Bismuth Nanoparticles Increase Effectiveness of Proton Therapy of Ehrlich Carcinoma.

We studied the antitumor activity of the combined use of local proton irradiation in two modes (10 and 31 Gy) with preliminary intra-tumoral injection of two types of bismuth nanoparticles differing in surface coating: coated with the amphiphilic molecule Pluronic-F127 or Silane-PEG (5 kDa)-COOH polymer. Nanoparticles were used in doses of 0.75 and 1.5 mg/mouse. In two independent series on experimental tumor model (solid Ehrlich carcinoma), bismuth nanoparticles of both modifications injected directly into the tumor enhanced the antitumor effects of proton therapy. Moreover, the radiosensitizing effect of bismuth nanoparticles administered via this route increased with the increasing the doses of nanoparticles and the doses of radiation exposure. In our opinion, these promising data obtained for the first time extend the possibilities of treating malignant neoplasms.

Binary Proton Therapy of Ehrlich Carcinoma Using Targeted Gold Nanoparticles.

Proton therapy can treat tumors located in radiation-sensitive tissues. This article demonstrates the possibility of enhancing the proton therapy with targeted gold nanoparticles that selectively recognize tumor cells. Au-PEG nanoparticles at concentrations above 25 mg/L and 4 Gy proton dose caused complete death of EMT6/P cells in vitro. Binary proton therapy using targeted Au-PEG-FA nanoparticles caused an 80% tumor growth inhibition effect in vivo. The use of targeted gold nanoparticles is promising for enhancing the proton irradiation effect on tumor cells and requires further research to increase the therapeutic index of the approach.

[Study of antitumor effects of human placenta hydrolysate on PC-3, OAW-42, BT-474 cell cultures].

AIM: To investigate the antitumor effects of human placenta hydrolysate (HPH) peptides on three hormone-dependent human cell lines: prostate adenocarcinoma, breast carcinoma, and ovarian cancer by metabolic analysis of cell cultures. MATERIALS AND METHODS: The effect of HPH on tumor and control tumor cell lines was evaluated. Study stages: (A) de novo peptide sequencing by collision-induced dissociation mass spectrometry; (B) detection of peptides with anti-tumor properties; (C) expert analysis of the obtained lists of peptides. RESULTS: Dose-dependent cytotoxic effects of HPH on three tumor cell lines are shown: PC-3 (human prostate adenocarcinomas), OAW-42 (human ovarian cancer), BT-474 (human breast carcinomas), and IC50 constants (1.3-2.8 mg/ml) were obtained. The analysis of the HPH peptide fraction showed more than 70 peptides with antitumor properties in the composition of this HPH, including kinase inhibitors: mitogen-activated protein kinases, kappa-bi nuclear factor inhibitor kinase, AKT serine/threonine kinase 1, protein kinase C zeta, interleukin-1 receptor-associated kinase 4 and cyclin-dependent kinase 1. CONCLUSION: The results of the study indicate not only the oncological safety of the HPH used in therapy but also the mild antitumor effects of this HPH at high concentrations.

Comparison of Direct Counts and Conductometric Measurements on a Hematology Analyzer Abacus Junior 5 Vet Myelokaryocyte Content in the Red Bone Marrow of Mice.

We studied the possibility of conductometric measurement of myelokaryocyte content in the red bone marrow of mice using a hematological Abacus Junior 5 Vet analyzer (Diatron). Statistical, correlation, and regression analyses were performed to assess of the results of myelokaryocyte counting in the suspensions of mouse red bone marrow by a direct method in cytometers and by using Abacus Junior 5 Vet analyzer. It was shown that in both intact mice and animals with modelled red bone marrow hypoplasia, irrespectively of the state of hematopoiesis in representative samples, conductometric measurements of myelokaryocyte content on the Abacus analyzer with high confidence reproduced direct counting results (in different tests p=0.64-0.82, p=0.83-0.98). This indicates that myelokaryocyte counting on the Abacus Junior 5 Vet analyzer can be an acceptable alternative to counting chamber measurements in mouse samplings. However, the variability of single measurements with the Abacus Junior 5 Vet in red bone marrow suspensions is high (5%) and this has to be considered in small samples.

In Vitro Antiviral Activity of a New Indol-3-carboxylic Acid Derivative Against SARS-CoV-2.

