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Biomedical subjects

M Nagayama

Publications and source records attributed to M Nagayama.

At least 73 records · Page 4Linked to original sources
PubMed1996

Non-decay type fast-setting calcium phosphate cement: setting behaviour in calf serum and its tissue response.

Non-decay type fast-setting calcium phosphate cement (nd-FSCPC) was evaluated in terms of its setting behaviour in calf serum and its tissue response to investigate the feasibility of its clinical use in surgical applications. Non-decay type cements were prepared by adding various amounts of sodium alginate to the liquid phase of base cements, fast-setting calcium phosphate cement (FSCPC) and conventional calcium phosphate cement (c-CPC). Cement pastes were immersed in serum at 37 degrees C immediately after mixing, and decay behaviour, setting time and mechanical strength were measured to evaluate the possibility of their use in surgical applications. Also, nd-FSCPC was implanted into rat subcutaneous tissue for the initial evaluation of biocompatibility of this potential bioactive cement. nd-FSCPC set in approximately 6-7 min in serum, even when the cement paste was immersed in the serum immediately after mixing, whereas c-CPC and FSCPC decayed completely upon immersion. nd-FSCPC transforms to hydroxyapatite (HA) within 24 h and shows a diametral tensile strength of approximately 4-5 MPa. As a result of transformation to HA, nd-FSCPC showed excellent tissue response when implanted subcutaneously in rats. We conclude that nd-FSCPC has good potential value for use in orthopaedics, plastic and reconstructive surgery, and oral and maxillofacial surgery, where the cement is exposed to blood.

Animals↗
PubMed1996

Verruciform xanthoma occurring within oral lichen planus.

A verruciform xanthoma occurring within lichen planus on the lateral aspect of the tongue in a 68-year-old Japanese woman is reported. The features suggest that the condition of altered epithelial turnover, as in repeated epithelial desquamation, may cause the verruciform xanthoma.

Aged↗
PubMed1996

Distinctive serial magnetic resonance changes in a young woman with rapidly evolved neurocysticercosis, with positron emission tomography results.

A woman aged 21 years noticed numbness of the left hand, dysarthria, and right hemiparesis. Magnetic resonance imaging (MRI) showed homogeneously enhanced lesions in the bilateral cerebral white matter; these enlarged within 2 weeks, showing ring-like enhancement, and then spontaneously decreased in size and enhancement. Neurocysticercosis was confirmed by repeated, significantly positive serology results and the dramatic response to praziquantel. Subsequently, positron emission tomography (PET) revealed persisting regions of possibly decreased cerebral uptake of [18F]2-fluoro-2-deoxyglucose. This is the first documentation of such distinctive serial MRI changes and the results of PET in neurocysticercosis.

Adult↗
PubMed1996

Fatal familial insomnia with a mutation at codon 178 of the prion protein gene: first report from Japan.

Fatal familial insomnia (FFI), or familial selective thalamic degeneration with a mutation at codon 178 of the prion protein (PrP) gene, is a rapidly progressive autosomal dominant disease characterized by progressive insomnia, dysautonomia, and myoclonus. We report here the clinical and postmortem findings as well as genomic analysis in a first non-Western case with FFI. This patient also clinically had cognitive impairments such as memory disturbance, delirium, and hallucinations, along with insomnia, dysautonomia, and myoclonus. This case implies a worldwide distribution of FFI and also highlights the need for more aggressive clinical application of genomic analysis of the PrP gene and polysomnographic study in patients with insomnia and cognitive impairments.

Humans↗
PubMed1996

Changes in myocardial lactate metabolism during ramp exercise in patients with effort angina and microvascular angina.

Changes in myocardial lactate metabolism during ramp exercise were investigated through great cardiac vein catheterization in 15 patients with effort angina (EA) and 7 patients with microvascular angina (MVA). The exercise test was performed using a supine bicycle ergometer. Blood samples were obtained from the great cardiac vein (GCV) and the radial artery each minute during exercise. Patients in the EA group showed a point at which the lactate extraction ratio (LER) and the ST level decreased rapidly during exercise. This point was clearly recognized in 12 of 13 patients, and may represent the ischemic threshold. Both the LER and ST level showed similar changes during exercise, and these values were significantly different between the ischemic threshold and peak exercise (p < 0.01). Both the LER and ST level were strongly correlated with the duration of exercise until the threshold (r = 0.703). In the MVA group, both the LER and ST level during exercise continuously decreased throughout exercise without an ischemic threshold in all of the subjects. Endomyocardial biopsy revealed sclerosis of small arteries in the myocardium in all of the patients. In both effort angina and microvascular angina, a close correlation was noted between the change in ST and that in the myocardial lactate extraction ratio.

