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1.
Pharmacogenomics J ; 21(4): 423-434, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33070160

RESUMO

Implementation of pharmacogenetics (PGx) and individualization of drug therapy is supposed to obviate adverse drug reactions or therapy failure. Health care professionals (HCPs) use drug labels (DLs) as reliable information about drugs. We analyzed the Swiss DLs to give an overview on the currently available PGx instructions. We screened 4306 DLs applying natural language processing focusing on drug metabolism (pharmacokinetics) and we assigned PGx levels following the classification system of PharmGKB. From 5979 hits, 2564 were classified as PGx-relevant affecting 167 substances. 55% (n = 93) were classified as "actionable PGx". Frequently, PGx information appeared in the pharmacokinetics section and in DLs of the anatomic group "nervous system". Unstandardized wording, appearance of PGx information in different sections and unclear instructions challenge HCPs to identify and interpret PGx information and translate it into practice. HCPs need harmonization and standardization of PGx information in DLs to personalize drug therapies and tailor pharmaceutical care.


Assuntos
Rotulagem de Medicamentos/métodos , Preparações Farmacêuticas/química , Farmacogenética/métodos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Humanos , Testes Farmacogenômicos/métodos , Suíça
2.
Nuklearmedizin ; 49(1): 1-5, 2010.
Artigo em Alemão | MEDLINE | ID: mdl-20087535

RESUMO

The call by the Institute for Quality and Efficiency in Health Care (IQWiG) for randomised controlled trials (RCTs) to prove the patient-relevant benefit of positron emission tomography (PET) is currently a controversial topic in Germany. From a methodological point of view there is essentially no difference between diagnostic procedures and therapeutic (drug or non-drug) interventions in proving their causal benefit. A broad consensus has been reached since the 1960s (e.g. FDA regulations) that RCTs are the methodological gold standard for therapeutic interventions. Nevertheless, the same arguments that were cited against RCTs in assessing the benefit of therapeutic interventions are now used against RCTs in evaluating diagnostic tests (e.g. ethical problems, feasibility, etc.). This paper summarizes the central methodological arguments of the discussion on the benefit assessment of PET in malignant lymphomas from the perspective of IQWiG and its external experts.


Assuntos
Linfoma/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/normas , Medição de Risco , Medicina Baseada em Evidências/normas , Alemanha , Humanos , Tomografia por Emissão de Pósitrons/efeitos adversos , Tomografia por Emissão de Pósitrons/métodos , Garantia da Qualidade dos Cuidados de Saúde , Radiografia , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
J Comput Neurosci ; 26(1): 39-53, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18461432

RESUMO

The impact of structure in modulating synaptic signals originating in dendrites is widely recognized. In this study, we focused on the impact of dendrite morphology on a local spike generating mechanism which has been implicated in hormone secretion, the after depolarization potential (ADP). Using multi-compartmental models of hypothalamic GnRH neurons, we systematically truncated dendrite length and determined the consequence on ADP amplitude and repetitive firing. Decreasing the length of the dendrite significantly increased the amplitude of the ADP and increased repetitive firing. These effects were observed in dendrites both with and without active conductances suggesting they largely reflect passive characteristics of the dendrite. In order to test the findings of the model, we performed whole-cell recordings in GnRH neurons and elicited ADPs using current injection. During recordings, neurons were filled with biocytin so that we could determine dendritic and total projection (dendrite plus axon) length. Neurons exhibited ADPs and increasing ADP amplitude was associated with decreasing dendrite length, in keeping with the predictions of the models. Thus, despite the relatively simple morphology of the GnRH neuron's dendrite, it can still exert a substantial impact on the final neuronal output.


Assuntos
Potenciais de Ação , Dendritos/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/fisiologia , Potenciais da Membrana , Neurônios/fisiologia , Animais , Simulação por Computador , Estimulação Elétrica , Feminino , Hipotálamo/citologia , Lisina/análogos & derivados , Camundongos , Modelos Neurológicos , Neurônios/citologia , Técnicas de Patch-Clamp , Fotomicrografia
4.
Heliyon ; 5(10): e02635, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31687498

