Effect of a collaborative interdisciplinary maternity care program on perinatal outcomes

Background:

The number of physicians providing maternity care in Canada is decreasing, and the rate of cesarean delivery is increasing. We evaluated the effect on perinatal outcomes of an interdisciplinary program designed to promote physiologic birth and encourage active involvement of women and their families in maternity care.

Methods:

We conducted a retrospective cohort study involving 1238 women who attended the South Community Birth Program in Vancouver, Canada, from April 2004 to October 2010. The program offers comprehensive, collaborative, interdisciplinary care from family physicians, midwives, community health nurses and doulas to a multiethnic, low-income population. A comparison group, matched for neighbourhood of residence, maternal age, parity and gestational age at delivery, comprised 1238 women receiving standard care in community-based family physician, obstetrician and midwife practices. The primary outcome was the proportion of women who underwent cesarean delivery.

Results:

Compared with women receiving standard care, those in the birth program were more likely to be delivered by a midwife (41.9% v. 7.4%, p < 0.001) instead of an obstetrician (35.5% v. 69.6%, p < 0.001). The program participants were less likely than the matched controls to undergo cesarean delivery (relative risk [RR] 0.76, 95% confidence interval [CI] 0.68–0.84) and, among those with a previous cesarean delivery, more likely to plan a vaginal birth (RR 3.22, 95% CI 2.25–4.62). Length of stay in hospital was shorter in the program group for both the mothers (mean ± standard deviation 50.6 ± 47.1 v. 72.7 ± 66.7 h, p < 0.001) and the newborns (47.5 ± 92.6 v. 70.6 ± 126.7 h, p < 0.001). Women in the birth program were more likely than the matched controls to be breastfeeding exclusively at discharge (RR 2.10, 95% CI 1.85–2.39).

Interpretation:

Women attending a collaborative program of interdisciplinary maternity care were less likely to have a cesarean delivery, had shorter hospital stays on average and were more likely to breastfeed exclusively than women receiving standard care.In the last 2 decades, Canada has seen a dramatic reduction in the number of physicians providing maternity care.^1,2 Reasons for this decline have included liability concerns, lifestyle issues and perceived competence.³ A large proportion of obstetricians and family physicians who practise maternity care will reach retirement age in the next 10 years.⁴ The reduction in maternity care providers has been linked with hospital closures in rural settings and increasing difficulty in accessing obstetric care for women in all settings.⁴ Although the introduction of regulated midwifery promises some relief, midwives currently attend less than 10% of births.⁵Recent times have also seen a dramatic increase in the rates of interventions during childbirth, particularly cesarean delivery, which has risen from 17% in the 1990s to 28% in 2009 in Canada.⁶ This increase has occurred despite a lack of evidence that maternal and neonatal outcomes are improved with cesarean delivery.^7–10 Increasing rates of surgical delivery have placed an added burden on care provider resources, because of the associated intrapartum and postpartum complications¹¹ and increased length of stay in hospital.¹²In addition, increasing diversity, especially in urban settings, has made the delivery of maternity care more challenging. In the province of British Columbia, 16% of the population speaks neither official language at home.¹³ This proportion is as high as 32% in Vancouver, the province’s largest city and the setting of our study. There is evidence that immigrant women are at increased risk of receiving obstetric interventions and less likely to breastfeed.^14,15In response to these issues, the South Community Birth Program was established to provide comprehensive, collaborative maternity care from family physicians, midwives, community health nurses and doulas to a multiethnic, low-income population. The program aims to promote physiologic birth while encouraging women and their families to assume an active role in their maternity care. In the current study, we evaluated the impact of the program on perinatal outcomes.     

