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Biomedical subjects

B Ramot

Publications and source records attributed to B Ramot.

At least 37 records · Page 2Linked to original sources
PubMed1992

Superior vena cava syndrome associated with lymphoma.

OBJECTIVE: To evaluate the workup and treatment of children with lymphoma and superior vena cava syndrome. DESIGN: A retrospective survey. SETTING: State hospital serving as a secondary and tertiary referral center for pediatric oncology and pediatric cardiac surgery. PARTICIPANTS: Eleven children aged 11 months to 12 years diagnosed as having lymphoma or T-cell acute lymphoblastic leukemia who presented with superior vena cava syndrome during an 11-year period. INTERVENTIONS: Lymph node biopsy (two patients), thoracenthesis (five patients), bone marrow aspiration (two patients), and thoracenthesis in addition to bone marrow aspiration (two patients). All aspirates were evaluated with immunohistochemical studies. Chemotherapy was the only management intervention. RESULTS: T-cell lymphoma or leukemia accounted for nine cases and Hodgkin's disease for two cases. Respiratory symptoms occurred in 10 patients, including tracheal compression in six patients (compression was life-threatening in one patient). Diagnosis of superior vena cava syndrome was achieved in eight patients using surface-marker analysis of aspirates. The syndrome disappeared within 2 to 10 days. Seven of nine children whose conditions were diagnosed more than 1 year before this writing were alive and free of disease after mean follow-up of 37 months. CONCLUSIONS: (1) A specific diagnosis can be achieved in most children with superior vena cava syndrome and lymphoma; (2) Thoracic computed tomographic scans are essential, identifying minute pleural effusions that can aid diagnosis; (3) Anesthetic hazard is related only to severe tracheal compression; (4) Chemotherapy achieves excellent symptomatic relief; and (5) Long-term survival, without disease, is achievable.

Child↗
PubMed1992

The management of pediatric brain tumors in a tertiary center.

Between January 1982 and January 1990, 120 newly diagnosed pediatric patients were treated at The Chaim Sheba Medical Center. Sixty three (52.5%) tumors arose in the posterior fossa and 57 (47.5%) appeared supratentorially. A wide variety of histologic subtypes was seen, each requiring tumor-specific treatment. The modern imaging techniques-CT and MRI-offered better planning of operation, treatment and follow up. All children with highly malignant tumors were treated with combination chemotherapy besides the 'conventional radiotherapy'. Since 1987 the "eight in one day" protocol has been used extensively pre- and post-irradiation. Five-year survival, varied significantly according to tumor type, location and stage. The average delay from presentation of symptoms to diagnosis was 6 months. A multidisciplinary approach has been used in the treatment, rehabilitation and follow-up of these children. In this study, the results of treatment are presented and the role of chemotherapy is discussed.

Adolescent↗
PubMed1992

Detection of adeno-associated virus type 2 in human peripheral blood cells.

The non-pathogenic human parvovirus, adeno-associated virus (AAV) is helper virus-dependent. However, it integrates into the cellular genome in the absence of its helper viruses. Therefore it could become a useful vector for gene therapy. Previous studies and our own results have shown that 40 to 80% of adults are seropositive for AAV and that seroconversion occurs during the first few years of life, but little is known about the route of natural infection with the virus. We used the polymerase chain reaction to detect the AAV-2 genome and identify AAV sequences within peripheral blood leukocytes (PBLs). We could detect AAV in PBLs of two of 55 healthy blood donors, and two of 16 haemophilic patients. AAV DNA replication and viral protein production in PBLs propagated in tissue culture were also examined. AAV DNA replicated very efficiently in the presence of helper adenovirus, but capsid proteins were produced at a lower level and the yield of infectious virus was very low. Our findings prove that in vivo infection of PBLs occurs, and that PBLs could mediate the spread of AAV infection to different body tissues.

Capsid↗
PubMed1992

Structural organization of the murine c-kit proto-oncogene.

