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Biomedical subjects

J Tanzer

Publications and source records attributed to J Tanzer.

At least 73 records · Page 4Linked to original sources
PubMed1988

Karyotype evolution in the bone marrow of a patient with Fanconi anemia: breakpoints in clonal anomalies of this disease.

A 21-year-old Fanconi anemia patient developed refractory anemia. Laboratory studies revealed a transitory increased platelet count and a typical del(5q). Bone marrow karyotyping showed a -6, +der(6)t(1;6)(q12;p25) rearrangement and, two years later, a mosaic -6, +der(6),t(1:6)(q12;p25)/-2, +der 2), t(1;2)(q12;q37) constitution. The chromosome mechanism operating in this patient is discussed.

Adult↗
PubMed1988

Characterization of prothymocytes with cloning capacity in human bone marrow.

The identity of human bone marrow (BM)-derived T cell precursors with colony forming capacity has led to controversy because of contamination with mature clonogenic T cells. We achieved 2 Log elimination of mature T cells from BM using a cocktail of monoclonal antibodies: CD2, CD3, CD4, CD6, and CD8 followed by two successive baby rabbit C' treatment. T cell depleted BM can generate colonies of CD2+, CD3+, Ti+, mostly CD4+, in the presence of PHA, rIL2, and a prothymocyte differentiating activity derived from phytohemagglutinin (PHA) induced mononuclear cells. These precursors could be enriched three- to sixfold by percoll gradient centrifugation and then significantly bypass the number of contaminant mature T cells as shown by limiting dilution analysis. Colony generation by marrow precursors was inhibited by the addition of autologous T cells. This inhibition was mostly caused by the T8+ subset. CFU-TL growth was dramatically inhibited by eliminating CD7+ cells suggesting their positivity for this surface marker. These precursors needed major histocompatibility complex (MHC) II-positive cells for optimal growth but lack DR themselves.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

[Acute leukemia with translocation (8;16)].

Three cases of M5 acute leukemia, 1 with a t(8;16)(p11;p13), 2 with variant translocations, both with a breakpoint at band 8p11, t(6;8)(q27;p11) and t(8;19)(p11;q13) are reported and 12 other published cases reviewed. This is a rare new entity, of variable but rather poor prognosis, seen from birth to 75 years of age, with several cases in infants. Leukemic cells, which often show conspicuous phagocytic activity on bone marrow smears, bear both monocytic and granulocytic markers in at least some cases. The best therapeutic regimen is not well-defined. The molecular basis of the disorder remains to be elucidated.

Adult↗
PubMed1988

Malignant histiocytosis: a specific t(2;5)(p23;q35) translocation? Review of the literature.

In this paper, the investigators report a well documented case of malignant histiocytosis (MH) with a t(2;5)(p23;q35) translocation. A breakpoint in 5q35 appears to be specific, either for the disease or for a subclass of the disease. Additional cases of MH with cytogenetics are needed. This will help to determine if one class of MH or several subclasses can be defined by cytogenetic anomaly(ies).

Adolescent↗
PubMed1987

Hermansky-Pudlak platelets: further studies on release reaction and protein phosphorylations.

Platelets from a patient with the Hermansky-Pudlak syndrome were studied. These platelets had decreased amounts of serotonin and adenine nucleotides, and a decreased number of mepacrine-labeled dense bodies. beta-Thromboglobulin and acid hydrolases contained in alpha-granules and lysosomes respectively were present in normal amount. Platelets in platelet-rich plasma did not respond to collagen, but arachidonic acid and ionophore A 23187 induced normal aggregation and normal thromboxane (TX) synthesis. Alpha-granule release was found impaired and remained subnormal even with high doses of inducers. In response to thrombin aggregation, release and TX synthesis of isolated metrizamide gradient platelets were found at lower than normal levels. Phosphorylation of P20 and P43 proteins was normal. Only a combination of ADP plus thrombin could restore a normal aggregation, with normal alpha-granule and lysosome release and normal TX synthesis. These results indicated that in the absence of dense bodies: the release of other granules is impaired; the TX synthesis is delayed except when induced by arachidonic acid and A 23187 ionophore; the absence of dense bodies could be compensated for by the addition of ADP which restores the impaired release reaction and TX formation; and P20 and P43 polypeptides were phosphorylated as rapidly as those in normal platelets.

Adenine Nucleotides↗
PubMed1987

Down syndrome with duplication of a region of chromosome 21 containing the CuZn superoxide dismutase gene without detectable karyotypic abnormality.

We report the case of an 18-month-old boy with many typical Down syndrome features but a normal cytogenetic analysis. High-resolution banding techniques on lymphocytes and fibroblasts of the propositus and his parents did not show any detectable abnormality including that of trisomy 21 mosaicism. However, CuZn superoxide dismutase (CuZn SOD) in the patient's red cells was increased as in trisomy 21. DNA analysis (Southern blots) using a human CuZn SOD probe showed that the genotype of the propositus contained three CuZn SOD genes. In situ hybridization on metaphase chromosomes with the same probe confirmed the gene location in a segment enclosing the distal part of 21q21 and 21q22.1. There was no significant labeling on other chromosomes of the patient. These results indicate that the Down syndrome phenotype of this patient is due to microduplication of a chromosome 21 fragment containing the CuZn SOD gene.

