Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 73
Filtrar
1.
Ann Oncol ; 33(8): 814-823, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35513244

RESUMO

BACKGROUND: Difference in pathologic complete response (pCR) rate after neoadjuvant chemotherapy does not capture the impact of treatment on downstaging of residual cancer in the experimental arm. We developed a method to compare the entire distribution of residual cancer burden (RCB) values between clinical trial arms to better quantify the differences in cytotoxic efficacy of treatments. PATIENTS AND METHODS: The Treatment Efficacy Score (TES) reflects the area between the weighted cumulative distribution functions of RCB values from two trial arms. TES is based on a modified Kolmogorov-Smirnov test with added weight function to capture the importance of high RCB values and uses the area under the difference between two distribution functions as a statistical metric. The higher the TES the greater the shift to lower RCB values in the experimental arm. We developed TES from the durvalumab + olaparib arm (n = 72) and corresponding controls (n = 282) of the I-SPY2 trial. The 11 other experimental arms and control cohorts (n = 947) were used as validation sets to assess the performance of TES. We compared TES to Kolmogorov-Smirnov, Mann-Whitney, and Fisher's exact tests to identify trial arms with higher cytotoxic efficacy and assessed associations with trial arm level survival differences. Significance was assessed with a permutation test. RESULTS: In the validation set, TES identified arms with a higher pCR rate but was more accurate to identify regimens as less effective if treatment did not reduce the frequency of high RCB values, even if the pCR rate improved. The correlation between TES and survival was higher than the correlation between the pCR rate difference and survival. CONCLUSIONS: TES quantifies the difference between the entire distribution of pathologic responses observed in trial arms and could serve as a better early surrogate to predict trial arm level survival differences than pCR rate difference alone.


Assuntos
Antineoplásicos , Neoplasias da Mama , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/patologia , Feminino , Humanos , Terapia Neoadjuvante , Neoplasia Residual/tratamento farmacológico , Neoplasia Residual/patologia , Resultado do Tratamento
2.
Nat Mater ; 20(12): 1615-1628, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33972762

RESUMO

Isolating single molecules in the solid state has allowed fundamental experiments in basic and applied sciences. When cooled down to liquid helium temperature, certain molecules show transition lines that are tens of megahertz wide, limited by only the excited-state lifetime. The extreme flexibility in the synthesis of organic materials provides, at low costs, a wide palette of emission wavelengths and supporting matrices for such single chromophores. In the past few decades, their controlled coupling to photonic structures has led to an optimized interaction efficiency with light. Molecules can hence be operated as single-photon sources and as nonlinear elements with competitive performance in terms of coherence, scalability and compatibility with diverse integrated platforms. Moreover, they can be used as transducers for the optical read-out of fields and material properties, with the promise of single-quanta resolution in the sensing of charges and motion. We show that quantum emitters based on single molecules hold promise to play a key role in the development of quantum science and technologies.


Assuntos
Óptica e Fotônica , Fótons , Temperatura
3.
Community Dent Health ; 37(4): 242-246, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32306563

RESUMO

BACKGROUND: Temporomandibular joint disorders (TMD) affect up to 50% of the population. Chronic TMD may have a significant impact on patients' quality of life and is associated with a significant cost burden to health services. AIMS: The aim of this study was to investigate the incidence of TMD in Greater Manchester and to determine the most appropriate setting for its management. METHODS: Data were retrospectively collected on the demographics, symptoms and management provided to patients referred for TMD. RESULTS: There were 789 referrals analysed; 616 to a Tertiary Centre and 173 to a District General Hospital (DGH). The most common reason for referral was pain (82%), followed by limitation in opening (55%) and clicks or sounds (44%). 27% of referrals were managed with a splint and 12% were provided with advice or a patient information leaflet prior to referral. DISCUSSION: The effect of chronic pain on patients' quality of life and the cost burden of its management compels us to review current practices in referral and management of TMD. Barriers to provision of treatment in primary care may include a lack of training, remuneration or confidence. These may be overcome with the development of self-care plans for patients and a care pathway for practitioners. CONCLUSION: Based on existing evidence, timely and conservative management of TMD should be encouraged in primary care, enabling better outcomes to be achieved for patients and the maintenance of the experience and skill level of specialist services in secondary care.