The murine Kit receptor gene on chromosome 5 has been found to be frequently involved in germline mutations and rearrangements, leading to a characteristic set of severe developmental defects, known as the W phenotype. Here we describe the structure of the murine c-kit gene, based on restriction analysis of genomic phage clones and sequence determination of exon-intron boundaries. The Kit-coding region is distributed over 21 exons, most of which have sizes that range between 100 and 200 base pairs. The 3' non-translated sequence and the 3' end of the coding region form a single large exon, which encompasses 2.3 kb and is flanked by polyadenylation signals. The entire region spans a genomic distance of at least 70 kb. Though the exonic demarcations of c-kit show remarkable similarity to those of the human c-fms gene (which encodes the highly related colony-stimulating factor 1 receptor), no correlation could be found between the sizes of introns that separate homologous exon pairs. The data suggest that evolutionary pressures were confined to the conservation of structures of coding exons, whereas flanking regions were subject to large changes, owing to insertions and deletions. Finally, the analysis of the Kit genomic structure reveals that the inherited mutations of the Kit gene that have been reported thus far occur at various dispersed positions within the gene. Hence, the entire gene appears to have as yet unknown features which cause it to be frequently subject to mutations in murine germline tissues.

Amino Acid Sequence↗
PubMed1991

Identity of rearranged LINE/c-MYC junction sequences specific for the canine transmissible venereal tumor.

The canine transmissible venereal tumor is a naturally occurring neoplastic disease that affects the external genitalia of both sexes and is transmitted during coitus. Cytogenetic and immunologic studies demonstrated that tumors from different parts of the world are very similar, suggesting that they are transferred from one animal to another by the transplantation of viable cells. We found that the c-MYC oncogene was rearranged in this tumor by the insertion of a transposable genetic element sequence (known as LINE, long interspersed element) 5' to the first exon. The amplification of a DNA segment located in the junction of the LINE genome and c-MYC upstream sequences enabled the testing of the similarity of transmissible venereal tumor samples collected independently in different parts of the world. Oligonucleotide primers flanking the LINE/c-MYC junction were used to amplify a 340-base-pair segment and nested primers amplified a 280-base-pair segment. A fifth oligonucleotide used as a probe contained the actual junction sequence. All of the tumors analyzed revealed the existence of the specific bands, which were absent in normal canine DNA samples. The amplified segments obtained from all of the tumors analyzed were identical in size and nucleotide sequence, suggesting transmission of the original rearranged cell itself, as opposed to independent events of LINE insertion in a "hot spot."

Animals↗
PubMed1991

EBV genome and immunoglobulin gene rearrangement in the differential diagnosis of nasopharyngeal carcinoma and lymphoma.

Head and neck tumors include nasopharyngeal carcinoma (NPC) and lymphoma. The differential diagnosis of these tumors is based on histology, immunocytochemical staining, and EBV serology. In rare cases it might be difficult to distinguish between NPC and lymphoma in HE section or biopsies. DNA hybridization with cloned EBV and human immunoglobulin gene fragments allows the detection of EBV-related sequences and immunoglobulin gene rearrangements. The presence of EBV genome supports the diagnosis of NPC or EBV related BL, while rearrangement of immunoglobulin genes points to B-cell lymphoma. The diagnosis in 11 patients suspected of head and neck tumors was carried out by hybridization of DNA extracted from the tumors and assayed with cloned EBV and IgHCJ DNA probes. One patient proved to have EBV-associated BL based on positive hybridization with EBV probes and immunoglobulin rearrangement, presenting a unique hybridization with cloned EBV DNA BamHI W fragment, with bands of 3.2 and 3.9 kb. BL was confirmed in this patient by demonstration of c-myc rearrangement. A second patient was negative in hybridization with EBV, and positive for immunoglobulin rearrangement, and therefore was diagnosed as having B-cell lymphoma. In seven patients NPC was confirmed by hybridization with EBV-DNA probes. In two patients, both NPC and B-cell lymphomas were excluded.

Adolescent↗
PubMed1991

Lack of bcr rearrangement in juvenile chronic myeloid leukemia.

Juvenile chronic myeloid leukemia (JCML) is an unusual subtype of children's leukemia, characterized by unique clinical presentation. Recent studies revealed several biological features, distinguishing from those observed in adult type chronic myeloid leukemia (ACML). The majority of ACML cases are characterized by the presence of an hybrid bcr-abl rearranged gene. In an effort to elucidate the molecular basis of this unusual leukemia we looked for bcr rearrangement in six JCML cases. No bcr rearrangement was identified in any of the analyzed samples. Together with previous studies from JCML cases, JCML has a different mechanism of leukomogenesis from ACML.

Blotting, Southern↗
PubMed1991

Lymphokine-activated killer (LAK) cells: interferon-gamma synergizes with interleukin-2 to induce LAK cytotoxicity in homogeneous leukemic preparations.

