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Biomedical subjects

S Imura

Publications and source records attributed to S Imura.

At least 19 recordsLinked to original sources
PubMed1999

Hereditary sensory neuropathy with deafness and dementia: a clinical and neuroimaging study.

We describe three sibling patients with autosomal dominantly inherited sensory neuropathy, sensorineural hearing loss and dementia. The features of cognitive-behavioral deficits in the patients, including executive dysfunction, apathy, indifference and inattention, were consistent with a frontal lobe dysfunction. Magnetic resonance imaging showed a diffuse brain atrophy. A fluorodeoxyglucose positron emission tomography in one patient and a single photon emission computed tomography in another demonstrated a glucose hypometabolism or a hypoperfusion in the medial frontal and thalamic regions. Primary frontal involvement or frontal dysfunction secondary to thalamic lesions may contribute to the nature of dementia in these patients.

Deafness↗
PubMed1999

Nonlinear three-dimensional finite element analysis of newly designed cementless total hip stems.

We designed 2 new types of proximally coated stems (the FMS and FMS-anatomic) based on the endosteal geometry of femora with congenital dislocation or dysplastic hip. The FMS was symmetric while the FMS-anatomic was asymmetric. We compared the proximal fit and fill to the femoral canal, contact stress, relative motion, and load transfer to the femur of 5 stems (FMS, FMS-anatomic, Omnifit, Omniflex, and individual stem) using three-dimensional computer simulation and finite element analysis. The FMS and FMS-anatomic showed a significantly greater fit and fill than conventional stems. The dispersion of the contact stresses and reduction of relative motions in the proximal area were the best in the FMS-anatomic compared to other stems with the exception of the individual stem. In addition, the FMS-anatomic stem transferred most of the load to the proximal femur. Our results suggest that the FMS-anatomic should provide better biomechanical stability at least in the early postoperative period.

Arthroplasty, Replacement, Hip↗
PubMed1998

Histological investigation of spinal cord lesions in the spinal hyperostotic mouse (twy/twy): morphological changes in anterior horn cells and immunoreactivity to neurotropic factors.

We examined the morphology of spinal accessory motoneurons and immunoreactivity to neurotrophins, brain-derived neurotropic factor (BDNF) and neurotrophin (NT)-3, as well as the presence of reactive astrocytosis in 70 tiptoe walking Yoshimura (twy) mice that develop calcification at C1-C2 vertebral level compressing the spinal cord. At the level of compression, the area of neuronal soma and total length of dendrites of wheat germ agglutinin-horseradish peroxidase (WGA-HRP)-labelled accessory motoneurons in the medial cell pool decreased significantly with decrement in motoneuron population, relative to the control. In contrast, at sites rostral to the compressive lesion, a significant enlargement of the neuron soma and dendritic elongation were noted, associated with increased motoneuron population and decreased transverse area of the cord at the level of compression. At this site, enhanced BDNF and NT-3 immunoreactivities were evident in the anterior horn cells. In mice with a more severe degree of compression, astrocyte-like cells showing BDNF immunoreactivity became abundant and axons in the anterior column demonstrated a marked NT-3 immunoreactivity. Our results suggest increased functional activity of anterior horn cells at levels rostra] to the site of compression. We speculate that the presence of BDNF and NT-3 in neurons and astrocyte-like cells is proportionate to the severity of chronic mechanical compression and may contribute to the heterotropic neuronal reserve and survival.

Animals↗
PubMed1998

Prosthetic knee Candida parapsilosis infection.

We report a 77-year-old man who developed Candida parapsilosis infection following total knee arthroplasty. Knee joint effusion was noted 2 weeks after surgery, and repeated cultures of aspirated fluid established the diagnosis of Candida parapsilosis infection 4 weeks after surgery. Treatment consisted of debridement and lavage of the involved joint together with continuous irrigation with fluconazole for 4 weeks, followed by oral fluconazole for another 6 months. At 3 years follow-up, the patient was doing well and radiological examination of the affected knee showed a firm attachment of the prosthesis. We suggest that early identification of the causative organism followed by continuous irrigation and use of appropriate antifungal medication may prevent joint instability and spares the removal of the prosthesis.

Aged↗
PubMed1998

Cervical myeloradiculopathy with entrapment neuropathy: a study based on the double-crush concept.

