[Diagnosis and treatment of kidney damage following stab and blunt abdominal injuries]. / Diagnostika i lechenie povrezhdenii pochek pri zakrytykh travmakh i koloto-rezanykh raneniyakh zhivota.

OBJECTIVE: To improve treatment outcomes in victims with kidney damage following blunt and stab abdominal trauma by using of minimally invasive methods of diagnosis and treatment. MATERIAL AND METHODS: About 1.2-3.5% of all victims arrived to the Dzhanelidze St. Petersburg Research Institute for Emergency Care have kidney injuries. We analyzed the results of treatment of 117 patients with isolated and combined blunt and stab abdominal injuries. The retrospective (2014-2017) group included 62 victims, and the prospective (2018-2021) group enrolled 55 patients who were treated according to the new algorithm. This algorithm included non-surgical and minimally invasive management for patients with systolic blood pressure >90 mm Hg after contrast-enhanced CT. Angiography with selective embolization was required for ongoing bleeding. We analyzed incidence of open interventions, organ-sparing procedures, complications, duration of treatment and mortality. Between-group differences were assessed using the χ2 test and Student's test. RESULTS: In both groups, kidney damage in most victims with abdominal trauma was due to road accident and catatrauma. Most patients had combined abdominal injuries, mainly in combination with head and chest lesions. Severity of injuries and clinical condition were similar in both groups. In the retrospective group, there were 9 laparotomies with nephrectomy. Nephrorraphy was performed in 8 cases, kidney vessel suture - in 4 patietns. In the prospective group, nephrectomy was performed in 3 patients with unstable hemodynamics and injuries AAST grade V. Nephrorraphy was performed in 4 victims. In one case, vascular suture was applied for tangential vein damage. All laparoscopies in both groups were diagnostic without nephrectomy. We used non-surgical treatment in 34 patients of the prospective group. One patient underwent angiography and selective embolization of renal artery branches. There were no significant between-group differences in the incidence of infectious and non-infectious complications. Mortality rate was 30.6% (n=19) and 27.3% (n=15) in the retrospective and prospective groups, respectively. CONCLUSION: The proposed algorithm for kidney injury made it possible to reduce the incidence of laparoscopies and laparotomies by 2 times, preserve the damaged kidney in 94.5% of cases and avoid invasive treatment in 62% of victims.

[Primary retrograde distal access for endovascular interventions in patients with lower limb ischemia]. / Pervichnyi retrogradnyi distal'nyi dostup pri endovaskulyarnykh vmeshatel'stvakh u patsientov s ishemiei nizhnikh konechnostei.

OBJECTIVE: To evaluate safety and technical efficiency of primary retrograde distal access for endovascular interventions in patients with lower limb ischemia. MATERIAL AND METHODS: A prospective analysis included 25 endovascular procedures via primary retrograde distal access in 23 patients with chronic obliterating diseases of lower limb arteries. Occlusive lesion of femoral-popliteal segment was observed in 68% of cases, occlusion of at least one tibial artery was also found in 68% of cases. In 44% of cases, occlusive lesion was localized at several levels. Percutaneous intervention via anterior tibial artery or dorsalis pedis artery was performed in 68% of cases, posterior tibial artery - 24% of cases, peroneal artery - 8% of cases. We used 2 accesses in 92% of cases (the main one for intervention and additional one for angiography). In 8% of cases, intervention was carried out through a single access. Angiosome artery was punctured in 65% of cases. The only patent tibial vessel was used in 20% of cases. In 24% of cases, we performed antegrade recanalization of 'adjacent' tibial artery via distal access. RESULTS: Primary retrograde distal access was successfully performed in 100% of cases. Retrograde revascularization was not successful in all cases (successful recanalization rate 96%, retrograde intervention rate - 92%). Femoral access was performed in 8% of cases. Antegrade blood flow through at least one tibial artery was restored in all cases. Direct revascularization of the affected angiosome was performed in 15 patients with foot necrosis, indirect revascularization through collaterals - in 5 patients. Local complications of surgical access occurred in 12% of cases. CONCLUSION: Endovascular revascularization via primary retrograde distal access was technically effective in most cases. There were no complications with systemic consequences.

