Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By observing increases in the transepithelial paracellular permeability of a range of radiolabeled solutes and electron dense dyes, changes in molecular sieving caused by the cytokine, TNF (tumor necrosis factor), and the phorbol ester, TPA (12-0-tetra-decanoylphorbol-13-acetate), were characterized. Using 14C-labeled mannitol (mw 182), raffinose (mw 504), PEG (polyethylene glycol; mw 4000), and dextran (mw 10,000, 70,000 and 2,000,000), the transepithelial flux rates of these compounds were determined at the peak of the transepithelial electrical resistance (TER) changes caused by these two agents. TNF treatment resulted in increased permeability across LLC-PK1 epithelial cell sheets only to relatively small solutes, with an upper limit of approximately 4,000 mw. The low molecular weight "ceiling" for the TNF-treated epithelium is further evidence against TNF increasing transepithelial permeability by means of inducing nonspecific, microscopic "holes" in the epithelium, for which a "ceiling" would not exist. TPA treatment increases transepithelial paracellular permeability to a much broader range of solutes, extending well beyond 2 million mw. Transmission electron micrographs provide evidence that even the electron-dense dye complex, ruthenium red, can cross tight junctions of TPA-treated cell sheets. However, cationic ferritin cannot cross tight junctions of TPA-treated cell sheets. This shows that there is an upper limit to solutes able to cross TPA-treated cell sheets, but that this upper limit will include most proteins, which would then be able to cross tumor promoter-exposed (protein kinase C-activated) epithelial layers at accelerated rates. The biomedical implications for a high molecular weight cutoff in tumor promoter action in epithelial carcinogenesis, and for a low molecular weight cutoff in cytokine-induced epithelial apoptosis in inflammation, are discussed.
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PMID:Different size limitations for increased transepithelial paracellular solute flux across phorbol ester and tumor necrosis factor-treated epithelial cell sheets. 913 Apr 71

Methoxypoly(ethylene glycol) (PEG) modification of Escherichia coli beta-glucuronidase (betaG) was examined as a method to improve the stability and pharmacokinetics of antibody-betaG conjugates for the targeted activation of glucuronide prodrugs at tumor cells. Introduction of 3 PEG molecules did not affect betaG activity whereas higher degrees of PEG modification produced progressively greater loss of enzymatic activity. The enzyme was found to be stable in serum regardless of PEG modification. PEG-modified betaG was coupled via a thioether bond to mAb RH1, an IgG2a antibody that binds to the surface of AS-30D hepatoma cells, to produce conjugates with 3 (RH1-betaG-3PEG), 5.2 (RH1-betaG-5PEG) or 9.8 (RH1-betaG-10PEG) PEG molecules per betaG with retention of 75%, 45% and 40% of the combined antigen-binding and enzymatic activity of the unmodified conjugate RH1-betaG. In contrast to the rapid serum clearance of RH1-betaG observed in mice, the PEG-modified conjugates displayed extended serum half-lives. RH1-betaG-3PEG and RH1-betaG-5PEG also exhibited reduced spleen uptake and greater tumor accumulation than RH1-betaG. BHAMG, the glucuronide prodrug of p-hydroxyaniline mustard (pHAM), was relatively nontoxic in vivo. Injection of 6 mg/kg or 12 mg/kg pHAM i.v. depressed white blood cell numbers by 46% and 71% whereas 80 mg/kg BHAMG reduced these levels by 22%. Although the tumor/blood ratio of RH1-betaG-5PEG was adversely affected by slow clearance from serum, combined therapy of small solid hepatoma tumors with this conjugate, followed 4 and 5 days later with i.v. injections of BHAMG, cured all of seven mice with severe combined immunodeficiency. Combined treatment with a control antibody-betaG conjugate and BHAMG delayed tumor growth and cured two of six mice while treatment with pHAM or BHAMG alone was ineffective.
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PMID:Poly(ethylene glycol) modification of beta-glucuronidase-antibody conjugates for solid-tumor therapy by targeted activation of glucuronide prodrugs. 929 32

