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Satoru Shimizu

Publications and source records attributed to Satoru Shimizu.

At least 19 recordsLinked to original sources
PubMed2006

Age dependence of fusion of primary occipital sutures: a radiographic study.

PURPOSE: When linear lucency is present in the occipital bone on radiographs throughout childhood, differential diagnosis becomes important because some primary sutures are similar to fractures. The authors here chronicled the normal development of ossification centers, sutures, and synchondroses in the chondrocranium by radiographic examination. METHODS: One hundred and twenty-seven children, aged from newborns to 6 years and without any skull base deformities, were referred to for radiographs of Towne's projection. RESULTS: In the occipital bone at birth, three primary sutures could be identified. At the age of 0-3 years, occipital and innominate sutures started to fuse, this being complete by 4 years, whereas mendosal sutures persisted until 6 years of age, after which no primary sutures could be seen. CONCLUSION: The complex process of skull base development features a step-wise process sutural closure for which radiographic standards allow differential diagnosis from fractures with judgment of the timing.

Aging↗
PubMed2006

Usefulness of transcervical approach for surgical treatment of hypoglossal schwannoma with paraspinal extension: case report.

BACKGROUND: Usefulness of transcervical approach to hypoglossal schwannoma with paraspinal extension is described herein. CASE DESCRIPTION: A 54-year-old woman presented with gradually worsening left hypoglossal nerve palsy. The findings were of a tumor lying in the left hypoglossal canal and paraspinal region and were consistent with hypoglossal schwannoma. Subtotal intracapsular removal of the tumor was performed via transcervical approach. The symptoms improved, and no additional symptoms were noted. CONCLUSION: The transcervical approach and intracapsular removal of the tumor under electrophysiological monitoring provided for successful minimally invasive surgery in this case of hypoglossal schwannoma.

Cervical Vertebrae↗
PubMed2006

Crystal structure of d(gcGXGAgc) with X=G: a mutation at X is possible to occur in a base-intercalated duplex for multiplex formation.

DNA fragments with the sequences d(gcGX[Y]n Agc) (n=1, X=A, and Y=A, T, or G)form base-intercalated duplexes, which is a basic unit for formation of multiplexes such as octaplex and hexaplex. To examine the stability of multiplexes, a DNA with X=Y=G and n=1 was crystallized under conditions different from those of the previously determined sequences, and its crystal structure has been determined. The two strands are coupled in an anti-parallel fashion to form a base-intercalated duplex, in which the first and second residues form Watson-Crick type G:C pairs and the third and sixth residues form a sheared G:A pairs at both ends of the duplex. The G4 and G5 bases are stacked alternatively on those of the counter strand to form a long G column of G3-G4-G5*-G5-G4*-G3*, the central four Gs being protruded. In addition, the three duplexes are associated to form a hexaplex around a mixture of calcium and sodium cations on the crystallographic threefold axis. These structural features are similar to those of the previous crystals, though slightly different in detail. The present study indicates that mutation at the 4th position is possible to occur in a base-intercalated duplex for multiplex formations, suggesting that DNA fragments with any sequence sandwiched between the two triplets gcG and Agc can form a multiplex.

Base Pairing↗
PubMed2006

Multiplex formation of repetitive sequences d([G]nA)m through non-WC pairings: crystal structure of d(gcGAGGGAgc).

The crystal structure of a DNA fragment with the sequence d(gcGA[G](3)Agc), a shortened and mutated derivative of the VNTR sequence d(ccGA[G](4)Agg), has been determined by X-ray analyses at 1.8 A resolution to investigate structures and mechanisms of a non-coding DNA. This sequence forms an antiparallel duplex with two WC pairings at the both ends and six consecutive non-WC pairings in the major part. Based on this structure, d(GA[G](n)A) (n=3-6) and d([G](n)A)(m) (n>1 and m>1) were designed. It is expected that all bases form non-WC pairs when the DNA fragments adapt antiparallel duplex. Electrophoresis experiments showed that these DNA fragments form not only duplexes, but also multiplexes such as quadruplexes, octaplexes, and so on.

Base Pairing↗
PubMed2006

Anatomic dissection and classic three-dimensional documentation: a unit of education for neurosurgical anatomy revisited.

