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Biomedical subjects

N Nakamura

Publications and source records attributed to N Nakamura.

At least 163 records · Page 9Linked to original sources
PubMed2000

Cytologic differential diagnosis among reactive mesothelial cells, malignant mesothelioma, and adenocarcinoma: utility of combined E-cadherin and calretinin immunostaining.

BACKGROUND: The differential diagnosis between reactive mesothelial cells (RMs), malignant mesotheliomas (MMs), and adenocarcinomas (ACs) is often difficult in cytologic specimens, and the utility of various immunohistochemical markers have been explored. Because recent immunohistologic studies have suggested that E-cadherin (E-cad) and calretinin (Cal) may be useful markers for epithelial and mesothelial differentiations, respectively, the authors investigated their utility in cytologic diagnosis. METHODS: In this retrospective study, immunostaining was performed on smears retrieved from Papanicolaou-stained slides of effusions using the labeled streptavidin-biotin method. Sixteen cases of RM, 9 cases of MM, and 52 cases of AC from various sites, including 13 pulmonary primaries, were examined with primary antibodies against E-cad and Cal. RESULTS: The positive rates for E-cad and Cal, respectively, were as follows: RM, 0/16 (0%) and 16/16 (100%); MM, 9/9 (100%) and 8/8 (100%); and AC, 45/52 (86.5%) and 0/51 (0%). The E-cad expression by neoplastic cells was strongest in the intercellular junctions, and poorly differentiated neoplastic cells in the single cell form showed the weakest expression. CONCLUSIONS: In contrast to the results of previous immunohistochemical studies, the current study indicates that MMs constantly express E-cad, whereas RMs lack its expression in cytologic specimens, which would be useful in the differential diagnosis between the two. On the other hand, E-cad expression is not reliable for distinguishing AC from MM. The Cal expression can be a very useful marker for the distinction between AC and the mesothelial lineage. The combined immunostaining for E-cad and Cal has utility in differential diagnosis among RM, MM, and AC.

Adenocarcinoma↗
PubMed2000

Regulation and reversibility of vacuolar H(+)-ATPase.

Arabidopsis thaliana vacuolar H(+)-translocating pyrophosphatase (V-PPase) was expressed functionally in yeast vacuoles with endogenous vacuolar H(+)-ATPase (V-ATPase), and the regulation and reversibility of V-ATPase were studied using these vacuoles. Analysis of electrochemical proton gradient (DeltamuH) formation with ATP and pyrophosphate indicated that the proton transport by V-ATPase or V-PPase is not regulated strictly by the proton chemical gradient (DeltapH). On the other hand, vacuolar membranes may have a regulatory mechanism for maintaining a constant membrane potential (DeltaPsi). Chimeric vacuolar membranes showed ATP synthesis coupled with DeltamuH established by V-PPase. The ATP synthesis was sensitive to bafilomycin A(1) and exhibited two apparent K(m) values for ADP. These results indicate that V-ATPase is a reversible enzyme. The ATP synthesis was not observed in the presence of nigericin, which dissipates DeltapH but not DeltaPsi, suggesting that DeltapH is essential for ATP synthesis.

Adenosine Triphosphate↗
PubMed2000

Reduced expression of p27/Kip1 is associated with the development of pulmonary adenocarcinoma.

p27/Kip1 (p27), a negative regulator of cell proliferation, is a powerful prognostic marker in non-small cell lung carcinoma. To clarify the significance of p27 aberrations in the tumourigenesis of lung adenocarcinoma, p27 expression was investigated by immunohistochemistry in lung adenocarcinoma and its precursor lesion, atypical adenomatous hyperplasia (AAH), and correlated with the expression of Ki-67, cyclin D1, and cyclin E. The p27 labelling index decreased in parallel with tumour progression (24.0% to 4.5%) and was found to be lower in neoplastic lesions than in normal bronchiolar epithelial cells (48.8%). There was a negative correlation between p27 and Ki-67 expression (rho=-0.384, p<0.001). Cyclin E-positive lesions (with labelling index >/=5%) were found only in overt adenocarcinomas. The Ki-67 labelling index of cyclin E-positive, high (>/=10%) p27 expressers was lower than that of cyclin E-positive, low (<10%) p27 expressers (16.8% vs. 42.6%; p=0. 046) and was similar to that of cyclin E-negative adenocarcinomas (15.0%). These results indicate that reduced p27 expression is associated with and may play a role in progression during the development of pulmonary adenocarcinoma.

