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1.
Plant Biol (Stuttg) ; 25(5): 671-680, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37164339

RESUMO

Flower morphology is considered an important factor in species diversification because it may influence the efficiency of pollination in different ways (e.g. attraction and mechanical fit with different groups of pollinators). In the present study, we quantified the variation in flower morphology (i.e. shape and size) of the diverse South American genus Jaborosa Juss. (Solanaceae) in relation to contrasting pollination modes: rewarding pollination either by moths or by generalist small insects versus brood-site deceptive pollination by saprophilous flies. We examined variations of flower morphology in frontal (pollinator attraction) and sagittal (functional fit with pollinators) views in 12 Jaborosa species using geometric morphometric methods and comparative approaches to infer whether flower shape evolution, not attributable to flower allometry or phylogenetic relationship, is associated with shifts in pollination modes. We found remarkable variation in flower morphology among both Jaborosa species and pollination modes, largely in sagittal view. Evolutionary trends in shape of fly-pollinated flowers were mainly attributable to changes in developmental trajectories. Variation in flower architecture facilitated differential pollen placement - on the proboscis of moths, and either on the back or ventral region of saprophilous flies - promoting diversification of the genus. Diversification of shape, independent of size, in most of the studied Jaborosa species would indicate adaptation to contrasting pollination modes.


Assuntos
Dípteros , Mariposas , Solanaceae , Animais , Filogenia , Evolução Biológica , Polinização , Flores/anatomia & histologia
2.
Nanoscale Adv ; 5(9): 2462-2469, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37143806

RESUMO

The development of time-resolved transmission electron microscopy (TEM), ultrafast electron spectroscopy and pulsed X-ray sources relies on the realization of stable and high brightness sources of ultra-short electron bunches with a long service time. The flat photocathodes implanted in thermionic electron guns have been replaced by Schottky-type or cold-field emission sources driven by ultra-fast laser. Recently, lanthanum hexaboride (LaB6) nanoneedles have been reported to have high brightness and high emission stability when working in a continuous emission mode. Here, we prepare nano-field emitters from bulk LaB6 and we report on their use as ultra-fast electron sources. Using a high repetition rate laser in the infrared range, we present different field emission regimes as a function of the extraction voltage and laser intensity. The properties of the electron source (brightness, stability, energy spectrum and emission pattern) are determined for the different regimes. Our results show that LaB6 nanoneedles can be used as ultrafast and ultra-bright sources for time-resolved TEM, with better performances as compared to metallic ultra-fast field-emitters.

3.
Plant Biol (Stuttg) ; 25(3): 403-410, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36744723

RESUMO

Invasive plants displaying disparate pollination environments and abiotic conditions in native and non-native ranges provide ideal systems to test the role of different ecological factors driving flower colour variation. We quantified corolla reflectance of the ornithophilous South American Nicotiana glauca in native populations, where plants are pollinated by hummingbirds, and in populations from two invaded regions: South Africa, where plants are pollinated by sunbirds, and the Balearic island of Mallorca, where plants reproduce by selfing. Using visual modelling we examined how corolla reflectance could be perceived by floral visitors present in each region. Through Mantel tests we assessed a possible association between flower colour and different abiotic factors. Corolla reflectance variation (mainly along medium to long wavelengths, i.e. human green-yellow to red colours) was greater among studied regions than within them. Flower colour was more similar between South America and South Africa, which share birds as pollinators. Within invaded regions, corolla reflectance variation was lower in South Africa, where populations could not be distinguished from each other by sunbirds, than in Spain, where populations could be distinguished from each other by their occasional visitors. Differences in corolla colour among populations were partially associated with differences in temperature. Our findings suggest that shifts in flower colour of N. glauca across native and invaded ranges could be shaped by changes in both pollination environment and climatic factors. This is the first study on plant invasions considering visual perception of different pollinators and abiotic drivers of flower colour variation.


