Hyperpolarization-activated cyclic nucleotide-gated channels and T-type calcium channels confer automaticity of embryonic stem cell-derived cardiomyocytes

Regeneration of cardiac pacemakers is an important target of cardiac regeneration. Previously, we developed a novel embryonic stem (ES) cell differentiation system that could trace cardiovascular differentiation processes at the cellular level. In the present study, we examine expressions and functions of ion channels in ES cell-derived cardiomyocytes during their differentiation and identify ion channels that confer their automaticity. ES cell-derived Flk1(+) mesoderm cells give rise to spontaneously beating cardiomyocytes on OP9 stroma cells. Spontaneously beating colonies observed at day 9.5 of Flk1(+) cell culture (Flk-d9.5) were significantly decreased at Flk-d23.5. Expressions of ion channels in pacemaker cells hyperpolarization-activated cyclic nucleotide-gated (HCN)1 and -4 and voltage-gated calcium channel (Cav)3.1 and -3.2 were significantly decreased in purified cardiomyocytes at Flk-d23.5 compared with at Flk-d9.5, whereas expression of an atrial and ventricular ion channel, inward rectifier potassium channel (Kir)2.1, did not change. Blockade of HCNs and Cav ion channels significantly inhibited beating rates of cardiomyocyte colonies. Electrophysiological studies demonstrated that spontaneously beating cardiomyocytes at Flk-d9.5 showed almost similar features to those of the native mouse sinoatrial node except for relatively deep maximal diastolic potential and faster maximal upstroke velocity. Although approximately 60% of myocytes at Flk-d23.5 revealed almost the same properties as those at Flk-d9.5, approximately 40% of myocytes showed loss of HCN and decreased Cav3 currents and ceased spontaneous beating, with no remarkable increase of Kir2.1. Thus, HCN and Cav3 ion channels should be responsible for the maintenance of automaticity in ES cell-derived cardiomyocytes. Controlled regulation of these ion channels should be required to generate complete biological pacemakers.     

STAR family RNA-binding protein ASD-2 regulates developmental switching of mutually exclusive alternative splicing in vivo

Alternative splicing of pre-mRNAs greatly contributes to the spatiotemporal diversity of gene expression in metazoans. However, the molecular basis of developmental regulation and the precise sequence of alternative pre-mRNA processing in vivo are poorly understood. In the present study, we focus on the developmental switching of the mutually exclusive alternative splicing of the let-2 gene of Caenorhabditis elegans from the exon 9 form in embryos to the exon 10 form in adults. By visualizing the usage of the let-2 mutually exclusive exons through differential expression of green fluorescent protein (GFP) and red fluorescent protein (RFP), we isolated several switching-defective mutants and identified the alternative splicing defective-2 (asd-2) gene, encoding a novel member of the evolutionarily conserved STAR (signal transduction activators of RNA) family of RNA-binding proteins. Comparison of the amounts of partially spliced let-2 RNAs in synchronized wild-type and asd-2 mutant worms suggested that either of the introns downstream from the let-2 mutually exclusive exons is removed prior to the removal of the upstream ones, and that asd-2 promotes biased excision of intron 10 in the late larval stages. We propose that the developmental switching between alternative sequences of intron removal determines the ratio between the mature let-2 mRNA isoforms.     

What is a good midwife? Insights from the literature

Objective

to review the literature around what is considered to be a good midwife and in particular what women value in a midwife, in order to identify the gaps in the evidence for future research.

Design

this paper reviews the research in the area of interest over the past 30 years. The literature search focused on the concept of good midwife using synonyms and antonyms. The inclusion criteria included language (English or Italian). The examined databases were Medline, Maternity and Infant Care, Applied Social Sciences Index and Abstract and CINAHL.

Setting

studies conducted in high-income countries were taken into account. A focused review of papers which explicitly investigated what a good midwife means and a thematic analysis on what women value in a midwife were carried out.

