[A case of hemolysis and acute kidney disease caused by rectal damage due to glycerin enema].

A male patient in his sixties with a long-term history of schizophrenia had been received glycerin enema once or twice a week in a mental hospital. He was emergently transferred to our hospital due to fever, vomiting, hematuria, and dyspnea. Laboratory findings on admission showed an elevation of white blood cells indicating inflammation, hemolysis, and renal dysfunction.

The structure of metallo-DNA with consecutive thymine-HgII-thymine base pairs explains positive entropy for the metallo base pair formation.

We have determined the three-dimensional (3D) structure of DNA duplex that includes tandem Hg(II)-mediated T-T base pairs (thymine-Hg(II)-thymine, T-Hg(II)-T) with NMR spectroscopy in solution. This is the first 3D structure of metallo-DNA (covalently metallated DNA) composed exclusively of 'NATURAL' bases. The T-Hg(II)-T base pairs whose chemical structure was determined with the (15)N NMR spectroscopy were well accommodated in a B-form double helix, mimicking normal Watson-Crick base pairs.

Specific interactions between silver(I) ions and cytosine-cytosine pairs in DNA duplexes.

Very specific binding of the Ag(i) ion unexpectedly stabilized DNA duplexes containing the naturally occurring cytosine-cytosine (C-C) mismatch-base pair; because the C-C pair selectively binds to the Ag(i) ion, we developed a DNA-based Ag(i) sensor that employed an oligodeoxyribonucleotide containing C-C pairs used for Ag(i) binding sites.

Structural and physicochemical features on the metal-mediated base pairs.

The chemical structure of the mercury-mediated T-T pair (T-Hg(I)I-T) was determined with (15)N NMR spectroscopy. In order to determine the chemical structure of the T-Hg(I)I-T pair, (15)N-(15)N J-coupling across a metal center (2JNN) was employed. Notably, this is the first observation of (2)J(NN) in a biological macromolecule (DNA duplex).

Spectroscopic analysis of AgI-DNA complex.

It has recently been reported that C-C mismatches were able to recognize Ag(I) specifically, and form Ag(I)-mediated cytosine-cytosine base pairs (C-Ag(I)-C pair). In this study, we explored DNA sequences, which are appropriate for structural studies of this new type of metal-mediated base pairs. For this experiments, we synthesized four kinds of DNA duplexes including a single C-C mismatch.

Structural analyses on the mercuryII-mediated T-T base pair.

Recently, it was reported that T-T mismatches can specifically recognize Hg(II), and form T-Hg(II)-T pairs. In order to understand the structure and properties of the T-Hg(II)-T pair, we measured NMR spectra for a DNA duplex, d(CGCGTTGTCC) x d(GGACTTCGCG), with two successive T-T mismatches (Hg(II)-binding sites) in the middle of the duplex. We identified imino proton resonances of the T-T mismatches in mercury-free duplex, and performed titration experiments with Hg(II) by using 1-dimensional (1D) (1)H NMR spectra.

Spectroscopic analyses of DNA duplexes in the presence of mercury ions.

The DNA duplex with tandem T x T mismatches in the presence of Hg(II) has been studied by NMR spectroscopy. For this study, we synthesized decamer duplex with two successive T x T mismatches (TT10). From two-dimensional (2D) 1H-1H NOESY spectrum of TT10 in complex with Hg(II), we were able to trace sequential NOE walks between base protons and anomeric protons (H1'), and assigned all of them.

NMR spectroscopic analyses of functional nucleic acids-metal interaction and their solution structure analyses.

We have studied complexations of functional nucleic acids and metal ions, by means of NMR spectroscopy. In the case of hammerhead ribozymes, they have a metal ion-binding motif in their core sequences. Upon the metallation of N7 of a guanosine in an RNA duplex modelled after hammerhead ribozymes, 20 ppm higher field shift of N7 was observed in 1-dimensional (1D) 15N NMR spectra.

Spectroscopic analysis of DNA duplexes including T-T mismatches.

The DNA duplex with tandem T x T mismatches has been studied by NMR spectroscopy. For this study, we synthesized decamer duplex with two successive T x T mismatches, TT10:d(CGCGTTGTCC) x d(GGACTTCGCG). From two-dimensional (2D) 1H-1H NOESY spectrum, we were able to trace sequential NOE walks between base protons and anomeric protons (H1'), and assigned all the base protons and anomeric protons.

NMR spectroscopic study of a DNA duplex with mercury-mediated T-T base pairs.

Recently, we reported that T-T mismatches can specifically recognize Hg(II) (T-Hg(II)-T pair formation). In order to understand the properties of the T-Hg(II)-T pair, we recorded NMR spectra for a DNA duplex, d(CGCGTTGTCC).d(GGACTTCGCG), with two successive T-T mismatches (Hg (II)-binding sites).

MercuryII-mediated formation of thymine-HgII-thymine base pairs in DNA duplexes.

The very specific binding of the HgII ion unexpectedly and significantly stabilizes naturally occurring thymine-thymine base mispairing in DNA duplexes. Following this finding, we prepared DNA duplexes containing metal-mediated base pairs at the desired sites, as well as novel double helical architectures consisting only of thymine-HgII-thymine pairs.