COVID-19 vaccine safety in Scotland - background rates of adverse events of special interest.

OBJECTIVES: Mass COVID-19 vaccination commenced in December 2020 in Scotland. Monitoring vaccine safety relies on accurate background incidence rates (IRs) for health outcomes potentially associated with vaccination. This study aimed to quantify IRs in Scotland of adverse events of special interest (AESI) potentially associated with COVID-19 vaccination. STUDY DESIGN AND METHODS: IRs and 95% confidence intervals (CIs) for 36 AESI were calculated retrospectively for the pre-COVID-19 pandemic period (01 January 2015-31 December 2019) and the COVID-19 pandemic period (01 April 2020-30 November 2020), with age-sex stratification, and separately by calendar month and year. Incident cases were determined using International Classification of Diseases-10th Revision (ICD-10)-coded hospitalisations. RESULTS: Prepandemic population-wide IRs ranged from 0.4 (0.3-0.5 CIs) cases per 100,000 person-years (PYRS) for neuromyelitis optica to 478.4 (475.8-481.0 CIs) cases per 100,000 PYRS for acute renal failure. Pandemic population-wide IRs ranged from 0.3 (0.2-0.5 CIs) cases per 100,000 PYRS for Kawasaki disease to 483.4 (473.2-493.7 CIs) cases per 100,000 PYRS for acute coronary syndrome. All AESI IRs varied by age and sex. Ten AESI (acute coronary syndrome, acute myocardial infarction, angina pectoris, heart failure, multiple sclerosis, polyneuropathies and peripheral neuropathies, respiratory failure, rheumatoid arthritis and polyarthritis, seizures and vasculitis) had lower pandemic than prepandemic period IRs overall. Only deep vein thrombosis and pulmonary embolism had a higher pandemic IR. CONCLUSION: Lower pandemic IRs likely resulted from reduced health-seeking behaviours and healthcare provision. Higher IRs may be associated with SARS-CoV-2 infections. AESI IRs will facilitate future vaccine safety studies in Scotland.

A G protein-coupled receptor for UDP-glucose.

Uridine 5'-diphosphoglucose (UDP-glucose) has a well established biochemical role as a glycosyl donor in the enzymatic biosynthesis of carbohydrates. It is less well known that UDP-glucose may possess pharmacological activity, suggesting that a receptor for this molecule may exist. Here, we show that UDP-glucose, and some closely related molecules, potently activate the orphan G protein-coupled receptor KIAA0001 heterologously expressed in yeast or mammalian cells. Nucleotides known to activate P2Y receptors were inactive, indicating the distinctly novel pharmacology of this receptor. The receptor is expressed in a wide variety of human tissues, including many regions of the brain. These data suggest that some sugar-nucleotides may serve important physiological roles as extracellular signaling molecules in addition to their familiar role in intermediary metabolism.

Characterization of two types of termination signal for bacteriophage T7 RNA polymerase.

The late bacteriophage T7 terminator (T7-T phi) encodes an RNA sequence that can form a stable stem-loop structure followed by a run of six uridylate residues; termination occurs at a 3' G residue just downstream of the U run. In this work, we have explored the features of this signal that are required for efficient termination by T7 RNA polymerase. Whereas replacement of the template-encoded 3' G residue with A, C, or U by site-directed mutagenesis had little effect, removal of the U-tract prevented termination. Deletion analysis indicates that the stem-loop and U-tract are not sufficient for termination, and that sequences upstream from the terminator have marked effects on the position and efficiency of termination. A sequence within the human preproparathyroid hormone (PTH) gene that encodes an interrupted run of six U residues, but lacks an apparent stem-loop structure, also serves as an efficient terminator for T7 RNA polymerase. We have mapped the primary site of termination in the PTH signal to a G residue that lies downstream of the U-rich run (UUUUCUUG). Deletion analysis indicates that the minimal region required for PTH terminator function extends only 23 bp upstream from the termination site, and subcloning of a 31 bp fragment that includes this region of the PTH signal provides efficient termination. A modified form of T7 RNA polymerase resulting from a single proteolytic cleavage between residues 178 and 179, or mutant polymerases that are altered in this region of the enzyme, fail to recognize the PTH signal while still terminating at T7-T phi.

Termination and slippage by bacteriophage T7 RNA polymerase.

We have examined the termination efficiency of T7 and T3 RNA polymerases (RNAPs) at a variety of termination signals. In agreement with previous investigators we find that termination occurs after the synthesis of an RNA product with a stable secondary structure followed by a run of U residues. Stem-loop structures that lack a 3' U-tract fail to terminate the phage enzyme. The distance (or the sequence) between the start site for transcription and the termination signal may also be important, as placing the terminator at different locations downstream from the promoter, or changing the promoter sequence, results in alterations in termination efficiency. We have explored termination at extended runs of homopolymers in the absence of an apparent stem-loop structure, and have observed that the enzyme terminates (inefficiently) when synthesizing U-rich transcripts, but not A- or C-rich transcripts. This is especially true at low concentrations of UTP. Strikingly, when an elongation complex (EC) encounters a dA-tract in the template strand it is able to slide on the template, resulting in the synthesis of products that have more or fewer U residues than predicted by the sequence of the DNA. This observation suggests that the formation of an RNA: DNA hybrid may be important to the lateral stability of the EC (its ability to maintain proper register with the DNA template). We have also explored the termination properties of a proteolytically nicked form of T7 RNAP. The nicked enzyme forms a less stable EC than the intact RNAP and dissociates more readily from the template in regions that encode inherently destabilizing RNAs (e.g. stem-loop structures, poly(U)-tracts). However, the nicked enzyme terminates less efficiently at the late T7 terminator (T7-T phi) or at a termination signal in the human preproparathyroid hormone gene. These results suggest that termination is a highly specific event, and not merely a consequence of decreased stability of the EC. Our observations are not consistent with previous models of termination by the phage RNAP and indicate that revisions to these models may be required.

Pasteurella haemolytica is highly sensitive to ultraviolet irradiation.

The response of Pasteurella haemolytica to ultraviolet irradiation was determined. The results for survival show that P. haemolytica is very sensitive to UV-irradiation. This UV-sensitivity is similar to E. coli strains defective in UV repair mechanism(s). Analysis of the distribution of TCA insoluble versus TCA soluble [3H]thymine dimers in UV-irradiated DNA of P. haemolytica during a 2-h post-irradiation period indicates that the bacterium is deficient in an excision-repair system. These data suggest that P. haemolytica lacks some of the important mechanisms to repair UV-induced damage.