Sequence of Structural and Magnetic Phase Transitions in (NO)Mn6(NO3)13

New nitrosonium manganese(II) nitrate, (NO)Mn6(NO3)13, has been synthesized and structurally characterized. In the temperature range of 45-298 K, the crystal is hexagonal (centrosymmetric sp. gr. P63/m). Mn2+ ions are assembled into tubes along axis c with both NO3- filling and coating. The nitrosonium cation is located in the framework cavity and is disordered by a 3-fold axis. At the temperature TS1 = 190 K, a structural phase transition related to the libration of the intertube NO3 group and a small variation of Mn polyhedron is observed. Moreover, the anomalies in physical properties of (NO)Mn6(NO3)13 allow suggesting that ordering of NO+ units occurs at low temperatures. The antiferromagnetic ordering in this compound is preceded by the formation of a short-range correlation regime at about 25 K and takes place in two steps at TN1 = 12.0 K and TN2 = 8.4 K.

A high-pressure single-crystal X-ray diffraction study of potassium guaninate hydrate, K+·C5H4N5O-·H2O

The crystal structure of potassium guaninate hydrate, K+·C5H4N5O-·H2O, was studied in the pressure range of 1 atm to 7.3 GPa by single-crystal diffraction using synchrotron radiation and a laboratory X-ray diffraction source. Structural strain was compared to that of the same salt hydrate on cooling, and in 2Na+·C5H3N5O2-·7H2O under hydrostatic compression and on cooling. A polymorphic transition into a new, incommensurately modulated, phase was observed at ∼4-5 GPa. The transition was reversible with a hysteresis: the satellite reflections disappeared on decompression to ∼1.4 GPa.

Non-Fermi-Liquid Behavior of Superconducting SnH4

The chemical interaction of Sn with H2 by X-ray diffraction methods at pressures of 180-210 GPa is studied. A previously unknown tetrahydride SnH4 with a cubic structure (fcc) exhibiting superconducting properties below TC  = 72 K is obtained; the formation of a high molecular C2/m-SnH14 superhydride and several lower hydrides, fcc SnH2 , and C2-Sn12 H18 , is also detected. The temperature dependence of critical current density JC (T) in SnH4 yields the superconducting gap 2Δ(0) = 21.6 meV at 180 GPa. SnH4 has unusual behavior in strong magnetic fields: B,T-linear dependences of magnetoresistance and the upper critical magnetic field BC2 (T) ∝ (TC - T). The latter contradicts the Wertheimer-Helfand-Hohenberg model developed for conventional superconductors. Along with this, the temperature dependence of electrical resistance of fcc SnH4 in non-superconducting state exhibits a deviation from what is expected for phonon-mediated scattering described by the Bloch-Grüneisen model and is beyond the framework of the Fermi liquid theory. Such anomalies occur for many superhydrides, making them much closer to cuprates than previously believed.

Comparative study of calcification in human choroid plexus, pineal gland, and habenula

Choroid plexus, pineal gland, and habenula tend to accumulate physiologic calcifications (concrements) over a lifetime. However, until now the composition and causes of the intracranial calcifications remain unclear. The detailed analysis of concrements has been done by us using X-ray diffraction analysis (XRD), X-ray diffraction topography (XRDT), micro-CT, X-ray phase-contrast tomography (XPCT), as well as histology and immunohistochemistry (IHC). By combining physical (XRD) and biochemical (IHC) methods, we identified inorganic (hydroxyapatite) and organic (vimentin) components of the concrements. Via XPCT, XRDT, histological, and IHC methods, we assessed the structure of concrements within their appropriate tissue environment in both two and three dimensions. The study found that hydroxyapatite was a major component of all calcified depositions. It should be noted, however, that the concrements displayed distinctive characteristics corresponding to each specific structure of the brain. As a result, our study provides a basis for assessing the pathological and physiological changes that occur in brain structure containing calcifications.

[Clinical, biochemical and histological indicators of Del Nido cardioplegia efficacy in patients with severe myocardial hypertrophy]

OBJECTIVE

To evaluate the effectiveness of two cardioplegia techniques in patients with severe myocardial hypertrophy undergoing septal myectomy or aortic valve replacement.

