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L G Poels

Publications and source records attributed to L G Poels.

At least 55 records · Page 3Linked to original sources
PubMed1987

Time-resolved immunofluorometric assay for the ovarian carcinoma-associated antigenic determinant CA 125 in serum.

A time-resolved immunofluorometric assay (IFMA) is described for quantifying the ovarian carcinoma-associated antigenic determinant CA 125 in human serum. Monoclonal antibody to CA 125 is immobilized onto a microtiter well, and the same antibody labeled with a europium chelate is used as a tracer. After the immunoreaction the bound portion of the labeled antibody is quantified by dissociating the Eu3+ in a fluorescence-enhancement solution and measuring its fluorescence with a time-resolved fluorometer. The detection limit of the IFMA is 1.5 arb. units/mL, being about the same as that of a commercially available immunoradiometric assay (IRMA) for CA 125 (1.4 arb. units/mL). The analytical range of the IFMA extends to 2000 arb. units/mL, whereas the range of the IRMA is 500 arb. units/mL. For 29 serum samples from ovarian-cancer patients measured simultaneously in the IFMA and IRMA, orthogonal regression analysis gave the equation CA 125 (IFMA) = 0.9937 CA 125 (IRMA) - 1.211 arb. units/mL (Syx = 6.8681, r = 0.9932). Apparently, the IFMA for CA 125 is a convenient alternative to the IRMA for CA 125 because of short counting times, the use of nonradioactive, stable reagents, and the much-extended measuring range. Additionally, the microtiter format should lend itself to more fully automated procedures in laboratories doing many such analyses.

Antigens, Neoplasm↗
PubMed1986

Monoclonal antibody against human ovarian tumor-associated antigens.

Mouse monoclonal antibodies (OV-TL 3) were raised against human ovarian tumor-associated antigens for diagnostic purposes. A cloned hybridoma cell line was obtained by fusion of murine myeloma cells with spleen lymphocytes from BALB/c mice immunized with a tumor cell suspension prepared from an ovarian endometrioid carcinoma. The antibodies were initially screened for their ability to bind on frozen sections of human ovarian carcinoma tissue and a negative reaction on gastric carcinoma tissue by indirect immunofluorescence. The reactivity of the selected OV-TL 3 clone (IgG1 subclass) was studied on normal and neoplastic tissues as well as on a cell line derived from the original tumor cell suspension used for immunization. OV-TL 3 antibodies stained frozen sections of human ovarian carcinomas of the following histological types: serous, mucinous, endometrioid, and clear cell. No reaction was found with breast cancers or other nongynecological tumors. No differences in staining pattern were observed between primary and metastatic ovarian carcinomas. OV-TL 3 antibodies brightly stained ovarian carcinoma cell clusters in ascitic fluids and left unstained mesothelial cells and peripheral blood cells. The OV-TL 3-defined antigen also remained strongly expressed on a cell line derived from the endometrioid ovarian carcinoma originally used for generation of OV-TL 3 clone. Reactivity was weak and irregular in a few ovarian cysts, while traces of fluorescence were sometimes detected in epithelial cells lining the female genital tract. In only 3 specimens of 15 endometrium carcinomas was weak focal reactivity with OV-TL 3 antibodies observed. The results of the immunofluorescence study were confirmed by the more sensitive avidin-biotin method and by 125I-labeled OV-TL 3 antibodies. Thus OV-TL 3 recognizes a common antigen for most ovarian carcinomas and may be a useful tool for rapid diagnosis of ovarian carcinomas.

Animals↗
PubMed1983

Plasmodium berghei: influence on granulopoiesis and macrophage production in BALB/c mice.

