Mania in children.
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Attention Deficit Disorder with Hyperactivity↗
Biomedical subjects
G Pelletier
Publications and source records attributed to G Pelletier.
Localization and regulation of expression of the FAR-17A gene in the hamster flank organs.
A quantitative in situ hybridization study was carried out to determine the precise localization and androgen regulation of the flank organ regulated (FAR-17A) mRNA expression in the different cellular components of the hamster flank organs. Although FAR-17A mRNA was highly expressed in the epithelial cells of the sebaceous glands, it was also found in the outer root sheath of the hair follicles and in melanocytes. The changes in FAR-17A mRNA levels, in the size of the flank organ and sebaceous gland areas as well as in the weight of the seminal vesicles and prostate, were compared following castration and after 5alpha-dihydrotestosterone treatment. FAR-17A mRNA levels were already significantly decreased 1 d after castration, in parallel with a concomitant decrease in the number of labeled cells with the FAR-17A probe. A maximal decrease was found 7 d after castration. The other parameters were significantly reduced later. After 7 d of treatment with dihydrotestosterone, all values returned to those found in intact animals. Similar stimulatory effects on these parameters were observed after treatment with the adrenal sex steroid precursor dehydroepiandrosterone. These data show that all of the components of the flank organs (sebaceous glands, hair follicles, and melanocytes) express the flank organ regulated (17A) type gene (FAR-17A) gene and that its expression is stimulated by treatment with either dihydrotestosterone or dehydroepiandrosterone. Moreover, FAR-17A mRNA levels respond to androgen stimulation more rapidly than the standard morphologic parameters, revealing that the FAR-17A gene could be a more sensitive and cell specific marker to study the mechanisms of androgen action in the skin.
Androgens↗
Pig pancreatic acinar cells possess predominantly the CCK-B receptor subtype.
Studies performed on pig indicated that its pancreas was insensitive to the gastrointestinal hormone cholecystokinin (CCK) and suggested that its secretions were rather under the control of the neurotransmitter acetylcholine. This study was performed to determine reasons for this insensitivity by comparing secretory responses to different secretagogues and establishing the dominant CCK receptor type. Pancreatic acini prepared from weaned piglets were evaluated for their sensitivity to carbamylcholine (Cch), caerulein, JMV-180, and secretin. RNA were extracted for CCK-A and CCK-B receptor expression using specific cRNA probes. Results indicate that pig pancreatic acini are sensitive to Cch and relatively insensitive to caerulein with no response to JMV-180, a CCKA agonist, or secretin; MK-329, a CCK-A receptor antagonist, significantly inhibited caerulein-induced enzyme secretion from 10(-8) M. The pig pancreas expresses few CCK-A mRNA receptors but a majority of CCK-B. These data demonstrate that the pig pancreas expresses a majority of CCK-B receptors. In conclusion, the pig pancreas possesses a large majority of CCK-B receptors responsible for their low sensitivity to CCK.
Amylases↗
Further studies on the mechanism of action of the endogenous benzodiazepine receptor ligand octadecaneuropeptide on gonadotropin-releasing hormone gene expression in the rat brain.
We have recently reported that the intracerebroventricular injection of the endogenous benzodiazepine (BZD) receptor ligand octadecaneuropeptide (ODN) (30 micrograms/kg b.w.) could induce a decrease in gonadotropin-releasing hormone (GnRH) mRNA levels in the male rat brain. This inhibitory effect could be completely reversed by the concomitant administration of the GABAA antagonist picrotoxin. In order to further investigate the mechanism of action of ODN, we investigated the effects of intracerebroventricular injection of a smaller dose of ODN (3 micrograms/kg b.w.) and the influence of the GABAA receptor agonist muscimol and the antagonist to BZD receptors flumazenil on GnRH gene expression. Treatment with ODN induced a 40% decrease in mRNA levels, an effect which was potentiated by the concomitant administration of muscimol. The administration of flumazenil produced a small increase in GnRH mRNA while the inhibitory effect of ODN on GnRH mRNA levels was completely prevented by the administration of this BZD antagonist. Moreover, the intravenous administration of increasing doses of ODN also induced a marked decrease of 33, 32 and 38% for 75, 150 and 300 micrograms/kg b.w., an effect which was completely abolished by picrotoxin. These data clearly indicate that an endogenous neuropeptide can activate the GABAA BZD receptor complex to negatively modulate the activity of GnRH neurons. They also suggest that this peptide or other endogenous activators of the GABAA BZD receptors might exert a tonic inhibitory influence on GnRH gene expression.
