Shin Fujimoto

Proteasome expression in the skeletal muscles of patients with muscular dystrophy.

Abstract Previous investigators have suggested that proteolysis by calpain, a Ca2+-dependent protease, causes muscle fiber degradation in Duchenne and Becker muscular dystrophies (DMD/BMD). Recent evidence indicates that the nonlysosomal ATP-ubiquitin-dependent proteolytic complex (proteasomes) participates in muscle wasting during various catabolic states and in muscle fiber degradation in physiological or pathological conditions. To elucidate the possible role of proteasomes in dystrophic muscles, routine histochemistry and immunohistochemistry of 26S proteasomes were performed on muscle biopsy specimens obtained from patients with various neuromuscular disorders including DMD/BMD, polymyositis (PM), amyotrophic lateral sclerosis, and peripheral neuropathies, and on normal human muscle specimens. Immunohistochemically, proteasomes were located in the cytoplasm in normal human muscle, but their staining intensity was faint. Compared to control muscles, abnormal increases in both proteasomes and ubiquitin were demonstrated mainly in the cytoplasm of necrotic fibers and to a lesser extent in regenerative fibers in DMD/BMD and PM. Non-necrotic, atrophic fibers in all diseased muscles showed moderate or weak immunoreactions for the proteins; their staining intensities were stronger than those of control muscle fibers. Both proteins often colocalized well. Not all dystrophin-deficient muscle fibers showed a strong reaction for proteasomes. Our results showed increased proteasomes in necrotic and regenerative muscle fibers in DMD/ PMD, although this may not be disease-specific up-regulation. We suggest that the ATP-ubiquitin-dependent proteolytic pathway as well as the nonlysosomal calpain pathway may participate in muscle fiber degradation in muscular dystrophy.

Expression of three calpain isoform genes in human skeletal muscles

Calpain is thought to be involved in muscular degradation in progressive muscular dystrophy (PMD), especially Duchenne and Becker muscular dystrophies. To assess the expression of calpain genes in skeletal muscles of patients with myopathies, we examined mRNA levels of three calpain isoforms by the quantitative reverse transcriptase-polymerase chain reaction method in biopsied muscles from control, PMD and amyotrophic lateral sclerosis (ALS) patients. There was a statistically significant increase in calpain 1 and calpain 2 mRNA levels in PMD and ALS patients as compared to controls. In contrast, there was a decrease in expression of calpain 3 mRNA in PMD, but it was not statistically significant. Expression of calpain 1 and calpain 2 positively correlated with each other, but not with calpain 3. These results indicate that expression of calpain 1 and calpain 2, but not calpain 3, are upregulated in diseased human muscles, likely playing a regulatory role in the process of myofibrillar degradation at the transcriptional as well as posttranslational level.

A new dysferlin gene mutation in two Japanese families with limb-girdle muscular dystrophy 2B and Miyoshi myopathy

We found a new dysferlin gene mutation in two Japanese families, one with limb-girdle muscular dystrophy 2B and the other with Miyoshi myopathy. All patients in the limb-girdle muscular dystrophy 2B family showed apparent proximal dominant muscle atrophy and weakness, whereas a patient with Miyoshi myopathy in the second family showed distal muscle involvement at an early stage. The common clinical feature of all patients in both families was preferential involvement of calf muscles rather than the tibialis anterior muscle, which was confirmed by muscle computed tomography scan. All patients in both families shared the same homozygous alleles for chromosome 2p13 markers, and dysferlin gene analysis revealed a novel missense mutation, a G to A transition at nt 5882, which changed aspartic acid to asparagine at codon 1837. Allele-specific polymerase chain reaction analysis was used for confirmation of the mutation and for genotype analysis of the family members.

A clinicopathological study of a patient with anti-Hu-associated paraneoplastic sensory neuronopathy with multiple cranial nerve palsies

Only a few cases of paraneoplastic neurologic syndrome with multiple cranial palsies have been reported. This is the case report of a patient with small-cell lung cancer and a high titer of anti-Hu antibodies who developed a tonic left pupil and multiple cranial nerve palsies, including palsies of the left fifth through tenth nerves and both twelfth nerves, as in Garcin syndrome showing at least more than seven ipsilateral cranial nerve palsies, in the course of paraneoplastic sensory neuronopathy (PSN). Pathologic examination revealed no metastasis or direct invasion of malignancy with gliosis and perivascular inflammation throughout the brainstem, indicating paraneoplastic encephalomyelitis (PEM). The numbers of EBM11+ cells (probably reactive microglia), CD8+ cells, and CD4+ cells increased. Intracellular adhesion molecule-1 and lymphocyte function associated molecule-1 were expressed intensely on the endothelia of microvessels and were found to have infiltrated mononuclear cells around microvessels in the brainstem. Multiple cranial nerve palsies and their effects including the tonic pupil are likely due to the paraneoplastic effect of the primary systemic malignancy.

Chronic sensory neuronopathy associated with human T-cell lymphotropic virus type I infection

We described two patients with chronic sensory neuronopathy who had anti-HTLV-I antibody in serum and cerebrospinal fluid but no signs of myelopathy. A sural nerve specimen revealed severe degeneration of myelinated and unmyelinated axons. The second patient had subclinical Sjögrens syndrome suggestive of a possible link among human T-cell lymphotropic virus type I (HTLV-I), Sjögrens syndrome and sensory neuronopathy, respectively. The broad spectrum of neurologic disorders associated with HTLV-I infection now would include chronic sensory neuronopathy.

