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Biomedical subjects

J Mizuno

Publications and source records attributed to J Mizuno.

At least 19 recordsLinked to original sources
PubMed2005

Immunohistochemistry of symptomatic hypertrophy of the posterior longitudinal ligament with special reference to ligamentous ossification.

STUDY DESIGN: Immnunohistochemical staining of the thickened posterior longitudinal ligament of the cervical spine. OBJECTIVES: To clarify the histological characteristics of hypertrophy of the posterior longitudinal ligament (HPLL) of the cervical spine and the relationship between HPLL and ossification of the posterior longitudinal ligament (OPLL). SETTING: Aichi Medical University, Aichi, Japan. METHODS: Eight specimens of HPLL and two of OPLL were obtained during anterior decompressive surgery on the cervical spine from patients with myelopathy. Hematoxylin and eosin staining, alcian blue staining and immunohistochemical staining with antibodies against bone morphogenetic protein (BMP), transforming growth factor (TGF)-beta, proliferating cell nuclear antigen (PCNA), alkaline phosphatase (ALP) and osteopontin (OPN) were carried out on the specimens. RESULTS: HPLL showed hyalinoid degeneration, the proliferation of chondrocytes and fibroblast-like spindle cells, infiltration of vessels and small ossification. In four cases, chondroid tissue was prominent with chondrocytes, which were expressed by ALP and OPN. The cells in HPLL were weakly or moderately stained by BMP, TGF-beta and PCNA. Their expression was similar to that of OPLL. Immunohistochemical staining was negative for all cells in the control cases. CONCLUSIONS: Histological and biochemical evidence supports the hypothesis that HPLL transforms into OPLL. The positive expression of BMP and TGF-beta in HPLL cells of myelopathic patients, and their similarity to OPLL, suggest that these cells have the potential to differentiate into osteogenic cells. Of note, neither BMP nor TGF-beta was demonstrated in the PLL of control subjects. Furthermore, the expression of chondrocytes by ALP and OPN in cartilage-prominent HPLL suggests that the cartilage can be replaced by new bone.

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PubMed2005

Postmortem study of the spinal cord showing snake-eyes appearance due to damage by ossification of the posterior longitudinal ligament and kyphotic deformity.

UNLABELLED: CLINICAL DESIGN: A case report. OBJECTIVES: To elucidate the clinical role of snake-eyes appearance in this case, correlation between radiological, clinical and postmortem study was performed. SETTING: Aichi, Japan. CASE REPORT: A 73-year-old man developed weakness and pain in the upper limbs due to kyphotic deformity secondary to laminectomy for cervical ossification of the posterior longitudinal ligament. Axial magnetic resonance imaging revealed snake-eyes appearance from C4 to C6. He died of acute myocardial infarction 3 months after anterior decompressive surgery. RESULTS: A postmortem examination of the cervical spinal cord showed small cystic six necrotic areas at the junction of the central gray matter and the ventrolateral posterior column, one in the right and one in the left, in association with neuronal loss in the anterior horn. CONCLUSIONS: Bilateral small intramedullary high-signal areas known as 'snake-eyes appearance' located around the central gray matter and the ventrolateral posterior column, are associated with neuronal loss in the compressed anterior horn that played an important role in worsening weakness of the upper limbs.

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PubMed2005

Symptomatic ossification of the anterior longitudinal ligament with stenosis of the cervical spine: a report of seven cases.

Seven men with a mean age of 63.9 years (59 to 67) developed dysphagia because of oesophageal compression with ossification of the anterior longitudinal ligament (OALL) and radiculomyelopathy due to associated stenosis of the cervical spine. The diagnosis of OALL was made by plain lateral radiography and classified into three types; segmental, continuous and mixed. Five patients had associated OALL in the thoracic and lumbar spine without ossification of the ligamentum flavum. All underwent removal of the OALL and six had simultaneous decompression by removal of ossification of the posterior longitudinal ligament or a bony spur. All had improvement of their dysphagia. Because symptomatic OALL may be associated with spinal stenosis, precise neurological examination is critical. A simultaneous microsurgical operation for patients with OALL and spinal stenosis gives good results without serious complications.

