Mobile eye tracking applied as a tool for customer experience research in a crowded train station.

Train stations have increasingly become crowded, necessitating stringent requirements in the design of stations and commuter navigation through these stations. In this study, we explored the use of mobile eye tracking in combination with observation and a survey to gain knowledge on customer experience in a crowded train station. We investigated the utilization of mobile eye tracking in ascertaining customers' perception of the train station environment and analyzed the effect of a signalization prototype (visual pedestrian flow cues), which was intended for regulating pedestrian flow in a crowded underground passage. Gaze behavior, estimated crowd density, and comfort levels (an individual's comfort level in a certain situation), were measured before and after the implementation of the prototype. The results revealed that the prototype was visible in conditions of low crowd density. However, in conditions of high crowd density, the prototype was less visible, and the path choice was influenced by other commuters. Hence, herd behavior appeared to have a stronger effect than the implemented signalization prototype in conditions of high crowd density. Thus, mobile eye tracking in combination with observation and the survey successfully aided in understanding customers' perception of the train station environment on a qualitative level and supported the evaluation of the signalization prototype the crowded underground passage. However, the analysis process was laborious, which could be an obstacle for its practical use in gaining customer insights.

Design and synthesis of some novel hybrid molecules based on 4-thiazolidinone bearing pyridine-pyrazole scaffolds: molecular docking and molecular dynamics simulations of its major constituent onto DNA gyrase inhibition.

Due to multidrug resistance, microbial infections have become significant on a global level. As infections caused by several resistant bacteria and fungi severely harm mankind, scientists have developed new antibiotics to combat these infections. In order to develop novel antimicrobial agents, a series of 4-thiazolidinone-based 5-arylidene hybrids (5a-o) have been designed and synthesized to evaluate their antibacterial and antifungal activities. For the determination of the structure of a novel synthesized hybrid, various spectral techniques, e.g., IR, 1H NMR, 13C NMR, and Mass spectroscopy, were used. Two bacterial gram-negative (Escherichia coli and Pseudomonas aeruginosa), two gram-positive strains (Staphylococcus aureus and Streptococcus pyogenes), and one fungal strain (Candida albicans) were used to evaluate antimicrobial activity. Compounds 5c, 5g, and 5i were effective due to their MIC values of 62.5 µg/mL against tested bacterial strains (S. pyogenes (5c), P. aeruginosa (5g), and E. coli (5i), respectively.) and 250 µg/mL against C. albicans fungal strains, respectively. Additionally, molecular docking and 100 ns molecular dynamic simulations were carried out to investigate the stability of molecular contacts and to establish how the newly synthesized inhibitors fit together in the most stable conformations.

Results of in situ fixation of Andersson lesion by posterior approach in 35 cases.

STUDY OBJECTIVE: Due to the rarity of the Andersson lesion (AL), the literature is ambiguous regarding the type of surgical fixation, need for debridement and deformity correction. The purpose of this retrospective study is to evaluate the efficacy, feasibility and functional outcome of posterior fixation in AL. MATERIALS AND METHODS: This study included 35 patients having thoracolumbar AL operated for in situ fixation and fusion with minimum of 24-month follow-up. VAS (Visual Analogue Score) back pain, ODI (Oswestry Disability Index), Frankel's grade were compared and analyzed. Union status was noted with complications. RESULTS: The mean age of 35 patients was 56.34(± 11.3) years with average follow-up of 51.49 months. Two patients had AL at two levels. 27/37 AL were at discal level. Average estimated blood loss (EBL) was 276.43 ml and duration of surgery was 130.43 min. On an average, operated segments needed 7.77 screws. There were ten minor complications without long-term sequel. Neurological improvement was noted in 30 patients. Average preoperative VAS score improved from 8.69 to 3.14, ODI score improved from 68.76 to 18.77 at final follow-up which were significant (p < 0.05). There was significant improvement in Frankel's grading (Z = - 4.354, P = 0.00). CONCLUSIONS: Surgical management of AL by posterior approach and posterior stabilization can give satisfactory results without the need of extensive anterior reconstruction, bone grafting or deformity correction procedures without added morbidity and complications.