Effect of DMSO, urea and ethanol on hydration of stratum corneum model membrane based on short-chain length ceramide [AP].

Hydration of oriented multilamellar membrane based on ceramide [AP] in the DMSO, urea and ethanol aqueous solutions at various solute concentrations was investigated by neutron diffraction. Neither urea nor DMSO influence the repeat distance of the membrane and internal structure of bilayer at their mole concentration of up to 0.15 and 0.10, respectively. The d-spacing reduction effect of both compounds was observed at their concentrations of 0.2 for urea and 0.2 and 0.4 for DMSO. Compared to hydration in the pure water, both urea and DMSO slow down the swelling process, and this slowdown is more pronounced with increasing in their concentration. At concentration of 0.2, urea and DMSO induce the slight phase separation of the fully hydrated samples; at the highest used concentration of 0.6, DMSO induces the strong time-depend separation of the sample probably due to fluidization of lipid bilayers. Ethanol at a used molar concentration of 0.03 leads to dissolution of the sample.

[Assessment of functional state of microcirculatory bed of the foot in patients with lower limb critical ischaemia]. / Otsenka funktsional'nogo sostoianiia mikrotsirkuliatornogo rusla stopy u bol'nykh s kriticheskoi ishemiei nizhnikh konechnostei.

The authors assessed perfusion of the foot in patients presenting with lower limb critical ischaemia before and after endovascular revascularization, as well as analysed the interrelationship between the change of perfusion and the clinical result of treatment. The study includes a total of 15 patients presenting with ulcerative-necrotic defects of the foot. All patients underwent study of 2D-perfusion of the foot before and after the endovascular intervention. The '2D-perfusion' package was used within the framework of an angiographic examination, and required neither increase in the volume of the contrast medium nor radiation load. Four parameters of perfusion were evaluated: the time of ingress, the time of reaching the peak value, the peak value and the area under the curve. After the intervention, as compared with the baseline values there were statistically significant differences by the time of ingress (a 2.4-fold decrease; p<0.0001), the peak value (a 1.8-fold increase; p<0.0001) and the area under the curve (a 2.4-fold increase; p<0.0001). No statistically significant differences were revealed while comparing the time of reaching the peak value before and after the intervention (p=0.767). Trophic defects healed in 11 (73.3%) patients, and in 4 (26.7%) patients the process of healing continued with positive dynamics at the check-up examination. Hence, our first experience of using the assessment of 2D-perfusion demonstrates simplicity of the method with no increase of the radiation load and the dose of the contrast medium. The method makes it possible to obtain important data about the state of microcirculation of the foot in patients with lower limb critical ischaemia, to evaluate alterations after the endovascular intervention. Improvement of the parameters of perfusion is associated with a good clinical outcome.

Short periodicity phase based on ceramide [AP] in the model lipid membranes of stratum corneum does not change during hydration.

Small angle X-ray scattering technique was used to determine electron density profiles of short periodicity phase in the model lipid membranes of stratum corneum at different pH. Basic quaternary system was prepared as used previously in the neutron experiments at partial hydration. It was shown that electron density profiles of partially hydrated and fully hydrated model lipid membranes with four basic components were quite similar and demonstrated almost no interbilayer water.

Application of small-angle X-ray scattering to the characterization and quantification of the drug transport nanosystem based on the soybean phosphatidylcholine.

Phospholipid transport nanosystem (PTNS) for drug delivery is based on soybean phosphatidylcholine. The morphology of PTNS is investigated by means of small-angle X-ray scattering. The obtained results allow one to answer the key question from the viewpoint of organization of drug incorporation whether the PTNS nanoparticles have a structure of micelles or vesicles. It is demonstrated that PTNS is a vesicular system with an average vesicle radius of 160 ± 2Å.

