Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Biol Reprod ; 106(1): 95-107, 2022 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-34672344

RESUMO

Key biomolecular processes, which regulate primordial ovarian follicle dormancy and early folliculogenesis in mammalian ovaries, are not fully understood. The domestic cat is a useful model to study ovarian folliculogenesis and is the most relevant for developing in vitro growth methods to be implemented in wild felid conservation breeding programs. Previously, RNA-sequencing of primordial (PrF), primary (PF), and secondary follicle (SF) samples from domestic cat implicated ovarian steroidogenesis and steroid reception during follicle development. Here, we aimed to identify which sex steroid biosynthesis and metabolism enzymes, gonadotropin receptors, and sex steroid receptors are present and may be potential regulators. Differential gene expression, functional annotation, and enrichment analyses were employed and protein localization was studied too. Gene transcripts for PGR, PGRMC1, AR (steroid receptors), CYP11A1, CYP17A1, HSD17B1 and HSD17B17 (steroidogenic enzymes), and STS (steroid metabolizing enzyme) were significantly differentially expressed (Q values of ≤0.05). Differential gene expression increased in all transcripts during follicle transitions apart from AR which decreased by the secondary stage. Immunohistochemistry localized FSHR and LHCGR to oocytes at each stage. PGRMC1 immunostaining was strongest in granulosa cells, whereas AR was strongest in oocytes throughout each stage. Protein signals for steroidogenic enzymes were only detectable in SFs. Products of these significantly differentially expressed genes may regulate domestic cat preantral folliculogenesis. In vitro growth could be optimized as all early follicles express gonadotropin and steroid receptors meaning hormone interaction and response may be possible. Protein expression analyses of early SFs supported its potential for producing sex steroids.


Assuntos
Gatos/fisiologia , Hormônios Esteroides Gonadais/metabolismo , Gonadotropinas/metabolismo , Folículo Ovariano/fisiologia , Transdução de Sinais/fisiologia , 17-Hidroxiesteroide Desidrogenases/análise , 17-Hidroxiesteroide Desidrogenases/genética , Animais , Sistema Enzimático do Citocromo P-450/análise , Sistema Enzimático do Citocromo P-450/genética , Estradiol Desidrogenases , Feminino , Regulação da Expressão Gênica , Hormônios Esteroides Gonadais/biossíntese , Folículo Ovariano/enzimologia , Receptores da Gonadotropina/análise , Receptores da Gonadotropina/genética , Receptores da Gonadotropina/fisiologia , Receptores de Esteroides/análise , Receptores de Esteroides/genética , Receptores de Esteroides/fisiologia , Análise de Sequência de RNA
2.
Fungal Syst Evol ; 6: 233-242, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32904151

RESUMO

To resolve the polyphyletic nature of Solenopeziaceae as it was originally circumscribed, we establish a new family Tricladiaceae for those genera originally placed in Solenopeziaceae that have aquatic hyphomycete-like asexual morphs and/or a sexual morph with glabrous apothecia. These include Cudoniella, Geniculospora, Graddonia, Halenospora, Mycofalcella, Spirosphaera, and Tricladium. Solenopeziaceae is confined to the genera Lasiobelonium, Solenopezia, Trichopeziza, and Trichopezizella, all of which have a sexual morph having apothecia with smooth-walled hairs. This taxonomy is supported by a multi-gene analysis using up to 15 genes, with a few of the taxa placed on the basis of a separate ITS phylogeny. Tricladiaceae forms a monophyletic clade with a basal sister relationship to Pleuroascaceae plus Helotiaceae; Solenopeziaceae forms a monophyletic clade with a basal sister relationship to Lachnaceae.

