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Biomedical subjects

D Bellet

Publications and source records attributed to D Bellet.

At least 127 records · Page 7Linked to original sources
PubMed1983

Production and in vitro utilization of monoclonal antibodies to human thyroglobulin.

Human thyroglobulin (Tg) was used as an antigen in the development of antibodies by the hybridoma technique. From four antibodies that bound more than 40% labeled Tg, two were characterized (182/E4 and 211/A5). They were both of the immunoglobulin G 2ab subclass, and provided an affinity constants (Ka) of 1.2 X 10(10) and 7.7 X 10(9) mol-1, respectively. The specificity of these antibodies was demonstrated by the absence of cross-reaction by monoiodothyronine, diiodothyronine, T3, T4, and sialic acid. A RIA was developed with 182/E4 or 211/A5, and the least detectable dose, based on the standard curve, was 10 ng/ml. The immunoreactivities of 182/E4 and 211/A5 to four Tg preparations different in iodine content appeared to be identical. Histochemical staining was used on normal and neoplastic tissues with both antibodies. Positive reactions were obtained in both cells and colloid, with heterogeneous staining from one follicle to another. Papillary carcinoma showed numerous positive cells, in contrast with Hürtle cell tumors which displayed very few positive cells. Anaplasic giant and spindle cells were negative. Monoclonal antibodies to human Tg are useful for in vitro detection of Tg.

Animals↗
PubMed1983

[Relapses of malignant nonseminomatous germinal testicular tumors].

18 relapses of non seminomatous germ cell cancer of the testis are studied, among a group of 112 patients treated from 1974 to 1978, of which 90 are in complete remission. The study of these cases shows the bad prognosis value of yolk sac tumor component at histological examination. Relapses are more frequent in the stages with lymph node involvement treated by retroperitoneal lymphadenectomy followed by chemotherapy without cis-platinum. Cis-platinum chemotherapy decreases relapse rate in theses stages and increases complete remission rate in metastatic stages.

Cisplatin↗
PubMed1983

[Primary retroperitoneal malignant germinal tumors in man].

Primary retroperitoneal malignant germinal tissue tumors were detected in 9 male subjects. Normally diagnosed at a late stage because of their localization, excision of these tumors is usually impossible, but in 8 of the 9 cases of this personal series diagnosis was possible without laparotomy by assay of biological markers: hCG and foetoprotein. The size of the tumors prevents their eradication by radiotherapy, but chemotherapy has become effective since the employ of cis-platinum and bleomycin by continuous infusion, and secondary surgery can then be performed. None of these patients had a testicular tumor.

Adolescent↗
PubMed1982

Gonadotrophin-producing seminoma: a distinct category of germ cell neoplasm.

Gonadotrophin-producing seminomas can be identified in two ways: detection of human chorionic gonadotrophin (HCG) in the serum or urine, or histological identification of syncytiotrophoblastic giant cells, which can be shown to contain HCG by means of indirect immunoperoxidase techniques. A review of the histories of 14 patients with such tumours shows that they are associated with a worse prognosis than that of 'typical' seminomas, and tend to present with a more advanced stage of disease. These tumours are thus distinct, clinically and biologically, from typical seminomas, and their treatment needs to be planned accordingly.

Chorionic Gonadotropin↗
PubMed1982

[Cerebral metastases of malignant germinal tumors of the testis].

Cerebral metastases occur in 6% of cases of testicular cancer. In our study of 5 cases they occurred during the course of the disease (with a delay of 4-18 months, at the same time as pulmonary and abdominal metastases). The prognosis in these cases is poor (presence of choriocarcinomatous or vitelline elements, advanced stages). The diagnosis is easily established (clinical, encephalogram, scanner); the prognosis is hopeless (5 deaths in 3-90 days). When a metastasis is the first diagnostic clue (one case), the prognosis is slightly better (9 month survival). The incidence of cerebral metastasis is the same now as it was before the introduction of effective chemotherapy in patients who die from testicular cancer, but the death rate from this malignancy has decreased since the introduction of active chemotherapy with cisplatin. Hence, there is no indication for prophylactic treatment for cerebral metastases in patients in remission since metastases only appear in cases which are resistant to treatment.

