Phosphorylated Tau protein in the myenteric plexus of the ileum and colon of normothermic rats and during synthetic torpor.

Tau protein is of primary importance for neuronal homeostasis and when hyperphosphorylated (PP-Tau), it tends to aggregate in neurofibrillary tangles, as is the case with tauopathies, a class of neurodegenerative disorders. Reversible PP-Tau accumulation occurs in the brain of hibernating rodents and it was recently observed in rats (a non-hibernator) during synthetic torpor (ST), a pharmacological-induced torpor-like condition. To date, the expression of PP-Tau in the rat enteric nervous system (ENS) is still unknown. The present study immunohistochemically investigates the PP-Tau expression in the myenteric plexus of the ileum and colon of normothermic rats (CTRL) and during ST, focusing on the two major subclasses of enteric neurons, i.e., cholinergic and nitrergic.Results showed that both groups of rats expressed PP-Tau, with a significantly increased percentage of PP-Tau immunoreactive (IR) neurons in ST vs. CTRL. In all rats, the majority of PP-Tau-IR neurons were cholinergic. In ST rats, the percentage of PP-Tau-IR neurons expressing a nitrergic phenotype increased, although with no significant differences between groups. In addition, the ileum of ST rats showed a significant decrease in the percentage of nitrergic neurons. In conclusion, our findings suggest an adaptive response of ENS to very low core body temperatures, with changes involving PP-tau expression in enteric neurons, especially the ileal nitrergic subpopulation. In addition, the high presence of PP-Tau in cholinergic neurons, specifically, is very interesting and deserves further investigation. Altogether, these data strengthen the hypothesis of a common cellular mechanism triggered by ST, natural hibernation and tauopathies occurring in ENS neurons.

Polymorphisms within the ARNT2 and CX3CR1 Genes Are Associated with the Risk of Developing Invasive Aspergillosis.

Invasive aspergillosis (IA) is a life-threatening infection that affects an increasing number of patients undergoing chemotherapy or allo-transplantation, and recent studies have shown that genetic factors contribute to disease susceptibility. In this two-stage, population-based, case-control study, we evaluated whether 7 potentially functional single nucleotide polymorphisms (SNPs) within the ARNT2 and CX3CR1 genes influence the risk of IA in high-risk hematological patients. We genotyped selected SNPs in a cohort of 500 hematological patients (103 of those had been diagnosed with proven or probable IA), and we evaluated their association with the risk of developing IA. The association of the most interesting markers of IA risk was then validated in a replication population, including 474 subjects (94 IA and 380 non-IA patients). Functional experiments were also performed to confirm the biological relevance of the most interesting markers. The meta-analysis of both populations showed that carriers of the ARNT2rs1374213G, CX3CR1rs7631529A, and CX3CR1rs9823718G alleles (where the RefSeq identifier appears as a subscript) had a significantly increased risk of developing IA according to a log-additive model (P value from the meta-analysis [PMeta] = 9.8 · 10-5, PMeta = 1.5 · 10-4, and PMeta =7.9 · 10-5, respectively). Haplotype analysis also confirmed the association of the CX3CR1 haplotype with AG CGG with an increased risk of IA (P = 4.0 · 10-4). Mechanistically, we observed that monocyte-derived macrophages (MDM) from subjects carrying the ARNTR2rs1374213G allele or the GG genotype showed a significantly impaired fungicidal activity but that MDM from carriers of the ARNT2rs1374213G and CX3CR1rs9823718G or CX3CR1rs7631529A alleles had deregulated immune responses to Aspergillus conidia. These results, together with those from expression quantitative trait locus (eQTL) data browsers showing a strong correlation of the CX3CR1rs9823718G allele with lower levels of CX3CR1 mRNA in whole peripheral blood (P = 2.46 · 10-7) and primary monocytes (P = 4.31 · 10-7), highlight the role of the ARNT2 and CX3CR1 loci in modulating and predicting IA risk and provide new insights into the host immune mechanisms involved in IA development.

