Free radical scavenging activity of Pterogyne nitens Tul. (Fabaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Re-examination of the anion derivatives of isoflavones by radical fragmentation in negative electrospray ionization tandem mass spectrometry: experimental and computational studies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Radical Scavenging Capacity of Piper arboreum and Piper tuberculatum (Piperaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Não há dente de coelho no problema da tradução radical

O trabalho consiste em uma tentativa de refutação do princípio quineano da indeterminação da tradução radical. A estrutura do argumento é a seguinte. A demonstração do princípio no texto de Quine assenta-se sobre certa concepção do processo de tradução radical. Esta concepção só se sustenta se são adotadas certas pressuposições a respeito da natureza da linguagem e dos falantes. Entretanto, se estas pressuposições são adotadas, não há razão para não se aceitarem também outras pressuposições - as quais invalidam a demonstração de Quine.

Expression of p53, Ki-67, and CD31 in the vaginal margins of radical hysterectomy in patients with stage IB carcinoma of the cervix

Objectives. This study was undertaken to evaluate the expression of p53, Ki-67, and CD31 both in the tumor and in the vaginal margins of radical hysterectomy in patients with stage IB squamous cell carcinoma of the cervix, as an attempt to use these proteins as possible markers for residual tumor in cervical cancer.Methods. Thirty patients with stage IB squamous cell carcinoma of the cervix were submitted to radical hysterectomy (study group), and thirty patients with uterine myoma were submitted to vaginal hysterectomy (control group) and were prospectively studied from November 2001 to September 2002. Tissue samples were taken from the tumor or cervix, anterior vaginal margin (AVM), and posterior vaginal margin (PVM) and were immunohistochemically evaluated by monoclonal antibodies for p53, Ki-67, and CD31. Vaginal samples in which the histological examination showed tumor involvement were excluded from the study.Results. Patient's mean age was 48.7 +/- 10.4 years (27-73 years). The clinical stage was IB1 in 22 patients (73.3%) and IB2 in eight patients (26.7%). The expressions of p53, Ki-67, and CD31 were significantly higher in the tumor than in the benign cervix (P < 0.001). Higher expressions of these markers were noted in the vaginal margins of radical hysterectomy in patients with cervical carcinoma compared to the vaginal margins of control patients. This association was demonstrated for p53 in the AVM proximal (P = 0.045), for Ki-67 in AVM proximal (P < 0.001), AVM distal (P < 0.001), PVM proximal (P = 0.009), and PVM distal (P < 0.001), and for CD31 in AVM proximal (P = 0.003) and AVM distal (P = 0.018). There was no difference in p53, Ki-67, and CD31 expression between the proximal and distal regions of the vaginal margins in patients with carcinoma of the cervix.Conclusion. The expressions of p53, Ki-67, and CD31 were significantly higher in both the histologically positive (cervical tumor) and negative (vaginal margins) tissues of patients who had undergone radical hysterectomy for cervical cancer compared to the benign control tissues. (C) 2004 Elsevier B.V. All rights reserved.

Energy-transfer mechanisms and emission quantum yields in Eu3+-based siloxane-poly(oxyethylene) nanohybrids

We report the energy-transfer mechanisms and emission quantum yield measurements of sol-gel-derived Eu3+-based nanohybrids. The matrix of these materials, classified as diureasils and termed U(2000) and U(600), includes urea cross-links between a siliceous backbone and polyether-based segments of two molecular weights, 2000 and 600, respectively. These materials are full-color emitters in which the Eu3+ (5)Do --> F-7(0-4) lines merge with the broad green-blue emission of the nanoscopic matrix's backbone. The excitation spectra show the presence of a large broad band (similar to 27000-29000 cm(-1)) undoubtedly assigned to a ligand-to-metal charge-transfer state. Emission quantum yields range from 2% to 13.0% depending on the polymer molecular weight and Eu3+ concentration. Energy transfer between the hybrid hosts and the cations arises from two different and independent processes: the charge-transfer band and energy transfer from the hybrid's emitting centers. The activation of the latter mechanisms induces a decrease in the emission quantum yields (relative to undoped nanohybrids) and permits a fine-tuning of the emission chromaticity across the Comission Internacionalle d'Eclairage diagram, e.g., (x, y) color coordinates from (0.21, 0.24) to (0.39, 0.36). Moreover, that activation depends noticeably on the ion local coordination. For the diureasils with longer polymer chains, energy transfer occurs as the Eu3+ coordination involves the carbonyl-type oxygen atoms of the urea bridges, which are located near the hybrid's host emitting centers. on the contrary, in the U(600)-based diureasils, the Eu3+ ions are coordinated to the polymer chains, and therefore, the distance between the hybrid's emitting centers and the metal ions is large enough to allow efficient energy-transfer mechanisms.

