Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The parameters which influence the in vitro cytotoxicity of positively charged liposomes for L 1210 cells were analyzed. The cytotoxicity was liposome/cell ratio-dependent. It also depended upon the mole fractions of stearylamine (SA) to phosphatidylcholine (PC). There was no difference between the cytotoxicity of unilamellar and multilamellar vesicles but the cytotoxic effect of free SA was about 4 times greater than that of liposome incorporated SA at a molar ratio of 1:4, SA:PC, respectively. The process which resulted in cell death was irreversible after 60 min of cell-liposome contact. The simultaneous presence of neutral liposomes or of positively charged liposomes with a lesser charge density decreased the cytotoxic effect of liposomes with a higher SA content. The cytotoxicity could be decreased by trypsinization of cells following exposure to liposomes while treatment of cells with trypsin prior to the exposure to positively charged liposomes had no effect on the subsequent cytotoxicity. The cytotoxicity was also decreased if cells were incubated in the presence of sodium azide. The usual concentration of serum (10%) present in the growth medium had no effect on the cytotoxicity while preincubation of cells with liposomes in 80% serum resulted in full protection. The protective effect of serum could be replaced by the albumin fraction.
J Cancer Res Clin Oncol 1979 Sep
PMID:Control of in vitro cytotoxicity of positively charged liposomes. 50 Jul 67

77 patients were examined during a period from 1 to 30 days following gastrectomy for cancer. Depression of the exocrine function of the pancreas was observed. The concentration of amylase, lipase and trypsin was found to be reduced during the first 5 days after the operation. Following 19-30 days the amylase concentration is restored, the lipolytic activity is enhanced, whereas the tryptic one remained considerably impaired. The small intestine functioning is markedly disturbed, the processes of hydrolysis and fat absorption suffering most of all; the protein absorption is changed but to a less extent.
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PMID:[Radioisotope and biochemical methods in the study of exocrine function of the pancreas and small intestine at early periods after gastrectomy for cancer]. 50 75

Two pancreatic adenocarcinomas which had been induced in Wistar/Lewis rats by azaserine treatment were transplanted into rats of the same strain by subcutaneous and intraperitoneal injection of minced tumor. Subsequently, we have serially transplanted into non-radiated recipients. Transplanted tumors have maintained evidence of acinar cell differentiation including the presence of zymogen granules in tumors studied by electron microscopy, and of lipase, amylase and trypsin activity in the supernatant of tumor homogenates. Histologically, the tumors vary from poorly differentiated solid carcinomas to well differentiated variants which form acini. Transplanted tumors are locally invasive and have metastasized to lung and liver in some recipients.
Cancer Lett 1979 Aug
PMID:Transplantation of azaserine-induced carcinomas of pancreas in rats. 50 3

The changes in serum trypsin concentration have been measured in 47 subjects for up to 2 hours after a Lundh meal. In 18 healthy controls, mean fasting trypsin concentration was 285 +/- 125 ng/ml (mean +/- 2 SD). The maximum increase after the Lundh meal (the trypsin response ratio) was 6.7 +/- 7.5%. Six patients with chronic renal failure had elevated fasting serum trypsin concentrations (range 460-1100 ng/ml) but trypsin response ratios fell within the control range. Of five patients with relapsing pancreatitis, two had raised and three normal or low fasting trypsins. After stimulation two had elevated trypsin response ratios; one of the two had evidence of main duct obstruction. Eleven out of 12 patients with chronic pancreatitis (with or without insufficiency) had low fasting trypsin concentrations (range 0-120 ng/ml) Seven of the 12 also had raised trypsin response ratios. In six patients with cancer of the pancreas, fasting trypsin was low in three, normal in two, and raised in one. Both patients with a normal fasting level had a raised trypsin response ratio. The combination of a single estimation of fasting serum trypsin concentration followed by serial measurements after a Lundh meal provides a useful screening test for chronic pancreatic disease.
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PMID:Serum immunoreactive trypsin concentration after a Lundh meal. Its value in the diagnosis of pancreatic disease. 52 92

Many strains of mice from various breeding institutes have natural cytotoxic macrophages. These macrophages can also be present in nude mice, suggesting that this cytotoxicity can be acquired without invovlvement of T cells. The natural cytotoxicity was non-specific for tumour cells, was not sensitive to trypsin treatment, was lost after 5 days incubation, but could be enhanced by foetal bovine serum. The presence of cytotoxic macrophages in the peritoneal cavity was not genetically or age controlled. Natural cytotoxic macrophages did not occur in germ-free mice. The possible causes of natural cytotoxicity are discussed.
Br J Cancer 1979 Dec
PMID:Natural cytotoxic macrophages in the peritoneal cavity of mice. 52 27

In poeciliid fish, melanoma of different degrees of malignancy can be produced by crossing specific genotypes. For a detailed investigation of the processes leading to proliferation or differentiation of the melanoma cells, it is necessary to establish cell cultures. The aim of the present study was to find out the optimal conditions for initiating and culturing poeciliid fish cells for the purpose of establishing cell cultures of melanoma. The optimal method was developed by using small pieces of late embryos as starting material and includes: (a) dispersion of tissue by mild stepwise treatment with a trypsin-EDTA mixture at low temperature; (b) culture of cells in the complex medium 199; (c) supplementation of medium with high percentage (20%) of fetal bovine serum; and (d) stabilization of pH by buffering the medium with HEPES. Under these conditions, primary and secondary cultures of embryonic cells have been initiated. An epithelial-like cell line has been subcultured for more than 80 passages. The method developed for embryonic tissues was used to start cell cultures from melanoma of platyfish-swordtail hybrids. Until now, only cells of rapidly growing malignant albino melanoma could be maintained in primary cultures. Secondary cultures could not be initiated since the melanoma cells tended to differentiate and stopped growing before a confluent monolayer was formed.
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PMID:Cell cultures derived from embryos and melanoma of poeciliid fish. 52 10

