Association of SLC26A4 muations with clinical features and thyroid function in deaf infants with enlarged vestibular aqueduct

Pendred syndrome and non-syndromic recessive deafness associated with enlarged vestibular aqueduct (NSRD with EVA) are caused by mutations in the SLC26A4 (PDS) gene. Unlike NSRD with EVA, Pendred syndrome is characterized by goiter, which may be present after early adulthood. However, the clinical diagnosis of these two disorders is difficult in deaf children. Expression of the SLC26A4 gene may be responsible for iodide transport in the thyroid as well as for formation and function of the inner ear. Here, we analyzed the SLC26A4 gene and performed thyroid function tests (FT3, FT4, TSH, and Thyroglobulin) on six congenitally deaf infants (mean age 2.7 years) with EVA. Mutation of the SLC26A4 gene was identified in five patients: four were compound heterozygous (H723R/919−2A>G, H723R/IVS15+5G>A, H723R/R581S, IVS7-2A>G/IVS8+1G>A), the fifth had a frameshift mutation (322delC). All the patients demonstrated an elevation of serum thyroglobulin level. FT3 level was elevated in four of the five patients. The patient who did not have a detectable gene mutation showed normal thyroid function. We conclude that the mutations in the SLC26A4 gene identified here are highly associated with high serum thyroglobulin levels in congenital and deafness infants. These mutations may be of value for the diagnosis of Pendred syndrome and NSRD with EVA.     

Intermittent short-duration exposure to low wall shear stress induces intimal thickening in arteries exposed to chronic high shear stress

We sought to determine whether intermittent short-duration exposure to low wall shear stress could induce intimal thickening in arteries chronically exposed to high shear stress. An arteriovenous fistula (AVF) was created between the left common carotid artery and the corresponding external jugular vein in 20 Japanese white male rabbits. After 4 weeks, blood flow was increased 10-fold to 182 +/- 39 ml/min and shear stress was increased to 33.4 +/- 13 dyn/cm(2). The AVF was then occluded for 1 h by finger compression with an 85% reduction in carotid artery blood flow (27 +/- 7 ml/min) and a reduction in wall shear stress to 4.9 +/- 1.7 dyn/cm(2) (P < 0.0001). Release of finger compression restored flow to the AVF and high shear stress to the carotid artery. This procedure was repeated at weekly intervals with a cumulative total of 4 h of low shear stress exposure. Arteries exposed to intermittent low shear stress developed a layer of intimal thickening which consisted of 3-4 layers of smooth muscle cells lined with thin elastic fibers and medial hyperplasia. Control arteries exposed to 8 weeks of continuous high shear had no intimal thickening. Transient exposure to low shear stress upregulated TGF-beta1, MMP-2, -14, and TIMP-2 gene expression while MMP-9 expression was downregulated. We conclude that repeated, intermittent short-duration exposure to low shear stress in the setting of high flow and high shear stress can induce arterial intimal thickening. Short-duration alterations in hemodynamic forces can induce rapid vascular cell message expression, which may effect arterial remodeling. This experiment suggests that a threshold value of 5 dyn/cm(2) may be needed in order to initiate and sustain the intimal thickening response.     

Autopsy case of desminopathy involving skeletal and cardiac muscle

Desminopathy is a familial or sporadic skeletal and cardiac muscular dystrophy caused by mutation in the desmin gene. Desmin-reactive deposits in the affected muscles are the morphological hallmarks of this disease. Herein is reported an autopsy case of a 57-year-old Japanese man with adult-onset skeletal muscle weakness and atrioventricular (A-V) conducting block, with a missense A337P mutation in exon 5 of the desmin gene. Disease onset occurred when the patient was 45 years old. The initial presentation was lower limb weakness, and the weakness progressed to the upper limbs. When the patient was 51 years old, a cardiac pacemaker was implanted due to complete A-V block. When the patient was 53 years old, respiratory insufficiency occurred due to weakness of respiratory muscles, and the patient died at the age of 57 years. On autopsy, intrasarcoplasmic desmin-immunoreactive deposits were identified in the skeletal and cardiac muscle, and abnormal accumulations of granulofilamentous material were identified at the ultrastructural level. In the cardiac conducting system, calcification was observed at the bundle of His, and sporadic calcium deposits were observed at the left and right bundle branches.     

IL-4Ralpha polymorphism in regulation of IL-4 synthesis by T cells: implication in susceptibility to a subset of murine lupus

To thoroughly understand the role of IL-4 in the pathogenesis of systemic lupus erythematosus (SLE), a prototypic antibody-mediated systemic autoimmune disease, we examined the potential of in vitro IL-4 production by anti-CD3 mAb-stimulated splenic T cells in SLE model of NZB, BXSB and related mouse strains. Unexpectedly, both SLE-prone NZB and BXSB mice had a limited potential to produce IL-4, while disease-free NZW mice had a high potential. Levels in (NZB x NZW) F1 and (NZW x BXSB) F1 were in between. Genome-wide search for quantitative trait loci (QTL) controlling this variation identified a single significant QTL in the vicinity of IL-4Ralpha gene on chromosome 7. Sequence analysis of IL-4Ralpha cDNA revealed that there are 17 nucleotide substitutions resulting in eight amino acid changes between NZB and NZW strains. BXSB showed the identical sequence, as did NZB. Thus, it was suggested that the NZW-type polymorphism controls a high potential and the NZB/BXSB-type polymorphism controls a low potential for IL-4 production by T cells. Linkage studies using NZW x (NZW x BXSB) F1 male and (NZB x NZW) F1 x NZW female back-cross mice revealed that the BXSB/NZB-type IL-4Ralpha polymorphism significantly linked to BXSB, but not to (NZB x NZW) F1 lupus. Thus, the low IL-4-producing phenotype appears to predispose to SLE in BXSB, but not NZB-related strains, suggesting that the role of IL-4 in the pathogenesis may differ between certain subsets of SLE, even if they show similar disease phenotypes.     

