Data on the design optimization, indoor characterization and outdoor testing of GaAs/Bifacial Si heterojunction four-terminal photovoltaic systems.

The development of a highly efficient multijunction technology is a key challenge for the future of photovoltaic and for the transition to more renewable energy sources. In this scenario, four-terminal architecture (4T) compared to the classic tandem design allows a large intrinsic robustness to the variations of the solar spectrum, which continuously occur under normal outdoor operation conditions. On the other hand, bifacial solar cells and modules have already proven to be able to increase the energy yield of solar farms at reduced costs. For these reasons, a thorough investigation of the compatibility between these two solutions has been performed by combining a III-V semiconductor with the silicon heterojunction technology in a four-terminal device. This work has been designed in support of the research article entitled "Outdoor performance of GaAs/Bifacial Si Heterojunction four-terminal system using optical spectrum splitting" [1], which showed, through data modeling and an accurate daily analysis of the spectral distribution of solar light, how a four-terminal architecture guarantees the consistency of the bifacial gain and more robust performances than a two-terminal system. Here additional data on the manufacturing, optimization and characterization of the device are presented.

Ig-specific T cell receptor-transgenic T cells are not deleted in the thymus and are functional in vivo.

The mechanisms that induce T cell tolerance to circulating self-proteins are still controversial, and both the deletion and selection of autoreactive T cells have been observed in the thymus of transgenic mouse models. To address the question of the induction of tolerance to circulating self-constituents, a T cell receptor-transgenic mouse specific for the serum protein immunoglobulin (Ig) gamma and (IgG2ab) was generated. The choice of an allotype-specific T cell also allowed the generation of transgenic control mice not expressing the self-antigen. It was found that the transgenic T cells were not deleted in the thymus, did not become tolerant in the periphery, and regulated the function of gamma 2ab-positive B cells as shown by the lack of IgG2ab protein in the serum of the transgenic mice. In spite of this activity in vivo, the transgenic T cells did not proliferate in vitro in response to the allotype-specific peptide. Interestingly, antigen-specific T cell proliferation could be restored if the transgenic mice were previously challenged to induce IgG2ab responses. After this challenge, IgG2ab protein in the serum of the transgenic mice could be partially restored, although still remaining much lower than in control mice. In addition, there was a dramatic increase in serum IgE levels, suggesting that newly generated gamma 2ab-secreting B cells can be induced to switch to IgE in the presence of allotype-specific T cells. These results indicate that Ig-specific T cells may represent a late-acting form of T cell help for the regulation of the IgG2a-to-IgE class switch.

Nef-mediated clathrin-coated pit formation.

The sequence of events leading to clathrin-coated pit (CCP) nucleation on the cell surface and to the incorporation of receptors into these endocytic structures is still imperfectly understood. In particular, the question remains as to whether receptor tails initiate the assembly of the coat proteins or whether receptors migrate into preformed CCP. This question was approached through a dissection of the mechanisms implemented by Nef, an early protein of human and simian immunodeficiency virus (HIV and SIV, respectively), to accelerate the endocytosis of cluster of differentiation antigen type 4 (CD4), the major receptor for these viruses. Results collected showed that: (a) Nef promotes CD4 internalization via an increased association of CD4 with CCP; (b) the Nef-mediated increase of CD4 association with CCP is related to a doubling of the plasma membrane area occupied by clathrin-coated structures; (c) this increased CCP number at the plasma membrane has functional consequences preferentially on CD4 uptake and does not significantly affect transferrin receptor internalization or fluid-phase endocytosis; (d) the presence of a CD4 cytoplasmic tail including a critical dileucine motif is required to induce CCP formation via Nef; and (e) when directly anchored to the cytoplasmic side of the plasma membrane, Nef itself can promote CCP formation. Taken together, these observations lead us to propose that CD4 can promote CCP generation via the connector molecule Nef. In this model, Nef interacts on one side with CD4 through a dileucine-based motif present on CD4 cytoplasmic tail and on the other side with components of clathrin-coated surface domain (i.e., adaptins). These Nef-generated complexes would then initiate the nucleation of CCP.

Acute diarrhea during azathioprine treatment of type I autoimmune hepatitis.