[Remote results of endovascular revascularization in patients with lower limb critical ischaemia (LLCI) kept on chronic haemodialysis]. / Otdalennye rezul'taty éndovaskuliarnoi revaskuliarizatsii u bol'nykh s kriticheskoi ishemiei nizhnikh konechnostei, nakhodiashchikhsia na khronicheskom gemodialize.

The study was aimed at assessing remote results of endovascular treatment of patients presenting with lower limb critical ischaemia (LLCI) and kept on chronic haemodialysis. We retrospectively analysed the results of endovascular interventions in a total of 16 patients with ischaemic defects of the foot being on chronic haemodialysis, performed from 2001 to 2012 at the Department of Roentgenosurgical Methods of Diagnosis and Treatment of the St. Petersburg Scientific Research Institute for Emergency Ambulance Care named after I.I. Dzhanelidze. The patients' age varied from 39 to 75 years (mean 56.2±12.8 years). There were 11 (68.7%) men and 5 (31.3%) women. Ten patients (62.5%) suffered from diabetes mellitus. Of the ten diabetic patients, nine (56.2%) received insulin. A total of 21 endovascular interventions were performed on 16 extremities. The obtained findings were statistically processed by means of the Kaplan-Meier method. During follow up, LLCI relapses were observed in eleven (68.7%) patients, amputation of the femur was performed in eight (50%) patients, and five (31.2%) patients survived without major amputation. One year and two years after intervention, the probability of LLCI relapse absence amounted to 37.5 and 30%, respectively, that of major amputation - to 67.5 and 24.1%, survival without major amputation - to 50 and 17.9%, respectively. Patients with LLCI kept on chronic haemodialysis belong to a group of high risk of limb loss and a lethal outcome within 2 years after angioplasty.

[Angiographic characteristics of the lesion, influencing the choice to perform either direct or indirect endovascular revascularization for critical ischaemia of the lower limbs].

AIM: to determine which angiographic characteristics of a lesion of lower limb arteries are independent predictors of the possibility to re-establish the direct blood flow along the angiosomic (in relation to the trophic defect) artery. MATERIAL AND METHODS: we carried out a retrospective analysis of angiograms of 192 patients with degree IV peripheral arterial disease according to A.V. Pokrovky's classification, with restored free blood flow to the foot at least along one femoral artery by means of balloon angioplasty. All patients were subdivided into two groups: the group of direct revascularization (84 patients) and the group of indirect revascularization (108 patients). The compared groups reliably did not differ by the clinical characteristics and the stage of the trophic lesion (male gender, prevalence of diabetes mellitus and mean age amounted to: 45%, 73% and 71 years versus 39%, 77% and 69 years, respectively). However, in the group of direct revascularization more frequently were encountered lesions of the toes (75% vs 55%, p = 0.005), while in the group of indirect revascularization prevailing were lesions of the heel region (7% vs 29%, p=0.0002). RESULTS: the statistical analysis showed that independent predictors for a possibility of performing direct revascularization were as follows: total occlusion of the angiosomic artery on the foot (risk ratio (95% CI) = 0.10 (0.03-0.31), p =0.0001), blind (without stump) occlusion in the site of the origin of the angiosomic artery on the crus or foot (risk ratio (95% CI)=0.41 (0.19-0.90, p=0.03), and total occlusion of the trifurcation of the popliteal artery (risk ratio (95% CI) = 028 (0.09-0.81), p=0.02). CONCLUSION: in the presence of the above enumerated angiographic characteristics of the lesions of lower limb arteries it is appropriate to initially consider a possibility of performing indirect revascularization.

Investigation of stratum corneum lipid model membranes with free fatty acid composition by neutron diffraction.

The outermost epidermal layer, the stratum corneum (SC), is the main skin barrier. Studies of SC model systems enable characterization of the influence of individual lipids on the organization of the SC lipid matrix, which is the main pathway of water through the skin. This work presents a neutron diffraction study of the SC model membranes based on short-chain ceramide 6 with nearly realistic composition of free fatty acids (FFA) at physiological temperature of the SC. The influence of FFA and the effect of cholesterol-cholesterol sulfate substitution on the structure and hydration of the SC model membranes are described. The structure of the SC membrane with FFA is close to the structure of the earlier studied SC membrane based on short-chain palmitic acid (PA) and does not vary significantly under changes of the ratio of the main membrane components. FFA accelerates membrane swelling at the same low level of hydration of both PA- and FFA-containing membranes. The substitution of cholesterol sulfate by cholesterol in the membrane composition decreases membrane swelling and leads to phase separation in the model system.

