P34 ASYMPTOMATIC VENTRICULAR PRE–EXCITATION WITH DISAPPEARANCE DURING EXERTION: ALWAYS AN INDEX OF BENIGNITY?

Introduction

The disappearance of pre–excitation at high heart rates points to a low arrhythmic risk: why resort to electrophysiological studies anyway?

Clinical Case

L.S., a 12–year–old patient, performed an ECG for sports examination with evidence of ventricular pre–excitation from an asymptomatic left lateral accessory route (Fig. A). A 24 h ECG–Holter during training showed the disappearance of the pre–excitation at high frequencies (Fig. B) which is considered a low risk index. The patient underwent a transesophageal electrophysiological study (SETE) during which an effective refractory antegrade period of 228 ms of the pathway was objectified through atrial extrastimuli (*) (Fig. C: drive of atrial stimuli (*) followed by extrastimulus with conduction on an accessory route (E)). In addition, a 1: 1 conduction was observed on the atrial pathway up to at least 270 bpm (222 ms). The antegrade refractory period of the resting path was <250 ms and therefore identified a high–risk condition to be treated with ablation.

Discussion

The disappearance of pre–excitation at high heart rates is usually considered indicative of an accessory pathway with a long refractory period and therefore at low risk, however it must be sudden. According to European guidelines, the execution of invasive studies in asymptomatic patients who are employed in high–risk jobs or competitive sports has a class I B indication, but in the remaining asymptomatic cases the indication is IIa B. The Holter ECG alone or the stress test, with a careless evaluation of the disappearance of the pre–excitation (sudden vs progressive with minimal residual pre–excitation) would have erroneously led to labeling this accessory pathway at low risk. In the left lateral accessory pathways, with the increase of the HR, there can be a disappearance or pseudo–disappearance of the pre–excitation for anatomical reasons (being further away from the SA node) and for an increase in the AV conduction speed, not therefore for a long refractory period of the pathway. SETE is closer to the atrial side of the left accessory pathway and allows to correctly classify the risk.

Conclusion

SETE is a low–cost and minimally invasive method that should be considered as an integral part of the study of patients with asymptomatic ventricular pre–excitation even if non–invasive stratification indicates low risk.

How distant? An experimental analysis of students' COVID-19 exposure and physical distancing in university buildings

Closed university buildings proved to be one of the main hot spots for virus transmission during pandemics. As shown during the COVID-19 pandemic, physical distancing is one of the most effective measures to limit such transmission. As universities prepare to manage in-class activities, students' adherence to physical distancing requirements is a priority topic. Unfortunately, while physical distancing in classrooms can be easily managed, the movement of students inside common spaces can pose high risk of close proximity. This paper provides an experimental analysis of unidirectional student movement inside a case-study university building to investigate how physical distancing requirements impact student movement and grouping behaviour. Results show general adherence with the minimum required physical distancing guidance, but spaces such as corridors pose higher risk of exposure than doorways. Doorway width, in combination with group behaviour, affect the students' capacity to keep the recommended physical distance. Furthermore, questionnaire results show that students report higher perceived vulnerability while moving along corridors. Evidence-based results can support decision-makers in understanding individuals' exposure to COVID-19 in universities and researchers in developing behavioural models in preparation of future outbreaks and pandemics.

Multiple gene expression profiling suggests epithelial dysfunction in polypoid chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous inflammatory disorder resulting from a complex gene-environment interaction. Although its aetiology remains elusive, numerous studies reported gene expression alterations of factors apparently implicated in all aspects of the inflammatory response. However, most investigations are limited, unconfirmed analyses of a single gene. Moreover, studies concerning multiple gene expression analyses, usually on inflammatory mediators (e.g. cytokines), show contrasting outcomes in part due to use of heterogeneous samples or methodologies with limited power. In this scenario, our goal was to simultaneously evaluate the expression of a panel of selected genes (AQP5, MUC5AC, CAV1, LTF, COX2, PGDS, TNFα, TGFβ1, MGB1) potentially involved in CRS inflammatory mechanisms. While most of the samples collected were excluded from the analysis because of poor quality RNA, we were able to demonstrate statistically significant downregulation of the AQP5, CAV1, LTF, MGB1 genes in a specific subset of polypoid CRS (patients without typical comorbidities), which might suggest relevant underlying epithelial dysfunction. Further studies are needed to enrich our knowledge on the pathogenesis of CRS. Forthcoming approaches might utilise next-generation RNA sequencing and comprehensive bioinformatics analyses to better characterise the transcriptome profiles of CRS endotypes.

Inflammatory and oxidative stress biomarkers in alkaptonuria: data from the DevelopAKUre project

OBJECTIVE

The aim of this work was to assess baseline serum levels of established biomarkers related to inflammation and oxidative stress in samples from alkaptonuric subjects enrolled in SONIA1 (n = 40) and SONIA2 (n = 138) clinical trials (DevelopAKUre project).

METHODS

Baseline serum levels of Serum Amyloid A (SAA), IL-6, IL-1β, TNFα, CRP, cathepsin D (CATD), IL-1ra, and MMP-3 were determined through commercial ELISA assays. Chitotriosidase activity was assessed through a fluorimetric method. Advanced Oxidation Protein Products (AOPP) were determined by spectrophotometry. Thiols, S-thiolated proteins and Protein Thiolation Index (PTI) were determined by spectrophotometry and HPLC. Patients' quality of life was assessed through validated questionnaires.

