Biomedical subjects

K Kurisu

Publications and source records attributed to K Kurisu.

At least 37 records · Page 2Linked to original sources

PubMed2001

Primary neurotransmitters and regulatory substances onto vestibular nucleus neurons.

This review article focused on the primary neurotransmitters involved in transmission from the otolith to the vestibular nucleus (VN), especially in relation to the neurotransmission to the VN neurons (gravity-sensitive neurons) activated by tilt stimulation. The medial vestibular nucleus (MVN) neurons were classified in 8 types (alpha-theta) according to the patterns in response to the clockwise and counterclockwise tilt-stimulations. The tilt-induced firing was inhibited by GDEE (a non-selective glutamate receptor antagonist) and/or atropine (a muscarinic receptor antagonist). Thus, glutamate and/or acetylcholine may serve as the primary neurotransmitters. This conclusion is supported by the previous findings that glutamate exists in the vestibular nerve and is released from the nerve besides the presence of glutamate receptor subtypes in the VN. In addition, acetylcholine induced atropine-reversible firing of MVN neurons, and the enzymes involved in acetylcholine synthesis/metabolism are also found in the VN. Furthermore, serotonin was found to inhibit the MVN neuronal activities via the 5-HT1A receptors. As such, the 5-HT1A agonist, tandospirone, may be effective in preventing and/or treating motion sickness and/or space sickness.

Acetylcholine↗

PubMed2001

Thickening of sphenoid sinus mucosa during the acute stage of pituitary apoplexy.

The authors treated two patients with pituitary apoplexy in whom magnetic resonance (MR) images were obtained before and after the episode. Two days after the apoplectic episodes, MR imaging demonstrated marked thickening of the mucosa of the sphenoid sinus that was absent in the previous studies. The relevance of this change in the sphenoid sinus was investigated. Retrospective evaluations were performed using MR images obtained in 14 consecutive patients with classic pituitary apoplexy characterized by acute onset of severe headache. The mucosa of the sphenoid sinus had thickened predominantly in the compartment just beneath the sella turcica, in nine of 11 patients, as ascertained on MR images obtained within 7 days after the onset of apoplectic symptoms. This condition improved spontaneously in all four patients who did not undergo transsphenoidal surgery. The sphenoid sinus mucosa appeared to be normal on MR images obtained from three patients at the chronic stage (> 3 months after onset). The incidence of sphenoid sinus mucosal thickening during the acute stage was significantly higher in the patients with apoplexy than that in the 100 patients without apoplexy. A histological study conducted in four patients who underwent transsphenoidal surgery during the early stage showed that the subepithelial layer of the sphenoid sinus mucous membrane was obviously swollen. The sphenoid sinus mucosa thickens during the acute stage of pituitary apoplexy. This thickening neither indicates infectious sinusitis nor rules out the choice of the transsphenoidal route for surgery.

Acute Disease↗

PubMed2001

[A case of convexity meningioma en plaque].

We present a case of convexity meningioma en plaque (MEP). A 51-year-old male occasionally suffering from right parietalgia and numbness of left upper limb. An intracranial abnormal mass was pointed out incidentally by the brain check up. Computed tomographic (CT) scans demonstrated a hyperostosis and an enhanced abnormal mass at the right front-parietal region. Magnetic resonant images (MRI) revealed a carpet like tumor extended along the dura mater. Cerebral angiography disclosed feedings from parietal branches of right middle meningeal artery and superficial temporal artery. The tumor was removed subtotally with adjacent dura mater, leaving the portion of close adhesion to the brain parenchyma. Histologic diagnosis was transitional meningioma. Immunohistological stainings showed a high staining index (6.9%) of MIB-1 (Ki-69 antigen) and high expression of metalloproteinase-9 (MMP-9), especially along the dura mater. Convexity MEP is so rare that we review previous reported cases of convexity MEP, and discuss the clinicopathologic features on that.

Antigens, Nuclear↗

PubMed2001

[A case of juvenile pilocytic astrocytoma with unusual neuroimaging features].