Participants

different standpoints have been considered (midwives, student midwives, women and their partners), focusing in particular on women viewpoint.

Findings

the literature review reveals information about what is considered to be a good midwife from a range of perspectives and what women value in a midwife. A good midwife should possess several attributes: theoretical knowledge, professional competencies, personal qualities, communication skills and moral/ethical values. According to the thematic analysis around what childbearing women value in a midwife, frequent key-themes emerging from the literature were: support, possibility of choice, feeling in control and having appropriate information.

Key conclusions

the meaning of good midwife might change according to different actors involved in midwifery care and there is no agreement on the definition of what constitutes a good midwife. Furthermore, it is not clear if what women value in a good midwife corresponds to the midwives' perception of themselves as good professionals. There is a dearth of information around women's expectations and experiences specifically of a good midwife, and even less around whether this changes according to where they give birth.

Implications for practice

this literature review seeks to stimulate debate and reflection among midwives and professionals involved in the childbearing event, in order to fulfil women's expectations of their midwife and increase their satisfaction with the birth experience. The identification of the gaps in the evidence provided the starting point and allowed the development of research questions and methodology for an ongoing doctoral research. On the basis of the gaps in the evidence, the doctoral research will explore and seek to explain nulliparous women's expectations and experiences of a good midwife in the context of different planned place of birth, using a Grounded Theory methodology. It is also expected that the findings of this literature review will stimulate additional research in this area to ultimately inform midwifery practice and midwifery educational programmes.     

Professional and social support enhances maternal well-being in women with intellectual disability – A Swedish interview study

Objective

to gain a deeper understanding of the experience of professional and social support during pregnancy and childbirth among women with intellectual disability (ID) in Sweden.

Design/setting

an interview study among 10 women with ID, who had given birth within seven years. Two interviews were performed with each woman and data were analysed with qualitative content analysis.

Findings

the overarching theme was: Professional and social support enhances maternal well-being in women with intellectual disability. The women described that the midwife and other caregivers contributed to their own insights and supported their mother-to-be process. They were mostly satisfied with the professional care and support during pregnancy and childbirth, based on aspects such as continuity, competence and professional experience of the midwives but also professional approach and working methods. Dissatisfaction and confusion occurred when questions were left unanswered or when the women?s special needs were not taken into consideration. Family members, friends and colleagues could also have a supporting role and, together with the health staff, contribute to the well-being of the woman.

Conclusions

if professional support and care from midwives and other caregivers is adapted to the special needs of women with ID, it contributes to new insights, enhances well-being and supports the process of becoming a mother. Midwife-led continuity of care together with continuous social support should be offered to pregnant women with ID during pregnancy and childbirth.     

Midwives' knowledge of,attitudes towards and experiences of caring for women with intellectual disability during pregnancy and childbirth: A cross-sectional study in Sweden

Objective

to investigate midwives' knowledge of, attitudes towards and experiences of caring for women with intellectual disability (ID) during pregnancy and childbirth.

Design/setting

a cross-sectional study among six hundred midwives working at antenatal care and labour wards in Sweden.

Results

more than four out of five (81.5%) midwives had experience of caring for women with ID. Almost all midwives (97.1%) reported that caring for women with ID is different from caring for women without ID. Almost one-half (47.3%) had not received any education about pregnancy and delivery of women with ID, and a majority of the midwives (95.4%) requested evidence-based knowledge of women with ID in relation to childbirth. High proportion (69.7%) of the midwives were of the opinion that women with ID cannot satisfactorily manage the mother role, and more than one-third (35.7%) of the midwives considered that women with ID should not be pregnant and give birth at all. Most midwives partly/totally agreed that children of women with ID should grow up with their parents supported by the social authorities, but nearly one-fifth (19.1%) partly/totally agreed that the children should grow up in foster care.

