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ABSTRACT: Pre-implantation genetic diagnosis (PGD) is an assisted reproductive technology procedure which provides parents with the option of conducting genetic analyses to determine if a mutation is present in an embryo. Though studies have discussed perceptions of PGD from a general population, couples or high-risk women, no studies to date have specifically examined PGD usage among men. This study sought to explore perceptions and attitudes towards PGD among males who either carry a BRCA mutation or have a partner or first degree relative with a BRCA mutation.
A cross-sectional survey was conducted among 228 men visiting the Facing Our Risk of Cancer Empowered or Craigslist website. Eligibility criteria included men who self-reported they had been tested for a BRCA mutation or had a partner or first degree relative tested for a BRCA mutation. A 41-item survey assessed socio-demographic, clinical characteristics, PGD knowledge and attitudinal factors and consideration of the use of PGD. Differences in proportions of subgroups were tested using the Monte Carlo exact test for categorical data. A multiple logistic regression model was then built through a backward elimination procedure.
Although 80% of men reported being previously unfamiliar with PGD, after learning the definition of PGD, 34% of the 228 respondents then said they would 'ever consider the use of PGD'. Respondents who thought of PGD only in terms of 'health and safety' were almost three times more likely (OR = 2.82; 95% 1.19-6.71) to 'ever consider the use of PGD' compared with respondents who thought of PGD in terms of both 'health and safety', and 'religion and morality'.
As with other anonymous web-based surveys, we cannot verify clinical characteristics that may impact consideration of PGD use. Our findings indicate high-risk men need more information about PGD and may benefit from educational materials to assist them in reproductive decision-making.
Human Reproduction 10/2010; 25(10):2543-50. · 4.47 Impact Factor
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ABSTRACT: The reaction of Ru(II)(acac)2(py-imH) (Ru(II)imH) with TEMPO(*) (2,2,6,6-tetramethylpiperidine-1-oxyl radical) in MeCN quantitatively gives Ru(III)(acac)2(py-im) (Ru(III)im) and the hydroxylamine TEMPO-H by transfer of H(*) (H(+) + e(-)) (acac = 2,4-pentanedionato, py-imH = 2-(2'-pyridyl)imidazole). Kinetic measurements of this reaction by UV-vis stopped-flow techniques indicate a bimolecular rate constant k(3H) = 1400 +/- 100 M(-1) s(-1) at 298 K. The reaction proceeds via a concerted hydrogen atom transfer (HAT) mechanism, as shown by ruling out the stepwise pathways of initial proton or electron transfer due to their very unfavorable thermochemistry (Delta G(o)). Deuterium transfer from Ru(II)(acac)2(py-imD) (Ru(II)imD) to TEMPO(*) is surprisingly much slower at k(3D) = 60 +/- 7 M(-1) s(-1), with k(3H)/k(3D) = 23 +/- 3 at 298 K. Temperature-dependent measurements of this deuterium kinetic isotope effect (KIE) show a large difference between the apparent activation energies, E(a3D) - E(a3H) = 1.9 +/- 0.8 kcal mol(-1). The large k(3H)/k(3D) and DeltaE(a) values appear to be greater than the semiclassical limits and thus suggest a tunneling mechanism. The self-exchange HAT reaction between Ru(II)imH and Ru(III)im, measured by (1)H NMR line broadening, occurs with k(4H) = (3.2 +/- 0.3) x 10(5) M(-1) s(-1) at 298 K and k(4H)/k(4D) = 1.5 +/- 0.2. Despite the small KIE, tunneling is suggested by the ratio of Arrhenius pre-exponential factors, log(A(4H)/A(4D)) = -0.5 +/- 0.3. These data provide a test of the applicability of the Marcus cross relation for H and D transfers, over a range of temperatures, for a reaction that involves substantial tunneling. The cross relation calculates rate constants for Ru(II)imH(D) + TEMPO(*) that are greater than those observed: k(3H,calc)/k(3H) = 31 +/- 4 and k(3D,calc)/k(3D) = 140 +/- 20 at 298 K. In these rate constants and in the activation parameters, there is a better agreement with the Marcus cross relation for H than for D transfer, despite the greater prevalence of tunneling for H. The cross relation does not explicitly include tunneling, so close agreement should not be expected. In light of these results, the strengths and weaknesses of applying the cross relation to HAT reactions are discussed.
