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Biomedical subjects

A Yasui

Publications and source records attributed to A Yasui.

At least 145 records · Page 8Linked to original sources
PubMed1986

[Present diagnostic status of scirrhous type gastric cancer--with special reference to the endoscopic diagnosis].

First, we presented an actual diagnostic situation in nowadays for gastric cancer of Borrmann 4, which is virtually the same as scirrhous gastric cancer. Among 12 patients treated by the author, all of whom were discovered late, only 3 underwent surgery. In fact, with inoperable cases in Borrmann 4, even those endoscopically found to show insufficient stretching of the gastric wall, thickening and tortuosity of folds, uneven gastric mucosa, redness and white coating, there may be negative in gastric biopsy. However, the significance of an endoscopic examination for diagnosis of scirrhous cancer is in obtaining proof of the carcinoma (especially when still operable) by gastric biopsy. Thus, one must strive not to overlook slight redness, white coating which means small erosions, but to go over gastric biopsy again and again. Next, with carcinoma presenting a leather bottle (linitis plastica type) of the stomach itself, the II c portion of the stomach consisted of fundic glands (undifferentiated carcinoma) shall become the primary focus supporting Nakamura's theory. One case of diffuse invasive cancer, mistakenly diagnosed as a II c case, and two cases of regional type, one similar to II c and the other a Borrmann 2 carcinoma of advanced carcinoma showing strongly fibrous scirrhous tendency toward infiltration, were jointly monitored.

Adenocarcinoma, Scirrhous↗
PubMed1985

Expression of an Escherichia coli phr gene in the yeast Saccharomyces cerevisiae.

A 2 kb DNA fragment, containing the photoreactivation gene phr1 from Escherichia coli, was inserted at the BamH1 site in the tet gene of the yeast--E. coli shuttle vector pJDB207. Photoreactivation--deficient Saccharomyces cerevisiae cells transformed with this plasmid showed photoreactivation of killing after UV irradiation of the cells, while extracts of transformed cells exhibited photoreactivating activity in vitro. Far more photoreactivating enzyme molecules were found when the gene was inserted in the plasmid in the opposite orientation to the tet gene as compared with a plasmid carrying the inserted gene in the same orientation. Photoreactivating enzyme encoded by the E. coli phr1 gene and produced in transformed yeast cells has characteristics of the E. coli photoreactivating enzyme (flavoprotein) as judged from the influence of ionic strength on photoreactivating activity.

DNA Restriction Enzymes↗
PubMed1985

Microinjected photoreactivating enzymes from Anacystis and Saccharomyces monomerize dimers in chromatin of human cells.

Photoreactivating enzymes (PRE) from the yeast Saccharomyces cerevisiae and the cyanobacterium Anacystis nidulans have been injected into the cytoplasm of repair-proficient human fibroblasts in culture. After administration of photoreactivation light, PRE-injected cells displayed a significantly lower level of UV-induced unscheduled DNA synthesis (UDS) than non-injected cells. This indicates that monomerization of the UV-induced pyrimidine dimers in the mammalian chromatin had occurred as a result of photoreactivation by the injected PRE at the expense of repair by the endogenous excision pathway. Purified PRE from yeast is able to reduce UDS to 20-25% of the UDS found in non-injected cells, whereas the in vitro more active PRE from A. nidulans gives a reduction to only 70%. This suggests that the eukaryotic enzyme is more efficient in the removal of pyrimidine dimers from mammalian chromatin than its equivalent purified from the prokaryote A. nidulans.

Cells, Cultured↗
PubMed1985

Homology between the photoreactivation genes of Saccharomyces cerevisiae and Escherichia coli.

A cloned fragment of Saccharomyces cerevisiae chromosomal DNA carrying the photoreactivation gene (PHR) has been sequenced. The fragment contains a 1695-bp intronless open reading frame (ORF) coding for a polypeptide of 564 amino acids (aa). The phr gene of Escherichia coli was also sequenced, and the sequence is in agreement with the published data. The yeast PHR gene has a G + C content of 36.2%, whereas 53.7% was found for the E. coli gene. Despite the difference in G + C content there is a 35% homology between the deduced aa sequences. This homology suggests that both genes have originated from a common ancestral gene.

