Immunohistochemical expression of matrix metalloproteinases in the granulomatous rosacea compared with the non-granulomatous rosacea

BACKGROUND

There is a granulomatous variant which is recognized in the rosacea spectrum. However, the pathogenesis of granuloma formation in rosacea has not been clearly demonstrated. Matrix metalloproteinases (MMPs) are required for recruitment of inflammatory cells and for tissue remodelling, making way for the development of well-organized granuloma.

OBJECTIVE

The aim of this study was to investigate the expression of transforming growth factor (TGF)-β, TGF-β type II receptor (TβRII), Tumour necrosis factor (TNF)-α, MMP-1, 2 and 9 in the granulomatous rosacea (GR) compared with the non-granulomatous rosacea (NGR) and test the hypothesis that the changes of these profiles in GR would be related with chronic ultraviolet radiation (UVR)-exposure.

METHODS

Facial skin samples were obtained from 20 patients with GR and NGR (control group). The sections were stained using haematoxylin and eosin, Verhoeff's elastic stain, and antibodies to TGF-β, TβRII, TNF-α, MMP-1, -2 and -9.

RESULTS

The amount of elastotic material was significantly increased in the dermis of GR lesions. Expression of TGF-β was significantly decreased in the epidermis of GR lesions compared with NGR lesions. In addition, the expression of MMP-9 was significantly increased in the dermis of GR lesions compared with NGR lesions, especially at the centre of the granuloma on a semi-quantitative analysis. MMP-2 expression was also increased in GR lesions, although the difference between the two groups was not statistically significant.

CONCLUSIONS

The results of this study suggest that the increased expression of MMPs in the dermis may participate in granuloma formation of GR in association with UVR.

Aluminum oxide formation at Al/La(1-x)Sr(x)MnO3 interface: a computational study for resistance random access memory applications

Resistance random access memory (ReRAM) is emerging as a next-generation nonvolatile memory. One of the most promising materials for the ReRAM application is a composite of a reactive metal [such as aluminum (Al)] and a mixed-valance manganite [such as La(1-x)Ca(x)MnO3 (LCMO) and La(1-x)Sr(x)MnO3 (LSMO)]. One of the current hypotheses regarding the origin of the resistive switching of such systems is a voltage-controlled reversible formation of a high-resistance aluminum oxide (AlO(x)) layer at the Al/LC(S)MO interface through oxygen migration from LC(S)MO. To validate this hypothesis, quantum mechanics (density functional theory) calculations were carried out on an atomistic model of the resistive-switching phenomena at the Al/LSMO interface (the composite systems of Al/LSMO and AlO(x)/LSMO) as well as on the component materials such as Al, AlO(x), LaMnO3, LaMnO(3-delta), La(1-x)Sr(x)MnO3, and La(1-x)Sr(x)MnO(3-delta). The changes in the structure, energy, and electronic structure of these systems during the oxygen vacancy formation in LSMO, the oxygen migration through the Al/LSMO interface, and the AlO(x) formation were investigated.

Survey of rice proteins interacting with OsFCA and OsFY proteins which are homologous to the Arabidopsis flowering time proteins, FCA and FY

The FCA protein is involved in controlling flowering time and plays more general roles in RNA-mediated chromatin silencing in Arabidopsis. It contains two RNA-binding domains and a WW domain. The FCA protein interacts with FY, a polyadenylation factor, via its WW domain. We previously characterized a rice gene, OsFCA, which was homologous to FCA. Here, we found that the OsFCA protein could interact through its WW domain with the following proteins: OsFY, a protein containing a CID domain present in RNA-processing factors such as Pcf11 and Nrd1; a protein similar to splicing factor SF1; a protein similar to FUSE splicing factor; and OsMADS8. The FY protein is associated with the 3' end processing machinery in Arabidopsis. Thus, we examined interactions between OsFY and the rice homologs (OsCstF-50, -64 and -77) of the AtCstF-50, -64 and -77 proteins. We found that OsFY could bind OsCstF50, whereas the OsCstF77 protein could bridge the interaction between OsCstF50 and OsCstF64. Taken together, our data suggest that OsFCA could interact with several proteins other than OsFY through its WW domain and may play several roles in rice.