The coronavirus disease (COVID-19) pandemic has brought into sharp relief the threat posed by coronaviruses and laid the foundation for a fundamental analysis of this viral family, as well as a search for effective anti-COVID drugs. Work is underway to update existent vaccines against COVID-19, and screening for low-molecular-weight anti-COVID drug candidates for outpatient medicine continues. The opportunities and ways to accelerate the development of antiviral drugs against other pathogens are being discussed in the context of preparing for the next pandemic. In 2012-2015, Tsyshkova et al. synthesized a group of water-soluble low-molecular-weight compounds exhibiting an antiviral activity, whose chemical structure was similar to that of arbidol. Among those, there were a number of water-soluble compounds based on 5-methoxyindole-3-carboxylic acid aminoalkyl esters. Only one member of this rather extensive group of compounds, dihydrochloride of 6-bromo-5-methoxy-1-methyl-2-(1-piperidinomethyl)-3-(2-diethylaminoethoxy) carbonylindole, exhibited a reliable antiviral effect against SARS-CoV-2 in vitro. At a concentration of 52.0 µM, this compound completely inhibited the replication of the SARS-CoV-2 virus with an infectious activity of 106 TCID50/mL. The concentration curves of the analyzed compound indicate the specificity of its action. Interferon-inducing activity, as well as suppression of syncytium formation induced by the spike protein (S-glycoprotein) of SARS-CoV-2 by 89%, were also revealed. In view of its synthetic accessibility - high activity (IC50 = 1.06 µg/mL) and high selectivity index (SI = 78.6) - this compound appears to meets the requirements for the development of antiviral drugs for COVID-19 prevention and treatment.

Comparison of Antitumor Effects of Combined and Separate Treatment with NO Synthase Inhibitor T1023 and PDK1 Inhibitor Dichloroacetate.

Combined chronic treatment of Ehrlich solid carcinoma (EC) with an NOS inhibitor 1-isobutanoyl-2-isopropylisothiourea hydrobromide (T1023) and a PDK1 inhibitor dichloroacetate was accompanied by statistically significant synergetic antitumor effects manifested in a significant and stable suppression of neoplasm growth (by 55-65%). Separate treatment with T1023 and dichloroacetate induced moderate short-term inhibition of tumor growth (by 30-35%) followed by weakening of tumor sensitivity to these substances. These results attest to synergetic antitumor effects NOS inhibitor T1023 and PDK1 inhibitor dichloroacetate producing antiangiogenic and hypoxia-targeted cytotoxic effects, during their combined administration, which allows overcoming the adaptive potential of the tumors.

[Evaluation of the antitumor potential of cerebrolysin]. / Otsenka protivoopukholevogo potentsiala tserebrolizina.

AIM: To investigate the effect of cerebrolysin on the growth and metastasis of malignant tumors in mice (a model of lung carcinoma Lewis). MATERIAL AND METHODS: The study was performed on 60 male mice, hybrids F1 (the age of 2-2.5 months, body weight 19-22g.). Transplantable epidermoid Lewis lung carcinoma (LLC) was used as a standard experimental model to evaluate the properties of the potential antitumor agents. Experimental animals were administered a single intraperitoneal injection of cerebrolysin in doses of 524 mg/kg (n=20) and 1800 mg/kg (n=20) daily from 2 to 16 days after tumor transplantation. RESULTS AND CONCLUSION: Compared with the control group (n=20), cerebrolysin induced growth inhibition of LLC during the treatment (7 to 16 days). An impact of the drug was accompanied by the inhibition of the tumor growth rate by 10-15% (p<0.05). Cerebrolysin demonstrated a dose-dependent effect of reducing the large number of metastases: a number of large metastases significantly decreased by 30-50% with the increase of cerebrolysin dose (p=0.01). Cerebrolysin can significantly suppress the growth rate of Lewis lung carcinoma.

[Radioprotective Properties of NO-Synthase Inhibitor T1023: I. Indicators of Radioprotective Activity and Interaction with Other Radioprotectors].

The study of radioprotective activity of NO-synthase inhibitor, N-S-isothiourea derivative T1023 showed that this compound has a significant therapeutic range of radioprotective activity (5.5-6.0) and its optimal radioprotective dose is 1/4 LD16. The value of its Radiation Dose-Reduction Factor totaled 1.4-1.8. We have demonstrated a pronounced pharmacodynamic interaction of T1023 with some known radioprotectors. The character of the interaction was determined by its vasoactive properties. Combined use of T1023 and cystamine, which causes a decrease in vascular tone, was accompanied by a statistically significant weakening of the radioprotective effect. But, the combined use of T1023 with serotonergic and adrenergic radioprotectors having a pressor action caused a statistically significant increase in the radioprotective effect. Moreover, T1023 combined with such radioprotectors caused the synergistic radioprotective effect even when used at small doses that do not have any radioprotective effect alone. The findings suggest that NOS inhibitors can be effective radioprotectors and are able to create new opportunities for the development of safer radioprotective agents. The very same compound T1023, according to current criteria of pharmacological screening, is certainly promising for further investigations.

