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Biomedical subjects

M Ohishi

Publications and source records attributed to M Ohishi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Immunohistochemical evaluation of PCNA and Ki-67 in ameloblastoma.

Thirty-two ameloblastoma tissues were immunohistochemically studied using monoclonal anti-proliferating cell nuclear antigen (PCNA) and anti-Ki-67 antibodies. Positive cells were evaluated and analyzed in relation to the WHO classification, cytological pattern of the outer layer cell, clinical appearance, tumor location, radiographic appearance and patient's age. In regard to the cytological pattern of the outer layer cells, the basal cell type had significantly higher PCNA and Ki-67 (P<0.05) labeling indices than the cuboidal cell type. The solid type had significantly higher PCNA and Ki-67 (P<0.05) labeling indices than the cystic and the mixed type. The labeling index of the younger patient was found to be the lowest, the middle age was in the middle and the older patient was the highest. These results indicated that the proliferating activities of ameloblastomas are quite variable, and the evaluations of Ki-67 and PCNA seem to be good indicators to assess the proliferating activity of each type of ameloblastomas.

Adolescent↗
PubMed2001

Two relatively distinct patterns of ameloblastoma: an anti-apoptotic proliferating site in the outer layer (periphery) and a pro-apoptotic differentiating site in the inner layer (centre).

AIMS: This study was performed to determine the apoptotic behaviour of ameloblastomas by analysing the role of bcl-2 family proteins in ameloblastomas and the location of terminally apoptotic cells in the ameloblastoma epithelial tissues. METHODS AND RESULTS: For immunohistochemistry, tissue sections of 32 patients were treated with an antigen-retrieval METHOD: Primary antibodies against the apoptosis-related proteins, bcl-2, bcl-X, bax, and bak were applied. Besides immunohistochemistry, Western blotting and TUNEL were also performed. Most of the outer layer cells were predominantly stained by the bcl-2 antibody, while most of the inner layer cells were stained by antibodies against the apoptosis-modulating proteins, bax and bak. Among the bcl-2 family, bcl-2 was the most ubiquitously expressed protein in ameloblastomas, while bcl-X was expressed in the greatest concentrations. The major bcl-X protein was bcl-XL. Some of the inner layer cells entered the terminal apoptotic stage, which were revealed by TUNEL. The acanthomatous areas over-expressed the apoptosis-modulating proteins, especially bak. CONCLUSIONS: Ameloblastoma has much more apoptosis-inhibiting protein than the apoptosis-modulating protein. Ameloblastoma has two relatively distinct patterns, an anti-apoptotic proliferating site in the outer layer (periphery) and a pro-apoptotic differentiating site in the inner layer (centre). The acanthomatous area, which was stained strongly by bak antibody and contained numerous terminally apoptotic cells, was considered as the differentiated area.

Adolescent↗
PubMed2001

Growth characteristics of ameloblastoma involving the inferior alveolar nerve: a clinical and histopathologic study.

OBJECTIVE: Growth characteristics of ameloblastomas involving the inferior alveolar nerve were examined to determine the most appropriate surgical management of the nerve at the time of the surgical procedure. STUDY DESIGN: Clinical and histopathologic examinations were performed on 22 resected mandibles in which the inferior alveolar nerve was lying adjacent to, or contained within, the tumor. RESULTS: Patterns of tumor involvement of the nerve bundle were evaluated with respect to the presence of bone (11 patients) or connective tissue wall (7 patients) between the tumor and the nerve bundle, and tumor infiltration of perineural connective tissue (4 patients). Neither invasion into the nerve sheath nor invasion into the nerve itself by the ameloblastoma was detected. Tumor infiltration of the tissue surrounding the nerve was identified for the multicystic and solid types but not for the unicystic type. Presence of bone or connective tissue wall between the tumor and the nerve bundle was dominant in the unicystic and plexiform ameloblastomas, whereas tumor infiltration of the perineural tissue was frequently observed in ameloblastomas with the follicular pattern. CONCLUSION: The preservation of the inferior alveolar nerve may be possible in the management of the unicystic type of ameloblastoma. However, a more radical approach is necessary for treatment of multicystic or solid tumors, especially those exhibiting a follicular pattern.

Adolescent↗
PubMed2001

The Saccharomyces cerevisiae small GTPase, Gsp1p/Ran, is involved in 3' processing of 7S-to-5.8S rRNA and in degradation of the excised 5'-A0 fragment of 35S pre-rRNA, both of which are carried out by the exosome.

