Potential Role of Porcine Reproductive and Respiratory Syndrome Virus Structural Protein GP2 in Apoptosis Inhibition

Porcine reproductive and respiratory syndrome virus (PRRSV) is a serious threat to the pork industry, and its pathogenesis needs further investigations. To study the role of two structural proteins of PRRSV in virus-host cells interactions, two stable cell lines (MARC-2a and MARC-N) expressing GP2 and N proteins, respectively, were established. We induced apoptosis in these cells by treating them with staurosporine and found a significant reduction in the number of apoptotic cells in MARC-2a as compared to MARC-N and MARC-145 cells. In addition, we found significantly higher activities of transcriptional factors (NF-B and AP-1) in both cell lines as compared to MARC-145 (parent cells). Overall, our data suggest that, although both stable cell lines activate NF-B and AP-1, GP2 triggers the antiapoptotic process through an intermediate step that needs to be further investigated

HIV-2 RNA dimerization is regulated by intramolecular interactions in vitro

Genomic RNA dimerization is an essential process in the retroviral replication cycle. In vitro, HIV-2 RNA dimerization is mediated at least in part by direct intermolecular interaction at stem–loop 1 (SL1) within the 5′-untranslated leader region (UTR). RNA dimerization is thought to be regulated via alternate presentation and sequestration of dimerization signals by intramolecular base-pairings. One of the proposed regulatory elements is a palindrome sequence (pal) located upstream of SL1. To investigate the role of pal in the regulation of HIV-2 dimerization, we randomized this motif and selected in vitro for dimerization-competent and dimerization-impaired RNAs. Energy minimization folding analysis of these isolated sequences suggests the involvement of pal region in several short-distance intramolecular interactions with other upstream and downstream regions of the UTR. Moreover, the consensus predicted folding patterns indicate the altered presentation of SL1 depending on the interactions of pal with other regions of RNA. The data suggest that pal can act as a positive or negative regulator of SL1-mediated dimerization and that the modulation of base-pairing arrangements that affect RNA dimerization could coordinate multiple signals located within the 5′-UTR

Randomization and In Vivo Selection Reveal a GGRG Motif Essential for Packaging Human Immunodeficiency Virus Type 2 RNA ▿ †

The packaging signal (ψ) of human immunodeficiency virus type 2 (HIV-2) is present in the 5′ noncoding region of RNA and contains a 10-nucleotide palindrome (pal; 5′-392-GGAGUGCUCC) located upstream of the dimerization signal stem-loop 1 (SL1). pal has been shown to be functionally important in vitro and in vivo. We previously showed that the 3′ side of pal (GCUCC-3′) is involved in base-pairing interactions with a sequence downstream of SL1 to make an extended SL1, which is important for replication in vivo and the regulation of dimerization in vitro. However, the role of the 5′ side of pal (5′-GGAGU) was less clear. Here, we characterized this role using an in vivo SELEX approach. We produced a population of HIV-2 DNA genomes with random sequences within the 5′ side of pal and transfected these into COS-7 cells. Viruses from COS-7 cells were used to infect C8166 permissive cells. After several weeks of serial passage in C8166 cells, surviving viruses were sequenced. On the 5′ side of pal there was a striking convergence toward a GGRGN consensus sequence. Individual clones with consensus and nonconsensus sequences were tested in infectivity and packaging assays. Analysis of individuals that diverged from the consensus sequence showed normal viral RNA and protein synthesis but had replication defects and impaired RNA packaging. These findings clearly indicate that the GGRG motif is essential for viral replication and genomic RNA packaging

Neonatal Botulism: A Case Series Suggesting Varied Presentations

Infantile botulism is an uncommon diagnosis and rarer still in the neonatal period. We describe three cases of neonatal-onset botulism that presented with symptoms typically (hypotonia, constipation, facial diplegia) or atypically seen in older infants (encephalopathy, seizures, and hypothermia). Our series shows a wider spectrum of clinical presentations in patients with neonatal-onset botulism. Our report also suggests that neonatal-onset botulism should be considered more broadly in the hypotonic infant, especially as the condition is treatable with intravenous botulinum-specific immune globulin

