A two diffusion stochastic model for the spread of the new corona virus SARS-CoV-2.

We propose a refined version of the stochastic SEIR model for epidemic of the new corona virus SARS-Cov-2, causing the COVID-19 disease, taking into account the spread of the virus due to the regular infected individuals (transmission coefficient ß ), hospitalized individuals (transmission coefficient l ß , l > 0 ) and superspreaders (transmission coefficient ß ' ). The model is constructed from the corresponding ordinary differential model by introducing two independent environmental white noises in transmission coefficients for above mentioned classes - one noise for infected and hospitalized individuals and the other for superspreaders. Therefore, the model is defined as a system of stochastic differential equations driven by two independent standard Brownian motions. Existence and uniqueness of the global positive solution is proven, and conditions under which extinction and persistence in mean hold are given. The theoretical results are illustrated via numerical simulations.

Links between conspiracy beliefs, vaccine knowledge, and trust: Anti-vaccine behavior of Serbian adults.

RATIONALE: Immunization is a critical tool in the fight against infectious disease epidemics. Understanding hesitancy towards immunization is even more important nowadays, with the continuous threat of COVID-19 pandemic. Medical conspiracy beliefs, scientific skepticism, as well as low trust in governmental institutions, and evidence-based knowledge all have troubling effects on immunization. OBJECTIVE: To examine how these factors cross-react to influence vaccine behavior against any vaccine preventable disease (VPD), we hypothesized a model consisting of the belief in conspiracy theories as the predictor, and as the mediators subjective and objective vaccine knowledge, and trust in the health care system and science. The model was tested by examining the vaccine intentions for the children and self for any VPD. METHODS: Two separate studies were conducted on the representative samples of Serbian population; the first study investigated the intentions for child vaccination and the second study examined the vaccine intentions against any VPD, including adult vaccination. We used path analysis followed by logistic regression to analyze the data. RESULTS: The results revealed high vaccine hesitancy motivated by the belief in the vaccine conspiracy theories, through its effect on reduced trust in medical science and institutions, and low objective vaccine knowledge. CONCLUSIONS: The results of this study may be used to implement appropriate policy changes and implementation of the public health campaigns to promote immunization with a wide range of vaccines against common diseases, such as measles, human papillomaviruses, or pertussis, and novel diseases, such as COVID.

The importance of antioxidant enzyme and total antioxidant status of patients with acute myocardial infarction on thrombolytic therapy.

It is believed that intensive production of free radicals occurs immediately after reperfusion, and that it explains a series of adverse effects of reperfusion. The aim of the study was to establish the importance of the antioxidative enzymes superoxide dismutase (SOD), glutathione peroxidase (GPX) and the total antioxidant status (TAS) in patients with acute myocardial infarction according to success or failure of reperfusion. Enzyme activities in erythrocyte hemolysate and concentration of TAS in plasma were determined by Randox kits in 50 patients with acute myocardial infarction. No significant differences in TAS between the mean values against either clinical status or the 10 time intervals were recorded. The SOD and GPX values were significantly influenced by the presence or absence of reperfusion (p<0.05). Monitoring of SOD and GPX at ten time points: before administration of streptokinase, 1, 3, 6, 12, 18, 24 hours, 2, 3 and 5 days after administration of streptokinase revealed the lowest SOD levels up to one hour before administration of streptokinase, supporting the fact that the maximum production of free radicals is achieved at that time. GPX values differed for 24 hours according to whether reperfusion was achieved or not. The obtained results suggest that free radical production is increased after reperfusion, and monitoring of antioxidant enzymes may help to evaluate the success of thrombolytic therapy.

Endogenous nucleosides in the guinea-pig eye: analysis of transport and metabolites.

