Search PubMed⌕ Search

Biomedical subjects

Akira Matsumura

Publications and source records attributed to Akira Matsumura.

At least 19 recordsLinked to original sources
PubMed2006

Spontaneous regression of osteochondromas.

Spontaneous regression of an osteochondroma is an infrequent event. In this report, two cases with spontaneous regression of osteochondromas are presented. The first case was a solitary osteochondroma of the pedunculated type involving the right proximal humerus in a 7-year-old boy. This lesion resolved over 15 months of observation. The second case was a 3-year-old girl with multiple osteochondromatosis, in whom sessile osteochondromas of the right tibia and left fibula regressed over 33 months. The mechanism of this phenomenon is discussed with a review of previous reports. Regarding treatment, careful observation may be acceptable for typical osteochondromas, especially in young children.

Bone Neoplasms↗
PubMed2006

Comparative study of radiographic disc height changes using two different interbody devices for transforaminal lumbar interbody fusion: open box vs. fenestrated tube interbody cage.

STUDY DESIGN: Retrospective comparative study of the postoperative subsidence of two interbody devices following posterior or transforaminal lumbar interbody fusion (PLIF/TLIF) for degenerative spondylolisthesis of the lumbar spine. OBJECTIVE: To assess certain radiograph characteristics of PLIF/TLIF using two interbody fusion devices at L4-L5. SUMMARY OF BACKGROUND DATA: PLIF can achieve spinal stabilization with vertebral body support and direct neural decompression. Although various interbody devices have been used in PLIF procedures, no radiographic studies have compared the load-bearing capabilities of open box and fenestrated tube interbody cages. METHODS: Seventy-five patients who underwent one-level PLIF in the L4-L5 [corrected] segment for degenerative spondylolisthesis were retrospectively reviewed with a minimum 2-year follow-up. Fenestrated tube (Group FT: n = 30 [corrected]) or open box (Group OB: n = 45 [corrected]) cages were used for the PLIF procedure. The following radiographic parameters were evaluated to compare the load-bearing capabilities: disc space height (DH); percent increase and decrease of disc height (% IDH and % DDH, respectively); and percent coverage of the cage on the endplate (% CC). RESULTS: There were no significant differences in the baseline data, including age, segmental instability and osteoporotic status, between the two groups. Anterior %IDH and % CC were significantly higher in Group OB than in Group FT (% IDH: 69.4% vs. 57.3%; % OC: 24.5% vs. 12.9%), and anterior and posterior % DDH were significantly higher in Group FT than in Group OB (anterior: -2.9% vs. -.1%; posterior: -6.6% vs. -.3%). Although the restored DH gradually reduced over time in both groups, significant reduction to the preoperative level only occurred in Group FT. CONCLUSIONS: The load-bearing capabilities of the open box cage are superior to those of the fenestrated tube cage. Since there were no significant differences between the baseline status of the two groups, the larger cross-sectional area and stable framework design of the open box cage appears to bring about a greater load-bearing capability. Therefore, the open box cage seems to be biomechanically more advantageous as an interbody device for PLIF than the fenestrated tube cage.

Aged↗
PubMed2006

Olfactory ensheathing cell tumor: a case report.

A 31-year-old Japanese woman was referred to our hospital after experiencing a convulsion. Upon radiological examination, a heterogeneously enhanced tumor was found on the anterior skull base. The tumor was surgically removed. On light microscopy, the tumor cells appeared spindle-shaped, forming an interwoven pattern. The nuclei were arranged partially parallel mimicking a palisading pattern. At first, the tumor was thought to be schwannoma. However, it was positive for S-100 and negative for both epithelial membrane antigen (EMA) and Leu7. The final diagnosis was olfactory ensheathing cell (OEC) tumor. OECs are similar to Schwann cells in microscopic appearance and upon immunohistochemical staining. However, the OECs are negative for CD57 (Leu7), while the Schwann cells are positive for it. Our patient's tumor had immunological characteristics identical to those of OEC. In the English and Japanese literature, 21 cases of solitary schwannoma on the anterior skull base have been reported. Although several theories have been suggested, the pathogenesis of subfrontal schwannoma has not been clarified. Also, OECs have never been considered as their origin. However, as in our case, OECs, rather than Schwann cells, are suspected as the origin in some of the cases.

Adult↗
PubMed2006

Excision of juvenile pilocytic astrocytoma of the midbrain after radiotherapy.

