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Biomedical subjects

I Magrath

Publications and source records attributed to I Magrath.

At least 73 records · Page 4Linked to original sources
PubMed1989

Immunological phenotypic pattern of acute lymphoblastic leukaemia in Egypt.

We have performed immunophenotyping studies on 186 untreated cases of acute lymphoblastic leukemia (ALL) in an Egyptian population, using panels of monoclonal antibodies (mAb) and an avidin-biotin-immunoperoxidase detection system. Sixty-two of these cases were tested with a panel of mAb directed against the T-cell markers CD2, CD4, CD8, B-cell markers CD20, kappa and lambda, the common ALL antigen (common ALLa) and class II HLA antigens. The remaining 124 cases were also tested with additional markers of T- and B-cell precursors, namely CD7 and CD19. The common leukocyte antigen, T200, was used to exclude nonhemopoietic neoplasms. Cases that remained unclassifiable were further tested with a wider panel of T-cell markers, including CD1, CD2, CD3 and CD5. In some cases multiple mAb directed against the same antigens were used. The relative frequencies of common ALL and B ALL were calculated from the total number of cases and were found to be 39.2% and 3.2%, respectively. The proportions of T-cell and null leukemias were calculated from the better characterized subgroup of 124 cases, and were found to be 50% and 4.8%, respectively. In our series, the age distribution of common ALL revealed a peak at 2-5 yr, but this was partially obscured in the entire series by the high proportion of T-cell cases, which had an age peak between 4 and 12 yr of age. Our results demonstrate marked differences in the phenotypic pattern of ALL in Egypt compared to Western Countries, the predominant finding being a relative excess of T-cell ALL and a paucity of common ALL cases. At present it is not clear whether this results from an increased incidence of T-cell ALL or a decreased incidence of common ALL.

Adolescent↗
PubMed1988

The molecular analysis of chromosomal translocations as a diagnostic, epidemiological and potentially prognostic tool in lymphoid neoplasia.

Neoplasms have been shown to be associated with specific non-random chromosomal abnormalities. The present paper summarizes molecular consequences of chromosomal translocations in lymphoid malignancies, especially in Burkitt's lymphoma. Among such consequences are derangements of the regulation of oncogene transcription. Besides their possible importance for lymphoma pathogenesis, chromosomal translocations are associated in some lymphoid neoplasms with a worse prognosis.

Burkitt Lymphoma↗
PubMed1987

Ifosfamide with mesna uroprotection and etoposide: an effective regimen in the treatment of recurrent sarcomas and other tumors of children and young adults.

One hundred twenty-four children and young adults with recurrent tumors, predominantly sarcomas, were treated with the combination of ifosfamide, etoposide, and the uroprotector, mesna (2-mercaptoethane sulphonate), in a phase II trial. The treatment regimen consisted of 12 cycles of therapy administered every 3 weeks. After evaluation of the tumor response to chemotherapy alone, radiation or surgery was used to eradicate residual sites of metastatic disease where possible. At the present time, 77 patients are evaluable for response to the chemotherapy; 43 of the patients have experienced a significant reduction in the tumor size in response to the chemotherapy alone (39 partial responses [PR] and four complete responses [CR]). Sixteen of 17 patients with Ewing's sarcoma, nine of 13 with rhabdomyosarcoma, four of eight with peripheral neuroepithelioma, three of eight with osteosarcoma, and 11 of 31 with other tumors have responded with a PR or CR. The toxicity of the regimen was acceptable. Moderate or severe toxicity evaluated on a per cycle basis included: neutropenia, 97%; thrombocytopenia, 32%; nephrotoxicity, less than 1%; mucositis, 1%; neurologic toxicity, 2%; nausea and vomiting, 13%; hemorrhagic cystitis, less than 1%. Fever was present after 33% of cycles and sepsis following 7%. One patient died due to sepsis and pancytopenia. At the present time, only seven of the 43 patients who responded to the chemotherapy regimen have relapsed, with a median follow-up of 10 weeks after the response. This drug combination is highly active in the treatment of recurrent sarcomas and other tumors in children and young adults.

