Variation in SARS-CoV-2 bioaerosol production in exhaled breath

We developed a simple, non-invasive mask sampling method to quantify and sequence SARS-CoV-2 from exhaled breath. We found substantial variation between individuals in SARS-CoV-2 copies exhaled over a 15-minute period, which moderately correlated with nasal swab viral load. Talking was associated with a median of 2 log10 greater exhaled viral copies. Exposure varies substantially between individuals but may be risk stratified by nasal swab viral load and whether the exposure involved conversation.

Liberation of Serotonin Is Not Unaffected by Acetylcholine in Rat Hippocampus

Purpose: Raised cerebral titers of acetylcholine have notable links with storage symptomatology related to lower urinary tract symptoms. The hippocampus contributes to the normal control of continence in the majority of instances (circuit 3). Owing to synaptic connections with other nerve cells, acetylcholine affects the micturition pathway via the liberation of additional cerebral neurotransmitters. Despite the fact that cerebral serotonin is a key inhibitor of reflex bladder muscle contractions, the influence of acetylcholine on its liberation is poorly delineated. The current research was conducted in order to explore the role of acetylcholine in serotonin liberation from sections of rat hippocampus in order to improve the comprehension of the relationship between cholinergic and serotonergic neurons.Methods: Hippocampal sections from 6 mature male Sprague-Dawley rats were equilibrated over a 30-minute period in standard incubation medium so as to facilitate [3H]5-hydroxytryptamine (5-HT) uptake. The cerebral neurotransmitter, acetylcholine, was applied to the sections. Aliquots of drained medium solution were utilized in order to quantify the radioactivity associated with [3H]5-HT liberation; any alterations in this parameter were noted.Results: When judged against the controls, [3H]5-HT liberation from the hippocampal sections remained unaltered following the administration of acetylcholine, implying that this agent has no inhibitory action on this process.Conclusions: Serotonin liberation from murine hippocampal sections is unaffected by acetylcholine. It is postulated that the bladder micturition reflex responds to acetylcholine through its immediate cholinergic activity rather than by its influence on serotonin release. These pathways are a promising target for the design of de novo therapeutic agents.

Assessment of small-intestine permeability in healthy Nigerian children is altered by urinary volume and voiding status

Objective This study aimed to uncover the effect of voided urinary volume on small intestine permeability ratios in healthy children. Methods We assessed small intestine permeability in 155 apparently healthy children, aged 3–5 years old, without any visible symptoms of disease, in a rural, malaria-endemic setting in Nigeria, using a multi-sugar test solution, comprising lactulose, sucrose, mannitol, and rhamnose. Children were categorized into low urinary volume (LV) and high urinary volume (HV), based on the volume of urine voided per kg body weight per hour. LV children voided less than 25th percentile of the total population, while HV children voided greater than 75th percentile of the total population. Urinary volume excreted over a 90-minute period after administration of the test solution was measured, and differences in sugar ratios were compared between children with high (HV) and low urinary volumes (LV), as well as between children who voided (VC) or who were not able to void (NVC) before administration of the test solution. Results Urinary mannitol and rhamnose recovery were 44% (p = 0.002) and 77% (p<0.001) higher in HV children compared to LV children respectively, while urinary lactulose recovery was 34% lower (p = 0.071). There was no difference in urinary sucrose recovery between groups (p = 0.74). Lactulose-mannitol ratio, lactulose-rhamnose ratio and sucrose-rhamnose ratio were all significantly higher in children in the LV group compared to children in the HV group (p<0.001). In a multiple regression analysis, urinary volume and voiding status combined, explained 13%, 23% and 7% of the variation observed in lactulose-mannitol, lactulose-rhamnose and sucrose-rhamnose ratios, respectively. Conclusion Sugar permeability ratios vary significantly with total urinary volume in multi-sugar small-intestine permeability tests. Voiding status before sugar administration appears to influence lactulose recovery, lactulose-rhamnose and sucrose-rhamnose ratios independently of total urinary volume. Evidence from this study suggests the need to take urinary volume into account when conducting multi-sugar small-intestine permeability tests.

