Biomedical subjects

H J Majima

Publications and source records attributed to H J Majima.

10 recordsLinked to original sources

PubMed2006

Irreversible morphological changes in leg bone following chronic gravitational unloading of growing rats.

Effects of gravitational unloading or loading on the growth and development of hindlimb bones were studied in rats. Male Wistar rats were hindlimb-unloaded or loaded at 2-G from the postnatal day 4 to month 3. The morphology and mineral content of tibia and fibula, as well as the mobility of ankle joints, were measured at the end of 3-month suspension or loading, and 1, 2, and 3 months after ambulation recovery. Growth-related increases of bone weight and mineral density were inhibited by unloading. But they were gradually recovered toward the control levels, even though they were still less than those in the age-matched controls after 3 months. None of the parameters were influenced by 2-G loading. However, here we report that chronic unloading causes abnormal morphological development in hindlimb bone of growing rats. Irreversible external bend of the shaft and rotation of the distal end of tibia, which limit the dorsiflexion of ankle joints, were induced following chronic gravitational unloading during developing period. It is also suggested that such phenomena are caused by the abnormal mechanical forces imposed by muscle utilization with altered patterns. The activity of ankle dorsiflexor was increased and that of plantarflexor was inhibited during unloading.

Animals↗

PubMed2006

Pleomorphic adenoma presenting low T2 signal-intensity on magnetic resonance imaging.

We report an unusual case of pleomorphic adenoma of the submandibular gland in a 48-year-old female. The present case appeared as a relatively homogeneous, low to intermediate signal-intensity on the T(2) weighted magnetic resonance (MR) images. To our knowledge, the MR feature of low T(2) signal-intensity of pleomorphic adenoma has not been reported in the literature.

Adenoma, Pleomorphic↗

PubMed2005

Thallium-201 chloride (Tl-201) accumulation and Na+/K+-ATPase expression in tumours of the head and neck.

OBJECTIVES: The purpose of this report was to evaluate the relationship between the tumour retention index of thallium-201 chloride (Tl-201) scintigraphy and the Na+/K+-ATPase expression in tumours of the head and neck. METHODS: Tl-201 scintigraphy was performed in 146 patients (129 with malignant tumours, ten with benign tumours and seven with inflammation). The tumour retention index was obtained from the early and delayed dynamic Tl-201 scans. The Na+/K+-ATPase expression was evaluated immunohistochemically in 61 of 129 patients with malignant tumour. Furthermore, another 22 patients with benign tumour were evaluated immunohistochemically as a benign control. Comparison of the correlations between the grade of histopathological differentiation of tumour, the tumour retention index of Tl-201 scintigraphy and the Na+/K+-ATPase expression was performed. RESULTS: The grade of histopathological differentiation of tumour, the tumour retention index of Tl-201 scintigraphy and the expression of Na+/K+-ATPase showed a good correlation indicating that Na+/K+-ATPase plays an important role in transportation for Tl-201 to go through the tumour cell membrane. CONCLUSIONS: Na+/K+-ATPase is one of the most important factors for Tl-201 accumulation in tumour.

Adenocarcinoma↗

PubMed2005

Scintigraphy for interpretation of malignant tumours of the head and neck: comparison of technetium-99m-hexakis-2-methoxyisobutylisonitrile (Tc-MIBI) and thallium-201-chloride (Tl-201).

OBJECTIVES: The purpose of this study was to compare the usefulness of technetium-99m-hexakis-2-methoxyisobutylisonitrile (99Tc(m)-MIBI) and thallium-201-chloride (Tl-201) as scintigraphic agents. METHODS: Dynamic and static scintigraphic imaging with 99Tc(m)-MIBI and Tl-201 were performed on patients with a variety of malignant and benign tumours. Factors of the grade of the static scan, the blood flow index, the early and delayed retention indexes, and the tumour retention index were obtained from the scintigraphy. In addition to these factors, the grade of tissue differentiation and tumour size were evaluated to clarify the difference between 99Tc(m)-MIBI and Tl-201 for the diagnosis of malignant tumours of the head and neck. RESULTS: 99Tc(m)-MIBI accumulation depended upon the blood flow index in the early static scan, but this accumulation did not correlate with tumour size. The accumulation in most subjects decreased in the delayed static scan, and the tumour retention index had a tendency to decrease with the grade of tissue differentiation. Tl-201 accumulation depended upon the blood flow index in the early static scan similar to 99Tc(m)-MIBI, and the accumulation correlated with tumour size, unlike 99Tc(m)-MIBI. The tumour retention index had a tendency to increase with the grade of tissue differentiation. Thus, the tumour retention indexes showed opposite behaviours between 99Tc(m)-MIBI and Tl-201, but they both accurately determined tumour malignancy. CONCLUSIONS: There was no major difference between 99Tc(m)-MIBI and Tl-201scintigraphy with respect to accuracy of diagnosis of malignant tumours of the head and neck. However, 99Tc(m)-MIBI was superior to Tl-201 for small-size tumours and Tl-201 was useful for large-size tumours.