Scrape and fine-needle aspiration cytology of extraskeletal osteosarcoma

Extraskeletal osteosarcoma is a rare malignant soft tissue tumor whose cytologic findings are infrequently reported. We describe scrape and fine-needle aspiration biopsy (FNAB) cytology findings of an extraskeletal osteosarcoma in the right shoulder of a 24-yr-old man. Initial computed tomography revealed multiple ossification foci within the lesion. After excision of the primary tumor, the tumor recurred 13 months later. Scrape smears of both the primary tumor and FNAB smears of the recurrent tumor revealed moderate cellularity, cell clusters, and individual cells, closely associated with dense, homogeneous, acellular matrix material. The cells had elongated, oval, or partially bizarre-shaped nuclei with a coarse chromatin pattern and prominent nucleoli. The scrape smears contained large fragments of matrix material consistent with osteoid.     

Side-to-side linking of myocardial cells in hypertrophic cardiomyopathy: whole heart microscopic observation with tangential sections

By cross-section or longitudinal section, it is difficult to investigate longitudinal features of myocardial cells in the whole heart. Here, introducing the use of tangential sections to obtain longitudinal aspect of myocardial cells in any part of myocardium, the authors evaluated myocardium in the left ventricle in 10 normal hearts and four hearts with hypertrophic cardiomyopathy (HCM). Tangential sections were obtained by peeling the superficial layer of myocardium. After peeling the whole surface, secondary deep layer was peeled. These procedures were repeated more than five times through the wall. Intercalated discs (ICD) were observed immunohistochemically with anti-N-cadherin and antidesmoplakin. In normal hearts, myocardial cells were cut longitudinally and ran parallel in tangential sections. They linked end-to-end with simple and regular ICD with average lengths of 120-130 microm and average sarcomere numbers of 56-65. In HCM hearts, many myocardial cells were cut almost longitudinally running approximately parallel in tangential sections. Myocardial cells frequently showed side-to-side linking characterized by skewed ICD, indistinct ICD counterparts, and longitudinally arranged ICD. Two young HCM hearts had circle-shaped ICD and vacuole-like structures highlighted by immunostaining for N-cadherin, which were actually extracellular structures comparable with irregular side-to-side linking. It is considered that side-to-side linking of myocardial cells is a characteristic microscopic feature in HCM rather than myocardial disarray.     

Neurite extension of DRG neurons by gicerin expression is enhanced by nerve growth factor

Gicerin, a cell adhesion molecule, is expressed in dorsal root ganglion (DRG) and sciatic nerves during chick development. This molecule re-appears in these tissues after an injury to the sciatic nerve. In the present study, we investigated the expression of nerve growth factor (NGF) in the regenerating sciatic nerve of chicks and the effects of NGF on the expression and neurite activities of gicerin in DRG. In the sciatic nerve after a crush injury, the expression of NGF and gicerin increased in the Schwann cells and in the nerve fibers, respectively. NGF promoted the neurite projections from in vitro DRG on the gicerin ligands, which were inhibited by anti-NGF antibody. The gicerin mRNA expression increased in the DRG with NGF, which was inhibited by the co-incubation with anti-NGF antibody. These results indicate that NGF might therefore enhance the expression of gicerin in DRG, thereby promoting the gicerin-dependent neurite extension during sciatic nerve regeneration.     

Myopathy phenotype in transgenic mice expressing mutated PABPN1 as a model of oculopharyngeal muscular dystrophy

Autosomal dominant oculopharyngeal muscular dystrophy (OPMD)is a late-onset disorder characterized clinically by progressiveptosis, dysphagia and limb weakness, and by unique intranuclearinclusions in the skeletal muscle fibers. The disease is causedby the expansion of a 10-alanine stretch to 12–17 alanineresidues in the poly(A)-binding protein, nuclear 1 (PABPN1;PABP2). While PABPN1 is a major component of the inclusionsin OPMD, the exact cause of the disease is unknown. To elucidatethe molecular mechanism and to construct a useful model fortherapeutic trials, we have generated transgenic mice expressingthe hPABPN1. Transgenic mice lines expressing a normal hPABPN1with 10-alanine stretch did not reveal myopathic changes, whereaslines expressing high levels of expanded hPABPN1 with a 13-alaninestretch showed an apparent myopathy phenotype, especially inold age. Pathological studies in the latter mice disclosed intranuclearinclusions consisting of aggregated mutant hPABPN1 product.Furthermore, some TUNEL positive nuclei were shown around degeneratingfibers and a cluster of it in the lesion in necrotic musclefibers. Interestingly, the degree of myopathic changes was moreprominent in the eyelid and pharyngeal muscles. Further, muscleweakness in the limbs was apparent as shown by the fatigabilitytest. Nuclear inclusions seemed to develop gradually with aging,at least after 1 week of age, in model mouse muscles. We establishedthe first transgenic mouse model of OPMD by expressing mutatedPABPN1, and our model mice appear to have more dramatic alternationsin myofiber viability. ^* To whom correspondence should be addressed. Tel: +81 963736083; Fax: +81 963736599; Email: yamamura{at}gpo.kumamoto-u.ac.jp