Abstract MP71: Impact Of 30 Versus 60 Second Time Interval Between Automated Office Blood Pressure Measurements On Measured Blood Pressure

Background: Guidelines advocate for the use of automated office-based blood pressure (AOBP) measurement to improve accuracy of blood pressure (BP) measurement in the outpatient clinical setting. Current recommendations include a 5-minute period of quiet rest prior to obtaining 3 readings, each separated by 1-2 minutes. As a result, AOBP requires a minimum of 7 minutes of rest time in addition to proper patient positioning plus cuff inflation and deflation, adding nearly 10 minutes to an office visit. Reducing this by even 1 minute has broad implications for the widespread use of AOBP. Methods: Patients from a single hypertension center underwent a 3-day evaluation that included a 24-hour ambulatory BP monitor (ABPM) and one of two, non-randomized, unattended AOBP protocols. Half of patients underwent 3 BP measurements separated by 30 seconds and the other half underwent 3 BP measurements separated by 60 seconds. All measurements were compared to the average awake-time BP from ABPM as well as the first AOBP measurement. Results: Among 102 patients, the average awake-time BP was 128.6±13.6/76.5±12.5 mmHg for the 30-second protocol and 132.5±15.6/77.7±12.2 mmHg among those who underwent the 60-second protocol . Mean BP was lower with the 2nd and 3rd AOBP measurement by -0.5/-1.7 mmHg and -1.0/-2.3 mmHg for the 60-second protocol versus -0.8/-2.0 mmHg and -0.7/-2.7 mmHg for the 30-second protocol ( Figure ). Differences between AOBP measurements (1st, 2nd, or 3rd) and awake-time ABPM were nearly identical across protocols. Conclusion: A 30-second interval between AOBP measurements was as accurate and reliable as a 60-second interval.

Efectos fisiológicos agudos de un dispositivo para ejercitarse en casa (Acute physiological response to exercising with a piece of home equipment )

A la luz de la importancia de la actividad física regular como un elemento clave en la prevención de muchas enfermedades, se reportan a continuación los resultados del estudio realizado con un aparato para ejercitarse en la casa. 22 estudiantes universitarios jóvenes, aparentemente saludables, participaron en el estudio. Se midió el efecto agudo de 10 minutos de ejercicio con el dispositivo sobre la frecuencia cardíaca, el costo energético y la circulación periférica en las piernas. Se contrastan los resultados obtenidos con las afirmaciones que se hacen en distintas versiones de publicidad del aparato en cuestión. No se obtuvieron efectos fisiológicos agudos significativos de la utilización del dispositivo durante 10 minutos continuos: la frecuencia cardíaca aumentó apenas 8 latidos por minuto con respecto al reposo y la temperatura cutánea no varió o más bien disminuyó. El costo energético no fue significativamente mayor mientras se usaba el dispositivo en comparación con la condición de reposo. Estos resultados sugieren que aquellas personas que utilicen este dispositivo en sustitución de la actividad física regular estarán sacrificando beneficios importantes para su salud. Abstract. The importance of doing regular physical activity (exercise) as a key element in the prevention of several diseases is well known. The following experiment was performed to evaluate the acute physiological effects of a home-exercise machine on 22 young, apparently healthy, university students. While the individuals exercised in the machine for ten (10) minutes, measures of heart rate, energy expenditure and peripheral circulation to the legs were taken and recorded. The results were contrasted against the claims made in different ads promoting the selected apparatus. There were no significant acute physiological effects resulting from the utilization of the machine during a 10-minute period. Heart rate increased only 8 beats per minute (bpm) from baseline and the temperature measured on the legs showed no variation or was even reduced. Energy expenditure was not significantly higher while using the device in comparison with the resting condition. These results suggest that consumers using this home-exercise equipment as a substitute of performing regular physical activity will be sacrificing important health benefits.

Variation in SARS-CoV-2 bioaerosol production in exhaled breath

Using face mask bioaerosol sampling, we found substantial variation between individuals in SARS-CoV-2 copies exhaled over a 15-minute period, which moderately correlated with nasal swab viral load. Talking was associated with a median of 2 log10 greater exhaled viral copies. Exposure varies substantially between individuals but may be risk stratified by nasal swab viral load and whether the exposure involved conversation.

Large variations of oxygen delivery in self-inflating resuscitation bags used for preoxygenation - a mechanical simulation

Background Self-Inflating Resuscitation Bags (SIRB) are common and essential tools in airway management and ventilation. They are often used in resuscitation and emergency anaesthesia outside the operating theatre. There is a common notion that all SIRBs applied with a tight sealed mask will deliver close to 100 % oxygen during spontaneous breathing. The aim of the study was to measure the oxygen delivery of six commonly used SIRBs in a mechanical spontaneous breathing adult in vitro model. Methods Three SIRBs of each of the six models were evaluated for oxygen delivery during simulated breathing with an adult mechanical lung. The test was repeated three times per device (54 tests in total). The breathing profile was fixed to a minute volume of 10 L/min, a tidal volume of 500 mL and the SIRBs supplied with an oxygen fresh gas flow of 15 L/min. The fraction of delivered oxygen (FDO2) was measured over a three-minute period. Average FDO2 was calculated and compared at 30, 60 and 90 s. Results At 90 s all models had reached a stable FDO2. Average FDO2 at 90 s; Ambu Oval Plus 99,5 %; Ambu Spur II 99,8 %; Intersurgical BVM Resuscitator 76,7 %; Laerdal Silicone 97,3 %; Laerdal The Bag II 94,5 % and the O-Two Smart Bag 39,0 %. All differences in FDO2 were significant apart from the two Ambu models. Conclusions In simulated spontaneous breathing, four out of six (by Ambu and Laerdal) Self-Inflating Resuscitation Bags delivered a high fraction of oxygen while two (Intersurgical and O-two) underperformed in oxygen delivery. These large variations confirm results reported in other studies. It is our opinion that underperforming Self-Inflating Resuscitation Bags might pose a serious threat to patients’ health if used in resuscitation and anaesthesia. Manufacturers of Self-Inflating Resuscitation Bags rarely provide information on performance for spontaneous breathing. This poses a challenge to all organizations that need their devices to deliver adequate oxygen during spontaneous breathing.

