Completeness of beta-phase decomposition reaction in Cu-Al-Ag alloys

The completeness of beta-phase decomposition reaction in the Cu-11wt%Al-xwt%Ag alloys (x = 0, 1, 2, and 3) was studied using differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and optical microscopy (OM). The results indicated that beta-phase transformations are highly dependent on cooling rate and on the presence of Ag. on slow cooling, the silver presence prevents the beta- and beta(1)-phase decomposition; thus, inducing the martensitic phase formation. After rapid cooling, a new thermal event is observed and the reverse martensitic transformation is shifted to lower temperatures.

Effects of the application of α1- and α2-adrenoceptor agonists and antagonists into the ventromedial hypothalamus on the sodium and potassium renal excretion

The effects of sodium and potassium excretion after intrahypothalamic administration of two α-adrenoceptor agonists and the effect of α-adrenoceptor antagonists were studied in groups of rats. Prazosin was equally effective at blocking the natriuretic and kaliuretic responses to the α1-adrenoceptor agonist phenylephrine and the mixed α1/α2-adrenoceptor agonist noradrenaline, while yohimbine which acts preferentially on α2-adrenoceptors was effective in potentiating these responses. These results suggest the presence of two types of α-adrenoceptors for the modulation of ventromedial hypothalamic pathways that interfere with the regulation of the two cations: stimulation of α1-adrenoceptors facilitates, while stimulation of α2-adrenoceptors inhibits the excretion of the ions.

Influence of the estrous cycle on the sensitivity to catecholamines in right atria from rats submitted to foot-shock stress

We investigated the mechanisms of the alterations in sensitivity to catecholamines in right atria from female rats exhibiting regular 4-day estrous cycles after three foot-shock sessions at estrus, metestrus, and diestrus or at diestrus, proestrus, and estrus. Right atria from stressed rats sacrificed at diestrus showed subsensitivity to noradrenaline and adrenaline. After in vitro sympathetic denervation (38 μM 6-hydroxydopamine) plus inhibition of neuronal reuptake (0.1 μM desipramine) subsensitivity to noradrenaline was abolished, but it was again evident when extraneuronal uptake was also inhibited (10 μM phenoxybenzamine and 30 μM corticosterone). The same pretreatment abolished the subsensitivity to adrenaline. After addition of 1 μM butoxamine, a β2-adrenoceptor antagonist, the tissues from stressed rats were subsensitive to adrenaline. Right atria from stressed rats sacrificed at estrus did not show any alteration in sensitivity to catecholamines. We conclude that after foot-shock stress, right atria from female rats sacrificed at diestrus showed subsensitivity of the chronotropic response to catecholamines as a result of a conformational alteration of β1-adrenoceptors, simultaneously with an increase in β2-adrenoceptor-mediated response. The mechanisms seem to be similar to those which underlie stress-induced alterations in catecholamine sensitivity in right atria from male rats. However, during estrus there are some protective factors that prevent the effects of stress on right atria.

Sulfonation and anticoagulant activity of fungal exocellular β-(1→6)-d-glucan (lasiodiplodan)

An exocellular β-(1→6)-d-glucan (lasiodiplodan) produced by a strain of Lasiodiplodia theobromae (MMLR) grown on sucrose was derivatized by sulfonation to promote anticoagulant activity. The structural features of the sulfonated β-(1→6)-d-glucan were investigated by UV-vis, FT-IR and 13C NMR spectroscopy, and the anticoagulant activity was investigated by the classical coagulation assays APTT, PT and TT using heparin as standard. The content of sulfur and degree of substitution of the sulfonated glucan was 11.73% and 0.95, respectively. UV spectroscopy showed a band at 261 nm due to the unsaturated bond formed in the sulfonation reaction. Results of FT-IR and 13C NMR indicated that sulfonyl groups were inserted on the polysaccharide. The sulfonated β-(1→6)-d-glucan presented anticoagulant activity as demonstrated by the increase in dose dependence of APTT and TT, and these actions most likely occurred because of the inserted sulfonate groups on the polysaccharide. The lasiodiplodan did not inhibit the coagulation tests. © 2012 Elsevier Ltd.

