The pentadehydro-Diels-Alder reaction.

In the classic Diels-Alder [4 + 2] cycloaddition reaction, the overall degree of unsaturation (or oxidation state) of the 4π (diene) and 2π (dienophile) pairs of reactants dictates the oxidation state of the newly formed six-membered carbocycle. For example, in the classic Diels-Alder reaction, butadiene and ethylene combine to produce cyclohexene. More recent developments include variants in which the number of hydrogen atoms in the reactant pair and in the resulting product is reduced by, for example, four in the tetradehydro-Diels-Alder (TDDA) and by six in the hexadehydro-Diels-Alder (HDDA) reactions. Any oxidation state higher than tetradehydro (that is, lacking more than four hydrogens) leads to the production of a reactive intermediate that is more highly oxidized than benzene. This increases the power of the overall process substantially, because trapping of the reactive intermediate can be used to increase the structural complexity of the final product in a controllable and versatile manner. Here we report an unprecedented overall 4π + 2π cycloaddition reaction that generates a different, highly reactive intermediate known as an α,3-dehydrotoluene. This species is in the same oxidation state as a benzyne. Like benzynes, α,3-dehydrotoluenes can be captured by various trapping agents to produce structurally diverse products that are complementary to those arising from the HDDA process. We call this new cycloisomerization process a pentadehydro-Diels-Alder (PDDA) reaction-a nomenclature chosen for chemical taxonomic reasons rather than mechanistic ones. In addition to alkynes, nitriles (RC≡N), although non-participants in aza-HDDA reactions, readily function as the 2π component in PDDA cyclizations to produce, via trapping of the α,3-(5-aza)dehydrotoluene intermediates, pyridine-containing products.

The Aza-hexadehydro-Diels-Alder Reaction.

The generation of pyridynes from diyne nitriles is reported. These cyano-containing precursors are analogues of the triyne substrates typically used for the hexadehydro-Diels-Alder (HDDA) cycloisomerization reactions that produce ring-fused benzynes. Hence, the new processes described represent aza-HDDA reactions. Depending on the location of the nitrile, either 3,4-pyridynes (from 1,3-diynes containing a tethered cyano group) or 2,3-pyridynes (from 1-cyanoethyne derivatives containing a tethered alkyne) are produced. In situ trapping of these reactive intermediates leads to highly substituted and functionalized pyridine derivatives. In several instances, unprecedented pyridyne trapping reactions are seen. Differences in reaction energetics between the aza-HDDA substrates and that of their analogous HDDA (triyne) substrates are discussed.

Supramolecular gels based on boronate esters and imidazolyl donors.

Dative boron-nitrogen bonds can be used for the controlled assembly of boronate esters and N-donor ligands. So far, most investigations have focused on crystalline assemblies. In contrast, there are very few reports about soft materials based on dative B-N bonds. Here, we describe the formation of gels by aggregation of diboronate esters and ditopic bisimidazolyl donor ligands. Analyses of low molecular weight model compounds by NMR spectroscopy, isothermal titration calorimetry, and X-ray crystallography reveal that imidazolyl ligands form particularly strong dative bonds with boronate esters. The strong interaction allows gel formation in competitive polar solvents such as THF and acetone. In less polar solvents, very low critical gel concentrations of down to 0.02 wt% are observed. By using a diboronate ester linked by an azobenzene group, it is possible to form a photoresponsive gel.

Tissue fatty acid composition and estimated ∆ desaturase activity after castration in chicken broilers fed with linseed or sunflower oil.

