Systematics and life cycles of four avian schistosomatids from Southern Cone of South America.

Relative to the numerous studies focused on mammalian schistosomes, fewer include avian schistosomatids particularly in the southern hemisphere. This is changing and current research emerging from the Neotropics shows a remarkable diversity of endemic taxa. To contribute to this effort, nine ducks (Spatula cyanoptera, S.versicolor, Netta peposaca), 12 swans (Cygnus melancoryphus) and 1,400 Physa spp. snails from Chile and Argentina were collected for adults and larval schistosomatids, respectively. Isolated schistosomatids were preserved for morphological and molecular analyses (28S and COI genes). Four different schistosomatid taxa were retrieved from birds: Trichobilharzia sp. in N. peposaca and S. cyanoptera that formed a clade; S.cyanoptera and S. versicolor hosted Trichobilharzia querquedulae; Cygnus melancoryphus hosted the nasal schistosomatid, Nasusbilharzia melancorhypha; and one visceral, Schistosomatidae gen. sp., which formed a clade with furcocercariae from Argentina and Chile from previous work. Of the physid snails, only one from Argentina had schistosomatid furcocercariae that based on molecular analyses grouped with T. querquedulae. This study represents the first description of adult schistosomatids from Chile as well as the elucidation of the life cycles of N.melancorhypha and T. querquedulae in Chile and Neotropics, respectively. Without well-preserved adults, the putative new genus Schistosomatidae gen. sp. could not be described, but its life cycle involves Chilina spp. and C. melancoryphus. Scanning electron microscopy of T. querquedulae revealed additional, undescribed morphological traits, highlighting its diagnostic importance. Authors stress the need for additional surveys of avian schistosomatids from the Neotropics to better understand their evolutionary history.

Superconductivity Emerging from an Electronic Phase Separation in the Charge Ordered Phase of RbFe_{2}As_{2}.

^{75}As, ^{87}Rb, and ^{85}Rb nuclear quadrupole resonance (NQR) and ^{87}Rb nuclear magnetic resonance measurements in a RbFe_{2}As_{2} iron-based superconductor are presented. We observe a marked broadening of the ^{75}As NQR spectrum below T_{0}≃140 K which is associated with the onset of a charge order in the FeAs planes. Below T_{0} we observe a power-law decrease in the ^{75}As nuclear spin-lattice relaxation rate down to T^{*}≃20 K. Below T^{*} the nuclei start to probe different dynamics owing to the different local electronic configurations induced by the charge order. A fraction of the nuclei probes spin dynamics associated with electrons approaching a localization while another fraction probes activated dynamics possibly associated with a pseudogap. These different trends are discussed in light of an orbital selective behavior expected for the electronic correlations.

Suppression of the p53- or pRB-mediated G1 checkpoint is required for E2F-induced S-phase entry.

Deregulation of the retinoblastoma protein (pRB) pathway is a hallmark of cancer. In the absence of other genetic alterations, this deregulation results in lack of differentiation, hyperproliferation and apoptosis. The pRB protein acts as a transcriptional repressor by targeting the E2F transcription factors, whose functions are required for entry into S phase. Increased E2F activity can induce S phase in quiescent cells--this is a central element of most models for the development of cancer. We show that although E2F1 alone is not sufficient to induce S phase in diploid mouse and human fibroblasts, increased E2F1 activity can result in S-phase entry in diploid fibroblasts in which the p53-mediated G1 checkpoint is suppressed. In addition, we show that E2F1 can induce S phase in primary mouse fibroblasts lacking pRB. These results indicate that, in addition to acting as an E2F-dependent transcriptional repressor, pRB is also required for the cells to retain the G1 checkpoint in response to unprogrammed proliferative signals.

Apaf-1 is a transcriptional target for E2F and p53.

Loss of function of the retinoblastoma protein, pRB, leads to lack of differentiation, hyperproliferation and apoptosis. Inactivation of pRB results in deregulated E2F activity, which in turn induces entry to S-phase and apoptosis. Induction of apoptosis by either the loss of pRB or the deregulation of E2F activity occurs via both p53-dependent and p53-independent mechanisms. The mechanism by which E2F induces apoptosis is still unclear. Here we show that E2F1 directly regulates the expression of Apaf-1, the gene for apoptosis protease-activating factor 1. These results provide a direct link between the deregulation of the pRB pathway and apoptosis. Furthermore, because the pRB pathway is functionally inactivated in most cancers, the identification of Apaf-1 as a transcriptional target for E2F might explain the increased sensitivity of tumour cells to chemotherapy. We also show that, independently of the pRB pathway, Apaf-1 is a direct transcriptional target of p53, suggesting that p53 might sensitize cells to apoptosis by increasing Apaf-1 levels.

