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Biomedical subjects

Y Maezawa

Publications and source records attributed to Y Maezawa.

At least 37 records · Page 2Linked to original sources
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

Extraforaminal lumbar disc herniation at two contiguous intervertebral levels.

We describe two unusual surgical cases who presented with extraforaminal lumbar disc herniation that occurred at two adjacent vertebral levels simultaneously and unilaterally. Magnetic resonance imaging and selective nerve root infiltration followed by radiculography helped to outline the herniated disc material. Lateral fenestration and microsurgical foraminal widening of the affected vertebral levels allowed a complete and safe relief of the compressed nerves.

Female↗
PubMed1997

Potential role of streptozotocin in enhancing ossification of the posterior longitudinal ligament of the cervical spine in the hereditary spinal hyperostotic mouse (twy/twy).

We investigated the effects of streptozotocin-induced diabetes mellitus on ossification of the posterior longitudinal ligament (OPLL) in the murine cervical spine. A genetically-bound spinal hyperostotic mouse, the tip-toe walking Yoshimura (twy) mouse, was used in these experiments. Histological examination showed that streptozotocin enhanced membranous and enchondral ossification of the posterior longitudinal ligament of the cervical spine, particularly in the area of the ligamentous enthesis. It also increased the number of alkaline phosphatase-positive osteoblast-like mesenchymal cells particularly around the enthesis, while the number of such cells was less in control twy mice and ICR mice treated with streptozotocin. The area of OPLL subsequently increased in size in streptozotocin-treated twy mice. We suggest that streptozotocin-induced diabetes enhances OPLL in the genetically-bound spinal hyperostotic mouse (twy/twy).

Age Factors↗
PubMed1997

Herniated cervical intervertebral discs: histological and immunohistochemical characteristics.

We examined the histological and immunohistochemical changes within and around herniated cervical intervertebral discs. A total of 28 herniated discs were harvested en bloc during anterior decompressive surgeries and examined together with the surrounding tissues. The presence of herniated discs correlated with the degeneration of cartilaginous endplate and torn annulus fibrosus. Formation of new blood vessels around the herniated discs was detected, using von Willebrand factor antibody, in seven (25% of all) uncontained hernias and eight (38%) contained hernias. Immunohistochemical studies using specific antibodies showed the presence of cells positive for matrix metalloproteinase-3 (chondrocytes), CD68 (macrophages and monocytes), and interleukin-1 beta (endothelial cells), in cervical disc hernias. Our results suggested that the magnitude and degree of immunohistochemical tissue reaction in cervical disc herniation correlate with the extent as well as location of herniated disc material.

Adult↗
PubMed1996

Lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy: a magnetic resonance imaging study.

We investigated lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy. Fifty-five patients (32 men and 23 women) were studied, with an average follow-up of 2.4 years. Radiological examination included evaluation of lordosis of the cervical spine and spinal cord, degree of enlargement of bony spinal canal, and the magnitude of posterior cord migration. We also correlated these changes with neurological improvement. Postoperatively, there was an average of 5% loss of cervical spine lordosis (P > 0.01) on radiographs and 12% reduction in the lordotic alignment of the spinal cord (P > 0.05) on magnetic resonance imaging. Postoperatively, the size of the bony spinal canal increased by 48%. Posterior cord migration showed a significant correlation with the preoperative cervical spine and spinal cord lordosis (P < 0.05). Thirty-seven (67%) patients with neurological improvement exceeding 50% showed significant posterior cord migration following laminoplasty compared with those demonstrating less than 50% improvement (P = 0.01). Our results suggest that a significant neurological improvement is associated with posterior cord migration after cervical laminoplasty.

Adult↗
PubMed1996

Quantitative analysis of the spinal cord motoneuron under chronic compression: an experimental observation in the mouse.

