Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

Studies on the effect of polyvinyl pyrrolidone on the activity of chlorhexidine mouthrinses: plaque and stain

Background, aims: Polyvinyl pyrrolidone (PVP) was shown in vitro to reduce chlorhexidine induced, dietary staining without affecting the uptake of the antiseptic to the test substrate. The aim of these studies in vivo was to determine whether PVP affected plaque and dietary staining by a low concentration chlorhexidine rinse. Methods: The plaque and stain studies used a double blind, randomised 6, treatment crossover design involving healthy subjects with a high standard of oral hygiene and gingival health. The rinse formulations under test were: (A) aqueous alcohol (placebo control), (B) 0.03% chlorhexidine, (C) 0.06% chlorhexidine, (D) 0.06% chlorhexidine+1.2% PVP, (E) 0.06% chlorhexidine+5% PVP, (F) 0.06% chlorhexidine+10% PVP. In the plaque study, on day 1 of each period, subjects were rendered plaque free and then rinsed with 15 ml of the test rinse for 60 s. No further tooth cleaning was performed and subjects returned 24 h later for plaque scoring by area. In the stain study, on day 1 of each period, the tongue and teeth of each subject were rendered stain free. Subjects then rinsed under supervision for 60 s with 15 ml of the allocated rinse 8× a day between 09:00 h and 17:00 h for 3 days. Immediately after each rinse with the test formulation, subjects rinsed for 120 s with 15 ml of warm black tea. Subjects were requested to also drink at least 5 cups of tea or coffee per day. On day 4, stain was scored by area and intensity from designated teeth and dorsum of the tongue. Washout periods were at least 7 days in both studies. Results: Plaque areas were greatest with placebo and least with 0.06% chlorhexidine. Plaque scores increased with increasing concentrations of PVP in the 0.06% chlorhexidine rinse and were significantly higher than 0.06% chlorhexidine without PVP rinse. Tooth stain areas were comparable for placebo, 0.03% and 0.06% chlorhexidine rinses, but significantly reduced with the PVP/chlorhexidine rinses compared to the 0.06% chlorhexidine rinse. Tooth stain intensity was significantly increased with 0.06% chlorhexidine rinses compared to placebo and chlorhexidine/PVP rinses. Tongue stain area and intensity were significantly reduced with 5% and 10% PVP/chlorhexidine rinses compared to 0.06% chlorhexidine rinse. Conclusion: PVP, at the concentrations tested, reduced the stain propensity of a 0.06% chlorhexidine rinse but at the expense of some loss of plaque inhibition

Conversion of plaque-area measurements to plaque index scores: an assessment of variation and discriminatory power

Plaque areas recorded graphically or photographically provide a permanent record of plaque accumulations on teeth at a moment in time. As such, these records could be re‐evaluated and converted into other index scores. The purpose of this study was to determine the reproducibility of scoring a plaque index from previously recorded plaque areas and to compare such scores with the original scores of the same index. A randomised blind, crossover study comparing 5 treatments for plaque inhibition scored by plaque area and index was chosen. 2 examiners, the original scorer PRH and another, NC, 2× scored the plaque area tooth charts according to the criteria of the plaque index system used in the original study. Standard deviations of the differences showed intraexaminer repeatability to be high particularly for the original examiner. Interexaminer reproducibility for the original index scores was considered good but less than for intra‐examiner repeatability. Correlation coefficients were complimentary to the differences analysis, being very high within examiners and less high for between examiners and original and rescored index. Separation between distributions of plaque area measurements for consecutive values of the index were particular good for scores 2 versus 3 and 3 versus 4 and less good for 1 versus 2 and 4 versus 5. Reanalysis of the study for treatment differences using rescored data revealed a similar level of significance as using the original data. Rescored index had similar discriminatory power for the study as plaque area and original plaque index when both were derived from the same buccal tooth surfaces. However, discriminatory power was less by comparison with original plaque index derived from the buccal surfaces of all teeth. It is concluded that plaque area provides a permanent record of plaque distribution which can be converted into index data at a later date. Such data collection could make possible comparisons between studies using different indices

Clinical development and evolution in plaque removal performance of a battery powered toothbrush

Background and aim: There is growing evidence that the new generation of electric toothbrushes are more effective than manual toothbrushes. The primary aim of these studies was to compare, as an indication of the stage of development, the plaque removal properties of a prototype battery powered toothbrush with an established product. A secondary aim was to utilise the data to appraise plaque accumulation together with the patterns of removal. Method: The three studies presented used the same, single‐examiner, randomised, single‐blind cross‐over design involving up to 24 healthy volunteers. The prototype brushes, E6500 versions s1, s2 and s3 and E8000 with head speeds of 6500 and 8000 oscillations/min were compared with a similar design marketed product (MP) with a head speed of 8800 oscillations/min. All brushes had circular brush heads with oscillating rotating actions. Subjects accumulated plaque over a 4‐day period during which no oral hygiene measures were performed. On day 4, the plaque accumulation was scored by index. Subjects then used the allocated toothbrush for 2 min. This was followed by a re‐scoring of the remaining plaque. Results: Studies 1 and 2 showed significantly less plaque removed by prototype E6500 (s1) and prototype E6500 (s2), respectively, than by MP. In study 3, prototype E8000 removed similar quantities of plaque to MP (approximately 65%). In contrast prototype E6500 (s3) only removed 60% of accrued plaque. Differences, however, did not reach statistical significance. Conclusions: The study methodology was appropriate to distinguish between the study toothbrushes and was furthermore able to establish a level of comparability for one of the prototype modifications with a similar MP