Microvillus inclusion disease: a case report and literature review / 中华围产医学杂志

Objective:To investigate the clinical features and genetic mutations of microvillus inclusion disease (MVID).Methods:Clinical features and gene sequencing results of a neonate with MVID in Children's Hospital of Chongqing Medical University in August 2019 were retrospectively analyzed. Literature was retrieved up to October 2021, with the terms of microvillus inclusion disease, congenital microvilli atrophy, MVID, MYO5B, STX3, and STXBP2 in China National Knowledge Infrastructure, Wanfang Database, VIP database, and PubMed. Clinical features, diagnosis, and treatment of the reported MVID cases were reviewed. Results:(1) Case report: A male infant presented with jaundice two days after birth and was admitted to our hospital. Clinical features included intractable diarrhea, intermittent abdominal distension, uncorrectable dehydration, and weight loss. Laboratory test results indicated metabolic acidosis, electrolyte disorder, and cholestasis. Whole exome sequencing confirmed the diagnosis of MVID in this baby boy with compound heterozygous mutations of c.1021C>T(p.Q341*) and c.1125G>A(p.W375*) in the MYO5B gene, which were inherited from the father and the mother, respectively. (2) Literature review: Except for the present case, 31 patients from 20 articles were reviewed, and the typical clinical manifestations were intractable diarrhea, accompanied by dehydration, metabolic acidosis, electrolyte disorder, etc. Some patients also developed extra-gastrointestinal symptoms, including feeding difficulties and malnutrition (8/18), respiratory distress syndrome (4/18) and jaundice/cholestasis (4/18) in patients with MYO5B mutations; feeding difficulties and malnutrition (2/5), respiratory distress syndrome (1/5), and sepsis (1/5) in patients with STX3 mutations; feeding difficulties (2/9), respiratory distress syndrome (1/9), jaundice/cholestasis (1/9), sepsis (1/9), and hypoglycemia (1/9) in patients with STXBP2 mutations. In terms of the demographic data and prenatal examination, preterm birth (8/18), fetal bowel dilatation (5/18), polyhydramnios (5/18), parental consanguinity (2/18), and meconium-stained amniotic fluid (2/18) occurred among patients with MYO5B mutations. In those with STX3 mutations, parental consanguinity (3/5), fetal bowel dilatation (1/5), polyhydramnios (1/5), and meconium-stained amniotic fluid (1/5) occurred. Of nine patients with STXBP2 mutations, parental consanguinity (3/9), preterm birth (2/9), and polyhydramnios (2/9) occurred. Conclusions:MVID has atypical clinical features and a high mortality, resulting in difficulty in the diagnosis and treatment. The possibility of MVID should be considered when an infant presents with intractable diarrhea, dehydration, metabolic acidosis, and electrolyte disorder accompanied by multiple extra-gastrointestinal symptoms. Early identification of MYO5B, STX3, and STXBP2 mutations will benefit prompt intervention, prognosis evaluation, and genetic counseling.

Plasticidad muscular y fibras híbridas en la musculatura masticatoria: revisión de literatura / Muscle plasticity and hybrid fibers in the masticatory musculature: literature review

