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Biomedical subjects

M Shinohara

Publications and source records attributed to M Shinohara.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Evaluation of 18F-FDG positron emission tomography (PET) in the detection of unknown primary tumors].

18F-fluorodeoxyglucose positron emission tomography was able to identify previously unknown primary tumors in 2 of 4 patients after an unsuccessful conventional diagnostic workup such as chest radiography, ultrasound, computed tomography, MRI and various endoscopies. The 2 patients in which the primary tumors were detected proved to have a carcinoma of the lung, one of the patients received radiotherapy and chemotherapy after the detection of the primary tumor by FDG PET. The primary tumor of the lung demonstrated no focal FDG uptake after the successive treatment. On the other hand, in one patient with prostatic carcinoma and another in which the primary tumor has yet to be detected, FDG PET was unable to identify the primary tumor. This suggests a limitation of PET studies in detecting cancers. Because of increased glycolysis in cancer cells, FDG PET can be used to detect cancers with its high sensitivity, surveying the entire body non-invasively in one session. PET has the advantage of detecting primary tumors of an unknown origin when compared to conventional diagnostic studies.

Aged↗
PubMed1999

Biochemical and physiological properties of pedicellarial lectins from the toxopneustid sea urchins.

Pedicellarial lectins (SUL-I, SUL-II, and TGL-I) were purified from the toxopneustid sea urchins, Toxopneustes pileolus and Tripneustes gratilla using gel filtration chromatography, affinity chromatography, and reverse-phase HPLC. SUL-I (Nakagawa et al., 1996) and SUL-II from the large globiferous pedicellariae of T. pileolus are D-galactose-binding lectins with molecular masses of 32 kDa and 23 kDa, respectively; while TGL-I from the globiferous pedicellariae of T. gratilla is a Ca(2+)-independent heparin-binding lectin with a molecular mass of 23 kDa. SUL-I induced mitogenic stimulation on murine splenocytes but TGL-I did not. At higher dose ranges SUL-I exhibited inhibitory effects on the cells. The dual response to SUL-I was effectively inhibited by D-galactose. SUL-I enhanced norepinephrine-induced contraction of isolated rat mesenteric artery with endothelium. When endothelium was removed from the artery, acetylcholine did not relax the norepinephrine-induced contraction. In the same artery the enhancing effect of the contraction by SUL-I was abolished, suggesting that SUL-I acts on the endothelium of mesenteric artery, and may release prostanoids. The present results suggest an extracellular function for SUL-I that may have wide-ranging effects in physiological processes. The primary role of pedicellarial lectins from T. pileolus and T. gratilla might be defense against a foreign body.

Agglutination↗
PubMed1999

Effect of insulin on naturally occurring gingivitis rats with diabetes.

It is well known that diabetes mellitus aggravates both the severity and progression of periodontal disease. We sought to further explore biologic mechanisms of this relationship using naturally occurring gingivitis rats (ODUS/Odu) rendered diabetic by 65 mg/kg intravenous injection of streptozotocin (STZ). Insulin was administered daily to one group of the rats beginning 4 weeks after STZ injection (STZ-insulin group). Others received no insulin (STZ group). A third group that received no STZ was kept as controls. Eight weeks after STZ injection, sterilized liquid paraffin was injected peritoneally into all three groups, and peritoneal macrophages were collected 4 days later. Macrophage chemotaxis was measured by the membrane filter method using a 48-well microchemotaxis chamber with zymosan activated serum used as a chemotactic stimulant. Blood glucose levels, body weight, plaque indices, pocket depths, serum triglyceride and hemoglobin A1C levels were also determined. We found that blood glucose levels, body weight and triglycerides recovered to normal values in the STZ-insulin group. Further, control of blood glucose resulted in diminished plaque indices, and pocket depths returned to values seen in the controls. Chemotaxis and phagocytosis of peritoneal macrophages improved slightly in the STZ-insulin group, but did not return to levels seen in the pretreatment state. Although insulin resulted in some improvement in leukocyte function damaged by induced diabetes mellitus, recovery was incomplete.

Animals↗
PubMed1999

Coagulation and fibrinolytic activity in rats with naturally occurring gingivitis.

