Biomedical subjects

N Nemoto

Publications and source records attributed to N Nemoto.

At least 91 records · Page 5Linked to original sources

PubMed1993

Cell-density-dependent expression of Cyp1a2 gene in monolayer-cultured adult mouse hepatocytes.

Expression of Cyp1a1 and Cyp1a2 genes was investigated in adult C57BL/6NCrj mouse hepatocytes for up to 5 days after transfer to monolayer culture. CYP1A1 mRNA was substantially induced by treatment with 3-methylcholanthrene during the observation period, independently of the seeded cell density. However, expression of CYP1A2 mRNA was dependent on cell density and was higher in cells cultivated at lower density. With increasing culture period the expression was decreased, so that only negligible levels were evident by day 5, and reduced expression of constitutive and induced CYP-1A2 mRNA became apparent earlier in more densely seeded cells. This was not related to differences in numbers of inducer molecules per cell. While mouse hepatocytes incorporated tritium-labeled thymidine under the given culture conditions, induction of expression of the two Cyp1a genes did not show any direct relationship with DNA synthesizing activity. These observations suggest some role for Cyp1a2 during changes in physiological state.

Animals↗

PubMed1993

Activation of Cyp1a1 and Cyp1a2 genes in adult mouse hepatocytes in primary culture.

Expression of Cyp1a1 and Cyp1a2 genes was investigated in adult C57BL/6NCrj mouse hepatocytes in primary culture for up to 5 days. When the cells were cultivated as monolayers on collagen-coated dishes, CYP1A1 mRNA species were prominently induced after treatment with 3-methylcholanthrene (MCA) throughout the observation period. Substantial induction of CYP1A2 mRNA by MCA was also observed at day 1 of cultivation, followed by a decrease to very low levels thereafter. In contrast, when cultivated on non-coated dishes, the hepatocytes formed multicellular aggregates (spheroids) and prominent induction of both mRNA species was found for up to 5 days. Constitutive expression of CYP1A2 mRNA in spheroid culture was maintained throughout the observation period, whereas that in monolayer culture decreased rapidly. The time-course of the induced CYP1A2 mRNA amounts after the treatment with MCA or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) followed the same pattern as that of CYP1A1 mRNA. Expressed amounts of CYP1A1 or CYP1A2 mRNA in spheroid culture were higher than or similar to the levels in the case of in vivo production, respectively. Induction of both mRNA species was also observed in hepatocytes from nonresponsive DBA/2NCrj mouse in spheroid culture, but the expressed amount after MCA treatment was far smaller than for C57BL/6NCrj cells, despite equivalent expression in the two strains after TCDD. Activities of aryl hydrocarbon hydroxylase (AHH) and acetanilide 4-hydroxylase (AAH) were elevated with either type of cultivation after treatment with MCA or TCDD. Ratios of AAH to AHH were not changed between the two cultures after 24 h treatment. However, the ratios in spheroid culture after 48 h treatment increased, whereas they did not change in monolayer culture. The present observations indicate that the spheroid culture is more suitable than the monolayer system for studying the mechanism of Cyp1a2 gene expression in adult mouse hepatocytes.

Animals↗

PubMed1993

[Roles of pathology laboratories on medical care service and quality assessment system for pathological diagnosis].

In practical medicine, pathologists provide highly specialized medical information (pathological diagnosis) to clinicians. Pathological diagnosis includes histopathology, cytology, intraoperative consultation (rapid diagnosis by frozen section) and autopsy service. In particular, histopathological diagnosis of biopsy specimens, nearly always gives a qualitative diagnosis to unknown pathological process, in other words, a final diagnosis. In addition, pathological diagnosis contributes to supporting medical audit. Thus it is quite important that to establish the quality assessment system for pathological diagnosis which is hard to be judged with the value.

Autopsy↗

PubMed1993

Appearance of tumorous phenotypes in goldfish erythrophores transfected with ras, src, and myc oncogenes and spontaneous differentiation of the transformants in vitro.

