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Biomedical subjects

A Hedin

Publications and source records attributed to A Hedin.

At least 55 records · Page 3Linked to original sources
PubMed1982

Exclusive occurrence of thermogenin antigen in brown adipose tissue.

Thermogenin is the purine-nucleotide binding polypeptide in brown adipose tissue mitochondria (Mr 32 000) which confers upon these mitochondria the ability to produce heat. An enzyme-linked immunosorbent assay (ELISA) has been developed to demonstrate and quantitate the occurrence of thermogenin antigen in small amounts of tissue, and thus to characterize different depots of fat tissue as white or brown. The extreme sensitivity of the method allows determination of thermogenin in samples equivalent to less than 1 mg tissue. The results indicate that thermogenin seems to be exclusively localised in brown fat mitochondria (as compared to white fat, liver or heart muscle mitochondria), and thermogenin antigen could only be found in brown adipocytes (as compared to white adipocytes). Thus, brown and white adipose tissue are probably ontogenetically different.

Adipose Tissue↗
PubMed1982

Tumor localization of CEA-containing human tumors in nude mice by means of monoclonal anti-CEA antibodies.

Three different monoclonal antibodies (mabs) directed against conformation-dependent protein determinants in carcinoembryonic antigen (CEA) were evaluated for tumorimmunolocalization of CEA-containing human tumors grown in nude mice. The antibodies were of high affinity and of the IgG1 subclass. They did not react with non-specific cross-reacting antigen (NCA), biliary glycoprotein I (BGP I) or orosomucoid. 10-20 muCi (1-2 micrograms) of 131I-labelled mab was injected intraperitoneally into mice bearing heterografts of the CEA-containing human tumor cell lines LS 174T, Detroit 562 or HT-29 or into mice bearing grafts of the non-CEA-containing human tumor cell line RD. The concentration of radiolabelled mab in the tumor compared with the mean concentration in the mouse increased up to day 4 after injection. In contrast, the concentration ratios of radioactivity in the other tissues decreased with time. Excellent tumor localization was obtained with mab 38S1 in mice bearing LS 174T tumors. The concentration of radioactivity (cpm/g) tissue wet weight) was 24-390 times higher in the tumor than in the muscle. The difference between tumor and liver and between tumor and blood was 4-89 times and 2-25 times, respectively. A mean value of 40% of the total radioactivity in the mouse at day 4 was localized to the tumor. Mab 38S1 also showed positive tumor localization in mice carrying Detroit and HT-29 tumors. Means of 22% and 18% of the total radioactivity in the mouse at day 4 were found in these tumors, respectively. Mab 38S1 was, however, not enriched in the tumor of mice bearing the non-CEA-containing sarcoma RD. Furthermore, when LS 174T tumor-bearing mice were injected with normal mouse IgG, no enrichment of radioactivity in the tumor was seen. Positive tumor localization with mab 48 was obtained while mab 9 was not enriched in the tumor. Scanning pictures of LS 174T-grafted mice on day 4 after injection of 131I-mab 38S1 showed a definite radioactive spot corresponding to the tumor and in addition a spot corresponding to the liver or the heart.

Animals↗
PubMed1982

Specificities and binding properties of eight monoclonal antibodies against carcinoembryonic antigen.

Eight different monoclonal antibodies against CEA were derived from fusions with spleen cells of mice immunized with highly purified CEA. All eight antibodies were IgG l, kappa and had isoelectric points between pH 6.5 and 7.5. They reacted strongly with native CEA, Smith degraded CEA (SI-stage) and CEAlow, only marginally with reduced and alkylated CEA and not at all with orosomucoid, indicating that they were directed against conformation dependent protein determinants. Two antibodies cross-reacted strongly with nonspecific cross-reacting antigen (NCA) while none of the antibodies cross-reacted with biliary glycoprotein I (BGP I). At least six different epitopes in the peptide moiety of CEA were recognized by this series of monoclonal antibodies. At least two of these appeared to occur twice in the molecule, possibly indicating that CEA contains two or more homology regions. The affinity constants of three of the CEA-'specific' antibodies were found to be very high, e.g. 1.2, 3.3, and 7.4 X 10(8) M-1, respectively.

Animals↗