Assuntos
Dor Crônica , Transtornos da Articulação Temporomandibular , Humanos , Qualidade de Vida , Encaminhamento e Consulta , Estudos Retrospectivos , Transtornos da Articulação Temporomandibular/terapia
5.
Ann Oncol ; 27(4): 555-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26802154
6.
Opt Lett ; 40(11): 2489-92, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26030539

RESUMO

Heralded single photons produced on a silicon chip represent an integrated photon source solution for scalable photonic quantum technologies. The key limitation of such sources is their non-deterministic nature introduced by the stochastic spontaneous four-wave mixing (SFWM) process. Active spatial and temporal multiplexing can improve this by enhancing the single-photon rate without degrading the quantum signal-to-noise ratio. Here, taking advantage of the broad bandwidth of SFWM in a silicon nanowire, we experimentally demonstrate heralded single-photon generation from a silicon nanowire pumped by time and wavelength division multiplexed pulses. We show a 90±5% enhancement on the heralded photon rate at the cost of only 14±2% reduction to the signal-to-noise ratio, close to the performance found using only time division multiplexed pulses. As single-photon events are distributed to multiple wavelength channels, this new scheme overcomes the saturation limit of avalanche single-photon detectors and will improve the ultimate performance of such photon sources.

7.
Opt Lett ; 38(23): 5176-9, 2013 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-24281539

RESUMO

We demonstrate integrated spatial multiplexing of heralded single photons generated from a single 96 µm long silicon photonic crystal waveguide in a bidirectional pump configuration. By using a low-loss fiber-coupled opto-ceramic switch, the multiplexing technique enhances the brightness of the single photon source by 51.2±4.0% while maintaining the coincidence-to-accidental ratio. Compared with the demonstration of multiplexing two individual sources, the bidirectional pump scheme represents a twofold reduction in the footprint of nonlinear devices for future large-scale integration of on-chip single photon sources. The 51.2±4.0% gain will make any quantum operation requiring n photons 1.5(n) times faster.

8.
Nat Commun ; 4: 2582, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24107840

RESUMO

The non-deterministic nature of photon sources is a key limitation for single-photon quantum processors. Spatial multiplexing overcomes this by enhancing the heralded single-photon yield without enhancing the output noise. Here the intrinsic statistical limit of an individual source is surpassed by spatially multiplexing two monolithic silicon-based correlated photon pair sources in the telecommunications band, demonstrating a 62.4% increase in the heralded single-photon output without an increase in unwanted multipair generation. We further demonstrate the scalability of this scheme by multiplexing photons generated in two waveguides pumped via an integrated coupler with a 63.1% increase in the heralded photon rate. This demonstration paves the way for a scalable architecture for multiplexing many photon sources in a compact integrated platform and achieving efficient two-photon interference, required at the core of optical quantum computing and quantum communication protocols.

9.
Sci Rep ; 3: 2032, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23783585

RESUMO

Quantum networks involve entanglement sharing between multiple users. Ideally, any two users would be able to connect regardless of the type of photon source they employ, provided they fulfill the requirements for two-photon interference. From a theoretical perspective, photons coming from different origins can interfere with a perfect visibility, provided they are made indistinguishable in all degrees of freedom. Previous experimental demonstrations of such a scenario have been limited to photon wavelengths below 900 nm, unsuitable for long distance communication, and suffered from low interference visibility. We report two-photon interference using two disparate heralded single photon sources, which involve different nonlinear effects, operating in the telecom wavelength range. The measured visibility of the two-photon interference is 80 ± 4%, which paves the way to hybrid universal quantum networks.

