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Biomedical subjects

R C Seeger

Publications and source records attributed to R C Seeger.

At least 127 records · Page 7Linked to original sources
PubMed1985

Prognostic importance of serum ferritin in patients with Stages III and IV neuroblastoma: the Childrens Cancer Study Group experience.

Ferritin was measured in sera obtained at diagnosis from 241 patients with neuroblastoma to determine (a) the incidence of elevated ferritin and (b) the relationship between ferritin level and outcome. Ferritin was infrequently elevated in sera from patients with Stages I and II disease but was abnormally elevated in 37 and 54% of those with Stages III and IV neuroblastoma, respectively. The mean and median levels for each stage were compared and were highest for Stages III and IV disease. Analysis of progression-free survival for children with Stages III and IV disease indicated that elevated ferritin was associated with a significantly poorer prognosis than was normal ferritin and that this correlation was independent of stage and age at diagnosis. Progression-free survival at 24 months of follow-up for patients with Stage III disease with normal ferritin was 76% and with elevated ferritin was 23%. For those with Stage IV disease, progression-free survival was 27 and 3% with normal and elevated ferritin, respectively. We conclude that determination of the level of ferritin in serum at diagnosis is useful for selecting appropriate therapy for patients with Stage III neuroblastoma. Those with normal ferritin (63% of patients) have a good outcome with current therapy, but those with elevated ferritin (37%) do poorly and require more effective therapy. Although ferritin defines subgroups with Stage IV disease, the outcome of all groups must be improved.

Adolescent↗
PubMed1985

Analysis of neuroblastoma cell proteins using two-dimensional electrophoresis.

Polypeptide patterns of nine neuroblastoma and thirteen other cell lines were analyzed by 2-D PAGE. Of 600 polypeptide spots scored one was present in all neuroblastoma cell lines and none of the other cell types analyzed. Three were markedly increased in intensity in neuroblastoma relative to other cell lines, and one was markedly decreased in neuroblastoma and melanoma. These data provide a basis for a more detailed analysis of the polypeptide pattern of neuroblastoma cells.

Cells, Cultured↗
PubMed1984

Amplification of N-myc in untreated human neuroblastomas correlates with advanced disease stage.

A domain of DNA designated N-myc is amplified 20- to 140-fold in human neuroblastoma cell lines but not in cell lines from other tumor types. N-myc has now been found to be amplified in neuroblastoma tissue from 24 of 63 untreated patients (38 percent). The extent of amplification appears to be bimodal, with amplification of 100- to 300-fold in 12 cases and 3- to 10-fold in 10 others. Amplification was found in 0 of 15 patients with stage 1 or 2 disease, whereas 24 of 48 cases (50 percent) with stage 3 or 4 had evidence of N-myc amplification. These data indicate that N-myc amplification is a common event in untreated human neuroblastomas. Furthermore, N-myc amplification is highly correlated with advanced stages of disease (P less than 0.001) and with the ability to grow in vitro as an established cell line, both of which are associated with a poor prognosis.

Adolescent↗
PubMed1983

Raised neuron-specific enolase in serum of children with metastatic neuroblastoma. A report from the Children's Cancer Study Group.

Serum levels of neuron-specific enolase (NSE) were measured by radioimmunoassay at diagnosis in 122 children with widespread metastatic neuroblastoma (clinical stage IV). 96% of these patients had NSE levels more than three standard deviations above the mean for age-matched normal children. Mean serum NSE was 207 +/- SD257 ng/ml (range 10-1240 ng/ml), whereas that in normal age-matched children was 7.5 +/- 2.1 ng/ml (range 5.4-12.9 ng/ml). Analysis of survival in relation to the level of NSE at diagnosis suggested that serum levels greater than 100 ng/ml were associated with a poor outcome. This relation was highly significant in the subgroup of infants less than 1 year old at diagnosis; all 7 with serum NSE below 100 ng/ml were alive up to 36 months after diagnosis, whereas 7 of 8 with serum NSE above 100 ng/ml died within 12 months of diagnosis. Serum NSE may be a useful disease marker and a prognostic indicator in children with metastatic neuroblastoma.

Child↗
PubMed1983

Effects of retinoic acid (RA) on the growth and phenotypic expression of several human neuroblastoma cell lines.

