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Biomedical subjects

F Umehara

Publications and source records attributed to F Umehara.

At least 73 records · Page 4Linked to original sources
PubMed1993

Dominantly inherited motor and sensory neuropathy with excessive myelin folding complex.

The two patients in a family having the clinical and electrodiagnostic features of hereditary motor and sensory neuropathy (HMSN) are described. The main histological features of sural nerve were segmental demyelination and remyelination with moderate to marked loss of myelinated fibers, and myelin folding complex along all of the large and small myelinated fibers. These features appeared morphologically similar to those observed in HMSN with excessive myelin outfolding, or globular neuropathy. Southern blot analysis suggests that there were neither duplication nor deletion of the peripheral myelin protein-22 gene in the patients. The presented two patients may be a rare form of dominantly inherited HMSN with myelin folding complex.

Biopsy↗
PubMed1993

An autoaggressive process against bystander tissues in HTLV-I-infected individuals: a possible pathomechanism of HAM/TSP.

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a well-defined clinico-pathological entity in which the virus infection and the host immune responses are involved in the pathomechanism. It is generally agreed that the virus infection precedes the development of HAM/TSP and the infection is persistent during the course of disease. However, what plays the key role for the development of HAM/TSP remains to be elucidated. In this article, we emphasise the importance of the unique nature of HTLV-I-infected cells, which may have a potential ability to produce viral antigens outside of the blood flow, and we also review a variety of evidences supporting the following proposal. In our hypothesis, the supply of infected T cells from blood flow to central nervous system (CNS) is primary for the development of CNS lesions. Both anatomically determined hemodynamic conditions and adhesion molecule-mediated interactions between circulating infected T cells and endothelial cells may contribute to the localization of the main lesions. Following an induction of the HTLV-I antigens on the surface of infected T cells in CNS compartment, expansion of the responses of immunocompetent T cells against the viral proteins may result in CNS tissue damage which may be mediated by released cytokines. This is the first attempt to implicate a bystander damage mechanism in a human disease as an essential pathomechanism.

Autoimmunity↗
PubMed1993

Immunocytochemical analysis of the cellular infiltrate in the spinal cord lesions in HTLV-I-associated myelopathy.

Immunocytochemical staining of spinal cords from five autopsied patients with HAM/TSP was performed using a panel of monoclonal antibodies reactive with T cells. T cell subsets, B cells, macrophages, natural killer cells, IL-2 receptor-positive cells, and HLA-ABC and HLA-DR. In the spinal cords of patients with a shorter duration of illness, CD4+ cells, CD8+ cells and macrophages were evenly distributed in active-chronic inflammatory lesions. In striking contrast, we noted the predominance of CD8+ cells over CD4+ cells in the inactive-chronic inflammatory lesions of patients with longer duration of illness. Natural killer cells, IL-2 receptor-positive cells and B cells were only rarely present in both the active-chronic and inactive-chronic lesions. HLA-ABC was positive in endothelial cells and infiltrating mononuclear cells, and HLA-DR was positive in endothelial cells, microglia and infiltrating mononuclear cells. This study suggests that immune responses in the spinal cord lesions of HAM patients gradually change along with the duration of illness.

Aged↗
PubMed1993

Werner's syndrome associated with spastic paraparesis and peripheral neuropathy.

A Werner's syndrome patient with spastic paraparesis and polyneuropathy had slowing of central and peripheral nerve conduction. Sural nerve biopsy revealed a significantly higher frequency of demyelination and remyelination and a loss of myelinated fibers. These data suggest that the central and peripheral nervous systems are affected in Werner's syndrome.

Adult↗
PubMed1993

[A case of Werner syndrome associated with spastic paraparesis and peripheral neuropathy].

A 33-year-old woman, whose parents were consanguineously married, was admitted to our hospital because of progressive difficulty in walking and hoarseness in speech. She had been in good health as a child, at age 16 ulcerations appeared on the skin of feet, and have been recurrent. AT age 22, bilateral cataracts were removed. From the age of 26 years, the deformities in the toes and fingers worsened and she had difficulty in walking. At age 32, hoarseness was noticed. The patient was a diminutive woman and the skin was dry, thin and hyperpigmented. The neurological examination revealed mental retardation, spastic paraparesis and polyneuropathy. Electrophysiological studies revealed a slowing of central and peripheral nerve conduction. Sural nerve biopsy revealed a significantly higher incidence of de- and remyelination and a loss of myelinated fibers. These data suggest that the central and peripheral nervous systems are affected in Werner syndrome.

Adult↗
PubMed1991

Polyneuropathy induced by m-tolyl methyl carbamate intoxication.

A 55-year-old woman who attempted suicide by ingesting 200 ml of m-tolyl methyl carbamate (MTMC) is reported. She was comatose for 3 days and, upon recovery, had notable paraesthesia in her lower limbs and difficulty in walking. Neurological examination revealed sensorimotor polyneuropathy. Sural nerve biopsy revealed marked axonal degeneration with a moderate decrease of myelinated fibres.

Carbamates↗
PubMed1991

[Juvenile parkinsonism in monozygotic twins].