RESUMO

Agro-wastes such as sugar cane bagasse can be explored for use in different aspects. Its applicability as a source of cellulose has attracted much interests especially in biomedical field among various applications. In the current work chemically purified cellulose (CPC) and cellulose nanocrystals (CNCs) were effectively extracted from sugarcane bagasse (SCB). The cellulose was obtained by chemical treatment of SCB using HNO3, NaOH and a bleaching agent. Nanocrystals were further prepared from the extracted cellulose using H2SO4 hydrolysis followed by washing with deionized water and acetone. The obtained materials were characterized for surface morphological using Fourier transform infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD) analysis. The thermal properties were evaluated using TGA/DTG. The FTIR showed the disappearance of the peaks responsible for the hemicelluloses and lignin. These results were confirmed by TGA which proved gradual elimination of non-cellulosic constituents. X-ray Diffractometer depicted an increase in crystallinity occasioned by sequential treatments to get the cellulose nanocrystals. Cellulose nanocrystals had a spherical shape with a diameter of 38nm as compared to the chemically purified cellulose which had a diameter of 76nm. The CNCs prepared with this method were seen to be less agglomerated and more crystalline thus possess a higher potential as bionanocomposite either for biomedical applications or for wastewater treatment among other industrial application. This approach also provides an opportunity for the sugar companies to effectively manage their waste product.

5.
Endocrinology ; 147(3): 1545-55, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16373415

RESUMO

The activity of hypothalamic GnRH neurons results in the intermittent release of GnRH required for reproductive function. This intermittent neurosecretory activity has been proposed to reflect integration of intrinsic properties of and synaptic input to GnRH neurons. Determining the relative impact of synaptic inputs at different locations on the GnRH neuron is difficult, if not impossible, using only experimental approaches. Thus, we used electrophysiological recordings and neuronal reconstructions to generate computer models of GnRH neurons to examine the effects of synaptic inputs at varying distances from the soma along dendrites. The parameters of the models were adjusted to duplicate measured passive and active electrophysiology of cells from mouse brain slices. Our morphological findings reinforce the emerging picture of a complex dendritic structure of GnRH neurons. Furthermore, analysis of reduced morphology models indicated that this population of cells is unlikely to exhibit low-frequency tonic spiking in the absence of synaptic input. Finally, applying realistic patterns of synaptic input to modeled GnRH neurons indicates that synapses located more than about 30% of the average dendrite length from the soma cannot drive firing at frequencies consistent with neuropeptide release. Thus, processing of synaptic input to dendrites of GnRH neurons is probably more complex than simple summation.


Assuntos
Células Dendríticas/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Neurônios/metabolismo , Sinapses/metabolismo , Algoritmos , Animais , Encéfalo/metabolismo , Eletrofisiologia , Proteínas de Fluorescência Verde/metabolismo , Imageamento Tridimensional , Cinética , Lisina/análogos & derivados , Lisina/metabolismo , Masculino , Camundongos , Modelos Anatômicos , Modelos Genéticos , Modelos Neurológicos , Neuropeptídeos/química , Distribuição Tecidual
6.
Endocrinology ; 139(6): 2774-83, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9607784

RESUMO

The purpose of this study was to determine the pattern and tempo of the open-loop reaugmentation of pulsatile GnRH release at the time of puberty in the male rhesus monkey. Episodic LH secretion from the in situ pituitary, in which responsiveness to GnRH was first heightened and subsequently sustained by priming with an i.v. intermittent infusion of the synthetic peptide, was used as an index of GnRH discharges. Ten male monkeys were castrated between 12 and 20 months of age, implanted with indwelling venous catheters, and housed in specialized cages that permitted remote access to the venous circulation with minimal restraint and without interfering with the light-dark cycle. Endogenous GnRH release was assessed by examining moment-to-moment changes in circulating LH concentrations measured at 12-min intervals for 7 h while GnRH priming was temporarily interrupted. A discharge of GnRH was inferred whenever a pulse of LH secretion was identified by a pulse detection program. Examination of nocturnal pulsatile GnRH release (1900-0200 h) was initiated as early as 14 months of age. GnRH release was assessed at 40-day intervals before 20 months of age and at 10-day intervals whenever possible thereafter. A simple algorithm was developed to identify the age at which a developmental increase in hypophysiotropic drive to the gonadotroph occurred. This was termed day zero and was considered to represent the age at which a pubertal mode of GnRH release was initiated. After the initiation of pubertal GnRH release was established, alternate nighttime and daytime (1100-1800 h) assessments of GnRH were performed. Before day zero, which was observed between 24 and 29 months of age, a stable, low frequency (<1 pulse/7 h), low amplitude pattern of pulsatile GnRH release was observed. Termination of the prepubertal mode of GnRH pulse generator activity was manifest as a relatively rapid nocturnal shift to a robust high-frequency pattern of activity. In some animals, the nocturnal acceleration to an adult GnRH pulse frequency (6-7 pulses/7 h) was attained within an epoch of only 30 days. Although initiation of the pubertal acceleration in nocturnal GnRH pulse generator activity seemed to be associated with an increase in GnRH pulse amplitude, it was not possible to decipher the subsequent developmental changes in this parameter. In some animals, the pattern of pulsatile GnRH release after the initiation of the pubertal acceleration was punctuated by periods of diminished activity, which seemed to be unrelated to the state of the pituitary-adrenal axis. These findings demonstrate that the neurobiological mechanisms that lead to the termination of the prepubertal mode of diminished GnRH release, and that therefore initiate the insidious process of puberty, have the potential to unfold with a surprisingly rapid time course. The extent to which the intrinsic tempo of the pubertal acceleration of pulsatile GnRH release in the agonadal situation is dampened by testicular feedback in the intact monkey remains to be established.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Macaca mulatta/crescimento & desenvolvimento , Macaca mulatta/metabolismo , Animais , Ritmo Circadiano/fisiologia , Hormônio Luteinizante/metabolismo , Masculino , Fluxo Pulsátil , Fatores de Tempo
7.
Endocrinology ; 141(10): 3731-6, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11014229

