To characterize antigenic sites in carcinoembryonic antigen (CEA) further and to investigate whether there are differences between colon tumor CEA and meconium CEA (NCA-2) that can be detected by anti-CEA monoclonal antibodies (MAb), 19 new anti-CEA MAb were analyzed with respect to specificity, epitope reactivity and affinity. Their reactivities were compared with 10 anti-CEA MAb with known CEA-domain binding specificity that have previously been classified into five nonoverlapping epitope groups, GOLD 1-5. Cross-inhibition assays with antigen-coated microtiter plates and immunoradiometric assays were performed in almost all combinations of MAbs, using conventionally purified CEA (domain structure: N-A1B1-A2B2-A3B3-C) from liver metastasis of colorectal carcinomas, recombinant CEA, meconium CEA (NCA-2), truncated forms of CEA and NCA (CEACAM6) as the antigens. The affinity of the MAbs for CEA was also determined. The new MAbs were generally of high affinity and suitable for immunoassays. Three new MAbs were assigned to GOLD epitope group 5 (N-domain binding), 3 MAbs to group 4 (A1B1 domain), 1 to group 3 (A3B3 domain), 3 to group 2 (A2B2 domain) and 3 to group 1 (also the A3B3 domain). Three MAbs formed a separate group related to group 4, they were classified as GOLD 4' (A1B1 domain binding). The remaining 3 MAbs appear to represent new subspecificities with some relationship to GOLD groups 1, 2 or 4, respectively. Five MAbs, all belonging to epitope group 1 and 3, reacted strongly with tumor CEA but only weakly or not at all with meconium CEA, demonstrating that the two products of the CEA gene differ from each other, probably due to different posttranslational modifications.

Animals↗

PubMedDate not supplied

Prognostic value of carcinoma-associated antigen MK-1 in urinary bladder carcinoma.

BACKGROUND: The present study has been performed to evaluate the expression of MK-1 in schistosomiasis-associated squamous cell carcinoma of the urinary bladder and to correlate this new marker with the conventional histopathological parameters. PATIENTS AND METHODS: Paraffin sections of 5-microm thickness from 81 cases were prepared for hematoxylin and eosin staining and immunohistochemical analysis of MK-1 expression was carried out. RESULTS: Forty-six cases (56.8%) were positive for MK-1 protein expression. Significant correlations between MK-1 expression and tumor grade (p=0.004), schistosoma (p=0.031), DNA ploidy (p=0.001), and tumor recurrence (p<0.001) were observed. MK-1, sex, tumor grade, stage, schistosoma, DNA ploidy, and recurrence were evaluated in relation to outcome. Univariate and multivariate analysis of survival were performed. The overall 5-year survival was 51.85%. In univariate analysis, MK-1 expression, tumor grade, DNA ploidy, and recurrence had a significant impact on the survival of these patients. In a Cox proportional hazards model, recurrence maintained its significant impact on survival. CONCLUSIONS: These findings suggest that MK-1 is a prognostic marker for recurrence: 34 (87.2%) of 39 recurrent cases were positive for MK-1 expression. However, only recurrence was an independent prognostic factor in patients with schistosomiasis- associated squamous cell carcinoma of the bladder.

Adult↗

PubMedDate not supplied

Reactivities of an anti-CEA peptide monoclonal antibody.