Journal of the American Chemical Society 11/2008; 130(44):14745-54. · 9.91 Impact Factor
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Inorganic Chemistry 05/2007; · 4.60 Impact Factor
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ABSTRACT: Rhenium-oxo-fluoride complexes are readily prepared using hydrotris(3,5-dimethyl-1-pyrazolyl)borate [HB(3,5-Me(2)pz)(3)(-), Tp] as a supporting ligand. For instance, treatment of TpRe(O)(OH)Cl with concentrated aqueous HF cleanly forms the chloro-fluoride complex TpRe(O)(F)Cl. Related fluoro-iodide, fluoro-triflate, and difluoride complexes are also described. In contrast, a variety of reactions of analogous compounds with the unsubstituted hydrotris(1-pyrazolyl)borate ligand [HB(pz)(3)(-), Tp] have failed to produce fluoro complexes. Extended refluxing of TpRe(O)I(2) with an excess of NaF in acetonitrile in the air gives a modest yield of an unusual rhenium &mgr;-pyrazolyl &mgr;-oxo dimer, {[kappa(2)-H(F)Bpz(2)]Re(O)}(2)(&mgr;-pz)(2)(&mgr;-O) (5) (pz = pyrazolyl). The X-ray crystal structure of 5 shows that one pyrazolyl of each Tp ligand has been substituted for fluoride. The different reactivity of the Tp and Tp complexes is apparently due to the greater steric protection of the boron afforded by the Tp() ligand. Crystallographic data for 5: monoclinic; space group Cc; a = 19.103(4) Å, b = 10.482(2) Å, c = 14.240(3) Å, beta = 114.82(3) degrees; Z = 4; R = 3.73%, R(w) (observed data) = 4.73%; GOF = 1.20.
Inorganic Chemistry 08/1999; 38(14):3309-3312. · 4.60 Impact Factor
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Inorganic Chemistry 07/1999; 38(12):2760-2761. · 4.60 Impact Factor
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ABSTRACT: Reaction of rhenium(V)-oxo-halo-triflate complexes (HB(pz)(3))ReO(X)OTf (1, X = Cl, Br, I) with 1 equiv of pyridine N-oxide forms rare d(1) rhenium(VI) cis-dioxo compounds (HB(pz)(3))ReO(2)X (2, X = Cl, Br, I). This reaction likely occurs by initial formation of the d(0) rhenium(VII) dioxo cation (HB(pz)(3))ReO(2)X(+) by oxygen atom transfer, followed by a rapid one electron reduction. The chloride derivative 2a has been characterized by an X-ray crystal structure. The d(1) dioxo compounds are fairly stable, disproportionating slowly to (HB(pz)(3))ReO(3) and (HB(pz)(3))ReOX(2). Electrochemical oxidations of (HB(pz)(3))ReO(2)X to Re(VII) cations are reversible and are at remarkably high potentials (E(1/2) = 0.93 V vs Cp(2)Fe(+/0) in acetonitrile for 2a). When Me(2)SO is used as the oxidant instead of pyridine N-oxide, the Re(V) adducts [(HB(pz)(3))ReO(X)(OSMe(2))][OTf] (5) are formed by triflate displacement. These complexes reversibly lose SMe(2) (for 5a, k = 3.3(4) x 10(-)(6) s(-)(1) at 297 K in CD(2)Cl(2)), as shown by isotope exchange experiments. The intermediate Re(VII) cations (HB(pz)(3))ReO(2)X(+) oxidize Me(2)S much faster than Me(2)SO, indicating that they are highly electrophilic oxygen atom transfer reagents. Complexes 2, however, are relatively unreactive materials. Crystallographic data for 2a: C(9)H(10)BClN(6)O(2)Re; monoclinic, Cc; a = 14.716(3), b = 7.651(2), c = 13.232(3) Å; beta = 110.61(3) degrees; Z = 4.
