RESUMEN
Bacteriorhodopsin has been reconstituted into lipid vesicles with dipalmitoyl and dimyristoyl phosphatidylcholine. Circular dichroism (CD) measurements show that the proteins are in a monomeric state above the main lipid phase transition temperature (Tc), 41 and 23 degrees C for dipalmitoyl and dimyristoyl phosphatidylcholine, respectively. Below Tc, the CD spectrum is the same as that found for the purple membrane. The latter result implies that the orientation of the chromophore at these temperatures is most likely the same as in the purple membrane (70 degrees +/- 5 degrees from the normal to the membrane plane). Transient dichroism measurements show that below Tc the proteins are immobile, while above this temperature protein rotation around an axis normal to the plane of the membrane is occurring. In addition, from the data the angle of the chromophore for the rotating proteins with respect to the rotational diffusion axis can be calculated. This angle is found to be 30 degrees +/- 3 degrees and 29 degrees +/- 4 degrees in dimyristoyl phosphatidylcholine and dipalmitoyl phosphatidylcholine, respectively. This is considerably smaller than the value of 70 degrees +/- 5 degrees for the natural biomembrane. A reversible reorientation of the chromophore above and below the respective main Tc transition temperature could explain the change of angle observed provided that all the molecules rotate above Tc.
Asunto(s)
Bacteriorodopsinas , Carotenoides , Liposomas , Dicroismo Circular , Halobacterium/metabolismo , Fosfatidilcolinas , Fotoquímica , Conformación Proteica , Surfactantes Pulmonares , TemperaturaRESUMEN
The authors, on the basis of broad and endocrinological studies and of histological investigation of the ovaries, performed in 21 women, described an uniform disease picture which allowes to delimit ovarian hypoplastic syndrome out of a group of patients with ovarial insufficiency. This syndrome is characterized by primary or secondary amenorrhoea, normal height, weak development of secondary sexfeatures, and by small ovaries which have the oval or roller, more seldom ball-like or streaking form. The histological picture of the ovaries consist of fibrous stroma without generative elements or with a small number of primary follicles, but sometimes also with single growing Graaf's follicle. The excretion of estrogens is very low and in the case of gonadotrophins it increases.
Asunto(s)
Enfermedades del Ovario/congénito , Ovario/crecimiento & desarrollo , Adulto , Estrógenos/metabolismo , Femenino , Gonadotropinas/metabolismo , Humanos , Infertilidad Femenina/etiología , Infertilidad Femenina/metabolismo , Infertilidad Femenina/patología , Enfermedades del Ovario/complicaciones , Enfermedades del Ovario/metabolismo , Enfermedades del Ovario/patología , Ovario/patología , SíndromeAsunto(s)
Laparoscopía , Enfermedades del Ovario/diagnóstico , Adolescente , Adulto , Biopsia , Femenino , Humanos , Ovario/patologíaAsunto(s)
Enfermedades del Ovario/patología , Ovario/patología , Adolescente , Adulto , Amenorrea/patología , Femenino , Humanos , SíndromeRESUMEN
PIP: Effects of chlormadinone acetate on the ovary were studied in 20 female Wistar rats. Chlormadinone was started on the 1st day of diestrus and given for 20 days; animals were killed 24 hours after the last administration. Examination of ovary sections revealed hyperplastic interstitial gland, a decreased number of corpora lutea and an increased number of atretic follicules. Histochemical studies indicated increased interstitial gland activity and full activity of atretic follicules.^ieng