Sporadic descriptions of acute onset of watery diarrhea within a few hours to a few weeks azathioprine administration beginning have been reported, particularly in inflammatory bowel disease patients. This article reports the case of a woman treated with azathioprine because of type I autoimmune hepatitis, who developed acute watery diarrhea after more than two months of therapy. In two occasions the patient reassumed the drug and in a few hours diarrhea recurred. Subsequent 6-mercaptopurine treatment was well tolerated, suggesting that the previous side-effect could be due to the nitroimidazole moiety of azathioprine.

Feline calicivirus strains isolated in Italy.

Feline Calicivirus (FCV) has been recognised as major oral and respiratory pathogen of cats. The high correlation among the field viruses and FCV-F9 serotype has represented the immunological bases for the employ of FCV-F9 serotype as a vaccine for calicivirosis in cats. The aim of this paper was to evaluate, by in vitro neutralization assays, the antigenic correlation among the vaccine F9 and FCV field strains isolated in Sicily (Italy) from cats showing clinical forms referable to calicivirus infection. The results confirm the low correlation between FCV-F9 strain and calicivirus strains spread in the feline population.

Serological survey on Aujeszky's disease, swine influenza and porcine reproductive and respiratory syndrome virus infections in Italian pigs.

Aujeszky's disease (AD), Porcine reproductive and respiratory syndrome (PRRS) and Swine influenza (SI) are among the principal agents of respiratory diseases of pigs. The aim of the study was to determine the prevalence of antibodies to SHV-1, PRRSV and SIV in pigs reared in Sicily. An Enzyme Linked Immunosorbent Assay for the glicoprotein gE of pseudorabies virus, for PRRSV and for SIV was performed. Antibodies against gE of SHV-1 were detected in 171 serum samples (14.6%), whereas PRRSV antibodies occurred at a higher frequency than SHV-1 with 289 (31.1%) samples being positive. The seroprevalence of SIV was found to be 33.3%. This study demonstrated the circulation of ADV, PRRSV and SIV viruses in Sicilian swine population. This is the first report on this topics in Sicily.

Barrett's oesophagus: long-term follow-up after complete ablation with argon plasma coagulation and the factors that determine its recurrence.

BACKGROUND: Argon plasma coagulation seems to be a promising technique for ablation of Barrett's oesophagus, yet few long-term efficacy data are available. AIM: To report on a long-term follow-up and the factors that determine the recurrence of intestinal metaplasia in a cohort of patients with non dysplastic, intestinal type Barrett's oesophagus, after complete ablation of the metaplastic mucosa with argon plasma coagulation. METHODS: Ninety-six patients underwent endoscopic argon plasma coagulation with adequate acid suppression obtained through a continuous omeprazole therapy (50 patients) or through laparoscopic fundoplication (46 patients). Complete ablation was achieved in 94 patients who underwent follow-up. Endoscopic and histological examinations were performed every 12 months. RESULTS: The median follow-up of the patients was 36 months (range 18-98). A recurrence of intestinal metaplasia was found in 17 patients (18%), with an annual recurrence rate of 6.1%. Neither dysplasia, nor adenocarcinoma were found during the follow-up. Through the use of logistic regression analysis, previous laparoscopic fundoplication was associated with a reduced recurrence rate of intestinal metaplasia (odds ratio 0.30, 95% confidence interval 0.10-0.93). CONCLUSIONS: The long-term recurrence of intestinal type Barrett's oesophagus was low after complete ablation with argon plasma coagulation. The control of oesophageal acidity acid exposure with laparoscopic fundoplication seems to reduce the recurrence rate.

Distinct roles for the yeast phosphatidylinositol 4-kinases, Stt4p and Pik1p, in secretion, cell growth, and organelle membrane dynamics.