A 13-year-old girl presented with consciousness disturbance, right hemiparesis, and impairment of hearing, swallowing, and ocular movements. A magnetic resonance image demonstrated marked hydrocephalus due to a large cystic tumor (40 x 40 x 30 mm) in the midbrain. Emergency ventricular drainage and stereotactic cyst puncture dramatically improved her condition. Since her family did not agree to surgery on the brain stem, radiotherapy was performed after ventriculoperitoneal shunting. Conventional radiotherapy of 50.4 Gy was temporarily effective, and the growth of the tumor was stabilized until approximately 8 months later when regrowth was noticed. At this stage, with the consent of her family, the tumor was removed via an infratentorial supracerebellar approach. The pathological diagnosis was juvenile pilocytic astrocytoma. The postoperative course was uneventful. No recurrence has been observed during the follow-up period of more than 6 years. This case study shows that initial excision may be appropriate for some low-grade focal lesions in the midbrain when the histological diagnosis and consent have been obtained.

Adolescent↗
PubMed2006

Predictors of angiographic changes in neck remnants of ruptured cerebral aneurysms treated with Guglielmi detachable coils.

The angiographic changes in neck remnants of ruptured cerebral aneurysms treated with Guglielmi detachable coils (GDCs) were evaluated in the acute stage to analyze the important radiological and clinical factors. The clinical and radiological data of 37 patients with a residual neck of a ruptured cerebral aneurysm treated with GDC were reviewed. The angiographic changes on follow-up angiography were classified into three groups: recanalization of the neck remnant, progressive thrombosis, and unchanged. The effects of the clinical and angiographic findings, such as patient age, follow-up period, type of aneurysm (terminal type or side wall type), dome diameter, neck size, dome/neck ratio, obliteration rate, and volume embolization ratio were investigated. Recanalization of the neck remnant was observed in 18 of 37 cases, progressive thrombosis in nine, and unchanged in 10. The type of aneurysm, dome diameter, neck size, and volume embolization ratio were correlated with changes in the neck remnant. The aneurysm dome diameter and type of aneurysm were independent predictive factors for the recanalization of neck remnants on follow-up angiography. Dome diameter of less than 4.5 mm and volume embolization ratio of more than 31% in side wall aneurysms were likely to lead to progressive thrombosis.

Adult↗
PubMed2006

Dynamic computed tomography myelography for the investigation of cervical degenerative disease.

Dynamic computed tomography (CT) myelography was conducted in 15 patients with cervical degenerative disease to assess the lesions responsible for their symptoms. CT myelography was performed using a multi-detector row helical CT system in dynamic positions (flexion or extension or both) in addition to the neutral position. Fine sagittal reconstructed images could be obtained in addition to axial images. This method provided static information including cervical vertebral body deformities, and good contrast images of the spinal cord, nerve roots, and cerebrospinal fluid space. In addition, laterality of the offending lesion and changes exaggerated by cervical motion were clearly shown in both axial and sagittal images. Ten of 15 patients demonstrated dynamic changes including dynamic canal stenosis or spinal cord impingement. The operative strategies were changed based on dynamic CT myelography findings in three of the 15 patients. Dynamic CT myelography can provide the axial and sagittal images required for flexion-extension studies, and in combination with conventional imaging modalities, provides valuable information for determining treatment strategies and objectives.

Adult↗
PubMed2006

Lumbosacral subdural hematoma. Case report.

An 18-year-old man presented with a rare spinal subdural hematoma (SSH) manifesting as headache, which developed following diving into the sea the day before. Computed tomography of the head revealed no abnormality. His headache persisted followed by neck stiffness and mild lumbago. He came to see us 6 days after the first visit. He underwent lumbar puncture to eliminate the possibility of meningitis. The cerebrospinal fluid showed xanthochromia. Cerebral angiography showed no abnormality. Magnetic resonance imaging of the spine revealed lumbosacral subdural hematoma. The hematoma and his symptoms regressed spontaneously during several weeks of conservative treatment. A sharp increase in intraabdominal and/or intrathoracic pressures following diving may have caused the bleeding. Headache may be an initial symptom associated with subarachnoid hemorrhage concomitant with SSH. Delayed progression of lumbosacral SSH must be considered if the patient complains of lumbago following minor trauma.

Adolescent↗
PubMed2006

Perfusion-weighted magnetic resonance imaging of the spinal cord in cervical spondylotic myelopathy.