Adult↗
PubMed1996

Effects of selected organophosphate insecticides on serum cholinesterase isoenzyme patterns in the rat.

The serum cholinesterase (ChE) isoenzyme in rats shows 6 bands after polyacrylamide gradient gel electrophoresis. The effects of organophosphates (fenthion, chlorpyrifos, diazinon, bromophos, propaphos, haloxon, and DFP) on serum ChE isoenzyme bands were studied in 32 male and 32 female 6-w-old Sprague-Dawley rats. Each organophosphate was randomly administered to 4 male and 4 female rats. Blood samples were collected from the abdominal aorta under halothane anesthesia 6 h after dosing. The isoenzyme patterns were determined simultaneously with erythrocyte and serum ChE activities. Changes were observed in all 6 bands of the serum ChE isoenzymes after administration of fenthion, chlorpyrifos and propaphos. Diazinon had no influence on band 6, and DFP and bromophos had no influence on band 5. Haloxon did not effect any of the serum ChE isoenzyme bands. Serum ChE was most suppressed by fenthion, followed by DFP, bromophos, chlorpyrifos, propaphos and diazinon in that order of effect. Serum ChE activity was not suppressed by haloxon. Erythrocyte ChE activity was suppressed by every organophosphate. This experiment demonstrated a correlation between the organophosphate suppression of serum ChE activity and the concentration of serum ChE isoenzyme band 6.

Analysis of Variance↗
PubMed1996

[An adult case of homocystinuria probably due to methylenetetrahydrofolate-reductase deficiency--treatment with folic acid and the course of coagulation-fibrinolysis parameters].

We report a rare male case of homocystinuria probably due to methylenetetrahydrofolate-reductase deficiency. The onset of his disorder was at 19 years of age, and he had no family history. He initially developed gait disturbance, and then generalized seizure in several months, which made him admitted to our hospital. Neurological examinations revealed mental dysfunction, spastic paraplegia, cerebellar ataxia, and sensory disturbance in his feet. MRI showed multiple increased intensities on T2-weighted images in the cerebral white matter. EMG revealed neurogenic changes. These symptoms and signs slowly progressed, and he then developed thrombophlebitis in his lower extremities. Thrombin-antithrombin III complex (TAT) and D-dimer remained high continuously, and plasma homocysteine level was more than ten times higher than the normal range. Plasma cystathionine level was high and methionine level was low. The serum folic acid, vitamin B12, and methylmalonic acid in the urine were normal. Megaloblastic anemia was not seen. Based on these data, he was diagnosed to have homocystinuria probably due to methylenetetrahydrofolate-reductase deficiency. Treatment with high doses of folic acid, pyridoxine and cobalamin normalized plasma cystathionine and methionine levels, and markedly decreased plasma homocysteine, although it remained about three times higher than the normal range. Thereafter, both TAT and D-dimer levels also markedly decreased. The administration of folic acid reduced elevated plasma homocysteine as well as the coagulation--fibrinolysis factors. This implies that they may serve as useful markers for effective treatment of this disease.

Adult↗
PubMed1995

Osteogenesis by human osteoblastic cells in diffusion chamber in vivo.

Osteogenic potential of osteoblastic cells isolated from human bone was evaluated by a diffusion chamber method. Cells placed in diffusion chambers were implanted intraperitoneally into the athymic mice. The diffusion chambers cultured in vivo were harvested and examined after implantation for 6-8 weeks. The content of the chamber was proved by a soft roentogenogram to contain the radioopaque area. Light microscopic study revealed that this area was made up of bone-like nodule. Within the diffusion chambers, the cell layers were observed alongside the interior surface of the membrane filters, and mineralized nodules were formed among the cell layers. The mineralized nodules were confirmed by staining with the von Kossa technique for calcium mineral deposits. In electron microscopic study, the osteoblastic cells had a relatively large nuclei, and an abundant rough endoplasmic reticulum produced numerous extracellular matrix. In the bone-like nodules, the osteoblastic cells were surrounded by a heavily mineralized matrix with nonmineralized matrix separating the osteoblastic cells from the mineralized matrix. The mineralized matrix contained well-banded collagen fibrils. Matrix vesicles and collagen fibrils which were closely associated with mineral deposition were observed at the mineralizing front. These results together with our previous report [13] indicate that isolated human osteoblastic cells possessed osteogenic potential in vivo as well as mineralization activity in vitro.

