Biomedical subjects

T Hatayama

Publications and source records attributed to T Hatayama.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Alleviation of sadness by pleasant imagery: analyses of subjective and physiological responses].

This study examined whether elicitation of joy or relaxation would reduce intensity of formerly induced sadness by using imagery tasks. Participants (N = 10) imaged a series of four sad scenes successively in the preliminary experiment. Dependent variables were subjective emotional ratings, heart rate, and facial electromyography of the corrugator and the zygomatic muscles. The result indicated that the sadness-imageries increased heart rate, corrugator activity, and zygomatic activity, as well as sad feeling. The procedure of the main experiment (N = 19) was almost the same as that of the preliminary experiment except that the sadness-imageries were followed by one of the 3 emotional imageries, that is, relaxation, neutrality, and joy. The result indicated that the relaxation-imagery marginally significantly decreased the heart rate that had been increased by the sadness-imageries. The joy-imagery reduced sad feeling but increased the zygomatic activity more than the relaxation-imagery. No effect was found on the heart rate. These results suggested that positive emotions alleviate sadness, and that joy and relaxation alleviate different aspects of sadness.

Adult↗

PubMed2000

[Electrophysiological mapping of the trigeminal nerve root during microvascular decompression for trigeminal neuralgia].

A method for intraoperative electrophysiological mapping of the intracranial root of the trigeminal nerve was studied in five patients with trigeminal neuralgia. During surgery, the trigeminal nerve root was stimulated centrally with a bipolar electrode, and antidromic responses were recorded peripherally from three branches of the trigeminal nerve in the face. In all patients, the fibers of the individual subdivisions of the trigeminal nerve root were successfully localized based on the peripheral sites of antidromic response. This neural mapping was used during microvascular decompression in four patients and during a rhizotomy procedure in one patient. As a result of mapping, the fibers of the trigeminal division subserving the pain were clearly confirmed to be compressed by the artery in all four patients who were undergoing microvascular decompression. Likewise, the antidromic responses precisely identified the first division of the trigeminal nerve, which should be preserved to avoid postoperative corneal ulcers in patients undergoing rhizotomy. Based on these findings, it was concluded that this technique enables surgeons to precisely identify which fibers of the trigeminal nerve root should be decompressed or divided during surgery for trigeminal neuralgia.

Aged↗

PubMed2000

Changes in cerebral blood flow after carotid endarterectomy.

We evaluated changes in cerebral blood flow (CBF) after carotid endarterectomy (CEA) in patients with internal carotid (ICA) stenosis. We studied 46 patients with ICA stenosis who underwent CEA. The mean age of the patients was 63 years, and their mean ICA stenosis was 73%. CBF in the middle cerebral artery territory was measured with xenon-enhanced CT tomography (Xe-CT) before and 3 weeks after CEA. In addition, cerebrovascular reactivity (CVR) was measured after intravenous administration of acetazolamide (ACZ) in 16 patients. There was no significant relationship between the degree of stenosis and CBF. Ten patients had decreased CBF before CEA, and CBF improved in nine of these after CEA. The CVR in 6 of 7 patients with impaired CVR before CEA improved to varying degrees after CEA. The CBF in patients with ICA stenosis varied according to the degree of collateral circulation. In conclusion, CEA can increase CBF and improve CVR in patients with low CBF or low CVR by restoring blood flow through the ICA.

Carotid Artery, Internal↗

PubMed1999

Differential temperature dependency of chemical stressors in HSF1-mediated stress response in mammalian cells.

Expression of stress proteins is generally induced by a variety of stressors. To gain a better understanding of the sensing and induction mechanisms of stress responses, we studied the effects of culture temperature on responses to various stressors, since the induction of hsp70 in mammalian cells by heat shock is somehow modulated by culture temperature. Hsp70 was not induced by treatment with sodium arsenite, azetidine-2-carboxylic acid, or zinc sulfate at the level of heat shock factor (HSF) 1 activation in cells incubated at low temperature, although these treatments induced hsp70 in cells incubated at 37 degrees C. The repression of sodium arsenite or zinc sulfate-induced HSF1 activation by low temperature was not simply due to the inhibition of protein synthesis. On the other hand, heat shock and iodoacetamide induced HSF 1 activation in cells incubated at either temperature. Thus, there seem to be two kinds of stressors that induce HSF1 activation independently of or dependent on culture temperature. Furthermore, the reduction of glutathione level seemed to be essential for HSF1 activation by chemical stressors.