The aims of this study were to investigate the influence of the short-term addition of sunflower and linseed oil and castration on fatty acid composition and desaturation indexes in chicken broilers. Forty-eight male Ross 308 chicken broilers were supplemented with 5% of sunflower or linseed oil. The four experimental groups were linseed oil supplementation and castration (LC), linseed oil without castration (LN), sunflower oil and castration (SC) and sunflower oil without castration (SN). There was no significant influence of castration or oil supplement on live weights, weight gain, feed intake or feed conversion. Castration resulted in an increase in polyunsaturated fatty acids (PUFA), total n3, n6, measured desaturation indexes and a decrease in the saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) content of abdominal fat. In breast muscle, castration increased PUFA and 18:3n3 values, while in the liver tissue, castration did not influence the parameters measured. Linseed oil supplementation significantly increased 18:3n3, n3 long chain polyunsaturated fatty acids (LC PUFA), total n3 and decreased total n6, n6/n3 ratio, and 20:4n6 content. Values for 20:4n6 were the highest in SC and the lowest in the LC group. Linseed oil also significantly decreased ∆5 and ∆4 desaturation indexes in the thighs and ∆5 and ∆5, 6 in abdominal fat and the liver. These results suggest that short-term supplementation of basal diet with 5% of linseed oil could significantly increase n3 LC PUFA and decrease n6/n3 ratio content in the edible tissues of chicken broilers, without adverse effects on growth performance. Meanwhile, castration only improved fatty acid profile in abdominal fat, which is not nutritionally important. The interactions observed between basal diet, supplemented oil, sex hormones and other non-nutritional factors must be elucidated in future trials in order to correctly predict the nutritional value of linseed-fed poultry.

Towards imaging the immune state of cancer by PET: Targeting legumain with 11C-labeled P1-Asn peptidomimetics carrying a cyano-warhead.

PURPOSE: M2-type tumor-associated macrophages (TAM) residing in the tumor microenvironment (TME) have been linked to tumor invasiveness, metastasis and poor prognosis. M2 TAMs suppress T cell activation, silencing the recognition of the cancer by the immune system. Targeting TAMs in anti-cancer therapy may support the immune system and immune-checkpoint inhibitor therapies to fight the cancer cells. We aimed to develop a PET tracer for the imaging of M2 TAM infiltration of cancer, using activated legumain as the imaging target. BASIC PROCEDURES: Two P1-mimicking inhibitors with a cyano-warhead were labeled with carbon-11 and evaluated in vitro and in vivo with a CT26 tumor mouse model. Target expression and activity were quantified from RT-qPCR and in vitro substrate conversion, respectively. The co-localization of legumain and TAMs was assessed by fluorescence microscopy. The two tracers were evaluated by PET with subsequent biodistribution analysis with the dissected tissues. Parent-to-total radioactivity in plasma was determined at several time points after i.v. tracer injection, using reverse phase radio-UPLC. MAIN FINDINGS: Legumain displayed a target density of 40.7 ± 19.1 pmol per mg total protein in tumor lysate (n = 4) with high substrate conversion and colocalization with M2 macrophages in the tumor periphery. [11C]1 and [11C]2 were synthesized with >95 % radiochemical purity and 12.9-382.2 GBq/µmol molar activity at the end of synthesis. We observed heterogeneous tumor accumulation in in vitro autoradiography and PET for both tracers. However, excess unlabeled 1 or 2 did not compete with tracer accumulation. Both [11C]1 and [11C]2 were rapidly metabolized to a polar radiometabolite in vivo. PRINCIPAL CONCLUSIONS: The legumain tracers [11C]1 and [11C]2, synthesized with high radiochemical purity and molar activity, accumulate in the legumain-positive CT26 tumor in vivo. However, the lack of competition by excess compound questions their specificity. Both tracers are rapidly metabolized in vivo, requiring structural modifications towards more stable tracers for further investigations.

Variability in disease burden and management of rheumatic fever and rheumatic heart disease in two regions of tropical Australia.

