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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 343 records · Page 19Linked to original sources
PubMed1997

Radical formation from the reaction of combustion smoke with diphenylamine.

We have attempted to examine the effects of radical scavengers, such as amines and phenols, to trap gas-phase radicals produced from the combustion of Poly (methyl methacrylate)(PMMA), which might cause damage to a living body, using an electron spin resonance (ESR) spin-trapping technique. As a result, diphenylamine did not decrease the amount of radicals but rather increased it. It indicates that under the conditions of this study, gas-phase radicals were hardly trapped by radical scavengers and that the precursors to produce other kinds of radicals can exist. It was suggested that from the experiments using several peroxides, the precursors should be diacylperoxides produced from the combustion of PMMA.

Butylated Hydroxytoluene↗
PubMed1997

Differentiating histologic malignancy of primary brain tumors: pentavalent technetium-99m-DMSA.

UNLABELLED: This study assessed pentavalent 99mTc-DMSA uptake in primary brain tumors and evaluated the relationship between retention and histologic malignancy. METHODS: SPECT images of the brain were obtained at 30 min and 3 hr after intravenous administration of approximately 555 MBq 99mTc(V)-DMSA in patients with brain tumors. Sixty studies were performed in 57 patients and 63 lesions were demonstrated: 11 glioblastomas, 13 anaplastic astrocytomas (Grade 3), 11 astrocytomas (Grade 2), 18 meningiomas and 10 schwannomas. Uptake ratios, retention ratio and retention index were calculated and compared with tumor histology and malignancy grade. RESULTS: Approximately 95% of both benign and malignant primary brain tumors were demonstrated by 99mTc(V)-DMSA SPECT images. False negative was noted in three cases. The early uptake ratios were closely related to the tumor vascularity but had no statistically significant difference in the tumor histology or histologic malignancy. The delayed uptake ratio, retention ratio and retention index were higher in the malignant tumors than the benign tumors. CONCLUSION: Technetium-99m(V)-DMSA washout from the tumor was highly dependent upon its histology and histologic malignancy. The delayed uptake ratio considerably reflected tumor histology and differentiated benign tumors from malignant tumors. The retention ratio and retention index significantly reflected tumor histology and histologic grade of primary brain tumors and clearly distinguished between benign and malignant tumors with statistically significant difference (p < 0.05). These results could suggest the clinical utility of 99mTc(V)-DMSA in imaging primary brain tumors and differentiating their histological malignancy grade noninvasively.

Adolescent↗
PubMed1997

Stimulation of endosteal bone formation by local intraosseous application of basic fibroblast growth factor in rats.

We investigated the effects of local intraosseous application of basic fibroblast growth factor under physiologic conditions. An aqueous solution containing 0 (vehicle), 25, 100, or 400 micrograms of basic fibroblast growth factor was injected via a needle into the ilium of rats. Two weeks later, bone mineral density of the ilium was significantly increased (P < 0.01) with all three doses, and a dose-effect relationship was apparent. Light microscopy revealed proliferation of undifferentiated mesenchymal cells on the endosteal and trabecular surfaces, as well as apposition of newly formed bone on existing trabeculae. Intraosseous injection of basic fibroblast growth factor may be of use for the treatment of osteoporosis.

Administration, Topical↗
PubMed1997

[Incidence and clinical features of lung cancer in patients with idiopathic interstitial pneumonia].

We studied the incidence of lung cancer in the 599 patients with idiopathic interstitial pneumonia (IIP) who had visited to 37 institutions during 1991. In addition to 89 patients with lung cancer registered initially 29 were found during more than 4 years of follow-up, which indicates that annual incidence of lung cancer in these patients with IIP was a few percent. A total of 118 lung cancers accounted for 19.7% of all the IIP patients registered and also for 27.2% of the 435 IIP patients in whom a definite outcome was certified by this study. Most of the patients with lung cancer were older men who were heavy smokers. The distribution of histological types was not noteworthy. On the chest rentgenogrms, the tumors were found predominantly in the peripheral lung fields even in the patients with squamous cell cancer, but no apparent association with IIP lesion was observed. Surgical resection was done in only 52% of the patients with the disease at stage I or II; chemotherapy and/or radiotherapy were given to 52.4% of the patients with advanced disease, which may have been due to considerations of the adverse effects of anticancer treatment on the prognoses. The mortality in IIP patients with lung cancer was higher than in those without lung cancer, mainly due to progression of the lung cancer, not the IIP. This indicates the importance of lung cancer as a prognostic factor in patients with IIP.

