Acetylcysteine for the prevention of renal outcomes in patients with diabetes mellitus undergoing coronary and peripheral vascular angiography: a substudy of the acetylcysteine for contrast-induced nephropathy trial.

BACKGROUND: Diabetes mellitus represents an independent risk factor for contrast-induced acute kidney injury. We report the results of a prespecified substudy of patients with diabetes mellitus included in the Acetylcysteine for Contrast-Induced Nephropathy Trial (ACT), the largest randomized study evaluating the effects of acetylcysteine for the prevention of contrast-induced acute kidney injury conducted to date. METHODS AND RESULTS: From the 2308 patients included in the ACT, 1395 had diabetes mellitus and were considered for the present analysis. The study drugs (acetylcysteine 1200 mg or matching placebo) were administered orally twice daily for 2 doses before and 2 doses after the procedure. The allocation was concealed (central Web-based randomization). Participants, healthcare staff, data collectors, and outcome assessors were blinded. All analysis followed the intention-to-treat principle. The incidence of contrast-induced acute kidney injury (primary end point) was 13.8% in the acetylcysteine group and 14.7% in the control group (relative risk 0.93; 95% confidence interval, 0.69-1.26; P=0.64). A combined end point of death or need for dialysis at 30 days was also similar in both the groups (2.2% and 2.1%, respectively; hazard ratio, 1.07; 95% confidence interval, 0.52-2.19; P=0.86). CONCLUSIONS: In this subanalysis, acetylcysteine did not reduce the risk of contrast-induced acute kidney injury or other clinically relevant outcomes in patients with diabetes mellitus undergoing coronary and peripheral vascular angiography. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00736866.

Energetics of tert-butoxyl addition reaction to norbornadiene: a method for estimating the pi-bond strength of a carbon-carbon double bond.

The energetics of tert-butoxyl radical addition reaction to norbornadiene was investigated by time-resolved photoacoustic calorimetry (TR-PAC). The result, together with the C-O bond dissociation enthalpy (BDE) in the addition product, allowed us to calculate the pi-bond dissociation enthalpy in norbornadiene. Quantum chemistry (QC) methods were also used to obtain several enthalpies of reaction of the addition of oxygen-centered radicals to alkenes. The pi-bond dissociation enthalpies in these molecules were calculated by a procedure similar to that used in the case of norbornadiene and were compared with the pi-BDE values obtained by the method proposed by Benson. These two different approaches yield similar values for the pi-BDEs in alkenes, indicating that the addition method proposed in the present study is a valid way to derive that quantity. The influence of strain in the pi-BDEs of cyclic alkenes was investigated and allowed us to justify the difference between the pi-BDE in norbornene and norbornadiene. Finally, the thermochemistry of the addition and abstraction reactions involving these two molecules and tert-butoxyl radical was analyzed.

Energetic differences between the five- and six-membered ring hydrocarbons: strain energies in the parent and radical molecules.

The C-H bond dissociation enthalpies (BDEs) for the five- and six-membered ring alkanes, alkenes, and dienes were investigated and discussed in terms of conventional strain energies (SEs). New determinations are reported for cyclopentane and cyclohexane by time-resolved photoacoustic calorimetry and quantum chemistry methods. The C-H BDEs for the alkenes yielding the alkyl radicals cyclopenten-4-yl and cyclohexen-4-yl and the alpha-C-H BDE in cyclopentene were also calculated. The s-homodesmotic model was used to determine SEs for both the parent molecules and the radicals. When the appropriate s-homodesmotic model is chosen, the obtained SEs are in good agreement with the ones derived from group additivity schemes. The different BDEs in the title molecules are explained by the calculated SEs in the parent molecules and their radicals: (1) BDEs leading to alkyl radicals are ca. 10 kJ mol (-1) lower in cyclopentane and cyclopentene than in cyclohexane and cyclohexene, due to a smaller eclipsing strain in the five-membered radicals relative to the parent molecules (six-membered hydrocarbons and their radicals are essentially strain free). (2) C-H BDEs in cyclopentene and cyclohexene leading to the allyl radicals are similar because cyclopenten-3-yl has almost as much strain as its parent molecule, due to a synperiplanar configuration. (3) The C-H BDE in 1,3-cyclopentadiene is 27 kJ mol (-1) higher than in 1,4-cyclohexadiene due to the stabilizing effect of the conjugated double bond in 1,3-cyclopentadiene and not to a destabilization of the cyclopentadienyl radical. The chemical insight afforded by group additivity methods in choosing the correct model for SE estimation is highlighted.

C-H bond dissociation enthalpies in norbornane. An experimental and computational study.

Gas-phase C-H bond dissociation enthalpies (BDEs) in norbornane were determined by quantum chemistry calculations and the C2-H BDE was experimentally obtained for the first time by time-resolved photoacoustic calorimetry. CBS-Q and CBS-QB3 methods were used to derive the values DH degrees (C1-H) = 449 kJ mol-1, DH degrees (C7-H) = 439 kJ mol-1, and DH degrees (C2-H) = 413 kJ mol-1. The experimental result DH degrees (C2-H) = 414.6 +/- 5.4 kJ mol-1 is in excellent agreement with the theoretical value. The trend DH degrees (C1-H) > DH degrees (C7-H) > DH degrees (C2-H) is discussed.

Energetics of the allyl group.