It is well known that there are several coagulation factors and fibrinolysis factors, and these inhibitors are also present in blood and tissues. Normally, these factors balance each other. We measured antithrombin III (AT III), an important inhibitor of coagulation and alpha 2-plasmin inhibitor (alpha 2-PI), a factor inhibiting fibrinolysis in blood and gingival tissue of naturally occurring gingivitis rats (ODUS/Odu) and control rats (Res). Blood plasma and supernatants of gingival homogenate from ODUS/Odu and Res were used as samples. And concentrations of alpha 2-PI and AT III were measured by colorimetric assay using commercially available reagents. We found no difference in blood concentrations of alpha 2-PI or AT III between ODUS/Odu and Res groups. However, AT III in the gingiva showed a significantly higher value in the ODUS/Odu group versus that in the controls (p < 0.001). There was a high positive correlation between AT III in gingival tissue and pocket probing depth. Moreover, the fibrinolytic activity in saliva and the gingiva from ODUS/Odu increased with each passing month. Results suggest that both the decrease in blood coagulability and systemic enhancement of fibrinolytic activity due to increased AT III in gingival tissue are associated with the bleeding tendency and inflammatory response in the gingiva of ODUS/Odu.

Animals↗
PubMed1998

Lactone-ring-cleaving enzyme: genetic analysis, novel RNA editing, and evolutionary implications.

A lactonohydrolase from Fusarium oxysporum AKU 3702 is an enzyme catalyzing the hydrolysis of aldonate lactones to the corresponding aldonic acids. The amino acid sequences of the NH2 terminus and internal peptide fragments of the enzyme were determined to prepare synthetic oligonucleotides as primers for the PCR. An approximate 1, 000-base genomic DNA fragment thus amplified was used as the probe to clone both genomic DNA and cDNA for the enzyme. The lactonohydrolase genomic gene consists of six exons separated by five short introns. A novel type of RNA editing, in which lactonohydrolase mRNA included the insertion of guanosine and cytidine residues, was observed. The predicted amino acid sequence of the cloned lactonohydrolase cDNA showed significant similarity to those of the gluconolactonase from Zymomonas mobilis, and paraoxonases from human and rabbit, forming a unique superfamily consisting of C-O cleaving enzymes and P-O cleaving enzymes. Lactonohydrolase was expressed under the control of the lac promoter in Escherichia coli.

Amino Acid Sequence↗
PubMed1998

Involvement of proteasomes in migration and matrix metalloproteinase-9 production of oral squamous cell carcinoma.

We investigated whether proteasomes were involved in the invasiveness of oral squamous cell carcinoma (SCC) cells. The migration of SCC cells through a gelatin-coated membrane was enhanced with tumor necrosis factor alpha (TNF alpha), which was strongly inhibited by a peptide aldehyde, N-acetyl-Leu-Leu-norleucinal (ALLN), but not by its structurally related compound, N-acetyl-Leu-Leu-methioninal (ALLM). Since ALLN is a more potent inhibitor against proteasomal proteolysis than ALLM, cell migration inhibited by ALLN may thus likely depend on proteasomes. The TNF alpha-induced migration through gelatin appeared to be associated with the gelatinolytic activity from the cells, since TNF alpha strongly enhanced the production of matrix metalloproteinase (MMP)-9/gelatinase B in the SCC cells, as detected by gelatin zymography. The production of MMP-9 was also inhibited by pretreatment with ALLN, but not ALLM, in a dose-dependent manner. Moreover, ALLN could block the activation and nuclear translocation of a transcription-activating factor, NF-kappaB, which is known to regulate MMP-9 expression in TNF alpha-stimulated SCC cells. The TNF alpha-induced degradation of IkappaB alpha was also suppressed by ALLN treatment, thus implying that the molecule linking proteasome to MMP-9 production should be IkappaB alpha. We finally reconfirmed the involvement of proteasomes in the invasive behavior of oral SCC using lactacystin, a specific proteasome inhibitor, which could prevent TNF alpha from enhancing MMP-9 production, NF-kappaB activation, induction of MMP-9 mRNA and cell migration.