RESUMO

Central control of reproduction is governed by a neuronal pulse generator that underlies the activity of hypothalamic neuroendocrine cells that secrete GnRH. Bursts and prolonged episodes of repetitive action potentials have been associated with hormone secretion in this and other neuroendocrine systems. To begin to investigate the cellular mechanisms responsible for the GnRH pulse generator, we used transgenic mice in which green fluorescent protein was genetically targeted to GnRH neurons. Whole-cell recordings were obtained from 21 GnRH neurons, visually identified in 200-microm preoptic/hypothalamic slices, to determine whether they exhibit high frequency bursts of action potentials and are electrically coupled at or near the somata. All GnRH neurons fired spontaneous action potentials, and in 15 of 21 GnRH neurons, the action potentials occurred in single bursts or episodes of repetitive bursts of high frequency spikes (9.77 +/- 0.87 Hz) lasting 3-120 sec. Extended periods of quiescence of up to 30 min preceded and followed these periods of repetitive firing. Examination of 92 GnRH neurons (including 32 neurons that were located near another green fluorescent protein-positive neuron) revealed evidence for coupling in only 1 pair of GnRH neurons. The evidence for minimal coupling between these neuroendocrine cells suggests that direct soma to soma transfer of information, through either cytoplasmic bridges or gap junctions, has a minor role in synchronization of GnRH neurons. The pattern of electrical activity observed in single GnRH neurons within slices is temporally consistent with observations of GnRH release and multiple unit electrophysiological correlates of LH release. Episodes of burst firing of individual GnRH neurons may represent a component of the GnRH pulse generator.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/fisiologia , Neurônios/fisiologia , Área Pré-Óptica/fisiologia , Potenciais de Ação/fisiologia , Animais , Eletrofisiologia , Feminino , Proteínas de Fluorescência Verde , Técnicas In Vitro , Indicadores e Reagentes , Proteínas Luminescentes , Masculino , Camundongos , Camundongos Transgênicos/genética
8.
Endocrinology ; 141(1): 412-9, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10614664

RESUMO

GnRH neurons form the final common pathway for central control of reproduction, with regulation achieved by changing the pattern of GnRH pulses. To help elucidate the neurobiological mechanisms underlying pulsatile GnRH release, we generated transgenic mice in which the green fluorescent protein (GFP) reporter was genetically targeted to GnRH neurons. The expression of GFP allowed identification of 84-94% of immunofluorescently-detected GnRH neurons. Conversely, over 99.5% of GFP-expressing neurons contained immunologically detectable GnRH peptide. In hypothalamic slices, GnRH neurons could be visualized with fluorescence, allowing for identification of individual GnRH neurons for patch-clamp recording and subsequent morphological analysis. Whole-cell current-clamp recordings revealed that all GnRH neurons studied (n = 23) fire spontaneous action potentials. Both spontaneous firing (n = 9) and action potentials induced by injection of depolarizing current (n = 17) were eliminated by tetrodotoxin, indicating that voltage-dependent sodium channels are involved in generating action potentials in these cells. Direct intracellular morphological assessment of GnRH dendritic morphology revealed GnRH neurons have slightly more extensive dendrites than previously reported. GnRH-GFP transgenic mice represent a new model for the study of GnRH neuron structure and function, and their use should greatly increase our understanding of this important neuroendocrine system.