Animals↗
Successful multimodal treatment of a child with selective mutism: a case report.
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Child↗
Development of GP-2 and five zymogens in the fetal and young pig: biochemical and immunocytochemical evidence of an atypical zymogen granule composition in the fetus.
To uncover the mechanisms involved in the biogenesis of secretory granules, we studied development of the exocrine pancreas in the pig from the fetus up to the mature animal by following the enzyme activities and expression (Northern blot) of five zymogens and GP-2, the major protein of the granule membrane. Fetal pancreas mainly contained chymotrypsinogen and barely detectable amounts of amylase, trypsin, lipase, and elastase. GP-2 was not notably expressed before the Day 21 of life. Ultrastructural examination of the fetal tissue embedded in Epon with osmium postfixation or in Lowicryl at -20 degrees C without postfixation showed dense granules with an irregular shape but also showed that most granules had uncondensed contents, with the aspect of immature granules, or had a dense core surrounded by light material. With immunogold cytochemistry, the concentration of chymotrypsinogen was directly associated with the acquisition of electron density by the granule matrix. These observations suggest that fetal granules have a slower rhythm of zymogen condensation and an irregular shape that could be due to the particular composition of the matrix and the absence of GP-2. We conclude that, in the exocrine pancreas, secretory granules can be formed under various conditions, even with a matrix containing a ratio of components very different from that of the normal mature animal.
Animals↗
Localization of gamma-aminobutyric acid and glutamic acid decarboxylase in the pancreas of the nonobese diabetic mouse.
Glutamic acid decarboxylase (GAD), among other potential autoantigens, is thought to play a crucial role in type I diabetes, particularly in a spontaneous model of the disease, the nonobese diabetic (NOD) mouse. In the pancreas, the presence of GAD and gamma-aminobutyric acid (GABA), the decarboxylation product of GAD and a putative neurotransmitter in the islets of Langerhans, is well documented in the beta-cells. This is particularly true in rats, in which another GABAergic structure exists near the islets, the neuronal bodies. In this study, first the GABA content was measured in isolated islets from NOD and C57BL/6 mice (controls), and a decrease was found in NOD females as their insulitis progressed. Second, for the first time in mice, confocal analysis of immunofluorescent-labeled pancreatic sections revealed near the islets neuronal structures in which GAD and neuropeptide Y were colocalized, as they are in the brain. These structures were always observed in the pancreata of both sexes of C57BL/6 mice at the various ages investigated. In NOD mice, however, these neuronal structures were only detected in young females ( < 10 weeks old) and in males until an intermediate age. Moreover, patches of T cells surrounding GAD-containing fibers were seen in the vicinity of the islets with incipient periinsulitis.
Animals↗
Gene expression of interleukin-2 in purified human peripheral blood eosinophils.
To verify the hypothesis that eosinophils produce interleukin-2 (IL-2), a cytokine essential for lymphocyte activation, the expression of IL-2 was examined in peripheral blood eosinophils obtained from normal, atopic, asthmatic and hypereosinophilic subjects. Purified blood cell preparations were > 95% eosinophils, the remaining cells being neutrophils. Based on morphological observations and on CD3 expression, no lymphocytes were detected in these eosinophil preparations. The expression of IL-2 mRNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR) in total RNA extracted from purified eosinophils stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF), with or without calcium ionophore (A23187). In-cell RT-PCR combined with in situ hybridization further confirmed that it was the eosinophils that expressed IL-2 mRNA. Moreover, in this experiment IL-2 mRNA expression increased upon costimulation with A23187 and GM-CSF suggesting that a steady-state level of IL-2 mRNA was inducible. Finally, IL-2 was detected in purified eosinophils by immunochemistry. These data, obtained by different techniques, demonstrate that eosinophils can express IL-2. An IL-2-mediated eosinophil-lymphocyte interaction could contribute to the chronic state of cell activation in inflamed tissues where these cells are implicated.
Asthma↗
[Does expression of the proopiomelanocortin (POMK) gene occur in magnocellular (nonapeptidergic) nuclei of the rat hypothalamus?].
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Animals↗
Immunocytochemical localization of type I 17 beta-hydroxysteroid dehydrogenase in the rat brain.