La musculatura masticatoria se caracteriza por presentar fibras híbridas que en los últimos años se han relacionado con el fenómeno de plasticidad muscular. El objetivo del estudio fue describir la relación entre la plasticidad muscular y las fibras musculares híbridas presentes en la musculatura masticatoria, mediante una revisión narrativa de literatura. Para esto, se realizó una búsqueda electrónica en PUBMED, ScienceDirect y BIREME, utilizando las palabras claves: "Muscle Plasticity", "Hybrid Muscle Fibers" y "Hybrid Fibers". Fueron seleccionados documentos que reportan las isoformas de cadena pesada de miosina (MHC) presentes en los músculos masticatorios de humanos y otros mamíferos, junto a los cambios vinculados a demandas funcionales. Se describe la presencia de fibras puras tipo I y tipo II, además de otras isoformas como la MHC-la, MHC-IIM, MHC-fetal y MHC-cardíaca. Sin embargo, un porcentaje considerable de fibras en la musculatura masticatoria son híbridas, es decir, expresan a más de una isoforma de MHC, las cuales también son diferentes a nivel intermuscular e intramuscular. Las influencias locales pueden contribuir a la variación de la expresión del tipo de fibra. En la musculatura masticatoria, el destete, la dureza de los alimentos, el bruxismo, la morfología craneofacial y el uso de prótesis dentales genera cambios a nivel de los músculos masticatorios, donde es común la presencia de fibras híbridas. Se concluye la presencia importante de fibras híbridas en la musculatura masticatoria y su relación con la plasticidad muscular a lo largo del ciclo vital, debido a cambios funcionales y patológicos. Es importante que los terapeutas de habla y motricidad orofacial profundicen en el conocimiento de la fisiología del comportamiento oromiofuncional.

The masticatory musculature is characterized by presenting hybrid fibers that in recent years have been related to the phenomenon of muscle plasticity. The objective of the study was to describe the relationship between muscle plasticity and the hybrid muscle fibers present in the masticatory muscles, through a narrative review. For this, an electronic search was conducted in PUBMED, ScienceDirect and BIREME, using the keywords: "Muscle Plasticity", "Hybrid Muscle Fibers" and "Hybrid Fibers". Documents that report the myosin heavy chain (MHC) isoforms present in the masticatory muscles of humans and other mammals were selected, along with the changes linked to functional demands. The presence of type I and type II pure fibers were described, in addition to other isoforms such as MHC-la, MHC-IIM, MHC-fetal and MHC-cardiac. However, a significant percentage of fibers in the masticatory muscles are hybrids, that is, they express more than one MHC isoform, which are also different at the intermuscular and intramuscular level. Local influences can contribute to the variation of fiber type expression. In the chewing muscles, weaning, the hardness of food, bruxism, craniofacial morphology and the use of dental prostheses generate changes at the level of the chewing muscles, where the presence of hybrid fibers is common. The important presence of hybrid fibers in the masticatory muscles and their relationship with muscle plasticity throughout the life cycle, due to functional and pathological changes, is concluded. It is important for Speech Therapy andMyofunctional Therapy to deepen their understanding of the physiology of oromyofunctional behavior.

Cardiac Myosin Heavy Chains

Myosin is defined as a mechano-enzyme molecule which converts the chemical energy stored as adenosine triphosphate (ATP) into mechanical energy (muscle contraction). Moreover, the cardiac muscle has different types of myosin heavy chain when it separated with the one dimensional electrophoresis; in addition to their structural difference cardiac myosin isozymes have different contractile functions.

Gene screening and phenotype analysis in a pedigree with familial hypertrophic cardiomyopathy from Yunnan Province / 中华心血管病杂志

Objective@#To identify the disease-causing mutations in a pedigree with familial hypertrophic cardiomyopathy (HCM) from Yunnan province, and analyze the relationship between the genotype and the phenotype.@*Methods@#The blood samples and the clinical data of the HCM family members were collected.The coding exons and their flanking intronic regions of 28 previously reported genes related to HCM were screened in the proband by high-throughput sequencing. The mutations in proband were confirmed and detected in all family members as well as in 159 healthy controls by Sanger sequencing.The relationship between the genotype and the phenotype was analyzed in this pedigree.@*Results@#Two missense mutations of Arg1045His and Ala26Val in β myosin heavy chain gene(MYH7) were identified. Genetic screening showed that the mother and brother of the proband carried Arg1045His mutation.Both mutations were absent in other family members and in 159 healthy controls.Disease onset age was less than 50 years old in this pedigree, chest pain, exertional dyspnea and syncope were the major symptoms, and all accompanied by severe left ventricular hypertrophy and left ventricular outflow tract stenosis.The grandma of the proband suffered sudden cardiac death. The proband had the worst symptoms and the earliest disease onset in this pedigree.@*Conclusions@#We find a pedigree with familial HCM from Yunnan province carrying MYH7 Arg1045His and Ala26Val mutations. The study suggests that Arg1045His mutation in MYH7 gene caused HCM is malignant with early onset, severe ventricular hypertrophy and poor prognosis. Arg1045His and Ala26Val double-mutant might have dosage effects and aggravate the clinical phenotype of the patient.