Adenocarcinoma↗
PubMed2000

Functional reconstitution of an active recombinant human chymase from Pichia pastoris cell lysate.

We have previously reported efficient production of mature human chymase (h-chymase) using an original system of expression in Pichia pastoris (Nakakubo et al., 2000), whereby recombinant h-chymase (rh-chymase) was secreted as a mature form with the correct N-terminal amino acid sequence and was easily purified. In the course of investigation of secretory rh-chymase, we also found large amounts of chymase to be present in insoluble form in the transformant cell. Although the cellular rh-chymase had no proteolytic activity, its chymotryptic activity was restored in a reconstitution process utilizing guanidine and glutathione. As with secretory rh-chymase, efficient purification was possible by heparin affinity chromatography. The purified cellular rh-chymase showed the same mobility as secretory rh-chymase in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) before and after deglycosylation. N-terminal amino acid sequence analysis revealed that the signal peptide had been correctly removed. K(m) value (5.93 mM), as well as pH profile and inhibition profile toward protease inhibitors of reconstituted cellular rh-chymase, indicated that the rh-chymase enzymatically closely resembles native h-chymase. Furthermore, it showed a greatly restricted proteolytic activity towards Ang I, and formed Ang II without the further cleavage which is a feature of h-chymase. It was thus found that the insoluble rh-chymase stored in the cells could be solubilized and reconstituted to give the same structure as h-chymase, not only in terms of enzyme active site but also of substrate recognition site.

Amidohydrolases↗
PubMed2000

Inhibitory effects of sudanese medicinal plant extracts on hepatitis C virus (HCV) protease.

One hundred fifty-two methanol and water extracts of different parts of 71 plants commonly used in Sudanese traditional medicine were screened for their inhibitory effects on hepatitis C virus (HCV) protease (PR) using in vitro assay methods. Thirty-four extracts showed significant inhibitory activity (>/=60% inhibition at 100 microg/mL). Of these, eight extracts, methanol extracts of Acacia nilotica, Boswellia carterii, Embelia schimperi, Quercus infectoria, Trachyspermum ammi and water extracts of Piper cubeba, Q. infectoria and Syzygium aromaticum, were the most active (>/=90% inhibition at 100 microg/mL). From the E. schimperi extract, two benzoquinones, embelin (I) and 5-O-methylembelin (II), were isolated and found as potent HCV-PR inhibitors with IC(50) values of 21 and 46 microM, respectively. Inhibitory activities of derivatives of I against HCV-PR as well as their effects on other serine proteases were also investigated.

Chromatography, High Pressure Liquid↗
PubMed2000

Decorin antisense gene therapy improves functional healing of early rabbit ligament scar with enhanced collagen fibrillogenesis in vivo.

