Improved Process for the Continuous Acylation of 1,3-Benzodioxole

The acylation of 1,3-benzodioxole was studied in a continuous process using a recyclable heterogeneous substoichiometric catalyst. In a short time period (30 min), at 100 °C, the conversion rate was 73%, with a selectivity of 62% of the desired acylated product; the reaction was run continuously for 6 h, showing excellent stability and selectivity. Moreover, the unreacted starting material, 1,3-benzodioxole, can be easily separated by distillation and recycled.

Lipase-mediated flow synthesis of nature-inspired phenolic carbonates

A facile and convenient lipase-catalyzed flow approach for the chemoselective synthesis of tyrosol and hydroxytyrosol methyl carbonates has been developed in neat dimethylcarbonate. The products were obtained in quantitative yield with high catalyst productivity. The biocatalytic approach was then exploited for the preparation of value-added symmetrical tyrosol and hydroxytyrosol carbonates.

From Batch to Continuous Flow Bioprocessing: Use of an Immobilized γ-Glutamyl Transferase from B. subtilis for the Synthesis of Biologically Active Peptide Derivatives

γ-Glutamyl-peptides are frequently endowed with biological activities. In this work, "kokumi peptides" such as γ-glutamyl-methionine (1) and γ-glutamyl-(S)-allyl-cysteine (2), as well as the neuroprotective γ-glutamyl-taurine (3) and the antioxidant ophthalmic acid (4), were synthesized through an enzymatic transpeptidation reaction catalyzed by the γ-glutamyl transferase from Bacillus subtilis (BsGGT) using glutamine as the γ-glutamyl donor. BsGGT was covalently immobilized on glyoxyl-agarose resulting in high protein immobilization yield and activity recovery (>95%). Compounds 1-4 were obtained in moderate yields (19-40%, 5-10 g/L) with a variable purity depending on the presence of the main byproduct (γ-glutamyl-glutamine, 0-16%). To achieve process intensification and better control of side reactions, the synthesis of 2 was moved from batch to continuous flow. The specific productivity was 1.5 times higher than that in batch synthesis (13.7 μmol/min*g), but it was not accompanied by a paralleled improvement of the impurity profile.

Enzymatic continuous-flow preparation of nature-inspired phenolic esters as antiradical and antimicrobial agents

A collection of nature-inspired lipophilic phenolic esters have been prepared by an enzymatic synthesis under flow conditions, using the immobilized lipase B from Candida antarctica (Novozyme 435®) as a catalyst in cyclopentyl methyl ether (CPME), a non-conventional and green solvent. Their antimicrobial activity against four selected bacterial strains together with their efficiency as radical scavengers were evaluated. The obtained compounds were characterized by enhanced lipophilicity in comparison with the parent non-esterified compounds, which increased the possibility of their use as additives in the food industry.

Biocatalytic Approaches for an Efficient and Sustainable Preparation of Polyphenols and Their Derivatives

Many sectors of industry, such as food, cosmetics, nutraceuticals, and pharmaceuticals, have increased their interest in polyphenols due to their beneficial properties. These molecules are widely found in Nature (plants) and can be obtained through direct extraction from vegetable matrices. Polyphenols introduced through the diet may be metabolized in the human body via different biotransformations leading to compounds having different bioactivities. In this context, enzyme-catalyzed reactions are the most suitable approach to produce modified polyphenols that not only can be studied for their bioactivity but also can be labeled as green, natural products. This review aims to give an overview of the potential of biocatalysis as a powerful tool for the modification of polyphenols to enhance their bioaccessibility, bioavailability, biological activity or modification of their physicochemical properties. The main polyphenol transformations occurring during their metabolism in the human body have been also presented.

Chemoenzymatic synthesis of arabinomannan (AM) glycoconjugates as potential vaccines for tuberculosis

Mycobacteria infection resulting in tuberculosis (TB) is one of the top ten leading causes of death worldwide in 2018, and lipoarabinomannan (LAM) has been confirmed to be the most important antigenic polysaccharide on the TB cell surface. In this study, a convenient synthetic method has been developed for synthesizing three branched oligosaccharides derived from LAM, in which a core building block was prepared by enzymatic hydrolysis in flow chemistry with excellent yield. After several steps of glycosylations, the obtained oligosaccharides were conjugated with recombinant human serum albumin (rHSA) and the ex-vivo ELISA tests were performed using serum obtained from several TB-infected patients, in order to evaluate the affinity of the glycoconjugate products for the human LAM-antibodies. The evaluation results are positive, especially compound 21 that exhibited excellent activity which could be considered as a lead compound for the future development of a new glycoconjugated vaccine against TB.

