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Biomedical subjects

T Ohmori

Publications and source records attributed to T Ohmori.

At least 235 records · Page 13Linked to original sources
PubMed1984

Enhancing effect on N-nitrosodimethylamine-induced tumorigenesis by unilateral hydronephrosis.

The effect of unilateral hydronephrosis (U-HN) on chemical tumorigenesis by two im injections of N-nitrosodimethylamine (DMN; CAS: 62-75-9) with the use of inbred female W rats was studied. Of the rats in the U-HN group, 70.0% developed kidney tumors, 25.0% developed mammary tumors, 20.0% developed hepatomas, and 20.0% developed other tumors. Almost all kidney tumors in the U-HN group (96.0%) were induced in the compensatory (contralateral) kidney. In contrast, of the rats in the unilateral nephrectomy (U-NR) group, 29.4% developed kidney tumors, 11.8% developed mammary tumors, 23.5% developed hepatomas, and 11.8% developed other tumors. Rats in the sham-operated group developed 1 small kidney tumor (7.7% of the rats) but no tumors in other organs. Thus, under these conditions, U-NR and especially U-HN strongly increased tumor induction in DMN tumorigenesis not only in the compensatory kidney but also in extrarenal organs.

Animals↗
PubMed1983

Solitary plasmacytoma of the submandibular lymph node with stromal amyloid deposits.

This report concerns a case of solitary extramedullary plasmacytoma of the left submandibular lymph node in a 56-year-old man. The tumor showed monoclonal proliferation of abnormal plasma cells which revealed highly positive stainings of both methylgreen pyronin and kappa light chain using the immunoperoxidase technique in the cytoplasms, and further revealed massive amyloid deposits in the stroma, which suggested the possibility of sequential amyloid formation upon the secretion of paraprotein by tumor cells.

Amyloid↗
PubMed1983

Milk of northern fur seal: composition, especially carbohydrate and protein.

The milk of northern fur seal was analyzed with special interest in carbohydrate and protein. High solids (61%) and fat (45.6%) were characteristics of its gross composition. Fatty acid distribution showed that more than 22% of the fatty acids had carbon chains longer than 20 and that approximately 70% contained one or more double bonds. Analysis of free sugars showed no lactose but 123 mg/100 ml of myo-inositol. In carbohydrates bound to casein, .99% of sialic acid and .2% of glucosamine were determined. The amino acid composition of casein showed higher tryptophan, lysine, serine, and glycine than bovine casein, and lower arginine, proline, and leucine. In whey, arginine, threonine, and valine were higher, whereas lysine, aspartic acid, isoleucine, and leucine were lower than in bovine whey. Amino acid patterns in casein and whey were similar to those of cat milk. The appearance of casein micelles was similar to bovine casein micelles. The mean diameter, however, was larger (approximately 330 nm). Electrophoretic pattern of casein showed five major bands in addition to minor components. One of the minor components was a glycoprotein, probably kappa-casein-like protein. The major whey protein had a mobility similar to that of bovine beta-lactoglobulin. No alpha-lactalbumin-like protein was observed.

Amino Acids↗
PubMed1983

Modulation of N-nitrosodimethylamine kidney tumorigenesis by unilateral hydronephrosis and multiple putrescine administrations.

The effects of unilateral hydronephrosis by ligation of the right ureter and/or multiple injections of putrescine on kidney tumorigenesis by a single intrarenal injection of N-nitrosodimethylamine (DMN) were studied. Inbred female W rats in the unilateral hydronephrotic groups given or not given putrescine developed kidney tumors and/or neoplastic or preneoplastic lesions of the liver at an incidence of 55.6%. Almost all kidney tumors developed in the contralateral kidneys, which showed hypertrophy due to unilateral hydronephrosis. Rats having unilateral hydronephrosis and subjected to long-term putrescine administration after DMN injection frequently contracted large mesenchymal cell tumors (83%), whereas the group not given putrescine developed no mesenchymal cell tumors. Histologically, epithelial cell tumors showed a marked decrease in both gamma-glutamyltransferase activity and trypan blue uptake, but mesenchymal cell tumors did not.

Animals↗
PubMed1983

High susceptibility of specific inbred colonies of rats to n-2-fluorenylacetamide-induced hepatocarcinogenesis.