Dis3p, a subunit of the exosome, interacts directly with Ran. To clarify the relationship between the exosome and the RanGTPase cycle, a series of temperature-sensitive Saccharomyces cerevisiae dis3 mutants were isolated and their 5.8S rRNA processing was compared with processing in strains with mutations in a S. cerevisiae Ran homologue, Gsp1p. In both dis3 and gsp1 mutants, 3' processing of 7S-to-5.8S rRNA was blocked at three identical sites in an allele-specific manner. In contrast, the 5' end of 5.8S rRNA was terminated normally in gsp1 and in dis3. Inhibition of 5.8S rRNA maturation in gsp1 was rescued by overexpression of nuclear exosome components Dis3p, Rrp4p, and Mtr4p, but not by a cytoplasmic exosome component, Ski2p. Furthermore, gsp1 and dis3 accumulated the 5'-A0 fragment of 35S pre-rRNA, which is also degraded by the exosome, and the level of 27S rRNA was reduced. Neither 5.8S rRNA intermediates nor 5'-A0 fragments were observed in mutants defective in the nucleocytoplasmic transport, indicating that Gsp1p regulates rRNA processing through Dis3p, independent of nucleocytoplasmic transport.

Active Transport, Cell Nucleus↗
PubMed2001

Immunohistochemical localization of osteopontin in human pulp stones.

The organic matrix component of human pulp stones was investigated by immunohistochemistry. Two pulp stones were extracted from the upper molar teeth of two patients suffering from irreversible pulpitis. Both were formed in the center of the pulp cavity and located apart from the dentin walls. After demineralization, serial sections of the stones were prepared and subjected to immunohistochemical procedures using specific antibodies to type I collagen and noncollagenous proteins (osteopontin, osteonectin, and osteocalcin), which are reported to be involved in calcified matrix formation. Type I collagen was localized evenly in the stones, indicating that it is a major matrix component of pulp stones. Strong immunostaining of osteopontin appeared in the peripheral area of the stones, whereas osteonectin and osteocalcin were not detected. We previously reported that dental pulp cells produced osteopontin in vitro. Osteopontin has been commonly found in other pathological calcification, such as urinary stones, atherosclerotic plaques, and dental calculus. Taken together, the present findings suggest that osteopontin produced by dental pulp cells is possibly associated with calcification of the pulp stone matrix.

Antibodies↗
PubMed2001

Immunodominant region of Actinobacillus actinomycetemcomitans 40-kilodalton heat shock protein in patients with rheumatoid arthritis.

Bacterial heat shock proteins have been implicated in the pathogenesis of several diseases, and the immunological relationship between rheumatoid arthritis (RA) and Escherichia coli DnaJ has been reported. Since there are similarities in the tissue destruction process of RA and periodontitis, we examined the reactivities of antibodies in sera from RA patients to the DnaJ protein from Actinobacillus actinomycetemcomitans. An enzyme-linked immunosorbent assay showed that IgG titers to the N-terminal conservative region of the DnaJ are significantly higher in RA patients compared with the healthy controls (p < 0.05). Furthermore, we examined IgG titers of disease controls to determine the specificity of the immune responses to this region in RA patients. The difference between RA and infectious disease patients was also significant (p < 0.05). These results suggest that the N-terminal region of DnaJ from A. actinomycetemcomitans may contribute to the etiologic analysis of RA.

Adult↗
PubMed2001

Characteristics of an ammonia-oxidizing bacterium with a plasmid isolated from alkaline soils and its phylogenetic relationship.

An ammonia-oxidizing bacterium, strain TCH716, was isolated from alkaline soil at Harbin city, China. The cells of strain TCH716 are lobate (0.8-1.5 x 1.0-2.0 microm), gram-negative, obligately aerobic, and nonmotile. Colonies (1-2 mm in diameter) on gellan gum plate culture are reddish, circular, and smooth. The G + C content of DNA is 54.78 mol%. Its percentage of 16S rRNA gene sequence similarity (%) to Nitrosolobus multiformis ATCC 25196T (type strain) is 98.56%. This bacterium has an optimal growth temperature and pH at 30 degrees C and 8.0-8.5, respectively. The concentration of ammonium sulfate in the HEPES medium for optimum growth of this bacterium is 38 mM. Strain TCH716 was found to have a plasmid (approximately 6.5 kbp) that possessed a plasmid-linked gene for sulfonamide resistance. Phosphoglycerate kinase, RubisCO and PEPC were found to possess high specific activities compared to the activities of these enzymes in strain ATCC 25978T. In identification of strain TCH716, both morphological characteristics (compartmentalized cells) and the phylogenetic relationship based on 16S rRNA gene sequence are important. Based on results obtained, strain TCH716 belongs to the genus Nitrosolobus, and designated as Nitrosolobus sp. TCH716.

