PubMed Health⌕ Search

Biomedical subjects

T Hatayama

Publications and source records attributed to T Hatayama.

At least 55 records · Page 3Linked to original sources
PubMed1997

Reduced induction of HSP70 in PC12 cells during neuronal differentiation.

Rat pheochromocytoma PC12 cells differentiate into nonreplicating neuronal cells with neurite extensions in response to nerve growth factor (NGF). To gain better understanding of the regulation of stress responses in neuronal cells, we examined the induction of HSP70, HSP70 mRNA, and heat shock factor 1 (HSF1) DNA-binding activity following treatment by heat shock or with sodium arsenite or amino acid analogue in PC12 cells treated with or without NGF. The induction of HSP70 and HSP70 mRNA following these stresses was diminished in the differentiated PC12 cells compared to the undifferentiated cells, whereas the HSF1 DNA-binding activity was enhanced in the differentiated PC12 cells. This phenomenon was characteristic of the differentiated neuronal cells rather than growth-arrested cells. Thus, neuronal cells appear to show an altered stress response depending on their differentiation state, and the diminished HSP70 expression in the differentiated neuronal cells may explain the sensitivity of neuronal cells to pathophysiological stressors.

Animals↗
PubMed1997

Characteristic expression of high molecular mass heat shock protein HSP105 during mouse embryo development.

Expression of 105 k-Da heat shock protein (HSP105) during mouse embryo development was investigated. Although HSP105 was detected scarcely in mouse embryos at gestational day (GD) 8, its level of HSP105 increased markedly in the embryos from GD 9 to 11, and then decreased gradually by GD 14. In contrast, 70 k-Da heat shock cognate protein (HSC70) was detected at constantly high levels in embryo from GD 8 to 17 (before birth). The transient increase in level of HSP105 was observed in most embryonic tissues. Since the levels of HSP105 mRNA was detected at constantly high levels in the embryos between GD 8 and 12, the increased expression of HSP105 at GD 9 to 11 seemed to be regulated at posttranscriptional level. Immunohistochemically, HSP105 as well as HSC70 were localized in the cytoplasm and the nuclei of cells in various mouse embryonic tissues. After treatment of tissue sections with proteinase K, HSP105 but not HSC70 was also found to be localized in condensed cells and condensed bodies which showed the typical characteristics of apoptotic cells and apoptotic bodies at the interdigital regions of limbs. These findings suggest that HSP105 plays important roles during mouse embryo development.

Animals↗
PubMed1997

Effects of hyperosmotic NaCl and glycerol stress on stress response of human HeLa cells.

The maintenance of intracellular osmotic pressure is of fundamental importance for cell survival. Since osmoregulatory processes are important to all living organisms, large fluctuations in environmental osmolarity may elicit or modulate stress responses. We examined whether hyperosmotic stress induced or modulated stress responses in human HeLa cells. When HeLa cells were incubated in medium supplemented with 50-150 mM NaCl or 0.2-1.0 M glycerol for 3-27 h, the stress response, analyzed at the levels of HSP70 synthesis, HSP70 mRNA accumulation, and heat shock transcription factor (HSF) activation, was not induced by either hyperosmotic stress. In hyperosmotic 150 mM NaCl or 1.0 M glycerol medium, the stress response to heat shock was inhibited at the levels of HSF activation, HSP70 mRNA accumulation, and HSP70 synthesis. In vitro activation of HSF showed that inhibition of this activation by hyperosmotic NaCl or glycerol stress was not irreversible. Furthermore, addition of the physiological osmolyte betaine to medium reversed the inhibition of heat-induced HSP70 synthesis under hyperosmotic NaCl stress but not under hyperosmotic glycerol stress. The effect of betaine against hyperosmotic NaCl stress was observed mainly at the translation level, and betaine seemed to enable cells to translate HSP70 mRNA specifically under heat shock conditions by restoring protein synthetic ability.

Betaine↗
PubMed1997

[A case of isolated ACTH deficiency accompanied by generalized painful muscle cramp].