We present a case of cerebellar juvenile pilocytic astrocytoma(JPA) with unusual neuroimaging features. The patient was a 14-year-old male who suffered from chronic headaches for a couple of weeks. Plain craniogram showed a decalcification and bulging of the occipital bone. Computed tomography(CT) scans demonstrated low density multiple components with small calcifications in the right cerebellar hemisphere extending to the left. These calcifications were found at the margin of these multi-lobular components. Magnetic resonance imaging(MRI) revealed iso or low intensity on T1 weighted image, and slightly high intensity on T2 weighted image. The lesion indicated more heterogeneous and higher intensity than brain parenchyma on FLAIR imaging, and remarkable higher intensity than brain parenchyma with some small low intensity areas on diffusion weighted imaging. He underwent the complete resection except for the cranial tissue surrounding the pons. Histologic diagnosis was juvenile pilocytic astrocytoma, because of biphasic pattern of bipolar cells and a number of Rosenthal fibers. Generally JPA has sharp and smooth demarcated cysts with well-enhanced mural nodule. It was difficult to diagnose the presented tumor as JPA before operation, since its unusual neuroimaging resembled both dermoid and high grade gliomas.

Adolescent↗

PubMed2001

Falcotentorial meningioma accompanied by temporal lobe hematoma.

We report a case of a falcotentorial meningioma accompanied by hematoma in the temporal lobe. A healthy 51 year-old-female with no history of hypertension presented with sudden onset of consciousness disturbance and right hemiparesis. Computed tomography revealed a hematoma 5.5 cm in diameter surrounded by thick edematous brain in the left temporal lobe and a tumor 3.5 cm in diameter in the pineal region. Bilateral carotid angiography detected occlusion of the Galenic vein and straight sinus. No causative abnormality of hemorrhage was apparent. However, the left basal vein of Rosenthal had disappeared, and anastomotic venous channels could be observed in the medial left temporal lobe, contiguous to the hematoma. Emergency craniotomy failed to detect any abnormality which could cause hemorrhage in the brain parenchyma surrounding the hematoma. Subtotal removal of the tumor, histologically diagnosed as fibrous meningioma, was achieved three months later employing an occipital transtentorial approach. Venous congestion caused by compression due to the tumor was considered to be one of possible causes of the hemorrhage.

Brain↗

PubMed2001

A small asymptomatic intracranial aneurysm in an elderly woman that ruptured soon after discovery.

A 78-year-old woman underwent magnetic resonance (MR) imaging to assess the deterioration of her right hemiparesis initially caused by putaminal hemorrhage that occurred 5 years prior to referral. MR imaging detected an anterior communicating artery aneurysm but no new lesion was seen that might have caused the deterioration was observed. Hemiparesis improved within several days and she was referred for endovascular treatment of the aneurysm. Digital subtraction angiography demonstrated a 4.4 mm long aneurysm at the A1-A2 junction of her left anterior cerebral artery. Information on the risk associated with treatment caused her to hesitate. Three days after discharge and 40 days after the discovery of the aneurysm it ruptured, causing severe subarachnoid hemorrhage. The patient died on the following day.

Aged↗

PubMed2001

[Diagnosis of acute phase of venous infarction by diffusion-weighted image: case report and review of the literature].

Diffusion-weighted imaging (DWI) can diagnose early stage not only of the arterial infarction but also of venous infarction. We successfully diagnosed a case as acute venous infarction by DWI. The patient, an infant of one year and ten months, presented disturbance of consciousness and left hemiparesis two weeks after dehydration and infections. Computed tomographic scan revealed a cerebral hemorrhage in the right parietal lobe. Cerebral angiography revealed no contrast filling of the posterior side of superior sagittal sinus, straight sinus and transverse sinus. DWI demonstrated a large hyperintensity lesion around the hematoma, suggesting venous infarction in the early stage. We thought that venous infarction was caused by secondary extension of thrombus to cerebral cortical veins and deep cerebral veins. External decompression and postoperative hypothermia therapy were performed because of rapidly deteriorating intracranial hypertension. Intracranial hypertension was, however, uncontrollable. The patient died four days after the onset. Diagnosis of the venous infarction by DWI was discussed along with other recent reports. Diffusion hyperintensity was displayed in almost all subjects with acute venous infarction. DWI pattern of venous infarction is more heterogeneous than that of arterial one because pathway from venous obstruction to infarction is complicated.

