The expression of the natural killer (NK) cell marker CD56 has been reported to occur in NK cell lymphomas/leukemias and a small group of peripheral T-cell lymphomas but has not been studied extensively in primary intestinal non-B-cell lymphomas. Normal human jejunal intraepithelial lymphocytes (IELs) are mainly T-cell receptor (TCR)-alphabeta+CD3+CD8+CD5low and include an approximately 15% fraction of CD56+ cells that could be the cells of origin for CD56+ intestinal T-cell lymphoma (ITL). To test this hypothesis, 70 cases diagnosed as ITL were immunophenotyped, and 15 CD56+ cases (21%) were identified. The majority of the CD56+ lymphomas was of monomorphic small to medium-sized histology, shared the common phenotype betaF1+/-CD3epsilon/cyt+CD8+CD4-CD5-CD57-TIA-1+ and had clonally rearranged TCR gamma-chain genes. In contrast, the CD56- lymphomas were mainly composed of pleomorphic medium and large cells or had a morphology most consistent with anaplastic large-cell lymphoma and were mostly CD8-. These findings suggest that the majority of CD56+ intestinal lymphomas are morphologically and phenotypically distinct T-cell lymphomas most likely derived from activated cytotoxic CD56+CD8+ IELs. Some overlapping histological and clinical features between CD56+ and CD56- ITLs indicate that the former belong to the clinicopathological entity of ITL. The consistent expression of cytotoxic-granule-associated proteins introduces ITL (both CD56+ and CD56-) into the growing family of usually aggressive extranodal lymphomas of cytotoxic T-cell and NK-cell derivation. In contrast to putative NK-cell lymphoma of the sinonasal region, intestinal NK-cell lymphoma seems to be very rare.

Mistletoe (Viscum album L.) contains the triterpene acids oleanolic acid (OA) and betulinic acid (BA), which were found to have anti-tumour properties. In this study, the solubilities of OA and BA were studied in water (up to 0.02 microg/mL in each case) and in alkaline solutions of 10 mM trisodium phosphate (pH 11.5; OA: 77.2 microg/mL; BA: 40.1 microg/mL). Furthermore, triterpene acids were quantified in aqueous mistletoe extracts (pH 7.3; drug to extract ratio 1:25). OA (1.1 microg/mL) and BA (0.9 microg/mL) were extracted with a yield of less than 5%. Preparing plant extracts with basic pH values resulted in a triterpene acid content of 9.3 microg/mL OA and 5.2 microg/mL BA (pH 12.1), reaching neither the solubility limits nor a complete extraction of the plant material. The triterpene acid content of neutral plant extracts above the solubility limit could be due to interactions with biocolloids. Interaction studies were performed by gel permeation chromatography. Different mechanisms of the dissolution at pH 7.3 and pH 10.2 are discussed.

The prognostic value of the detection of peripheral blood (PB) and/or bone marrow (BM) involvement by polymerase chain reaction (PCR) amplification of rearranged immunoglobulin heavy chain (IgH) and immunoglobulin kappa light chain (Igj) genes was evaluated in 155 patients with diffuse large B-cell lymphomas (DLBCL). Immunoglobulin gene rearrangements (IgR) were detected in 35/155 (23%) patients. The presence of IgR in PB/BM was related to clinical stage (CS I-III vs CS IV; Po0.001), histopathological detection of BM involvement (Po0.001), and the International Prognostic Index (Po0.001). IgR-positive cases had a significantly lower complete remission (CR) rate (18/35, 51%) than IgR-negative patients (85/120, 71%; P ¼ 0.042), and a significantly poorer overall survival (OAS) at 5 years (25 vs 66%; Po0.001). There was a significant difference in the estimated OAS at 5 years between patients with negative BM histology and negative PCR results (66%), patients with negative BM histology but positive IgR (37%), and patients with positive BM histology (12%). Our results indicate that molecular methods improve the accuracy of staging in patients with DLBCL and define a group of patients with normal bone marrow histology who have a significantly poorer OAS due to molecular detection of PB/BM involvement.