Abscisic acid does not disrupt either the Arabidopsis FCA-FY interaction or its rice counterpart in vitro

We examined the effect of (+)-ABA on the in vitro interaction of rice FCA and FY homologs, OsFCA and OsFY. From this analysis, we found no disruption of the OsFCA-OsFY complexes by ABA treatment. This result prompted us to examine the effect of ABA on the FCA-FY interaction. In these experiments, we could not reproduce the inhibitory effect of (+)-ABA on the interaction between FCA and FY. Based on these combined results, we believe that the inhibitory effect of (+)-ABA on the FCA-FY interaction should be cautiously reconsidered.

The rate of Salmonella spp. infection in zoo animals at Seoul Grand Park, Korea

Salmonellosis is an important zoonotic disease that affects both people and animals. The incidence of reptile-associated salmonellosis has increased in Western countries due to the increasing popularity of reptiles as pets. In Korea, where reptiles are not popular as pets, many zoos offer programs in which people have contact with animals, including reptiles. So, we determined the rate of Salmonella spp. infection in animals by taking anal swabs from 294 animals at Seoul Grand Park. Salmonella spp. were isolated from 14 of 46 reptiles (30.4%), 1 of 15 birds (6.7%) and 2 of 233 mammals (0.9%). These findings indicate that vigilance is required for determining the presence of zoonotic pathogen infections in zoo animals and contamination of animal facilities to prevent human infection with zoonotic diseases from zoo facilities and animal exhibitions. In addition, prevention of human infection requires proper education about personal hygiene.

OsCO3, a CONSTANS-LIKE gene, controls flowering by negatively regulating the expression of FT-like genes under SD conditions in rice

The photoperiod is an important environmental stress that determines flowering time. The CONSTANS (CO) and Heading date 1 (Hd1) genes are known to be central integrators of the photoperiod pathway in Arabidopsis and rice, respectively. Although they are both members of the CONSTANS-LIKE (COL) family and have two B-boxes and a CCT domain, rice also possesses novel COL genes that are not found in Arabidopsis. Here, we demonstrate that a novel COL gene, OsCO3, containing a single B-box and a CCT domain, modulates photoperiodic flowering in rice. The circadian expression pattern of OsCO3 mRNA oscillated in a different phase from Hd1 and was similar to that of OsCO3 pre-mRNA, suggesting that the diurnal expression pattern of OsCO3 transcripts may be regulated at the transcriptional level. Overexpression of OsCO3 specifically caused late flowering under short day (SD) conditions relative to wild-type rice plants. The expression of Hd3a and FTL decreased in these transgenic plants, whereas the expression of Hd1, Early heading date 1 (Ehd1), OsMADS51, and OsMADS50 did not significantly change. Our results suggest that OsCO3 primarily controls flowering time under SD conditions by negatively regulating Hd3a and FTL expression, independent of the SD-promotion pathway.

Analytical model development for the prediction of the frictional resistance of a capsule endoscope inside an intestine

For the purpose of optimizing the design of the locomotion mechanism as well as the body shape of a self-propelled capsule endoscope, an analytical model for the prediction of frictional resistance of the capsule moving inside the small intestine was first developed. The model was developed by considering the contact geometry and viscoelasticity of the intestine, based on the experimental investigations on the material properties of the intestine and the friction of the capsule inside the small intestine. In order to verify the model and to investigate the distributions of various stress components applied to the capsule, finite element (FE) analyses were carried out. The comparison of the frictional resistance between the predicted and the experimental values suggested that the proposed model could predict the frictional force of the capsule with reasonable accuracy. Also, the FE analysis results of various stress components revealed the stress relaxation of the intestine and explained that such stress relaxation characteristics of the intestine resulted in lower frictional force as the speed of the capsule decreased. These results suggested that the frontal shape of the capsule was critical to the design of the capsule with desired frictional performance. It was shown that the proposed model can provide quantitative estimation of the frictional resistance of the capsule under various moving conditions inside the intestine. The model is expected to be useful in the design optimization of the capsule locomotion inside the intestine.