Abdominal Neoplasms↗
PubMed1982

[Factors of severity in placental choriocarcinoma].

A retrospective study has been carried out on the poor prognostic features of a group of 57 patients. These are: the existence of extra-pelvic and extra-pulmonary metastases and a level of serum HCG above 200000. The most favourable prognostic signs are absence of these two factors in pregnancy that is not normal and a delay between the onset of the first diagnostic elements and treatment of less than 6 months.

Adolescent↗
PubMed1981

[Biological markers for tumours of the testis. Their use in diagnosis, prognosis and follow-up in 200 cases (author's transl)].

Repeated measurements of serum chrionic gonadotrophic hormone (CGH), of its beta sub-unit (beta CGH) and of alpha-foetoprotein (aFP) were performed in 200 patients with germinal tumours of the testis. CGH levels were found to be high in 43,5% of patients, particularly those with choriocarcinoma (a rare tumour) or with embryonal carcinoma with syncytiotrophoblastic (ST) cells. They were also high in 24% of patients with histologically pure seminoma, which throws doubts on the homogeneity of this group of tumours and raises problems concerning their treatment in patients with high CGH. aFP levels were increased in 38% of all patients, particularly those with ST cell embryonal carcinoma (62%) or with malignant teratoma (56%). These biochemical markers may point to a histological diagnosis. They also have prognostic value and are essential for monitoring during treatment. Pre-operative assays are to particular interest and should be performed in every case.

Adult↗
PubMed1981

[Immunoperoxidase study of 80 germ cell tumours of the testis in adults (author's transl)].

Twenty-six tumours of the seminoma type and 54 embryonic carcinomas of the testis were studied with immunoperoxidase, using an anti-beta HCG immune serum and an anti-alpha FP immune serum. The results obtained in first group suggest the possibility of a new type of "pseudo-seminoma" tumours, with high levels of circulating HCG probably due to proliferation of trophoblasts. In the second group, 88% of the tumours gave positive response to one or the other immune sera. However, the anti-alpha FP-positive structures were similar to those of pure vitelline tumours, and the anti-beta HCG-positive structures were syncytiotrophoblastic elements different from those of conventional carcinomas. The combined results of histology, immunohistochemistry and pre-operative biological tests should lead to improved identification of malignant germ cell tumours of the testis.

Chorionic Gonadotropin↗
PubMed1978

[Biorheologic study of pathological synovial fluids].

Rheometric studies of 34 synovial fluids done using a rheometer with a cone and stage (Shirley-Ferranti type) showed that arthrotic synovial fluids had pseudoplastic characteristics (non-Newtonian) but in inflammatory rheumatisms, the characteristics index rises, the consistency decreases and the fluid tends to loose its pseudoplastic properties and to become Newtonian. Radioisotope synoviorthosis seems capable of restoring to a certain extent and in certain cases the rheometric characteristics of the pseudoplastic properties.

Adolescent↗
PubMedDate not supplied

Immune recognition of a molecule naturally presented as a monomeric or an oligomeric structure: the model of the human chorionic gonadotropin alpha subunit.