Facial Appearance Dissatisfaction Explains Differences in Zoom Fatigue.

Viewing self-video during videoconferences potentially causes negative self-focused attention that contributes to virtual meeting (VM) or "Zoom" fatigue. The present research examines this proposition, focusing on facial dissatisfaction-feeling unhappy about one's own facial appearance-as a potential psychological mechanism of VM fatigue. A study of survey responses from a panel of 613 adults found that VM fatigue was 14.9 percent higher for women than for men, and 11.1 percent higher for Asian than for White participants. These gender and race/ethnicity differences were found to be mediated by facial dissatisfaction. This study replicates earlier VM fatigue research, extends the theoretical understanding of facial dissatisfaction as a psychological mechanism of VM fatigue, and suggests that practical approaches to mitigating VM fatigue could include implementing technological features that reduce self-focused attention during VMs (e.g., employing avatars).

Thoracic Spine Stenosis: Does Ultrasonic Osteotome Improve Outcome in Comparison to Conventional Technique?

INTRODUCTION: To investigate the efficacy of Ultrasonic Bone Scalpel (UBS) in thoracic spinal stenosis (TSS) in comparison to traditional technique. MATERIAL AND METHODS: A total of 55 patients who had undergone conventional surgery (Group A) are compared with 45 patients of UBS (Group B) in TSS. The primary outcome measure of Modified Japanese Orthopaedic Association score (m JOA) with neurological complications and dural injury were assessed. Secondary outcome measures of total blood loss (TBL), time duration of surgery (ORT) and length of hospital stay (LHS) were analysed. RESULTS: The pre-operative mJOA score 5.00(4.00-6.00) in the group A and 5.00(4.00-6.00) in the group B improved to 7.00(7.00-8.00) in the group A and 9.00(9.00-10.00) in the group B, respectively (P<0.001) at final average follow-up of 117.55 months for group A and 75.69 months in group B. More significant grade of myelopathy improvement and mJOA recovery rate (RR) were noted in group B. The TBL, ORT and LHS were more favourable in group B as compared to group A (p<0.0001). The group A had 9 (16.36%) neurological deficits compared to 2 (4.44%) in group B (p<0.001). Dural tears occurred in both groups (A=11, B=9). It was more frequent and not repairable in group A but without significant statistical difference. CONCLUSION: UBS can reduce neurological deficits and improve outcomes in TSS. Secondarily, reduced blood loss, lesser surgical time and reduced LHS are significant added advantages of this new technology.

The mouse Gene Expression Database (GXD): 2021 update.

The Gene Expression Database (GXD; www.informatics.jax.org/expression.shtml) is an extensive and well-curated community resource of mouse developmental gene expression information. For many years, GXD has collected and integrated data from RNA in situ hybridization, immunohistochemistry, RT-PCR, northern blot, and western blot experiments through curation of the scientific literature and by collaborations with large-scale expression projects. Since our last report in 2019, we have continued to acquire these classical types of expression data; developed a searchable index of RNA-Seq and microarray experiments that allows users to quickly and reliably find specific mouse expression studies in ArrayExpress (https://www.ebi.ac.uk/arrayexpress/) and GEO (https://www.ncbi.nlm.nih.gov/geo/); and expanded GXD to include RNA-Seq data. Uniformly processed RNA-Seq data are imported from the EBI Expression Atlas and then integrated with the other types of expression data in GXD, and with the genetic, functional, phenotypic and disease-related information in Mouse Genome Informatics (MGI). This integration has made the RNA-Seq data accessible via GXD's enhanced searching and filtering capabilities. Further, we have embedded the Morpheus heat map utility into the GXD user interface to provide additional tools for display and analysis of RNA-Seq data, including heat map visualization, sorting, filtering, hierarchical clustering, nearest neighbors analysis and visual enrichment.