Aged↗
PubMed2004

Load independence of temperature-dependent Ca2+ recirculation fraction in canine heart.

Intramyocardial Ca(2+) recirculation fraction (RF) critically determines the economy of excitation-contraction coupling. RF is obtainable from the exponential decay of the postextrasystolic potentiation of left ventricular (LV) contractility. We have shown that RF remains unchanged despite increasing LV volume (LVV) at normothermia, but decreases with increasing temperature at a constant LVV. However, it remains unknown whether the temperature-dependent RF was not due to the simultaneously changed peak LV pressure (LVP) at a constant LVV. We hypothesized that this temperature-dependent RF would be independent of the simultaneous change in LVP. We used nine excised, cross-circulated canine hearts and allowed their LVs to contract isovolumically. During stable regular beats at 500 msec intervals, we inserted an extrasystolic beat at 360 msec interval followed by the postextrasystolic beats (PESs) at 500 msec intervals. We equalized the temperature-dependent peak LVPs of the regular beats at 36 degrees C and 38 degrees C to the peak LVP level of the stable regular beat at 33 degrees C by adjusting LVV. We fitted the same equation: nEmax = a.exp[-(i - 1)/tau(e)] + b.exp[-(i - 1)/tau(s)]cos[pi(i - 1)] + 1, used before to the normalized Emax (maximum elastance) values of PESi (i = 1-6) relative to the regular beat Emax. RF given by exp(-1/tau(e)) decreased by 19% to 38 degrees C from 33 degrees C. The temperature coefficient (Q(10)) of 1/RF was significantly greater than 1.3. The present results indicated a similar temperature dependence of RF and its Q(10) to those we observed previously without equalizing peak LVP. Thus, the temperature-dependent RF is independent of ventricular loading conditions.

Animals↗
PubMed2004

C7 fracture treated with a pedicle screw system under navigation guidance.

A 51-year-old woman with traumatic fracture-subluxation of C6-C7 vertebrae was treated by pedicle screw fixation. Among several methods for surgical treatment of the cervical spine, this technique provides a more rigid anchor to prevent collapsing or instability of the spinal column, particularly at the cervicothoracic junction. However, the risk of injuring the adjacent neurovascular structures cannot be completely eliminated. The characteristics of the cervicothoracic junction, surgical approaches and pedicle screw fixation techniques are emphasised.

Bone Screws↗
PubMed2002

Cervical amyotrophy caused by hypertrophy of the posterior longitudinal ligament.

STUDY DESIGN: A case report. OBJECTIVES: To report a case of cervical amyotrophy caused by hypertrophy of the posterior longitudinal ligament (HPLL). SETTING: Department of Neurological Surgery, Aichi Medical University, Aichi, Japan. METHODS: The patient had severe muscular atrophy in the deltoid and triceps with slight localized hypesthesia in the C5 area and severely unstable gait due to diminished vibration sense in the knees and ankles. Magnetic resonance imaging (MRI) showed expanded cord compression from C4 to C6 with intramedullary high-signal intensity due to HPLL. Transverse image MRI was useful to identify the HPLL. RESULTS: Resection of HPLL was achieved by an anterior approach. Histological findings of the surgical specimens showed thickening of the ligamentous tissue with proliferation of chondrocytes. CONCLUSIONS: HPLL should be included as a causative pathology of cervical spondylotic amyotrophy. Careful neurological examination including sensory examination of the lower limbs should be performed to avoid confusion with motor neuron disease.

Cervical Vertebrae↗
PubMed2001

Outcome analysis of anterior decompressive surgery and fusion for cervical ossification of the posterior longitudinal ligament: report of 107 cases and review of the literature.