Noradrenergic neurotransmission within the bed nucleus of the stria terminalis modulates the retention of immobility in the rat forced swimming test

The bed nucleus of the stria terminalis (BNST) is a limbic structure that has a direct influence on the autonomic, neuroendocrine, and behavioral responses to stress. It was recently reported that reversible inactivation of synaptic transmission within this structure causes antidepressant-like effects, indicating that activation of the BNST during stressful situations would facilitate the development of behavioral changes related to the neurobiology of depression. Moreover, noradrenergic neurotransmission is abundant in the BNST and has an important role in the regulation of emotional processes related to the stress response. Thus, this study aimed to test the hypothesis that activation of adrenoceptors within the BNST facilitates the development of behavioral consequences of stress. To investigate this hypothesis, male Wistar rats were stressed (forced swimming, 15 min) and 24 h later received intra-BNST injections of vehicle, WB4101, RX821002, CGP20712, or ICI118,551, which are selective α1, α2, β1, and β2 adrenoceptor antagonists, respectively, 10 min before a 5-min forced swimming test. It was observed that administration of WB4101 (10 and 15 nmol), CGP20712 (5 and 10 nmol), or ICI118,551 (5 nmol) into the BNST reduced the immobility time of rats subjected to forced swimming test, indicating an antidepressant-like effect. These findings suggest that activation of α1, β1, and β2 adrenoceptors in the BNST could be involved in the development of the behavioral consequences of stress. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Expressão e caracterização farmacológica dos subtipos de adrenoceptores α1 na cauda proximal e distal do epidídimo de rato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Investigação da participação de adrenoceptores α1 no efeito antinociceptivo da amitriptilina em um modelo de dor neuropática

Tricyclic antidepressants, such as amitriptyline, are inhibitors of serotonin and norepinephrine neuronal reuptake and this action has been implied in changes in pain threshold supporting its use to alleviate neuropathic pain. Although is known that 1 adrenoceptors participate in the antinociceptive effect of amitriptyline it is unclear which receptor subtype is the target for the increased synaptic levels of norepinephrine resultant from the inhibition of neuronal uptake. Paradoxically, several tricyclic antidepressants including amitriptyline also behave as antagonists of 1 adrenoceptors with different affinities for its subtypes: these drugs have 10 to 100-fold higher affinities for 1A than for 1B and 1D adrenoceptors. This work investigated the involvement of 1 adrenoceptors subtypes in the antinociceptive effect of the amitriptyline in a constriction of the sciatic nerve in rats by determining the effects of subtype selective 1 adrenoceptors antagonists. Fifteen days later, mechanical hyperalgesia was analyzed in a Randall-Selitto test. The 1A-selective antagonist RS100329 was the most potent antagonist of the contractions of the rat prostate, whereas the 1D-selective antagonist BMY 7378 (up to 100g/Kg) was unable to affect these contractions. The antagonist prazosin, BMY 7378 and 5-methyl urapidil inhibited the antinociceptive effect of the amitriptyline. However, the highly selective 1A adrenoceptor antagonist RS100329 was unable to affect the antinociception induced by amitriptyline. These results point out that 1B and/or 1D adrenoceptors, but not 1A, are involved in the antinociceptive effects of amitriptyline

Investigação do envolvimento de subtipos de adrenoceptores α1 no efeito anti-imobilidade da imipramina no teste de suspensão pela cauda

Pós-graduação em Ciências Biológicas (Farmacologia) - IBB

Involvement of alpha(1B)-adrenoceptors in the anti-immobility effect of imipramine in the tail suspension test

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Alpha 1-adrenoceptor subtypes mediating the norepinephrine-induced contractile response in the rat vas deferens