10.
Neuroscience ; 226: 397-410, 2012 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-22989919

RESUMO

Anabolic androgenic steroids (AAS), synthetic testosterone derivatives that are used for ergogenic purposes, alter neurotransmission and behaviors mediated by GABA(A) receptors. Some of these effects may reflect direct and rapid action of these synthetic steroids at the receptor. The ability of other natural allosteric steroid modulators to alter GABA(A) receptor-mediated currents is dependent upon the phosphorylation state of the receptor complex. Here we show that phosphorylation of the GABA(A) receptor complex immunoprecipitated by ß(2)/ß(3) subunit-specific antibodies from the medial preoptic area (mPOA) of the mouse varies across the estrous cycle; with levels being significantly lower in estrus. Acute exposure to the AAS, 17α-methyltestosterone (17α-MeT), had no effect on the amplitude or kinetics of inhibitory postsynaptic currents in the mPOA of estrous mice when phosphorylation was low, but increased the amplitude of these currents from mice in diestrus, when it was high. Inclusion of the protein kinase C (PKC) inhibitor, calphostin, in the recording pipette eliminated the ability of 17α-MeT to enhance currents from diestrous animals, suggesting that PKC-receptor phosphorylation is critical for the allosteric modulation elicited by AAS during this phase. In addition, a single injection of 17α-MeT was found to impair an mPOA-mediated behavior (nest building) in diestrus, but not in estrus. PKC is known to target specific serine residues in the ß(3) subunit of the GABA(A) receptor. Although phosphorylation of these ß(3) serine residues showed a similar profile across the cycle, as did phosphoserine in mPOA lysates immunoprecipitated with ß2/ß3 antibody (lower in estrus than in diestrus or proestrus), the differences were not significant. These data suggest that the phosphorylation state of the receptor complex regulates both the ability of AAS to modulate receptor function in the mPOA and the expression of a simple mPOA-dependent behavior through a PKC-dependent mechanism that involves the ß(3) subunit and other sites within the GABA(A) receptor complex.


Assuntos
Anabolizantes/farmacologia , Androgênios/farmacologia , Ciclo Estral/fisiologia , Metiltestosterona/farmacologia , Área Pré-Óptica/efeitos dos fármacos , Receptores de GABA-A/metabolismo , Androstano-3,17-diol/farmacologia , Animais , Ansiedade/psicologia , Comportamento Animal/efeitos dos fármacos , Western Blotting , Feminino , Imunoprecipitação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/isolamento & purificação , Proteínas do Tecido Nervoso/metabolismo , Comportamento de Nidação/efeitos dos fármacos , Fosforilação , Fosfosserina/metabolismo , Área Pré-Óptica/metabolismo , Proteína Quinase C/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Maturidade Sexual
11.
Anal Chim Acta ; 673(1): 26-32, 2010 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-20630174

RESUMO

Raman spectroscopy has significant potential for the quantification of food products. Milk powder is an important foodstuff and ingredient that is produced on large scale (over 20 million tonnes per annum). Raman spectroscopy, unlike near- and mid-infrared spectroscopies, has not been used extensively to quantify milk powder constituents. The effect of sample presentation on spectroscopic calibrations of protein and fat for 136 New Zealand milk powders was assessed using Raman spectroscopy. Prediction models were produced to quantify a protein concentration range of 32.19-37.65% w/w for skim milk powder, and a protein concentration range of 23.34-25.02% w/w and a fat concentration range of 26.26-29.68% w/w for whole milk powder (where ratios of prediction to deviation exceeded 2.6 with one exception). The resultant calibrations were not influenced by sample orientation; the sample temperature during data collection did affect the calibrations. Calcium fortification in the form of calcium carbonate was identified within a sub-set of samples, reinforcing the efficacy of Raman spectroscopy for identifying both crystalline and non-crystalline constituents within milk powder.


Assuntos
Leite/química , Análise Espectral Raman/métodos , Animais , Cálcio/análise , Calibragem , Gorduras/análise , Alimentos Fortificados/análise , Nova Zelândia , Pós/química , Proteínas/análise
12.
Anal Methods ; 1(1): 29-38, 2009 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-32938139

RESUMO

The functionality of anhydrous milk fat (AMF) is determined from solid fat content (SFC) and triacylglycerol (TG) profiles, parameters traditionally measured using nuclear magnetic resonance and high pressure liquid chromatography respectively. Raman spectroscopy coupled with partial least squares (PLS) analysis has been assessed as an alternative method for SFC and TG class quantification. Sample temperature at which the Raman spectra were collected, method of spectral preprocessing and type of PLS analysis were all investigated and found to significantly affect the resulting calibrations (as parameterized by root mean square error of cross validation). Physically heterogeneous AMF samples held at 20 °C were shown to allow reliable SFC predictions on the basis of collected Raman spectra. In contrast to SFC calibrations, physically homogenous samples in a liquid form were ideal for TG class concentration predictions, however, not all TG classes could be reliably predicted.