Principles of echo shifting with a train of observations was used to perform magnetic susceptibility-weighted magnetic resonance imaging with bolus-tracking in 14 patients with spondylotic myelopathy to assess changes in perfusion parameters of the spinal cord before and after decompression surgery for cervical spondylotic myelopathy. The mean transit time (MTT), bolus arrival time (T0), and time to peak (TTP) were obtained from regions of interest (ROIs) and assessed as the ratio between the spinal cord and the pons (MTT index = MTT(ROI)/MTT(pons), T0 index = T0(ROI)/T0(pons), TTP index = TTP(ROI)/TTP(pons)). The patients were divided into two groups according to percentage improvement on the Neurosurgical Cervical Spine Scale. The MTT index in patients with good recovery (> or =50%) was significantly reduced. The T0 index and TTP index showed no significant change in both groups. Reduction of MTT index may indicate improved perfusion of the spinal cord following surgery for cervical spondylotic myelopathy.

Aged↗
PubMed2006

Unilateral transforaminal lumbar interbody fusion and bilateral anterior-column fixation with two Brantigan I/F cages per level: clinical outcomes during a minimum 2-year follow-up period.

OBJECT: There are no published reports of unilateral transforaminal lumbar interbody fusion (TLIF) in which two Brantigan I/F cages were placed per level through a single portal to achieve bilateral anterior-column support. The authors describe such a surgical technique and evaluate the clinical outcomes of this procedure. METHODS: Data obtained in 86 (93.5%) of the first 92 consecutive patients who underwent the procedure were retrospectively reviewed; the minimum follow-up duration was 2 years. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scoring system. Disc height, disc angle, cage positioning in the axial plane, and fusion status were radiographically evaluated. The mean follow-up period was 33.8 months. The mean improvement in the JOA score was 77.2%. Fusion was successful in 93% of the cases. According to the Farfan method, the mean anterior and posterior disc heights increased from 20.2 and 16.9% preoperatively to 35.9 and 22.7% at follow up, respectively (p < 0.01). The mean disc angle increased from 4.8degrees preoperatively to 7.5degrees at last follow-up examination (p < 0.01). Two cages were correctly placed to achieve bilateral anterior-column support in greater than 85% of the cases. The following complications occurred: hardware migration in two patients and deep infection cured by intravenous antibiotic therapy in one patient. CONCLUSIONS: Unilateral TLIF involving the placement of two Brantigan cages per level led to good clinical results. Two Brantigan cages were adequately placed via a single portal, and reliable bilateral anterior-column support was achieved. Although the less invasive unilateral approach was used, the outcomes were as good as those in many reported series of posterior lumbar interbody fusion in which the Brantigan cages were placed via the bilateral approach.

Adult↗
PubMed2005

ANCA-associated vasculitis (AAV) causing bilateral cerebral infarction and subsequent intracerebral hemorrhage without renal and respiratory dysfunction.

A 56-year-old man complained of headache and the analgesia of the four extremities. Laboratory data presented signs of inflammation, but no other abnormality such as renal or respiratory dysfunction. Two months after the appearance of the primary symptoms, he developed cerebral infarction of the bilateral corona radiata. The patient did not have any of the risk factors for cerebrovascular disease. He was diagnosed with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) because the systemic examinations revealed only that he tested positive for anti-neutrophil cytoplasmic autoantibody (ANCA). Moreover, the biopsy of the sural nerve displayed microscopic polyangitis (MPA). Despite undergoing steroid pulse therapy, the patient died from the fatal cerebral hemorrhage. The clinical course of AAV is rapid progressive. In cases of atypical cerebrovascular disease, the possibility of ANCA should be investigated.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2005

Dendritic cell maturation by CD11c- T cells and Valpha24+ natural killer T-cell activation by alpha-galactosylceramide.

Human invariant Valpha24+ natural killer T (NKT) cells display potent antitumor activity upon stimulation. Activation of endogenous Valpha24+ NKT cells would be one strategy for the treatment of cancer patients. For example, dendritic cells (DCs) loaded with a glycolipid NKT cell ligand, alpha-galactosylceramide (alphaGalCer, KRN7000), are a possible tool for the activation and expansion of functional Valpha24+ NKT cells in vivo. In this report, we demonstrate that the levels of expansion and the ability to produce IFN-gamma of Valpha24+ NKT cells induced by alphaGalCer-loaded whole PBMCs cultured with IL-2 and GM-CSF (IL-2/GM-CSF-cultured PBMCs) were superior to those of cells induced by monocyte-derived CD11c+ DCs (moDCs) developed with IL-4 and GM-CSF. Interestingly, CD11c+ cells in the IL-2/GM-CSF-cultured PBMCs showed a mature phenotype without further stimulation and exerted potent stimulatory activity on Valpha24+ NKT cells to enable them to produce IFN-gamma preferentially at an extent equivalent to mature moDCs induced by stimulation with LPS or a cytokine cocktail. Cocultivation with CD11c- cells in the IL-2/GM-CSF-cultured PBMCs induced maturation of moDCs. In particular, CD11c-CD3+ T cells appeared to play important roles in DC maturation. In addition, TNF-alpha was preferentially produced by CD11c-CD3+ T cells in IL-2/GM-CSF-cultured PBMCs and was involved in the maturation of moDCs. Thus, the maturation of DCs induced by CD11c- T cells through TNF-alpha production appears to result in the efficient expansion and activation of Valpha24+ NKT cells to produce IFN-gamma preferentially.