Type I 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) is mainly involved in the reductive transformation of estrone to estradiol. Such a conversion is known to occur in mammalian brain. In order to determine the brain areas and the nerve cell types containing this enzyme, we have proceeded to its immunocytochemical localization in the adult rat brain. Immunoblot analysis showed that the antibodies used could specifically bind to one brain protein band corresponding to purified 17 beta-HSD. Immunolabelled cells were found in high concentration in the hypothalamus, thalamus, hippocampus, cerebral cortex, caudate putamen and pineal gland. At the light microscopic level, 17 beta-HSD immunoreactive material appeared to be present only in glial and ependymal cells, including tanycytes. Double staining procedures showed that the 17 beta-HSD nerve cells also contained glial fibrillary acidic protein (GFAP), a specific marker for glial cells. Immunoelectron microscopic studies demonstrated that immunoreactive material was diffusely distributed throughout the cytoplasm of glial and ependymal cells, thus confirming the association of 17 beta-HSD immunoreactivity with nonneuronal cells. These data suggest that glial cells play an important role in the conversion of a weak estrogen, estrone, to a more potent estrogen, estradiol.
17-Hydroxysteroid Dehydrogenases↗
Induction of apoptosis by excessive polyamine accumulation in ornithine decarboxylase-overproducing L1210 cells.
Deregulation of polyamine transport in L1210 cells overexpressing ornithine decarboxylase leads to a lethal accumulation of spermidine. We now provide evidence that over-accumulation of natural and synthetic polyamines, but not putrescine, rapidly induces apoptosis, as shown by hypercondensation of peripheral chromatin and internucleosomal cleavage, followed by nuclear fragmentation. Polyamine oxidation is not responsible for the apoptosis observed. Thus, abnormally high polyamine pools could be an important physiological trigger of apoptosis.
Animals↗
Inhibitory effect of the potential endogenous benzodiazepine receptor ligand, octadecaneuropeptide (ODN), on gonadotropin-releasing hormone gene expression in the male rat brain.
It has been reported that activation of the GABAA receptor complex by different agents such as barbiturates and neurosteroids can negatively regulate the hypothalamopituitary-gonadal axis. Recently, an 86-amino acid polypeptide with high affinity for diazepam binding sites, termed diazepam-binding inhibitor (DBI), has been found in the rat brain. DBI as well as a peptide derived from DBI, the octadecaneuropeptide DBI[33-50] (ODN), can interact with the GABAA receptor complex. In order to investigate the role of these endogenous ligands for GABAA receptors on GnRH gene expression, we studied the effects of the acute administration (4 h before sacrifice) of ODN injected alone or in combination with the GABAA agonist muscimol on GnRH mRNA levels. Treatment with ODN produced a 31% decrease in the number of silver grains overlying labelled neurones. This effect was not modified by the concomitant administration of muscimol. The administration of the GABAA antagonist picrotoxin not only reversed the inhibitory effect of ODN but induced a 24% increase in the hybridization signal. This stimulating influence of picrotoxin was less striking (15% over control levels) when muscimol was administered with ODN. These data clearly indicate that a potential endogenous neuropeptide can positively interact with the GABAA receptor complex to modulate GnRH neuronal activity.
Animals↗
Neuropeptide tyrosine in the brain of the African lungfish, Protopterus annectens: immunohistochemical localization and biochemical characterization.
Lungfishes, which share similarities with both fishes and amphibians, represent an interesting group in which to investigate the evolutionary transition from fishes to tetrapods. In the present study, we have investigated the localization and biochemical characteristics of neuropeptide Y (NPY)-immunoreactive material in the central nervous system of the African lungfish, Protopterus annectens. NPY-immunoreactive cell bodies were found in various regions of the brain, most notably in the telencephalon (septal area, ventral striatum, and nucleus accumbens), in the diencephalon (preoptic nucleus, periventricular region of the hypothalamus, and ventral thalamus), and in the tegmentum of the mesencephalon. A strong immunoreaction was also detected in cell bodies of the nervus terminalis. Immunoreactive nerve fibers were particularly abundant in the ventral striatum, the nucleus accumbens, the diagonal band of Broca, the hypothalamus, and the mesencephalic tegmentum. Positive fibers were also seen in the median eminence and in the neural lobe of the pituitary. The NPY-immunoreactive material localized in the brain and pituitary was characterized by combining high-performance liquid chromatography (HPLC) analysis and radioimmunological quantitation. The displacement curves obtained with synthetic porcine and frog NPY and serial dilutions of brain and pituitary extracts were parallel. Reversed-phase HPLC analysis of telencephalon, diencephalon, and pituitary extracts resolved a major NPY-immunoreactive peak that coeluted with frog NPY. The similarity between the distribution of NPY-containing neurons and the biochemical characteristics of the immunoreactive peptide in the brain of lungfish and frog strongly favors a close phylogenetic relationship between dipnoans and amphibians.