Genotypic diversity of Salmonella ser. Abortusequi isolates from Argentina.

BACKGROUND: Salmonella enterica subsp. enterica serovar Abortusequi (S. Abortusequi) is a serotype restricted to equines, which produces abortion outbreaks. Nowadays the disease is being reported in different countries including Argentina thus generating an important impact in the equine industry. Molecular characterization of the 95 kb virulence plasmid and the spvC gene of S. Abortusequi demonstrated their importance in the pathogenicity of the serotype. In the last decades, high clonality of S. Abortusequi was identified in Japan, Mongolia and Croatia. OBJECTIVES: The aim of this work was to characterize S. Abortusequi isolates obtained in Argentina between 2011 and 2016 by virulence-gene profiling and pulsed-field gel electrophoresis. STUDY DESIGN: Case report. METHODS: S. Abortusequi isolates were studied by virulence-gene profiling and pulsed-field gel electrophoresis. RESULTS: Four virulence profiles and nine pulsed-field gel electrophoresis pulsotypes were identified among the 27 isolates included in the study. Different strains were found in the same outbreak and/or farm suggesting the presence of different sources of infection or mutation of isolates. MAIN LIMITATIONS: The number of related and nonrelated strains. More isolates may be necessary for a more intensive study. CONCLUSIONS: Most strains presented the same virulence profile, being positive for all the studied genes except gipA and sopE1, which are involved in intestinal virulence. Only few isolates showed different results in the same outbreak or farm. Unlike other studies, our results demonstrate a considerable diversity of S. Abortusequi pulsed-field gel electrophoresis pulsotypes, which suggests that different sources of infection may be involved within the same outbreak.

Fast recovery of the pristine magnetic and structural phases in superconducting LaFeAsO0.89F0.11 by Mn/Fe substitution.

We report an experimental study on the effect of Mn impurities in the optimally doped [Formula: see text] compound. The results show that a very tiny amount of Mn, of the order of 0.1%, is enough to destroy superconductivity and to recover at low temperatures both the magnetic ground state and the orthorhombic structure of the pristine LaFeAsO parent compound. The results are discussed within a model where electron correlations enhance the Ruderman-Kittel-Kasuya-Yosida interaction among impurities.

The role of p53 and pRB in apoptosis and cancer.

Loss of function of both the p53 pathway and the retinoblastoma protein (pRB) pathway plays a significant role in the development of most human cancers. Loss of pRB results in deregulated cell proliferation and apoptosis, whereas loss of p53 desensitizes cells to checkpoint signals, including apoptosis. In the past two years, mouse genetics and gene expression profiling have led to major advances in our understanding of how the pRB and p53 pathways regulate apoptosis and thus the development of tumours.

Lymphangioma communicating with the excretory system.

Lymphangioma is a rare benign tumor caused by failure in the development of the lymphatic communicating system. The corresponding nomenclature is confusing. In recent years ''renal lymphangiectasia'' is the preferred name. Although this disease may occur in any site of the body, the neck (75%) and axillary area (20%) are the most common sites, and the kidney is occasionally involved. We report a case of lymphangioma communicating with the urinary system in a 61-year-old man diagnosed by CT scan treated with nephrectomy and histological confirmation.

Inhibition of Burkitt's lymphoma cells growth in SCID mice by a PNA specific for a regulatory sequence of the translocated c-myc.

In Burkitt's lymphoma (BL) cells due to a t(8;14) chromosomal translocation c-myc is often placed in proximity to the Emu enhancer of the Ig locus and upregulated. We demonstrated that in BL cells a peptide nucleic acid (PNA), complementary to intronic Emu sequences (PNAEmuwt), specifically blocks the expression of the c-myc oncogene under the Emu enhancer control and inhibits BL cell growth in culture. Here, we investigated whether PNAEmuwt was also able to block tumor growth in SCID mice inoculated with human BL cell lines. After subcutaneous inoculum in mice BL cells reproducibly form tumors. Both pre-treatment of BL cells with PNAEmuwt before inoculum and chronic intravenous administration of PNAEmuwt to mice already inoculated with BL cells selectively caused increased latency of tumor appearance and decreased final tumor size. Tumors from PNAEmuwt-treated animals showed substantial areas of cell necrosis and of c-myc downregulation. Inhibition of tumor growth was specific and was not observed with PNAEmumut carrying sequence mutations and in BL cell lines where the translocated c-myc is not under the control of the Emu enhancer. These data confirm the potential therapeutic value of PNA targeted to regulatory non-coding regions.