MATERIAL AND METHODS

A comparative pilot prospective single-center randomized study included 46 patients between 2022 and 2023. Patients were randomized into 2 groups: Del Nido (n=23) and Custodiol (n=23). We analyzed perioperative echocardiography data, troponin I at several time points, perioperative complications and histological data.

RESULTS

Both groups were comparable in time of myocardial ischemia, cardiopulmonary bypass, duration of anesthesia and surgery (p>0.05). The maximum ischemia time in the Del Nido group was 84 min. The same group showed significantly higher percentage of spontaneous rhythm recovery (65.2% vs. 30%, p=0.008). None patient required mechanical support, high-dose inotropes or vasopressors. Troponin I in 2 hours after cardiopulmonary bypass (p=0.415), 12 (p=0.528) and 24 hours after admission to the intensive care unit (p=0.281) were similar in both groups. No significant difference was found in ventilation time, ICU- and hospital-stay.

CONCLUSION

Del Nido cardioplegia has some advantages compared to Custodiol and does not lead to perioperative complications in case of aortic cross-clamping time <90 min in patients with myocardial hypertrophy.

Effect of Magnetic Impurities on Superconductivity in LaH10

Polyhydrides are a novel class of superconducting materials with extremely high critical parameters, which is very promising for sensor applications. On the other hand, a complete experimental study of the best so far known superconductor, lanthanum superhydride LaH₁₀ , encounters a serious complication because of the large upper critical magnetic field H_C2 (0), exceeding 120-160 T. It is found that partial replacement of La atoms by magnetic Nd atoms results in significant suppression of superconductivity in LaH₁₀ : each at% of Nd causes a decrease in T_C by 10-11 K, helping to control the critical parameters of this compound. Strong pulsed magnetic fields up to 68 T are used to study the Hall effect, magnetoresistance, and the magnetic phase diagram of ternary metal polyhydrides for the first time. Surprisingly, (La,Nd)H₁₀ demonstrates completely linear H_C2 (T) ∝ |T - T_C |, which calls into question the applicability of the Werthamer-Helfand-Hohenberg model for polyhydrides. The suppression of superconductivity in LaH₁₀ by magnetic Nd atoms and the robustness of T_C with respect to nonmagnetic impurities (e.g., Y, Al, C) under Anderson's theorem gives new experimental evidence of the isotropic (s-wave) character of conventional electron-phonon pairing in lanthanum decahydride.

Nonstoichiometric Ellenbergerite-Type Phosphates: Hydrothermal Synthesis, Crystal Chemistry, and Magnetic Behavior

We synthesized single crystals of Na_0.55Ni₆(OH)₃(H_0.61PO₄)₄ (I) and polycrystals of (Na, Ni)_0.64Ni_5.68(OH)₃(H_0.67PO₄)₄ (II) with ellenbergerite-like structures using the hydrothermal method. The phases crystallize in the hexagonal space group P6₃mc with the following unit cell parameters: a = 12.5342(1) Å, c = 4.9470(1) Å, and V = 673.08(2) ų for I; a = 12.4708(2) Å, c = 4.9435(2) Å, and V = 665.82(2) ų for II; and Z = 2. Their crystal structures are based on a 3D framework built from NiO₆ octahedra and PO₄ tetrahedra. The difference between I and II lies in the way the structural channels are filled along the [001] direction. These channels accommodate segments of Na- and (Na, Ni)-centered chains of face-sharing octahedra in the structures I and II, respectively. The magnetic susceptibility χ and the specific heat C_p evidence pronounced low-dimensional magnetic behavior at elevated temperatures and the formation of the weakly ferromagnetic long-range order at T_N^I = 61 K and T_N^II = 63 K. Analysis of the χ(T) data within both chain and dimer spin models allows the estimation of the leading exchange interaction parameters in the compounds under study.

[Primary delayed growth of the right and left atrial myxoma]

There is more than 58-year experience of surgical treatment of patients with intracardiac myxomas at the Petrovsky National Research Center of Surgery. Primary delayed growth of the right and left atrial myxoma after 21 years and 5 months was observed only in 1 (0.36%) patient. Transthoracic echocardiography was used for diagnosis of tumors. Tumors were totally resected including adjacent parts of myocardium or subendocardial tissue with subsequent cautery. In-hospital mortality was absent. There were no recurrent myxomas throughout subsequent 10-year follow-up.