13.
Neuroscience ; 138(3): 793-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16310317

RESUMO

Anabolic androgenic steroids are synthetic derivatives of testosterone designed for therapeutic purposes, but now taken predominantly as drugs of abuse. The most common behavioral effects associated with anabolic androgenic steroid use are changes in anxiety, aggression and reproductive behaviors, including the onset of puberty and sexual receptivity. GABAergic circuits in the forebrain underlie these behaviors and are regulated by gonadal steroids. Work from our laboratories has shown that the expression and function of GABA(A) receptors in the rat and mouse forebrain varies between the sexes and across the estrous cycle. We have also shown that there are significant changes in GABA(A) receptor expression that occur with the progression through puberty to adulthood. Because GABAergic systems are both steroid-sensitive and critical for the expression of behaviors altered with anabolic androgenic steroid use, forebrain GABA(A) receptors are an attractive candidate to assess how molecular actions of anabolic androgenic steroids may be translated to known behavioral outcomes. Our studies demonstrate that anabolic androgenic steroids elicit both acute modulation of GABA(A) receptor-mediated currents, as well as chronic regulation of GABA(A) receptor expression and forebrain GABAergic transmission. Because anabolic androgenic steroid use has now become prevalent not only among adolescent boys, but in an increasing number of adolescent girls, we have also been particularly interested in determining age- and sex-specific effects of anabolic androgenic steroids. Our data show that the effects of chronic anabolic androgenic steroid exposure can be greater for adolescent than adult animals and are more marked in females than in males. These data have particularly important implications with respect to studies we have done demonstrating that chronic anabolic androgenic steroid exposure alters the onset of puberty, estrous cyclicity and sexual receptivity.


Assuntos
Anabolizantes/farmacologia , Androgênios/farmacologia , Prosencéfalo/fisiologia , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/fisiologia , Adolescente , Animais , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Prosencéfalo/efeitos dos fármacos , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/genética , Transmissão Sináptica/efeitos dos fármacos
14.
Cancer Res ; 61(12): 4892-900, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11406568

RESUMO

We investigated whether combined treatment with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and trastuzumab could enhance the specific killing of cells that overexpress the erbB-2 receptor. The combination resulted in an enhancement of TRAIL-mediated apoptosis in all cell lines overexpressing erbB-2 receptor compared with either reagent alone. In contrast, there was no effect in cell lines with low levels of the erb-B2 receptor. Trastuzumab treatment resulted in down-regulation of the erbB-2 receptor in all erbB-2-overexpressing cell lines. Similar enhancement of TRAIL toxicity was observed when the erbB-2 receptor was down-regulated using antisense oligodeoxynucleotides. Down-regulation of the erbB-2 receptor protein by trastuzumab or antisense oligodeoxynucleotides decreased Akt kinase activation but not mitogen-activated protein kinase activation. Down-regulation of Akt kinase activity by a phosphatidylinositol 3'-kinase inhibitor (LY294002) also resulted in enhancement of TRAIL-mediated apoptosis. Expression of a constitutively active form of Akt kinase in an erbB-2-overexpressing cell line completely abrogated the increase in TRAIL-mediated apoptosis by trastuzumab and significantly reduced the biological effect of either reagent alone. Therefore, down-regulation of the erbB-2 receptor by trastuzumab enhances TRAIL-mediated apoptosis by inhibiting Akt kinase activity. These data suggest that the combination of trastuzumab and TRAIL may allow enhanced therapeutic efficacy and specificity in the treatment of erbB-2-overexpressing tumors.


