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Biomedical subjects

M Ohishi

Publications and source records attributed to M Ohishi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Computed tomography and ultrasonography of metastatic cervical lymph nodes in oral squamous cell carcinoma.

OBJECTIVES: To define criteria for CT and US in differentiating cervical lymph node metastases in oral squamous cell carcinoma (SCC). MATERIALS AND METHODS: CT and/or US of 230 metastatic lymph nodes and 228 benign lymph nodes in 147 patients with oral SCC were retrospectively evaluated. The CT and US findings of each lymph node were compared with the histopathological findings. A metastasis was defined on CT as a lymph node with rim or heterogeneous enhancement, or measuring 10 mm or more in the short axis, regardless of enhancement pattern, and on US as having definite internal echoes, regardless of size, or without definite internal or hilar echoes, but measuring 10 mm or more in the short axis. A lymph node with hilar echoes or a ratio of the long to short axis (L/S ratio) of 3.5 or more was considered benign. A lymph node failing to comform to any of these categories was termed questionable. RESULTS: The positive predictive value (PPV) for CT was 90.8% and the negative predictive value (NPV) was 70.4%. However, 65.7% of all lymph nodes could not be classified as either metastastic or benign. PPV for US was 96.5% and NPV was 88.1%. 25.5% of all lymph nodes could not be classified as either metastatic or benign. CONCLUSIONS: Despite limitations in detecting metastases, by including a third category 'questionable' our criteria appear clinically more useful than other current methods based on two groups only.

Adult↗
PubMed2000

Deletion polymorphism of angiotensin-converting enzyme gene is associated with postprandial hyperglycaemia in individuals undergoing general check-up.

1. Deletion polymorphism, DD, of the angiotensin-converting enzyme (ACE) gene is reported to be related to cardiovascular disease, which is frequently based on insulin resistance. 2. To clarify the relationship between the ACE genotype DD and plasma glucose increases after an oral glucose load, we performed 75 g oral glucose tolerance test (OGTT) in 301 nondiabetic men (age range 30-60 years) undergoing general check-up. 3. Insertion/deletion (I/D) polymorphism of the ACE gene was explored using a polymerase chain reaction. The frequency of the II, ID and DD genotypes was 0.43, 0.43 and 0.14, respectively. 4. There were no differences in baseline clinical characteristics between subjects with each ACE genotype. 5. The mean (+/- SEM) plasma glucose level at 60 min of the OGTT was significantly higher in subjects with the DD genotype (170.8 +/- 6.9 mg/dL) than in subjects with either the II or ID genotype (mean value for two groups 156.6 +/- 2.7 mg/dL; P < 0.05). Moreover, the mean percentage change of plasma glucose after 60 min of the OGTT, a marker of plasma glucose increase, was significantly higher in individuals with the DD genotype than in individuals with either the II or ID genotypes. 6. In contrast, the mean fasting plasma glucose level, the plasma glucose level at 120 min, the glucose response area and the fasting insulin level were not different between individuals with the DD genotype and individuals with other genotypes. 7. In conclusion, subjects with the DD genotype showed transiently higher levels of plasma glucose after an oral glucose load than subjects with other genotypes. Further studies are required to determine whether the association between ACE genotype and postprandial hyperglycaemia influences the incidence of cardiovascular disease and diabetes mellitus.

Adult↗
PubMed2000

Incidence of human papillomavirus 16 and 18 infection and p53 mutation in patients with oral squamous cell carcinoma in Japan.

The purpose of this study was to investigate the prevalence of human papillomaviruses (HPVs) 16 and 18 infection, and p53 mutation in oral squamous cell carcinomas (SCCs) in Japanese patients. Our results showed a higher incidence of HPV16 and 18 infections than previous studies because we combined the findings of a consensus polymerase chain reaction (PCR), restriction fragment length polymorphism by using the restriction enzyme digestion of the PCR products and Southern blot hybridization. Each HPV16 and 18 E6/E7 DNA was detected in 9 (20%) and 25 (54%) of 46 samples. The p53 mutation in the exons from 5 to 8 were detected in 20 out of 46 samples (43%) by a PCR-single strand conformation polymorphism analysis. There was a significant relationship between HPV16 and the p53 mutation (P =0.02) suggesting that HPV16 infection has a mutagenic effect in oral SCC. However, neither HPV infection nor p53 mutation influenced survival.

