Long-term Sonographic and Serological Follow-up of Inactive Echinococcal Cysts of the Liver: Hints for a “Watch-and-Wait” Approach

Human cystic echinococcosis is a chronic, complex and neglected infection. Its clinical management has evolved over decades without adequate evaluation of efficacy. Recent expert opinion recommends that uncomplicated inactive cysts of the liver should be left untreated and solely monitored over time (“watch-and-wait” approach). However, clinical data supporting this approach are still scant and published mostly as conference proceedings. In this study, we report our experience with long-term sonographic and serological follow-up of inactive cysts of the liver. From March 1994 to October 2013, 38 patients with 47 liver cysts, diagnosed as inactive without any previous treatment history, were followed with ultrasound and serology at 6–12 months intervals for a period of at least 24 months (median follow-up 51.95 months) in our outpatient clinic. In 97.4% of patients, the cysts remained inactive over time and in only one case was reactivation of the cyst detected. No complications occurred during the time of monitoring. During follow-up, serology tests for CE were negative at diagnosis or became negative in 74.1% and were positive or became positive in 25.9% of cases. Patients with inactive cysts on ultrasound but positive serological tests were also investigated by CT scan (chest and abdomen) to rule out extra-hepatic cyst localization. This study confirms the importance of a stage-specific approach to the management of cystic echinococcosis and supports the use of a monitoring-only approach to inactive, uncomplicated cysts of the liver. It also confirms that serology plays only an ancillary role in the clinical management of these patients, compared to ultrasound and other imaging techniques. The implications of these findings for clinical management and natural history of cystic echinococcosis are discussed.     

Metabolic Profiling of Alternative NAD Biosynthetic Routes in Mouse Tissues

NAD plays essential redox and non-redox roles in cell biology. In mammals, its de novo and recycling biosynthetic pathways encompass two independent branches, the “amidated” and “deamidated” routes. Here we focused on the indispensable enzymes gating these two routes, i.e. nicotinamide mononucleotide adenylyltransferase (NMNAT), which in mammals comprises three distinct isozymes, and NAD synthetase (NADS). First, we measured the in vitro activity of the enzymes, and the levels of all their substrates and products in a number of tissues from the C57BL/6 mouse. Second, from these data, we derived in vivo estimates of enzymes''rates and quantitative contributions to NAD homeostasis. The NMNAT activity, mainly represented by nuclear NMNAT1, appears to be high and nonrate-limiting in all examined tissues, except in blood. The NADS activity, however, appears rate-limiting in lung and skeletal muscle, where its undetectable levels parallel a relative accumulation of the enzyme''s substrate NaAD (nicotinic acid adenine dinucleotide). In all tissues, the amidated NAD route was predominant, displaying highest rates in liver and kidney, and lowest in blood. In contrast, the minor deamidated route showed higher relative proportions in blood and small intestine, and higher absolute values in liver and small intestine. Such results provide the first comprehensive picture of the balance of the two alternative NAD biosynthetic routes in different mammalian tissues under physiological conditions. This fills a gap in the current knowledge of NAD biosynthesis, and provides a crucial information for the study of NAD metabolism and its role in disease.     

Does elevated atmospheric CO2 concentrations affect wood decomposition?

This study was conducted to test the hypothesis that wood tissues generated under elevated atmospheric [CO₂] have lower quality and subsequent reduced decomposition rates. Chemical composition and subsequent field decomposition rates were studied for beech (Fagus sylvatica L.) twigs grown under ambient and elevated [CO₂] in open top chambers. Elevated [CO₂] significantly affected the chemical composition of beech twigs, which had 38% lower N and 12% lower lignin concentrations than twigs grown under ambient [CO₂]. The strong decrease in N concentration resulted in a significant increase in the C/N and lignin/N ratios of the beech wood grown at elevated [CO₂]. However, the elevated [CO₂] treatment did not reduce the decomposition rates of twigs, neither were the dynamics of N and lignin in the decomposing beech wood affected by the [CO₂] treatment, despite initial changes in N and lignin concentrations between the ambient and elevated [CO₂] beech wood. This revised version was published online in June 2006 with corrections to the Cover Date.     

Backbone dynamics and hydrogen exchange of Pseudomonas aeruginosa ferricytochrome c 551

A model-free analysis of Pseudomonas aeruginosa ferricytochrome c(551) dynamics based on (15)N R(1), (15)N R(2), and [(1)H]-(15)N heteronuclear nuclear Overhauser effect data is reported. The protein backbone is highly rigid (< S(2)>=0.924+/-0.005) and displays little variation in picosecond-nanosecond time scale dynamics over the structure. The loop structure containing the axial methionine ligand (loop 3) displays anomalous rigidity, which is attributed to its high proline content. Also reported are protection factors calculated from hydrogen-exchange rates. These data reveal that loop 3 residues, including the axial methionine, are protected from exchange as a result of long-range hydrogen-bonding interactions. These results are contrasted with data reported for Saccharomyces cerevisiae iso-1-ferricytochrome c, which displays higher overall flexibility (< S(2)>=0.80+/-0.07), greater variation of dynamics as a function of structure, and low protection factors for loop 3. This analysis reveals that heme proteins with similar functions and topologies may display diverse dynamical properties.     