RESULTS

We found that SAA serum levels were significantly increased compared to reference threshold in 57.5% and 86% of SONIA1 and SONIA2 samples, respectively. Similarly, chitotriosidase activity was above the reference threshold in half of SONIA2 samples, whereas CRP levels were increased only in a minority of samples. CATD, IL-1β, IL-6, TNFα, MMP-3, AOPP, thiols, S-thiolated protein and PTI showed no statistically significant differences from control population. We provided evidence that alkaptonuric patients presenting with significantly higher SAA, chitotriosidase activity and PTI reported more often a decreased quality of life. This suggests that worsening of symptoms in alkaptonuria (AKU) is paralleled by increased inflammation and oxidative stress, which might play a role in disease progression.

CONCLUSIONS

Monitoring of SAA may be suggested in AKU to evaluate inflammation. Though further evidence is needed, SAA, chitotriosidase activity and PTI might be proposed as disease activity markers in AKU.

Surface properties of nanocrystalline TiO2 coatings in relation to the in vitro plasma protein adsorption

This study reports on the selective adsorption of whole plasma proteins on hydrothermally (HT) grown TiO2-anatase coatings and its dependence on the three main surface properties: surface charge, wettability and roughness. The influence of the photo-activation of TiO2 by UV irradiation was also evaluated. Even though the protein adhesion onto Ti-based substrates was only moderate, better adsorption of any protein (at pH = 7.4) occurred for the most negatively charged and hydrophobic substrate (Ti non-treated) and for the most nanorough and hydrophilic surface (HT Ti3), indicating that the mutual action of the surface characteristics is responsible for the attraction and adhesion of the proteins. The HT coatings showed a higher adsorption of certain proteins (albumin 'passivation' layer, apolipoproteins, vitamin D-binding protein, ceruloplasmin, α-2-HS-glycoprotein) and higher ratios of albumin to fibrinogen and albumin to immunoglobulin γ-chains. The UV pre-irradiation affected the surface properties and strongly reduced the adsorption of the proteins. These results provide in-depth knowledge about the characterization of nanocrystalline TiO2 coatings for body implants and provide a basis for future studies on the hemocompatibility and biocompatibility of such surfaces.

Distinctive gene expression profiles in Balb/3T3 cells exposed to low dose cobalt nanoparticles, microparticles and ions: potential nanotoxicological relevance

Size-dependent characteristics of novel engineered nanomaterials might result in unforeseen biological responses and toxicity. To address this issue, we used cDNA microarray analysis (13443 genes) coupled with bioinformatics and functional gene annotation studies to investigate the transcriptional profiles of Balb/3T3 cells exposed to a low dose (1 μM) of cobalt nanoparticles (CoNP), microparticles (CoMP) and ions (Co2+). CoNP, CoMP and Co2+ affected 124, 91 and 80 genes, respectively. Hierarchical clustering revealed two main gene clusters, one up-regulated, mainly after Co2+, the other down-regulated, mainly after CoNP and CoMP. The significant Gene Ontology (GO) terms included oxygen binding and transport and hemoglobin binding for Co2+, while the GOs of CoMP and CoNP were related to nucleus and intracellular components. Pathway analysis highlighted: i) mitochondrial dysfunction for Co2+, ii) signaling, activation of innate immunity, and apoptosis for CoNP, and iii) cell metabolism, G1/S cell cycle checkpoint regulation and signaling for CoMP. Unlike ions, particles affected toxicologically-relevant pathways implicated in carcinogenesis and inflammation.

Fish welfare and genomics

There is a considerable public and scientific debate concerning welfare of fish in aquaculture. In this review, we will consider fish welfare as an integration of physiological, behavioral, and cognitive/emotional responses, all of which are essentially adaptative responses to stressful situations. An overview of fish welfare in this context suggests that understanding will rely on knowledge of all components of allostatic responses to stress and environmental perturbations. The development of genomic technologies provides new approaches to this task, exemplified by how genome-wide analysis of genetic structures and corresponding expression patterns can lead to the discovery of new aspects of adaptative responses. We will illustrate how the genomic approach may give rise to new biomarkers for fish welfare and also increase our understanding of the interaction between physiological, behavioral, and emotional responses. In a first part, we present data on expression of candidate genes selected a priori. This is a common avenue to develop molecular biomarkers capable of diagnosing a stress condition at its earliest onset, in order to allow quick corrective intervention in an aquaculture setting. However, most of these studies address isolated physiological functions and stress responses that may not be truly indicative of animal welfare, and there is only rudimentary understanding of genes related to possible cognitive and emotional responses in fish. We also present an overview on transcriptomic analysis related to the effect of aquaculture stressors, environmental changes (temperature, salinity, hypoxia), or concerning specific behavioral patterns. These studies illustrate the potential of genomic approaches to characterize the complexity of the molecular mechanisms which underlies not only physiological but also behavioral responses in relation to fish welfare. Thirdly, we address proteomic studies on biological responses to stressors such as salinity change and hypoxia. We will also consider proteomic studies developed in mammals in relation to anxiety and depressive status which may lead to new potential candidates in fish. Finally, in the conclusion, we will suggest new developments to facilitate an integrated view of fish welfare. This includes use of laser microdissection in the transcriptomic/proteomic studies, development of meta-analysis methods for extracting information from genomic data sets, and implementation of technological advances for high-throughput proteomic studies. Development of these new approaches should be as productive for our understanding of the biological processes underlying fish welfare as it has been for the progress of pathophysiological research.