Granulocyte and macrophage progenitor cells forming colonies in vitro (GM-CFC) from bone marrow, spleen, and peripheral blood of BALB/c mice infected with Plasmodium berghei were cultured at various times postinfection in a viscous, 0.8% methylcellulose system. The numbers of GM-CFCs from bone marrow increased gradually during the first week of infection, reaching a maximum around the tenth day of the disease. Subsequently, a rise of GM-CFCs in cultures of nucleated cells from the peripheral blood was observed and, with some delay, in spleen cell cultures also, with a maximum around the end of the second week. After the tenth day of malaria infection a fall of colony frequency in bone marrow-derived cells took place, leading to subnormal values of GM-CFCs during the third week of infection. Subsequently, a decrease in the spleen cell cultures followed, but colony numbers did not fall to normal values. The general increase in GM-CFCs in the different organs was preceded by a rise in serum levels of colony-stimulating activity (CSA), attaining a maximum 1 week after P. berghei inoculation. During the following period the CSA levels fell and reached normal values around the seventeenth day of the disease. Chemotherapy with chloroquine started on the fifteenth day of infection, when GM-CFCs in the bone marrow have dropped to normal values, stopped their further decrease. In the spleen a gradual normalization took more than 2 weeks. A challenge infection evoked an elevation of GM-CFC numbers in the bone marrow and in the spleen during the first 10 days in only about 50% of immune mice. The reaction was immediate in some animals, but generally lower and of shorter duration than during primary infection. The results have indicated that a lethal P. berghei infection in mice caused a transient increase in production of CSA followed by a general recruitment of GM-CFCs in all hemopoietic organs.

Animals↗
PubMed1983

Parietal cell antibodies in relation to basal serum gastrin in a normal population.

Parietal cell antibodies, basal gastric pH and serum gastrin were determined in 544 normal non-achlorhydric subjects. Serum gastrin was significantly higher in subjects with parietal cell antibodies, both in the group with a weakly positive and in that with a strongly positive fluorescence score. The elevated serum gastrin level in subjects with circulating parietal cell antibodies was independent of gastric pH. It is suggested that parietal cell antibodies may interfere with gastrin receptors on the membrane of the parietal cell, thus influencing the feedback mechanism between the secretion of acid and gastrin, and resulting in an increase of the basal serum gastrin level at an unchanged basal gastric pH.

Adult↗
PubMed1980

Is actin in eye lens a possible factor in visual accomodation?

Actin has been purified from varius non-muscle cells and characterized by its molecular weight and ability to polymerize into filaments. Although the occurrence of this protein has been postulated in the mammalian eye lens after observation of actin-like filaments in the electron microscope, definite (bio)chemical proof has been provided only recently. Amino acid analysis, peptide mapping and affinity chromatography revealed the identity of lens actin with the corresponding protein in other tissues. As the filaments could be obtained by co-isolation with highly purified lens plasma membranes, we were interested to know how the actin-containing structures wre located in situ. In the experimental approach reported here, the indirect immunofluorescence technique (IFT) was applied to unfixed cryostat sections of lens tissue. The distribution of actin in calf, rat and pigeon lens is described, and evidence from this for the role of actin in visual accommodation discussed.

Accommodation, Ocular↗
PubMed1978

Clomerulopathy in mice infected with Plasmodium berghei: induction of an autoimmune process.

1. Apparently a living, metabolizing parasite is required to induce the formation of autoantibodies. 2. It seems unlikely that immune complexes of the first type, i.e., positive for plasmodial antigens, are responsible for the induction of autoantibodies, as the transferred malarious plasma (group B) also contained that type of immune complex, but did not induce the formation of the second type of complex. 3. Although a deregulation of the immunocompetent system will occur in animals with a high parasitemia (immunosuppression), the fact that extremely low parasitemia is sufficient to induce antismoothmuscle antibodies suggests that proliferation of "forbidden clones" of self-reactive lymphocytes is not very likely. 4. Antismooth-muscle antibodies are frequently associated with active chronic hepatitis in man. Whether any damage to liver tissue (6) during malaria infection may be responsible for the induction of antismoothmuscle antibodies remains to be investigated. The clinical relevance of these findings is as yet obscure, and one should be careful in comparing these results of the rodent model with the human situation. 5. It remains to be elucidated whether the high level of so-called nonspecific antibodies in acutely infected mice can be explained entirely by the existence of antibodies to parasitic antigens and to host smooth-muscle antigens.

Animals↗
PubMed1976

Polyribosome profiles and ribonuclease activity in spleens of normal and anaemic mice.

The extent to which the polyribosome content in splenic extracts is affected by the level of endogenous ribonuclease activity was investigated. Ribonuclease activity, free and inhibited, was determined under ionic conditions optimal for preservation of polyribosomes. The results show that ribonuclease activity in control spleens varies mainly with the amount of ribonuclease inhibitor, indicating that free ribonuclease activity is stable. In rapidly proliferating splenic tissue the enzymatic activity is regulated by changes in both the amount of inhibitor and enzyme available. The ribonuclease versus ribonuclease-inhibitor balance was found to parallel the proportion of polyribosomes in a polysome profile.

Anemia↗