An Orthorhombic Modification of KCoPO4 Stabilized under Hydrothermal Conditions: Crystal Chemistry and Magnetic Behavior

A novel modification of the KCoPO₄, δ-phase has been prepared by hydrothermal synthesis at 553 K. The compound crystallizes in the orthorhombic system with the unit-cell parameters a = 8.5031(8), b = 10.2830(5), c = 54.170(4) Å. The crystal structure was determined based on synchrotron low-temperature single-crystal X-ray diffraction data obtained from an inversion twin in the space group P2₁2₁2₁ and refined to R = 0.077 for 5156 reflections with I > 3σ(I). The δ-KCoPO₄ possesses a new structure type which is based on a framework built from sharing vertices Co- and P-centered tetrahedra. The {CoPO₄^-}_∞ construction of tetrahedra may be described as assembled from networks formed by two topologically diverse six-membered rings of tetrahedra stacked together through vertex-bridging contacts along the a axis. The ratio of the (UUUDDD) and (UUDUDD) rings, where (U) and (D) denote the orientation of the tetrahedra in the six-membered rings up and down relative to the plane grids, is equal to 5:1. The (UUDUDD) rings form bands parallel to the [010] direction each surrounded from both sides along the c axis by slabs of five ribbons width having alternative (UUUDDD) topology. Open in the [100] direction channels incorporate K⁺ ions; this structural feature permits to suppose ion-conductive and/or electrochemical properties of the title compound. The possible mechanism of the δ → γ phase transition is discussed on the basis of the crystal chemical analysis of the KCoPO₄ polymorphs. The title compound orders magnetically at T_N = 24.8 K.

Anomalous High-Temperature Superconductivity in YH6

Pressure-stabilized hydrides are a new rapidly growing class of high-temperature superconductors, which is believed to be described within the conventional phonon-mediated mechanism of coupling. Here, the synthesis of one of the best-known high-T_C superconductors-yttrium hexahydride I m 3 ¯ m -YH₆ is reported, which displays a superconducting transition at ≈224 K at 166 GPa. The extrapolated upper critical magnetic field B_c2 (0) of YH₆ is surprisingly high: 116-158 T, which is 2-2.5 times larger than the calculated value. A pronounced shift of T_C in yttrium deuteride YD₆ with the isotope coefficient 0.4 supports the phonon-assisted superconductivity. Current-voltage measurements show that the critical current I_C and its density J_C may exceed 1.75 A and 3500 A mm^-2 at 4 K, respectively, which is higher than that of the commercial superconductors, such as NbTi and YBCO. The results of superconducting density functional theory (SCDFT) and anharmonic calculations, together with anomalously high critical magnetic field, suggest notable departures of the superconducting properties from the conventional Migdal-Eliashberg and Bardeen-Cooper-Schrieffer theories, and presence of an additional mechanism of superconductivity.

Novel Strongly Correlated Europium Superhydrides

We conducted a joint experimental-theoretical investigation of the high-pressure chemistry of europium polyhydrides at pressures of 86-130 GPa. We discovered several novel magnetic Eu superhydrides stabilized by anharmonic effects: cubic EuH₉, hexagonal EuH₉, and an unexpected cubic (Pm3n) clathrate phase, Eu₈H₄₆. Monte Carlo simulations indicate that cubic EuH₉ has antiferromagnetic ordering with T_N of up to 24 K, whereas hexagonal EuH₉ and Pm3n-Eu₈H₄₆ possess ferromagnetic ordering with T_C = 137 and 336 K, respectively. The electron-phonon interaction is weak in all studied europium hydrides, and their magnetic ordering excludes s-wave superconductivity, except, perhaps, for distorted pseudohexagonal EuH₉. The equations of state predicted within the DFT+U approach (U - J were found within linear response theory) are in close agreement with the experimental data. This work shows the great influence of the atomic radius on symmetry-breaking distortions of the crystal structures of superhydrides and on their thermodynamic stability.

[Inflammatory infiltrates, vasa vasorum, and endothelial NO synthase in the wall of thoracic aortic aneurysm]

OBJECTIVE

To elucidate whether there is a relationship between inflammation of the wall of aortic aneurysm and the number of vasa vasorum in it.