Thoracic Spine Stenosis: Does Ultrasonic Osteotome Improve Outcome in Comparison to Conventional Technique?

@#Introduction: To investigate the efficacy of Ultrasonic Bone Scalpel (UBS) in thoracic spinal stenosis (TSS) in comparison to traditional technique. Materials and methods: A total of 55 patients who had undergone conventional surgery (Group A) are compared with 45 patients of UBS (Group B) in TSS. The primary outcome measure of Modified Japanese Orthopaedic Association score (m JOA) with neurological complications and dural injury were assessed. Secondary outcome measures of total blood loss (TBL), time duration of surgery (ORT) and length of hospital stay (LHS) were analysed. Results: The pre-operative mJOA score 5.00(4.00-6.00) in the group A and 5.00(4.00-6.00) in the group B improved to 7.00(7.00-8.00) in the group A and 9.00(9.00-10.00) in the group B, respectively (P<0.001) at final average follow-up of 117.55 months for group A and 75.69 months in group B. More significant grade of myelopathy improvement and mJOA recovery rate (RR) were noted in group B. The TBL, ORT and LHS were more favourable in group B as compared to group A (p<0.0001). The group A had 9 (16.36%) neurological deficits compared to 2 (4.44%) in group B (p<0.001). Dural tears occurred in both groups (A=11, B=9). It was more frequent and not repairable in group A but without significant statistical difference. Conclusions: UBS can reduce neurological deficits and improve outcomes in TSS. Secondarily, reduced blood loss, lesser surgical time and reduced LHS are significant added advantages of this new technology.

Urinary Calcium for Tracking Bone Loss and Kidney Stone Risk in Space.

INTRODUCTION: Urinary calcium (Uca) levels in space reflect bone loss and kidney stone risk and could be measured using portable devices. This project evaluated the repeatability of Uca measurements to assess how many repeated measurements would be needed to detect significant urinary calcium elevations in space.METHODS: A total of six subjects collected 24-h urine samples weekly for 8 wk and took 500 mg of oral calcium carbonate and 400 IU of vitamin D daily in week 7 and 8. Uca concentration was analyzed using a calcein-based system. The effect of the intake of calcium and vitamin D on Uca levels and the correlation between first void concentration and 24-h mass were assessed with linear mixed effect models. The reproducibility coefficient (RPC) for Uca was determined using Bland-Altman analysis on pairs of measurements at different time points.RESULTS: Oral supplementation did not significantly affect 24-h mass. First void concentration correlated with 24-h mass. The 24-h mass RPCs were 167.0, 116.8, and 108.1 mg for 1-, 2-, and 3-wk average measurements. First void concentration RPCs were 90.6, 76.6, and 72.8 mg L1. Skylab astronauts 24-h mass increased by 88.9 76.0, 123.5 58.3, 142.2 56.5, and 159.9 83.4 mg after 1, 2, 3, and 4 wk in flight.DISCUSSION: Averaging multiple Uca measurements reduced variability effectively and allowed increases likely to be seen in space to be detected. Consecutive Uca measurements could be tracked over time in space to assess the effectiveness of the countermeasure program. First void concentration could potentially be used rather than 24-h collections.Ren J, Stankovic AS, Knaus DA, Phillips SD, Kynor DB, Buckey JC. Urinary calcium for tracking bone loss and kidney stone risk in space. Aerosp Med Hum Perform. 2020; 91(9):689696.

Cauda Equina Syndrome: A Review of 15 Patients Who Underwent Percutaneous Transforaminal Endoscopic Lumbar Discectomy (PTELD) Under Local Anaesthesia.