Immunotoxicity of nanoparticles

The interaction between NPs and immune system has been demonstrated, however, the data available are limited. Among all traits, i.s. hydrophilicity, lipophilicity, catalytic activity, composition, electronic structure, capacity to bind or coat surface species and solubility, the dimension, and consequently the surface area, seems to be the main factor that contribute to the interactions of NPs with biological tissues and immune system in particular. Certain NPs accumulate to regional lymph nodes, where they can be taken up and processed by dendritic cells, interact with self-proteins and, hence, modify their antigenicity and elicit altered immune responses and even autoimmunity. Other NPs may induce allergic sensitization, i.e. allergic contact dermatitis to Pd. In vitro studies demonstrated that NPs can modulate cytokine production toward Th1 (Pl, Pd, Ni, Co) or Th2 (Ti, mw and sw Carbon) production patterns. Some NPs have been linked to allergic sensitization, however, It is unlikely that NPs can act as a hapten inducing a specific IgE production, likely they can act as adjuvant and induce a specific pattern of cytokines, antibody and cells that favor allergic sensitization to environmental allergens. Furthermore, NPs demonstrated pro-inflammatory effects in the lung in experimental animal with increased expression on IL-1beta, MIP-1alpha, MCP-1, MIP-2, keratinocyte chemoattractant, TARC, GM-CSF, MIP-1alpha and activation of the stress-activated MAPKs p38 and JNKs. All considered, the available data suggest that through the elicitation of an oxidative stress mechanism, engineered NPs may contribute to pro-inflammatory disease processes in the lung, particularly allergy.

Antibacterial activity of grape extracts on cagA-positive and -negative Helicobacter pylori clinical isolates

There is considerable interest in alternative/adjuvant approaches for the eradication of Helicobacter pylori using biologically active compounds, especially antioxidants from plants. In the present work, we tested the antioxidant and antimicrobial activities of hydro-alcoholic extracts from Colorino, Sangiovese and Cabernet Sauvignon grape cultivars against H. pylori G21 (cagA-negative, cagA-) and 10K, (cagApositive, cagA+) clinical isolates. We determined the minimum bactericidal concentration (MBC) by incubating strain suspensions in Brucella broth with fetal bovine serum and samples at different concentrations in a final volume of 100 microl in a microaerobic atmosphere. After incubation, subcultures were carried out on Brucella agar plates which were incubated for 3-5 days in a microaerobic environment. The lowest concentration in broth, where the subculture on agar showed complete absence of growth, was considered the MBC.The Colorino extract showed the highest antibacterial activity against G21 strain (MBC=1.35 mg/ml), while Sangiovese and Carbernet MBCs were 4.0 mg/ml ca. H. pylori 10K was only susceptible to Colorino after 48 hours (MBC = 3.57 mg/ml). Resveratrol exhibited the highest antibacterial activity. interestingly, the most pathogenic strain (10K) was less susceptible to both the grape extracts and the isolated compounds. These results suggest that the administration of grape extracts and wine constituents, in addition to antibiotics, might be useful in the treatment of H. pylori infection. Should the reduced susceptibility of 10K strain be extended to all the cagA+ H. pylori isolates, which are endowed with cancer promoter activity, this observation may help explain why the organisms expressing CagA are more closely associated with atrophic gastritis and gastric carcinoma development.

Natural killer cells and gamma/delta T cells in synovial fluid and in peripheral blood of patients with psoriatic arthritis

OBJECTIVE

NK surface markers and gamma/delta TCR antigen are involved in non-MHC-restricted cytotoxicity, which represents a major effector mechanism of the cell-mediated immune response. We evaluated in PsA patients SF and PB lymphocytes expressing these cellular subsets in order to obtain information on the possible role played by them in the disease.

METHODS

We studied 29 PsA and 27 RA patients, as well as 27 healthy controls. In 17 PsA and 16 RA patients with knee joint effusion, analysis of SF was performed. SF and PB lymphocyte analysis was performed by direct dual immunofluorescence flow cytomettry using anti-CD3, anti-CD4, anti-CD8, anti-CD19, anti-TCR-gamma/delta-1 and anti-CD16 and anti-CD56 monoclonal antibodies.

RESULTS

PsA and RA patients had, with respect to controls, lower values (both as percentages and in absolute numbers) of PB T cells expressing gamma/delta TCR. SF Iymphocytes of PsA and RA patients were characterised, as compared to PB lymphocytes, by lower numbers (both in absolute numbers and in relative terms) of NK and NK-T cells. Considering the absolute numbers of the various lymphocyte subsets, a strong correlation was found in PsA SF between gamma/delta T cells and NK (p < 0.0007) or NK-T cells (p < 0.0003), as well as between NK and NK-T cells (p < 0.0019). There was instead no statistically significant correlation among the different SF or PB lymphocytes and the most relevant clinical or serological parameters.

CONCLUSION

This study, analyzing the impairment of different subsets involved in non-MHC-restricted cytotoxicity, suggests that this component of the cell-mediated immune response seems to play a pivotal role in the development of PsA.

Biological effect of the Planktothrix sp. FP1 cyanobacterial extract

Cyanobacteria are common and potentially harmful inhabitants of freshwater and marine environments worldwide. Some waterbloom-forming cyanobacteria are toxic and they may cause animal death and adversely affect human health. A filamentous freshwater cyanobacterium, Planktothrix sp. FP1, was found to be responsible for a toxic algal bloom in Lake Varese (Italy) during August of 1997. In the present study, the biological effects of the Planktothrix sp. FP1 cell extract on Xenopus embryos and on human Peripheral Blood Mononuclear Cells (PBMC) were investigated. FETAX (Frog Embryo Teratogenesis Assay-Xenopus) showed that the cyanobacterial extract had no teratogenic potential, though embryotoxicity was detected (LC(50) 2.944g/l wet weight). The same extract inhibited the proliferation of PBMC stimulated in vitro by phytohemagglutinin (PHA), and strongly interfered with the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma).

