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Ultrastructural features and meiotic spindle dynamics in human mature oocytes subjected to different cryopreservation protocols
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Fine Structural Markers of Human Oocyte Quality in Assisted Reproduction
No full textAfter completing its maturation, the human oocyte acquires very peculiar
fine structural features. In this review we describe by LM, TEM and SEM the
nuclear and cytoplasmic changes, as well as the changes in the texture of the
ZP, occurring in the human oocyte during the final stages of maturation. Oocytes
were obtained during ART cycles and destined to morphological evaluation after
the informed consent of the patients. The critical analysis of the data reviewed
leads us to emphasize that: 1. Both the completion of the maturative changes
in the preovulatory period and the absence of degenerative alterations in the
cytoplasmic microdomains of the human mature oocyte ultimately render the
female gamete competent for fertilization; 2. Several minute cellular aberrations,
detectable only by electron microscopy analysis, may occur in the human
oocyte as the consequence of the application of ART protocols (IVM and
cryopreservation, in particular) and could be responsible for ART failures, even
affecting early embryo development.
Keywords: Oocyte; Assiste
The angioarchitecture of estrous, pseudopregnant and pregnant rabbit ovary as seen by scanning electron microscopy of vascular corrosion casts
No full textOvarian angioarchitecture was studied by scanning electron microscopy of vascular
corrosion casts in estrous, pseudopregnant (stimulated with human chorionic
gonadotropin) and pregnant rabbits. In all samples, the proper ovarian branch of
the ovarian artery (ramus ovaricus) entered the ovarian hilus near the caudal
pole of the organ and ran parallel to the major axis of the hilus. The
extraovarian venous drainage was formed by several vessels emptying into a distal
large vein. The ramus ovaricus exhibited various degrees of coiling and branched
in the medulla. The coiling of the ramus ovaricus and its ramifications were
maintained in all samples. A venous meshwork and/or flat vein branches closely
enveloped the arterial coils found in the hilus and outer medulla. At this level
numerous arteriovenous contacts were demonstrated in all samples. The coiled
arteries, prior to entering the ovarian cortex, supplied several small peripheral
follicles which were drained by the hilar veins. In the cortex the coiled
arteries branched in numerous thin, straight or slightly undulated arterioles
which supplied developing estrous follicles and pseudopregnant corpora lutea. The
arterioles supplying the pregnant corpora lutea were long, large and tightly
spiraled. The venous drainage followed the modifications of the arterial supply.
These data demonstrate that ovarian cycle and pregnancy induced significant
changes in the cortical vessels, which adapted their structure to the temporary
functional needs of the recruited follicles or corpora lutea. Hilar and medullary
vessels have permanent structures that may represent morphological devices for
(a) a continuous control of the blood flow (spiral arteries) and (b) a local
recirculation of endocrine products (arteriovenous contacts) comparable to the
"countercurrent mechanism" previously shown to operate in ovaries of other
species, but not yet found in rabbit
Advances in Microanatomy of Cells and Tissues: Biophysical and Biochemical Correlates. Marcello Malpighi Series: Vol. 7. in ITALIAN JOURNAL OF ANATOMY AND EMBRYOLOGY
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Ovarian vessels in estrous, pseudopregnant and pregnant rabbits as revealed by microcorrosion casts and scanning electron microscopy
No full textInsegnamento multimediale in Anatomia. Elaborazione di un software didattico sperimentale
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