Assuntos
Marcação de Genes , Hormônio Liberador de Gonadotropina/metabolismo , Proteínas Luminescentes/genética , Neurônios/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Feixe Diagonal de Broca/citologia , Feixe Diagonal de Broca/metabolismo , Eletrofisiologia , Técnica Direta de Fluorescência para Anticorpo , Regulação da Expressão Gênica/fisiologia , Hormônio Liberador de Gonadotropina/genética , Proteínas de Fluorescência Verde , Imuno-Histoquímica , Camundongos , Neurônios/metabolismo , Neurônios/ultraestrutura , Técnicas de Patch-Clamp , Tetrodotoxina/farmacologia , Transgenes/genética
9.
J Clin Endocrinol Metab ; 89(5): 2275-80, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15126553

RESUMO

The pubertal amplification of GH secretion in primates has been thought to reflect an increase in gonadal steroid hormones due to gonadotropin stimulation induced by hypothalamic GnRH release. Previous studies in agonadal, peripubertal, male rhesus monkeys have estimated the age of GnRH activation (defined as d 0) using analyses of nocturnal, pulsatile LH patterns derived from sequential blood samples. Using samples from these earlier studies, secretory patterns of GH were analyzed using Cluster at approximately 30-d intervals in the youngest prepubertal ages and at approximately 10- to 20-d intervals in the period immediately preceding and following the onset of puberty. Pulse frequency, amplitude, and mean GH increased significantly between early prepubertal ages (up to 30 d before d 0) and the late prepubertal period (between -20 d and d 0). Pulsatile GH activity increased earlier than pulsatile LH secretion in four of five animals. These findings support the conclusion that pulsatile GH secretion increases developmentally in the absence of gonadal steroids. Furthermore, the present observation that the developmental increase in GH secretion occurs earlier than previously reported is consistent with the possibility that GH itself either directly or indirectly participates in the pubertal reinitiation of GnRH pulse generator activity.


Assuntos
Hormônio do Crescimento/metabolismo , Macaca mulatta/fisiologia , Orquiectomia , Envelhecimento/metabolismo , Animais , Ritmo Circadiano , Hormônio do Crescimento/sangue , Hormônio Luteinizante/metabolismo , Macaca mulatta/metabolismo , Masculino , Fluxo Pulsátil , Fatores de Tempo
10.
J Clin Endocrinol Metab ; 85(2): 808-14, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10690895

RESUMO

The factor(s) responsible for initiating the developmental increase in nocturnal gonadotropin-releasing hormone secretion, defining the onset of puberty, are not known. Although signals regulating prepubertal growth seem to be obvious candidates to control such a process, it is unclear whether prepubertal alterations occur in these growth-related factors such that they might provide the brain information on changing body size. Using samples analyzed previously describing the initiation of nocturnal pulsatile LH secretion in agonadal male monkeys (Endocrinology 139: 2774-2783, 1998), developmental changes in plasma concentrations of leptin, GH, and insulin-like growth factor I (IGF-I) were determined to test the hypothesis that an increase in circulating levels of one or all of these growth-derived signals precedes the onset of puberty. Hormone concentrations were determined in five juvenile males at 10-day intervals from approximately 60 days before and 50 days after the initiation of pulsatile nocturnal LH secretion. Leptin concentrations were determined in samples obtained at 1000 and 2200 h, 36 and 48 h before the nocturnal assessment of pulsatile LH. Mean nocturnal GH concentrations were determined from the sequential samples collected at night. IGF-I was determined in the 1000- or 2200-h presequential samples. Although daytime leptin concentrations did not increase developmentally, nocturnal leptin levels increased significantly during the 30 days before the onset of puberty. Furthermore, both nocturnal GH and IGF-I concentrations showed a significant sustained increase from the early prepubertal period to the 30 days preceding the onset of puberty. These data are the first to demonstrate an increase in nocturnal leptin and GH-induced IGF-I secretion prior to the onset of puberty in the agonadal male monkey and that these developmental changes occur independent of the gonadal influences. These findings provide justification for empirical investigation of the role of leptin and the GH axis, in particular IGF-I, in regulating developmental increases in pulsatile nocturnal gonadotropin-releasing hormone secretion initiating puberty in primates.


