Biological activity of ruthenium nitrosyl complexes

Nitric oxide plays an important role in various biological processes, such as neurotransmission, blood pressure control, immunological responses, and antioxidant action. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO-carriers. Coordination compounds, in particular ruthenium(III) and (II) amines, are good NO-captors and -deliverers. The chemical and photochemical properties of several ruthenium amine complexes as NO-carriers in vitro and in vivo have been reviewed. These nitrosyl complexes can stimulate mice hippocampus slices, promote the lowering of blood pressure in several in vitro and in vivo models, and control Trypanosoma cruzi and Leishmania major infections, and they are also effective against tumor cells in different models of cancer. These complexes can be activated chemically or photochemically, and the observed biological effects can be attributed to the presence of NO in the compound. Their efficiencies are explained on the basis of the [Ru^IINO⁺]³⁺/[Ru^IINO⁰]²⁺ reduction potential, the specific rate constant for NO liberation from the [RuNO]²⁺ moiety, and the quantum yield of NO release.     

Differences in the Detection of BrdU/EdU Incorporation Assays Alter the Calculation for G1, S,and G2 Phases of the Cell Cycle in Trypanosomatids

Trypanosomatids are the etiologic agents of various infectious diseases in humans. They diverged early during eukaryotic evolution and have attracted attention as peculiar models for evolutionary and comparative studies. Here, we show a meticulous study comparing the incorporation and detection of the thymidine analogs BrdU and EdU in Leishmania amazonensis, Trypanosoma brucei, and Trypanosoma cruzi to monitor their DNA replication. We used BrdU‐ and EdU‐incorporated parasites with the respective standard detection approaches: indirect immunofluorescence to detect BrdU after standard denaturation (2 M HCl) and “click” chemistry to detect EdU. We found a discrepancy between these two thymidine analogs due to the poor detection of BrdU, which is reflected on the estimative of the duration of the cell cycle phases G1, S, and G2. To solve this discrepancy, we increase the exposure of incorporated BrdU using different concentrations of HCl. Using a new value for HCl concentration, we re‐estimated the phases G1, S, G2 + M, and cytokinesis durations, confirming the values found by this approach using EdU. In conclusion, we suggest that the studies using BrdU with standard detection approach, not only in trypanosomatids but also in others cell types, should be reviewed to ensure an accurate estimation of DNA replication monitoring.     

The renin-angiotensin system in hypothyroidism of short duration

In six hypothyroid patients (2 male, 4 females, ages 22 through 59 years), plasma renin activity (PRA) and aldosterone (Aldo) were measured when the patients were euthyroid on levothyroxine therapy and one month after the therapy was stopped. Colonic mucosal potential differences were measured during the hypothyroid and euthyroid stages, and catecholamine sensitivity was determined by the blood pressure response to infused norepinephrine. Significant differences were observed in the PRA and aldosterone concentrations which were 4.1 +/- 2.5 ng/ml/h and 9.4 +/- 5.9 ng/dl, respectively in the hypothyroid stage and 6.9 +/- 2.3 ng/ml/h and 15.2 +/- 7.3 ng/dl, respectively when the patients were made euthyroid. The colonic mucosal potential differences (which reflect increased endogenous mineralocorticoid activity), became more electronegative after correction of hypothyroidism (-16.8 +/- 7.5 mV vs -32 +/- 18.2 mV; P less than 0.04) concentrations. Statistically significant decreases in norepinephrine pressor effects were observed in hypothyroid patients when compared to the euthyroid state (7.4 +/- 2.3 vs 10.9 +/- 1.9 micrograms/ng/min; P less than 0.01). It is concluded that patients with hypothyroidism have a hormonal pattern reminiscent of "low renin hypertension", and exhibit decreased sensitivity to catecholamines. Such changes are corrected when the patients become euthyroid on levothyroxine therapy.     

Morinda lucida reduces contractility of isolated uterine smooth muscle of pregnant and non-pregnant mice.

The present work investigated the effect of Morinda lucida (M. lucida) extract on isolated uterine smooth muscle of pregnant and non-pregnant mice. Pregnant and non-pregnant mice were pretreated with oral stilboesterol (0.1 mg/kg body weight) and killed by cervical dislocation. Thin strips of the uterus were cut and mounted in a 20ml organ bath containing De Jalon solution bubbled with 95%O2-5% CO2 gas mixture. The strips were connected to a force transducer coupled to a Grass 7D Polygraph for the recording of isometric tension. Effects of graded concentrations of oxytocin (OXY; 10-5-10-2 mol/L), acetylcholine (ACh; 10-9-10-5 mol/L) and M. lucida extract (0.015-1.5 mg/ml) were recorded. Fresh uterine strips were then incubated with M. lucida extract for 5mins and cumulative response to OXY was repeated. Another set of fresh strips was incubated in L-NAME for 15mins and the cumulative responses to M.lucida extract were repeated. OXY resulted in increased contractile responses in both pregnant and non-pregnant uterine muscles. M. lucida resulted in relaxation of the uterine smooth muscle in both pregnant and non-pregnant mice at all doses. However, at 1.5mg/ml, M. lucida completely blocked spontaneous uterine contractions. Following incubation with L-NAME, M. lucida extract led to a slightly greater relaxation of the uterine strips. In conclusion, M. lucida reduced contractility of uterine smooth muscle in both pregnant and non-pregnant mice as well as blocking contractile responses to OXY and Ach in uterine smooth muscle of pregnant and non-pregnant mice. There was no significant alteration of M. lucida activity by L-NAME suggesting that the action of the compound on uterine muscle is not associated with impaired nitric oxide synthase.     