BACKGROUND: Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) contribute to Aboriginal Australian and Torres Strait Islander health disadvantage. At the time of this study, specialist ARF/RHD care in the Kimberley region of Western Australia was delivered by a broad range of providers. In contrast, in Far North Queensland (FNQ), a single-provider model was used as part of a coordinated RHD control programme. AIMS: To review ARF/RHD management in the Kimberley and FNQ to ascertain whether differing models of service delivery are associated with different disease burden and patient care. METHODS: An audit of ARF/RHD management. Classification and clinical management data were abstracted from health records, specialist letters, echocardiograms and regional registers using a standardised data collection tool. RESULTS: Four hundred and seven patients were identified, with 99% being Aboriginal and/or Torres Strait Islanders. ARF without RHD was seen in 0.4% of Aboriginal and/or Torres Strait Islander residents and RHD in 1.1%. The prevalence of RHD was similar in both regions but with more severe disease in the Kimberley. More FNQ RHD patients had specialist review within recommended time frames (67% vs 45%, χ(2) , P < 0.001). Of patients recommended benzathine penicillin secondary prophylaxis, 17.7% received ≥80% of scheduled doses in the preceding 12 months. Prescription and delivery of secondary prophylaxis was greater in FNQ. CONCLUSIONS: FNQ's single-provider model of specialist care and centralised RHD control programme were associated with improved patient care and may partly account for the fewer cases of severe disease and reduced surgical procedures and other interventions observed in this region.

Liver enzymes and blood metabolites in a population of free-ranging red deer (Cervus elaphus) naturally infected with Fascioloides magna.

We investigated the effects of Fascioloides magna infection on the serum biochemistry values of the naturally infected red deer population in eastern Croatia. The investigation was performed on 47 red deer with F. magna infection confirmed patho-anatomically in 27 animals (57.4%). Fibrous capsules and migratory lesions were found in 14 deer while only fibrous capsules without migratory lesions were found in 13 deer. In 13 deer both immature and mature flukes were found, in 5 deer only immature flukes were found and in 9 deer only mature flukes were found. Fascioloides magna infected deer with fibrous capsules and migratory lesions had significantly higher values for lactate dehydrogenase (LDH), glutamate dehydrogenase (GLDH) and globulin, and lower values for albumin/globulin ratio and glucose compared to uninfected deer. Fascioloides magna infected deer with fibrous capsules without the presence of migratory lesions had higher values for alanine aminotransferase (ALT) and globulin, and lower values for albumin/globulin ratio and glucose, than the uninfected deer. The number of immature flukes was positively correlated with values of aspartate aminotransferase (AST), γ-glutamyltransferase (GGT), LDH, GLDH, urea and triglycerides. The number of migratory lesions was positively correlated with GGT, GLDH, globulin and urea values. The creatinine value was positively correlated with the number of mature flukes. The trial showed that F. magna infection causes significant changes in serum biochemistry. Moreover, these changes do not completely resemble changes following F. hepatica infection. Further investigation of changes in liver enzymes and other serum metabolites in controlled, experimentally induced fascioloidosis in red deer is needed to better understand the pathogenesis of F. magna.

Small molecule Son of Sevenless 1 (SOS1) inhibitors: a review of the patent literature.

Introduction: Up to 30% of all human cancers are driven by the overactivation of RAS signaling. Son of Sevenless 1 (SOS1) is a central node in RAS signaling pathways and modulation of SOS1-mediated RAS activation represents a unique opportunity for treating RAS-addicted cancers. Several recent publications and patent documents have demonstrated the ability of small molecules to affect the activation of RAS by SOS1 and have shown their potential for the treatment of cancers driven by RAS mutants.Areas covered: Documents focusing on both small-molecule inhibitors and activators of the SOS1:RAS interaction and their potential use as cancer therapeutics are covered. A total of 10 documents from 4 applicants are evaluated with discussion focusing on structural modifications of these compounds as well as relevant preclinical data.Expert opinion: The last decade has seen a significant increase in research and disclosures in the development of small-molecule SOS1 inhibitors. Considering the promising data that have been disclosed, interest in this area of research will likely remain strong for the foreseeable future. With the first SOS1 inhibitor currently in phase I clinical trials, the outcome of these trials will likely influence future development of SOS1 inhibitors for treatment of RAS-driven cancers.