Enzymatic dissociation of long muscles from mice: a model for the study of skeletal muscle fiber types / Disociación enzimática de músculos largos de ratón: un modelo para el estudio de los tipos de fibras del músculo esquelético

The enzymatic dissociation of short muscles from mice, such as flexor digitorum brevis, has allowed a great accumulation of physiological, pharmacological and biochemical knowledge about skeletal muscle. However, this body of knowledge has been restricted to the types of fibers present in these muscles. Information about the other fiber types has been limited and has been primarily obtained by the manual isolation of fibers from other species, typically rats, via a difficult and time-consuming procedure. In this report, the author describes a technique for the enzymatic dissociation of long muscles, such as soleus or extensor digitorum longus (EDL), which can be applied to study a wider spectrum of fiber types and larger quantities of cells. Additionally, the kinetics of Ca2+ transients obtained in soleus and EDL fibers are compared in this report. The usefulness of this methodology for other physiological, biochemical and molecular biology experiments is also discussed. This methodology introduces the possibility of using the whole spectrum of fiber types to study normal muscle biology and the pathophysiology of muscle diseases.

La disociación enzimática de músculos cortos de ratón, como el flexor digitorum brevis, ha permitido la acumulación de gran cantidad de información fisiológica, farmacológica y bioquímica sobre el músculo esquelético, la cual, sin embargo, ha estado limitada a los tipos de fibras presentes en estos músculos. La acumulación de información sobre los demás tipos de fibras ha sido escasa y se ha logrado mediante el aislamiento manual de fibras en otras especies, clásicamente en ratas: un procedimiento difícil y que toma mucho tiempo. En este trabajo se presenta una descripción de la técnica que permite la disociación enzimática de músculos largos de ratón como el soleus o el extensor digitorum longus (EDL), lo cual aumenta el espectro de tipos de fibras y el número de ellas disponibles para el estudio de los fenómenos biológicos en el músculo esquelético. Además se compara la cinética de los transitorios de Ca2+ en fibras de soleus y EDL y se prueba la utilidad del modelo en otros experimentos que utilizan técnicas de fisiología, bioquímica y biología celular. Esto abre la posibilidad de utilizar todo el espectro de fibras musculares para estudiar la biología muscular y la fisiopatología de las enfermedades musculares.

The laboratory and clinical diagnosis strategy in MYH9 disorders / 中华检验医学杂志

Myosin heavy chain 9 (MYH9)disorders are a group of ihherited thrombocytopenias resulted from the mutation of MYH9 gene,including May-Hegglin anomaly,Epstein syndrome,Fechtner syndrome and Sebastian syndrome.MYH9 disorders are very often misdiagnosed as idiopathic thrombocytopenic purpura (ITP).For better understanding of MYH9 of clinical and laboratory and getting enough attention in clinical practice,this review will focus on the pathogenesis,clinical manifestations,laboratory examination and differential diagnosis.

Analysis of the expression in platelets membrane glycoprotein of the MYH9-RD family by flowcytometry / 中华检验医学杂志

