SARS-CoV-2 Igg seroprevalence in IBD patients treated with biologics: first vs. second pandemic wave in a prospective study.

OBJECTIVE: In a prospective study, SARS-CoV-2 IgG seroprevalence was assessed during the second pandemic wave (W2) in a cohort of Inflammatory Bowel Disease (IBD) patients using biologics. The secondary aim was to compare, in the same cohort, the frequency of seropositivity and of COVID-19 during the second vs. the first (W1) wave. PATIENTS AND METHODS: From November 2020 to March 2021, SARS-CoV-2 IgG seropositivity and the prevalence of COVID-19 were assessed in a cohort of IBD patients using biologics already studied at W1. INCLUSION CRITERIA: age ≥ 18 years; diagnosis of IBD; follow-up; written consent. EXCLUSION CRITERIA: SARS-CoV-2 vaccination. Risk factors for infection, compatible symptoms, history of infection or COVID-19, nasopharyngeal swab test were recorded. Data were expressed as median [range]. The χ2 test, Student's t-test, logistic regression analysis was used. RESULTS: IBD cohort at W1 and W2 included 85 patients: 45 CD (52.9%), 40 UC (47.1%). When comparing the same 85 patients at W2 vs. W1, a higher SARS-CoV-2 seroprevalence at W2 was at the limit of the statistical significance (9.4% vs. 2.3%; p=0.05). The prevalence of COVID-19 at W2 vs. W1 was 3.5% (3/85) vs. 0% (0/85) (p=0.08). Contacts with COVID-19 patients and symptoms compatible with COVID-19 were more frequent at W2 vs. W1 (18.8 % vs. 0%; p=0.0001; 34.1% vs. 15.3%; p=0.004). At W2, history of contacts and new onset diarrhea were more frequent in seropositive patients [4/8 (50%) vs. 12/77 (15.6%); p=0.01 and 4/8 (50%) vs. 2/77 (2.6%); p=0.0001]. At W2, the risk factors for seropositivity included cough, fever, new onset diarrhea, rhinitis, arthromyalgia, dysgeusia/anosmia at univariate (p<0.05), but not at multivariate analysis. History of contacts was the only risk factor for seropositivity at univariate (p=0.03), but not at multivariate analysis (p=0.1). CONCLUSIONS: During W2, characterized by a high viral spread, IBD and biologics appeared not to increase the prevalence of SARS-CoV-2 infection or COVID-19 disease. New onset diarrhea mimicking IBD relapse may be observed in patients with SARS-CoV-2 infection.

Latency correction of event-related potentials between different experimental protocols.

OBJECTIVE: A fundamental issue in EEG event-related potentials (ERPs) studies is the amount of data required to have an accurate ERP model. This also impacts the time required to train a classifier for a brain-computer interface (BCI). This issue is mainly due to the poor signal-to-noise ratio and the large fluctuations of the EEG caused by several sources of variability. One of these sources is directly related to the experimental protocol or application designed, and may affect the amplitude or latency of ERPs. This usually prevents BCI classifiers from generalizing among different experimental protocols. In this paper, we analyze the effect of the amplitude and the latency variations among different experimental protocols based on the same type of ERP. APPROACH: We present a method to analyze and compensate for the latency variations in BCI applications. The algorithm has been tested on two widely used ERPs (P300 and observation error potentials), in three experimental protocols in each case. We report the ERP analysis and single-trial classification. MAIN RESULTS: The results obtained show that the designed experimental protocols significantly affect the latency of the recorded potentials but not the amplitudes. SIGNIFICANCE: These results show how the use of latency-corrected data can be used to generalize the BCIs, reducing the calibration time when facing a new experimental protocol.

Task-dependent signal variations in EEG error-related potentials for brain-computer interfaces.

OBJECTIVE: A major difficulty of brain-computer interface (BCI) technology is dealing with the noise of EEG and its signal variations. Previous works studied time-dependent non-stationarities for BCIs in which the user's mental task was independent of the device operation (e.g., the mental task was motor imagery and the operational task was a speller). However, there are some BCIs, such as those based on error-related potentials, where the mental and operational tasks are dependent (e.g., the mental task is to assess the device action and the operational task is the device action itself). The dependence between the mental task and the device operation could introduce a new source of signal variations when the operational task changes, which has not been studied yet. The aim of this study is to analyse task-dependent signal variations and their effect on EEG error-related potentials. APPROACH: The work analyses the EEG variations on the three design steps of BCIs: an electrophysiology study to characterize the existence of these variations, a feature distribution analysis and a single-trial classification analysis to measure the impact on the final BCI performance. RESULTS AND SIGNIFICANCE: The results demonstrate that a change in the operational task produces variations in the potentials, even when EEG activity exclusively originated in brain areas related to error processing is considered. Consequently, the extracted features from the signals vary, and a classifier trained with one operational task presents a significant loss of performance for other tasks, requiring calibration or adaptation for each new task. In addition, a new calibration for each of the studied tasks rapidly outperforms adaptive techniques designed in the literature to mitigate the EEG time-dependent non-stationarities.