The effect of ketone bodies on the growth, in culture, of transformed lymphoblasts (Raji cells) was investigated. Cell growth was inhibited and this effect was reversible, non-toxic, and proportional to the concentration of D-beta-hydroxybutyrate up to 20mM. The total glucose utilisation and the total lactate production were reduced in proportion to the inhibition of cell proliferation. D-beta-hydroxybutyrate was not metabolised by the cells. Other glycolytic inhibitors and chemical analogues of D-beta-hydroxybutyrate either did not inhibit or proved to be too toxic for cell growth. D-beta-hydroxybutyrate also inhibited the growth of rabbit kidney (RK13), HeLa, mouse melanoma (B16), fibroblast and trypsin-dispersed human thyroid and beef testis cells. Moreover, in vivo dietary-induced ketosis reduced the number of B16 melanoma deposits in the lungs of C57BL/6 mice by two-thirds. The significance of these results in the clinical management of cancer cachexia is discussed.
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PMID:The inhibition of malignant cell growth by ketone bodies. 54 19

Morphological observations and biochemical analysis were made on glycosaminoglycans produced by MDCK cells of dog kidney origin growing on a glass surface as a mosaic of epithelium with many multicellular hemishperical vesicles. MDCK cells synthesized glycosaminoglycans, which consisted mainly of heparan sulfate and hyaluronic acid. The majority of the substances were contained in a cell-surface component removable with ethylenediaminetetraacetic acid-trypsin. In the radioautograph of tissue sections, high radioactivity of 35SO4 was observed on the medium-bathed cell surface, where Alcian blue-strained material could be observed. Ultrastructurally, the surface of microvillous processes which were abundant on the cell surface in contact with the medium was stained with ruthenium red. A small amount of chondroitin 4- and 6-sulfates were also synthesized. After 24 hr, the majority of chondrotin [35S] sulfates newly formed were secreted into the cultured medium, whereas haparan [35S] sulfate was released much less, remaining as a cellular component. The biological roles of glyconsaminoglycans produced by epithelial cells are discussed.
Cancer Res 1977 May
PMID:Cell surface glycosaminoglycans of cell line MDCK derived from canine kidney. 55 51

The in vitro uptake of phospholipid vesicles by mouse leukemia L1210 cells was examined. Liposomes were generated by prolonged ultrasonic dispersion of aqueous dispersions of mixed lipids in the presence of radiolabeled inulin. Multilamellar vesicles were separated from unilamellar vesicles by column chromatography. Vesicle populations were examined by electron microscopy. Neutral vesicles were generated from egg yolk phosphatidylcholine and cholesterol, and surface charge was introduced via either phosphatidylserine or octadecylamine. Uptake, measured as cell-associated radioactivity, was temperature dependent and was strongly decreased by metabolic inhibitors. These results suggested that liposomes are taken up to a major extent by an energy-dependent mechanism. The uptake of liposomes by cells of a young culture was about 2-fold higher than was the uptake of liposomes by cells of a stationary culture. The uptake of positively charged liposomes by cells was about 20-fold higher than that of either neutral or negatively charged vesicles. About one-half of the cell-associated radioactivity transferred by positively charged liposomes could be removed by cell surface treatment with trypsin or neuraminidase or by a short exposure to 0.6 N NaCl.
Cancer Res 1978 Mar
PMID:In vitro interaction of L1210 cells with phospholipid vesicles. 56 35

Egg lectin of Rana japonica, which specifically agglutinates transformed cells but does not agglutinate nontransformed cells and erythrocytes, has been isolated by gel filtration and successive ion-exchange chromatographies on diethylaminoethyl cellulose and carboxymethylcellulose columns and has been characterized as a homogeneous carbohydrate-free protein with a relative molecular weight of 13,500. The lectin, at a concentration of 1 microgram/0.1 ml, causes obvious cytoagglutination of various transformed and tumor cell. The receptor of the Erlich ascites tumor cells which inhibits the lectin-induced agglutination of the Ehrlich ascites tumor cells has been isolated and characterized. The receptor was solubilized from Ehrlich ascites carcinoma cells by treating a tumor cell suspension with insolubilized trypsin, and the solubilized receptor was isolated by gel filtration through Sephadex G-100, followed by ion-exchange chromatography on diethylaminoethyl cellulose. The receptor was identified as a homogeneous glycoprotein having about 25% carbohydrate. The receptor, at a concentration of 4 microgram/0.1 ml, completely inhibited the cytoagglutination of the Ehrlich carcinoma cells caused by three agglutination doses (about 3 microgram/0.1 ml) of the R. japonica lectin.
Cancer Res 1979 Apr
PMID:Egg lectin of Rana japonica and its receptor glycoprotein of Ehrlich tumor cells. 57 Apr 54


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