Marmoset CYP3A21, a model for human CYP3A4: protein expression and functional characterization of the promoter.

Due to its small size and the relative evolutionary proximity, the marmoset has been proposed as a model for studies of human drug interactions and metabolism. The current study investigated the expression and regulation of marmoset CYP3A using mass spectrometry and reporter gene techniques. Expression levels of hepatic marmoset CYP3A protein range from 51 to 123 pmol mg-1 total protein (mean 85.2 pmol mg-1, n = 10) and CYP3A21 is the dominant hepatic CYP3A protein in marmosets. The sequence similarity between human CYP3A4 and CYP3A21 across the first 7.5 kb of the cloned CYP3A21 promoter is 88% within the xenobiotic-responsive enhancer module (XREM) and the proximal promoter. Both regulatory modules confer transcriptional activation of CYP3A21-luciferase reporter gene constructs cotransfected with hPXR in intestinal LS174T cells. The pronounced response to rifampin and the moderate response to dexamethasone were similar to those observed with CYP3A4. Taken collectively, these data establish substantial similarities in expression and gene regulation between marmoset CYP3A21 and human CYP3A4. CYP3A21 may be an equivalent of CYP3A4 in New World monkeys, consistent with the phylogenetic relationship between these genes. The marmoset, therefore, appears to be a suitable in vivo model to study CYP3A4 function and regulation.

Successful therapy of convoluted T-lymphoblastic lymphoma in the adult.

Fifteen adult patients with biopsy-proven convoluted T-lymphoblastic lymphoma were treated with an aggressive regimen, modified from the LSA2-L2 protocol used for childhood lymphoma. The treatment schema consisted of induction phase, including cyclophosphamide, vincristine, prednisone, adriamycin, and 2000 rads to mediastinum, as well as intrathecal methotrexate. Consolidation phase included cytosine arabinoside, 6-thioguanine, L-asparaginase, and CCNU, along with cranial irradiation and further intrathecal methotrexate. Maintenance consisted of cyclical chemotherapy and intrathecal methotrexate, continuing for a total of 3 yr. Median age in the group was 25 yr (range 16-73). There were 8 males and 7 females. At diagnosis, 9 patients had mediastinal involvement, and 9 had bone marrow involvement. Five of these demonstrated malignant cells in the peripheral blood. Complete clinical response was attained in 11 patients. Three patients achieved partial response. Four complete responders have relapsed, 1 in the central nervous system at 6 mo. and 1 in nodal sites at 3 mo, 1 in multiple sites at 24 mo. and 1 in bone marrow at 42 mo while off all chemotherapy for 6 mos. At this time, median survival of all patients is 28.3 mo. and median relapse-free survival is 21 mo. The median survival for complete responders in excess of 71 mo. while the median relapse-free survival for this group is 41 mo.

Immunoblastic sarcoma of T-cell versus B-cell origin: I. Clinical features.

Within the Lukes-Collins classification system of malignant lymphoma, a tumor of large transformed lymphocytes, termed immunoblastic sarcoma (IBS), is described. This morphological type would have been included within the "histiocytic" category of Rappaport. Immunoblastic sarcoma may be of B-lymphocytic or T-lymphocytic origin. Since differences or similarities of these two variants have not yet been described, we reviewed the case histories of 35 such patients, all of whom had immunologic marker studies performed. Nineteen patients had T-cell IBS (T-IBS), whereas 16 had B-cell IBS (B-IBS). Median age for both groups was approximately 50 yr. A history of prior immune disorder was found in 31% of B-IBS and 16% of T-IBS cases. Prior lymphoproliferative malignancy was noted in 21% of T-IBS and 13% of B-IBS patients. All T-IBS patients first presented because of lymphadenopathy, whereas 56% of B-IBS cases initially presented because of extranodal disease. Systemic "B" symptoms were common in both. Similarly, most patients had widespread disease (stage III or IV) at diagnosis. Clinically suspected hepatic (p = 0.05) and retroperitoneal node (p = 0.01) involvement were more often found in T-IBS. Forty-one percent of T-IBS patients demonstrated polyclonal hypergammaglobulinemia, a finding seen in no B-IBS patient (p = 0.02). Although not statistically significant because of small numbers of patients, data on therapy and survival suggest that IBS of B-cell type may be successfully treated with aggressive, multiagent chemotherapy, while alternative approaches appear warranted in T-cell disease.