Age Factors↗
PubMed1997

[A surgical case of severe Ebstein's anomaly, pulmonary atresia in the neonate: experience of modified Starnes operation].

We report a surgical case of severe Ebstein's anomaly associated with pulmonary atresia in the neonate. The baby had remarkable cardiomegaly (CTR > or = 90%) soon after birth and presented severe respiratory distress. He underwent modified Starnes operation (closure of tricuspid valve using a perforated patch, enlargement of interatrial communication, modified Blalock shunt, and PDA ligation) at the age of 12 days. He survived the procedure and cardiopulmonary failure was improved. However, he died from arrhythmia on the 3rd postoperative day. We think this procedure is useful regard to improvement of cardiopulmonary failure due to this fatal congenital heart disease.

Cardiac Surgical Procedures↗
PubMed1997

Localization of NADPH diaphorase and vasoactive intestinal polypeptide-containing neurons in the efferent pathway to the rat corpus cavernosum.

OBJECTIVE: We examined the coexistence of nitric oxide synthase (NOS) and vasoactive intestinal peptide (VIP) in the efferent pathway to the rat corpus cavernosum. METHODS: We used NADPH diaphorase (ND) histochemical staining, a specific marker of neuronal NOS, in combination with retrograde axonal transport of True Blue (TB) and VIP immunohistochemistry. RESULTS: Many neurons were labeled by TB in the cavernous nerve and the body of the major pelvic ganglion (MPG), and fewer neurons in the pelvic nerve. In the cavernous nerve, about 90% of TB-labeled efferent neurons were ND positive, and about 80% in the body of the MPG and pelvic nerve. Besides, 60-80% of TB-labeled efferent neurons projecting to the corpus cavernosum showed VIP immunoreactivity. VIP was colocalized with NOS in 70-80% of neurons. CONCLUSIONS: These findings suggest that most of the ND-positive nerves and terminals in the corpus cavernosum come from the MPG via the cavernous nerve and that NO plays an important role; it may act in combination with NO because most NOS-containing neurons simultaneously showed VIP immunoreactivity.

Animals↗
PubMed1997

[A case of myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA)-positive crescentic glomerulonephritis induced by propylthiouracil (PTU)].

We have experienced a case of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-related glomerulonephritis induced by propylthiouracil (PTU). A 45-year-old female had been treated with PTU for 4 years after the diagnosis of hyperthyroidism. She was referred to out hospital because of abrupt macroscopic hematuria and moderate proteinuria after several days of upper respiratory tract infection. On admission, her laboratory findings showed deterioration of renal function. Renal biopsy revealed crescentic glomerulonephritis without deposition of immune complexes. Her serology was found to be MPO-ANCA-positive and cytoplasmic-ANCA-negative. Based of these findings, we diagnosed idiopathic crescentic glomerulonephritis. Following the initiation of steroid pulse therapy, her urinary protein excretion and renal function gradually improved in parallel with a decrease in the MPO-ANCA titer. Although steroid therapy effectively responded to their renal function without the withdrawal of PTU, it seems that PTU may be closely associated with the development of (MPO-ANCA)-related glomerulonephritis in this case. Therefore, hyperthyroidism patients treated with PTU should be paced under vigilant observation by monitoring their urinalysis and serum creatinine level.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1997

[Tissue polypeptide antigen as a biological marker of malignant pleural mesothelioma].

