The BALB/c.mdx62 mouse exhibits a dystrophic muscle pathology and is a model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a devastating monogenic skeletal muscle-wasting disorder. Although many pharmacological and genetic interventions have been reported in preclinical studies, few have progressed to clinical trials with meaningful benefit. Identifying therapeutic potential can be limited by availability of suitable preclinical mouse models. More rigorous testing across models with varied background strains and mutations can identify treatments for clinical success. Here, we report the generation of a DMD mouse model with a CRISPR-induced deletion within exon 62 of the dystrophin gene (Dmd) and the first generated in BALB/c mice. Analysis of mice at 3, 6 and 12 months of age confirmed loss of expression of the dystrophin protein isoform Dp427 and resultant dystrophic pathology in limb muscles and the diaphragm, with evidence of centrally nucleated fibers, increased inflammatory markers and fibrosis, progressive decline in muscle function, and compromised trabecular bone development. The BALB/c.mdx62 mouse is a novel model of DMD with associated variations in the immune response and muscle phenotype, compared with those of existing models. It represents an important addition to the preclinical model toolbox for developing therapeutic strategies.

Patient perceptions of three-dimensional (3D) surface imaging technology and traditional methods used to assess anthropometry.

Background: Obesity and overweight are commonplace, yet attrition rates in weight management clinics are high. Traditional methods of body measurement may be a deterrent due to invasive and time-consuming measurements and negative experiences of how data are presented back to individuals. Emerging new technologies, such as three-dimensional (3D) surface imaging technology, might provide a suitable alternative. This study aimed to understand acceptability of traditional and 3D surface imaging-based body measures, and whether perceptions differ between population groups. Methods: This study used a questionnaire to explore body image, body measurement and shape, followed by a qualitative semi-structured interview and first-hand experience of traditional and 3D surface imaging-based body measures. Results: 49 participants responded to the questionnaire and 26 participants attended for the body measurements and interview over a 2-month period. There were 3 main themes from the qualitative data 1) Use of technology, 2) Participant experience, expectations and perceptions and 3) Perceived benefits and uses. Conclusion: From this study, 3D-surface imaging appeared to be acceptable to patients as a method for anthropometric measurements, which may reduce anxiety and improve attrition rates in some populations. Further work is required to understand the scalability, and the role and implications of these technologies in weight management practice. (University Research Ethics Committee reference number ER41719941).

Identifying Key Themes of Care Coordination for Patients with Chronic Conditions in Singapore: A Scoping Review.

A projected rise in patients with complex health needs and a rapidly ageing population will place an increased burden on the healthcare system. Care coordination can bridge potential gaps during care transitions and across the care continuum to facilitate care integration and the delivery of personalised care. Despite having a national strategic vision of improving care integration across different levels of care and community partners, there is no consolidation of evidence specifically on the salient dimensions of care coordination in the Singapore healthcare context. Hence, this scoping review aims to uncover the key themes that facilitate care coordination for patients with chronic conditions in Singapore to be managed in the community while illuminating under-researched areas in care coordination requiring further exploration. The databases searched were PubMed, CINAHL, Scopus, Embase, and Cochrane Library. Results from Google Scholar were also included. Two independent reviewers screened articles in a two-stage screening process based on the Cochrane scoping review guidelines. Recommendation for inclusion was indicated on a three-point scale and rating conflicts were resolved through discussion. Of the 5792 articles identified, 28 were included in the final review. Key cross-cutting themes such as having standards and guidelines for care programmes, forging stronger partnerships across providers, an interoperable information system across care interfaces, strong programme leadership, financial and technical resource availabilities and patient and provider-specific factors emerged. This review also recommends leveraging these themes to align with Singapore's national healthcare vision to contain rising healthcare costs.

Increasing muscle contractility through low-frequency stimulation alters tibial bone geometry and reduces bone strength in mdx and dko dystrophic mice.