Assuntos
Genitália Masculina/fisiologia , Hormônio do Crescimento/sangue , Fator de Crescimento Insulin-Like I/análise , Leptina/sangue , Transdução de Sinais/fisiologia , Animais , Ritmo Circadiano , Hormônio Luteinizante/sangue , Macaca mulatta , Masculino , Concentração Osmolar , Fluxo Pulsátil
11.
Neuroscience ; 128(2): 443-50, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15350654

RESUMO

Episodic release of gonadotropin releasing hormone (GnRH) is obligatory for mammalian reproduction. The contribution of synaptic input to intermittent firing of GnRH neurons is unclear. GnRH neurons have very few synapses and most post-synaptic currents are small. Therefore, the impact of synaptic currents on firing in GnRH neurons was directly examined using simulated (S)-alpha-amino-3-hydroxy-5-methyl-isoxazolepropionic acid (AMPA)-like inputs applied with the method of dynamic current clamping. Tightly synchronized inputs and 50 ms bursts of excitatory input resulted in action potentials that were coincident with the stimulus. Neither input pattern resulted in sustained firing. When ongoing patterns of simulated inputs were applied over a range of parameters, action potentials were associated with clusters of AMPA-like inputs of 250 pS (approximately 15 pA amplitudes), while single inputs of 500 pS (approximately 30 pA amplitudes) resulted in action potentials. Ongoing inputs of 500 pS drove firing at 4-9 Hz. These findings provide evidence that small, simulated glutamatergic inputs can control firing in GnRH neurons and suggest that despite the small amplitudes, endogenous synaptic input mediated by glutamate may contribute to firing in GnRH neurons.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/fisiologia , Neurônios/fisiologia , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/metabolismo , Potenciais de Ação , Animais , Simulação por Computador , Estimulação Elétrica/métodos , Eletrofisiologia , Hipotálamo/citologia , Hipotálamo/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Modelos Neurológicos , Neurônios/metabolismo , Técnicas de Patch-Clamp , Tempo de Reação
12.
Neuroscience ; 124(2): 305-17, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-14980381

RESUMO

Granule cell activity in cerebellar cortex directly excites Purkinje cells via parallel fibers, but it also inhibits Purkinje cells via cerebellar cortical interneurons. This contribution of inhibitory interneurons to cerebellar cortical processing remains poorly understood. In the present study we examined the response properties of stellate cells in vitro to input patterns that may result from granule cell activity in vivo. We constructed input waveforms that represented the sum of inputs from all individual synapses and applied these waveforms to the soma of stellate cells during whole cell recordings in acute brain slices. The stimulus waveforms contained fluctuations in a broad range of frequencies and were applied at different amplitudes. To determine the contribution of synaptic shunting to stellate cell spike responses we applied the same input waveforms either as a simulated synaptic conductance using dynamic clamping or as a direct current injection stimulus. Only the dynamic clamp stimulus has the shunting properties of real synapses, i.e. leads to different-sized synaptic current as a function of membrane potential. We found that stellate cells spike with millisecond precision in response to fast temporal fluctuations in the total synaptic input. Transient increases in excitatory input frequency led to pronounced stellate cell spike responses, indicating that this pathway may be very responsive to even small assemblies of co-activated granule cells. This was observed regardless of whether the input waveform was applied as a conductance with dynamic clamping, or as a direct current injection. Thus the shunting properties of a conductance input did not play a major role in determining the control of precisely timed spiking. In contrast, a more tonic increase in excitatory conductance did not lead to a sustained spike response as obtained with prolonged positive current injection. However, even with tonic current injection the precision of spiking was lost, as previously observed. Overall, the synaptic response function of stellate cells suggests that this cell type may pick out transients in granule cell activity, and may generate precisely timed inhibition of Purkinje cells during behavior.


