[Clinical study of enterovesical fistulas].

We conducted a retrospective review of 16 patients who were diagnosed with enterovesical fistula in our hospital between January 2000 and July 2013. The patient's median age was 74 years old and 4 were female. Most of the chief complaints were pneumaturia and fecaluria. There was a vesicosigmoidal fistula in 12 patients, an ileovesical fistula in 2, and a rectovesical fistula in 2. The main underlying cause was diverticulitis in 9 patients and a sigmoid colon carcinoma in 3. Diagnoses were made based on the findings of cystoscopy, barium enema, abdominal computed tomography and so on. Treatment varied in each case depending on the etiology and the patient's condition. The procedure was mostly open surgery, but laparoscopic sigmoidectomy was performed preserving the bladder in the two most recent cases.

Pro-oxidant copper-binding mode of the Apo form of ALS-linked SOD1 mutant H43R denatured at physiological temperature.

The mutation of Cu,Zn-superoxide dismutase (SOD1), a major antioxidant enzyme, is associated with amyotrophic lateral sclerosis (ALS). In a previous study, we showed that the metal-depleted apo form of an ALS-linked mutant, H43R, undergoes denaturation at physiological temperature (37 °C) in 90 min and acquires pro-oxidant activity in the presence of Cu(2+) and H2O2. In this study, we have examined the Cu(2+)-binding mode of denatured apo-H43R by circular dichroism (CD), fluorescent oxidation, UV Raman spectroscopy, and photooxidation. CD spectroscopy indicates that denatured apo-H43R loses native ß-barrel structure and the binding of Cu(2+) to the denatured apo form induces local refolding. Fluorescent-oxidation assays in the absence and presence of Cu(2+) chelators show that denatured apo-H43R contains two Cu(2+)-binding sites with higher and lower Cu(2+) affinities and with pro-oxidant activities in the reverse order. UV Raman spectroscopy gives evidence that His residues are bound to Cu(2+) mainly through the imidazole Nτ atom at the higher-affinity site and through the Nπ atom at the lower-affinity site, sharing one His residue with each other. The Cu(2+)-binding mode of denatured apo-H43R is analogous to but different from the Cu,Zn-binding mode of the native holo form. Photooxidation experiments confirm the involvement of His residues in the pro-oxidant activity. Taken together, it is suggested that the binding of Cu(2+) induces the local refolding of denatured apo-H43R to create toxic catalytic centers that convert the enzyme from antioxidant to pro-oxidant, leading to the pathogenesis of ALS. His residues are essential for both Cu(2+)-binding and pro-oxidant activities.

Involvement of histidine residues in the pH-dependent ß-galactoside binding activity of human galectin-1.

The pH dependence of the ß-galactoside binding activity of human galectin-1 (hGal-1) was investigated by fluorescence spectroscopy using lactose as a ligand. The obtained binding constant Kb was 2.94 ± 0.10 mM(-1) at pH 7.5. The Kb value decreased at acidic pH with a midpoint of transition at pH 6.0 ± 0.1. To elucidate the molecular mechanism of the pH dependence, we investigated the structures of hGal-1 and its two His mutants (H44Q and H52Q) using fluorescence, circular dichroism, UV absorption, and UV resonance Raman spectroscopy. Analysis of the spectra has shown that the pKa values of His44 and His52 are 5.7 ± 0.2 and 6.3 ± 0.1, respectively. The protonation of His52 below pH 6.3 induces a small change in secondary structure and partly reduces the galactoside binding activity. On the other hand, the protonation of His44 below pH 5.7 exerts a cation-π interaction with Trp68 and largely diminishes the galactoside binding activity. With reference to the literature X-ray structures at pH 7.0 and 5.6, protonated His52 is proposed to move slightly away from the galactoside-binding region with a partial unfolding of the ß-strand containing His52. On the other hand, protonated His44 becomes unable to form a hydrogen bond with galactoside and additionally induces a reorientation and/or displacement of Trp68 through cation-π interaction, leading to a loosening of the galactoside-binding pocket. These structural changes associated with His protonation are likely to be the origin of the pH dependence of the galactoside binding activity of hGal-1.

His-Trp cation-π interaction and its structural role in an α-helical dimer of HIV-1 Vpr protein.

