Acanthoscurrin Fragment 101-132: Total Synthesis at 60 degrees C of a Novel Difficult Sequence

Glycine-rich proteins (GRP), serve a variety of biological functions. Acanthoscurrin is an antimicrobial GRP isolated front hemocytes-of the Brazilian spider Acanthoscurria gomesiana. Aiming to contribute to the knowledge of the secondary structure and stepwise solid-phase synthesis of GRPs` glycine-rich domains, we attempted to prepare G(101)GGLGGGRGGGYG(113) GGGGYGGGYG(123)GGy(126)GGGKYK(132)-NH(2), acanthoscurrin C-terminal amidated fragment. Although a theoretical prediction did not indicate high aggregation potential for this peptide, repetitive incomplete aminoacylations were observed after incorporating Tyr(126) to the growing peptide-MBHA resin (Boc chemistry) at 60 degrees C. The problem was not solved by varying the coupling reagents or solvents, adding chaotropic salts to the reaction media or changing the resin/chemistry (Rink amide resin/Fmoc chemistry). Some improvement was mode when CLEAR amide resin (Fmoc chemistry) was 32 used, as it allowed for obtaining fragment (G(113)-K(132) NIR-FT-Raman spectra collected for samples of the growing peptide-MBHA, -Rink amide resin and -CLEAR amide resin revealed the presence of beta-sheet structures. Only the combination of CLEAR-amide resin, 60 degrees C, Fmoc-(Fmoc-Hmb)Gly-OH and LiCl (the last two used alternately) was able to inhibit the phenomenon, as proven by NIR-FT-Raman analysis of the growing peptide-resin, allowing the total synthesis of desired 132 fragment Gly(101)-K(132). In summary, this work describes a new difficult sequence, contributes to understanding stepwise solid-phase synthesis of this type of peptide and shows that, at least while protected and linked to a resin, this GRPs glycine-rich motif presents all early tendency to assume beta-sheet structures. (c) 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 65-75, 2009.

Comparison of adsorbent films obtained by plasma polymerization of oxygenated organic compounds

Thin films obtained by plasma polymerization of ethyl ether, methyl or ethyl acetate, acetaldehyde, acetone and 2-propanol were compared. Infrared spectroscopy (FFIR), resistance to chemicals, contact angle measurements, X-ray photoelectron spectroscopy (XPS), optical and scanning electron microscopy (SEM), and quartz crystal microbalance (QCM) were carried out. For all films FTIR showed high intensity for polar bonds yet the films are not resistant to polar solvents. Contact angle measurements revealed hydrophilic and organophilic surfaces and XPS pointed out a high proportion of oxygenated bonds. All films showed good step coverage and peeling was significant only with acetone and 2-propanol. All films are adsorbent for organic compounds in a large scale of polarity but acetaldehyde and 2-propanol act like a selective membrane. Also, deposition of these films on hydrophobic substrates leads to island formation. A possible model to explain the results must consider the hydrogen bridge formation on 2-propanol and acetaldehyde films. Ethyl ether, ethyl and methyl acetate showed good characteristics for development of sensor and sample pretreatment using miniaturized devices. (C) 2007 Elsevier B.V. All rights reserved.

Corrosion resistant and adsorbent plasma polymerized thin film

Adsorbent and corrosion resistant films are useful for sensor development. Therefore, the aim of this work is the production and characterization of plasma polymerized fluorinated organic ether thin films for sensor development. The polymerized reactant was methyl nonafluoro(iso)butyl ether. Infrared Spectroscopy showed fluorinated species and eventually CO but CH(n) is a minor species. Contact angle measurements indicated that the film is hydrophobic and organophilic but oleophobic. Optical microscopy reveals not only a good adherence on metals and acrylic but also resistance for organic solvents, acid and basic aqueous solution exposure. Double layer and intermixing are possible and might lead to island formation. Quartz Crystal Microbalance showed that 2-propanol permeates the film but there is no sensitivity to n-hexane. The microreactor manufactured using a 73 cm long microchannel can retain approximately 9 X 10(-4) g/cm(2) of 2-propanol in vapor phase. Therefore, the film is a good candidate for preconcentration of volatile organic compounds even in corrosive environment. (C) 2009 Elsevier B.V. All rights reserved.

