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  • Electronic Resource  (3)
  • 1990-1994  (3)
  • 1992  (3)
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  • Electronic Resource  (3)
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  • 1990-1994  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neuroendocrinology 4 (1992), S. 0 
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Oestradiol-17ß, in its positive feedback mode, as well as stimulating the release of luteinizing hormone-releasing hormone. (LHRH), also stimulates LHRH mRNA synthesis in medial preoptic neurons. Our aim was to determine whether the action of oestradiol might be mediated in part by inhibiting arcuate proopiomelanocortin (POMC) neurons which terminate on LHRH neurons. Female rats were ovariectomized at about 1000 h of dioestrus, given a subcutaneous injection of oil or oestradiol benzoate and killed at 1600 h the same day (presumptive dioestrus), presumptive pro-oestrus and oestrus and at 1000 h of presumptive pro-oestrus. In situ hybridization of brain sections was carried out with a [35S]UTP-labelled riboprobe containing 538 bases of a cDNA identical to exon 3 of the POMC gene, which includes the ß-endorphin coding domain. The amount of POMC mRNA in cells of the anterior arcuate nucleus, as assessed by grain counts, was significantly decreased in oestradiol benzoate- compared with oil-treated animals at 1600 h of pro-oestrus, but at none of the other times studied. This finding, together with other data, suggests that the positive feedback stimulation of LHRH mRNA synthesis by oestradiol-17ß may be due, in part, to the disinhibition of LHRH neurons consequent on inhibition of POMC mRNA biosynthesis in arcuate neurons.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Advances in contraception 8 (1992), S. 313-317 
    ISSN: 1573-7195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé De récentes études ont permis d'observer et de mettre en évidence la forte incidence d'hypothyroïdie occulte chez les femmes ménorragiques. Afin de vérifier cette assertion, nous avons évalué l'activité fonctionnelle de la thyroïde chez les femmes portant un dispositif intra-utérin (DIU) et présentant un flux menstruel accru. Le groupe étudié comprenait 40 de ces femmes, âgées de 26 à 46 ans, souffrant de métrorragie. Le groupe témoin était composé de 38 femmes portant elles aussi un DIU, âgées de 24 à 44 ans, dont le flux menstruel n'avait pas augmenté de façon significative. La ménorragie a été définie comme étant un écoulement vaginal de sang anormalement abondant, durant 6 jours ou plus et/ou contenant une quantité significative de caillots. On a mesuré les niveaux de thyroxine libre (FT) et de thyréostimuline hypophysaire (TSH). Les niveaux de FT, identiques dans les deux groupes, se situaient dans la gamme normale de 1,31±0,28 ng/dl. Les taux de TSH étaient significativement plus élevés chez le groupe étudié que chez le groupe témoin, bien que restant dans la gamme normale, de 2,75±2,06 par comparaison avec 1,45±0,45 μU/ml, soitp〈0,01. Les 10 femmes dont les niveaux de TSH étaient les plus élevés ont été soumises au test à la thyréotrophine (TRH). Tous les résultats de ces tests étaient compatibles avec la présence d'une hypothyroïdie occulte. Un traitement à la thyroxine libre prescrit à ces femmes a entraîné une amélioration significative de leur flux menstruel dans les 3 mois suivant le début du traitement. Nous en avons conclu que toute femme portant un DIU et souffrant de ménorragie peut présenter une hypothyroïdie occulte. Si les niveaux de FT et de TSH entrent dans les limites normales, il y aurait lieu de procéder à un test à la TRH pour établir un diagnostic définitif.
    Abstract: Resumen En estudios realizados recientemente se observó y destacó la gran incidencia de hipotiroidismo oculto en mujeres menorrágicas. A fin de verificar esta aseveración, evaluamos la actividad funcional de la tiroides en mujeres que tenían colocado un dispositivo intrauterino (DIU) y que presentaban un flujo menstrual aumentado. El grupo estudiado comprendía 40 mujeres, de 26 a 46 años, que tenían DIU y sufrían metrorragias. El grupo testigo constaba de 38 mujeres asimismo con DIU, de 24 a 44 años, cuyo flujo menstrual no había aumentado de modo significativo. La menorragia se definió como flujo vaginal de sangre excesivo, de 6 o más de duración y/o con catidades significativas de coágulos. Se midieron los niveles de tiroxina libre (FT) y de la hormona estimulante de la tiroides (TSH). Los niveles de FT eran idénticos en los dos grupos y dentro de la gama normal de 1,31±0,28 ng/dl. Las proporciones de TSH eran significativamente superiores en el grupo de estudio que en el grupo testigo, si bien continuaban comprendidas dentro de la gama normal de 2,75±2,06 en comparación con 1,45±0,45 μU/ml,p〈0,01. La prueba de hormona de descarga de tirotropina (TRH) se realizó en las 10 mujeres con los niveles más altos de TSH. Todos los resultados de estas pruebas eran compatibles con hipotiroidismo oculto. Esas mujeres fueron tratadas conl-tiroxina y su flujo menstrual mejoró significativamente dentro de los tres meses de tratamiento. Llegamos a la conclusión de que cualquier mujer con DIU que sufre menorragia puede tener hipotiroidismo oculto. Si los niveles de FT y TSH están dentro de los límites normales, debe realizarse una prueba de TRH para tener un diagnóstico definitivo.
    Notes: Abstract A high incidence of occult hypothyroidism in menorrhagic women has been reported and emphasized in recent studies. In order to verify this statement, we have evaluated the functional status of the thyroid gland in intrauterine device (IUD) wearers suffering from increased menstrual bleeding. The study group consisted of 40 IUD-wearing women, aged 36–46 years, suffering from metrorrhagia. The control group consisted of 38 IUD-fitted women, 22–44 years old, in whom menstrual bleeding was not significantly increased. Menorrhagia was defined as excessive vaginal bleeding lasting for 6 days or more, and/or containing a significant amount of blood clots. Free thyroxine (FT) and thyroid-stimulating hormone (TSH) levels were assessed. FT levels were identical in both groups and within the normal range (1.31±0.28 ng/dl). TSH levels were significantly higher in the study group than in the controls, although they remained within the normal range (2.75±2.06 vs. 1.45±0.45 μU/ml,p〈0.01). A thyrotropin-releasing hormone (TRH) test was performed in 10 women having the highest TSH levels. All the results of TRH tests were consistent with occult hypothyroidism. These women were treated withl-thyroxine and all had a significant improvement in their bleeding within 3 months of treatment. We concluded that any IUD-wearing woman suffering from menorrhagia may have occult hypothyroidism. Should FT and TSH be within normal limits, a TRH test should be performed as the fefinitive diagnostic test. A frequent side-effect of intrauterine contraception is menometrorrhagia. The intrauterine device (IUD) has to be removed in 5–15% of cases to prevent iron deficiency anemia [1–3].
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 18 (1992), S. 1633-1640 
    ISSN: 1573-1561
    Keywords: Apis mellifera ; honeybee ; Hymenoptera ; Apidae ; queen ; fecal ; pheromones ; esters ; kin recognition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Previous work has shown that queen honeybees,Apis mellifera, produce waxy esters composed of 8–14 carbon acids and 6–14 carbon alcohols in their feces. We tested these esters for effects on nestmate recognition; 11 of the 12 esters tested significantly modified the recognition characteristics of worker honeybees. Pairwise tests showed that workers can discriminate between at least some pairs of queen esters and that workers can discriminate between a queen ester and hexadecane (another known nestmate recognition cue). These results suggest that a queen may use the esters to enable workers to recognize her or to scent-mark her colony.
    Type of Medium: Electronic Resource
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