THE CATHODIC CLEAVAGE OF THE NITROBENZENESULFONYL GROUP FROM ALIPHATIC-AMINES IN N,N-DIMETHYLFORMAMIDE

The reduction of benzenesulfonyl derivatives of n-butylamine and N,N-di-n-butylamine with nitro substituents at the 2, 3 and 4 positions of the phenyl ring in N,N-dimethylformamide is reported. The N,N-di-n-butyl-4- and N-n-butyl-2-nitrobenzenesulfonamides are reduced in two cathodic steps. The first one, at about -0.90 V vs. SCE, a reversible one-electron process, gives a stable anion radical. The second reduction step at -1.70 V vs. SCE leads to cleavage of the S-N bond in good yields (> 70%). It is shown that the reduction of the N-n-butyl-3- and N-n-butyl-4-nitrobenzenesulfonamide is different, with three reduction steps. The first reduction step occurs with the formation of an unstable anion radical, which decomposes via N-H bond cleavage. The reduction of this sulfonamide anion occurs at -1.16 V vs. SCE and the third cathodic step arises at -1.70 V vs. SCE when the remaining radical anion is reduced to its dianion. The S-N bond cleavage is rapid but is always a minor process. The mechanisms of the reduction are discussed.

Genetic parameters of milk, fat, and protein yields in the first three lactations, using an animal model and restricted maximum likelihood

Milk, fat, and protein yields of Holstein cows from the States of New York and California in the United States were used to estimate (co)variances among yields in the first three lactations, using an animal model and a derivative-free restricted maximum likelihood (REML) algorithm, and to verify if yields in different lactations are the same trait. The data were split in 20 samples, 10 from each state, with means of 5463 and 5543 cows per sample from California and New York. Mean heritability estimates for milk, fat, and protein yields for California data were, respectively, 0.34, 0.35, and 0.40 for first; 0.31, 0.33, and 0.39 for second; and 0.28, 0.31, and 0.37 for third lactations. For New York data, estimates were 0.35, 0.40, and 0.34 for first; 0.34, 0.44, and 0.38 for second; and 0.32, 0.43, and 0.38 for third lactations. Means of estimates of genetic correlations between first and second, first and third, and second and third lactations for California data were 0.86, 0.77, and 0.96 for milk; 0.89, 0.84, and 0.97 for fat; and 0.90, 0.84, and 0.97 for protein yields. Mean estimates for New York data were 0.87, 0.81, and 0.97 for milk; 0.91, 0.86, and 0.98 for fat; and 0.88, 0.82, and 0.98 for protein yields. Environmental correlations varied from 0.30 to 0.50 and were larger between second and third lactations. Phenotypic correlations were similar for both states and varied from 0.52 to 0.66 for milk, fat and protein yields. These estimates are consistent with previous estimates obtained with animal models. Yields in different lactations are not statistically the same trait but for selection programs such yields can be modelled as the same trait because of the high genetic correlations.

The cathodic deprotection of the nitrobenzoyl group from phenyl nitrobenzoates in N,N-dimethylformamide

The reduction of phenyl benzoates with nitro substituents at the 2-,3- and 4-positions of the benzoates in N,N-dimethylformamide is reported. The phenyl 4- and 3-nitrobenzoate are reduced in two cathodic steps. The first one, at about -0.9 V vs. SCE, a reversible one-electron process, gives a rather stable anion radical. The second reduction step at potentials between -1.5 and -2.0 V vs. SCE leads to formation of the dianion, which decomposes giving free phenol in good yields (> 80%). on the other hand, the phenyl 2-nitrobenzoate is reduced in one cathodic step. This step occurs at -0.9 V with formation of an unstable anion radical which decomposes via C-O bond cleavage, giving phenol with a yield of ca. 80%. The mechanisms of the reduction of these compounds are discussed. (C) 1997 Elsevier B.V. S.A.

