Patient and surgeon characteristics associated with increased use of contralateral prophylactic mastectomy in patients with breast cancer.

Introduction: Patients with unilateral breast cancer have an increased risk of developing contralateral breast cancer. A recent population-based study demonstrated that the proportion of patients with unilateral breast cancer in the United States who underwent contralateral prophylactic mastectomy (CPM) has increased by 150% in recent years. The current study evaluated patients who underwent breast cancer surgery in a metropolitan-based hospital system to determine factors associated with CPM.

Averaging semiempirical NMR chemical shifts: dynamic effects on the subpicosecond time scale.

The variation of the (1)H and (13)C NMR chemical shifts of heptapeptide ATWLPPR was investigated during a hybrid quantum mechanical (QM)/molecular mechanical (MM = CHARMM) molecular dynamics simulation of the peptide in aqueous solvent. The semiempirical method OM3 was used as the QM method, and the effect of augmenting the OM3 Hamiltonian with an empirical dispersion term (OM3-D) was also explored. The semiempirical MNDO method was used to calculate the chemical shifts of snapshots taken at 50 fs intervals during the 100 ps simulation.

Ruthenium based catalysts for olefin hydrosilylation: dichloro(p-cymene)ruthenium and related complexes.

We report our third and final investigation into the use of ruthenium based compounds for catalyzing the hydrosilylation of methylvinyldimethoxysilane with methyldimethoxysilane. The catalytic mechanism of dichloro(p-cymene)ruthenium(II) (B1) is examined and compared to that of previously studied, less active catalysts. Density functional theory (DFT) has been applied to explore the possibility of fine-tuning the catalytic ability of B1.

Risk factors associated with fibular fracture after tibial plateau leveling osteotomy.

Objective: To determine the incidence of, and risk factors for, fibular fracture after tibial plateau leveling osteotomy (TPLO) in dogs.

Study Design: Case series.

Sample Population: TPLO (n=168) on 142 dogs.

Bisphenol A at low nanomolar doses confers chemoresistance in estrogen receptor-alpha-positive and -negative breast cancer cells.

Background: Resistance to chemotherapy is a major problem facing breast cancer patients, and identifying potential contributors to chemoresistance is a critical area of research. Bisphenol A (BPA) has long been suspected to promote carcinogenesis, but the high doses of BPA used in many studies generated conflicting results. In addition, the mechanism by which BPA exerts its biological actions is unclear.

Feasibility of single-voxel MRS measurement of apparent diffusion coefficient of water in breast tumors.

We report initial results with single voxel spectroscopy (SVS) using diffusion weighting and localization by adiabatic selective refocusing (LASER) in breast tumors to measure the apparent diffusion coefficient of water (ADCw). This is a quick (30 s) and relatively easy method to implement compared with image-based diffusion measurements, and is insensitive to lipid signal contamination. The ADCw and concentration of total choline containing compounds [tCho] were evaluated for associations with each other and final pathologic diagnosis in 25 subjects.

Increasing rates of contralateral prophylactic mastectomy among patients with ductal carcinoma in situ.

Purpose: Some women with unilateral ductal carcinoma in situ (DCIS) undergo contralateral prophylactic mastectomy (CPM) to prevent cancer in the opposite breast. The use and trends of CPM for DCIS in the United States have not previously been reported.

Methods: We used the Surveillance, Epidemiology, and End Results database to analyze the initial treatment (within 6 months) of patients with unilateral DCIS diagnosed from 1998 through 2005.

A critical analysis of the surgical management of early-stage gallbladder cancer in the United States.

Background: Radical resection is recommended for selected patients with gallbladder (GB) cancer. We sought to determine whether radical resection improves survival for patients with early-stage cancer and to evaluate surgeon compliance with current treatment recommendations.

Patients And Methods: Patients with stage 0, I, or II GB cancer who underwent surgical resection were identified from the Surveillance, Epidemiology, and End Results (SEER) tumor registry from 1988 through 2004.

Hydrotrioxides rather than cyclic tetraoxides (tetraoxolanes) as the primary reaction intermediates in the low-temperature ozonation of aldehydes. The case of benzaldehyde.

We demonstrate in this work by theory and experiment that benzaldehyde hydrotrioxide (PhC(O)OOOH), the intermediate most likely formed in the low-temperature ozonation of benzaldehyde, is too unstable to be detected by NMR (1H, 13C, and 17O) spectroscopy in various organic solvents at temperatures > or = -80 degrees C and that its previous detection must have been erroneous. Several plausible mechanisms for the formation of this polyoxide were explored by using density functional theory. We found that the formation of the hydrotrioxide involves the facile 1,3-dipolar insertion of ozone into the C-H bond (deltaH(double dagger) = 11.

The electronic structure of iron corroles: a combined experimental and quantum chemical study.

There is a longstanding debate in the literature on the electronic structure of chloroiron corroles, especially for those containing the highly electron-withdrawing meso-tris(pentafluorophenyl)corrole (TPFC) ligand. Two alternative electronic structures were proposed for this and the related [FeCl(tdcc)] (TDCC=meso-tris(2,6-dichlorophenyl)corrole) complex, namely a high-valent ferryl species chelated by a trianionic corrolato ligand ([Fe(IV)(Cor)(3-)](+)) or an intermediate-spin (IS) ferric ion that is antiferromagnetically coupled to a dianionic pi-radical corrole ([Fe(III)(Cor)(.2-)](+)) yielding an overall triplet ground state.