Association of surgical specialty and processes of care with patient outcomes for carotid endarterectomy

BACKGROUND AND PURPOSE

Because there is considerable variation in practice patterns and outcomes for carotid endarterectomy (CE), there is a need to study the processes of care that are associated with adverse outcomes. The purpose of this study was to examine the impact of processes of care and surgical specialty on adverse outcomes for CE.

METHODS

A retrospective cohort study based on a voluntary CE registry containing 3644 patients undergoing CE between April 1, 1997, and March 31, 1999, in New York hospitals was used in the study. A multivariable statistical model was used to identify significant independent patient risk factors and to examine the association of processes of care and surgical specialty with outcomes after adjustment for differences in patient risk factors.

RESULTS

The overall adverse outcome (in-hospital death or stroke) rate was 1.84%. After adjustment for differences in 7 patient risk factors that were significantly related to adverse outcomes, the use of >/=1 specific processes of care (eversion endarterectomy, protamine, or shunts) was found to be associated with lower odds of an adverse outcome relative to patients undergoing CE without the processes (OR=0.42, P=0.006). Similarly, patients undergoing surgery performed by vascular surgeons had lower odds of experiencing an adverse outcome (OR=0.36, P=0.009). Processes of care and surgical specialty were highly correlated with one another.

CONCLUSIONS

Processes of care and surgical specialty are significant interrelated determinants of adverse outcome for CE.

Exogenous sphingosine enters Xenopus laevis embryos grown in petri dishes and it is metabolized

Xenopus embryos of different developmental stages were exposed to 0.1 microM [1-3H]sphingosine. Labeled sphingosine was quickly absorbed by Xenopus embryos. The amount of radioactivity absorbed increased with embryo age and appeared to be linearly correlated (R = 0.97) to the embryo surface area. About 45% of the total radioactivity associated to the embryos was found in the skin, 22% in the intestine, 15% in the heart, 12% in the liver and 6% in the brain. A portion of [1-3H]sphingosine entered very rapidly the biosynthetic pathway of sphingolipids; after 30 min of incubation, in fact, only a small amount of free radioactive sphingosine could be detected. Sphingomyelin was the main radioactive sphingolipid synthesized; radioactive ceramide, galactosylceramide and lactosylceramide could also be recognized and quantified. On the contrary, the amount of radioactive gangliosides was hardly detectable. A portion of [1-3H]sphinogosine absorbed by Xenopus embryos (30 to 60% depending on the developmental stage) entered the catabolic pathway producing radioactive phosphoethanolamine that was recycled for the biosynthesis of radioactive phosphatidylethanolamine. This phospholipid was produced mainly in the intestine and in the skin, while sphingomyelin was the main radioactive lipid in the heart, liver and brain.

The chemokine CXCL13 (BCA-1) inhibits FGF-2 effects on endothelial cells

Several chemokines, belonging to both the CXC and CC classes, act as positive or negative regulators of angiogenesis. We sought to investigate the role of CXCL13, B cell-attracting chemokine 1 (BCA-1), also known as B-lymphocyte chemoattractant (BLC), on endothelial cell functions. We tested the effect of CXCL13 on HUVEC chemotaxis and proliferation in the presence of fibroblast growth factor (FGF)-2 and found that such chemokine inhibits FGF-2-induced functions, while is not active by itself. To test whether other FGF-2-mediated biological activities may be affected, we evaluated the ability of CXCL13 to rescue HUVEC from starvation-induced apoptosis, as FGF-2 is a survival factor for endothelial cells, and found that CXCL13 partially inhibits such rescue. Multiple mechanisms may be responsible for these biological activities as CXCL13 displaces FGF-2 binding to endothelial cells, inhibits FGF-2 homodimerization, and induces the formation of CXCL13-FGF-2 heterodimers. Our data suggest that CXCL13 may modulate angiogenesis by interfering with FGF-2 activity.

Molecular cloning of mouse allantoicase cDNA

The uric acid degradation pathway is progressively lost during vertebrate evolution. In mammals, the end product of this catabolic pathway is allantoin and, therefore, no allantoicase should be present in mouse tissues. Surprisingly, we have found an expressed sequence tag (EST) from mouse testis with high similarity to allantoicase. To characterize this transcript, we have completely sequenced the corresponding EST clone insert and found a 1495 bp long cDNA coding for a 414 amino acid long protein. Identities of mouse versus microorganism allantoicases range from 25 to 30%. Identity reaches 54% when compared to Xenopus allantoicase. Among the tested tissues, only testis possesses the allantoicase transcript. Although no deleterious mutations were found in the coding region, no allantoicase activity could be detected in mouse testis.

I-309 binds to and activates endothelial cell functions and acts as an angiogenic molecule in vivo

Several chemokines have been shown to act as angiogenic molecules or to modulate the activity of growth factors such as fibroblast growth factor 2 (FGF-2) and vascular endothelial growth factor (VEGF). The detection of the CC chemokine receptor (CCR) 8 message in human umbilical vein endothelial cells (HUVECs) by reverse transcription- polymerase chain reaction (RT-PCR) and RNase protection assay (RPA), prompted us to investigate the potential role exerted by the CC chemokine I-309, a known ligand of such receptor, in both in vitro and in vivo angiogenesis assays. We show here that I-309 binds to endothelial cells, stimulates chemotaxis and invasion of these cells, and enhances HUVEC differentiation into capillary-like structures in an in vitro Matrigel assay. Furthermore, I-309 is an inducer of angiogenesis in vivo in both the rabbit cornea and the chick chorioallantoic membrane assay (CAM).