INTRODUCTION: To analyse the results of Cauda Equina Syndrome (CES) operated by Percutaneous Transforaminal Endoscopic Lumbar Discectomy (PTELD). MATERIAL AND METHODS: The study is a retrospective series of 15 patients operated by PTELD. Bladder dysfunction was classified as incomplete CES (CESI) and complete CES retention (CESR). Bladder / motor recovery rate and its timing, Oswestry Disability Index (ODI), Visual Analogue Score (VAS), patient satisfaction index, and sexual dysfunction were used to measure the outcome objectively. Additionally, in CESR patients, post-void residual (PVR) urine was measured by sonography. Complications and technical problems were noted. RESULTS: There were ten patients of CESI and five patients of CESR. The average follow-up was 20.33(12.05) months. Bladder symptoms recovery was 100%, and motor recovery was 80%. VAS for back pain recovered to 0.53(0.52) from 8(2.39). VAS for leg pain recovered to 0.13(0.35) from 9.20(1.32). ODI improved to 6.07(2.85) from 77.52(13.20). The time to the recovery of bladder function was 1.47(1.55) days. All CESR patient's abnormal PVR urine was normalised at five weeks post-operative. No complications were reported. However, five technical executional problems occurred. CONCLUSION: PTELD can be considered for CES treatment due to its substantial and quick recovery advantages. However, more evidence support is needed to make it a practice recommendation.

Outdoor Air Pollution and New-Onset Airway Disease. An Official American Thoracic Society Workshop Report.

Although it is well accepted that air pollution exposure exacerbates preexisting airway disease, it has not been firmly established that long-term pollution exposure increases the risk of new-onset asthma or chronic obstruction pulmonary disease (COPD). This Workshop brought together experts on mechanistic, epidemiological, and clinical aspects of airway disease to review current knowledge regarding whether air pollution is a causal factor in the development of asthma and/or COPD. Speakers presented recent evidence in their respective areas of expertise related to air pollution and new airway disease incidence, followed by interactive discussions. A writing committee summarized their collective findings. The Epidemiology Group found that long-term exposure to air pollution, especially metrics of traffic-related air pollution such as nitrogen dioxide and black carbon, is associated with onset of childhood asthma. However, the evidence for a causal role in adult-onset asthma or COPD remains insufficient. The Mechanistic Group concluded that air pollution exposure can cause airway remodeling, which can lead to asthma or COPD, as well as asthma-like phenotypes that worsen with long-term exposure to air pollution, especially fine particulate matter and ozone. The Clinical Group concluded that air pollution is a plausible contributor to the onset of both asthma and COPD. Available evidence indicates that long-term exposure to air pollution is a cause of childhood asthma, but the evidence for a similar determination for adult asthma or COPD remains insufficient. Further research is needed to elucidate the exact biological mechanism underlying incident childhood asthma, and the specific air pollutant that causes it.

Intraoperative Goal-Directed Anesthetic Management of the Patient with Severe Pulmonary Hypertension.

BACKGROUND It is very challenging for anesthesiologists to manage patients with pulmonary hypertension undergoing general anesthesia for elective or emergent surgeries. CASE REPORT We present a patient with severe pulmonary hypertension going through a major robotic thoracic surgery. CONCLUSIONS A goal-directed anesthesia management algorithm based on serial stroke volume (SV) values obtained from FloTrac (Edwards Lifesciences, LLC.) minimally invasive arterial pressure sensor was utilized in an attempt to reduce the anesthetic and surgical risk associated with severe pulmonary hypertension.

The mouse Gene Expression Database (GXD): 2017 update.