Vpr is a multifunctional accessory protein of HIV-1 virus and was previously proposed to assume an antiparallel helical dimer with the third helices HIII of different subunits facing each other. In this study, we have examined the structure and stability of the antiparallel dimer by using a fragment peptide, Vpr52-80, spanning the HIII region. The present analyses of fluorescence, circular dichroism, and UV absorption spectra have shown that a cation-π interaction takes place between protonated His71 and Trp54 located near the opposite ends of the two antiparallel helices. The cation-π interaction induces a small elongation of the HIII helix, an increase in thermal stability of the helical dimer, and a modification of the helix arrangement to produce a more compact form. The His71-Trp54 cation-π interaction may be utilized in stabilizing and tuning the dimeric structure of Vpr to achieve proper interactions with other proteins.

Clear cell adenocarcinoma arising from abdominal wall endometriosis mimicking urachal tumor.

A 41-year-old woman presented with severe lower abdominal pain. She had a history of 2 cesarean deliveries. Magnetic resonance imaging (MRI) revealed a 4.3 × 4.6 × 4.8-cm mass on the urinary bladder dome. Preoperative diagnosis was invasive urachal tumor. Wide resection of the tumor was performed. The histopathological diagnosis was clear cell adenocarcinoma with endometriosis. MRI revealed normal-sized ovaries and uterus. The definite diagnosis of clear cell carcinoma arising from abdominal wall endometriosis was made. Adjuvant chemotherapy with paclitaxel and carboplatin (total 6 courses) was planned. The patient has thus far received 4 courses of this treatment.

Molecular magnetism of M6 hexagon ring in D(3d) symmetric [(MCl)6(XW9O33)2](12-) (M = Cu(II) and Mn(II), X = Sb(III) and As(III)).

Ferromagnetic [n-BuNH(3)](12)[(CuCl)(6)(SbW(9)O(33))(2)]·6H(2)O (1) and antiferromagnetic [n-BuNH(3)](12)[(MnCl)(6)(AsW(9)O(33))(2)]·6H(2)O (4) have been synthesized and structurally and magnetically characterized. Two complexes are structural analogues of [n-BuNH(3)](12)[(CuCl)(6)(AsW(9)O(33))(2)]·6H(2)O (2) and [n-BuNH(3)](12)[(MnCl)(6)(SbW(9)O(33))(2)]·6H(2)O (3) with their ferromagnetic interactions, first reported by us in 2006. (1) When variable temperature (T) direct current (dc) magnetic susceptibility (χ(M)) data are analyzed with the isotropic exchange Hamiltonian for the magnetic exchange interactions, χ(M)T vs T curves fitted by a full matrix diagonalization (for 1) and by the Kambe vector coupling method/Van Vleck's approximation (for 4) yield J = +29.5 and -0.09 cm(-1) and g = 2.3 and 1.9, respectively. These J values were significantly distinguished from +61.0 and +0.14 cm(-1) for 2 and 3, respectively. The magnetization under the pulsed field (up to 10(3) T/s) at 0.5 K exhibits hysteresis loops in the adiabatic process, and the differential magnetization (dM/dB) plots against the pulsed field display peaks characteristic of resonant quantum tunneling of magnetization (QTM) at Zeeman crossed fields, indicating single-molecule magnets for 1-3. High-frequency ESR (HFESR) spectroscopy on polycrystalline samples provides g(∥) = 2.30, g(⊥) = 2.19, and D = -0.147 cm(-1) for 1 (S = 3 ground state), g(∥) = 2.29, g(⊥) = 2.20, and D = -0.145 cm(-1) for 2 (S = 3), and g(∥) = 2.03 and D = -0.007 cm(-1) for 3 (S = 15). An attempt to rationalize the magnetostructural correlation among 1-4, the structurally and magnetically modified D(3d)-symmetric M (=Cu(II) and Mn(II))(6) hexagons sandwiched by two diamagnetic α-B-[XW(9)O(33)](9-) (X = Sb(III) and As(III)) ligands through M-(µ(3)-O)-W linkages, is made. The strongest ferromagnetic coupling for the Cu(6) hexagon of 2, the structure of which approximately provides the Cu(6)(µ(3)-O)(12) cylindrical geometry, is demonstrated by the polarization mechanism based on the point-dipole approximation, which provides a decrease of the ferromagnetic interaction due to the out-of-cylinder deviation of the Cu atoms for 1. The different nature of the magnetic exchange interaction in 3 and 4 is understood by the combined effect of the out-of plane deviation (the largest for 4) of the Mn atoms from the Mn(µ(3)-O)(2)Mn least-squares plane and the antiferromagnetic contribution arising from the large Mn-O-Mn bond angle. The primary contribution to D is discussed in terms of the magnetic dipole-dipole interaction between the electrons located on the magnetic sites in the M(6) hexagon.

