Biomedical subjects

T Kanayama

Publications and source records attributed to T Kanayama.

At least 19 recordsLinked to original sources

PubMed2001

Formation of metal-encapsulating Si cage clusters.

We report the formation of a series of metal-containing hydrogenated silicon clusters using an ion trap. Mass analyses reveal that many types of transition metal ions M(+) ( M = Hf, Ta, W, Re, Ir, etc.) react with silane (SiH4) to form dehydrogenated MSi( +)(n) cluster ions ( n = 14, 13, 12, 11, 9, respectively) as an end product, indicating that the metal atom is endohedral and stabilizes the Si polyhedral cage. This finding is confirmed by our ab initio calculation that WSi12 is a W-encapsulating Si12 cage cluster, and is very stable owing to both the electronic and the geometrical shell closures.

Journal Article↗

PubMed2000

Regional differences of metabolism in human masseter muscle by two-dimensional 31P-chemical shift imaging.

Many reports have demonstrated significant region-dependent differences in the fiber-type composition of the human masseter muscle. Therefore, it is considered that there is intramuscular heterogeneity of metabolic activity in the muscle. The present study was carried out, with two-dimensional Chemical Shift Imaging, to detect differences between the deep and superficial parts of the human masseter muscle at rest. Masseter muscle from 11 volunteers, from 20 to 27 years old, was examined, and characteristic spectra of the inorganic phosphate (Pi), phosphocreatine (PCr), and alpha-, beta-, and gamma-adenosine triphosphate (ATP) from each part of the muscles were obtained. In this study, the deep and superficial parts of the masseter muscle were distinguished by the existence of aponeurosis. The Pi/PCr, PCr/beta-ATP, and Pi/beta-ATP ratios as well as the pH in the deep and superficial parts were calculated from the peak spectra. Compared with the deep part, the Pi/PCr of the superficial part was lower (p < 0.05) and the PCr/beta-ATP was higher (p < 0.01). The Pi/beta-ATP and pH showed no significant differences between the two parts. The results indicate that the superficial part of the masseter muscle contains more PCr than the deep part, and this may be related to functional differences between these two parts. In future examinations of the metabolic activity of the human masseter muscle, the deep and superficial parts must be measured separately.

Adenosine Triphosphate↗

PubMed1999

Molecular weight independence of the effect of additive hyaluronic acid on the lubricating characteristics in synovial joints with experimental deterioration.

OBJECTIVE: To assess the molecular weight dependence of the lubricating characteristics of additive hyaluronic acid in animal joints with experimental deterioration. DESIGN: An experimental study in rabbits stifles in vitro. BACKGROUND: Hyaluronic acid is used as a drug for osteoarthritis. However, the molecular weight dependence of the effect of hyaluronic acid has been unclear. METHODS: Using a robotic arm under force-control, frictional coefficients were measured in fourteen rabbit stifles. The experimental conditions examined were: (1) intact joint surfaces; (2) after the joint surfaces were washed with physiological saline; (3) after the addition of 1% hyaluronic acid solution with a molecular weight of one million daltons and two million daltons, respectively. RESULTS: The increased frictional coefficient produced by washing with saline was decreased significantly by the addition of hyaluronic acid to the joint surfaces. This effect was observed regardless of the molecular weight of the hyaluronic acid. CONCLUSION: The lubricating characteristics of hyaluronic acid in synovial joints do not change with molecular weight. RELEVANCE: Hyaluronic acid solution is used clinically for the treatment of osteoarthritis. In the present study, the molecular weight dependency of the lubricating characteristics of hyaluronic acid was tested using the friction in synovial joints.

Animals↗

PubMed1999

Analysis of glycosaminoglycans in rabbit cornea after excimer laser keratectomy.

BACKGROUND/AIMS: The biochemical basis for the development of subepithelial opacity of the cornea after excimer laser keratectomy has yet to be fully defined. The aim of this study was to evaluate the alterations of glycosaminoglycans (GAGs) after excimer laser keratectomy. METHODS: Rabbit corneas were harvested on days 5, 10, 20, and 30 after excimer laser photoablation. The amount of main disaccharide units was determined by high performance liquid chromatography (HPLC). In addition, immunohistochemical studies were performed on corneal sections 20 days after the ablation. RESULTS: The concentrations of DeltaDi-0S at 5 and 10 days were significantly lower than before the ablation. DeltaDi-6S showed a significant increase 5 days after the ablation but DeltaDi-4S did not show any significant change. There was a significant increase in DeltaDi-HA at 20 and 30 days after ablation. In immunohistochemistry, the positive staining for DeltaDi-6S and hyaluronic acid was observed in the subepithelial region. These immunohistochemical results were well correlated with the HPLC findings. CONCLUSIONS: The increase in chondroitin-6 sulphate and hyaluronic acid may be related to corneal subepithelial opacity after excimer laser keratectomy.