Electrochemical detection of pathogen infection using cell chip

The immobilized cell using self-assembled synthetic oligopeptide was applied to the electrochemical detection of pathogen infection. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for the immobilization of HeLa cell on gold (Au) substrate. Layer formation and immobilization of the cell were investigated with surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS). Experimental results showed that the thin film of cysteine-terminated synthetic oligopeptide was successfully fabricated and it could be applied for the immobilization of HeLa cells. The adhered living cell was exposed to E. coli O157:H7, which induced the change of SPR angle and electrochemical impedance signal. The proposed cell immobilization method using self-assembly technique can be applied to construct the cell microarray for on-site pathogen monitoring.

Polyphenol (-)-epigallocatechin gallate protection from ischemia/reperfusion-induced renal injury in normotensive and hypertensive rats

INTRODUCTION

The effect of epigallocatechin gallate (EGCG) in an in vivo renal model of ischemia with reperfusion (I/R) was compared between normotensive (WKR) and hypertensive (SHR) rats.

METHODS

WKR (groups I, II, III) and SHR groups (groups IV, V, VI) were divided into three types. Groups I and IV were sham-operated animals; groups II and V were subjected to 45 minutes of renal I/R; and groups III and VI received 10 mg/kg EGCG intravenously at the time of reperfusion. Three days after renal I/R, we compared renal function markers, malondialdehyde (MDA), and histologic changes.

RESULTS

Following renal I/R, levels of blood urea nitrogen (BUN) and serum creatinine (sCr) were increased and serum creatinine clearance (CrCl) decreased in group V compared to group II (P < .001). Those receiving EGCG treatment (groups III and VI) had decreased BUN and sCr compared to non-EGCG I/R groups (P < .001), but not surprisingly, higher than sham groups. CrCl was lowest in the SHR groups. The MDA was significantly decreased after EGCG treatment (P = .028 in group III, P = .002 in group VI). Following renal I/R, tissue necrosis was more severe among SHR (P < .001). However, the ratio of regeneration to damage significantly increased in SHR after EGCG treatment.

CONCLUSIONS

The reperfusion injury was greater among SHR compared with WKR in terms of renal function, lipid peroxidation, and tissue damage. EGCG treatment significantly ameliorated renal impairment and promoted tissue regeneration following renal I/R.

Mechanism of Oxidative Shuttling for [2]Rotaxane in a Stoddart−Heath Molecular Switch: Density Functional Theory Study with Continuum-Solvation Model

The central component of the programmable molecular switch demonstrated recently by Stoddart and Heath is [2]rotaxane, which consists of a cyclobis-(paraquat-p-phenylene) ring-shaped shuttle [(CBPQT(4+))(PF(6)(-))(4)] encircling a finger and moving between two stations on the finger: tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP). We report here a quantum mechanics (QM) study of the mechanism by which movement of the ring (and in turn the on-off switching) is controlled by the oxidation-reduction process. We use B3LYP density functional theory to describe how oxidation of the [2]rotaxane components (in using Poisson-Boltzmann continuum-solvation theory for acetonitrile solution) induces the motions associated with switching (translation of the ring). These calculations support the proposal that oxidation occurs on TTF, leading to repulsion between two positive charge centers (TTF(2+) and CBPQT(4+)) that drives the CBPQT(4+) ring from the TTF(2+) station toward the neutral DNP station. The theory also supports the experimental observation that the first and second oxidation potentials are nearly the same (separated by 0.09 eV in the QM). This excellent agreement between the QM and experiment suggests that QM can be useful in designing new systems.

Molecular Dynamics Simulation of Amphiphilic Bistable [2]Rotaxane Langmuir Monolayers at the Air/Water Interface