3.
Med Eng Phys ; 74: 89-98, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31570217

RESUMO

Increasing impedance during freezing might be a valuable marker for guiding cardiac cryo-ablation. We provide model based insights on how decreasing temperature below the freezing point of tissue relates to the percentage of frozen water. Furthermore, we provide experimental data for comparing this percentage with the increase in impedance. Measurements were performed on a bovine tissue sample at frequencies between 5 and 80 kHz. Slow cooling and heating rates were applied to minimize temperature gradients in the myocardial sample and to allow accurate assessment of the freezing point. Computer simulation was applied to link impedance with temperature dependent conductivities. The osmotic virial equation was used to estimate the percentage of frozen water. Measurements identified the freezing point at -0.6 ∘C. At -5 ∘C, impedance rose by more than a factor of ten compared to that at the freezing point and the percentage of frozen water was estimated as being 89%. At -49 ∘C impedance had increased by up to three orders of magnitude and ice formation was most pronounced in the extracellular space. Progressive ice formation in tissue is reflected by a large increase in impedance, and impedance increases monotonically with the percentage of frozen water. Its analysis allows for experimental assessment of factors relevant to cell death. Solid ice contributes to the rupture of the micro-vasculature, while phase shifts reflect concentration differences between extra- and intracellular space driving osmotic water transfer across cell membranes.


Assuntos
Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Criocirurgia/efeitos adversos , Condutividade Elétrica , Congelamento/efeitos adversos , Miocárdio/citologia , Animais , Bovinos , Impedância Elétrica , Eletrodos , Teste de Materiais
4.
AJNR Am J Neuroradiol ; 39(3): 552-557, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29301780

RESUMO

BACKGROUND AND PURPOSE: Accurate tumor grading is essential for treatment planning of pediatric brain tumors. We hypothesized that multiparametric analyses of a combination of permeability metrics and ADC histogram metrics would differentiate high- and low-grade tumors with high accuracy. MATERIALS AND METHODS: DTI and dynamic contrast-enhanced MR imaging using T1-mapping with flip angles of 2°, 5°, 10°, and 15°, followed by a 0.1-mmol/kg body weight gadolinium-based bolus was performed on all patients in addition to standard MR imaging. Permeability data were processed and transfer constant from the blood plasma into the extracellular extravascular space, rate constant from the extracellular extravascular space back into blood plasma, extravascular extracellular volume fraction, and fractional blood plasma volume were calculated from 3D tumor volumes. Apparent diffusion coefficient histogram metrics were calculated for 3 separate tumor volumes derived from T2-FLAIR sequences, T1 contrast-enhanced sequences, and permeability maps, respectively. RESULTS: Results from 41 patients (0.3-16.76 years of age; mean, 6.22 years) with newly diagnosed contrast-enhancing brain tumors (16 low-grade; 25 high-grade) were included in the institutional review board-approved retrospective analysis. Wilcoxon tests showed a higher transfer constant from blood plasma into extracellular extravascular space and rate constant from extracellular extravascular space back into blood plasma, and lower extracellular extravascular volume fraction (P < .001) in high-grade tumors. The mean ADCs of FLAIR and enhancing tumor volumes were significantly lower in high-grade tumors (P < .001). ROC analysis showed that a combination of extravascular volume fraction and mean ADC of FLAIR volume differentiated high- and low-grade tumors with high accuracy (area under receiver operating characteristic curve = 0.918). CONCLUSIONS: ADC histogram metrics combined with permeability metrics differentiate low- and high-grade pediatric brain tumors with high accuracy.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Imageamento por Ressonância Magnética/métodos , Gradação de Tumores/métodos , Adolescente , Neoplasias Encefálicas/classificação , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Permeabilidade , Curva ROC , Estudos Retrospectivos
5.
Stud Mycol ; 68: 237-47, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21523197