Journal Article↗
PubMed2001

Effects of antihypertensive drugs and gene variants in the renin-angiotensin system.

Many genes and environmental factors are involved in the pathogenesis of hypertension, but the exact cause of essential hypertension has not yet been clarified. Gene polymorphism of the renin-angiotensin system (RAS) is one of the candidates. In the current study, we examined whether there was a correlation between the gene polymorphisms in RAS and either the choice of antihypertensive drugs or their efficacy. Subjects with essential hypertension (n=299) were recruited from among the outpatients of Osaka University Hospital and provided their informed consent for genetic analysis. Physicians freely chose the antihypertensive drugs and adjusted its dose until the patient's blood pressure was well controlled. The efficacy of each antihypertensive drug was estimated using the following formula: ABP=BP 1 (before treatment) - BP 2 (after treatment)/BP 1 x 100 (%). Gene variants in RAS were determined using PCR or PCR-RFLP (restriction fragment of polymorphism). The gene polymorphisms of RAS were not associated with delta SBP or ADBP. However, the mean ASBP in subjects with a deletion homozygote of the angiotensin converting enzyme gene (ACE/DD) was significantly lower (p<0.05) than that in patients with an insertion I allele of the ACE gene. The gene polymorphisms of RAS did not significantly affect the choice of antihypertensive drugs. Even though gene polymorphism in the renin angiotensin system was not a major factor in the antihypertensive therapy, the determination of genotype might be of help in the management of essential hypertension.

Antihypertensive Agents↗
PubMed2001

Arg-gingipain is responsible for the degradation of cell adhesion molecules of human gingival fibroblasts and their death induced by Porphyromonas gingivalis.

Arg-gingipain (Rgp) and Lys-gingipain (Kgp) are two major cysteine proteinases produced by the oral anaerobic bacterium Porphyromonas gingivalis, which has been shown to act as major pathogen in the development and progression of periodontal diseases. These enzymes are also important for this organism to proliferate and survive in periodontal pockets. Here we show that Rgp is responsible for the disruption of fibronectin-integrin interactions in human gingival fibroblasts by P. gingivalis. Fibroblasts incubated with the culture supernatant of P. gingivalis showed a time-dependent loss of the adhesion activity. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting revealed that fibronectin and integrin subunits alpha2, beta1 and beta3 in the fibroblast culture largely disappeared with the treatment. The detached cells became committed to death by disruption of contacts between adhesion molecules. In contrast, the culture supernatants from the Rgp-deficient mutants produced no significant changes in either cell adhesion or viability. Prior treatment of the culture supernatant of P. gingivalis with an Rgp inhibitor, but not a Kgp inhibitor, strongly inhibited the detachment of fibroblasts followed by cell death. These results suggest that Rgp disrupts the integrin-fibronectin interactions in fibroblasts, thereby contributing to the damage of periodontal tissues in periodontal diseases caused by P. gingivalis.

Adhesins, Bacterial↗
PubMed2001

[A case of severe systemic edema in an elderly hypertensive patient with systemic lupus erythematodes during long-term treatment with anti-hypertensive drugs].

A 71-year-old woman receiving both angiotensin II receptor antagonist and calcium antagonist suffered severe systemic edema. She had been treated for essential hypertension with amlodipine for 2 years and candesartan for 3 months, and systemic lupus erythematodes (SLE) with steroids. During treatment, severe systemic edema appeared, mainly on her face, arms, and legs. At first, we suspected drug-induced edema by candesartan, so it was halted, but the edema still continued. We then considered amlodipine to be the culprit, and finally, the severe systemic edema disappeared after cessation of amlodipine. To control her blood pressure, we recommended candesartan, but 3 months late she suffered severe systemic edema again, thus the causative we drugs of her edema were thought to be both amlodipine and candesartan. Edema is a common symptom in elderly patients and we frequently observe drug-induced edema. In this case, there was underlying acceleration of blood vessel permeability induced by SLE and steroids and moreover, vasodilatation by candesartan and/or amlodipine further accelerated blood vessel permeability, and thus might have caused severe edema. It is very difficult to determine the cause of edema, especially in elderly patients, but we should consider not only one but also two or more drugs as being involved in drug-induced edema.

Aged↗
PubMed2001

Reversibility of n-3 fatty acid deficiency-induced alterations of learning behavior in the rat: level of n-6 fatty acids as another critical factor.