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by mutations or deletions in the dystrophin gene, for which there remains no cure. As DMD patients also develop bone fragility because of muscle weakness and immobilization, better understanding of the pathophysiological mechanisms of dystrophin deficiency will help develop therapies to improve musculoskeletal health. Since alterations in muscle phenotype can influence bone structure, we investigated whether modifying muscle contractile activity through low-frequency stimulation (LFS) could alter bone architecture in mouse models of DMD. We tested the hypothesis that increasing muscle contractile activity could influence bone mass and structure in dystrophin-deficient (mdx) and dystrophin- and utrophin-deficient (dko) dystrophic mice. Tibial bone structure in dko mice was significantly different from that in mdx and wild-type (C57BL/10) control mice. Effects of LFS on bone architecture differed between dystrophic and healthy mice, with LFS thinning cortical bone in both dystrophic models. Bone mass was maintained in LFS-treated healthy mice, with a reduced proportion of high-density bone and concomitant increase in low-density bone. LFS-treated dko mice exhibited a net deficit in cortical thickness and reduced high-density bone but no equivalent increase in low-density bone. These alterations in bone structure and mineral density reduced mechanical strength in mdx and dko mice. The findings reveal that muscle activity can regulate bone mass, structure, mineral accrual, and strength, especially in the context of dystrophin and/or utrophin deficiency. The results provide unique insights into the development of bone fragility in DMD and for devising interventions to improve musculoskeletal health.NEW & NOTEWORTHY Patients with Duchenne muscular dystrophy (DMD) develop bone fragility because of muscle weakness and immobilization. We investigated whether increasing muscle contractile activity through low-frequency stimulation (LFS) could alter bone architecture in dystrophin-deficient (mdx) or dystrophin- and utrophin-deficient (dko) mouse models of DMD. Chronic LFS reduced tibial diaphysis cross sections in mdx and dko mice, without affecting bone shape in healthy mice. LFS affected the distribution of bone mineral density across all phenotypes, with the magnitude of effect being dependent on disease severity.

Qualitative study exploring heterogeneity in caregiving experiences post-stroke in Singapore.

OBJECTIVE: Stroke, a common illness in older adults, accounts for up to 4% of direct medical costs in developed nations. Informal caregiving contributing a significant proportion of economic burden post-stroke warrants a deeper understanding of the caregiving context to sustain caregiving arrangement. While literature exists describing differences in motivation and preferences of caregivers, limited literature explores differences in caregiving experiences of different types of caregivers (ie, spouse, adult-child, sibling or others). Addressing this gap, our study aimed to explore the caregiving experience of stroke survivors and their family caregivers across different caregiver identities in an Asian setting. DESIGN: Qualitative descriptive study. SETTING: Community setting. PARTICIPANTS: We conducted semi-structured interviews with 26 stroke survivors and 35 caregivers purposively sampled from an outpatient rehabilitation setting, an outpatient clinic and a support organisation. Data were analysed using thematic analysis. OUTCOME MEASURES: Themes including caregiving experience of stroke survivors and their family caregivers across different caregiver identities. RESULTS: Following five themes were reported: caregiver reserve, coping strategies, caregiver burden, competing commitments and role of foreign domestic worker (FDW) in family caregiving. Spouse caregivers were less willing to ask for help, commonly adopted faith-based, and spacing or recharging types of coping, reported emotional strain and shared limited accounts of FDWs. Adult-child caregivers were more willing to ask for help, engaged in alternative care arrangements involving FDWs, commonly adopted action-focussed coping and reported multidimensional caregiver burden. CONCLUSION: Our findings illustrated the heterogeneity in factors affecting caregiving experience across spouse and adult-child caregivers. Practical implications include conducting a needs assessment for caregiver-stroke survivor dyads and providing tailored support, training and information to help caregivers cope better.

STAT3 Hyperactivation Due to SOCS3 Deletion in Murine Osteocytes Accentuates Responses to Exercise- and Load-Induced Bone Formation.

