Clinical and immunopathological significance of chimerism in bone marrow and organ transplantations

Chimerism is an exceptional immunogenetic state, characterized by the survival and collaboration of cell populations originated from two different individuals. The prerequisites to induce chimerism are immunosuppression, myeloablation or severe immunodeficiency of the recipients on one side and donor originated immuno-hematopoietic cells in the graft on the other. Special immunogenetic conditions to establish chimerism are combined with bone marrow transplantation, transfusion and various kinds of solid organ grafting. There are various methods to detect the type of chimera state depending on the immunogenetic differences between the donor and recipient. The chimera state seems to be one of the leading factors to influence the course of the post-transplant period, the frequency and severity of graft-versus-host disease (GVHD), and the rate of relapse. However, the most important contribution of the chimeric state is the development of graft versus leukemia (GVL) effect. A new conditioning protocol (DBM/Ara-C/Cy) for allogeneic BMT in CML patients and its consequence on chimera state and GVL effect is demonstrated.     

Classification of cDNA array genes that have a highly significant discriminative power due to their unique distribution in four brain regions

Novel statistical methods were used to distinguish functionally distinct brain regions using their cDNA array gene expression profiles, and it was found that one of four specific factors is often associated with the most regionally discriminative genes. The gene expression profiles for the substantia nigra (SN), striatum (STR), parietal cortex (PC), and posterolateral cortical amygdaloid nucleus (PLCo) brain regions were determined from each brain region. An F-test identified 339 genes of the 1185 array genes as having a P < or = 0.01 and applied a gene ranking and selection method based on Soft Independent Modeling of Class Analogy (SIMCA) to obtain 59 of the most discriminative genes. Their discriminative power was validated in three steps. The most convincing step showed their ability to correctly predict the brain regional classifications for 18 "test" gene expression sets obtained from the four regions. A two-way Hierarchical Cluster Analysis organized the 59 genes in six clusters according to their expression differences in the brain regions. Expression patterns in the SN and STR regions greatly differed from each other and the PC and PLCo. The closer similarity in the gene expression patterns of the PC and PLCo was probably due to their functional similarity. The important factors in determining differences in the regional gene expression profiles in six clusters were (1) regional myelin/oligodendrocyte levels, (2) resident neuron types, (3) neurotransmitter innervation profiles, and (4) Ca++-dependent signaling and second messenger systems.     

The somatostatin analogue peptide TT-232 induces apoptosis and chromosome breakage in cultured human lymphocytes

Somatostatin receptors are supposed to be important in the regulation of apoptosis. In this study, we measured apoptosis occurring spontaneously, or induced by the synthetic somatostatin analogue, the peptide TT-232. We examined isolated human peripheral blood lymphocytes (PBL) from 32 nurses exposed bedside to cytostatic drugs, 12 chronic lymphoid leukaemia (CLL) patients prior to treatment, and 19 unexposed, healthy donors without anamnestic occupational exposure to genotoxic agents. Cells were stimulated by phytohaemagglutinin-P (PHA) and cultured for 69 h with or without 15 microg/ml TT-232, respectively. Cell kinetic parameters and apoptosis were determined by flow cytometry after staining with FITC-labeled anti-BrdU and propidium iodide (PI) and the results on spontaneous and peptide-induced apoptosis were compared with the obtained chromosome aberration frequencies (CA). The peptide TT-232 unexpectedly induced chromosome breakage in addition to apoptosis. The mean spontaneous apoptotic fractions were 6.65+/-0.89%, 6.46+/-0. 53%, and 3.07+/-0.57%, and the mean CA yields in the samples without TT-232 were 1.74+/-0.46%, 2.44+/-0.40%, and 4.50+/-1.05%, for healthy subjects, nurses, and CLL patients, respectively. A total of 15 microg/ml TT-232 treatment in healthy subjects increased the mean CA frequency (10.38+/-1.57%), as well as the apoptotic cell fraction (2.63+/-0.45 times higher than the corresponding untreated sample). In TT-232-treated PBLs of nurses, CA remained unchanged and the mean apoptotic cell fraction showed only a slight increase (1.24+/-0.11 times higher than the untreated). Among CLL patients, TT-232 treatment significantly increased both CA (up to 17.83+/-4.04%) and the ratio of apoptotic cells (21.78+/-11.00 times higher than the untreated). These results demonstrated significant differences in apoptosis sensitivity in controls, nurses and CLL donors, after 15 microg/ml TT-232 treatment. Data also indicate that the induced CA yields in CLL donors with high CA are in correlation with TT-232-induced apoptosis.     