Assuntos
Nicotiana , Polinização , Animais , Humanos , Cor , Plantas , Flores , Aves , Percepção
4.
Schweiz Arch Tierheilkd ; 162(4): 223-234, 2020 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-32234692

RESUMO

INTRODUCTION: The oral treatment of feline hyperthyroidism with antithyroid drugs often results in gastrointestinal side effects (10-20%). To date only oral formulations are approved although the oral application is not tolerated by all cats. Transdermal therapy can be an alternative. Nanocarriers could be used to ensure adequate transport of active agents through the skin. The present pilot study investigated the efficacy and safety of a novel dermal formulation of thiamazole for the treatment of feline hyperthyroidism. For the first time, amphiphilic dendritic core-multishell-nanocarriers were used. Cats with T4 values ≥ 4.0 µg/dl or a T4 value from 3.0-4.0 µg/dl and defined clinical findings were recruited. The euthyroid range for the T4 value was defined from ≥ 0.8 and ≤ 4.0 µg/dl. A total of 24 hyperthyroid cats were included and treated with thiamazole ointment for three weeks (24 cats) up to eight weeks (12 cats). The treatment success was 50% after three weeks and 41,7% after eight weeks. Cats that were within the euthyroid range required after three weeks a mean total dose of 1,09 mg/kg/d (0,68-1,7 mg/kg/d, 12/24) and after eight weeks 1,65 mg/kg/d (1,49-2,04 mg/kg/d, 5/12). No side effects were observed during the three resp. eight-week study period. Variations of the T4 value in companion cats in the same household were comparable to those of an independent control group. Thiamazole ointment based on nanocarriers is suitable for the treatment of feline hyperthyroidism.


INTRODUCTION: Le traitement oral de l'hyperthyroïdie féline avec des médicaments antithyroïdiens entraîne souvent des effets secondaires gastro-intestinaux (10 à 20% des cas). À ce jour, seules les formulations orales sont approuvées, bien que l'application orale ne soit pas tolérée par tous les chats. La thérapie transdermique peut être une alternative. Des nanoporteurs pourraient être utilisés pour assurer un transport adéquat des agents actifs à travers la peau. La présente étude pilote a examiné l'efficacité et l'innocuité d'une nouvelle formulation cutanée de thiamazole pour le traitement de l'hyperthyroïdie féline. Pour la première fois, des nanoporteurs à noyau multicellulaire dendritiques amphiphiles ont été utilisées. Des chats avec des valeurs T4 ≥ 4,0 µg/dl ou une valeur T4 de 3,0­4,0 µg/dl et un tableau clinique définis ont été recrutés. La gamme euthyroïdienne pour la valeur T4 a été définie entre ≥ 0,8 et ≤ 4,0 µg/dl. Un total de 24 chats hyperthyroïdiens ont été inclus et traités avec une pommade au thiamazole pendant une période allant de trois semaines (24 chats) jusqu'à huit semaines (12 chats). Le succès du traitement était de 50% après trois semaines et de 41,7% après huit semaines. Les chats qui se trouvaient dans la gamme euthyroïdienne avaient besoin après trois semaines d'une dose totale moyenne de 1,09 mg/kg/j (0,68­1,7 mg/kg/j, 12/24) et après huit semaines 1,65 mg/kg/j (1,49-2,04 mg/kg/j, 5/12). Aucun effet secondaire n'a été observé pendant les trois respectivement les huit semaines de l'étude. Les variations de la valeur T4 chez les chats vivant dans le même ménage étaient comparables à celles d'un groupe témoin indépendant. La pommade au thiamazole à base de nanoporteurs convient au traitement de l'hyperthyroïdie féline.


