Development and study of the stability of comenic acid solutions

Introduction. The article presents the development of solutions based on the comenic acid substance. The criteria of the studied compositions that affect their stability during storage are evaluated within the framework of the Quality-by-Design concept. The optimal compositions of comenic acid solutions have been established.Aim. The purpose of the study is to develop solutions based on the comenic acid substance and determine the most stable variants of execution.Materials and methods. The study of comenic acid solutions was carried out by using a laboratory pH meter PB-11-P11 (SARTORIUS, Germany) and a liquid/ion chromatograph "Stayer" ("Akvilon" JSC, Russia).Results and discussion. The study made it possible to determine the most stable compositions of solutions based on the comenic acid substance and to establish optimal indicators of their stability criteria. It was found that solutions of comenic acid are the most stable in the pH range: from 4.0 to 6.0. At the same time, regardless of the studied methods of neutralization of comenic acid, solutions are unstable at concentrations of 25 mg/ml or more.Conclusion. As a result of the study, the optimal compositions of solutions based on the comenic acid substance were determined. A comparative analysis of excipients that increase the solubility of comenic acid in aqueous solvents is performed. The stability criteria of the studied solutions are established and their values for ensuring the stability of the developed drug are determined.

Comorbid insomnia and arterial hypertension: pathogenetic models and promising biomarkers

The review describes the major mechanisms for the initiation and maintenance of comorbid insomnia and arterial hypertension based on the relevant pathogenetic scenarios of insomnia such as the concept of sympathetic activation, the neurobiological model of insomnia, and stress-diathesis model (or 3-P model). The clinical data are lacking, and available clinical studies indicate the association between blood pressure levels and the hyperactivation of the central nervous system during sleep, characterized by electroencephalographic β-activity, and with sleep latency. However, biologically active substances involved in “neurogenic inflammation” also play a significant role in homeostasis maintenance following the exposure to endogenous and exogenous stress factors. The functions of interleukin-6, gamma-aminobutyric acid, substance P, melatonin, serotonin and orexin in normal and pathological conditions indicate their contribution to the development of comorbid insomnia and hypertension. We emphasize the role of insomnia as a separate nosological unit, comorbid with hypertension, as well as the importance of research of molecular mechanisms underlying the association between insomnia and arterial hypertension aimed at identification of therapeutic targets and prognostic markers.

The Activity of Oxidative Stress Markers in Acute Respiratory Distress Syndrome / Oksidativa Stresa Marķieru Aktivitate Akuta Respiratora Distresa Sindroma Gadījuma

Acute respiratory distress syndrome is a common complication characterised by severe hypoxemia, which leads to high mortality rates in ICU patients. Imbalance between oxidative stress markers like oxidants and antioxidants may play an important role in pathophysiology of the syndrome. We observed 17 ARDS patients during seven days after inclusion, with the main goal to describe dynamic changes in the level of oxidative stress markers in patients with acute respiratory distress syndrome. We found that there are dynamic differences in the level of malondialdechyde (MDA) and nitric oxide (NO) in patients with acute respiratory distress syndrome. There were also different levels of oxidative stress markers in non-survivor compared with survivor groups. Increased level of an oxidant like a thiobarbituric acid substance with malondialdechyde (TBS_MDA) and antioxidant glutathionperoxidase (GPx) at the first day after inclusion was related with poor outcome in patients with acute respiratory distress syndrome.

Error of Acid Rain Research, Effect of Atmosphere CO2 Ignored

Since the concept of acid rain was come up with time has been for a little more than a hundred years. Many researchers have studied the causes of it formation and obtained some results. But a satisfactory explanation can not be given about some phenomena of acid rain until today. For example in some regions the acid substances in atmosphere before formed acid rain are being reduced year after year but acidity of rainwater and acid rain frequency are being increased year after year. The anions are less than cations in acid rain, and so on. In order to solve these problems we have done simulated tests. Here we show that the cause of unaccountability some acid rains is ignored effect of atmosphere CO2. Firstly, CO2is well-known acid substance, it can make water acid and its amount is ten thousand times as much as other acid substances, for example SO2and NOx, in atmosphere. Then, when CO2was not dissolved in solution of simulated acid rain pH of solution was larger than 6 although the ions percentage composition of solution is as same as acid rain, and when CO2was done pH of solution was less than or equal 4.6. So, we concluded that CO2plays an important role in acid rain forming.

The mechanism of ciliary movement. —V. The effect ions the duration of beat

In a previous paper (Gray, 1924) it was shown that the whole series of events which accompany continuous ciliary movement is divisible into at least three phases: (i) A reaction which is sensitive to monovalent cations (particularly the hydrogen-ion); any interference with this mechanism involves a change in the rate of beat of the cilia, and ultimately leads to a corresponding change in the oxygen consumption of the cells, (ii) A mechanism which is brought into operation by the presence of an activating acid substance, (iii) A reaction of an oxidative nature which removes some factor which is the direct result of activity and which, if allowed to accumulate, will inhibit the activity of the whole ciliary apparatus. The present paper deals primarily with the first of these processes. For this purpose the lateral epithelium on the gills of Mytilusedulis form a convenient material, since under appropriate conditions the cilia of these cells can (for many hours after excision of the gill) either be maintained in an active state of movement or be kept quite motionless. If the gills of a healthy animal be excised and examined at once under the microscope, the lateral cilia are seen to be in active movement, and exhibit a very beautiful metachronial rhythm which passes up and down the two sides of the gill-filaments. If these gills are now thoroughly washed with sea-water the lateral cilia sooner or later come to rest; the period which elapses before quiescence varies considerably with different individuals. It is usually about 15 mins., but it may be considerably longer in the case of well-fed mussels. It is to be concluded that the amount of available energy in the lateral epithelium is usually sufficient to maintain activity in sea-water for a strictly limited period. This is in marked contrast to the frontal epithelium, which remains active in sea-water for very long periods; in this case it may be assumed that the supply of energy is still being maintained from the glycoprotein (Gray 1924).