Animals↗
PubMed1995

Non-decay type fast-setting calcium phosphate cement: composite with sodium alginate.

Non-decay type fast-setting calcium phosphate cement (nd-FSCPC) was prepared by introducing sodium alginate (0-2.0 wt%) into the liquid phase of FSCPC. nd-FSCPC was stable even when the cement paste was immersed in distilled water immediately after mixing, whereas conventional FSCPC (c-FSCPC) decayed completely within 1 min upon immersion. The setting time of the cement, approximately 5 min, was not dependent on the presence of sodium alginate. In contrast, the introduction of sodium alginate into conventional CPC, i.e. CPC without neutral phosphate in the liquid phase, resulted in no setting when the amount of sodium alginate introduced was more than 1 wt%. Powder X-ray diffraction analysis revealed no significant difference for the conversion of cement to apatite for any concentrations of sodium alginate studied (0-2.0 wt%). The mechanical strength of the cement increased rapidly with the addition of sodium alginate up to 0.8 wt% when the cement paste was immersed and kept in distilled water at 37 degrees C, whereas further addition of sodium alginate decreased the mechanical strength. The results obtained in this investigation, taken together with sodium alginate's known excellent biocompatibility and absorption behaviour, indicate that the use of sodium alginate composite FSCPC as nd-FSCPC should be of value in orthodontics and oral and maxillofacial surgery where the cement is exposed to blood.

Alginates↗
PubMed1995

In vivo setting behaviour of fast-setting calcium phosphate cement.

The in vivo setting behaviour of fast-setting calcium phosphate cement (FSCPC) between femoral muscles of the rat was investigated to evaluate the possible value of FSCPC for medical and dental application. Conventional CPC (c-CPC) and FSCPC were implanted between femoral muscles, and various aspects of the setting behaviour such as setting time, mechanical strength and conversion ratio of cement into hydroxyapatite (HAP: Ca10(PO4)6(OH)2) were measured by the Vicat needle method, diametral tensile strength (DTS) measurement, and quantitative powder X-ray diffraction (XRD) analysis, respectively. The setting time of FSCPC in vivo was 5-7 min, in contrast to 48 min for c-CPC. As a result of its fast setting, set specimens of FSCPC showed higher mechanical strength from the initial stage than c-CPC. Higher DTS values were observed in FSCPC than c-CPC implanted after 24 h. Powder XRD analysis revealed faster conversion of FSCPC than c-CPC into HAP, which was responsible both for the faster setting and higher mechanical strength from the initial stage. We concluded, therefore, that FSCPC may be used for a wide range of clinical applications, i.e. fields where fast setting is required such as orthopaedic, plastic and reconstructive, and oral and maxillofacial surgery.

Animals↗
PubMed1995

Simultaneous production of G- and M-CSF by an oral cancer cell line and the synergistic effects on associated leucocytosis.

We established a novel cell line, TSU, from a oral cancer patient with marked leucocytosis. The culture supernatant of TSU cells promoted granulocytic colony formation by mouse bone marrow cells, indicating that TSU produced granulocyte-colony stimulating factor (G-CSF). The concentration of G-CSF was 2.45 micrograms/mg protein, measured by enzyme-linked immunosorbent assay (ELISA). The maximum number of colonies induced by TSU culture supernatant was more than that achieved with recombinant human G-CSF (rhG-CSF) and the size of the colonies induced by TSU supernatant was obviously larger than those achieved with rhG-CSF. The activity of TSU supernatant was completely inhibited by antihuman G-CSF and macrophage-colony stimulating factor (M-CSF) antibodies, but was only partially inhibited by antihuman G- or M-CSF antibody alone. These results indicate that not only G-CSF but also M-CSF, both of which could be produced by TSU cells, are involved in causing leucocytosis; the results suggest that the synergistic production of G- and M-CSF could play an important role in the leucocytosis associated with oral cancer.