Induction of S-phase entry by E2F transcription factors depends on their nuclear localization.

The E2F transcription factors are essential for regulating the correct timing of activation of several genes whose products are implicated in cell proliferation and DNA replication. The E2Fs are targets for negative regulation by the retinoblastoma protein family, which includes pRB, p107, and p130, and they are in a pathway that is frequently found altered in human cancers. There are five members of the E2F family, and they can be divided into two functional subgroups. Whereas, upon overexpression, E2F-1, -2, and -3 induce S phase in quiescent fibroblasts and override G1 arrests mediated by the p16INK4A tumor suppressor protein or neutralizing antibodies to cyclin D1, E2F-4 and -5 do not. Using E2F-1 and E2F-4 as representatives of the two subgroups, we showed here, by constructing a set of chimeric proteins, that the amino terminus of E2F-1 is sufficient to confer S-phase-inducing potential as well as the ability to efficiently transactivate an E2F-responsive promoter to E2F-4. We found that the E2F-1 amino terminus directs chimeric proteins to the nucleus. Surprisingly, a short nuclear localization signal derived from simian virus 40 large T antigen could perfectly substitute for the presence of the E2F-1 amino terminus in these assays. Thus, nuclearly localized E2F-4, when overexpressed, displayed biological activities similar to those of E2F-1. Furthermore, we showed that nuclear localization of endogenous E2F-4 is cell cycle regulated, with E2F-4 being nuclear in the G0 and early G1 phases and mainly cytoplasmic after the pRB family members have become phosphorylated. We propose a novel mechanism for the regulation of E2F-dependent transcription in which E2F-4 regulates transcription only from G0 until mid- to late G1 phase whereas E2F-1 is active in late G1 and S phases, until it is inactivated by cyclin A-dependent kinase in late S phase.

CDC25A phosphatase is a target of E2F and is required for efficient E2F-induced S phase.

Functional inactivation of the pRB pathway is a very frequent event in human cancer, resulting in deregulated activity of the E2F transcription factors. To understand the functional role of the E2Fs in cell proliferation, we have developed cell lines expressing E2F-1, E2F-2, and E2F-3 fused to the estrogen receptor ligand binding domain (ER). In this study, we demonstrated that activation of all three E2Fs could relieve the mitogen requirement for entry into S phase in Rat1 fibroblasts and that E2F activity leads to a shortening of the G(0)-G(1) phase of the cell cycle by 6 to 7 h. In contrast to the current assumption that E2F-1 is the only E2F capable of inducing apoptosis, we showed that deregulated E2F-2 and E2F-3 activities also result in apoptosis. Using the ERE2F-expressing cell lines, we demonstrated that several genes containing E2F DNA binding sites are efficiently induced by the E2Fs in the absence of protein synthesis. Furthermore, CDC25A is defined as a novel E2F target whose expression can be directly regulated by E2F-1. Data showing that CDC25A is an essential target for E2F-1, since its activity is required for efficient induction of S phase by E2F-1, are provided. Finally, our results show that expression of two E2F target genes, namely CDC25A and cyclin E, is sufficient to induce entry into S phase in quiescent fibroblasts. Taken together, our results provide an important step in defining how E2F activity leads to deregulated proliferation.

Fast wide-volume functional imaging of engineered in vitro brain tissues.

The need for in vitro models that mimic the human brain to replace animal testing and allow high-throughput screening has driven scientists to develop new tools that reproduce tissue-like features on a chip. Three-dimensional (3D) in vitro cultures are emerging as an unmatched platform that preserves the complexity of cell-to-cell connections within a tissue, improves cell survival, and boosts neuronal differentiation. In this context, new and flexible imaging approaches are required to monitor the functional states of 3D networks. Herein, we propose an experimental model based on 3D neuronal networks in an alginate hydrogel, a tunable wide-volume imaging approach, and an efficient denoising algorithm to resolve, down to single cell resolution, the 3D activity of hundreds of neurons expressing the calcium sensor GCaMP6s. Furthermore, we implemented a 3D co-culture system mimicking the contiguous interfaces of distinct brain tissues such as the cortical-hippocampal interface. The analysis of the network activity of single and layered neuronal co-cultures revealed cell-type-specific activities and an organization of neuronal subpopulations that changed in the two culture configurations. Overall, our experimental platform represents a simple, powerful and cost-effective platform for developing and monitoring living 3D layered brain tissue on chip structures with high resolution and high throughput.