Assuntos
Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Glicoproteínas de Membrana/farmacologia , Neoplasias Ovarianas/patologia , Proteínas Serina-Treonina Quinases , Receptor ErbB-2/biossíntese , Fator de Necrose Tumoral alfa/farmacologia , Anticorpos Monoclonais Humanizados , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Regulação para Baixo/efeitos dos fármacos , Sinergismo Farmacológico , Feminino , Humanos , Glicoproteínas de Membrana/genética , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Receptor ErbB-2/genética , Receptor ErbB-2/fisiologia , Proteínas Recombinantes de Fusão/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF , Trastuzumab , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/genética
15.
Cancer Res ; 61(10): 3986-97, 2001 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-11358816

RESUMO

To evaluate the role of Akt/PKB in non-small cell lung cancer (NSCLC) survival, we analyzed NSCLC cell lines that differed in tumor histology as well as p53, Rb, and K-ras status. Constitutive Akt/protein kinase B (PKB) activity was demonstrated in 16 of 17 cell lines by maintenance of S473 phosphorylation with serum deprivation. Additional analysis of five of 2these NSCLC lines revealed that phosphorylation of S473 and T308 correlated with in vitro kinase activity. Akt/PKB activation was phosphatidylinositol 3-kinase-dependent and promoted survival because the phosphatidylinositol 3 inhibitors LY294002 and wortmannin inhibited Akt/PKB phosphorylation, Akt/PKB activity, and increased apoptosis only in cells with active Akt/PKB. To test whether Akt/PKB activity promoted therapeutic resistance, LY294002 was added with individual chemotherapeutic agents or irradiation. LY294002 greatly potentiated chemotherapy-induced apoptosis in cells with high Akt/PKB levels, but did not significantly increase chemotherapy-induced apoptosis in cells with low Akt/PKB levels. Combined with radiation in cells with active Akt/PKB, LY294002 additively increased apoptosis and inhibited clonogenic growth. These results were extended with transiently transfected Akt/PKB mutants. Transfecting dominant negative Akt/PKB decreased Akt/PKB activity and increased basal apoptosis as well as chemotherapy- and irradiation-induced apoptosis only in cells with high Akt/PKB activity. Conversely, transfecting constitutively active Akt/PKB into cells with low Akt/PKB activity increased Akt/PKB activity and attenuated chemotherapy- and radiation-induced apoptosis. We therefore identify Akt/PKB as a constitutively active kinase that promotes survival of NSCLC cells and demonstrate that modulation of Akt/PKB activity by pharmacological or genetic approaches alters the cellular responsiveness to therapeutic modalities typically used to treat patients with NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/enzimologia , Neoplasias Pulmonares/enzimologia , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Sobrevivência Celular/fisiologia , Cromonas/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/radioterapia , Morfolinas/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-akt , Tolerância a Radiação/efeitos dos fármacos , Tolerância a Radiação/fisiologia , Transfecção , Células Tumorais Cultivadas
16.
Biol Reprod ; 64(5): 1460-5, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11319152

RESUMO

The effects of anabolic-androgenic steroid (AAS) abuse on the onset of puberty in female adolescents are largely unknown. This study assessed the acute effects of one AAS, stanozolol, on pubertal onset in the female rat. A single injection of stanozolol (5 mg/kg) on Postnatal Day (PN) 21 advanced vaginal opening but did not alter the onset of vaginal estrus. Higher doses of stanozolol treatment (10 and 25 mg/kg) also advanced vaginal opening but had no effect on vaginal estrus. The advancement of vaginal opening by stanozolol (5 mg/kg) was prevented by the concomitant administration of the pure antiestrogen ICI 182,780 (1 mg/kg) on PN20-22. Administration of the androgen receptor antagonist flutamide (10 mg/kg twice daily) on PN20-22 had no effect on the advancement of vaginal opening by stanozolol. Stanozolol treatment also advanced vaginal opening in ovariectomized rats. Perivaginal injections of a low dose of stanozolol (0.05 mg) on PN21 and PN23 also advanced vaginal opening. These results suggest that stanozolol is acting directly at estrogen receptors in the vaginal epithelium to advance vaginal opening and that prepubertal stanozolol treatment does not induce true precocious puberty.


