Covalent Immobilization of Aldehyde and Alcohol Dehydrogenases on Ordered Mesoporous Silicas

Purpose This work studies the immobilization of two enzymes, the alcohol dehydrogenase (ADH) and the aldehyde dehydrogenase (AldDH) both from Saccharomyces cerevisiae, which could be used to produce high value-added molecules from carboxylic acids embedded in anaerobic digestate.Methods In particular, three mesoporous siliceous materials, with different specific surface areas and pore sizes, (MSU-H, MSU-F and MCF0.75) were used as supports for covalent immobilization. The support materials were characterized by complementary techniques. Then, after a functionalization, creating a covalent bond between the enzyme and the support was performed. The specific activity and immobilization yield of the biocatalysts were then evaluated.Results The best results were obtained with MSU-H and MSU-F, resulting in an immobilization yield greater than 50% in all cases, a specific activity of 0.13 IU/g(supp) with the AldDH/MSU-H, 0.10 IU/g(supp) with AldDH/MSU-F, 48.6 IU/g(supp) with ADH/MSU-H and 12.6 IU/g(supp) with ADH/MSU-H. These biocatalysts were then characterized by optimal pH and temperature and the stability factor was evaluated. With ADH/MSU-F no decrease in activity was observed after 120 h incubated at 50 degrees C. Finally, the biocatalysts AldDH/MSU-H and ADH/MSU-H were used to perform the reduction reaction and it was seen that after five reaction cycles the residual activity was greater than 20% in both cases.Conclusion The ADH and AldDH enzymes have been successfully immobilized on mesoporous siliceous supports, considerably increasing their thermal stability and being able to reuse them for several reaction cycles. The use of this immobilization and these supports is adaptable to a wide variety of enzymes

Innovative strategies for evaluating stressful conditions in urban environments

Ornamental and spontaneous plants in urban areas can provide several benefits to citizens from an aesthetical and environmental quality point of view. The beneficial effects of plants can be obtained if suitable ornamental species are selected for the different stressful conditions of different urban areas. The use of plants with adequate tolerance can effectively provide through their physiology processes oxygen, temperature mitigation, uptake of pollutants, and valorization of urban spaces. The aim of this work was to use non-destructive measurements such as chlorophyll a fluorescence, chlorophyll, water soil content, temperature, and solar radiation of a defined urban area for the identification of the different degrees of stress conditions. The measurements will be carried out on herbaceous, shrubs and ornamental trees such as Trifolium pratense L., Malva sylvestris L., Sorghum halepense (L.) Pers., Artemisia verlotiorum Lamotte, Ulmus minor Miller, Ailanthus altissima (Miller) Swingle, Buddleja davidii Franchet, located in the study area. Data will be analyzed using the JIP test for the identification of potential chlorophyll a fluorescence indexes, which will be correlated with the environmental parameters. These data will be used for the visualization of the stressful sites, the different tolerance of the botanical species distributed in the areas, and the selection of the best potential species for the different stress conditions. The highest potential benefits from plants can be only achieved if the correct species with the adequate tolerances will be used in the different urban environments

Covalent Immobilization of Dehydrogenases on Carbon Felt for Reusable Anodes with Effective Electrochemical Cofactor Regeneration

This study presents the immobilization with aldehyde groups (glyoxyl carbon felt) of alcohol dehydrogenase (ADH) and formate dehydrogenase (FDH) on carbon-felt-based electrodes. The compatibility of the immobilization method with the electrochemical application was studied with the ADH bioelectrode. The electrochemical regeneration process of nicotinamide adenine dinucleotide in its oxidized form (NAD(+)), on a carbon felt surface, has been deeply studied with tests performed at different electrical potentials. By applying a potential of 0.4 V versus Ag/AgCl electrode, a good compromise between NAD(+) regeneration and energy consumption was observed. The effectiveness of the regeneration of NAD(+) was confirmed by electrochemical oxidation of ethanol catalyzed by ADH in the presence of NADH, which is the no active form of the cofactor for this reaction. Good reusability was observed by using ADH immobilized on glyoxyl functionalized carbon felt with a residual activity higher than 60 % after 3 batches

Prevalence of adenoma of gallbladder, ultrasonographic and histological assessment in a retrospective series of 450 cholecystectomy