Rapid Determination of Water-Soluble and Fat-Soluble Vitamins in Commercial Formulations by MEEKC

Microemulsion electrokinetic capillary chromatography has been successfully applied to the separation and determination of water-soluble vitamins (thiamine hydrochloride, riboflavin, niacin, pyridoxine hydrochloride, folic acid, cobalamin, ascorbic acid) and a fat-soluble vitamin (alpha-tocopherol acetate). The optimal microemulsion buffer contained sodium dodecylsulfate (SDS) as surfactant, butan-1-ol as the co-surfactant, ethyl acetate as the oil and pH 9.2 tetraborate buffer, modified with 15% (v/v) 2-propanol. UV detection at 214 nm gave adequate sensitivity without interference from sample excipients. Under the optimized conditions, the vitamins were baseline separated in less than 7 min. Analytical curves of peak area versus concentration presented coefficients of determination (R (2) ) > 0.99, acceptable limits of quantification between 8.40 and 16.23 mu g mL(-1) were obtained. Vitamin levels in liquid formulation were quantified with intra-day precision better than 0.99% RSD for migration time and 1.19% RSD for peak area ratio. Recoveries ranged between 98.7 and 101.7%. The method was considered appropriate for rapid and routine analysis.

Hollow fiber-based liquid-phase microextraction (HF-LPME) of isradipine and its main metabolite followed by chiral HPLC analysis: application to an in vitro biotransformation study

An enantioselective liquid chromatographic method using two-phase hollow fiber liquid-phase microextraction (HF-LPME-HPLC) was developed for the determination of isradipine (ISR) enantiomers and its main metabolite (pyridine derivative of isradipine, PDI) in microsomal fractions isolated from rat liver. The analytes were extracted from 1 mL of microsomal medium using a two-phase HF-LPME procedure with hexyl acetate as the acceptor phase, 30 min of extraction, and sample agitation at 1,500 rpm. For the first time, ISR enantiomers and PDI were resolved. For this separation, a ChiralpakA (R) AD column with hexane/2-propanol/ethanol (94:04:02, v/v/v) as the mobile phase at a flow rate of 1.5 mL min(-1) was used. The column was kept at 23 A +/- 2 A degrees C. The drug and metabolite detection was performed at 325 nm and the internal standard oxybutynin was detected at 225 nm. The recoveries were 23% for PDI and 19% for each ISR enantiomer. The method presented quantification limits (LOQ) of 50 ng mL(-1) and was linear over the concentration range of 50-5,000 and 50-2,500 ng mL(-1) for PDI and each ISR enantiomer, respectively. The validated method was employed to an in vitro biotransformation study of ISR using rat liver microsomal fraction showing that (+)-(S)-ISR is preferentially biotransformed.

Enantiomeric resolution of (+/-)-licarin A by high-performance liquid-chromatography using a chiral stationary phase

(+/-)-Licarin A (1), a neolignan obtained by the oxidative coupling reaction of isoeugenol, had in this study its enantiomers resolved. A novel, quick and efficient enantiomeric resolution of 1 was directly performed by chiral high-performance liquid chromatography (HPLC-PDA) protocol (CHIRALPACK (R) AD column; 9:1 (v/v) n-hexane:2-propanol; 1.0 mL/min). This method provided a chromatogram profile with a well-resolved peak separation. After isolation of each enantiomer with ee >99.9%, they were analysed in a polarimeter. Compound 2, which showed a retention time (t(r)) of 12.13 min, was the (+)-enantiomer and compound 3 (t(r) =18.90 min) was the (-)-enantiomer. (C) 2011 Elsevier B.V. All rights reserved.

Nanostructured copper thin film used for catalysis

Catalytic properties of copper thin films deposited in small channels and cavities were tested using Raman microscopy and mass spectroscopy (MS) techniques, mainly. The catalytic surface conditions were addressed visually and chemically by optical microscopy and X-ray photoelectron spectroscopy (XPS), respectively. The experimental conditions of present work induced copper oxidation; eventually a number of carbon species and graphite remained on the catalytic surface. Quartz crystal microbalance and mass spectroscopy data support both adsorption and catalysis phenomena. MS showed CO2 formation during n-hexane heating process but not to 2-propanol, probably due to redox reactions. XPS of copper surface present in the cavity after catalysis tests detected Cu2O and a range of possible carbon species. The adsorption and catalytic performance of copper films deposited in cavities and microchannels were quite similar. A simple miniaturized device for microanalysis was proposed. (C) 2007 Elsevier B.V. All rights reserved.

