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Biomedical subjects

T Kawase

Publications and source records attributed to T Kawase.

At least 109 records · Page 6Linked to original sources
PubMed1999

Zygomatic arch cracking for cosmetic improvement: technical note.

We describe a simple cracking method for removing the zygomatic arch. The drilling line of the zygomatic arch is partially drilled from the back, and the surface is left undrilled. The zygomatic arch is cracked during its removal in order to secure its position for later fixation. Dead bone spaces can be avoided by this method and the zygomatic arch can be replaced in its original position. By adding this procedure to the standard technique, this cracking method is a simple, safe and useful way to achieve better cosmetic results.

Humans↗
PubMed1999

Profound hearing loss attributable to cochlear nerve disease: diagnosis with combination of otoacoustic emission and magnetic resonance imaging.

OBJECTIVE: To detect the causes of deafness based on the combined findings of auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAEs), and three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) magnetic resonance imaging (MRI). STUDY DESIGN: Retrospective review of the medical records of 13 patients with unilateral profound hearing loss since childhood. METHODS: Subjects were tested with pure-tone audiometry, ABR, DPOAEs, and 3DFT-CISS imaging. RESULTS: No significant components of ABR were observable in any of the deaf ears. In 10 cases, the cochlear nerves of the deaf ears were found to be as normal as the healthy sides by 3DFT-CISS imaging, and no significant levels of DPOAEs were recorded. In the other three cases, no apparent cochlear nerves were identified by 3DFT-CISS imaging. Although no significant levels of DPOAEs were observable in two cases with cochlear nerves invisible by the MRI study, almost the same level of DPOAEs as that in the healthy side was recorded in the last case. CONCLUSIONS: In the last particular case, the cochlear nerve seemed to be mainly responsible for the profound deafness. 3DFT-CISS imaging in combination with preexisting audiological measures may provide direct evidence for the cochlear nerve disease. steady state, internal auditory canal, cochlear nerve disease.

Audiometry, Pure-Tone↗
PubMed1999

In vivo rat closed spinal window for spinal microcirculation: observation of pial vessels, leukocyte adhesion, and red blood cell velocity.

OBJECTIVES: An in vivo closed spinal window technique in rats was designed for observing the spinal microcirculation, such as the change of vessel diameter, leukocyte adhesion, and red blood cell (RBC) velocity, which has been very rarely examined in vivo in the spinal cord. METHODS: We made a very precise closed spinal window with a laminectomy at the C5 level using a dental acrylic resin and a cover glass (7 mm in diameter). Through this closed window, the dorsal surface of the rat cervical cord was observed with a video microscope, and the fluorescent images of rhodamine 6G-labeled leukocytes and fluorescein isothiocyanate-labeled RBCs were recorded and analyzed with a silicon-intensified target tube camera (30 frames/s) and an image-intensified high-speed video camera system (1000 frames/s). RESULTS: During CO2 inhalation, the pial arterioles responded with vasodilation of 12.4+/-10.4% (P<0.01) in 11 arterioles of seven rats. The adhering leukocytes significantly increased in 41 venular segments of seven rats after superfusion of the neutrophil chemoattractant, N-formyl-methionine-leucine-phenylalanine solution for 15 minutes (P<0.001) but not after superfusion of only artificial cerebrospinal fluid for 15 minutes. During these experiments, no adhering leukocyte was seen in the pial arterioles. Fluorescein isothiocyanate-labeled RBCs look like shooting stars in arterioles with silicon-intensified target tube camera processing at 30 frames per second, but individual fluorescein isothiocyanate-labeled RBCs could be recognized frame by frame with the image-intensified high-speed video camera system. In 13 arterioles of four rats, the RBC velocity was 5.3+/-2.0 mm per second. CONCLUSION: This closed spinal window technique in rats is available and applicable for the study of the spinal microcirculation, such as the pathophysiology of a secondary injury.

Animals↗
PubMed1999

Calcitonin gene-related peptide acts as a mitogen for human Gin-1 gingival fibroblasts by activating the MAP kinase signalling pathway.

