Sulfadiazine-selective determination in aquaculture environment: Selective potentiometric transduction by neutral or charged ionophores

Solid-contact sensors for the selective screening of sulfadiazine (SDZ) in aquaculture waters are reported. Sensor surfaces were made from PVC membranes doped with tetraphenylporphyrin-manganese(III) chloride, α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin ionophores that were dispersed in plasticizer. Some membranes also presented a positive or a negatively charged additive. Phorphyrin-based sensors relied on a charged carrier mechanism. They exhibited a near-Nernstian response with slopes of 52 mV decade−1 and detection limits of 3.91 × 10−5 mol L−1. The addition of cationic lipophilic compounds to the membrane originated Nernstian behaviours, with slopes ranging 59.7–62.0 mV decade−1 and wider linear ranges. Cyclodextrin-based sensors acted as neutral carriers. In general, sensors with positively charged additives showed an improved potentiometric performance when compared to those without additive. Some SDZ selective membranes displayed higher slopes and extended linear concentration ranges with an increasing amount of additive (always <100% ionophore). The sensors were independent from the pH of test solutions within 2–7. The sensors displayed fast response, always <15 s. In general, a good discriminating ability was found in real sample environment. The sensors were successfully applied to the fast screening of SDZ in real waters samples from aquaculture fish farms. The method offered the advantages of simplicity, accuracy, and automation feasibility. The sensing membrane may contribute to the development of small devices allowing in locus measurements of sulfadiazine or parent-drugs.

Trimethoprim-selective electrodes with molecularly imprinted polymers acting as ionophores and potentiometric transduction on graphite solid-contact

This work proposes a new biomimetic sensor material for trimethoprim. It is prepared by means of radical polymerization, having trimethylolpropane trimethacrylate as cross-linker, benzoyl peroxide as radicalar iniciator, chloroform as porogenic solvent, and methacrylic acid and 2-vinyl pyridine as monomers. Different percentages of sensor in a range between 1 and 6% were studied. Their behavior was compared to that obtained with ion-exchanger quaternary ammonium salt (additive tetrakis(p-chlorophenyl)borate or tetraphenylborate). The effect of an anionic additive in the sensing membrane was also tested. Trimethoprim sensors with 1% of imprinted particles from methacrylic acid monomers showed the best response in terms of slope (59.7 mV/decade) and detection limit (4.01 × 10− 7 mol/L). These electrodes displayed also a good selectivity towards nickel, manganese aluminium, ammonium, lead, potassium, sodium, iron, chromium, sulfadiazine, alanine, cysteine, tryptophan, valine and glycine. The sensors were not affected by pH changes from 2 to 6. They were successfully applied to the analysis of water from aquaculture.

New sensing materials of molecularly-imprinted polymers for the selective recognition of Chlortetracycline

As a result of the stressful conditions in aquaculture facilities there is a high risk of bacterial infections among cultured fish. Chlortetracycline (CTC) is one of the antimicrobials used to solve this problem. It is a broad spectrum antibacterial active against a wide range of Gram-positive and Gram-negative bacteria. Numerous analytical methods for screening, identifying, and quantifying CTC in animal products have been developed over the years. An alternative and advantageous method should rely on expeditious and efficient procedures providing highly specific and sensitive measurements in food samples. Ion-selective electrodes (ISEs) could meet these criteria. The only ISE reported in literature for this purpose used traditional electro-active materials. A selectivity enhancement could however be achieved after improving the analyte recognition by molecularly imprinted polymers (MIPs). Several MIP particles were synthesized and used as electro-active materials. ISEs based in methacrylic acid monomers showed the best analytical performance according to slope (62.5 and 68.6 mV/decade) and detection limit (4.1 × 10−5 and 5.5 × 10−5 mol L−1). The electrodes displayed good selectivity. The ISEs are not affected by pH changes ranging from 2.5 to 13. The sensors were successfully applied to the analysis of serum, urine and fish samples.

Selective recognition in potentiometric transduction of amoxicillin by molecularly imprinted materials