When goldfish erythrophores isolated from the skin by tissue digestion and centrifugation in a Percoll density gradient were transfected in a monolayer-culture with v-Ha-ras or v-src oncogene either singly or in combination with v-myc by means of calcium phosphate-DNA co-precipitation, there appeared a certain number of transformants manifesting a chromatoblast-like profile and tumorous phenotypes as seen in the capability for unlimited growth, and piling-up in a monolayer-culture or colony formation in semi-solid soft agar. After successive growth in vitro for longer than one month which was scarcely observed with the erythrophores, the vast majority of such transformants began to differentiate into erythrophores and ceased proliferation spontaneously. The onset of their differentiation was ascertained by the deposition of marker pteridine pigments. None of the transformants differentiated into melanophores or iridophores or other neural crest derivatives as seen in goldfish erythrophoroma cells. Little difference was observed in their transforming efficiency (0.2-0.3 transformants/micrograms DNA) between the combinations of oncogenes applied but a tendency was noted that cells transfected with ras or src in combination with myc developed the capacity to grow for a longer period and differentiated at a later stage than those transfected solely with ras or src. One cell line (ESM-1) derived from the erythrophores transfected with src/myc grew successively over nine months, indicating its acquisition of immortality. The expression of the transfected oncogenes in this cell line was examined in comparison with the erythrophoroma cells by Western and Northern blot analyses.

Animals↗

PubMed1993

[A case report of mediastinal teratoma complicated with cardiac tamponade].

A 10-year-old Japanese boy was admitted to our hospital with complaints of the sudden and severe chest pain having occurred when he caught a ball on his chest. A chest X-ray film and MRI made a diagnosis of cardiac tamponade caused by perforation into the pericardial sac of a mediastinal teratoma and pericardial drainage was carried out. Pericardial effusion showed cloudy yellow and CA 19-9 level in the effusion was 6, 538.2 U/ml. The tumor was extirpated after recovery of his general condition. The tumor was consisted of solid material (5 x 6 x 3 cm) and of cystic part (4 x 6 x 0.8 cm) involving of viscous yellowish fluid. Microscopic sections showed ulcer with bleeding, granulation and pancreatic tissue. Histopathological diagnosis was benign mature teratoma. Including this case, fourteen cases of mediastinal teratomas with cardiac tamponade have been reported and this is the youngest case. Pancreatic tissue were observed histopathologically in most cases and it was thought that autodigestion by digestive enzyme from pancreas was major cause of perforation of the tumor into the pericardial sac.

Cardiac Tamponade↗

PubMed1992

Altered regulation of Cyp1a-1 gene expression during cultivation of mouse hepatocytes in primary culture.

Alterations in Cyp1a-1 gene expression in adult C57BL/6 mouse hepatocytes were followed after transferring them to primary culture during the initial 5 days. Changing the medium to a fresh one was associated with considerable amounts of Cyp1a-1 gene mRNA with a peak at around 6 hr after the medium change, followed by a decrease to negligible levels 24 hr later. Treatment of hepatocytes with cycloheximide increased the medium change-associated mRNA expression, the levels being equivalent to those observed after treatment with 3.2-25.6 nM 3-methylcholanthrene plus cycloheximide. With increasing length of culture period, cycloheximide-aided enhancement of the medium change-associated mRNA transcription increased. Although the chemical alone did not induce Cyp1a-1 gene transcripts in hepatocytes at day 1 or 2 of cultivation, for which medium had been changed 24 hr previously, prominent induction of transcripts was evident at later periods, the levels being elevated in accordance with length of time in culture. To examine whether or not the mRNA transcribed under these culture conditions was translatable, the cells were treated with actinomycin D after washing out the cycloheximide, in order to inhibit degradation of the generated mRNA (Nemoto N and Sakurai J, Carcinogenesis 12: 2115-2121, 1991). After these procedures significant elevation of aryl hydrocarbon hydroxylase activity was observed in hepatocytes, the rise being well correlated with elevated levels of mRNA transcripts. The observations suggest that the Cyp1a-1 gene might be expressed at low levels during the initial phase of cultivation of mouse hepatocytes in primary culture. Whether this expression might be essential for mouse hepatocytes to adapt to culture conditions is unclear. The findings do suggest, however, that superinducibility of the gene expression after cycloheximide treatment might be a result of a regulatory mechanism operating after adaptation to culture.

Animals↗

PubMed1992

Differences in regulation of gene expression between Cyp1a-1 and Cyp1a-2 in adult mouse hepatocytes in primary culture.

