Biomedical subjects
Publications and source records attributed to T Nikaido.
The structure of isohelianol isolated from the seeds of Camellia sasanqua Thunb. was established to be 3,4-seco-19(10-->9)-abeo-8alpha,9beta,10alpha-eupha-4,24-dien-3-ol (1) on the basis of spectroscopic methods.
A case of a yolk sac tumor (YST) with an ovarian endometrioid adenocarcinoma arising from endometriosis in a postmenopausal woman is described. Clinically, the case showed an aggressive course and did not respond to chemotherapy; the patient died of her disease 6 months after the operation. Histologically, the tumor consisted predominantly of an endometrioid adenocarcinoma, but it also showed microscopic features characteristic of YST. The tumor also contained benign endometriotic lesions with direct transition to the endometrioid adenocarcinoma. Immunohistochemical study revealed that not only the YST, but also the endometrioid adenocarcinoma was partly positive for alpha-fetoprotein. There was an inverse relationship between the endometriosis and the endometrioid adenocarcinoma in terms of the expression of sex steroid receptors and p53: adenocarcinoma cells were positive for p53 but negative for sex steroid receptors, whereas endometriotic epithelial cells were positive for sex steroid receptors but negative for p53.
Four novel triterpenoid saponins were isolated from the seeds of Vaccaria segetalis. Their structures were established as vaccaroside A, gypsogenic acid-28-O-beta-D- glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6)-[beta-D- glucopyranosyl-(1-->3)]-beta-D-glucopyranoside; vaccaroside B, gypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->2)-[3-hydroxyl-3- methylglutaroyl-(1-->6)]-beta-D-glucopyranosyl-(1-->6)-[beta-D- glucopyranosyl-(1-->3)]-beta-D-glucopyranoside; vaccaroside C, 23-O-beta-D-glucopyranosyl-gypsogenic acid-28-O-beta-D- glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6)- [beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside and vaccaroside D, 3,4-secogypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->3)- [beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside by a combination of extensive NMR (DEPT, COSY, HOHAHA, HETCOR, HMBC and NOESY) studies and chemical degradation.
Four new triterpenoid saponins, vaccarosides E, F, G and H were isolated from the seeds of Vaccaria segatalis and were respectively defined to be 3-O-beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl] quillaic acid 28-O-beta-D-xylopyranosyl-(1-->4)-chi-L-rhamnopyranosyl-(1-->2)- [chi-L-arabinofuranosyl-(1-->3)]-beta-D-4-O-acetylfucopyranoside; 3-O-[beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl] 3beta,4chi,16chi-trihydroxy-23-norolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-(1-->4)-chi-L-rhamnopyranosyl-(1-->2)- [chi-L-arabinofuranosyl-(1-->3)]-beta-D-4-O-acetylfucopyranoside; 3-O-[beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl] gypsogenin 28-O-beta-D-xylopyranosyl-(1-->4)-chi-L-rhamnopyranosyl-(1-->2)- [chi-L-arabinofuranosyl (1-->3)]-beta-D-4-O-acetylfucopyranoside; and 3-O-[beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl] 3beta,4chi-dihydroxy-23norolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-(1-->4)-chi-L-rhamnopyranosyl-(1-->2) -chi-L-arabinofuranosyl-(1-->3)]-beta-D-4-O-acetyfucopyranoside. Their structures were established on the basis of extensive NMR (DEPT, COSY, HOHAHA, HETCOR, HMBC AND NOESY), FAB-MS and ESI-MS studies as well as chemical strategies and enzymatic degradation. The new aglycones of two of the saponins have been designated as segetalic acid and vaccaric acid, respectively.