Cerebral Infarction↗

PubMed2001

[Symptomatic subependymoma of the lateral ventricle in a young female].

We present a case of a symptomatic subependymoma (SE) in a young. The patient was a 20-year-old female who suffered from severe headache and vomiting. Precontrast CT scans revealed a large spotty-calcified isodensity mass lesion in the right anterior lateral ventricle, showing scarce contrast enhancement at the center of the mass and with marked hydrocephalus. MRI demonstrated the lesion as slightly hypo-intensity on T1-weighted image, hyper-intensity on T2-weighted image. On FLAIR imaging, the lesion indicated remarkable hyperintensity and was clearly distinguishable from surrounding brain parenchyma and the cerebrospinal fluid. After Gd-DTPA infusion central vein was revealed, but no tumor enhancement was seen. The tumor was totally extirpated through the transcortical approach. Histological diagnosis was SE, and high MIB-1 staining index (9.3%) was seen. FLAIR imaging is useful for the preoperative diagnosis and the postoperative assessment of SEs.

Adult↗

PubMed2000

Molecular cloning and characterization of a novel gene, CORS26, encoding a putative secretory protein and its possible involvement in skeletal development.

We cloned a novel mouse cDNA, CORS26 (collagenous repeat-containing sequence of 26-kDa protein), encoding a secretory protein by suppression subtractive hybridization between transforming growth factor-beta1-treated and untreated C3H10T1/2 cells. The deduced amino acid sequence of CORS26 consists of 246 amino acids with a secretory signal peptide and contains a collagenous region (Gly-X-Y repeats) at the NH(2) terminus and a complement factor C1q globular domain at the COOH terminus. CORS26 is structurally similar to C1q and to adipocyte-specific protein Acrp30. Transfection analysis suggested that CORS26 is a secretory protein. Northern blot analysis revealed that CORS26 mRNA was present at high levels in rib growth plate cartilage and at moderate levels in kidney of adult mice. CORS26 mRNA was not detected in NIH3T3 cells, BALB/3T3 cells, C3H10T1/2 cells, or osteoblastic MC3T3-E1 cells by reverse transcription-polymerase chain reaction analysis. In situ hybridization of mouse embryos between 13 and 15 days postcoitus revealed relatively high levels of CORS26 mRNA in condensed prechondrocytic cells of cartilage primordia and developing cartilages. However, CORS26 mRNA were undetectable in mature chondrocytes. Furthermore, overexpression of CORS26 enhanced the growth of C3H10T1/2 cells in vitro. The present findings suggest that the CORS26 gene may play an important role in skeletal development.

3T3 Cells↗

PubMed2000

Recurrence of meningiomas.

BACKGROUND: Macroscopic total resection with removal of involved dura and bone does not always prevent the recurrence of meningioma of histologically benign subtype. Many causative factors have been investigated, although the mechanism of recurrence remains unclear. Vascular endothelial growth factor (VEGF) is a key factor in meningiomas neovascularization, and the authors investigated whether VEGF expression can predict the recurrence of histologically benign meningiomas after macroscopic total resection. METHODS: Fifty-four patients with supratentorial convexity meningiomas were investigated at least 3 years after surgery or until tumor recurrence to clarify risk factors for recurrence. Patients were restricted to Simpson Grade 1 resection only, and the authors excluded multiple meningiomas, neurofibromatosis, and atypical and anaplastic meningiomas. Correlation between recurrence and the following factors were statistically analyzed: age, gender, tumor volume, tumor shape, bone change, brain edema, vascular supply, histologic subtype, MIB-1 labeling index (LI), and VEGF expression. RESULTS: Of the 54 patients with meningioma, 34 were positive (24: +1; 10: +2) for VEGF, and 20 were negative. Six (11.1%) meningiomas recurred during the follow-up period. Multivariate analysis revealed that high levels of expression of VEGF constituted the most useful predictor of recurrence (P = 0.005), followed by high MIB-1 LI (P = 0.039). The other factors were not significant. The tumor recurrence, when it occurred, was within the brain and not durally based. CONCLUSIONS: The current results suggest that high levels of VEGF expression are significantly related to the recurrence of meningioma. VEGF secretion from microscopic residue remaining after surgery may induce neovascularization, which promotes the recurrence of meningioma.