Bistable [2]rotaxanes display controllable switching properties in solution, on surfaces, and in devices. These phenomena are based on the electrochemically and electrically driven mechanical shuttling motion of the ring-shaped component, cyclobis(paraquat-p-phenylene) (CBPQT(4+)), between a monopyrrolotetrathiafulvalene (mpTTF) unit and a 1,5-dioxynaphthalene (DNP) unit located along a dumbbell component. The most stable state of the rotaxane (CBPQT(4+)@mpTTF) is that in which the CBPQT(4+) ring encircles the mpTTF unit, but a second less favored metastable co-conformation with the CBPQT(4+) ring surrounding the DNP (CBPQT(4+)@DNP) can be formed experimentally. For both co-conformations of an amphiphilic bistable [2]rotaxane, we report here the structure and surface pressure-area isotherm of a Langmuir monolayer (LM) on a water subphase as a function of the area per molecule. These results from atomistic molecular dynamics (MD) studies are validated by comparing with experiments based on similar amphiphilic rotaxanes. For both co-conformations, we found that as the area per molecule increases the thickness of the LM decreases while the molecular tilt increases. Both co-conformations led to similar LM thicknesses at the same packing area. From the simulated LM systems, we calculated the electron density profiles of the monolayer as a function of area per molecule, which show good agreement with experimental analyses from synchrotron X-ray reflectivity measurements of related systems. Decomposing the overall electron density profiles into component contributions, we found distinct differences in molecular packing in the film depending upon the co-conformation. Thus we find that the necessity of allowing the tetracationic ring to become solvated by water leads to differences in the structures for the two co-conformations in the LM. At the same packing area, the value of the overall tilt angle does not seem to be sensitive to whether the CBPQT(4+) ring is encircling the mpTTF or the DNP unit. However, the conformation of the dumbbell does depend on the location of the CBPQT(4+) ring, which is reflected in the segmental tilt angles of the mpTTF and DNP units. Using the Kirkwood-Buff formula in conjunction with MD calculations, we find the surface pressure-area isotherms for each co-conformation in which the CBPQT(4+)@mpTTF form has smaller surface tension and therefore larger surface pressure than the CBPQT(4+)@DNP at the same packing area, differences that decreases with increasing area per molecule, which is verified experimentally.

First-principles study of the switching mechanism of [2]catenane molecular electronic devices

We present a first-principles study of the coherent charge transport properties of bistable [2]catenane molecular monolayers sandwiched between Au(111) electrodes. We find that conduction channels around the Fermi level are dominated by the two highest occupied molecular orbital levels from tetrathiafulvalene (TTF) and dioxynaphthalene (DNP) and the two lowest unoccupied molecular orbital levels from tetracationic cyclophane (CBPQT4+), and the OFF to ON switching results from the energetic shifts of these orbitals as CBPQT4+ moves from TTF to DNP. We show that the superposition principle can be adopted for predicting the function of the composite device.

Molecular Dynamics Simulation Study on a Monolayer of Half [2]Rotaxane Self-Assembled on Au(111)

The self-assembled monolayer (SAM) structure of the tetrathiafulvalene-side half of the Stoddart-Heath type [2]rotaxane on Au(111) surface was investigated using molecular dynamics (MD) simulations. We find that the orientation of the cyclobis(paraquat-p-phenylene) (CBPQT) ring depends dramatically on the coverage, changing in order to obtain highly packed SAMs. The ring lies with its large hollow parallel to the surface at lower coverage (up to one CBPQT per 27 surface Au atoms with a footprint of 1.9 nm(2); 1/27) when free space is available around it, but as the coverage increases (up to one CBPQT per 12 surface Au atoms with a footprint of 0.9 nm(2); 1/12), it tilts completely around its axis and lies with its smaller side (paraquat or phenyl ring) parallel to the surface to accommodate the reduced area available. We find that the best packing densities correspond to one CBPQT per 12-18 surface Au atoms (1/18-1/12) with footprints in the range between 0.9 nm(2) and 1.3 nm(2).

Structures and Properties of Self-Assembled Monolayers of Bistable [2]Rotaxanes on Au (111) Surfaces from Molecular Dynamics Simulations Validated with Experiment

