50 research outputs found
Rectal temperature in the first five hours after hypoxia-ischaemia critically affects neuropathological outcomes in neonatal rats
Electrospray ionization mass spectrometric detection of self-assembly of a crown ether complex directed by π-stacking interactions
Data-Dependent Middle-Down Nano-Liquid Chromatography–Electron Capture Dissociation-Tandem Mass Spectrometry: An Application for the Analysis of Unfractionated Histones
Development Of A Potentiometric Flow Cell With A Stainless Steel Electrode For Ph Measurements. Determination Of Acid Mixtures Using Flow Injection Analysis.
In this work a stainless steel electrode was prepared, characterised and used as indicator electrode in a potentiometric flow cell. Due to its versatility, it was possible to study different electrode geometries and flow cell arrangements. After optimising the system, mixtures of succinic and oxalic acids were determined by titration. Partial least squares (PLS) regression as multivariate calibration tool was applied for data treatment. The predicted results obtained in a test set showed a relative error of 4.3% for succinic acid and 5.5% for oxalic acid.511163-
A pre-formed Pyrogenic Factor Released by Lipopolysaccharide Stimulated Macrophages
The aim of this study was to investigate the pyrogenic activity of
factor(s) released by rat peritoneal macrophages following a brief
stimulation with LPS. The effect of this factor on the number of
circulating leukocytes and serum Fe, Cu and Zn levels, was also
evaluated. The possibility that the content of interleukin
(IL)-1β, IL-6 and tumour necrosis factor (TNF) in the
supernatant could explain the observations was investigated.
Supernatant produced over a period of 1 h by peritoneal macrophages,
following a 30 min incubation with LPS at 37°C, was
ultrafiltered through a 10 000 MW cut-off Amicon membrane,
sterilized, and concentrated 2.5, 5, 10 and 20 times. The
intravenous (i.v.) injection of this supernatant induced a
concentration-dependent fever in rats with a maximal response at 2
h. The pyrogenic activity was produced by macrophages elicited with
thioglycollate and by resident cells. The supernatants also induced
neutrophilia and reduction in Fe and Zn 6 h after the injection.
Absence of activity in boiled supernatants, or supernatants from
macrophages incubated at 4°C with LPS, indicates that LPS was
not responsible for the activity. In vitro treatment
with indomethacin (Indo), dexamethasone (Dex), or cycloheximide
(Chx) did not modify the release of pyrogenic activity into the
supernatant or its effects on the reduction in serum metal levels.
Although Chx abolished the production of mediator(s) inducing
neutrophilia, and Dex reduced the induction of IL-1β, TNF and
IL-6, injection of the highest concentration of these cytokines
detected in the supernatants did not induce fever. In
vivo treatment with Dex, but not Indo, abolished the fever
induced by the supernatant. These results suggest that macrophages
contain pre-formed pyrogenic mediator(s), not related to IL-1β,
IL-6 or TNF, that acts indirectly and independently of
prostaglandtn. It also seems likely that the pyrogenic activity is
related to the factor responsible for the reduction of serum Fe and
Zn levels, but not the neutrophilia
Receptor deorphanization in an echinoderm reveals kisspeptin evolution and relationship with SALMFamide neuropeptides
Background: Kisspeptins are neuropeptides that regulate reproductive maturation in mammals via G-protein-coupled receptor-mediated stimulation of gonadotropin-releasing hormone secretion from the hypothalamus. Phylogenetic analysis of kisspeptin-type receptors indicates that this neuropeptide signaling system originated in a common ancestor of the Bilateria, but little is known about kisspeptin signaling in invertebrates.
Results: Contrasting with the occurrence of a single kisspeptin receptor in mammalian species, here, we report the discovery of an expanded family of eleven kisspeptin-type receptors in a deuterostome invertebrate — the starfish Asterias rubens (phylum Echinodermata). Furthermore, neuropeptides derived from four precursor proteins were identified as ligands for six of these receptors. One or more kisspeptin-like neuropeptides derived from two precursor proteins (ArKPP1, ArKPP2) act as ligands for four A. rubens kisspeptin-type receptors (ArKPR1,3,8,9). Furthermore, a family of neuropeptides that act as muscle relaxants in echinoderms (SALMFamides) are ligands for two A. rubens kisspeptin-type receptors (ArKPR6,7). The SALMFamide neuropeptide S1 (or ArS1.4) and a ‘cocktail’ of the seven neuropeptides derived from the S1 precursor protein (ArS1.1-ArS1.7) act as ligands for ArKPR7. The SALMFamide neuropeptide S2 (or ArS2.3) and a ‘cocktail’ of the eight neuropeptides derived from the S2 precursor protein (ArS2.1-ArS2.8) act as ligands for ArKPR6.
Conclusions: Our findings reveal a remarkable diversity of neuropeptides that act as ligands for kisspeptin-type receptors in starfish and provide important new insights into the evolution of kisspeptin signaling. Furthermore, the discovery of the hitherto unknown relationship of kisspeptins with SALMFamides, neuropeptides that were discovered in starfish prior to the identification of kisspeptins in mammals, presents a radical change in perspective for research on kisspeptin signaling
Receptor deorphanization in an echinoderm reveals kisspeptin evolution and relationship with SALMFamide neuropeptides
Background: kisspeptins are neuropeptides that regulate reproductive maturation in mammals via G-protein-coupled receptor-mediated stimulation of gonadotropin-releasing hormone secretion from the hypothalamus. Phylogenetic analysis of kisspeptin-type receptors indicates that this neuropeptide signaling system originated in a common ancestor of the Bilateria, but little is known about kisspeptin signaling in invertebrates.Results: contrasting with the occurrence of a single kisspeptin receptor in mammalian species, here, we report the discovery of an expanded family of eleven kisspeptin-type receptors in a deuterostome invertebrate — the starfish Asterias rubens (phylum Echinodermata). Furthermore, neuropeptides derived from four precursor proteins were identified as ligands for six of these receptors. One or more kisspeptin-like neuropeptides derived from two precursor proteins (ArKPP1, ArKPP2) act as ligands for four A. rubens kisspeptin-type receptors (ArKPR1,3,8,9). Furthermore, a family of neuropeptides that act as muscle relaxants in echinoderms (SALMFamides) are ligands for two A. rubens kisspeptin-type receptors (ArKPR6,7). The SALMFamide neuropeptide S1 (or ArS1.4) and a ‘cocktail’ of the seven neuropeptides derived from the S1 precursor protein (ArS1.1-ArS1.7) act as ligands for ArKPR7. The SALMFamide neuropeptide S2 (or ArS2.3) and a ‘cocktail’ of the eight neuropeptides derived from the S2 precursor protein (ArS2.1-ArS2.8) act as ligands for ArKPR6.Conclusions: our findings reveal a remarkable diversity of neuropeptides that act as ligands for kisspeptin-type receptors in starfish and provide important new insights into the evolution of kisspeptin signaling. Furthermore, the discovery of the hitherto unknown relationship of kisspeptins with SALMFamides, neuropeptides that were discovered in starfish prior to the identification of kisspeptins in mammals, presents a radical change in perspective for research on kisspeptin signaling