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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Porcine and bovine strains of E. coli suspected to be enterotoxigenic, were tested for heat-labile enterotoxin (LT) production by means of a test measuring the stimulation of the synthesis of 3151 cyclic adenosin monophosphate (cAMP test) and rounding mouse adrenal tumor Y1 cells (Y1 test), and for heat-stable enterotoxin (ST) production by means of the baby mouse test (BM test). The test results were compared with those of the ligated gut test (LG test) using pig and calf intestine. One hundred and eleven strains of human origin were tested in the cAMP test, the Y1 test and the BM test. All strains were tested for the presence of the attachment factors K88, K99, P987 and CF10407. Seventy-four of 117 bovine strains produced only ST and all 74 ST-producing strains possessed K99 antigen. None of the 43 nonenterotoxigenic strains possessed K99. The presence of K99 antigen is therefore a reliable indicator of enterotoxigenicity in bovine strains. Porcine strains produced LT, ST or LT + ST. The K88 antigen was found in 52 out of 101 enterotoxigenic strains, K99 and P987 in 7 and 6 strains respectively and the latter 13 strains produced only ST. P987 was only detected after subculturing in liquid medium to enhance pilus formation. Eleven out of 111 strains of human origin stimulated cAMP synthesis but failed to round Y1 cells, whereas 4 known LT producers were positive in both tests. Attachment factors were found only in 2 of the latter 4 strains.
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PMID:Detection of enterotoxigenicity and attachment factors in Escherichia coli strains of human, porcine and bovine origin; a comparative study. 22 93

Inbred WF rats were inoculated with crude suspensions prepared from liver and gut tissue of 12- to 15-day fetuses of the same strain. Rats previously unsensitized to syngeneic embryonic tissue were inoculated with fetal material sc three times during exposure to 1, 2-dimethylhydrazine dihydrochloride (DMH), a gastrointestinal (GI) carcinogen in rodents. Properly timed immunization inhibited the development, growth, and metastasis of primary GI tumors. This effects was observed in both sexes; however, it was more prounced in male rats. Nine WF rats with DMH-induced carcinoma of the GI tract were inoculated sc with syngeneic fetal tissue. Of 9 rats, 7 rejected the embryonal tissue implants, which thus demonstrated the presence of a concomitant immune response to embryonic antigen(s). Two rats in which fetal tissue grew out to palpable nodules had multiple GI tumors with metastasis and extra-GI tumors, i.e., a massive tumor load. Ten other rats with DMH-induced GI tumors were treated with unblocking serum. The unblocking serum was inoculated to counteract serum-blocking factors in vivo. These rats were inoculated intradermally with syngeneic fetal tissue. In all 10 rats, inflammation and necrosis were noted at the inoculation site after 24-72 hours, which thus demonstrated a delayed hypersensitivity reaction to embryonic antigens. Our experiments suggest that embryonic antigens common to fetal and tumor cells can induce immunity in an autochthonous host and can act as rejection antigens.
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PMID:Effect of embryonic tissue immunization on chemically induced gastrointestinal tumors in rats. I. Can embryonic antigens act as rejection antigens? 27 25

Metastatic tumors from livers of 5 patients with gastrointestinal carcinomas and from the liver of 1 patient with malignant breast carcinoma were extracted with 3 M KCl; similar extracts were prepared from normal human colon and liver and from human fetal gut. The extracts were depleted of serum globulins by passage through reverse immunoadsorbent columns consisting of rabbit antibodies to the F(ab)2 fragment of human IgG and were then coupled to CNBr-activated paper disks. These "antigen" disks were used in a radioimmunoassay, with the aid of 125I-labeled rabbit antihuman F(ab')2 antibodies for the assay of circulating tumor antibodies produced by cancer patients. Statistical evaluation of the results with plasma samples from 47 patients with colorectal carcinomas and from 7 patients with other gastrointestinal disorders (polyps, villous papilloma, diverticulitis, and Crohn's disease) indicated that a significant number of patients had antibodies to cross-reactive tumor antigen(s). The cross-reactive tumor antigen(s) involved in the reaction was not detected in extracts of the gastrointestinal tract from 12-week human fetuses and did not cross-react with carcinoembryonic antigen.
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PMID:Detection of tumor antibodies in patients with gastrointestinal carcinomas by a solid-phase radioimmunoassay. 28 24

Thymidine, in the absence of hypoxanthine, failed to protect normal mice from the acute toxicity of methotrexate, though tumor-bearing animals could be protected with thymidine alone, probably as a result of the availability of DNA degradation products released from drug-sensitive tumor cells. Although metrotrexate induced an early purine deficiency in gut cells, this effect was not detected in bone marrow. Later, purine deficiency became apparent in the gut and bone marrow of methotrexate-treated animals.
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PMID:Some observations on the reversibility of methotrexate toxicity in normal proliferating tissues. 29 94

A number of powerful chemical compounds that modify radiation effects have been discovered and tested both in the laboratory and clinically over the past 25 years. There are four major classes of compounds: aminothiol radio-protectors which act on well vascularized euoxic cells and concentrate in tissues such as skin, gut and marrow; nitromidazole radiosensitizers which act on hypoxic tumor cells; pyrimidine analogues which are incorporated into the DNA of cycling cells and cause radiosensitization; and cancer themotherapy agents which, in addition to their ability to kill tumor cells directly, also may sensitize tumor and normal cells to radiation. The mechanism of action, experimental activity, and clinical results or the potential for each of these agents are reviewed.
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PMID:Chemical modification of radiation effects. 31 1