MATERIAL AND METHODS

The investigation material was aortic aneurysm wall segments obtained during surgery. Among the patients, there were 20 men and 5 women. The patients' age ranged from 33 to 69 years. The investigation used monoclonal antibodies to macrophages (CD68), T cells (CD3, CD4, and CD8) and antibodies to von Willebrand factor, endothelial NO synthase, and alpha smooth muscle actin. A morphometric study was conducted.

RESULTS

Calculation of the number of vasa vasorum (including newly formed vessels) in the adventitia of aortic aneurysm revealed that there was a statistically significant difference between the number of vasa vasorum in patients with an active inflammatory response (Group 1) versus Group 2 patients with a moderate inflammatory process in the aneurysm wall (p≤0.05) and a statistically significant difference between Groups 1 and 3 (without inflammatory infiltrates) (p≤0.05). Endothelial vasa vasorum heterogeneity was found in case of an immune response to NO synthase. At the same time individual vasa vasorium did not contain NO synthase, this enzyme was identified in the endothelium in a number of nearby vessels.

CONCLUSION

The increase in the number of vasa vasorum in the aneurysm wall in patients with abundant inflammatory infiltrates is due to the fact that some of the inflammatory cytokines of T-cells and macrophages also contribute to angiogenesis.

[Prospects and peculiarities of the procedure of ultrasound ablation of subcutaneous veins of the lower limbs]

The last decade has seen active development of minimally invasive (endovenous) methods of surgical removal of lower limb varicose veins (LLVV); however, the problem of increasing efficacy of these methods and improving long-term results still remains of current importance. The authors of this work propose a method of ultrasound ablation of subcutaneous veins of lower extremities. Our experimental study was aimed at determining the pattern of venous wall damage after ultrasound exposure. Samples of segments of the trunk of the great saphenous vein (GSV) were divided into 5 groups: group 1 - the control group, group 2 - treatment with a sclerosant in the amount of 0.3 ml for 30 s, group 3 - treatment with ultrasound at a frequency of 26 kHz and amplitude 40 μm and 0.3-ml sclerosant for 30 s, group 4 - exposure to ultrasound at a frequency of 26 kHz and amplitude 40 μm and 0.3-ml sclerosant for 60 s, group 5 samples were exposed to ultrasound at 26 kHz and amplitude of 40 μm for 60 s. The results of analysing the histological sections of the samples of the 2nd and 3rd groups demonstrated that the degree of alteration in the GSV wall on combined exposure to ultrasound and a sclerosant was 4.5-fold higher as compared with treatment with a sclerosant solution alone. During ultrasound exposure, the maximum temperature of the venous wall of group 5 samples was by 20 °C higher than in samples of group 4. Analysing the histological sections demonstrated a similar pattern of structural alterations of the samples of group 4 and 5, thus suggesting a possibility of controlling the temperature of the venous wall during ultrasound ablation without changing quality of structural lesions. The obtained findings showed a possibility of initiating irreversible dystrophic alterations in the venous wall on exposure to ultrasound by means of combining the mechanisms of chemical, mechanical, and thermal ablation.

Hybrid PCL/CaCO3 scaffolds with capabilities of carrying biologically active molecules: Synthesis, loading and in vivo applications

Designing advanced biomaterials for tissue regeneration with drug delivery and release functionalities remains a challenge in regenerative medicine. In this research, we have developed novel composite scaffolds based on polymeric polycaprolactone fibers coated with porous calcium carbonate structures (PCL/CaCO₃) for tissue engineering and have shown their drug delivery and release in rats. In vivo biocompatibility tests of PCL/CaCO₃ scaffolds were complemented with in vivo drug release study, where tannic acid (TA) was used as a model drug. Release of TA from the scaffolds was realized by recrystallization of the porous vaterite phase of calcium carbonate into the crystalline calcite. Cell colonization and tissue vascularization as well as transplantability of developed PCL/CaCO₃+TA scaffolds were observed. Detailed study of scaffold transformations during 21-day implantation period was followed by scanning electron microscopy and X-ray diffraction studies before and after in vivo implantation. The presented results demonstrate that PCL/CaCO₃ scaffolds are attractive candidates for implants in bone regeneration and tissue engineering with a possibility of loading biologically active molecules and controlled release.