It has been shown that retinoic acid (RA) can promote morphologic differentiation and inhibit the growth of a human neuroblastoma cell line, LA-N-1. The present study tests the histological generality of these phenomena by determining the effects of RA on seven other human neuroblastoma cell lines. Results show that RA strongly inhibited anchorage-dependent growth and induced morphologic alterations in six of seven of the cell lines. These alternations included morphologic differentiation as evidenced by formation of neurite extensions in four of the lines, cellular enlargement and vacuolization in one culture, and formation of large, flattened epithelial or fibroblastic-like cells in another culture. Although one cell line was relatively insensitive to the effects of RA in monolayer culture, all seven were strongly inhibited by RA in soft agar assays. Cellular RA-binding proteins were detected in 2/2 lines tested. These findings suggest that, as a histological group, human neuroblastoma cells are extremely sensitive to RA-induced growth inhibition and morphological alterations generally associated with reduced expression of the malignant phenotype of this type of cancer.

Axons↗
PubMed1982

Reversal of enterocolitis-associated combined immunodeficiency by plasma therapy.

Two 6-month-old male infants with diarrhea, malabsorption, and hypoproteinemia, who were initially diagnosed as having combined immunodeficiency syndrome, recovered with intensive plasma therapy. Prior to the onset of diarrhea, they had normal serum protein and lymphocyte values. Immunologic features of combined immunodeficiency included lymphopenia, diminished B and T cells, cutaneous anergy, low immunoglobulin levels, and poor lymphocyte proliferative responses in vitro. Prior to therapy, both children had rectal ulcerations by proctosigmoidoscopy, colitis by rectal biopsy, and moderate to severe intestinal villus abnormalities by small bowel biopsy; plasma cells were absent Both had generalized malabsorption of all nutrients. Both infants were given irradiated fresh-frozen plasma for one to two months at 11 to 20 ml/kg/day to replace intestinal protein losses. During this time, diarrhea slowed, biopsy morphology improved, and immunoglobulin levels and T-cell function became normal. After discontinuance of plasma therapy, normal immune function and a normal stool pattern with reversal of malabsorption continued. Since intensive plasma therapy may have contributed to the reversal of the immunodeficiency state, a trial of such therapy is recommended in similar patients.

B-Lymphocytes↗
PubMed1982

Neuroblastoma: clinical perspectives, monoclonal antibodies, and retinoic acid.

Neuroblastoma, the second commonest solid tumor in children, is a neoplasm of the peripheral autonomic nervous system that usually occurs before children are 6 years old. Therapy of localized tumor (clinical stage I and II) and of a special form of metastatic tumor (clinical stage IV-S) is usually successful, but treatment of widespread regional (clinical stage III) or metastatic (clinical stage IV) neuroblastoma is almost uniformly unsuccessful. Unfortunately, two thirds of children have stage III or IV disease at diagnosis. Several clinical trials are in progress. Preclinical investigations with monoclonal antibodies and retinoic acid may lead to new therapies. Monoclonal antibodies that react relatively selectively with neuroblastoma cells may be useful for diagnosis and therapy. Neuroblastoma cells have cytoplasmic retinoic-acid-binding proteins; treatment of cultured cells with retinoic acid induces morphologic maturation and markedly inhibits proliferation.

Antibodies, Monoclonal↗
PubMed1981

Common antigenic determinants on human melanoma, glioma, neuroblastoma, and sarcoma cells defined with monoclonal antibodies.

Antigenic determinants that are common to melanomas, gliomas, neuroblastomas, and sarcomas but that are minimally or not detectably expressed by adult tissues were defined with monoclonal antibodies. Quantitative absorption of monoclonal antibody (Ab 165) with adult tissues followed by testing on antigen-positive UCLA-SO-M14 melanoma cells did not demonstrate antigenic determinant (Ag 165) in brain, lung, liver, kidney, intestine, adrenal, and muscle, Absorption of Ab 376 demonstrated Ag 376 in adult lung but minimal or no antigen in other tissues. Both antigens were associated with a variety of fetal tissues. Assessment of 28 human tumor cell lines with the 131I-staphylococcal Protein A-binding test demonstrated that Ab 165 reacted strongly with melanomas and gliomas and weakly with sarcomas. Ab 376 reacted strongly with melanomas, gliomas, neuroblastomas, and sarcomas. Neither of these antibodies reacted appreciably with carcinoma or teratoma cell lines. Absorption of Ab 165 and Ab 376 with noncultured tumors demonstrated that melanomas, sarcomas, and neuroblastomas can have greater quantities of these antigens in vivo than do normal adult tissues. Qualitative and quantitative antigenic heterogeneity within positive classes of tumors was demonstrated for both cultured and noncultured tumors. The differences in antigen expression in vivo between normal and neoplastic cells suggest potential value for these antibodies in immunodiagnosis and possibly immunotherapy.

Antibodies, Neoplasm↗
PubMed1981

Analysis of human tumor cells for Ia-like antigens with monoclonal antibodies.