Carcinoma, Squamous Cell↗
PubMed1998

Overexpression of glyoxalase-I in bovine endothelial cells inhibits intracellular advanced glycation endproduct formation and prevents hyperglycemia-induced increases in macromolecular endocytosis.

Methylglyoxal (MG), a dicarbonyl compound produced by the fragmentation of triose phosphates, forms advanced glycation endproducts (AGEs) in vitro. Glyoxalase-I catalyzes the conversion of MG to S-D-lactoylglutathione, which in turn is converted to D-lactate by glyoxalase-II. To evaluate directly the effect of glyoxalase-I activity on intracellular AGE formation, GM7373 endothelial cells that stably express human glyoxalase-I were generated. Glyoxalase-I activity in these cells was increased 28-fold compared to neo-transfected control cells (21.80+/-0.1 vs. 0. 76+/-0.02 micromol/min/mg protein, n = 3, P < 0.001). In neo-transfected cells, 30 mM glucose incubation increased MG and D-lactate concentration approximately twofold above 5 MM (35.5+/-5.8 vs. 19.6+/-1.6, P < 0.02, n = 3, and 21.0+/-1.3 vs. 10.0+/-1.2 pmol/ 10(6) cells, n = 3, P < 0.001, respectively). In contrast, in glyoxalase-I-transfected cells, 30 mM glucose incubation did not increase MG concentration at all, while increasing the enzymatic product D-lactate by > 10-fold (18.9+/-3.2 vs. 18.4+/- 5.8, n = 3, P = NS, and 107.1+/-9.0 vs. 9.4+/-0 pmol/10(6) cells, n = 3, P < 0.001, respectively). After exposure to 30 mM glucose, intracellular AGE formation in neo cells was increased 13.6-fold (2.58+/-0.15 vs. 0.19+/-0.03 total absorbance units, n = 3, P < 0.001). Concomitant with increased intracellular AGEs, macromolecular endocytosis by these cells was increased 2.2-fold. Overexpression of glyoxalase-I completely prevented both hyperglycemia-induced AGE formation and increased macromolecular endocytosis.

Acetone↗
PubMed1998

Immunohistochemical study of desmosomes in oral squamous cell carcinoma: correlation with cytokeratin and E-cadherin staining, and with tumour behaviour.

Reduction or loss of the intercellular junctions known as desmosomes may contribute to the invasive and metastatic behaviour of various carcinomas. Previous studies have shown that metastasis of oral squamous cell carcinomas of the head and neck correlates with a reduction in immunohistochemical staining for desmoplakin and desmoglein at the invasion front. The primary aim of the present study was to extend these observations to include a third component of desmosomes, the glycoprotein desmocollin. An additional aim was to determine whether the differentiation status of tumours is reflected in their staining for cytokeratins 1, 13, and 19, and, if so, whether these parameters correlate with desmosomal staining and/or metastasis. The study included 54 primary tumours of which 28 showed lymph node metastases. The results of this investigation show that tumours can be divided into three groups according to whether they have lost staining for no, one or more than one desmosomal component. A statistically significant correlation was found between the number of desmosomal components lost and metastasis. Tumours could also be divided into five groups according to their staining for different combinations of cytokeratins. Furthermore, differentiation status as indicated both histologically and by cytokeratin staining correlated with reduced desmosomal staining and metastasis. Tumours were also examined for intensity of staining for the adhesion molecule E-cadherin. Reduction in E-cadherin staining was correlated with mode of invasion and with reduction in desmosomal staining, but not with poor differentiation as indicated by cytokeratin staining. The results of this extensive study reinforce the view that adhesive junctions and adhesion molecules contribute to the suppression of tumour invasion and metastasis.

Adult↗
PubMed1998

Accumulation of human T lymphotropic virus type I-infected T cells in the salivary glands of patients with human T lymphotropic virus type I-associated Sjögren's syndrome.