[Ultrasonic examination of the breast adipose grafts after mammoplasty]

AIM

To present the results of PRP-adipose grafts implanatation.

MATERIAL AND METHODS

The study included 25 patients after transplantation of autologous adipose tissue. Autotransplantation was performed to correct volume defects of breast and to restore lost volume after polyacrylamide gel removal in 4 patients; after mastectomy in 6 cases; after complicated replacement using silicone endoprostheses in 11 patients; after previous reduction in 2 cases; after augmentation mammoplasty in 2 cases. Mean age of patients was 42 years. Patients were divided into 2 groups. Group 1 included 12 patients in whom pure adipose tissue was transplanted. Group 2 consisted of 13 patients who received autologous fat with platelet-rich plasma (PRP).

RESULTS

Dynamic ultrasonic monitoring showed early resorption processes (liponecrosis foci) after autologous fat injection. Locally increased vascular pattern of breast tissue is an inflammatory sign requiring anti-inflammatory therapy. PRP-adipose grafts have improved outcomes.

[Expression of matrix metalloproteinases and their inhibitors in the internal carotid artery wall in pathological tortuosity]

The principal morphological sign of fibromuscular dysplasia in pathological tortuosity (PT) of the internal carotid artery (ICA) is the fragmentation of elastic fibers that are degraded by matrix metalloproteinases 2 and 9 (MMP-2, MMP-9). Nevertheless, the role of MMPs and their inhibitors in the pathogenesis of ICA PT remains completely unexplored.

AIM

to investigate the expression of elastin-degrading MMPs and their inhibitors in the wall of the ICA in PT by immunohistochemistry and confocal laser scanning microscopy.

METHODS

Immunohistochemical examination was made using antibodies to MMP-2, MMP-9 and their tissue inhibitors TIMP-1 and TIMP-2. MMP-9 and TIMP-1 levels were determined by confocal laser scanning microscopy.

RESULTS

Immunohistochemical examination revealed a statistically significant predominance of high concentrations of MMP-2 and MMP-9 and a low level of their inhibitor TIMP-1 in ICA PT, while simultaneous obvious accumulation of both markers was most often identified in the control group (p<0.05). Analysis of MMP-2/TIMP-2 and MMP-9/TIMP-2 ratios showed the prevalence of the simultaneously high expression of both proteins in ICA PT and in the control group too. The similar data were also obtained by confocal microscopy: the control group showed elevated MMP-9 and TIMP-1 expressions and the ICA PT control displayed a high proteinase and low inhibitor levels (p<0.05).

CONCLUSION

Elastic fiber fragmentation in ICA PT is due to imbalance between MMPs and their inhibitors; namely, the prevalence of MMP-2 and MMP-9 over their inhibitor TIMP-1, which leads to the degradation of extracellular matrix components, primarily elastin.

[Adhesion molecules and mononuclear cell subpopulations in the coronary and pulmonary arteries of patients with coronary heart disease]

Atherosclerosis is a multifactor disease, in which dysfunction of the endothelium leads to the emergence of its adhesion molecules.

OBJECTIVE

to investigate the expression of the endothelial adhesion molecules PECAM (CD31), ICAM, and VCAM, as well as adherent endothelial T cells and monocytes. The material examined was en face pulmonary and coronary artery samples taken during autopsies (10 men), and en face specimens obtained from the coronary artery fragments taken from coronary heart disease patients during endarterectomy (37 men). This investigation used antibodies to the adhesion molecules ICAM-1, VCAM-1, and PECAM and those to CD3, CD4, CD8 T-cells and CD68 monocytes.

RESULTS

The endothelial cells in the atherosclerotically intact coronary arteries had an elongated shape and were aligned along the blood flow. Those located above atheromas and fibroatheromas changed their shape from elongated to polygonal. Above the fatty streaks and atheromas, the reaction with antibodies to CD31 antigens became weaker at the edge of endothelial cells and disappeared in places. While the atherosclerotic process progressed, the reaction with the CD31 antigen at the edge of endothelial cells was similar in intensity to that on the surface of the endothelium. Adhesion of T cells and monocytes to the endothelium of coronary arteries increased as the atherosclerotic vascular process progressed. T cells and monocytes more often adhered to the endothelium at the sites where the endothelial cells contacted each other.