Immobilized enzyme reactors based on nucleoside phosphorylases and 2'-deoxyribosyltransferase for the in-flow synthesis of pharmaceutically relevant nucleoside analogues

In this work, a mono- and a bi-enzymatic analytical immobilized enzyme reactors (IMERs) were developed as prototypes for biosynthetic purposes and their performances in the in-flow synthesis of nucleoside analogues of pharmaceutical interest were evaluated. Two biocatalytic routes based on nucleoside 2'-deoxyribosyltransferase from Lactobacillus reuteri (LrNDT) and uridine phosphorylase from Clostridium perfrigens (CpUP)/purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) were investigated in the synthesis of 2'-deoxy, 2',3'-dideoxy and arabinonucleoside derivatives. LrNDT-IMER catalyzed the synthesis of 5-fluoro-2'-deoxyuridine and 5-iodo-2'-deoxyuridine in 65-59% conversion yield, while CpUP/AhPNP-IMER provided the best results for the preparation of arabinosyladenine (60% conversion yield). Both IMERs proved to be promising alternatives to chemical routes for the synthesis of nucleoside analogues. The developed in-flow system represents a powerful tool for the fast production on analytical scale of nucleosides for preliminary biological tests.

An Overview of Coumarin as a Versatile and Readily Accessible Scaffold with Broad-Ranging Biological Activities

Privileged structures have been widely used as an effective template for the research and discovery of high value chemicals. Coumarin is a simple scaffold widespread in Nature and it can be found in a considerable number of plants as well as in some fungi and bacteria. In the last years, these natural compounds have been gaining an increasing attention from the scientific community for their wide range of biological activities, mainly due to their ability to interact with diverse enzymes and receptors in living organisms. In addition, coumarin nucleus has proved to be easily synthetized and decorated, giving the possibility of designing new coumarin-based compounds and investigating their potential in the treatment of various diseases. The versatility of coumarin scaffold finds applications not only in medicinal chemistry but also in the agrochemical field as well as in the cosmetic and fragrances industry. This review is intended to be a critical overview on coumarins, comprehensive of natural sources, metabolites, biological evaluations and synthetic approaches.

Mutational spectrum and clinical signatures in 114 families with hereditary multiple osteochondromas: insights into molecular properties of selected exostosin variants

Hereditary multiple osteochondromas (HMO) is a rare autosomal dominant skeletal disorder, caused by heterozygous variants in either EXT1 or EXT2, which encode proteins involved in the biogenesis of heparan sulphate. Pathogenesis and genotype-phenotype correlations remain poorly understood. We studied 114 HMO families (158 affected individuals) with causative EXT1 or EXT2 variants identified by Sanger sequencing, or multiplex ligation-dependent probe amplification and qPCR. Eighty-seven disease-causative variants (55 novel and 32 known) were identified including frameshift (42%), nonsense (32%), missense (11%), splicing (10%) variants and genomic rearrangements (5%). Informative clinical features were available for 42 EXT1 and 27 EXT2 subjects. Osteochondromas were more frequent in EXT1 as compared to EXT2 patients. Anatomical distribution of lesions showed significant differences based on causative gene. Microscopy analysis for selected EXT1 and EXT2 variants verified that EXT1 and EXT2 mutants failed to co-localize each other and loss Golgi localization by surrounding the nucleus and/or assuming a diffuse intracellular distribution. In a cell viability study, cells expressing EXT1 and EXT2 mutants proliferated more slowly than cells expressing wild-type proteins. This confirms the physiological relevance of EXT1 and EXT2 Golgi co-localization and the key role of these proteins in the cell cycle. Taken together, our data expand genotype-phenotype correlations, offer further insights in the pathogenesis of HMO and open the path to future therapies.

An Enzymatic Flow-Based Preparative Route to Vidarabine

The bi-enzymatic synthesis of the antiviral drug vidarabine (arabinosyladenine, ara-A), catalyzed by uridine phosphorylase from Clostridium perfringens (CpUP) and a purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP), was re-designed under continuous-flow conditions. Glyoxyl–agarose and EziG^TM1 (Opal) were used as immobilization carriers for carrying out this preparative biotransformation. Upon setting-up reaction parameters (substrate concentration and molar ratio, temperature, pressure, residence time), 1 g of vidarabine was obtained in 55% isolated yield and >99% purity by simply running the flow reactor for 1 week and then collecting (by filtration) the nucleoside precipitated out of the exiting flow. Taking into account the substrate specificity of CpUP and AhPNP, the results obtained pave the way to the use of the CpUP/AhPNP-based bioreactor for the preparation of other purine nucleosides.