The Escherichia coli chemoreceptors for serine (Tsr) and aspartate (Tar) and several bacterial class III adenylyl cyclases (ACs) share a common molecular architecture; that is, a membrane anchor that is linked via a cytoplasmic HAMP domain to a C-terminal signal output unit. Functionality of both proteins requires homodimerization. The chemotaxis receptors are well characterized, whereas the typical hexahelical membrane anchor (6TM) of class III ACs, suggested to operate as a channel or transporter, has no known function beyond a membrane anchor. We joined the intramolecular networks of Tsr or Tar and two bacterial ACs, Rv3645 from Mycobacterium tuberculosis and CyaG from Arthrospira platensis, across their signal transmission sites, connecting the chemotaxis receptors via different HAMP domains to the catalytic AC domains. AC activity in the chimeras was inhibited by micromolar concentrations of L-serine or L-aspartate in vitro and in vivo. Single point mutations known to abolish ligand binding in Tar (R69E or T154I) or Tsr (R69E or T156K) abrogated AC regulation. Co-expression of mutant pairs, which functionally complement each other, restored regulation in vitro and in vivo. Taken together, these studies demonstrate chemotaxis receptor-mediated regulation of chimeric bacterial ACs and connect chemical sensing and AC regulation.The canonical chemotaxis receptors Tsr for serine and Tar for aspartate of Escherichia coli have been studied extensively as model signaling systems that regulate bacterial swimming behavior (1-5). Ligand binding to the periplasmic domain of the receptor initiates a biochemically defined cascade of events that finally results in reversal of the flagellar beat (4, 6). The chemotaxis receptors are tripartite proteins with a periplasmic receptor anchored in the cytoplasmic membrane by two transmembrane spans followed by a HAMP domain (histidine kinases, adenylyl cyclases, methyl-accepting proteins of chemotaxis, and protein phosphatases (7)) which adjoins the second transmembrane helix and serves as a signal converter followed by an output domain as C terminus (3). Homodimerization of Tsr or Tar chemoreceptors is required for function, and the ligands bind in the periplasmic interface between the subunits (8 -11). The ubiquitous HAMP domains are signal converters of 55-60 amino acids with a homodimeric fourhelical parallel coiled-coil conformation (12). In the chemotaxis receptors the HAMP domain operates as a C-terminal histidine kinase control unit that has no known intrinsic enzymatic activity. As this molecular architecture is predominant in the 30 known sensor kinases of E. coli, a variety of chimeric sensor proteins has been generated successfully in the past that consist of modules derived from different E. coli sensors (see examples in Refs. 13-15).A similar tripartite domain architecture as in chemotaxis receptors exists in several class III AC 2 isoforms in eubacteria. Class III AC isoforms outnumber all others, are prevalent in bacteria, and include all eukaryotic ACs (16 -17). ...

Although mast cells are hematopoietic cells, little is known about the origin of their precursors in vivo. In this study, the origin (donor v recipient genotype) of human mast cells (MCs) was analyzed in a patient who underwent allogeneic bone marrow transplantation (BMT). The patient presented with secondary acute myeloid leukemia (French-American- British classification, M2) arising from refractory anemia with excess of blast cells and bone marrow (BM) mastocytosis. Transplantation was performed in chemotherapy-induced complete remission. On days 88, 126, 198, and 494 after BMT, mast cells were enriched to homogeneity from bone marrow mononuclear cells (BM MNCs) by cell sorting for CD117+/CD34- cells. Purified mast cell populations were CD117(c-kit)+ (> 95%), CD34- (< 1%), CD3- (< 1%), CD14- (< 1%), and virtually free of contaminating cells as assessed by Giemsa staining. The genotype of MCs was analyzed after amplification by polymerase chain reaction (PCR) of a variable number tandem repeat (VNTR) region within intron 40 of the von Willebrand factor (vWF) gene. Unexpectedly, on days 88 and 126 after BMT, sorted MCs displayed recipient genotype as shown by vWF.VNTR-PCR. However, on days 198 and 494, PCR analysis showed a switch to donor genotype in isolated mast cells. Peripheral blood (PB) and BM MNC as well as highly enriched (sorted) CD3+ T cells (PB, BM), CD4+ helper T cells (PB), CD8+ T cells (PB), CD19+ B cells (PB), CD14+ monocytes (PB, BM), and CD34+ precursor cells (BM) showed donor genotype throughout the observation period. Together, these results provide evidence that human MCs developed in vivo from transplanted hematopoietic stem cells. Engraftment and in vivo differentiation of MCs from early hematopoietic progenitor cells may be a prolonged process.