In an attempt to formulate a standardised approach to the diagnosis and management of patients with the double-crush syndrome, we reviewed 65 surgical cases (39 men and 26 women) with cervical myeloradiculopathy associated with entrapment neuropathy in the arm by examining the clinical features, results of nerve conduction velocity studies and distribution of the vertebral levels of compression. Fifty-three patients (average age, 43 years) presented with a carpal tunnel syndrome at the wrist and cervical lesions (41 with spondylosis and 12 with ossified posterior longitudinal ligament), while 12 had a cubital tunnel syndrome at the elbow with cervical lesions (eight with spondylosis and four with ossification of the posterior longitudinal ligament). In the former group, the lesions were found mostly at C5-6 and C6-7 levels, while in the latter group involvement of C6-7 was frequently observed. Two patients in each group required additional cervical decompression after carpal or cubital tunnel release. A retrospective review of our patients suggested that it is reasonable to pursue an accurate diagnosis followed by treatment based on individual neurological and electrophysiological findings, but taking into consideration the significant level of physical impairment associated with cord compromise, we believe that it may be reasonable to perform a cervical decompression rather than peripheral nerve release in such cases. Our findings suggest that one should be aware of a double-crush during examination of patients complaining of neck and hand problems.

Adult↗
PubMed1998

Solitary plasmacytoma of the spine associated with neurological complications.

We report eight patients with a solitary plasmacytoma of the spine associated with neurological complications. The patients included five men and three women with an average age at presentation of 59 years (range, 47 to 73 years). The tumour was confined to the thoracic spine in six cases, cervical spine in one and lumbar spine in one. Duration of symptoms ranged from 2.5 to 22 months. Treatment consisted of a combination of radiotherapy, melphalan and surgery. One patient progressed to multiple myeloma 7 years after surgery. Surgical treatment (anterior surgery in three cases and posterior surgery in five) produced neurological improvement in all patients. We stress the importance of an early diagnosis followed by appropriate treatment including surgery for this clinical entity and long-term follow-up to detect a disseminated disease.

Aged↗
PubMed1998

Identification of the gene loci that predispose to rheumatoid arthritis.

We have searched the human genome for genes that predispose to rheumatoid arthritis (RA) using fluorescence-based microsatellite marker analysis and affected sib-pair linkage study. A panel of 41 Japanese families, each with at least two affected siblings, was typed for genome-wide 358 polymorphic microsatellite marker loci. Markers were amplified by the PCR using fluorescence-tagged primers and sized based on the difference of CA repeats on DNA. Linkage analysis was made using maximum lod score (MLS). The MLS for D1S214 and D8S556 was 3.27 and 3.33, while the MLS for the HLA-DRB1 region was <3.0. According to detailed analysis by single-point analysis using MAPMAKER/SIBS, the MLS for D1S253 and D1S214 was 3.77 and 3.58. The MLS by multipoint analysis was 6.13 for D1S253. The MLS for D8S556 by single-point analysis was 4.20. The MLS for DXS1232 was 2.35 by single-point analysis, whereas the MLS for the region 2 cM right to DXS1232 and the region between DXS1227 and DXS1200 was 3.03 and 2.93 by multi-point analysis. Three principal chromosome regions of linkage, D1S253/214, D8S556 and DXS1232, have been identified which we call RA1, RA2 and RA3 for RA disease loci.

Arthritis, Rheumatoid↗
PubMed1998

Relationship between gait and clinical results after high tibial osteotomy.

Thirty-two patients with primary osteoarthritis of the medial compartment of the knee were studied prospectively to assess the relationship between clinical results, limb alignment, and adduction moment of the knee. Clinical and radiographic examination and gait analyses were performed preoperatively and repeated at 6 months and at 1, 3, and 6 years after high tibial osteotomy. The preoperative peak adduction moment was high in 25 patients and low in seven. In both groups, the adduction moment of the knee decreased at 6 months after surgery but increased after that period. Alignment of the affected knee in both groups remained valgus after surgery (average femorotibial angle, 167 degrees-169 degrees). Clinical outcome in both groups improved after surgery and remained unchanged after 1 year. The peak adduction moment of the knee for the whole group significantly correlated with alignment and foot angle before and 6 years after surgery but did not correlate with stride length and walking velocity. In addition, only alignment was associated significantly with clinical results at 6 years. These results suggest that the preoperative peak adduction moment of the knee does not correlate with clinical or radiographic outcomes of high tibial osteotomy, provided sufficient valgus alignment is achieved at surgery.

Aged↗
PubMed1998

Vertical transmission of human immunodeficiency virus type 1 in Japan, 1989-1997: presence of two subtypes B and E with subtype E predominance. National Cooperative Study Investigators on Vertical Transmission of HIV-1.