To evaluate the role of tissue polypeptide antigen (TPA) as a biological marker of malignant pleural mesothelioma (MPM), we used immunohistochemical techniques to detect TPA in tumor cells, and we measured the content of TPA in serum from patients with MPM. In 14 of 16 patients with MPM, TPA was detected in the cytoplasm of tumor cells. Epithelial-type cells from 11 of 12 patients were stained positively (91.7%), and sarcomatous-type cells from 7 of 8 patients were stained positively (87.5%). Serum TPA levels were abnormally high in 7 of 9 patients. Two of three patients with stage-I disease had normal serum TPA levels, and all patients whose disease was at stage II or higher had abnormal serum TPA levels. Serum TPA levels increased as MPM progressed. These results suggest that the serum TPA level can be used as a biological marker of MPM.

Adult↗
PubMed1997

[Study on risk factors for central visual field loss in advanced open angle glaucoma].

53 eyes of 53 advanced open angle glaucoma (stage 5 of Aulhorn-Greve's classification) were studied regarding the risk factors for central visual field loss by the Cox proportional hazards model. The cases of foveal threshold under 20 dB were defined as central visual field loss group (9 eyes), and the cases over 20 dB were defined as no visual field loss group (44 eyes). The following clinical factors were statistically analyzed between the two groups: gender, age, family history of glaucoma, refraction, intraocular pressure, blood pressure, visual field measured by static perimetry, optic disc, retinal nerve fiber layer, treatment, and systemic disease. Foveal threshold, mean deviation, pattern standard deviation, corrected pattern standard deviation, and retinal nerve fiber layer defect showed significant difference between the two groups, and diastolic blood pressure and diastolic blood pressure minus intraocular pressure showed a tendency to be related. From the results obtained, intraocular pressure and these other clinical factors should be considered for the management of advanced open angle glaucoma patients.

Adult↗
PubMed1997

Technetium-99m(V)-DMSA and thallium-201 in brain tumor imaging: correlation with histology and malignant grade.

UNLABELLED: This study was performed to compare imaging ability between pentavalent 99mTc-DMSA and 201TlCl in primary and metastatic brain tumors and to evaluate the relationship between retention and histologic malignancy. METHODS: Patients with a brain tumor were selected by MRI and/or CT. Dynamic, early and delayed static SPECT images of the brain were obtained immediately, 30 min and 3 hr after intravenous administration of approximately 555 MBq 99mTc(V)-DMSA and 111 MBq 201Tl-Cl, respectively. Both studies were performed on separate days within a week. Uptake ratios, retention ratio and retention index were calculated and compared with tumor histology and malignancy grade. RESULTS: One-hundred six studies were performed on 100 patients and 118 lesions were demonstrated: 16 glioblastomas, 13 anaplastic astrocytomas (Grade III), 19 astrocytomas (Grade II), 29 meningiomas, 11 schwannomas and 14 metastases. Approximately 93% and 88%, respectively, of primary and metastatic brain tumors were demonstrated by 99mTc(V)-DMSA and 201TlCl. The early uptake ratios were closely related to the tumor vascularity, but had no statistically significant difference in the tumor histology or histologic malignancy on either radiopharmaceuticals. The delayed uptake ratio, retention ratio and retention index were higher in malignant tumors than benign ones on 99mTc(V)-DMSA, however, there was no statistically significant difference between benign and malignant tumors on 201TlCl. CONCLUSION: Technetium-99m(V)-DMSA washout from the tumor was highly dependent upon its histology and histologic malignancy. The delayed uptake ratio, retention ratio and retention index significantly reflected tumor histology and clearly distinguished between benign and malignant tumors with a statistically significant difference. There was no statistically significant difference in 201TlCl uptake or washout among the brain tumors. Technetium-99m-DMSA is superior to 201TlCl in imaging quality, sensitivity to brain tumors and specificity for differentiating benign tumors from malignant ones. These results could suggest the clinical utility of 99mTc(V)-DMSA in imaging primary and metastatic brain tumors and differentiating their histological malignancy grade noninvasively.