We investigated quantitative changes in spinal cord motoneurons following chronic compression using a mouse model of cervical cord compression. Twenty-five tip-toe-walking Yoshimura (twy) mice with calcified mass lesions compressing the spinal cord posterolaterally at the C1-C2 vertebral levels were compared with five Institute of Cancer Research (ICR) mice that served as controls. Spinal cord motoneurons in the anterior grey horn between the C1 and C3 spinal cord segments were Nissl-stained and counted topographically and then analysed in relation to the extent of spinal cord compression. The number of motoneurons in C1-C3 spinal cord segments decreased significantly with a linear correlation with the transverse area of the spinal cord when the cord was compressed to 50-70% of control values. A significant reduction in the number of motoneurons occurred at the C2-C3 spinal cord segment compressed at the C1-C2 vertebral level. In contrast, at the level rostral to the C1 vertebra, the number of motoneurons increased significantly in proportion to the magnitude of compression. The current study demonstrates that a number of neurons, morphologically consistent with anterior horn cells, were observed at a rostral site absolutely free of external compression where no such cells normally exist.

Animals↗
PubMed1996

Lumbosacral dumb-bell neurilemmoma approached by microsurgical interlaminar foraminotomy. A case report.

The case history of a patient with a dumb-bell neurilemmoma arising from the L5 nerve root is described. The tumour extended into the outlet of the neural foramen at L5-S1 on the left and was also compressing the dural sac and the S1 nerve root. A limited laminotomy at L4-5 and L5-S1, with preservation of the neural arch, was followed by microsurgical medial foraminotomy at L5-S1 which allowed visualisation of the nerve root and enucleation of the tumour. The technique maintains stability of the posterior elements and spinal movement, and is recommended for the removal of this type of tumour.

Adult↗
PubMed1996

Microsurgical nerve root canal widening without fusion for lumbosacral intervertebral foraminal stenosis: technical notes and early results.

We describe a technique for microsurgical widening of the nerve root canal in the lumbosacral spine. We also report our early results in 31 patients (19 men and 12 women; average follow-up, 3.2 years) with such foraminal stenosis but without osseous defects in the pars interarticularis and/or spondylolisthesis. The affected nerve root was decompressed by interlaminar medial foraminotomy followed by lateral laminotomy and foraminotomy using a microsurgical technique. The procedure aimed at preserving bony continuity of the pars interarticularis and segmental motion. Neurological results showed a favourable improvement of radicular symptoms and of intermittent claudication. The need for segmental fusion at the operated segment was excluded in 30 patients, but one patient subsequently required a transpedicular screw procedure with bone grafting. We recommend the present technique for effective decompression of the nerve root within the neural foramen, simultaneously maintaining lumbar spine mobile function.

Action Potentials↗
PubMed1996

Development of hydrocephalus after cervical laminoplasty for ossification of the posterior longitudinal ligament: case report.

We report a 69-year-old woman who developed serious hydrocephalus after cervical laminoplasty for ossification of the posterior longitudinal ligament. The patient presented with approximately 50% spinal canal compromise pertaining to ossified lesion at C5 and C6 levels and subsequently underwent a C3-C7 open-door laminoplasty, followed by uneventful neurological recovery until 2 weeks postoperatively. Despite a favourable postoperative course, she presented with serious symptoms and signs of intracranial hypertension about 3 weeks after surgery. Computed tomography demonstrated the appearance of marked hydrocephalus, with no explainable cause. A ventriculoperitoneal shunt followed by removal of subdural fluid in the suboccipital fossa resulted in resolution of the clinical symptoms and of the hydrocephalus. It is important to be aware of the very rare occurrence of such intracranial neurological compromise after a cervical laminoplasty operation for long-standing ossification of the posterior longitudinal ligament.

Aged↗
PubMed1996

Spinal cord evoked potential monitoring for cervical and thoracic compressive myelopathy.

Spinal cord evoked potentials (SCEPs) were recorded epidurally in 95 surgical cases of cervical and/or thoracic compressive myelopathy. Abnormal SCEPs occurred in 91% of the patients with cervical myelopathy and in all with thoracic involvement at the levels suspected to be responsible for neurological damage. Abnormal SCEPs correlated significantly with the severity of spinal cord compromise and symptoms, such as myelopathy. It was not possible to predict postoperative neurological improvement on the basis of the preoperative SCEP findings alone, but better neurological improvement after surgery was closely associated with early recovery of intra- and postoperative SCEPs. Epidural SCEPs are therefore useful in making a level-specific diagnosis, especially in the patient with multilevel vertebral involvement, and in assessing the severity of neurological compromise and surgical outcome to some extent.