Chromosome Mapping↗
PubMed1987

[Rearrangement of the short arm of chromosome 12 in chronic myelomonocytic leukemias].

A rearrangement of the short arm of chromosome #12 with a breakpoint at band 12 was found in 4 out of 15 patients with CMML: two deletions, one simple translocation (9;12)(p21;p12) and one complex t(11;12;13)(p11;p12;q21). Their haematological and clinical characteristics were investigated together with those of 5 other similar published cases. Although this alteration is not very frequent in this myelodysplastic syndrome, and is also found in various other malignant blood disorders, it is clearly a non-random phenomenon, the consequences of which are discussed.

Chromosome Aberrations↗
PubMed1987

Enrichment of human marrow T-cell precursors by complement-dependent cytotoxicity with monoclonal antibodies and Percoll Gradient centrifugation.

Attempts to enrich and characterize human marrow T-cell precursors have been performed using discontinuous Percoll gradient centrifugation, phenotypic analysis of cells with monoclonal antibodies (Mabs), and T-cell colony-forming capacity. Marrow cells were extensively depleted of T cells and separated into seven fractions. The depletion was performed with the following Mabs: CD6 (MBG6 or RFT12) + CD8 (RFT8), CD2 (D66) + CD8 (RFT8), and CD6 (RFT12) + CD8 (RFT8) + CD7 (RFT2). A peak of cells with the capacity to differentiate into mature CD2+CD4+ T-cell agar colonies (TL-CFU) was obtained in a fraction with a density 1.063 less than d less than 1.069 g/ml. This peak was associated with the presence of cells expressing RFB1 and OKT10, two markers shared by hemopoietic precursors. Cells in this fraction were negative for CD3, CD4, CD1, CD8, and CD2 antigens. Their treatment by complement-dependent cytotoxicity with the CD7 Mab resulted in a loss of T-cell colony-forming capacity together with a reduction of T10-, RFB1-, and My10-positive cells.

Antibodies, Monoclonal↗
PubMed1986

Aberrant breakpoints in chronic myelogenous leukaemia; oncogenes and fragile sites.

Three hundred and twenty-five aberrant breakpoints in chronic myelogenous leukaemia (CML) with Philadelphia chromosome variant were reviewed. Eight chromosomal bands (3p21, 6p21, 7p22, 11q13, 12p13, 17p13, 17q21, and 17q25) were found to be highly involved. Apart from 17q25, all these bands correspond to oncogenes sites and/or sites involved as primary breakpoints in cancer.

Chromosome Banding↗
PubMed1986

Endogenous production of prothymocyte differentiating activity by phytohemagglutinin-stimulated T-cell-depleted human marrow.

The PHA responsiveness of marrow T-cell precursors remains a matter of controversy. We have investigated the capacity of human marrow to proliferate under phytohemagglutinin (PHA) stimulation following extensive removal of mature T cells by complement-dependent cytotoxicity with MBG6 and RFT8 monoclonal antibodies. PHA-induced thymidine uptake by marrow cells occurred with a peak on Days 6-8 of incubation instead of Day 3 for PBL. This peak was observed 48 hr earlier in the presence of PHA-stimulated T-depleted marrow cell supernatants. These supernatants can also promote the growth of mature T-cell colonies from MBG6-, RFT8-, T11-, T3- marrow. However, full colony development requires exogenous interleukin 2 (IL-2). IL-2 could be detected in marrow supernatants but only at very low levels and beyond Days 3 and 4. In contrast Days 1-6 marrow supernatants were equally effective in promoting MBG6-RFT8- marrow cell responsiveness to PHA. We conclude that marrow T-cell precursors are not PHA responsive and that PHA induces the production by marrow non-T cells of a prothymocyte-differentiating activity (PTDA); PTDA can differentiate marrow T-cell progenitors into PHA-responsive T cells; following activation by PHA, these cells undergo limited proliferation induced by IL-2 endogenously released from de novo differentiated T cells. It is suggested that this mechanism may account for extrathymic differentiation of the T-cell lineage in heavily irradiated marrow transplantation recipients.

Antibodies, Monoclonal↗
PubMed1986

In vitro effects of sodium diethyldithiocarbamate (Imuthiol) on human T lymphocytes.

The effect of purified diethyldithiocarbamate, DTC (Imuthiol) on human T-cell dependent functions has been investigated. The mitogenic response of PHA-stimulated peripheral blood lymphocytes (PBL) was significantly enhanced by Imuthiol at low drug concentration (10(-7) mg/ml). The same dose of Imuthiol also stimulated IL2 production by human PBL. This enhancement depended on the presence of adherent cells. These results could, in part, explained the immunostimulant activity of Imuthiol.

Ditiocarb↗