Noradrenaline synthesis and utilization: Control by nerve impulse flow under normal conditions and after treatment with alpha-adrenoreceptor blocking agents

The changes in the synthesis and utilization or noradrenaline cranial and caudal to an acute section of the rat spinal cord have been used to investigate the importance of nerve impulses for these processes. 1. Cranial to a lesion of the spinal cord, the alpha-methyltyrosine-induced disappearance of noradrenaline was accelerated by the alpha-adrenoreceptor blocking agents yohimbine (10 mg/kg), piperoxan (60 mg/kg) and tolazoline (50 mg/kg). In the absence of nerve impulses caudal to a lesion of the spinal cord, this disappearance was decelerated as compared to that cranial to the lesion and it was not influenced by the three alpha-adrenoreceptor blocking agents. 2. The nialamide-induced accumulation of normetanephrine in the whole brain was increased by phenoxybenzamine (20 mg/kg) and yohimbine whereas it was decreased by the alpha-adrenoreceptor stimulating agent clonidine (0.1 mg/kg). The effect of clonidine was completely antagonized by yohimbine, but not by phenoxybenzamine, giving further evidence for the view that clonidine and yohimbine have a stronger effect than phenoxybenzamine on the alpha-adrenoreceptors regulating the release of noradrenaline induced by nerve impluses. 3. The accumulation of Dopa after decarboxylase inhibition cranial to a lesion of the spinal cord was accelerated by yohimbine, piperoxan and tolazoline, but not significantly affected by phenoxybenzamine and haloperidol (10 mg/kg). In the absence of nerve impulses caudal to a lesion of the spinal cord, the popa accumulation was decelerated as compared to that cranial to the lesion and it was not influenced by the former three alpha--adrenoreceptor blocking agents as well as by clonidine. 4. The results show that the synthesis and the utilization noradrenaline normally, as well as the accelerations of these processes by alpha-adrenoreceptor blocking agents, are dependent on nerve impulses. The stimulation of the synthesis and utilization of noradrenaline by nerve impulses might by influenced via the activity of teh alpha-adrenoreceptors located either on the nerve terminals or on the cell bodies or on both parts of the noradrenergic neurones. In the absence of nerve impulses, a receptor-mediated feedback mechanism similar to that described for the synthesis of dopamine does not appear to regulate the synthesis of noradrenaline.     

Evidence for the involvement of the ventro-medial prefrontal cortex in a short-term storage of visual images

The purpose of this study was to clarify the role of the ventro-medial prefrontal cortex in short-term visual memory. Patients with focal lesions to the right gyrus rectus were impaired on a size judgement task, which required short-term retention of laterally presented visual patterns. The impairment was most evident when the stimuli were addressed to the damaged hemisphere (left visual field presentations) and when separated by very short (50-500 ms) intervals. The findings suggest that the ventro-medial part of the orbitofrontal cortex, like the ventro-lateral part, is involved in short-term storage of icon-like representations of visual objects, and also that there exists a right-hemispheric specialization for that function. Our study presents the first direct evidence of such specific memory effects in humans using a lesion method and points to the importance of the right gyrus rectus area in maintaining the representation of stimuli after they are removed from view.     

Red blood cells deformability and oxidative stress in acute pancreatitis

The aim of this study was to evaluate the RBC deformability and oxidative stress parameters during acute pancreatitis. Healthy volunteers and patients with mild or severe acute pancreatitis were evaluated. There were no changes in erythrocyte's deformability in patients with mild acute pancreatitis. In severe acute pancreatitis loss of deformability of erythrocytes was observed. Serum lipofuscin level increased both in mild and severe form of the disease. The superoxide dismutase (SOD) activity was increased in erythrocytes from mild and severe form without systemic complications and was positively correlated with erythrocyte's deformability in a severe form of acute pancreatitis. Significant positive correlation between serum total antioxidant status and deformability of erythrocytes in healthy humans and negative correlation in mild pancreatitis were found.     

Catalytic and photocatalytic oxidation of diphenyl sulphide to diphenyl sulfoxide over titanium dioxide doped with vanadium,zinc, and tin

Samples of TiO₂ (P25) doped with zinc, tin, and vanadium, thermally treated at 550 °C for 6 h, were tested as catalysts and photocatalysts for the oxidation of diphenyl sulphide to diphenyl sulfoxide and sulfone, using hydrogen peroxide as an oxidation agent. Thermal treatment of pure TiO₂ and its vanadium-doped forms resulted in a decrease of anatase and an increase of rutile content. The opposite effect was observed for TiO₂ doped with zinc or tin, where thermal treatment resulted in the rutile to anatase phase transition. The role of V, Zn, and Sn admixtures as TiO₂ phase-composition controllers was postulated. The catalytic and photocatalytic activity was found to be influenced more by the rutile and anatase contents of the samples than the presence of admixtures. The rutile-containing samples, TiO₂ and V-TiO₂, presented much better activity in the catalytic oxidation of diphenyl sulphide compared with the catalysts that only contained the anatase phase, Sn-TiO₂ and Zn-TiO₂. The reaction efficiency was significantly improved under UV radiation. In this case, the best photocatalytic activity was found for calcined TiO₂, containing both anatase and rutile components. An increase in rutile content, observed in the vanadium-doped TiO₂, decreased the efficiency of the photocatalytic diphenyl sulphide oxidation. Thus, the presence of both anatase and rutile phases, with their favourable contributions, typical for P25, is necessary for the effective oxidation of Ph₂S to Ph₂SO. Moreover, it was shown that for the second oxidation stage, Ph₂SO to Ph₂SO₂, the presence of the rutile phase is very important.

Phase transitions of rutile and anatase were directed by V, Zn and Sn admixtures. Rutile containing catalysts were more active in Ph₂S oxidation than pure anatase samples. Efficiency of Ph₂S oxidation was significantly improved under UV radiation.     

Cumulative Effects of Particulate Matter Pollution and Meteorological Variables on the Risk of Influenza-Like Illness

The cold season is usually accompanied by an increased incidence of respiratory infections and increased air pollution from combustion sources. As we are facing growing numbers of COVID-19 cases caused by the novel SARS-CoV-2 coronavirus, an understanding of the impact of air pollutants and meteorological variables on the incidence of respiratory infections is crucial. The incidence of influenza-like illness (ILI) can be used as a close proxy for the circulation of influenza viruses. Recently, SARS-CoV-2 has also been detected in patients with ILI. Using distributed lag nonlinear models, we analyzed the association between ILI, meteorological variables and particulate matter concentration in Bialystok, Poland, from 2013–2019. We found an exponential relationship between cumulative PM_2.5 pollution and the incidence of ILI, which remained significant after adjusting for air temperatures and a long-term trend. Pollution had the greatest effect during the same week, but the risk of ILI was increased for the four following weeks. The risk of ILI was also increased by low air temperatures, low absolute humidity, and high wind speed. Altogether, our results show that all measures implemented to decrease PM_2.5 concentrations would be beneficial to reduce the transmission of SARS-CoV-2 and other respiratory infections.