Successful Treatment of Kaposi Sarcoma-Associated Herpesvirus Inflammatory Cytokine Syndrome After Kidney-Liver Transplant: Correlations With the Human Herpesvirus 8 miRNome and Specific T Cell Response.

After transplant, patient infection with human herpesvirus 8 (HHV-8) and Kaposi sarcoma-associated herpesvirus (KSHV) is known to cause aggressive tumors and severe nonneoplastic complications. These latter syndromes are driven by HHV-8/KSHV lytic reactivations and related hyperinflammatory host responses typically characterized by high viral loads, elevated levels of cytokines and other inflammation biomarkers, cytopenia, organ failure, high fever, and worsening conditions (with no evidence of B cell neoplasias). These disorders are associated with a high mortality rate, often due to lack of prompt diagnosis, effective therapeutic approaches, and adequate follow-up. These features resemble most of those defining the so-called KSHV-associated inflammatory cytokine syndrome (KICS), which was recently recognized in patients positive for human immunodeficiency virus (HIV). In this report, we describe-for the first time-a case of a KICS-like nonneoplastic recurrent complication occurring after transplant in an HIV-negative patient that was successfully treated by a combination of anti-CD20 monoclonal therapy, antivirals, and modification of the immunosuppressive regimen. In addition to clinical and laboratory findings collected during 3-year follow-up, we report novel experimental data on HHV-8-specific T cell dynamics and circulating microRNA profile, showing correlations with clinical course and other laboratory markers (including viral load, C-reactive protein, and cytokine levels), providing useful information about abnormal cellular and cytokine dynamics underlying HHV-8-associated inflammatory disorders in posttransplant patients.

Evaluation of serum (1 → 3)-ß-D-glucan clinical performance: kinetic assessment, comparison with galactomannan and evaluation of confounding factors.

PURPOSE: We investigated the clinical performance of (1 → 3)-ß-D-glucan (BG), as an early marker of invasive fungal infections (IFI), in different clinical settings. METHODS: BG serum levels were assessed by Fungitell (Associates of Cape Cod, Inc), in parallel with galactomannan (GM) when requested by clinicians. By a prospective monocentric study, 270 episodes at risk or with suspect of IFI were enrolled, namely 58 proven-probable invasive aspergillosis (IA), 27 proven invasive candidiasis (IC), 11 possible IC, 16 P.jirovecii pneumonia (PJP), 4 episodes of other IFI and 154 non-IFI controls. RESULTS: We found that (a) the BG overall sensitivity, specificity, positive predictive value and negative predictive value (NPV) were 87.9, 80.5, 76.7 and 89.9 %, respectively; (b) the highest sensitivity was found in the IC groups, followed by PJP, IA and other IFI groups; (c) an association was observed between BG kinetics and patients outcome; (d) in the IA episodes, the combination of BG or GM vs GM alone increased sensitivity from 60.0 to 83.3 % in the haematological patients; (e) false-positive BG results were related to Gram-negative infections or infusion of polyclonal IgM-enriched immunoglobulins, where high levels of BG were indeed detected. CONCLUSION: Besides strengthening its overall good clinical performance, we provide evidence that serum BG correlates with clinical outcome and that, once used in combination with GM, BG allows to enhance IFI diagnosis rate. The high sensitivity and NPV, observed in the Intensive Care Unit setting, open to BG validation as a marker for assessment of antifungal treatment.

Polymorphisms in Host Immunity-Modulating Genes and Risk of Invasive Aspergillosis: Results from the AspBIOmics Consortium.