Conclusions

even if the majority of midwives had experience of caring for women with ID, they were uncertain about how to adapt and give advice and they needed more knowledge about these women. Some midwives had negative attitudes towards childbearing among women with ID. Health Service providers should encourage midwives to update their knowledge and provide supportive supervision in midwifery care for women with ID.     

T2 values in the human brain: comparison with quantitative assays of iron and ferritin

Magnetic resonance (MR) imaging with a whole-body imager was performed in 10 fresh, unfixed whole human brains selected randomly from cadavers. All subjects were neurologically intact before death. T2 time constants were measured within the caudate nucleus, putamen, globus pallidus, cortical gray matter, subcortical white matter, and optic radiation. These regions were then excised, and T2 values were measured again with a 1.5-T MR spectrometer. Quantitative assays of iron, ferritin, and protein from these areas were then performed. Iron concentration varied significantly among brain regions, whereas ferritin and protein concentrations were constant among brain regions and among individuals. Neither iron nor ferritin concentration showed any consistent correlation with T2 values. Histologic examination of brain micro-sections with iron- and ferritin-specific stains of demonstrated poor correlation with biochemical assays of ferritin and iron concentrations. Results indicate that T2 values correlate poorly with iron and ferritin concentrations found in neurologically intact brains.     

Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission-computed tomography: Comparison with two-dimensional echocardiography

The configuration of the hypertrophied myocardium was evaluated by thallium-201 emission-computed tomography and 2-dimensional (2-D) sector scan in 10 patients with obstructive hypertrophic cardiomyopathy (HC), 10 with nonobstructive HC with giant negative T waves and 10 with concentric left ventricular (LV) hypertrophy. Thallium-201 myocardial imaging was reconstructed into multiple 12-mm-thick slices in 3 planes. The thickness ratio of the ventricular septum and the LV posterior wall in the short-axis plane and the ratio of the ventricular septum and the apical wall in the long-axis plane were analyzed. In the patients with obstructive HC the ventricular septal wall thickness index was increased, and the ratio of septal to posterior wall thickness index (1.45 ± 0.23) was greater than that in the patients with nonobstructive HC with giant negative T waves or in those with concentric LV hypertrophy (1.03 ± 0.20 and 0.98 ± 0.11, respectively; p <0.01 for each). In the patients with nonobstructive HC with giant negative T waves, increased apical wall thickness with apical cavity obliteration was characteristic, and the ratio of ventricular septal to apical wall thickness index (0.66 ± 0.14) was less than that in the patients with obstructive HC or in those with concentric LV hypertrophy (1.46 ± 0.38 and 1.04 ± 0.09, respectively; p <0.001 for each). In contrast, technically satisfactory 2-D sector scanning (83%) demonstrated various configurations of the hypertrophied ventricularseptum, but could not detect apical hypertrophy in 4 of the 10 patients with nonobstructive HC with giant negative T waves whose LV cineangiograms demonstrated apical hypertrophy. Thus, thallium-201 emission-computed tomography is useful in evaluating the characteristics of LV hypertrophy and assists 2-D sector scan, especially in patients with apical hypertrophy in HC.     

Acute early failure of a bioprosthesis after mitral valve replacement with completely preserved annuloventricular continuity

We report a case of acute early bioprosthetic failure after mitral valve replacement with completely preserved annuloventricular continuity. A 77-year-old man with left ventricular dysfunction underwent double valve replacement with Carpentier-Edwards pericardial bioprostheses. Routine postoperative echocardiography revealed 1.4 cm² of estimated mitral valve area, and computed tomography revealed a large thrombus in the left atrium. Transesophageal echocardiography showed a restricted opening of the bioprosthetic leaflets. After a month of strict anticoagulation therapy, cusp mobility improved, with a calculated mitral valve area of 3.5 cm²; and the left atrial thrombus had almost disappeared 2 months after initiation of therapeutic anticoagulation. Surgeons should be watchful for bioprosthetic thrombosis in patients with left ventricular dysfunction who undergo mitral valve replacement with a preserved mitral subvalvular apparatus.