Antigens, CD↗
PubMed2005

Selective synthesis of allylated oxime ethers and nitrones based on palladium-catalyzed allylic substitution of oximes.

[reaction: see text] The viability of oximes as nucleophiles in transition-metal-catalyzed allylic substitution was examined. The oxygen atom of oxime acted as a reactive nucleophile in the reaction of a pi-allyl palladium complex. In the presence of Pd(PPh3)4, the allylic substitution of oximes with allylic carbonate afforded the linear O-allylated oxime ethers selectively without a base. In contrast, the palladium-catalyzed reaction with allylic acetate proceeded smoothly in the presence of K2CO3 or Et2Zn as a base. Selective formation of nitrones was achieved by using palladium(II) catalyst. In the presence of Pd(cod)Cl2, the allylic substitution of oximes with allylic acetate afforded the N-allylated nitrones under solvent-free conditions, as a result of the reaction with the nitrogen atom of oximes.

Journal Article↗
PubMed2005

MicroPET detection of enhanced 18F-FDG utilization by PKA inhibitor in awake rat brain.

To obtain PET imaging of glucose metabolism in the brains of conscious rats, a method of rat head fixation was developed. PET measurement with microPET was performed for 60 min after 18F-FDG injection. Significant enhancement of glucose utilization in the right striatum was observed with infusion of Rp-adenosine-3,5-cyclic phosphorothioate triethylamine (Rp-cAMPS). FDG uptake increments were also seen in the ipsilateral frontal cortex and thalamus. As initial FDG uptake in the brain was not significantly altered by Rp-cAMPS, increased glucose metabolism might be due to an increase in the phosphorylation rate by hexokinase rather than the delivery process from plasma to the brain. In contrast to awake rats, the effect of Rp-cAMPS was abolished by anesthesia using chloral hydrate, indicating that neuronal activity has an important role in short term regulation of hexokinase activity through the cAMP/PKA system in the brain. These results strongly demonstrated the value of measuring glucose utilization in the brains of conscious rats.

Anesthetics↗
PubMed2005

Synthesis and in vivo biodistribution of BPA-Gd-DTPA complex as a potential MRI contrast carrier for neutron capture therapy.

p-boronophenylalanine (BPA) conjugated Gd-DTPA complex (3) was synthesized from the active methyne compound 6, the allylic carbonate 7, and BPA by the palladium-catalyzed allylation reaction followed by the DCC coupling reaction. The in vivo biodistribution of complex 3 was evaluated by prompt gamma-ray analysis and alpha-autoradiography using the tumor-bearing rats. High accumulation of gadolinium was observed in the kidney and the %ID values were 0.17 and 0.088 at 20 and 60 min after injection of 3, respectively. The accumulation was also observed in the tumor and the %ID values were 0.010 and 0.0025 at 20 and 60 min after injection, respectively. The visualization experiment of boron distribution in the tumor-bearing rat by alpha-autoradiography indicates that boron was accumulated in the tumor and the intestines at 20 min after injection.

Animals↗
PubMed2005

Non-invasive quantification of lactate by proton MR spectroscopy and its clinical applications.

Lactate is an important metabolite in clinical cases indicating the status of metabolic impairment. We applied a clinically relevant simple method for lactate quantification using magnetic resonance spectroscopy (MRS). We used two long in-phase echo time (TE=272,544 ms) to calculate T2 relaxation time and the absolute concentration of lactate. This method was optimized using phantom study and applied to clinical cases. This technique does not require complicated processing and could be applied in daily clinical practice. Moreover, this technique enables lactate quantification in cases (e.g. tumor) where lipid peak is overlapped with the lactate peak at short echo times.

Adult↗