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Biomedical subjects

Fujio Umehara

Publications and source records attributed to Fujio Umehara.

At least 19 recordsLinked to original sources
PubMed2006

Elevated anxiety-like and depressive behavior in Desert hedgehog knockout male mice.

To investigate the functional role of Desert hedgehog (Dhh) gene in the nervous system, we examined motor, sensory, learning and memory functions as well as mood in Dhh knockout (KO) mice. Dhh KO male mice exhibited prolonged immobility time compared with wild-type male mice in the forced swimming test, and showed enhanced inhibition in the Vogel's conflict model. These findings suggest that Dhh KO male mice exhibited enhanced anxiety and depressive behavior compared with wild-type male mice. In contrast, Dhh KO female mice did not show any significant difference compared to wild-type female mice. These behavioral abnormalities of Dhh KO male mice may be due to lower testosterone levels with abnormal development of the testes caused by Dhh-null mutation.

Acoustic Stimulation↗
PubMed2006

MRI studies of spinal visceral larva migrans syndrome.

We report serial MR findings in four patients with myelitis caused by visceral larva migrans syndrome due to Toxocara canis or Ascaris suum infection. MR imaging revealed spinal cord swelling with or without gadolinium enhancement in three patients. T2-weighted images showed high signal intensities preferentially located in both lateral and posterior columns. Antihelmintic and corticosteroid treatment yielded improvement in neurologic deficits and spinal lesions. However, one patient with T. canis infection relapsed associated with reappearance of MRI abnormalities.

Adrenal Cortex Hormones↗
PubMed2006

The structural and functional integrity of peripheral nerves depends on the glial-derived signal desert hedgehog.

We show that desert hedgehog (dhh), a signaling molecule expressed by Schwann cells, is essential for the structural and functional integrity of the peripheral nerve. Dhh-null nerves display multiple abnormalities that affect myelinating and nonmyelinating Schwann cells, axons, and vasculature and immune cells. Myelinated fibers of these mice have a significantly increased (more than two times) number of Schmidt-Lanterman incisures (SLIs), and connexin 29, a molecular component of SLIs, is strongly upregulated. Crossing Dhh-null mice with myelin basic protein (MBP)-deficient shiverer mice, which also have increased SLI numbers, results in further increased SLIs, suggesting that Dhh and MBP control SLIs by different mechanisms. Unmyelinated fibers are also affected, containing many fewer axons per Schwann cell in transverse profiles, whereas the total number of unmyelinated axons is reduced by approximately one-third. In Dhh-null mice, the blood-nerve barrier is permeable and neutrophils and macrophage numbers are elevated, even in uninjured nerves. Dhh-null nerves also lack the largest-diameter myelinated fibers, have elevated numbers of degenerating myelinated axons, and contain regenerating fibers. Transected dhh nerves degenerate faster than wild-type controls. This demonstrates that a single identified glial signal, Dhh, plays a critical role in controlling the integrity of peripheral nervous tissue, in line with its critical role in nerve sheath development (Parmantier et al., 1999). The complexity of the defects raises a number of important questions about the Dhh-dependent cell-cell signaling network in peripheral nerves.

Aging↗
PubMed2006

Desert hedgehog-patched 2 expression in peripheral nerves during Wallerian degeneration and regeneration.

Hedgehog proteins are important in the development of the nervous system. As Desert hedgehog (Dhh) is involved in the development of peripheral nerves and is expressed in adult nerves, it may play a role in the maintenance of adult nerves and degeneration and regeneration after injury. We firstly investigated the Dhh-receptors, which are expressed in mouse adult nerves. The Dhh receptor patched(ptc)2 was detected in adult sciatic nerves using RT-PCR, however, ptc1 was undetectable under the same experimental condition. Using RT-PCR in purified cultures of mouse Schwann cells and fibroblasts, we found ptc2 mRNA in Schwann cells, and at much lower levels, in fibroblasts. By immunohistochemistry, Ptc2 protein was seen on unmyelinated nerve fibers. Then we induced crush injury to the sciatic nerves of wild-type (WT) and dhh-null mice and the distal stumps of injured nerves were analyzed morphologically at different time points and expression of dhh and related receptors was also measured by RT-PCR in WT mice. In dhh-null mice, degeneration of myelinated fibers was more severe than in WT mice. Furthermore, in regenerated nerves of dhh-null mice, minifascicular formation was even more extensive than in dhh-null intact nerves. Both dhh and ptc2 mRNA levels were down-regulated during the degenerative phase postinjury in WT mice, while levels rose again during the phase of nerve regeneration. These results suggest that the Dhh-Ptc2 signaling pathway may be involved in the maintenance of adult nerves and may be one of the factors that directly or indirectly determines the response of peripheral nerves to injury.