OBJECTIVE AND IMPORTANCE: Despite development of computer-assisted neurosurgical navigation, learning by dissecting anatomic specimens is still important. CLINICAL PRESENTATION: We describe the processes from preparation of specimens for cranial dissection to documentation of three-dimensional (3-D) stereoscopic pictures, particularly focusing on the latter, which has been initiated in the Microneuroanatomy Laboratory, Department of Neurological Surgery, University of Florida. INTERVENTION: Preparation consists of irrigation of the major vessels and injection of colored silicone. The 3-D documentation, obtaining two pictures corresponding to each eye's view, is obtained by the shoot-shift-shoot method using a single camera mounted on a slide bar. The key of this method is correct shifting of the camera without alignment error to get exact 3-D effects. Observation of 3-D image can be made with free viewing, a 3-D viewer, or projection. Tips concerning all of the processes involved are described. CONCLUSION: The presented method of dissection and obtaining 3-D images is beneficial for accomplishing studies of anatomy and for providing teaching method.

Dissection↗
PubMed2006

Risk of damage to the endolymphatic sac and duct during removal of the posterior meatal wall: an anatomic study.

OBJECTIVE: With removal of the posterior meatal wall for intrameatal acoustic neurinoma, preservation of the structures adjacent to the internal acoustic meatus is important. The authors performed an anatomic study to clarify the risk of damage to the endolymphatic sac and endolymphatic duct during this maneuver. METHODS: Twenty-seven sides of adult temporal bone were examined. Distances measured were between the posterior meatal lip and the upper limit of the endolymphatic ledge, at the upper extent of the endolymphatic sac, and between a reference line extending from the inferior margin of the internal acoustic meatus posteriorly (parallel to the petrous ridge), simulating the inferior margin of the drilling, and the upper limit of the endolymphatic ledge. Whether the latter was located on or above the line was also recorded. After posterior meatal wall drilling, the distance between the posterior meatal lip and the vestibular aqueduct surrounding the endolymphatic duct and the depth of the structure from the surface were assessed. RESULTS: The shortest distances between the posterior meatal lip and the endolymphatic ledge and between the posterior meatal lip and the vestibular aqueduct were 6.80 mm and 4.68 mm, respectively. The upper limit of the endolymphatic ledge was present on or above the reference line in approximately half of the specimens. CONCLUSION: During surgical maneuvers to remove the posterior meatal wall, the occasional close proximity of the endolymphatic sac and endolymphatic duct to the internal acoustic meatus should be kept in mind. Preoperative radiological evaluation of anatomic relationships is mandatory when preservation of hearing is the aim.

Endolymphatic Duct↗
PubMed2006

Alteration of the pressure setting of a Codman-Hakim programmable valve by a television.

A 7-year-old girl presented in semicomatose condition. She had received a ventriculoperitoneal shunt using a Codman-Hakim programmable valve. Head computed tomography demonstrated hydrocephalus and head radiography showed that the pressure setting of the shunt valve had changed to 60 mmH(2)O from 40 mmH(2)O. The pressure setting was returned to 40 mmH(2)O, and she was discharged because her clinical symptoms and hydrocephalus improved. One month later, she lost consciousness again and was transported to our hospital. Hydrocephalus and shunt valve pressure of 50 mmH(2)O were noted, and the pressure setting was returned to 40 mmH(2)O again. She was discharged without complications. We suspected that the valve pressure was caused by close contact with a television, because the patient tended to touch a television with her head during play. The valve pressure did not change after the television was placed on a high stand out of reach. We should recognize that there are many sources of weak magnetic fields that may influence a programmable valve in everyday life.

Child↗
PubMed2006

Neuroendoscopic appearance of an intraventricular cavernous angioma blocking the foramen of monro - case report.

A 47-year-old woman presented with unilateral ventricular enlargement detected by magnetic resonance imaging during a medical checkup. Neuroendoscopic exploration identified a multilocular lesion in which dark red fluid formed a niveau near the right side of the foramen of Monro. The diagnosis was intraventricular cavernous angioma. Restricted flow of cerebrospinal fluid at the foramen of Monro was observed. Xanthochromia, which seemed to be due to previous bleeding, was observed at the fornix. When the neuroendoscope touched the angioma, the wall collapsed and bled. Endoscopic removal of the angioma was abandoned, and craniotomy and resection of the angioma were performed. No new neurological anomalies were observed after surgery. Preoperative diagnosis of intraventricular cavernous angioma is difficult based on neuroimaging. Neuroendoscopy is effective for diagnosis and the decision-making process regarding treatment.