Histone hyperacetylation in mitosis prevents sister chromatid separation and produces chromosome segregation defects

Posttranslational modifications of core histones contribute to driving changes in chromatin conformation and compaction. Herein, we investigated the role of histone deacetylation on the mitotic process by inhibiting histone deacetylases shortly before mitosis in human primary fibroblasts. Cells entering mitosis with hyperacetylated histones displayed altered chromatin conformation associated with decreased reactivity to the anti-Ser 10 phospho H3 antibody, increased recruitment of protein phosphatase 1-delta on mitotic chromosomes, and depletion of heterochromatin protein 1 from the centromeric heterochromatin. Inhibition of histone deacetylation before mitosis produced defective chromosome condensation and impaired mitotic progression in living cells, suggesting that improper chromosome condensation may induce mitotic checkpoint activation. In situ hybridization analysis on anaphase cells demonstrated the presence of chromatin bridges, which were caused by persisting cohesion along sister chromatid arms after centromere separation. Thus, the presence of hyperacetylated chromatin during mitosis impairs proper chromosome condensation during the pre-anaphase stages, resulting in poor sister chromatid resolution. Lagging chromosomes consisting of single or paired sisters were also induced by the presence of hyperacetylated histones, indicating that the less constrained centromeric organization associated with heterochromatin protein 1 depletion may promote the attachment of kinetochores to microtubules coming from both poles.     

Designing a “tailor-made” ecological network using geographical information systems

During the last few years, geographical information systems (GIS) have spread as powerful tools for landscape analysis. The main purpose of this work was to use GIS to display an ecological network made up of core areas, key areas and ecological corridors. As an example of the application of this method we refer to the population of deer (Cervus elaphus) and roe deer (Capreolus capreolus) in an alpine area in northwestern Italy. The method provided an overall view of the ecological network of the area, highlighting how linear infrastructures can affect animal populations and consequently, their survival probability.     

Site-directed mutagenesis of two aromatic residues lining the active site pocket of the yeast Ltp1

We mutated Trp(134) and Tyr(135) of the yeast LMW-PTP to explore their catalytic roles, demonstrating that the mutations of Trp(134) to Tyr or Ala, and Tyr(135) to Ala, all interfere with the formation of the phosphorylenzyme intermediate, a phenomenon that can be seen by the decrease in the kinetic constant of the chemical step (k(3)). Furthermore, we noted that the Trp(134) to Ala mutation causes a dramatic drop in k(cat)/K(m) and a slight enhancement of the dissociation constant K(s). The conservative mutant W134Y shows a k(cat)/K(m) very close to that of wild type, probably compensating the two-fold decrease of k(3) with an increase in substrate affinity. The Y135A mutation enhances the substrate affinity, but reduces the enzyme phosphorylation rate. The replacement of Trp(134) with alanine interferes with the partition between phosphorylenzyme hydrolysis and phosphotransfer from the phosphorylenzyme to glycerol and abolish the enzyme activation by adenine. Finally, we found that mutation of Trp(134) to Ala causes a dramatic change in the pH-rate profile that becomes similar to that of the D132A mutant, suggesting that an aromatic residue in position 134 is necessary to assist the proper positioning of the proton donor in the transition state of the chemical step.     

Glyoxalase 1 sustains the metastatic phenotype of prostate cancer cells via EMT control

Metastasis is the primary cause of death in prostate cancer (PCa) patients. Effective therapeutic intervention in metastatic PCa is undermined by our poor understanding of its molecular aetiology. Defining the mechanisms underlying PCa metastasis may lead to insights into how to decrease morbidity and mortality in this disease. Glyoxalase 1 (Glo1) is the detoxification enzyme of methylglyoxal (MG), a potent precursor of advanced glycation end products (AGEs). Hydroimidazolone (MG‐H1) and argpyrimidine (AP) are AGEs originating from MG‐mediated post‐translational modification of proteins at arginine residues. AP is involved in the control of epithelial to mesenchymal transition (EMT), a crucial determinant of cancer metastasis and invasion, whose regulation mechanisms in malignant cells are still emerging. Here, we uncover a novel mechanism linking Glo1 to the maintenance of the metastatic phenotype of PCa cells by controlling EMT by engaging the tumour suppressor miR‐101, MG‐H1‐AP and TGF‐β1/Smad signalling. Moreover, circulating levels of Glo1, miR‐101, MG‐H1‐AP and TGF‐β1 in patients with metastatic compared with non‐metastatic PCa support our in vitro results, demonstrating their clinical relevance. We suggest that Glo1, together with miR‐101, might be potential therapeutic targets for metastatic PCa, possibly by metformin administration.