Polyethylene glycol (PEG-8000) -modified recombinant human interleukin-2 (PEG-rIL-2) is a cytokine with prolonged circulatory half-life. In this paper, the antitumor effects of PEG-rIL-2 against mouse uterine cervical carcinoma (U14) transplanted intraperitoneally or subcutaneously is reported. PEG-rIL-2 at different doses was administered intratumorally. The results showed that PEG-rIL-2 (4,500 IU, i.p., QD x 5) prolonged survival time of mice bearing ascites tumor as compared to rIL-2 (P < 0.01), but PEG-rIL-2 at lower doses was without therapeutic effect. In addition, compared to rIL-2, PEG-rIL-2 at different doses (1,500-13,500 IU, QD x 5) caused significant dose-dependent growth inhibition of solid tumor (P < 0.01) when the treatment started on lay 4 after subcutaneous inoculation of tumor.
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PMID:[In vivo antitumor effects of polyethylene glycol--modified recombinant human interleukin-2 on mouse uterine cervical carcinoma]. 938 13

Efficacy and safety data of liposomal drugs in a laboratory environment are often not reproduced on an industrial production scale. This is largely due to the fact that the colloid-chemical properties of the liposomes manufactured on a small scale are not reproduced in large scale production. Though the size and the electric charge of liposomes are measured and are adequately specified in relation to the bio-distributions in most developments of liposomes (1), uniformity of lipid components, exposure of bio-chemically important functional groups on the outer surface of liposomes (2), fixed aqueous layer thickness (FALT), number of the lipid bilayers, etc., are dependent upon the scale of production. Nevertheless these properties are not always exactly specified. Uniformity, especially of the functional groups on the membrane surface can be assessed chemically or bio-chemically with fractionated samples, and FALT can be easily determined through electro-chemical means (3). In this review, colloid chemical characterization of liposomes is introduced, FALT as an example, and its importance in a quality control of a liposomal product in an industrial scale production is shown. Methoxy-polyethyleneglycol-diacylglycerol (PEG-DAG) with varying PEG chain length and acyl chains were synthesized, FALT of liposomes coated with PEG-DAG determined and tissue distribution in tumor bearing mice. The higher incorporation ratio of PEG-DAG into liposomal membrane was observed with PEG-DAG with short acyl chains (myristoyl) and a small PEG molecular weight (1000). The easier to incorporate, the easier to be stripped in the serum. The disposition data in the rats well reflected the colloid chemical and in vitro data of the PEG liposomes. Galactosyl-carbonyl-propionyl-polyethyleneglycol-diacylglycerol (Gal-PEG-DAG) with oxyethylene number, n = 10, 20 and 40 were synthesized. The exposure of the galactose residue beyond the fixed aqueous layer of liposomes coated with Gal-PEG-DAG was monitored by a lectin, Ricinus communis agglutinin (RCA) induced agglutination, the half life in the blood after i.v. injection into rats, organ distribution determined and intrahepatic distribution studied. Only the liposomes containing the Gal-PEG10-DAG aggregated with the lectin, indicating that only with this derivative the galactose group was adequately exposed. The Gal-PEG10-DAG liposomes were cleared from the plasma with a half life of 0.3 h. The plasma elimination could be attributed entirely to increased uptake by the liver. The increased liver uptake was almost entirely attributed to increased uptake by the non-parenchymal cell. Incorporation of PEG-DSPE in to the Gal-PEG10-DAG liposomes caused 1) a three-fold increase in blood circulation time, 2) a small but significant decrease in hepatic uptake after 20 h and 3) a significant shift in intrahepatic distribution in favor of the hepatocytes, comparable to that of the control liposomes. In conclusion, therapeutic efficacy and safety of liposomes can be controlled by their colloid chemical, more exactly, surface chemical properties. By setting up reasonable quality control specification of the properties in laboratory and examining the specifications satisfied in upscaling, the efficacy and safety are reproduced in a large scale product.
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PMID:[An importance of colloid chemical characterization of liposomes for DDS in a large scale production]. 943 6