Injured ligaments heal with scar tissue, which has mechanical properties inferior to those of normal ligament, potentially resulting in re-injury, joint instability, and subsequent degenerative arthritis. In ligament scars, normal large-diameter collagen fibrils have been shown to be replaced by a homogenous population of small collagen fibrils. Because collagen is a major tensile load-bearing matrix element and because the proteoglycan decorin is known to inhibit collagen fibrillogenesis, we hypothesized that the restoration of larger collagen fibrils in a rabbit ligament scar, by down-regulating the proteoglycan decorin, would improve the mechanical properties of scar. In contrast to sense and injection-treated controls, in vivo treatment of injured ligament by antisense decorin oligodeoxynucleotides led to an increased development of larger collagen fibrils in early scar and a significant improvement in both scar failure strength (83-85% improvement at 6 weeks; p < 0.01) and scar creep elongation (33-48% less irrecoverable creep; p < 0.03) under loading. This is the first report that in vivo manipulation of collagen fibrillogenesis improves tissue function during repair processes with gene therapy. These findings not only suggest the potential use of this type of approach to improve the healing of various soft tissues (skin, ligament, tendon, and so on) but also support the use of such methods to better understand specific structure-function relationships in scars.

Animals↗
PubMed2000

Apoptosis in rat cardiac myocytes induced by Fas ligand: priming for Fas-mediated apoptosis with doxorubicin.

Fas/Fas ligand (FasL) is well known for its role in delivering apoptotic signals; however, it is unclear whether FasL can mediate apoptosis in cardiomyocytes. We hypothesized that apoptosis via Fas/FasL system may be augmented in damaged cardiomyocytes. To determine whether FasL mediates cardiomyocyte apoptosis, recombinant FasL (rFasL) was added to the culture of neonatal rat ventricular myocytes pretreated with and without doxorubicin. Without doxorubicin, high dose of rFasL caused an increase in TUNEL-positive cardiomyocytes and a mild decrease in MTT activities. When cardiomyocytes were pretreated with doxorubicin (0.5 microM), rFasL dramatically augmented TUNEL-positive cardiomyocytes in a concentration-dependent manner, which was accompanied with nuclear fragmentations. The rFasL also caused a concentration-dependent reduction in MTT activities in cardiomyocytes. The rFasL-induced caspase-8 activity was greatly facilitated by pretreatment of doxorubicin. TUNEL-positive nuclei with rFasL was inhibited by Fas-Fc, neutralizing agent of rFasL, and Z-IETD-FMK, caspase-8 inhibitor. Fas mRNA transcript by RT-PCR was up-regulated in cardiomyocytes with doxorubicin. We conclude that FasL can induce cardiomyocyte apoptosis particularly when cardiomyocyte becomes susceptible for Fas-mediated apoptosis.

Animals↗
PubMed2000

Serum concentrations of soluble Fas antigen and soluble Fas ligand in mother and newborn.

We measured soluble Fas antigen and soluble Fas ligand, which are considered to be an apoptotic substance, in maternal serum, umbilical cord serum and amniotic fluid during cesarean section at full term pregnancy. Seventeen healthy parturients with no fetal distress were studied. Soluble Fas antigen showed no different levels between these measurement sites. Soluble Fas ligand showed a difference, in which umbilical serum level was significantly higher than maternal serum and amniotic fluid levels. The present results suggest high serum levels of soluble Fas ligand in newborn. However, the reason for this evidence is entirely unknown.

Adult↗
PubMed2000

Interstitial pneumonia in Hermansky-Pudlak syndrome: significance of florid foamy swelling/degeneration (giant lamellar body degeneration) of type-2 pneumocytes.

Although usual interstitial pneumonia (UIP)-like IP has been known as the most serious complication of Hermansky-Pudlak syndrome (HPS), its pathologic features and pathogenesis are poorly understood. We investigated biopsied and autopsied lung tissues from five patients who died of UIP-like IP associated with HPS (HPSIP). The salient histopathologic features of HPSIP observed were: (1) alveolar septa displaying florid proliferation of type-2 pneumocytes (2PCs) with characteristic foamy swelling/degeneration; (2) patchy fibrosis with lymphocytic and histiocytic infiltration centered around respiratory bronchioles, occasionally showing constrictive bronchiolitis; and (3) honeycomb change without predilection for the lower lobes or subpleural area. Those peculiar 2PCs were histochemically characterized by the over accumulation of phospholipid, immunohistochemically by a weak positivity for surfactant protein, and ultrastructurally by the presence of numerous giant lamellar bodies that compressed the nucleus with occasional cytoplasmic disruption, together suggesting a form of cellular degeneration with an over accumulation of surfactant (giant lamellar body degeneration). The present study strongly indicates that there is a basic defect in the formation/secretion process of surfactant by the 2PCs in HPS, which may well be the triggering factor for the HPSIP development. Other factors, such as macrophage dysfunction, may be working synergistically for further acceleration of the inflammatory process.