Assuntos
Doenças do Gato/tratamento farmacológico , Hipertireoidismo/veterinária , Tiroxina/administração & dosagem , Administração Cutânea , Animais , Antitireóideos/administração & dosagem , Gatos , Portadores de Fármacos , Hipertireoidismo/tratamento farmacológico , Nanotecnologia , Pomadas/química , Pomadas/uso terapêutico , Projetos Piloto , Resultado do Tratamento
5.
Mol Phylogenet Evol ; 132: 90-99, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30508630

RESUMO

'Gradual' vs 'punctuated' and 'unidirectional' (only lengthening) vs. 'bidirectional'(lengthenings and shortenings) modes of evolution are explanations that compete to explain adaptive changes of flower tube length in angiosperm. The nightshade genus Salpichroa Miers, with 21 species mostly growing in the tropical Andes of southern South America, has the opportune qualities of including nearly 15-fold inter-specific variation in corolla tube length, as well as one species that is a candidate for participating in evolutionary escalation with the longest-billed hummingbird, Ensifera ensifera. We reconstructed the phylogenetic relationships using five molecular markers, the two plastid markers trnD-trnT and trnL, and three nuclear markers, ITS and two COSII, and estimated divergence times of the genus in order to reconstruct the history of both corolla tube length and pollination mode (i.e. hummingbirds, moths or multiple). We used comparative methods to determine whether corolla tube elongation/shortening is associated with shifts in pollination mode and to test, modes and rates of corolla tube change. We found evidence of both lengthening and shortening of corolla tubes. Evolutionary rates are consistent with rapid corolla tube length transitions that are only partly associated with shifts in pollination mode. Though 'punctuated' evolution (i.e. large changes predominantly at speciation events) explained corolla changes in the whole genus, 'gradual' evolution (i.e. gradual changes during a coevolutionary race with the same pollinator) was a better explanation for the change in the long-flowered clade, mostly pollinated by hummingbirds.


Assuntos
Evolução Biológica , Flores/fisiologia , Polinização , Solanaceae/fisiologia , Animais , Aves/fisiologia , Flores/anatomia & histologia , Análise dos Mínimos Quadrados , Mariposas/fisiologia , Filogenia
6.
Plant Biol (Stuttg) ; 21(2): 206-215, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30317685

RESUMO

Phenotypic intermediacy is an indicator of putative hybrid origin and has provided the main clues to discovering hybrid plants in nature. Mandevilla pentlandiana and M. laxa (Apocynaceae) are sister species with clear differences in floral phenotype and associated pollinator guilds: diurnal Hymenoptera and nocturnal hawkmoths, respectively. The presence of individuals with intermediate phenotypes in a wild population raises questions about the roles of visual and olfactory signals (i.e. corolla morphology and floral fragrances) as barriers to interbreeding, and how the breakdown of floral isolation occurs. We examined phenotypic variation in a mixed Mandevilla population, analysing the chemical composition of floral fragrances, characterising floral shape through geometric morphometrics and assessing individual grouping through taxonomically relevant traits and an unsupervised learning algorithm. We quantified the visitation frequencies of floral visitors and tracked their foraging movements using pollen analogues. The presence of morphologically intermediate individuals and pollen analogue movement suggested extensive hybridisation between M. laxa and M. pentlandiana, along with asymmetrical rates of backcrossing between these putative hybrids and M. laxa. Floral volatiles from putative hybrid individuals showed a transgressive phenotype, with additional compounds not emitted by either parental species. Our results suggest the presence of a hybrid swarm between sympatric M. pentlandiana and M. laxa and indicate that initial hybridisation events between these parental species are rare, but once they occur, visits between putative hybrids and M. laxa are common and facilitate continued introgression.


Assuntos
Apocynaceae/anatomia & histologia , Flores/anatomia & histologia , Polinização , Isolamento Reprodutivo , Animais , Hibridização Genética , Himenópteros , Mariposas , Odorantes , Fenótipo , Pólen/fisiologia , Especificidade da Espécie
7.
Mater Today Chem ; 14: 100195, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32289101

RESUMO

Schiff bases are versatile organic compounds which are widely used and synthesized by condensation reaction of different amino compound with aldehydes or ketones known as imine. Schiff base ligands are considered as privileged ligands as they are simply synthesized by condensation. They show broad range of application in medicine, pharmacy, coordination chemistry, biological activities, industries, food packages, dyes, and polymer and also used as an O2 detector. Semicarbazone is an imine derivative which is derived from condensation of semicarbazide and suitable aldehyde and ketone. Imine ligand-containing transition metal complexes such as copper, zinc, and cadmium have shown to be excellent precursors for synthesis of metal or metal chalcogenide nanoparticles. In recent years, the researchers have attracted enormous attention toward Schiff bases, semicarbazones, thiosemicarbazones, and their metal complexes owing to numerous applications in pharmacology such as antiviral, antifungal, antimicrobial, antimalarial, antituberculosis, anticancer, anti-HIV, catalytic application in oxidation of organic compounds, and nanotechnology. In this review, we summarize the synthesis, structural, biological, and catalytic application of Schiff bases as well as their metal complexes.

