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Biomedical subjects

S N Jani Sait

Publications and source records attributed to S N Jani Sait.

7 recordsLinked to original sources

A t(11;12) 11q23 leukemic breakpoint that disrupts the MLL gene.

Translocations involving 11q23 have been shown to be a consistent finding in human hematopoietic malignancies and in some constitutional abnormalities. The identification of a gene, MLL (myeloid/lymphoid or mixed-lineage leukemia), that spans the breakpoints in four different recurrent 11q23 translocations was recently reported. We describe a rare (11;12)(q23;p13) translocation, observed in leukemic cells from a patient with acute lymphoblastic leukemia, which also disrupts this gene.

Blotting, Southern↗

A chromosome 11 YAC library.

A targeted yeast artificial chromosome (YAC) library for chromosome 11 has been constructed from the J1 cell line that carries a single human chromosome 11 within a hamster DNA background. Interspecies chimeric clones generated during construction of the library were detected during the screening process and eliminated from the library. Contig assembly becomes much less difficult using such a library as the complexity is decreased and the ends of the clone inserts can be rescued for walking to neighboring clones. The library contains > 1824 clones with an average insert length of 337 kb. This represents a fourfold coverage of chromosome 11 or a > 95% chance of recovering a unique single-copy sequence from the library. Two hundred YAC clones were localized by fluorescence in situ hybridization and found to be randomly distributed along the chromosome. The library has been screened with probes for the chromosome 11 markers HBB, GLUR4, H19, and D11S193. Corresponding YAC clones have been isolated for each locus. This analysis has indicated that the library is unbiased, that cognate YAC clones can be recovered with chromosome 11 markers, and that extensive contig assembly should be feasible.

Animals↗

Cytogenetic study of maturing granulocytes in bone marrow of patients with acute myelogenous leukemia.

To determine the cytogenetic origin of maturing granulocytes in the bone marrow of patients with acute myelogenous leukemia, bone marrow cells were studied using a modified cytogenetic technique, which does not disrupt the cell membrane, in conjunction with periodic acid-Schiff (PAS) staining. In four cases successfully studied, myeloblasts were PAS-negative and granulocytes were PAS-positive. In three cases successfully studied following 0-2 days of culture, metaphase spreads with abnormal karyotypes characteristic of the patients' leukemic clones were seen in five of five, six of nine, and four of four PAS-positive cells successfully studied. These patients' bone marrows were AN, AA, and AA, respectively, by standard cytogenetic study. Therefore, the cytogenetic status of PAS-positive cells did not necessarily correlate with presence or absence of normal metaphases determined by standard cytogenetic study. Bone marrow cells which underwent full and partial granulocytic maturation in suspension culture were studied following 2 weeks of culture. Abnormal karyotypes were seen in five of five and two of two metaphases in PAS-positive cells successfully studied in two patients. Therefore, we have demonstrated that when acute myelogenous leukemia cells undergo myeloid maturation in culture, the mature cells may be definitely proven to derive from leukemic progenitors rather than from normal stem cells.

Adult↗

Tetrasomy of chromosome 8: an interesting and rare cytogenetic phenomenon in acute nonlymphocytic leukemia.

Trisomy of chromosome #8 is a change commonly associated with acute nonlymphocytic leukemia (ANLL). However, tetrasomy of chromosome #8 in ANLL as a single chromosome change without accompanying abnormalities is extremely rare and, to the best of our knowledge, has not been reported to date. We present here a case of acute monocytic leukemia (AMoL, FAB M5b) with four copies of chromosome #8.

Acute Disease↗

Continued cell cycling ability of HL-60 cells following 3HaraC incorporation: a combination of "double-labeling" and sister chromatid analysis.

This study was designed to determine if HL-60 cells could undergo one or more cycles of DNA synthesis despite containing 3H-cytosine arabinoside (3HaraC) in their genome. HL-60 cells were incubated with 3HaraC for 2 hours, washed and maintained in a medium containing bromodeoxyuridine (BrdU). At fixed time points, cells were arrested in metaphase and prepared for chromosomal analysis. Treatment of the sample by an immunofluorescent monoclonal anti-BrdU antibody allowed us to determine the differential fluorescent pattern of sister chromatids in metaphase cells that had undergone two or more rounds of DNA synthesis in the presence of BrdU. Processing the samples by autoradiography demonstrated the presence of black grains (3HaraC) overlying the chromosomes. Thus, we were able to examine each metaphase for the presence of 3HaraC as well as the number of cycles it had completed in the presence of BrdU. We showed that despite the presence of 3HaraC in their DNA, some HL-60 cells were able to undergo two or more complete rounds of DNA replication.

Autoradiography↗

t(Y;18) in acute myeloblastic leukemia FAB type M2.

Changes affecting the Y chromosome in neoplasia have been documented. However, this usually occurs as a loss of the Y chromosome in the affected cells accompanied by or preceding other karyotypic changes. Involvement of the Y chromosome in a translocation is extremely rare, there being only 14 cases reported in the literature. Presented here is a case of t(Y;18) in acute myeloblastic leukemia type M2 (FAB).

Adult↗