Colony-Forming Units Assay↗
PubMed1995

Evaluation of serum concentration of parathyroid hormone-related protein and its implication in hypercalcemia in squamous cell carcinoma of the head and neck.

Hypercalcemia is a common and serious complication associated with squamous cell carcinoma (SCC) and is considered to be caused by a tumor-derived factor, parathyroid hormone-related protein (PTHrP). However, the correlation between serum levels of calcium and PTHrP and the kinetics of PTHrP in SCC of the head and neck is unknown, because the behavior of the circulating form of PTHrP in patients has not been determined. In the present study, the PTHrP concentrations in serum samples from 54 patients (37 with SCC and 17 with benign tumors) were measured by a recently developed radioimmunoassay directed toward the C-terminal region of PTHrP, and the laboratory data including those calcium levels in corresponding samples were reviewed retrospectively. Results showed hypercalcemia in four patients with advanced cancer and in whom elevation of the serum PTHrP concentration was observed simultaneously. The regression analysis also revealed the linear relationship of the calcium level to the PTHrP concentration, but not to the concentration of phosphorus or creatinine, suggesting that monitoring of serum PTHrP level is useful for prediction of hypercalcemia associated with head and neck cancer.

Adult↗
PubMed1995

Familial hyperparathyroidism associated with jaw fibroma: case report and literature review.

A 53-year-old female suffering from renal stones and hypercalcaemia was diagnosed as having primary hyperparathyroidism caused by hyperplasia of the parathyroid glands. She underwent total parathyroidectomy and implantation of parathyroid tissue. After one year, she underwent surgery for a jaw tumour. The pathological findings indicated it to be a cementifying fibroma. Jackson et al. (1990) reported the familial association of hyperparathyroidism with jaw tumours, and they suggested that this condition represents a new clinical syndrome. We believe that our case belongs to this syndrome.

Female↗
PubMed1995

Effect of 2, 3, 4, 7, 8-pentachlorodibenzofuran and its analogues on induction of sister chromatid exchanges in cultured human lymphocytes.

We have been already contaminated with various chemicals including highly toxic organochlorine compounds such as 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF) and 3, 4, 5, 3', 4'-pentachlorobiphenyl (Co-PenCB). In this study, in order to evaluate the genotoxicity of the three chemicals, we have examined their effects on the induction of sister chromatid exchanges (SCEs), which has been frequently utilized as an indicator of biological and genetic damage due to exposure to carcinogens or mutagens, in cultured human lymphocytes in the absence or presence of 7, 8-benzoflavone (ANF) and the following results were obtained. 1) TCDD, PenCDF and Co-PenCB significantly increased the frequency of SCEs with almost the same dose-dependent manner in terms of the concentration of TCDD toxic equivalent. 2) 8 x 10(-5) MANF significantly enhanced the frequency of SCEs and the simultaneous treatment of ANF and either of TCDD, PenCDF or Co-PenCB seemed to exert an additive effect as SCEs inducer. 3) TCDD, PenCDF and Co-PenCB were considered to be very potent inducers of SCEs, because their 50% effective concentration in SCEs enhancement were only 5 to 10 times higher than the level of the adipose tissue in healthy Japanese, namely, 70ppt as TCDD. Consequently, the respective TCDD toxic equivalency factors of 0.5 and 0.2 for PenCDF and Co-PenCB seemed to be reasonable so far as the induction of SCEs was employed as an indicator of the genotoxic potency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Influence of five methylsulphonyl PCB congeners on frequency of micronucleated cells in cultured human lymphocytes by cytokinesis block method.

