PGT-HLA programmes for the cure of a sick sibling: clinical strategies for this challenging search.

The ultimate goal of a preimplantation genetic testing and human leukocyte antigen (PGT-HLA) matching programme is the birth of a healthy, HLA-compatible child for the treatment or cure of a sick sibling. Several authors have published successful cases of the births of children HLA-matched to siblings affected by different conditions and diseases. However, there are many reports of failed attempts. Couples seeking an HLA-matched sibling for their affected child look for positive outcomes in the shortest possible time. Nevertheless, there is no published consensus or guidelines with recommendations for these cases. Here, the authors aimed to analyse different approaches for these programmes, highlighting the most promising strategies for the families and fertility units. Furthermore, the authors mention a successful case of a PGT-HLA matching programme after a previous failed attempt following the strategies proposed. Which is the most cost-effective and time-efficient approach in a PGT-HLA matching programme?

Tetralin-induced and ThnR-regulated aldehyde dehydrogenase and beta-oxidation genes in Sphingomonas macrogolitabida strain TFA.

A new cluster of genes has been found downstream of the previously identified thnA2 gene. The gene products are similar to nonacylating aldehyde dehydrogenases (ThnG) and to proteins representing a complete beta-oxidation pathway (ThnH to ThnP). ThnG has a nonacylating NAD-dependent pimelic semialdehyde dehydrogenase activity that renders pimelic acid a seven-carbon dicarboxylic acid. For further metabolism via beta-oxidation, pimelic acid could be acylated by a constitutive acyl coenzyme A (acyl-CoA) ligase found in Sphingomonas macrogolitabida strain TFA or by ThnH, which would transfer CoA from a previously acylated molecule. The first round of beta-oxidation is expected to render glutaryl-CoA and acetyl-CoA. Glutaryl-CoA dehydrogenase (ThnN) would catalyze the oxidation and decarboxylation of glutaryl-CoA and yield crotonyl-CoA, which enters the central metabolism via acetyl-CoA. Mutagenesis studies have shown that these genes are not essential for growth on tetralin or fatty acids, although a thnG disruption mutant showed threefold less pimelic semialdehyde dehydrogenase activity. Transcriptional analysis indicated that these genes are induced by tetralin, subjected to catabolite repression, and regulated by the same regulatory factors previously identified to regulate other thn structural genes. In the present study, transcription initiation upstream of thnH and thnM has been detected by primer extension analysis, and putative promoters were identified by sequence analysis. In addition, binding of the activator ThnR to its putative binding sites at the PH and PM promoter regions has been characterized. These results provide a complete characterization of the biodegradation pathway of tetralin to central metabolites and describe the transcriptional organization of the thn operons in S. macrogolitabida strain TFA.

Effect of Group Embryo Culture under Low-Oxygen Tension in Benchtop Incubators on Human Embryo Culture: Prospective, Randomized, Controlled Trial.

To evaluate the efficacy of group embryo culture under low-oxygen tension in benchtop incubators on human embryo development in vitro. The study was designed as a prospective, patient blind, randomized, controlled trial of a complex intervention. One hundred forty-eight women undergoing IVF were recruited in our fertility practice and randomized into two groups: intervention group (study culture strategy) or control group (control culture strategy). Intervention group embryos were cultured grouped under low-oxygen tension in benchtop incubators while control group embryos were cultured individually under atmospheric oxygen tension in large-box incubators. Using the study culture strategy, there were a significantly higher implantation rate (65.1% vs 49.2%; RR, 1.42; 95% CI, 1.17-1.73) and live birth delivery rate per embryo transfer (52.7% vs 39.5%; RR, 1.33; 95% CI, 1.02-1.75) with the first fresh embryo transfer. Cumulative implantation rate (56.7% vs 43.6%; RR, 1.30; 95% CI, 1.05-1.62) and cumulative live birth rate per embryo transfer (47.4% vs 36.2%; RR, 1.31; 95% CI, 1.01-1.69) were also statistically significantly increased in the study culture strategy. Human embryos exposed to our study culture condition strategy had statistically significant increased cumulative implantation rate and cumulative live birth rate per embryo transferred. Our findings suggest that this strategy specially favours poor quality embryos. Clinical Trial Registration Number: NCT01904006.

Identification and functional characterization of Sphingomonas macrogolitabida strain TFA genes involved in the first two steps of the tetralin catabolic pathway.

Five genes involved in the two initial steps of the tetralin biodegradation pathway of Sphingomonas macrogolitabida strain TFA have been characterized. ThnA1A2 and ThnA3A4, components of the ring-hydroxylating dioxygenase, were encoded in divergently transcribed operons. ThnA1, ThnA2, and ThnA3 were essential for tetralin ring-hydroxylating dioxygenase activity. ThnB was identified as a dehydrogenase required for tetralin biodegradation.