Twenty-eight picrotoxane terpenoids, including picrodendrins isolated from the Euphorbiaceae plant, Picrodendron baccatum (L.) Krug and Urban, have been evaluated for their ability to inhibit the specific binding of [3H]EBOB, the noncompetitive antagonist of ionotropic GABA receptors, to rat-brain and housefly (Musca domestica L.)-head membranes. Picrodendrin Q was the most potent competitive inhibitor of [3H]EBOB binding, with IC50 values of 16 nM (rat) and 22 nM (Musca). We find that the spiro gamma-butyrolactone moiety at the 13-position, which contains a carbonyl group conjugated with an unsaturated bond, and the substituents at the 4-position play important roles in the interaction of picrodendrins with their binding site in rat receptors. In contrast, such structural features are not strictly required in the case of the interaction with Musca receptors; the spiro saturated gamma-butyrolactone moiety at the 13-position, which bears the 16-sp3 carbon atom, and the hydroxyl groups at various positions are somewhat tolerated. Quantitative structure-activity studies have clearly shown that the electronegativity of the 16-carbon atom and the presence or absence of the 4- and 8-hydroxyl groups are important determinants of the potency of nor-diterpenes in Musca receptors, while the negative charge on the 17-carbonyl oxygen atom is likely important in the case of rat receptors. These findings indicate that there are significant differences between the structures of the complementary binding sites in rat GABA receptors and Musca GABA receptors. We also infer differences between native Musca GABA receptors and the Drosophila Rdl subunit-containing homo-oligomeric GABA receptors in the structures of their binding sites.
Two major triterpenoid saponins, named saponariosides A and B, were isolated from the whole plants of Saponaria officinalis and were respectively defined to be 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-be ta-D-glucuronopyranosyl quillaic acid 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha- L-rhamnopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)-beta-D-4-O-ac etylquinovopyranosyl-(1-->4)]-beta-D-fucopyranoside (1); 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-be ta-D-glucuronopyranosyl quillaic acid 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha- L-rhamnopyranosyl-(1-->2)-[beta-D-4-O-acetylquinovopyranosyl-(1-->4)] -beta-D-fucopyranoside (2). Their structures were established on the basis of extensive NMR (DEPT, DQF-COSY, HOHAHA, HETCOR, HMBC, and NOESY) and MS studies as well as chemical degradation.
The aim of the present study was to gain a better understanding of the localization of apoptotic cells within the human endometrium during the menstrual cycle and to elucidate the relationships among the following for the human endometrium: apoptosis, p21 expression, and cell proliferation. Apoptosis and p21 expression were identified mainly in the glandular cells of the basal layer in the late secretory phase. In contrast, cells positive for Ki-67 were observed predominantly in the functional layer (in the proliferative phase in glandular cells and in the secretory phase in stromal cells). A very strong positive correlation (r = 0.81; P < 0.001) was demonstrated between the number of apoptotic cells and the number of p21-positive cells present among the glandular cells but, topographically, individual apoptotic cells were not coincident with p21-positive cells in serial sections. The results of this study suggest that the proliferation of the glandular cells of the basal layer is regulated by both apoptosis and p21 expression, particularly in the late secretory phase. Such regulation may be necessary to maintain a healthy population of glandular cells in the basal layer of the endometrium.
A cyclin-dependent kinase (cdk) inhibitor, p27Kip1 (p27), binds to the cyclin E-cdk2 complex and functions as a suppressor of cell cycle promotion. Here, the involvement of p27 in the growth of normal human endometrium was immunohistochemically studied, and the findings were compared with those of Ki-67, cyclin E and cdk2. In addition, to elucidate the effect of progesterone on the expression of p27, tissues from patients with endometrial hyperplasia were examined before and after the administration of medroxyprogesterone acetate (MPA) for the treatment of this disease. In the glandular cells of the normal endometrium, p27 was negligible during the proliferative phase, whereas it was markedly increased in the secretory phase. The staining pattern of Ki-67 was the reverse. Cyclin E/cdk2-positive cells were observed throughout the menstrual cycle. In the secretory phase, the cyclin E/cdk2-positive cells were also positive for p27, suggesting an interaction between these molecules. Stromal cells, especially in the basalis, showed a consistent expression of p27 throughout the menstrual cycle. The expression of p27 in hyperplastic epithelia before the MPA treatment was negligible, whereas it was greatly increased after the treatment. The Ki-67 positivity decreased after the treatment. These findings suggest that p27 is involved in the progesterone-induced growth suppression of normal and hyperplastic endometria.
