Effect of NaCl additive on solute-solvent interactions in aqueous polyethylene glycol-sodium sulfate two-phase systems

Abstract Partition behavior of eight small organic compounds and six proteins was examined in poly(ethylene glycol)-8000-sodium sulfate aqueous two-phase systems containing 0.215 M NaCl and 0.5 M osmolyte (sorbitol, sucrose, TMAO) and poly(ethylene glycol)-10000-sodium sulfate-0.215 M NaCl system, all in 0.01 M sodium phosphate buffer, pH 6.8. The differences between the solvent properties of the coexisting phases (solvent dipolarity/polarizability, hydrogen bond donor acidity, and hydrogen bond acceptor basicity) were characterized with solvatochromic dyes using the solvatochromic comparison method. Differences between the electrostatic properties of the phases were determined by analysis of partitioning of sodium salts of dinitrophenylated (DNP-) amino acids with aliphatic alkyl side-chain. The partition coefficients of all compounds examined (including proteins) were described in terms of solute-solvent interactions. The results obtained in the study show that solute-solvent interactions of nonionic organic compounds and proteins in polyethylene glycol-sodium sulfate aqueous two-phase system change in the presence of NaCl additive.

Epigastric pain: incarceration or rotation?

Introduction: Acute intrathoracic gastric volvulus occurs when the stomach has a twist mesenteroaxial/organoaxial or chest cavity resulting in a dilatation or rupture of the diaphragmatic hiatus or diaphragmatic hernia. The purpose of this work is to show a interesting case of gastric volvulus in a patient with several comorbidities. Case Report: A 77-year-old female with past history of hiatal hernia and mental disease associated with diabetes and atrial fibrillation. Patient went to the emergency department due to vomiting associated with blood. Analytical parameters (WBC, HGB, PCR, metabolic panel and liver function), showed no significant alterations. Thoracic X-ray revealed an enlarged mediastinum due to herniation of the stomach. A computed tomography (CT) scan confirmed intrathoracic localization of the gastric antrum with twist. Patient’s symptoms were relieved by nasogastric intubation and analgesia. After six months, the patient is still asymptomatic. Conclusion: In general, the treatment of an acute gastric volvulus requires an emergent surgical repair. In patients who are not surgical candidates (with comorbidities or an inability to tolerate anesthesia), endoscopic reduction should be attempted. Chronic gastric volvulus may be treated non-emergently, and surgical treatment is increasingly being performed using a laparoscopic approach. In this case, it is a chronic form that was solved with the placement of the nasogastric tube. A nasogastric decompression is an option in the chronic form of hiatal hernia associated to gastric volvulus in patients with serious comorbidities.

Comparing different methods to measure biofilm thickness: the techniques are: optical coherence tomography, confocal laser scanning microscopy and low load compression test

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Engenharia Clínica)

Study of grapevine solute transporters involved in berry quality. A biochemical and molecular approach

Tese de Doutoramento em Biologia de Plantas

Pneumomediastino espontâneo como apresentação de infecção por Mycoplasma pneumoniae

Introdução: O pneumomediastino espontâneo (PE) define-se pela presença de ar livre no mediastino, sem causa traumática. É raro em idade pediátrica e exige elevada suspeição diagnóstica. Caso Clínico: Adolescente de 17 anos, longilíneo, fumador ocasional, sem história traumática nem patologia pulmonar, observado na Urgência por dor retrosternal intensa acompanhada por dispneia ligeira. Referência a acessos de tosse seca violenta horas antes. O diagnóstico de PE suspeitou-se pela palpação de enfisema subcutâneo supraclavicular e confirmou-se por telerradiografia do tórax mostrando ar livre mediastínico. A investigação revelou infeção por Mycoplasma pneumoniae pelo que foi medicado com macrólido para além do repouso e analgesia propostos para o PE, evoluindo favoravelmente. Discussão/Conclusôes: O PE é um diagnóstico a não esquecer perante dor torácica aguda no adolescente. A presença de sintomas, por vezes, frustres e a evolução habitualmente benigna contribuem para um provável subdiagnóstico. O tabagismo é um fator predisponente. A associação a infeção por Mycoplasma pneumoniae só raramente foi descrita.

Effect of sodium chloride on solutesolvent interactions in aqueous polyethylene glycolsodium sulfate two-phase systems

Partition behavior of eight small organic compounds and six proteins was examined in poly(ethylene glycol)-8000sodium sulfate aqueous two-phase systems containing 0.215 M NaCl and 0.5 M osmolyte (sorbitol, sucrose, TMAO) and poly(ethylene glycol)-10000sodium sulfate0.215 M NaCl system, all in 0.01 M sodium phosphate buffer, pH 6.8. The differences between the solvent properties of the coexisting phases (solvent dipolarity/polarizability, hydrogen bond donor acidity, and hydrogen bond acceptor basicity) were characterized with solvatochromic dyes using the solvatochromic comparison method. Differences between the electrostatic properties of the phases were determined by analysis of partitioning of sodium salts of dinitrophenylated (DNP-) amino acids with aliphatic alkyl side-chain. The partition coefficients of all compounds examined (including proteins) were described in terms of solutesolvent interactions. The results obtained in the study show that solutesolvent interactions of nonionic organic compounds and proteins in polyethylene glycolsodium sulfate aqueous two-phase system change in the presence of NaCl additive.

Biotechnological production and application of fructooligosaccharides

Currently, prebiotics are all carbohydrates of relatively short chain length. An important group is the fructooligosaccharides, which are a special kind of prebiotics associated to their selective stimulation of the activity of certain groups of colonic bacteria that have a positive and beneficial effect on intestinal microbiota, reducing incidence of gastrointestinal infections, respiratory and also possessing a recognized bifidogenic effect. Traditionally, these prebiotic compounds have been obtained through extraction processes from some plants, as well as through enzymatic hydrolysis of sucrose. However, different fermentative methods have also been proposed for the production of fructooligosaccharides, such as solid-state fermentation utilizing various agroindustrial by-products. By optimizing the culture parameters, fructooligosaccharides yields and productivity can be improved. The use of immobilized enzymes and cells has also been proposed as being an effective and economic method for large-scale production of fructooligosaccharides. This paper is an overview on the results of recent studies on fructooligosacharides biosynthesis, physicochemical properties, sources, biotechnological production and applications.