N-2-Fluorenylacetamide(FAA)-induced hepatocarcinogenesis in three colonies of Wistar-strain rats was studied. Two specific inbred colonies of rats derived from a Wistar strain, normotensive rats of Wistar Kyoto colony (WKY) and spontaneously hypertensive rats separated from WKY (SHR), showed higher inductions of preneoplastic altered foci of basophilic cell type and hepatocellular carcinomas as compared to common closed colony rats of the same strain (CWR). After 7 weeks of 0.02% FAA-containing diet, preneoplastic foci in WKY were found 4.8 times more frequently and in SHR 2.5 times more frequently than in CWR. Most of the foci found in WKY (92.5% of the total number of foci) and in SHR (87.1%) were of basophilic cell type, whereas most of the foci in CWR (71.3%) were acidophilic. After 7 months of the diet, multiple hepatocellular carcinomas were found in most rats in WKY (87.5% of the total number of rats, 2.6/rat) and SHR (81.8%, 2.5/rat) as compared to CWR (14.3%, 0.14/rat). These data demonstrate that rats in specific inbred colonies possess even higher susceptibility to FAA than CWR, and the susceptibility is closely related to the higher incidence of basophilic foci.

2-Acetylaminofluorene↗
PubMed1982

Gamma glutamyl transpeptidase activity in carcinogen-induced epithelial lesions of rat kidney.

A marked decrease of gamma glutamyl transpeptidase activity in rat renal cell neoplasms and preneoplastic tubular lesions induced by exposure to carcinogens was demonstrated. The data suggest that rat renal cell tumorigenesis might require a transformation to fetal characteristics in enzymatic activity such as is found in rat liver cell tumorigenesis, although the nature of the change in activity is quite different. The findings also suggest that persistence of weak gamma glutamyl transpeptidase activity of renal tubular cells during tumorigenesis may provide a useful histoenzymatic marker and indicate a biological reversion of the membrane function during the process of renal cell tumorigenesis.

Adenocarcinoma↗
PubMed1982

An etiological study on renal adenomas: with some references to dysplastic tubular lesions and adenocarcinomas in autopsy and surgery cases.

An etiological study on renal adenomas with specific references to dysplastic tubular lesions and adenocarcinomas was made, concentrating on histopathological and statistical surveys. Seventy-two unilateral kidneys obtained at random in autopsy cases were examined macro- amd microscopically on the consecutive sliced sections. Adenomas were found frequently in the cortex of 15 cases (20.8%), and particularly dysplastic tubular lesions were considerably associated with adenomas and detected even more frequently in 26 cases (36.2%), whereas fibromas in the medulla of 8 cases (11.1%). Most of the adenomas (86.7%) were found in nephrosclerotic kidneys; i.e., in vascular nephrosclerosis (53.4%), chronic pyelonephritis (13.3%), and in end-stage kidneys. The morphological feature of adenoma cells were also confirmed in the dysplastic tubular epithelial cells. These data imply that long-term renovascular and/or renostromal damages may induce dysplastic tubular lesions and further act as important enhancing or promoting factors on adult renal oncogenesis from the cortical tubular epithelium.

Adenocarcinoma↗
PubMed1981

Histochemical characteristics of spontaneous and chemically induced hepatocellular neoplasms in mice and the development of neoplasms with gamma-glutamyl transpeptidase activity during phenobarbital exposure.

The histochemical characteristics of spontaneous hepatocellular neoplasms in mice of both sexes were examined and compared with those of hepatocellular neoplasms induced in female mice by administration of polycyclic aromatic hydrocarbon carcinogens as initiators with or without subsequent phenobarbitone treatment. Controls treated with phenobarbitone alone was also induced. Spontaneous neoplasms in the livers of mice rendered siderotic by subcutaneous iron injection were deficient in cellular accumulation of stainable iron. Glucose-6-phosphatase activity was deficient in the majority of spontaneous and induced neoplasms. ATPase activity was increase in about half of spontaneous and carcinogen-induced neoplasms but all induced neoplasms in mice treated with phenobarbitone showed deficient activity. Gamma-glutamyltransferase activity was present in very few of the spontaneous neoplasms or in the neoplasms induced in the absence of phenobarbitone administration. However, all induced neoplasms in the mice receiving phenobarbitone showed some degree of gamma-glutamyltransferase activity together with deficient glucose-6-phosphatase and ATPase activities. It is concluded that the histochemical characteristics of spontaneous or induced mouse hepatocellular neoplasms are variable and may be influenced by the inducing factors.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1981

Enhancement of hepatocarcinogenesis by sequential administration of chemicals: summation versus promotion effects.