The immune recognition of a molecule naturally presented as a monomeric or an oligomeric structure is analyzed using the human chorionic gonadotropin alpha subunit (hCG-alpha) as a model. Indeed, hCG-alpha circulates as either a free subunit or combined to the beta subunit (hCG-beta) to form the dimeric hCG hormone. A T cell study was performed in BALB/c (H-2d) mice which were found to be high responders to hCG-alpha. Mice were immunized with the free hCG-alpha or the dimeric hCG alpha/beta, and their lymph node cells were challenged in vitro with either alpha subunits from different species, hCG or peptides spanning the entire primary structure of hCG-alpha. Proliferation and IL-2 assays demonstrated that hCG-alpha-primed lymph node cells responded equally well to hCG-alpha and hCG alpha/beta, suggesting that both the free and combined hCG-alpha subunits are processed in a similar way. Among the various synthetic peptides used, only those mimicking the hCG-alpha(59-92) C-terminus portion were able to stimulate hCG-alpha-primed lymph node cells, demonstrating that this region contains immunodominant T cell recognition site(s). The hCG-alpha(23-43) and (32-59) peptides, although incapable of stimulating T cells primed with hCG-alpha, elicited a T cell response when used as immunogens. These regions encompassed cryptic epitopes which were not generated during hCG-alpha processing in H-2d mice. The T cell epitopes of hCG-alpha above described as immunodominant or cryptic on the free alpha subunit, had similar characteristics when the alpha/beta dimer was used as the immunogen. In contrast, T cells primed with peptides mimicking immunodominant sites recognized differently the hCG-alpha and the hCG alpha/beta antigens. Moreover, the analysis of the B cell response to all the immunogenic hCG-alpha peptides indicated that they bear B and T cell epitopes as well. Antibodies elicited against the hCG-alpha(59-92) or (32-59) peptide were capable of recognizing the alpha subunit in its free form but not in the alpha/beta hCG dimer. Such study deserves attention for the comprehensive mechanisms of the immune response to hCG as well as for the design of anti-hCG vaccines.

Amino Acid Sequence↗
PubMedDate not supplied

A gamma-chain complex forms a functional receptor on cloned human lymphocytes with natural killer-like activity.

We have recently derived from human fetal blood (25 wks) a series of cloned cell lines that were selected for their ability to kill the conventional natural killer (NK) target cell K562. It was found that a fraction of these clones express CD3 proteins but not the monomorphic Ti alpha beta determinant recognized by WT31 antibody. One interleukin-2-dependent CD3+ WT31- clone, termed F6C7, was used for immunization of mice to generate monoclonal antibodies directed at a potentially novel recognition receptor. It was shown that F6C7 cells, which transcribe Ti beta but not Ti alpha genes, surface-express a clonotypic structure, termed NKFi. Immunoprecipitations performed with anti-NKFi monoclonal antibody (mAb) indicated that the corresponding molecule is resolved in SDS-polyacrylamide gel electrophoresis (PAGE) as a single band of relative molecular mass approximately 85,000 (Mr approximately 85K). After reduction, a major band was detected at 44K and a faint band was present at 41K. The present study was designed to characterize this structure. It was found that NKFi represents either two 44K disulphide-linked gamma (TCR) chains, or possibly one gamma chain associated to an additional undetected molecule, and that the 41K material corresponds to a partially glycosylated fraction of the gamma protein. Anti-NKFi mAb both induces a specific autocrine proliferative response and blocks cytotoxic function, demonstrating that gamma chains serve as functional receptor structures on subpopulations of normal human lymphocytes.

Antibodies, Monoclonal↗
PubMedDate not supplied

Maternal serum screening for chromosome defects: human chorionic gonadotropin versus its free-beta subunit.

The addition of maternal serum intact hCG (MShCG) to routine maternal serum alpha-fetoprotein screening for Down's syndrome is expected to yield a detection efficiency around 60% for an amniocentesis rate approximating 5%. We compared the detection rate using intact MShCG and free-beta hCG in 480 normal pregnancies and 48 with chromosome defects (Down's syndrome 31, other chromosome defects 17). No significant difference in detection efficiency was determined. However, since the false-positive rate with free-beta hCG was almost twice that found with intact hCG, and the detection rate for other chromosome defects was more than double, the intact MShCG assay is currently preferred. Free-beta hCG earlier in gestation may, however, ultimately prove superior in maternal screening for chromosome defects.

Adult↗