Raman spectroscopic detection of the T-Hg II-T base pair and the ionic characteristics of mercury.

Developing applications for metal-mediated base pairs (metallo-base-pair) has recently become a high-priority area in nucleic acid research, and physicochemical analyses are important for designing and fine-tuning molecular devices using metallo-base-pairs. In this study, we characterized the Hg(II)-mediated T-T (T-Hg(II)-T) base pair by Raman spectroscopy, which revealed the unique physical and chemical properties of Hg(II). A characteristic Raman marker band at 1586 cm(-1) was observed and assigned to the C4=O4 stretching mode. We confirmed the assignment by the isotopic shift ((18)O-labeling at O4) and density functional theory (DFT) calculations. The unusually low wavenumber of the C4=O4 stretching suggested that the bond order of the C4=O4 bond reduced from its canonical value. This reduction of the bond order can be explained if the enolate-like structure (N3=C4-O4(-)) is involved as a resonance contributor in the thymine ring of the T-Hg(II)-T pair. This resonance includes the N-Hg(II)-bonded state (Hg(II)-N3-C4=O4) and the N-Hg(II)-dissociated state (Hg(II+) N3=C4-O4(-)), and the latter contributor reduced the bond order of N-Hg(II). Consequently, the Hg(II) nucleus in the T-Hg(II)-T pair exhibited a cationic character. Natural bond orbital (NBO) analysis supports the interpretations of the Raman experiments.

UV Raman markers for structural analysis of aromatic side chains in proteins.

UV Raman spectroscopy is a powerful tool for investigating the structures and interactions of the aromatic side chains of Phe, Tyr, Trp, and His in proteins. This is because Raman bands of aromatic ring vibrations are selectively enhanced with UV excitation, and intensities and wavenumbers of Raman bands sensitively reflect structures and interactions. Interpretation of protein Raman spectra is greatly assisted by using empirical correlations between spectra and structure. Many Raman bands of aromatic side chains have been proposed to be useful as markers of structures and interactions on the basis of empirical correlations. This article reviews the usefulness and limitations of the Raman markers for protonation/deprotonation, conformation, metal coordination, environmental polarity, hydrogen bonding, hydrophobic interaction, and cation-π interaction of the aromatic side chains. The utility of Raman markers is demonstrated through an application to the structural analysis of a membrane-bound proton channel protein.

Circular polariscopic analysis of strains in a semi-insulating SiC wafer: Its high potential to complement the information obtained from monochromatic x-ray topography.

We demonstrate that circular polariscopy is highly sensitive to strains in SiC wafers. In the monochromatic x-ray topographic analysis, which is regarded as a fundamental characterization method, the image information is disappeared in various areas: x-ray topography is not always suitable to evaluate wafer-size regions. Using circular polarizer plates, we apply the polariscopic analysis, which reveals the inhomogeneous strain distributed in the whole wafer region; namely, the circular polariscopic map has the high potential to complement the conventional monochromatic x-ray topograph. From the phonon-frequency shift observed in the Raman scattering spectra, the maximum stress is estimated to be ∼490 MPa. The crystal-plane distortion causing the strains is confirmed from the appearance of the forbidden reflections in the θ-2θ x-ray diffraction pattern.

Structural instability and Cu-dependent pro-oxidant activity acquired by the apo form of mutant SOD1 associated with amyotrophic lateral sclerosis.