Synthetic peptides representing different areas of the CEA molecule were used as immunogens for the development of anti-CEA antibodies. Both polyclonal and monoclonal antibodies were generated using peptides composed of CEA amino acid positions 99-128 and 585-613, respectively. One MAb, designated CP4, generated using the CEA peptide 99-128, was chosen for a more detailed analysis of reactivity. MAb CP4 reacts in solid phase RIAs with CEA peptide 99-128 immunogen and purified native CEA. CP4 did not react with purified non-specific cross reacting antigen (NCA), even though there were two single amino acid differences between NCA and CEA in the 29 amino acid peptide. The affinity constants of CP4 for the CEA peptide 99-128 and native CEA are 4.07 x 10(9) M-1 and 5.75 x 10(8) M-1, respectively. When CP4 was reacted with purified CEA in Western blotting experiments, the Mr 180,000 glycoprotein characteristic of CEA was detected, but CP4 reacted to various size entities in tumor cell extracts. The results of liquid competition RIAs showed that the epitope that MAb CP4 recognized on native CEA is not available for binding when CEA is in solution. Physical (adsorption to a solid matrix) or chemical (deglycosylation or formalin-fixation) alteration of CEA is required for binding of CP4 to CEA. MAb CP4 reacted approximately 1,000-fold greater to deglycosylated CEA than native CEA. Immunohistochemical studies using formalin-fixed paraffin-embedded tissue sections demonstrated that, among carcinomas, CP4 reacts selectively with colorectal carcinomas, while normal colon is negative. Although stomach carcinoma is negative, dysplastic lesions and areas of intestinal metaplasia are reactive. Two of 7 normal stomach tissues showed focal cytoplasmic reactivity of the surface epithelium. CP4, therefore, appears to react with an epitope with highly restricted expression in colorectal carcinoma. These studies demonstrate the complexities in dealing with an anti-peptide MAb with reactivity to an epitope which is accessible only under certain conditions.

Amino Acid Sequence↗

PubMedDate not supplied

Middle-latency responses of awake and anesthetized Japanese macaques.

The middle-latency response (MLR) of two Japanese macaques were investigated. In the awake state, the configuration of the MLR components showed two positive peaks: Pa and Pb. The latency and the configuration of Pa were very similar to those of humans. In the topographic recordings, the largest Pa amplitude was found from the vertex, or R1, which is 1 cm lateral to the vertex. In the anesthetic state, Pa and Pb gradually disappeared. This study shows that the MLR in awake Japanese macaques is similar to that in humans, and differs from that in cats. Therefore these awake monkeys are suitable as animal models of human MLR.

Acoustic Stimulation↗

PubMedDate not supplied

Antitumour effect of interferon combined with hyperthermia against experimental brain tumour.

Antiproliferative activity of recombinant murine interferon-beta (Rec-MuIFN-beta) combined with hyperthermia against Rous sarcoma virus-induced mouse malignant glioma (RSV glioma) was investigated both in vitro and in vivo. In vitro, the antiproliferative activity of Rec-MuIFN-beta was enhanced by incubation at elevated temperatures (40 degrees and 43 degrees C). In vivo, combined therapy of Rec-MuIFN-beta treatment and local tumour hyperthermia (43 degrees C) exerted a greater antitumour effect against transplanted RSV glioma in C3H/He mice than either treatment alone, especially when Rec-MuIFN-beta was administered intratumourally. Subsequently, in order to probe the mechanism of enhanced antiproliferative activity, the production of prostaglandin E2 (PGE2) and 2', 5'-oligoadenylate synthetase (2-5A synthetase) in the culture medium of RSV glioma cells was measured. Rec-MuIFN-beta treatment resulted in a significantly greater PGE2 and 2-5A synthetase production at 43 degrees C than at 37 degrees C.

2',5'-Oligoadenylate Synthetase↗

PubMedDate not supplied

Effects of antineoplastic agents and hyperthermia on cytotoxicity toward chronically hypoxic glioma cells.

The effects of hyperthermia and antineoplastic agents on the cytotoxicity to normally oxygenated and chronically hypoxic glioma cells were investigated in vitro. Exposure to temperatures above 43.0 degrees C was less cytotoxic to hypoxic cells which predominantly accumulated in the G0/G1 phase fraction. On the other hand, mitomycin C (MMC) and adriamycin (ADM) were preferentially cytotoxic to hypoxic cells not only at 37 degrees C but also at elevated temperatures (42 degrees C and 43 degrees C). These two agents showed marked synergistic effects with hyperthermia under both oxygenated and hypoxic conditions. In contrast, bleomycin (BLM), cis-diamminedichloroplatinum(II) (CDDP), and vincristine (VCR) were preferentially cytotoxic to oxygenated cells at both 37 degrees C and elevated temperatures. CDDP showed cytotoxic synergism with hyperthermia that appeared to be oxygen-dependent. A nitrosourea derivative, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), showed no major preferential toxicity under either oxygenated or hypoxic conditions. This study suggests that hyperthermia in combination with MMC or ADM would have a greater cytotoxic effect on hypoxic cell subpopulations of malignant gliomas.