The effects of chlorethylclonidine (CEC), 5-methyl-urapidil (5-MU), ryanodine and prolonged exposition to norepinephrine (NE) on the concentration-response curves (CRC) to this agonist on the bisected rat vas deferens (RVD) were investigated. 2. CEC did not affect the 50% effective concentration (EC50) of NE in either the prostatic (PP) or the epididymal (EP) portions of the RVD. 3. 5-MU did not alter the EC50 of NE in the PP but caused a significant and concentration-dependent rightward shift of the CRC to NE in the EP. 4. Ryanodine caused a shift to the right of the CRC to NE in the PP associated to a decrease in maximal response, but did not affect the CRC to NE in the EP. 5. Incubation of the EP with NE for 6 hr elicited a significant decrease in the maximal response with no changes in the EC50. Similar treatment of the PP was associated with a significant shift to the right of the CRC to NE without modifications in the maximal response. 6. These results suggest that in the RVD, NE interacts with two different alpha 1-adrenoceptors subtypes which are disposed in a selective manner along the RVD: the alpha 1(a) subtype in the EP, and non-alpha 1b-non-alpha 1a adrenoceptor subtype mainly located at the PP.

Mirabegron relaxes urethral smooth muscle by a dual mechanism involving β3-adrenoceptor activation and α1-adrenoceptor blockade

Mirabegron is the first β3-adrenoceptor (AR) agonist approved for treatment of overactive bladder syndrome (OAB). This study aimed to investigate the effects of β3-adrenoceptor (AR) agonist mirabegron in mouse urethra. The possibility that mirabegron exerts α1-AR antagonism was also tested in rat smooth muscle preparations presenting α1A- (vas deferens and prostate), α1D- (aorta) and α1B-AR (spleen). Functional assays were carried out in mouse and rat isolated tissues. Competition assays for the specific binding of [(3) H]Prazosin to membrane preparations of HEK 293 cells expressing each of the human α1-ARs, as well as β-AR mRNA expression and cyclic AMP measurements in mouse urethra were performed. Mirabegron produced concentration-dependent urethral relaxations that were right shifted by the selective β3-AR antagonist L 748,337, but unaffected by β1- and β2-AR antagonists (atenolol and ICI 118,551, respectively). Mirabegron-induced relaxations were enhanced by the phosphodiesterase-4 inhibitor rolipram, and this agonist stimulated cAMP synthesis. Mirabegron also produced rightward shifts in urethral contractions induced by the α1-AR agonist phenylephrine. Schild regression analysis revealed that mirabegron behaves as a competitive antagonist of α1-AR in urethra, vas deferens and prostate (α1A-AR, pA2  ≅ 5.6) and aorta (α1D-AR, pA2  ≅ 5.4), but not in spleen (α1B-AR). The affinities estimated for mirabegron in functional assays were consistent with those estimated in radioligand binding with human recombinant α1A- and α1D-ARs (pKi ≅ 6.0). The effects of mirabegron in urethral smooth muscle are the result of β3-AR agonism together with α1A / α1D-AR antagonism.

Transforming growth factor beta and apoptosis in leprosy skin lesions: possible relationship with the control of the tissue immune response in the Mycobacterium leprae infection

The course of leprosy depends of the host immune response which ranges from the lepromatous pole (LL) to the tuberculoid pole (TT). A comparative study was conducted in 60 patients with the LL and TT The results showed a mean expression of TGF-beta of 339 +/- 99.4 cells/field for TT and of 519.2 +/- 68.2 cells/field for LL. Frequency of apoptosis was 6.3 +/- 1.8 in TT and 14.0 +/- 6.1 in LL. A correlation (p = 0.0251) between TGF-beta and caspase-3 in the LL was found. This finding indicates a role of TGF-beta and apoptosis in the immune response in leprosy. (C) 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

MicroRNA miR-146b-5p regulates signal transduction of TGF-beta by repressing SMAD4 in thyroid cancer

