Coupling the core of the anticancer drug etoposide to an oligonucleotide induces topoisomerase II-mediated cleavage at specific DNA sequences.

Etoposide and other topoisomerase II-targeted drugs are important anticancer therapeutics. Unfortunately, the safe usage of these agents is limited by their indiscriminate induction of topoisomerase II-mediated DNA cleavage throughout the genome and by a lack of specificity toward cancer cells. Therefore, as a first step toward constraining the distribution of etoposide-induced DNA cleavage sites and developing sequence-specific topoisomerase II-targeted anticancer agents, we covalently coupled the core of etoposide to oligonucleotides centered on a topoisomerase II cleavage site in the PML gene. The initial sequence used for this 'oligonucleotide-linked topoisomerase inhibitor' (OTI) was identified as part of the translocation breakpoint of a patient with acute promyelocytic leukemia (APL). Subsequent OTI sequences were derived from the observed APL breakpoint between PML and RARA. Results indicate that OTIs can be used to direct the sites of etoposide-induced DNA cleavage mediated by topoisomerase IIα and topoisomerase IIß. OTIs increased levels of enzyme-mediated cleavage by inhibiting DNA ligation, and cleavage complexes induced by OTIs were as stable as those induced by free etoposide. Finally, OTIs directed against the PML-RARA breakpoint displayed cleavage specificity for oligonucleotides with the translocation sequence over those with sequences matching either parental gene. These studies demonstrate the feasibility of using oligonucleotides to direct topoisomerase II-mediated DNA cleavage to specific sites in the genome.

[Telestroke in Chile: 1 year experience at 7 hospitals]. / Telestroke en Chile: resultados de 1 año de experiencia de la Unidad de TeleACV del Servicio de Salud Metropolitano Sur en 7 hospitales ejecutores.

BACKGROUND: Acute ischemic stroke (AIS) is one of the leading causes of death in Chile. Intravenous thrombolysis (IVT) is an effective treatment. Geographical barriers and lack of specialists limit its application. Telemedicine can overcome some of these pitfalls. AIM: To describe the implementation and results of AIS treatment by telemedicine at the TeleStroke Unit (TeleACV) of the Southern Metropolitan Health Service, connected with seven hospitals in Chile. MATERIAL AND METHODS: Descriptive analysis of a prospective tele-thrombolysis data-base that covers from 2016 to 2018, with an emphasis in the last year. RESULTS: During the analyzed period, seven remote telemedicine centers were activated as far as 830 kilometers on a continental level from the reference center and up to 3,700 kilometers on an island level. There were 1,024 telemedicine consultations, 144 (14%) of them resulted in an IVT treatment. During 2018, 597 tele-consultations were made, thrombolysis was done in 115 (19%) patients aged 66+-13 years; 54 (46.6%) being female. The median admission National Institute of Health Stroke Scale was 8 (interquartile range (IQR) 5-14). The median door-to-needle time was 56.5 (IQR 44.8-73.3) minutes; 60% of patients were treated within 60 minutes. Eight patients (7%) were referred for a subsequent mechanical thrombectomy to a center of greater complexity. Symptomatic intra-cranial hemorrhages occurred in four treated patients (4%). One patient had a systemic bleeding. CONCLUSIONS: The Telestroke Unit achieved a high rate of IVT and good door-to-needle times. This may help to overcome some of the geographic barriers and the specialist availability gap in our country.

Novel trifluoromethylated 9-amino-3,4-dihydroacridin-1(2H)-ones act as covalent poisons of human topoisomerase IIα.

A number of topoisomerase II-targeted anticancer drugs, including amsacrine, utilize an acridine or related aromatic core as a scaffold. Therefore, to further explore the potential of acridine-related compounds to act as topoisomerase II poisons, we synthesized a series of novel trifluoromethylated 9-amino-3,4-dihydroacridin-1(2H)-one derivatives and examined their ability to enhance DNA cleavage mediated by human topoisomerase IIα. Derivatives containing a H, Cl, F, and Br at C7 enhanced enzyme-mediated double-stranded DNA cleavage ∼5.5- to 8.5-fold over baseline, but were less potent than amsacrine. The inclusion of an amino group at C9 was critical for activity. The compounds lost their activity against topoisomerase IIα in the presence of a reducing agent, displayed no activity against the catalytic core of topoisomerase IIα, and inhibited DNA cleavage when incubated with the enzyme prior to the addition of DNA. These findings strongly suggest that the compounds act as covalent, rather than interfacial, topoisomerase II poisons.