The yeast Saccharomyces cerevisiae possesses two genes that encode phosphatidylinositol (PtdIns) 4-kinases, STT4 and PIK1. Both gene products phosphorylate PtdIns at the D-4 position of the inositol ring to generate PtdIns(4)P, which plays an essential role in yeast viability because deletion of either STT4 or PIK1 is lethal. Furthermore, although both enzymes have the same biochemical activity, increased expression of either kinase cannot compensate for the loss of the other, suggesting that these kinases regulate distinct intracellular functions, each of which is required for yeast cell growth. By the construction of temperature-conditional single and double mutants, we have found that Stt4p activity is required for the maintenance of vacuole morphology, cell wall integrity, and actin cytoskeleton organization. In contrast, Pik1p is essential for normal secretion, Golgi and vacuole membrane dynamics, and endocytosis. Strikingly, pik1(ts) cells exhibit a rapid defect in secretion of Golgi-modified secretory pathway cargos, Hsp150p and invertase, whereas stt4(ts) cells exhibit no detectable secretory defects. Both single mutants reduce PtdIns(4)P by approximately 50%; however, stt4(ts)/pik1(ts) double mutant cells produce more than 10-fold less PtdIns(4)P as well as PtdIns(4,5)P(2). The aberrant Golgi morphology found in pik1(ts) mutants is strikingly similar to that found in cells lacking the function of Arf1p, a small GTPase that is known to regulate multiple membrane trafficking events throughout the cell. Consistent with this observation, arf1 mutants exhibit reduced PtdIns(4)P levels. In contrast, diminished levels of PtdIns(4)P observed in stt4(ts) cells at restrictive temperature result in a dramatic change in vacuole size compared with pik1(ts) cells and persistent actin delocalization. Based on these results, we propose that Stt4p and Pik1p act as the major, if not the only, PtdIns 4-kinases in yeast and produce distinct pools of PtdIns(4)P and PtdIns(4,5)P(2) that act on different intracellular membranes to recruit or activate as yet uncharacterized effector proteins.

Sac1 lipid phosphatase and Stt4 phosphatidylinositol 4-kinase regulate a pool of phosphatidylinositol 4-phosphate that functions in the control of the actin cytoskeleton and vacuole morphology.

Synthesis and turnover of phosphoinositides are tightly regulated processes mediated by a set of recently identified kinases and phosphatases. We analyzed the primary role of the phosphoinositide phosphatase Sac1p in Saccharomyces cerevisiae with the use of a temperature-sensitive allele of this gene. Our analysis demonstrates that inactivation of Sac1p leads to a specific increase in the cellular levels of phosphatidylinositol 4-phosphate (PtdIns(4)P), accompanied by changes in vacuole morphology and an accumulation of lipid droplets. We have found that the majority of Sac1p localizes to the endoplasmic reticulum, and this localization is crucial for the efficient turnover of PtdIns(4)P. By generating double mutant strains harboring the sac1(ts) allele and one of two temperature-sensitive PtdIns 4-kinase genes, stt4(ts) or pik1(ts), we have demonstrated that the bulk of PtdIns(4)P that accumulates in sac1 mutant cells is generated by the Stt4 PtdIns 4-kinase, and not Pik1p. Consistent with these findings, inactivation of Sac1p partially rescued defects associated with stt4(ts) but not pik1(ts) mutant cells. To analyze potential overlapping functions between Sac1p and other homologous phosphoinositide phosphatases, sac1(ts) mutant cells lacking various other synaptojanin-like phosphatases were generated. These double and triple mutants exacerbated the accumulation of intracellular phosphoinositides and caused defects in Golgi function. Together, our results demonstrate that Sac1p primarily turns over Stt4p-generated PtdIns(4)P and that the membrane localization of Sac1p is important for its function in vivo. Regulation of this PtdIns(4)P pool appears to be crucial for the maintenance of vacuole morphology, regulation of lipid storage, Golgi function, and actin cytoskeleton organization.

Second-messenger regulation of receptor association with clathrin-coated pits: a novel and selective mechanism in the control of CD4 endocytosis.

CD4, a member of the immunoglobulin superfamily, is not only expressed in T4 helper lymphocytes but also in myeloid cells. Receptor-mediated endocytosis plays a crucial role in the regulation of surface expression of adhesion molecules such as CD4. In T lymphocytes p56lck, a CD4-associated tyrosine kinase, prevents CD4 internalization, but in myeloid cells p56lck is not expressed and CD4 is constitutively internalized. In this study, we have investigated the role of cyclic AMP (cAMP) in the regulation of CD4 endocytosis in the myeloid cell line HL-60. Elevations of cellular cAMP were elicited by 1) cholera toxin, 2) pertussis toxin, 3) forskolin and IBMX, 4) NaF, or 5) the physiological receptor agonist prostaglandin E1. All five interventions led to an inhibition of CD4 internalization. Increased cAMP levels did not inhibit endocytosis per se, because internalization of insulin receptors and transferrin receptors and fluid phase endocytosis were either unchanged or slightly enhanced. The mechanism of cAMP inhibition was further analyzed at the ultrastructural level. CD4 internalization, followed either by quantitative electron microscopy autoradiography or by immunogold labeling, showed a rapid and temperature-dependent association of CD4 with clathrin-coated pits in control cells. This association was markedly inhibited in cells with elevated cAMP levels. Thus these findings suggest a second-messenger regulation of CD4 internalization through an inhibition of CD4 association with clathrin-coated pits in p56lck-negative cells.