This study investigates the transport of endogenous nucleosides and deoxynucleosides from the capillaries of the eye into the aqueous humour and the lens using the in situ vascular eye perfusion technique in the guinea-pig. The transport of [3H] adenosine and [3H] thymidine across the blood-aqueous barrier proved to be very rapid with a volume of distribution after 4 minutes perfusion reaching 11.9+/-3.0% and 9.93+/-1.1%, respectively. However, the transport of [3H] guanosine and [3H] cytidine was slower, with volumes of distribution reaching only 3.38+/-0.58% and 4.8+/-1.41%. The values for the entry of deoxyadenosine and deoxyguanosine were not significantly different from the values obtained for corresponding ribonucleosides (adenosine and guanosine) so that a change in the pentose sugar does not change the affinity of the nucleoside for the transport protein. Perfusion with a low sodium medium inhibited the transport of [3H] adenosine and [3H] thymidine into the aqueous humour. The presence of 800 nM NBTI also caused a decrease in adenosine transport into the aqueous humour, so that the volume of distribution after 2 minutes reached only 3.78+/-1.87%. These findings suggest that the transfer of adenosine across the blood-aqueous barrier has both concentrative and equilibrative components. The presence of 0.1 mM thymidine had no effect on the [3H] adenosine transport, whereas 0.1 mM of adenosine resulted in a marked decrease on the [3H] thymidine transport which suggests that the concentrative nucleotide transport is probably mediated by both cif and cit transport systems. The cellular uptake of nucleosides into the lens was very rapid and the volume of distribution of purine nucleosides was within the range of 30-50% whereas that for thymidine uptake was somewhat lower, reaching 20-30%. HPLC analysis of the eye structures in the guinea-pig showed that lens, vitreous body and the rest of the eye do not contain either free nucleosides or purine bases in detectable quantities, except for xanthine which was detected in aqueous humour at a concentration of 2.51+/-0.51 mM. However, serum of the anaesthetised guinea-pig did not contain xanthine in detectable amount so it seems that the metabolic degradation of the nucleosides in the guinea-pig eye progresses as far as xanthine, which is then accumulated in the aqueous humour.

Safety and effectiveness of leflunomide in the treatment of patients with active rheumatoid arthritis. Results of a randomized, placebo-controlled, phase II study.

OBJECTIVE: To assess the safety and effectiveness of leflunomide versus placebo in patients with active rheumatoid arthritis (RA) treated for 6 months. METHODS: Four hundred two patients were randomly assigned to receive placebo or leflunomide at 5 mg, 10 mg, or 25 mg daily. A washout period of 6-12 weeks from prior second-line therapy was required. RESULTS: Statistically significant improvement in primary and secondary outcome measures, as well as by responder analyses, occurred in the 10-mg and 25-mg dosage groups compared to placebo. Twenty-one patients (7.0%) in the active treatment groups withdrew due to adverse events (AEs). The incidence of AEs was higher with leflunomide than with placebo. Gastrointestinal symptoms, weight loss, allergic reactions, skin rash, and reversible alopecia were more common in the 10-mg and 25-mg dosage groups. The incidence of infections was similar between the treatment and placebo groups; no opportunistic infections were seen. Transient elevations in liver function studies were noted in a small number of patients. CONCLUSION: Leflunomide is effective in daily doses of 10 mg and 25 mg in patients with active RA. Improved efficacy at the 25-mg dose was associated with a higher incidence of AEs. Randomized, placebo-controlled trials using daily doses of 10 mg and 20 mg are under way in the US and Europe to confirm these positive results.

Influence of various cholinergic and anticholinergic drugs on rectal temperature in rats.

The influence of various cholinergic drugs on rectal temperature of rats under controlled laboratory conditions was examined. Animals were anaesthetized by intraperitoneal injection of thiopental. Three hours later acetylcholine, methacholine, arecoline, nicotine, neostigmine, atropine, methylatropine, mecamylamine or hemicholinium were injected intrahypothalamically (i.h.), intracerebroventricularly (i.c.v.) or intraperitoneally (i.p.). Rectal temperature was measured at 15 min-intervals for 1 hr after the substances were injected. Our results indicate that the cholinergic mechanisms play an important role in thermoregulatory processes in rats. Cholinergic activation decreases rectal temperature, due to an increased activity of central, and not of peripheral cholinergic neurotransmission. The hypothermic effect of cholinomimetics is mediated through an activation of muscarinic cholinergic receptors.