The regulation of expression of Cyp1a-1 and Cyp1a-2 genes was investigated in adult C57BL/6NCrj mouse hepatocytes for up to 5 days after transferring to either monolayer or spheroid (multi-cellular aggregate) primary culture. The expression of 3-methylcholanthrene (MCA)-induced CYP1A1 mRNA remained high during the observation period under both monolayer and spheroid culture conditions. In contrast, while levels of CYP1A2 mRNA in spheroid culture were also appreciable throughout, they rapidly decreased in monolayer culture to become negligible. An increase in intracellular cyclic nucleotide content induced CYP1A1 mRNA in the later culture period in either spheroid or monolayer cultures. A significant elevation of both basal and MCA-induced 7-ethoxycoumarin-O-deethylase, and MCA-induced aryl hydrocarbon hydroxylase and 7-methoxyresorufin-O-demethylase activities was observed in the presence of intracellular cyclic nucleotide content-increasing agents, although the extent of enhancement far exceeded that expected from the scarce changes in MCA-induced CYP1A1 mRNA levels. Basal and MCA-induced CYP1A2 mRNA expression were not changed by altering intracellular cyclic nucleotide content. The level of CYP1A1 mRNA after MCA treatment was elevated in the presence of cycloheximide. Furthermore, with increasing culture time, addition of this agent caused expression of Cyp1a-1 gene in MCA-untreated cells. In contrast, the presence of cycloheximide did not increase constitutive or MCA-induced CYP1A2 mRNA. These observations indicate that expression of Cyp1a-1 and Cyp1a-2 genes may be regulated by different mechanisms.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1992

Three-dimensional reorganization of a cell line of papilla Vateri adenocarcinoma in various culture conditions.

SAV-I, a cell line derived from a well differentiated adenocarcinoma of Vater's papilla, was cultured under four different conditions using collagen gel matrices (type I collagen): 1) double-layered, 2) floating double-layered, 3) embedded, and 4) floating embedded, then observed by light and electron microscopy and immunohistochemistry. Under all four conditions, three-dimensional growth with tubules occurred. In particular, the floating double-layered condition, where the cells were cultured between two collagen gel layers, then floated onto the medium, was useful for showing cellular reorganization. The three-dimensional growth patterns observed in vitro closely resembled the in vivo growth of SAV-I cells transplanted into nude mice. Therefore, we conclude that the floating double-layered condition is useful for demonstrating the morphological characteristics of the parent cells of established cell lines, and should be advantageous for studies of the relationship between cellular morphology and function in vitro.

Adenocarcinoma↗

PubMed1992

Lung capillary endothelial cells produce and secrete urokinase-type plasminogen activator.

Bovine lung capillary endothelial cells (BLuEC) were isolated, and their ability to produce plasminogen activator (PA) in vitro was demonstrated. BLuEC secreted more than 10 times as much as urokinase-type PA (u-PA) as did bovine aortic, hepatic capillary and adrenal capillary endothelial cells, and lung fibroblasts. BLuEC secreted u-PA on both sides of the cell layer, the luminal surface, and the basic surface attached to the basement membrane. u-PA mRNA was detected in BLuEC by Northern blotting, but not in endothelial cells from other tissues and fibroblasts. These results suggest that BLuEC may contribute not only to the patency of lung vessels but also to the maintenance of alveolar functions through the production and secretion of u-PA.

Amino Acid Sequence↗

PubMed1992

[A study of intraoperative rapid frozen section diagnosis focusing on accuracy and quality assessment].

Accuracy of frozen section (FS) diagnoses was investigated in a consecutive series of 1129 intraoperative consultations. In our series, the correct diagnosis including clinically not serious minor errors was made in 96.9% of the cases. Whereas the accuracy ratio of FS diagnosis for unknown pathologic process decreased to 92.2%. Among all the types of tissues, central nervous system was shown to be the most frequently handled for FS, followed by lung/bronchus, breast, liver/biliary tract, lymph node and so forth. The requesting ratio of FS, on the other hand, tended to be high in the following specialties; neurosurgery (46.5%), thoracic surgery (19.0%), general surgery, (10.0%). Deferred diagnosis with a provisional diagnosis and misinterpretations in histology typing without serious clinical problem accounted for 2.7% and 3.1% respectively. Causes of erroneous diagnoses seemed to be multifactorial, such as inappropriate sampling, diagnosis on poor quality histology sections, lack of clinical information, lack of enough experience in FS practice of pathologists, or a combination of more than two of them, though inevitable cases showing minimal cytological and structural atypia were included. Intraoperative consultation by FS diagnosis is now essential to serve a good quality medication to patients. It is thus necessary that to establish a tight peer review system and also to provide an education program with regard to practice in FS diagnosis particularly for young pathologists.

Frozen Sections↗

PubMed1992

Pitfalls in the double labelling immunoelectron microscopy using one face of the grid.

