induced accumulation of primary SPG mitosis, GnRH-Ant inhibited androgen production and natural occurring mitosis accumulation.

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Frog, Rana esculenta, pituitary and testis gonadotropin-releasing hormone (GnRH) receptors were characterized by using 125I-chicken IIGnRH (cIIGnRH) as radiolabeled ligand. At 4 C equilibrium binding of 125I-cIIGnRH to pituitary homogenates was achieved after 90 min of incubation; binding of 125I-cIIGnRH to testis membrane fractions reached its maximum at 60 min of incubation. Binding of the radioligand was a function of tissue concentration, with a positive correlation over the range 0.

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Histology, histochemistry, and ultrastructure of the Harderian gland and lacrimal gland of the lizard Podarcis s. sicula were investigated. The Harderian gland, located at the medial corner of the orbit, can be divided into three zones showing different tinctorial features either with Mallory or hematoxylineosin stains.

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1. The secretory activity of the Harderian gland in Rana esculenta varies during the year, reaching its highest activity during the hottest period (July-August). Therefore, secretion may be modulated by temperature and/or photoperiod.

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The effect of a gonadotropin-releasing hormone analog (GnRHA, HOE766) was studied in hypophysectomized elasmobranch fish Torpedo marmorata and T. ocellata. In addition, estradiol (E2) effects were studied in intact and hypophysectomized (HPX) animals.

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