Rats fed a semipurified diet supplemented with 3% (w/w) safflower oil [Saf, n-3 fatty acid deficient, high linoleic acid (18:2n-6)] through two generations exhibit decreased correct response ratios in a brightness-discrimination learning test compared with rats fed 3% perilla oil [Per, high alpha-linolenic acid (18:3n-3)]. This is associated with a decreased DHA (22:6n-3)-to-arachidonic acid (20:4n-6) ratio in brain lipids. In the first set of experiments, dietary oil was shifted from Saf to a mixture of 2.4% safflower oil plus 0.6% DHA after weaning (Saf-DHA), but all parameters measured in the learning test were essentially unchanged. Brain 22:6n-3 content of the Saf-DHA group reached that of the Per group but the levels of 20:4n-6 and docosatetraenoic acid (22:4n-6) did not decrease to those of the Per group at the start of the test. In the second set of experiments, dietary oil was shifted to a mixture of 0.6% safflower oil plus 1.2% oleic acid (OA) plus 1.2% DHA (Saf-OA-DHA group) with 18:2n-6 content comparable to that of the Per group. The Saf-OA-DHA group exhibited a learning performance similar to that of the Per group; brain 22:6n-3, 20:4n-6, and 22:4n-6 contents were also comparable to those of the Per group. These results indicate that the altered learning behavior associated with a long-term n-3 fatty acid deficiency is reversed by supplementing 22:6n-3 after weaning, when the levels of competing n-6 fatty acids in the diet and brain lipids are limited.

Aging↗
PubMed2000

Dietary n-3 fatty acid deficiency decreases nerve growth factor content in rat hippocampus.

Dietary deprivation of alpha-linolenic acid (n-3) through two generations has been shown to lower performance in an operant-type brightness-discrimination learning test in rats. Here, we examined a possible correlation between nerve growth factor (NGF) content and n-3 fatty acid status in the brain. Female rats were fed a semipurified diet supplemented with safflower oil (n-3 fatty acid-deficient) and their offsprings were fed a diet supplemented with either 3% safflower oil (Saf group) or a mixture of 2.4% safflower oil plus 0.6% ethyl eicosapentaenoate (Saf+EPA group) after weaning. The brain docosahexaenoic acid (22:6n-3, DHA) content in the Saf group was less than half of that in the Per group fed a diet supplemented with 3% perilla oil (n-3 fatty acid-sufficient) throughout the duration of the experiment. The DHA level of the Saf+EPA group was restored to the level of the Per group. However, the NGF contents in the hippocampus of the Saf and Saf+EPA groups were half that of the Per group. In the piriform cortex, the NGF content tended to be higher in the Saf and Saf+EPA groups than in the Per group. These results indicate that dietary n-3 fatty acid deficiency and restoration affect NGF levels differently among different brain regions.

Animals↗
PubMed2000

Effect of n-3 fatty acid deficiency on fatty acid composition and metabolism of aminophospholipids in rat brain synaptosomes.

Docosahexaenoic acid (DHA, 22:6n-3) is one of the major polyunsaturated fatty acids esterified predominantly in aminophospholipids such as ethanolamine glycerophospholipid (EtnGpl) and serine glycerophospholipid (SerGpl) in the brain. Synaptosomes prepared from rats fed an n-3 fatty acid-deficient safflower oil (Saf) diet had significantly decreased 22:6n-3 content with a compensatory increased 22:5n-6 content when compared with rats fed an n-3 fatty acid-sufficient perilla oil (Per) diet. When the Saf group was shifted to a diet supplemented with safflower oil plus 22:6n-3 (Saf + DHA) after weaning, 22:6n-3 content was found to be restored to the level of the Per group. The uptake of [3H]ethanolamine and its conversion to [3H]EtnGpl did not differ significantly among the three dietary groups, whereas the formation of [3H]lysoEtnGpl from [3H]ethanolamine was significantly lower in the Saf group than in the other groups. The uptake of [3H]serine, its incorporation into [3H]SerGpl, and the conversion into [3H]EtnGpl by decarboxylation of [3H]SerGpl did not differ among the three dietary groups. The observed decrease in lysoEtnGpl formation associated with a reduction of 22:6n-3 content in rat brain synaptosomes by n-3 fatty acid deprivation may provide a clue to reveal biochemical bases for the dietary fatty acids-behavior link.

Animals↗
PubMed2000

Differential expression of cytokeratin after orthotopic implantation of newly established human tongue cancer cell lines of defined metastatic ability.