The Gene Expression Database (GXD; www.informatics.jax.org/expression.shtml) is an extensive and well-curated community resource of mouse developmental expression information. Through curation of the scientific literature and by collaborations with large-scale expression projects, GXD collects and integrates data from RNA in situ hybridization, immunohistochemistry, RT-PCR, northern blot and western blot experiments. Expression data from both wild-type and mutant mice are included. The expression data are combined with genetic and phenotypic data in Mouse Genome Informatics (MGI) and made readily accessible to many types of database searches. At present, GXD includes over 1.5 million expression results and more than 300 000 images, all annotated with detailed and standardized metadata. Since our last report in 2014, we have added a large amount of data, we have enhanced data and database infrastructure, and we have implemented many new search and display features. Interface enhancements include: a new Mouse Developmental Anatomy Browser; interactive tissue-by-developmental stage and tissue-by-gene matrix views; capabilities to filter and sort expression data summaries; a batch search utility; gene-based expression overviews; and links to expression data from other species.

Potential immunomodulatory effects of non-dialyzable materials of cranberry extract in poultry production.

Studies on effects of cranberry products in animals, especially in chickens, are very scarce or even lacking. This study investigated the immunomodulatory effect of high molecular weight non-dialyzable materials (NDMs) of cranberry extract. The in vitro antioxidant and anti-inflammatory activities were investigated. The ability of NDMs (0, 1, 2, or 4 mg/mL) to enhance phagocytic activities was also evaluated using chicken heterophils (CHEs) against Staphylococcus aureus Furthermore, a broiler model was used to determine the effect of NDMs on the humoral immune response. Seven-d-old chicks were vaccinated with the infectious bursal disease virus (IBDV) vaccine S-706, and treated orally with 0, 2, 4, or 8 mg/mL/bird NDMs for five consecutive days. Serum immunoglobulin level (Ig), and antibody concentration against IBDV, infectious bronchitis virus (IBV), Newcastle disease virus (NDV), and avian reovirus (ARV) were measured weekly by enzyme-linked immunosorbent assay (ELISA). NDMs showed >five-fold higher antioxidant activity (oxygen radical absorbance capacity = 222.7 mg trolox/g) than the commercial raw cranberry juice from which it derived (oxygen radical absorbance capacity = 39.6 mg trolox/g). Likewise, NDMs demonstrated anti-inflammatory activities comparable to Naproxen but better than those of Ibuprofen. The susceptibility of S. aureus to phagocytosis by CHEs increased significantly (P < 0.05) at 4 mg/mL NDMs in the medium. While no intracellular bacteria were counted in CHEs after phagocytosis in the presence of 2 and 4 mg/mL NDMs, 1 mg/mL NDMs demonstrated a significant (P < 0.05) intracellular killing activity in CHEs against S. aureus compared to the untreated CHEs. Results from the in vivo studies indicated that birds receiving 2 and 4 mg/mL/bird NDMs had a higher serum IgM level (P < 0.05), and their antibody titers against IBDV tended to increase with NDMs administration (P = 0.06) on d 35. These results suggest that NDMs enhances bacterial susceptibility to immuno-defense mechanisms, and may be useful as immunomodulators against infections.

Motor unit firing rates of the gastrocnemii during maximal and sub-maximal isometric contractions in young and old men.

The triceps surae comprises an important group of muscles for human posture and gait. The soleus unlike other limb muscles shows atypical lower firing rates in both old and young adults across various voluntary strength levels, including maximal contractions. The other portion of the triceps surae, the gastrocnemii has not been explored in aging, and despite anatomic, histochemical and age-related morphological differences, they share many common functions with soleus. During multiple visits, 10 active young (23-33years) and 10 active old participants (76-86years) performed a series of plantar flexor isometric contractions at a range of contraction intensities including maximal voluntary contraction (MVC) with tungsten microelectrodes inserted into the lateral (LG) and medial (MG) gastrocnemius. Despite equal and near maximal voluntary activation (VA) (∼98%), MVC torque was ∼46% lower, twitch tension was ∼34% lower, and contractile speed was ∼15% slower in the old men compared with the young. At all isometric torque levels tested (25, 50, 75 and 100% MVC) there were no statistically significant differences in mean motor unit firing rates (MUFRs) between young and old men. In both groups, the range of mean MU firing rates was similar (∼8Hz at 25% MVC to ∼22Hz at 100% MVC). The structural age-related changes in the gastrocnemii are not reflected in neural drive adaptations, indicating that MUFRs may not be a common feature with aging and other factors such as habitual use or anatomical location may be influential.