Adenocarcinoma↗

PubMed2005

Expression of permeability-glycoprotein (P-gp) and uptake of technetium-99m-hexakis-2-methoxy-isobutyl-isonitrile (99Tcm-MIBI) in malignant tumour of the head and neck.

OBJECTIVES: The purpose of this study is to estimate the role of permeability-glycoprotein (P-gp) in the technetium-99m-hexakis-2-methoxy-isobutyl-isonitrile (99Tc(m)-MIBI) scintigraphy. METHODS: 71 patients with squamous cell carcinoma (39 patients with well differentiated, 19 with moderately differentiated and 13 with poorly differentiated tumour) were examined. Eighteen of these patients underwent 99Tc(m)-MIBI scintigraphy (early and delayed scans). The tumour retention index, obtained from the ratio of the accumulation of the delayed scan to that of the early scan, was divided into three groups. The immunohistochemical evaluation of P-gp expression was performed in all 71 patients. Levels of the P-gp expression were classified into three grades (score 0, 1 and 2). Correlations among the tumour retention index, the P-gp expression and the tumour tissue differentiation were evaluated. RESULTS: 17 of 18 patients showed a decreasing of the tumour retention index ranging from 0.70 to 0.93 (mean+/-SD=0.850+/-0.071). The tumour retention index showed a statistical correlation with the P-gp expression and the tumour tissue differentiation (chi-squared=7.802>7.779, P=0.10 and 16.835>14.860, P=0.005, respectively). Moreover, there was a statistical correlation between the P-gp expression and the tumour tissue differentiation (chi-squared=14.863>14.860, P=0.005). CONCLUSION: There is a possibility that the P-gp expression is high in the high-grade malignant tumours and P-gp causes the decrease of tumour retention index.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

A trial for histopathological subclassification of papillary cystadenoma lymphomatosum by 99Tcm-pertechnetate in a patient with multiple bilateral lesions of the parotid glands.

OBJECTIVES: The purpose of this report was to evaluate the possibility of subclassification of papillary cystadenoma lymphomatosum (PCL) with 99Tc(m)-pertechnetate. METHODS: A patient with multiple bilateral PCLs in the parotid glands was examined by using 99Tc(m)-pertechnetate. RESULTS: All PCLs of the present case, which were diagnosed as the subtype-II histopathologically, showed similar radioactive indexes in scintigraphy (the mean radioactive index = 3.62), although tumours were different in size. The mean radioactive index corresponded well with that from four cases of subtype-II of our previous report (the mean radioactive index = 3.84). CONCLUSIONS: The results of the present report suggest a possibility of histopathological subclassification of PCLs into subtypes by 99Tc(m)-pertechnetate scintigraphy.

Adenolymphoma↗

PubMed2004

Increased expression of humanin peptide in diffuse-type pigmented villonodular synovitis: implication of its mitochondrial abnormality.