Adult↗
PubMed2000

Incidence of cleft lip or palate in 303738 Japanese babies born between 1994 and 1995.

To investigate the incidence of cleft lip or palate or both (CLP) in Japan, 303738 babies born in 1532 institutions between 1994 and 1995 were examined and 437 (0.14%) were found to have abnormalities. Of these babies, 32.1% had cleft lip, 43.3% had cleft lip and palate, and 24.8% had cleft palate (Table 2). These results show that the incidence of cleft lip and palate has declined compared with the period from 1981 to 1982.

Cleft Lip↗
PubMed2000

Tumor recurrence criteria for postoperative contrast-enhanced computed tomography after surgical treatment of oral cancer and flap repair.

OBJECTIVE: To characterize the computed tomography (CT) findings that distinguish cancer recurrence from postoperative changes that mimic such recurrence. STUDY DESIGN: We evaluated a total of 72 CT scans from 32 patients who had undergone surgery with either pectoralis major myocutaneous flap or forearm flap. The observers evaluated the presence and pattern of enhancement, the presence of low density areas, and changes in the adipose tissue of the flap. RESULTS: A persistent zone of high attenuation over 6 months suggested the high possibility of recurrence. However, an enhancement within 6 months occurred both with the recurrent tumor and with postoperative tissue. In the patients with recurrence (n = 12), the enhanced areas were focal (n = 8) or diffuse (n = 4). Focal-type recurrence often occurred at the posterior margin. The presence of low-density areas and changes in the adipose tissue in the flap are also helpful for detecting recurrence. CONCLUSIONS: The combination of several features seen on CT images can be useful in differentiating tumor recurrence from postoperative tissue changes.

Adipose Tissue↗
PubMed2000

Sulfated glycosaminoglycan synthesis and its regulation by transforming growth factor-beta in rat clonal dental pulp cells.

Dental pulps contain sulfated glycosaminoglycans (GAGs), such as chondroitin 4-sulfate (CSA/4CS), dermatan sulfate (CSB/DS), and chondroitin 6-sulfate (CSC/6CS). Sulfated GAGs play important roles in mineralization and collagen fibrillogenesis during primary, secondary, and reparative dentin formations. Transforming growth factor-beta (TGF-beta) is a potent regulator for several extracellular matrix (ECM) components and modulates the proliferation and differentiation. Using rat clonal dental pulp cells (RPC-C2A), we investigated the constituents of GAGs synthesized by the cells and the effect of TGF-beta on their synthesis by measuring the radioactivity of [35S]sulfate incorporated into GAG fractions. Cellulose acetate electrophoresis analysis revealed that RPC-C2A cells synthesized CSA and CSB but not CSC and that 10 ng/ml of TGF-beta increased the production of CSA and CSB in the cell/ECM fraction. Measurement of [35S]sulfate incorporation showed a significant increase in the amount of GAGs by TGF-beta, 1.3-fold CSA, and 1.2-fold CSB in the cell/ECM fraction. In the medium fraction the most secreted GAG was CSA, whereas CSB was stored in the cell/ECM fraction. Secreted CSA in the medium was markedly increased by 10 ng/ml of TGF-beta (1.7-fold). These findings indicate that CSA and CSB are major sulfated GAGs synthesized by RPC-C2A cells and that TGF-beta acts as a stimulator of sulfated GAG synthesis in dental pulp cells.

Animals↗
PubMed1999

Large-Scale Mapping Observations of the C i (3P1-3P0) and CO (J = 3-2) Lines toward the Orion A Molecular Cloud.

Large-scale mapping observations of the 3P1-3P0 fine-structure transition of atomic carbon (C i, 492 GHz) and the J=3-2 transition of CO (346 GHz) toward the Orion A molecular cloud have been carried out with the Mount Fuji submillimeter-wave telescope. The observations cover 9 deg2 and include the Orion Nebula M42 and the L1641 dark cloud complex. The C i emission extends over almost the entire region of the Orion A cloud and is surprisingly similar to that of 13CO (J=1-0). The CO (J=3-2) emission shows a more featureless and extended distribution than C i. The C i/CO (J=3-2) integrated intensity ratio shows a spatial gradient running from the north (0.10) to the south (1.2) of the Orion A cloud, which we interpret as a consequence of the temperature gradient. On the other hand, the C i/13CO (J=1-0) intensity ratio shows no systematic gradient. We have found a good correlation between the C i and 13CO (J=1-0) intensities over the Orion A cloud. This result is discussed on the basis of photodissociation region models.