8.
J Fluoresc ; 27(3): 841-851, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28101797

RESUMO

Some nickel(II) and zinc(II) complexes of the type [Ni(L)(phen/bipy)]X (1a-6a) and [Zn(L) (phen/bipy)]X (1b-6b) (where L = 2-{(E)-[(4-trimethylsilylethynylphenyl)imino]methyl}-4-(4-nitro phenylethynyl)phenol; phen = 1, 10-phenanthroline, bipy = 2, 2´-bipyridine; X = ClO4-, BF4-, PF6-) have been prepared and characterized on the basis of elemental analyses, FTIR, 1H NMR and mass spectral studies. The molecular structure of L was determined by single crystal X-ray diffraction studies. The electrochemical behaviour of the Ni(II) complexes indicate that the phen complexes appears at more positive potential as compared to those for bipy complexes, as a consequence of its strong π-acidic character. TGA was carried out to study the thermal behavior of the complexes. Room temperature luminescence is observed for all complexes corresponds to π â†’ π* ILCT transition. The size of the counter anion and heterocyclic coligands phen and bipy shows marked effect on emission properties of the complexes.

9.
J Fluoresc ; 26(6): 2033-2040, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27524379

RESUMO

Copper(I) complexes of the formula [Cu(L)(PPh3)2]X (1-4) (X = Cl(1), ClO4(2), BF4(3) and PF6(4)) [where L = N-(2-{[(2E)-2-(4-nitrobenzylidenyl)hydrazinyl]carbonyl}phenyl)benzamide; PPh3 = triphenylphosphine] have been prepared by the condensation of N-[2-(hydrazinocarbonyl)phenyl]benzamide with 4-nitrobenzaldehyde followed by the reaction with CuCl, [Cu(MeCN)4]ClO4, [Cu(MeCN)4]BF4 and [Cu(MeCN)4]PF6 in presence of triphenylphosphine as a coligand. Complexes 1-4 were then characterized by elemental analyses, FTIR, UV-visible and 1H NMR spectroscopy. Mononuclear copper(I) complexes 1-4 were formed with L in its keto form by involvement of azomethine nitrogen and the carbonyl oxygen along with two PPh3 groups. A single crystal X-ray diffraction study of the representative complex [(Cu(L)(PPh3)2]CIO4 (2) reveals a distorted tetrahedral geometry around Cu(I). Crystal data of (2): space group = C2/c, a = 42.8596 (9) Å, b = 14.6207 (3) Å, c = 36.4643 (7) Å, V = 20,653.7 (7) Å3, Z = 16. Complexes 1-4 exhibit quasireversible redox behaviour corresponding to a Cu(I)/Cu(II) couple. All complexes show blue-green emission as a result of fluorescence from an intra-ligand charge transition (ILCT), ligand to ligand charge transfer transition (LLCT) or mixture of both. Significant increase in size of the counter anion shows marked effect on quantum efficiency and lifetime of the complexes in solution.