Aiming to improve our understanding of the stability of radicals containing the allylic moiety, carbon-hydrogen bond dissociation enthalpies (BDEs) in propene, isobutene, 1-butene, (E)-2-butene, 3-metylbut-1-ene, (E)-2-pentene, (E)-1,3-pentadiene, 1,4-pentadiene, cyclohexene, 1,3-cyclohexadiene, and 1,4-cyclohexadiene have been determined by quantum chemistry calculations. The BDEs in cyclohexene, 1,3-cyclohexadiene, and 1,4-cyclohexadiene have also been obtained by time-resolved photoacoustic calorimetry. The theoretical study involved a DFT method as well as ab initio complete basis-set approaches, including the composite CBS-Q and CBS-QB3 procedures, and basis-set extrapolated coupled-cluster calculations (CCSD(T)). By taking the C(sp3)-H BDE in propene as a reference, we have concluded that one methyl group bonded to C3 in propene (i.e., 1-butene) leads to a decrease of 12 kJ mol(-1) and that a second methyl group bonded to C3 (3-methylbut-1-ene) further decreases the BDE by 8 kJ mol(-1). When the methyl group is bonded to C2 in propene (isobutene), an increase of 7 kJ mol(-1) is observed. Finally, a methyl group bonded to C1 in propene (2-butene) has essentially no effect (-1 kJ mol(-1)). While this trend can be rationalized in terms of stabilization of the corresponding radical (through hyperconjugation and pi-delocalization), the BDE values observed for the dienes can only be understood by considering the thermodynamic stabilities of the parent compounds.

Enthalpy of formation of the cyclopentadienyl radical: photoacoustic calorimetry and ab initio studies.

The gas-phase C-H bond dissociation enthalpy (BDE) in 1,3-cyclopentadiene has been determined by time-resolved photoacoustic calorimetry (TR-PAC) as 358 +/- 7 kJ mol(-1). Theoretical results from ab initio complete basis-set approaches, including the composite CBS-Q and CBS-QB3 procedures, and basis-set extrapolated coupled-cluster calculations (CCSD(T)) are reported. The CCSD(T) prediction for the C-H BDE of 1,3-cyclopentadiene (353.3 kJ mol(-1)) is in good agreement with the TR-PAC result. On the basis of the experimental and the theoretical values obtained, we recommend 355 +/- 8 kJ mol(-1) for the C-H BDE of 1,3-cyclopentadiene and 271 +/- 8 kJ mol(-1) for the enthalpy of formation of cyclopentadienyl radical.

[Fatal case during treatment of american tegumentary leishmaniasis with sodium stibogluconate bp 88 (shandong xinhua)]. / Obito durante tratamento da leishmaniose tegumentar americana com stibogluconato de sódio bp 88 (shandong xinhua).

The authors report the occurrence of a fatal case in patient with cutaneous leishmaniasis in the municipality of Caxias, MA. Male patient, 22 years old, road sweeper, presented with an ulcer in left leg, diagnosed as cutaneous leishmaniasis and treated with sodium stibogluconate BP88 (Sb+5) (Shandong Xinhua) at a dose of 10mg/Sb+5/kg/day/20 days. After dose three he presented arthralgia, myalgia, nausea and weakness. During the therapy there was an aggravation of the symptoms with abdominal pain and irradiation into the thorax. After dose seven he presented a picture of associated dyspnea and thoracic pain of mild intensity. At dose nine there was further worsening of the picture, nevertheless the therapy was continued up to dose 11, when the patient's state deteriorated to such an extent that he was hospitalized in the intensive care unit. Exams: erythrocytes, 4.4 million; hemoglobin, 10.6%; hematocrits, 35%; white blood cells 26,400, basophiles and myelocytes (0); segmented leukocytes, 59%; lymphocytes 30%; monocytes 2%; platelets (normal); glucose, 42mg%; urea, 73mg%; creatinine, 2.4mg%; and ECG (blockade of right branch). The patient died from cardiorespiratory insufficiency. The current report underscores the need to clarify health workers regarding the use of Sb+5 and also to remind the Health Ministry to verify the quality and origin when acquiring new products.

Obito durante tratamento da leishmaniose tegumentar americana com stibogluconato de sódio bp 88® (shandong xinhua) / Fatal case during treatment of american tegumentary leishmaniasis with sodium stibogluconate bp 88® (shandong xinhua)

Os autores relatam a ocorrência de óbito em paciente portador da forma cutânea da LTA no município de Caxias-MA. Trata-se de paciente do sexo masculino, 22 anos, gari, portador de lesäo ulcerada no membro inferior (perna esquerda), diagnosticado, após encontro do parasita (Leishmania) na lesäo, tratado com stibogluconato de sódio BP88® (Shandong Xinhua) na dose de 10mg/Sb+5/kg/dia/20 dias. Após a 3ª dose apresentou dores articulares, naúseas, mal estar geral. Com a continuaçäo da medicaçäo houve agravamento do quadro com dor epigástrica e no hipocôndrio direito irradiando-se para o hemitórax homolateral. Após a 7ª dose apresentou dispnéia associado à dor torácica de leve intensidade. Na 9ª dose houve piora do quadro, mesmo assim continuou a usar o medicamento até a 11ª dose quando seu estado agravou-se. Foi internado, necessitando de tratamento intensivo. Nos exames realizados apresentou: 4,4 milhöes de eritócitos, 10,6 por cento de hemoglobina, 35 por cento de hematócrito, 26.400 de leucócitos, basófilos e mielócitos (0), 59 por cento de segmentados, 30 por cento de linfócitos, 2 por cento de monócitos, plaquetas (normais), glicose 42mg por cento, uréia 73mg por cento, creatinina (2,4mg por cento), eletrocardiograma (bloqueio de ramo direito). Veio a falecer tendo como causa do óbito, insuficiência cárdio respiratória. O relato atual mostra a necessidade de esclarecimento das equipes de saúde quanto ao uso dos Sb+5 e também lembrar o Ministério da Saúde quando da aquisiçäo de novos produtos, preocupar-se com a qualidade e procedência do mesmo