Focal to bilateral tonic-clonic seizures predict pharmacoresistance in focal cortical dysplasia-related epilepsy

OBJECTIVE: Focal cortical dysplasia (FCD) is the most common etiology of surgically-remediable epilepsy in children. Eighty-seven percent of patients with FCD develop epilepsy (75% is pharmacoresistant epilepsy [PRE]). Focal to bilateral tonic-clonic (FTBTC) seizures are associated with worse surgical outcomes. We hypothesized that children with FCD-related epilepsy with FTBTC seizures are more likely to develop PRE due to lesion interaction with restricted cortical neural networks. METHODS: Patients were selected retrospectively from radiology and surgical databases from Children\u27s National Hospital. INCLUSION CRITERIA: 3T magnetic resonance imaging (MRI)-confirmed FCD from January 2011 to January 2020; ages 0 days to 22 years at MRI; and 18 months of documented follow-up. FCD dominant network (Yeo 7-network parcellation) was determined. Association of FTBTC seizures with epilepsy severity, surgical outcome, and dominant network was tested. Binomial regression was used to evaluate predictors (FTBTC seizures, age at seizure onset, pathology, hemisphere, lobe) of pharmacoresistance and Engel outcome. Regression was used to evaluate predictors (age at seizure onset, pathology, lobe, percentage default mode network [DMN] overlap) of FTBTC seizures. RESULTS: One hundred seventeen patients had a median age at seizure onset of 3.00 years (interquartile range [IQR] .42-5.59 years). Eighty-three patients had PRE (71%); 34 had pharmacosensitive epilepsy (PSE) (29%). Twenty patients (17%) had FTBTC seizures. Seventy-three patients underwent epilepsy surgery. Multivariate regression showed that FTBTC seizures are associated with an increased risk of PRE (odds ratio [OR] 6.41, 95% confidence interval [CI] 1.21-33.98, p = .02). FCD hemisphere/lobe was not associated with PRE. Percentage DMN overlap predicts FTBTC seizures. Seventy-two percent (n = 52) overall and 53% (n = 9) of patients with FTBTC seizures achieved Engel class I outcome. SIGNIFICANCE: In a heterogeneous population of surgical and non-operated patients with FCD-related epilepsy, the presence of FTBTC seizures is associated with a tremendous risk of PRE. This finding is a recognizable marker to help neurologists identify those children with FCD-related epilepsy at high risk of PRE and can flag patients for earlier consideration of potentially curative surgery. The FCD-dominant network also contributes to FTBTC seizure clinical expression

Lower or Higher Oxygenation Targets for Acute Hypoxemic Respiratory Failure.

BACKGROUND Patients with acute hypoxemic respiratory failure in the intensive care unit (ICU) are treated with supplemental oxygen, but the benefits and harms of different oxygenation targets are unclear. We hypothesized that using a lower target for partial pressure of arterial oxygen (Pao2) would result in lower mortality than using a higher target. METHODS In this multicenter trial, we randomly assigned 2928 adult patients who had recently been admitted to the ICU (≤12 hours before randomization) and who were receiving at least 10 liters of oxygen per minute in an open system or had a fraction of inspired oxygen of at least 0.50 in a closed system to receive oxygen therapy targeting a Pao2 of either 60 mm Hg (lower-oxygenation group) or 90 mm Hg (higher-oxygenation group) for a maximum of 90 days. The primary outcome was death within 90 days. RESULTS At 90 days, 618 of 1441 patients (42.9%) in the lower-oxygenation group and 613 of 1447 patients (42.4%) in the higher-oxygenation group had died (adjusted risk ratio, 1.02; 95% confidence interval, 0.94 to 1.11; P = 0.64). At 90 days, there was no significant between-group difference in the percentage of days that patients were alive without life support or in the percentage of days they were alive after hospital discharge. The percentages of patients who had new episodes of shock, myocardial ischemia, ischemic stroke, or intestinal ischemia were similar in the two groups (P = 0.24). CONCLUSIONS Among adult patients with acute hypoxemic respiratory failure in the ICU, a lower oxygenation target did not result in lower mortality than a higher target at 90 days. (Funded by the Innovation Fund Denmark and others; HOT-ICU ClinicalTrials.gov number, NCT03174002.)