Examining provider practice-level disparities in delivery outcomes among patients with a history of Cesarean Delivery

BACKGROUND

Choosing whether to pursue a trial of labor after cesarean (TOLAC) or scheduled repeat cesarean delivery (SRCD) requires prenatal assessment of risks and benefits. Providers and patients play a central role in this process. However, the influence of provider-associated characteristics on delivery methods remains unclear. We hypothesized that different provider practice groups have different obstetric outcomes in patients with one prior cesarean delivery (CD).

METHODS

This was a retrospective cohort study of deliveries between April 29, 2015 - April 29, 2020. Subjects were divided into three cohorts: SRCD, successful VBAC, and unsuccessful VBAC (patients who chose TOLAC but had a CD). Disparities were reviewed between five different obstetric provider practice groups, determined from a breakdown of different providers delivering at the study site during the study period. Proportional differences were examined using Chi-squared tests and logistic regression models.

RESULTS

1,439 deliveries were included in the study. There were significant proportional disparities between patients in the different groups. Specifically, patients from Group D were significantly more likely to undergo successful VBAC, while patients seeing a provider from Group A were more likely to deliver by SRCD. In our multivariate analysis of successful versus unsuccessful VBAC, patients from Group D had greater odds ratios of successful VBAC compared to Group A. Patients delivered by Group E had a significantly lower odds ratio of successful VBAC.

CONCLUSION

This study suggests an association between provider practice groups and delivery outcomes among patients with one prior CD. These data contribute to a growing body of literature around patient choice in pregnancy and the interplay of patients and providers. These findings help to guide future investigations to improve outcomes among patients with a history of CD.

Scalings of Rayleigh-Taylor Instability at Large Viscosity Contrasts in Porous Media

The scalings of the Rayleigh-Taylor instability are studied numerically for porous media flows when the denser fluid lying on top of the less dense one is also much more viscous. We show that, above a critical value of the viscosity ratio M, a symmetry breaking of the buoyancy-driven fingers is observed as they extend much further downward than upward. The asymmetry ratio scales as M^{1/2} while the asymptotic flux across the initial contact line, quantifying the mixing between the two fluids, scales as M^{-1/2}. A new fingering mechanism induced by large viscosity contrasts is identified and shows good agreement with experimentally observed dynamics.

Constitutive UCP3 overexpression at physiological levels increases mouse skeletal muscle capacity for fatty acid transport and oxidation

Uncoupling protein 3 (UCP3) expression is directly correlated to fatty acid oxidation in skeletal muscle. UCP3 has been hypothesized to facilitate high rates of fatty acid oxidation, but evidence thus far is lacking. Our aim was to investigate the effects of UCP3 overexpression and ablation on fatty acid uptake and metabolism in muscle of mice having congenic backgrounds. In mice constitutively expressing the UCP3 protein (human form) at levels just over twofold higher than normal (230% of wild-type levels), indirect calorimetry demonstrated no differences in total energy expenditure (VO2), but a shift toward increased fat oxidation compared with wild-type (WT) mice. Metabolic efficiency (gram weight gain/kcal ingested) was similar between Ucp3 overexpressors, WT and Ucp3 (-/-) mice. In muscle of Ucp3-tg mice, plasma membrane fatty acid binding protein (FABPpm) content was increased compared with WT mice. Although hormone-sensitive lipase activity was unchanged across the genotypes, there were increases in carnitine palmitoyltransferase I, beta-hydroxyacylCoA dehydrogenase, and citrate synthase activities and decreases in intramuscular triacylglycerol in muscle of Ucp3-tg mice. There were no differences in muscle mitochondrial content. High-energy phosphates and total muscle carnitine and CoA were also greater in Ucp3-tg compared with WT mice. Taken together, the findings demonstrate an increased capacity for fat oxidation in the absence of significant increases in thermogenesis in Ucp3-tg mice. Findings from Ucp3 (-/-) mice revealed few differences compared with WT mice, consistent with the possibility of compensatory mechanisms. In conjunction with our observed increases in CoA and carnitine in muscle of Ucp3 overexpressors, the findings support the hypothesized role for Ucp3 in facilitating fatty acid oxidation in muscle.

The N-terminal and C-terminal domains of RAP1 are dispensable for chromatin opening and GCN4-mediated HIS4 activation in budding yeast

Repressor activator protein 1 (RAP1) assists GCN4-mediated HIS4 activation by overcoming some repressive aspect of chromatin structure to facilitate GCN4 binding. RAP1 also participates in other nuclear processes, and discrete domains of RAP1 have been shown to have specific properties including DNA binding, DNA bending, transcriptional activation, and silencing and telomere functions. To investigate whether specific domains of RAP1 are required to "open" chromatin and help GCN4 to activate the HIS4 gene, we examined the abilities of different truncated RAP1 proteins to perturb positioned nucleosomes via a nucleosomal RAP1 site in a yeast episome in vivo, and we tested HIS4 activation in yeast strains harboring truncated RAP1 mutants. We found that neither the DNA bending domain nor the putative activation domain of RAP1 is required for its ability to perturb the chromatin structure of a plasmid containing a RAP1 site. Similarly, neither the putative activation domain nor the N-terminal DNA-bending domain was required for GCN4-mediated activation of HIS4. We also used a rap1(ts) mutant to show that continuous occupancy of the HIS4 promoter by RAP1 is required for GCN4-mediated gene activation.

Patterns of accidental fractures and dislocations in Saudi Arabia

A study of 4320 confirmed cases of accidental fractures and dislocations was conducted. The aims were to study and analyse the patterns of fractures and dislocations, age and sex distribution, and the cause of injury. It was found that dislocations are relatively uncommon, upper limb injuries are more frequent than lower limb and axial skeleton injuries, and the radius and ulna were the most commonly fractured bones. A young adult male was found to be the person most at risk of an injury, and children of both sexes were the second age group most commonly involved. The overall results showed that road traffic accidents accounted for 14 per cent of the cases, but this incidence increased in the young adult and the over 40 years age group, and this cause was more evident with the more serious fractures, such as those of the axial skeleton and lower limbs.