Contrasting patterns of Andean diversification among three diverse clades of Neotropical clearwing butterflies

The Neotropical region is the most biodiverse on Earth, in a large part due to the highly diverse tropical Andean biota. The Andes are a potentially important driver of diversification within the mountains and for neighboring regions. We compared the role of the Andes in diversification among three subtribes of Ithomiini butterflies endemic to the Neotropics, Dircennina, Oleriina, and Godyridina. The diversification patterns of Godyridina have been studied previously. Here, we generate the first time‐calibrated phylogeny for the largest ithomiine subtribe, Dircennina, and we reanalyze a published phylogeny of Oleriina to test different biogeographic scenarios involving the Andes within an identical framework. We found common diversification patterns across the three subtribes, as well as major differences. In Dircennina and Oleriina, our results reveal a congruent pattern of diversification related to the Andes with an Andean origin, which contrasts with the Amazonian origin and multiple Andean colonizations of Godyridina. In each of the three subtribes, a clade diversified in the Northern Andes at a faster rate. Diversification within Amazonia occurred in Oleriina and Godyridina, while virtually no speciation occurred in Dircennina in this region. Dircennina was therefore characterized by higher diversification rates within the Andes compared to non‐Andean regions, while in Oleriina and Godyridina, we found no difference between these regions. Our results and discussion highlight the importance of comparative approaches in biogeographic studies.     

Pulmonary type II cell hypertrophy and pulmonary lipoproteinosis are features of chronic IL-13 exposure

Interleukin (IL)-13, a key mediator of Th2-mediated immunity, contributes to the pathogenesis of asthma and other pulmonary diseases via its ability to generate fibrosis, mucus metaplasia, eosinophilic inflammation, and airway hyperresponsiveness. In these studies, we compared surfactant accumulation in wild-type mice and mice in which IL-13 was overexpressed in the lung. When compared with littermate controls, transgenic animals showed alveolar type II cell hypertrophy under light and electron microscopy. Over time, their alveoli also filled with surfactant in a pulmonary alveolar proteinosis pattern. At the same time, prominent interstitial fibrosis occurs. Bronchoalveolar lavage fluid from these mice had a three- to sixfold increase in surfactant phospholipids. Surfactant proteins (SP)-A, -B, and -C showed two- to threefold increases, whereas SP-D increased 70-fold. These results indicate that IL-13 is a potent stimulator of surfactant phospholipid and surfactant accumulation in the lung. IL-13 may therefore play a central role in the broad range of chronic pulmonary conditions in which fibrosis, type II cell hypertrophy, and surfactant accumulation occur.     

Growth characteristics of Protoheliolites norvegicus (Tabulata; Upper Ordovician; Estonia)

Protoheliolites is an early heliolitine coral characterized by closely spaced corallites separated in places by sparse coenenchyme. Growth characteristics in the type species, P. norvegicus, are revealed by detailed analysis based on serial peels and thin sections of coralla from the uppermost Katian of north‐western Estonia. Colonies of this species had a strong ability to recover from damage and partial mortality, resulting in various forms of rejuvenation, regeneration, fusion and reorganization of corallites; in some cases, this involved relatively large areas of undifferentiated soft parts. The shells of commensal cornulitids became enclosed in host coralla during colony growth. Coralla of P. norvegicus exhibit distinctive growth cycles due to responses to seasonal changes. The production of new corallites by coenenchymal increase usually occurred in low‐density bands, in which corallites generally display round to subrounded transverse outlines. In high‐density bands, the corallites became crenulated, their wall thickness increased, septal development was more pronounced, and the amount of coenenchyme increased. In addition to these cyclomorphic changes, there were significant astogenetic changes during growth. Compared with the early stage of colony development, distinctive characteristics in the late astogenetic stage include a decrease in the growth rate of the colony, better coordination among corallites, maximum development of corallite crenulations and septa in high‐density bands, more numerous coenenchymal tubules and a greater proportion of corallum area occupied by coenenchyme. In general, the role of polyps in determining morphological characteristics of individual corallites, such as tabularium area, corallite crenulations and wall thickness, was subordinate to the astogeny of the colony. Growth characteristics including colony‐wide coordination of polyp behaviour and subjugation of individuals to restore the colony following damage suggest a strong astogenetic control and high level of colony integration. Protoheliolites probably arose from a heliolitine genus rather than from a nonheliolitine group as some authors have proposed.     

Developmental differences in the responses of IL-6 and IL-13 transgenic mice exposed to hyperoxia

Our previous work has shown that adult mice with overexpression of IL-6 and IL-13 in the lung have enhanced survival in hyperoxia associated with reduced hyperoxia-induced lung injury and cell death. We hypothesized that there are developmental differences in these responses in the adult vs. the newborn (NB) animal, and these responses have clinical relevance in the human NB. We compared the responses to 100% O(2) of NB IL-6 and IL-13 transgenic mice with wild-type littermate controls by evaluating mortality, lung tissue TUNEL staining, and mRNA expression using RT-PCR. We used ELISA to measure IL-6 levels in tracheal aspirates from human neonates. Our results show that, in contrast to the cytoprotective effects in mature mice, IL-6 caused significantly increased mortality, DNA injury, caspases, cell death regulator and angiogenic factor expression in hyperoxia in the NB. Furthermore, tracheal aspirate levels of IL-6 were significantly increased in premature neonates with respiratory distress syndrome who had an adverse outcome (bronchopulmonary dysplasia/death). In contrast to the protective effects in adults, there was no survival advantage to the NB IL-13 mice in hyperoxia. These findings imply that caution should be exercised in extrapolating results from the adult to the NB.