Animals↗

PubMed1997

Fluoride profiles in the cementum and root dentine of human permanent anterior teeth extracted from adult residents in a naturally fluoridated and a non-fluoridated area.

OBJECTIVES: To determine the effect of water fluoride concentration on the fluoride profile across the entire thickness of the cementum and root dentine of human permanent anterior teeth in adults. SUBJECTS: Twenty-eight human permanent anterior teeth from individuals aged from 30 to over 60 years were studied. SETTING: Teeth were obtained from a natural high-fluoride area (West Hartle-pool, UK; 1.0-1.3 ppm F in drinking water, WHP) and the other from a non-fluoridated naturally low fluoride area (Leeds, UK; 0.1 ppm F in drinking water, LDS). DESIGN: Cementum and root dentine were sampled using an abrasive micro-sampling technique from the cementum surface to the pulpal surface of root dentine. RESULTS: Fluoride concentration was higher in tooth roots (the cementum and dentine) taken from the naturally fluoridated area (WHP) than from the non-fluoridated area (LDS). Age and average fluoride concentration showed a positive correlation in WHP dentine, middle region of the root (r = 0.78, P < 0.001) and in the apical region of the root (r = 0.61, P < 0.05). WHP cementum had the strongest fluoride concentration correlation with age in the cervical region of the root (r = 0.67, P < 0.01). An analysis of variance (ANOVA) showed that the area (water fluoride content), age and number of years lived in the area combined with total age were significant. CONCLUSIONS: The fluoride content of cementum and root dentine in adult residents is related to fluoride content in drinking water.

Adult↗

PubMed1997

Earthquake damage to a laboratory animal facility.

Our seven-storey laboratory animal facility was damaged during the 1995 earthquake of magnitude 7.2. The seismic intensity experienced at our facility was estimated to be around 5 on the Japanese version of the Richter scale (a very strong shock). However, no damage was sustained to the water, gas or electricity supplies in many of the offices, the upper drawers of the steel cabinets fell to the floor. In the animal-rooms, while the floor-fixed cage-racks were hardly damaged, most of the movable cage-racks were dislodged by the shocks. We describe here our countermeasures, including those taken prior to the earthquake.

Animals↗

PubMed1997

[Effects of biochemical modulation chemotherapy with CDDP and 5-FU on metastatic brain tumor from lung cancer].

Fourteen cases of metastatic brain tumors from lung cancer underwent biochemical modulation chemotherapy with daily administration of small doses of CDDP (5 or 10 mg/day) and continuous infusion of 5-FU (300 mg/day) for three tow six weeks. All patients with metastatic brain tumors also underwent a total of 30 Gy of whole brain irradiation therapy. Of eleven patients who had metastatic brain tumors when chemotherapy started, complete and partial responses were shown in two patients each (36% response rate). Moreover, only four of twelve patients with extracranial lesions responded (33% response rate). Abnormal levels of tumor marker were improved in only three of 10 evaluable patients (30% response rate). Side effects of this chemotherapy included various WHO grades of bone marrow suppression as well as nausea and vomiting in 13 of 14 patients. Loss of appetite persisted for two months. Parkinsonism was also noted in three patients as an additional side effect. Mean survival time was 9.4 months, while 4 patients survived longer than one year. Data showing a low response rate, persistent loss of appetite and longer admission period were considered less favorable than those of other chemotherapeutic regimens.

Adenocarcinoma↗

PubMed1997

[Intravenous anesthesia by continuous administration of midazolam and fentanyl].

We examined the amount and method of administration of midazolam and fentanyl for intravenous anesthesia. Intravenous anesthesia was induced by intravenous administration of fentanyl 0.2-0.3 mg, followed by a minimal sleeping-inducing dose of midazolam, and then an additional 0.2 mg of fentanyl before starting the operation. To maintain anesthesia, a half dose of the first dose of midazolam was administered every hour, and a continuous intravenous injection of fentanyl at 0.08 microgram-1. kg-1.min-1 was also performed. It is suggested that these doses are the most suitable for obviating the use of antagonist. Also, by using a continuous administration, the dose of fentanyl can be reduced, and it is possible to stabilize circulation. Without the use of nitrous oxide during intravenous anesthesia, it is necessary to double the dose of fentanyl administered.