OBJECT: This study was designed to determine the surgical technique and surgery-related outcome, fusion rate, and complication of anterior decompression and fusion (with various graft materials) performed in patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. METHODS: Between 1980 and 1998, 107 patients with radiologically proven OPLL underwent surgery via the anterior approach for direct removal of the ossified mass. Graft materials included iliac crest in 45 cases, vertebral body (VB) in 37 cases; and interbody fusion cages in 25 cases. In four patients with three-level VB grafts and one with a two-level VB graft, anterior plates were placed. Surgery-related outcome was excellent or good in 89% and fair in 11%. This clinical improvement correlated well with the severity of preoperative myelopathy. Only one patient with severe myelopathy due to extensive mixed-type OPLL developed a segmental weakness of the bilateral upper extremities. The overall fusion rate was 97%. Three patients with obvious spinal instability due to pseudarthrosis required reoperation. Of the graft materials used in this series, VB grafts were the most fragile. CONCLUSIONS: The anterior approach is an effective route for decompressing the cervical cord with OPLL. Slight asymptomatic kyphotic deformity may be encountered. Of the graft materials used in our series, VB graft was considered most fragile, and thus least optimal.

Adult↗
PubMed2001

Primary amyloidoma of the thoracic spine presenting with acute paraplegia.

BACKGROUND: Primary solitary amyloidoma of the spine is a rare disease characterized by localized deposition of amyloid. To the best of our knowledge, there have been only 14 cases previously reported in the literature. Patients with focal spinal amyloidoma usually have relatively long symptomatic periods preoperatively, ranging from 3 weeks to 6 years (mean: 12 months). Only two reported patients had acute paraplegia. We add a third case of a thoracic spine amyloidoma presenting with acute paraplegia. CASE DESCRIPTION: A 65-year-old man presented with a three-day history of progressive paraplegia and urinary retention. He was found to have severe cord compression at T2 on magnetic resonance imaging. He underwent emergent decompressive laminectomy with instrumentation for spinal stabilization. Histopathology revealed abundant amyloid deposits. A systemic work-up was negative for amyloidosis. The patient showed marked neurological improvement with residual mild spastic gait after 1 year. CONCLUSIONS: Primary spinal amyloidoma with acute paraplegia is rare. One-stage surgery combining prompt decompression and stabilization of the spinal column is mandatory in cases of spinal amyloidoma with acute myelopathy, because primary solitary amyloidoma carries a good prognosis.

Acute Disease↗
PubMed2001

Combined anterior and posterior instrumentation in severe fracture-dislocation of the lower cervical spine with help of navigation: a case report.

The authors report a case of severe fracture-dislocation of C6-C7 with dural and spinal cord damage causing quadriplegia. The patient was treated surgically with circumferential stabilisation. Intense spinal instrumentation with pedicle screw fixation in addition to anterior decompression and plate fixation was essential for restoring the original vertebral column. This technique of internal fixation provided a more rigid anchor, however the risk to the neurovascular structures could not be completely eliminated. Therefore, the combined anterior and posterior stabilisation assisted with a navigation system was a safer and reasonable surgical treatment for this patient with severe cervical injuries.

Adult↗
PubMed2001

Analysis of hypertrophy of the posterior longitudinal ligament of the cervical spine, on the basis of clinical and experimental studies.

OBJECTIVE: The goal of this study was to elucidate the pathophysiological features and treatment of hypertrophy of the posterior longitudinal ligament (HPLL) of the cervical spine. HPLL is defined as a pathological thickening of the posterior longitudinal ligament (PLL), causing spinal cord compression. Incomplete decompression via removal of only coexisting herniated intervertebral discs or spondylotic spurs might be performed, resulting in unsatisfactory surgical outcomes, when the PLL becomes abnormally thickened and contributes to myelopathy. METHODS: Patients with HPLL who underwent cervical decompression surgery were selected. Medical records and radiographs were retrospectively reviewed, to obtain data on the pre- and postoperative clinical conditions of the patients. Autopsy cases with HPLL proven by low-energy x-ray examinations were chosen for assessment of the pathological characteristics. RESULTS: Seventeen men and three women with HPLL underwent treatment via an anterior approach, with direct removal of HPLL. Nineteen patients developed myelopathy, whereas one patient developed radiculopathy. Radiologically, all HPLL cases exhibited coexisting herniated intervertebral discs and 10 exhibited small segmental ossifications of the PLL. Magnetic resonance imaging or computed tomographic myelography revealed extensive cord compression across the vertebral endplate level. The average preoperative Benzel modified Japanese Orthopaedic Association score was 10.8, and the average postoperative score was 13.2. Histological examinations revealed thickening of the PLL with proliferation of chondrocytes, together with various degenerative changes. CONCLUSION: Patients with HPLL can benefit from an anterior approach with direct removal of the HPLL and associated herniated intervertebral discs or ossification of the PLL. Cervical polytomography, computed tomography, and magnetic resonance imaging are useful in establishing a diagnosis of HPLL.