Assuntos
Anabolizantes/farmacologia , Maturidade Sexual/efeitos dos fármacos , Estanozolol/farmacologia , Anabolizantes/administração & dosagem , Antagonistas de Androgênios/farmacologia , Animais , Relação Dose-Resposta a Droga , Estradiol/análogos & derivados , Estradiol/farmacologia , Antagonistas de Estrogênios/farmacologia , Estro/efeitos dos fármacos , Feminino , Flutamida/farmacologia , Fulvestranto , Ratos , Ratos Long-Evans , Estanozolol/administração & dosagem , Vagina/efeitos dos fármacos , Vagina/crescimento & desenvolvimento
17.
Horm Behav ; 39(2): 121-30, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11243740

RESUMO

The present study investigates the effects of the antiestrogen ICI 182,780 (ICI) on the display of sexual behaviors in female rats. ICI 182,780 is a pure anti-estrogen and when given systemically, ICI is thought to act only in the periphery, and is not believed to cross the blood brain barrier. The present study examines the effects of ICI on sexual receptivity and on paced mating behavior following treatment with estradiol benzoate (EB) and progesterone (P) (Experiment 1) or with EB alone (Experiment 2). In Experiment 1, ICI (250.0 microg) did not affect the display of receptivity or paced mating behavior induced by EB and P. In contrast, in Experiment 2 female rats receiving EB alone displayed a decrease in the level of sexual receptivity following treatment with 500.0 and 750.0 microg ICI (but not 250.0 microg ICI). In addition, in Experiment 2 EB-treated female rats receiving 250.0 microg ICI spent more time away from the male rat following an intromission and were more likely to exit from the male compartment following a mount. Last, ICI had potent antiestrogenic effects on vaginal cytology (Experiment 2) and on the uterus (Experiments 1 and 2). The present study supports a role for peripheral estrogen receptors in sexual receptivity and paced mating behavior and suggests that estrogen receptor activation may decrease the aversive sensation associated with sexual stimulation.


Assuntos
Estradiol/análogos & derivados , Estradiol/farmacologia , Antagonistas de Estrogênios/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Animais , Estradiol/administração & dosagem , Antagonistas de Estrogênios/administração & dosagem , Feminino , Fulvestranto , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ovariectomia , Progesterona/farmacologia , Ratos , Ratos Long-Evans , Útero/efeitos dos fármacos , Vagina/citologia , Vagina/efeitos dos fármacos
18.
Physiol Behav ; 70(1-2): 205-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10978497

RESUMO

During a sexual encounter with a male rat, a female rat will display both receptive (lordosis) and proceptive (hopping, darting, and ear-wiggling) behaviors. Additionally, if mating occurs in an environment where the female rat may approach and withdraw from the male rat, she will control the timing of the receipt of mounts, intromissions, and ejaculations. This temporal patterning by the female rat is known as paced mating behavior. The present experiment compared paced mating behavior in rats during an intact, proestrous phase and an ovariectomized phase, during which they were treated with estradiol benzoate (10 microg per rat) and progesterone (0.5 mg per rat). Though no differences in sexual receptivity were observed across the two phases, patterns of paced mating behavior were found to differ. Specifically, female rats exhibited significantly longer contact-return latencies when hormone treated than when intact.


Assuntos
Estrogênios/farmacologia , Estro/fisiologia , Comportamento Sexual Animal/fisiologia , Animais , Estradiol/farmacologia , Feminino , Masculino , Ovariectomia , Postura/fisiologia , Progesterona/farmacologia , Ratos , Ratos Long-Evans
19.
Horm Behav ; 35(2): 144-54, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10202122