Ecotoxicological soil evaluation by FETAX

The frog embryo teratogenesis assay-Xenopus (FETAX) is a powerful and flexible bioassay that makes use of the embryos of the anuran Xenopus laevis. FETAX satisfies the requirements of low cost, reliability and reproducibility and, thanks to its three endpoints (i.e., mortality, teratogenicity and growth inhibition) can detect the xenobiotics that affect embryonic development. In this paper, we have used FETAX to evaluate samples of soils collected in an oil-contaminated area. Embryos were exposed directly to the soil to be tested. Particular attention was devoted to provide a statistical procedure for analysing mortality and malformation data as well as growth retardation.

Human allantoicase gene: cDNA cloning, genomic organization and chromosome localization

Uric-acid-degrading enzymes (uricase, allantoinase, allantoicase, ureidoglycolate lyase and urease) were lost during vertebrate evolution and the causes for this loss are still unclear. We have recently cloned the first vertebrate allantoicase cDNA from the amphibian Xenopus laevis. Surprisingly, we have found some mammalian expressed sequence tags (ESTs) that show high similarity with Xenopus allantoicase cDNA. From a human fetal spleen cDNA library and adult kidney EST clone, we have obtained a 1790 nucleotide long cDNA. The 3' end of this sequence reveals a substantial high identity with the corresponding portion of Xenopus allantoicase cDNA. In contrast, at the 5' end the human sequence diverges from that of Xenopus; since no continuous open reading frame can be found in this region, the hypothetical human protein appears truncated at its N-terminus. We proposed that such a transcript could be due to an incorrect splicing mechanism that introduces an intron portion at the 5' end of human cDNA. Allantoicase cDNA is expressed in adult testis, prostate, kidney and fetal spleen. By comparison with available genomic sequences deposited in database, we have determined that the human allantoicase gene consists of five exons and spans 8kb. We have also mapped the gene in chromosome 2.

Down-regulation of natural killer cells and of gamma/delta T cells in systemic lupus erythematosus. Does it correlate to autoimmunity and to laboratory indices of disease activity?

A depletion of natural killer (NK) cells seems to play a role in the course of systemic lupus erythematosus (SLE) whereas the possible involvement in this disease of T cell receptor (TCR) gamma/delta positive T cells is still debated. The aim of this study was to evaluate the peripheral blood mononuclear cells (PBMCs) that express NK surface markers CD16 and CD56 or gamma/delta TCR antigen in 58 SLE patients, investigating the possible role of these cell subsets involved in non-MHC-restricted cytotoxicity and their relationship with the main clinical and laboratory parameters. SLE patients had, with respect to controls, considerably decreased values of NK cells (P<0.0004 in percentage and P<0.00004 as absolute number), of non-MHC-restricted T cytotoxic lymphocytes (P<0.007 and P<0.0015, respectively) and of T cells expressing gamma/delta TCR (P<0.02 and P<0.004, respectively). The absolute numbers of these cell subsets positively correlated to each other (P<0.009). gamma/delta T cells inversely correlated with higher ESR values, both percentually (P<0. 006; r=-0.367) and in absolute number (P<0.009; r=-0.350). Moreover, the percentage values of this cell subset inversely correlated with higher levels of CRP (P<0.05; r=-0.256) while SLE patients with anti-SSB/La antibodies had lower values of T lymphocytes bearing gamma/delta TCR, both as percentage (P<0.008) and as absolute number (P<0.02). Our study indicates that non-MHC-restricted cytotoxicity, shared by NK, NK-like and gamma/delta T cells, may be down-regulated in SLE patients, owing to a significant reduction of these PBMC subsets. These specific cell subset impairments seem to affect only some aspects of the disease, suggesting a weakening of the regulatory properties of these cells in the control of different immunological and inflammatory features of SLE, that could be of importance in its clinical expression.

Xenopus allantoicase: molecular cloning, enzymatic activity and developmental expression

Allantoicase is one of the enzymes of the purine degradation pathway and, interestingly, it appears to be lost, together with uricase and allantoinase, during mammalian evolution. Only allantoicases from the ascomycetes S. pombe, S. cerevisiae, and N. crassa have already been cloned, although the activity has been reported also in fishes and amphibians. By screening a cDNA expression library of Xenopus liver, we have cloned a 1491-bp-length cDNA coding for a 389 amino acid protein that shows an high similarity with the enzyme allantoicase. We have found that allantoicase mRNA is abundantly expressed in kidney and liver, but at much lower level is also present in brain, testis, intestine, and lung. We have detected enzymatic activity in crude extract from kidney, liver, and lung; we have also determined kinetic parameters (K(m) = 8.44 mM, V(max) = 6. 94 micromol min(-1) per mg protein) in kidney. During embryo development, we have detected allantoicase transcript and activity starting from 1 and 5 days after fertilization, respectively.