[Transition processes in Stratum corneum model lipid membranes with a mixture of free fatty acids].

The hydration of model membranes based on ceramide 6 with a mixture of free fatty acids the most commonly encountered the native lipid matrix of Stratum corneum, the outermost layer of the mammalian skin has been studied by neutron diffraction. Membrane hydration with water vapour at a temperature of 25 degrees C is characterized by a small increase in the repeat distance delta d0 = 1.0 A, which is comparable with membrane swelling in the presence of excess water. The kinetics changes in the repeat distance, connected with an increase of the water layer between bilayers during hydration, and water exchange during the processes of hydration and H-D isotopic substitution consists of a fast initial and a subsequent slow stage and is well described by exponential with two characteristic times lying in the range from a few tens of minutes to several hundreds of minutes. During hydration at a temperature of 57 degrees C, the repeat distance increases by delta d0 = 1.6 A, after which the membrane irreversibly separates into two phases. One of the phases is formed mainly by long-chain free fatty acids and is characterized by a large decrease in the repeat distance delta d(ph) = 8.3 A on dehydration. The investigation of the structure of model membranes in the temperature range 20-72 degrees C indicated that the system with 20% (w) of cholesterol in the range of 63-67 degrees C undergoes a structural phase transition caused by the melting of hydrocarbon chains of lipids. In the system with a smaller content of cholesterol, no phase transition was observed up to a temperature of 72 degrees C.

[Structural organization of the phospholipid constituent of cell membranes from Streptomyces hygroscopicus, as determined from neutron diffraction data].

The nanoparameters of the membrane from actinobacteria have been determined by the method of neutron diffraction on multilamellar lipid membranes. It was found that the repeat distance of a partly hydrated membrane formed from the phosphohpid fraction of Streptomyces hygroscopicus (S. hygroscopicus) is 85.8 +/- 0.5 A at T = 20 degrees C and decreases to 83.5 +/- 0.5 A at T = 40 degrees C. Some lipids are not incorporated into the bilayer and form the liquid micellar phase with micelles of size 54.2 +/- 0.2 A.

Properties of ceramides and their impact on the stratum corneum structure. Part 2: stratum corneum lipid model systems.

The stratum corneum (SC) represents the outermost layer of the mammalian skin, exhibits the main skin barrier and plays an important role in the water penetration pathway through the SC. Knowing the structure and properties of the SC at the molecular level is essential for studying drug penetration through the SC and for the development of new dermal drug delivery systems. Therefore, research interest is focused on the SC lipid matrix and on water diffusion through it. Thus, the ultimate aim is to design a lipid mixture that mimics the barrier properties of the human SC to a high extent and that can substitute the SC in drug delivery systems. This review summarizes various studies performed on either isolated animal or human ceramide based SC model systems, coming to the result that using synthetic lipids with a well-defined architecture allows good extrapolation to the in vivo situation. This review is the continuation of part 1 that is focused on a detailed description of the thermotropic and/or lyotropic phase behaviour of single ceramide types obtained by various experimental techniques. The objective of part 2 is to reflect the numerous studies on SC lipid model systems, namely binary, ternary and multicomponent systems, during the last decade. In this context, neutron diffraction as a prospective tool for analyzing the internal membrane structure is addressed in particular. Based on these new insights, current SC models are presented, whose validations are still under discussion. A profound knowledge about SC lipid organization at the molecular level is still missing.

Fatty acid interdigitation in stratum corneum model membranes: a neutron diffraction study.