Quantification of morphology of canine circumanal gland tumors: a fractal based study.

Circumanal gland tumors are very common neoplasms of dogs. Their classification relies on microscopic examination and is further supported by a few immunohistochemical markers that help indicate their prognosis. However, new additional tests would be highly useful. The purpose of this study was to develop such a test using fractal analysis which is increasingly being applied in science, especially in the field of biomedicine. A total of 53 circumanal gland tumors were chosen from our department archives. After a precise histological classification according to the World Health Organization classification, the number of de novo classified samples was as follows: 15 adenomas, 11 epitheliomas, 21 well differentiated carcinomas, 6 poorly differentiated carcinomas. Ten samples of normal circumanal gland were also included as control. All samples were immunohistochemicaly stained with vimentin. All immunohistochemical reactions were photographed at two different magnifications -100X and 400X and converted to 1 bit in black and white (bitmap) images thus enhancing the positive vimentin reactions. These images were used for the assessment of fractal dimension applying the box counting method and computer software Fractalyse. To determine the significance of results, conventional statistics were performed using Statistica software. The overall vimentin stain score was significantly higher in epitheliomas and carcinomas than in normal circumanal glands (CG) or adenomas. Mean values of fractal dimension estimated at magnification 100X and 400X were as follows: normal CG 1.318 and 1.372, CG adenomas 1.384 and 1.408, CG epitheliomas 1.547 and 1.597, CG well differentiated carcinomas 1.569 and 1.607, CG poorly differentiated carcinomas 1.679 and 1.723. Significant differences (at level of 5%) of these values were observed between individual groups of CG adenomas or normal CG, and epitheliomas or carcinomas. The above results indicate vimentin immunohistochemistry staining and assessment of fractal dimension as an ancillary diagnostic method of choice when discerning between benign and malignant tumors of circumanal glands. Additional development of the method of fractal dimension assesment may yield a possibility for this tool to successfully discern between all of the types of CG tumors.

Diels-Alder Reactions of Furans with Itaconic Anhydride: Overcoming Unfavorable Thermodynamics.

Unfavorable thermodynamics often render furans reluctant to engage in high-yielding Diels-Alder (DA) cycloaddition reactions. Here, we report the highly efficient conversion of the biosourced reactants itaconic anhydride (IA) and furfuryl alcohol (FA) to a single DA adduct. The free energy advantages provided by anhydride ring opening and crystal lattice energy of the product overcome the loss of aromaticity of the furanoid diene. Detailed (1)H NMR studies provided valuable insights about relevant kinetic and thermodynamic features.

Imprinted polymers with transition metal catalysts.

The microenvironment of immobilized transition metal catalysts can be manipulated using catalyst-substrate conjugates in combination with the technology of molecular imprinting. Recent results have shown that catalysts with a significantly enhanced activity combined with an improved substrate-, regio- and enantioselectivity can be prepared in this way. These artificial systems resemble metalloenzymes because the catalytic transformation is effectively controlled by a well-defined second coordination sphere.

Autocatalytic networks: the transition from molecular self-replication to molecular ecosystems.

The transition from inanimate to animate chemistry is thought to involve self-organised networks of molecular species whose collective emergent property gives rise to the overall characteristics of living systems. In the past, simple autocatalytic networks have been constructed that display basic forms of cooperative behaviour. These include reciprocal catalysis, autocratic, and hypercyclic networks. The design and emergent properties of these novel molecular networks are reviewed here.

Monitoring and treatment of Fascioloides magna in semi-farm red deer husbandry in Croatia.

The presence of American liver fluke (Fascioloides magna) in Croatian wild ruminant species was detected for the first time in January 2000. At the same time, the problem of adequate parasitological monitoring and treatment appeared in the captive deer population. Quarantine and health screening protocols, as well as migration and transportation influence had to be evaluated in red deer husbandry. Non-invasive methods were introduced to estimate the prevalence of F. magna in the semi-farm rearing system. Coprological analysis has been performed on 264 faecal samples. The most effective antiparasitic treatment was implemented on herd and individual treatment. Treatment was extended to the free-ranging population of deer in the same region.