Disseminated staphylococcal infection in an immunocompetent adult: A case report

@#<p style="text-align: justify;">Septic pulmonary embolism is an uncommon disorder in which septic thrombi are mobilized from an infectious nidus and transported in the vascular system of the lungs. We report a case of a 52-year-old immunocompetent female who suffered from septic pulmonary embolism associated with polymyositis, deep venous thrombosis and pericardial effusion. Oxacillin-sensitive staphylococcus aureus (MSSA) was isolated from her sputum. Clinical presentation improved after incision of the muscle abscess and vancomycin treatment.</p>

Drug-repositioning screening identified piperlongumine as a direct STAT3 inhibitor with potent activity against breast cancer.

Signal transducer and activator of transcription (STAT) 3 regulates many cardinal features of cancer including cancer cell growth, apoptosis resistance, DNA damage response, metastasis, immune escape, tumor angiogenesis, the Warburg effect and oncogene addiction and has been validated as a drug target for cancer therapy. Several strategies have been used to identify agents that target Stat3 in breast cancer but none has yet entered into clinical use. We used a high-throughput fluorescence microscopy search strategy to identify compounds in a drug-repositioning library (Prestwick library) that block ligand-induced nuclear translocation of Stat3 and identified piperlongumine (PL), a natural product isolated from the fruit of the pepper Piper longum. PL inhibited Stat3 nuclear translocation, inhibited ligand-induced and constitutive Stat3 phosphorylation, and modulated expression of multiple Stat3-regulated genes. Surface plasmon resonance assay revealed that PL directly inhibited binding of Stat3 to its phosphotyrosyl peptide ligand. Phosphoprotein antibody array analysis revealed that PL does not modulate kinases known to activate Stat3 such as Janus kinases, Src kinase family members or receptor tyrosine kinases. PL inhibited anchorage-independent and anchorage-dependent growth of multiple breast cancer cell lines having increased pStat3 or total Stat3, and induced apoptosis. PL also inhibited mammosphere formation by tumor cells from patient-derived xenografts. PL's antitumorigenic function was causally linked to its Stat3-inhibitory effect. PL was non-toxic in mice up to a dose of 30 mg/kg/day for 14 days and caused regression of breast cancer cell line xenografts in nude mice. Thus, PL represents a promising new agent for rapid entry into the clinic for use in treating breast cancer, as well as other cancers in which Stat3 has a role.

Microsatellite primer development for post oak, Quercus stellata (Fagaceae).

PREMISE OF THE STUDY: The American Cross Timbers forest ecosystem runs from southeastern Kansas to Central Texas and is primarily composed of post oak (Quercus stellata). This old-growth forest currently occupies only about 2% of its ancestral range. To facilitate genetic research on this species, we developed microsatellite primers specific to post oak from reduced genomic libraries. • METHODS AND RESULTS: Two Q. stellata individuals, sampled from the northern and southern range of the post oak forest, were subject to genomic reduction and 454 pyrosequencing. Bioinformatic analysis identified putative microsatellites from which 12 polymorphic primer sets were screened on three populations. The number of alleles observed ranged from five to 20 across all populations, while observed and expected heterozygosity values ranged from 0.05 to 0.833 and 0.236 to 0.893, respectively, within individual populations. • CONCLUSIONS: We report the development of microsatellite markers, specific to post oak, to aid the study of genetic diversity and population structure of extant forest remnants.

Mmp25ß facilitates elongation of sensory neurons during zebrafish development.