Assuntos
Potenciais de Ação/fisiologia , Cerebelo/citologia , Modelos Neurológicos , Neurônios/fisiologia , Potenciais de Ação/efeitos da radiação , Animais , Animais Recém-Nascidos , Cerebelo/fisiologia , Condutividade Elétrica , Estimulação Elétrica , Técnicas In Vitro , Masculino , Inibição Neural/fisiologia , Técnicas de Patch-Clamp/métodos , Ratos , Ratos Sprague-Dawley , Sinapses/fisiologia , Sinapses/efeitos da radiação , Fatores de Tempo
13.
J Endocrinol ; 163(2): 235-41, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10556773

RESUMO

The hypothalamic component of the reproductive axis in vertebrates is comprised of a pulse generator that stimulates the release of GnRH. Several lines of evidence are in agreement that the activity of this pulse generator is intermittent and results in the pulsatile pattern of GnRH and LH release. During a recent investigation of the re-initiation of LH secretion in the agonadal, prepubertal male monkey, we observed a daytime profile of LH secretion, which suggests an apulsatile mode of GnRH release. The first purpose of this study was to describe this observation of apulsatile LH release during the peripubertal transition. Furthermore, we have explored the dependence of this form of LH secretion on GnRH release. Five male rhesus monkeys (Macaca mulatta) were castrated prepubertally and were treated with an intermittent infusion of GnRH to prematurely sensitize the juvenile pituitary to endogenous GnRH release. Alternate daytime (1100-1800 h) and nighttime (1900-0200 h) assessments of LH release were performed at 10-day intervals throughout the peripubertal transition with samples taken every 12 min. In a second experiment, four agonadal males which demonstrated an apulsatile profile of LH release were maintained on an infusion of physiological saline and were treated with the GnRH antagonist Nal-Glu (i.m., 500 microgram/kg). Circulating levels of LH were determined 22 h after antagonist treatment. In peripubertal animals, circulating levels of LH were similar between morning and evening assessments. However, pulse frequency was significantly lower during the daytime. GnRH antagonist reduced LH levels by 72% and a similar reduction in response to an exogenous GnRH test stimulus occurred. These findings suggest an apulsatile mode of GnRH release.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Macaca mulatta/metabolismo , Periodicidade , Animais , Ritmo Circadiano/fisiologia , Hormônio Liberador de Gonadotropina/antagonistas & inibidores , Hormônio Luteinizante/sangue , Hormônio Luteinizante/metabolismo , Masculino , Orquiectomia
14.
J Endocrinol ; 160(1): 35-41, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9854174

RESUMO

The major purpose of this study was to characterize the open-loop frequency of pulsatile GnRH release in the female rhesus monkey at an age (15-20 months) when the prepubertal restraint on the hypothalamic-pituitary axis is maximally imposed. Additionally, evidence for pulsatile GnRH release in agonadal males of comparable age was also sought. Episodic LH secretion from the pituitary was used as an indirect index of GnRH discharges. In order to maximize the sensitivity of this in situ bioassay, the responsiveness of the pituitary gonadotrophs was usually first heightened by an i.v. intermittent infusion of the synthetic peptide. Monkeys (five females, three males) were castrated between 9 and 14 months of age, implanted with indwelling venous catheters, fitted with nylon jackets and housed in specialized cages that permitted remote access to the venous circulation with minimal restraint and without interruption of the light-darkness cycle. In females, LH secretion was generally assessed at 20-day intervals during alternate nighttime (1900-0200 h) and daytime (0700-1400 h) windows. In males, LH was assessed less frequently and only at night. The mean frequency of pulsatile LH release in agonadal prepubertal females was 4 pulses/7 h during the night and 2 pulses/7 h during the day. These findings indicate that, prior to puberty in the female monkey, the GnRH pulse generator operates at a relatively slow frequency and is subjected to diurnal modulation. In males, evidence for robust pulsatile GnRH release was not observed. The striking difference in activity of the GnRH pulse generator in agonadal prepubertal male and female monkeys reinforces the view that the ontogeny of the hypothalamic drive to the pituitary-gonadal axis in higher primates, including man, is sexually differentiated.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Hormônio Luteinizante/sangue , Hipófise/metabolismo , Maturidade Sexual/fisiologia , Animais , Feminino , Macaca mulatta , Masculino , Orquiectomia , Ovariectomia , Taxa Secretória , Caracteres Sexuais
15.
Mutat Res ; 30(3): 365-74, 1975 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1238902