Adult↗

PubMed2000

Effects of neonatal injury of the inferior alveolar nerve on the development and regeneration of periodontal nerve fibers in the rat incisor.

Our previous study showed that the migration of terminal Schwann cells occurred in the periodontal ligament of the rat lower incisor following transection of the inferior alveolar nerve (IAN) in the adult animals [Y. Atsumi, K. Matsumoto, M. Sakuda, T. Maeda, K. Kurisu, S. Wakisaka, Altered distribution of Schwann cells in the periodontal ligament of the rat incisor following resection of the inferior alveolar nerve: An immunohistochemical study on S-100 proteins, Brain Res. 849 (1999) 187-195]. The aim of the present study was to investigate the effects of neonatal transection of the IAN on the regeneration of axon elements and Schwann cells in the periodontal ligament of the rat lower incisor. Following transection of IAN at post-natal day 5 (PN 5d), when the numbers of both axon elements and the terminal Schwann cells were very small, regenerating nerve fibers appeared between post-injured days 7 (PO 7d) and PO 14d, and increased in number thereafter gradually. Although the terminal morphologies of regenerated Ruffini endings became identical to those of the adult animals by PO 54d, the number of regenerated PGP 9.5-IR nerve fibers did not recover the adult levels even by PO 56d. A small number of Schwann cells migrated into the shear zone, the border between the alveolus-related part (ARP) and the tooth-related part (TRP), but did not enter into the TRP. Following transection of the IAN at PN 14d or PN 28d, when clusters of apparent terminal Schwann cells could be recognized, axon regeneration started around PO 5d. Individual axon terminals of the regenerating Ruffini endings ramified and became identical to those of the adult animals around PO 28d, but the number of regenerated Ruffini endings was smaller than that of the adult animals. Similar to the adult animals, the migration of Schwann cells into the shear zone and TRP occurred, and disappeared prior to the completion of the axonal regeneration. The present results indicate that the migration of the Schwann cells into TRP during the regeneration of the periodontal nerve fibers following nerve injury to the IAN depends on the maturation of the terminal Schwann cells of the periodontal Ruffini endings, not on post-operative time.

Age Factors↗

PubMed2000

Transcription factor ERG variants and functional diversification of chondrocytes during limb long bone development.

During limb development, chondrocytes located at the epiphyseal tip of long bone models give rise to articular tissue, whereas the more numerous chondrocytes in the shaft undergo maturation, hypertrophy, and mineralization and are replaced by bone cells. It is not understood how chondrocytes follow these alternative pathways to distinct fates and functions. In this study we describe the cloning of C-1-1, a novel variant of the ets transcription factor ch-ERG. C-1-1 lacks a short 27-amino acid segment located approximately 80 amino acids upstream of the ets DNA binding domain. We found that in chick embryo long bone anlagen, C-1-1 expression characterizes developing articular chondrocytes, whereas ch-ERG expression is particularly prominent in prehypertrophic chondrocytes in the growth plate. To analyze the function of C-1-1 and ch-ERG, viral vectors were used to constitutively express each factor in developing chick leg buds and cultured chondrocytes. We found that virally driven expression of C-1-1 maintained chondrocytes in a stable and immature phenotype, blocked their maturation into hypertrophic cells, and prevented the replacement of cartilage with bone. It also induced synthesis of tenascin-C, an extracellular matrix protein that is a unique product of developing articular chondrocytes. In contrast, virally driven expression of ch-ERG significantly stimulated chondrocyte maturation in culture, as indicated by increases in alkaline phosphatase activity and deposition of a mineralized matrix; however, it had modest effects in vivo. The data show that C-1-1 and ch-ERG have diverse biological properties and distinct expression patterns during skeletogenesis, and are part of molecular mechanisms by which limb chondrocytes follow alternative developmental pathways. C-1-1 is the first transcription factor identified to date that appears to be instrumental in the genesis and function of epiphyseal articular chondrocytes.