Toxicity of chronic ethanol ingestion and superoxide radical formation on seminal vesicles of rats

The toxic effects of chronic ethanol ingestion were evaluated in male adult rats for 300 days. The animals were divided into three groups: the controls received only tap water as liquid diet; the chronic ethanol ingestion group received only ethanol solution (30%) in semivoluntary research; and the withdrawal group received the same treatment as chronic ethanol-treated rats until 240 days, after which they reverted to drinking water. Chronic ethanol ingestion induced increased lipoperoxide levels and acid phosphatase activities in seminal vesicles. Cu-Zn superoxide dismutase (SOD) decreased from its basal level 70.8 +/- 3.5 to 50.4 +/- 1.6 U/mg protein at 60 days of chronic ethanol ingestion. As changes in GSH-PX activity were observed in rats after chronic ethanol ingestion, while SOD activities were decreased in these animals, it is assumed that superoxide anion elicits lipoperoxide formation and induces cell damage before being converted to hydrogen peroxide by SOD. Ethanol withdrawal induced increased SOD activity and reduced seminar vesicle damage, indicating that the toxic effects were reversible, since increased SOD activity was adequate to scavenge superoxide radical formation. Superoxide radical is an important intermediate in the toxicity of chronic ethanol ingestion. Copyright (C) 1996 Elsevier B.V. Ltd

Global yields, chemical compositions and antioxidant activities of clove basil (Ocimum gratissimum L.) extracts obtained by supercritical fluid extraction

Clove basil (Ocimum gratissimum) extracts were obtained with supercritical CO2. Clove basil was cultivated using 0, 4, 8 and 12 kg/m(2) of organic fertilizer and was harvested in four seasons: winter, spring, summer and autumn, in the Southern Hemisphere. The extracts' global yields were determined at 40C and 150 bar for samples from all cultivation conditions and harvesting seasons. For selected samples, the extracts' global yields at 40C were determined for pressures of 100, 150, 200, 250 and 300 bar. The extracts were analyzed by gas chromatography-flame ionization detector. Antioxidant activity (AA) was assessed using the coupled reaction of beta-caroteneand linolenic acid. The extracts' global yields varied from 0.91 to 1.79% (dry basis), and the AAs varied from 62 to 84% compared with the control beta-carotene. Eugenol and beta-selinene were the major compounds. The relative proportion of eugenol varied from 35 to 60%, while the content of beta-selinene remained approximately constant (11.5-14.1%, area). The other substances quantified in the extracts were 1,8 cineole, trans-caryophyllene and alpha-selinene.

New chemical evidence for the ability to generate radical molecular ions of polyenes from ESI and HR-MALDI mass spectrometry

We report here new chemical evidence for the generation of radical molecular ions of compounds with a conjugated pi-system (polyene) in ESI and HR-MALDI mass spectrometry. The oxidation potential of the neutral polyenes was calculated by cyclic-voltammetry and the results compared with those previously published for other complex conjugated compounds that have also been shown to form M.+ in ESI-MS. This study clearly demonstrates the correlation between the oxidation potential and the formation of the M.+ for the polyenes studied.

SUPEROXIDE RADICAL AND TOXICITY OF ENVIRONMENTAL NICKEL EXPOSURE

Three nickel compounds were tested for pancreatic, hepatic and osteogenic damage in rats by a single i.m. injection Ni++ (7 mg kg(-1)). The nickel induced biochemical alterations included significantly increased levels of serum alkaline phosphatase in rats with NiS (75%) and NiO (50%). Amylase and aspartate transaminase were also increased, and lipoperoxide was increased in rats with NiO (5.6-fold) and NiS (3.4-fold). No serum changes were observed with NiCl2. Daily injection of Cu-Zn superoxide dismutase (SOD) conjugated with polyethylene glycol prevented the serum level changes, indicating that superoxide radical is an important intermediate in toxicity of nickel insoluble compounds.