A comparative study was made of the sequential administration of the liver carcinogen, diethylnitrosamine (DEN), or the liver tumor promoter, phenobarbital, given after the liver carcinogen, N-2-fluorenylacetamide (FAA). The effects of the second carcinogen on preneoplastic cellular lesions induced by the first carcinogen were comparable to the effects of the promoter. In addition, both sequential exposures enhanced the ultimate carcinogenic effect, although the combination of FAA followed by DEN resulted in a greater number of malignant neoplasms. Thus, enhancement of carcinogenesis by a second chemical cannot be used by itself as evidence of a promoting action. Approaches to the more precise definition of promoters include exclusion of genotoxicity, identification of epigenetic mechanisms and lack of a summation effect with administration prior to genotoxic carcinogens.

2-Acetylaminofluorene↗
PubMed1981

Confirmation of the development of multiple renal cell tumors in endstage/long-term hemodialysis kidney revealed typical acquired cystic transformation.

Histopathological study of the endstage kidney in a 50-year-old male who died after intermittent maintainance hemodialysis for 10 years was reported. At autopsy, both kidneys were contracted and characterized by grossly visible discrete multiple cysts. Histopathological study of consecutive sections of both kidneys revealed that these cysts were distributed throughout a completely disorganized parenchyma and were composed of dysplastic epithelial cells of different types and of structures, some of which revealed neoplastic transformation.

Humans↗
PubMed1981

A study of tobacco carcinogenesis XX: mastocytoma induction in mice by cigarette smoke particulates ("cigarette tar").

A significant incidence of cutaneous mastocytomas was observed in female mice of CAF1/J and ARS-HA (ICR) strains upon long-term application of cigarette smoke condensate suspensions ("tar"). The mastocytomas were not detected in control groups treated with acetone, benzo(a)pyrene (BaP), tetradecanoyl phorbol acetate (TPA), nor in mice treated once with an initiator dose of 75 mg 7, 12-dimethylbenz(a)anthracene (DMBA). The skin mastocytomas were constantly accompanied by diffuse dermal mast cell infiltration (DDMI), which was also seen in the tumor-free skin of the "tar"-treated mice. These results indicate that mastocytomas were induced by agents present in the cigarette smoke condensate. DDMI might be a precursor of mastocytomas.

Animals↗
PubMed1981

Effect of intestinal microflora and dietary fat on 3,2'-dimethyl-4-aminobiphenyl-induced colon carcinogenesis in F344 rats.

The effect of dietary fat and intestinal microflora on colon and small intestinal carcinogenesis was studied in weanling male F344 germfree and conventional rats fed semipurified diets containing low and high fat. At 7 weeks of age, all animals, except vehicle-treated groups, received weekly s.c. injections of 50 mg 3,2'-dimethyl-4-aminobiphenyl (DMAB) per kg body weight for 20 weeks. The DMAB- and vehicle-treated germfree and conventional rats fed high- and low-fat diets were autopsied 20 weeks after the last injection of DMAB. The incidence of colon, small intestinal, ear duct, and skin tumors was lower in germfree rats than in the conventional animals. The incidence and multiplicity of DMAB-induced colon tumors were higher in conventional rats fed the high-fat diet than in the conventional animals fed the low-fat diet; however, the tumor incidence did not differ significantly between the high- and low-fat-fed germfree animals. Dietary fat had no effect on the incidence of small intestinal tumors in both germfree and conventional rats.

Aminobiphenyl Compounds↗
PubMed1981

Carcinogenicity in Syrian golden hamsters of N-nitrosamines formed during nitrosation of spermidine.