Polyethyleneglycol-Based Resins as Solid Supports for the Synthesis of Difficult or Long Peptides

An evaluation of the polyethyleneglycol-based ChemMatrix^? resin as solid support for the synthesis of challenging peptide sequences is presented. Comparison with conventional polystyrene and polyethyleneglycol-polystyrene resins in several instances of typically difficult solid phase syntheses shows a consistently better performance of the ChemMatrix^? resin in terms of end product purity. Representative test sequences include a 15-residue antibiotic, a gp41 ectodomain hybrid sequence, a calcipressin fragment with an N-terminal Arg₁₁ extension, and two chemokines of 69- and 64-amino acid residues. Interestingly, a difference in only five amino-acids between the two chemokine sequences had a remarkable impact on synthetic results, which in the case of the 69-residue peptide required additional refinements (β-sheet-breaking pseudoproline dipeptides) for success. This paper is dedicated to the memory of Bruce Merrifield, a dear teacher, mentor and friend.     

The phylogenetic relationships among some Randia (Rubiaceae) taxa

Phylogenetic relationships among some Randia (Rubiaceae, Gardenieae) taxa were estimated based on sequence variation in the nuclear ribosomal internal transcribed spacers (ITS) and rps 16 intron (cpDNA). During the investigation of rpsl6 intron of 9 studied Central American Randia species, two well supported subclades were separated. Analysis of ITS data of 16 Randia species shows 3 major clades. A group of mainly lowland, South American Randia species is moderate supported (75%). Species from Mexico form a strongly supported (97%) clade, but the Central American and Mexican Randia species are low supported (58%). However the last two groups are well supported together (95%). The molecular delimination is well in line with the size of leaves combined with the texture of exocarp.     

Facile synthesis of 11-carboxamido-androst-4,9(11)-dienes via palladium-catalyzed aminocarbonylation

11-Carboxamido-androst-4,9(11)-dienes were synthesized from the corresponding 11-iodo-androst-4,9(11)-diene derivative in palladium-catalyzed aminocarbonylation reaction under mild reaction conditions. The synthesis of the iodo-alkene substrate is based on the transformation of the 11-keto derivative to hydrazone, which was treated with iodine in the presence of a base (1,1,3,3-tetramethyl guanidine). The 11-carboxamides were synthesized in moderate to high isolated yields by using simple alkyl/arylamines or amino acid methylesters as N-nucleophiles. The highly active palladium catalysts enable the homogeneous catalytic functionalization at one of the most hindered position (C-11) of the steroidal skeleton.     

Transposition and target specificity of the typical IS30 family element IS1655 from Neisseria meningitidis

We have analysed the transposition and target selection strategy of IS1655, a typical IS30 family member resident in Neisseria meningitidis. We have redefined IS1655 as a 1080 bp long element with 25 bp imperfect inverted repeats (IRs), which generates a 3 bp target duplication and have shown that it transposes using an intermediate with abutted IRs separated by 2 bp. IS1655 exhibits bipartite target specificity inserting preferentially either next to sequences similar to its IRs or into an unrelated but well defined sequence. IR-targeting leads to the formation of a new junction in which the targeted IR and one of the donor IRs are separated by 2 bp. The non-IR targets were characterized as an imperfect 19 bp palindrome in which the central five positions show slight GC excess and the distal region is AT-rich. Artificial targets designed according to the consensus were recognized by the element as hot spots for insertion. The organization of IS1655 is similar to that of other IS30 family members. Moreover, it shows striking similarity to IS30 in transposition strategy even though their transposases differ in their N-terminal regions, which, for IS30, appears to determine target specificity. Comparative analysis of the transposases and the evolutionary aspects of sequence variants are also briefly discussed.     

Influence of hyperthyroidism on the effect of adenosine transport blockade assessed by a novel method in guinea pig atria

The aim of the present study was to investigate the effect of hyperthyroidism on the trans-sarcolemmal adenosine (Ado) flux via equilibrative and nitrobenzylthioinosine (NBTI)-sensitive nucleoside transporters (ENT1) in guinea pig atria, by assessing the change in the Ado concentration of the interstitial fluid ([Ado]_ISF) under nucleoside transport blockade with NBTI. For the assessment, we applied our novel method, which estimates the change in [Ado]_ISF utilizing the altered inotropic response to N⁶-cyclopentyladenosine (CPA), a relative stable selective agonist of A₁ Ado receptors, by providing a relative index, the equivalent concentration of CPA. Our results show an interstitial A do accumulation upon ENT1 blockade, which was more extensive in the hyperthyroid samples (CPA concentrations equieffective with the surplus [Ado]_ISF were two to three times higher in hyperthyroid atria than in euthyroid ones, with regard to the negative inotropic effect of CPA and Ado). This suggests an enhanced Ado influx via ENT1 in hyperthyroid atria. It is concluded that hyperthyroidism does not alter the prevailing direction of the Ado transport, moreover intensifies the Ado influx in the guinea pig atrium.