Cerebral Arteries↗
PubMed2006

Subcutaneous pneumocele associated with ventriculoperitoneal shunt migration into the mechanically occluded colon - case report.

A 62-year-old man presented with shunt failure manifesting as consciousness disturbance 4 years after placement of a ventriculoperitoneal shunt for subarachnoid hemorrhage. Physical examination found subcutaneous pneumocele around the peritoneal catheter extending from the abdomen to the neck. He had undergone pelvic radiation therapy for bladder cancer 2 years before. The peritoneal catheter was removed from the cervical region, and external ventricular drainage and a descending colon stoma for ileus release were positioned. The cerebrospinal fluid was clear and yielded no cultures. No inflammatory changes were seen. He developed carcinomatous peritonitis and died 4 months later. Retrograde colon gas reflux due to catheter perforation into the colon occluded by metastatic sigmoid cancer was probably the cause. Fragility of the wall of colon associated with the prior abdominal radiation therapy might have been a contributing factor. Subcutaneous pneumocele around the peritoneal catheter, i.e. pneumocele within the fibrous sheath surrounding the catheter, is a differential diagnosis to cerebrospinal fluid collection in patients with subcutaneous swelling around the catheter.

Carcinoma↗
PubMed2006

Possibility of using laser spectroscopy for the intraoperative detection of nonfluorescing brain tumors and the boundaries of brain tumor infiltrates. Technical note.

The response of nonfluorescing infiltrating tumors that had been exposed to 5-aminolevulinic acid and irradiated using a laser at a wavelength of 405 nm was analyzed intraoperatively using spectroscopy. Histological analyses demonstrated that neoplastic cells were present in the tissue region that displayed a peak at 636 nm, whereas no neoplastic cells were present in the region that exhibited only the excitation light peak. The authors conclude that the intraoperative use of laser spectroscopy can allow the diagnosis of infiltrating tumor and the detection of boundaries of the infiltrate when standard fluorescence techniques fail.

Adult↗
PubMed2006

Stereotactic radiosurgery as adjuvant treatment for residual solitary fibrous tumor. Case report.

This 50-year-old woman presented with headache and visual disturbance. Neuroimaging results demonstrated a well-demarcated tumor attached to the falx cerebri near the transverse sinus, and the lesion was subtotally removed. Based on histological and immunohistochemical evaluation, a solitary fibrous tumor (SFT) was diagnosed. During the next 32 months, the size of the residual tumor increased slightly at the transverse sinus. Stereotactic radiosurgery (SRS) was performed as an adjuvant treatment. Over the course of the next 4 years the tumor decreased in size. The authors suggest that SRS constitutes good adjuvant treatment for regrowing residual SFTs not amenable to reoperation.

Brain Neoplasms↗
PubMed2006

Shunt infection.

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Age Factors↗
PubMed2006

Regression of an atlantoaxial degenerative articular cyst associated with subluxation during conservative treatment. Case report and review of the literature.

The presence of an atlantoaxial degenerative articular cyst is rare; when present this lesion extends posteriorly to the dens, causing cervicomedullary compressive myelopathy. The authors describe a symptomatic case of this lesion associated with atlantoaxial subluxation in a 76-year-old man. The patient's neurological symptoms resolved and corresponded to a reduction in the size of the cyst. After 8 months of continued conservative treatment, in which the patient wore a Philadelphia collar, the cyst spontaneously regressed. Subsequently, a C1-2 posterior fusion was performed to treat the atlantoaxial subluxation.

Aged↗
PubMed2006

[Vancomycin-resistant Enterococcal meningitis in patients with ventriculoperitoneal shunt: two cases report and review of the literature].

Enterococcal meningitis often occurs in patients with head trauma, cerebrospinal fluid leakage, or shunt devices. Herein, we describe two patients, a 12-year-old boy and a 57-year-old man, who developed meningitis due to vancomycin-resistant Enterococcus (VRE) gallinarum. Both of them had a ventriculoperitoneal shunt for hydrocephalus. The meningitis in one patient was due to fecal transmission of VRE derived from the gut and in the other from prolonged use of vancomycin. In addition, both patients were immunocompromised due to radiotherapy and steroid therapy. The mechanism of developing resistancy and the management of VRE meningitis is discussed.

Child↗