OBJECTIVE: To clarify the involvement of human T lymphotropic virus type I (HTLV-I) in the pathogenesis of Sjogren's syndrome (SS). METHODS: In HTLV-I-seropositive patients with SS, HTLV-I proviral DNA in the labial salivary glands (SG) was detected by polymerase chain reaction (PCR) amplification of the extracted cellular DNA, and the localization in the SG was examined by in situ PCR hybridization. RESULTS: The cellular DNA extracted from the SG contained full HTLV-I proviral DNA, which was present in the nucleus of the infiltrating T cells, but not in either the SG epithelial cells or the acinar cells. Furthermore, the viral loads in the SG were approximately 8 times to 9 x 10(3) times higher than those in the peripheral blood mononuclear cells. CONCLUSION: Accumulation of HTLV-I-infected T cells in the SG suggests that HTLV-I likely causes the self-reactive T cells to proliferate, which, as a result, induces SS.

Adult↗
PubMed1998

Efficacy of tourniquet ischemia for strength training with low resistance.

To investigate the efficacy of ischemia in strength training with low mechanical stress, tourniquet ischemia was utilized in low-resistance training. Five untrained subjects conducted one-legged isometric knee extension training with one leg ischemic (I-leg) and the other non-ischemic (NI-leg). Repeated isometric contractions for 2 s with 3 s relaxation in between were continued for 3 min and conducted 3 days/week for 4 weeks as training. Training resistance was 40% of maximal voluntary contraction (MVC) of respective leg and tourniquet ischemia was applied during I-leg training. MVC in I-leg after 2 weeks (9% gain) and 4 weeks (26% gain) were significantly higher than pre-training value (p < 0.05). A significant increase in maximal rate of torque development in I-leg was observed after 4 weeks (p < 0.05). On the contrary, there was no significant changes in either of the parameters in NI-leg. As a consequence, the differences between legs for both parameters were significant after 2 and 4 weeks (p < 0.05 or p < 0.01). The substantial gain in strength and maximal rate of torque development in I-leg demonstrated the efficacy of tourniquet ischemia during low-resistance training of short duration, and suggested the importance of neuromuscular and/or metabolic activity, other than high mechanical stress, to the adapting responses to strength training.

Adult↗
PubMed1998

Mechanomyogram from the different heads of the quadriceps muscle during incremental knee extension.

To investigate the time- and frequency-domain responses of mechanomyograms (MMGs) during the progressive fatigue induced by intermittent incremental contractions, a surface MMG was obtained from the three muscle heads of the quadriceps muscle in seven subjects while they performed isometric knee extensions lasting 7.6 min. Isometric intermittent incremental contractions started at 1% of the maximal voluntary contraction (MVC) for 3 s, with a 3-s relaxation period in between each contraction, and the contraction level was increased by 1% of MVC for every contraction (by 10% of MVC per min) up to exhaustion. Separate contractions with sufficient rest periods were also conducted to serve for the MMG characteristics without fatigue. The integrated MMG (iMMG) was linearly related to force in all of the muscles when fatigue was not involved. With regard to the incremental contractions, the relationship exhibited an ascending-descending shape, but the behavior was not the same for the individual muscle heads, especially for the rectus femoris muscle. A steep increase in the median frequency of MMG from around 60% of MVC corresponded to a decrease in iMMG. These results suggest that analysis of MMG in the time- and frequency-domain during an incremental protocol is a useful way of characterizing the motor unit recruitment strategy and fatigue properties of individual muscles.

Adult↗
PubMed1998

Secretory carcinoma of the breast in an elderly woman: report of a case.

We herein report a case of secretory carcinoma of the breast in a 73-year-old woman. Secretory carcinoma is an extremely rare tumor and demonstrates distinctive pathologic characteristics. This tumor frequently occurs in either children or adolescents, and thus has been called juvenile carcinoma. We encountered this rare tumor in an elderly woman. Aspiration biopsy cytology was performed twice, but the cytological diagnosis was not carcinoma. Such pathologic characteristics as mild atypia, the absence of hyperchromasia, and a minimal degree of pleomorphism in the tumor cells can thus lead to a cytological misdiagnosis. An excisional biopsy was performed and secretory carcinoma was finally diagnosed. Consequently, a modified radical mastectomy (Kodama's method) was performed 7 days later. We describe this very rare tumor's clinicopathologic characteristics.