Amino Acid Sequence↗
PubMed1984

Significance of intestinal metaplasia for the evolution of cancer in the biliary tract.

Of 25 cases of cancer in the intrahepatic bile ducts, 44 cases of cancer in the extrahepatic bile ducts, 30 cases of adenoma in the gallbladder, and 100 cases of infiltrating carcinoma in the gallbladder, several to about 20% of the cases showed Paneth's cell metaplasia and/or enterochromaffin cell metaplasia within the tumor mass or in its surrounding mucosa. These metaplasia were not found in small adenomata of the gallbladder, but they were frequently seen in large adenomata. Goblet cell metaplasia and marked hyperplasia of mucous glands were seen more frequently in the mucosa surrounding cancer than in the mucosa of 500 non-neoplastic gallbladders. Although cancer in the gallbladder occasionally developed on the basis of intestinal metaplasia alone, intestinal metaplasia was not likely to be related to induction of most adenomata, but it was likely to be associated with growth and cancerous change of adenoma.

Adenoma↗
PubMed1984

Heterotopic gastric mucosa in the small intestine.

A case of tumorous heterotopic gastric mucosa which acted as a leading point of jejunal double-barrelled intussusception in a 16-year-old girl is presented. The lesion, 5 x 3 x 2 cm, was polypoid in shape with sharp circumscription. Histologically, the tumor consisted of gastric fundic and pseudopyloric glands. The pertinent literature is also reviewed.

Adolescent↗
PubMed1983

Effects of recB, recF and uvrA mutations on Weigle reactivation of lambda phages in Escherichia coli K12 treated with 8-methoxypsoralen or angelicin and 365-nm light.

The extent of Weigle reactivation (W-R) of lambda c+ phages treated with bifunctional 8-methoxypsoralen and 365-nm light (8-MOP + UVA) and with monofunctional angelicin and 365-nm light (ANG + UVA) were compared in Escherichia coli strains with different excision repair and recombinational capacities. In uvrA6 host cells, irradiation of the cells with 254-nm radiation only decreased the survival of phages treated with 8-MOP + UVA. The extent of W-R of ANG + UVA-treated phages in uvrA6 cells, however, was much larger than that obtained in other host cells. These results indicate that monoadducts produced by ANG + UVA treatment can be repaired effectively by the repair induced without uvrA gene products, but lesions produced by 8-MOP + UVA treatment cannot be repaired by the repair. The small W-R of ANG + UVA-treated phages in wild-type cells may be due to the high repairability of the lesions by constitutive excision repair in the cells. recB21 reduced only a little of the W-R of 8-MOP + UVA- or ANG + UVA-treated phages obtained in wild-type cells. Although recF143 cells have an almost comparable host-cell repair capacity of 8-MOP + UVA- or ANG + UVA-treated phages to that of the wild-type cells, recF143 mutation reduced not only the extent of W-R of 8-MOP + UVA-treated phages to 17% of that obtained in wild-type cells but also the extent of W-R of ANG + UVA-treated phages to 12% of that obtained in uvrA6 cells.

Bacterial Proteins↗
PubMed1982

Relation of adenoma to carcinoma in the gallbladder.

In order to clarify the relation of adenoma to carcinoma in the gallbladder, histopathologic examination was made on surgical specimens of 1605 cholecystectomies. Among them, 11 benign adenomas, seven adenomas with malignant change, and 79 invasive carcinomas were found. All of the benign adenomas were 12 mm or less in diameter (average diameter, 5.5 +/- 3.1 mm), while the adenomas having cancerous foci were 12 mm or more in diameter (average diameter, 17.6 +/- 4.4 mm). Most invasive carcinomas were more than 30 mm in diameter. The average patient age was 50.5 +/- 16.3 years for benign adenomas, 58.3 +/- 12.6 years for adenomas with malignant change, and 64.8 +/- 9.6 years for invasive carcinomas. Transition of benign adenoma into carcinoma was histologically traceable. Adenomatous residue was found in 15 (19.0%) of 79 cases of invasive carcinoma.