Tuberculin skin reactivity in Italian military recruits tested in 1996-1997

In 1996-1997 data was collected and a Mantoux tuberculin test performed in 2882 Italian military recruits aged 18-23 years in order to establish the prevalence of tuberculin reactivity. In addition, the annual risk of infection, defined as the probability that a non-infected individual would be infected during the following year, was calculated. Of the 2882 recruits, 513 had received a BCG vaccination, the remaining 2369 had not. The overall prevalence of subjects with a tuberculin skin reaction size >5 mm (the cut-off point for positivity corresponding to the antimode in the reaction size frequency curve) was 6.1% (144/2369). The prevalence of skin reactivity increased with age but remained similar when related to area of residence, duration of father's school education and family size. The same general trend was observed if the standard pre-established cut-off point of 10 mm was used. In this case the overall prevalence of a positive skin reaction was 4% (95/2369). The annual risk of infection was 0.3% for a prevalence of tuberculin skin reactivity of 6.1% (cut-off point 5 mm) and 0.19% for a prevalence of 4% (cut-off point 10 mm). Analysis of the population sample vaccinated with BCG showed a lack of correlation between the positive reaction after vaccination reported retrospectively by the subject and the current skin reaction observed by the physician in this study (K = 0.254). Moreover, a significant difference was observed between the skin reaction in subjects vaccinated with BCG in 1993-1994 (average size 12.5 mm) and that of subjects vaccinated in 1995-1996 (average size 10.1 mm, P<0.01), probably as a consequence of mycobacteria circulating in the general population which act as a natural booster in people already vaccinated with BCG. A booster effect of tuberculin in Mantoux assays also cannot be excluded.

Induction of natural killer cell activity and perforin and granzyme B gene expression following continuous culture of short pulse with interleukin-12 in young and old mice

Anticancer immunotherapy with cytokines is often limited by the occurrence of severe toxicity, particularly in older age groups, which are characterized by a reduced tolerance to antineoplastic therapies. We, and others, have recently demonstrated the efficacy of pulsing procedures with IL-2 as a new therapeutic strategy to induce antitumor cytotoxic cells. The aim of this paper was to evaluate the effect of IL-12 on NK cell activity in young and old mice and to investigate the possibility of inducing NK cytotoxicity and perforin and granzyme B gene expression through a brief exposure of spleen lymphocytes from young and old mice to IL-12. Pulsed lymphocytes were compared with non-pulsed cells cultured continuously in IL-12. IL-12 was able to boost both endogenous and IL-2-induced NK cell activity in young and old mice; the levels of cytotoxicity were lower in old than in young animals although the relative increase of IL-12 plus IL-2 versus IL-2 alone was greater for old mice. Comparable levels of NK cell activity were obtained in pulsed (5 min-1 hour) and non-pulsed lymphocytes from both young and old mice after one or three days of culture. The efficacy of the pulsing procedure was evident in both endogenous and IL-2-induced NK cytotoxicity. The mRNA encoding perforin and granzyme B were markedly and similarly enhanced in both IL-12-pulsed and non-pulsed lymphocytes in comparison with control cells. The results demonstrate the effectiveness of IL-12 pulsing in inducing antitumor cytotoxic cells, suggesting the possibility of using IL-12 pulsing, alone or in combination with IL-2, in the immunotherapy of both young and old subjects.

[New aspects in the evaluation of risk factors for fetal development]

Much knowledge concerning the effects of xenobiotics on prenatal development derive from experimental studies, which are generally performed on laboratory animals according to standardized protocols. Conventional in vivo studies should be integrated by other models within a scientifically-based risk assessment strategy. The paper reviews a few in vitro and/or in vivo approaches: identification of critical effects through the characterization of the pathogenesis as well as the use of dose-response relationships; alternative models to identify reproductive risks from single substances and/or mixtures present in the environment; interactions between in vitro and in vivo studies in the risk assessment of solvents: embryonic metabolism in teratogenicity; interactions between experimental and epidemiological studies to understand the pathogenesis of embryolethality; risk assessment of the effects of prenatal exposure to ionizing radiations.

[Evaluation and quantification of biologic risk in the hospital setting with ATP determination on work surfaces]

The purpose of this study was to establish whether a method of determining ATP levels using the HY-Lite system could be reliably applied in the various hospital workplaces. We estimated the correlation between ATP levels and the number of C.F.U. (Colony Forming Units), observed correlation r = 0.96. We established hygienically acceptable values for each environment, and drew up reference tables. The study reveals that conditions of high bacterial and fungine contamination can occur, albeit the agents are not normally pathogenic is so far as they consist of common environmental pollutants. Consequently, these results emphasize the need to apply strict sanitization and hygienic measures, that health workers must be suitably trained to deal with follow. The results of the sampling appear to suggest that condition of potential biological risk for workers are largely due to incorrect work procedure in workplaces where pathologic agents are present.

D-aspartate oxidase is present in ovaries, eggs and embryos but not in testis of Xenopus laevis

D-aspartate oxidase (DASPO) is an FAD dependent flavoprotein which catalyzes the oxidative deamination of D-aspartate using oxygen as electron acceptor. D-aspartate and DASPO are supposed to be involved in the regulation of the central nervous system and in the animal development. This manuscript describes for the first time the presence of DASPO in Xenopus laevis fertilized eggs and embryos and suggests a different tissue distribution of this enzyme in adult male and female animals. In particular, by means of 2D-electrophoresis and affinity purified specific anti-DASPO antibodies, the enzyme was localized in fertilized eggs of X. laevis and in ovaries of adult animals but it was shown to be absent in the testis suggesting a gender specific expression. The protein from Xenopus ovaries has been purified by means of immunoprecipitation and it has M(r) of 30 kDa and pI of 8.1.