Objective To explore the pathogenic mechanism by detecting the expression of membrane glycoprotein in the platelets of nonmuscle myosin heavy chain 9 related disease (MYH9-RD)patients.Methods Periperal bloods were obtained from 11 MYH9-RD patients and 7 normal family members.Flow cytometry was used for detecting the expression of the platelet membrane glycoprotein including GP Ⅱ b/Ⅲa(CD41/61),GP Ⅰ a(CD49b),GP Ⅰ b/Ⅸ/Ⅴ (CD42a) GP Ⅰ b(CD42b) and GPⅣCD36).Results The expression fluorescence intensity of platelet membrane glycoprotein GP Ⅱ b/Ⅲ a CD41/61),GPⅠa(CD49b),GP Ⅰ b/Ⅸ/Ⅴ (CD42a) GP Ⅰ b(CD42b) and GPⅣ (CD36) are 653.7 ±192.7,420.0 ± 151.3,667.7 ± 371.3 and 236.4 ± 64.2 respectively,which are significantly higher than those in normal controls (406.7 ± 126.1,181.2 ± 29.3,271.4 ± 91.6 and 136.1 ± 23.5 ; P ＜ 0.01) ; The expression of GP Ⅰ a(CD49b) was lower in patients with MYH9-RD (139.1 ± 54.9) than that in normal controls (192.2 ± 143.4),but there was no significant difference (P ＞ 0.05).Conclusion In our study,the diverse clinical manifestations in patients with MYH9-RD is probably associated with the expression level of platelet membrane glycoprotein

Response of masticatory muscles to passive stretch stimulus - from perspectives of functional appliances / 대한치과교정학회지

OBJECTIVE: The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. METHODS: Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed after 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). RESULTS: The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins after 7 days. CONCLUSIONS: The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.

Changes in the Expression of Smooth Muscle Myosin Heavy Chain mRNA following Partial Bladder Obstruction or Spinal Cord Injury in Rat: A Preliminary Study / 대한비뇨기과학회지

PURPOSE: The smooth muscle myosin heavy chain (SMMHC) isoform composition has been actively researched in a partial bladder obstruction (PBO) or spinal cord injury (SCI) model. Even though rat is an ideal animal for studying bladder physiology, there were very few reports about the changes of the SMMHC isoforms in the PBO or SCI injured bladder of rat. We developed two polymerrase chain reaction (PCR) primer sets to amplify the isoforms and we applied the primers to the PBO and SCI rat models. MATERIALS AND METHODS: Female rats had their bladder necks surgically obstructed or they were subjected to spinal cord injury. Six weeks after the event, the bladders were excised. The expression of the C-terminal (SM1 and SM2) and N-terminal (SM-A and SM-B) isoforms of SMMHC was analyzed by performing reverse transcriptase-PCR (RT-PCR). RESULTS: The control bladder showed only the SM-B isoform in the C-terminal. However, the bladder after SCI showed an increased SM-A to SM-B ratio. In case of PBO, the ratios were variable. A decreased SM1 expression was noted in the PBO and SCI groups when compared to the control group (p<0.05). CONCLUSIONS: Our female rat models for PBO or SCI demonstrates changes in the expression of smooth muscle myosin heavy chain isoforms. We will apply this primer set for studying of rat muscular physiology in PBO or SCI model.

Effect of trigeminus nerves innervation on the phenotype of MHC after facial paralysis / 北京大学学报(医学版)

Objective:To discuss the effect of trigeminus nerves on the phenotype of MHC after facial paralysis; Methods:The morphologic changes were observed by histochemical methods 、the phenotype of MHC by SDS PAGE 、the tension of contraction and the threshold value of electrical stimulation by electrical physiological methods; Results: trigeminus nerves could delay the decomposing of MHC, maintain the tension of contraction and the threshold value of electrical stimulation; Conclusion: Sensory nerves could delay the muscular atrophy ,and should be repaired when we repair motor nerves.