Adult↗

PubMed1997

[X-ray microscope].

Explore the source record for details and available documents.

Electron Probe Microanalysis↗

PubMed1997

[Long-term complete response in two cases of liver metastases from rectal and gastric cancer treated with intra-arterial infusion chemotherapy of leucovorin and 5-fluorouracil].

Intra-arterial infusion chemotherapy combined with leucovorin (LV) and 5-fluorouracil (5-FU) was performed in two patients with multiple metastases from rectal and gastric cancer. In each patient LV 45 mg was infused as a bolus just before and after 5-FU 1,000 mg/4 hrs administration. Thereafter 5-FU dose was decreased gradually. This regimen was principally repeated weekly on an outpatient basis. In both patients PR was detectable 3 and 4 months after the beginning of chemotherapy, and CR was obtained in 21 and 6 months, respectively. Neither patient showed any signs of recurrence and are in good health 35 and 30 months after initiation of chemotherapy. These findings suggest that our protocol has an excellent anti-tumor effect and improves the QOL in some patients for a long time.

Adenocarcinoma↗

PubMed1996

Difference in CDDP penetration into CSF between selective intraarterial chemotherapy in patients with malignant glioma and intravenous or intracarotid administration in patients with metastatic brain tumor.

Platinum (Pt) levels in plasma and cerebrospinal fluid (CSF) in patients with malignant glioma were determined after initiation of selective intraarterial chemotherapy with a combination of VP-16 (etoposide) and CDDP (cisplatin), and were compared with the CSF Pt levels in patients with metastatic brain tumors after intravenous or intracarotid administration of VP-16 and CDDP. CSF Pt levels were also compared for various administration routes, doses, CSF sampling routes and blood-CSF barriers in metastatic brain tumor. Changes in the blood-CSF barrier to CDDP during treatment in a patient with meningeal lymphoma and in a patient recovering from surgical removal of a metastatic brain tumor were also examined by periodic administration of CDDP. All CSF samples were taken through Ommaya reserviors placed in the anterior horn of the lateral ventricle or the postoperative cavity. The mean peak CSF/plasma total Pt ratio (T/T ratio) and the mean CSF total Pt/plasma ultrafiltrable Pt ratio (T/U ratio) were highest (15.0% and 24.4%, respectively) following selective intraarterial infusion of CDDP in patients with malignant glioma, followed by intravenous infusion in meningeal carcinomatosis (11.5% and 18.9%), intracarotid administration (5.4% and 8.7%) and intravenous infusion (60 mg/m2 2.5% and 100 mg/m2 2.9%; and 60 mg/m2 3.5% and 100 mg/m2 7.7%) in patients with the solid type of metastatic brain tumor. In CSF obtained from the postoperative cavity in cases of metastatic brain tumor, T/T and T/U ratios were extremely high (40.9% and 62.4%). However, the CSF Pt level even after selective intraarterial administration of CDDP in malignant glioma was 0.51-1.64 micrograms/ml total Pt and 0.43-1.08 micrograms/ml ultrafiltrable Pt. Even the CSF level obtained from the postoperative cavity was 1.0-4.7 micrograms/ml total Pt. These low levels of total and ultrafiltrable Pt are considered not to be cytotoxic to disseminated cells in the CSF space and to normal brain cells. As for changes in the blood-CSF barrier, repeated administration of CDDP showed that the rate of entry of Pt into the CSF decreased in parallel with improvements apparent on CT scans in the patient with meningeal lymphoma, and also showed that the blood-CSF barrier to Pt was gradually repaired after the metastatic brain tumor had been removed.

Antineoplastic Agents, Phytogenic↗

PubMed1996

Cancer-associated retinopathy syndrome: a case of small cell lung cancer expressing recoverin immunoreactivity.

Cancer-associated retinopathy (CAR) syndrome is a rare paraneoplastic neuropathy syndrome often found in patients with small cell lung cancer (SCLC). Serological studies have indicated that the process could include autoimmune reactions directing retinal antigens. Recently, the CAR antigen was identified as a photoreceptor protein, recoverin, by screening retinal proteins using the CAR patient's serum. The present case of SCLC showed rapidly deteriorated bilateral visual acuity lacking the inflammatory findings at the retina which were compatible with CAR. The immunohistochemical study revealed that the cancer cells expressed recoverin or recoverin-like immunoreactivity. This is the first observation in CAR syndrome. The presence of recoverin or recoverin-like immunoreactivity in SCLC with CAR syndrome supports the hypothesis that the cancer-retina immunologic cross-reaction contributes to visual loss in this syndrome.