A collaborative group for studying vertical transmission of human immunodeficiency virus (HIV)-1 in pregnant women and their babies was established in Japan in 1989. Forty-two infants, including 13 HIV-1-infected, 25 uninfected and four of undetermined status and 15 control children born to HIV-1 negative mothers were diagnosed and followed from birth to 1.5 years. All strains from HIV-positive infants were either clade E (eight infants, 61.5%) or B (five infants, 38.5%) according to DNA sequencing specific for the HIV-1 C2-V3 region. The 42 mothers with HIV-1 were women with sexual-risk behavior from all regions, but were concentrated in the Kanto District. In this group of HIV-infected children, there was no significant difference between the transmissibility of their mother's clade E and B viruses. Eight (61.5%) of the 13 virus-infected babies were Japanese and five (62.5%) of the eight were positive for HIV-1 clade E. The V3 loop region of the clade E virus of the babies was conserved but approximately 60% of the sequences which showed a substitution of aspartic acid by asparagine at position 29. The results suggest that HIV-1 clade E may be predominant in vertical transmissions and are phenotypically different from HIV-1 in persons with various other risk behaviors in Japan.

Consensus Sequence↗
PubMed1997

Vertebral lesions associated with palmoplantar pustulosis.

Spinal lesions were reviewed in 9 patients (3 men and 6 women) who presented with palmoplantar pustulosis. Cervical lesions were found in 3 patients and lumbosacral involvement in 7. The duration of disease averaged 4.8 years. Seven patients had associated sterno-costo-clavicular hyperostotic lesions, and all showed abnormalities in blood tests which suggested chronic inflammation. Vertebral lesions were assessed as a spondylodiscitis type in 4, single level syndesmophyte-forming type in 1, multiple hyperostosis type in 4, and an ivory vertebra type in 1. Five patients were treated conservatively, and 4 with progressive spondylodiscitis type lesions underwent curettage and anterior interbody fusions. At follow-up, all patients improved in both spinal and cutaneous presentations, and 4 who underwent surgery and 1 with tonsillectomy attained complete cure. The vertebral manifestations of palmoplantar pustulosis may vary, but rapidly progressive lesions need surgery for favourable early improvement from the vertebro-cutaneous symptom complex.

Female↗
PubMed1997

Stress fracture of the femoral component in total knee replacement: a report of 3 cases.

We report 3 cases of stress fracture of the femoral component (small size Whiteside Ortholoc II) in total knee replacements which occurred at 32, 52, and 73 months after operation. The site was at the junction between the medial posterior bevelled surface and the posterior flange. The most likely cause of failure is due to the thinness of the metal at this point.

Aged↗
PubMed1997

The tarsal tunnel syndrome: evaluation of surgical results using multivariate analysis.

Thirty-four patients with the tarsal tunnel syndrome were treated by decompression of the posterior tibial nerve. The condition was bilateral in 3 cases. There were 9 men and 25 women with an average age at operation of 41 years. The average follow up was for 3.8 years. Multivariate analysis showed that the outcome is influenced, in order of importance, by fibrosis around the nerve, the preoperative severity of the condition, a history of sprained ankle, worker's compensation, a long history, and heavy work. The results were favourable when there was a short history, the presence of a ganglion, no sprains, and light work. Measurement of the terminal latency of the medial plantar nerve was valuable in assessing recovery. The precise cause of the syndrome and its effect on treatment should be considered before operation.

Adolescent↗
PubMed1997

Three-dimensional topographic analysis of spinal accessory motoneurons under chronic mechanical compression: an experimental study in the mouse.

We investigated the effect of chronic mechanical compression of the cervical spinal cord on the number of spinal accessory motoneurons in 25 tiptoe-walking Yoshimura mice. The animals had calcified deposits in the atlantoaxial membrane at the C1-C2 vertebral level, compressing the spinal cord posterolaterally. Motoneurons of the spinal accessory nerve between C1 and C5 segments were labelled using wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected into the sternocleidomastoid muscles. The counted cells were processed into a three-dimensional computer display to analyse the cytoarchitectonic changes caused by external cord compression. The number of WGA-HRP-labelled spinal accessory motoneurons was significantly reduced on the affected side. The number of motoneurons in compromised C2 and C3 cord segments correlated linearly with the extent of mechanical compression, but no such relationship was present on the contralateral side. There was an increase in the number of WGA-HRP-labelled spinal accessory motoneurons in the medial cell pools of the anterior grey horn at a level most rostral to the compression, and in the ventrolateral cell pools at levels immediately rostral to the compression. Our findings suggest that the spinal accessory motoneurons translocate rostral to the area of external compression in order to avoid mechanical injury.