Two human tongue squamous cell carcinoma cell lines, SQUU-A and SQUU-B, were established from the same patient. Cervical lymph node metastasis was detected in the mice orthotopically implanted with SQUU-B (86.7%, 13/15), but not in those with SQUU-A (0/13). Histologically, SQUU-B showed invasive growth and intravasation in the tongue, whereas SQUU-A simply demonstrated expansive growth without intravasation. By Western blot analysis, nonmetastatic clone SQUU-A expressed cytokeratin (CK)13/4, 14, 16/6, 18/8, and 19, whereas a high metastatic clone SQUU-B expressed CK18/8 and 19. The reverse transcription-polymerase chain reaction technique showed that CK13/4 mRNA was expressed in both cell lines, but CK14 and 16 mRNA was expressed only in SQUU-A. CK13 was immunohistochemically expressed in both SQUU-A and SQUU-B transplanted into the tongues of nude mice; CK14 and 16 were detected in SQUU-A of the tongues, but not in SQUU-B. As seen in SQUU-B cell line, SQUU-B of the cervical lymph node metastasis did not exhibit CK13, 14, or 16. These results suggest that the loss or down-regulation of CK13, 14, or 16 is related to the invasive and metastatic ability of cancer. The cytoskeletal system is thus considered to be closely related to the malignant phenotype.

Animals↗
PubMed2000

Telomerase activity in oral and maxillofacial tumors.

Telomerase activity was measured in biopsy specimens as well as surgically resected tissues of 39 oral squamous cell carcinomas (SCCs), 22 oral leukoplakias, 13 normal oral mucosas, 12 malignant salivary gland tumors, 10 benign salivary tumors and five normal salivary gland tissues adjacent to tumors using a polymerase chain reaction (PCR)-based telomerase assay. Telomerase activity was detectable in 38.5% (5/13) of normal oral mucosa samples, 54.5% (12/22) of leukoplakia samples, 82.1% (32/39) of oral SCC samples, 83.3% (10/12) of malignant salivary gland tumor samples and 0% (0/10, 0/5) of benign salivary gland tumor and normal salivary gland samples. High-level enzyme activities were seen in 20% (3/15) of mild dysplasia specimens, 50% (2/4) of moderate-severe dysplasia specimens, 48.7% (19/39) of oral SCC tissue specimens, and no high activity was seen in the normal mucosa and hyperkeratosis specimens (P for trend, <0.001). We also analyzed the proliferative activity of dysplastic leukoplakia, oral SCC, and salivary gland tumor specimens using Ki-67 immunohistochemistry. The Ki-67 labeling indices (LI) were significantly higher in dysplastic leukoplakia and oral SCC with high telomerase activity than in dysplastic leukoplakias and oral SCC with low and negative telomerase activity (P<0.01 and P<0.05). These results indicate that telomerase activity has some correlation with the progression of multistep oral carcinogenesis with the cellular proliferation, and also indicate that telomerase may be a specific marker used to distinguish malignant salivary gland tumors from their benign counterparts.

Biomarkers, Tumor↗
PubMed2000

Ursodeoxycholic acid reduces expression of heat shock proteins in primary biliary cirrhosis.

BACKGROUND: To identify injured cells in the liver of patients with primary biliary cirrhosis (PBC) and to determine the effects of ursodeoxycholic acid (UDCA) on these cells, we examined the cellular expression of heat shock proteins (HSPs) in PBC both before and after treatment with UDCA. METHODS: Expression of HSP70 and ubiquitin in PBC livers (n=34) was evaluated immunohistochemically as well as by immunoblot analysis, and compared with chronic viral hepatitis type C (n= 9), primary sclerosing cholangitis (n=8), and controls (n=7). RESULTS: Immunoblot analysis demonstrated a marked expression of HSP70 and ubiquitin in PBC. Immunohistochemical staining for both HSP70 and ubiquitin was observed to be strong in biliary epithelial cells (BECs) and moderate in both hepatocytes and arteries in PBC. Cellular labelling rates for HSP70 and ubiquitin of bile ducts in PBC were significantly higher (p<0.01) than those in chronic viral hepatitis type C, primary sclerosing cholangitis, or controls. The labelling rates for HSP70 and ubiquitin in bile ducts and in hepatocytes were significantly decreased (p<0.01) after treatment with UDCA in PBC. CONCLUSIONS: The present data suggest that BECs and hepatocytes significantly express HSPs even in the early stages of PBC, and that UDCA treatment significantly improves their condition. The immunohistochemical evaluation of HSPs is a valid and sensitive means to identify injured cells in PBC.

Adult↗