CONCLUSION

Heterogeneity was found in the endothelial cells: their shape, the expression of adhesion molecules, and the adhesion of lymphocytes and monocytes to them changed during the progression of the atherosclerotic process.

[The structure of the internal carotid artery wall in pathological tortuosity]

OBJECTIVE

to study a change in the content of main components of the internal carotid artery (ICA) wall in pathological tortuosity (PT) resulting from fibromuscular dysplasia, using immunohistochemistry and confocal laser scanning microscopy.

MATERIAL AND METHODS

Immunohistochemical (IHC) analysis using antibodies to elastin, collagen types I and III, and smooth muscle actin was made. The levels of elastin and matrix metalloproteinase 9 (MMP-9) were determined by confocal laser scanning microscopy. The relative area of expression and the area of co-location of these markers were measured.

RESULTS

IHC examination of the expression of elastin revealed that the patients with PT of ICA had its higher content than the controls, but they were observed to have fiber fragmentation. Comparison of collagen types I and III expressions showed no significant differences between the groups. The found significantly lower smooth muscle actin expression in the patients with PT of ICA than in the controls was suggestive of the decreased levels of smooth muscle cells. Confocal microscopy analysis showed high elastin and low MMP-9 expressions in the control group and, on the contrary, low elastin and high proteinase levels in the PT group (р<0.05).

CONCLUSION

One of the causes of PT is impairment in vascular elastic properties due to the destruction of elastic fibers and to their fragmentation, as well as to the decreased count of smooth muscle cells, which in turn causes enhanced MMP-9 activity and tissue matrix degradation.

[Surgical treatment for fibro-muscular dysplasia]

AIM

To present the results of surgical treatment of patients with fibro-muscular dysplasia.

MATERIAL AND METHODS

Our experience of treatment of 144 patients with fibro-muscular dysplasia is presented in the article. 118 (82%) patients suffered from stenoses, kinking and aneurysms of internal carotid arteries, 21 (14.5%) patients had lesion of renal arteries, 5 (3.5%) patients--azygous visceral arteries lesion. It was performed 157 reconstructive operations in the Department of cardiac surgery N(o)1 (aortic surgery) of acad. B.V. Petrovskiy Russian Research Center for Surgery for the period from 1993 to 2014. Clinical features of fibro-muscular dysplasia, surgical tactics and technique depending to the localization of lesion are described.

RESULTS

Immediate and remote surgical results were studied. There were no any severe intraoperative and immediate postoperative complications. Follow-up after carotid surgery was 104.49±68.68 months (6-247 months). Strokes were not observed. Hemodynamically insignificant re-stenoses were diagnosed in 7 (5.5%) cases. Mean follow-up after renal reconstructions was 139.24±63.96 months (28-239 months). Persistent blood pressure normalization was achieved in 11 (73.3%) cases. Patients with azygous visceral arteries dysplasia have been examined for the period of 103.4±69.6 months (35-205 months). There were no recurrent aneurysms and abdominal ischemia in the remote postoperative period. Hospital and remote mortality was absent. Based on own experience and colleagues' data we consider that surgical treatment of patients with some forms of fibro-muscular dysplasia provides satisfactory results if advisable strategy is selected.

[Sevoflurane optimal dosage estimation for myocardium pharmacological postconditioning: an experimental study]

We estimated the optimal dosage of inhalation anesthetic sevoflurane, for the maximum cardioprotective effect with minimal angioparalytic action. 25 pigs were included in this study, they were divided into 5 groups, depending on the sevoflurane dosage used for pharmacological postconditioning (PPC): control group - PPC has't been conducted, a group of PPC 0.5 - sevoflurane PPC in a dose of 0.5 V%, a group of PPC 1.0 - sevoflurane PPC in a dose of 1.0 V%, a group of PPC 1.5 - sevoflurane PPC in a dose of 1.5 V%, a group of PPC 2.0 - sevoflurane PPC in a dose of 2.0 V%, a group of PPC 2.5 - sevoflurane PPC in a dose of 2.5 V%. Ischemia was simulated by left coronary artery crossclamping. Further PPC was held according to the following Protocol: 20 min before left coronary artery clamp off and first 20 min of reperfusion sevoflurane was given into CPB circuit. Myocardial ischemia period was 60 min in all groups. It was found and experimentally proved that the optimal sevoflurane dosage for PPC is 2 V%