[Prevalence of Staphylococcus aureus methicillin-resistant (MRSA) among health care workers]. / Prevalenza di Staphylococcus aureus meticillino-resistente (MRSA) tra gli operatori sanitari.

Methicillin-resistant Staphylococcus Aureus (MRSA) is a type of Staphylococcus that is resistant to certain antibiotics. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin. Staphylococcus infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities. The present study was performed to investigate the in vitro activity of oxacillin and other antimicrobial agents against S. aureus strains obtained from nursing personnel. The study included 56 hospital personnel of Universitary Policlinic of Messina. S. aureus strain was isolated in 14 samples (25%); resistent patterns have been studied and results have demonstrated: none methicillin resistant, while 14% oxacillin and tetraciclin resistant. The incidence of methicillin sensitive was 100%, while 86% proved to be sensitive to oxacillin and tetraciclin. In conclusion, the usually hygienic methods (disposable gowns, hygienic hand disinfection after each patients contact, masks use when is a risk of aerosolization of MRSA) are indicate for significantly reducing of these strains. Continuing education programmes can help to increase awareness among hospital staff.

Association between coffee or tea drinking and Barrett's esophagus or esophagitis: an Italian study.

BACKGROUND/OBJECTIVES: Only a few papers have treated of the relationship between Barrett's esophagus (BE) or erosive esophagitis (E) and coffee or tea intake. We evaluated the role of these beverages in BE and E occurrence. SUBJECTS/METHODS: Patients with BE (339), E (462) and controls (619) were recruited. Data on coffee and tea and other individual characteristics were collected using a structured questionnaire. RESULTS: BE risk was higher in former coffee drinkers, irrespective of levels of exposure (cup per day; ⩽1: OR=3.76, 95% CI 1.33-10.6; >1: OR=3.79, 95% CI 1.31-11.0; test for linear trend (TLT) P=0.006) and was higher with duration (>30 years: OR=4.18, 95% CI 1.43-12.3; TLT P=0.004) and for late quitters, respectively (⩽3 years from cessation: OR=5.95, 95% CI 2.19-16.2; TLT P<0.001). The risk of BE was also higher in subjects who started drinking coffee later (age >18 years: OR=6.10, 95% CI 2.15-17.3). No association was found in current drinkers, but for an increased risk of E in light drinkers (<1 cup per day OR =1.85, 95% CI 1.00-3.43).A discernible risk reduction of E (about 20%, not significant) and BE (about 30%, P<0.05) was observed in tea drinkers. CONCLUSIONS: Our data were suggestive of a reduced risk of BE and E with tea intake. An adverse effect of coffee was found among BE patients who had stopped drinking coffee. Coffee or tea intakes could be indicative of other lifestyle habits with protective or adverse impact on esophageal mucosa.

Dendritic cell interactions and cytokine production.

The dendritic cell lineage comprises cells at various stages of functional maturation that are able to induce and regulate the immune response against antigens and thus function as initiators of protective immunity. The signals that determine the given dendritic cell functions depend mostly on the local microenvironment and on the interaction between dendritic cells and microorganisms. These interactions are complex and very different from one pathogen to another; nevertheless, both shared and unique responses have been observed using global genomic analyses. In this review, we have focused on the study of host-pathogen interactions using a genome-wide transcriptional approach with a focus on cytokine family members.

Molecular cloning of a recombinant retrovirus carrying a mutated envAKR-mycMH2 fusion gene immortalizing cells of the monocytic-macrophage lineage.

The VN-11 recombinant retroviruses, originally generated by co-transfection of the avian MH2 and AKRv viral genomes, were molecularly cloned from an infected mouse cell line named N11. The analysis of the proviral genome sequence from one of these recombinants showed a possible envAKR-mycMH2 fusion. Point mutations were also found in this envAKR-mycMH2 gene. The cloned viral genome was co-transfected with the neo gene into the psi 2 packaging cell line. Selected clones were shown to transcribe the viral genome and supernatants from these cultures, containing C-type particles, were used to infect primary cultures from mouse lymphoid tissues and brain. Proliferating macrophages and microglial cell clones were obtained, indicating that various types of cells of the mouse monocytic-macrophage lineage can be immortalized in spite of the absence of selection or special growth conditions.