In many peripheral tissues, calcitonin gene-related peptide (CGRP) is released from peptidergic sensory nerve fibres and acts like a growth factor during tissue development and regeneration. However, the ability of CGRP to influence gingival tissue has not been studied. To address this question, we have now examined the effects of CGRP on the proliferation of human gingival fibroblasts (Gin-1) in vitro. Gin-1 cells have approximately 3100 specific CGRP-binding sites with a Kd of 38.6 pM on their surface. Treatment with CGRP (0.1-100 nM) significantly stimulated cell proliferation in a dose-dependent manner, with maximal effects at 1-10 nM CGRP after 2 d. As one early cellular response to CGRP, p44-MAPK protein (also known as the extracellular signal response kinase [ERK]) was tyrosine- and threonine-phosphorylated within 2 min, and this phosphorylation was sustained for at least 1 h. The dose-response curve of MAPK activation was very similar to that observed for CGRP's stimulation of cell proliferation. In addition, CGRP's activation of MAPK stimulated its ability to phosphorylate the Elk-1 transcription factor. When cells were pretreated with PD98059, a selective inhibitor of MAPK kinase (also known as MEK), CGRP not only failed to induce phosphorylation of MAPK but also failed to stimulate Gin-1 cell proliferation. Our present data indicate that CGRP rapidly activates the MAPK signalling pathway, an effect which consequently stimulates the proliferation of gingival fibroblasts. Our data demonstrate specific cellular responses to CGRP by gingival fibroblasts and support the possibility that CGRP acts as a targeted local factor in the regulation of development, generation and/or regeneration of gingival tissues.

Analysis of Variance↗
PubMed1999

Cytokine secretion of periodontal ligament fibroblasts derived from human deciduous teeth: effect of mechanical stress on the secretion of transforming growth factor-beta 1 and macrophage colony stimulating factor.

The periodontal ligament may play an important role in tooth eruption, root development and resorption. The tissue physiologically receives mechanical force during mastication. We focused on the effects of intermittent mechanical strain on the cytokine synthesis of periodontal ligament (PDL) fibroblasts in vitro. The cells were derived from human periodontal ligament of deciduous teeth (HPLF-Y) and permanent teeth (HPLF). The two kinds of PDL cells and human gingival fibroblasts (HGF) were cultured in flexible bottomed culture plates. The cells were mechanically stretched at 5% elongation, 3-cycles/min for 24 h on d 7 in culture using a Flexercell strain unit. After the stretching, we measured DNA content and alkaline phosphatase activity in the cell layer, transforming growth factor beta 1 (TGF-beta 1) and macrophage colony stimulating factor (M-CSF) contents in the conditioned medium. The TGF-beta 1 level in the conditioned medium of HPLF was significantly higher than that of HPLF-Y and HGF. It was stimulated by mechanical stretching only on HPLF, whereas no significant effect was observed on HPLF-Y and HGF. M-CSF secretion was inhibited by the stretching on all of HPLF, HPLF-Y and HGF. 1 alpha, 25 dihydroxy vitamin D3 (D3) stimulated M-CSF secretion into the culture medium of both HPLF and HPLF-Y, but the stretching inhibited M-CSF secretion and completely blocked the enhancement by D3. These data suggest that periodontal ligament cells synthesize and secrete the molecules as autocrine or paracrine factors that affect bone remodelling and root resorption and the level of those factors change in response to mechanical stress.

Alkaline Phosphatase↗
PubMed1999

Effects of moderate hypothermia on leukocyte- endothelium interaction in the rat pial microvasculature after transient middle cerebral artery occlusion.

Background and Purpose--It has been demonstrated that moderate hypothermia attenuates brain damage, but the mechanism whereby this is achieved has not been clearly shown. Recently, the role of leukocytes as mediators of secondary brain damage after brain ischemia has been discussed. The aim of this study is to examine the effects of moderate hypothermia on leukocyte-endothelium interaction in the rat pial microvasculature after transient middle cerebral artery occlusion (MCAO). Methods--Rhodamine 6G-labeled leukocytes in brain surface were visualized with intravital fluorescence videomicroscopy through a closed cranial window. We analyzed the number of leukocytes adhering to the venular and arteriolar endothelium before ischemic insult and up to 3 hours after reperfusion. Rats were divided into 4 experimental groups. Group I (n=6) consisted of sham-operated animals. Groups II (n=6) and III (n=6) received left MCAO for 1 hour under normothermia (36 degrees C to 37 degrees C, group II) and under moderate hypothermia (30 degrees C to 32 degrees C, group III). Group IV (n=4) received left common carotid artery occlusion for 1 hour under normothermia. Results--The number of adhering leukocytes in venules in groups II and IV increased significantly (P<0.001) after reperfusion compared with the group I, but that in group III did not increase significantly (P>0.05). The number of adhering leukocytes in arterioles in group II increased significantly (P<0.01) compared with the other groups, although the adhering leukocytes were not as numerous as those seen in venules. Conclusions--It is demonstrated that hypothermia attenuates adhering leukocytes in venules and arterioles after reperfusion of MCAO. The inhibition of the leukocyte function may be an important factor in the neuroprotective effect of hypothermia.