Adenoma↗
PubMed1981

UV-induced reactivation and mutagenesis of lambda-phages after treatment with 8-methoxypsoralen or thiopyronine and light.

Lesions, which were produced on lambda-phages DNA by the photosensitization effect of 8-methoxypsoralen (8-MOP) can be repaired by UV-induced repair systems (W-reactivation) in Escherichia coli wild type host cells. By optimum induction of the repair system, about 45% of the 8-MOP lesions are repaired. The survival of lambda-phages inactivated by the photodynamic action of thiopyronine (TP) is only negligibly increased by the same UV-induced repair systems. However, the frequencies of clear plaque mutations of 8-MOP treated as well as TP treated lambda-phages increase in similar fashion if the host cells of wild type have been irradiated with UV. These results show the different capacities of induced repair systems in repairing different types of lesions. They also suggest that some types of base damages are repaired more error-prone than other DNA-lesions.

Bacteriophage lambda↗
PubMed1979

Gastric carcinoma in dogs produced by the combined use of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) and gastrin--with special reference to development of scirrhous carcinoma.

Eight beagle dogs of four-month-old received both oral administration of N-Ethyl-N'-Nitro-N-Nitrosoguanidine (ENNG) and subcutaneous injection of gastrin, and one of them was found to have an annularly infiltrating advanced carcinoma with marked fibrous thickening of the antral wall resulting in stenosis of the antrum (carcinoma scirrhosum) which resembled "Linitis plastica" (Borrmann's type IV carcinoma) in human stomach.

Adenocarcinoma, Scirrhous↗
PubMed1977

Adenocarcinomas of the stomach induced in beagle dogs by oral administration of N-ethyl-N'-nitro-N-nitrosoguanidine.

Two 8-month-old and two 4-month-old male beagle dogs received 250 ml of 150 microgram/ml solution of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) and 2% Tween 60 mixed with a pellet diet twice a day for 8 months as the same methods used for mongrel dogs in our first report [Juntendo Medical Jouranl 19, 579-583 (1973)]. Gastric carcinomas with distant lymph nodes metastases occurred in three beagle dogs except for one died from anesthesia at the endoscopy. Metastases to the liver were observed in two beagles. In the most long-lived beagles, peritonitis carcinomatosa with ascites and metastases to the liver, lungs, bones, and skin were found. Main gastric tumors were located at the subcardia in two dogs (elevated tumor in dog No. 6, ulcerated tumor in dog No. 8), but in dog No 7 at the angulus (ulcerated tumor). Histologically, carcinomas were composed of poorly differentiated adenocarcinoma, signet-ring cell carcinoma, tubular adenocarcinoma, and undifferentiated adenocarcinoma. In all of three dogs which developed adenocarcinoma of the stomach, Stewart's criteria were completely satisifed. Using our methods the target organ is limited only to the stomach, without any sarcomatous lesion of the intestines.

Adenocarcinoma↗
PubMed1975

Determination of the number of photoreactivating enzyme molecules per haploid Saccharomyces cells.

Two haploid radiation-sensitive mutants of Saccharomyces were studied to investigate the formation of complex between photoreactivating-enzyme and substrate after ultra-violet irradiation. Using photo-flashes, the time necessary for maximum complex formation has been determined. Within 1 min, 70 per cent of the complexes have been formed. To determine the number of photoreactivating enzyme molecules per cell, the maximum dose decrement obtained after one photo-flash was determined and corrected for the effects of non-photoreactivable lesions. The corrected maximum dose decrement was found to be identical for both strains (8-5 erg mm-2). The number of photoreactivating-enzyme molecules involved in the photorepair of nuclear DNA damage was calculated as 272 +/- 27.

Cell Survival↗