Animals↗

PubMed1999

Genomic cloning and promoter analysis of the mouse 105-kDa heat shock protein (HSP105) gene.

The 105-kDa heat shock protein (HSP105) is a member of the high-molecular-mass heat shock protein family. We have isolated and characterized the mouse HSP105 gene including about 1.2 kb of the 5'-flanking region. The mouse HSP105 gene spans about 22 kb, consisting of 18 exons separated by 17 introns. Southern blotting analysis revealed the existence of a single copy of HSP105. Primer extension analysis revealed that the transcription initiation site was located 165 bp upstream of the ATG translation initiation codon. The 5'-promoter region of the HSP105 gene contained a TATA box, a CAAT box, an inverted CAAT box, and two GC boxes. Two heat shock element (HSE) sequences were found as four nGAAn repeats at nt -64 and nt -128. Promoter analysis using deletion derivatives revealed that a minimal region which contained the two consensus HSE sequences was active in response to heat shock and also for constitutive expression of the gene.

Alternative Splicing↗

PubMed1999

Molecular cloning, expression and localization of human 105 kDa heat shock protein, hsp105.

We have shown that the 105 kDa heat shock protein (hsp105alpha) and hsp105beta (42 degreesC-specific heat shock protein) constitute high molecular mass (HMM) heat shock proteins (HSPs) in mouse cells. However, since HMM HSPs have not been identified in human cells, we screened a cDNA library constructed with poly(A)+ RNA derived from heat-shocked human HeLa cells using mouse hsp105alpha cDNA. Two full-length cDNA clones were obtained: the pBH105-1 insert encoded an 858-amino-acid protein, and the pBH105-2 insert encoded an 814-amino-acid protein which lacked 44 amino acids from pBH105-1. The deduced amino acid sequences of pBH105-1 and pBH105-2 inserts were highly homologous to mouse hsp105alpha (96%) and hamster hsp110 (92%), and to mouse hsp105beta (93%), respectively. The transcript of pBH105-1 was induced by various stresses in HeLa cells, but the transcript of pBH105-2 was only induced during heat shock at 42 degreesC. These results indicated that pBH105-1 and pBH105-2 encoded human hsp105alpha and hsp105beta, respectively. Furthermore, a rabbit antibody was raised against recombinant human hsp105alpha, and immunofluorescence study also confirmed that hsp105 was present in the cytoplasm but was not found in the nucleoli of mammalian cells under both nonstressed and stressed conditions.

Alternative Splicing↗

PubMed1999

A case of endolymphatic sac tumor with long-term survival.

A 72-year-old man developed left facial palsy at age 14 and left-sided hearing loss at age 20. At the age of 59, he presented with gait disturbance, and a large left cerebellopontine angle tumor was detected, which had markedly destroyed the pyramidal bone. The tumor was subtotally resected, but he required two more operations at the ages of 64 and 69 because of tumor regrowth. At the present time, recurrent tumor has destroyed the occipital bone and is invading the scalp. However, even though he has several cranial nerve palsies and cerebellar ataxia, he remains in stable condition and demonstrates long-term survival. The patient's surgical specimens revealed a papillary adenoma, which was recently thought to be of endolymphatic sac origin, although the origin of this kind of tumor, whether arising from the middle ear or from the endolymphatic sac, has not been established with certainty so far. In this paper, we provide further evidence that this tumor originates from the endolymphatic sac, based on anatomical, histopathological, and embryological evidence.

Adenoma↗

PubMed1999

Effect of compression on the cochlear nerve: a short- and long-term electrophysiological and histological study.