Adult↗
PubMed1996

Posterior limbus vertebral lesions causing lumbosacral radiculopathy and the cauda equina syndrome.

This report reviews our experience with spinal decompression for posterior limbus vertebral lesions or osteocartilaginous vertebral corner defects in the lumbar spine in 29 children and young adults. There were 19 male and 10 female patients with a mean age of 16.5 years (range, 9 to 24 years). Twenty-four patients were involved with various athletic activities. Clinical presentation included low back pain with a variable degree of radiculopathy in 25 patients and a cauda equina syndrome in four. The level of the affected spinal area was L1-2 in one patient, L2-3 in one, L3-4 in seven, L4-5 in 17, and L5-S1 in three. The preoperative imaging workup showed lateralised "non-calcified' or 'calcified' limbus vertebral defects in 13 patients and centrally displaced lesions in 16 patients. All patients underwent posterior spinal decompression with a slightly extended laminotomy, except for three patients who had a subsequent posterolateral fusion. All of the patients consequently returned to practice their favourite preoperative sport and lifestyle, but five discontinued their previous sports. We suggest that patients with posterior limbus vertebral lesions require careful diagnosis and therapy that are different from those with an ordinary lumbar disc herniation.

Adolescent↗
PubMed1996

Association of restriction fragment-length polymorphisms in the alcohol dehydrogenase 2 gene with alcoholic brain atrophy.

Alcohol abuse can induce brain atrophy, but it only occurs in some alcoholics. To investigate whether genetic polymorphism of alcohol-metabolizing enzymes [including alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH)] was related to alcoholic brain atrophy, we determined restriction fragment-length polymorphisms of the ADH2 and ALDH2 genes in 77 male alcoholics. Computed tomography was used to determine the severity of brain atrophy. Digestion with MaeIII and MboII after polymerase chain reaction amplification showed that the ADH2(1) gene frequency was significantly higher in patients with brain atrophy than in those without brain atrophy (chi 2 = 9.274, p < 0.01), whereas no significant association was observed between brain atrophy and the ALDH2 gene Multivariate analysis (including age, total alcohol intake, liver cirrhosis, and ADH2 genotype) showed that the ADH2(1)/ADH2(1) genotype was associated with alcoholic brain atrophy. These findings suggest that the ADH2(1) allele may be associated with alcoholic brain atrophy.

Adult↗
PubMed1996

Effects of cimetidine on blood ethanol levels after alcohol ingestion and genetic polymorphisms of sigma-alcohol dehydrogenase in Japanese.

Administration of cimetidine, an H2-receptor antagonist increases blood alcohol concentrations. This has been attributed to decreased gastric first-pass metabolism of ethanol caused by cimetidine's inhibitory effect on gastric alcohol dehydrogenase (sigma-ADH) activity. Molecular studies on sigma-ADH showed that a point mutation might occur at position 287 (G --> T) of the sigma-ADH gene in Japanese deficient type of sigma-ADH activity. To clarify the relationship between first-pass metabolism of ethanol and polymorphism of sigma-ADH, we analyzed the nucleotide sequence at positions 287 and 294 of sigma-ADH in 11 individuals who were administered ethanol orally before and after treatment with cimetidine. Higher blood ethanol levels after cimetidine administration were found in 4 of 11 cases (group A), whereas high blood ethanol levels were observed in 7 of 11 cases (B group), irrespective of cimetidine administration. Genetic polymorphisms at position 287 and 294 were not observed in all subjects. Even in 59 Japanese men with various alcoholic liver diseases, no polymorphisms at position 287 were observed by restriction-length polymorphisms with Avail digestion after polymerase chain reaction.

Adult↗
PubMed1995

Flexibility and alignment of the cervical spine after laminoplasty for spondylotic myelopathy. A radiographic study.