OBJECTIVES: Adenomyomas of the gallbladder (GA) are difficult to examine during standard ultrasound examination of the abdomen. They sometimes undergo malignant transformation and their optimal management still remains a problem. The authors have aimed to investigate the ultrasonographic (US) and histopathological prevalence of GA focusing on the diagnostic performance of US examination. MATERIALS AND METHODS: A retrospective series of 450 consecutive patients who underwent cholecystectomy is reported. Data regarding characteristics of the patients, US and histology examination of the gallbladder were collected. Sensitivity, specificity, positive and negative predictive values of US were calculated with respect to histological examination of the gallbladder. RESULTS: The study group consisted of 261 female and 189 male. US scan detected adenomyomas in 22 patients, confirmed by histopathology in 13 and found to be not present in 9. Incidental adenomyomas were found in 16 patients of 428 who underwent cholecystectomy for gallstones. Prevalence was 4.9% and 6.4% for US scan and histopathology respectively. US scan showed sensitivity of 43.3% (c.i.:25.4%-62.5%), specificity of 97.8% (c.i.:95.9%-99%) with a positive predictive value of 59% (c.i.:36.3%-79.2%) and with a negative predictive value of 96.2% (c.i.:93.7%- 97.6%). On histopathology, adenomyomas localized in the fundus were predominant. Two female patients with adenomyomas of the fundus (diameter 5 mm) and single stone showed intestinal metaplasia with high-grade dysplasia. CONCLUSIONS: The diagnosis of gallbladder adenomyomas by US scan still remains a problem because of its low sensitivity, which is mainly due to the association with gallstones. At present, the selection of patients requiring cholecystectomy is still controversial, surgery is indicated in the presence of GA>1cm and if symptomatic cholelithiasis is present, with respect to polyps smaller than 1cm the presence of diameter increase, the association of thickening (>3mm) of the gallbladder wall and the presence of dysmorphism at follow-up with US are widely considedered as indications for surgey. In our study histopathological findings in the perilesional mucosa confirm the hypothesis of a metaplasia-dysplasia-carcinoma sequence already shown in the colon-rectum, even if no cancer were found. According with our results surgery is proposed when GA is associated with cholelithiasis in all cases because of the increased risk of malignancy development, independently from the dimension of lesion

Rara causa di addome acuto: l’infarto splenico. Caso clinico e revisione della letteratura

Caso clinico. Donna di 97 anni con dolore nel quadrante addominale superiore sinistro e febbre da circa 20 giorni. Storia clinica di fibrillazione atriale cronica. Gli esami ematochimici dimostravano leucocitosi, trombocitosi, aumento di PCR e LDH. L’ecotomografia evidenziava in sede splenica un’estesa area ipoecogena. La diagnosi di infarto splenico veniva confermata dalla TC con mezzo di contrasto (mdc). La paziente veniva sottoposta ad antibioticoterapia a largo spettro, con efficace controllo dei segni locali e sistemici di infiammazione. Dimissione in XVI giornata. Discussione. La diagnosi di infarto splenico è basata sulla combinazione tra manifestazioni cliniche e imaging. La TC con mdc rappresenta il gold standard. L’ecotomografia e la radiologia convenzionale forniscono utili informazioni per la diagnosi differenziale con affezioni toraciche o addominali causa di dolore e febbre. Nel caso da noi osservato l’età avanzata della paziente, le precarie condizioni cardiorespiratorie, la stabilità emodinamica e il rapido controllo farmacologico della sepsi hanno consigliato il trattamento conservativo. Conclusioni. Nel nostro caso l’infarto splenico è stato conseguenza di evento embolico da fibrillazione atriale cronica. Alla luce dei dati riportati in letteratura e della nostra esperienza, il trattamento di scelta è la terapia medica. La splenectomia precoce, open o laparoscopica, va riservata al trattamento delle complicanze

A RARE CAUSE OF ACUTE ABDOMEN: SPLENIC INFARCTION. CASE REPORT AND REVIEW OF THE LITERATURE.

INTRODUCTION: Splenic infarction is a rare cause of acute abdomen. It must be suspected in patient with hematologic diseases or thromboembolic conditions. The most common onset symptom is left-upper quadrant abdominal pain. Additional symptoms include fever and anemia. Laboratory may show elevated white blood cell and platelet counts. CASE REPORT: A 97-year-old female with a past history of atrial fibrillation presented with left-upper quadrant abdominal pain and fever since 20 days. Laboratory showed elevated white blood cell and platelet counts, increased C-reactive protein and lactate dehydrogenase. Both ultrasonographic and tomographic scans showed a large hypodense area of the spleen. The patient received intravenous antibiotic therapy, which led to significant clinical improvement with discharge 16 days after admission. DISCUSSION: The diagnosis of splenic infarction is based both on clinical presentation and imaging studies. Angio-computed tomography is the diagnostic procedure of choice. Ultrasonography and conventional radiology are useful in the differential diagnosis with other abdominal and thoracic diseases mimicking splenic infarction. In our case the management was conservative, because the patient was hemodynamically stable and antibiotic therapy could control the sepsis. Moreover, advanced age and poor cardiac and respiratory conditions contraindicated surgery. CONCLUSIONS: In our case splenic infarction was probably due to a thromboembolic event secondary to atrial fibrillation. In accordance with the literature, we suggest initial conservative therapy. Surgery is indicated only in the presence of complications

Endoscopic sphincterotomy of the major duodenal papilla in acute relapsing pancreatitis associated with pancreas divisum: a case report

Gli Autori riportano un caso di pancreatite acuta ricorrente associata a pancreas divisum. La paziente è stata sottoposta a sfinterotomia endoscopica della papilla duodenale maggiore, dopo fallimento dell’incannulazione della papilla minore. La paziente è asintomatica ai controlli clinici e di laboratorio a lungo termine. Vengono discussi i possibili meccanismi alla base del successo terapeutico

Endoscopic sphincterotomy of the major duodenal papilla in acute relapsing pancreatitis associated with pancreas divisum: a case report.

We report a case of acute relapsing pancreatitis associated with pancreas divisum, who underwent major papilla sphincterotomy after failed minor papilla cannulation. Long-term results were satisfactory. The possible explanations of the efficacy of major papilla endoscopic resection in this particular case are discussed