Cortical bone develops and changes in response to mechanical load, which is sensed by bone-embedded osteocytes. The bone formation response to load depends on STAT3 intracellular signals, which are upregulated after loading and are subject to negative feedback from Suppressor of Cytokine Signaling 3 (Socs3). Mice with Dmp1Cre-targeted knockout of Socs3 have elevated STAT3 signaling in osteocytes and display delayed cortical bone maturation characterized by impaired accrual of high-density lamellar bone. This study aimed to determine whether these mice exhibit an altered response to mechanical load. The approach used was to test both treadmill running and tibial compression in female Dmp1Cre.Socs3f/f mice. Treadmill running for 5 days per week from 6 to 11 weeks of age did not change cortical bone mass in control mice, but further delayed cortical bone maturation in Dmp1Cre.Socs3f/f mice; accrual of high-density bone was suppressed, and cortical thickness was less than in genetically-matched sedentary controls. When strain-matched anabolic tibial loading was tested, both control and Dmp1Cre.Socs3f/f mice exhibited a significantly greater cortical thickness and periosteal perimeter in loaded tibia compared with the contralateral non-loaded bone. At the site of greatest compressive strain, the loaded Dmp1Cre.Socs3f/f tibias showed a significantly greater response than controls, indicated by a greater increase in cortical thickness. This was due to a greater bone formation response on both periosteal and endocortical surfaces, including formation of abundant woven bone on the periosteum. This suggests a greater sensitivity to mechanical load in Dmp1Cre.Socs3f/f bone. In summary, mice with targeted SOCS3 deletion and immature cortical bone have an exaggerated response to both physiological and experimental mechanical loads. We conclude that there is an optimal level of osteocytic response to mechanical load required for cortical bone maturation and that load-induced bone formation may be increased by augmenting STAT3 signaling within osteocytes. © 2021 American Society for Bone and Mineral Research (ASBMR).

Investigating the Potential for Sulforaphane to Attenuate Gastrointestinal Dysfunction in mdx Dystrophic Mice.

Gastrointestinal (GI) dysfunction is an important, yet understudied condition associated with Duchenne muscular dystrophy (DMD), with patients reporting bloating, diarrhea, and general discomfort, contributing to a reduced quality of life. In the mdx mouse, the most commonly used mouse model of DMD, studies have confirmed GI dysfunction (reported as altered contractility and GI transit through the small and large intestine), associated with increased local and systemic inflammation. Sulforaphane (SFN) is a natural isothiocyanate with anti-inflammatory and anti-oxidative properties via its activation of Nrf2 signalling that has been shown to improve aspects of the skeletal muscle pathology in dystrophic mice. Whether SFN can similarly improve GI function in muscular dystrophy was unknown. Video imaging and spatiotemporal mapping to assess gastrointestinal contractions in isolated colon preparations from mdx and C57BL/10 mice revealed that SFN reduced contraction frequency when administered ex vivo, demonstrating its therapeutic potential to improve GI function in DMD. To confirm this in vivo, four-week-old male C57BL/10 and mdx mice received vehicle (2% DMSO/corn oil) or SFN (2 mg/kg in 2% DMSO/corn oil) via daily oral gavage five days/week for 4 weeks. SFN administration reduced fibrosis in the diaphragm of mdx mice but did not affect other pathological markers. Gene and protein analysis revealed no change in Nrf2 protein expression or activation of Nrf2 signalling after SFN administration and oral SFN supplementation did not improve GI function in mdx mice. Although ex vivo studies demonstrate SFN's therapeutic potential for reducing colon contractions, in vivo studies should investigate higher doses and/or alternate routes of administration to confirm SFN's potential to improve GI function in DMD.

Seeking healthcare services post-stroke: a qualitative descriptive study exploring family caregiver and stroke survivor perspectives in an asian setting.