The short- and long-term effects of static compression of the cochlear nerve were studied in dogs. The nerve was exposed in the cerebellopontine angle and a modified aneurysm clip was applied to reduce the diameter of the nerve trunk to 50%, 40%, 30% or 20% of normal (designated respectively as 50%, 60%, 70%, and 80% compression). Brainstem auditory evoked potentials (BAEPs) were monitored intraoperatively and post-operatively. The animals were sacrificed between 5 and 119 days after nerve compression and temporal bones were examined histologically. In the 50% compression group, all peaks except peak I disappeared immediately after nerve compression. After release of the clip, however, peak II and subsequent components recovered and prolonged interpeak latency (IPL) between peaks I and IV normalized within 7 days. In the 60% compression group, recovery was incomplete for as long as 49 days after compression. Significant histological changes were not always reflected in the electrophysiological recordings, as shown by the finding of multiple cavitations at the compressed portion of the cochlear nerve in cases in which conduction block of cochlear nerve impulses was reversible. In the 70% compression group, peak IV did not reappear for more than 1 week, and histological examination revealed severe damage to all cochlear nerve fibers except those from the apical turn, which lie in the center of the cochlear nerve trunk. Severe injury occurred to the cochlear nerve fibers that are situated more superficially in the nerve, which are tonotopically responsible for the perception of high-frequency sound and the generation of BAEPs. This means that the BAEP changes due to cochlear nerve compression would be detectable by BAEP monitoring, although changes in the apical region of the cochlea are not fully detectable by BAEP monitoring. In the 80% compression group, all peaks except peak I were lost permanently and the amplitude of peak I, which had been preserved in the acute phase, gradually decreased. Reversibility of impaired cochlear nerve impulse conduction was related to the severity of compression, and at some level of compression between 70% and 80% the nerve fibers generating BAEPs permanently lost the ability to conduct electrical impulses proximal to the site of compression. In the 70% and 80% compression groups, the amplitude of peak I gradually decreased over the first 30 days after compression and did not change significantly thereafter. Histologically, the branches of the internal auditory artery were resilient to compression, although they are easily avulsed due to stretch force. Furthermore, retrograde degeneration of cochlear neurons triggered by compression at the cisternal portion of the cochlear nerve was apparent. Such slowly progressive degeneration of nerve fibers may play a part in development of the delayed postoperative hearing disturbance.

Animals↗

PubMed1999

Comparison of transcranial Doppler investigation of aneurysmal vasospasm with digital subtraction angiographic and clinical findings.

OBJECTIVE: Transcranial Doppler (TCD) findings for evaluation of the severity of vasospasm (VSP) in patients with ruptured aneurysmal subarachnoid hemorrhage are controversial. To clarify these TCD findings, intra-arterial digital subtraction angiography was used to simultaneously investigate the angiographic features of cerebral vessels and the cerebral circulation time (CCT). METHODS: Fifty patients with ruptured aneurysms, for whom computed tomographic scans indicated Fisher Grade III subarachnoid hemorrhage, were investigated. Aneurysmal neck clipping was performed in the acute stage. The mean flow velocity (MFV) at the M1 segment was measured using TCD ultrasonography. Intra-arterial digital subtraction angiography was used to simultaneously investigate angiographic features and CCTs on Days 7 to 13. The CCT was defined as the time difference between the two peaks in optical density curves recorded at the carotid artery (C3-C4 portion) and the ascending vein, after contrast material injection. Angiographic VSP was categorized using a modification of the Fisher classification. RESULTS: Angiograms for 9, 25, and 16 patients showed no, slight to moderate, and severe VSP, respectively. The MFVs of the patients with no, slight to moderate, and severe VSP were 70, 115, and 116 cm/s, respectively. No significant difference among the three groups could be observed. The mean CCTs of the patients with no, slight to moderate, and severe VSP were 4.1, 4.6, and 6.5 seconds, respectively. The CCTs of the patients with severe VSP differed significantly from those of the patients with no or slight to moderate VSP. The patients with severe VSP were divided into two groups. One group included eight patients with severe VSP at proximal sites (the internal carotid artery to the M1 segment), and the other included eight patients with severe VSP extending to the M2 segment and more peripheral sites. The mean CCT of the former group (5.3 s) was significantly different from that of the latter (7.5 s), and the MFV of the former group (128 cm/s) was significantly higher than that of the latter (81 cm/s). The clinical outcomes for the latter patients were more serious than those for the former patients. CONCLUSION: This study suggests that the MFV at the M1 segment is inadequate for estimation of the severity of VSP extending to vessels more peripheral than the M1 segment. Furthermore, severe VSP extending to more peripheral sites can produce more serious ischemic insults, compared with that localized to basal vessels. Patients with negative TCD results and clinical features suggesting the development of VSP should undergo quantitative investigation of cerebral circulatory parameters, such as the CCT, using intra-arterial digital subtraction angiography.