Cetuximab for treatment of metastatic colorectal cancer.

In the past decade the median overall survival of patients with metastatic colorectal cancer has increased from 12 to more than 20 months, mostly due to the new chemotherapeutic agents, irinotecan and oxaliplatin. Most recently, targeted therapies, that inhibit specific cancer pathways and molecules, have shown promising results in the treatment of patients with metastatic colorectal cancer and other solid tumors. One of the most studied targets for anticancer therapy is the epidermal growth factor receptor (EGFR), which is overexpressed in a variety of malignancies. Cetuximab, an anti-EGFR chimeric monoclonal antibody, has shown clinically meaningful antitumor activity in patients with metastatic colorectal cancer in several clinical trials. Efforts of physicians and researchers are currently directed towards the identification of predictive factors (clinical or molecular) of clinical outcome, with the aim of both optimizing the therapeutic index and dealing with increasing costs of these new compounds.

Relationship between human mammaglobin mRNA expression in breast cancer tissue and clinico-pathologic features of the tumors.

Human mammaglobin (hMAM) has recently been recognized as a breast associated glycoprotein. Although the biological role of hMAM is unknown, it has been previously reported that hMAM gene expression is a marker of low biological and clinical aggressiveness of breast cancer (BC). In this study, 148 cases of BC tissues were investigated for hMAM mRNA expression by reverse transcriptase-polymerase chain reaction (RT-PCR). In order to evaluate its prognostic value, hMAM was correlated with age of patients, type and size of tumor, nodal stage, histologic grade, c-erbB-2 over expression, Ki67 labelling index, estrogen receptor (ER) status and progesterone receptor (PGR) status. Fisher's exact test was used to examine the association between different parameters and hMAM. hMAM was expressed in 138/148 (93%) of BC tissues examined. Among the 10 hMAM negative cases, 8 were invasive ductal carcinomas (microscopically higher G3 grade) and 2 infiltrating lobular carcinomas. We found a significant association (p = 0.020) between absence of hMAM mRNA and G3 histologic grade but not with any other prognostic parameters studied. The present study indicates that lack of hMAM expression is restricted to the BC with G3 grading. Further studies are needed to clarify the biological basis and the clinical significance of our results.

Simultaneous determination of 222Rn and 220Rn exhalation rates from building materials used in Central Italy with accumulation chambers and a continuous solid state alpha detector: influence of particle size, humidity and precursors concentration.

A method to determine simultaneously the rates of 222Rn and 220Rn released from building materials quarried in Central Italy is presented. The method makes use of a continuous monitor equipped with a solid state alpha detector, in-line connected to a small accumulation chamber. The effects of chamber leakage and back diffusion on 222Rn free exhalation rate is evaluated. The influence of available exhalation surface, humidity content and precursors concentration on radon and thoron exhalation rates is investigated.

[The risks of out of area missions: depleted uranium]. / I rischi delle missioni fuori area: l'uranio impoverito.

Depleted uranium (DU), a waste product of uranium enrichment, has several civilian and military applications. It was used as armor-piercing ammunition in international conflicts and was claimed to contribute to health problems, known as the Gulf War Syndrome and recently as the Balkan Syndrome. Leukaemia/Limphoma cases among UN soldiers in the Balkans have been related hypothetically to exposure to DU. The investigations published in the scientific literature give no support for this hypothesis. However future follow-up is necessary for evaluation of long-term risk.

Altered expression of heterogenous nuclear ribonucleoproteins and SR factors in human colon adenocarcinomas.