AIM: Exploration of the healthcare journey post-stroke is incomplete without acknowledging the crucial role of family caregivers. With limited literature documenting the role of caregivers in the healthcare journey post-stroke, we aimed to describe the healthcare experiences of family caregivers and stroke survivors across different caregiver identities in Singapore. METHODS: We conducted a qualitative descriptive study involving semi-structured interviews with transcripts analysed using thematic analysis. 26 stroke survivors and 35 family caregivers purposively sampled from multiple settings. RESULTS: Findings were summarized into seeking care and experience of healthcare encounters. Seeking care comprised of the following themes: factors influencing seeking care, decision to seek care and role of caregiver in seeking care. Experience of healthcare encounters comprised of the following themes: service around the patient, service with care and role of caregiver in healthcare encounters. CONCLUSION: Multi-dimensional role of caregivers in healthcare experience emerged as a major finding. Unique to our Asian context, as per the participants' accounts, family caregivers seemed to be central in healthcare decision-making for stroke survivors, with adult-child caregivers commonly reported being engaged in collaborative decision-making. While spousal caregivers preferred a relational healthcare experience, adult-child caregivers preferred a transactional one. Practical implications include equipping caregivers with skillset to make healthcare decisions, provision of supportive decision-making environment for caregivers and reinforcing communication aspects in the medical, nursing and allied healthcare curriculum to improve healthcare experience.

Comprehensive characterization of single-cell full-length isoforms in human and mouse with long-read sequencing.

A modified Chromium 10x droplet-based protocol that subsamples cells for both short-read and long-read (nanopore) sequencing together with a new computational pipeline (FLAMES) is developed to enable isoform discovery, splicing analysis, and mutation detection in single cells. We identify thousands of unannotated isoforms and find conserved functional modules that are enriched for alternative transcript usage in different cell types and species, including ribosome biogenesis and mRNA splicing. Analysis at the transcript level allows data integration with scATAC-seq on individual promoters, improved correlation with protein expression data, and linked mutations known to confer drug resistance to transcriptome heterogeneity.

Support system diversity among family caregivers of stroke survivors: a qualitative study exploring Asian perspectives.

BACKGROUND: Caregiving is a global phenomenon which is bound to increase in tandem with the aging population worldwide. Stroke is a condition common in older people that requires complex caregiving necessitating provision of adequate support to the caregivers. Past literature consists of limited accounts of types and organization of support arrangements needed by different caregivers. We aimed to describe the support system of caregivers of stroke survivors in Singapore, highlighting differences across the different caregiver identities (i.e. spouse, adult-child, etc.). METHODS: We conducted a qualitative descriptive study in the community setting involving 61 purposively sampled and recruited stroke survivors and caregivers. Semi-structured interviews were conducted, and transcripts were analysed using thematic analysis. RESULTS: Our findings were summarized across the following 4 themes: 1) cultural influence and caregiving; 2) caregiver support system with the following sub-themes: 2.1) dyadic caregiver support type, 2.2) extended caregiver support type, 2.3.) distributed caregiver support type and 2.4) empowering caregiver support type; 3) breaks in care of stroke survivor and 4) complex relationship dynamics. We operationalized the caregiver support system as comprising of type, people and activities that enable the caregiver to participate in caregiving activities sustainably. While spouse caregivers preferred dyadic and extended support systems positioning themselves in a more central caregiving role, adult-child caregivers preferred distributed support system involving family members with paid caregivers playing a more central role. CONCLUSIONS: Our findings highlight caregiver identity as a surrogate for the differences in the caregiver support systems. Practical implications include imparting relationship-building skills to the stroke survivor-caregiver dyads to sustain dyadic support system and educating clinicians to include differences in caregiving arrangements of stroke survivors in practising family-centred care.

Dystrophin deficiency disrupts muscle clock expression and mitochondrial quality control in mdx mice.