RESUMO

Dominant-lethal effects of 10 mg/kg methylmercuric hydroxide were studied in male mice from two hybrid stocks and in females from one of these stocks. Two other compounds, mercuric chloride (2 mg/kg) and cadmium chloride (2 mg/kh), were studied only in females for dominant-lethal (in one hybrid stock) and reproductive capacity effects (in two hybrid and one mixed stocks). All compounds were administered in a single intraperitoneal injection. When males of one of the two stocks studied were treated with methylmercuric hydroxide, the females to which they were mated exhibited a slight reduction in the total number of implantations and in the number of living embryos. These reductions were accompanied by a very small increase in the incidence of dead implantations. In females, cadmium chloride had no detectable dominant-lethal or other fertility effects, except superovulation. On the other hand, the two mercury compounds slightly reduced the numbers of implants and living embryos in females subjected to dominant-lethal studies. The two mercury compounds also induced a slight reduction in that long-term reproductive performance of one stock of females. These results and those reported earlier by others, indicate that the mercury compounds studied so far are not potent inducers of dominant-lethal mutations in male and female mice. It is not clear whether the small effects on male or female fertility induced in some cases, particularly the increase in dead implantations and reductions in the number of living embryos, were attributable to dominant-lethal mutations or to nongenetic causes.


Assuntos
Cádmio/farmacologia , Fertilidade/efeitos dos fármacos , Genes Dominantes , Genes Letais , Mercúrio/farmacologia , Animais , Implantação do Embrião/efeitos dos fármacos , Feminino , Tamanho da Ninhada de Vivíparos/efeitos dos fármacos , Masculino , Compostos de Metilmercúrio/farmacologia , Camundongos , Mutagênicos , Mutação , Gravidez , Fatores Sexuais , Fatores de Tempo
16.
Mutat Res ; 30(3): 355-64, 1975 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-172786

RESUMO

Females from (C3H X 101)F1 and a mixed stock were injected intraperitoneally with either 25 or 50 mg/kg isopropyl methanesulfonate (IMS) or Hanks' solution 4-5 h after the midpoint of the dark period during which mating occurred. It was determined that at the time of treatment the great majority of oocytes were undergoing second meiotic division. For comparison, the same doses of IMS were given to females treated within 3-5 days prior to mating (predominantly dictyate oocytes) or to males treated within 4-5 days prior to mating (sperm in vas and epididymis). The frequencies of presumed dominant lethals induced by 50 mg/kg IMS in sperm treated in vas and epididymis, dictyate oocytes, and germ cells in mated females are 22%, 19%, and 79%, respectively, for (C3H X 101)F1 and 26%, 30%, and 76% for the other stock. Clearly, in both stocks, effects in mated females, when both female and male germ cells were treated, are relatively much higher than the added effects on dyctyate oocytes and spermatozoa. This is also true for the 25 mg/kg dose.


Assuntos
Genes Dominantes , Genes Letais , Células Germinativas/efeitos dos fármacos , Mesilatos/toxicidade , Mutação , Animais , Copulação , Feminino , Injeções Intraperitoneais , Masculino , Meiose/efeitos dos fármacos , Mesilatos/administração & dosagem , Camundongos , Oócitos/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos
17.
Mutat Res ; 34(2): 259-70, 1976 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-175270

RESUMO

The relative sensitivities of various postcopulation-precleabage and pronuclear stages to dominant-lethal effects of isopropyl methanesulfonate (IMS), ethyl methanesulfonate (EMS), and triethylenemelamine (TEM) were investigated. The pattern of sensitivity differed with the chemical. IMS was most effective when pronuclear formation was already completed and the majority of the zygotes were presumably undergoing DNA synthesis. EMS, on the other hand, induced its most pronounced effects when eggs in the course of second meiotic division and zygotes in early pronuclear stages were treated. The greatest effect of TEM was observed when zygotes were treated at the early pronuclear stage. EMS and TEM, in contrast to IMS, are similar to radiations in that zygotes undergoing DNA synthesis are more resistant to them than are the early pronuclear stages. In the case of IMS, effects induced in the most sensitive postcopulation-precleavage stage were 6 to 9 times greater than in the most sensitive precopulatory dictyate oocytes or male germ cells. On the other hand, in the case of EMS and TEM, the most sensitive precopulatory male germ cells, but not the dictyate oocytes, were more sensitive than the most sensitive postcopulation stages.


