Relationship between surrounding tissue morphology and directional collective migration of the posterior lateral line primordium in zebrafish

Collective cell migration, in which cells assemble and move together, is an essential process in embryonic development, wound healing and cancer metastasis. Chemokine signaling guides cell assemblies to their destinations. In zebrafish posterior lateral line primordium (PLLP), a model system for collective cell migration, it has been proposed that the chemokine ligand Cxcl12a secreted from muscle pioneer cells (MPs) and muscle fast fibers (MFFs), which are distributed along with the horizontal midline, binds to the receptor Cxcr4b in PLLP and that Cxcl12a–Cxcr4b signaling guides the anterior‐to‐posterior migration of PLLP along the horizontal midline. However, how the surrounding tissues affect PLLP migration remains to be elucidated. Here, we investigated the relationship between the PLLP and the surrounding tissues and found that a furrow between the dorsal and ventral myotomes is generated by Sonic hedgehog (Shh) signaling‐dependent MP and MFF differentiation and that the PLLP migrates in this furrow. When transient inhibition of Shh signaling impaired both the furrow formation and differentiation of cxcl12a‐expressing MPs/MFFs, directional PLLP migration was severely perturbed. Furthermore, when differentiated MPs and MFFs were ablated by femtosecond laser irradiations, the furrow remained and PLLP migration was relatively unaffected. These results suggest that the furrow formation between the dorsal and ventral myotomes is associated with the migratory behavior of PLLP.     

Characterization of Multidrug-Resistant Group B Streptococci with Reduced Penicillin Susceptibility Forming Small Non-Beta-Hemolytic Colonies on Sheep Blood Agar Plates

We isolated and characterized three multidrug-resistant clinical isolates of group B streptococci with reduced penicillin susceptibility (PRGBS) that formed small non-beta-hemolytic colonies on sheep blood agar plates but grew well on chocolate agar plates. They can be overlooked in the bacterial identification step, leading to clinical misdiagnosis and treatment failure.     

The behavior of ligament cells cultured on elastin and collagen scaffolds

The ruptured anterior cruciate ligament (ACL) does not heal spontaneously. Therefore, the development of new healing techniques employing tissue engineering is vital. One of the aspects related to tissue-engineered artificial ligaments is the type of cell to be used for the artificial ligament. In this study, ligament cells from the ACL and periodontal ligament (PDL) were evaluated. In addition, we prepared highly oriented extracellular matrix (ECM) fiber scaffolds that mimicked the structure of the ligament and examined the cellular responses to these scaffolds. Elastin-A and collagen were used as the ECM proteins. Although the cells from the PDL (PDL fibroblasts [PDLFs]) showed approximately 2.1-fold higher expression of alkaline phosphatase (ALP; marker of osteogenic differentiation) than the ACL cells, the expression of ligament-related genes (for type I collagen, type III collagen, and tenomodulin) did not differ between PDLFs and ACL cells. Furthermore, the cellular responses (expression pattern of ligament-related genes and ALP activity) to the ECM were similar between ACL cells and PDLFs. In particular, elastin-A upregulated ALP and downregulated tenomodulin (TeM; a ligament marker) in ligament cells. In contrast, collagen maintained TeM expression in ligament cells. These results suggest that elastin-A promotes the osteogenic differentiation of ligament cells and that collagen maintains the phenotype of ligament cells.     

Synthesis of self-assembled nucleobases and their anhydrous proton conductivity

We synthesized self-assembled nucleobases (SANs), such as 1-dodecylthymine (DOT) or 9-dodecyladenine (DOA), in which the nucleobase is immobilized on a long alkyl chain. The thermal stability of the SAN was increased by mixing with the acidic surfactant mono-dodecyl phosphate (MDP). Additionally, the SAN–MDP composite material showed proton conductivity of 4.62 × 10⁻⁴ S cm⁻¹ at 160 °C under anhydrous conditions. Additionally, the activation energy of the proton conduction was approximately 0.2 eV and this value was one order of magnitude higher than that of a typical humidified perfluorinated membrane, in which the proton can be moved by vehicle molecules, such as water molecules. In contrast, when the nucleobase without the immobilization of a long alkyl chain was mixed with MDP, the proton conductivity of these composite materials was two orders of magnitude less than that of the SAN–MDP composite. Therefore, we measured the XRD spectra of the SAN–MDP composite material. As a result, the SAN–MDP composite material showed a self-assembled structure with a two-dimensional proton conducting pathway, such as a lamellar structure, and that the anhydrous proton conduction was related to the interaction between the nucleobase of the SAN and the phosphate group of MDP. Consequently, the self-assembled nucleobase derivatives have the potential for use as novel anhydrous proton conductors with a two-dimensional proton conducting pathway.

We synthesized the proton conductive self-assembled nucleobase, such as 1-dodecylthymine and 9-dodecyladenine, in which the nucleobase is immobilized on a long alkyl chain.     

Validation of the Premature Infant Pain Profile-Revised (PIPP-R)

Objectives

To examine the construct validity, inter-rater reliability, and feasibility of the Premature Infant Pain Profile-Revised in infants of varying gestational ages, diagnoses, and procedures.

Methods

A prospective cross-over study with infants in three gestational age groups (26–31, 32–36, and ≥ 37 weeks) at three university-affiliated Neonatal Intensive Care Units in Canada. One hundred and ninety five bedside nurses and expert raters rated 202 hospitalized infants' pain during scheduled procedures using the measure. An expert rater and a nurse independently assessed infants' pain scores, using the Premature Infant Pain Profile-Revised, during 246 scheduled pairs of painful and non-painful procedures in the 202 infants. Nurses also completed a feasibility survey on using the measure in a clinical setting. To establish construct validity, pain scores were computed during painful and non-painful procedures. Inter-rater reliability between pain experts and nurses was calculated. A 5-point Likert scale was used to measure feasibility in terms of clarity, ease of use, and time to complete.

Results

Irrespective of gestational age, Premature Infant Pain Profile-Revised scores were significantly higher during painful procedures (mean 6.7 [SD 3.0]) compared to non-painful procedures (mean 4.8 [SD 2.9]). There was a high degree of correlation between nurses' and experts' ratings for painful (all R² = 0.92, p < 0.001) and non-painful (all R² = 0.87, p < 0.001) procedures. Mean scores on all feasibility indicators were equal to or higher than 3.8.

Discussion

The Premature Infant Pain Profile Revised has beginning construct validation, inter-rater reliability, and is considered feasible by clinicians. Concurrent validation studies should be considered.     

Experience of decortication for restrictive hemodynamics in adults with congenital heart disease

We treated four postoperative adults with congenital heart disease with severe restrictive hemodynamics (RH), and performed decortication (DC) with the anticipation of some relief of the RH. The catheterizations before DC showed high central venous, and right and left ventricular end‐diastolic pressures with “dip‐and‐plateau” pressure waveforms in the right and left ventricles. Upon myocardial histopathologic examination, moderate myocardial fibrotic change was demonstrated in two of three cases. DC led to decrease in type B natriuretic peptide levels in all cases, resulting in a decline in the central venous, right and left ventricular end‐diastolic pressures in three cases. Successful DC‐related relief of RH, dilatation of the ventricles with decline in central and end‐diastolic pressures, was observed in only one case. Our limited DC‐related hemodynamic improvement indicates a complexity of the severe RH, which may represent a unique intractable heart failure pathophysiology in intractable postoperative adult congenital heart disease.