Impaired oxidative capacity and mitochondrial function contribute to the dystrophic pathology in muscles of patients with Duchenne muscular dystrophy (DMD) and in relevant mouse models of the disease. Emerging evidence suggests an association between disrupted core clock expression and mitochondrial quality control, but this has not been established in muscles lacking dystrophin. We examined the diurnal regulation of muscle core clock and mitochondrial quality control expression in dystrophin-deficient C57BL/10ScSn-Dmdmdx (mdx) mice, an established model of DMD. Male C57BL/10 (BL/10; n = 18) and mdx mice (n = 18) were examined every 4 h beginning at the dark cycle. Throughout the entire light-dark cycle, extensor digitorum longus (EDL) muscles from mdx mice had decreased core clock mRNA expression (Arntl, Cry1, Cry2, Nr1d2; P < 0.05) and disrupted mitochondrial quality control mRNA expression related to biogenesis (decreased; Ppargc1a, Esrra; P < 0.05), fission (increased; Dnm1l; P < 0.01), fusion (decreased; Opa1, Mfn1; P < 0.05), and autophagy/mitophagy (decreased: Bnip3; P < 0.05; increased: Becn1; P < 0.05). Cosinor analysis revealed a decrease in the rhythmicity parameters mesor and amplitude for Arntl, Cry1, Cry2, Per2, and Nr1d1 (P < 0.001) in mdx mice. Diurnal oscillations in Esrra, Sirt1, Map1lc3b, and Sqstm1 were absent in mdx mice, along with decreased mesor and amplitude of Ppargc1a mRNA expression (P < 0.01). The expression of proteins involved in mitochondrial biogenesis (decreased: PPARGC1A, P < 0.05) and autophagy/mitophagy (increased: MAP1LC3BII, SQSTM1, BNIP3; P < 0.05) were also dysregulated in tibialis anterior muscles of mdx mice. These findings suggest that dystrophin deficiency in mdx mice impairs the regulation of the core clock and mitochondrial quality control, with relevance to DMD and related disorders.

Bone Geometry Is Altered by Follistatin-Induced Muscle Growth in Young Adult Male Mice.

The development of the musculoskeletal system and its maintenance depends on the reciprocal relationship between muscle and bone. The size of skeletal muscles and the forces generated during muscle contraction are potent sources of mechanical stress on the developing skeleton, and they shape bone structure during growth. This is particularly evident in hypermuscular global myostatin (Mstn)-null mice, where larger muscles during development increase bone mass and alter bone shape. However, whether muscle hypertrophy can similarly influence the shape of bones after the embryonic and prepubertal period is unknown. To address this issue, bone structure was assessed after inducing muscle hypertrophy in the lower hindlimbs of young-adult C57BL/6J male mice by administering intramuscular injections of recombinant adeno-associated viral vectors expressing follistatin (FST), a potent antagonist of Mstn. Two FST isoforms were used: the full-length 315 amino acid isoform (FST-315) and a truncated 288 amino acid isoform (FST-288). In both FST-treated cohorts, muscle hypertrophy was observed, and the anterior crest of the tibia, adjacent to the tibialis anterior muscle, was lengthened. Hypertrophy of the muscles surrounding the tibia caused the adjacent cortical shell to recede inward toward the central axis: an event driven by bone resorption adjacent to the hypertrophic muscle. The findings reveal that inducing muscle hypertrophy in mice can confer changes in bone shape in early adulthood. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Measuring Bone Volume at Multiple Densities by Micro-computed Tomography.

Bone strength is controlled by both bone mass, and the organization and quality of the bone material. The current standard method for measuring bone mass in mouse and rat studies is micro-computed tomography. This method typically uses a single threshold to identify bone material in the cortical and trabecular regions. However, this single threshold method obscures information about the mineral content of the bone material and depends on normal morphology to separately analyze cortical and trabecular structures. To extend this method to identify bone mass at multiple density levels, we have established a protocol for unbiased selection and application of multiple thresholds using a standard laboratory-based micro-computed tomography instrument. This non-invasive method can be applied to longitudinal studies and archived samples and provides additional information about bone structure and strength.

Diagnostic and treatment challenges of a case of primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid.