A pair of monozygotic twins concordant for juvenile Parkinsonism are described. These twin sisters have lived together until 18 years old. Twin A noted tremor in the right hand and right-sided stiffness and slowness at the age 20. Initially, a marked improvement was shown with L-dopa treatment. However, one year after the beginning of treatment, dopa-induced dyskinesia appeared. Twin B noted tremor and right-sided stiffness and basal ganglia calcification in both patients. These twin patients suggest that genetic factors may play an important role in the cause of juvenile Parkinsonism.

Adult↗
PubMed1991

[A case of scapuloperoneal atrophy with rigid spine having lobulated fibers in muscle biopsy].

The patient, a 52-year-old male, noticed abnormalities on walking at about 20 years of age, followed by slowly progressive muscle weakness of arms and neck. The family history was negative. He showed muscular atrophy and weakness with a preferential involvement of the scapular, arms and peroneal muscles. Deep tendon reflexes were absent. He had a limited range of motion in the spine, but the onset was unclear. Creatine kinase (CK) was elevated (324 IU/L) and the EMG study showed myogenic pattern. Muscle biopsy was obtained from the biceps brachii muscle; on NADH dehydrogenase stain, there was subsarcolemmal increase in the oxidative enzyme activity showing "lobulated fiber" mostly seen in type 1 fibers. On electron-microscopy, the sub-sarcoplasmic areas which had high NADH activity, contained many mitochondria and glycogen particles. However, iodine-glycogen complex spectrum analysis pattern and debranching enzyme activity were normal. CT scan revealed low density in the paravertebral muscles, suggesting degeneration. This is a rare type of scapuloperoneal atrophy different from Emery-Dreifuss syndrome, rigid spine syndrome and FSH type muscular dystrophy.

Adult↗
PubMed1990

An autopsied case of the Crow-Fukase syndrome: a neuropathological study with emphasis on spinal roots.

An autopsied case of the Crow-Fukase syndrome is reported. Neuropathological findings were as follows: (1) in the sural nerve, there was marked decrease of large and small myelinated fibers. Myelinated fibers showing axonal degeneration and segmental demyelination and remyelination were moderately increased. (2) In the lumbar spinal roots, myelinated fibers showing segmental demyelination and remyelination were frequently observed. The density of myelinated fibers of the ventral root was less at the dural site than the spinal site, while that of the dorsal roots was less at the spinal site than the dural site. (3) In the dorsal root ganglion, there were Nageotte's residual nodules and satelliotosis; (4) in the lumbar and thoracic spinal cord, there was pallor of the dorsal column; and (5) nerve cells showing central chromatolysis were frequently observed in the spinal anterior horn cells. Segmental demyelination and remyelination in the spinal roots and loss of myelinated fibers with axonal degeneration in the sural nerve are main neuropathological features of this syndrome.

Aged↗
PubMed1990

Experimental autoimmune encephalomyelitis in the maturing central nervous system. Transfer of myelin basic protein-specific T line lymphocytes to neonatal Lewis rats.

We analyzed the effects of myelin basic protein (MBP)-specific encephalitogenic T line cells in neonatal syngeneic recipients before and after formation of central nervous system myelin. Lewis rat pups (postnatal days 0, 1, 2, 4, 8) were injected intraperitoneally with MBP-specific T cell line in doses which cause clinical and histologic changes of experimental autoimmune encephalomyelitis (EAE) in adult rats. We correlated the susceptibility to transferred EAE with the developmental appearance of MBP as demonstrated by immunohistochemical staining. MBP was barely demonstrable until postnatal day 2 but became definitely apparent on postnatal day 4. All newborn rats that were injected on postnatal day 0, 1, 2 failed to develop any apparent clinical signs, but histologically some recipients displayed slight inflammatory cell infiltration of the meninges and subpial lesions limited to the lower spinal cord. In striking contrast, rats that were injected on postnatal day 4 or 8, developed clinical signs and, in particular, many of the older recipients became moribund. Histologically, these animals displayed marked inflammatory cell infiltrations and white matter destruction within the spinal cord. Clinical and histologic severity clearly increased with the recipient's age. Histologically, there were some differences between adult rat EAE and newborn rat EAE. In contrast to adult rat EAE which displayed grey and white matter involvement with marked perivascular mononuclear cell infiltrations, newborn rat EAE typically showed very severe changes with edema formation selectively in the white matter and the cellular infiltrates were dominated by polymorphonuclear cells and macrophages. Newborn T line-mediated EAE thus strikingly resembles hyperacute EAE induced in immunocompromised (irradiated) recipients.

Animals↗
PubMed1990

[A case of the primary mediastinal seminoma invading into the extradural space of the thoracic spine].

Seminomatous germ cell tumors can arise as primary mediastinal malignancies in the mediastinum without involving the testis. The usual location is the superior mediastinum and histologically it is identical to the testicular seminoma. Here we report a case of extradural spinal cord tumor by primary mediastinal seminoma. The patient, 24 year old male, was evaluated for complaints of severe back pain associated with dysesthesia in lower limbs. He was operated as primary mediastinal seminoma when he was 21 years old. On admission, physical examination was unremarkable except for hypereflexia in lower extremities. The testis were normal. Chest radiography and computed tomography revealed a large mediastinal mass which invaded into the extradural space of the thoracic spine. He had a laminectomy of the thoracic spine and was treated by the radiation therapy and chemotherapy. This is the first report showing the neuroradiological findings of the extradural spinal cord tumor by primary mediastinal seminoma.

Adult↗