The long term effects of laminoplasty on cervical movement and alignment were investigated by radiography and CT scans in a study of 56 patients with multisegmental myelopathy who had undergone a C3 to C7 open-door laminoplasty. Follow up averaged 5.8 years. Satisfactory neurological improvement occurred in 73%. Cervical flexion decreased by 35% and extension by 57%; the decrease of both movements was statistically significant. Decreased vertebral slip, as well as slightly reduced lordosis, was seen after operation. Increase in measured canal size after operation and at follow up was 48% and 40%; 8% of the expanded canal size was lost at the last follow up. Expansive open-door laminoplasty leads to a better neurological prognosis in this group of patients, while maintaining an increase in canal size and preserving spinal stability.

Aged↗
PubMed1995

The cervical spine in the Klippel-Feil syndrome. A report of 57 cases.

We report 57 cases of the Klippel-Feil syndrome. Five had type I congenital cervical fusion, 48 type II and 4 type III. The symptoms and signs varied considerably. Patients with C2-C3 fusion often had symptoms associated with odontoid dysplasia and occipito-cervical instability. Twenty-one had progressive neurological symptoms and 19 were operated on: 3 had occiput-C3 posterior arthrodeses, 2 a single level fusion, 1 a laminectomy and anterior arthrodesis, and 13 had laminoplasties. Degenerative changes at the unfused segment and a narrow bony canal are high risk factors in the development of neurological compromise.

Adolescent↗
PubMed1995

Association of a restriction fragment length polymorphism in the alcohol dehydrogenase 2 gene with Japanese alcoholic liver cirrhosis.

BACKGROUND/AIMS: The association of ADH2 polymorphisms with alcoholic liver cirrhosis has not been clearly demonstrated. METHODS: We investigated the association of two alleles in the ADH2 gene marked by restriction fragment length polymorphisms in patients with alcoholic liver cirrhosis. The ADH2 restriction fragment polymorphisms with Mae III were determined using the polymerase chain reaction on lymphocytes from 76 male Japanese alcoholics (non-cirrhotic patients; 34 cases, cirrhotic patients; 42 cases) and 60 healthy male subjects. RESULTS: The frequency of the ADH2(1)/ADH2(1) genotype was significantly higher in the alcoholics than in the healthy subjects p < 0.001). In the alcoholics, the genotype ADH2(2)/ADH2(2) was significantly more prevalent in the cirrhotic group than in the non-cirrhotic group (p < 0.05). CONCLUSIONS: These results suggest that the Mae III polymorphisms of the ADH2 gene may be associated not only with susceptibility to alcoholic liver cirrhosis, but also with the development of alcoholism in Japanese patients.

Adult↗
PubMed1995

Polymorphisms in alcohol metabolizing enzyme genes and alcoholic cirrhosis in Japanese patients: a multivariate analysis.

Alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and P450IIE1 are the primary enzymes that catalyze the conversion of ethanol to acetaldehyde and then to acetate. Genetic polymorphisms have been reported in ADH2, ADH3, ALDH2, and the 5'-flanking region of P450IIEI. In this study, we used multivariate analysis to determine which genetic polymorphisms in alcohol metabolizing enzymes were independently associated with the development of alcoholic cirrhosis. Thirty-four noncirrhotic alcoholic patients, including 27 with fatty liver and 7 with nonspecific changes, and 46 patients with alcoholic liver cirrhosis were studied. Restriction fragment length polymorphisms (RFLPs) in the ADH2 and P450IIE1 genes were detected by digestion of polymerase chain reaction (PCR)-amplified DNA with MaeIII and RsaI, respectively. In the ALDH2 gene, RFLPs were detected by differences in the MboII site after PCR amplification. By multivariate analysis of four significant factors including total alcohol intake, ADH, ALDH, and P450IIE1 using the multiple logistic regression model, genotype ADH2(2)/ADH2(2) (P = .029) and genotype c1/c1 of P450IIE1 (P = .013) were found to be independently associated with alcoholic cirrhosis. The odds ratios for ADH2(2)/ADH2(2) genotype and the type A genotype of P450IIE1 (c1/c1) were 4.600 and 4.006, respectively. These results suggest that ADH2 and P450IIE1 gene polymorphisms may be independently associated with the development of alcoholic liver cirrhosis in Japan.

Adult↗