The lungs and blood of Yusho patients and healthy Japanese people have already been contaminated with methylsulphonyl polychlorinated biphenyls (MSF-PCBs) at relatively high concentration. Therefore, we should give due attention to their biological and toxicological effects to man. In this study, in order to mainly evaluate non-S-dependent genotoxicity of five MSF-PCB congeners, namely, 3-MSF-4, 5, 3', 4'-tetrachlorobiphenyl (TCB), 3-MSF-4, 5, 2', 3'-TCB, 3-MSF-2, 5, 2', 4', 5'-pentachlorobiphenyl (PenCB), 4-MSF-2, 5, 2', 3', 4'-PenCB and 4-MSF-2, 5, 2', 3', 5', 6'-hexachlorobiphenyl (HCB). We have examined their effects on the induction of micronucleated cells, which has been frequently used to estimate the dose of ionizing radiation and truly radiomimetic, non-S-dependent, clastogens, in cultured human lymphocytes in the absence or presence of 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF), 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) or 3, 4, 5, 3', 4'-pentachlorobiphenyl (Co-PenCB). The following results were obtained. 1) 4 x 10(-5) M7, 8-benzoflavone (ANF) significantly enhanced the frequency of micronucleated cells and all of the five MSF-PCB congeners failed to induce the formation of micronucleated cells at doses of 5.2 to 9.6 ppm, which were about 35,000 times higher than the concentrations in the lungs and adipose tissue of healthy Japanese people.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1994

Plasminogen activators and their inhibitors in non-small cell lung cancer. Low content of type 2 plasminogen activator inhibitor associated with tumor dissemination.

BACKGROUND: Evidence suggests that plasminogen activators and their inhibitors play an important role in tumor spread. METHODS: In this study, we measured the antigen levels of urokinase (u-PA), tissue plasminogen activator (t-PA), type 1 plasminogen activator inhibitor (PAI-1), and type 2 plasminogen activator inhibitor (PAI-2), and cancer tissue (19 adenocarcinomas and 19 squamous cell carcinomas) and normal lung tissue. RESULTS: u-PA, PAI-1, and PAI-2 antigen levels in cancer tissue were significantly higher than those in normal tissue (P < 0.001 in u-PA and PAI-1; P < 0.005 in PAI-2), whereas t-PA antigen levels in cancer tissue were significantly lower than those in normal tissue (P < 0.005). In case with lymph node involvement (LN+ cases), PAI-2 antigen levels were significantly lower than those in cases without lymph node involvement (LN- cases) (P < 0.02), whereas there was no difference in either u-PA or PAI-1 antigen levels between these two groups. Furthermore, u-PA antigen levels showed a significant positive correlation with PAI-2 antigen levels in LN- cases (r = 0.696; P < 0.005), although there was no correlation between these two parameters in LN+ cases. CONCLUSIONS: The antigen levels of u-PA, PAI-1, and PAI-2 in cancer tissue were significantly higher than those in normal tissue, and lower content of PAI-2 was associated with lymph node metastasis.

Adenocarcinoma↗
PubMed1994

Lipoprotein(a) and ischemic cerebrovascular disease in young adults.

BACKGROUND AND PURPOSE: Serum lipoprotein(a) level is genetically determined and remains almost constant throughout life. Based on this property, we investigated the serum lipoprotein(a) levels of ischemic stroke patients in the chronic stage (mean period after stroke, 27 months) and its relation to the types of ischemic stroke. METHODS: We measured serum lipoprotein(a) levels in 101 patients with chronic ischemic stroke and 37 normal control subjects, taking the clinical profiles into consideration. RESULTS: Lipoprotein(a) levels in patients with atherothrombotic stroke were 28.0 +/- 19.6 mg/dL (mean +/- SD), which were significantly (P < .01) higher than those in patients with lacunar stroke and in normal control subjects (16.4 +/- 13.5 and 11.7 +/- 10.5 mg/dL, respectively). The lipoprotein(a) levels in patients with atherothrombotic stroke were significantly higher in the subgroup who were a younger age at onset: onset before age 50 years, 35.3 +/- 20.5; onset at age 50 to 59, 35.4 +/- 21.7; onset at age 60 to 69, 17.0 +/- 12.8; and onset at age 70 or older, 16.3 +/- 6.8 mg/dL (P < .01 for onset before age 50 versus 60 to 69 years or 70 years or older; P < .01 for onset at 50 to 59 years versus 60 to 69 years or 70 years or older). Serum lipoprotein(a) was significantly increased (40.2 +/- 20.1 mg/dL) in young adults with atherothrombotic stroke (onset at younger than age 45 years) compared with that in patients older than 45 years (P < .01). CONCLUSIONS: We conclude that lipoprotein(a) is a genetic, independent, and critical risk factor for ischemic stroke, especially in young adults.

Adolescent↗