Acute plastic bronchitis.

Plastic bronchitis is a rare disorder characterized by the formation of bronchial cast. The etiology is obscure, though usually associated with conditions like asthma, aspergillosis, pneumonia, cystic fibrosis and cardiac problems.

Identification and characterisation of a group of cervical carcinoma patients with profound downregulation of intratumoral Type 1 (IFNgamma) and Type 2 (IL-4) cytokine mRNA expression.

Type 1 cytokines, such as interferon gamma (IFNgamma) and interleukin-2 (IL-2), increase T cell-mediated immune responses and are considered to be beneficial for antitumour immunity. Type 2 cytokines, such as IL-4, IL-5, and IL-10, inhibit Type 1 responses and promote humoral responses. We have previously reported an association between low intratumoral IFNgamma mRNA levels and poor clinical outcome in patients with invasive cervical carcinoma. In this study, by using quantitative polymerase chain reaction (PCR), we identified a group of cervical carcinoma patients with undetectable intratumoral T cell-derived cytokine mRNAs, as IFNgamma, IL-4 and IL-17 expression could not be detected in 5, 25 and 8 of the 52 biopsies analysed, respectively. Global downregulation of Type 1 and Type 2 cytokines was observed in a subgroup of patients who more frequently presented advanced stage tumours. Biopsies of patients with no IFNgamma gene expression did not appear to be less infiltrated by T cells than control biopsies with measurable IFNgamma gene expression. These results clearly demonstrate that, in some clinical situations, the decrease in intratumoral Type 1 cytokines is not associated with a Type 2 polarisation, but rather reflects global deactivation of T cells at the tumour site. These data provide support for immunotherapy protocols designed to reverse the anergic state of T cells in cancer.

Synthesis and characterization of oligonucleotides containing formamidopyrimidine lesions (Fapy.dA, Fapy.dG) at defined sites.

The preparation of oligonucleotides containing Fapy.dA (N4-(2-Deoxy-alpha,beta-D-erythro-pentofuranosyl)-4,6-diamino- 5-formamidopyrimidine) and Fapy.dG (N6-(2-Deoxy-alpha,beta-D-erythro-pento-furanosyl)-2,6- diamino-4-hydroxy-5-formamido-pyrimidine) at defined sites was achieved by introducing the lesions as dinucleotide phosphoramidites. Oligonucleotides as composed of as many as 36-nucleotides were prepared by solid-phase synthesis and/or a combination of chemical synthesis and enzymatic ligation. Oligonucleotides containing non-hydrolyzable analogues were also prepared. Oligonucleotides containing these modified nucleotides were characterized by a variety of chemical and biochemical methods.

AlkA protein is the third Escherichia coli DNA repair protein excising a ring fragmentation product of thymine.

Various forms of oxidative stress lead to the formation of damaged bases including N-(2-deoxy-beta-D-erythro-pentofuranosyl)-N-3-(2R-hydroxyisobutyric acid)-urea or alphaRT, the fragmentation product of thymine formed from 5R-thymidine C5-hydrate upon hydrolysis. It was shown that alphaRT is excised by Escherichia coli Fpg and Nth proteins. Here we report that when present in DNA, alphaRT is, in addition, a substrate for the E. coli AlkA protein with an apparent K(m) value of congruent with170 nM. alphaRT positioned opposite T, dG, dC, and dA were efficiently excised by AlkA protein from duplex oligodeoxynucleotides in the following order: dA approximately T >> dC approximately dG. This is the first example of the excision of a ring opened form of a pyrimidine by AlkA protein and also the first example where the same DNA base lesion is excised by three different DNA glycosylases of the base excision repair pathway. The present results suggest possible structural similarity of the active site between E. coli AlkA, Fpg, and Nth proteins.

The effects of 5R-5,6-dihydro-5-hydroxythymidine on duplex DNA stability and structure.

An improved method for the chemical synthesis of oligodeoxynucleotides containing 5 R -5,6-dihydro-5-hydroxythymidine (1) at a defined site is reported. UV melting studies carried out on duplexes containing1synthesized in this manner correlate with previously reported enzyme inhibition experiments, as well as computational studies. The melting experiments suggest that1destabilizes duplex DNA, but that the lesion preferentially base pairs to deoxyadenosine. These experiments also suggest that the presence of1in a duplex disrupts base pairing at the 5'-adjacent nucleotide and results in the thermally preferred misincorporation of purines opposite the 5'-deoxyadenosine stacked above 1 at this position. Despite the disruptions in base stacking, the UV melting experiments and enzymatic ligation/electrophoretic migration assays are consistent with the predicted macroscopic duplex structure containing intrahelical nucleotides.

Binding affinities of gallotannin analogs with bovine serum albumin: ramifications for polyphenol-protein molecular recognition.

A series of gallotannin analogs were prepared by chemical synthesis, and their affinity for the test-case protein bovine serum albumin was measured by equilibrium dialysis. The structure/activity data obtained suggest that the naturally occurring gallotannins, in fact, do not represent the optimal protein recognition agents amongst polyphenolated templates.