Alternative splicing is part of the expression program of a wide number of genes implicated in cell growth and differentiation. Although the occurrence of inappropriate alternative splicing in tumors has started to emerge, the underlying molecular mechanisms have been, thus far, largely unexplored. We have investigated the alternative splicing pattern of the CD44 gene in specimens of nonfamilial colon adenocarcinomas at different stages of tumor progression. In the same patients, we have assessed by Northern blotting analysis the mRNA levels of different heterogeneous nuclear ribonucleoproteins and SR factors, all involved in pre-mRNA splicing and, more in general, in mRNA maturation. The results of this analysis highlight a general rule for the mode of splicing of the CD44 pre-mRNA. Moreover, we found that the mRNA levels of different SR proteins in tumor specimens are different from, and usually lower than, those detected in samples of nonpathological tissue adjacent to the tumor. Quantitative analysis demonstrates that, in tumors, the mRNA levels of ASF, SRp40, SRp55, and SRp75, when normalized to those of heterogeneous nuclear ribonucleoprotein A1, are lower than those of SRp20 and SRp30. Interestingly, this reduction is more drastic in patients showing a more altered CD44 splicing pattern and seems to be related to the propensity to develop metastases.

In vitro dephosphorylation of alpha-crystallin is dependent on the state of oligomerization.

alphaA- and alphaB-crystallin, members of the small heat shock protein family, are present in lens cell extracts as large aggregates. Both alpha-crystallins are found partially phosphorylated. This study tests the ability of five phosphatases (protein phosphatase PP1, PP2A, PP2B, alkaline and acid phosphatases) to dephosphorylate alphaA- and alphaB-crystallin in vitro. Activity of a phosphatase was dependent on the size of the aggregate. Each of the phosphatases tested showed different specificity and efficiency towards alphaA- and alphaB-crystallins, which depended on the oligomeric state of the alpha-crystallin aggregate. Alkaline phosphatase dephosphorylated both alphaA- and alphaB-crystallin. The reaction was faster when alpha-crystallin was in a tetrameric form. PP2A dephosphorylated primarily alphaA-crystallin but only after the conversion of alpha-crystallin to tetramers. PP1 and PP2B did not dephosphorylate either alphaA- or alphaB-crystallins present as large aggregates but could not be tested on the lower molecular weight form of alphaA-crystallin. Acid phosphatase dephosphorylated both alphaA- and alphaB-crystallin. The results suggest that an important relationship exists between the structure of alpha-crystallin and its level of phosphorylation in the cell.

Purification and partial characterization of the soluble low Km 5'-nucleotidase from human seminal plasma.

Soluble low Km 5'-nucleotidase from human seminal plasma has been purified to homogeneity by one affinity and two gel-filtration chromatographic steps. The pure enzyme had a specific activity of 2000 nmol min-1 mg-1. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of purified low Km 5'-nucleotidase revealed a single polypeptide band of 40 +/- 7 kDa and a tetrameric structure of 160 +/- 10 kDa has been proposed for the native enzyme. The kinetic properties of low Km 5'-nucleotidase have been determined and rather unique characteristics have been found for this soluble low Km 5'-nucleotidase: the substrate efficiency was slightly higher for IMP with an optimum pH at 7.5; the enzyme showed an absolute dependence on Mg2+ ions. Ca2+ could replace Mg2+ ions for activity while other divalent cations could not substitute for Mg2+; the enzymes were equally activated by ATP and ADP up to 0.1 mM concentrations. At higher concentrations up to 1 mM, ADP was still an activator while ATP caused a gradual decrease of activation to the native activity. This effect could not be related to the Mg-ATP = complexes since the enzymic preparation Mg(2+)-free still showed the same biphasic pattern of activation.

Focal lymphocytic myocarditis in acquired immunodeficiency syndrome (AIDS): a correlative morphologic and clinical study in 26 consecutive fatal cases.

In 26 consecutive cases with acquired immunodeficiency syndrome (AIDS) the main cardiac findings were Kaposi's sarcoma in 2 cases, microfocal myocardial abscess in 1, subendocardial infarct necrosis in 2, contraction band necrosis in 13, lymphocytic myocarditis in 9, intramyocardial lymphocytic infiltrates without myocell necrosis in 7 and epicardial lymphocytic infiltrates in 4. No patient had congestive heart failure. However, two-dimensional echocardiography performed in eight patients demonstrated functional abnormalities in six (fractional shortening ranging from 18 to 30%, globular shape, hypokinesia, mild ventricular dilation). Four of these six patients had lymphocytic myocarditis and two had lymphocytic infiltrates in the myocardium and epicardium without myocell necrosis. No lymphocytic infiltrates were seen in the two cases with a normal echocardiogram. Quantitative analysis indicated that involvement of the heart by lymphocytic myocarditis is inadequate in itself to explain dysfunction. It remains to be established 1) whether lymphocytic myocarditis is a possible indication of a more widespread molecular disorder, and 2) what its eventual relation with dilated cardiomyopathy will be.