MicroRNAs (miRNA) are small non-coding RNAs involved in post-transcriptional gene regulation that have crucial roles in several types of tumors, including papillary thyroid carcinoma (PTC). miR-146b-5p is overexpressed in PTCs and is regarded as a relevant diagnostic marker for this type of cancer. A computational search revealed that miR-146b-5p putatively binds to the 3' untranslated region (UTR) of SMAD4, an important member of the transforming growth factor beta (TGF-beta) signaling pathway. The TGF-beta pathway is a negative regulator of thyroid follicular cell growth, and the mechanism by which thyroid cancer cells evade its inhibitory signal remains unclear. We questioned whether the modulation of the TGF-beta pathway by miR-146b-5p can contribute to thyroid tumorigenesis. Luciferase reporter assay confirmed the direct binding of miR-146b-5p on the SMAD4 3'UTR. Specific inhibition of miR-146b-5p with a locked nucleic acid-modified anti-miR-146b oligonucleotide significantly increased SMAD4 levels in the human papillary carcinoma cell lines, TPC-1 and BCPAP. Moreover, suppression of miR-146b-5p increased the cellular response to the TGF-beta anti-proliferative signal, significantly decreasing the proliferation rate. The overexpression of miR-146b-5p in normal rat follicular PCCL3 cells decreased SMAD4 levels and disrupted TGF-beta signal transduction. MiR-146b-5p overexpression in PCCL3 cells also significantly increased cell proliferation in the absence of thyroid-stimulating hormone and conferred resistance to TGF-beta-mediated cell-cycle arrest. Additionally, the activation of thyroid most common oncogenes RET/PTC3 and BRAF in PCCL3 cells upregulated miR-146b-5p expression. Our results confirm the oncogenic role of miR-146b-5p in thyroid follicular cells and contribute to knowledge regarding the modulation of TGF-beta signal transduction by miRNAs in PTCs. Oncogene (2012) 31, 1910-1922; doi:10.1038/onc.2011.381; published online 29 August 2011

Präparation, Charakterisierung und elektronische Eigenschaften von dünnen Schichten des Hochtemperatursupraleiters HgReBa 2 Ca n-1 Cu n O y

