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Biomedical subjects

Kazuhiro Hongo

Publications and source records attributed to Kazuhiro Hongo.

At least 37 records · Page 2Linked to original sources
PubMed2004

Re-occlusion of the superior sagittal sinus after surgical recanalisation.

A 24-year-old woman was struck on the head by a hammer. Because of early signs and symptoms of intercranial hypertension, she underwent surgery for elevation of the depressed fragments which was compressing the superior sagittal sinus (SSS). After operation, the intracranial pressure (ICP) once decreased, but it gradually increased again. After hypothermia and barbiturate therapy, she recovered fully except for partial visual field defect due to brain contusion. A carotid angiogram 28 days after injury revealed complete occlusion of the whole SSS with good collateral circulation. After brain edema had subsided, a follow-up angiogram revealed normal blood flow through the SSS. Elevation of depressed bony fragments is required for a case presenting with early signs and symptoms of intracranial hypertension due to sinus compression. In a case with severe destruction of the SSS, one needs to know that re-occlusion of the dural sinus may occur after surgical recanalisation.

Adult↗
PubMed2004

Spatial learning transiently disturbed by intraventricular administration of ouabain.

The presence of sodium-potassium-adenosine triphosphatase (Na+,K+-ATPase) on the surface of arachnoid cells indicates that active transport of electrolytes and water occurs there. Previously, we accidentally found that intraventricular administration of TGF-beta1 impaired rat spatial learning. Levels of Na+,K+ -ATPase were decreased in arachnoid cells with fibrosis. To characterize the role of the Na+,K+ -ATPase, Wistar rats were intraventricularly administered a total of 200 microl of ouabain, at concentrations of 10(-5), 10(-4) and 10(-3) M, for one week with an osmotic pump, and were examined with a Morris water maze. Latency for reaching the platform did not significantly differ between ouabain-administered rats and controls. Spatial learning was impaired in a dose-dependent manner. Na+,K+ -ATPase activity of arachnoid cells ceased during ouabain administration, and recovered completely three weeks after the end of ouabain administration. The present results suggest that the Na+,K+ -ATPase on the surface of arachnoid cells contributes to maintenance of rat spatial learning.

Animals↗
PubMed2004

Ruptured distal middle cerebral artery aneurysm.

OBJECT: Ruptured distal middle cerebral artery (MCA) aneurysms are uncommon, and their clinical and radiological features are poorly understood. To clarify characteristics of these lesions, the authors undertook a retrospective analysis of nine patients with ruptured distal MCA aneurysms. METHODS: The medical records of patients who underwent surgical repair of ruptured intracranial aneurysms between 1988 and 2002 at Shinshu University Hospital and its affiliated hospitals were retrospectively evaluated. The authors found only nine patients with a ruptured distal MCA aneurysm, and their clinical, neuroimaging, and intraoperative findings were evaluated. CONCLUSIONS: This study of nine patients with distal MCA aneurysms is the largest series to date. Eight lesions were saccular aneurysms that were clipped and the remaining one was a mycotic aneurysm that was trapped. Eight of the nine patients suffered cerebral hematomas with subarachnoid hemorrhage. All patients had good outcomes after obliteration of their aneurysm, although their preoperative condition was not good.

Aged↗
PubMed2004

Functional role of the Na+/H+ exchanger in the regulation of cerebral arteriolar tone in rats.

OBJECT: In vascular smooth-muscle cells, the Na+/H+ exchanger (NHE) is involved in the regulation of [Na+]i, pHi through [H+], and cell volume. Recently, investigations have determined that this exchanger contributes to ischemia and reperfusion injury in coronary circulation. Nonetheless, there is limited information on this glycoprotein in cerebral circulation, especially microcirculation. Thus, the authors in the present study examined the role of NHE in the regulation of cerebral arteriolar tone and its related mechanisms in vitro. METHODS: The internal diameter of isolated pressurized intracerebral arterioles in rats was monitored with the aid of a microscope. To examine the basal activity of NHE two kinds of Na+/H+ exchange inhibitors (FR183998 and 5-[N,N-hexamethylene]amiloride) were administered in the arterioles. Furthermore the authors studied the effects of nitric oxide (NO) synthase inhibitor (NG methyl-L-arginine), Na+/K+ -adenosine triphosphatase (NKA) inhibitor (ouabain), and the Na+/Ca++ exchange inhibitor (SEA0400) on the vascular response induced by either of the Na+/H+ exchange inhibitors. Both of the Na+/H+ exchange inhibitors constricted the arteriole. Subsequent application of NO synthase inhibitor further decreased the diameter of the arterioles. The Na+/H+ exchange inhibitor-induced constriction was completely abolished in the presence of ouabain and SEA0400. CONCLUSIONS: The NHE is active in the basal condition and regulates cerebral arteriolar tone through NKA and the Na+/Ca++ exchanger. Endogenous NO is not related to the activity of NHE in basal conditions.