Adult↗
PubMed2001

Frank-Starling mechanism retains recirculation fraction of myocardial Ca(2+) in the beating heart.

Myocardial Ca(2+) handling in excitation-contraction coupling is the second primary determinant of energy or O(2) demand in a working heart. The intracellular and extracellular routes remove myocardial Ca(2+) that was released into the sarcoplasma with different Ca(2+): ATP stoichiometries. The intracellular route is twice as economical as the extracellular route. Therefore the fraction of total Ca(2+) removed via the sarcoplasmic reticulum, i.e., the recirculation fraction of intracellular Ca(2+) (RF), determines the economy of myocardial Ca(2+) handling. RF has conventionally been estimated as the exponential decay rate of postextrasystolic potentiation (PESP). However, we have found that PESP usually decays in alternans, but not exponentially in the canine left ventricle beating above 100 beats/min. We have succeeded in estimating RF from the exponential decay component of an alternans PESP. We previously found that the Frank-Starling mechanism or varied ventricular preload did not affect the economy of myocardial Ca(2+) handling. Then, to account for this important finding, we hypothesized that the Frank-Starling mechanism would not affect RF at a constant heart rate. We tested this hypothesis and found its supportive evidence in 11 canine left ventricles. We conclude that RF at a constant heart rate would remain constant, independent of the Frank-Starling mechanism.

Action Potentials↗
PubMed2001

Two-staged operation for thoracolumbar osteomyelitis following methicillin-resistant staphylococcus aureus infection of a craniectomy wound--case report.

A previously healthy 53-year-old woman developed pyogenic vertebral osteomyelitis (PVO) manifesting as progressive lumbago following wound infection of a decompressive craniectomy performed for brain contusion caused by a traffic accident. Magnetic resonance imaging disclosed vertebral osteomyelitis at T-12 and L-1 with paravertebral abscess. Anterior debridement and fusion using autografts were performed at the first operation. Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from the abscess specimen. Antibiotic therapy resolved the infection. Pedicle screw fixation was performed at the second operation. The patient became free from back pain and no recurrence of infection was seen. The diagnosis of PVO is frequently observed or delayed because of the nonspecific symptomatic presentation in the early stage. Coexistent infection or trauma makes early diagnosis more difficult. Indications and timing of instrumentation for the spinal column infected with MRSA is difficult. Two-staged operation with anterior debridement and posterior instrumentation after eradication of the infection is a safe and effective procedure for MRSA vertebral osteomyelitis.

Craniotomy↗
PubMed2001

[Convulsion following the combination of single preoperative oral administration of enoxacine and single postoperative intravenous administration of flurbiprofen axetil].

We experienced a case of convulsion following the combination of single oral administration of enoxacine before an emergency operation and single postoperative intravenous administration of flurbiprofen axetil. The patient was an 87-year-old female referred to our hospital for severe abdominal pain. She was diagnosed as having the strangulation ileus, then underwent the emergent operation of partial resection of the necrotic small intestine under general anesthesia. Unfortunately we did not know that she had temporarily received oral enoxacine 200 mg, a new quinolone, administered by the previous doctor on the day before the operation. After the operation, flurbiprofen axetil 50 mg, a nonsteroidal anti-inflammatory drug, was given intravenously in thirty seconds due to postoperative pain. One minute after administration of the drug, she immediately developed a convulsive fit, severe disturbance of consciousness and apnea. We then administered at once, a single dose of diazepam intravenously for convulsion treatment, kept her airway open and controlled her ventilation. Convulsion disappeared in a minute and her condition improved gradually. We suspect that convulsive seizure may have been induced by the drug interaction between single oral dose of enoxacine before the operation and single intravenous dose of flurbiprofen axetil after the operation. We also suspect that the serum concentration of enoxacine was kept high because of metabolic disturbance and renal dysfunction resulting from her old age and dehydration. This case suggests that medication before the emergency operation must be considered in anesthetic management because of the possible side effect such as convulsion induced by the drug interaction between neuquinolones and anti-inflammatory drugs.