Aneurysm, Ruptured↗

PubMed1999

Persistent primitive hypoglossal artery associated with cerebral aneurysm and cervical internal carotid artery stenosis--case report.

A 71-year-old female had vertigo attacks once or twice a day secondary to vertebrobasilar insufficiency. Left carotid angiography revealed persistent primitive hypoglossal artery (PPHA) associated with a large internal carotid artery (ICA) aneurysm and severe stenosis of the ICA. The bilateral vertebral arteries were hypoplastic. The basilar artery was opacified via the PPHA but not via vertebral arteries. Clipping of the aneurysm was performed first because the risk of rupture of the aneurysm was not negligible. One month after clipping, carotid endarterectomy using a T-shaped shunt system was successfully performed. The postoperative course was uneventful and the vertebrobasilar ischemic attacks did not recur. Left carotid angiography demonstrated complete obliteration of the aneurysm and disappearance of the carotid artery stenosis. Low ICA flow (70 ml/min) and low stump pressure of the PPHA (25 mmHg) strongly suggested low perfusion of the posterior circulation. Carotid endarterectomy may be essential for augmentation of the posterior circulation in patients with PPHA associated with ICA stenosis.

Aged↗

PubMed1999

[Intraoperative electrophysiological monitoring for functional preservation of the cauda equina during lumbosacral surgery].

Adequate electrophysiological techniques to monitor function of the cauda equina have been proposed for surgery in patients with lumbosacral lipoma or myeloschisis. Motor fibers were identified by electrical stimulation in the operating field with bipolar rectangular impulses of 200 mu sec duration at 2 Hz under 5 mA and compound muscle action potentials (CMAPs) recorded from the leg and anal muscles. By recording CMAPs from the tibialis anterior, the biceps femoris, the gastrocnemius, and the external anal sphincter muscles, all of the roots from the fourth lumbar to the fourth sacral segment were continuously monitored. To spare recording channels, recordings were obtained from the right versus the left side. In our institute, 5 patients have undergone lumbosacral surgery while using this monitoring system, and the results indicated that there was no postoperative neurological exacerbation in any of the cases. According to a combination of the CMAPs produced by stimulation, the segment of the stimulated motor root could be identified electrophysiologically. Monitoring of somatosensory evoked potentials was not performed because this would have required too much time and would have prolonged surgery. However, some sensory fibers, which appeared to be posterior roots of the cauda equina on intraoperative inspection, could be identified indirectly with CMAPs recording because of current spreading from the stimulation to motor fibers.

Action Potentials↗

PubMed1998

Association of HSP105 with HSC70 in high molecular mass complexes in mouse FM3A cells.

The 105-kDa stress proteins HSP105alpha and HSP105beta belong to a high molecular mass heat shock protein family which has been found in organisms from yeast to mammals. Here we demonstrated the interaction of HSP105 with HSP70 family proteins in mouse FM3A cells. The association of HSP105 with HSC70 was shown by immunoprecipitation using anti-HSP105 antibody. Furthermore, when cell extracts or partially purified HSP105 fractions from nonstressed or heat-shocked cells were analyzed by size exclusion chromatography, density gradient centrifugation or cross-linking, HSP105 was detected as HSP105/HSC70 complexes with molecular masses of approximately 300-500-kDa, 160-kDa or 200-kDa, respectively. Since the 160-200-kDa complexes must be HSP105/HSC70 heterodimers, the 300-500-kDa complexes seemed to consist of HSP105/HSC70 heterotetramers possibly with other proteins. Our finding that HSP105 is complexed with HSC70 suggests that HSP105 may function cooperatively with HSC70, that HSP105 regulates the function of HSC70 or that HSC70 reversibly regulates the function of HSP105 in cells under both nonstressed and stressed conditions.