Alkaline Phosphatase↗

PubMed2000

Epileptic seizures induced by N-acetyl-L-aspartate in rats: in vivo and in vitro studies.

Tremor rat (tm/tm), the parent strain of spontaneously epileptic rat (SER: zi/zi, tm/tm), exhibits absence-like seizures characterized by 5-7 Hz spike-wave-like complexes on cortical and hippocampal electroencephalograms (EEG) after 10 weeks of age, prior to development of convulsive seizures. Recently, this animal model has been demonstrated to display a genomic microdeletion within the critical region of tm, where aspartoacylase hydrolyzing N-acetyl-L aspartate (NAA) is located, besides showing the ability to accumulate NAA in the brain. Therefore, the present study was performed to determine the involvement of NAA in the induction of epileptic seizures. When NAA (4 micromol) was applied intracerebroventricularly (i.c.v.) to normal Wistar rats, 4-10 Hz polyspikes and/or spike-wave-like complexes followed by absence-like seizure before persistent 1-5 Hz waxing high-voltage after-discharges were observed on cortical and hippocampal EEG. At a higher dose (8 micromol), NAA induced convulsive seizures. The absence-like seizures with polyspikes and/or spike-wave-like complexes on the EEG were also observed with i.c.v. NAA in premature tremor rats without seizures. The NAA-induced seizures in normal rats were antagonized by i.c.v. glutamic acid diethyl ester, a non-selective glutamate receptor antagonist. In addition, NAA applied to the bath rapidly induced a long-lasting depolarization concomitantly with repetitive firings in hippocampal CA3 neurons of normal rat brain slice preparations. These findings suggest that NAA is involved in the induction of absence-like seizures and/or convulsion, probably via glutamate receptors.

Animals↗

PubMed2000

Calbindin D28k-like immunoreactivity during the formation of the enamel-free area in the rat molar teeth.

Previous studies have demonstrated the presence of calbindin D28k in the ameloblasts derived from the inner enamel epithelium. The occlusal surfaces of the rodent molars partly lack the enamel covering, which is referred to as enamel-free area (EFA). In the present study, we compared the immunohistochemical localization of calbindin D28k-like immunoreactivity (CB-LI) in the cells at the EFA (EFA cells) and ameloblasts of the rat molar teeth at the light microscopic level. CB-LI was strong in the ameloblasts of the presecretory through the protective stages, while it was faint at the late secretory to transitional stages. However, some mature ameloblasts lacked the immunoreactivity. On the other hand, the majority of EFA cells showed distinct polarization and elongation that were absent in few cells at the early stage of EFA formation. At all stages, the EFA cells adjacent to the ameloblasts showed CB-LI, however, some cells adjacent to the mature ameloblasts lacked the reaction. Intensive CB-LI was demonstrated in EFA cells at the reduced enamel epithelium. These immunohistochemical findings suggest EFA cells have cytochemical properties similar to those of ameloblasts.

Ameloblasts↗

PubMed2000

Immunohistochemical detection of heme oxygenase-2 in the periodontal Ruffini ending of the rat incisor.

The present study was carried out to examine the occurrence of heme oxygenase-2 (HO-2) in the periodontal ligament of the rat incisor. HO-2-like immunoreactive (-IR) structures showed dendritic profiles, resembling the Ruffini endings, in the alveolar half of the ligament of rat incisor. Neither thin nerve fibers nor perivascular nerve fibers displayed HO-2-like immunoreactivity (-LI). No non-neural elements exhibited HO-2-LI. Electron microscopy revealed that immunoreactions were diffusely observed in the axon terminals of the Ruffini endings, but neither terminal Schwann cells nor Schwann sheaths contained immunoreactions for HO-2. Both most neurons in the trigeminal ganglion and trigeminal mesencephalic nucleus showed HO-2-LI. The presence of HO-2 in the periodontal Ruffini endings and its absence in the periodontal thin nerve fibers suggest the involvement of carbon monoxide produced by HO-2 in mechanoreception in the periodontal ligament.

