Clonal chromosomal abnormalities in hemangiopericytoma

We report the cytogenetic findings in nine hemangiopericytomas studied after short-term culture. Clonal chromosome abnormalities were present in four cases. One case had a simple translocation (12;19)(q13;q13.3) as the sole abnormality whereas complex and multiple chromosomal abnormalities involving almost all chromosomes in the complement characterized tumors from the three other cases.     

Chromosome changes in bladder cancer: clinical and other correlations

The chromosome changes in bladder cancer are reviewed with particular emphasis on the application of recent advances in techniques for cytogenetic analyses of bladder cancer and the establishment of nonrandom (specific) karyotypic changes characterizing a significant number of bladder cancers. At present, these groups are characterized by one of the following cytogenetic changes: i(5p), +7, or -9. The results are discussed in relation to the significance of these changes and possible involvement of some oncogenes and other gene loci.     

Human adipose-derived adult stem cells produce osteoid in vivo

Adult subcutaneous fat tissue is an abundant source of multipotent cells. Previous studies from our laboratory have shown that, in vitro, adipose-derived adult stem (ADAS) cells express bone marker proteins including alkaline phosphatase, type I collagen, osteopontin, and osteocalcin and produce a mineralized matrix as shown by alizarin red staining. In the current study, the ADAS cell ability to form osteoid in vivo was determined. ADAS cells were isolated from liposuction waste of three individual donors and expanded in vitro before implantation. Equal numbers of cells (3 x 10(6)) were loaded onto either hydroxyapatite/tricalcium phosphate (HA-TCP) cubes or the collagen/HA-TCP composite matrix, Collagraft, and then implanted subcutaneously into SCID mice. After 6 weeks, implants were removed, fixed, and demineralized and sectioned for hematoxylin and eosin staining. Osteoid formation was observed in 80% of HA-TCP implants loaded with ADAS cells. Only 20% of Collagraft implants were positive for the presence of osteoid matrix. Whereas 100% of HA-TCP implants loaded with hFOB 1.19 cells formed osteoid, Collagraft loaded with hFOB 1.19 cells displayed a high degree of adipose tissue within the matrix. Immunostaining of serial sections for human nuclear antigen demonstrated that the osteoid contained human cells. Osteoid formation was not observed in control HA-TCP or Collagraft matrices implanted without cells. In summary, the data demonstrate the ability of ADAS cells to form osteoid matrix in vivo. Because of their abundance and accessibility, ADAS cells may prove to be a novel cell therapeutic for bone repair and regeneration.     

Age-dependent increase of peritoneal B-1b B cells in SCID mice

The impact of increasing age upon immunoglobulin production and B-lymphocyte generation in "leaky" severe combined immune-defective (SCID) mice was examined by enzyme-linked immunosorbent assay and flow cytometry. By 1 year of age, the mice had normal numbers of B cells in their peritoneal cavity, while their spleen had very few immunoglobulin M-positive (IgM+) cells. The majority of B cells expressed the CD11b marker characteristic of the B-1b subset. B-1a (CD5+) cells were present at a lower frequency and B-2 cells were absent. The frequency of mice producing detectable immunoglobulin increased with age, and isotype diversity within individual mice was variable. IgM production was most frequently observed followed by IgG3 and IgG2a, then IgG1, and finally IgA. The selective persistence of the B-1 B-cell subset in the peritoneal cavity of aging SCID mice is a natural model for the study of those genetic and environmental influences that determine lymphocyte longevity.     

Studies on thymocyte subpopulations in guinea pigs: in vivo differentiation of bromodeoxyuridine labelled cells, with special reference to rosette-forming ability

Cycling thymocytes were labelled by an intracardial injection of bromodeoxyuridine (BrdUrd) in a total of 32 guinea pigs and the incorporation into DNA studied in subpopulations of cells defined by buoyant density and rosette-forming ability. The labelling pattern was compared at different times after injection (0.5 h to 120 h). A marked shift of labelled cells from large, low density cells (population 1a) to small, high density cells (population 2) was observed. During the first 48 h, the ratio between labelling indices of cell populations 1a and 2 decreased from 10 to 0.5. The number of labelled cells forming rosettes with rabbit erythrocytes (RFC+) increased while the number of labelled non-rosetting cells (RFC-) decreased from 0.5 h to 48 h, probably representing transformation of RFC- to RFC+. Then, after a decreased labelling in all cell populations at 72 h, an increase in both RFC+ and RFC- populations occurred at 96 h. The labelling in RFC- cells at 96 h was nearly as high as immediately after labelling. This second labelling of RFC- cells could represent immigration of precursor cells, a wave of proliferation in initially labelled precursors, and/or the formation of mature cells from the initially labelled precursors. The results indicate that a great majority of proliferating cells differentiate into small, high density cells within 48 h and that rosetting ability is acquired in many cells during this period. A model of intrathymic differentiation which fits the observations is presented.     

Chromosome abnormalities in two benign adipose tumors

Two histologically benign adipose tumors were found to have clonal karyotypic changes. Del(4), del(6), and inv(13) were present in a fibrolipoma, and t(7;8) in a lipoblastoma. Additional studies are needed of the frequency and malignant potential of lipomas with cytogenetic abnormalities.     

Two 14q+ chromosomes in malignant lymphoma: crucial cytogenetic changes on 14q

We encountered a 36-year-old white male patient with poorly differentiated lymphocytic lymphoma, whose lymph node cells showed a clonal cytogenetic change involving chromosome #14, i.e., 47,XY, + 2,der(14),t(14;14)(14pter----14q32;14q24----14q32++ +). In addition to this change, cells with a translocation between chromosomes #2 and another #14 [t(2;14)(q21;q24)], as well as a missing chromosome #8 were found. We have reviewed the literature dealing with two or more changes affecting chromosome #14 and discussed the importance of the cytogenetic change at band 14q32 in malignant lymphoma.     

Chromosomes and causation of human cancer and leukemia. LIV. Near-tetraploidy in acute leukemia

Near-tetraploid cell populations were observed in a case of T-cell acute lymphoblastic leukemia (T-ALL) and in one of acute myeloblastic leukemia (AML). In the ALL case, hyperdiploid chromosomal changes, characterized by an isochromosome 17q [i(17q)], as well as other changes, were seen at the onset of the disease. At the first relapse, hypertetraploid cells appeared in about 10% of the mitoses in the bone marrow (BM), and by the second and third relapses, the hypertetraploidy was present in more than 90% of the mitoses in the BM. Even though karyotypic instability was evident, all abnormal karyotypes contained one or two i(17q) at every sampling. In spite of karyotypic instability at each relapse, karyotypic evolution was observed whenever relapse occurred. A normal female karyotype was confirmed in the BM of each period. Immunologic examinations performed at each sampling revealed no recognizable changes before and after the appearance of tetraploidy. In the AML case, which was classified as FAB M2, cytogenetic examination was performed at diagnosis and relapse. In both, hypotetraploid cells were observed in over 60% of the BM cells; the modal chromosome number was 90. Banding analysis was successful at relapse, and a pseudodiploid clone characterized by t(8;21) and a hypotetraploid clone with two t(8;21) and a loss of two Y chromosomes were observed in the same BM sample. A normal male karyotype was also observed in BM cells. In both cases, giant and bizarre blasts were seen in the BM. A close correlation between near-tetraploid mitoses and giant and bizarre blast cells in BM smears of the same samples was observed. Previously published tetraploid acute leukemia cases analyzed with banding methods were accumulated and compared with our two cases.