Bistable [2]rotaxanes display controllable switching properties in solution, on surfaces, and in devices. These phenomena are based on the electrochemically and electrically driven mechanical shuttling motion of the ring-shaped component, cyclobis(paraquat-p-phenylene) (CBPQT(4+)) (denoted as the ring), between a tetrathiafulvalene (TTF) unit and a 1,5-dioxynaphthalene (DNP) ring system located along a dumbbell component. When the ring is encircling the TTF unit, this co-conformation of the rotaxane is the most stable and thus designated the ground-state co-conformer (GSCC), whereas the other co-conformation with the ring surrounding the DNP ring system is less favored and so designated the metastable-state co-conformer (MSCC). We report here the structure and properties of self-assembled monolayers (SAMs) of a bistable [2]rotaxane on Au (111) surfaces as a function of surface coverage based on atomistic molecular dynamics (MD) studies with a force field optimized from DFT calculations and we report several experiments that validate the predictions. On the basis of both the total energy per rotaxane and the calculated stress that is parallel to the surface, we find that the optimal packing density of the SAM corresponds to a surface coverage of 115 A(2)/molecule (one molecule per 4 x 4 grid of surface Au atoms) for both the GSCC and MSCC, and that the former is more stable than the latter by 14 kcal/mol at the optimum packing density. We find that the SAM retains hexagonal packing, except for the case at twice the optimum packing density (65 A(2)/molecule, the 3 x 3 grid). For the GSCC and MSCC, investigated at the optimum coverage, the tilt of the ring with respect to the normal is theta = 39 degrees and 61 degrees, respectively, while the tilt angle of the entire rotaxane is psi = 41 degrees and 46 degrees , respectively. Although the tilt angle of the ring decreases with decreasing surface coverage, the tilt angle of the rotaxane has a maximum at 144 A(2)/molecule (the 4 x 5 grid/molecule) of 50 degrees and 51 degrees for the GSCC and MSCC, respectively. The hexafluorophosphate counterions (PF(6)(-)) stay localized around the ring during the 2 ns MD simulation. On the basis of the calculated density profile, we find that the thickness of the SAM is 40.5 A at the optimum coverage for the GSCC and 40.0 A for MSCC, and that the thicknesses become less with decreasing surface coverage. The calculated surface tension at the optimal packing density is 45 and 65 dyn/cm for the GSCC and MSCC, respectively. This difference suggests that the water contact angle for the GSCC is larger than for the MSCC, a prediction that is verified by experiments on Langmuir-Blodgett monolayers of amphiphilic [2]rotaxanes.

Synthesis of Ru(II) Complexes of N-Heterocyclic Carbenes and Their Promising Photoluminescence Properties in Water

Novel complexes 1 and 2 based on N-heterocyclic carbenes, which are analogous to Ru(bpy)(3)(2+) and Ru(terpy)(2)(2+), respectively, were synthesized. The complex, which is analogous to Ru(terpy)(2)(2+), exhibited promising photoluminescence properties with a long lifetime of 820 ns in acetonitrile and 3100 ns in water at room temperature, respectively. In addition, ab initio calculations were carried out.

Density Functional Theory Studies of the [2]Rotaxane Component of the Stoddart−Heath Molecular Switch