Aged↗

PubMed1995

Glucose retention on the surfaces of primary teeth in 3- and 4-yr-old children.

Glucose retention was determined in 38 kindergarten children ages 3-4 yr. The children rinsed their mouths with 10 ml of a 0.5 mol/l glucose solution for 15 s and then spat out. Three minutes after they put the solution in their mouths, a small paper-point was used to collect samples of saliva from the labial and buccal surfaces of the maxillary and mandibular primary teeth. The concentration of glucose in the small amount of saliva collected was measured with an immobilized enzyme system. Glucose retention was highest on the maxillary central primary incisor, second highest on the maxillary first primary molar and third highest on the maxillary lateral primary incisor. An intermediate value was seen on the maxillary and mandibular second primary molars, the mandibular first primary molar and the maxillary primary canine. A lower value was observed on the mandibular primary canine and the lowest on the mandibular incisors. It was concluded that there were site differences in glucose retention on primary teeth of 3- and 4-yr-old children.

Analysis of Variance↗

PubMed1995

Fluoride distribution of rat molar cementum in relation to age and fluoride levels in the drinking water.

The present study was undertaken to determine the fluoride distribution profile in rat molar cementum with age in relation to fluoride in drinking water. Fifty-four female Wistar rats were used for the experiment. Before the experiment 6 rats were killed under chloroform anesthesia at 4 weeks of age as controls. The remaining 48 rats were divided into two groups: a control group given distilled water and the other group given water containing 100 ppm fluoride ad libitum. Six rats from each group were killed at the ages of 6, 12, 24, and 48 weeks. The fluoride distribution in the molar cementum was analyzed from the surface to the cementodentinal junction by abrasive microsampling. The fluoride concentrations in molar cementum from control rats on distilled water remained relatively constant until 24 weeks. A small increase then occurred between 24 and 48 weeks. The fluoride concentration in cementum from rats drinking water containing 100 ppm fluoride increased markedly with age, both in outer and inner regions of the molar cementum for all rats. On the other hand, the fluoride concentration in the cementum of older rats drinking water with 100 ppm fluoride was significantly higher in the outer than in the inner region of the cementum. It was concluded that the fluoride distribution in rat molar cementum may increase throughout life in relation to the fluoride level in the drinking water.

Age Factors↗

PubMed1994

Opposite effects of midazolam and beta-carboline-3-carboxylate ethyl ester on the release of dopamine from rat nucleus accumbens measured by in vivo microdialysis.

This report describes the effects of midazolam and beta-carboline-3-carboxylate ethyl ester (beta-CCE) on extracellular concentrations of dopamine in the nucleus accumbens of freely moving rats measured by in vivo microdialysis. The two compounds had opposite effects, midazolam (0.075 and 0.15 mg/kg i.v.) dose dependently decreasing, and beta-CCE (3 and 10 mg/kg i.p.) dose dependently increasing, dialysate concentrations of dopamine. Flumazenil (6 micrograms/kg i.v.) did not affect the efflux of dopamine but it prevented the effects of both midazolam and beta-CCE on dopamine efflux. N6-Cyclohexyladenosine (0.1, and 1 mg/kg i.p.), a selective adenosine A1 agonist, dose dependently increased the efflux of dopamine. This effect was blocked by 8-cyclopentyl-1,3-dipropylxanthine (25 mg/kg i.p.), a selective adenosine A1 receptor antagonist, a dose which given alone did not affect dopamine efflux; responses to midazolam were not affected. 3,7-Dimethyl-1-propargylxanthine (1 and 3 mg/kg i.p.), a selective adenosine A2 receptor antagonist, did not mimic the effects of beta-CCE. The results suggest that midazolam and beta-CCE modulate dopamine release in the nucleus accumbens by an action at the benzodiazepine binding site associated with the GABAA receptor complex.

Adenosine↗

PubMed1994

Selective intra-arterial chemotherapy with a combination of etoposide and cisplatin for malignant gliomas: preliminary report.