[Radioprotective Properties of NO-synthase Inhibitor T1023: II. The Ability for Selective Protection of Normal Tissues During Radiotherapy of Tumors].

We studied the effect of T1023, NO-synthase inhibitor, N-acyl-S-alkyl-isothiourea in a single administration at a dose of 75 mg/kg on the growth of transplantable rat sarcoma M-1 and the development of acute skin reactions after the local impact of γ-radiation at the doses of 32 and 36 Gy. The results showed that the T1023 at a single dose had no effect on the growth of sarcoma, and did not modify the radiosensitivity of the tumor and anti-tumor efficacy of γ-rays. However, at both doses T1023 significantly reduced the severity of acute radiation skin reactions. NOS inhibitor did not change the duration of the inflammatory and regenerative processes, but significantly limited the degree of radiation alteration of the deep layers of the skin and underlying tissues. The findings suggest that the hypoxic mechanism of antitumor action allows T1023 to selectively protect the non-malignant tissue during radiation therapy of solid tumors. Therefore, this compound may be regarded as a promising basis for the development of pharmacological prevention of radiotherapy complications.

[On the mechanism of radioprotective effect of NO-synthase inhibitors].

We studied the influence on hemodynamics and radioprotective activity of two inhibitors of NO-synthase (NOS)--isothiourea derivatives with different NOS isoform selectivity: T1023--a selective inhibitor of endothelial and inducible NOS; and NTT2--a highly selective inhibitor of neuronal NOS. Both compounds at a dose of 1/7 LD50/15 caused a vasopressive effect and baroreflex response in normal Wistar rats. However, the nature of hemodynamic changes was qualitatively different. T1023 caused a prolonged elevation of vascular tone and reflex shift resulted in a significant and lasting reduction in the systemic blood flow (35-45%), which created conditions for the development of circulatory hypoxia. The use of NTT2 caused a reflex change in hemodynamics accompanied by vasodilation; and systemic blood flow was maintained at the initial level. T1023 effectively protected mice subjected to 10 Gy γ-irradiation and their bone marrow stem cells irradiated with 6 Gy, not yielding to the radioprotective effect of cystamine. NTT2 at these doses did not show any radioprotective effect. The obtained results support the leading mechanism of the radioprotective effect of NOS inhibitors is the induction of hypoxia. With this mechanism of action a significant radioprotective activity can be expected for the inhibitors which effectively suppress primarily endothelial NOS.

[Effect of mesenchymal stem cells and entero-absorbent on cardiac function in rats following local irradiation of the chest].

Cardiac function in Wistar male rats was assessed by ECG records for 28 days following exposure of the chest to γ-rays at a dose of 6 Gy, dose rate 4 Gy/min. The exposed rats experienced a moderate cardiac ischemia and a certain increase in the load on the atria. The use of clay of Kaluga deposit and mesenchymal stem cells reduced the adverse radiation effects.

[Radioprotective properties of isothiourea derivatives with NO-inhibitory mechanism of action].

The study of the radioprotective activity of S-[2-alkyl (aryl) sulfonyl]-S-ethyl derivatives of (vinyl)-isothiourea in (he model of the survival of mice exposed to gamma-radiation at a dose of 10 Gy has shown that the incorporation of additional sulfur-containing groups does not increase the radioprotective properties of compounds. In contrast to aminoalkil thiols, the effectiveness of the radiation protection action of the isothiourea (ITU) derivatives studied clearly correlates with the NO-inhibitory activity. This fact allowed us to assume that the radioprotective effect of S-substituted ITU caused inhibition of the endogenous synthesis of NO, which promotes the development of circulatory hypoxia, and that a further search for the radioprotective agents in this class of chemicals should be considered as the search for effective inhibitors of NO-synthase (NOS). The theoretical analysis of the conformity of molecular structures to the composition and topology of the active center of NOS-inhibitors allowed us to prognosticate a number of new ITU derivatives with the potential NOS-inhibiting ability. As a result of further theoretical and experimental studies, four S,N-disubstituted ITU derivatives - active non-selective NOS-inhibitors, were first identified and synthesized. These compounds exhibited a pronounced and prolonged vasopressive effects at doses of 0.01-0.05 LD50/15 in the models of severe hemorrhagic and endotoxic shock, and provided 65-100% 30-day survival at doses of 0.2-0.3 LD50/15 in the mice irradiated by gamma-rays at a dose of 10 Gy (LD98/30).The findings suggest the pronounced radioprotective effect of NOS-inhibitors among the ITU-derivatives.