Animals↗
PubMed1997

Plasticity of the spinal cord contributes to neurological improvement after treatment by cervical decompression. A magnetic resonance imaging study.

To investigate the relationship between morphological plasticity of the spinal cord and neurological outcome after surgery for compressive lesions, we correlated the transverse area of the cervical spinal cord measured by transaxial magnetic resonance imaging (MRI) obtained during the early postoperative period (1-6 months) with neurological function assessed at a median postoperative follow-up period of 2.5 years. Measurements on MRI in 56 patients (35 men and 21 women) included evaluation of the cross-sectional area of the cervical cord and the subarachnoidal space at the level of decompression. The transverse area of the cervical cord increased by 30 to 62% postoperatively and that of the subarachnoidal space by 57 to 95%. Neurological improvement was noted in all patients and averaged 63% in our assessment scale. Expansion of the cervical cord during the early postoperative period correlated significantly with the late postoperative neurological status (P = 0.009). Our results suggest that an increase in the cross-sectional area of the cervical spinal cord, representing spinal cord morphological plasticity, is a significant factor in determining the late neurological improvement following decompressive surgery.

Adult↗
PubMed1997

Ganglion cyst of the posterior longitudinal ligament causing lumbar radiculopathy: case report.

We describe a man aged 26 years who presented with a neurological syndrome, which was found on lumbar radioculopathy to be due to a ganglion cyst originating from the posterior longitudinal ligament. Based on MRI findings, cystic lesion was suspected, a round lesion at L4 level with no connection to the adjacent facet or to the dura matter. During surgery, a liquid-containing cystic lesion was found to originate from the posterior longitudinal ligament at L4 level. The resected cyst was diagnosed histologically as a ganglion cyst. A complete cure was established after surgery and no recurrence was noted at a follow-up 1.7 years postoperatively. A ganglion cyst of the posterior longitudinal ligament should be considered in the differential diagnosis of a cyst in the lumbar region causing neurological complications.

Adult↗
PubMed1997

Three-dimensional computed tomography for evaluation of cervical spinal canal enlargement after en bloc open-door laminoplasty.

We evaluated the use of three-dimensional (spiral) computed tomography (CT) to assess widening of the bony cervical spinal canal following en bloc open-door C3-C7 laminoplasty in 31 patients. Measurements were performed using a computerised image processing system. The increment in the anteroposterior spinal canal axis and volume of the bony spinal canal was investigated in relation to changes in cervical spine lordosis as well as postoperative neurological improvement. Neurological follow-up averaged 2.6 years (range, 1 to 7 years). A mean increase of 42% was observed in the anteroposterior axis of the canal between C3 to C7 after surgery, while the volume increased by 45%. Postoperatively, cervical spine lordosis correlated with increments in the volume of the enlarged bony canal rather than the anteroposterior axis. Postoperative neurological improvement correlated significantly with the increase in the canal volume. Our results indicate that spiral CT is useful for the assessment of the magnitude of cervical canal enlargement and evaluating the space available for the spinal cord following the relief of compression.

Adult↗
PubMed1997

Use of osteonics UHR hemiarthroplasty for fractures of the femoral neck.

A clinical and radiographic study of bipolar hip arthroplasties was performed for fractures of the femoral neck. All patients were treated with the Osteonics UHR system. Clinical results were evaluated in 77 patients (77 hips) who were observed for an average of 4.8 years (range, 2-10 years). At the latest followup, 67 (87%) patients were rated as having a good or excellent outcome according to the Hospital for Special Surgery hip rating system. Clinical ratings in patients treated with cementless UHR were similar to or better than those of patients with cemented UHR. Hip dislocation occurred in only 3 (2.3%) patients, in whom the hip joint was reduced by a closed procedure without inducing disassembly of the prosthetic components. None of the patients had definitive acetabular erosion. The motion of the outer head was evaluated radiographically in 63 patients in weightbearing and non-weightbearing conditions, 3 to 108 months after surgery. The relative motion at the 2 sites of articulation of the outer head had stabilized by 3 months after surgery and subsequently remained unchanged. The authors' findings indicate that UHR hemiarthroplasty of the femoral head is a reliable treatment for fractures of the femoral neck.

Activities of Daily Living↗