Prevalence, Type, and Molecular Spectrum of NF1 Mutations in Patients with Neurofibromatosis Type 1 and Congenital Heart Disease

The aim of this study was to assess the prevalence and type of congenital heart disease (CHD) and the associated mutation spectrum in a large series of patients with neurofibromatosis type 1 (NF1), and correlate the mutation type with the presence and subgroups of cardiac defects. The study cohort included 493 individuals with molecularly confirmed diagnosis of NF1 for whom cardiac evaluation data were available. CHD was reported in 62/493 (12.6%) patients. Among these patients, 23/62 (37.1%) had pulmonary valve stenosis/dysplasia, 20/62 (32.3%) had mitral valve anomalies, and 10/62 (16.1%) had septal defects. Other defects occurred as rare events. In this NF1 subcohort, three subjects carried a whole-gene deletion, while 59 were heterozygous for an intragenic mutation. A significantly increased prevalence of non-truncating intragenic mutations was either observed in individuals with CHD (22/59, 37.3%) or with pulmonary valve stenosis (13/20, 65.0%), when compared to individuals without CHD (89/420, 21.2%) (p = 0.038) or pulmonary valve stenosis (98/459, 21.4%) (p = 0.002). Similarly, patients with non-truncating NF1 mutations displayed two- and six-fold higher risk of developing CHD (odds ratio = 1.9713, 95% confidence interval (CI): 1.1162-3.4814, p = 0.0193) and pulmonary valve stenosis (odds ratio = 6.8411, 95% CI: 2.6574-17.6114, p = 0.0001), respectively. Noteworthy, all but one patient (19/20, 95.0%) with pulmonary valve stenosis, and 18/35 (51.4%) patients with other CHDs displayed Noonan syndrome (NS)-like features. Present data confirm the significant frequency of CHD in patients with NF1, and provide further evidence for a higher than expected prevalence of NF1 in-frame variants and NS-like characteristics in NF1 patients with CHD, particularly with pulmonary valve stenosis.

Effect of alcohol dehydrogenase-1B and -7 polymorphisms on blood ethanol and acetaldehyde concentrations in healthy subjects with a history of moderate alcohol consumption

This study aims to evaluate the effect of ADH1B and ADH7 genotypes on blood acetaldehyde and ethanol levels after alcohol ingestion, and to measure the genotoxic effect of smoking and ethanol on the buccal cells, also controlling for ADH variants. We recruited healthy Italian subjects with at least a moderate history of alcohol consumption. All subjects were given an alcoholic drink of 0.4 g ethanol /kg of body weight. Blood venous samples were collected at baseline, and 30, 60, 90, and 120 minutes after ingestion. Buccal cells were collected before ethanol ingestion. Sixty subjects were enrolled in the study. Individuals with the ADH1B GG genotype had median ethanol levels of 5.0mM (IQR 3.4-7.2), and those with the ADH1B GT/TT genotype had 4.7mM (IQR 4.2-4.8). Corresponding acetaldehyde levels were 1.5μM (IQR 0.7-2.6) for ADH1B GG genotype and 1.6μM (IQR 1.5-1.7) for ADH1B CG/GG genotype. Individuals with the ADH7 CC genotype had median ethanol levels of 5.0mM (IQR 3.3-7.2), while 5.0mM (IQR 4.7-5.6) was in those with the ADH7 CG/GG genotype. Corresponding acetaldehyde levels were 1.5 μM (IQR 0.7-2.6) for ADH7 CC genotype and 1.5 μM (IQR 1.4-1.6) for ADH7 CG/GG genotypes. A non-significant increase in the frequency of karyolitic and pyknotic cells was found in the group of heavy drinkers and current smokers, when compared to the moderate drinkers and the non-smokers. Our study does not support the hypothesis that ADH1B and ADH7 genotypes affect blood ethanol and acetaldehyde concentration.

Twenty years of gastroenteropancreatic neuroendocrine tumors: is reclassification worthwhile and feasible?

