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1.
Dis Aquat Organ ; 141: 47-52, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32940250

RESUMO

Reproduction of Trachurus picturatus off the western Portuguese coast was studied over 1 yr. During histological analyses, the presence of Kudoa sp. was detected in advanced vitellogenic oocytes. Kudoa infections are known to cause economic loss through the induction of post-mortem liquefaction of fish muscles, but ovarian infection as reported in this study will seriously affect the reproductive potential of the species and thus impact fisheries productivity. Only females showed gonad infection which led to total degradation of advanced vitellogenic oocytes. No macroscopic, somatic or condition indices revealed differences between infected and uninfected females, rendering this infection event a concealed suppression of reproduction.


Assuntos
Doenças dos Peixes , Infecções/veterinária , Myxozoa , Perciformes , Animais , Feminino , Ovário , Doenças Parasitárias em Animais
2.
J Fish Biol ; 90(5): 2157-2169, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28321875

RESUMO

Two hundred and seven individuals (103 females and 104 males) of bluemouth Helicolenus dactylopterus (Scorpaeniformes, Sebastidae), a commercially important deep-water species with an unusual reproductive strategy, from the eastern Atlantic Ocean ranging from 13·9 to 37·5 cm total length (LT ) were analysed from September 2011 to October 2012. The analysis included gonad maturity phases and blood-plasma levels of oestradiol-17ß (E2 ), 11-ketotestosterone (11-KT) and 17,20ß-dihydroxypregn-4-en-3-one (17,20ß-P). Results confirmed the existence of an annual reproductive cycle with asynchrony between females and males and a spawning season from January to May. A pronounced peak in 17,20ß-P in October for both sexes was associated with possible mating behaviour and recent copula. Levels of E2 increased preceding the elevation of the gonado-somatic index during ovarian growth and were lower during regression and regeneration. The frequency distribution of oocyte-embryonic stages and variation of hormone levels suggest the existence of daily rhythms. Fertilization was detected between 2000-0000 and 0800-1200 h and spawning took place throughout the day peaking between 2000 and 0000 h. The cyclic pattern of sex steroids and ovarian recruitment provides a new insight into the reproductive strategy of this species.


Assuntos
Hormônios Esteroides Gonadais/fisiologia , Perciformes/fisiologia , Animais , Oceano Atlântico , Feminino , Hormônios Esteroides Gonadais/sangue , Masculino , Oócitos/crescimento & desenvolvimento , Reprodução/fisiologia , Estações do Ano
3.
Appl Radiat Isot ; 66(4): 421-34, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18222090

RESUMO

Within the EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) project, the gamma-ray spectra produced in a series of materials by 14-MeV tagged-neutron beams have been collected in the inspection portal equipped with large volume NaI(Tl) detectors, in order to build a database of signatures for various elements: C, N, O, Na, Al, Si, Cl, K, Ca, Cr, Fe, Ni, Cu, Zn, Pb. The measured spectra have been compared with prediction from Monte Carlo simulations to verify the consistency of the relevant nuclear data inputs. This library of measured 14-MeV neutron-induced gamma-ray spectra is currently used in a data processing algorithm to unfold the energy spectra of the transported goods into elementary contributions, thus allowing material identification.

4.
Eur J Clin Nutr ; 65(9): 986-93, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21731037

RESUMO

Under normal circumstances, vitamin D is mainly obtained from skin through the action of ultraviolet B irradiation on 7-dehydrocholesterol. It is further metabolized to 25-hydroxyvitamin D (25OHD), the major circulating vitamin D compound, and then to 1,25-dihydroxyvitamin D, the hormonal form. The major function of vitamin D compounds is to enhance active absorption of ingested calcium (and phosphate). This assists in building bone at younger ages and ensures that despite obligatory urinary losses, bone does not need to be resorbed to maintain blood calcium concentrations. Vitamin D compounds appear to have direct effects to improve bone and muscle function, and there is good, although not entirely consistent, evidence that supplemental vitamin D and calcium together reduce falls and fractures in older individuals. On the basis of calcium control and musculoskeletal function, target levels for 25OHD in blood are at least 50-60 nmol/l and there may be a case for higher targets of 75-80 nmol/l. There are vitamin D receptors in most nucleated cells and some evidence, although not consistent, that adequate vitamin D levels may be important in reducing the incidence of, or mortality from, some cancers and in reducing autoimmune disease. Adequate vitamin D may also allow for a normal innate immune response to pathogens, improve cardiovascular function and mortality and increase insulin responsiveness. Vitamin D levels are maintained better in the presence of adequate calcium intakes, more exercise and less obesity. Genetic variation may have an effect on vitamin D blood levels and response to treatment with vitamin D.


Assuntos
Luz Solar , Deficiência de Vitamina D/terapia , Vitamina D/sangue , Vitamina D/metabolismo , Osso e Ossos/metabolismo , Osso e Ossos/fisiologia , Cálcio da Dieta/sangue , Desidrocolesteróis/efeitos da radiação , Suplementos Nutricionais , Humanos , Fenômenos Fisiológicos Musculoesqueléticos , Pele/metabolismo , Raios Ultravioleta , Vitamina D/fisiologia , Deficiência de Vitamina D/fisiopatologia
5.
J Steroid Biochem Mol Biol ; 121(1-2): 164-8, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20399269

RESUMO

Ultraviolet (UV) irradiation causes DNA damage in skin cells, immunosuppression and photocarcinogenesis. 1alpha,25-dihydroxyvitamin D3 (1,25D) reduces UV-induced DNA damage in the form of cyclobutane pyrimidine dimers (CPD) in human keratinocytes in culture and in mouse and human skin. UV-induced immunosuppression is also reduced in mice by 1,25D, in part due to the reduction in CPD and a reduction in interleukin (IL-6. The cis-locked analog, 1alpha,25-dihydroxylumisterol3 (JN), which has almost no transactivating activity, reduces UV-induced DNA damage, apoptosis and immunosuppression with similar potency to 1,25D, consistent with a non-genomic signalling mechanism. The mechanism of the reduction in DNA damage in the form of CPD is unclear. 1,25D doubles nuclear expression of p53 compared to UV alone, which suggests that 1,25D facilitates DNA repair. Yet expression of a key DNA repair gene, XPG is not affected by 1,25D. Chemical production of CPD has been described. Incubation of keratinocytes with a nitric oxide donor, SNP, induces CPD in the dark. We previously reported that 1,25D reduced UV-induced nitrite in keratinocytes, similar to aminoguanidine, an inhibitor of nitric oxide synthase. A reduction in reactive nitrogen species has been shown to facilitate DNA repair, but in view of these findings may also reduce CPD formation via a novel mechanism.


Assuntos
Calcitriol/análogos & derivados , Calcitriol/farmacologia , Animais , Células Cultivadas , Dano ao DNA , Reparo do DNA , Ergosterol/análogos & derivados , Ergosterol/farmacologia , Guanidinas/farmacologia , Humanos , Interleucina-6/metabolismo , Queratinócitos/citologia , Queratinócitos/efeitos da radiação , Camundongos , Modelos Biológicos , Óxido Nítrico Sintase/metabolismo , Espécies Reativas de Nitrogênio , Raios Ultravioleta
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