We report a patient who had generalized painful muscle cramps associated with isolated ACTH deficiency. A 68-year-old woman was hospitalized because of painful muscle cramps present for one year. Neurological examination revealed no abnormalities except for generalized painful muscle cramps. Serum electrolyte and CPK levels were normal. Serum ACTH and cortisol levels as well as urine 17-OHCS were low. An ACTH loading test employing insulin, TRH and LH-RH indicated isolated ACTH deficiency. Just after the muscle cramp, EMG revealed a low amplitude in the biceps muscle. Colon biopsy showed mild fibrosis and inflammatory cell infiltration in the lamina propria. Her muscle cramps improved markedly after two weeks of hydrocortisone replacement therapy and resolved after three weeks, suggesting that this symptom was closely related to isolated ACTH deficiency. Our case suggests that isolated ACTH deficiency may present with very similar clinical symptoms to Satoyoshi disease.

Adrenocorticotropic Hormone↗
PubMed1997

[A simplified method to monitor oculomotor nerve function in midbrain surgery: recordings of compound muscle action potentials by percutaneous superior orbital electrode].

We report a simple and easily-applicable method to intraoperatively monitor the oculomotor nerve and oculomotor nucleus in the brainstem. A needle electrode is inserted into the space just beneath the superior root of the orbit. With this superior orbital electrode, evoked compound muscle action potentials from the superior rectus and the levator palpebrae superioris muscles were recorded. The nuclei for these two muscles are located caudally in the midline of the midbrain. The responses from the superior orbital electrode, therefore, give the surgeons useful intraoperative guidance during surgery for pineal region tumors and midbrain gliomas.

Action Potentials↗
PubMed1996

[Establishment of the criteria to evaluate intraoperative changes of brainstem auditory evoked potentials during microvascular decompression and acoustic neurinoma excision].

Although monitoring of brainstem auditory evoked potentials (BAEP) is helpful to preserve hearing during operations in the cerebellopontine angle such as microvascular decompression and excision of an acoustic neurinoma, criteria for what and when changes in BAEP should be communicated to the surgeon have not been well established. An exhaustive review was, therefore, conducted of the English and Japanese literature on this topic. Analysis of the results of this literature review led to the conclusion that during a microvascular decompression procedure, the surgeon should be warned as soon as progressive prolongation of the latency of wave V of the BAEP exceeds 1.5 msec. It is reasonable to apply stricter criteria in acoustic neurinoma excision; prolongation of wave V latency even less than 0.5 msec should be regarded as the warning sign to the surgeon who is trying to preserve hearing. Whenever BAEP monitoring is performed, it is crucial that changes in the BAEP are evaluated in light of the particular surgical procedure in progress and that the person who evaluates these changes is well versed in the conduct of the surgical procedure.

Cochlear Nerve↗
PubMed1996

[Retrovesical leiomyoma: a case report].

We report a case of retrovesical leiomyoma in a 53-year-old woman. In September, 1994, she visited our clinic with the chief complaint of urinary retention. Drip infusion pyelography (DIP), computed tomographic (CT) scan, and magnetic resonance imaging (MRI) revealed a large tumor behind the urinary bladder. Simple tumor excision was performed. The tumor, 7 x 7 x 6 cm in size and 250 g in weight, was histologically diagnosed as leiomyoma. This is the 18th case of retrovesical leiomyoma reported in the literature in Japan.

Aged↗
PubMed1995

Cloning and expression of murine high molecular mass heat shock proteins, HSP105.