Intermediate trophoblast (IT) rarely gives rise to a placental site trophoblastic tumor (PSTT) To examine the different growth mechanisms present in normal and neoplastic IT, the expression of cell cycle regulatory molecules was compared at normal implantation sites and in PSTTs. Normal implantation sites in early gestation (19 patients) and PSTTs (6 patients) were immunohistochemically studied using antibodies against cytokeratin, human chorionic gonadotropin, and human placental lactogen to identify IT, and antibodies against Ki-67, cyclins (A, B, D1, and E), cyclin-dependent kinases (cdks), and p53 to investigate the proliferative activity of the trophoblast. Marked proliferative activity was observed in the trophoblast of the cell columns. Normal IT exhibited a very low labeling index for Ki-67, with negative expression for cdks and cyclins, except for cyclins B and E. The tumor cells of PSTT exhibited a high labeling index for Ki-67 with positive expression for all the cyclins and cdks examined. Expression of p53 was identified in tumor cells of PSTTs and the distribution of p53-positive cells correlated topographically with that of the cyclin A-positive cells. The transformed IT of PSTT has high proliferative activity with an abnormal expression of cell cycle regulatory molecules, which is not observed in normal IT.
Mast cells (MCs) have been reported in the myometrium and uterine smooth muscle tumors. We examined the number of MCs in various uterine smooth muscle tumors (including leiomyosarcomas) and assessed whether this feature might be of value in their pathologic diagnosis. The number of MCs in 95 uterine smooth muscle tumors, including 55 ordinary leiomyomas, 17 cellular leiomyomas, 8 bizarre leiomyomas, and 15 leiomyosarcomas, was counted using toluidine blue and immunohistochemical staining. The number of MCs that stained for tryptase was lowest in leiomyosarcoma and next lowest in ordinary leiomyoma; the number in each of these two groups was significantly lower than in the myometrium (p < 0.001). In cellular and bizarre leiomyomas, the number of MCs was significantly higher than in ordinary leiomyoma (p < 0.001 and p < 0.001, respectively) and leiomyosarcoma (p < 0.001 and p < 0.005, respectively). Statistical analysis revealed that counting the number of MCs and using a cut-off value of 16 MCs per high-power-field is useful for the differential diagnosis of leiomyosarcomas from cellular leiomyoma and bizarre leiomyoma, yielding 100% sensitivity and 96% specificity. The number of MCs was significantly lower in leiomyosarcomas at TNM stages III and IV than in those at stages I and II (p < 0.05), but there was no significant correlation between the number of MCs and patient survival. These results suggest that the number of MCs might be useful as part of a multivariate approach to the differential diagnosis of leiomyosarcoma from bizarre or cellular leiomyoma.
A universal inhibitor of cyclin-dependent kinases, WAF1/Cip1 can dephosphorylate the RB gene product to arrest the cell cycle at the G1 phase. Here we show that the mRNA level and the promoter activities of the RB and WAF1/Cip1 genes exhibit cell cycle-dependent change when cells are released from either serum-starvation or the confluent cell state with serum. RB expression and promoter activity are elevated at middle to late G1. In contrast, the mRNA and promoter activity of the WAF1/Cip1 gene increase at early G1. These results suggest that the RB and WAF1/Cip1 expression and promoter activities depend not only on serum, but also on the cell cycle progression itself. Moreover, we identified the responsive region for serum-released cell cycle progression in the RB promoter and mapped it to the region between -4 and -182 relative to the initiating codon of the RB gene. The region in the WAF1/Cip1 promoter responsible for the serum-released cell cycle progression mapped not to the p53 binding site, but to the 374 base-pair region between -1770 and -1396 from the transcription start site.
A new subculture method and a novel microplate assay for nematocidal activity using a species of Diplogastridae have been developed. The assay gives results rapidly, with high sensitivity in 4 h, and indicated good correlation between action mechanism and the nematode shape when examining 15 known compounds, including the antiparasitic avermectin, antimalarial quinine, and the gamma-amino-n-butyric acidA (GABAA) activated Cl- channel antagonist picrotoxinin. Thus new assay could be used as a primary screening method for new nematocidal compounds.