The influence of the chain length of the free fatty acid (FFA) in a stratum corneum (SC) lipid model membrane composed of N-(alpha-hydroxyoctadecanoyl)-phytosphingosine (CER [AP]), cholesterol (Ch), FFA and cholesterol sulphate (ChS) was investigated by neutron diffraction. The internal nanostructure of the SC lipid membrane in addition to the water distribution function was determined via calculation of the neutron scattering length density profile (Fourier profile). The Fourier profiles of the studied SC model membranes revealed that such membranes have a repeat distance approximately equal to the membrane thickness. Increasing the chain length of the FFA in the CER[AP] based model membrane did not cause an alteration of the internal nanostructure but led to a decrease in the membrane repeat distance from 45.6 angstroms (palmitic acid, C16:0) to 43.7 angstroms (cerotic acid, C26:0) due to a partial interdigitation of the FFA chains. Ceramide [AP] forces the long chain fatty acids to incorporate into the unchanged spacing of the bilayer, thereby obligating the FFA protrude partly through opposing leaflet. Furthermore, the longer chained free fatty acids tend to form a new separate so-called "fatty acid rich phase". Therefore, the elongation of the chain length of the FFA decreases the solubility of the FFA in the SC model membrane based on CER[AP].

What can we learn about the lipid vesicle structure from the small-angle neutron scattering experiment?

Small-angle neutron scattering (SANS) on the unilamellar vesicle (ULV) populations (diameter 500 and 1,000 A) in D2O was used to characterize lipid vesicles from dimyristoylphosphatidylcholine (DMPC) at three phases: gel Lbeta', ripple Pbeta' and liquid Lalpha. Parameters of vesicle populations and internal structure of the DMPC bilayer were characterized on the basis of the separated form factor (SFF) model. Vesicle shape changes from nearly spherical in the Lalpha phase to elliptical in the Pbeta' and Lbeta' phases. This is true for vesicles prepared via extrusion through pores with the diameter 500 A. Parameters of the internal bilayer structure (thickness of the membrane and the hydrophobic core, hydration and the surface area of the lipid molecule) were determined on the basis of the hydrophobic-hydrophilic (HH) approximation of neutron scattering length density across the bilayer rhox and of the step function (SF) approximation of rhox. DMPC membrane thickness in the Lalpha phase (T = 30 degrees C) demonstrates a dependence on the membrane curvature for extruded vesicles. Prepared via extrusion through 500 A diameter pores, vesicle population in the Lalpha phase has the following characteristics: average value of minor semi-axis 266 +/- 2 A, ellipse eccentricity 1.11 +/- 0.02, polydispersity 26%, thickness of the membrane 48.9 +/- 0.2 A and of the hydrophobic core 19.9 +/- 0.4 A, surface area 60.7 +/- 0.5 A2 and number of water molecules 12.8 +/- 0.3 per DMPC molecule. Vesicles prepared via extrusion through pores with the diameter 1,000 A have polydispersity of 48% and membrane thickness of 45.5 +/- 0.6 A in the Lalpha phase. SF approximation was used to describe the DMPC membrane structure in Lbeta' (T = 10 degrees C) and Pbeta' (T = 20 degrees C) phases. Extruded DMPC vesicles in D2O have membrane thickness of 49.6 +/- 0.5 A in the Lbeta' phase and 48.3 +/- 0.6 A in the Pbeta' phase. The dependence of the DMPC membrane thickness on temperature was restored from the SANS experiment.

Influence of phytosphingosine-type ceramides on the structure of DMPC membrane.

The present paper describes the influence of the ceramides with phytosphingosine base, N-stearoylphytosphingosine (Cer[NP]) and alpha-hydroxy-N-stearoylphytosphingosine (Cer[AP]), on the structure and properties of multilamellar (MLVs) and unilamellar vesicles (ULVs) of dimyristoylphosphatidylcholine (DMPC). The lamellar repeat distance, D, has been measured at various temperatures using small angle X-ray diffraction. The incorporation of ceramides into the DMPC membrane causes larger D compared to pure DMPC membrane. For both ceramide types, at 32 degrees C, there is a linear relationship between the D value and the ceramide concentration. However, there is no such dependence at 13 or 60 degrees C. Unlike Cer[AP], Cer[NP] induces a new phase with a repeat distance of 38.5A. The membrane thickness and the vesicle radius of ULVs in water and in sucrose solution were calculated from small angle neutron scattering curves. Phytosphingosine ceramides increase both the membrane thickness and the radius in comparison to pure DMPC ULVs. The stability of ULVs in time was studied by dynamic light scattering. Both ceramides induce an aggregation of the ULVs into micrometer sized non-multilamellar structures in pure water. Presence of sucrose in the environment averts the vesicle aggregation.