Benzo[a]pyrene potentiates the pathogenesis of abdominal aortic aneurysms in apolipoprotein E knockout mice

The objective of this study was to determine the effect of benzo[a]pyrene (BaP), an abundant environmental polycyclic aromatic hydrocarbon compound, on the pathogenesis of abdominal aortic aneurysms (AAA). Earlier studies have shown that BaP promotes vasculopathy, including atherosclerosis, a predisposing factor for AAA development. In two experimental arms, 203 apolipoprotein E knockout (ApoE-/-) mice were evaluated in 4 groups: BaP, angiotensin II (AngII), BaP+AngII and control. Mice in the first arm were exposed to 5mg/kg/week of BaP for 42 days, and in the second arm to 0.71mg/kg daily for 60 days. In arm one, AAA incidence was higher in the BaP+AngII (14/28) versus AngII (8/27) group (p < 0.05), rupture (n=3) was observed only in BaP+AngII treated mice (p < 0.05). In the second arm, AAA incidence did not differ between AngII (17/30) and BaP+AngII (16/29) groups. However, intact AAA diameter was larger in the BaP+AngII (2.3 ± 0.1mm) versus AngII (1.9 ± 0.1mm) group (p < 0.05), but AAA rupture did not differ (p=NS). In both experimental arms, BaP+AngII mice showed increased expression of tumor necrosis factor alpha (TNF-α), cyclophilin A (Cyp A), and matrix metalloproteinase-9 (MMP9) (p < 0.05). No AAA occurred in control or BaP groups. These findings suggest the role of BaP exposure in potentiating AAA pathogenesis, which may have potential public health significance.     

Characterization of the microtubule proteome during post-diapause development of Artemia franciscana

The microtubule proteome encompasses tubulin and a diverse group of proteins which associate with tubulin upon microtubule formation. These proteins either determine microtubule organization and function or their activity is influenced by microtubule association. To characterize the microtubule proteome in Artemia franciscana, tubulin assembly was induced with taxol in vitro after 0 and 12 h of post-diapause development. Proteins obtained by extraction of microtubules with 0.5 M NaCl were electrophoresed in two-dimensional gels and analyzed by mass spectrometry. Fifty-five proteins were identified with 10 of these occurring at both developmental stages, and multiple isoforms were observed for some proteins of the Artemia proteome. Their functions include roles in membrane transport, metabolism, chaperoning and protein synthesis, thus reflecting physiological properties of encysted Artemia such as stress resistance and the ability to rapidly initiate post-diapause development. For example, chaperones may protect tubulin during encystment and facilitate folding in metabolically active embryos. Additionally, the interaction of metabolic enzymes with microtubules funnels reaction intermediates, potentially enhancing efficiency within biochemical processes. This study represents the first systematic characterization of a crustacean microtubule proteome. Although it is difficult to be certain that all protein associations documented herein occur in vivo, the results suggest how protein-protein interactions contribute to cytoplasmic organization while implying how Artemia embryos resist stress and remain capable of development once diapause terminates.     

The molecular machines that mediate microRNA maturation

MicroRNAs (miRNA) are small RNAs that regulate the translation of thousands of message RNAs and play a profound role in mammalian biology. Over the past 5 years, significant advances have been made towards understanding the pathways that generate miRNAs and the mechanisms by which miRNAs exert their regulatory functions. An emerging theme is that miRNAs are both generated by and utilized by large and complex macromolecular assemblies. Here, we review the biology of mammalian miRNAs with a focus on the macromolecular complexes that generate and control the biogenesis of miRNAs.     

The structures of frataxin oligomers reveal the mechanism for the delivery and detoxification of iron

Defects in the mitochondrial protein frataxin are responsible for Friedreich ataxia, a neurodegenerative and cardiac disease that affects 1:40,000 children. Here, we present the crystal structures of the iron-free and iron-loaded frataxin trimers, and a single-particle electron microscopy reconstruction of a 24 subunit oligomer. The structures reveal fundamental aspects of the frataxin mechanism. The trimer has a central channel in which one atom of iron binds. Two conformations of the channel with different metal-binding affinities suggest that a gating mechanism controls whether the bound iron is delivered to other proteins or transferred to detoxification sites. The trimer constitutes the basic structural unit of the 24 subunit oligomer. The architecture of this oligomer and several features of the trimer structure demonstrate striking similarities to the iron-storage protein ferritin. The data reveal how stepwise assembly provides frataxin with the structural flexibility to perform two functions: metal delivery and detoxification.     