We have shown that the 105-kDa heat shock protein (HSP105) and the 42 degrees C-specific heat shock protein (42 degrees C-HSP) constitute high molecular mass heat shock proteins. To elucidate the structure of these heat shock proteins, we have screened a cDNA library constructed with poly(A)+ RNA derived from mouse FM3A cells preheated at 42 degrees C for 2 h using an antibody against murine HSP105. Two full-length cDNA clones were obtained: the pB105-1 insert encoded an 858-amino acid protein, and the pB105-2 insert encoded an 814-amino acid protein and lacked 44 amino acids found in pB105-1. The two clones contained the amino acid sequence found in the 17-kDa polypeptide fragments from HSP105 and 42 degrees C-HSP by lysylendopeptidase digestion. In vitro translation products of the RNA transcripts from pB105-1 and pB105-2 migrated to the same positions of HSP105 and 42 degrees C-HSP, respectively, on SDS-polyacrylamide gel electrophoresis. Northern blot analysis showed that the transcript was approximately 4 kilobases in murine FM3A cells and was strongly induced by heat shock and by treatment with arsenite or an amino acid analog. By reverse transcription-polymerase chain reaction analysis using primers by which deletion of 132 nucleotides in pB105-2 could be detected, the polymerase chain reaction product corresponding to pB105-2 was increased only after heat shock at 42 degrees C, whereas the product corresponding to pB105-1 was induced by heat shock at either 42 or 45 degrees C and also by other stresses. Thus, the cDNA clones pB105-1 and pB105-2 encode HSP105 and 42 degrees C-HSP, respectively, and HSP105 and 42 degrees C-HSP (a short form of HSP105) are suggested to be produced by alternative splicing. Here, HSP105 and 42 degrees C-HSP are renamed HSP105 alpha and HSP105 beta, respectively. A protein sequence homology search revealed that HSP105 shares 54, 34, and 25% amino acid identity with human HSP70RY, the sea urchin egg receptor for sperm, and murine inducible HSP70, respectively. Furthermore, by Northern blot analysis, HSP105 mRNA was revealed to be present in most murine tissues and to be highly expressed in the brain.

Amino Acid Sequence↗
PubMed1995

Inhibition mechanism of HSP70 induction in murine FM3A cells maintained at low culture temperature.

We have shown previously that induction of HSP70 synthesis in murine FM3A and its mutant ts85 cells by heat shock is somehow modulated by culture temperature. In this study, we further examined activation of heat shock transcription factor (HSF) and induction kinetics of HSP70 synthesis and HSP70 mRNA in FM3A and ts85 cells maintained at 37 degrees C (37 degrees C-cells) and 33 degrees C (33 degrees C-cells). Upon exposure to heat shock, HSF was activated to a high level in 37 degrees C-FM3A cells, whereas HSF was activated only to a low level in the 33 degrees C-cells. The induction of HSP70 mRNA and HSP70 synthesis occurred successively in the 37 degrees C-cells but not in the 33 degrees C-cells. On the other hand, in both 37 and 33 degrees C-ts85 cells, activation of HSF, induction of HSP70 mRNA, and HSP70 synthesis occurred successively. Characteristically, protein synthesis in both 33 degrees C-FM3A and ts85 cells was significantly lower than in the respective 37 degrees C-cells, but constitutive HSP73 levels were similar among both the 37 and 33 degrees C-cells. Furthermore, inhibition of protein synthesis of FM3A cells did not influence the activation of HSF, but accelerated inactivation of the activated HSF. We discuss the possible inhibition mechanisms of activation of HSF in 33 degrees C-FM3A cells, regarding the function of HSP70 in both protein synthesis and repression of HSF.

Animals↗
PubMed1995

Thermosensitization of murine FM3A cells by transient incubation at low culture temperatures.

We show that when murine FM3A cells maintained at 37 degrees C were incubated at low culture temperatures between 24 degrees and 33 degrees C for 12-24 h, they became thermosensitive as compared to those incubated at 37 degrees C. The synthesis and accumulation of inducible HSP70 and constitutive HSC70 by heat shock decreased in cells incubated at 33 degrees C, whereas no such decreases were found in cells incubated at 37 degrees C. The accumulation of HSP105 because of heat shock also decreased in cells incubated at 33 degrees C. The decreased inducibility of HSP70, HSC70, and HSP105 by heat shock may in part be responsible for the increase seen in the thermosensitivity of the cells. Furthermore, the cellular concentration of HSP105 decreased in cells incubated at 33 degrees C but not in those incubated at 37 degrees C, whereas the concentration of HSC70 did not change at all in cells incubated at either temperature. The cellular content of HSP105, but not of HSC70, therefore may be a good indicator of the thermoresistant state of cells.