The indiscriminate use of antibiotics in food-producing animals has received increasing attention as a contributory factor in the international emergence of antibiotic-resistant bacteria (Woodward in Pesticide, veterinary and other residues in food, CRC Press, Boca Raton, 2004). Numerous analytical methods for quantifying antibacterial residues in edible animal products have been developed over years (Woodward in Pesticide, veterinary and other residues in food, CRC Press, Boca Raton, 2004; Botsoglou and Fletouris in Handbook of food analysis, residues and other food component analysis, Marcel Dekker, Ghent, 2004). Being Amoxicillin (AMOX) one of those critical veterinary drugs, efforts have been made to develop simple and expeditious methods for its control in food samples. In literature, only one AMOX-selective electrode has been reported so far. In that work, phosphotungstate:amoxycillinium ion exchanger was used as electroactive material (Shoukry et al. in Electroanalysis 6:914–917, 1994). Designing new materials based on molecularly imprinted polymers (MIPs) which are complementary to the size and charge of AMOX could lead to very selective interactions, thus enhancing the selectivity of the sensing unit. AMOX-selective electrodes used imprinted polymers as electroactive materials having AMOX as target molecule to design a biomimetic imprinted cavity. Poly(vinyl chloride), sensors of methacrylic acid displayed Nernstian slopes (60.7 mV/decade) and low detection limits (2.9 × 10−5 mol/L). The potentiometric responses were not affected by pH within 4–5 and showed good selectivity. The electrodes were applied successfully to the analysis of real samples.

Treatment of Vascular Lesions of the Tongue with Nd: YAG Laser

The treatment of vascular lesions of the tongue is a very challenging procedure since the maintenance of the lingual tissue is of critical importance. Numerous treatment options have been described in literature but the Nd:YAG Laser appears to be one of the safest therapeutic options. We described a successful treatment of vascular lesions of the tongue with an excellent clinical result after only one treatment session with the Nd:YAG laser, with conservation of the lingual tissue and its functionality.

Nitrite biosensing via selective enzymes—a long but promising route

Sensors 2010, 10, 11530-11555

Prostatic Arterial Supply: Anatomic and Imaging Findings Relevant for Selective Arterial Embolization

PURPOSE: To describe the anatomy and imaging findings of the prostatic arteries (PAs) on multirow-detector pelvic computed tomographic (CT) angiography and digital subtraction angiography (DSA) before embolization for symptomatic benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: In a retrospective study from May 2010 to June 2011, 75 men (150 pelvic sides) underwent pelvic CT angiography and selective pelvic DSA before PA embolization for BPH. Each pelvic side was evaluated regarding the number of independent PAs and their origin, trajectory, termination, and anastomoses with adjacent arteries. RESULTS: A total of 57% of pelvic sides (n = 86) had only one PA, and 43% (n = 64) had two independent PAs identified (mean PA diameter, 1.6 mm ± 0.3). PAs originated from the internal pudendal artery in 34.1% of pelvic sides (n = 73), from a common trunk with the superior vesical artery in 20.1% (n = 43), from the anterior common gluteal-pudendal trunk in 17.8% (n = 38), from the obturator artery in 12.6% (n = 27), and from a common trunk with rectal branches in 8.4% (n = 18). In 57% of pelvic sides (n = 86), anastomoses to adjacent arteries were documented. There were 30 pelvic sides (20%) with accessory pudendal arteries in close relationship with the PAs. No correlations were found between PA diameter and patient age, prostate volume, or prostate-specific antigen values on multivariate analysis with logistic regression. CONCLUSIONS: PAs have highly variable origins between the left and right sides and between patients, and most frequently arise from the internal pudendal artery.

Bartholin's Gland Cysts: Management with Carbon-Dioxide Laser Vaporization

OBJETIVO: Avaliar a eficácia, a taxa de recorrência e as complicações da vaporização laser com CO2 no tratamento dos cistos da glândula de Bartholin. MÉTODOS: Estudo retrospectivo com 127 pacientes que apresentavam cistos sintomáticos da glândula de Bartholin submetidas à vaporização laser CO2 na nossa instituição de janeiro de 2005 a junho de 2011. Foram excluídas todas as pacientes com abcessos da glândula de Bartholin ou com suspeita de câncer. Todos os procedimentos foram realizados em regime ambulatorial, sob anestesia local. A coleta dos dados foi feita com base na consulta do processo clínico, tendo-se procedido à análise das características demográficas, dos parâmetros anatômicos, das complicações intra e pós-operatórias e dos dados de acompanhamento. Os dados foram armazenados e analisados no software Microsoft Excel® 2007, e os resultados foram apresentados como frequência (porcentagem) ou média±desvio padrão. As taxas de complicações, recorrência e cura foram calculadas. RESULTADOS: A idade média das pacientes foi de 37,3±9,5 anos (variando entre 18 e 61 anos). Setenta por cento(n=85) delas eram multíparas. A queixa mais frequente foi dor e 47,2% (n=60) das pacientes tinham antecedentes de tratamento médico e/ou cirúrgico por abcesso da glândula de Bartholin. A dimensão média dos cistos foi de 2,7±0,9 cm. Foram verificados três (2,4%) casos de hemorragia intraoperatória ligeira e 17 (13,4%) recorrências durante um período médio de 14,6 meses (variando entre 1 e 56 meses): dez abscessos da glândula de Bartholin e sete cistos recorrentes, que precisavam de uma nova intervenção cirúrgica. A taxa de cura após um único tratamento à laser foi de 86,6%. Dentre as cinco pacientes com doença recorrente que foram submetidas a um segundo procedimento com laser, a taxa de cura foi de 100%. CONCLUSÕES: Na presente instituição, a vaporização laser com CO2 parece ser uma opção terapêutica segura e eficaz no tratamento dos cistos da glândula de Bartholin.