Amiloride↗
PubMed2004

Degenerative thalamic hamartoma: CT and MR imaging features.

We describe hamartomas of possible thalamic origin. CT revealed marked calcification in the mass lesion, and MR imaging revealed contrast enhancement. Histologically, outgrowth of the glia was observed, but no neoplastic component was confirmed. Immunohistochemical staining was positive for the cell-adhesion factor N-CAM and negative for polysialic acid.

Child↗
PubMed2004

[Treatment of craniopharyngiomas in children].

PURPOSE: The purpose of this article is to assess, in a 25-year retrospective study, the clinical outcome in children with craniopharyngioma. PATIENT AND METHODS: From 1978 to 2002, 12 children younger than 15-year-old underwent treatment with surgery and/or radiotherapy for craniopharyngioma. The clinical course and outcome were reviewed. RESULTS: The median age was 7.3 years (range, 3 to 12 years) at the time of initial surgical resection. With a mean follow-up period of 132 months (range, 29 to 255 months), 1 patient died of tumor progression due to malignant transformation at 205 months after the initial surgery and the overall outcome was good in 11 patients. Out of 12 patients 4 presented a recurrence of their tumor, 2 after an apparently gross total removal. Because of tumor recurrence, 2 received conventional radiation therapy and 3 received gamma knife radiosurgery. There was neither operative mortality nor major complication. All patients required hormonal replacement postoperatively. CONCLUSIONS: The goal in the treatment of craniopharyngiomas is to achieve total removal without morbidity. Our results compared favorably with the previous reports in the literature. MRI follow-up should be performed even in patients whose primary tumor is resected "completely". Suitable combination of open surgery, conventional radiotherapy and gamma knife radiosurgery may result in optimal functional outcome. Recovery from postoperative pituitary dysfunction can be occasionally expected.

Child↗
PubMed2003

Comparison of P2 receptor subtypes producing dilation in rat intracerebral arterioles.

BACKGROUND AND PURPOSE: P2 receptors are important regulators of cerebrovascular tone. However, there is functional heterogeneity of P2Y receptors along the vascular tree, and the functionality of P2Y receptors in small arterioles has not been studied in detail. We investigated the effects of activating P2Y1 and P2Y2 receptors and their underlying dilator mechanisms in rat intracerebral arterioles. METHODS: We used computer-aided videomicroscopy to measure diameter responses from isolated and pressurized rat penetrating arterioles (39.9+/-1.2 microm) to the natural P2 receptor agonist ATP in addition to ADP-beta-S (P2Y1-selective) and ATP-gamma-S (P2Y2-selective) and inhibitors of signaling pathways. RESULTS: Extraluminal application of ATP-gamma-S and ADP-beta-S initiated a biphasic response (initial constriction followed by the secondary dilation) similar to ATP-induced responses. Pyridoxal phosphate-6-azophenyl-2',4'-disulphonic acid (0.1 mmol/L; a P2Y1 receptor antagonist) blocked ADP-beta-S- but not ATP-gamma-S-induced dilation and affected the ATP-mediated dilation at low concentrations. Nomega-Monomethyl-l-arginine partially inhibited the dilation of ATP and ADP-beta-S but not ATP-gamma-S. High K+ saline suppressed the dilation of all agonists. Indomethacin had no effect. CONCLUSIONS: Both P2Y1 and P2Y2 receptors are functionally present in cerebral arterioles. ATP stimulates P2Y1 receptors at low concentrations, while high concentrations of ATP activate P2Y2 in addition to P2Y1 receptors. Nitric oxide is involved in P2Y1 but not P2Y2 receptor activation. Potassium channels play an important role in the regulation of P2Y receptor-mediated dilation.

Adenosine Diphosphate↗
PubMed2003

Aneurysm at the posterior inferior cerebellar artery of extradural origin for preoperative evaluation of safe clipping: case report and review of the literature.

BACKGROUND: As far as we know, 6 cases of extracranial (including craniocervical junction) intradural aneurysms of the posterior inferior cerebellar artery have been previously reported. However, preoperative detailed evaluation of the origin site and a course of the posterior inferior cerebellar artery by means of angiography were not reported in previous papers. CASE DESCRIPTION: We report a rare case of aneurysm of the posterior inferior cerebellar artery, which originated extradurally from the right vertebral artery. A 69-year-old woman experienced a sudden headache 16 years ago and a computed tomography scan showed a subarachnoid hemorrhage around the midbrain. Four-vessel cerebral angiography, however, failed to disclose a source of the hemorrhage. Magnetic resonance angiography incidentally revealed an aneurysm at the craniocervical junction 16 years after the subarachnoid hemorrhage. The aneurysm was exposed and clipped via a suboccipital route. At surgery, it was of no use to apply a temporary clip on the intradural segment of the vertebral artery, because the posterior inferior cerebellar artery was found to enter the intradural space separately from the vertebral artery. The blood flow to such an aneurysm cannot be stopped with this procedure. CONCLUSIONS: Careful neuroimaging study is essential for the accurate diagnosis and successful treatment of such a rare aneurysm.