10.
Int J Endocrinol ; 2012: 420370, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22973308

RESUMO

Thyroid function regulates lipid metabolism. Despite the fact that T2DM is more prevalent in the elderly, often associates with thyroid dysfunction and increases cardiovascular risk both per se and via high TC and LDL-C levels, the association of the latter with FT(3) and FT(4) levels has not yet been fully investigated in T2DM. While trying to fill this gap in 296 elderly outpatients with T2DM, we found that TC and LDL-C correlated negatively with FT(4) and positively with FT(3). When divided according to treatment by oral hypoglycaemic agents (OHA) and insulin (IT), they reacted differently with respect to investigated associations: in the OHA's TC and LDL-C correlated negatively with FT(4) and showed no association with FT(3), whereas, in the IT's TC and LDL-C correlated positively with FT(3) and negatively with FT(4). When controlled for possible confounding factors, these associations did not change in the IT's but were missing in the OHA's. Recent literature reports upon complex hypothalamic and peripheral interactions between T2DM and thyroid, and suggests T(3) to enhance cholesterol synthesis and to have a role in insulin resistance states. Further investigations are needed to understand the intimate mechanisms of lipid metabolism in T2DM with respect to thyroid function.

11.
J Nanosci Nanotechnol ; 12(5): 3788-98, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22852308

RESUMO

We herein report an economical and facile technique for the synthesis of hierarchical nanostructures of Cu doped CdS nanostructures by microwave assisted solvothermal technique using a household microwave oven. We attempted to establish the effect of variation of solvents ratio on the morphological and optical properties of the obtained nanoscale structures. The field emission characteristics of the copper doped CdS nanoarchitecture have been studied and the turn on field is found to be 2.8 V/microm for an emission current density of approximately 0.1 microA/cm2. Emission current stability is determined at the preset current of approximately 1 microA and approximately 10 microA for the stable duration of approximately 4 hrs. The observed field emission results envisage the possibility of using the present emitter in the field emission sources. We believe that this is a unique report on the synthesis as well as field emission studies of copper doped CdS nanostructures. Photocatalytic dye degradation ability of the Cu doped CdS nanostructures is observed to be less than the undoped CdS counterparts.

12.
Nanoscale ; 4(2): 645-51, 2012 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-22159298

RESUMO

High-quality self-assembled V(2)O(5) nanofiber-bundles (NBs) are synthesized by a simple and direct hydrothermal method using a vanadium(v) hydroxylamido complex as a vanadium source in the presence of HNO(3). The possible reaction pathway for the formation of V(2)O(5) NBs is discussed and demonstrated that HNO(3) functions both as an oxidizing and as an acidification agent. V(2)O(5) NBs are single-crystals of an orthorhombic phase that have grown along the [010] direction. A bundle is made of indefinite numbers of homogeneous V(2)O(5) nanofibers where nanofibers have lengths up to several micrometres and widths ranging between 20 and 50 nm. As-prepared V(2)O(5) NBs display a high electrochemical performance in a non-aqueous electrolyte as a cathode material for lithium ion batteries. Field emission properties are also investigated which shows that a low turn-on field of ∼1.84 V µm(-1) is required to draw the emission current density of 10 µA cm(-2).


Assuntos
Cristalização/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos de Vanádio/química , Condutividade Elétrica , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
13.
Plant Biol (Stuttg) ; 11(4): 506-14, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19538389

RESUMO

We studied gland morphology, anatomy and the chemical composition of the floral fragrance in the sweat bee-pollinated orchid Cyclopogon elatus. This is apparently the first such analysis for any Cyclopogon species, and one of very few studies in which both odour and osmophore are characterised in a nectar-rewarding orchid. Structures responsible for floral scent production were localised with neutral red staining and histochemical assays for lipids and starch. Their morphology and anatomy were studied with scanning electron microscopy and light microscopy thin sections, respectively. Fragrance samples were collected using SPME fibres and analysed with GC-MS. Anatomical evidence suggests that two parallel oval-shaped patches of unicellular trichomes on the abaxial surface of the labellum are osmophores. These are rich in stored lipids, while the parenchyma surrounding the vascular bundles contains starch. Only freshly opened flowers produced odours, while buds and withered flowers lacked scent. The chemical composition of the odour was dominated (>99.8%) by a single compound, trans-4,8-dimethyl-nona-1,3,7-triene (DMNT). Gland anatomy and position on the outside of the perianth are unusual for scent glands in general. The presence of DMNT, a nearly ubiquitous compound in herbivore-induced vegetative emissions and one of the major floral volatiles of Yucca, is not surprising in view of hypotheses on the evolutionary origin of flower scents, suggesting that wound volatiles are utilised as kairomonal attractants by florivores whose activities result in pollination.