Administration, Oral↗
PubMed2001

[Treatment with stellate ganglion block, continuous epidural block and ulnar nerve block of a patient with postherpetic neuralgia who developed complex regional pain syndrome (CRPS)].

We present a case of a 46-year-old female patient with systemic lupus erythematosus who developed herpes zoster of the right eighth cervical nerve. Her whole right forearm, hand and the first through fifth fingers were coated with some gel and protected against pain. She had been suffering from continuous and spasmodic burning pain, hyperalgesia, allodynia, drop in skin temperature, sudmotor disturbance, edema, constructure of the joints, muscle atrophy and bone atrophy of her right upper extremity probably due to postherpetic neuralgia (PHN) associated with complex regional pain syndrome (CRPS). She received right stellate ganglion block (SGB), continuous cervical epidural block and right ulnar nerve block. Reduction of pain and edema as well as improvement in mobility of each joint of her right upper extremity was observed. We suspect that SGB, continuous cervical epidural block and ulnar nerve block are effective and useful alternative treatments in a patient with PHN associated with CRPS of the eighth cervical nerve.

Analgesia, Epidural↗
PubMed2001

[Usefulness of epidural infusion of ketamine for relief of localized superficial pain].

Three patients with localized superficial pain had their pain alleviated by single epidural infusion with low dose ketamine. The patients are as follows: a 62-year-old female with herpetic neuralgia on her right sixth thoracic nerve area; a 52-year-old male whose left shoulder, anterior chest and abdomen had been burned by acetylene gas; and a 49-year-old male whose bilateral hands suffering from frostbite by propane gas. Epidural tube insertion to administer a single dose of 10 mg ketamine with lidocaine or bupibacaine was performed in all the three patients. They were administered single epidural infusion of 10 mg ketamine with lidocaine or bupibacaine everyday and they continued to receive epidural block with lidocaine or bupivacaine including buprenorphine or morphine. Therefore, we suspect that single epidural infusion of ketamine, an antagonist for N-methyl-D-aspartic acid receptor, could be an effective and useful alternative treatment in patients with various refractory localized superficial pain of either acute or chronic nature.

Analgesia, Epidural↗
PubMed2001

[Stump pain relieved by continuous intravenous ketamine infusion therapy].

We experienced a case of stump pain relieved by continuous intravenous ketamine infusion therapy. A 59-year-old male had his left first through fourth toes amputated because a giant iron plate at work fell on his left foot fifteen years ago. Thereafter he had refractory spontaneous burning pain and night pain on his stump. On examination, we found his left foot skin hard, lustrous, and with sweating disturbance, allodynia and hyperpathia. As intravenous administrations of ketamine 10 mg and thiamylal 50 mg were positive as a drug challenge test, we performed intravenous ketamine infusion at 1 mg.kg-1.hr-1 for 1 hour and a half. After this treatment, his visual analogue scale (VAS) improved dramatically to 0 mm, and night pain, allodynia and hyperpathia disappeared for three days. Thereafter stump pain was relieved to the level of VAS 20 mm. Therefore we diagnosed his stump pain as central pain of neuropathic origin. We suspect that continuous intravenous infusion of ketamine, a noncompetitive blocker of N-methyl-D-aspartic acid receptor, might be an effective and useful alternative treatment in a patient with refractory stump pain.

Excitatory Amino Acid Antagonists↗
PubMed2001

[Usefulness of epidural administration of ketamine for relief of postherpetic neuralgia].

Four patients with postherpetic neuralgia had their pain alleviated by epidural administration of ketamine. No oral non-steroidal anti-inflammatory drugs and anti-depressant drugs were effective in all cases. Lidocaine or bupivacaine was administered epidurally to all four patients. When these patients stated that they did not feel pain reduced, they received epidural infusion of ketamine at doses from 5 mg to 20 mg with lidocaine or bupivacaine and their postherpetic neuralgia was controlled. Therefore with these cases, we suspect that epidural administration of ketamine, an antagonist for N-methyl-D-aspartic acid receptor, could be an effective and useful alternative treatment in a patient with refractory postherpetic neuralgia.

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