We compared two procedures in the double labelling immunoelectron microscopic method of hormone-storing cells: one-faced and two-faced procedures. With the two-faced procedure we got convincing results consistent with morphological finding, while we often got false results with the one-faced procedure. By the misleading one-faced procedure, the cell storing any one hormone will be misinterpreted as a multihormone storing cell. Therefore, it is concluded that the two-faced method is safer for the double labelling immunoelectron microscopic study.

Amylases↗

PubMed1991

Preferential excision repair and non-preferential photoreactivation of pyrimidine dimers in the c-ras sequence of cultured goldfish cells.

The time courses of excision repair and photoreactivation of pyrimidine dimers induced by 254-nm UV were examined in the genome overall and in the c-ras sequence of RBCF-1 cells derived from a goldfish, by the use of UV endonuclease of Micrococcus luteus and alkaline agarose gel electrophoresis. Excision repair was more efficient in the ras sequence than in the genome overall, whereas no differences in efficiency of photoreactivation were detected. These results suggest that excision repair is affected by the accessibility of chromatin, while photoreactivation is not.

Animals↗

PubMed1991

Increase of CYP1A1 mRNA and AHH activity by inhibitors of either protein or RNA synthesis in mouse hepatocytes in primary culture.

Regulation of CYP1A1 gene expression in mouse hepatocytes from C57/BL6 strain in primary culture was investigated with respect to aryl hydrocarbon hydroxylase (AHH) activity and mRNA levels. Small amounts of the CYP1A1 gene transcripts were detected without the presence of any known AHH inducers but after medium change. Maximal level of expression was approximately 6-9 h after the procedure, followed by a decrease to an undetectable level 24 h later. After temporary treatment of hepatocytes for 10 h with cycloheximide, an inhibitor of protein synthesis, AHH activity measured 14 h later was at a normal low level, although medium-change-associated CYP1A1 mRNA were increased by cycloheximide treatment. However, if cells were treated with either actinomycin D, alpha-amanitin or cordycepin, which are inhibitors of RNA synthesis, after exposure to cycloheximide, prominent induction of AHH activity was observed, the levels being almost equal to those for hepatocytes treated with benz[a]anthracene, a potent AHH inducer. With the same experimental protocol benz[a]anthracene-induced AHH activity was enhanced approximately 4-fold. After washing out cycloheximide and/or benz[a]anthracene, the decrease in the mRNA amounts was delayed in the presence of actinomycin D and half amounts were found even 12 h later; while without actinomycin D they reduced with a half-life of 3-4 h. The observations indicate that CYP1A1 gene expression might be regulated at the post-transcriptional level with compensatory mRNA stabilization under conditions of blocked further production, resulting in elevation of AHH activity.

Amanitins↗

PubMed1991

Regulation of mouse P(1)450 gene expression in monolayer-cultured hepatocytes from responsive and non-responsive strains.

Regulation of P(1)450 gene expression in mouse hepatocytes from responsive (C57BL/6) and non-responsive (DBA/2) strains in primary culture was investigated with respect to aryl hydrocarbon hydroxylase (AHH) activity and P450 transcript levels. Although significant induction of AHH activity in C57BL/6 mouse hepatocytes after exposure to benz[aanthracene (BA) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was observed 24 h after the beginning of cultivation, the response was more prominent after longer periods. AHH induction in DBA/2 mouse hepatocytes by TCDD was also evident after 24 h treatment, but that by BA was delayed, only becoming significant after 3 days. Limited treatment with cycloheximide (CHI) for the initial 8 h affected AHH activity measured after 24 h; BA-induced AHH activity was decreased if the treatment started day 1 after seeding of the cells from either strain, whereas if started at day 3 the enzyme activities in hepatocytes from C57BL/6 strain were approximately doubled and those from DBA/2 increased to 130%. Treatment with dibutyryl cAMP or forskolin, a specific activator for adenyl cyclase, increased BA-induced AHH activities. 3-Methoxybenzamide, a specific inhibitor of poly(ADP-ribose) polymerase, significantly increased both basal and BA-induced AHH activities of hepatocytes from both strains at days 3 and 5, reduction of P(1)450 transcripts also being evident in the latter case. The observations indicate qualitatively similar but quantitatively different regulation of AHH induction in both responsive and non-responsive mouse strains. Furthermore the regulation changed with increasing cultivation period. Previously described regulation mechanisms in cultured cells were observed to operate a few days after seeding, possibly after adaptation of hepatocytes to the culture conditions.