Brain Neoplasms↗
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↗
PubMed1997

[A survey of cognitive probability structure of risk of death by cause].

A person is believed to choose a health related behavioral alternative based on his/her perception of the health risk. This survey tried to clarify the structure of perceptions relating to risk of death, which seems to be the most fundamental among various health risks. A survey was performed in 1995 on 350 employees of two major companies. Subjects were shown two paired causes of death and asked which diseases caused deaths more frequently in the Japanese. Diseases included cancer, cerebral apoplexy, heart disease, traffic accident, tuberculosis, and lung cancer. The results obtained were as follows: 1. Generally, the order of perceived risk for each cause of death was similar to the real death numbers. 2. While traffic accidents tended to be overestimated for its risk, the risk perception for heart disease and cancer tended to be underestimated. 3. Young people tended to overestimate the risk of traffic accidents more than older people. Based on these results, it is suggested that people tend to overestimate current risks, and to underestimate future risks. This may contribute to the improvement of risk communication between health care providers and residents/patients.

Adult↗
PubMed1997

[A study on the prognosis of patients with asbestos pleurisy].

We investigated the outcome of patients with asbestos pleurisy. The mean follow-up period of 12 patients was 6.5 +/- 3.7 years. Recurrence occurred in 5 patients (41.7%). Six of the cases recurred contralateral to the original lesion, while one recurred ipsilaterally. The mean period from onset to recurrence was 2.8 +/- 2.8 years. Five of the cases ended in death, and the mean period from onset to death was 5.0 +/- 3.1 years. Two patients died from pneumonia, 2 died from respiratory failure due to progressive pleural fibrosis, and 1 died from lung cancer. One of the 2 patients with progressive pleural fibrosis had leukopenia. It has been reported that the majority of cases of asbestos pleurisy resolve spontaneously, with a good prognosis. However, because of the possible mortality associated with respiratory failure caused by progressive pleural fibrosis, it seems prudent to follow patients with asbestos pleurisy closely.

Aged↗
PubMed1996

Purification, characterization and subcellular localization of a type-1 ribosome-inactivating protein from the sarcocarp of Cucurbita pepo.

The flesh of the fruit of Cucurbita pepo contains a type-1 ribosome-inactivating protein (RIP), which we named pepocin. Pepocin was purified to apparent homogeneity by acid fractionation, ion-exchange chromatography and adsorption chromatography. The protein was found to have a molecular mass of 26 kDa and a pI of about 9.9. It does not contain glycosidic linkages. The protein inhibits protein synthesis in a rabbit-reticulocyte lysate with an IC50 (concentration causing 50% inhibition) of 15.4 pM, and depurinates 28S rRNA in the ribosomes of the lysate in a manner identical to that of ricin A-chain and other RIP. The enzyme is also active on wheat-germ ribosomes and on Escherichia coli ribosomes. The sequence of the N-terminal 20 amino acids of the protein reveals a close relationship to other RIP. Immunoelectron-microscopic localization of pepocin in the sarcocarp shows that the protein is predominantly localized in intercellular spaces. In addition, the immunolocalized signals are observed in leaf intercellular spaces.

Amino Acid Sequence↗
PubMed1996

Interplane Tunneling Magnetoresistance in a Layered Manganite Crystal

The current-perpendicular-to-plane magnetoresistance (CPP-MR) has been investigated for the layered manganite, La2-2xSr1+2xMn2O7 (x = 0.3), which is composed of the ferromagnetic-metallic MnO2 bilayers separated by nonmagnetic insulating block layers. The CPP-MR is extremely large (10(4) percent at 50 kilo-oersted) at temperatures near above the three-dimensional ordering temperature (Tc approximately 90 kelvin) because of the field-induced coherent motion between planes of the spin-polarized electrons. Below Tc, the interplane magnetic domain boundary on the insulating block layer serves as the charge-transport barrier, but it can be removed by a low saturation field, which gives rise to the low-field tunneling MR as large as 240 percent.

Journal Article↗