Adult↗
PubMed2000

Multiple duodeno-jejunal diverticula causing massive intestinal bleeding.

A case of massive intestinal blood loss from multiple duodeno-jejunal diverticula is described. A 39-year-old man was referred to our hospital because of recurrent bloody stool and worsening anemia. Upper and lower endoscopy, selective abdominal angiography, and radionuclide scanning were performed to seek the cause of the intestinal bleeding, but none of these studies revealed the source of bleeding. Small-bowel barium follow-through examination showed numerous diverticula in the distal duodenum and proximal jejunum. Excision of the duodenal diverticulum and resection of the involved portion of the jejunum cured the patient. On histopathological examination, an ulcerative lesion with an exposed vessel suggestive of the source of bleeding was seen in the resected duodenal diverticulum. Although duodeno-jejunal diverticula are rare, the importance of a careful search for this malformation in a patient with intestinal blood loss is stressed.

Adult↗
PubMed2000

Phenolic constituents from Grevillea robusta.

Seven phenolic compounds were isolated from a MeOH extract of the leaves of Grevillea robusta. Their structures were determined by various spectral methods including 2D NMR spectroscopy.

Magnetic Resonance Spectroscopy↗
PubMed2000

Sesquiterpene lactone glucosides from Sonchus asper.

From the methanolic extract of the roots of Sonchus asper, two new sesquiterpene glucosides, together with two known sesquiterpene glucosides and a known aglycone were isolated. Structures were identified as 11beta,13-dihydrourospermal A, 15-O-beta-D-glucopyranosyl-11beta,13-dihydrourospermal A, 15-O-beta-D-glucopyranosylurospermal A, 15-O-[6'-(p-hydroxyphenylacetyl)]-beta-D-glucopyranosylurosperm al A and 14-O-methylacetal-15-O-[6'-(p-hydroxyphenylacetyl)]-beta-D-+ ++glucopyranosylurospermal A, by spectroscopic means.

Asteraceae↗
PubMed2000

Anti-HIV-1 phorbol esters from the seeds of Croton tiglium.

Five phorbol diesters, together with three known ones, were isolated from a MeOH extract of the seeds of Croton tiglium, and their structures were determined by spectroscopic methods and selective hydrolysis of acyl groups. These compounds were assessed for their abilities to inhibit an HIV-induced cytopathic effect (CPE) on MT-4 cells and to activate protein kinase C (PKC) associated with tumor-promoting action. 12-O-Acetylphorbol-13-decanoate and 12-O-decanoylphorbol-13-(2-methylbutyrate) effectively inhibited the cytopathic effect of HIV-1 [complete inhibitory concentration (IC100) values of 7.6 ng/ml and 7.81 microg/ml, and minimum cytotoxic concentration (CC0) value of 62.5 and 31.3 microg/ml, respectively]; however, 12-O-acetylphorbol-13-decanoate showed no activation of PKC at concentrations of 10 and 100 ng/ml. 12-O-Tetradecanoylphorbol-13-acetate (TPA) was found to be not only the most potent inhibitor of HIV-1-induced CPE (IC100 value of 0.48 ng/ml), but also the most potent activator of PKC (100% activation at 10 ng/ml).

Animals↗
PubMed2000

Expression of thyroid transcription factor-1 (TTF-1) in human C cells and medullary thyroid carcinomas.