Circulating immune complexes (CIC) were estimated in 48 Patients of genitourinary cancer by polyethylene glycol precipitation (PEG pptn.) test and latex agglutination inhibition (LAI). The results were compared with 25 healthy control volunteers. Pathological levels of CIC were observed in 79.18 percent patients of genitourinary cancer by combination of PEG pptn. and LAI tests, while no seropositivity for CIC was observed in control group (p < 0.001). Sequential increase in seropositivity for CIC was observed with advancing stage of genitourinary cancer i.e. number of seropositive patients in cancer stage I were 60 percent, stage II-71.42 percent, stage III-85.71 percent and stage IV-100 percent. Variation IN CIC levels in different patients within the same stage are compared. Circulating antigen antibody complexes have a significant role as prognostic monitors in management of genitourinary cancer patients. Statistical evaluation of data on intra- and inter-assay variation has been given. CIC levels rise with increases in tumor burden in vivo hence variation in CIC levels within the same stage in different patient have a significant role as prognostic monitors in management of individual patients.
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PMID:Role of circulating immune complexes in prognostic evaluation and management of genitourinary cancer patients. 949 72

Cell-mediated immunity (CMI) and circulating immune complexes (CIC) were estimated in 55 cancer patients and 25 control volunteers to evaluate their prognostic significance. Cancer patients comprised head and neck cancer (11), breast cancer (13), gastrointestinal cancer (10), genitourinary cancer (11), and lymphomas and sarcomas (10). CMI was tested in vitro by early rosette-forming cells (ARFC) and total rosette-forming cell (TRFC) counts. ARFC count in control group was 758.1 +/- 78.09 cells/cumm. In advancing clinical stages of cancer (I-IV), ARFC counts were decreased (i.e., 601.12 +/- 74.96 [p < 0.01]; 494.8 +/- 71.83 [p < 0.001]; 432.44 +/- 36.05 [p < 0.001], and 438.55 +/- 69.99 [p < 0.001] cells/cumm, respectively). TRFC count in control group was 1029 +/- 88.39 cells/cumm. In cancer stages I through IV, these counts decreased significantly (i.e., 699.63 +/- 66.24; 597.55 +/- 82.9; 505.11 +/- 52.56; and 501.55 +/- 69.99 cells/cumm, respectively [p < 0.001]. Dinitrochlorobenzene cutaneous reactivity in vivo was 100% positive in control group, 62.5% positive in cancer stage I, 5% positive in stage II, and negative in stages III and IV. CIC of intermediate size were estimated by polyethylene glycol precipitation (PEG pptn) technique, which detects CIC in the ratio of 2:1 (Ag2Ab). Mean PEG index in control group was 39.5 +/- 4.65; sequential increase in CIC was observed in advancing clinical stages of cancer (I-IV)(i.e., 49 +/- 7.03 [p < 0.01]; 75.38 +/- 44.01 [p < 0.001]; 93.38 +/- 44.57 [p < 0.001]; and 216.00 +/- 147.05 [p < 0.001], respectively). Latex agglutination inhibition (LAI) titer was done to detect CIC as small as 8s, which constitute the opposite polar end of CIC spectrum. LAI titers in control group were nil. However, LAI titers in cancer stages I through IV were 1 +/- 2.64; 8.6 +/- 5.6 (p < 0.001); 12.00 +/- 8.11 (p < 0.001); and 25.77 +/- 9.06 (p < 0.001), respectively. Decrease in CMI and subsequent increase in CIC indicate unfavorable prognosis in cancer patients, and also precede clinical manifestation of increased tumor mass in vivo.
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PMID:Evaluation of cell-mediated immunity and circulating immune complexes as prognostic indicators in cancer patients. 954 29

The current status of newly developed polyethyleneglycol coated liposome (PEG-liposome) were described in this review. Liposomes have demonstrated considerable promise as a carrier for the delivery of drugs in vivo. However, one of the drawback is that most liposomes intravenously injected into animals are rapidly removed from the blood circulation by uptake primarily in the cells of reticuloendothelial system (RES). It has been found that PEG-liposome are not readily taken up by the macrophages in the RES and hence stay in the circulation for a relatively long period of time. Pharmacokinetic analysis and therapeutic studies with tumor bearing mice revealed that PEG-liposomes have considerable potential as drug carriers for cancer therapy. Elevated liposome accumulation has been found in the tumor bearing mice model system. Results from clinical studies with doxorubicin encapsulated into PEG-liposomes (DOXIL) in AIDS-related Kaposi's sarcoma revealed an increased therapeutic efficacy compared to free-drug. These new formulations of long-circulating liposomes (PEG-liposome) offer the development of immunoliposomes with both long survival times in circulation and target recognition being retained in vivo. Fab'-PEG-immunoliposome was newly designed to gain long-circulating enough to extravasate to the targeted solid tumor in vivo. An ultimate goal of Fab'-PEG-immunoliposome is the incorporation of a fusogenic molecules that would induce fusion of liposome following their binding to the target cells or their internalization by endocytosis. Such liposomal formulations should be useful for endocytotic internalization of plasmid DNA and other bioactive materials.
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PMID:[PEG-liposome in DDS and clinical studies]. 954 48