Assuntos
Flores/fisiologia , Odorantes , Orchidaceae/fisiologia , Flores/ultraestrutura , Microscopia Eletrônica de Varredura , Orchidaceae/ultraestrutura
14.
Actas Esp Psiquiatr ; 36(4): 210-7, 2008.
Artigo em Espanhol | MEDLINE | ID: mdl-18427997

RESUMO

The high prevalence of psychiatric morbidity in primary care, the growing perception of the need for specialized help by the least severe patients and the lack of accuracy in referrals, contribute to the increasing overload in mental health services. So it seems necessary to design diagnostic tools in order to improve the detection of more severe patients and to help in the referral decision. With this purpose in mind, we have designed the multidimensional heteroadministrated Scale Referral Criteria for Mental Health (CRMH). This paper presents the preliminary results of a pilot study on its application in a sample of 198 patients by a group of Primary Care Physicians (PCP). The data show the detection of a high percentage of potential psychiatric patients (46.9%) and 4% of patients who having the possibility of being referred. The results also illustrate the low ability of PCP to detect these disorders. CRMH has a moderate correlation with the General Health Questionnaire (GHQ) and with detection of psychopathology by PCP. Other factors, apart from clinical severity evaluated through CRMH, possibly belonging to doctor-patient relationship, which should be analyzed, seem to influence the mental health referral. In a future article, we will present the validation of this scale in our care setting.


Assuntos
Transtorno Bipolar/diagnóstico , Transtorno Bipolar/terapia , Serviços de Saúde Mental , Atenção Primária à Saúde , Encaminhamento e Consulta , Esquizofrenia/diagnóstico , Esquizofrenia/terapia , Inquéritos e Questionários , Adulto , Manual Diagnóstico e Estatístico de Transtornos Mentais , Progressão da Doença , Feminino , Humanos , Masculino
15.
Phys Med ; 21 Suppl 1: 35-8, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17645991

RESUMO

Results of aboratory evaluations are presented of the dual-head scintimammography system using two opposed and co-registered compact gamma heads. The system is intended for clinical studies imaging suspicious lesions in a compressed breast. The studies were performed using 5 cm and 6 cm compressed breast phantoms with lesion sizes from 6 to 10 mm and lesion to breast tissue activity ratios from 6 to 10. Two imagers with a field-of-view (FOV) of 15 cmx20 cm were placed on the opposite sides of the breast phartoms. In some studies anthropomorphic torso phantom was used to simulate realistic scatter gamma radiation field. Two types of parallel-hole lead collimators were employed. Combining the co-registered images from both detector heads resulted in an over two-fold increase in lesioin contrast in the central plane of the phantom and substantially increased detection sensitivity over the whole breast volume, especially of asymmetrically placed small lesions. The results confirm the important advantage of a co-registoed two-head scintimammography system over a single head system in lesion detection and localization.

16.
J Endocrinol Invest ; 28(11 Suppl Proceedings): 78-83, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16760631

RESUMO

Extraterrestrial exploration has gone on for decades before reversible testicular failure was shown to be a consequence of space flight in humans and animals at the end of the XXth century. This phenomenon was initially thought to depend on the psycho-physical stress expected to derive from a decidedly unusual environment, but the lack of consistent data concerning cortisol increase and/or gonadotrophin suppression pointed to the possibility of a primary defect. This was indirectly confirmed by the observation that a continuum of testicular androgen secretion potential exists from microgravity to centrifuge-derived hypergravity. Further experiments using tissue slices and suspended cells confirmed a direct inhibitory effect of microgravity upon testicular androgen production. A parallel deterioration of major physiological parameters, such as bone density, muscle mass/force, red blood cell mass, hydration and cardiopulmonary performance, has been repeatedly described during space missions, which, luckily enough, fully recover within days to weeks after landing, the time lag depending on single organ/system adaptation rates. According to the Authors of the present review, when taking together all reported changes occurring in space, a picture emerges closely resembling the so-called aging male syndrome, which is currently the object of daily screening and clinical care in their endocrine unit, so that microgravity may become a tool for better understanding subtle mechanisms of testicular senescence.


