Heterozygous variants in MYH10 associated with neurodevelopmental disorders and congenital anomalies with evidence for primary cilia-dependent defects in Hedgehog signaling.

PURPOSE: Nonmuscle myosin II complexes are master regulators of actin dynamics that play essential roles during embryogenesis with vertebrates possessing 3 nonmuscle myosin II heavy chain genes, MYH9, MYH10, and MYH14. As opposed to MYH9 and MYH14, no recognizable disorder has been associated with MYH10. We sought to define the clinical characteristics and molecular mechanism of a novel autosomal dominant disorder related to MYH10. METHODS: An international collaboration identified the patient cohort. CAS9-mediated knockout cell models were used to explore the mechanism of disease pathogenesis. RESULTS: We identified a cohort of 16 individuals with heterozygous MYH10 variants presenting with a broad spectrum of neurodevelopmental disorders and variable congenital anomalies that affect most organ systems and were recapitulated in animal models of altered MYH10 activity. Variants were typically de novo missense changes with clustering observed in the motor domain. MYH10 knockout cells showed defects in primary ciliogenesis and reduced ciliary length with impaired Hedgehog signaling. MYH10 variant overexpression produced a dominant-negative effect on ciliary length. CONCLUSION: These data presented a novel genetic cause of isolated and syndromic neurodevelopmental disorders related to heterozygous variants in the MYH10 gene with implications for disrupted primary cilia length control and altered Hedgehog signaling in disease pathogenesis.

An assessment of early Child Life Therapy pain and anxiety management: A prospective randomised controlled trial.

INTRODUCTION: Burns remain extremely painful and distressing in young children. The consequences of poorly managed pain and anxiety can be life-long. Whilst Child Life Therapy (CLT) has been shown to be effective in many situations, few studies have looked at the effectiveness of CLT in regard to reducing pain and anxiety in children undergoing burn dressing changes. METHODS: A prospective, randomised controlled trial was conducted, comparing CLT versus standard care in relation to pain and anxiety scores of children undergoing their initial burn dressing change. Pain and anxiety were assessed by an independent observer and questionnaires completed by the child, parent/caregiver and nursing staff. RESULTS: 50 subjects were recruited in each treatment group; median age 2.3 years (CLT) and 2.2 years (standard care). The median total body surface area (TBSA) burnt was 0.8% (CLT) and 0.5% (standard care). The majority were partial thickness dermal burns (88% CLT, 94% standard care). Rates of parent anxiety and pre-procedural child pain and anxiety were similar. Combined and scaled pain and anxiety scores in the CLT group were significantly less than in the standard treatment group (p=0.03). Whilst pain was significantly better in the CLT group (p=0.02), fear scores, wound outcomes and the need for skin grafting were not statistically different in either group. CONCLUSIONS: The presence of a Child Life Therapist, with their ability to adapt to the environment, the child and their family, significantly reduced the experience of pain during paediatric burn dressings.

Diagnosis of ecto- and endoparasites in laboratory rats and mice.

Internal and external parasites remain a significant concern in laboratory rodent facilities, and many research facilities harbor some parasitized animals. Before embarking on an examination of animals for parasites, two things should be considered. One: what use will be made of the information collected, and two: which test is the most appropriate. Knowing that animals are parasitized may be something that the facility accepts, but there is often a need to treat animals and then to determine the efficacy of treatment. Parasites may be detected in animals through various techniques, including samples taken from live or euthanized animals. Historically, the tests with the greatest diagnostic sensitivity required euthanasia of the animal, although PCR has allowed high-sensitivity testing for several types of parasite. This article demonstrates procedures for the detection of endo- and ectoparasites in mice and rats. The same procedures are applicable to other rodents, although the species of parasites found will differ.

Diagnostic necropsy and selected tissue and sample collection in rats and mice.

There are multiple sample types that may be collected from a euthanized animal in order to help diagnose or discover infectious agents in an animal colony. Proper collection of tissues for further histological processing can impact the quality of testing results. This article describes the conduct of a basic gross examination including identification of heart, liver, lungs, kidneys, and spleen, as well as how to collect those organs. Additionally four of the more difficult tissue/sample collection techniques are demonstrated. Lung collection and perfusion can be particularly challenging as the tissue needs to be properly inflated with a fixative in order for inside of the tissue to fix properly and to enable thorough histologic evaluation. This article demonstrates the step by step technique to remove the lung and inflate it with fixative in order to achieve optimal fixation of the tissue within 24 hours. Brain collection can be similarly challenging as the tissue is soft and easily damaged. This article demonstrates the step by step technique to expose and remove the brain from the skull with minimal damage to the tissue. The mesenteric lymph node is a good sample type in which to detect many common infectious agents as enteric viruses persist longer in the lymph node than they are shed in feces. This article demonstrates the step by step procedure for locating and aseptically removing the mesenteric lymph node. Finally, identification of infectious agents of the respiratory tract may be performed by bacterial culture or PCR testing of nasal and/or bronchial fluid aspirates taken at necropsy. This procedure describes obtaining and preparing the respiratory aspirate sample for bacterial culture and PCR testing.