Recent studies suggest that immune-modulating single-nucleotide polymorphisms (SNPs) influence the risk of developing cancer-related infections. Here, we evaluated whether 36 SNPs within 14 immune-related genes are associated with the risk of invasive aspergillosis (IA) and whether genotyping of these variants might improve disease risk prediction. We conducted a case-control association study of 781 immunocompromised patients, 149 of whom were diagnosed with IA. Association analysis showed that the IL4Rrs2107356 and IL8rs2227307 SNPs (using dbSNP numbering) were associated with an increased risk of IA (IL4Rrs2107356 odds ratio [OR], 1.92; 95% confidence interval [CI], 1.20 to 3.09; IL8rs2227307 OR, 1.73; 95% CI, 1.06 to 2.81), whereas the IL12Brs3212227 and IFNγrs2069705 variants were significantly associated with a decreased risk of developing the infection (IL12Brs3212227 OR, 0.60; 95% CI, 0.38 to 0.96; IFNγrs2069705 OR, 0.63; 95% CI, 0.41 to 0.97). An allogeneic hematopoietic stem cell transplantation (allo-HSCT)-stratified analysis revealed that the effect observed for the IL4Rrs2107356 and IFNγrs2069705 SNPs was stronger in allo-HSCT (IL4Rrs2107356 OR, 5.63; 95% CI, 1.20 to 3.09; IFNγrs2069705 OR, 0.24; 95% CI, 0.10 to 0.59) than in non-HSCT patients, suggesting that the presence of these SNPs renders patients more vulnerable to infection, especially under severe and prolonged immunosuppressive conditions. Importantly, in vitro studies revealed that carriers of the IFNγrs2069705C allele showed a significantly increased macrophage-mediated neutralization of fungal conidia (P = 0.0003) and, under stimulation conditions, produced higher levels of gamma interferon (IFNγ) mRNA (P = 0.049) and IFNγ and tumor necrosis factor alpha (TNF-α) cytokines (P value for 96 h of treatment with lipopolysaccharide [PLPS-96 h], 0.057; P value for 96 h of treatment with phytohemagglutinin [PPHA-96 h], 0.036; PLPS+PHA-96 h = 0.030; PPHA-72 h = 0.045; PLPS+PHA-72 h = 0.018; PLPS-96 h = 0.058; PLPS+PHA-96 h = 0.0058). Finally, we also observed that the addition of SNPs significantly associated with IA to a model including clinical variables led to a substantial improvement in the discriminatory ability to predict disease (area under the concentration-time curve [AUC] of 0.659 versus AUC of 0.564; P-2 log likehood ratio test = 5.2 · 10(-4) and P50.000 permutation test = 9.34 · 10(-5)). These findings suggest that the IFNγrs2069705 SNP influences the risk of IA and that predictive models built with IFNγ, IL8, IL12p70, and VEGFA variants can used to predict disease risk and to implement risk-adapted prophylaxis or diagnostic strategies.

Sleep and bodily functions: the physiological interplay between body homeostasis and sleep homeostasis.

Body homeostasis and sleep homeostasis may both rely on the complex integrative activity carried out by the hypothalamus. Thus, the three main wake-sleep (WS) states (i.e. wakefulness, NREM sleep, and REM sleep) may be better understood if the different cardio-respiratory and metabolic parameters, which are under the integrated control of the autonomic and the endocrine systems, are studied during sleep monitoring. According to this view, many physiological events can be considered as an expression of the activity that physiological regulations should perform in order to cope with the need to fulfill body and sleep homeostasis. This review is aimed at making an assessment of data showing the existence of a physiological interplay between body homeostasis and sleep homeostasis, starting from the spontaneous changes observed in the somatic and autonomic activity during sleep, through evidence showing the deep changes occurring in the central integration of bodily functions during the different WS states, to the changes in the WS states observed when body homeostasis is challenged by the external environment and when the return to normal ambient conditions allows sleep homeo- stasis to run without apparent physiological restrictions. The data summarized in this review suggest that an approach to the dichotomy between NREM and REM sleep based on physiological regulations may offer a framework within which observations that a traditional behavioral approach may overlook can be interpreted. The study of the interplay between body and sleep homeostasis appears, therefore, to be a way to understand the function of complex organisms beyond that of the specific regulations.

Trends in immune cell function assay and donor-specific HLA antibodies in kidney transplantation: A 3-year prospective study.