Cu,Zn-superoxide dismutase (SOD1) is a cytosolic antioxidant enzyme, and its mutation has been implicated in amyotrophic lateral sclerosis (ALS), a disease causing a progressive loss of motor neurons. Although the pathogenic mechanism of ALS remains unclear, it is hypothesized that some toxic properties acquired by mutant SOD1 play a role in the development of ALS. We have examined the structural and catalytic properties of an ALS-linked mutant of human SOD1, His43Arg (H43R), which is characterized by rapid disease progression. As revealed by circular dichroism spectroscopy, H43R assumes a stable ß-barrel structure in the Cu(2+),Zn(2+)-bound holo form, but its metal-depleted apo form is highly unstable and readily unfolds or misfolds into an irregular structure at physiological temperature. The conformational change occurs as a two-state transition from a nativelike apo form to a denatured apo form with a half-life of ∼0.5 h. At the same time as the denaturation, the apo form of H43R acquires pro-oxidant potential, which is fully expressed in the presence of Cu(2+) and H(2)O(2), as monitored with a fluorogenic probe for detecting pro-oxidant activity. Comparison of d-d absorption bands suggests that the Cu(2+) binding mode of the denatured apo form is different from that of the native holo form. The denatured apo form of H43R is likely to provide non-native Cu(2+) binding sites where the Cu(2+) ion is activated to catalyze harmful oxidation reactions. This study raises the possibility that the structural instability and the resultant Cu-dependent pro-oxidant activity of the apo form of mutant SOD1 may be one of the pathogenic mechanisms of ALS.

Binding affinity and mode of distamycin A with A/T stretches in double-stranded DNA: importance of the terminal A/T residues.

Distamycin A (Dst) is an antibiotic which binds to the minor groove of double-stranded DNA at A/T-rich regions. We have examined the affinity and mode of Dst binding to DNA duplexes containing a conserved A/T core and variable terminal A/T regions by using circular dichroism spectroscopy. The observed circular dichroism spectra were analyzed by singular value decomposition and fitted to a two-step binding model. The result clearly shows a correlation between the affinity for Dst and the preference for Dst-DNA 1:1 binding over 2:1 binding. The A/T stretches that prefer 1:1 binding form high-affinity 1:1 complexes, whereas those preferring 2:1 binding form stable 2:1 complex with low overall affinities. The terminal A/T residues of the Dst binding region play an important role in the stabilization/destabilization of the 1:1 and 2:1 complexes, resulting in a terminal residue-dependent variation of the binding affinity and the binding mode preference.

[Conformational regulation of amyloid beta-peptide by lipid membranes and metal ions].

Conformational transition of monomeric amyloid beta-peptide (Abeta) to a self-associated beta-sheet structure is considered to be an initial step in the development of Alzheimer's disease. Several lines of evidence suggest that physiologically abundant lipid membranes and metal ions are involved in this step. We have demonstrated that Abeta binds to the phosphatidylcholine membrane in the lamellar gel phase but not in the liquid crystalline phase by using fluorescence and circular dichroism spectroscopy. The membrane-bound Abeta molecule takes alpha-helical or beta-sheet structure depending on the temperature. Tightly packed phosphatidylcholine membranes appear to serve as a platform for non-electrostatic binding and self-association of Abeta. We have also examined Zn(II) and Cu(II) binding modes of Abeta by Raman spectroscopy. The Raman spectra demonstrate that three histidine residues in the N-terminal region of Abeta provide primary metal binding sites. Zn(II) binds to the N(tau) atom of histidine and the peptide aggregates through intermolecular His-Zn-His bridges. In contrast, Cu(II) ion is chelated by the N(pi) atom of histidine and deprotonated main-chain amide nitrogens to form a soluble complex. Our findings on the conformational regulation of Abeta may help in better understanding the molecular basis for the development of Alzheimer's disease.

Activation of lactoperoxidase by heme-linked protonation and heme-independent iodide binding.