Animals↗
PubMed1999

Trigeminal neurinomas extending into multiple fossae: surgical methods and review of the literature.

OBJECT: Since 1974, 27 patients with trigeminal neurinomas (TNs) have been treated at Keio University Hospital and ancillary institutes. In the present study the clinical features and developmental patterns of these 27 cases are analyzed, and the clinical features of 402 cases reported in the literature are reviewed. Based on the analysis of the developmental patterns of the TNs, the surgical strategy for a one-stage removal of TNs involving multiple fossae is described. METHODS: Trigeminal neurinomas are classified into six types according to tumor location. Types M, P, and E are tumors involving a single compartment, that is, the middle fossa, posterior fossa, or extracranial space, respectively. Types MP (middle and posterior fossae), ME (middle fossa and extracranial space), or MPE (middle and posterior fossae and extracranial space) are tumors involving multiple compartments. Advances in neuroimaging technologies, such as magnetic resonance imaging, have revealed a high incidence of TNs extending into multiple fossae, namely 36.2% in cases reported since 1983 and 59% in the authors' series. All but one of the most recent 19 patients in this series underwent skull base surgery, whereas the remaining nine patients were surgically treated via the conventional subdural approach. The rate of total tumor removal and the clinical outcome were significantly better in those patients treated by skull base surgery than those treated by conventional surgery. CONCLUSIONS: The TNs extending into multiple fossae can be totally removed using the following single-stage surgical techniques: Type MP by the anterior transpetrosal approach; Type ME by the zygomatic or orbitozygomatic infratemporal approach; and Type MPE by the zygomatic transpetrosal approach. In 12 of 13 cases involving multiple fossae in this series, total tumor removal was achieved using single-stage skull base surgery.

Adolescent↗
PubMed1999

[The use of computers and networking in the neurosurgical field].

Due to the improvements in computer and network technology, we are able to use medical information easily and safely on the network in medical institutions. In our department, we constructed and used an original Intranet with light fibers. The network links the outpatient room, ward, operation room, staff room and the examination room. Moreover, many computers and medical instruments are connected to the Intranet. Since our original Intranet has no connection with the outside network, we are able to access the patient's medical information safely. Using access management of identity and a password on the server, the client can present the medical information with sound and movie upon request of the patients and their families, medical students, nurses and doctors. Doctors can also search and input the patient's most recent medical information on a network database of every client. By linking the examination machine and operation aided instrument to the Intranet, we were able to forward the patient's medical information to the operation aided instrument easily and quickly. Furthermore, we will be able to perform tele-medicine and tele-operation in the near future: that is, the medical staff can guide the neurosurgical operation outside of the operation room with a microscope and computer view using picture mutual communication devices. By strict access to the management of our Intranet, we are able to use the medical information effectively for patient's treatment, operation, education and study on the network with no connection to the outside network.

Databases, Factual↗
PubMed1999

[A case of enlarged infundibular dilatation diagnosed by vertebral angiograms with carotid compression and neuroendoscope].

A case of enlarged infundibular dilatation diagnosed by vertebral angiograms with carotid compression was reported. A 57-year-old woman suffered from headache. She underwent MRA which revealed left internal carotid artery aneurysm. Left common carotid angiograms suggested a left saccular internal carotid artery aneurysm (4 mm x 6 mm) without a posterior communicating artery. However, it was confirmed to be an enlarged infundibular dilatation on left vertebral angiograms with carotid compression. It was confirmed at operation microscopically and neuroendoscopically, and the dilatation was treated by coating. When carotid angiograms reveal no posterior communicating artery, it is difficult to differentiate the origin of posterior communicating artery from internal carotid artery-posterior communicating artery junction aneurysms. Vertebral angiograms with carotid compression is useful for the differentiation for the exact diagnosis.

Aneurysm↗
PubMed1999

[Aortic valve papillary fibroelastoma in a patient with mitral valve regurgitation].

Papillary fibroelastoma is a rare cardiac tumour. We describe a patient with mitral valve regurgitation and aortic valve papillary fibroelastoma. The patient was 62-year-old woman. She was referred to us for surgical treatment of mitral valve. Preoperative echocardiography showed rheumatic mitral valve regurgitation (Sellers grade III) and it also demonstrated mobile masses of the aortic valve. At operation, mitral valve was repaired by a posterior annuloplasty. Through the aortotomy, small tumors were found to be attached to each cusps of the aortic valve and they were successfully removed. The histopathologic diagnosis was papillary fibroelastoma of the aortic valve. The postoperative course was uneventful.