Catalytic hydrodechlorination of chlorobenzene over supported palladium catalyst in buffered medium

The catalytic hydrodechlorination (HDC) reaction, which is an attractive abatement process for chlorinated organic wastes, was studied over a magnetically recoverable supported Pd(0) catalyst. We investigated the most favorable reaction conditions under which to obtain the highest substrate conversion rates while preserving the catalyst properties and morphology. Sodium hydroxide, triethylamine and buffered solutions were used as proton scavengers in the HDC of chlorobenzene under mild conditions. It was observed that sodium hydroxide caused corrosion of the silica support, triethylamine in 2-propanol preserved the morphology of the catalyst which could be recycled for up to five successive H DC reactions, and aqueous buffer solutions preserved the catalyst morphology and the catalytic activity for up to four successive HDC reactions. The use of buffer solutions to neutralize the HCl formed during the HDC reaction is an interesting, less aggressive, alternative approach to HDC reactions. (C) 2010 Elsevier B.V. All rights reserved.

gamma-zein secondary structure in solution by circular dichroism

The proline-rich N-terminal domain of gamma-zein has been reported in relevant process, which include its ability to cross the cell membranes. Evidences indicate that synthetic hexapeptide (PPPVHL), naturally found in N-terminal portion of gamma-zein, can adopt the polyproline II (PPII) conformation in aqueous solution. The secondary structure of gamma-zein in maize protein bodies had been analyzed by solid state Fourier transform infrared and nuclear magnetic resonance spectroscopies. However, it was not possible to measure PPII content in physiological environment since the beta-sheet and PPII signals overlap in both solid state techniques. Here, the secondary structure of gamma-zein has been analyzed by circular dichroism in SDS aqueous solution with and without ditiothreitol (DTT), and in 60% of 2-propanol and water with DTT The results show that gamma-zein has high helical content in all solutions. The PPII conformation was present at about 7% only in water/DTT solution. (c) 2007 Wiley Periodicals, Inc.

Short-Term effect of COX-2 selective inhibitor as an adjunct for the treatment of periodontal disease: a clinical double-blind study in humans

Adjunctive therapeutic strategies that modulate the inflammatory mediators can play a significant role in periodontal therapy. In this double-blind, placebo-controlled study, 60 subjects diagnosed as periodontitis patients were evaluated for 28 days after periodontal treatment combined with selective cyclooxygenase-2 (COX-2) inhibitor. The experimental group received scaling and root planning (SRP) combined with the Loxoprofen antiinflammatory drug (SRP+Loxoprofen). The control group received SRP combined with placebo (SRP+placebo). Plaque index (PI), probing pocket depth (PD) and bleeding on probing (BOP) were monitored with an electronic probe at baseline and after 14 and 28 days. Both groups displayed clinical improvement in PD, PI and BOP. They also showed statistically similar values (p>0.05) of PD reduction on day 14 (0.4 mm) and on day 28 (0.6 mm). At the baseline, few deeper sites (>7 mm) from SRP+Loxoprofen group were responsible and most PD reduction was observed after 14 days (p<0.05). The percentage of remaining deep pockets (>7 mm) after 14 days in the SRP+Loxoprofen group was significantly lower (p<0.05) than in the SRP+placebo group. Loxoprofen presents potential effect as an adjunct of periodontal disease treatment, but long-term clinical trials are necessary to confirm its efficacy.

Shelf-life of a 2.5% sodium hypochlorite solution as determined by arrhenius equation

Accelerated stability tests are indicated to assess, within a short time, the degree of chemical degradation that may affect an active substance, either alone or in a formula, under normal storage conditions. This method is based on increased stress conditions to accelerate the rate of chemical degradation. Based on the equation of the straight line obtained as a function of the reaction order (at 50 and 70 ºC) and using Arrhenius equation, the speed of the reaction was calculated for the temperature of 20 ºC (normal storage conditions). This model of accelerated stability test makes it possible to predict the chemical stability of any active substance at any given moment, as long as the method to quantify the chemical substance is available. As an example of the applicability of Arrhenius equation in accelerated stability tests, a 2.5% sodium hypochlorite solution was analyzed due to its chemical instability. Iodometric titration was used to quantify free residual chlorine in the solutions. Based on data obtained keeping this solution at 50 and 70 ºC, using Arrhenius equation and considering 2.0% of free residual chlorine as the minimum acceptable threshold, the shelf-life was equal to 166 days at 20 ºC. This model, however, makes it possible to calculate shelf-life at any other given temperature.

Expressão da proteína erbB-2 e dos receptores de hormônios na transição das regiões in situ para invasora de tumores da mama