Adolescent↗
PubMed1986

A phase II study of ifosfamide in the treatment of recurrent sarcomas in young people.

We have evaluated the activity of ifosfamide in 75 patients with recurrent sarcomas and pediatric solid tumors. All patients had previously received cyclophosphamide in combination with other chemotherapeutic agents. Ifosfamide was administered as a continuous 5 day infusion at a dose of 1800 mg per M2, except in the last 14 patients who received the drug as a daily one hour infusion at the same dose level. Partial response was observed in 9 of 20 patients with Ewing's sarcoma, 2 of 9 patients with rhabdomyosarcoma, 3 of 17 patients with osteogenic sarcoma and 4 of 29 patients with various other neoplasms. A further 6 patients had stable disease, defined as the absence of progression for at least 6 cycles of therapy. Thus overall response rate was 24%, with the highest response rate of 45% being observed in Ewing's sarcoma. Toxicity was acceptable, although there was quite marked leucopenia (median nadir 700) with less profound thrombocytopenia (median nadir 87,000). Sepsis occurred in 3 patients but no patient died as a result of infection. Hematuria occurred in 43% of patients who did not receive mesna, and in 26% of patients who did, although prior pelvic irradiation was found to be a significant risk factor for hematuria. Only 1 of 14 patients without prior pelvic irradiation or hematuria developed hemorrhagic cystitis when treated with ifosfamide and mesna. Confusional states developed in 6 patients. We conclude that ifosfamide is an active agent in patients with relapsed sarcomas and childhood solid tumors, even when such patients have been previously treated with cyclophosphamide.

Adolescent↗
PubMed1986

Chromosomal breakpoints and structural alterations of the c-myc locus differ in endemic and sporadic forms of Burkitt lymphoma.

We have examined the position of the chromosomal breakpoint relative to the human c-myc gene (MYC) and the presence of other structural alterations of the same locus in 19 fresh samples of Burkitt lymphoma (BL) and 13 BL-derived cell lines. This panel includes the two pathogenetic forms of BL: the endemic (African-type) BL (eBL) and sporadic (American-type) BL (sBL). In all cases tested, including fresh samples and cell lines, structural alterations of the 5' portion of the gene were detected, suggesting that they may be necessary for c-myc activation. However, the site of chromosomal breakpoint and the type of structural alterations differ in eBL and sBL. In 16 of 18 sBL cases, chromosomal translocation truncates the gene within a 5' region that includes the first intron, the first exon, and 5' flanking sequences. Conversely, in 14 of 14 eBL samples, the chromosomal breakpoint is located outside the c-myc locus, yet the same 5' sequences are affected by several mutations identifiable by restriction enzyme polymorphisms. Different genetic mechanisms may therefore be involved in chromosomal translocation/c-myc activation, and these differences may be a function of differences in the stage of differentiation of eBL versus sBL.

Burkitt Lymphoma↗
PubMed1986

Expression of surface antigens during the cell cycle in different growth phases of American and African Burkitt's lymphoma cell lines.

We have studied the expression of five surface antigens in eight Burkitt's lymphoma cell lines during different phases of the cell cycle and in different growth phases (logarithmic and stationary). Cells were stained simultaneously for surface antigens (fluorescein coupled antibodies) and DNA content (propidium iodide), and dual parameter measurements were performed with a flow cytometer. Analysis of cells in specific cell cycle phases during log-phase growth revealed a 1.6-fold increase in surface antigen expression as cells passaged from G1 to G2/M. This is almost identical to the measured increase in cell surface area which occurs during passage of cells through the cell cycle and indicates that under optimal conditions surface antigen density is maintained during cell doubling. We also observed a consistent reduction, by about 50%, in the expression of surface IgM (mu), k-light chain, and B1 on the cell lines during a 5-day culture period. Cell lines that only weakly expressed surface IgM were found to have a more rapid decrease, and in such cell lines IgM was ultimately completely lost from the cell surface. In contrast, the expression of beta 2-microglobulin and HLA-ABC increased in some cell lines, whereas in others a significant decrease of both beta 2-microglobulin and HLA expression was demonstrated as the cells entered stationary growth phase. Decreased cell volume (and therefore surface area) associated with declining growth rate and fewer late S or G2/M cells could account for 20-30% of the observed reduction in surface IgM, k-light chain, and B1 expression, but the major decrement in fluorescence intensity was due to a reduction in the density of these surface antigens. Thus, the ability to maintain surface antigen densities is frequently lost in suboptimal culture conditions.