Animals↗
PubMed2005

Chronic progressive sensory ataxic neuropathy associated with limited systemic sclerosis.

We report the case of a 33-year-old woman with limited systemic sclerosis and chronic progressive sensory ataxic neuropathy. Sural nerve biopsy showed loss of myelinated fibers mostly those of large diameter, axonal degeneration and infiltration of macrophages, but no signs of vasculitis. Physical examination, laboratory testing, neurophysiological and neuroradiological examinations suggested that the dorsal root was primarily affected in this patient. Cytokine analysis by multiplex bead array assay revealed that IL-1beta and GM-CSF were increased both in serum and CSF. Although her symptoms did not respond to corticosteroid therapy, intravenous immunoglobulin (IVIg) therapy resulted in marked improvement. IVIg could be effective in case of immune-mediated reversible neuronal dysfunction associated with collagen disease without vasculitis.

Adult↗
PubMed2005

[Chronic progressive cervical myelopathy with HTLV-I infection: variant form of HAM/TSP].

We report four patients with slowly progressive cervical myelopathy. The four patients had several features in common; 1) progressive cervical myelopathy with a duration of several months to years, 2) abnormal lesions in the cervical to upper thoracic cord levels with or without gadolinium enhancement, 3) anti-HTLV-I antibodies were positive both in serum and CSF, 4) high levels of HTLV-I proviral load in PBMC. The calculated risk of HAM/TSP in two patients showed a high value, comparable to those of HAM/TSP, and higher than those of healthy HTLV-I carrier. Because the clinical and laboratory findings of these four cases show similarities to those of HAM/TSP, we propose that these four cases may be a variant form of HAM/TSP.

Aged↗
PubMed2004

Beneficial effects of mild lifelong dietary restriction on skeletal muscle: prevention of age-related mitochondrial damage, morphological changes, and vulnerability to a chemical toxin.

The effect of mild lifelong dietary restriction (DR) on age-related changes was investigated in rats. Histopathological findings were compared between 25-month-old male rats fed ad libitum and 25-month-old male rats that were calorie restricted (80% of ad libitum calories; protein 15%) from 9 weeks of age. DR-fed rats retained motor activity even in old age compared with ad libitum-fed rats. Histopathological studies on soleus muscles clarified myopathic changes in the ad libitum-fed rats, including variations in fiber size and an increase in the number of central nuclei. Increased non-grouping atrophic angulated fibers were also observed. The specimens revealed a confused arrangement of the mitochondria and decreased mitochondrial electron transduction enzyme activities, indicating mitochondrial insults in the ad libitum-fed rats. In contrast, no myopathic changes, little mitochondrial insult, and fewer angulated fibers were recognized in the DR-fed rats. The accumulations of heme oxygenase-1, alphabeta crystallin, 8-hydroxydeoxyguanosine, and heat shock protein 27 were recognized in ad libitum-fed rats, indicating the attack of oxidative stress. In contrast, the expressions of these proteins were suppressed in DR-fed rats. The results suggest that even mild calorie restriction is enough to attenuate oxidative stress and age-related morphological changes in skeletal muscle. Additionally, DR was effective in protecting against methylmercury-induced pathological changes. Small fiber size and suppression of mitochondrial electron transduction enzyme activities in skeletal muscle and degenerative changes in peripheral nerves were milder in methylmercury-exposed DR-fed rats. The results indicate that mild lifelong DR also protects skeletal muscle and peripheral nerves against a chemically-induced form of oxidative stress.

Aging↗
PubMed2004

[Thiamine deficiency polyneuropathy after gastrectomy associated with high level of serum vascular endothelial growth factor (VEGF). A case report].

We report a 66-year-old man who developed vitamin B1 deficiency polyneuropathy long after a gastrectomy. After a preceding bronchial infection, the patient noticed numbness and weakness in his extremities, followed by generalized edema and exertional dyspnea. He had undergone subtotal gastrectomy due to duodenal ulcer at age 19. His daily oral intake of food was normal without any alcoholic abuse. He was admitted to our hospital with rapidly progressive gait disturbance due to muscle weakness, and sensory disturbance. Neurological examination showed peripheral polyneuropathy with distal dominant muscular weakness and sensory disturbance. Chest X-ray film showed marked cardiomegaly and pleural effusion. Nerve conduction studies showed decreases in the action potentials of both the motor and sensory nerves, with the sensory nerves being more severely affected than the motor nerves. Sural nerve biopsy demonstrated severe axonal degeneration without any inflammatory change. The blood concentration of thiamine (vitamin B1) was slightly decreased below the normal range (19 ng/ml; normal, 20-50), and the serum vascular endothelial growth factor (VEGF) was high (890 pg/ml; normal < 200 pg/ml). Intravenous administration of vitamin B1 (50 mg per day) dramatically improved his symptoms in a few days and the level of VEGF returned to nearly normal. In this gastrectomized patient many years ago, vitamin B1 deficiency neuropathy is warranted in view of a prompt response to thiamine administration. This case suggests that VEGF is involved in the pathogenesis of vitamin B1 deficiency polyneuropathy.