A comparative study of the aortic wall in patients with Marfan's syndrome and Erdheim's disease

The materiel of intraoperative biopsies (378) and autopsies was used to study the morphology of the aortic wall in patients with Marfan's syndrome (62) and Erdheim's disease (133). Histological, histochemical and electron microscopy research methods were employed with an assay of the results obtained. It has been demonstrated that in connective tissue dysplasia in the aorta, the histological structure of the intima undergoes substantial changes alongside the pathology of the tunica media. It is marked by the formation of a focal and diffuse thickening with the predominance of the interstitial substance, rich in glycosaminoglycans, and of a small amount of fibrous structures. The morphological signs of the impairment of endothelial permeability (vacuolisation of cytoplasm, thinning of its peripheral portions and basal membrane, expansion of intercellular fissures) are identifiabe, which leads to the disorder of aortic wall metabolism and early development of atherosclerosis. The changes in the intima together with the pathology of the tunica media ere predisposing factors of aneurysm formation, dissection and rupture of the aorta.

[Differential diagnosis of hepatocellular carcinoma using laser DNA-cytofluorometry]

Because of insufficient amount of material obtained in many cases of puncture biopsy, Differential diagnosis of hepatocellular carcinoma (HCC) with benign tumors and focal cirrhotic lesions of the liver is difficult. The study was aimed at development of additional criteria for HCC differential diagnosis of the basis of a comparison of morphological data (histological and cytological) with DNA content in the cells of focal lesion of the liver and is based on the research of biopsy material from 111 patients with focal liver lesions. Laser DNA flow cytometry (DNA-FCM) was carried out in 59 samples using laser flowing cytometer FACScan (Becton Dickinson, USA). The complex of three HCC histological criteria was established (trabecular histoarchitecture, increased nuclear-cytoplasmatic rate and nuclear crowding) for comparison with puncture biopsy of the liver (diagnostic efficiency 93.7%). Optimal quantitative parameters for HCC diagnosis were the following: reduction of the number of cells in a GO/1 phase of the cell cycle (< 77.5%), appearance of aneuploid clone of cell DNA index > 1.0 and decreased percent of binucleated cells (< 10%). Very high diagnostic specificity of the research was found (98.3%). Usage of quantitative parameters in the complex with histological criteria of HCC increased efficiency of the diagnosis up to 98%.

[Perioperative myocardial infarct during the surgical treatment of IHD]

Perioperative myocardial infarction is one of the most frequent causes of death in patients subjected to surgery for coronary disease. Study of the pathogenesis of this complication may become an approach to decreasing the postoperative mortality. Forty-seven case histories and autopsy protocols of patients who died after surgery on the coronary arteries and 241 intraoperative biopsy specimens of autovenous shunts are analyzed. The mechanisms underlying the cardiomyocyte necrosis in surgical treatment of coronary disease are based on various pathological processes, the leading of which is thrombosis of the shunts and coronary arteries. The principal factors were intraoperative ischemia of autovein endothelium and shunting of coronary artery with a narrow distal bed.

[The myocardial capillary endothelium in patients with coronary heart disease in aortocoronary bypass surgery with pharmacologic and hypothermal cardioplegia]

The time course of changes in the myocardial capillary endothelium was studied in 68 male patients with coronary heart disease (whose ages ranged from 29 to 62 years) at aortocoronary bypass surgery under drug-induced cold (DICCP) and thermal cardioplegia (TCP). As compared to DICCP, TCP was shown to have a more protective effect and preserves the ultrastructure of capillary endotheliocytes. Activated nonspecific pinocytosis and higher convectional transport through the transendothelial channels produce no significant microcirculatory and hemostatic effects in the postoperative period.