Aortic Valve↗
PubMed1999

Effects of mechanical stress on the mRNA expression of S100A4 and cytoskeletal components by periodontal ligament cells.

The periodontal ligament (PDL) functions under constant mechanical stress, and PDL cells obviously control PDL functions under such conditions. We have previously found that the mRNA expression of the Ca2+-binding protein S100A4 and beta-actin is higher in the PDL from erupted teeth than in the PDL from teeth under eruption. This suggested a role for S100A4 in the response of PDL cells to mechanical stress, possibly by coupling Ca2+ and the cytoskeletal system. In the present study, we investigated the direct effects of cyclical stretching on the mRNA expression of S100A4 and two cytoskeletal components (beta-actin and alpha-tubulin) by PDL cells. In Northern blotting analysis, the expression of S100A4, beta-actin, and alpha-tubulin mRNAs was higher in the PDL from fully erupted and functional bovine teeth than in partially erupted ones. Similarly, when bovine PDL cells were mechanically stimulated by means of the Flexercell Strain Unit, the expression of S100A4, beta-actin, and alpha-tubulin mRNAs increased over the control levels. The results of our present study indicate that S100A4 is involved in the responses of PDL cells to mechanical stress possibly by coupling Ca2+ to the cytoskeletal system in these cells.

Actins↗
PubMed1998

Expression of the neural cell adhesion molecule in astrocytic tumors: an inverse correlation with malignancy.

BACKGROUND: Cell adhesion molecules are among the key factors in the development of the malignant potential of brain tumors. The aim of this study was to investigate the expression of the neural cell adhesion molecule (NCAM) in human astrocytic tumors and assess any relationship between NCAM expression and the degree of malignancy. METHODS: The expression of NCAM was examined in 52 astrocytic tumors by Western blot analysis. From them the authors selected 23 adult supratentorial ordinary astrocytic tumors and performed quantitative Western blot analysis for each isoform (NCAM 172-180, NCAM 145, NCAM 125-130) to investigate any correlation between the expression of each NCAM isoform and the histologic and biologic malignancy (histology, proliferating cell indices [PCIs] determined by MIB-1 immunohistochemistry, and manifestation on magnetic resonance images [MRIs]). Immunohistochemistry with antihuman NCAM monoclonal antibody was also performed on the tumors from which cryostat sections were available. RESULTS: Most of the astrocytomas and anaplastic astrocytomas revealed 3 bands at 180, 145, and 125-130kD, whereas in glioblastomas the bands tended to diminish. The expression of each NCAM isoform in astrocytic tumors decreased in proportion to the progression of the histologic malignancy, and the results were also corroborated by immunohistochemical evaluation. An inverse correlation was also observed between the amount of NCAM expression and MIB-1 PCIs. NCAM expression was hardly detectable in those tumors with highly invasive manifestation on MRIs. CONCLUSIONS: To the authors' knowledge, this study provides the first direct evidence that NCAM is down-regulated in the development of the malignancy of astrocytic tumors; and it is suggested that reduced NCAM expression might be involved in the development of biologic malignancy.

Adult↗
PubMed1998

Measurement of RBC velocities in the rat pial arteries with an image-intensified high-speed video camera system.

The mean centerline red blood cell (RBC) velocity of the rat pial artery was measured using an image-intensified high-speed (1000 frames/s) video camera system and RBCs labeled with fluorescein isothiocyanate (FITC). Some investigations measuring RBC velocity have been made in most organs, but the RBC velocity of the pial artery has not yet been measured with this system using FITC labeled RBC. After recording the emission of the FITC labeled RBC through a closed cranial window using this system, the authors analyzed the videotape. The movement of each individual RBC for several milliseconds over a distance of 50 microm could be pursued. The mean centerline RBC velocity in normal rats varied between 1.0 and 9.0 mm/s (most of the measurements we taken in vessels ranging between 20 and 80 microm in diameter). As the diameter of the pial artery becomes smaller, the blood flow rate (pi x (diameter/2)2 x (mean centerline velocity/1.6)) tends to become smaller. During CO2 inhalation, the pial artery diameter, mean centerline RBC velocity, and blood flow rate increased with statistical significance. Mean centerline RBC velocities in the cerebral microcirculation could not be measured directly with accuracy using the older methods (30 frames/s). However, this method is useful for investigation of the cerebral microcirculation and is considered to be applicable for studying the behavior of leukocytes or platelets, which will be examined in a subsequent study.