Africa↗
PubMed1985

Chromosomal orientation of the lambda light chain locus: V lambda is proximal to C lambda in 22q11.

We have demonstrated that the chromosomal breakpoint at 22q11 of a Burkitt lymphoma cell line (PA682) with an 8;22 translocation interrupts the variable region of the lambda light chain locus. In these cells, all of the C lambda and some V lambda sequences translocate to the 8q+ chromosome whereas some V lambda sequences remain on the 22q-. These results indicate that the lambda light chain locus on the long arm of chromosome 22 is oriented such that V lambda is proximal to C lambda.

Burkitt Lymphoma↗
PubMed1983

Synthesis of kappa light chains by cell lines containing an 8;22 chromosomal translocation derived from a male homosexual with Burkitt's lymphoma.

Three cell lines were derived from a homosexual patient with probable acquired immunodeficiency syndrome and Burkitt's lymphoma. The cell lines produce an unusual strain of Epstein-Barr virus which will both transform cord blood lymphocytes and induce early antigens in Raji cells. Translocations between chromosomes 8 and 22 have occurred in all three lines, but the cells synthesize immunoglobulin M with light chains of the kappa type, in contrast to the usual concordance between a translocation involving chromosome 22 and lambda chain synthesis. Both kappa genes and one lambda gene are rearranged. These findings indicate either that translocation may occur as a separate event from immunoglobulin gene rearrangement or that the proposed hierarchical sequence of immunoglobulin gene rearrangements is not always adhered to. The data also imply that in cells containing a translocation between the long arm of chromosome 8 and a chromosome bearing an immunoglobulin gene, alteration of cellular myc expression may occur regardless of the immunoglobulin gene that is expressed.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Central nervous system involvement in American Burkitt's lymphoma.

Sixty-four patients with American Burkitt's lymphoma (AMBL) treated at the National Cancer Institute were reviewed to determine the frequency and characteristics of central nervous system (CNS) involvement. Patients with minimal or completely resected tumor never had CNS disease. Of the 45 patients with more extensive disease, 15 had CNS disease: nine presented with CNS disease, six of whom subsequently had recurrent CNS disease, and six developed CNS disease only at relapse. There was a significant association between CNS and bone-marrow disease at presentation. Therapy of CNS disease consisted of short courses of intrathecal chemotherapy with cytosine arabinoside and methotrexate. Cranial irradiation was given only to patients with CNS relapse. There are six long-term survivors (LTS) who have been disease free for four to six years post chemotherapy. Of these six LTS, three presented with CNS disease, two experienced isolated CNS relapse, and one had CNS disease both at presentation and at relapse. Three of the six LTS never received cranial irradiation. It is concluded that CNS involvement in AMBL can be effectively treated, and that long-term remission, which is probably cure, can be achieved.

Adolescent↗
PubMed1983

Diversity of immunological phenotypes of lymphoblastic lymphoma.