Lactoperoxidase (LPO), a mammalian secretory heme peroxidase, catalyzes the oxidation of thiocyanate by hydrogen peroxide to produce hypothiocyanate, an antibacterial agent. Although LPO is known to be activated at acidic pH and in the presence of iodide, the structural basis of the activation is not well understood. We have examined the effects of pH and iodide concentration on the catalytic activity and the structure of LPO. Electrochemical and colorimetric assays have shown that the catalytic activity is maximized at pH 4.5. The heme Soret absorption band exhibits a small red-shift at pH 5.0 upon acidification, which is ascribable to a structural transition from a neutral to an acidic form. Resonance Raman spectra suggest that the heme porphyrin core is slightly contracted and the Fe-His bond is strengthened in the acidic form compared to the neutral form. The structural change of LPO upon activation at acidic pH is similar to that observed for myeloperoxidase, another mammalian heme peroxidase, upon activation at neutral pH. Binding of iodide enhances the catalytic activity of LPO without affecting either the optimum pH of activity or the heme structure, implying that the iodide binding occurs at a protein site away from the heme-linked protonation site.

Incidence of upper urinary tract stone during 15 years in Tajima area, Japan: a hospital-based study.

Time trend of incidence of upper urinary tract stone during 15 years was evaluated by hospital-based cohort study in Tajima area, northern part of Hyogo prefecture, Japan, which has only two general hospitals with Department of Urology. Due to isolation in terms of traffic network and geographic circumstances, almost all patients with urinary stone in Tajima area are referred to the two hospitals. During the period 2005-2007, patients of the two hospitals with radiologically proven upper urinary tract stone were included in this study. The survey included the age and gender, location of stones, history of urinary stone, treatment received, and stone composition, if available. Annual incidence of upper urinary tract stone was estimated using the data of population census of Japan 2005 and compared with the data of Tajima during 1991-1993. 1,305 patients were included in this study. Age-adjusted incidence (+/-95% CI) was 157 (+/-22.4) for men, and 57 (+/-12.6) for women, compared with 141 (+/-20.7) for men, and 63 (+/-13.4) for women during 1991-1993. In total, 30.7% of patients received interventional treatment including shock wave lithotripsy, endoscopic lithotripsy and open surgery, whereas 25.3% in 1991-1993. Calcium oxalate/phosphate stone was 89.6%, struvite stone was 4.5%, cystine stone was 1.0%, uric acid stone was 4.0%, and others were 1.0%. In Tajima area, incidence of upper urinary tract stone has not changed during 15 years.

Interactions between histidine and tryptophan residues in the BM2 proton channel from influenza B virus.

The BM2 protein of influenza B virus forms a transmembrane proton channel essential for the virus infection. We investigated the structure and mechanism of the BM2 proton channel by using a 31-mer peptide (BM2-TMP) representing the putative transmembrane domain of BM2, with special focus on His19, Trp23 and His27. Like the full-length protein, BM2-TMP formed a transmembrane proton channel activated at acidic pH with a midpoint of transition at pH 6.4 +/- 0.1. Mutation of His19 to Ala almost abolished the channel activity, whereas the His27-to-Ala mutant retained partial activity. The proton selectivity of the channel was lost upon substitution of Phe for Trp23. Comparison of CD, fluorescence and Raman spectra measured for wild-type and mutated BM2-TMP at varied pH showed the pK(a) of the imidazole ring to be approximately 6.5 for His19 and approximately 7.6 for His27. Analysis of the pH-dependent fluorescence and Raman intensities suggested the occurrence of cation-pi interaction between the protonated imidazole ring of His and the indole ring of Trp. The His19-Trp23 cation-pi interaction below pH 6.5 is likely to trigger the opening of the proton channel, whereas His27 is not essential but enhances the channel activity through interaction with Trp23, which constitutes the proton-selective gate.

Evidence for the cation-pi interaction between Cu2+ and tryptophan.

The cation-pi interaction, a noncovalent interaction of electrostatic nature between a cation and an electron-rich pi system, is increasingly recognized as an important force that influences the structures and functions of molecules including proteins. Unlike other metal cations, the transition metal cation Cu2+ is not regarded to take part in a cation-pi interaction because Cu2+ tends to oxidize the pi electron system, in particular that of Trp, and to introduce covalency in the metal-pi electron interaction. This paper reports the first spectral evidence for the cation-pi interaction between Cu2+ and Trp. The Cu2+ ion bound to the amino N-terminal Cu2+/Ni2+ binding motif composed of three amino acid residues interacts with the indole ring of the fourth Trp residue in a noncovalent manner. The Cu2+-Trp interaction produces a distinct negative band at 223 nm in circular dichroism (CD), which disappears upon mutation or depletion of the Trp residue or upon replacement of the Cu2+ ion by Ni2+. In UV absorption, a pair of negative/positive intensity changes is generated at 222/231 nm by the Cu2+-Trp interaction, being consistent with the previous observations on the indole ring interacting with K+ or a cationic His imidazole ring. The negative CD band around 223 nm is characteristic of the Cu2+-Trp pair and may be useful as a marker of the Cu2+-Trp cation-pi interaction. Coordination of negatively charged ligands to Cu2+ is suggested to be important for the cation to be involved in a cation-pi interaction.