New insights into the structure and hydration of a stratum corneum lipid model membrane by neutron diffraction.

The structure and hydration of a stratum corneum (SC) lipid model membrane composed of N-(alpha-hydroxyoctadecanoyl)-phytosphingosine (CER6)/cholesterol (Ch)/palmitic acid (PA)/cholesterol sulfate (ChS) were characterized by neutron diffraction. The neutron scattering length density across the SC lipid model membrane was calculated from measured diffraction peak intensities. The internal membrane structure and water distribution function across the bilayer were determined. The low hydration of the intermembrane space is a major feature of the SC lipid model membrane. The thickness of the water layer in the SC lipid model membrane is about 1 A at full hydration. For the composition 55% CER6/25% Ch/15% PA/5% ChS, in a partly dehydrated state (60% humidity) and at 32 degrees C, the lamellar repeat distance and the membrane thickness have the same value of 45.6 A . The hydrophobic region of the membrane has a thickness of 31.2 A . A decrease of the Ch content increases the membrane thickness. The water diffusion through the SC lipid model multilamellar membrane is a considerably slow process relative to that through phospholipid membranes. In excess water, the membrane hydration follows an exponential law with two characteristic times of 93 and 44 min. At 81 degrees C and 97% humidity, the membrane separates into two phases with repeat distances of 45.8 and 40.5 A . Possible conformations of CER6 molecules in the dry and hydrated multilayers are discussed.

Properties of ternary phospholipid/dimethyl sulfoxide/water systems at low temperatures.

X-ray diffraction, neutron diffraction and differential scanning calorimetry were used to investigate phase transitions in the ternary system phospholipid/dimethyl sulfoxide (DMSO)/water under cooling for three homologous phospholipids: dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC), and distearoylphosphatidylcholine (DSPC). Below the temperature of ice formation from -40 to -113 degrees C, a new lamellar phase of DPPC and DSPC was found at and above a DMSO molar fraction of X(DMSO) = 0.05. Below X(DMSO) = 0.05 only a single dehydrated Lc-phase exists after ice formation. The new phase has an increased membrane repeat distance and coexists with a dehydrated Lc-phase. DPPC with a DMSO molar fraction of X(DMSO) = 0.07 shows a membrane repeat distance of the new phase of d = 6.61 +/- 0.03 nm. The value of d increases at the increase of X(DMSO). The new phase was not observed in the ternary system with DMPC. No correlation between the new phase and the glass transition of bound water in the intermembrane space was detected. The new phase was detected only in the systems with excess of water. The creation of the new phase demonstrates the specific DMSO interaction with hydrocarbon chains.

Does sucrose influence the properties of DMPC vesicles?

Small-angle neutron and X-ray scattering, dynamic light scattering, X-ray diffraction coupled with differential scanning calorimetry, and Raman spectroscopy were applied to investigate unilamellar (ULVs) and multilamellar (MLVs) dimyristoylphosphatidylcholine (DMPC) vesicles in aqueous sucrose solutions with sucrose concentrations from 0 to 60% w/w. In case of ULVs, the addition of sucrose decreases the polydispersity of vesicle population. A minimum value of polydispersity was found at 20% sucrose. For sucrose concentration from 0 to 35% oligolamellar vesicles in the ULV population have a minimum presence. Vesicles with 5-10% sucrose exhibit the best stability in time. For the case of MLVs, sucrose influences the temperature of the phase transitions, but the internal membrane structure remains unchanged.