[Visual acuity charts in the Russian Empire, the USSR and modern Russia]. / Tablitsy dlya opredeleniya ostroty zreniya v Rossiiskoi imperii, SSSR i sovremennoi Rossii.

Visual acuity is the quantitative parameter of the visual system characterizing its functional spatial resolution. Special test charts are commonly used for visual acuity assessment. The development of foreign tests for visual acuity is comprehensively covered in the literature, while the history of improving visual acuity charts in modern Russia, the USSR, and in the territory of the Russian Empire is only considered fragmentarily. In particular, there are almost no mentions of D.A. Sivtsev's work on proper letter-signs selection, and of A.A. Kryukov's tests. The purpose of this article is to review the history of developing visual acuity assessment methods in the Russian Empire, the USSR and modern Russia. One of the first sets of tests for visual acuity assessment available in the Russian Empire was developed by A.A. Kryukov; it was republished several times, but some criticism of the test can be encountered in the literature of that period. Subsequently, a task of developing a more accurate method was presented, which was implemented in the form of several editions of the visual acuity charts by D.A. Sivtsev and S.S. Golovin. The authors put a lot of effort into selecting the letters for the most reliable results of visual acuity assessment, excluded some unsuccessful characters (Cyrillic letters 'Ж' and 'Ю') and changed the size levels of the chart (the lines corresponding to the visual acuity levels of 1.25 and 1.5 were substituted by 1.5 and 2.0). Around the same period, A. Holina's chart appeared in print, but due to its poor structure the chart did not gain popularity, although it had a number of advantages. The review also considers some modern tests: the RORBA chart (named after the authors Rosenbaum, Ovechkin, Roslyakov, Bershanskiy, Aizenshtat), the vanishing optotypes by S.A. Koskin et al., the three-bar optotypes by the Institute for Information Transmission Problems (IITP), and the "Quartet" optotypes. Despite a large number of options, the search for the best method of measuring visual acuity for various medical and scientific tasks continues.

[Olfactory disorders as a multidisciplinary problem]. / Rasstroistva obonyaniya ­ mezhdistsiplinarnaya problema.

Olfactory dysfunction is a serious symptom that requires careful differential diagnosis. The article presents convincing evidence that dysosmia is not only a symptom of rinological pathology, but also a manifestation of various neurodegenerative diseases. Some patients with SARS-CoV-2 have neurological symptoms. Modern studies show that olfactory and gustatory dysfunctions are significant symptoms in the clinical presentation of the COVID-19 infection. The importance of olfactory diagnostics in relatives of patients with hereditary neurodegenerative diseases for the purpose of early detection of pathology is noted. We consider the possibility of introducing new methods for the diagnosis of olfactory dysfunction, which is a promising task both in the field of neurology and otorhinolaryngology, in order to prevent the development of neurodegenerative diseases at an early stage, improve the quality of life and social adaptation of patients.

[Smell impairment in COVID-19 patients: mechanisms and clinical significance]. / Narushenie obonyaniya u bol'nykh COVID-19: mekhanizmy i klinicheskoe znachenie.

Numerous studies have shown that loss of smell is a serious symptom that requires careful differential diagnosis. There is convincing evidence that a violation of the sense of smell is not so much a sign of the pathology of the nasal cavity and paranasal sinuses, but it can be a manifestation of neurodegenerative diseases. Some patients with the identified SARS-CoV-2 virus have neurological symptoms. Most of them are not specific - headache, dizziness, fatigue, myalgia. A small percentage of patients with COVID-19 infection have convulsions, impaired consciousness, and the presence of 2019-NCoV RNA was found in the cerebrospinal fluid. Data on the development of new symptoms of the disease, in the form of anosmia and dysgeusia, are presented.

[Paresthesias of the upper respiratory tract in the patients of the elder age group]. / Parestezii verkhnikh dykhatel'nykh putei u patsientov starshei vozrastnoi gruppy.

The present study was designed to carry out the comprehensive clinical examination of 120 patients presenting with paresthesia of the upper respiratory tract (42 men (35%) and 78 women (65%P) aged 56 to 90 years). The most frequent complaints included cough (72%), globus sensation (46%), itching (43%), dry throat (38%), and difficulty of swallowing (28%). The duration of the clinical symptoms ranged from 1 month to 3 years (m±M: 1+to 1.46). The etiological factors behind paresthesias in the patients of the older age groups in comparison with the patients below 55 years of age included gastroenterological and cardiovascular diseases, pathology of the broncho-pulmonary system, and neurological pathology. ENT pathology was diagnosed equally often in the patients of both groups. Endocrine pathology and stress-associated conditions occurred more frequently in the patients below the age of 55 years. The intolerance of drugs was more commonly encountered in the patients of the older age group (amounting up to 35%). It is concluded that the ultimate etiological factor of paresthesia of the upper respiratory tract can be deduced based on the detection of a particular disease and the analysis of the dynamics of the patients' complaints after the completion of the adequate treatment.