BACKGROUND: Primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid is an extremely rare but aggressive neoplasm diagnosed primarily in elderly men. Until now there are 32 published cases of signet-ring cell carcinoma or histiocytoid carcinoma of the eyelid. We report the clinical, radiographic and histological features of the 33rd reported case of PCSRCC in the eyelid of a 73-year-old male, and review diagnostic and treatment challenges of this rare entity. CASE PRESENTATION: Our case highlights a 73-year-old male who was referred for surgical correction of right eye ptosis that was present for 2 years. Upon assessment, he was noted to have an upper lateral orbital rim mass. Computed tomography (CT) noted ill-defined soft tissue thickening anterior to the right globe, predominantly pre-septal but with slight post-septal extension. The pathology revealed diffusely and deeply infiltrating tumour cells extending through the dermis, subcutis, orbicularis muscle bundles and nerve fibers; the tumour cells were noted to have a monotonous histiocytoid appearance with foamy granular eosinophilic cytoplasm. At high magnification, intracytoplasmic vacuoles and occasional intermixed signet ring cells were identified. Immunohistochemical staining revealed the tumour cells to be AE1/AE3, CK7, GCDFP-15, E-cadherin, androgen receptor stain and GATA3 positive. Final pathology report confirmed the diagnosis of primary cutaneous signet-ring cell/histiocytoid carcinoma. Further imaging failed to identify a distant primary malignancy or metastatic disease. The decision was made to attempt surgical excision of the tumor. After the bulk of the grossly apparent tumor was removed, intraoperative frozen sections were sent. Superficial biopsies of the right periorbital region were performed, which revealed extension significantly further than the gross disease. Thereafter, the patient underwent a wide orbital exenteration with reconstruction using a temporary split-thickness skin graft. Due to positive margins on final permanent sections, the patient underwent further wide resection with free muscle-skin flap reconstruction followed by adjuvant radiation treatment. CONCLUSION: Our case represents the 33rd case of primary signet-ring cell/histiocytoid carcinoma of the eyelid in a 73-year-old male, the first documented case with GATA3 positivity and the second documented case with androgen receptor stain positivity.

Chronic Ulcers and Malnutrition in an African Patient.

An 11-year-old girl with a congenitally malformed left hand, sickle cell trait, asthma, and history of appendicitis was transferred from Zambia for evaluation and treatment of widespread suppurative and ulcerative skin lesions that typically appeared after trauma to her skin. The ulcers first presented 3 years earlier but had markedly worsened in the 9 months before transfer, spreading circumferentially on her extremities and abdomen at the site of an appendectomy. They were painful and did not resolve with multiple courses of intravenous antibiotics and close management by a pediatric infectious disease specialist working for a nongovernmental organization (NGO) in her home country. Per NGO records, she had previously been  average weight-for-age. On presentation after international transfer, she was severely malnourished, with lesions covering âˆ¼35% of her body. In initial workup, leukocytosis of 21 × 103 cells per µL (79% neutrophils), hemoglobin of 6.1 g/dL, and mean corpuscular volume of 66 fL were found. Iron studies revealed an iron level of 18 µg/dL, ferritin level of 55 ng/mL, total iron binding capacity of 222 µg/dL, and transferrin saturation of 8%. Inflammatory markers were elevated, C-reactive protein was 20.1 mg/dL, and the erythrocyte sedimentation rate was 131 mm/h. A chest computed tomography scan revealed bilateral pulmonary nodules, the largest in her left upper lobe measuring 2.4 × 2.0 × 1.9 cm. Our panel of experts reviews the evaluation and treatment of this patient with extensive suppurative and ulcerative skin lesions and the factors considered in offering charity care to international patients.

Necrobiosis lipoidica with rapid response to doxycycline.

Necrobiosis lipoidica (NL) is a rare granulomatous disease of unknown etiology. Multiple therapies may be used with varying efficacy. We report a pediatric patient with a history of type I diabetes mellitus and NL with minimal response to an ultrapotent topical steroid, topical calcineurin inhibitor, and intralesional triamcinolone, complicated by steroid atrophy, who rapidly responded after addition of doxycycline.