PURPOSE: To investigate whether cell cycle-related genes play a role in neuronal cell death in retinal ischemia-reperfusion injury. METHODS: Retinal ischemia-reperfusion injury was induced in rats by a ligation method and also by increasing the intraocular pressure. After 1 hour-of ischemia, cell death in the retina was studied using the TdT-dUTP terminal nick-end labeling (TUNEL) method, propidium iodide (PI) staining, DNA ladder formation, and ultrastructural studies. Immunohistochemical studies using antibodies against cell cycle-related genes were conducted. Changes in expression of cyclin D1 mRNA were quantitated using competitive quantitative polymerase chain reaction. RESULTS: At 3 hours after reperfusion, cells in the ganglion cell layer were the first to die, followed by those in the inner nuclear layer (at 6 hours) and outer nuclear layer (at 9 hours). Ultrastructural studies revealed condensed nuclei and relatively preserved mitochondria; DNA ladder formation was also detected. Immunostaining was positive for the cell cycle-related gene products c-Jun, cyclin B1, and cyclin D1. The time course of TUNEL-positive cells and that of cells positive for c-Jun or cyclin D1 in the inner nuclear layer was similar. A double-labeling study, using PI or TUNEL, and immunohistochemical analysis revealed that dying cells expressed c-Jun and cyclin D1, whereas cyclin B1 expression was observed in Müller cells. Quantitation of cyclin D1 mRNA revealed an approximate 4-fold increase at 24 hours after reperfusion. CONCLUSIONS: Aberrant expression of cell cycle-related genes may play an important role in the cell death that accompanies retinal ischemia-reperfusion injury.
To determine the genetic differences between various smooth muscle tumors of the uterus, the expression of calponin h1 (cytoskeletal protein) was examined in normal myometrium and in smooth muscle tumors of the uterus (leiomyosarcoma, smooth muscle tumors of uncertain malignant potential, cellular leiomyoma, bizarre leiomyoma, and ordinary leiomyoma) using immunohistochemistry and Western blotting. Analysis of calponin h1 transcripts using the reverse-transcription-PCR was also performed. Immunohistochemically, calponin h1 was expressed in normal myometrium and in all leiomyomas; however, its expression was markedly weaker in leiomyosarcoma. The results of both Western blotting and the analysis of calponin h1 transcripts were compatible with the immunohistochemical results. It is suggested that reduced expression of calponin h1 is associated with leiomyosarcoma of the uterus, and that calponin h1 expression may serve as a valuable molecular maker in the differential diagnosis of smooth muscle tumors of the uterus.
BACKGROUND: Abnormalities in G1 cell cycle regulation have been associated with the malignant transformation of cells. To obtain further information about the role of factors regulating the G1 cell cycle in the development of endometrial carcinoma, the authors analyzed the expression of cdk4 (cyclin-dependent kinase) and p16INK4 (an inhibitor of cdk4). METHODS: Immunohistochemical staining was performed on 20 specimens of normal endometria and 41 specimens of endometrioid-type endometrial carcinoma using antibodies against cdk4 and p16INK4. RESULTS: In the glandular epithelia of the normal endometria, cytoplasmic staining of cdk4 and p16INK4 was observed only in the proliferative phase, but nuclear staining of these agents was negligible. In endometrial carcinomas, 8 (19.5%) and 14 (34.2%) were positive for cdk4 and p16INK4 in the nucleus, respectively. Topographically, the nuclear cdk4 positive tumor cells were negative for p16INK4 and the nuclear p16INK4 positive tumor cells were found in areas without nuclear cdk4 expression, suggesting an inverse correlation between the two agents. In addition, the poorly differentiated carcinomas were more frequently positive for nuclear cdk4 than were the highly differentiated carcinomas (P = 0.03). CONCLUSIONS: These data suggest that increased expression of nuclear cdk4 associated with loss of p16INK4 expression could be involved in the carcinogenesis of a subset of endometrial carcinomas.