Inorganic Chemistry 03/1998; 37(3):445-453. · 4.60 Impact Factor
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ABSTRACT: Chromyl chloride (CrO(2)Cl(2)) reacts with neat isopropylcyclopropane at 65 degrees C to give a dark precipitate along with at least 20 organic products. Both cyclopropyl products and ring-opened products are observed: 2-cyclopropyl-2-chloropropane (1, 0.4% yield based on chromium), 2-cyclopropyl-2-propanol (2, 0.2%), 5-chloro-2-methyl-2-pentene (3, 0.3%), and 4-methyl-3-penten-1-ol (4, 0.5%) as well as other ring-opened products. Authentic samples of 1-4 were synthesized, and their GC and GC/MS data were compared with the reaction mixture. Other organic products (5-10) were tentatively assigned by GC/MS on the basis of their m/z and fragmentation patterns. The ratio of (1 + 2) vs (3 + 4) increases by a factor of 2 when the initial concentration of CrO(2)Cl(2) increases from 0.3 to 1.12 M. The reaction was also carried out in the gas phase, and essentially all the products from the liquid phase reaction were observed. The products are explained by a mechanism involving initial hydrogen atom abstraction from the substrate. The resulting dimethylcyclopropylcarbinyl radical can either be trapped by CrO(2)Cl(2) (to form 1 and 2) or ring-open to give 4-methyl-3-pentenyl radical, which reacts with CrO(2)Cl(2) to form 3 and 4 as well as further oxidized products. The oxidation of isopropylcyclopropane by MnO(4)(-) in pyridine was also examined. Acetone, an expected ring-opened product, was the only product observed by our analytical techniques. Me(2)C(18)O is produced from (18)O-labeled MnO(4)(-). These results suggest that the reactions of CrO(2)Cl(2) and MnO(4)(-) with isopropylcyclopropane proceed by hydrogen atom transfer to form organic radical intermediates.
The Journal of Organic Chemistry 07/1997; 62(13):4248-4252. · 4.45 Impact Factor
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ABSTRACT: Oxidations of arylalkanes by (n)()Bu(4)NMnO(4) have been studied in toluene solvent: toluene, ethylbenzene, diphenylmethane, triphenylmethane, 9,10-dihydroanthracene, xanthene, and fluorene. Toluene is oxidized to benzoic acid and a small amount of benzaldehyde; other substrates give oxygenated and/or dehydrogenated products. The manganese product of all of the reactions is colloidal MnO(2). The kinetics of the reactions, monitored by UV/vis spectrometry, show that the initial reactions are first order in the concentrations of both (n)()Bu(4)NMnO(4) and substrate. No induction periods are observed. The same rate constants for toluene oxidation are observed in neat toluene and in o-dichlorobenzene solvent, within experimental errors. The presence of O(2) increases the rate of (n)()Bu(4)NMnO(4) disappearance. The reactions of toluene and dihydroanthracene exhibit primary isotope effects: k(C)()7(H)()8/k(C)()7(D)()8 = 6 (+/-1) at 45 degrees C and k(C)()14(H)()12/k(C)()14(D)()12 = 3.0 (+/-0.6) at 25 degrees C. The rates of oxidation of substituted toluenes show only small substituent effects. In the reactions of dihydroanthracene and fluorene, the MnO(2) product is consumed in a subsequent reaction that appears to form a charge-transfer complex. The rate-limiting step in all of the reactions is hydrogen atom transfer from the substrate to a permanganate oxo group. The enthalpies of activation for the different substrates are directly proportional to the DeltaH degrees for the hydrogen atom transfer step, as is typical of organic radical reactions. The ability of permanganate to abstract a hydrogen atom is explained on the basis of its ability to form an 80 +/- 3 kcal/mol bond to H(*), as calculated from a thermochemical cycle. (This bond strength is slightly lower than given in earlier calculations.) Rates of H(*) abstraction by (n)()Bu(4)NMnO(4) correlate with rates of abstraction by oxygen radicals.
Inorganic Chemistry 06/1997; 36(10):2069-2078. · 4.60 Impact Factor