Age Factors↗
PubMed1998

Mesh plug repair for a small incisional hernia in a cirrhotic patient with ascites: report of a case.

We report herein the case of a patient with severe liver ascites due to cirrhosis in whom a small incisional hernia on a midline incision was successfully treated by a mesh plug repair, a method most commonly employed for groin hernia repair. The hernia sac was dissected and inverted into the abdominal cavity by the mesh plug under epidural anesthesia. The patient's recovery was quick and relatively painless, and there has been no recurrence after 1 year of followup. This case report demonstrates that the method of mesh plug repair may be appropriate for small incisional hernias as well as groin hernias, performed under epidural anesthesia.

Ascites↗
PubMed1998

Involvement of CD14 on human gingival fibroblasts in Porphyromonas gingivalis lipopolysaccharide-mediated interleukin-6 secretion.

The lipopolysaccharides (LPS) of Porphyromonas gingivalis are implicated in the initiation and development of periodontal diseases. However, the mechanisms underlying P. gingivalis LPS-mediated periodontal destruction are still unknown. Here, it was found that P. gingivalis LPS activates human gingival fibroblasts (HGF) to release interleukin 6 (IL-6) via CD14. Flow-cytometric analysis showed that HGFs bind to fluorescein-isothiocyanate (FITC)-labelled LPS, and express CD14 on their surfaces. The binding of FITC LPS was competitively suppressed by unlabelled synthetic lipid A as well as by LPS. LPS-induced IL-6 production was inhibited by anti-CD14 monoclonal antibody in a dose-dependent manner. The binding of FITC LPS to HGF was abrogated by anti-CD14 monoclonal antibody. Engagement of LPS initiated the protein tyrosine phosphorylation of several intracellular proteins including extracellular signal-regulated kinase (ERK) 1 and 2, and these events were suppressed by the anti-CD14 monoclonal. These results suggest that CD14 is a cell surface binding site for LPS and is involved in the LPS-mediated activation of HGF.

Antibodies, Monoclonal↗
PubMed1998

Imaging findings of some buccomasseteric masses.

OBJECTIVE: The purpose of this study was to review and illustrate the appearances on diagnostic images of pathologic conditions of the buccomasseteric region. STUDY DESIGN: Computed tomographic, sonographic, and magnetic resonance images of the buccomasseteric masses were reviewed retrospectively. RESULTS: In our series of 66 cases, there were 60 benign lesions; of these, 21 were benign masses, 11 were inflammations, and 28 were myopathies. The most common pathologic condition of the buccomasseteric region was masseteric hypertrophy (n = 22). The most common lesion manifesting as a benign mass in this series was hemangioma (n = 10), which was followed by lipoma (n = 6). Six of the 66 patients had malignant tumors. CONCLUSIONS: Computed tomography and magnetic resonance imaging were useful in demonstrating the location and extent of the buccomasseteric masses. Sonography provided clear images of internal architectures of the mass in this region.

Adolescent↗
PubMed1998

Synovial chondromatosis of the temporomandibular joint: the effect of interleukin-1 on loose-body-derived cells.

OBJECTIVE: The purpose of this study was to investigate the effect of interleukin-1 on cells from loose bodies of synovial chondromatosis of the temporomandibular joint. STUDY DESIGN: The cells were isolated from uncalcified loose bodies in a case of synovial chondromatosis of the temporomandibular joint and cultured in alpha-MEM medium containing 10% fetal bovine serum. The cells were treated with or without interleukin-1alpha and then stained with toluidine blue. Their conditioned media were analyzed with gelatin zymography to detect matrix-degrading proteinase(s). RESULTS: The cells from loose bodies produced toluidine-blue-stained matrix. When the cells were treated with 100 ng/ml of interleukin-1alpha for 3 days, toluidine-blue-stained matrix was strikingly reduced. Gelatin zymography revealed that interleukin-1alpha-treated cells released 62-kDa gelatinase. CONCLUSIONS: Interleukin-1alpha may lead loose-body-derived cells to degrade the cartilaginous matrix of loose bodies in synovial chondromatosis of the temporomandibular joint.

Animals↗