Ubiquinone biosynthesis. Cloning of the genes coding for chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyl transferase from Escherichia coli.

Chorismate pyruvate-lyase activity was detected in extracts of Escherichia coli. 4-Hydroxybenzoate was identified as the product of the enzymatic reaction by chemical derivatization and GC-MS analysis. The ubiC gene, coding for the chorismate pyruvate-lyase, was cloned and sequenced. The molecular weight of the gene product was calculated as 18,776 Da and confirmed by expression of the protein in E. coli minicells. The ubiA gene, coding for the 4-hydroxybenzoate octaprenyl transferase, was identified by sequence homology and complementation of a ubiA- strain. It is located directly downstream of ubiC in a typical operon structure.

A ruthenium porphyrin catalyst immobilized in a highly cross-linked polymer.

An immobilized Ru(meso-tetraarylporphyrin) complex was shown to be a very efficient catalyst for the epoxidation of olefins. In the presence of HBr, alcohols and even alkanes could be converted to the corresponding ketones. For the latter reactions the polymeric catalyst displayed a significantly enhanced activity when compared to that of the homogeneous version.[reaction: see text]

Effect of human and recombinant IFN-alpha and IFN-beta on the sister-chromatid exchange (SCE) frequency in amniotic fluid cells in vitro.

Sister-chromatid exchange (SCE) and rates of proliferation in human amniotic fluid cells from healthy donors exposed to human IFN-alpha and IFN-beta and recombinant IFN-alpha and -beta were investigated. Amniotic fluid cells were obtained from pregnant women undergoing genetic amniocentesis. For 46 h, cells were treated with IFNs at concentrations of 10(3)-10(5) U/l. A dose-depending decrease of SCE rate with IFN-alpha and IFN-beta was observed. Our studies in amniotic fluid cells show that the mean SCE frequencies are reduced after incubation with IFN-alpha as well as with IFN-alpha. In contrast to IFN-gamma, the type I IFNs IFN-alpha and IFN-beta cause a genetic effect on DNA repair or a protection from DNA damage. Previously we had shown that a significant dose-depending increase of SCE rates was found in amniotic fluid cultures after addition of IFN-gamma. Therefore, IFN-alpha and IFN-beta (both human IFNs) and also recombinant IFN-alpha and IFN-beta, also in high doses, are neither genotoxic/clastogenic nor embryotoxic. Amniotic cells are vulnerable human cells, which may be well suited for examining the effects of agents like interferon.

Chemically Triggered Assembly of Chiral Triangular Metallomacrocycles.

Self-assembly of chiral, half-sandwich complexes results in the formation of triangular metallomacrocycles under complete stereocontrol and in quantitative yields. The assembly-disassembly process can be triggered by the addition of acid or base (see scheme).

Hematological and biochemical changes in organically farmed sheep naturally infected with Fasciola hepatica.

A naturally occurring outbreak of fasciolosis in a group of 20 Merinolandschaf (German Merino) sheep was studied. Hematological and blood biochemical values in sheep spontaneously infected with liver fluke Fasciola hepatica were compared with equivalent values in 20 parasite-free sheep from organically farmed flock. Investigated animals were kept in outdoor system, on pastures covered with swamps, which remain flooded after rainy season. Significantly lower red blood cell (RBC) count, lymphocytes, hemoglobin (Hb), packed cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine, and albumin were recorded in sheep from the infected herd, whereas white blood cell (WBC) count, eosinophil, segmented and band neutrophil count, mean corpuscular volume (MCV), gamma-glutamyl transferase (GGT), concentrations of glucose, and globulins were significantly higher than in the parasite free herd. No significant correlation between the investigated blood parameters and the number of F. hepatica eggs in the feces was detected. This study shows that hematological and biochemical values can be useful in early diagnosis and prognosis of sheep fasciolosis.