Assuntos
Envelhecimento/fisiologia , Hipófise/fisiologia , Testículo/fisiologia , Testosterona/deficiência , Ausência de Peso/efeitos adversos , Animais , Feminino , Humanos , Masculino , Ratos , Testículo/citologia , Testosterona/sangue , Testosterona/urina
17.
J Cell Biol ; 154(1): 187-96, 2001 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-11449000

RESUMO

The NgCAM-related cell adhesion molecule (NrCAM) is an immunoglobulin superfamily member of the L1 subgroup that interacts intracellularly with ankyrins. We reveal that the absence of NrCAM causes the formation of mature cataracts in the mouse, whereas significant pathfinding errors of commissural axons at the midline of the spinal cord or of proprioceptive axon collaterals are not detected. Cataracts, the most common cause of visual impairment, are generated in NrCAM-deficient mice by a disorganization of lens fibers, followed by cellular disintegration and accumulation of cellular debris. The disorganization of fiber cells becomes histologically distinct during late embryonic development and includes abnormalities of the cytoskeleton and of connexin50-containing gap junctions. Furthermore, analysis of lenses of ankyrin-B mutant mice also reveals a disorganization of lens fibers at postnatal day 1, indistinguishable from that generated by the absence of NrCAM, indicating that NrCAM and ankyrin-B are required to maintain contact between lens fiber cells. Also, these studies provide genetic evidence of an interaction between NrCAM and ankyrin-B.


Assuntos
Anquirinas/fisiologia , Catarata/metabolismo , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/fisiologia , Cristalino/metabolismo , Actinas/metabolismo , Fatores Etários , Animais , Anquirinas/genética , Axônios/metabolismo , Catarata/patologia , Adesão Celular , Conexinas , Proteínas do Olho/metabolismo , Feminino , Junções Comunicantes , Marcação de Genes , Genótipo , Homozigoto , Immunoblotting , Cristalino/patologia , Masculino , Camundongos , Camundongos Knockout , Modelos Biológicos , Modelos Genéticos , Neurônios/metabolismo , Ratos , Medula Espinal/metabolismo , Distribuição Tecidual
18.
J Clin Endocrinol Metab ; 85(5): 1954-62, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10843181

RESUMO

Aging is associated with changes in plasma levels of several hormones. There are conflicting reports on whether circulating leptin levels change during aging, the possible explanation for which is that alterations in adiposity and body mass index (BMI) also occur. In this study we measured plasma leptin and other hormonal parameters known to influence leptin in 150 men and 320 women of a wide age (18-77 yr) and BMI (18.5-61.1 kg/m2) range. Subjects of each gender were separated into 2 groups of similar BMI, i.e. nonobese (BMI, <30) and obese (BMI, >30), and treated separately. Statistical analysis was performed, treating each group of subjects as a whole population or divided into age groups (<30, 30-50, and >50 yr). BMI-adjusted leptin levels were progressively lower with increasing age in women, with a consistent fall after menopause (-21%; P < 0.001); in men, leptin levels also tended to be lower in subjects more than 50 yr of age, but the reduction was not significant. Multiple linear regression analysis, performed on subjects treated either as a whole population or divided into obese and nonobese, showed that in both genders BMI and age were independent contributors of leptin levels, and there was an inverse relationship between leptin and age in both obese (standardized coefficient beta = -0.25 in women and -0.23 in men; P < 0.01) and nonobese (-0.22 in women and -0.20 in men; P < 0.05) subjects. The correlation of leptin and age with plasma levels of sex and thyroid hormones, GH, insulin-like growth factor I, PRL, and insulin was also evaluated. The variables that correlated with leptin were included in a multiple regression model that included BMI and age. Testosterone in men (-0.43 in nonobese and -0.19 in obese; P < 0.05) and estradiol in women (0.22 in nonobese and 0.24 in obese; P < 0.05) were important contributors to leptin levels; also, dehydroepiandrosterone sulfate in obese women (-0.16) and sex hormone-binding globulin in obese subjects of both genders (0.15 in women and 0.19 in men) were significant determinants in the model. However, none of the hormonal parameters abolished the negative correlation between leptin and age or the gender difference in leptin levels. In conclusion, our data show that in adult humans of different body weight, serum leptin gradually declines during aging; leptin reduction is higher in women than in men, but it is independent from BMI and other age-related endocrine changes.