[Experimental study of the effect of detoxification with enterosorbents on the function of irradiated myocardium].

Increase in intoxication products, such as medium size peptides, indole and myoglobin, in urine was observed in Wistar rats after exposure of their chest to gamma-radiation at a dose of 6 Gy (dose rate 4 Gy/min). The rats exhibited moderate ischemic ECG. Administration of enterosorbents, such as Smekta and Clay of Kaluga deposit, to the irradiated rats resulted in the decrease of the toxicant content in the animals and the recovery of the cardiac function on the 28th day. These sorbents had practically a similar efficacy.

Effect of NO inhibitors on hypovolemic shock-induced hypotension.

In vivo effect of isothiourea derivatives on NO production was studied by the method of electron paramagnetic resonance spectroscopy with a spin trap. We evaluated the influence of these compounds on hemodynamic parameters in anesthetized rats with hypovolemic shock. A correlation was found between the size of S,N-substituents in isothiourea derivatives (methyl, ethyl, and isopropyl) and NO inhibitory activity of compounds. The antihypotensive effect was more pronounced in compounds with high NO inhibitory activity containing the isopropyl radical.

Effect of NO synthase inhibitor 2-amino-5,6-dihydro-4H-1,3-thiazine on endotoxin-induced changes in hemodynamic parameters and respiration in rats.

We studied the effect of NO synthase inhibitor 2-amino-5,6-dihydro-4H-1,3-thiazine (2-ADT) on the cardiovascular system in rats with endotoxic shock. Blood pressure, heart rate, and respiratory rate were recorded. E. coli lipopolysaccharide decreased blood pressure and heart rate. 2-ADT in a dose of 5 mg/kg normalized these hemodynamic parameters. The normalizing effect of 2-ADT decreased with increasing the dose of this preparation. 2-ADT in high doses (10, 20, and 30 mg/kg) and repeated injections of the preparation caused death of experimental animals.

NO-inhibiting and vasotropic activity of some compounds with thioamidine group.

Using the method of electron paramagnetic spectroscopy we demonstrated that thiazine-thiazoline compounds and aminoethyl isothiourea containing the thioamidine group inhibit NO production in the liver of endotoxin-treated mice. Injection of these agents to anesthetized rats increased arterial pressure and enhanced respiration rate. This effect probably reflects inhibition of not only inducible, but also the constitutive synthesis of NO by compounds with thioamidine group.

[Surgical correction of incomplete form of open atrioventricular canal in adults]. / Khirurgicheskaia korrektsiia nepolnoi formy otkrytogo atrioventrikuliarnogo kanala u vzroslykh.

Clinical and anatomo-hemodynamic features of adult patients with incomplete form of the open atrioventricular canal are presented, policy of surgical treatment and optimal degree of surgical intervention on mitral valve are determined. The study of variant anatomy of the defect, revealed two variants of left atrioventricular valve formation (with "functional" and with "anatomical" septal commissure). In the first anatomic variant the mitral insufficiency was hemodynamically important and required surgical correction. In the second variant, the mitral valve had good closure function, that permitted to avoid the routine suturing of anterior velum's splitting.

[Program of examination for patients with isolated mitral valve defects to evaluate the degree of pulmonary hypertension]. / Programma obsledovaniia bol'nykh s izolirovannymi mitral'nymi porokami serdtsa dlia otsenki stepeni legochnoi gipertenzii.

98 patients with isolated rheumatic mitral valve defects of the heart entered the study. Their central hemodynamics was studied intraoperatively before surgical correction of the defect. The results were compared to those provided by conventional noninvasive methods: chest x-ray, ECG, echo-CG, external respiration function test. Correlation analysis using computer intellect PolyAnalyst v.1.01R helped to design a program and practical nomogram which can quantitatively determine the degree of pulmonary hypertension on the basis of digital values of Rv1 wave amplitude (ECG) and right ventricular cavity size (echoCG).

[Experimental assessment of the cardiovascular system functional state in rats after chronic gamma-irradiation in various absorbed doses]. / Eksperimental'naia otsenka funktsional'nogo sostoianiia serdechno-sosudistoi sistemy u krys posle khronicheskogo gamma-oblucheniia v raznykh pogloshchennykh dozakh.

Prolonged anthenatal gamma-irradiation of rats with total doses of 1.25; 1.9 and 2.5 Gy resulted in discoordination of cardiovascular system function. This study confirm our previous data on negative effect of chronic gamma-irradiation on forming and development of the functional systems in the anthenatally irradiated organism.