Lymphokine-activated killer (LAK) cells are generated by the incubation of lymphocytes with high levels of interleukin-2 (IL-2). We report here that interferon-gamma (IFN-gamma) acts synergistically with low levels of IL-2 to promote LAK differentiation in peripheral blood lymphocytes as well as in homogeneous T acute lymphocytic leukemic cells exhibiting LAK precursor reactivity. No augmentation of LAK response was observed with IFN-alpha-2, IFN-beta-1, and IFN-beta-2/IL-6. The synergism between IL-2 and IFN-gamma was expressed in the ability of activated lymphocytes to lyse natural killer resistant cell line targets and surgically removed melanoma cells. The augmented LAK response due to IFN-gamma does not reflect up-regulation of the high-affinity IL-2 receptors consisting both of alpha and beta subunits, since expression of the alpha (Tac) subunit on the responding leukemic cells was not increased by IFN-gamma. The observed IFN-gamma/IL-2 synergism in the induction of monoclonal LAK precursors suggests that a single precursor cell responds to both IFN-gamma and IL-2 and that different mechanisms underlie the basal IL-2-mediated LAK response and its enhancement by IFN-gamma.

Cytotoxicity, Immunologic↗
PubMed1991

Kaposi's sarcoma among AIDS patients: transmissible venereal tumour by cell engraftment?

The epidemiologic findings of Kaposi's sarcoma (KS) among patients with the acquired immunodeficiency syndrome (AIDS) suggest that human immunodeficiency virus (HIV) infection is insufficient for the development of KS. It was speculated that another sexually transmitted infection is responsible for the markedly increased incidence of KS among patients who acquired HIV infection through sexual intercourse. However, no such contributing infectious agent was consistently identified. The canine transmissible venereal tumour (TVT) is a malignant tumour that can be transplanted by viable cells across major histocompatibility complex (MHC) barriers. Recent findings suggest that all canine TVTs originated from the same tumour and were transferred from one animal to the other during sexual intercourse. It is suggested that, in analogy with the canine TVT model, the characteristics of KS epidemic among AIDS patients may be explained by transmission and engraftment of viable malignant cells during intercourse.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Bone marrow cell populations mimicking common acute lymphoblastic leukemia in infants with stage IV-S neuroblastoma.

Immunophenotyping of bone marrow mononuclear cells of 2 infants with stage IV-S neuroblastoma revealed the presence of many lymphoblasts and immature lymphocytes. Immunophenotyping showed that a high percentage of bone marrow cells were positive for the HLA-DR, CD19, CD20 and CD10 phenotype, similar to common acute lymphoblastic leukemia cells. Within 6 months of follow-up, without any treatment, complete regression of the tumors was observed. The coexistence of these two unusual populations will be discussed.

Bone Marrow↗
PubMed1990

Chromosomal aberrations suggestive of mutagen-related leukemia after 21 years of "therapeutic" radon exposure.

A 68-year-old woman with acute myelomonocytic leukemia, who was treated annually for 21 consecutive years by "therapeutic" low-dose radon gas radiation because of spondyloarthritis, is described. The karyotype of the malignant clone was 45,XX, -17, -18,del(5)(q15q33), +t(17;18)(q11.2q23). In 45% of the metaphases, the modal number was between hyperdiploid to near tetraploid. Double minute chromosomes were demonstrated in 60% of the cells. These chromosomal aberrations are suggestive of mutagen-related leukemia.

Aged↗
PubMed1990

[Treatment of acute myeloid leukemia in a special hematology unit].

Since 1984, 47 patients with untreated acute myeloid leukemia (AML) were hospitalized in a special hematology unit for aggressive chemotherapy. Complete remission was obtained in 68%, 15% died of complications of treatment (infections and bleeding) and 15% had refractory leukemia. The actuarial survival after 3 years for patients in remission was 43%. No patients with refractory leukemia lived more than 1 year. The actuarial remission at 3 years of 21 patients who received additional courses of aggressive chemotherapy (consolidation treatment) was 42%, as opposed to 11% in 11 patients who received maintenance treatment. The 47 patients received 108 courses of aggressive chemotherapy including 47 for induction of remission. During 86 courses (80%) the patients developed fever and in 33 blood cultures were positive; during 16 courses a fungal infection developed. The most common bacterial infection was by E. coli. During the first induction treatment 5 patients died of sepsis and 1 of cerebral hemorrhage. None died during consolidation therapy. During the year preceding the opening of the unit, 12 AML patients were treated on regular medical wards, and five (42%) achieved a complete remission, while 6 died of complications during the first course of induction chemotherapy. Our findings are in line with those of similar units, which indicates the importance of special nursing units for the treatment of acute leukemia.

Adolescent↗