Eleven cases of lymphoblastic malignancy, presenting as lymphoma, were investigated for immunological and differentiation markers prior to the onset of therapy. Biopsy specimens exhibited the typical morphological features of lymphoblastic lymphoma (convoluted T-cell lymphoma). Intranuclear terminal deoxynucleotidyl transferase was detected in the neoplastic cells from each case by indirect antibody staining of cytocentrifuge preparations. Eight cases were T-cell type as evidenced by unsensitized sheep erythrocyte rosette formation and staining with the monoclonal antibody OKT11. Three T-cell cases were OKT4 positive, two were OKT8 positive, and none were positive with both OKT4 and OKT8. Three cases failed to react with any monoclonal antibodies specific for T-cells and did not form unsensitized sheep erythrocyte rosettes or stain for surface immunoglobulin. However, these three cases were Ia positive and J5 (common acute lymphoblastic leukemia antigen) positive. Cells from two of these erythrocyte rosette-negative, Ia-positive, common acute lymphoblastic leukemia-positive cases contained intracytoplasmic mu heavy chains and were therefore of pre-B-cell phenotype. These cases were histologically indistinguishable from the T-cell cases. However, clinically, they were distinguished by the absence of mediastinal masses and by a clinical presentation as isolated lytic lesions of bone in two of the three. OKT9 and OKT10 stained neoplastic cells from T-cell, as well as pre-B-lymphoblastic, lymphoma. Although morphologically homogeneous, lymphoblastic lymphomas are comprised of an immunologically diverse group of neoplasms which include cells of "common" and "mature" thymocyte, non-T, non-B, and pre-B phenotypes and are closely related to the cells of acute lymphoblastic leukemia. In addition, intratumor heterogeneity was observed in most instances and may reflect growth or differentiation differences between subpopulations of individual neoplastic clones.

Adolescent↗
PubMed1983

Serum monoclonal immunoglobulin bands in undifferentiated lymphomas of Burkitt and non-Burkitt types.

Using an improved electroimmunofixation technique that combines the sensitivity of high resolution agarose gel electrophoresis with the specificity of immunoprecipitation, we have demonstrated monoclonal immunoglobulin bands in the serum of patients with undifferentiated lymphomas of Burkitt and non-Burkitt types. Monoclonal bands were detected in the serum of 12 of 21 patients with extensive tumor, and 1 of 10 patients with minimal tumor. All of the bands were identified as IgM of a single light chain class. Such bands were not detected in the serum of patients with lymphoblastic lymphoma (7) or African Burkitt's lymphoma (6). There was disappearance of the bands after therapy and reappearance at relapse. These findings, coupled with previously reported in vitro information, indicate that undifferentiated lymphoma cells secrete immunoglobulin of IgM isotype. Therefore, such monoclonal bands may be of potential value as tumor markers.

Adolescent↗
PubMed1982

The American Burkitt's Lymphoma Registry: eight years' experience.

Four-hundred-twenty-one Americans diagnosed as having Burkitt's lymphoma (BL), 409 from the United States, were studied by the American BL Registry to obtain information about the cause and control of this disease. Of these 421 cases, 256 were confirmed by our pathologists as being morphologically indistinguishable from African BL, A relationship between age and organ involvement was observed; cervical lymph nodes, ileum, and nasopharynx were initial sites of involvement primarily in younger patients. Although the Epstein-Barr virus (EBV) was less frequently associated with American BL than African, a high antibody titer to the EBV capsid antigen was associated with a more favorable prognosis. American BL resembled African BLs time-space clustering, male predominance, and excellent response to chemotherapy. Unlike African BL, however, more patients had involvement of cervical lymph nodes and bone marrow at an early stage of disease. American BL appears to be a more heterogeneous disease than African BL.

Adolescent↗
PubMed1982

Persistence of transforming and nontransforming Epstein-Barr virus in high passages of P3HR-1 cell lines.

At least three laboratories have reported that the P3HR-1 line, which had originally produced transforming Epstein-Barr virus (EBV), now produces only the nontransforming variant. Studies to determine whether these findings were universal or a consequence of specific cell lines or culture conditions were undertaken in P3HR-1 cultures of identical HLA types from five sources. All of the EBV preparations derived from cell lines cultured at 32, 34, and 35 degrees C transformed cord blood lymphocytes, whereas virus propagated at 37 degrees C did not usually transform. Furthermore, indirect immunofluorescence revealed that a monoclonal antibody directed against transforming EBV membrane glycoprotein bound to 10-12% of the P3HR-1 cells that had been continuously propagated at 34 degrees C, but the antibody did not bind to the same cells cultured at 37 degrees C. Although virus expression was completely repressed in transformed cord blood cells, transforming virus could be rescued by superinfection with nontransforming P3HR-1 EBV. Cells transformed with P3HR-1 virus induced poorly differentiated lymphomas in athymic nude mice after seven or eight passages. Whether all P3HR-1 cells have the potential to produce detectable quantities of transforming virus remains to be determined.

Animals↗