Thyroid transcription factor-1 (TTF-1) has been known to regulate the transcriptional activity of thyroid-specific genes in thyroid follicular cells. We recently identified TTF-1 mRNA expression in rat thyroid C cells. The current study was undertaken to elucidate how TTF-1 is expressed in human C cells and medullary thyroid carcinomas (MTCs), and how this expression influences the functions and clinical behavior of these cells. By immunohistochemistry, the nuclei of normal and hyperplastic C cells distinctively reacted with antibody against TTF-1, whereas the immunostaining intensity in C cells was rather weak and heterogeneous in comparison with that in follicular cells. Identical TTF-1 immunoreactivity was observed in all 15 MTC specimens examined. The reaction intensity did not depend on tumor patterns or cell features. In nonisotopic in situ hybridization, an antisense riboprobe clearly hybridized the cytoplasms of C cells and MTC cells, which concurrently showed immunohistochemical positivity for calcitonin. Northern blot analysis indicated a marked hybridization with TTF-1 mRNA of approximately 2.3 kb in an MTC specimen. Furthermore, the presence of TTF-1 mRNA was confirmed by reverse transcription polymerase chain reaction (RT-PCR) in the human MTC cell line, TT. Our results suggest that human thyroid C cells and MTC cells express TTF-1 in connection with their functional ability. Therefore, TTF-1 expression can be a functional marker not only for follicular cells and follicular cell tumors but also for C cells and medullary C cell carcinomas.

Adolescent↗
PubMed2000

Crossline levels in serum and erythrocyte membrane proteins from patients with diabetic nephropathy.

Crossline is one of the structurally defined adducts of advanced glycation endproducts (AGEs) which has both a crosslink and fluorescence similar to AGE-protein in vivo. Crossline was measured in serum and erythrocyte membrane proteins (EMP) from 52 type 2 diabetic patients using a specific enzyme-linked immunosorbent assay system. Serum and EMP crossline levels in the diabetic patients were significantly higher than those in normal control. The patients with advanced diabetic nephropathy (serum creatinine levels of more than 1.2 mg/dl) had markedly elevated serum crossline levels compared to those with moderate diabetic nephropathy (clinical proteinuria) (180. 7+/-51.7 vs. 71.8+/-18.4 pmol/ml; P<0.01). On the other hand, there were no significant differences in EMP crossline levels between the two. EMP crossline levels in the patients with moderate diabetic nephropathy (8.8+/-2.9 pmol/mg protein) and those with advanced diabetic nephropathy (9.7+/-3.0 pmol/mg protein) were significantly higher than those without clinical proteinuria (6.4+/-1.9 pmol/mg protein; P<0.01). The present study demonstrated that EMP crossline levels were associated with the presence of nephropathy in patients with type 2 diabetes mellitus. Serum crossline levels were significantly influenced by remaining renal function. The measurement of crossline from a blood sample could provide us with important information for the study of clinical evaluation and pathogenesis of diabetic complications.

Aged↗
PubMed2000

Association between type 1 diabetes age-at-onset and intercellular adhesion molecule-1 (ICAM-1) gene polymorphism.

We investigated the intercellular adhesion molecule-1 (ICAM-1) gene polymorphism in 90 patients with young-onset type 1 diabetes, 74 with adult-onset type 1 diabetes, and 171 control subjects. The distribution of C-T genotypes and allele frequencies in exon 6 of the ICAM-1 gene was significantly different between adult-onset type 1 diabetes patients and controls (chi(2) = 9.76, p = 0.0076), and between patients with adult-onset and young-onset type 1 diabetes (chi(2) = 11.28, p = 0.0036). In contrast, we failed to detect any association between patients with young-onset type 1 diabetes and controls. Our data suggest that ICAM-1 exon 6 gene polymorphism affects the age-at-onset of type 1 diabetes and that different pathogenetic mechanisms may exist between young-onset and adult-onset type 1 diabetes.

Adolescent↗