Developmental expression of Cu,Zn superoxide dismutase in Xenopus. Constant level of the enzyme in oogenesis and embryogenesis.

cDNA clones for Xenopus laevis Cu,Zn-superoxide dismutase were isolated, sequenced and used as probes to study the expression of the corresponding gene during oogenesis and embryogenesis; Cu,Zn-superoxide dismutase activity was also monitored throughout development. It has been observed that its mRNA is actively synthesized during early oogenesis, reaching a maximum level at stage II, and is utilized through oogenesis. This results in an accumulation of enzyme activity during oocyte growth, paralleling the accumulation of the several other cellular components which are stored in the oocyte to be utilized later on by the developing embryo. In fact, Cu,Zn-superoxide dismutase activity is present at an approximately constant level until late embryonic development, while its mRNA disappears soon after fertilization to be accumulated again only during the last part of embryogenesis. This developmental expression behaviour can be viewed as typical of an housekeeping function and suggests that Cu,Zn-superoxide dismutase activity is a constant need of the cell rather than being subject to regulation by oxygen metabolism.

Primary structure from amino acid and cDNA sequences of two Cu,Zn superoxide dismutase variants from Xenopus laevis.

A mixture of two different amino acid sequences was discovered in Cu,Zn superoxide dismutase purified from the amphibian Xenopus laevis. No N-terminal post-translational modification was found. The high number of substitutions in the sequence suggested that protein heterogeneity was a product of gene duplication. This was confirmed by isolation of two different cDNA clones. Nucleotide sequence analysis allowed the primary structure of the two peptide chains to be unambiguously assigned. The observed changes (19 in 150 residues) are distributed along the peptide chain to give similar protein net charges although substitutions of the same polarity and/or charge were the exception rather than the rule. The degree of diversity between the two Xenopus variants is comparable to that between mammalian sequences and shows that the putative increase of the rate of mutation for Cu,Zn superoxide dismutase at later evolution stages (Y. M. Lee et al., 1985, Arch. Biochem. Biophys. 241, 577-589; G. J. Steffens et al., 1986, Biol. Chem. Hoppe-Seyler 367, 1017-1024) is observed in amphibians. This is the first time complete sequences for Cu,Zn superoxide dismutase variants from the same organism have been found to be products of divergent genes and not simply allelic mutations.

Wheat germ cytoplasmic ribosomes. Structure of ribosomal subunits and localization of N6,N6-dimethyladenosine by immunoelectron microscopy.

Cytoplasmic ribosomes have been isolated from wheat germ, and the structure of ribosomal subunits has been examined by electron microscopy of negatively stained preparations. Small (40 S) subunits show structural features generally regarded as characteristic of eukaryotic particles, while large (60 S) subunits show shapes that are equally well described by models of prokaryotic 50 S particles. Small subunit 18 S RNA contains 2 residues of N6,N6-dimethyladenosine 19 and 20 residues from the 3'-end (Hagenbüchle, O., Santer, M., Steitz, J. A., and Mans, R. J. (1978) Cell 13, 551-563). Nucleoside analysis by high performance liquid chromatography shows no other residues of this component in the RNA. Anti-dimethyladenosine immunoglobulins were reacted with wheat germ 40 S subunits, and the resulting complexes were studied by electron microscopy in order to localize the nucleoside. In about 90% of the complexes observed, antibody-subunit contact was consistent with a single binding site. We place the dimethyladenosine residues at or near the end of the platform of the 40 S particle in a position nearly equivalent to that previously identified in prokaryotic and chloroplast subunits (Trempe, M. R., and Glitz, D. G. (1981) J. Biol. Chem. 256, 11873-11879).

Wheat germ cytoplasmic ribosomes. Localization of 7-methylguanosine and 6-methyladenosine by electron microscopy of immune complexes.

Nucleoside analysis of the RNA from the small subunit of wheat germ cytoplasmic ribosomes shows 1 mol each of N7-methylguanosine and N6-methyladenosine/mol of RNA. Antibodies directed against each methylated nucleoside were used to localize these residues within the subunit by electron microscopy of immune complexes. Antibodies to 7-methylguanosine bound 40 S subunits at a single site, at or slightly above the division between the upper and lower segments of the particle and on the surface furthest from the platform (or large lobe) of the subunit. This site is essentially equivalent to that previously seen with Escherichia coli and chloroplast 30 S subunits (Trempe, M. R., Ohgi, K., and Glitz, D. G. (1982) J. Biol. Chem. 257, 9822-9829). Antibodies to N6-monomethyladenosine were induced in rabbits with a nucleoside-albumin conjugate and shown to be specific for the modified nucleoside. Electron microscopy of antibody-subunit complexes placed the methyladenosine residue in a position that is essentially indistinguishable from that of 7-methylguanosine.

[Value of allergic intradermal reactions to antibiotics in preparation for surgery (in patients with a history of drug allergy)]. / Utilità delle intradermoreazioni allergologiche agli antibiotici nella preparazione ad interventi chirurgici (in pazienti con anamnesi farmaco-allergica).

An allergological examination technique for application in patients with a history of hypersensitivity to antibiotics is described with reference to a personal series of 250 subjects admitted to the Bologna University obstetric and gynaecological pathology department for small pelvis surgery. The method of investigation is described and the results obtained are reviewed. It is felt that the investigation is of value in preoperative screening insofar as it eliminates or reduces the risk of allergic shock, and enables more precisely directed antibiotic management to be employed.