The equine herpesvirus 2 E1 open reading frame encodes a functional chemokine receptor

Several herpesviruses contain open reading frames (ORFs) that encode potential homologs of eucaryotic genes. Equine herpesvirus 2 (EHV-2) is a gammaherpesvirus related to other lymphotropic herpesviruses such as herpesvirus saimiri and Epstein-Barr virus. The E1 ORF of EHV-2, a G protein-coupled receptor homolog, shows 31 to 47% amino acid identity with known CC chemokine receptors. To investigate whether E1 may encode a functional receptor, we cloned the E1 ORF and expressed it in stably transfected cell lines. We report here the identification of the CC chemokine eotaxin as a functional ligand for the EHV-2 E1 receptor. Chemokines are likely to play a role in the regulation of immune functions in equine hosts during EHV-2 infection and, via interaction with E1, may affect viral replication and/or escape from immune responses.

Two-dimensional protein maps of xenopus eggs and embryos at different developmental stages

Protein expression during the early development of Xenopus has been followed by 2D-polyacrylamide gel electrophoresis (PAGE). The analysis of two-dimensional maps of eggs and embryos at different stages of development has allowed the separation of more than 2000 spots. Identification of numerous polypeptides was obtained in four different ways: (1) immuno-blotting; (2) amino terminal sequence after blotting on to PVDF membranes; (3) comigration; and (4) assignment in comparison with proteins separated by 2D techniques on reference maps such as human liver, red blood cells, plasma and cerebrospinal fluid reported in the Swiss 2D-PAGE Data Base. The maps presented in this report are a step toward the study of the protein expression in Xenopus eggs and embryos and may be a powerful working tool since Xenopus embryos are popular models for the study of development.

Glycolipid glycosyltransferase activities during early development of Xenopus: effect of retinoic acid

Retinoic acid (RA) plays an important role in differentiation stage in which it also influences glycoconjugate metabolism. Previous work in our laboratory has shown that treatment with RA modifies glycolipid synthesis and distribution in total Xenopus embryos during development. In this study we have investigated the activity of the following anabolic enzymes involved in glycolipid biosynthesis: sialyltransferase-1 (SAT-1), GM3(beta1, 4)-N-acetylgalactosaminyltransferase (GalNAcT-1) and LacCer(beta1, 3)N-acetylglucosaminyltransferase (GlcNAcT-1). These enzymes are located at the branching point of lactosylceramide (Lc(2)) metabolism. Enzyme activities were assayed after treatment with different doses of RA added exogenously to the medium during the first 7 days of Xenopus embryo development. Our results show that RA activates GlcNAcT-1, the enzyme that drives Lc(2)to the glycolipids of the lacto-series, and SAT-1 that inserts Lc(2)in the ganglio-series pathway. These data support our previous analysis of glycolipid pattern in Xenopus embryos after RA treatment (Rizzo et al., 1995;Cell Biol Int19: 895-901) indicating a possible correlation between the distribution of glycolipids and the enzymes involved in their metabolism.

Effect of maternal diet on the distribution of phospholipids and their fatty acid composition in Xenopus laevis embryos

We determined the total phospholipid content, the percentage distribution of different phospholipid classes and their fatty acid composition in 6-day-old embryos obtained from Xenopus laevis females fed on two different diets. A first group of females was fed on beef liver, and a second one was nourished with commercial fish food very rich in omega-3 fatty acids. The embryos showed different patterns of phospholipids that had dissimilar fatty acid compositions. Phosphatidylinositol content was particularly affected. Due to the functional roles of this phospholipid as part of the transmembrane signaling machinery, it is possible to hypothesize that maternal diet might influence cell metabolism in amphibian embryos.

The viral chemokine macrophage inflammatory protein-II is a selective Th2 chemoattractant

Kaposi's sarcoma (KS) lesions are characterized by a prominent leukocyte infiltrate composed of mononuclear phagocytes and T cells. KS-associated CD4(+) and CD8(+) cells showed predominantly a type II cytokine profile. The CC chemokine viral macrophage inflammatory protein-II (vMIP-II) encoded by the KS-associated herpes virus 8 was a selective chemoattractant for T helper 2 (Th2 cells) and for monocytes, whereas it was inactive on other leukocytes, including Th1 cells, dendritic cells, and natural killer (NK) cells. vMIP-II was an agonist for CCR8, a chemokine receptor selectively expressed on CD4(+) and CD8(+) cells with a type II cytokine profile. Hence, vMIP-II has agonist activity for a chemokine receptor (CCR8), which is preferentially expressed on polarized Th2 cells. The capacity of vMIP-II to attract type II T cells selectively is likely to be a component of the virus strategy to subvert the host immune response.

Identification of the CC chemokines TARC and macrophage inflammatory protein-1 beta as novel functional ligands for the CCR8 receptor

Chemokines are key molecules in directing leukocyte migration toward sites of inflammation. We have previously cloned a putative CC chemokine receptor gene, TER1, whose expression is restricted to lymphoid tissues and cell lines. Recently, this receptor has been shown to signal in response to the human CC chemokine I-309 and thus it has been renamed CCR8 according to the current nomenclature. In the present study, we report the identification of the CC chemokines thymus and activation-regulated cytokine (TARC) and macrophage inflammatory protein-1 beta (MIP-1 beta) as CCR8 ligands, as they induce chemotaxis in CCR8 Jurkat stable transfectants. Furthermore, we have generated a polyclonal antiserum that is able to recognize the CCR8 molecule in transfectant lysates. The pattern of CCR8 mRNA expression and the functional effects exerted by its ligand suggest that the triggering of this receptor may regulate multiple functions including activation, migration and proliferation of lymphoid cells.