Isolation and structural elucidation of antiproliferative compounds of lipidic fractions from white shrimp muscle (Litopenaeus vannamei).

Shrimp is one of the most popular seafood items worldwide, and has been reported as a source of chemopreventive compounds. In this study, shrimp lipids were separated by solvent partition and further fractionated by semi-preparative RP-HPLC and finally by open column chromatography in order to obtain isolated antiproliferative compounds. Antiproliferative activity was assessed by inhibition of M12.C3.F6 murine cell growth using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay. The methanolic fraction showed the highest antiproliferative activity; this fraction was separated into 15 different sub-fractions (M1-M15). Fractions M8, M9, M10, M12, and M13 were antiproliferative at 100 µg/mL and they were further tested at lower concentrations. Fractions M12 and M13 exerted the highest growth inhibition with an IC50 of 19.5 ± 8.6 and 34.9 ± 7.3 µg/mL, respectively. Fraction M12 was further fractionated in three sub-fractions M12a, M12b, and M12c. Fraction M12a was identified as di-ethyl-hexyl-phthalate, fraction M12b as a triglyceride substituted by at least two fatty acids (predominantly oleic acid accompanied with eicosapentaenoic acid) and fraction M12c as another triglyceride substituted with eicosapentaenoic acid and saturated fatty acids. Bioactive triglyceride contained in M12c exerted the highest antiproliferative activity with an IC50 of 11.33 ± 5.6 µg/mL. Biological activity in shrimp had been previously attributed to astaxanthin; this study demonstrated that polyunsaturated fatty acids are the main compounds responsible for antiproliferative activity.

Nutrient Removal by Grain in Modern Soybean Varieties.

Knowing the nutrient removal by soybean grain harvest in different varieties, locations, and over time is essential to correctly adjust agronomic recommendations, update farmers' practices, and increase nutrient use efficiency. A field-based research trial was carried out to assess macronutrients [nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), and sulfur (S)] removed in grain by modern soybean varieties from southern Brazil introduced between 2007 and 2016. We examined changes between our set of modern varieties and a dataset of historical values encompassing a wide range of varieties introduced before 2007. Moreover, we undertook a synthesis analysis using scientific literature published after 2007 to investigate nutrient removal by grain among modern Brazilian soybeans and a dataset that included field trials from Argentina, United States, and India. There were no yield gains across the years for modern soybean varieties introduced among 2007 and 2016 in Brazil, although the grain N and Mg concentrations decreased. Modern Brazilian soybeans increased nutrient removal compared with that by soybeans historically planted in Brazil, with 11.1, 26.9, 45.0, and 31.6% more N, P, K, and Mg removed, respectively. Our results indicated that soybean growing in Brazil removed 4.3% less N relative to the values reported in the literature dataset, whereas K removal was 21.4% greater. A significant difference was also recorded for high-yield soybean varieties, and Brazilian varieties removed 11.8% less N and 8.6% more K than varieties in the literature dataset. No differences were found among locations for P removal, averaging 4.9 kg Mg-1 grain. In conclusion, this study indicates that the amounts of nutrients removed by modern soybean varieties were greater relative to the historical values recorded in Brazil, excluding Ca and S. Nonetheless, in the middle to long term (10 years), a significant impact of plant breeding on grain nutrient concentration was recorded only for N and Mg. The difference in nutrient removal patterns between Brazil and other countries indicates an integrated effect of management, genotype, and environment on nutrient removal. These findings provide guidance for optimal nutrient management and specific information for plant breeding programs to understand nutrient variability.

Antimutagenicity and antiproliferative studies of lipidic extracts from white shrimp (Litopenaeus vannamei).