In colonic adenocarcinomata abnormalities have been noted in all morphological aspects of the local immune system of the bowel; thus, in such tumours there is a defective production of secretory IgA, a diminished content of secretory component (SC) and a marked decrease in intraepithelial lymphocytes. By contrast, no such abnormalities were noted in the non-neoplastic areas of the bowel, either immediately adjacent to, or some distance from, the carcinoma. These findings suggest that there is not usually any generalised morphological abnormality of the local immune systems in intestinal neoplasia and that the immunological abnormalities noted within the tumour are a result of the changed nature of the epithelium, thus altering, or interfering with, the normal interactions between epithelial and lymphoid tissue in the gut.
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PMID:Abnormalities of the local immune system in intestinal neoplasia: a morphological study. 32 43

Amygdalin at various concentrations and with numerous impurities is the most common cyanogenic glycoside found in laetrile samples. Its chemical properties were first described in 1837, and pharmacologic studies have shown that ultimately it is broken down to HCN, benzaldehyde, and glucose by enzymes found in gut bacteria but not intracellularly in humans. Fatal and nonfatal toxicities to orally ingested cyanogenic glycosides have been reported worldwide. We review here the signs and symptoms of acute cyanide toxicity and its treatment. Substantial in-vitro and in-vivo testing in animal tumor systems has shown that amygdalin is entirely devoid of significant anticancer activity. Control animals often have lived longer than those treated with various doses and schedules of amygdalin. Acceptable clinical studies in humans are lacking, but such ventures would appear to be contraindicated from animal studies and observed human toxicities. We also discuss current legal-judicial aspects of laetrile therapy for cancer.
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PMID:The current status of laetrile. 35 91

Two patients developed isolated Candida albicans peritonitis in association with intraabdominal malignancy. Although additional factors predisposing to the development of fungal peritonitis were present, we postulate that tumor-related local factors permitted fungi to cross the gut wall and to enter the peritoneum, where the host immune status determined whether the infection spread. These two cases are the sixth and seventh reported cancer patients who developed fungal peritonitis, but the first two who had the fungal infection localized to the peritoneum; and this is the first report known to us specifically associating intraabdominal malignancy and fungal peritonitis. Patients who develop fungal peritonitis may have a primary or metastatic intraabdominal malignancy, and fungi should be considered as a cause of peritonitis in cancer patients.
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PMID:Fungal peritonitis and malignancy: report of two patients and review of the literature. 37 52

The behavior of the activity of arginyl-tRNA synthetase (L-arginine : tRNAArg Ligase(AMP-forming), EC 6.1.1.19) was determined in extracts of rat liver: normal adult, normal proliferating (from developing and from partially hepatectomized rats), and neoplastic (hepatomas of different growth rates) and in extracts of rat kidney cortex and transplantable kidney tumors. The Km values for arginine, ATP, and tRNA of the enzyme of the rapidly growing hepatoma 3924A were the same as those of the enzyme from the liver of control rats. The pH optima of the control and neoplastic livers were in the same range of 7.25-8.0. Taking the hepatic specific activity for arginyl-tRNA synthetase as 100%, deep layer of gut, thymus and testis had higher activity; renal cortex and spleen had the same activity; and skeletal muscle, brain, heart, lung, superficial layer of gut and adipose tissue had lower activity. In a wide spectrum of hepatomas of different growth rates, a significant increase of 1.4-2.4-fold in arginyl-tRNA synthetase activity was observed when compared with that of liver of control normal rats. This elevation in enzyme activity in hepatomas appears to be specific to neoplasia, since it is unaltered in regenerating and low in differentiating liver. The increase in arginyl-tRNA synthetase in the liver tumors appears to be transformation-linked, since the activity was increased in all hepatomas, even in the slowest growing ones. Furthermore, the increase in enzyme activity was not limited to hepatic neoplasms, since a rise was also observed in transplantable rat kidney tumors. Thus, the reprogramming of gene expression in neoplastic tissue entails an increase in arginine-tRNA synthetase activity.
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PMID:Neoplastic transformation-linked alterations in arginyl-tRNA synthetase activity. 42 64

This study was designed to clarify the role of gut microflora in tumorigenesis by a comparison of tumor production between male germ-free and conventional Wistar rats given N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 100 microgram/ml in drinking water. Ninety-one % of conventional MNNG-treated rats that died or were killed by Day 314 of the experiment developed tumors in the gastrointestinal tract, whereas only 17% of germ-free treated rats developed such tumors. In addition, large tumors, some 5 cm or more in diameter, were frequently observed in the conventional rats, whereas only small tumors 0.4 to 1.2 cm in diameter were present in the germ-free rats. Furthermore, multiple tumors including double tumors were often found in the conventional rats, while such tumors never appeared in the germ-free rats. The results suggest that gut microflora might exert a promoting influence on tumorigenesis by MNNG in the gastrointestinal tract. The promoting influence of the microflora in conventional rats might not be of a simple nature, since the influence of a variety of factors modified by the micorflora on tumorigenesis by MNNG p.o. is unavoidable.
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PMID:Gastrointestinal carcinogenesis in germ-free rats given N-methyl-N'-nitro-N-nitrosoguanidine in drinking water. 44 76


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