Matrix metalloproteinases (MMPs) are a large and complex family of zinc-dependent endoproteinases widely recognized for their roles in remodeling the extracellular matrix (ECM) during embryonic development, wound healing, and tissue homeostasis. Their misregulation is central to many pathologies, and they have therefore been the focus of biomedical research for decades. These proteases have also recently emerged as mediators of neural development and synaptic plasticity in vertebrates, however, understanding of the mechanistic basis of these roles and the molecular identities of the MMPs involved remains far from complete. We have identified a zebrafish orthologue of mmp25 (a.k.a. leukolysin; MT6-MMP), a membrane-type, furin-activated MMP associated with leukocytes and invasive carcinomas, but which we find is expressed by a subset of the sensory neurons during normal embryonic development. We detect high levels of Mmp25ß expression in the trigeminal, craniofacial, and posterior lateral line ganglia in the hindbrain, and in Rohon-Beard cells in the dorsal neural tube during the first 48 h of embryonic development. Knockdown of Mmp25ß expression with morpholino oligonucleotides results in larvae that are uncoordinated and insensitive to touch, and which exhibit defects in the development of sensory neural structures. Using in vivo zymography, we observe that Mmp25ß morphant embryos show reduced Type IV collagen degradation in regions of the head traversed by elongating axons emanating from the trigeminal ganglion, suggesting that Mmp25ß may play a pivotal role in mediating ECM remodeling in the vicinity of these elongating axons.

TP73, an under-appreciated player in non-Hodgkin lymphoma pathogenesis and management.

The TP73 gene is a member of the TP53 family with high structural homology to p53 and capable of transactivating p53 target genes. The TP73 gene locus which is highly conserved and complex, encodes for two classes of isoforms TAp73 (tumor suppressor isoforms containing the transactivation domain) and ΔNp73 (oncogenic isoforms, truncated and lacking the transactivation domain) with opposing effects. The balance between TAp73 and ΔNp73 isoforms and their harmony with other members of the TP73 family regulate various cellular responses such as apoptosis, autophagy, proliferation, and differentiation. The transcriptionally active isoforms of p73 are capable of inducing apoptosis in cancer cells independent of p53 status. Unlike p53, p73 is rarely mutated in cancers, however, the ratio of ΔNp73:TAp73 is frequently up-regulated in many carcinomas and is indicative of poor prognosis. Moreover, p73 is an important determinant of chemosensitivity and radiosensitivity, the two major treatment modalities for lymphoma. In the current review, we will provide an overview of recent progress discussing the role of TP73 in cancer, specifically addressing its relevance to lymphomagenesis, progression, therapy resistance, and its potential as a novel therapeutic target.

Unc45b is essential for early myofibrillogenesis and costamere formation in zebrafish.

Despite the prevalence of developmental myopathies resulting from muscle fiber defects, the earliest stages of myogenesis remain poorly understood. Unc45b is a molecular chaperone that mediates the folding of thick-filament myosin during sarcomere formation; however, Unc45b may also mediate specific functions of non-muscle myosins (NMMs). unc45b Mutants have specific defects in striated muscle development, which include myocyte detachment indicative of dysfunctional adhesion complex formation. Given the necessity for non-muscle myosin function in the formation of adhesion complexes and premyofibril templates, we tested the hypothesis that the unc45b mutant phenotype is not mediated solely by interaction with muscle myosin heavy chain (mMHC). We used the advantages of a transparent zebrafish embryo to determine the temporal and spatial patterns of expression for unc45b, non-muscle myosins and mMHC in developing somites. We also examined the formation of myocyte attachment complexes (costameres) in wild-type and unc45b mutant embryos. Our results demonstrate co-expression and co-regulation of Unc45b and NMM in myogenic tissue several hours before any muscle myosin heavy chain is expressed. We also note deficiencies in the localization of costamere components and NMM in unc45b mutants that is consistent with an NMM-mediated role for Unc45b during early myogenesis. This represents a novel role for Unc45b in the earliest stages of muscle development that is independent of muscle mMHC folding.