Animals↗
PubMed1995

[Intraoperative monitoring of the lower cranial nerves during skull base surgery: evoked electromyographic technique].

Functional preservation of the lower cranial nerves is an important issue in the surgery of the skull base to avoid postoperative serious complications such as aspiration pneumonia and respiratory disorders. We presented our experience of intraoperative monitoring of the lower cranial nerves during skull base surgery. The evoked electromyographic (EMG) activities were successfully recorded from the muscles innervated by the lower cranial nerves. These EMG recordings are helpful to guide the surgeon intraoperatively and to avoid careless severing of these nerves. Although the glossopharyngeal nerve that innervates only one small muscle in the pharynx (M. stylopharyngeus) cannot be monitored with the evoked EMG technique described in this paper, the position of this nerve can be deduced from the position of the vagus nerve.

Adult↗
PubMed1994

Characterization of high-molecular-mass heat shock proteins and 42 degrees C-specific heat shock proteins of murine cells.

There are two isoforms of high-molecular-mass heat shock protein (HMM-HSP), hsp105A and hsp105B, in murine FM3A cells. To characterize the HMM-HSPs, we here purified hsp105A and hsp105B, as well as 42 degrees C-specific HSPs that are specifically induced by continuous heating at 42 degrees C, from the cytoplasmic extracts of the FM3A cells heat-shocked at 42 degrees C for 8 h. Digestion of the hsp105A, hsp105B, and 42 degrees C-specific HSPs with lysyl endopeptidase generated 17,000-Da polypeptide fragments in common, and the N-terminal amino acid sequences of the fragments revealed a homology with those of the adenosine binding domain of hsp70 family proteins and actin. Thus, the two isoforms of hsp105 and the 42 degrees C-specific HSPs seemed to be very similar proteins having a ATP binding domain in common, and these HSPs may constitute a HMM-HSP family in murine cells.

Amino Acid Sequence↗
PubMed1994

Cellular localization of high-molecular-mass heat shock proteins in murine cells.

We have previously prepared an antiserum raised against hsp105 of murine FM3A cells. The anti-hsp105 serum reacted to two isoforms of high-molecular-mass heat shock protein (HMM-HSP) having a molecular mass of 105,000 Da (hsp105A and hsp105B) in FM3A cells. While hsp105A and hsp105B were both synthesized and accumulated under non-stressed conditions, upon exposure to heat shock much more hsp105B was induced than hsp105A. When the cellular distribution of these hsp105s in murine 3T3 Swiss albino and C3H 10T1/2 cells was examined by immunofluorescence methods using the anti-hsp105 serum, the HMM-HSPs were localized in the cytoplasm and nuclei and were never found in the nucleoli of both 3T3 and C3H cells under non-stressed and stressed conditions.

3T3 Cells↗
PubMed1994

Primary pineal melanoma with long-term survival: case report.

A rare case of primary pineal melanoma is reported. The patient was a 53-year-old woman who complained of a severe headache. Computed tomography and magnetic resonance images revealed obstructive hydrocephalus caused by a mass lesion in the pineal region. A biopsy was performed through an occipital transtentorial approach. A black pigmented solitary tumor was seen without leptomeningeal dissemination. Histologic examination revealed melanoma. Chemotherapy consisting of dacarbazine, ACNU, vincristine, and interferon was used. Follow-up imaging studies showed dramatic reduction of the tumor without recurrence for 4 years. This report demonstrates that a solitary primary intracranial melanoma without leptomeningeal dissemination and with rare mitoses may yield a good result with chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

[Evaluation of Matas test by CBF studies, angiographic cross-filling and stump pressure in CEA patients].