The immune cell function assay (ICFA) and de novo anti-donor-specific HLA antibodies (DSA) have been proposed as assays for immune monitoring in renal transplantation, but longitudinal studies examining the modification of both parameters over time and their relation with clinical events are lacking. We prospectively measured longitudinal changes in ICFA and DSA levels in 55 kidney transplant recipients over 3-year follow-up (534 visits) and analyzed their relation with the risk of developing acute rejections or infections. Seven patients (12.7%) developed biopsy-proven acute rejection, and 20 (36.4%) developed viral infections. At 3 years posttransplant, 28% of the patients had developed de novo DSA. ICFA levels peaked at 1-2 months posttransplant (p = 0.005) and leveled off thereafter. They were not associated with the risk of acute rejections, viral infections or development of de novo DSA. Instead, the incidence of de novo DSA was higher in patients who previously had viral infections (adjusted-odds ratio of de novo DSA associated with prior infections: 6.03 [95% CI, 1.64-22.06; p = 0.007]). Our prospective, longitudinal study does not support using ICFA to quantify the immune risk in kidney transplantation. Further studies are needed to confirm the relationship between viral infections and the subsequent development of de novo DSA.

Impact of early access to a palliative/supportive care intervention on pain management in patients with cancer.

BACKGROUND: No study has so far addressed whether differences do exist in the management of cancer pain between patients receiving usual care by primary specialists and those receiving early palliative/supportive intervention. PATIENTS AND METHODS: A multicentre cross-sectional study in 32 Italian Hospitals has included 1450 patients, receiving analgesic therapy for cancer pain: 602 with access to primary specialist alone (standard care, SC) and 848 with early access to a palliative/supportive care (ePSC) team, concomitant with primary oncology care. RESULTS: Statistically significant differences in the analgesic drug administration according to care model have been evident: non-opioids were more frequently used in SC (9.5% versus 2%; P<0.001), while strong opioids in ePSC group (80% versus 63%; P<0.001). The number of patients with severe pain was lower in ePSC compared with SC group (31% versus 17%; P<0.001). Results of multivariate analysis have shown that ePSC integrated with primary oncologic care (relative risk 0.69; 95% confidence interval 0.48-0.99; P=0.045) was an independent factor associated with a 31% reduced risk of suffering from severe pain. CONCLUSIONS: An ePSC team provides the most effective standard of analgesic therapy for cancer pain. A randomized clinical trial is needed to confirm these findings.

The effect of tracheostomy on swallowing function in open partial horizontal laryngectomies: preliminary experience.

OBJECTIVE: Tracheostomy is required to ensure a safe airway in open partial horizontal laryngectomies. The presence of the tracheostomy tube can contribute to post-operative dysphagia. This study aimed to evaluate the effects of a circumferential tracheostomy technique on swallowing. METHODS: A retrospective study was conducted of patients who underwent open partial horizontal laryngectomies between April 2018 and June 2019. Patients were divided into two groups based on the tracheostomy technique: group 1 had two stitches from the inferior tracheal ring to the skin; group 2 had circumferential fixation of the trachea to the skin. Demographic information, surgical data, post-operative rehabilitation course and complication details were collected and analysed. RESULTS: Twenty-four patients were enrolled. Patients in group 2 had significant improvement in the initial phases of swallowing rehabilitation. CONCLUSION: Tracheostomy with anchorage of the trachea to the skin by circumferential stitches could allow early removal of the tracheal tube, with a better swallowing outcome.

Diffractive and reactive scattering of H2 from Ru(0001): experimental and theoretical study.

We present a combined experimental and theoretical study of the diffraction of H(2) from Ru(0001) in the incident energy range 78-150 meV, and a theoretical study of dissociative chemisorption of H(2) in the same system. Pronounced out-of-plane diffraction was observed in the whole energy range studied. The energy dependence of the elastic diffraction intensities was measured along the two main symmetry directions for a fixed parallel translational energy. The data were compared with quantum dynamics calculations performed by using DFT-based, six-dimensional potential energy surfaces calculated with both the PW91 and RPBE functionals, as well as with a functional obtained from a weighted average of both (the MIX functional, which was earlier shown to perform quite well for H(2) + Cu(111)). Our results show that the PW91 functional describes the H(2) diffraction intensities more accurately than the RPBE and the MIX functionals, although the absolute values of these intensities are overestimated in the calculations. For the reaction probabilities a preference for one or the other functional cannot be given over the entire energy range probed by the sticking experiments. The PW91 functional yields too high reaction probabilities over the entire investigated energy range, but is better than RPBE at low collision energies (<0.1 eV). The RPBE functional gives too low reaction probabilities at low energy and somewhat too high reaction probabilities at high energy, but agrees better with experiment than PW91 for energies >0.1 eV. The results suggest that, in order to get a better description of both H(2) diffraction and dissociative chemisorption for this system, a specific reaction parameter functional for H(2) + Ru(0001) is needed that is a weighted average of functionals other than PW91 and RPBE. We speculate that differences between the H(2) + Ru(0001) system (early and low reaction barrier) and H(2) + Cu(111) (late and high reaction barrier) may well lead to fundamentally different specific reaction parameter functionals, and that including a reasonable accurate description of the van der Waals interaction might be important for H(2) + Ru(0001) which has barriers localised far away from the surface. Based on our results we advocate new, systematic combined theoretical and experimental studies of H(2) interacting with transition metals in early and late barrier systems, with the aim of determining whether specific reaction parameter functionals for these systems might differ in a systematic way.

Impact of setting of care on pain management in patients with cancer: a multicentre cross-sectional study.

BACKGROUND: No study has so far addressed whether differences do exist in the management of cancer-related pain in patients admitted to oncology and non-oncology settings. PATIENTS AND METHODS: A multicentre cross-sectional study in 48 Italian hospitals has enrolled 819 patients receiving analgesic therapy for cancer-related pain. Demographics and clinical and analgesic therapy information have been prospectively collected by standardized forms. Adequacy of pain management has been evaluated by the Pain Management Index (PMI). RESULTS: Differences in the analgesic drug administration according to settings of care have been evident, non-opioids more frequently being administered in non-oncology units (19.6% versus 7.0%; P < 0.0001), while strong opioids are more frequently used in the oncology units (69.5% versus 51.9%; P < 0.0001). The number of patients receiving inadequate therapy (PMI < 0) has lowered in oncology compared with non-oncology units (11.3% versus 18.8%; P = 0.0024). Results of multiple logistic regression analysis have shown that the admission to non-oncology setting [odds ratio (OR) = 1.75, 95% confidence interval (CI) = 1.15-2.67; P = 0.0096] and the absence of metastatic disease (OR = 1.60, 95% CI = 1.04-2.44; P = 0.0317) were independent factors associated with an increased risk of receiving an inadequate analgesic therapy. CONCLUSION: Oncology wards provide the most adequate standard of analgesic therapy for cancer-related pain.

Host immune genetic variations influence the risk of developing acute myeloid leukaemia: results from the NuCLEAR consortium.

The purpose of this study was to conduct a two-stage case control association study including 654 acute myeloid leukaemia (AML) patients and 3477 controls ascertained through the NuCLEAR consortium to evaluate the effect of 27 immune-related single nucleotide polymorphisms (SNPs) on AML risk. In a pooled analysis of cohort studies, we found that carriers of the IL13rs1295686A/A genotype had an increased risk of AML (PCorr = 0.0144) whereas carriers of the VEGFArs25648T allele had a decreased risk of developing the disease (PCorr = 0.00086). In addition, we found an association of the IL8rs2227307 SNP with a decreased risk of developing AML that remained marginally significant after multiple testing (PCorr = 0.072). Functional experiments suggested that the effect of the IL13rs1295686 SNP on AML risk might be explained by its role in regulating IL1Ra secretion that modulates AML blast proliferation. Likewise, the protective effect of the IL8rs2227307 SNP might be mediated by TLR2-mediated immune responses that affect AML blast viability, proliferation and chemorresistance. Despite the potential interest of these results, additional functional studies are still warranted to unravel the mechanisms by which these variants modulate the risk of AML. These findings suggested that IL13, VEGFA and IL8 SNPs play a role in modulating AML risk.

Prevalence of human herpesvirus-6 chromosomal integration (CIHHV-6) in Italian solid organ and allogeneic stem cell transplant patients.

The unique phenomenon of human herpesvirus-6 (HHV-6) chromosomal integration (CIHHV-6) may account for clinical drawbacks in transplant setting, being misinterpreted as active infection and leading to unnecessary and potentially harmful treatments. We have investigated the prevalence of CIHHV-6 in 205 consecutive solid organ (SO) and allogeneic stem cell transplant (alloSCT) Italian patients. Fifty-two (38.5%) of 135 solid organ transplant (SOT) and 16 (22.8%) of 70 alloSCT patients resulted positive for plasma HHV-6 DNA by real-time polymerase chain reaction. Seven SOT and three alloSCT patients presented HHV-6-related diseases, requiring antivirals. Two further patients (0.9%) were identified, presenting high HHV-6 loads. The quantification of HHV-6 on hair follicles disclosed the integrated state, allowing the discontinuation of antivirals. Before starting specific treatments, CIHHV-6 should be excluded in transplant patients with HHV-6 viremia by the comparison of HHV-6 loads on different fluids and tissues. Pretransplantation screening of donors and recipients may further prevent the misdiagnosis of CIHHV-6.

An outbreak of sarcocystosis in psittacines and a pigeon in a zoological collection in Brazil.

This report describes an outbreak of acute pulmonary sarcocystosis in different species of captive psittacines and in a Luzon bleeding-heart pigeon (Gallicolumba luzonica) in a zoological collection in Brazil. A majority of the birds were found dead and had exhibited no previous clinical signs. Grossly, pulmonary congestion and edema were the most-common findings. Enlarged and congested livers and spleens were also frequently observed. Microscopically, there was edema, fibrin exudation, congestion, and perivascular and interstitial lymphoplasmacytic infiltration associated with numerous sinuous schizonts of Sarcocystis sp. in the lungs. Mild to moderate myocarditis, hepatitis, splenitis, and interstitial nephritis were also observed in the birds. Immunohistochemistry confirmed Sarcocystis sp. in the capillaries of lungs, hearts, livers, and spleens of most of the birds, but also in the pancreas, kidney, intestine, proventriculus, and brain of a few birds. The probable source of Sarcocystis sp. in these birds was the wild opossum (Didelphis albiventris), a common inhabitant of a local forest that surrounds the Belo Horizonte Zoo (Fundação Zoo-Botânica). This is the first documentation of Sarcocystis infection in psittacines and a pigeon from Brazil.

Cytarabine-related lung infiltrates on high resolution computerized tomography: a possible complication with benign outcome in leukemic patients.

Potentially fatal lung toxicity occurs in 12-20% of leukemic patients treated with cytarabine especially at intermediate to high doses, usually presenting as noncardiogenic pulmonary edema (NCPE). Anecdotally the association between cytarabine and the onset of bronchiolitis obliterans organizing pneumonia (BOOP) has been reported. We describe here three cases of patients affected by acute myeloid leukemia (AML) treated with chemotherapeutic regimens including high dose cytarabine, who developed early onset of fever, mild dyspnea, moderate hypoxemia on arterial blood gas analysis and lung infiltrates documented by high-resolution computerized tomography (HRCT), with a more indolent behaviour and a benign clinical outcome, compared with similar cases previously reported in the literature. Our cases widen the spectrum of clinical features of cytarabine-related toxicity in leukemic patients.

Anticancer drug-loaded quantum dots engineered polymeric nanoparticles: Diagnosis/therapy combined approach.

Primary Effusion Lymphoma (PEL) is an HHV-8-related non Hodgkin lymphoma localized in body cavities (as pleural, peritoneal and pericardial) presenting lymphomatous effusion that, until now, lack of an effective therapy. Curcumin was reported to display pro-apoptotic effect via the inhibition of the JAK/STAT pathway, that is overexpressed in PEL cells, as consequence of virus infection. The administration of curcumin is severely restricted by its physicochemical properties, mainly its low solubility in biological fluid and consequently low bioavailability. Encapsulation into biocompatible and biodegradable PLGA nanoparticles (NPs) could be a strategy to overcome biological limits of curcumin, offering a valuable step forward for its clinical application. In this study we described single-emulsion process for curcumin loading into NPs (encapsulation efficiency about 35%). We applied a post-formulation strategy (NHS/EDC reaction) to decorate the surface of the curcumin-loaded NPs with quantum dots (QDs) as imaging agents (QDs-NPs-Cur, 24pmol of QDs per 100mg of NPs) obtaining tools useful for possible application in theranostic approach. Bifunctionalized NPs were tested in vitro on two PEL's cell line (BCBL-1 and HBL-6). The efficacy of the treatment was evaluated by cytofluorimetric assay by measuring both cell viability and cell density. We found that the NPs significantly improve the cellular effect of curcumin (respect to free drug). Moreover, by means of confocal microscopy, both the localization of bifunctional NPs and of the released drug were easily detectable. Thus, we conclude that the delivery of curcumin using bifunctional traceable NPs is a promising future approach for the diagnosis and the treatment of PEL.

Predicting catalysis: understanding ammonia synthesis from first-principles calculations.

Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state theory with or without tunneling corrections, and quantum dynamics) to a range of relevant elementary reaction steps, such as N(2) dissociation, H(2) dissociation, and hydrogenation of the intermediate reactants. A complete kinetic model based on the most relevant elementary steps can be established for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations. Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully integrated tool in the search for the next generation of catalysts.

[Imipenem-cilastatin use in a university hospital in Chile]. / Cumplimiento sobre las recomendaciones de uso y evaluación del impacto económico de un programa de uso restringido de imipenem-cilastatina.

Imipenem is an expensive broad-spectrum antimicrobial, reserved for infections caused by multi-resistant nosocomial pathogens. Since 2001 our university hospital applies a restriction policy that allows rejecting or authorizing its use after a supervising evaluation with pre-specified criteria for appropriate or inappropriate use. An audit was performed for all the supervisions made during the periods of March-April and September-October, 2004, totalling 136 treatments. In global terms, 58.1% of treatments were considered appropriate and 11.8% inappropriate; other 20.6% had been discontinued by physicians in charge prior to evaluation. Susceptibility to other antimicrobials compounds was the main reason for inappropriate use. The remaining fraction involved deceased or discharged patients. Discontinuation of treatments by supervising physicians allowed to save 75 days and 362 vials of imipenem equivalent to US $ 6,777 during this period after discounting administrative and human resources costs.

The human A-myb protein is a strong activator of transcription.

The A-myb gene belongs to the family of the c-myb proto-oncogene. We report here the cloning from a B lymphocyte cDNA library of the previously missing 3' half of the human A-myb cDNA, thus closing the previously still incomplete open reading frame. Analysis of the homologies between the different myb proteins reveals four domains of high conservation. We show, using a polyclonal rabbit antibody, that the 90 kd human A-myb protein is nuclear and that it activates transcription from the KHK-CAT reporter 6-10 times more strongly than c-myb in NIH3T3 cells. The transactivating function of A-myb depends on the presence of the myb binding site in the reporter, and on both the DNA binding and acidic domains of the A-myb protein. The bacterially expressed protein protects the myb binding sites of the reporter in footprint experiments. Binding of the A-myb protein is shown in gel retardation assays to be specific for the classical c-myb recognition sequence PyAACG/TG. In addition, like c-myb, A-myb binds more strongly to the MIM-A synthetic oligonucleotide that carries the TAACGG sequence than to the MBS-I oligonucleotide containing TAAGTG. Finally, DNA binding activity is demonstrated to require the N-terminal portion of the protein containing the three tandem repeats of amino acids conserved in all myb proteins. We have thus shown that the A-myb protein is a strong activator of transcription and that this activity depends on both the DNA-binding and acidic domains.