With the advent of IVF technology, the terms normal and abnormal oocytes have been defined and one type of abnormal oocyte is the “giant oocyte”. Giant oocytes are defined to have a 30% larger diameter and twice the volume of normal oocytes[1,2]. Giant oocyte is a rarery observed phenomenon among humans and embryos may develop from these oocytes [2,3].The first hypothesis for the mechanism of t...

Electrophysiological and morphological methods were used to study connexin50 (Cx50) expressed in Xenopus laevis oocytes. Oocytes expressing Cx50 exhibited a new population of intramembrane particles (9.0 nm in diameter) in the plasma membrane. The particles represented hemichannels (connexin hexamers) because (a) their cross-sectional area could accommodate 24 +/- 3 helices, (b) when their dens...

in vitro maturation (ivm) is a method that immature oocytes in antral follicles are extracted and matured in laboratry conditions. this review has attempted to provide the current knowledge and recent findings in in vitro maturation of oocytes and highlights the most important factors involved in this process. the review is based on literature reports and the author’s experience. in ivm cycles,...

Three experiments were conducted to evaluate factors affecting number of surface ovarian follicles and oocytes yield and quality in buffalo. In Experiment 1, ovaries (n = 126) were collected in pairs from slaughtered anoestrus, early pregnant and cyclic buffaloes. Ovarian follicles (1-3, 4-9 and > or = 10 mm diameter) were counted, aspirated and oocytes were recovered and evaluated. In Experime...

Background: In vitro maturation and fertilization are techniques to increase efficiency of mammals reproduction. However, in vitro culture conditions exert an imbalance between oxidants and antioxidants which may reduce live birth and pregnancy rates when compare to in vivo conditions. Materials and Methods: The present study was conducted as a part of the ovine IVF program organized by Univers...

Mitochondria are responsible for the production of ATP, which drives cellular metabolic and biosynthetic processes. This is the first study to quantify the mtDNA copy number across all stages of oogenesis in a large monovulatory species, it includes assessment of the activity of mitochondria in germinal vesicle (GV) and metaphase II (MII) oocytes through JC1 staining. Primordial to early antral...

The development of the mitochondrial mass of the previtellogenic oocytes of Xenopus laevis has been analysed by a morphometric method and it has been correlated with the growth of the occyte itself. The study which was performed with oocytes from females of very different ages shows that the relative size of the mitochondrial mass in the smallest oocytes decreases gradually with the age of the ...

Nuclei of frog oocytes were isolated, fixed in OsO(4) or KMnO(4), and washed. Nuclear envelopes were then dissected off, placed on grids, and air-dried for electron microscopy. Envelopes from immature oocytes at the stage of beginning yolk deposition were compared with those from mature oocytes. Envelopes from the immature stage had "pores" whose annuli contained more material and showed centra...

25 In the physiological condition, mammalian oocytes and embryos appears to be stimulated not only chemically but also mechanically, such as compression, shear stress and/or friction force in the follicle and female reproductive tract. The present study was undertaken to examine the effects of kinetic culture with a tilting device in chemically defined media during in vitro maturation (IVM) of ...

BACKGROUND The negative impact of rising progesterone levels on pregnancy rates is well known, but data on mature oocyte yield are conflicting. We examined whether delaying the oocyte maturation trigger in IVF/ICSI affected the number of mature oocytes and investigated the potential influence of serum progesterone levels in this process. METHODS Between January 31, 2011, and December 31, 2011...