OBJECTIVES: To define the pathogenesis of pigmented villonodular synovitis (PVNS), by searching for highly expressed genes in primary synovial cells from patients with PVNS. METHODS: A combination of subtraction cloning and Southern colony hybridisation was used to detect highly expressed genes in PVNS in comparison with rheumatoid synovial cells. Northern hybridisation was performed to confirm the differential expression of the humanin gene in PVNS. Expression of the humanin peptide was analysed by western blotting and immunohistochemistry. Electron microscopic immunohistochemistry was performed to investigate the distribution of this peptide within the cell. RESULTS: 68 highly expressed genes were identified in PVNS. Humanin genes were strongly expressed in diffuse-type PVNS, but were barely detected in nodular-type PVNS, rheumatoid arthritis, or osteoarthritis. Humanin peptide was identified in synovium from diffuse-type PVNS, and most of the positive cells were distributed in the deep layer of the synovial tissue. Double staining with anti-humanin and anti-heat shock protein 60 showed that humanin was expressed mainly in mitochondria. Electron microscopy disclosed immunolocalisation of this peptide, predominantly around dense iron deposits within the siderosome. CONCLUSIONS: Increased expression of the humanin peptide in mitochondria and siderosomes is characteristic of synovial cells from diffuse-type PVNS. Humanin is an anti-apoptotic peptide which is encoded in the mitochondrial genome. Present findings suggest that mitochondrial dysfunction may be the principal factor in pathogenesis of diffuse-type PVNS and that humanin peptide may play a part in the neoplastic process in this form of PVNS.

Arthritis, Rheumatoid↗

PubMed2001

Overexpression of mitochondrial manganese superoxide dismutase protects against radiation-induced cell death in the human hepatocellular carcinoma cell line HLE.

We investigated the potential role of mitochondrial manganese superoxide dismutase (Mn-SOD) in protective activity against irradiation by analyzing cell viability by a colony formation assay and by detecting apoptosis in stably human Mn-SOD gene-transfected HLE, a hepatocellular carcinoma cell line. We found that overexpression of Mn-SOD reduced the levels of reactive oxygen species in the mitochondria and intracellular phospholipid peroxidation product (4-hydroxy-2-nonenal) and prevented cell death. The production of intracellular nitric oxide after irradiation was not changed by Mn-SOD overexpression. The results suggested that Mn-SOD might play an important role in protecting cells against radiation-induced cell death by controlling the generation of mitochondrial reactive oxygen species and intracellular lipid peroxidation.

Apoptosis↗

PubMed1998

Prevention of mitochondrial injury by manganese superoxide dismutase reveals a primary mechanism for alkaline-induced cell death.

Alkalosis is a clinical complication resulting from various pathological and physiological conditions. Although it is well established that reducing the cellular proton concentration is lethal, the mechanism leading to cell death is unknown. Mitochondrial respiration generates a proton gradient and superoxide radicals, suggesting a possible link between oxidative stress, mitochondrial integrity, and alkaline-induced cell death. Manganese superoxide dismutase removes superoxide radicals in mitochondria, and thus protects mitochondria from oxidative injury. Cells cultured under alkaline conditions were found to exhibit elevated levels of mitochondrial membrane potential, reactive oxygen species, and calcium which was accompanied by mitochondrial damage, DNA fragmentation, and cell death. Overexpression of manganese superoxide dismutase reduced the levels of intracellular reactive oxygen species and calcium, restored mitochondrial transmembrane potential, and prevented cell death. The results suggest that mitochondria are the primary target for alkaline-induced cell death and that free radical generation is an important and early event conveying cell death signals under alkaline conditions.

Animals↗

PubMedDate not supplied

Accumulation of mutant p53 and hsp72 by heat treatment, and their association in a human glioblastoma cell line.

The cellular content of mutant p53 and hsp72 proteins following gamma-ray irradiation, UV irradiation, and heat treatment was studied in A-7 cells, a human glioblastoma cell line. A-7 was found to contain a mutant p53 gene in which the arginine codon at position 175 was substituted by a histidine codon. Although the p53 gene was mutant, the phenotype of the p53 protein appeared wild-type since the cellular content of the p53 protein was limited under normal culturing conditions. The quantity of mutant p53 and hsp72 proteins in A-7 was increased by heat treatment as well as gamma-ray and UV irradiation. Furthermore, the mutant p53 protein was coimmunoprecipitated with anti-hsp72/hsc73 antibody. Additionally, hsp72 and hsc73 were coimmunoprecipitated with anti-p53 antibody. These results suggest that in A-7, p53 protein accumulation may be caused as a result of response to stressors, such as gamma-ray, UV and heat and that mutant p53 protein and hsp72/hsc73 may manage biological functions cooperatively after gamma-ray, UV and also heat treatments.

Gamma Rays↗