Assuntos
Envelhecimento/fisiologia , Peso Corporal , Hormônios/sangue , Leptina/sangue , Adolescente , Adulto , Idoso , Envelhecimento/sangue , Androgênios/sangue , Glicemia/metabolismo , Estudos Transversais , Estradiol/sangue , Feminino , Humanos , Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , Masculino , Pessoa de Meia-Idade , Prolactina/sangue , Valores de Referência , Caracteres Sexuais , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangue
19.
Cell Biol Int ; 24(1): 51-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10826772

RESUMO

A high anti-leishmanial activity was observed in an aqueous extract from the marine sponge Pachymatisma johnstonii, Bowerbank 1842 (Demospongiae, Geodiidae). Pachymatismin, a glycoprotein, was purified and shown to be a cytotoxic agent, which acts on promastigote and clinical-like amastigote stages with IC50 about 1 microg protein/ml and induces changes in the cell shape, phospholipase A2 activity and invasion capacity of the parasite. We believe pachymatismin is the first reported substance from a marine organism with anti-leishmanial activity.


Assuntos
Antiprotozoários/farmacologia , Glicoproteínas/farmacologia , Leishmania/efeitos dos fármacos , Poríferos/química , Animais , Antiprotozoários/isolamento & purificação , Glicoproteínas/isolamento & purificação , Técnicas In Vitro , Concentração Inibidora 50 , Peptídeos e Proteínas de Sinalização Intercelular , Leishmania/citologia , Leishmania/crescimento & desenvolvimento , Macrófagos Peritoneais/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Varredura , Fosfolipases A/metabolismo , Fosfolipases A2
20.
Cancer Chemother Pharmacol ; 45(2): 120-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10663626

RESUMO

Pachymatismin is a new cytostatic factor extracted from the marine sponge Pachymatisma johnstonii Bowerbank. To investigate the mechanism of action of pachymatismin, we studied its effects on two human prostate cell lines (DU145 and E4) of tumor origin. Immunocytochemistry demonstrated that the drug caused depolymerization of microtubules in DU145 cells, this effect being similar to that of estramustine, known to be a microtubule-depolymerizing agent. E4 cells, described to be resistant to the microtubule-depolymerizing agent estramustine, were also found resistant to pachymatismin. Pachymatismin at the same dose that destroys microtubule organization in DU145 cells is not able to induce microtubule depolymerization in E4 cells. Compared to the estramustine- and pachymatismin-sensitive DU145 cells, E4 cells revealed an increase of betaI+II, betaIII, betaIV isotypes as well as post-translational modifications of tubulin, such as polyglutamylation and acetylation. In addition, the level of tau protein was also enhanced in E4 cells compared to DU145 cells. The effects of pachymatismin were tested in vitro using calf brain microtubules. It was shown that the drug lowers the capacity of microtubules to reassemble in vitro. Interestingly, pachymatismin has been found to inhibit microtubule assembly less efficiently when the ratio of tau to tubulin is increased. Taken together, pachymastismin has been shown to induce in vivo microtubule depolymerization following binding to microtubule proteins. Changes in microtubule components such as tubulin isoforms or tau may be involved in a decrease of sensitivity to pachymatismin.


Assuntos
Antineoplásicos/farmacologia , Glicoproteínas/farmacologia , Microtúbulos/ultraestrutura , Neoplasias da Próstata/patologia , Animais , Encéfalo/citologia , Bovinos , Relação Dose-Resposta a Droga , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Proteínas Associadas aos Microtúbulos/farmacologia , Células Tumorais Cultivadas/fisiologia
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