Adenosine Triphosphate↗

PubMed1998

Correlation between latency and amplitude of peak V in the brainstem auditory evoked potentials: intraoperative recordings in microvascular decompression operations.

Intraoperative prolongation of the latency and decrement of the amplitude of peak V of brainstem auditory evoked potentials (BAEP) were studied in 38 microvascular decompression operations in which prolongation of the latency of peak V exceeded 1.0 msec. Postoperative hearing tests of all patients were compared with their preoperative hearing tests. Postoperative hearing loss was unrelated to the maximum prolongation of latency, but the amplitude decreased to lower values in patients with postoperative hearing loss compared to patients whose postoperative hearing was unchanged (P < 0.05). Twelve (32%) of 38 patients whose latency of peak V was prolonged more than 1.0 msec and 11 (61%) of 18 patients whose amplitude of peak V decreased more than 40% during the operations had decreased hearing postoperatively. In all patients, a prolongation of the latency of peak V was always accompanied by a decrease in the amplitude of peak V. The decrement of the amplitude was greater in the patients with decreased postoperative hearing thresholds than in the patients with unchanged postoperative hearing thresholds. The results of this study indicate that it would be valuable to monitor changes in the amplitude of peak V of BAEP in addition to monitoring the latency of peak V during operations where the VIIIth cranial nerve is manipulated.

Adult↗

PubMed1998

Characteristic expression of 105-kDa heat shock protein (HSP105) in various tissues of nonstressed and heat-stressed rats.

Although the induction of heat shock proteins (HSP) has been studied extensively in cultured cells, comparatively few studies have examined their expression in vivo. In this report, we investigated the expression and the state of 105-kDa heat shock protein (HSP105) in various tissues of rats, and found that two isoforms of HSP105 (HSP105-a and HSP105-b) were both moderately expressed in adrenal, spleen, liver and heart, and both increased markedly after heat shock. However, in brain HSP105-a was characteristically highly expressed over HSP105-b, but neither increased after heat shock. In addition, a 100-kDa protein (p100), a possible testis-specific HSP105 homologue was found in testis. When the effects of adrenaline and its antagonists on the heat-inducibility of HSP105 were examined, the induction of HSP105 in adrenal gland seemed to be negatively regulated through the alpha-adrenergic receptor. Furthermore, HSP105 was found to be associated with HSC70/HSP70, and to exist as high molecular mass complexes of 300-800-kDa and of 300-500-kDa in various tissues of nonstressed and heat-stressed rats, respectively. The molecular interaction between HSP105 and HSC70 suggests the possibility that HSP105 functions with HSC70 cooperatively in various tissues of rats.

Adrenergic Agents↗

PubMed1998

Rerupture of coil-embolized aneurysm during long-term observation. Case report.

The authors describe the histopathological findings in a case involving rerupture of a recanalized aneurysm of the internal carotid artery 8 months after partial (95%) embolization with interlocking detachable coils. The aneurysm was filled with poorly organized thrombus, and its orifice was devoid of endothelial cells. It appears likely that a long period of observation may be required to confirm the complete thrombotic organization of coil-embolized aneurysms. This indicates that caution is needed because rupture may follow recanalization of the aneurysm.

Aged↗

PubMed1998

[Macroscopic and pathohistological investigation of endarterial plaque after intraoperative balloon dilatation of the carotid artery during carotid endarterectomy].