Assuntos
Mesilatos/farmacologia , Oócitos/metabolismo , Óvulo/metabolismo , Espermatócitos/metabolismo , Espermatozoides/metabolismo , Trietilenomelamina/farmacologia , Zigoto/metabolismo , Alquilantes , Animais , DNA/metabolismo , Metanossulfonato de Etila/farmacologia , Feminino , Genes Dominantes , Genes Letais , Masculino , Meiose , Camundongos
18.
Neurotoxicol Teratol ; 10(2): 155-67, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3398824

RESUMO

Five laboratories collaborated in the evaluation of detection limits of different testing concepts in behavioral teratology. In one laboratory, rat dams were treated by gavage with five doses of methylmercury (0.0, 0.25, 0.05, 0.5, and 5.0 mg/kg/day). The treatment period was restricted to days 6 to 9 of gestation. The usual reproduction parameters were assessed in the dams. The offspring (88-99 per group) were subjected to a routine developmental and behavioral testing battery. After completion of these tests, random samples of the animals were further investigated in four other laboratories using the following techniques: auditory startle habituation, visual discrimination and figure-8 activity monitor; wheel-shaped activity monitor and spatial alternation operant conditioning; two-compartment locomotor activity, passive avoidance and male ultrasonic vocalization during sexual behavior; assays of the weight of different brain areas, their glial fibrillary acidic (GFA) protein and S-100 protein concentration. The following dose-dependent effects were noted in ascending dose sensitivity order: delayed vaginal opening; increased and more variable passiveness in spatial alternation; impaired swimming behavior, increased GFA protein concentration in the cerebellar vermis; increased auditory startle amplitude, decreased intertrial interval pokes in the visual discrimination test, increased percentage of visits in passive area of figure-8 activity monitor, increased path iteration frequencies and decreased local activity in the wheel-shaped activity monitor, decreased locomotor activity in the two-compartment monitor, increased cerebellar vermis weight, and decreased S-100 protein in the hippocampus. Therefore, this study showed comparable sensitivities for the behavioral testing battery, for some automated multiparametric test systems and for the neurochemical assays.


Assuntos
Comportamento Animal/efeitos dos fármacos , Compostos de Metilmercúrio/toxicidade , Sistema Nervoso/efeitos dos fármacos , Teratogênicos , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Química Encefálica , Aprendizagem por Discriminação/efeitos dos fármacos , Feminino , Locomoção/efeitos dos fármacos , Masculino , Mercúrio/sangue , Gravidez , Ratos , Reflexo de Sobressalto/efeitos dos fármacos , Comportamento Sexual Animal/efeitos dos fármacos , Vocalização Animal/efeitos dos fármacos
19.
Aust Health Rev ; 19(1): 17-26, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-10157533

RESUMO

The Industry Commission has carried out Australia's largest inquiry into charities. It was, from the point of view of charities, an unsatisfactory operation, all the more so since it was not clear why the task had been given to the commission. This article examines the commission's work in three ways: the overall relationship between government and charities; the commission's proposed major reforms; and the minor reforms.


Assuntos
Instituições de Caridade/organização & administração , Relações Interinstitucionais , Seguridade Social , Austrália , Instituições de Caridade/economia , Estudos de Avaliação como Assunto , Governo , Indústrias , Impostos
20.
Clin Pharmacol Ther ; 91(5): 856-62, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22453191

RESUMO

The pharmacokinetics and pharmacodynamics of a highly concentrated cyclodextrin-based intranasal (i.n.) midazolam formulation containing the absorption-enhancer chitosan were studied in 12 healthy volunteers and compared with intravenous (i.v.) midazolam. The pharmacodynamic (PD) effects were assessed using quantitative electroencephalography (EEG). Maximal plasma concentrations of 63 and 110 ng/ml were reached at 8.4 and 7.6 min after 3 and 6 mg i.n. midazolam, respectively. After 5 mg i.v. and 6 and 3 mg i.n. midazolam, the times to onset of significant EEG effects in the ß2 band (18-25 Hz) were 1.2, 5.5, and 6.9 min, respectively, and the times to loss of response to auditory stimuli were 3.0, 8.0, and 15.0 min, respectively. A sigmoid maximum-effect (E(max)) model indicated disequilibrium between plasma and effect-site concentrations, with equilibration half-lives of 2.1-4.8 min. The observed pharmacokinetic-PD (PK-PD) properties suggest that i.n. midazolam deserves to be evaluated as an easy and noninvasive method of administering a first benzodiazepine dose, e.g., in out-of-hospital emergency settings with no immediate i.v. access.


Assuntos
Eletrocardiografia/efeitos dos fármacos , Midazolam/farmacologia , Midazolam/farmacocinética , Administração Intranasal , Adulto , Estudos Cross-Over , Método Duplo-Cego , Humanos , Masculino , Midazolam/administração & dosagem , Pessoa de Meia-Idade , Modelos Biológicos
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