Aged↗
PubMed2003

Significant elevation of urinary trypsin inhibitor in patients with brain contusion--a preliminary report.

Urinary trypsin inhibitor (UTI) is a protease inhibitor, which is produced in the liver. The correlation between UTI level and head injury has not been evaluated. This study was designed to investigate UTI levels in patients with severe head injury. We measured UTI in the urine of patients with brain contusion. UTI was significantly higher in those patients compared to the control group. The results suggest that UTI may be useful for assessing the severity of head injury and also as a treatment marker in patients with brain contusion.

Adult↗
PubMed2003

Harvesting blood stem cells from cranial bone at craniotomy--a preliminary study.

Primary brain tumors seldom infiltrate into the cranium, even if they are invasive in the central nervous system. In this study, we examined whether blood stem cells can be harvested from cranial bone at craniotomy. Bone marrow cells in cranial bone were counted in 181 craniotomy specimens after staining with hematoxylin and eosin. Marrow volume was measured in 37 specimens using three-dimensional computed tomography (CT). In 10 cases, viable cells collected from very small bone pieces at craniotomy were cultured to examine granulocyte/macrophage colony-forming units (CFU-GM). In 2 cases, bone marrow cells were practically harvested from removed bone at surgery. The weight of bone flap at craniotomy was 35.0 +/- 18.0 g. Bone flap marrow contained 1.5 x 10(9) cells/ml. CT examination showed that bone flap volume was 35.0 +/- 9.0 ml and marrow ratio was 65.1 +/- 13.5%. Thus, at craniotomy, a typical bone flap contained about 3.4 x 10(10) cells. Bone marrow cell count gradually decreased as subject age increased. The bone pieces obtained at craniotomy contained 3.1 +/- 3.4 x 10(6) cells/g, and CFU-GM count was 0.4 x 10(5) cells/g. In one case, we collected 3.4 x 10(8) cells, including 1.8 x 10(6) CFU-GM colonies. In another case, we collected 9.7 x 10(8) cells, including 4.8 x 10(6) CFU-GM colonies. These findings indicate that, at craniotomy, the number of blood stem cells in a typical bone flap is sufficient for autologous blood stem cell rescue.

Adolescent↗
PubMed2003

Internal carotid artery rotation technique to expose an aneurysm neck: technical note.

OBJECTIVE: Full exposure of a neck of an aneurysm is important to obliterate it completely. METHODS: A 51-year-old woman in whom an unruptured aneurysm projecting medially under the optic nerve was incidentally found underwent clipping surgery. The edge of the circumferentially cut distal dural ring was pulled with forceps to rotate the internal carotid artery and to expose the neck of the aneurysm. RESULTS: The neck of the aneurysm was completely obliterated under direct vision. CONCLUSION: This single, neat method exposes the neck of an unruptured paraclinoid aneurysm of the internal carotid artery.

Carotid Artery Diseases↗
PubMed2003

Double-insurance bypass for internal carotid artery aneurysm surgery.

OBJECTIVE: The aim of this article is to present the usefulness of a double-bypass method in the surgical treatment of complex internal carotid artery (ICA) aneurysms. For patients with clippable but complex aneurysms of the ICA having poor collateral circulation, bypass surgery is needed before temporary occlusion of the ICA. We propose a double bypass for safety. METHODS: The superficial temporal artery was anastomosed to the distal cortical branch of the middle cerebral artery (MCA), followed by anastomosis between the radial artery and the inferior trunk of the MCA. For patients with clippable ICA aneurysms, the radial artery was temporarily anastomosed to the inferior trunk of the MCA by raising the ipsilateral forearm to the head after the radial artery was harvested. After the aneurysm had been clipped, the anastomosed radial artery was cut close to the anastomosed site and repositioned back to the original arm. RESULTS: This double-bypass procedure was performed in two patients, and no ischemic complications related to revascularization were observed. Temporary occlusion times of the MCA for superficial temporal artery-to-MCA anastomosis and radial artery-to-MCA anastomosis were 30 and 46 minutes in one patient and 28 and 55 minutes in another. CONCLUSION: This surgical procedure, which we called "double-insurance bypass," can reduce the risk of ischemic complications associated with revascularization of the ICA.

Aged↗
PubMed2003

Characteristics of distal posteroinferior cerebellar artery aneurysms.