Twelve patients associated with stenosis of the extracranial carotid artery underwent intraluminal balloon dilatation during carotid endarterectomy (CEA). There were 11 men and 1 woman, and age ranged from 56 to 73 years old. The rate of stenosis, shown by angiography, in each patient was from 60 to 85% in width. After securing carotid blood flow by a T-shaped shunt tube, a balloon catheter was inserted from the exposed common carotid artery into the internal carotid artery. The balloon was inflated three or four times with 2.5-3.5 atm. for 30-40 seconds. Immediately after balloon dilatation, endoscopic investigation was performed (Wolf; hard type endoscope, 2.7 mm diameter). Then CEA was performed using the usual procedure. The removed endarterial plaque was investigated pathohistologically. In macroscopic and endoscopic findings, there were 6 patients with mural thrombosis, 4 patients with laceration of the intima, and one patient with outflow of atheroma from the intima. Only 3 patients had increase in lumen after balloon dilatation. In pathohistological appearance, all patients had a moderate degree of fibrosis, calcification, and atheroma in the cross section of the plaque. Ten patients had intramural hemorrhage. Three typical patients were revealed by the use of angiographical, ultrasonographical, endoscopic, and pathohistological presentation. Case 10 showed laceration of the intima by balloon dilatation, and had moderate increase in lumen size macroscopically and endoscopically. There were moderate cases of fibrosis, calcification, atheroma, and intramural hemorrhage. Dilatation of the lumen seemed to be accomplished by a decrease in thickness of the atheroma and intramural hemorrhage. Case 8 demonstrated an increase in lumen size, but also laceration of the intima and outflow of atheroma from the arterial wall. There were much atheroma and large intramural hemorrhage in the intima, which might become a source of enbolism. Case 7 revealed no laceration of the intima and no increase in lumen size. Preoperative ultrasonography showed hyperechoic finding and postoperative pathohistological findings showed severe fibrosis and calcification, which were thought to have interrupted balloon dilatation. There have been small numbers of reports about pathohistological presentation after percutaneous transluminal angioplasty (PTA), because it is very difficult to take a specimen after PTA. In this report we were able to present the necessity of preoperative investigations by angiography, ultrasonography, and 3D-CT.

Aged↗

PubMed1997

Free radical-mediated effects on skeletal muscle protein in rats treated with Fe-nitrilotriacetate.

Changes in protein conformation and proteolysis in skeletal muscle of rats were studied by the induction of oxidative stress induced in vivo by ferric nitrilotriacetate (FeNTA) treatment. Useful indices of protein modification, including both protein carbonyl content and fluorescence intensity of protein hydrolysate in skeletal muscle, were increased 3 h following FeNTA treatment to rats. Western blot using anti-dinitrophenyl antibody showed oxidative modification of actin and myosin in myofibril by FeNTA. These results demonstrated that muscle proteins were modified after radical attack induced by an iron overload. Furthermore, oxidative stress induced by iron overloading resulted in enhanced degradation of myofibrillar proteins. It is suggested that muscle proteins which have been modified by oxidative stress undergo rapid removal.

Animals↗

PubMed1997

A possibility for new evaluating method of cytotoxicity by using heat shock protein assay.

To determine whether heat shock proteins can be utilized as a biomarker for cytotoxicity of dental materials the induction of synthesis of heat shock proteins by mercuric chloride was examined. To analyse the synthesis of heat shock proteins, HeLa cells were labelled with [35S] methionine, and the labelled proteins were separated by SDS-PAGE and autoradiographed. Incubation of the cells in a medium containing 1.25 to 40 microM mercuric chloride markedly increased the synthesis of HSP70. At 20 or 40 microM mercuric chloride in medium, HeLa cells synthesized HSP70 at 2 h after exposure, maximally at 4-7 h, and gradually diminished thereafter. Examination of the cytotoxicity of mercuric chloride by the conventional neutral red uptake assay revealed a reduction of uptake of the dye in the presence of mercuric chloride at 40 microM and above. These findings suggest that the induction of synthesis of HSP70 is one of the most sensitive cellular responses caused by mercury ion, and the heat shock protein assay can be utilized for evaluation of the cytotoxicity of dental materials.

Journal Article↗