OBJETIVOS: avaliar a expressão de erbB-2 e dos receptores hormonais para estrógeno e progesterona (RE/RP) nas regiões de transição entre as frações in situ e invasoras de neoplasias ductais da mama (CDIS e CDI, respectivamente). MÉTODOS: oitenta e cinco casos de neoplasias mamárias, contendo regiões contíguas de CDIS e CDI, foram selecionados. Espécimes histológicos das áreas de CDIS e de CDI foram obtidos através da técnica de tissue microarray (TMA). As expressões da erbB-2 e dos RE/RP foram avaliadas por meio de imunoistoquímica convencional. A comparação da expressão da erbB-2 e dos RE/RP nas frações in situ e invasoras da mama foi realizada com emprego do teste de McNemar. Os intervalos de confiança foram determinados em 5% (p=0,05). Foram calculados coeficientes de correlação intraclasse (ICC) para avaliar a concordância na tabulação cruzada da expressão de erbB-2 e RE/RP nas frações de CDIS e CDI. RESULTADOS: a expressão da erbB-2 não diferiu entre as áreas de CDIS e CDI (p=0,38). Comparando caso a caso suas áreas de CDIS e CDI, houve boa concordância na expressão da erbB-2 (coeficiente de correlação intraclasse, ICC=0,64), dos RP (ICC = 0,71) e dos RE (ICC = 0,64). Considerando apenas tumores cujo componente in situ apresentasse áreas de necrose (comedo), o ICC para erbB-2 foi de 0,4, comparado a 0,6 no conjunto completo de casos. Os ICC não diferiram substancialmente daqueles obtidos com o conjunto completo de espécimes em relação aos RE/RP: para RE, ICC=0,7 (versus 0,7 no conjunto completo), e para RP, ICC=0,7 (versus 0,6 no conjunto completo). CONCLUSÕES: nossos achados sugerem que as expressões de erbB-2 e RE/RP não diferem nos componentes contíguos in situ e invasivo em tumores ductais da mama.

Bottle feeding, increased overjet and Class 2 primary canine relationship: is there any association?

The aim of this study was to investigate the association between bottle feeding and prevalence rates of increased overjet and Class 2 primary canine relationship. The sample consisted of 911 children (461 boys, 450 girls) aged 3 (13.9%), 4 (40.8%), 5 (34%) and 6 (11.3%) years, with complete primary dentition. Information about nutritive and nonnutritive (pacifier and/or digit) sucking habits was collected through questionnaires. Three calibrated dentists (κ: 0.9-1.0 and Rs > 0.90) performed the clinical assessments. The children were divided into four groups: G1 - not bottle-fed; G2 - exclusively bottle-fed; G3 - breast- and bottle-fed, bottle feeding ceased before 3 years of age; and G4 - breast- and bottle-fed, bottle feeding ceased between 3 and 4 years of age. Associations between nutritive and nonnutritive sucking behaviors and the malocclusions studied were analyzed by multiple binary logistic regression (α= 0.05). The frequencies of increased overjet were: 25.3% (G1), 38.8% (G2), 39.2% (G3) and 47.8% (G4). The percentages of Class 2 canine relationship were: 27.9% (G1), 48.8% (G2), 43.4% (G3) and 43% (G4). No significant effect of bottle feeding was found. The chances of diagnosing increased overjet (O.R. = 4.42, p < 0.001) and Class 2 canine relationship (O.R. = 4.02, p < 0.001) were greater for children with pacifier and/or digit-sucking habits, compared to those without a history of nonnutritive sucking behavior. It may be suggested that bottle feeding alone is not directly associated with higher prevalence rates of increased overjet and Class 2 canine relationship in the primary dentition.

Association of polymorphisms at the ADIPOR1 regulatory region with type 2 diabetes and body mass index in a Brazilian population with European or African ancestry

Association studies between ADIPOR1 genetic variants and predisposition to type 2 diabetes (DM2) have provided contradictory results. We determined if two single nucleotide polymorphisms (SNP c.-8503G>A and SNP c.10225C>G) in regulatory regions of ADIPOR1 in 567 Brazilian individuals of European (EA; N = 443) or African (AfA; N = 124) ancestry from rural (quilombo remnants; N = 439) and urban (N = 567) areas. We detected a significant effect of ethnicity on the distribution of the allelic frequencies of both SNPs in these populations (EA: -8503A = 0.27; AfA: -8503A = 0.16; P = 0.001 and EA: 10225G = 0.35; AfA: 10225G = 0.51; P < 0.001). Neither of the polymorphisms were associated with DM2 in the case-control study in EA (SNP c.-8503G>A: DM2 group -8503A = 0.26; control group -8503A = 0.30; P = 0.14/SNP 10225C>G: DM2 group 10225G = 0.37; control group 10225G = 0.32; P = 0.40) and AfA populations (SNP c.-8503G>A: DM2 group -8503A = 0.16; control group -8503A = 0.15; P = 0.34/SNP 10225C>G: DM2 group 10225G = 0.51; control group 10225G = 0.52; P = 0.50). Similarly, none of the polymorphisms were associated with metabolic/anthropometric risk factors for DM2 in any of the three populations, except for HDL cholesterol, which was significantly higher in AfA heterozygotes (GC = 53.75 ± 17.26 mg/dL) than in homozygotes. We conclude that ADIPOR1 polymorphisms are unlikely to be major risk factors for DM2 or for metabolic/anthropometric measurements that represent risk factors for DM2 in populations of European and African ancestries.