OBJECTIVE: Distal posteroinferior cerebellar artery (PICA) aneurysms are rare and have not been well investigated previously. We report our series of 24 patients with 27 distal PICA aneurysms. METHODS: All patients with distal PICA aneurysms that were surgically treated at Shinshu University Hospital and its affiliated hospitals between 1983 and 2001 were reviewed retrospectively. Data relating to clinical, radiological, and intraoperative findings were analyzed. RESULTS: In our series, distal PICA aneurysms reached an incidence of 0.28 and 0.38% of all intracranial aneurysms and ruptured aneurysms, respectively. There were 23 ruptured and 4 unruptured distal PICA aneurysms. Of these, 74.1% were saccular, 7.4% fusiform, and 18.5% dissecting aneurysms. Primarily the telovelotonsillar segment of the PICA was affected. Usually, the surgical outcome was favorable and was influenced by the obstructive hydrocephalus and the preoperative grade. It was sometimes difficult to detect the ruptured distal PICA aneurysm on the initial angiogram, and an extracranial origin of the PICA was sometimes observed. CONCLUSION: This review summarizes the presentation and outcome of a large series of 24 patients with 27 distal PICA aneurysms, and we conclude that distal PICA aneurysms are benign entities compared with vertebral artery-PICA aneurysms. Characteristics that should be considered in the treatment of distal PICA aneurysms are discussed.

Adult↗
PubMed2003

What is the best method for reporting tumor diameter in vestibular schwannoma?

OBJECTIVE: Various methods have been used to report the tumor diameter of vestibular schwannomas. To clarify the most appropriate method to represent the tumor volume, tumor diameters according to various measuring methods were statistically compared with the actual tumor volume. METHODS: Tumor volume was measured by three-dimensional constructive interference in steady state images in 52 unselected vestibular schwannomas. Pearson's correlation coefficient was obtained between the tumor volume and various tumor diameters, such as diameter parallel to the petrous edge (a); a pons-to-petrous diameter (b); ab, a maximum diameter of the portion in the cerebellopontine angle cistern (max CPA); a maximum diameter of the whole tumor (Max); and a diameter through an axis of the internal auditory canal (Axis). The tumors were divided into three groups on the basis of tumor volume, as follows: Group I (small, <0.5 cm(3)), Group II (medium, 0.5-2 cm(3)), and Group III (large, >2 cm(3)). RESULTS: Max and Axis correlated best with the tumor volume in Group I and correlated least with the tumor volume in Group II. Any of these measurements was acceptable in Group III tumors. The max CPA consistently revealed good correlation with the tumor volume in all three tumor groups. CONCLUSION: The max CPA measurement is the simplest and most appropriate way to represent the tumor volume in unselected tumors. Max or Axis is better only when small tumors (<0.5 cm(3) in volume) are being assessed-that is, those with a max CPA of less than 1 cm.

Adult↗
PubMed2003

Protective dural flap for bone drilling at the paraclinoid region and porus acusticus--technical note.

A new method was developed to avoid the risk of injury to the cranial nerves and vessels during intradural bone resection at the paraclinoid region and porus acusticus. The semicircular dural flap is pulled out with a thread over the anterior clinoid process or the porus acusticus. The flap is extended over the underlying structures with a tapered spatula to create adequate space for drilling the bone. The site for drilling was adequately exposed and bone was drilled away smoothly without damaging the underlying vessels and nerves in 10 patients with paraclinoid aneurysms and in seven patients with vestibular schwannomas. This "protective dural flap" method provides wide exposure for drilling, protects the underlying structures, and allows quick inspection during bone resection.

Brain Diseases↗
PubMed2003

Feasibility of using the potassium titanyl phosphate laser with micromanipulators in robotic neurosurgery: a preliminary study in the rat.

OBJECT: Robotic surgery can be used as a novel technology in ultramicrosurgery. A microscopic-manipulator (micromanipulator) system, which has a rigid neuroendoscope and three guiding manipulators, was developed in Japan for less invasive telerobotic neurosurgery. To apply this system in a clinical setting, it is necessary to confirm that it is capable of performing various surgical procedures including cutting, coagulation, and bleeding control. The authors chose the potassium titanyl phosphate (KTP) laser for such procedures. The aim of this paper was to evaluate the feasibility of this system mounted with the KTP laser. METHODS: A prototypical micromanipulator system was tested in rats. Two kinds of in vivo experiments were performed using the KTP laser: coagulation and biopsy. The coagulated lesions were precisely aligned and their maximum depths were proportional to the energy applied during the coagulation experiment. The diagnosable specimens were obtained during the biopsy experiment. The micromanipulator system was able to perform all surgical procedures accurately. There was no complication relating to the use of the micromanipulator system such as brain injury or uncontrollable bleeding. CONCLUSIONS: The results from this study proved that this system works precisely and safely and will become a new neurosurgical tool in managing lesions that are difficult to treat using conventional microsurgery or neuroendoscopic surgery.

Animals↗