We analyzed the promoter activity of murine bone morphogenetic protein-4 (mBMP-4) and determined that the 5'-flanking region of exon I plays a critical role for transcription and position -265 to -246 of 5'-flanking region of mBMP-4 gene acts as a cis-element important for the regulation of BMP4 transcription in MC3T3E1 cells. By use of site-directed mutagenesis, we have established that the E-box, CACGTG, located within this short region of promoter, is essential for transcriptional activation of the mBMP-4 gene. Upstream stimulatory factor (USF), a member of the helix-loop-helix (HLH) group of regulatory proteins, was found to bind to this E-box using supershift gel mobility analysis. It is proposed that the HLH transcription regulatory proteins play an important role in mBMP-4 gene transcription in this osteoblastic cell line.
Effective chemotherapy for pancreatic cancer is urgently needed. The anti-proliferative activity of a new retinoid, mofarotene (RO40-8757), was compared with that of other retinoids, such as all trans-retinoic acid, 13-cis retinoic acid and 9-cis retinoic acid, on 9 pancreatic cancer cell lines in relation to the effects on various cell cycle-regulating factors. After treatment with each retinoid, anti-proliferative effect was determined by the MTT method and expression of cell cycle-regulating factors, such as cyclins (D1, E and A), cyclin-dependent kinases (2 and 4), cyclin-dependent kinase inhibitors (p21 and p27) and retinoblastoma protein, was analyzed by Western blotting. Mofarotene showed half-maximal inhibition of cell proliferation at concentrations between 0.14 x 10(-6) and 3.8 x 10(-6) mol/l with little cytotoxicity. In contrast, the other retinoids did not inhibit the growth of all cell lines by over 50% compared to controls. A marked increase in the fraction of cells in G1 phase of the cell cycle was observed after mofarotene treatment; this was associated with marked up-regulation of p21/p27 and a shift of retinoblastoma protein into the hypophosphorylated form. In conclusion, mofarotene inhibits the growth of pancreatic cancer cells by inducing G1-phase cell cycle-inhibitory factors (p21, p27 and hypophosphorylated form of Rb protein) and is considered to be a useful agent for pancreatic cancer treatment.
BACKGROUND: Mucinous tumors of the ovary have been thought to originate in two ways: by müllerian-type metaplasia of surface epithelium, and as monodermal teratomas. To gain a better understanding of their pathogenesis, the authors analyzed these tumors for their expression of estrogen receptors (ER) and progesterone receptors (PR) as markers of müllerian-type differentiation and for their content of gastric-type mucin as a marker of gastric differentiation. METHODS: The histochemical expression of ER, PR, and gastric-type mucin was studied in 10 specimens of the cervix with normal endocervical glands (as a representative of müllerian-derived mucin-containing cells), 3 ovary specimens with surface epithelial inclusion cysts that contained endocervical-like mucin-containing cells (representing müllerian-type metaplasia), and 47 mucinous tumors of the ovary (29 benign, 8 with low malignant potential, and 10 malignant). RESULTS: Normal endocervical glands expressed ER and PR and rarely expressed gastric-type mucin. Ovarian inclusion cysts showed strong expression of ER and PR in the cuboidal cells and drastically reduced expression in the endocervical-like mucin-containing cells. The cuboidal cells were negative for gastric-type mucin, but the endocervical-like mucin-containing cells expressed gastric-type mucin. Endocervical-like mucinous cells in benign and borderline mucinous tumors showed expression of PR and/or gastric-type mucin in all cases. CONCLUSIONS: The staining results for the inclusion cysts support the thesis that the endocervical-like mucinous cells encountered in the ones that express ER and PR weakly or not at all and have histochemical properties of normal gastric epithelium have their origin in metaplasia of müllerian-type epithelium. Application of the same staining methods to benign ovarian tumors and those with low malignant potential suggests strongly that similar müllerian-type metaplasia is a major pathway in their pathogenesis.