We administered selective intra-arterial chemotherapy consisting of a combination of etoposide and cisplatin to 20 patients with malignant glioma (seven with recurrent and six with enlarged tumors after initial treatment, and seven newly diagnosed patients). Evaluation of efficacy was based on computed tomographic and magnetic resonance imaging findings. In the process of establishing a safe technique for superselective intra-arterial chemotherapy, we encountered cerebrovascular accidents in two patients (after etoposide in one and after etoposide plus cisplatin in the other). In these two cases, 100 mg/m2 of etoposide and 100 mg/m2 of cisplatin were delivered via the horizontal segment of the middle cerebral artery (M1) or the tip of the basilar artery, with the infusion time reduced to 20 minutes. Thereafter, the etoposide was diluted, and the doses of both drugs were reduced to 80 or 50 mg/m2, and finally to 60 mg/m2, and both were infused over 60 minutes. In addition, for prevention of local spasm, papaverine hydrochloride and nicardipine were given via the same catheter at 5-minute intervals during administration of etoposide and cisplatin. No complications developed in the later cases. Thereafter, selective intra-arterial infusion of etoposide and cisplatin into the anterior cerebral artery, middle cerebral artery, posterior cerebral artery, or the basilar artery for malignant gliomas in the basal ganglia, internal capsule, and brainstem--a procedure generally considered risky in terms of potential complications--was performed safely, with tolerable side effects. Computed tomography and magnetic resonance imaging indicated improvement in 13 patients, including four whose tumors completely disappeared. This method of intra-arterial chemotherapy may be useful as an adjuvant treatment for malignant glioma.

Adolescent↗

PubMed1994

Myelin basic protein in the cerebrospinal fluid of patients with brain tumors.

We measured the level of myelin basic protein (MBP) in the cerebrospinal fluid (CSF) of patients with various kinds of tumors, including malignant tumors, using radioimmunoassay. The CSF had been obtained by lumbar puncture through an Ommaya reservoir or a shunt device placed in the lateral ventricle. The level of MBP was high (> 4 ng/ml) in the patients with meningeal dissemination of malignant tumors, but in those who showed a good response to chemotherapy and/or radiation, it decreased or returned to the normal level, with improvement on the computed tomography and magnetic resonance imaging, cytological, general CSF, and neurological findings. Of seven malignant gliomas without CSF dissemination, six showed an elevated level of MBP before selective intra-arterial chemotherapy with a combination of etoposide and cisplatin administered via a microcatheter placed at A1, M1, P1-P2, and the basilar top. All CSF specimens obtained during the period of the intra-arterial chemotherapy showed an abnormally high (> 4 ng/ml) level of MBP that exceeded the prechemotherapy level. The MBP level decreased or returned to normal in the patients with a good response to chemotherapy after intra-arterial chemotherapy. In some patients with multiple metastatic brain tumors, the MBP level was elevated before treatment and returned to normal after treatment (surgical removal, chemotherapy, and/or irradiation) in all except one. Thus, there was a clear correlation between the timing of treatment and changes in imaging studies and MBP levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Myelin basic protein in the cerebrospinal fluid of patients with neurological disease: especially with malignant brain tumors].

Myelin basic protein (MBP) in the cerebrospinal fluid (CSF) of patients with brain tumors and other neurological diseases was measured before, during and after various treatments such as surgery, chemotherapy and irradiation. We assessed the significance of changes in the MBP levels during the course of treatment, and speculate on what the elevated level of MBP in brain tumor patients indicates. In meningeal dissemination of malignant tumors, meningeal carcinomatosis from cancer of the systemic organ showed the highest level of MBP followed by meningeal gliomatosis and meningeal lymphoma. Meningeal carcinomatosis and meningeal lymphoma, which have responded to chemotherapy, showed normal levels of MBP after chemotherapy. Six of eight patients with newly diagnosed malignant glioma showed moderate to high levels of MBP (range 4.6-35.5ng/ml) just before intraarterial chemotherapy with VP-16 and CDDP. The level increased in five patients during the course of chemotherapy and then decreased in relation to the degree of tumor reduction by chemotherapy. In the solid type of metastatic brain tumor, five of seven patients with multiple tumors showed high levels of MBP and these levels also returned to normal after treatment in four patients. As for the influence of irradiation, levels of MBP did not increase after irradiation except in three patients who developed radiation necrosis, local extensive edema or atrophic change. In other brain tumors, levels of MBP were high in a patient with a large meningioma with very extensive edema and during an unstable postoperative condition after total removal of a large craniopharyngioma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