Several N-nitrosamines are formed during the nitrosation of the polyamines, spermidine and spermine. Since these polyamines may represent a source for the endogenous or exogenous formation of N-nitrosamines, their major nitrosation products were assayed for carcinogenicity in male Syrian golden hamsters. Administration of N-nitroso-3-butenyl(2-propenyl)amine SC once a week for life at a dose of 300 mg/kg induced neoplasms mostly in the upper respiratory tract (nasal cavity, larynx, trachea). Lung microlithiasis (alveolar and bronchial) also developed in all these animals. In contrast, N-nitroso-3-butenyl(3-hydroxypropyl)amine and N-nitroso-4-hydroxybutyl(2-propenyl)amine induced neoplasms, primarily in the digestive tract, including the nonglandular stomach, cecum, colon, and adrenal gland.

Animals↗
PubMed1980

Alteration by phenobarbital of membrane-associated enzymes including gamma glutamyl transpeptidase in mouse liver neoplasms.

Administration of phenobarbital for 5 to 7.5 weeks to aged C3HfB/HeN mice with spontaneous liver tumors produced an enhancement of gamma glutamyl transpeptidase activity in the tumors and a decrease in glucose-6-phosphatase and adenosine triphosphatase activity. Discontinuation of phenobarbital feeding for 5.5 weeks resulted in the loss of gamma glutamyl transpeptidase activity in tumors. These findings of alterations in three membrane-associated enzymes indicate that phenobarbital produces substantial changes in the composition of cellular membranes which may be related to its promoting activity.

Adenosine Triphosphatases↗
PubMed1980

Absence of uniform progressive growth of long-term transplants of rat liver neoplastic nodules.

Fragments of normal rat liver and neoplastic nodules induced by feeding 0.02% N-2-fluorenylacetamide for 20 weeks were transplanted into the inguinal mammary fat pads of syngeneic rats. All animals were Charles River inbred male albino rats of the CDF strain derived from the F344 strain. Normal liver transplants and neoplastic nudule transplants were detected histologically in the transplant site up to 24 and 66 weeks of survival, respectively. Of 30 nodule transplants followed up to 121 weeks, only 1 neoplastic nodule developed progressive neoplastic growth. The tumor that arose in the transplant site from this nodule was a well-differentiated adenocarcinoma with mucin production. Thus rat liver neoplastic nodules lack the high frequency of progressive growth previously demonstrated for carcinomas.

2-Acetylaminofluorene↗
PubMed1980

Comparative carcinogenicity in F344 rats of the tobacco-specific nitrosamines, N'-nitrosonornicotine and 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone.

The tobacco-specific carcinogens, N'-nitrosonornicotine (NNN) and 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), were tested for carcinogenicity in F344 rats. Each nitrosamine in trioctanoin was administered by s.c. injection to 12 male and 12 female rats over a period of 20 weeks. The total dose of each nitrosamine was 3.4 mmol. The experiment was terminated after 12 months. NNK induced nasal cavity tumors in 83% of the males and in 83% of the females, liver tumors in 83% of the males and in 100% of the females, and lung tumors in 67% of the males and in 67% of the females. NNN induced nasal cavity tumors in 92% of the males and in 75% of the females. Only one liver tumor and no lung tumors were observed in the NNN-treated rats. These results indicate that, in the F344 rat, NNK is a more powerful carcinogen than is NNN.

Animals↗
PubMed1980

The persistence and phenotypic stability of transplanted rat liver neoplastic nodules.

Fragments of normal rat liver and nodular hepatocellular lesions produced by feeding rats 0.02% N-2-fluorenylacetamide for 20 weeks were transplanted into the inguinal mammary fat pad of syngeneic male rats. Five of 29 fragments of normal liver survived in the transplant site for up to 32 weeks after transplantation. Six of 20 nodules classified as neoplastic nodules and 2 of 5 with atypicality persisted and retained their morphologic abnormalities. Persisting fragments of normal liver accumulated iron when the recipient rats were iron-loaded by the feeding of 8-hydroxyquinoline and ferrous gluconate, but the nodule cells remained resistant to iron accumulation. Mitotic figures were present in nodule cells, but progressive growth did not occur. Four carcinoma transplants readily gave rise to tumors. Three of the tumors that developed in the transplant site from carcinomas were well-differentiated adenocarcinomas with mucin production. It was concluded that rat liver neoplastic nodules are phenotypically stable but differ from liver carcinomas in their biologic behavior in this system.

Adenocarcinoma↗