Truncation attenuates molecular chaperoning and apoptosis inhibition by p26, a small heat shock protein from Artemia franciscana

The small heat shock proteins (sHSPs), which prevent irreversible protein denaturation and inhibit apoptosis, consist of an amino-terminus, the canonical α-crystallin domain, and a carboxy-terminal extension. It remains difficult, however, to define sHSP structure-function relationships and with this in mind p26, an sHSP from the crustacean Artemia franciscana, was truncated by deletion mutagenesis. Wild-type p26 cDNA and three truncated variants inserted into the eukaryotic expression vector pcDNA3.1/HisC were used to generate stably transfected 293H cells. p26 shielded transfected cells against death upon exposure to heat and oxidative stress. Truncation reduced chaperone activity, with cells synthesizing the p26 α-crystallin domain being the least resistant. Wild-type p26 inhibited apoptosis in transfected cells, with protection against oxidation-generated apoptosis being more effective than that against heat-induced apoptosis. Truncation reduced p26 apoptotic inhibitory activity, with the α-crystallin domain again being the least effective. The results show that a crustacean sHSP functions effectively in mammalian cells, demonstrating interchangeability of these proteins between distantly related organisms and indicating similarities in their mechanisms of action. Moreover, maximal activity was observed for full-length p26, indicating that structural elements required for chaperone activity and apoptosis inhibition reside throughout the protein.     

Acetylated tubulin is found in all microtubule arrays of two species of pine

Summary The distribution of acetylated tubulin in microtubule arrays of conifer cells was investigated by immunofluorescence techniques with 6-11B-1, a monoclonal antibody specific for posttranslationally acetylated -tubulins. In methacrylate sections ofPinus radiata andPinus conforta root tip cells, acetylated tubulin was detected in mitotic spindles, phragmoplasts, and cortical microtubules. Furthermore, staining of isolated, intact cells ofP. radiata andP. contorta indicated that all microtubule structures, including preprophase bands, prophase, metaphase and anaphase spindles, and phragmoplasts, contained some acetylated tubulin, and that the intensity of staining with 6-11B-1 was variable. For example, preprophase bands were lightly labelled, kinetochore fibres of anaphase spindles and phragmoplasts were heavily stained, and metaphase spindles had a granular appearance suggesting discontinuous acetylation of their constituent microtubules. This first report of the presence of acetylated tubulin in conifer cells is in contrast to our results with two species of angiosperms where no acetylated tubulin was detected. The significance of this and the variability of the intensity of staining in conifer arrays is discussed in terms of microtubule dynamics.     

Artemin is an RNA-binding protein with high thermal stability and potential RNA chaperone activity

Encysted embryos of the crustacean, Artemia franciscana, are among the most stress-resistant of all multicellular eukaryotes, due in part to massive amounts of p26, a small heat shock protein, that acts as a molecular chaperone. These embryos contain equally large amounts of another protein called artemin, of previously unknown function, that we report on here. Its thermal stability allows large-scale purification in about a day, using ammonium sulfate fractionation and incubation at 70 degrees C for 7 min, followed by gel filtration. The latter yields an artemin-RNA complex from which the pure protein, apo-artemin, was obtained by anion-exchange chromatography. We evaluated the possibility that artemin acts as a molecular chaperone for proteins, but obtained no evidence for that in vitro. The association of RNA with apo-artemin occurs at high temperatures and, although it is not yet clear whether artemin has a specific role as an RNA chaperone, it does bind non-polyadenylated RNAs which are then translated in vitro. Artemin-RNA is thermostable, some molecules resisting destruction after 30 min at 90 degrees C. The first order rate constant for denaturation and aggregation of artemin-RNA at 85 degrees C is 8.5 x 10(-3)min(-1), which compares well with other thermostable proteins of similar size ( approximately 500 kDa) such as the ferritins with which artemin has amino acid sequence similarity. The amount of artemin extracted from embryos that had been stored dry, under laboratory conditions, since 1951 is comparable to the amount in contemporary embryos, indicating its stability in situ, and supporting the in vitro heating studies.