Recording Temporal Signals with Minutes Resolution Using Enzymatic DNA Synthesis

Employing DNA as a high-density data storage medium has paved the way for next-generation digital storage and biosensing technologies. However, the multipart architecture of current DNA-based recording techniques renders them inherently slow and incapable of recording fluctuating signals with sub-hour frequencies. To address this limitation, we developed a simplified system employing a single enzyme, terminal deoxynucleotidyl transferase (TdT), to transduce environmental signals into DNA. TdT adds nucleotides to the 3 prime ends of single-stranded DNA (ssDNA) in a template-independent manner, selecting bases according to inherent preferences and environmental conditions. By characterizing TdT nucleotide selectivity under different conditions, we show that TdT can encode various physiologically relevant signals like Co2+, Ca2+, Zn2+ concentrations and temperature changes in vitro. Further, by considering the average rate of nucleotide incorporation, we show that the resulting ssDNA functions as a molecular ticker tape. With this method we accurately encode a temporal record of fluctuations in Co2+ concentration to within 1 minute over a 60-minute period. Finally, we engineer TdT to allosterically turn off in the presence of physiologically relevant concentration of calcium. We use this engineered TdT in concert with a reference TdT to develop a two-polymerase system capable of recording a single step change in Ca2+ signal to within 1 minute over a 60-minute period. This work expands the repertoire of DNA-based recording techniques by developing a novel DNA synthesis-based system that can record temporal environmental signals into DNA with minutes resolution.

Anti-Convulsive Effect of Thiamine and Melatonin Combination in Mice; Involvement of Oxidative Stress

Background: Epilepsy, the second most frequent neurological disease, is a chronic disorder with a high lifetime prevalence. Therefore, various studies are needed to find new effective therapeutic agents to treat seizures or prevent its complications. In this study, we investigated the effects of thiamine, melatonin, and their combination on pentylenetetrazol (PTZ)-induced tonic-clonic seizures in mice. Methods: Male mice were randomly divided into six groups, including control, seizure control, diazepam, melatonin, thiamine, and melatonin and thiamine combination groups. Drugs were given orally in drinking water for 14 days. On the 15th day, the seizure was induced (except the control group) by intraperitoneal injection of PTZ. In all groups, the time between the injection the start of the seizure (latency) and the length of the seizure attack (duration) were measured in a 30-minute period. After measuring the latency and duration in all groups, mice were killed by CO2 Box, and their brains were dissected to be analyzed for malondialdehyde (MDA) level as a marker of oxidative stress. Results: The seizure duration was significantly lower in the groups of melatonin, thiamine, and thiamine and melatonin combination compared to the seizure control group. The latency times in these groups were significantly greater than the seizure control group. Moreover, MDA concentrations were lower in these groups compared to the seizure control group. Conclusion: Thiamine, melatonin and their combination can decrease the duration time of seizure and increase the latency period, which may result from inhibition of oxidative stress in the brain.

Mathematical Modeling of Brain Activity under Specific Auditory Stimulation

Understanding the connection between different stimuli and the brain response represents a complex research area. However, the use of mathematical models for this purpose is relatively unexplored. The present study investigates the effects of three different auditory stimuli on cerebral biopotentials by means of mathematical functions. The effects of acoustic stimuli (S1, S2, and S3) on cerebral activity were evaluated by electroencephalographic (EEG) recording on 21 subjects for 20 minutes of stimulation, with a 5-minute period of silence before and after stimulation. For the construction of the mathematical models used for the study of the EEG rhythms, we used the Box-Jenkins methodology. Characteristic mathematical models were obtained for the main frequency bands and were expressed by 2 constant functions, 8 first-degree functions, a second-degree function, a fourth-degree function, 6 recursive functions, and 4 periodic functions. The values obtained for the variance estimator are low, demonstrating that the obtained models are correct. The resulting mathematical models allow us to objectively compare the EEG response to the three stimuli, both between the stimuli itself and between each stimulus and the period before stimulation.