Animals↗

PubMed1991

Ectopic retinoblastoma within the 3rd ventricle: case report.

Ectopic intracranial retinoblastomas are rare. These tumors usually occur in the pineal, parasellar, or suprasellar regions several years after the successful treatment of ocular retinoblastomas with no evidence of direct extension or distant metastasis. We report here a case of ectopic retinoblastoma occurring within the third ventricle. The tumor was surgically excised by the transventricular approach. Ectopic retinoblastomas exhibit greater differentiation than one would expect to observe in a metastatic lesion of this tumor. The distinction of ectopic retinoblastomas and metastasis from ocular retinoblastomas is important, since ectopic retinoblastomas, unlike metastasis, can be successfully managed by intensive therapy including radical excision.

Cerebral Ventricle Neoplasms↗

PubMed1991

Proline is required for transcriptional control of the aromatic hydrocarbon-inducible P(1)450 gene in C57BL/6 mouse monolayer-cultured hepatocytes.

Expression of aryl hydrocarbon hydroxylase (AHH) and the corresponding gene, Cyp1A1, or P(1)450 in mice, in C57BL/6 mouse hepatocytes in primary culture was investigated after exposure to benz[a]-anthracene with respect to proline-related metabolic regulation. When the cells were cultivated in complete Waymouth MB752/1 (Way), prominent induction of AHH by benz[a]anthracene was observed, whereas the induction was inefficient in the same but proline-deficient medium [Way-(-pro)]. Constitutive AHH activities decreased with increasing culture period. P(1)450 gene transcripts were slightly expressed when the medium was changed, independently of whether the cells were cultivated in either Way or Way(-pro), followed by decreased within 24 h and no apparent induction of AHH. However, treatment with delta 1-pyrroline-5-carboxylic acid (P5C), a biosynthetic precursor for proline, dose-dependently increased basal AHH activities in the cells cultivated in Way-(-pro). Benz[a]anthracene induction of AHH in cells cultivated in Way(-pro) was additively increased in the presence of P5C as much as with proline. Treatment with o-aminobenzaldehyde, which inactivates P5C, drastically reduced the induced AHH activities in hepatocytes cultivated in either P5C-added Way(-pro) or Way medium. Benz[a]anthracene induced both P(1)450 and P(3)450 mRNAs. Neither proline nor P5C increased the induced transcripts within 12 h after the start of benz[a]-anthracene treatment, but the two compounds increased the amounts of P(1)450 mRNA found at later time points. After treatment with actinomycin D, the half-life of the induced P(1)450 mRNA was approximately 12 h, being independent of the presence of either proline or P5C. Our observations suggest that induction of AHH after treatment with polycyclic aromatic hydrocarbon is dependent on proline-related metabolism which influences the transcriptional process of P(1)450 gene expression.

Animals↗

PubMed1991

Intradural extraosseous chordoma in the foramen magnum region. Case report.

Chordomas that are entirely extraosseous and intradural are extremely rare. The tumors described in the literature were observed mostly in the prepontine region. This is the first case reported of an intradural extraosseous chordoma occurring in the foramen magnum region. The tumor was totally excised. The distinction between an intradural extraosseous chordoma and a classic chordoma is important from a clinical viewpoint because of the potential for complete surgical excision and a more benign growth pattern.

Adult↗

PubMed1991

Small cell carcinoma of the uterine cervix showing Cushing's syndrome caused by ectopic adrenocorticotropin hormone production.

A uterine cervical cancer is reported in a woman who developed Cushing's syndrome. The tumor measured 1.3 x 0.7 cm, and was a pure small cell carcinoma, identical to that in the lung. The primary tumor cells showed argyrophilia with Grimelius staining and reacted positively to the anti-chromogranin antibody. Clinically, the neoplasm behaved in an aggressive manner in spite of adjuvant chemotherapy and radiotherapy, and the patient died of widespread metastasis. Cushing's syndrome was noted after the occurrence of liver metastasis with an elevation of the serum adrenocorticotropin hormone (ACTH) level. At autopsy, metastatic tumor cells from the liver reacted immunohistochemically positively not only to anti-ACTH but also to antichromogranin, anti-gastrin and anti-calcitonin antibodies. This is the first report of an immunohistochemical analysis of, and comparison of primary and metastatic sites in cervical carcinoma showing Cushing's syndrome.

ACTH Syndrome, Ectopic↗