An organic extract from fresh shrimp (Litopenaeus vannamei) was studied for antimutagenic and antiproliferative properties using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. Shrimp extract was sequentially fractionated by thin layer chromatography (TLC) and each fraction was tested for antimutagenic and antiproliferative activities. Crude organic extracts obtained from shrimp reduced the number of revertants caused by aflatoxina B(1), showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. These results suggested that the lipid fraction of the tested species contained compounds with chemoprotective properties that reduce the mutagenicity of AFB(1) and proliferation of a cancer cell line.

Antimutagenic Compounds of White Shrimp (Litopenaeus vannamei): Isolation and Structural Elucidation.

According to the World Health Organization, cancer is the main cause of mortality worldwide; thus, the search of chemopreventive compounds to prevent the disease has become a priority. White shrimp (Litopenaeus vannamei) has been reported as a source of compounds with chemopreventive activities. In this study, shrimp lipids were extracted and then fractionated in order to isolate those compounds responsible for the antimutagenic activity. The antimutagenic activity was assessed by the inhibition of the mutagenic effect of aflatoxin B1 on TA98 and TA100 Salmonella tester strains using the Ames test. Methanolic fraction was responsible for the highest antimutagenic activity (95.6 and 95.9% for TA98 and TA100, resp.) and was further separated into fifteen different subfractions (M1-M15). Fraction M8 exerted the highest inhibition of AFB1 mutation (96.5 and 101.6% for TA98 and TA100, resp.) and, after further fractionation, four subfractions M8a, M8b, M8c, and M8d were obtained. Data from (1)H and (13)C NMR, and mass spectrometry analysis of fraction M8a (the one with the highest antimutagenic activity), suggest that the compound responsible for its antimutagenicity is an apocarotenoid.

Telestroke en Chile: resultados de 1 año de experiencia de la Unidad de TeleACV del Servicio de Salud Metropolitano Sur en 7 hospitales ejecutores / Telestroke in Chile: 1 year experience at 7 hospitals

Background: Acute ischemic stroke (AIS) is one of the leading causes of death in Chile. Intravenous thrombolysis (IVT) is an effective treatment. Geographical barriers and lack of specialists limit its application. Telemedicine can overcome some of these pitfalls. Aim: To describe the implementation and results of AIS treatment by telemedicine at the TeleStroke Unit (TeleACV) of the Southern Metropolitan Health Service, connected with seven hospitals in Chile. Material and Methods: Descriptive analysis of a prospective tele-thrombolysis data-base that covers from 2016 to 2018, with an emphasis in the last year. Results: During the analyzed period, seven remote telemedicine centers were activated as far as 830 kilometers on a continental level from the reference center and up to 3,700 kilometers on an island level. There were 1,024 telemedicine consultations, 144 (14%) of them resulted in an IVT treatment. During 2018, 597 tele-consultations were made, thrombolysis was done in 115 (19%) patients aged 66+-13 years; 54 (46.6%) being female. The median admission National Institute of Health Stroke Scale was 8 (interquartile range (IQR) 5-14). The median door-to-needle time was 56.5 (IQR 44.8-73.3) minutes; 60% of patients were treated within 60 minutes. Eight patients (7%) were referred for a subsequent mechanical thrombectomy to a center of greater complexity. Symptomatic intra-cranial hemorrhages occurred in four treated patients (4%). One patient had a systemic bleeding. Conclusions: The Telestroke Unit achieved a high rate of IVT and good door-to-needle times. This may help to overcome some of the geographic barriers and the specialist availability gap in our country.

Bioactive Lipidic Extracts from Octopus (Paraoctopus limaculatus): Antimutagenicity and Antiproliferative Studies.

Fractions from an organic extract from fresh octopus (Paraoctopus limaculatus) were studied for biological activities such as antimutagenic and antiproliferative properties using Salmonella tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. A chloroform extract obtained from octopus tentacles was sequentially fractionated using thin layer chromatography (TLC), and each fraction was tested for antimutagenic and antiproliferative activities. Organic extract reduced the number of revertants caused by aflatoxin B(1) showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. Based on the results obtained, the isolated fractions obtained from octopus contain compounds with chemoprotective properties that reduce the mutagenicity of AFB(1) and proliferation of cancer cell lines.