Fibrin degradation products and impedance plethysmography. Measurements in the diagnosis of acute deep vein thrombosis.

Measurement of fibrin degradation products (FDP) was evaluated in 152 consecutive patients referred because diagnosis of deep vein thrombosis (DVT) was suspected. All patients underwent impedance plethysmography (IPG), and venograms were obtained in 59. Sensitivity and specificity of FDP measurement, using venography as the standard, was 88% and 66%, respectively. Sensitivity and specificity of IPG was 77% and 79%, respectively. Specificity of the two tests combined, when both yielded abnormal results, was 93%. Patients were classified as (1) normal, (2) abnormal, or (3) equivocal on the basis of IPG. A significant difference in mean FDP concentration was found between groups 1 and 2 and groups 2 and 3. An overall correlation was found between degree of abnormality on IPG and FDP concentration. A quantitative determination of FDP is a practical and reliable screening test for DVT and, when used in conjunction with IPG, improves both sensitivity and specificity of the latter.

Effects of nucleoside analog incorporation on DNA binding to the DNA binding domain of the GATA-1 erythroid transcription factor.

We investigate here the effects of the incorporation of the nucleoside analogs araC (1-beta-D-arabinofuranosylcytosine) and ganciclovir (9-[(1,3-dihydroxy-2-propoxy)methyl] guanine) into the DNA binding recognition sequence for the GATA-1 erythroid transcription factor. A 10-fold decrease in binding affinity was observed for the ganciclovir-substituted DNA complex in comparison to an unmodified DNA of the same sequence composition. AraC substitution did not result in any changes in binding affinity. 1H-15N HSQC and NOESY NMR experiments revealed a number of chemical shift changes in both DNA and protein in the ganciclovir-modified DNA-protein complex when compared to the unmodified DNA-protein complex. These changes in chemical shift and binding affinity suggest a change in the binding mode of the complex when ganciclovir is incorporated into the GATA DNA binding site.

Early events in dendritic cell maturation induced by LPS.

Immature dendritic cells (Dcs) are characterised by high antigen uptake ability and poor T-cell stimulatory function. In contrast, mature DCs have a high stimulatory function and poor antigen uptake ability. Inflammatory stimuli induce DC maturation and migration from nonlymphoid tissues to lymphoid organs. We investigated the effect of lipopolysaccharide (LPS) on DC antigen uptake and migratory function at early and late stimulation time points. We observed that the transition from the immature to the mature state is not a progressive itinerary, but it is characterised by precise functional stages. At early time points after LPS stimulation DCs significantly decrease their intrinsic migratory ability and increase the antigen uptake function. Later, around 4 h after LPS activation, DCs show recovery of migratory ability and start to progressively lose their antigen uptake function until the mature stage in which they show poor antigen uptake and migratory activity.

Rabbit monoclonal Fab derived from a phage display library.

Rabbit monoclonal antibodies (RmAb) are not routinely obtained by eukaryotic cell fusion techniques. Therefore, we have applied phage display technology to produce a recombinant rabbit Fab molecule directed against the KLH model antigen. The Fab fragments selected from the rabbit phage display library were subcloned in an expression vector to permit the production of a fusion protein comprising a dimer of bacterial alkaline phosphatase (phoA). This fusion protein was directly produced into the periplasmic space of Escherichia coli. We show that a crude extract containing these conjugates can be used in a direct enzyme immunoassay, as exemplified in the case of the KLH antigen.

Retroviral immortalization of phagocytic and dendritic cell clones as a tool to investigate functional heterogeneity.

We have developed a method to generate immortalized phagocytic and dendritic cell clones from various mouse tissues such as spleen, thymus, brain and bone marrow. The clones were phenotypically characterized and shown to retain the ability to respond to immune or inflammatory signals, e.g., IFN-gamma. Functional cytokine activity and nitric oxide production were maintained in activated macrophages, microglial and dendritic cell clones. Immune functions, such as antigen presentation was exhibited by all clones whereas tissue-specific properties such as the ability to respond to corticotropin-releasing hormone and produce beta-endorphin was shown in microglial cell clones but not in macrophage cell clones, indicating that heterogeneity of cells of the mononuclear-phagocytic lineage can be maintained in vitro after the immortalization procedure. Moreover, the continuous proliferation of the clones could be inhibited by various stimuli and further differentiation of the cells could be achieved in vitro.