Journal Article↗
PubMed1999

A novel dnaK operon from Porphyromonas gingivalis.

The nucleotide sequence of the dnaK operon cloned from Porphyromonas gingivalis revealed that the operon does not contain homologues of either dnaJ or grpE. However, there were two genes which encode small heat shock proteins immediately downstream from the dnaK and they were transcribed together with dnaK as one unit. The ATPase activity of the P. gingivalis DnaK was synergistically stimulated up to 40-fold in the simultaneous presence of Escherichia coli DnaJ and GrpE. These results suggest that the DnaK homologue of P. gingivalis, with its unique genetic structure and evolutionary features, works as a member of the DnaK chaperone system.

Adenosine Triphosphatases↗
PubMed1999

Prevalence of Epstein-Barr virus in oral squamous cell carcinoma.

Forty-six samples of oral squamous cell carcinoma (OSCC) were evaluated for the prevalence of Epstein-Barr virus (EBV) infection by the polymerase chain reaction (PCR), Southern blot hybridization, and in situ hybridization (ISH). EBV DNA was detected in 7 (15.2 per cent) out of 46 samples by a combination of PCR and Southern blot hybridization methods. All seven positive samples showed well-differentiated carcinoma, thus suggesting a possible relationship between EBV infection and the degree of differentiation of carcinoma tissue. Latent infection membrane protein 1 (LMP1) was detected immunohistochemically in six of the EBV-positive OSCCs. However, no signal of the EBV-encoded small RNA (EBER)-1 was demonstrated by the ISH method. No significant relationship was observed between EBV infection and lymph node metastasis. A follow-up study (range from 4.4 to 79 months; mean 34.9 months) showed no recurrence or death to occur in the EBV-positive patients, which thus suggested a good prognosis for EBV-positive OSCC patients.

Adult↗
PubMed1999

Expression of cyclooxygenase-2 in human hepatocellular carcinoma: relevance to tumor dedifferentiation.

Cyclooxygenase (COX) is a key enzyme in the synthesis of prostanoids. Two isoforms of this enzyme have been identified: COX-1 and COX-2. Recent studies have suggested that COX-2, but not COX-1, may play a role in colorectal tumorigenesis. In the present study, we investigated the expression of COX-2 as well as COX-1 in human hepatocellular carcinoma (HCC) tissues using immunohistochemistry and immunoblotting. Forty-four surgically resected HCC tissues with adjacent nontumorous livers (NTs), involving 17 cases of chronic viral hepatitis and 27 cases of cirrhosis, and 7 surgically resected, histologically normal liver tissues were used. The well-differentiated HCC expressed COX-2 more frequently and strongly than less-differentiated HCC or hepatocytes of NTs. Less-differentiated HCCs expressed less COX-2 than hepatocytes of NTs, which showed scattered, strong COX-2 expression. Histologically normal liver was weakly positive for COX-2. The expression of COX-1 was weaker than that of COX-2 in hepatic neoplastic and non-neoplastic parenchymal cells. An enhanced expression of COX-1 was not observed in well-differentiated HCCs. Immunoblotting also confirmed up-regulation of COX-2, but not COX-1, in well-differentiated HCCs. The present study is the first to demonstrate a high expression of COX-2 in well-differentiated HCC and a low expression in advanced HCC, in contrast to its continuous expression during colorectal carcinogenesis. These findings suggested that COX-2 may play a role in the early stages of hepatocarcinogenesis, but not in the advanced stages, and may consequently be related to HCC dedifferentiation.

Adult↗
PubMed1999

Effect of retinoic acid on osteopontin expression in rat clonal dental pulp cells.