[Role of membrane protectors and antioxidants in the process of perfusion and preservation of donor lungs]

Comparative study of the effect of four perfusion and preservation solutions on lung function, conducted in experiments on 69 inbred dogs, revealed the following regular features. Euro-Collins and electrolyte solutions cause a marked increase of the capillary-hydrostatic pressure, a significant decrease of colloido-osmotic pressure of the plasma, and, as a result, reduction of the ient between them. This is manifested by edema of the lungs. The use of LPD solution is attended by moderate edema of the lungs in moderately increased capillary hydrostatic pressure and mildly reduced colloido-osmotic pressure of the plasma. Perfusion and preservation of the lungs with the LPD solution, containing membrane protectors and antioxidants, for 12 hours is marked by practically unchanged indices of capillary-hydrostatic pressure, plasma coloido-osmotic pressure, and the gradient between them. Edema of the lungs does not develop in this case.

[The quality of the preservation of lungs using different solutions (an experimental study)]

Effects of different perfusion conditions and storage of isolated dog lungs on the process of edema development were studied. Sixty-nine mongrel dogs were used in the study. In case of a 15 min perfusion via the pulmonary artery and 12 h storage lung condition depended mainly on the type of solution and addition of protective drugs to this solution. Euro-Collins and low-potassium electrolytic solution markedly increased capillary hydrostatic pressure and drastically reduced plasma colloid-osmotic pressure. As a result filtration coefficient increased and as soon as an hour after reperfusion onset a marked pulmonary edema developed. Use of LPD solution without drugs added for 2.5 h reperfusion was associated with a moderate increase of capillary hydrostatic pressure and negligible decrease of plasma colloid-osmotic pressure. If the reperfusion were longer plasma colloid-osmotic pressure reduced, this leading to development of moderate pulmonary edema. A 15 min lung perfusion via the pulmonary artery and 12 h storage at 1 degree C in LPD solution with membrane protectors and antioxidants was associated with virtually unchanged capillary hydrostatic pressure, plasma colloid-osmotic pressure, and filtration coefficient and, hence, no pulmonary edema.

[Ultrastructure of myocardial capillaries in chronic ischemic heart disease]

Intraoperative myocardial biopsy specimens taken from 50 patients with coronary heart disease were studied to examine ultrastructure of myocardial capillaries. It was found that this disease was characterized by abundant myocardial capillaries with a narrowed lumen. Quantitative stereological analysis indicated that the ultrastructure of the capillaries with narrowed lumen was not substantially different from that of open capillaries. The findings showed that the narrowed capillaries to be reserve and capable of providing an adequate blood supply of cardiomyocytes after aortocoronary bypass surgery.

[Effect of axoplasmic transport blocking and denervation on the activity and isomolecular spectra of some dehydrogenases in rat muscles]

Changes in the total activity and in the activity of isoenzyme forms of lactate dehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.37) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) are found in rat musculus gastrocnemius two weeks after blocking axoplasmic transport evoked by the application of 0.05 M colchicine solution to the ischiatic nerve. They are identical to those observed in surgical denervation. The changes in the isomolecular forms of the enzyme permit considering that the cell metabolism is affected by the axoplasmatic transport.

[Effect of axoplasmic flow elimination and denervation on the contents of protein, nucleic acids and glycogen in rat muscle]

Disturbance of the axoplasmic flow was evoked by ligation of the sciatic nerve with a silk thread moistened with 0.05 solution of colchicine (exposition for 30 s). No intoxication was observed in the animals, the motor function of the operated extremety was preserved. Two weeks after elimination of the axoplasmic flow practically the same changes in the content of contractile and sarcoplasmic proteins, glycogen, DNA and RNA were observed in musculi gastrocnemius as with surgical denervation. The data obtained evidence for an important role of the axoplasmic flow to maintain the normal metabolism in muscles.

[Action of acid cathepsins on the myosin and sarcoplasmic proteins of normal and denervated rat muscles]

The activity of acid cathepsins in extracts of the healthy and denervated rat muscles was determined, using the proper and homologous sarcoplasmic proteins and myosin as substrates. Splitting of the sarcoplasmic proteins produces a 50% increase and that of myosin produces a 110% increase in the activity of acid cathepsins of the denervated muscles as compared to that of healthy ones. Substrates isolated from the healthy and denervated muscles are splitted by acid cathepsins with the same intensity.