Animals↗
Involvement of the Y2 receptor subtype in the regulation of prolactin gene expression by neuropeptide Y in the male rat.
In order to determine the influence of neuropeptide Y (NPY) on the biosynthesis of prolactin (PRL), we have studied the effects of NPY and some NPY analogs on PRL gene expression in the male rat anterior pituitary gland. The following peptides (4 micrograms/100 g body wt): NPY, peptide YY (PYY), NPY13-36 (a Y2 receptor agonist) and [Leu31,Pro34]NPY (a Y1 receptor agonist) were injected into the left lateral ventricle of adult male rats. Control animals received only the vehicle (0.9% NaCl). All the animals were perfused with 4% paraformaldehyde 4 h after injection and processed for in situ hybridization. The intracerebroventricular injection of NPY, PYY, and NPY13-36 induced a significant increase in the hybridization signal (22-40% over control). On the other hand, the Y1 receptor agonist [Leu31,Pro34]NPY did not influence PRL mRNA levels. These data then suggest that activation of the Y2 NPY receptor subtype at the central level can positively regulate PRL gene expression.
Animals↗
Regulation of proopiomelanocortin gene expression by neuropeptide Y in the rat arcuate nucleus.
In the arcuate nucleus which is richly innervated by both proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons, it has been shown that NPY fibers are in synaptic contact with POMC cell bodies. In order to determine whether NPY could influence POMC neuronal activity, we have studied the effects of NPY and some NPY analogs on POMC gene expression using quantitative in situ hybridization. The following peptides NPY, [Leu31,Pro34]-NPY (a Y1 receptor agonist), and NPY13-36 (a Y2 receptor agonist) were injected into the left lateral cerebral ventricle of adult male rats 4 h before being perfused for histological procedures. The intracerebroventricular injection of NPY and NPY13-36 induced a significant decrease in the number of grains overlying the labelled neurons. On the other hand, the Y1 receptor agonist [Leu31,Pro34]-NPY did not modify POMC mRNA levels. These data then strongly suggest that NPY negatively regulates the genetic expression of POMC neurons via the Y2 NPY receptor subtype.
Animals↗
[Medical treatment of chronic viral hepatitis].
alpha-interferon and vidarabine monophosphate are currently available for the treatment of chronic active hepatitis B. Treatment is indicated in patients with high transaminase levels, evidence of replicating virus and histological inflammation. Interferon or vidarabine suppress viral replication and normalize transaminase activity in 30 to 40% of the patients. The main predictive factors of response to therapy are a high transaminase level, a low replication level, and the absence of immunodepression. The response is usually sustained and the Ag HBs to anti-HBs seroconversion occurs a few years after treatment. No efficacious treatment is still available in patients with chronic hepatitis D. Standard treatment of chronic hepatitis C with alpha-interferon (3 millions units 3 times a week during 6 months) induces a complete response in only 15% of the patients. New modalities of interferon therapy and associated treatment are currently evaluated.
Chronic Disease↗
The radiosensitivity of uveal melanoma cells and the cell survival curve.
BACKGROUND: No study of the radiosensitivity of uveal melanoma cells and their survival curve has been published. The purpose of this study was to investigate the sensitivity to different single radiation doses of SP6.5, a human uveal melanoma cell line. METHODS: Cells were irradiated with cobalt-60 at doses from 0 to 1200 cGy. Radiosensitivity was measured by three methods: soft-agar bilayer assay, tritiated thymidine incorporation, and bromodeoxyuridine (BrdU) incorporation. RESULTS: The soft-agar bilayer assay, by assessing the colony-forming units, showed that the D1 value was 470 cGy, the Dq value was 400 cGy, and the n value exceeded 10, thus indicating a broad, shoulder and relative radioresistance. The doubling time as estimated by [3H]thymidine incorporation was unaffected at doses below 600 cGy, another indication of radioresistance. BrdU incorporation revealed no significant increase between 0 and 1000 cGy, indicating that the cell cycle was not interrupted. CONCLUSION: Cell survival, doubling time, and cell phases are parameters of growth kinetics, and the results suggest that SP6.5 is radioresistant and virtually unaffected by single radiation doses lower than 600 cGy. Our data parallel published data for cutaneous melanomas.
Aged↗