We studied the effect of retinoic acid on osteopontin synthesis and the mRNA expression in rat clonal dental pulp cells, RPC-C2A. An immunoprecipitation assay clarified that retinoic acid caused an increase in phosphorylated osteopontin synthesis that was dose-dependent, and marked increases were observed at retinoic acid concentrations of 10(-6) to 10(-5) M (1.7-fold). A Northern blotting analysis revealed a similar pattern of increase in osteopontin mRNA expression of up to 6.2-fold of control levels. Because osteopontin has an important role in the mineralization process, these results suggest that retinoic acid regulates mineralization, which takes place in the pulp cavity, including reparative dentin formation.

Animals↗
PubMed1999

Examination of the roots of paramolar tubercles with computed tomography: report of 3 cases.

Computed tomography was used to examine root anatomy in 3 cases of paramolar tubercles. The images clearly showed the structure of the paramolar tubercles, including their root canal morphology. The root of the paramolar tubercle was united with the distobuccal root in each case. Canals were observed in all tubercles and were connected with the canals in distobuccal roots at various levels. In one case, the imaging information was helpful for endodontic treatment. The clinical importance of knowledge of the root and canal anatomy of these paramolar tubercles is discussed.

Adult↗
PubMed1999

Deletion polymorphism in the gene for angiotensin-converting enzyme is not a risk factor predisposing to abdominal aortic aneurysm.

OBJECTIVE: to establish whether deletion of the angiotensin-converting enzyme (ACE) gene is a risk factor predisposing to abdominal aortic aneurysm (AAA) or not. METHODS: the study included 125 patients with AAA and 153 controls randomly selected from 328 individuals. The control subjects were confirmed not to have an AAA, but matched with the AAA group for age, sex, hypertension, diabetes mellitus, and hyperlipidaemia. The presence of ACE polymorphism was detected by a polymerase chain reaction using DNA extracted from blood. RESULTS: the distribution of ACE genotypes and allele frequencies in the control and AAA groups was not significantly different. CONCLUSION: the deletion polymorphism in the ACE gene is not a risk factor for AAA.

Aged↗
PubMed1999

Detection of hepatitis-C virus and hepatitis-C virus replication in hepatocellular carcinoma by in situ hybridization.

BACKGROUND: Although hepatitis C virus (HCV) is a major causative agent of hepatocellular carcinoma (HCC), the role of this virus in carcinogenesis is not fully understood. METHODS: We studied HCV infection and replication by detecting plus- and minus-strand HCV RNA by in situ hybridization (ISH) in surgically resected HCCs and adjacent non-cancerous tissue obtained from 15 anti-HCV antibody-positive patients with HCC. RESULTS: Plus-strand HCV RNA was found in 9 of 15 HCCs. Both plus- and minus-strand HCV RNA were detected in four of these nine patients. In non-cancerous tissues obtained adjacent to the HCC, plus-strand HCV RNA was found in 10 of 15 patients, whereas both plus- and minus-strand HCV RNA were detected in 7 of these 10 patients. The degree of staining by ISH did not correlate with the differentiation of the HCC, histologic classification of the non-cancerous tissue, serum HCV RNA levels, or serum transaminase levels. CONCLUSIONS: HCV can be found in and replicates in both hepatoma cells and in non-cancerous hepatocytes in anti-HCV antibody-positive patients with HCC. The direct effects of HCV viral gene products on normal hepatocytes in the development of HCC require additional study.

Aged↗
PubMed1999

Upregulation of renin-angiotensin system during differentiation of monocytes to macrophages.