Animals↗

PubMed2000

Dissecting aneurysm of the peripheral posterior inferior cerebellar artery.

Dissecting aneurysms of intracranial posterior circulation have recently been shown to be less uncommon than previously thought. However, those involving the posterior inferior cerebellar artery (PICA) and not vertebral artery at all are extremely rare. We report here a case of a patient with a dissecting aneurysm of the lateral medullary segment of PICA which presented as subarachnoid haemorrhage. The aneurysm was treated by trapping surgery and the distant PICA was anastomosed to the occipital artery. The patient showed a slight ataxia immediately after surgery but recovered fully. Recovery from immediately postoperative cerebellar symptoms due to intra-operative ischemia seemed to be due largely to recovery of flow in the region of cortical branches of PICA.

Anastomosis, Surgical↗

PubMed2000

Transsphenoidal "cross court" approach using a slightly modified speculum to reach pituitary adenomas with lateral growth.

BACKGROUND: The purpose of this study was to evaluate the usefulness of an oblique "cross court" transsphenoidal approach using a speculum with slightly modified projections for pituitary adenomas showing lateral extension. METHOD: The projection of the speculum on the side of the cavernous lesion was shortened by 5 mm. The tip of the longer projection was placed in the sphenoid sinus, while the end of the shorter projection was placed on the concha sphenoidalis. An oblique transsphenoidal view was then easily obtained by opening the speculum. The contralateral nasal incisura had to be widened in some cases to achieve a more oblique view. FINDINGS: Twenty-eight patients diagnosed with pituitary adenoma showing lateral growth underwent adenomectomy under direct observation of the medial portion of the cavernous sinus using this approach. Postoperative normalization of hyperendocrinopathy or gross total removal of the tumour was achieved in the majority of patients. INTERPRETATION: An oblique transsphenoidal approach using this speculum and contralateral minor maxillary osteotomy afforded a direct view of the medial cavernous sinus, sufficient for the removal of adenomas showing minor to moderate lateral growth.

Adenoma↗

PubMed2000

Telomerase activity and the expression of telomerase components in pituitary adenoma with malignant transformation.

BACKGROUND: Telomerase activity responsible for cellular immortality may participate the development of human cancers. Telomerase is a multisubunit ribonucleoprotein composed of at least three components: hTERT, hTERC, and TEP1. This is the first report showing telomerase activity and telomerase component expression in pituitary adenoma with histological malignant transformation. DESCRIPTION: A 16-year-old male with a prolactin-producing pituitary adenoma with metastasis is presented. The patient underwent three partial resections of an intra- and suprasellar lesion over a 2-year period and received focal irradiation. Eight years after the first admission, a metastatic lesion to the subarachnoid space around the medulla oblongata was detected and the lesion was resected as the fourth operation. Furthermore, the suprasellar lesion showed regrowth and partial resection was performed as the fifth operation. The last two specimens were diagnosed as pituitary carcinoma. Radiotherapy with gamma knife was performed for the residual suprasellar lesion and a new lesion in the left temporal lobe after the fifth operation. Telomerase activity was examined by TRAP/TRAP-HPA methods, qualitatively and quantitatively. Telomere length was examined by Southern blot analysis, and the expression of telomerase components (hTERT, hTERC, and TEP1) was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The MIB1 index, telomerase activity, and hTERT expression increased according to histologic malignancy chronologically in this patient. None of the specimens showed immunoreactivity for p53, EGFR, or bc12. No telomerase activity was detected in pituitary adenomas without malignant transformation, other benign brain tumors, or normal brain tissues. CONCLUSION: We report a patient with pituitary adenoma transforming to carcinoma. The tumor cells acquired immortality and revealed malignant transformation during the course of the disease, that was proved by an increase of telomerase activity and hTERT expression.

Adenoma↗