RESUMO

A female rat will display a repertoire of behaviors during a sexual encounter with a male rat including sexually receptive (the lordosis response) and proceptive (hopping, darting) behaviors. In addition, when given the opportunity, a sexually receptive female rat will approach and withdraw from the male rat, controlling the timing of the receipt of mounts, intromissions, and ejaculations, a behavior known as paced mating behavior. The present experiments tested the hypotheses (1) that progesterone regulates paced mating behavior, and (2) that multiple hormone regimens used previously to induce sexual receptivity have the same effect on paced mating behavior. Paced mating behavior was assessed in sexually receptive ovariectomized female rats after treatment with: (1) estradiol benzoate (EB; 30.0 mg/kg) followed by a range of doses of progesterone (P; 1.0-8.0 mg/kg), (2) two pulses of unesterified estradiol (E2; 2.0 microg/rat) followed by 1.0 mg/rat of P, and (3) EB alone (5.0 microg/rat) for 6 days. No differences in sexual receptivity or in paced mating behavior were observed across doses of P (1.0-8.0 mg/kg). In contrast, the number of hops and darts per min increased with the dose of P administered. E2 + P administration resulted in slightly, but significantly, lower levels of sexual receptivity along with significantly longer contact-return latencies following an intromission in relation to the other treatment conditions. In addition, female rats exhibited fewer hops and darts per min in response to E2 + P than in response to EB + 8.0 mg/kg of P. The administration of EB alone for 6 days induced levels of receptivity and paced mating behavior indistinguishable from EB + P, while eliciting significantly fewer hops and darts per min than the EB + 8.0 mg/kg P treatment condition. Hormone priming regimen had no effect on the percentage of exits displayed during the paced mating tests in any experimental phase. Dose of P had no effect on paced mating behavior in sexually receptive rats. In addition, P does not appear to be necessary for the display of paced mating behavior following long-term treatment with EB. In contrast, the pulsatile administration of E2 + P induced a different pattern of paced mating behavior in sexually receptive rats.


Assuntos
Copulação/efeitos dos fármacos , Estradiol/análogos & derivados , Progesterona/farmacologia , Ratos Long-Evans/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Estradiol/farmacologia , Feminino , Masculino , Ovariectomia , Fluxo Pulsátil , Ratos , Tempo de Reação/efeitos dos fármacos
20.
J Neurophysiol ; 81(1): 192-203, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9914280

RESUMO

Gamma-aminobutyric acid type A (GABAA) receptors expressed within the medial preoptic area (mPOA) are known to play a critical role in regulating sexual and neuroendocrine functions. In the rat brain, high levels of expression of the gamma1 subunit mRNA of the GABAA receptor are restricted to a limited number of regions that mediate sexual behaviors, including the mPOA. The biophysical and pharmacological profiles of native gamma1-containing receptors in neurons are unknown. Here, we have characterized the properties of GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) and currents elicited by fast perfusion of GABA to isolated mPOA neurons of juvenile male and female rats. No significant sex-specific differences were evident in the mean peak amplitude, distribution of event amplitudes, kinetics of current decay, or the frequency of sIPSCs. The profile of modulation of sIPSCs by diazepam, beta-CCM and zolpidem, allosteric modulators that act at the benzodiazepine (BZ) site of the GABAA receptor, support the assertion that mPOA neurons of both sexes express functional gamma1-containing receptors. The ability of zolpidem to modulate both sIPSC amplitude and currents elicited by rapid perfusion of GABA to mPOA neurons differed significantly between the sexes. Zolpidem reversibly induced negative modulation of currents in mPOA neurons isolated from male rats, but had no effect in mPOA neurons from female rats. Concentration-response analysis of responses in neurons acutely isolated from male rats indicated an IC50 of 58 nM with maximal decreases of approximately 50% of control peak current amplitude. In situ hybridization analysis demonstrated that levels of the gamma1 subunit mRNA are significantly higher in mPOA neurons from male than female rats. No significant sex-specific differences were detected in the levels of alpha1, alpha2, or alpha5 mRNAs. These results suggest that native gamma1-containing receptors are expressed in primary neurons of the mPOA and that sex-specific differences in the expression of this subunit may contribute to sexual dimorphism in GABAA receptor modulation by compounds acting at the BZ site.


Assuntos
Neurônios/metabolismo , Área Pré-Óptica/metabolismo , RNA Mensageiro/biossíntese , Receptores de GABA-A/biossíntese , Animais , Estimulação Elétrica , Eletrofisiologia , Feminino , Hipnóticos e Sedativos/farmacologia , Hibridização In Situ , Masculino , Potenciais da Membrana/fisiologia , Neurônios/efeitos dos fármacos , Técnicas de Patch-Clamp , Área Pré-Óptica/citologia , Área Pré-Óptica/efeitos dos fármacos , Piridinas/farmacologia , Ratos , Caracteres Sexuais , Zolpidem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...