Functional role of alpha4beta1 and alpha5beta1 integrin fibronectin receptors expressed on adriamycin-resistant MCF-7 human mammary carcinoma cells

Cytofluorimetric and reverse-transcription polymerase chain reaction (RT-PCR) analysis showed that adriamycin-resistant (ADRR), but not sensitive (WT), MCF-7 human mammary carcinoma cell lines express alpha4beta1 and alpha5beta1 integrins. ADR(R) cells adhere to fibronectin (FN), and only alpha5beta1 is involved in cell adhesion to this glycoprotein, while alpha4beta1 mediates cell binding to the cellular counter-receptor VCAM-1. Proliferation assays showed that FN, but not VCAM-1, delivers a mitogenic signal to quiescent ADR(R) MCF-7 cells. The activating signal is mediated by alpha5beta1, since cell proliferation is inhibited in the presence of RGD peptide or specific antibody. Cell cycle analysis demonstrated that cell/FN interaction induces the re-entry of ADR(R) MCF-7 into S phase, and prevents them from undergoing serum deprivation-induced apoptosis. Our data suggest that the presence of alpha5beta1 on the resistant cells enables them to draw advantage from FN for both cell growth and survival.

Isolation and chromosomal localization of GPR31, a human gene encoding a putative G protein-coupled receptor

The screening of a human genomic library with a chemokine receptor-like probe allowed us to obtain a putative member of the G protein-coupled receptor gene (GPCR) family, designated GPR31. Its deduced amino acid sequence encodes a polypeptide of 319 amino acids that shares 25-33% homology with members of the chemokine, purino, and somatostatin receptor gene families. Amino acid sequence comparison reveals that the best match in the protein databases is with the human orphan GPCR called HM74 (33% identity). Southern genomic analysis of the GPR31 gene shows a hybridization pattern consistent with that of a single-copy gene. Using fluorescence in situ hybridization, we have determined the chromosomal and regional localization of the GPR31 gene at 6q27. The GPR31 mRNA is expressed at low levels by several human cell lines of different cellular origins. The phylogenetic analysis suggests that the GPR31 receptor may represent a member of a new GPCR subfamily.

Activities of glycolipid glycosyltransferases and sialidases during the early development of Xenopus laevis

The activities of glycosyltransferases and sialidases, together with the ganglioside content and distribution, have been extensively studied in mammals, while the informations on tissues of other animals, including amphibian, are scarce. In this paper we present data on the activities of SAT-1, SAT-2, SAT-4, SAT-5, GlcNAcT-1, GalNAcT-1, GalT-6, and sialidases studied in Xenopus laevis embryos at different stages of development. The highest activity was found at days 4 and 5 of embryogenesis for glycosyltransferases and sialidases respectively; a tentative correlation between the in vitro activity of these enzymes and the content of neutral and acidic glycolipids is discussed.

Tissue and developmental specificity of a polysialo-ganglioside species in the amphibian Xenopus

Xenopus embryos contain a considerable amount of a polysialo-ganglioside not yet fully characterized; in this paper, we will refer to it as ganglioside XI. Preliminary experiments indicate asialo-GMI as the core structure of the ganglioside XI and palmitic and oleic acid as the fatty acids of the ceramide moiety. Further analyses by comparative 2D-TLC with adult fish and chick embryo brains indicate the pentasialilated ganglioside GP1c as the possible structure of XI. In the adult Xenopus, XI characterizes the ganglioside pattern of the central nervous system while is absent in all the other tested tissues. At least two other more polar (presumably richer in sialic acid) bands are often visible under XI, both in embryos and in brain and spinal cord tissues of adult Xenopus. The persistence of polysialo-gangliosides in the brain and spinal cord of adult amphibians could serve to guarantee a proper functioning of the central nervous system at low body temperature.

Molecular cloning of TER1, a chemokine receptor-like gene expressed by lymphoid tissues

Several chemokine receptors have been cloned and shown to belong to a superfamily of seven transmembrane, G protein-coupled receptors. We report here the molecular cloning of TER1, a novel human chemokine receptor-like gene. The amino acid sequence deduced from the TER1 cDNA shows 43, 40, 40, and 39% identity to CCR4, CCR5, CCR1, and CCR2B beta chemokine receptors, respectively. By the use of fluorescent in situ hybridization, we have mapped the TER1 gene to chromosome 3p21, clustered with other chemokine receptor genes. By Northern blot analysis, TER1 mRNA is found to be expressed in the thymus, spleen, and at barely detectable levels in peripheral blood lymphocytes. Moreover, TER1 message in abundant in the NK cell line NK3.3 and in the T cell line MOLT-4. The restricted TER1 expression in cells and tissues of the lymphoid lineage suggests that this receptor may play a role in regulating immune functions.

Molecular cloning of TER1, a chemokine receptor-like gene expressed by lymphoid tissues

Several chemokine receptors have been cloned and shown to belong to a superfamily of seven transmembrane, G protein-coupled receptors. We report here the molecular cloning of TER1, a novel human chemokine receptor-like gene. The amino acid sequence deduced from the TER1 cDNA shows 43, 40, 40, and 39% identity to CCR4, CCR5, CCR1, and CCR2B beta chemokine receptors, respectively. By the use of fluorescent in situ hybridization, we have mapped the TER1 gene to chromosome 3p21, clustered with other chemokine receptor genes. By Northern blot analysis, TER1 mRNA is found to be expressed in the thymus, spleen, and at barely detectable levels in peripheral blood lymphocytes. Moreover, TER1 message in abundant in the NK cell line NK3.3 and in the T cell line MOLT-4. The restricted TER1 expression in cells and tissues of the lymphoid lineage suggests that this receptor may play a role in regulating immune functions.