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are rare neoplasms with heterogeneous clinical behavior and potential long-term survival. In 2006/2007, the European Neuroendocrine Tumors Society introduced an important parameter, grade (based on mitoses and Ki-67 proliferation rate), which became part of the latest 2010-WHO classification. Since this is an important tool in the choice of therapeutic algorithm of patients with NETs, our aim was to audit whether retrospective reclassification is possible and feasible and correlate pathological findings with survival. From the histopathology archive, 338 GEP-NETs (1994-2014) were identified, of which 250 were diagnosed pre-2010 and 80 of these have needed, up till now, classification (morphology and grade-mitotic count/Ki-67). Morphology was well differentiated (WD) in 74 cases while only 6 cases were poorly differentiated (PD). Grade was reclassified: G1-45 cases (56 %); G2-28 cases (35 %); G3-7 cases (9 %). Overall survival (OS) in WD NETs was strikingly better compared to PD neoplasms. Differences in OS between grade were statistically significant (p < 0.0001) and, in particular, grade identified a subgroup of patients with WD lesions but with less favorable clinical behavior (OS at 5 years: G1-89 %; G2-48 %; G3-0 %; G1 vs G2 p = 0.03). Feasibility analysis quantified time for reclassification to be between 45 and 64 min/case. Our series confirms the importance of grade in prognostic stratification and underlines that reclassification is feasible, and may prove worthwhile in patient management, especially in view of the potential long survival of patients with NETs and risk of use of inappropriate therapies.

In vivo and in vitro response to octreotide LAR in a TSH-secreting adenoma: characterization of somatostatin receptor expression and role of subtype 5

Thyrotropin-secreting pituitary adenomas (TSHomas) are a rare cause of hyperthyroidism and account for less than 2% of pituitary adenomas. Medical therapy with somatostatin analogues (SSAs) effectively reduces TSH secretion in approximately 80% of patients and induces shrinkage in about 45% of tumors. According with previous data, resistance to SSA treatment might be due to heterogeneity in somatostatin receptors (SSTRs) expression. We report the case of TSHoma in a 41-year-old man treated with octreotide LAR that caused a dramatic decrease of TSH and thyroid hormones and tumor shrinkage already after 3 months of pre-surgical therapy. In search of potential molecular determinants of octreotide effectiveness, we measured, in primary cultures from this tumor, SSTR and dopamine D2 receptor (D2R) expression, and octreotide and/or cabergoline effects on TSH secretion and cell proliferation. SSTR5 and D2R expression was higher than SSTR2. Octreotide significantly inhibited TSH secretion more effectively than cabergoline (P<0.001), whereas the combined treatment was comparable with cabergoline alone. Similarly, octreotide resulted more effective than cabergoline on cell proliferation, while the combination did not show any additive or synergistic effects. In conclusion, the significant antisecretive and antiproliferative effect of octreotide in this patient might be related to the high expression of SSTR5, in the presence of SSTR2. After reviewing the literature, indeed, in line with previous observations, we hypothesize that SSTR5/SSTR2 ratio in TSHomas may represent a useful marker in predicting the outcome of therapy with SSAs. The role of D2R should be further explored considering that the presence of D2R can influence SSTRs functionality.

Short term effects of levothyroxine treatment in thyroid multinodular disease

The levothyroxine suppressive efficacy in benign thyroid nodules treatment is well described in uninodular non-toxic goiter, whereas only few controlled trials enrolled patients with multinodular disease. The aim of the present study is to evaluate the short term effects of levothyroxine treatment in never treated, pre-menopausal women affected by thyroid multinodular disease. Seventy-one pre-menopausal women with thyroid multinodular disease, still presenting normal TSH levels, from Latina area were randomly assigned to a levothyroxine treated or control group. Biochemical and ultrasonography evaluations of thyroid were monitored at the enrollment and after 6, 12 and 24 months of treatment. In the levothyroxine treated group, after 1 year of treatment, thyroid and dominant nodule volume and number of nodules >0.5 mL significantly decreased from a median of 12.0 to 9.8 mL (p <0.001), from 1.0 to 0.5 mL (p <0.001) and from 0.5 to 0, respectively. Conversely, in the control group significant augmented values of these parameters were observed (p =0.007, p <0.001 and p <0.001, respectively). Furthermore, these observations were also confirmed by results obtained after a 24 months follow-up period. Our data support previous observations on the clinical usefulness of L-T(4) treatment in preventing thyroid and nodule volume and nodule numbers growth. These findings confirm the tendency of benign nodular disease toward progression and the efficacy of TSH suppression in preventing its evolution by means of removing the major growth factor for thyroid nodules still responsive to physiological stimuli.

[An integrated model for the evaluation and risk management of tuberculosis infection and active tuberculosis in homeless people in the city of Rome (Italy)]

In this article we describe an integrated model for the evaluation and risk management of tuberculosis (TB) infection and active TB in socially disadvantaged populations in the city of Rome. We describe and discuss the clinical evaluation procedures performed and the data collection forms used; these tools are useful for the epidemiologic surveillance and clinical management of patients, particularly high risk patients such as the homeless.