Distribution of Myosin Heavy Chain Isoforms in the Musculus Uvulae of Patients with Snoring and Obstructive Sleep Apnea Syndrome Using ATPase Staining Method / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: OSAS is thought to be due to an excessive loss of muscle tone in the upper airway or an abnormal reflex regulation of upper airway function during sleep. The aim of this study was to investigate the distribution of myosin heavy chain (MHC) isoforms of musculus uvulae in OSAS and snorers. Materials and Methods: Thirty seven patients included in the study underwent an uvulo-palato-pharyngoplasty (UPPP). All subjects had polysomnographic study before UPPP. ATPase stain at pH 9.4 were applied to muscle specimens obtained during UPPP. The numbers of MHC type I and II isoforms were counted. The patients were divided into three groups according to their repiratory disturbance index (RDI):mild (0-20), moderate (21-40), severe (>40). The differences in the distribution of muscle fiber types were compared between these groups. The correlation between the distribution of the fibers and the body mass index / age / RDI / minimum O2 saturation / duration of sleep apnea was investigated. RESULTS: The mean percentages standard deviation of type I fibers according to the severity of sleep apnea were as follows:22.5+/-3.2% in mild sleep apnea group (n=5), 19.8+/-2.3% in moderate sleep apnea group (n=1), 17.5+/-3.6% in severe sleep apnea group (n=1). There were statistically significant differences in the distribution of MHC type I and II isoforms between mild group and moderate and / or severe group (p.05). CONCLUSION: The proportion of MHC type I isoforms in musculus uvulae was decreased according to the severity and duration of sleep apnea (p<.01).

Effects of thyroid hormone on the myosin heavy chain mRNA expression in cardiac myocytes induced by angiotensin Ⅱ / 中国病理生理杂志

AIM: To study the effect of thyroid hormone on the expressional change of myosin heavy chain(MHC) gene in cardiomyocyte induced by angiotensinⅡ(AngⅡ) and its potential mechanism. METHODS: Cardiac myocyte was cultured according to the method of Simpson. 10 -8 mol/L T_3 and 10 -7 mol/L AngⅡ were added to the culture medium,respectively or synchronously. After 48 h,the expression of ? and ?-MHC mRNA in myocytes were detected by RT-PCR. The protein kinase C activation were detected by PepTag non-radioactive PKC assay. The incorporation of -Leucine and -thymine to test the protein and DNA synthesis in myocytes were also performed. RESULTS: AngⅡalone increased the incorporation of -Leucine of myocytes while it had no effect on the incorporation of -thy mine. The expression of ?-MHC mRNA was increased and the expression of ?-MHC mRNA was decreased significantly at the condition of AngⅡ. The enhanced PKC activation was induced by AngⅡalso. When AngⅡand T_3 were added to the culture medium synchronously,though the incorporation of -leucine and -thymine were not changed compared with AngⅡ treated alone. The ?-MHC mRNA expression was increased and the ?-MHC mRNA expression was decreased significantly. The PKC activation of the myocytes also was decreased. CONCLUSIONS: T_3 inhibited the expressional change of myosin heavy chain gene in cardiac myocytes induced by AngⅡ. The effect of T_3 on the change of PKC activation in cardiac myocytes may be one of its mechanisms.

Calcineurin is involved in signal transduction of myocaridal remodeling in patients with congestive heart failure / 中国病理生理杂志

AIM: To investigate the involvement of calcineruin (CaN) signal pathway mediated by angiotension Ⅱ (Ang Ⅱ) in the myocardial remodeling mechanism in patients with congestive heart failure (CHF). METHODS: 39 patients of mitral valve disease with CHF were randomly selected and 30 cases of healthy persons were included as controls. Cardiac function parameters were measured by echocardiography. Concentration of Ang Ⅱ in plasma and myocardial tissues were determined by radioimmunoassay. Immunoprecitipation was used to assay the protein expression and phosphorylation CaN, nuclear factor of activated T cells (NFAT_3),zinc finger transcription factor (GATA_4) in myocardial tissues. The mRNA expression of ?-myosin heavy chain (?-MHC) was measured by RT-PCR. RESULTS: The Ang Ⅱ concentrations in patients with CHF were positively correlated with the parameters of the cardiac dialtion respectively, but negatively correlated with the paremeters of cardiac function. Compared to the control group, protein of CaN and GATA_4, phosphorylation of CaN, and ?-MHC mRNA expression in myocardial tissues in CHF groups were highly expressed and their expression were positively correlated to the levels of CHF, but the phosphorylation of NFAT_3 was negatively correlated with the levels of CHF. CONCLUSION: CaN signal pathway may play important roles in the myocardial remodeling in CHF.