The central component of the programmable molecular switch recently demonstrated by Stoddart and Heath is [2]rotaxane, which consists of a cyclobis(paraquat-p-phenylene) shuttle (CBPQT(4+))(PF(6)(-))(4) (the ring) encircling a finger and moving between two stations, tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP). As a step toward understanding the mechanism of this switch, we report here its electronic structure using two flavors of density functional theory (DFT): B3LYP/6-31G and PBE/6-31G. We find that the electronic structure of composite [2]rotaxane can be constructed reasonably well from its parts by combining the states of separate stations (TTF and DNP) with or without the (CBPQT)(PF(6))(4) shuttle around them. That is, the "CBPQT@TTF" state, (TTF)(CBPQT)(PF(6))(4)-(DNP), is described well as a combination of the (TTF)(CBPQT)(PF(6))(4) complex and free DNP, and the "CBPQT@DNP" state, (TTF)-(DNP)(CBPQT)(PF(6))(4), is described well as a combination of free TTF and the (DNP)(CBPQT)(PF(6))(4) complex. This allows an aufbau or a "bottom-up" approach to predict the complicated [n]rotaxanes in terms of their components. This should be useful in designing new components to lead to improved properties of the switches. A critical function of the (CBPQT(4+))(PF(6)(-))(4) shuttle in switching is that it induces a downshift of the frontier orbital energy levels of the station it is on (TTF or DNP). This occurs because of the net positive electrostatic potential exerted by the CBPQT(4+) ring, which is located closer to the active station than the four PF(6)(-)'s. This downshift alters the relative position of energy levels between TTF and DNP, which in turn alters the electron tunneling rate between them, even when the shuttle is not involved directly in the actual tunneling process. Based on this switching mechanism, the "CBPQT@TTF" state is expected to be a better conductor since it has better aligned levels between the two stations. A second potential role of the (CBPQT(4+))(PF(6)(-))(4) shuttle in switching is to provide low-lying LUMO levels. If the shuttle is involved in the actual tunneling process, the reduced HOMO-LUMO gap (from 3.6 eV for the isolated finger to 1.1 eV for "CBPQT@TTF" or to 0.6 eV for "CBPQT@DNP" using B3LYP) would significantly facilitate the electron tunneling through the system. This might occur in a folded conformation where a direct contact between free station and the shuttle on the other station is possible. When this becomes the main switching mechanism, we expect the "CBPQT@DNP" state to become a better conductor because its HOMO-LUMO gap is smaller and because its HOMO and LUMO are localized at different stations (HOMO exclusively at TTF and LUMO at CBPQT encircling DNP) so that the HOMO-to-LUMO tunneling would be through the entire molecule of [2]rotaxane. Thus an essential element in designing these switches is to determine the configuration of the molecules (e.g., through self-assembled monolayers or incorporation of conformation stabilizing units).

First Principles Calculations of the pKa Values and Tautomers of Isoguanine and Xanthine

The accurate replication of DNA requires the formation of complementary hydrogen bonds between a template base and the base moiety of an incoming deoxynucleotide-5'-triphosphate. Recent structural studies suggest that some DNA polymerases contribute additional constraints by interrogating the minor groove face of the incoming and template bases. Therefore, the hydrogen bond-donating or -accepting properties of the base pairing as well as minor groove faces of the bases could be important determinants of correct base selection. In this paper, we investigate two purines that could arise by endogenous damage of the normal DNA bases: isoguanine (which can be generated by the oxidation of adenine) and xanthine (which can be generated by the deamination of guanine). In both cases, the potential exists for the placement of a proton in the N3 position, converting the N3 position from a hydrogen bond acceptor to a donor. In this paper, we use first principles quantum mechanical methods (density functional theory using the B3LYP functional and the 6-31G++Gbasis set) to predict the ionization and tautomeric equilibria of both isoguanine and xanthine in the gas phase and aqueous solution. For isoguanine, we find that the N1H and N3H neutral tautomeric forms are about equally populated in aqueous solution, while the enol tauotomers are predominant in the gas phase. In contrast, we find that xanthine displays essentially no tautomeric shifts in aqueous solution but is nearly equally populated by both an anionic and a neutral form at physiological pH. To obtain these results, we carried out an extensive examination of the tautomeric and ionic configurations for both xanthine and isoguanine in solution and in the gas phase. The potential hydrogen-bonding characteristics of these damaged purines may be used to test predictions of the important components of base selection by different DNA polymerases during DNA replication.

Factors predicting concurrent cholangiocarcinomas associated with hepatolithiasis

BACKGROUND/AIMS

Hepatolithiasis is a risk factor for cholangiocarcinoma. However, it is difficult to detect early cholangiocarcinoma that occurs as a complication of hepatolithiasis. To identify the factors, which can be used for predicting cholangiocarcinomas in patients with hepatolithiasis, we compared the clinical characteristics of patients who had cholangiocarcinoma associated with hepatolithiasis with those of patients with hepatolithiasis only.

METHODOLOGY

Forty patients with cholangiocarcinoma associated with hepatolithiasis (group HC) and 73 patients with hepatolithiasis only (group H) were randomly selected for this study. Mean tumor size was 6.1 +/- 2.4 cm in diameter.