Aged↗
PubMed2003

Myelitis with atopic diathesis: a nationwide survey of 79 cases in Japan.

We recently reported the occurrence of myelitis in patients with atopic disorders and its pathology to be eosinophilic inflammation. Because similar cases have been reported, we conducted a nationwide epidemiological survey (NES) of myelitis with atopy in Japan. We compared the clinicolaboratory features of the 30 NES cases with the 49 cases at Kyushu University Hospital (KU). Although the NES cases were distributed throughout Japan, the NES and KU cases shared common characteristics. We therefore combined all of the cases identified. The average onset age was 35.8+/-13.4 years, and the male/female ratio was 1:0.65. The onset mode was subacute/chronic in half the patients, and stepwise progression or symptom fluctuation was frequent (69.6%). The most common lesion site was determined clinically and by MRI to be the cervical cord, and paresthesia and/or dysesthesia were the most common symptoms initially (74.7%) and throughout the entire course (83.5%). Cerebrospinal fluid (CSF) abnormalities were infrequent and mild. These findings suggest that myelitis associated with atopy has mild but prolonged symptoms and occurs throughout Japan.

Adolescent↗
PubMed2002

Hereditary motor and sensory neuropathy with minifascicle formation in a patient with 46XY pure gonadal dysgenesis: a new clinical entity.

This case report is of a patient with 46XY pure gonadal dysgenesis, who presented with chronic progressive motor and sensory polyneuropathy. The sural nerve biopsy exhibited minifascicle formations accompanied by a marked decrease in myelinated fibers. This is the first report of polyneuropathy with minifascicle formations in 46XY pure gonadal dysgenesis. Because a similar polyneuropathy was recently reported in a case with 46XY partial gonadal dysgenesis, it is possible that these cases represent a new type of hereditary motor and sensory neuropathy associated with gonadal dysgenesis.

Biopsy↗
PubMed2002

Selective matrix metalloproteinase inhibitor, N-biphenyl sulfonyl phenylalanine hydroxamic acid, inhibits the migration of CD4+ T lymphocytes in patients with HTLV-I-associated myelopathy.

Matrix metalloproteinases (MMPs) have been reported to be involved in various inflammatory disorders. Previous studies revealed that MMP-2 and MMP-9 might play important roles in the breakdown of the blood-brain barrier (BBB) in the central nervous system (CNS) of patients with HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). N-Biphenyl sulfonyl-phenylalanine hydroxamic acid (BPHA) selectively inhibits MMP-2, -9 and -14, but not MMP-1, -3 and -7. In the present study, we examined whether or not the selective MMP inhibitor BPHA could inhibit the heightened migrating activity of CD4+ T cells in HAM/TSP patients. The migration assay using an invasion chamber showed that migration of CD4+ T cells in HAM/TSP patients was inhibited by 25 microM BPHA. In addition, the inhibitory ratio of migrating CD4+ lymphocytes was higher in HAM patients compared to normal controls. These results suggest that the selective MMP inhibitor BPHA has therapeutic potential for HAM/TSP.

Adult↗
PubMed2002

Multifocal relapsing-remitting myelitis in a patient with atopic dermatitis: multiple sclerosis or atopic myelitis?

We describe a patient with multifocal relapsing-remitting myelitis. This case had abnormal high intensity lesions in the spinal cord at the cervical and thoracic levels on magnetic resonance imaging (MRI). She had complicated atopic dermatitis and high serum IgE levels, which showed strong sensitivity to mite antigen. These features closely resemble those of atopic myelitis, suggesting that atopic myelitis may develop a relapse with multifocal involvement of the spinal cord, which can mimic multiple sclerosis.

Adult↗
PubMed2002

Minifascicular neuropathy: a new concept of the human disease caused by desert hedgehog gene mutation.

We recently found a patient with 46,XY partial gonadal dysgenesis who presented with polyneuropathy. Sural nerve pathology revealed peculiar findings characterized by extensive minifascicular formation and with a decreased density of myelinated fibers. We found in the patient, a homozygous missense mutation at the initiating codon in exon 1 of the desert hedgehog (DHH) gene, which predicts a failure of translation of the gene. These data demonstrate that DHH is a key molecule in both male gonadal differentiation and perineurial formation in peripheral nerves.

Female↗