Infertility caused by ovarian failure is a characteristic feature in Turner's syndrome. Spontaneous pregnancies are seen in 2-5% of these women, and up to 30% have at least some pubertal development, indicating the presence of follicles in their ovaries in adolescence. It has not been clear at which age the follicles disappear. We analyzed the numbers and densities of follicles in ovarian cortical tissue from nine adolescent girls with Turner's syndrome who came to our clinics after having been informed about the study, with an aim to preserve ovarian tissue for possible infertility treatment later in life. A quarter to one whole ovary was laparoscopically removed for the procedure. Follicles were seen in the biopsy tissue in eight of nine subjects from whom ovarian tissue was laparoscopically obtained, the highest numbers being seen in the youngest girls and in those with mosaicism. In one 17-yr-old girl, no ovarian tissue was found. Follicle density was correlated with serum levels of FSH; individuals with the lowest FSH levels had the highest follicle density. One to 190 follicles were counted in the approximately 0.1-2.0 mm(3) of tissue analyzed, giving a density of 1.5-499 follicles/mm(3) of ovarian cortical tissue. Girls up to the age of 17 had primordial follicles in their ovaries. Three girls, two aged 15 yr and one aged 19, had only secondary follicles, with many being atretic. Our finding that adolescent girls with Turner's syndrome still have follicles in their ovarian cortical tissue raises the possibility of future fertility through cryopreservation of ovarian tissue. However, before such procedures can be recommended for clinical management, it is essential that future studies be performed to determine whether the oocytes retrieved from girls with Turner's syndrome have a normal chromosomal complement.

BACKGROUNDCancer therapy is one of many conditions which may diminish the ovarian reserve. Banking of human ovarian tissue has become an option for the preservation of female fertility. We have shown that vitrification is an excellent method to cryopreserve ovarian tissue. To carry out vitrification in a clinical setting, we have developed a clinical grade closed system to avoid direct contact of ovarian tissue with liquid nitrogen.METHODSOvarian tissue was obtained by biopsy from 12 consenting women undergoing Caesarean section. Tissues were vitrified in cryotubes, using dimethyl sulphoxide, 1,2-propanediol, ethylene glycol and polyvinylpyrrolidon as cryoprotectants. Non-vitrified and warmed-vitrified tissue was compared by light and electron microscopic morphology of the follicles within the tissues.RESULTSWe did not see any differences in the light or electron microscopic ultrastructure of oocytes between non-vitrified and vitrified tissues. No irreversible subcellular alterations in vitrified tissues were seen.CONCLUSIONSThe ultrastructure of follicles within the vitrified human ovarian tissue was well preserved using cryotube in a closed vitrification system to avoid direct contact of liquid nitrogen. The system is compatible with the European tissue directive.

While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by 18F-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.

Galliform and non-galliform birds express three immunoglobulin isotypes, IgM, IgA and IgY. Beyond this we should not generalize because differences in gene organization may have functional consequences reflected in the immune response. At present, studies on non-galliform birds are largely restricted to ducks. Ducks express an alternatively spliced form of their IgY heavy chain (upsilon) gene, the IgY(DeltaFc), that lacks the Fc region and Fc-associated secondary effector functions. It is not known how common the expression of the IgY(DeltaFc) is among birds, nor the functional consequences. It is also not known whether the unusual organization of the duck IgH locus, also shared with the chicken, having the gene order of mu, alpha and upsilon, with alpha inverted in the locus, is unique to the galloanseriform lineage. Ducks, like chickens, have a single immunoglobulin light chain of the lambda (lambda) type. Evidence suggests that ducks, like chickens, generate their immunoglobulin repertoire through a single functional rearrangement of the variable (V) region, and generate diversity through gene conversion from a pool of pseudogenes. In Southern blots of germline and rearranged bursal DNA, both the heavy and light chain loci of ducks appear to each undergo one major rearrangement event. For both heavy and light chains, the functional V region element and the pseudogenes appear to consist of a single gene family. Further analysis of 26 heavy chain joining (JH) and 27 light chain JL segments shows there is use of a single J segment in ducks, which is diversified presumably through somatic mutations and gene conversion events. Despite this limitation on the rearrangement of immunoglobulin genes, analysis of 26 DH and 122 VL sequences suggests that extensive sequence diversity is generated.