RESULTS

Patients of group HC were older (56.7 +/- 8.9 yr) than those of group H (49.2 +/- 12.9 yr) (p < 0.001). Weight loss was more frequent in group HC (51.5%) than in group H (5.5%) (p < 0.001) and serum alkaline phosphatase levels were higher in group HC (181 +/- 184 IU/L) than in group H (426 +/- 385 IU/L) (p < 0.001). The proportion of the patients who had hepatolithiasis in the right or both lobes of the liver was higher in group HC (72.5%) than in group H (50.6%) (p = 0.024). The optimal cutoff value of serum CEA level for cholangiocarcinoma detection was set at 4.2 ng/mL using ROC cure to give a sensitivity of 67.6% and a specificity of 90.5%. Group HC differed from group H because of its lower rates of both abdominal pain and cholangitis, longer duration of stone history, and lower serum albumin level. Factors that did not predict cholangiocarcinoma included sex ratio, white blood cell count, serum bilirubin level, and hepatic atrophy.

CONCLUSIONS

Cholangiocarcinoma should be suspected in patients with hepatolithiasis, especially when, the patient is over 40 years old, has a long history of hepatolithiasis with weight loss, a higher level of serum alkaline phosphatase, a lower level of serum albumin, a serum carcinoembryonic antigen level exceeding 4.2 ng/mL, and hepatolithiasis that is located either in the right or both lobes of the liver.

First principles calculations of the tautomers and pK(a) values of 8-oxoguanine: implications for mutagenicity and repair

8-Oxoguanine is a mutagenic oxidative damage product of guanine that has been the subject of many experimental studies. Despite numerous references to this damaged base, its precise configuration or population of configurations in equilibrium are unknown, as it can be drawn in over 100 potential neutral and ionized tautomeric forms. The structural uncertainty surrounding 8-oxoguanine complicates mechanistic studies of its mutagenicity and capacity to be recognized for repair. Experimental measurements on the tautomeric equilibria and pK(a) values of 8-oxoguanine are complicated by its insolubility in water. Therefore, we used first principles quantum mechanics (density functional theory, B3LYP, in combination with the Poisson-Boltzmann continuum-solvation model) to investigate the relative stabilities and site-specific pK(a) values of various neutral and ionized tautomers of 8-oxoguanine. We show that the major tautomer of neutral 8-oxoguanine in aqueous solution is the 6,8-diketo form 2, and that 8-oxoguanine has increased acidity at N1 relative to guanine. Our calculations on 2'-deoxyguanosine-3',5'-bisphosphate and its 8-oxo analogue support the accepted conclusion that repulsion between the O8 of 8-oxoguanine and O5' of the backbone sugar promote 8-oxoguanine:adenine pairings in the syn:anti conformation. Further, we show that the N7 proton of 8-oxoguanine is difficult to remove either through tautomerization or ionization, consistent with its involvement as an important landmark in distinguishing guanine from 8-oxoguanine. The possibility of additional structural landmarks that distinguish 8-oxoguanine from guanine, and a possible mechanism for glycosylase removal of 8-oxoguanine are discussed.

Chelators for radioimmunotherapy: I. NMR and ab initio calculation studies on 1,4,7,10-tetra(carboxyethyl)-1,4,7,10-tetraazacyclododecane (DO4Pr) and 1,4,7-tris(carboxymethyl)-10-(carboxyethyl)-1,4,7,10-tetraazacyclododecane (DO3A1Pr)

This work describes the modification of the chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N' ',N' "-tetraacetic acid (DOTA) to improve the rate of metal loading for radioimmunotherapy applications. Previous ab initio calculations predicted that the compounds 1,4,7,10-tetra(carboxyethyl)-1,4,7,10-tetraazacyclododecane (DO4Pr) and 1,4,7-tris(carboxymethyl)-10-(carboxyethyl)-1,4,7,10-tetraazacyclododecane (DO3A1Pr) have a ca. 2000-fold improvement in yttrium metal loading rates compared to those of DOTA (Jang, Y. H.; Blanco, M.; Dasgupta, S.; Keire, D. A.; Shively, J. E.; Goddard, W. A., III. J. Am. Chem. Soc. 1999, 121, 6142-6151). In this study, we report the synthesis, purification, (1)H-NMR chemical shift assignments, pK(a) values, metal loading rate measurements, and additional ab initio calculations of these two compounds. The yttrium loading rates of DO3A1Pr are approximately twice those of DOTA, at pH 4.6 and 37 degrees C. The NMR data indicates that the DO4Pr analogue forms a stable type I complex but does not form a type II complex. The new ab initio calculations performed on DO4Pr and DO3A1Pr indicate that the rate-determining step is the deprotonation of the first macrocycle amine proton, not the second proton as assumed in the previous calculations. The new calculations predict an improvement in the rate of metal loading that more closely matches the experimentally observed change in the rate.