[Paresthesias of the upper respiratory tract].

This review concerns the modern views of etiology, diagnostics, and treatment of the patients presenting with paresthesias of the upper respiratory tract. Various concepts of etiology of this pathology are described along with the relevant diagnostic and therapeutic approaches. Special attention is given to the debatable aspects of diagnostics and treatment of the patients complaining of the feeling of a lump in the throat ("globus sensation"). The opinions of the domestic and foreign authors concerning this problem are considered. The necessity of the search for the new additional therapeutic procedures for the treatment of paresthesias of the upper respiratory tract, including the non-medicamental modalities, is substantiated. It is concluded that the development of the new adequate diagnostic and therapeutic algorithm is indispensable for the enhancement of the effectiveness of the management of the patients with paresthesias of the upper respiratory tract and complaints of "globus sensation".

Changes in the redox potential and catalase activity of Mn2+ ions during formation of Mn-bicarbonate complexes.

Changes in the redox potentials of Mn2+ ions and Mn-bicarbonate complexes were studied due to their possible participation in the photosynthetic oxidation of water in plant photosystem 2 and in H2O2 decomposition. Electrochemical oxidation of Mn2+ ions was demonstrated by voltammetry on a platinum electrode in 0.1 M LiClO4 solution at a potential of 1.19 V (vs NHE). When NaHCO3 was added, the oxidation peak of Mn2+ ions disappeared. New oxidation peaks appeared at 0.92 V and 0.63 V which corresponded to the oxidation of Mn(HCO3)+ and Mn(HCO3)2, respectively, generated by complex formation between Mn2+ and HCO3- ions. The effect of the Mn(2+)-bicarbonate complex on H2O2 redox decomposition was studied. It was shown that the addition of MnSO4 to the H2O2 solution did not affect the H2O2 oxidation peak height thereby indicating the absence of H2O2 decomposition by Mn2+ ions. At the same time, subsequent addition of NaHCO3 resulted in the disappearance of the oxidation peaks of both H2O2 and Mn2+. As at pH 7 the thermodynamic potential of H2O2 reduction is 1.1 V and the Mn2+ oxidation potential is 1.19 V, the redox reaction between them is hampered. Formation of the Mn(2+)-bicarbonate complex shifted the Mn2+ oxidation potential to 0.63 V, thereby inducing the decomposition of H2O2. It is suggested that the decrease in the Mn2+ oxidation potential resulting from the formation of the bicarbonate complex determines the bicarbonate capability to enhance the Mn2+ ability to donate electrons for PS 2 reaction centres.

[Participation of its reaction center in the electrochemical reduction of ferredoxin]. / Ob uchastii v élektrokhimicheskom vosstanovlenii ferredoksina ego reaktsionnogo tsentra.

In the experiments with reaction center modification of ferredoxin its participation in reduction has been shown. Polarographic characteristics of ferredoxin and apoferredoxin have been compared. While removing iron and labile sulphur from ferredoxin reaction center the reduction wave of Fe-S bonds with E 1/2 = -0.33 V (N. H. E.) transforms into the reduction wave of S-S bonds with E 1/2 = -0,39 V at pH = 7.

[Oxidation-reduction potentials of chlorophyll pigments in photosynthesizing organisms on different levels of evolutionary development]. / Okislitel'no-vosstanovitel'nye potentsialy khlorofillovykh pigmentov fotosinteziruiushchikh organizmov, stoiashchikh na raznykh urovniakh évoliutsionnogo razvitiia

According to polarographically measured EOred of bacteriochlorophyll "a", chlorobium chlorophyll "660", "b" and "a" chlorophylls (-0.67 V, -0.73 V, -0.79 V, -0.86 V-n.h.e.) and literature data about Eoox of these pigments (+/-0.62 V, + 0.62 V, + 0.78 V, +0.77 V correspondingly) it has been shown that chemical energy stored in the singular photochemical set is increased in the evolution of the photosynthetic apparatus. It has apparently resulted in the possibility of evolutionary approach to utilization of more inert and more accessible (water) electron donors and favoured further development of photosynthesizing organisms.

[Ferredoxin reduction by polarographic methods]. / O vosstanovlenii ferredoksina poliarograficheskimi metodami

The reduction of iron-sulphur protein of the higher plant ferrodoxin has been studied by polarographical methods. Ferredoxin initiates a reversible wave with E1/2=--0,61 v (N. C. E.) at pH 7. Protein absorption greatly influences the electrochemical reduction. The protons have been shown to take part in the electrode reaction. The potentiometrically obtained data about the difference between E1/2 and E0=--0.70 v and its causative factors are discussed. As a result of the experiments with modification of ferredoxin active centre it has been concluded that the active centre participates in the polarographical reduction.