For the purpose of intracellular targeting carrier by systemic administration, PEG-liposomes conjugating transferrin (TF) at the distal ends of PEG chain were newly prepared. Biodistribution of TF-PEG liposome was examined in the colon 26 bearing mice. TF-PEG liposome were prolonged in the circulation and highly accumulated into the tumor tissue. After extravasation, TF-PEG liposome retains the specific binding ability to tumor cell surface. Uptake of TF-PEG liposome was examined by electron microscopy. TF-PEG liposome was localized at the cell surface, coated pits and endosome. These results show TF-PEG liposome was bound and internalized by endocytosis. Such liposomes should be useful for intracellular targeting carrier at the way of systemic administration.
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PMID:[Transferrin conjugated PEG-liposomes as intracellular targeting carrier for tumor therapy]. 954 52

MFE-280 endometrial cancer cells express PP14 (placental protein 14) in vitro. PP14 is normally found in the secretory endometrium and in placental tissue. MFE-280 cells, which are tumorigenic in nude mice, were derived from a recurrent, poorly differentiated endometrial carcinoma. The cells were initially grown in suspension culture and later transferred to monolayer cultures. Karyotyping revealed near-diploidy with a complex heterogeneous aberration pattern. MFE-280 cells were positive for the cytokeratins 7, 8, 18 and 19 as well as for vimentin. The expression of PP14 in MFE-280 cells was demonstrated by immunochemistry and reverse transcriptase--polymerase chain reaction. PP14-mRNA was also detected in one out of five endometrial cancer specimen. In tumor tissue the expression of PP14 was not dependent on progestins.
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PMID:Expression of placental protein 14 by the new endometrial cancer cell line MFE-280 in vitro and by endometrial carcinomas in vivo. 961 81

By means of a simplified questionnaire, the NADYA group has gathered and analyzed data with regard to the age, sex, diagnosis, access route, duration, form of administration, complications, and quality of life, in 812 patients (62% male; 37% female) with At Home Enteral Nutrition (AHEN), and 19 patients (42% male; 57% female) with At Home Parenteral Nutrition (AHPN) corresponding the National Registry of 1995. The most frequent indication of AHEN was a neoplasm (41%), followed by neurological alterations (33%). The most common access route is the NGT (37%) followed by oral administration in 37%, PEG in 13% and surgical ostomics in 8%. The mean treatment time is 8 months. The index of complications/patient-year is 0.50 (gasterointestinal 0.17, and mechanical alterations 0.9). At the end of the study, 63% of the patients continued to receive AHEN, showing a mortality rate of 70%. The majority of the patients undergoing treatment presented a sever social disability (20%) or were bed ridden (18%). The most common indications for the AHPN are: radical enteritis (26%), Crohn's disease (21%), and mesenteric ischemia (16%). AIDS, motility alterations, and neoplasic diseases are scantly represented (10%). Tunneled catheters are used in 58% of the cases, and Port-a-Cath in 31%). The mean duration for the treatment was 7.9 months. An index of 0.47 hospitalization/patient-year was seen in relation to the nutritional treatment (mainly due to catheter septicemia). A mortality of 16% is noted, and 21% show a recovery of the oral route. 42% of the patients did not present an assessable social disability.
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PMID:[Artificial nutrition in the home. 1995 yearly report. NADYA-SENPE Group (Natiional Registry of Patient-Spanish Society for Parnteral and Enterlal Nutrition]. 966 56


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