Non-electrostatic binding and self-association of amyloid beta-peptide on the surface of tightly packed phosphatidylcholine membranes.

Self-association of amyloid beta-peptide (Abeta) is considered to be an initial step in the development of Alzheimer's disease and is known to be promoted by negatively charged lipid membranes. We have examined the possibility of non-electrostatic Abeta-membrane interaction by using neutral phosphatidylcholine lipids. Fluorescence and circular dichroism spectra have clearly shown that Abeta binds to the phosphatidylcholine membrane in the lamellar gel phase but not in the ripple gel or liquid crystalline phase, indicating the importance of the tight lipid packing characteristic of the lamellar gel phase. The Abeta-membrane binding occurs at both low and high salt concentrations, ensuring the non-electrostatic nature of the interaction. The membrane-bound Abeta molecule takes a monomeric alpha-helical or self-associated beta-sheet structure depending on the temperature, peptide/lipid ratio, and salt concentration. The flat surface of tightly packed phosphatidylcholine membranes appears to serve as a platform for non-electrostatic binding and self-association of Abeta.

[Gluteal muscular metastasis from renal pelvic tumor].

We present a case of gluteal muscular metastasis from a renal pelvic tumor. A 57-year-old man had undergone right nephroureterectomy and received 2 courses of adjuvant chemotherapy (MEC: methotrexate, epirubicin, cisplatin) for invasive renal pelvic tumor. Five months after the operation, computed tomography (CT) revealed pulmonary metastasis and right adrenal gland recurrence. He underwent 2 courses of chemotherapy (gemcitabine, paclitaxel). Postchemotherapy-CT scan showed a 2.2 cm mass in the right gluteal muscle. Since the size of the pulmonary metastasis and right adrenal gland recurrence showed no change, the gluteal mass was excised. Pathological diagnosis was metastatic urothelial carcinoma. Adjuvant chemotherapy (TIN: paclitaxel, ifosfamide, nedaplatin) 3 courses were performed, but postchemotherapy-CT scan showed a new 2.4 cm mass in the right gluteal muscle. He received radiation therapy (total 30 Gy) for the new gluteal mass. The common metastatic sites of renal pelvic tumor are lungs, liver, bone, and lymph nodes. Gluteal muscle is an uncommon site of metastasis of urothelial carcinoma. This is the 1st case of gluteal muscle metastasis from renal pelvic tumor in the literature.

[Squamous cell carcinoma of the bladder presenting with spontanenous intraperitoneal bladder rupture: a case report].

A-90-year-old woman visited complaining of nausea, vomiting, and abdominal pain. She had abdominal rigidity and signs of generalized peritonitis. On computed tomography (CT) gastrointestinal perforation was denied and irregular thickness of the bladder wall was pointed out. Cystography was performed, but bladder rupture was not confirmed. Post-cystogram-CT revealed the leakage of contrast material in the peritoneal cavity from the urinary bladder. Spontaneous intraperitoneal bladder rupture was diagnosed. Cystoscopy was performed, but no information could be obtained due to severe cloudy urine. Open laparotomy was performed. At surgery, cloudy fluid was aspirated from the abdominal cavity. Abdominal organs were normal when explored, but a small perforation was found on the vault of the bladder and primary closure was performed. Postoperatively, cystoscopy was performed again after the medication with antibiotics. A huge, nonpapillary tumor was seen on the left lateral wall. Tumor biopsy was performed. Histological examination of specimens revealed squamous cell carcinoma. On abdominal CT, invasive bladder carcinoma, left hydronephrosis and hydroureter were pointed out. Considering her age, general health status and prognosis, only right ureterocutaneostomy was performed.