An efficient methyltrioxorhenium(VII)-catalyzed transformation of hydrotrioxides (ROOOH) into dihydrogen trioxide (HOOOH).

Dihydrogen trioxide (HOOOH) is formed nearly quantitatively in the low-temperature (-70 degrees C) methyltrioxorhenium(VII) (MTO)-catalyzed transformation of silyl hydrotrioxides (R3SiOOOH), and some acetal hydrotrioxides, in various solvents, as confirmed by 1H, and 17O NMR spectroscopy. The calculated energetics (B3LYP) for the catalytic cycle, using H3SiOOOH as a model system, is consistent with the experimentally observed activation energy (9.5 +/- 2.

Dihydrogen trioxide clusters, (HOOOH)n (n = 2-4), and the hydrogen-bonded complexes of HOOOH with acetone and dimethyl ether: implications for the decomposition of HOOOH.

Hydrogen-bonded gas-phase molecular clusters of dihydrogen trioxide (HOOOH) have been investigated using DFT (B3LYP/6-311++G(3df,3pd)) and MP2/6-311++G(3df,3pd) methods. The binding energies, vibrational frequencies, and dipole moments for the various dimer, trimer, and tetramer structures, in which HOOOH acts as a proton donor as well as an acceptor, are reported. The stronger binding interaction in the HOOOH dimer, as compared to that in the analogous cyclic structure of the HOOH dimer, indicates that dihydrogen trioxide is a stronger acid than hydrogen peroxide.

OMx-D: semiempirical methods with orthogonalization and dispersion corrections. Implementation and biochemical application.

The semiempirical methods of the OMx family (orthogonalization models OM1, OM2, and OM3) are known to describe biochemical systems more accurately than standard semiempirical approaches such as AM1. We investigate the benefits of augmenting these methods with an empirical dispersion term (OMx-D) taken from recent density functional work, without modifying the standard OMx parameters. Significant improvements are achieved for non-covalent interactions, with mean unsigned errors of 1.

Design of a new warhead for the natural enediyne dynemicin A. An increase of biological activity.

A concept for designing nontoxic enediyne-based antitumor drugs that was previously suggested (J. Am. Chem.

Exposure-response relationships for oxaliplatin-treated colon cancer cells.

Data are lacking for an optimal infusion length for oxaliplatin administered intraperitoneally. Our objectives were to establish the roles of hyperthermia and an effective length of oxaliplatin treatment in maximizing antitumor activity. SW620 cells were treated for 0.

Contralateral prophylactic mastectomy for patients with unilateral breast cancer.

Patients with unilateral breast cancer are at increased risk of developing a second cancer in the contralateral breast. Some women choose contralateral prophylactic mastectomy (CPM) to prevent cancer in the contralateral breast. Several studies have demonstrated that CPM significantly decreases the occurrence of contralateral breast cancer.

Factors influencing the number of sentinel lymph nodes identified in patients with breast cancer.

Background: Although the sentinel lymph node (SLN) is defined as the first node draining a tumor, multiple nodes are often identified. Few SLNs are required for adequate staging; removal of more may be unnecessary. The objective of this study was to determine factors influencing the number of SLN identified.

Increasing use of contralateral prophylactic mastectomy for breast cancer patients: a trend toward more aggressive surgical treatment.

Purpose: Many patients with unilateral breast cancer choose contralateral prophylactic mastectomy to prevent cancer in the opposite breast. The purpose of our study was to determine the use and trends of contralateral prophylactic mastectomy in the United States.

Patients And Methods: We used the Surveillance, Epidemiology and End Results database to review the treatment of patients with unilateral breast cancer diagnosed from 1998 through 2003.

The reactivity of calicheamicin gamma(1)(I) in the minor groove of DNA: the decisive role of the environment.

Triggering and Bergman cyclization of calicheamicin gamma(1) (I) outside and inside the minor groove of the duplex 9mer-B-DNA sequence d(CACTCCTGG).d(CCAGGAGTG) were investigated by using density functional theory and molecular mechanics (DFT and MM) descriptions in which the ligand is completely described at the DFT and the receptor at the MM level. The calculated docking energy of calicheamicin gamma(1) (I) (-12.

A QM/MM study of the Bergman reaction of dynemicin A in the minor groove of DNA.

The Bergman cyclization of the natural enediyne dynemicin A in its triggered form (2) bound to the minor groove of DNA is compared with the corresponding reaction of its open isomer (4) utilizing QM/MM methodology. The two isomers are typical representatives of 10-membered cyclic (2) and acyclic (4) enediynes, which possess significantly different barriers for the Bergman reaction in the gas phase (2, 20.4 kcal/mol; 4, 31.

Substrate orientation in 4-oxalocrotonate tautomerase and its effect on QM/MM energy profiles.

The tautomerization of 2-oxo-4E-hexendioate by 4-oxalocrotonate tautomerase has been studied by quantum mechanical/molecular mechanical (QM/MM) methods using three models, A-C, with different substrate orientations. The computed QM/MM energy profiles are rather different. Various energy partitioning analyses indicate the origin of these differences and the role of the active site residues for different substrate orientations.

Preoperative staging and postoperative surveillance for gastric cancer.

Physicians must consider multiple factors when determining the most appropriate preoperative imaging strategy for gastric cancer. Health care resources are not unlimited, and the use of multiple expensive imaging techniques that do not alter treatment decisions is not recommended. With this in mind, EGD and CT scan alone should form the basis for preoperative evaluation, with further imaging considered only in selected cases.