RESUMO

Two new pathogens, Guignardia korthalsellae and Rosenscheldiella korthalsellae, are described from New Zealand's pygmy mistletoes (Korthalsella, Viscaceae). Both form ascomata on living phylloclades with minimal disruption of the tissue. Fungal hyphae within the phylloclade are primarily intercellular. Guignardia korthalsellae disrupts a limited number of epidermal cells immediately around the erumpent ascoma, while the ascomata of Rosenscheldiellakorthalsellae develop externally on small patches of stromatic tissue that form above stomatal cavities. Rosenscheldiella is applied in a purely morphological sense. LSU sequences show that R. korthalsellae as well as another New Zealand species, Rosenscheldiella brachyglottidis, are members of the Mycosphaerellaceaesensu stricto. Genetically, Rosenscheldiella, in the sense we are using it, is polyphyletic; LSU and ITS sequences place the two New Zealand species in different clades within the Mycosphaerellaceae. Rosenscheldiella is retained for these fungi until generic relationships within the family are resolved. Whether or not the type species of Rosenscheldiella, R. styracis, is also a member of the Mycosphaerellaceae is not known, but it has a similar morphology and relationship to its host as the two New Zealand species.

6.
Mycologia ; 103(1): 57-74, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20943536

RESUMO

Rhytismatales (Leotiomycetes, Pezizomycotina, Ascomycota) are an order of mostly plant-associated ascomycetes with a global distribution. Well known taxa include the Rhytisma tar spots on Acer spp. and several needle-cast pathogens in genera Lophodermium and Meloderma. Critical studies are lacking at all taxonomic ranks from order to species, and in particular the genus taxonomy in the order has been criticized for being unnatural. We used nuclear LSU and mitochondrial SSU sequences in Bayesian phylogenetic analyses to define a core clade of Rhytismatales sensu stricto. Some of the genera traditionally placed within the Rhytismatales, Ascodichaena, Marthamyces, Mellitiosporium, Potebniamyces, Propolis and Pseudophacidium, are shown to be phylogenetically distinct, all related to various other taxa at present placed in the polyphyletic Helotiales. Within the core clade only Cudonia, Spathularia and Terriera are supported as monophyletic. The large genera Coccomyces, Hypoderma and Lophodermium all are polyphyletic as are a few smaller genera. The traditionally used characters of ascoma and spore shape are shown to be unreliable for the delimitation of monophyletic genera but in some cases can be useful when combined with other characters. In this study we provide 72 new nrLSU and 64 new mtSSU sequences. Together with publicly available sequences data for 103 specimens representing 91 species of Rhytismatales are now available. Despite this taxon sampling intensity is still too low to propose an alternative generic taxonomy.


Assuntos
Ascomicetos/genética , Ascomicetos/classificação , Ascomicetos/ultraestrutura , Sequência de Bases , DNA Fúngico/química , DNA Fúngico/genética , DNA Mitocondrial/química , DNA Mitocondrial/genética , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Alinhamento de Sequência
7.
Tob Control ; 11 Suppl 2: ii59-63, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12034984

RESUMO

OBJECTIVE: To determine the effects of health warning characteristics in smokeless tobacco magazine print ads on warning recall, and the implications for current US Federal regulations. DESIGN: Subjects examined two distracter ads and one of nine randomly assigned smokeless tobacco ads varying in health warning presence, size (8 to 18 point font), and contrast (low versus high)-including no health warning. They were then interviewed about ad content using recall and recognition questions. SUBJECTS: A convenience sample of 895 English speaking males aged 16-24 years old who were intercepted at seven shopping malls throughout Massachusetts during May 2000. MAIN OUTCOME MEASURES: Proven aided recall, or recall of a health warning and correct recognition of the warning message among distracters, and false recall. RESULTS: Controlling for covariates such as education, employment/student status, and Hispanic background, proven aided recall increased significantly with font size; doubling size from 10 to 20 point font would increase recall from 63% to 76%. Although not statistically significant, recall was somewhat better for high contrast warnings. Ten per cent of the sample mistakenly recalled the warning where none existed. CONCLUSIONS: As demonstrated by substantially greater recall among ads that included health warnings over ads that had none, health warnings retained their value to consumers despite years of exposure (that can produce false recall). Larger health warnings would enhance recall, and the proposed model can be used to estimate potential recall that affects communication, perceived health risk, and behaviour modification.


Assuntos
Publicidade , Comportamentos Relacionados com a Saúde , Rememoração Mental , Tabaco sem Fumaça , Adolescente , Adulto , Humanos , Masculino , Massachusetts , Abandono do Uso de Tabaco
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA