Tracing ΦX174 bacteriophage spreading during aerosol-generating procedures in a dental clinic

OBJECTIVE

The aim of this study was to test the plausibility of using the ΦX174 bacteriophage as a tracer of viral aerosols spreading in a dental aerosol-generating procedure (AGP) model.

METHODS

ΦX174 bacteriophage (~ 10⁸ plaque-forming units (PFU)/mL) was added into instrument irrigation reservoirs and aerosolized during class-IV cavity preparations followed by composite fillings on natural upper-anterior teeth (n = 3) in a phantom head. Droplets/aerosols were sampled through a passive approach that consisted of Escherichia coli strain C600 cultures immersed in a LB top agar layer in Petri dishes (PDs) in a double-layer technique. In addition, an active approach consisted of E coli C600 on PDs sets mounted in a six-stage cascade Andersen impactor (AI) (simulating human inhalation). The AI was located at 30 cm from the mannequin during AGP and afterwards at 1.5 m. After collection PDs were incubated overnight (18 h at 37 °C) and bacterial lysis was quantified.

RESULTS

The passive approach disclosed PFUs mainly concentrated over the dental practitioner, on the mannequin's chest and shoulder and up to 90 cm apart, facing the opposite side of the AGP's source (around the spittoon). The maximum aerosol spreading distance was 1.5 m in front of the mannequin's mouth. The active approach disclosed collection of PFUs corresponding to stages (and aerodynamic diameters) 5 (1.1-2.1 µm) and 6 (0.65-1.1 µm), mimicking access to the lower respiratory airways.

CONCLUSION

The ΦX174 bacteriophage can be used as a traceable viral surrogate in simulated studies contributing to understand dental bioaerosol's behavior, its spreading, and its potential threat for upper and lower respiratory tract.

CLINICAL RELEVANCE

The probability to find infectious virus during AGPs is high. This suggests the need to continue characterizing the spreading viral agents in different clinical settings through combination of passive and active approaches. In addition, subsequent identification and implementation of virus-related mitigation strategies is relevant to avoid occupational virus infections.

Pembrolizumab in combination with gemcitabine for patients with HER2-negative advanced breast cancer: GEICAM/2015-04 (PANGEA-Breast) study

BACKGROUND

We evaluated a new chemoimmunotherapy combination based on the anti-PD1 monoclonal antibody pembrolizumab and the pyrimidine antimetabolite gemcitabine in HER2- advanced breast cancer (ABC) patients previously treated in the advanced setting, in order to explore a potential synergism that could eventually obtain long term benefit in these patients.

METHODS

HER2-negative ABC patients received 21-day cycles of pembrolizumab 200 mg (day 1) and gemcitabine (days 1 and 8). A run-in-phase (6 + 6 design) was planned with two dose levels (DL) of gemcitabine (1,250 mg/m² [DL0]; 1,000 mg/m² [DL1]) to determine the recommended phase II dose (RP2D). The primary objective was objective response rate (ORR). Tumor infiltrating lymphocytes (TILs) density and PD-L1 expression in tumors and myeloid-derived suppressor cells (MDSCs) levels in peripheral blood were analyzed.

RESULTS

Fourteen patients were treated with DL0, resulting in RP2D. Thirty-six patients were evaluated during the first stage of Simon's design. Recruitment was stopped as statistical assumptions were not met. The median age was 52; 21 (58%) patients had triple-negative disease, 28 (78%) visceral involvement, and 27 (75%) ≥ 2 metastatic locations. Progression disease was observed in 29 patients. ORR was 15% (95% CI, 5-32). Eight patients were treated ≥ 6 months before progression. Fourteen patients reported grade ≥ 3 treatment-related adverse events. Due to the small sample size, we did not find any clear association between immune tumor biomarkers and treatment efficacy that could identify a subgroup with higher probability of response or better survival. However, patients that experienced a clinical benefit showed decreased MDSCs levels in peripheral blood along the treatment.

CONCLUSION

Pembrolizumab 200 mg and gemcitabine 1,250 mg/m² were considered as RP2D. The objective of ORR was not met; however, 22% patients were on treatment for ≥ 6 months. ABC patients that could benefit of chemoimmunotherapy strategies must be carefully selected by robust and validated biomarkers. In our heavily pretreated population, TILs, PD-L1 expression and MDSCs levels could not identify a subgroup of patients for whom the combination of gemcitabine and pembrolizumab would induce long term benefit.

TRIAL REGISTRATION

ClinicalTrials.gov and EudraCT (NCT03025880 and 2016-001,779-54, respectively). Registration dates: 20/01/2017 and 18/11/2016, respectively.

Olaparib in combination with pegylated liposomal doxorubicin for platinum-resistant ovarian cancer regardless of BRCA status: a GEICO phase II trial (ROLANDO study)

BACKGROUND

There is limited evidence for the benefit of olaparib in platinum-resistant ovarian cancer (PROC) patients with BRCA wild-type tumors. This study investigated whether this combination of a DNA-damaging chemotherapy plus olaparib is effective in PROC regardless BRCA status.

PATIENTS AND METHODS

Patients with high-grade serous or endometrioid ovarian carcinoma and one previous PROC recurrence were enrolled regardless of BRCA status. Patients with ≤4 previous lines (up to 5 in BRCA-mut) with at least one previous platinum-sensitive relapse were included; primary PROC was allowed only in case of BRCA-mut. Patients initially received six cycles of olaparib 300 mg b.i.d. (biduum) + intravenous pegylated liposomal doxorubicin (PLD) 40 mg/m2 (PLD40) every 28 days, followed by maintenance with olaparib 300 mg b.i.d. until progression or toxicity. The PLD dose was reduced to 30 mg/m2 (PLD30) due to toxicity. The primary endpoint was progression-free survival (PFS) at 6 months (6m-PFS) by RECIST version 1.1. A proportion of 40% 6m-PFS or more was considered of clinical interest.

RESULTS

From 2017 to 2020, 31 PROC patients were included. BRCA mutations were present in 16%. The median of previous lines was 2 (range 1-5). The overall disease control rate was 77% (partial response rate of 29% and stable disease rate of 48%). After a median follow-up of 10 months, the 6m-PFS and median PFS were 47% and 5.8 months, respectively. Grade ≥3 treatment-related adverse events occurred in 74% of patients, with neutropenia/anemia being the most frequent. With PLD30 serious AEs were less frequent than with PLD40 (21% versus 47%, respectively); moreover, PLD30 was associated with less PLD delays (32% versus 38%) and reductions (16% versus 22%).

CONCLUSIONS

The PLD-olaparib combination has shown significant activity in PROC regardless of BRCA status. PLD at 30 mg/m2 is better tolerated in the combination.

Molecular transduction in receptor-ligand systems by planar electromagnetic fields

The coupling of a ligand with a molecular receptor induces a signal that travels through the receptor, reaching the internal domain and triggering a response cascade. In previous work on T-cell receptors and their coupling with foreign antigens, we observed the presence of planar molecular patterns able to generate electromagnetic fields within the proteins. These planes showed a coherent (synchronized) behavior, replicating immediately in the intracellular domain that which occurred in the extracellular domain as the ligand was coupled. In the present study, we examined this molecular transduction - the capacity of the coupling signal to penetrate deep inside the receptor molecule and induce a response. We verified the presence of synchronized behavior in diverse receptor-ligand systems. To appreciate this diversity, we present four biochemically different systems - TCR-peptide, calcium pump-ADP, haemoglobin-oxygen, and gp120-CD4 viral coupling. The confirmation of synchronized molecular transduction in each of these systems suggests that the proposed mechanism would occur in all biochemical receptor-ligand systems.

Analysis of a clinical process of schizophrenia and other psychoses with a process mining method

Introduction

Clinical pathways (CPWs) are tools used to guide evidence-based healthcare. They translate clinical practice guideline recommendations into clinical processes of care within the characteristics of a healthcare institution. There are few studies about the impact of CPW in the field of Psychosis in terms of adequacy to their recommendations and clinical outcomes.

Objectives

PSYCHSTAGE project has been designed to study the adjustment of psychosis clinical care to a CPW based in a Clinical Practice Guideline according to a clinical staging model in a network of psychiatric services covering 580.000 inhabitants in a University Hospital in Madrid.

Methods

Retrospective and observational study in a sample of 1780 subjects 18 years old or above, diagnosed with schizophrenia and other psychosis. Socio-demographic and clinical variables were collected from clinical records, including ICG, GAF and DAS at the time they were included in the study. Clinical stage was established according to McGorry model at the same time. CPW was analysed in 1,391 subjects with 15,254 care events using a Process mining method. Process discovery, process checking and process enhancement analysis have been used.

Results

Patients were grouped according the clinical stage. 9,2% were in stage 2; 18,5% in 3a; 47% in 3b; 22,1% in 3c and 4,1% in 4. A different CPW is represented for each clinical stage in routine practice. Then, every pathway is compared with the recommendations in the established Psychosis CPW.

Conclusions

Process mining can be a useful tool for the study of CPW in the field of psychosis

Cardiac and placental mitochondrial characterization in a rabbit model of intrauterine growth restriction

BACKGROUND

Intrauterine growth restriction (IUGR) is associated with cardiovascular remodeling persisting into adulthood. Mitochondrial bioenergetics, essential for embryonic development and cardiovascular function, are regulated by nuclear effectors as sirtuins. A rabbit model of IUGR and cardiovascular remodeling was generated, in which heart mitochondrial alterations were observed by microscopic and transcriptomic analysis. We aimed to evaluate if such alterations are translated at a functional mitochondrial level to establish the etiopathology and potential therapeutic targets for this obstetric complication.

METHODS

Hearts and placentas from 16 IUGR-offspring and 14 controls were included to characterize mitochondrial function.

RESULTS

Enzymatic activities of complexes II, IV and II + III in IUGR-hearts (-11.96 ± 3.16%; -15.58 ± 5.32%; -14.73 ± 4.37%; p < 0.05) and II and II + III in IUGR-placentas (-17.22 ± 3.46%; p < 0.005 and -29.64 ± 4.43%; p < 0.001) significantly decreased. This was accompanied by a not significant reduction in CI-stimulated oxygen consumption and significantly decreased complex II SDHB subunit expression in placenta (-44.12 ± 5.88%; p < 0.001). Levels of mitochondrial content, Coenzyme Q and cellular ATP were conserved. Lipid peroxidation significantly decreased in IUGR-hearts (-39.02 ± 4.35%; p < 0.001), but not significantly increased in IUGR-placentas. Sirtuin3 protein expression significantly increased in IUGR-hearts (84.21 ± 31.58%; p < 0.05) despite conserved anti-oxidant SOD2 protein expression and activity in both tissues.

CONCLUSIONS

IUGR is associated with cardiac and placental mitochondrial CII dysfunction. Up-regulated expression of Sirtuin3 may explain attenuation of cardiac oxidative damage and preserved ATP levels under CII deficiency.

GENERAL SIGNIFICANCE

These findings may allow the design of dietary interventions to modulate Sirtuin3 expression and consequent regulation of mitochondrial imbalance associated with IUGR and derived cardiovascular remodeling.

[Planar molecular arrangements aid the design of MHC class II binding peptides]

The coupling between peptides and MHC-II proteins in the human immune system is not well understood. This work presents an evidence-based hypothesis of a guiding intermolecular force present in every human MHC-II protein (HLA-II). Previously, we examined the spatial positions of the fully conserved residues in all HLA-II protein types. In each one, constant planar patterns were revealed. These molecular planes comprise of amino acid groups of the same chemical species (for example, Gly) distributed across the protein structure. Each amino acid plane has a unique direction and this directional element offers spatial selectivity. Constant within all planes, too, is the presence of an aromatic residue possessing electrons in movement, leading the authors to consider that the planes generate electromagnetic fields that could serve as an attractive force in a single direction. Selection and attraction between HLA-II molecules and antigen peptides would, therefore, be non-random, resulting in a coupling mechanism as effective and rapid as is clearly required in the immune response. On the basis of planar projections onto the HLA-II groove, modifications were made by substituting the key residues in the class II-associated invariant chain peptide-a peptide with a universal binding affinity-resulting in eight different modified peptides with affinities greater than that of the unmodified peptide. Accurate and reliable prediction of MHC class II-binding peptides may facilitate the design of universal vaccine-peptides with greatly enhanced binding affinities. The proposed mechanisms of selection, attraction and coupling between HLA-II and antigen peptides are explained further in the paper.

INTERVENCIÓN TEMPRANA EN NIÑOS CON ALTO RIESGO DE DESARROLLAR PARÁLISIS CEREBRAL; UNA REVISIÓN SISTEMÁTICA

El objetivo fue determinar la evidencia existente acerca de la efectividad de intervenciones tempranas sobre el desarrollo motor de niños con alto riesgo de desarrollar una parálisis cerebral. Método: Se realizó una búsqueda literaria en bases de datos y revistas relevantes para el tema (CINAHL, The Cochrane Library, EMBASE, PEDro y PubMed). Los criterios de selección consideran a recién nacidos muy prematuros (

Evaluation of the supplementation of a feed additive as a potential protector against the adverse effects of 2.5 ppm T-2 toxin on growing broiler chickens

ABSTRACT A trial was conducted to evaluate a feed additive containing epoxidase activity from a bacterium (Mycofix-S) as a potential protection against the adverse effects of 2.5 ppm dietary T-2 toxin in male growing broiler chickens. A total of 144 one-day-old Ross 308 male chicks were individually wing-banded and allotted into each of the four experimental groups. Group 1: negative control, no T-2 toxin or additive; group 2: Mycofix-S, 2.5 g/kg; group 3: positive control, 2.5 ppm T-2 toxin; group 4: 2.5 ppm T-2 toxin + 2.5 g/kg Mycofix-S. Feed and water were provided ad libitum for 28 days (days 1 to 28 of age). Each experimental treatment was replicated 6 times, with 6 birds per replicate pen. Response variables included performance parameters, serum activity of alkaline phosphatase (ALP) and amylase, relative weight of selected organs and histology of the upper digestive system. T-2 toxin at 2.5 ppm significantly (P = 0.016) decreased the 28-day body weight gain and cumulative feed intake without affecting feed conversion. The feed additive counteracted these adverse effects. Serum enzyme activities were not significantly (P>0.05) affected for the four experimental groups but when data from the groups receiving T-2 toxin was pooled and compared against the pooled data from groups without the toxin a significant decrease in amylase activity was observed in chickens receiving T-2 toxin. The histological examination of the upper digestive system revealed lesions in mouth, esophagus, proventriculus, gizzard and duodenum in the chickens fed T-2 toxin without the additive. Chickens fed T-2 toxin plus the additive showed lesions in the same tissues except in the duodenum. The results of the present study show that the addition of 2.5 g/kg of the feed additive tested protects against adverse effects on performance and also the integrity of the duodenal mucosa.

Echinostoma caproni (Trematoda): differential in vivo mucin expression and glycosylation in high- and low-compatible hosts

Enhanced mucus production and release appears to be a common mechanism for the clearance of intestinal helminths, and this expulsion is normally mediated by Th2-type immune responses. To investigate the factors determining the expulsion of intestinal helminths, we have analysed in vivo expression of mucin genes at the site of infection in two host species displaying different compatibility with Echinostoma caproni (Trematoda). Surprisingly, a general down-regulation on mucin mRNA expression was detected in low-compatible hosts (rats) coinciding with the development of Th2/Th17 responses and the early rejection of the worms from the intestinal lumen. This suggests the existence of a mechanism by which the parasites can modulate the mucus barrier to favour their survival. In highly compatible hosts (mice), some mucin genes were found to be up-regulated throughout the infection, probably, to protect the intestinal epithelium against the infection-induced inflammation developed in this host species. Moreover, infection-induced changes on mucin glycans were also studied by lectin histochemistry. Similar alterations were detected in the ileum of infected mice and rats, except with SNA lectin, indicating that sylated mucins might play an important role in determining the evolution of the infection in each host species.

Comparison of DNA extraction methods for polymerase chain reaction amplification of guanaco (Lama guanicoe) fecal DNA samples

Feces-based population genetic studies have become increasingly popular. However, polymerase chain reaction (PCR) amplification rates from fecal material vary depending on the species, populations, loci, and extraction protocols. Here, we assessed the PCR amplification success of three microsatellite markers and a segment of the mitochondrial control region of DNA extracted from field-collected feces of guanaco (Lama guanicoe) using two protocols - Qiagen DNA Stool Kit and 2 cetyltrimethylammonium bromide/phenol:chloroform:isoamyl alcohol (2CTAB/PCI) method. Chelex resin treatment to remove inhibitors was also tested. Our results show that the mitochondrial locus was the most difficult to amplify. PCR success rates improved for all markers after Chelex treatment of extracted DNA, and 2CTAB/PCI method (95.83%) appeared to perform slightly better than stool kit (91.67%) for the nuclear markers. Amplification success was significantly influenced by the extraction method, Chelex treatment, and locus (P < 0.001) but not by the freshness of the feces (fresh vs old, P = 0.17). The repeatability levels were high without Chelex treatment (> 0.89), but they decreased slightly after treatment for amplification of nuclear markers and markedly after treatment for amplification of the mitochondrial control region. Thus, we showed that Chelex treatment gives high PCR success, especially for nuclear markers, and adequate DNA extraction rates can be achieved from L. guanicoe feces even from non-fresh fecal material. Although not significant, 2CTAB/PCI method tended to provide higher successful amplification rates on a whole set of samples, suggesting that the method could be particularly useful when using small sample sizes.

Development of regioselective deacylation of peracetylated β-d-monosaccharides using lipase from Pseudomonas stutzeri under sustainable conditions

An efficient deacylation of peracetylated pyranosides has been developed in different biosolvents, catalyzed by Pseudomonas stutzeri lipase, which displayed regiospecific activity towards the anomeric position.

Template assisted electrochemical growth of cobalt nanowires: influence of deposition conditions on structural, optical and magnetic properties

The influence of electrodeposition potential, pH, composition and temperature of the electrolytic bath on the structure of cobalt nanowires arrays electrodeposited into anodic aluminum oxide (AAO) porous membranes is reported. XRD, SEM, and TEM analysis were employed to characterize structural (crystal phase, crystallographic texture, and grain size), and morphological nanowire properties. It was confirmed that at pH 2 the electrodeposition potential has not influence on the preferred crystallographic orientation of the electrochemically grown Co nanowires. At pH 4 the electrodeposition potential controls the growth of cobalt nanowires along some preferential crystallographic planes. The electrolytic pH bath modulates the fcc or hcp phase exhibited by the cobalt nanowires. Single crystalline nanowires with a hcp phase strongly oriented along the (2021) crystallographic plane were obtained at pH 4 and at -1.1 V (vs. Ag/AgCl), a result not previously reported. High electrolytic bath temperatures contributed to improve the single crystalline character of the cobalt nanowires. The presence of chloride anion in the electrolytic bath also influenced on the structural properties of the resulting cobalt nanowires, improving their crystallinity. The optical reflectance of the samples shows a structure in the UV-blue region that can be assigned to the two-dimensional morphology arising in the shape of the almost parallel nanowires. Magnetic measurements showed that different electrodeposition potentials and electrolytic bath pH lead to different magnetic anisotropies on the nanowire array samples.

Pharmacogenetic studies on the antipsychotic treatment. Current status and perspectives

Based on present knowledge, in this work we review the importance of the pharmacogenetic tests in the treatment with antipsychotic drugs. Many associations have been reported between different genetic markers and response to treatment as well as to the appearance of adverse reactions. However, up to now, no "prime" biomarker capable of unequivocally predicting the clinical benefits of a specific treatment or its toxicity has been identified. The use of individual pharmacogenetic markers has been demonstrated to have little clinical utility, and therefore the combination of information obtained from the analysis of different genes seems to be a more promising strategy. Inclusion of pharmacogenetic tests in clinical trials conducted prospectively and that include a large number of cases could, undoubtedly, significantly contribute to the development of individualized medicine protocols.

Evaluation of the ability of a feed additive to ameliorate the adverse effects of aflatoxins in turkey poults

1. A study was conducted to evaluate the possible protective effect of a feed additive containing aluminosilicate and phytogenic substances against the adverse effects of aflatoxins in turkey poults. 2. Dietary treatments (6) were given to turkey poults from d 1 to d 42 of age. From d 1 to 21 the dietary treatments were as follows: 1, negative control, no aflatoxins or feed additive added; 2, feed additive control, 1 kg/t feed additive, no aflatoxins; 3, 250 ppb (microg/kg) aflatoxins, no feed additive; 4, 250 ppb aflatoxins + 1 kg/t feed additive; 5, 500 ppb aflatoxins, no feed additive; and 6, 500 ppb aflatoxins + 1 kg/t feed additive. From d 22 to 42, the dietary concentration of the feed additive was increased from 1 to 2 kg/t in all treatment groups receiving the feed additive (2, 4 and 6), while keeping constant the dietary concentrations of aflatoxins. 3. Aflatoxins at 250 ppb did not cause adverse effects on performance but affected certain toxicopathological parameters. At 500 ppb, adverse effects on performance and several toxicological parameters were observed. 4. Some of the adverse affects were partially or completely overcome by supplementation with the feed additive, including amelioration of the performance parameters, suppression of mortality and correction of the immunological alterations induced by the exposure to the aflatoxins.

Single-crystal growth of nickel nanowires: influence of deposition conditions on structural and magnetic properties

This paper examines the influence of electrodeposition potential, pore size, pH, composition, and temperature of the electrolytic bath on the structure of nickel nanowires arrays electrodeposited into anodic alumina oxide porous membranes. Scanning electron microscopy, X-ray diffraction, and transmission electron microscopy analysis were employed to characterize the structural and morphological properties of the nanowires. Results show that the electrodeposition potential controls the growth of nickel nanowires along some preferential crystallographic planes. At -0.90 V (vs. Ag/AgCl) single crystalline nanowires with a strong (111) orientation were obtained. High temperatures and a moderately acid pH solution contributed to improve the single crystalline character of nanowires. The presence of chloride ions produced polycrystalline nanowires at low temperature and single crystalline nanowires at high temperature. The influence of the electrodeposition potential in their magnetic anisotropies is also reported.

Southeast Asian ovalocytosis is associated with increased expression of Duffy antigen receptor for chemokines (DARC)

The Duffy antigen receptor for chemokines (DARC or Fy glycoprotein) carries antigens that are important in blood transfusion and is the main receptor used by Plasmodium vivax to invade reticulocytes. Southeast Asian ovalocytosis (SAO) results from an alteration in RBC membrane protein band 3 and is thought to mitigate susceptibility to falciparum malaria. Expression of some RBC antigens is suppressed by SAO, and we hypothesized that SAO may also reduce Fy expression, potentiallyleading to reduced susceptibility to vivax malaria. Blood samples were collected from individuals living in the Madang Province of Papua New Guinea. Samples were assayed using a flow cytometry assay for expression of Fy on the surface of RBC and reticulocytes by measuring the attachment of a phycoerythrin-labeled Fy6 antibody. Reticulocytes were detected using thiazole orange. The presence of the SAO mutation was confirmed by PCR. There was a small (approximately 10%) but statistically significant (p=0.049, Mann-Whitney U test) increase in Fy expression on SAO RBC compared with RBC from individuals without this polymorphism: mean Fy expression (mean fluorescence intensity [MFI]) was 10.12 +/- 1.22 for SAO heterozygotes versus an MFI of 8.95 +/- 1.1 for individuals without SAO. For reticulocytes the MFI values were 27.61 +/- 19.12 for SAO heterozygotes and 16.47 +/- 3.81 for controls. SAO is associated with increased and not decreased Fy6 expression so that susceptibility to P. vivax infection is unlikely to be affected.

Geometry dependence of coercivity in Ni nanowire arrays

Magnetic properties of arrays of nanowires produced inside the pores of anodic alumina membranes have been studied by means of vibrating sample magnetometer techniques. In these systems the length of the wires strongly influences the coercivity of the array. A simple model for the coercivity as a function of the geometry is presented which exhibits good agreement with experimental results. Magnetostatic interactions between the wires are responsible for a decrease of the coercive field.

G-protein-coupled receptor heteromers: function and ligand pharmacology

Almost all existing models for G-protein-coupled receptors (GPCRs) are based on the occurrence of monomers. Recent studies show that many GPCRs are dimers. Therefore for some receptors dimers and not monomers are the main species interacting with hormones/neurotransmitters/drugs. There are reasons for equivocal interpretations of the data fitting to receptor dimers assuming they are monomers. Fitting data using a dimer-based model gives not only the equilibrium dissociation constants for high and low affinity binding to receptor dimers but also a 'cooperativity index' that reflects the molecular communication between monomers within the dimer. The dimer cooperativity index (D(C)) is a valuable tool that enables to interpret and quantify, for instance, the effect of allosteric regulators. For different receptors heteromerization confers a specific functional property for the receptor heteromer that can be considered as a 'dimer fingerprint'. The occurrence of heteromers with different pharmacological and signalling properties opens a complete new field to search for novel drug targets useful to combat a variety of diseases and potentially with fewer side effects. Antagonists, which are quite common marketed drugs targeting GPCRs, display variable affinities when a given receptor is expressed with different heteromeric partners. This fact should be taken into account in the development of new drugs.

Association between the serotonin transporter gene and personality traits in borderline personality disorder patients evaluated with Zuckerman-Zuhlman Personality Questionnaire (ZKPQ)

INTRODUCTION

The serotoninergic system seems to be implicated in characteristic symptoms of borderline personality disorder (BPD) such as affective instability, impulsivity or suicide. Some studies suggest an association between serotonin transporter gene (5-HTT) polymorphisms and some BPD symptoms. Short allele (S) of the 5-HTTLPR polymorphism in the promoter region has been shown to be associated with impulsivity, aggressive behavior, anxiety and neuroticism. Of the variable number of tandem repeat (VNTR) polymorphism in intron 2, BPD patients showed higher frequencies of the allele with the 10 repeats. The aim of this study was to determine the association between 5- HTTLPR and VNTR polymorphism of 5-HTT and personality traits in borderline personality disorder.

METHOD

A total of 65 BPD patients diagnosed by means of semi-structured interviews SCID-II and DIB-R were included. Two common polymorphisms of 5-HTT were genotyped: the 5-HTTLPR in the promoter region and VNTR in intron 2. Personality traits were assessed by the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ).

RESULTS

Patients with L allele (L/S or L/L) in the 5-HTTLPR polymorphism showed lower scores on the subscale of liking parties and friends. Patients with the allele with 10 repeat of the VNTR polymorphism, showed lower scores in impulsivity, sensation seeking and in the subscale liking of parties and friends.

CONCLUSIONS

The results suggest a significant association between the 5-HTT gene and some personality traits in BPD. This gene may play a role in the etiology of borderline personality disorder.

Heterodimeric adenosine receptors: a device to regulate neurotransmitter release

Since 1990 it has been known that dimers are the basic functional form of nearly all G-protein-coupled receptors (GPCRs) and that homo- and heterodimerization may play a key role in correct receptor maturation and trafficking to the plasma membrane. Nevertheless, homo- and heterodimerization of GPCR has become a matter of debate especially in the search for the precise physiological meaning of this phenomenon. This article focuses on how heterodimerization of adenosine A1 and A2A receptors, which are coupled to apparently opposite signalling pathways, allows adenosine to exert a fine-tuning modulation of striatal glutamatergic neurotransmission, providing a switch mechanism by which low and high concentrations of adenosine inhibit and stimulate, respectively, glutamate release.

Ontogeny of the immune system of fish

Information on the ontogeny of the fish immune system is largely restricted to a few species of teleosts (e.g., rainbow trout, catfish, zebrafish, sea bass) and has previously focused on morphological features. However, basic questions including the identification of the first lympho-hematopoietic sites, the origin of T- and B-lymphocytes and the acquisition of full immunological capacities remain to be resolved. We review these three main topics with special emphasis on recent results obtained from the zebrafish, a new experimental model particularly suitable for study of the ontogeny of the immune system because of its rapid development and easy manipulation. This species also provides an easy way of creating mutations that can be detected by various types of screens. In some teleosts (i.e., angelfish) the first blood cells are formed in the yolk sac. In others, such as zebrafish, the first hematopoietic site is an intraembryonic locus, the intermediate cell mass (ICM), whereas in both killifish and rainbow trout the first blood cells appear for a short time in the yolk sac but later the ICM becomes the main hematopoietic area. Erythrocytes and macrophages are the first blood cells to be identified in zebrafish embryos. They occur in the ICM, the duct of Cuvier and the peripheral circulation. Between 24 and 30 hour post-fertilization (hpf) at a temperature of 28 degrees C a few myeloblasts and myelocytes appear between the yolk sac and the body walls, and the ventral region of the tail of 1-2 day-old zebrafish also contains developing blood cells. The thymus, kidney and spleen are the major lymphoid organs of teleosts. The thymus is the first organ to become lymphoid, although earlier the kidney can contain hematopoietic precursors but not lymphocytes. In freshwater, but not in marine, teleosts the spleen is the last organ to acquire that condition. We and other authors have demonstrated an early expression of Rag-1 in the zebrafish thymus that correlates well with the morphological identification of lymphoid cells. On the other hand, the origins and time of appearance of B lymphocytes in teleosts are a matter of discussion and recent results are summarized here. The functioning rather than the mere morphological evidence of lymphocytes determines when the full immunocompetence in fish is attained. Information on the histogenesis of fish lymphoid organs can also be obtained by analysing zebrafish mutants with defects in the development of immune progenitors and/or in the maturation of non-lymphoid stromal elements of the lymphoid organs. The main characteristics of some of these mutants will also be described.

Low levels of vitamin B12 and venous thromboembolic disease in elderly men

OBJECTIVES

Hyperhomocysteinaemia is a well-known risk factor for venous thromboembolic disease (VTD). However, it is not clear whether homocysteine (Hc) itself or a related metabolite or a cofactor is primarily responsible for VTD. We carried out a case-control study to investigate whether vitamin concentrations that are involved in the Hc metabolism are associated or not with an elevated risk of VTD.

DESIGN

Case-control study.

METHODS

We measured serum vitamin B12, folate, creatinine and albumin concentrations and plasma Hc concentrations in 101 consecutive patients with VTD, diagnosed by image tests and 101 control subjects, matched for age and sex.

RESULTS

Serum vitamin B12 concentrations were significantly lower in VTD patients than in the control subjects. There were no differences in plasma Hc or serum folate concentrations between the groups. Among the male subgroup aged more than 70 years, serum vitamin B12 concentrations were significantly lower (240.88 +/- 103.07 vs. 421.20 +/- 314.31 pmol L(-1); P = 0.03) and plasma Hc concentrations were significantly higher (13.1 +/- 4.18 vs. 10.56 +/- 3.06 micromol L(-1); P =0.04) in VTD patients than in the control group. On multivariate analysis, in patients aged more than 70 years, serum vitamin B12 concentrations were independently associated with VTD. Compared with the highest quartile of vitamin B12 (>512.6 pmol L(-1)) the odds ratio (OR) for VTD in the lowest quartile (<230.9 pmol L(-1)) was 3.8 (95% CI 1.44-10.18; P = 0.01). In the VTD group, lowest vitamin B12 concentrations (percentile 10 <152.8 pmol L(-1)) were associated with the factor V Leiden mutation (OR = 6.07, 95% CI 0.93-38.55; P = 0.04).

CONCLUSIONS

Measuring vitamin B12 concentrations in elderly males may help in identifying people at risk of venous thromboembolism in our population.

Co phytoavailability for tomato in amended calcareous soils

A plot study was conducted to assess changes in Co phytoavailability for a tomato cultivar grown on an agricultural soil (a Calcic Petrocalcid) amended with sewage sludge, under controlled conditions in South-eastern Spain. The experiment consisted of three main treatment blocks: (A) without organic fertilisation, (B) with addition of 60 tha(-1) and (C) 120 tha(-1) of sewage sludge. For each block (A, B, and C), four levels of Co (0, 50, 100 and 200 mgkg(-1)) were added, as CoCl2. Diethylenetriaminepentaacetic acid, DTPA (0.005 M plus triethanolamine), ammonium acetate (1 N at pH 7), and water extractable fractions of the soils were analysed for all the plots. The time dependent Co accumulation in different parts (roots, stems, leaves, and fruits) of the tomato plants was studied. Soil Co seemed to be mainly in non-available forms, according to the low concentrations found in the water and ammonium acetate extracts, compared to DTPA. The gradient of Co accumulation in tomato plants was root > leaf > stem + branches > fruit, with a concentration in the edible parts ranging between 4 and 25 mg kg(-1). The organic amendment enhanced the plant extraction of Co, this effect being more significant with time. Plant extraction efficiency decreased with increasing Co concentration in the soils. Co in fruit showed the best correlation with all the Co extraction pools in the soil.

Intoxication of Crotalaria pallida seeds to growing broiler chicks

The adverse effects of feeding Crotalaria pallida (CP) seeds to chicks was investigated in a 21-day randomized trial of 4 dietary treatments (control, 1,2 and 3% ground CP seeds). Mortality rates in birds fed 0, 1, 2, and 3% dietary CP were 0, 2.1, 6.2, and 16.7%, respectively. Body weight gain and feed efficiency were adversely affected by all levels of inclusion of CP seeds, but feed intake was decreased only by dietary levels of 2 and 3%. Dietary CP of 2 and 3% increased the relative weight of lung, heart and spleen. Relative liver weight was increased by 2% dietary CP, but decreased by 3% CP. At day 14, serum GGT was increased by 2 and 3% dietary CP; serum ALT was significantly increased by 3% CP. No differences in ALT, AST or GGT were observed at day 21. Dietary levels equal to or greater than 1% CP are toxic for growing broiler chicks.

Assessing changes in Cd phytoavailability to tomato in amended calcareous soils

A plot study was conducted to assess changes in Cd phytoavailability to a tomato cultivar in an agricultural soil in Southeastern Spain amended in two different ways (A and B), under controlled conditions. The experimental soil corresponded to a fine-loamy carbonatic thermic Calcidic Haploxeroll (Soil Survey Staff, Keys to Soil Taxonomy, eighth ed., USDA, Washington, 1998). (A) Soil was amended with a single application of sewage sludge from a municipal source that had a total Cd concentration of 0.5 mg kg(-1) at a rate that represented a final average concentration in the mixture of soil and sludge of less than 50 microg Cd kg(-1). (B) The amendment consisted of the addition of a mineral fertiliser with the same amount of NPK as in the sewage sludge application. The final levels of Cd were supposed to be negligible. A plot series without amendments was also performed (C). DTPA plus triethanolamine, and ammonium acetate extractable fractions in soils were analysed for all the plots. The time-dependent Cd accumulation in different parts of the tomato plants was studied by means of a Cd salt treatment. For each block (A-C) four levels of Cd (0, 3, 30, and 100 mg kg(-1)) were added as CdCl2. There was a significant increase in plant Cd after the initial cropping. Tomato stems, leaves and fruits were analysed separately for Cd determination. Differential Cd distribution and accumulation in tomato parts was detected.

Contribution of engineered electrostatic interactions to the stability of cytosolic malate dehydrogenase

Protein engineering is a promising tool to obtain stable proteins. Comparison between homologous thermophilic and mesophilic enzymes from a given structural family can reveal structural features responsible for the enhanced stability of thermophilic proteins. Structures from pig heart cytosolic and Thermus flavus malate dehydrogenases (cMDH, Tf MDH), two proteins showing a 55% sequence homology, were compared with the aim of increasing cMDH stability using features from the Thermus flavus enzyme. Three potential salt bridges from Tf MDH were selected on the basis of their location in the protein (surface R176-D200, inter-subunit E57-K168 and intrasubunit R149-E275) and implemented on cMDH using site-directed mutagenesis. Mutants containing E275 were not produced in any detectable amount, which shows that the energy penalty of introducing a charge imbalance in a region that was not exposed to solvent was too unfavourable to allow proper folding of the protein. The salt bridge R149-E275, if formed, would not enhance stability enough to overcome this effect. The remaining mutants were expressed and active and no differences from wild-type other than stability were found. Of the mutants assayed, Q57E/L168K led to a stability increase of 0.4 kcal/mol, as determined by either guanidinium chloride denaturalization or thermal inactivation experiments. This results in a 15 degrees C shift in the optimal temperature, thus confirming that the inter-subunit salt bridge initially present in the T.flavus enzyme was formed in the cMDH structure and that the extra energy obtained is transformed into an increase in protein stability. These results indicate that the use of structural features of thermophilic enzymes, revealed by a detailed comparison of three-dimensional structures, is a valid strategy to improve the stability of mesophilic malate dehydrogenases.

Relationships between inhibition constants, inhibitor concentrations for 50% inhibition and types of inhibition: new ways of analysing data

The concentration of an inhibitor that decreases the rate of an enzyme-catalysed reaction by 50%, symbolized i(0.5), is often used in pharmacological studies to characterize inhibitors. It can be estimated from the common inhibition plots used in biochemistry by means of the fact that the extrapolated inhibitor concentration at which the rate becomes infinite is equal to -i(0.5). This method is, in principle, more accurate than comparing the rates at various different inhibitor concentrations, and inferring the value of i(0.5) by interpolation. Its reciprocal, 1/i(0.5), is linearly dependent on v(0)/V, the uninhibited rate divided by the limiting rate, and the extrapolated value of v(0)/V at which 1/i(0.5) is zero allows the type of inhibition to be characterized: this value is 1 if the inhibition is strictly competitive; greater than 1 if the inhibition is mixed with a predominantly competitive component; infinite (i.e. 1/i(0.5) does not vary with v(0)/V) if the inhibition is pure non-competitive (i.e. mixed with competitive and uncompetitive components equal); negative if the inhibition is mixed with a predominantly uncompetitive component; and zero if it is strictly uncompetitive. The type of analysis proposed has been tested experimentally by examining inhibition of lactate dehydrogenase by oxalate (an uncompetitive inhibitor with respect to pyruvate) and oxamate (a competitive inhibitor with respect to pyruvate), and of cytosolic malate dehydrogenase by hydroxymalonate (a mixed inhibitor with respect to oxaloacetate). In all cases there is excellent agreement between theory and experiment.

LYT1 protein is required for efficient in vitro infection by Trypanosoma cruzi

Trypanosoma cruzi invasion of host cells involves several discrete steps: attachment, parasite internalization mediated by recruitment and fusion of host cell lysosomes, and escape from the parasitophorous vacuole to liberate amastigotes to multiply freely in the cytosol. This report describes the initial characterization of the LYT1 gene and the demonstration that the gene product is involved in cell lysis and infectivity. Mutational analysis demonstrated that deletion of LYT1 resulted in attenuation of infection, which was associated with diminished hemolytic activity. Reintroduction of LYT1 restored infectivity in null mutants, confirming the critical role of LYT1 in infection. Additionally, in vitro stage transition experiments with LYT1-deficient lines showed that these parasites converted to extracellular amastigote-like cells and metacyclic trypomastigotes more rapidly than wild-type parasites, suggesting that the diminished infectivity was not a result of the LYT1 deficiency that affected the parasite's ability to complete the life cycle.

DDP1, a heterochromatin-associated multi-KH-domain protein of Drosophila melanogaster, interacts specifically with centromeric satellite DNA sequences

DDP1 is a single-stranded nucleic acid binding protein of Drosophila melanogaster that associates with pericentric heterochromatin. DDP1 contains 15 consecutive KH domains and is homologous to the highly conserved vigilin proteins that, in Saccharomyces cerevisiae, are involved in the control of cell ploidy. DDP1 was identified and purified on the basis of its binding to the pyrimidine-rich C strand of the centromeric Drosophila dodeca-satellite. Here, the interaction of DDP1 with the dodeca-satellite C strand was analyzed in detail. This interaction is sequence specific. In particular, a guanine residue which is highly conserved in natural dodeca-satellite sequences was found to be essential for the efficient binding of DDP1. DDP1 binding was also found to be strongly influenced by the length and extent of secondary structure of the DNA substrate. Efficient DDP1 binding required a minimal length of about 75 to 100 nucleotides and was facilitated by the lack of secondary structure of the substrate. DDP1 also showed a significant affinity for the unstructured pyrimidine-rich strand of the most abundant centromeric Drosophila AAGAG satellite. The stoichiometry of the complexes formed with the dodeca-satellite C strand suggests that, in DDP1, the 15 consecutive KH domains are organized such that they define two nucleic acid binding surfaces. These results are discussed in the context of the possible contribution of DDP1 to heterochromatin organization and function.

Low-flow anesthesia and reduced animal size increase carboxyhemoglobin levels in swine during desflurane and isoflurane breakdown in dried soda lime

After institutional approval, we studied the effect of animal size, anesthetic concentration, and fresh gas flow (FGF) rate on inspired carbon monoxide (CO) and carboxyhemoglobin (COHb) during anesthesia in swine, using soda lime previously dried to 1 +/- 0.1% water content. To ascertain the effect of anesthesia, eight adult pigs were anesthetized with either 1 minimum alveolar anesthetic concentration (MAC) desflurane or isoflurane and, to characterize the effect of the FGF rate, it was doubled in four pigs. To determine the effect of animal size, four small and four large pigs received 1 MAC desflurane or isoflurane, and to determine the effect of the anesthetic concentration, a group of four swine was exposed to 0.5 MAC. CO and COHb concentrations were larger with desflurane (5500 +/- 980 ppm and 57.90% +/- 0.50%, respectively) than with isoflurane (800 ppm and 17.8% +/- 2.14%, respectively), especially in the small animals. Increasing the FGF rate significantly reduced peak CO and COHb concentrations resulting from both anesthetics; however, when each anesthetic was reduced to 0.5 MAC, the concentrations obtained were similar. We conclude that CO intoxication is more severe with desflurane than with isoflurane, that small animals are at higher risk for CO poisoning, and that low FGF can increase COHb concentrations.

IMPLICATIONS

The present study shows that the use of desflurane with desiccated carbon dioxide absorbents in pediatric anesthesia can produce a dangerous carbon dioxide intoxication, especially with low-flow anesthesia.

[Strains of ganciclovir-resistant cytomegalovirus]

BACKGROUND

In countries where the resistance of cytomegalovirus to ganciclovir has been studied, strains resistant to therapeutic doses of this drug have been isolated. When a change in treatment has been impossible the patient has shown bad clinical evolution. The aim of this study was to investigate the presence of these strains in our medium, observe whether the resistances appear in patients previously treated with ganciclovir and determine its implication in the evolution of cytomegalovirus infection.

PATIENTS AND METHODS

One hundred twenty-three stains of cytomegalovirus, isolated during the period 1990-1998, corresponding to the following 94 patients were studied: 17 breast feeding children of healthy parents who were negative controls (sensitive strains), 43 organ transplant recipients, 29 AIDS patients, 2 with other immunodeficiencies and 3 children with intrauterine infection. Seventeen patients were studied due to the insidious course of the infection despite treatment. The remaining were random. The technique used was that of growth inhibition of the strains seeded on different gradients of ganciclovir: 0, 1, 5, 10 and 20 microM. The inoculate consisted in a cellular suspension evaluated according to the degree of viral growth. The strains presenting an inhibitory doses 50% (ID 50%) greater than 10 microM were considered as resistant.

RESULTS

Eighty-two strains presented an ID 50% lower than 5 microM, 24 from 5 to 10 microM and in the 17 remaining strains, corresponding to 12 patients, the ID 50% was greater than 10 microM. The evolution of these latter 12 patients with strains considered to be resistant to ganciclovir was of death in 8. All were immunodepressed and with a history of having previously received ganciclovir. Another currently has a chronic evolution and the three remaining patients, who presented better immunity, became cured. All patients has a chronic evolution and the three remaining patients, who presented better immunity, became cured. All patients had undergone previous treatment with ganciclovir except two: one patient with Wegener disease treated with acyclovir 15 days before, and the other was an infant of an HIV positive mother who had received the drug.

CONCLUSIONS

The presence of cytomegalovirus strains resistant to ganciclovir was confirmed in our patients. The previous use of ganciclovir and, in one case of acyclovir, appears to be implicated in the appearance of resistance. The evolution of the immunodepressed patients with infection by resistant strains was mortal except when their immunity was improved.