Antineoplastic Agents↗

PubMedDate not supplied

Drug delivery to the brain using thermosensitive liposome and local hyperthermia.

We investigated the possibilities of drug delivery to the brain using thermosensitive liposomes and hyperthermia. Thermosensitive liposomes are small vesicles containing some drugs, which are designed to release the drugs in response to hyperthermia. The first experiment consisted of four groups: (1) received free Cisplatin: cis-diamminedichloroplatinum (CDDP); (2) received free CDDP and above 41 degrees C local brain heating for 30 min; (3) received liposomes containing CDDP (CDDP-liposome); and (4) received CDDP-liposome and above 41 degrees C local brain heating for 30 min. Brain CDDP levels were significantly higher in (4), while those on the other groups were undetectable. In the second experiment, we studied the distribution of Evans blue (Eb) in the artificially heated region of mongrel dogs' brain. One group received free Eb and the other group received liposomes containing Eb (Eb-liposome). While the extravasation of free Eb was localized in regions heated > 44 degrees C, that of Eb-liposome was extended up to the regions heated at 41 degrees C. We concluded that the use of thermosensitive liposomes and hyperthermia not only contributes to the brain tumour killing as direct thermal killing does but also helps to increase the concentration of chemotherapeutic drugs into the tumour invaded zones with mild local hyperthermia of 41 degrees C.

Animals↗

PubMedDate not supplied

Binding reactivity of monoclonal anti-carcinoembryonic antigen (CEA) antibodies with cell membrane-bound CEA and with free CEA in solution.

Binding reactivities of 62 anti-CEA MAbs from 10 different research groups with cell membrane-bound CEA and with free CEA in solution were compared by inhibition of MAb binding to CEA-expressing tumor cells by free CEA. Bindings of 30 MAbs to the cell membrane-bound CEA (280 ng CEA/2 x 10(5) cells) were inhibited by approximately equal amounts of free CEA, indicating that binding affinities of about half the MAbs for cell membrane-bound CEA are similar to those for free CEA, respectively. Bindings of 15 MAbs to the cell membrane-bound CEA were easily inhibited by free CEA of less than half the amount of the cell membrane-bound CEA, while inhibition of bindings of the remaining 17 MAbs required twice more free CEA than the amount of cell membrane-bound CEA, showing that about one-fourth of the MAbs have higher affinities for free CEA and the remaining about one-fourth of the MAbs possess higher affinities for cell membrane-bound CEA. These results help form the basis for selecting the anti-CEA MAbs for use in clinical applications, such as serum CEA assay, tumor imaging and immunotherapy.

Adenocarcinoma↗

PubMedDate not supplied

Nonspecific cross-reacting antigen-50/90 (NCA-50/90) as a new tumor marker.

BACKGROUND: The nonspecific cross-reacting antigen-50/90 (NCA-50/90) is a glycoprotein antigen which shares some antigenic determinants with carcinoembryonic antigen (CEA). No definite clinical value has been established for the measurement of NCA-50/90 in cancer patients. METHODS: We established and evaluated a chemiluminescent enzyme immunoassay (CLEIA) specific for NCA-50/90 using two monoclonal antibodies. RESULTS: No significant reactivity with 4 purified related antigens including CEA was found in the NCA-50/90 CLEIA. Serum samples (n = 572) from patients with malignant (n = 326) as well as from healthy individuals (n = 246) were analyzed by the NCA-50/90 CLEIA and by the established ACCESS CEA assay. The average sensitivity of NCA-50/90 for malignant disease was 40.8%, compared to 45.4% of CEA. Relatively high positive rates of NCA-50/90 were observed in sera from patients with lung cancer (72.0%), hepatoma (62.5%), pancreatic cancer (47.6%), breast cancer (35.6%), and colorectal cancer (34.5%). About 15% of patients with malignant disease were positive only for NCA-50/90. The levels of NCA-50/90 and CEA in sera from patients with malignant disease correlated only poorly. CONCLUSIONS: The present study suggests that increases in blood levels of NCA-50/90 occur in a population of cancer patients which is different from those with elevated levels of CEA and that NCA-50/90 might be useful for NCA-50/90-positive, but CEA-negative patients.

Animals↗

PubMedDate not supplied

CD66a.

Explore the source record for details and available documents.

Animals↗