Animals↗
PubMed1998

Up-regulation of inducible nitric oxide (NO) synthase and NO production in HL-60 cells stimulated to differentiate by phorbol 12-myristate 13-acetate plus 1,25-dihydroxyvitamin D3 is not obtained with dimethylsulfoxide plus 1,25-dihydroxyvitamin D3.

In previous studies we found that the calciotropic hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] augments the action of either prostaglandin E1 (PGE1) or NaF to induce differentiation of human promyelocytic HL-60 cells, a process that features increased generation of nitric oxide (NO) via up-regulation of inducible nitric oxide synthase (iNOS). We have now examined the short-term interaction of 1,25(OH)2D3 with phorbol 12-myristate 13-acetate (PMA) and dimethylsulfoxide (DMSO) in these cells. PMA (100 nM) alone generally up-regulated several classical indices of macrophagic differentiation and stimulated cellular production of interleukin (IL)-1alpha, IL-6, tumor-necrosis factor (TNF)-alpha, PGE2, and NO. Increased generation of NO primarily resulted from increased expression of cellular iNOS. When 1,25(OH)2D3 (10 nM) was added to PMA treatments, most PMA-induced changes, particularly its effects to up-regulate iNOS-dependent NO production and change cell morphology, were multiplicatively augmented. In contrast, DMSO (1.3%) alone, an inducer of granulocytic differentiation, increased cytokine production, but failed to stimulate NO production or induce iNOS. In contrast to its striking interaction with PMA, 1,25(OH)2D3 could not augment DMSO's differentiative effects. Changes in cellular cytokine production were eliminated as the driving force in HL-60 differentiation when specific neutralizing antibodies failed to produce any attenuation of iNOS up-regulation or of the shifts in cell morphology. However, indomethacin (30 microM) blocked the synergistic interaction between 1,25(OH)2D3 + PMA to shift cell morphology and stimulate NO production. Subsequently adding PGE2 (1 ng/ml) to indomethacin-treated cells restored the ability of 1, 25(OH)2D3 + PMA to interactively increase cellular NO production, but failed to fully replicate the strong shift in cell morphology typical of PMA + 1,25(OH)2D3 treatments. Our findings suggest that interaction between 1,25(OH)2D3 and PMA to induce macrophagic differentiation increases iNOS-dependent NO production by a mechanism involving a cyclooxygenase product(s), possibly PGE2.

Calcitriol↗
PubMed1998

Immunohistochemical examination of c-Met protein expression in astrocytic tumors.

Hepatocyte growth factor/scatter factor (HGF/SF), which has various physiological functions, and its receptor c-Met, the human c-met proto-oncogene product, are thought to be determinant in the pathological processes of various malignancies. To investigate the possible role of HGF/SF in the progression of development of astrocytic tumors, we examined the expression of c-Met in these tumors. Immunohistochemistry using the streptavidin-biotin peroxidase complex method and immunofluorescence double staining with anti-c-Met polyclonal and anti-glial fibrillary acidic protein monoclonal antibodies were performed. Positive c-Met expression was detected in 31 of the 42 astrocytic tumors and some of the control cases analyzed. c-Met-positive cells showed morphological characteristics of astrocytes. Especially in the cases of high-grade tumors, c-Met positivity was abundant in cells in both vascular-rich and peripheral regions of the tumors but not in the cells with distinctly malignant features. Immunofluorescence double staining revealed that the c-Met-positive cells were in part of astrocytic origin. We suggest that c-Met-positive cells are affected by some factors in the lesions where the pathological processes are in a state of development. Our studies indicated that c-Met expression might take part in glioma invasion but not in the development of malignancy.

Astrocytes↗
PubMed1998

Acoustic reflex threshold and loudness in patients with unilateral hearing losses.

The relationship between the acoustic reflex threshold (ART) and loudness was examined in patients with unilateral hearing losses and subjects with simulated hearing losses using a masking method. Significant differences in the ART between the two ears of patients with unilateral hearing losses were correlated with differences in loudness at the level of the ART with differences in loudness determined by the alternate binaural loudness balance test. A similar relationship of ART and the sensation of loudness was also observed in ears with simulated hearing losses. The results obtained in the present study suggest a positive relationship between the ART and loudness, and provide some support for the assumption that a common neuronal information pathway plays an important role both in producing the loudness and eliciting the acoustic reflex.

Adolescent↗