Genetic alterations in gallbladder adenoma, dysplasia and carcinoma

Adenoma and dysplasia in the gallbladder (GB) have been reported as precancerous lesions, but the genetic evidence of this is not clearly defined. The purpose of this study was to analyze the frequencies of K-ras, p53, and p16 gene mutations, of microsatellite instability (MI) and of loss of heterozygosity (LOH) in GB cancer, dysplasia, and adenoma. Tissues from 15 GB cancers, five dysplasias around cancerous tumors, and three adenomas were collected prospectively. The mutation rates of K-ras, p53, and p16 were 20.0, 35.7, and 30.7%, respectively, in GB cancers. However, no mutations were found in dysplasia or adenoma. Reduced staining for p16 was seen in 23% of carcinomas. All of the GB carcinomas and four out of five (80%) of the dysplasias showed LOH in a minimum of one locus, but one out of three (33%) cases of adenoma displayed LOH in only one locus. All of the loci of LOH in the dysplasias, except one, showed the same patterns of allelic loss as the adjacent carcinomas. Only one dysplasia showed multiple MI. In conclusion, multiple LOH may be associated with the development of dysplasia and the malignant transformation of GB carcinoma. Gene alterations of K-ras, p53, and p16 are important steps in the malignant changes of dysplasia. However, MI seems to have only a limited role in GB cancer development.

Conformation and proton configuration of pyrimidine deoxynucleoside oxidation damage products in water

Emerging data strongly suggest that the oxidation of DNA bases can contribute to genomic instability. Structural changes to DNA, induced by base oxidation, may reduce the fidelity of DNA replication and interfere with sequence-specific DNA-protein interactions. We have examined the structures of a series of pyrimidine deoxynucleoside oxidation damage products in aqueous solution. The modified nucleosides studied include the deoxynucleoside derivatives of 5-hydroxyuracil, 5-hydroxycytosine, 5-(hydroxymethyl)uracil, 5-(hydroxymethyl)cytosine, 5-formyluracil, and 5-formylcytosine. The influence of base oxidation on ionization constants, sugar conformation, and tautomeric configuration has been determined on the basis of UV, proton, and nitrogen NMR spectra of the (15)N-enriched derivatives. The potential biological consequences of the structural perturbations resulting from base oxidation are discussed.

Adsorption of a mixture of Thiobacillus thiooxidans and Thiobacillus ferrooxidans onto copper-containing furnace dust

The Langmuir adsorption parameter X(Am) of a mixture of culture of Thiobacillus ferrooxidans and Thiobacillus thiooxidans indicates that these bacteria have preferential and competitive adsorption sites on furnace dust. The constant K(A) of the mixture significantly larger than that of each component, suggesting that a synergistic effect may occur in the binding of these bacteria to the dust.

C-reactive protein, sialic acid and adenosine deaminase levels in serum and pleural fluid from patients with pleural effusion

Laboratory analysis of pleural fluids is essential to determine underlying diseases. The authors evaluated the clinical significance of C-reactive protein (C-RP), sialic acid (SA), and adenosine deaminase (ADA) determinations in sera and pleural fluids from 37 patients with pleural effusion. (FP12)C-RP and sialic acid levels and ADA activities were higher in exudates than in transudates of pleural fluids. Serum and pleural fluid C-RP levels were high in patients with pyothorax. Determinations of serum sialic acid and the pleural fluid to serum ratio were useful for the differential diagnosis of pulmonary tuberculosis and malignancy. ADA activities of pleural fluid and serum are useful for the differentiation of malignancy from tuberculosis and nonspecific pyothorax. C-RP concentrations of pleural fluid correlated to serum levels. However, concentrations of sialic acid and ADA activities were not correlated to serum levels and only correlated to protein concentrations of pleural fluids.