Temporary and/or permanent occlusion of carotid artery is one of the most important strategy in the surgical treatment for cervical vascular and paraclinoid lesions. Cerebral ischemia produced by this procedure should be preoperatively grasped for the safety of the surgeries. Matas test has been widely applied to estimate the collateral blood flow at the main artery occlusion by observing only clinical features. In this study, we measured CBF and common carotid artery stump pressure (CCA stump P) in contrast to angiographic cross-filling in 43 carotid endarterectomy (CEA) patients to quantitatively evaluate Matas test. The patients were manually occluded the CCA on the affected side and clinically observed for at least 10 minutes. CCA stump P and cross-filling were evaluated in all patients and CBF measurements were carried out in the patients who clinically tolerated Matas test. CBF studies were performed by single photon emission CT with Xe-133 inhalation method and CBF values were obtained in the middle cerebral artery territory before and during Matas test. CCA stump P was measured during carotid angiography by manual occlusion of the proximal site of the CCA. Cross-filling was evaluated with the contralateral carotid angiography during the manual occlusion of the affected CCA. CBF changes in Matas test were classified into the following four patterns; bilateral mild decreases in CBF, unilateral severe decrease in CBF, unilateral mild decrease in CBF and no decrease in CBF. The frequency of bilateral mild decreases in CBF, unilateral severe decrease in CBF, unilateral mild decrease in CBF and no decrease in CBF were 8, 10, 14, 7 of 43 patients, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Ischemia↗
PubMed1994

[Near infrared spectrophotometric monitoring for cerebral ischemia during the occlusion of the internal carotid artery at CEA].

Near infrared spectrophotometry provides noninvasively real-time information on cerebral oxygenation and cerebral blood volume. Using this method of spectrophotometry we investigated the adequacy of collateral circulation during cross-clamping of the internal carotid artery in patients who underwent carotid endarterectomy. In 15 patients, oxy-hemoglobin, deoxyhemoglobin and total hemoglobin were monitored continuously by near infrared spectrophotometry at the ipsilateral frontal area on the operated side. Changes in these parameters following temporary cross-clamping of the internal carotid artery were evaluated. The stump pressure of the internal carotid artery was measured in every patient. Only the maximum decrease in oxy-hemoglobin during cross-clamping of the internal carotid artery correlated significantly with the stump pressure of the internal carotid artery. Changes in oxy-hemoglobin during cross-clamping of the internal carotid artery demonstrated three patterns; no change or minimally decreased (4 patients), decrease with recovery (4 patients), and decrease without recovery (7 patients). The stump pressure of the internal carotid artery in patients who had no recovery of their decreased oxy-Hb was significantly lower than that in any other pattern (p < 0.01, Mann-Whitney U analysis). Patients who experience decrease in oxy-Hb without recovery following cross-clamping of their internal carotid artery may have poor collateral circulation and therefore may develop cerebral ischemia.

Aged↗
PubMed1994

[Ruptured distal anterior cerebral artery aneurysms presenting with acute subdural hematoma: report of two cases].

Two cases of ruptured distal anterior cerebral-artery aneurysms presenting with acute subdural hematoma are reported. Case 1 was a 55-year-old male, who showed abrupt disturbance of consciousness. An emergency CT revealed acute subdural hematoma at the right parietal convexity and interhemispheric fissure with moderate midline shift. There was no evidence of subarachnoid hemorrhage. Right carotid angiography showed an aneurysm at the right distal anterior cerebral artery. An emergency external decompression was performed and the aneurysm was clipped successfully through the interhemispheric fissure. In the operative field, subarachnoid hemorrhage could not been seen, and the patient had uneventful recovery. Case 2 was a 66-year-old female, who complained of severe headache. She deteriorated rapidly and become comatous with development of anisocoria. An emergency CT revealed acute subdural hematoma on the bilateral parietal convexities and interhemispheric fissure with severe midline shift. There was no evidence of subarachnoid hemorrhage. Carotid angiography showed right distal anterior cerebral artery aneurysm. An emergency external decompression was performed, then the aneurysm was clipped successfully. She recovered with disorientation and hemiparesis. Ruptured distal anterior cerebral artery aneurysms presenting with acute subdural hematoma without subarachnoid hemorrhage are rare. It is suggested that CT scans and history of patients are most important but an emergency angiography was prerequisite for correct diagnosis. Surgical treatment should be the best management in such cases.

Acute Disease↗