Cultured and noncultured human solid tumors were analyzed for expression of Ia-like antigens with the use of two monoclonal antibodies and a rabbit antiserum against human Ia-like antigens. Of 27 tumor cells tested, 3 melanomas bound antibodies [e.g., 21,563 cpm 131I-labeled staphylococcal protein A ([131I]SpA) with monoclonal antibody Q5/6], but 24 others (1 melanoma, 9 neuroblastomas, 1 medulloblastoma, 3 gliomas, 4 sarcomas, 2 colon carcinomas, 2 transitional cell carcinomas of the bladder, 1 teratoma, and 1 squamous cell carcinoma of the lung) did so minimally or not at all (0-427 cpm [131I]SpA with antibody Q5/6. Monoclonal antibody Q5/6 was quantitatively absorbed with homogenates of 32 noncultured tumors to determine if Ia-like antigens were expressed by neoplastic cells in vivo. Ten milligrams (wet wt) each of 5 of 7 noncultured melanomas removed more than 83% (median, 85%) of the antibody. In contrast, 10 mg each of 10 neuroblastomas, 7 carcinomas, 4 sarcomas, and 4 Wilms' tumors removed less than 47% (median, 19%) of the antibody; even 100 mg of these tumors removed less than 68% (median, 44%) of the antibody.

Antibodies↗
PubMed1980

Volumetric and functional heterogeneity of human monocytes.

Volume analysis of purified human blood monocytes revealed distinct populations of large and small cells. Computer curve fitting suggested a third, intermediate-sized population. These monocytes were designated M1, M2, and M3 in order of increasing size, and their approximate volumes were 150, 250, and 480 micron3, respectively. The three subpopulations were present in all 30 normal individuals tested. Two new techniques were developed that separate monocytes into M1 + M2 and M3 fractions; one used preferential incorporation of carbonyl iron particles by M3 cells and the other used the selective aggregation of M3 cells by thrombin in the presence of platelets. The chemotactic response to zymosan-activated human serum by total monocytes, M1 + M2 monocytes, and M3 monocytes was determined by the agarose plate method. In all experiments M3 monocytes were 10-fold more responsive than M1 + M2 monocytes and were significantly more so than total monocytes. These findings suggest that M3 cells are the major subpopulation capable of directional migration. This investigation establishes the existence of volumetrically definable subpopulations of human monocytes that are functionally distinct.

Cell Separation↗
PubMed1980

Abnormal B cell differentiation and variable increased T cell suppression in immunodeficiency with hyper-IgM.

In vitro immunoglobulin (Ig) synthesis was evaluated in three young men having immunodeficiency with hyper-IgM. Patient and normal T and B cells were separated and cultured in various combinations. 35S-methionine incorporation into Ig was measured using immunoprecipitation, and Ig classes were determined by SDS-polyacrylamide gel electrophoresis with autoradiography. The patient B cells were able to produce only IgM in culture with either autologous or allogeneic T cells. Normal B cells produced IgM, G and A when cultured with normal T cells. T cells from two of the patients suppressed the Ig synthesis of normal B cells; irradiation of these T cells allowed them to provide T helper function. T cells from the third patient expressed normal T suppressor/helper activity. This implies that defective differentiation of B cells into IgG- and IgA-producing plasma cells may be a constant feature of immunodeficiency with hyper-IgM, and that excessive T suppressor activity is a variable accompanying abnormality.

Adult↗
PubMed1980

Variability in DNA distributions of human neuroblastomas after cyclophosphamide.

Major changes in DNA distributions of two human neuroblastoma cell lines growing in vitro and in athymic nude mice occurred after treatment with cyclophosphamide. Pulse treatment of LA-N-1 cells in vitro with liver S-9-activated cyclophosphamide (10 micrograms/ml) caused approximately 50% cytotoxicity; flow microfluorometric analysis of surviving cells demonstrated an increased proportion of G2 + M cells and a decreased proportion of G1 cells, particularly at 48 hrs. Even though LA-N-1 tumors in nude mice did not regress after one dose of cyclophosphamide (250 mg/kg), the percent of G2 + M cells increased and the percent of G1 cells decreased 4-6 days after treatment; the percent of cells in S increased at 2 and again at 8 days. SK-N-MC cells were affected differently by cyclophosphamide. Pulse treatment of these cells in vitro with liver S-9-activated cyclophosphamide caused greater than 85% cytotoxicity and nearly complete elimination of cells in G2 + M at 24 and 48 hrs. Likewise, SK-N-MC tumors in nude mice regressed greater than 50% after cyclophosphamide, and the proportion of G2 + M cells decreased markedly 2-6 days after therapy. We conclude that cyclophosphamide can have different cytotoxic and cytokinetic effects on neuroblastomas. In addition, marked cytokinetic effects may occur even though changes in tumor size are minimal or not detectable.

Animals↗