Adhesion molecule expression in experimental myositis

Experimental allergic myositis (EAM) in Lewis rats, induced with partially purified myosin, is regarded as a model of human polymyositis. To clarify the role of adhesion molecules in the pathogenesis of EAM in Lewis rats, we investigated intramysial expressions of the intercellular adhesion molecule (ICAM)‐1 and vascular cell adhesion molecule (VCAM)‐1, and the serum level of soluble ICAM‐1 in EAM rats. All the EAM rat muscles had scattered inflammatory foci, as well as cell infiltration and necrosis, by week 4 after the initial immunization (i.e., day 0 after the last immunization). As compared with the control muscles, ICAM‐1 and VCAM‐1 were strongly expressed immunohistochemically in the endothelium of vessels in the endomysium and perimysium, and to lesser extents in the inflammatory infiltrates and on the sarcolemma of nonnecrotic muscle fibers adjacent to the inflammatory infiltrates or invaded muscle fibers. ICAM‐1 in the muscle extracts and sera from EAM rats increased on each test day, as compared with extracts from the normal controls. The values peaked on day 0 after the last immunization, then gradually decreased with time. ICAM‐1 elevations in the muscle extracts were correlated with the percent of sections that had inflammatory lesions (P = 0.032) and the histological scores (P = 0.005) on day 0, whereas there was no significance on days 3 and 7. These findings suggest that the adhesion molecules ICAM‐1 and VCAM‐1 increase in the early stage of EAM, and function in the initiation of the inflammatory process of myositis.

Solitary metastasis of prostatic cancer to the internal auditory canal

We report a 56-year-old man with a metastatic prostatic tumor who developed left orbital meatus syndrome as the first manifestation. Magnetic resonance imaging (MRI) showed a swollen lesion in the left internal auditory canal that was isointense on T1-weighted images, hyperintense on T2-weighted images, and marked by enhanced after the administration of gadolinium. A biopsy of the affected lesion confirmed the prostatic origin of the metastasis.

Diagnostic impact of baseline cerebral blood flow in patients with acute ischemic stroke prior to intravenous recombinant tissue plasminogen activator therapy

OBJECTIVE To determine whether severe cerebral perfusion defects measured by SPECT prior to rt-PA therapy attribute to severe intracerebral hemorrhage (SICH). METHODS We measured baseline cerebral blood flow (CBF) using technetium-99m-labeled hexamethylpropyleneamine oxime (99mTc-HMPAO) SPECT qualitatively prior to rt-PA therapy, in 52 consecutive patients (range 38-93 years). The degree and extent of the asymmetry of local CBF were analyzed semi-quantitatively. We did not administrate rt-PA in patients with severe perfusion defects. Clinical outcome and the incidence of SICH were studied. RESULTS Three (5.8%) patients had severe perfusion defects that were undetected by CT and/or DWI. The other 49 (94.2%) patients had mild perfusion defects. The asymmetry of local CBF was 0.08±0.08 (n=3) and 0.3±0.15 (n=49) in the two groups, respectively. The percentages of the ipsilateral hemisphere in which perfusion was impaired severely were 17.5±9.5% (n=3) and 0.43±0.87% (n=49). Two patients were found petechial hemorrhage, but there was no patient who developed SICH in the former group following conventional antithrombotic therapy. In the latter group, SICH occurred in 1/49 (2.0%) patient following rt-PA therapy. CONCLUSION These results suggest that rt-PA therapy for patients with severe cerebral perfusion defects may cause SICH and baseline CBF may contribute to identify patients at high risk for SICH after intravenous rt-PA therapy.

Photodynamic Therapy of Malignant Gliomas

Recently, the clinical applications of photodynamic therapy (PDT) in the management of malignant brain tumors have attracted significant attention. Meta-analysis of the observational studies on this treatment in high-grade gliomas (Eljamel, 2010) included more than 1,000 patients and reported median survival in cases of newly diagnosed and recurrent glioblastoma multiforme (GBM) of 16.1 and 10.3 months, respectively. In some series, increase in the long-term survival rates was also observed. Few controlled trials demonstrated statistically significant impact of PDT on prolongation of survival in patients with GBM in comparison to conventional management. The main treatment-related adverse event is short-lasting excessive photosensitivity of the skin and retina after photosensitizer administration, but its negative consequences can be easily avoided with appropriate protective measures. Overall, PDT may be considered to be a safe and effective adjuvant therapeutic option for patients with newly diagnosed and recurrent malignant gliomas. Aggressive tumor resection seems to be an important prerequisite to maximize treatment efficacy.

Immediate recurrence of a carotid plaque following carotid endarterectomy

Abstract Thrombus occurring at the cervical carotid bifurcation is usually caused by vascular intimal atheromatous change, such as ulceration or dissection. Such thrombosis based on an abnormal vascular lesion can disappear after normalization of the intima by carotid endarterectomy (CEA). While we have evaluated the postoperative state of the carotid artery with a USG after CEA, two patients presented with recurrent cervical thrombus in the immediate postoperative period without hypercoagulative abnormalities. The first case is a 56-year-old male who presented with cerebral embolic infarction. Carotid plaque that had transiently disappeared via CEA, however, repeatedly appeared at the same area on the postoperative fourth week. The hypo-echoic lesion on the ultrasonography (USG) was strongly suspected to be thrombus formation. The second case was a 67-year-old male with multiple cerebral embolic infarctions. USG demonstrated pulsatively movable cervical carotid plaque with hypo-echogenicity, which was removed by CEA and identified as hematoma in the atherosclerotic intima. However, thrombus was reformed at the same lesion, as seen on the USG on the postoperative third week. Both were gradually dissolved by anticoagulant therapy. The postoperative USG was very effective to check intimal abnormalities, and the postoperative thrombus formation might not be so rare.