BACKGROUND: We have demonstrated that accumulated macrophages in human coronary arteries strongly express angiotensin converting enzyme in accordance with the development of atheromatous plaques. However, there are few reports on the regulation of the renin-angiotensin system in macrophages and in monocytes as their source. OBJECTIVE: To examine whether the renin-angiotensin system is upregulated during the differentiation of monocytes to macrophages, and whether it is further regulated by angiotensin II and cytokines. MATERIALS AND METHODS: We used a human leukemia cell line, THP-1, for monocytes. Differentiated THP-1, induced by adding phorbol 12-myristate 13-acetate for 24 h, were used as macrophages. Expression of messenger RNA of the renin-angiotensin system components was measured by quantitative reverse-transcriptase polymerase chain reaction. Angiotensin converting enzyme activity and subtype-specific angiotensin-binding sites of cultured cells, and angiotensin II production in the culture medium were measured. RESULTS: Macrophages expressed all components of the renin-angiotensin system except chymase. Cellular angiotensin converting enzyme activity and angiotensin II in the medium were increased 3.2- and 4.5-fold during differentiation, respectively. Expression of angiotensin II type 1 (AT1) and type 2 (AT2) receptors was increased 6.2-and 6.4-fold during differentiation, and was sustained for 7 days. Incubation with angiotensin II for 24 h caused downregulation of both AT1 and AT2 receptor messenger RNA, but the expression levels were still more than threefold higher compared with monocytes. The density of binding sites of AT1 and AT2 receptors in macrophages was 0.26 +/- 0.02 and 0.15 +/- 0.01 fmol/10(6) cells, respectively. CONCLUSION: The renin-angiotensin system is markedly activated during monocyte/macrophage differentiation, and may participate in the development of atherosclerosis.

Angiotensin II↗
PubMed1999

Relative localization of angiotensin-converting enzyme, chymase and angiotensin II in human coronary atherosclerotic lesions.

BACKGROUND: Studies using cell cultures and animal models have indicated an important role for angiotensin II in atherosclerosis. In humans, at least two major enzymes are involved in the conversion of angiotensin I to angiotensin II: so-called angiotensin-converting enzyme (ACE) and chymase. Enhanced activation of chymase in atherosclerotic tissue homogenates has been reported in animal models, but its contribution to the generation of angiotensin II has not been studied. OBJECTIVE: To clarify the localization of chymase and its pathophysiologic role in the formation of angiotensin II, using human coronary arteries. DESIGN AND METHODS: Twenty-four coronary artery segments obtained from 14 autopsied patients were characterized histologically into the following categories: normal coronary arteries with diffuse intimal thickening, hypercellular lesions, atheromatous plaques and fibrosclerotic plaques. We compared the cellular localization of chymase, ACE and angiotensin II expression using immunocytochemical techniques. RESULTS: Chymase was expressed only in the cytosole of mast cells in all segments. On the basis of the histologic study, the number of chymase-positive cells in the intima of atheromatous plaques was significantly higher than that in normal coronary arteries with diffuse intimal thickening. The expression of angiotensin II in the intima was enhanced in hypercellular lesions and atheromatous plaques. Localization of angiotensin II in the intima was associated with that of ACE. Immunodouble staining did not show colocalization of angiotensin II and chymase. CONCLUSIONS: These results suggest an important role for the production of angiotensin II by ACE in the progression of atherosclerosis in human coronary arteries. Enhanced expression of chymase appears not to be involved in angiotensin II production in the intima.

Adolescent↗
PubMed1999

Angiotensin II type 1 receptor-mediated peroxide production in human macrophages.

Our previous experiments demonstrated upregulation of the renin-angiotensin system in macrophages, including angiotensin II type 1 (AT1) and type 2 (AT2) receptors, during transformation from monocytes. We investigated the role of angiotensin II in oxidative stress of monocytes/macrophages, which plays a role in the advance of atherosclerosis. THP1, a human monocytic leukemia cell line, was differentiated to macrophages by adding of phorbol 12-myristate 13-acetate for 24 hours. The intracellular production of peroxide was measured by a cytofluorometric assay with 2', 7'-dichlorofluorescein-diacetate with a flow cytometer scan. Peroxide was detected in monocytes and upregulated during the transformation to macrophages by 3.18+/-0.52 times in relative fluorescein of peak value (P<0.01). Angiotensin II (1 micromol/L) induced oxidative stress in macrophages, with the peak at 15 minutes by 451+/-223%, and returned to the control level within 1 hour. EC50 was 5.4x10(-9) mol/L. AT1 antagonist (CV11974, 1 micromol/L) significantly decreased angiotensin II-induced oxidative stress in macrophages, but AT2 antagonist (PD123319, 1 micromol/L) did not. Of interest, AT1 antagonist also decreased basal levels of peroxide production in macrophages in a dose-dependent manner. These results suggest that upregulation of the expression of AT1 receptor in macrophages contributes in part to upregulation of peroxide production. AT1 receptor antagonists may be useful to suppress oxidative stress of macrophages in atherosclerotic lesions.

Angiotensin II↗