The role of microRNAs in amyotrophic lateral sclerosis

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina

Correlation between the mechanical cycling behavior and microstructure in laser welded joints using NiTi memory shape alloys

Dissertação para obtenção do Grau de Mestre em Engenharia de Materiais

Monoterapia com Laser na Fasceíte Plantar

Introdução: A fasceíte plantar (FP) constitui a causa mais frequente de dor no retropé. Está recomendada uma prova terapêutica inicial conservadora. Objetivos: Caraterizar fatores demográficos e sintomáticos, terapêutica prévia e resultados de monoterapia com laser. Material e Métodos: Estudo observacional retrospetivo (12 meses). O tratamento aplicado foi laser infravermelho (AsGa 904nm; densidade de energia 20J/cm2; potência de pico 200mW). Fez-se análise estatística descritiva e comparativa (nível de significância de 0,05). Resultados: Seguiram-se 32 doentes com FP, com idade média de 54,28 anos (24–86; DP 13,95), 66% mulheres, Índice de Massa Corporal (IMC) médio de 30,18Kg/m2 (17,91-41,13; DP 5,19), 75% unilaterais, tempo médio de evolução de 6,28 meses (0,2-24; DP 6,82), 21 tinham feito previamente farmacoterapia e 12 outros tratamentos de MFR. O nível de dor inicial (END) médio foi 7,31 (5-10; DP 1,38). Dos 26 doentes tratados (6 perdas), 24 (92,3%) reportaram melhoria. O número médio de sessões foi 28,5 (11– 60; DP 14,01). O nível médio de dor final foi 0,75 (0-5; DP 2,37), com melhoria média de 89,7% (28,6%-100%; DP 0,16) do nível de dor. A intensidade de dor inicial foi maior em doentes com IMC superior (p=0,002). Não se encontraram outras relações estatisticamente significativas. Conclusões: A FP caraterizou-se por um nível de dor significativo (moderado a grave). A obesidade pareceu ser um fator de risco. A taxa de melhoria com o tratamento com laser foi muito satisfatória. A terapia com laser de baixa intensidade IV constitui uma boa opção terapêutica, a justificar avaliação suplementar por ensaios prospetivos controlados e randomizados.

Benefits of Selective Vitamin D Receptor Activators in Kidney Transplanted Patients

Severe chronic kidney disease may lead to disturbances, such as hyperphosphatemia, increased secretion of fibroblast growth factor -23 (FGF -23) and vitamin D deficiency. These may increase plasmatic levels of parathyroid hormone, and decrease plasmatic levels of calcium. Altogether, these may contribute to the development of secondary hyperparathyroidism, and to abnormalities in mineral metabolism. Kidney transplantation is the best option to improve longevity and quality of life in end -stage chronic kidney disease patients. Vitamin D deficiency has been associated with cardiovascular disease, which is the leading cause of death in chronic kidney disease. Therefore, diagnosing this deficiency may be pivotal for minimizing mortality in chronic kidney disease, because pharmacological treatments for this deficiency may be prescribed. Calcitriol is indicated for the treatment of vitamin D deficiency, both in chronic kidney disease and in kidney transplanted patients. However, calcitriol may increase the plasmatic levels of calcium and phosphorous, which can lead to vascular calcifications, that have been associated with cardiovascular mortality. Selective vitamin D receptor activators are indicated for the treatment of vitamin D deficiency in chronic kidney disease. These have the advantage of being associated with lower increases of plasmatic levels of calcium and phosphorous. These drugs also seem to have additional effects that may minimise patient morbidity and mortality, especially due to potentially reducing cardiovascular events. Unfortunately, there are few studies about the use of these drugs in kidney transplanted patients. Here we present a review about the physiology of vitamin D, the consequences of its deficiency in chronic kidney disease and in kidney transplanted patients, and about the diagnosis and treatment of this deficiency. Finally, we discuss the new line of research about the efficacy and safety of selective vitamin D receptor activators in kidney transplanted patients.

How to sell successfully a perfume in the non-selective market?

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Forno solar com lentes de Fresnel e aplicações em laser solar

Dissertação para obtenção do Grau de Mestre em Engenharia Física