Ziel dieser Arbeit war die Pr"{a}paration, Charakterisierung und Untersuchung der elektronischen Eigenschaften von d"{u}nnen Schichten des Hochtemperatursupraleiters HgReBa$_{2}$Ca$_{n-1}$Cu$_{n}$O$_{y}$, die mittels gepulster Laser-Deposition hergestellt wurden. Die HgRe1212-Filme zeigen in der AC-Suszeptibilit"{a}t einen scharfen "{U}bergang in die supraleitende Phase bei 124 K mit einer "{U}bergangsbreite von 2 K. Die resistiven "{U}berg"{a}nge der Proben wurden mit zunehmender St"{a}rke des externen Magnetfeldes breiter. Aus der Steigung der Arrheniusplots konnte die Aktivierungsenergie f"{u}r verschiedene Feldst"{a}rken bestimmt werden. Weiterhin wurde die Winkelabh"{a}ngigkeit des Depinning-Feldes $B_{dp}(theta)$ der Filme gemessen. Hieraus wurde ein Anisotropiewert von $gamma$ = 7.7 bei 105 K ermittelt. Dies ist relevant, um den f"{u}r Anwendungen wichtigen Bereich im $T$-$B$-$theta$-Phasenraum des Materials absch"{a}tzen zu k"{o}nnen. Die kritische Stromdichte $J_{c}$ der d"{u}nnen Filme aus HgRe-1212 wurde mit Hilfe eines SQUID-Magnetometers gemessen. Die entsprechenden $M$-$H$ Kurven bzw. das magnetische Moment dieser Filme wurde f"{u}r einen weiten Temperatur- und Feldbereich mit einem magnetischen Feld senkrecht zum Film aufgenommen. F"{u}r einen HgRe-1212-Film konnte bei 5 K eine kritische Stromdichte von 1.2 x 10$^{7}$ A/cm$^{2}$ und etwa 2 x 10$^{6}$ A/cm$^{2}$ bei 77 K ermittelt werden. Es wurde die Magnetfeld- und die Temperaturabh"{a}ngigkeit des Hall-Effekts im normalleitenden und im Mischzustand in Magnetfeldern senkrecht zur $ab$-Ebene bis zu 12 T gemessen. Oberhalb der kritischen Temperatur $T_{c}$ steigt der longitudinale spezifische Widerstand $rho_{xx}$ linear mit der Temperatur, w"{a}hrend der spezifische Hall-Widerstand $rho_{yx}$ sich umgekehrt proportional zur Temperatur "{a}ndert. In der N"{a}he von $T_{c}$ und in Feldern kleiner als 3 T wurde eine doppelte Vorzeichen"{a}nderung des spezifischen Hall-Widerstandes beobachtet. Der Hall-Winkel im Normalzustand, cot $theta_{H}= alpha T^{2} + beta$, folgt einer universellen $textit{T }^{2}$-Abh"{a}ngigkeit in allen magnetischen Feldern. In der N"{a}he des Nullwiderstand-Zustandes h"{a}ngt der spezifische Hall-Widerstand $rho_{yx}$ "{u}ber ein Potenzgesetz mit dem longitudinalen Widerstand $rho_{xx}$ zusammen. Das Skalenverhalten zwischen $rho_{yx}$ und $rho_{xx}$ weist eine starke Feld-Abh"{a}ngigkeit auf. Der Skalenexponent $beta$ in der Gleichung $rho_{yx}$ =A $rho_{xx}^{beta}$ steigt von 1.0 bis 1.7, w"{a}hrend das Feld von 1.0 bis 12 T zunimmt.

Studio di espressione e funzione della PLCβ1 nucleare in modelli murini ed umani di cellule ematopoietiche mieloidi e linfoidi

The aims of this work were to investigate the role of nuclear Phospholipase C beta 1 (PI-PLCβ1) in human and mouse cell lines and to identify new binding partners of nuclear PI-PLCβ1 to further understand the functional network in which the enzyme acts. The intracellular distribution of PI-PLCβ1 was further investigated in human leukaemia cell lines (NB4, HL60, THP1, CEM, Jurkat, K562). With the exception of HL60, a high endogenous level of PI-PLCβ1 was detected in purified nuclei in each of the cell lines. We found that also in Ba/F3 pro-B cells overexpressing PI-PLCβ1b the protein localize within the nucleus. Although our data demonstrated that PI-PLCβ1b was not involved in cell proliferation and IGF-1 response as shown in other cell lines (FELC and Swiss 3T3), there was an effect on apoptosis. Activation of early apoptotic markers caspase-3 and PARP was delayed in PI-PLCβ1b overexpressing Ba/F3 cells treated with 5 gr/ml mitomycin C for 24h. We performed an antibody-specific immunoprecipitation on nuclear lysates from FELC-PLCβ1b cells. Mass spectrometry analysis (nano-ESI-Q-TOF) of co-immunoprecipitated proteins allowed for identification of 92 potential nuclear PI-PLCβ1b interactors. Among these, several already documented PI-PLCβ1b interacting partners (Srp20, LaminB, EF1α2) were identified, further validating our data. All the identified proteins were nuclear, mostly localized within the nuclear speckles. This evidence is particularly relevant as PI-PLCβ1 is known to localize in the same domains. Many of the identified proteins are involved in cell cycle, proliferation and transcriptional control. In particular, many of the proteins are components of the spliceosome multi-complex, strengthening the idea that PI-PLCβ1b is involved in mRNA processing and maturation. Future work will aim to better characterize the regulatory role of PI-PLCβ1b in mRNA splicing.