Contribution of culture media to oxidative stress and its effect on human oocytes.

The adverse effects of reactive oxygen species (ROS) on many aspects of reproduction are well documented. However, much less is known regarding the contribution of culture media to the oxidative stress of gametes during assisted reproductive techniques. This study measured the generation of ROS by culture media during IVF procedures and its effects on human oocytes. Commercially supplied culture media generated ROS at various rates, depending on the composition, whereas follicular fluid generated ROS at a much lower level. The incubation of cumulus-oocyte complexes (COC) in culture media induced marked lipid peroxidation compared with levels found in freshly retrieved COC. This plasma membrane damage, measured with the quenching of cis-parinaric acid fluorescence assay, was attenuated by supplementation of the medium with alpha-tocopherol or catalase. Moreover, there was an association between ROS production by culture medium and thiolic content consumption within the oocytes, suggesting that the intracellular reduced glutathione pool was partially depleted during in-vitro manipulation. The results show that culture medium could damage oocytes (and consequently embryo development) depending on their composition, and it is proposed that current IVF protocols could be revised in order to decrease ROS generation.

[Chondroblastoma of the proximal humerus treated with intracompartmental curettage and lyophilized bone graft. Case report and literature review]. / Condroblastoma de cabeza humeral tratado con cirugía intracompartamental y aplicación de injerto óseo liofilizado. Reporte de caso y revisión de la literatura.

UNLABELLED: Chondroblastoma is a chondroid bone tumor that frequently affects long bone epiphysis, malignancy occurs infrequently. It can alter the morphology of the joint, and appears in the second decade of life before ossification of the physes. Chondroblastoma accounts for 10% of chondroid tumors, on X-rays, it appears as a small radiolucent lesion, well defined with lytic activity and in case of aggressiveness, the lesion can extend to metaphyses. According to Enneking's classification, chondroblastoma is benign injury, with capacity of physes destruction. Prognosis improves when treatment is carried out in a timely manner. It appears clinically in the shoulder, with pain, range of motion limitation, and poor answer to NSAID's and/or physical therapy. We present a 17 year old male, with a two-year history of nightly pain of the shoulder, with poor response to NSAID's therapy, and sever ROM limitation. On plain X-rays a lytic expansive lesion involving proximal humeral epiphysis was found. We performed wide curettage aided by fluoroscopy and 60 grams of lyophilized bone graft were used. RESULTS: At 2-year follow-up full integration of bone graft, complete remission of symptoms and painless ROM of the shoulder were achieved.

Store-operated calcium entry in human oocytes and sensitivity to oxidative stress.

Calcium signaling is a cellular event that plays a key role at many steps of fertilization and early development. However, little is known regarding the contribution of extracellular Ca(2+) influx into the cell to this signaling in gametes and early embryos. To better know the significance of calcium entry on oocyte physiology, we have evaluated the mechanism of store-operated calcium entry (SOCE) in human metaphase II (MII) oocytes and its sensitivity to oxidative stress, one of the major factors implicated in the outcome of in vitro fertilization (IVF) techniques. We show that depletion of intracellular Ca(2+) stores through inhibition of sarco(endo)plasmic Ca(2+)-ATPase with thapsigargin triggers Ca(2+) entry in resting human oocytes. Ba(2+) and Mn(2+) influx was also stimulated following inhibition, and Ca(2+) entry was sensitive to pharmacological inhibition because the SOCE blocker 2-aminoethoxydiphenylborate (2-APB) reduced calcium and barium entry. These results support the conclusion that there is a plasma membrane mechanism responsible for the capacitative divalent cation entry in human oocytes. Moreover, the Ca(2+) entry mechanism described in MII oocytes was found to be highly sensitive to oxidative stress. Hydrogen peroxide, at micromolar concentrations that could mimic culture conditions in IVF, elicited an increase of [Ca(2+)](i) that was dependent on the presence of extracellular Ca(2+). This rise was preventable by 2-APB, indicating that it was mainly due to the enhanced influx through store-operated calcium channels. In sum, our results demonstrate the occurrence of SOCE in human MII oocytes and the modification of this pathway due to oxidative stress, with possible consequences in IVF.