Hyperglycemia exacerbates ischemic stroke not through increased generation of hydrogen peroxide

Diabetes is one of the significant risk factors for ischemic stroke. Hyperglycemia exacerbates the pathogenesis of stroke, leading to more extensive cerebral damage and, as a result, to more severe consequences. However, the mechanism whereby the hyperglycemic status in diabetes affects biochemical processes during the development of ischemic injury is still not fully understood. In the present work, we record for the first time the real-time dynamics of H2O2 in the matrix of neuronal mitochondria in vitro in culture and in vivo in the brain tissues of rats during development of ischemic stroke under conditions of hyperglycemia and normal glucose levels. To accomplish this, we used a highly sensitive HyPer7 biosensor and a fiber-optic interface technology. We demonstrated that a high glycemic status does not affect the generation of H2O2 in the tissues of the ischemic core, while significantly exacerbating the consequences of pathogenesis. For the first time using Raman microspectroscopy approach, we have shown how a sharp increase in the blood glucose level increases the relative amount of reduced cytochromes in the mitochondrial electron transport chain in neurons under normal conditions in awake mice.

Sub-cycle pulse revealed with carrier-envelope phase control of soliton self-compression in anti-resonant hollow-core fiber

The influence of the carrier-envelope phase (CEP) of a pump pulse on the multioctave supercontinuum (SC) generation in a gas-filled anti-resonant hollow-core fiber (AR HCF) by soliton self-compression (SSC) has been explored. We have shown an octave-wide third harmonic generation (THG) in the visible-to-near-infrared range during the pulse compression down to a sub-cycle duration. The CEP of a multi-cycle pump pulse provides control of interference between the third harmonic (TH) and the SC that indicates the coherent synthesis of a sub-cycle pulse with a duration of about 0.4 optical cycles and a peak power of more than 2 GW at the fiber output.

Real-time fiber-optic recording of acute-ischemic-stroke signatures

We present an experimental framework and methodology for in vivo studies on rat stroke models that enable a real-time fiber-optic recording of stroke-induced hydrogen peroxide and pH transients in ischemia-affected brain areas. Arrays of reconnectable implantable fiber probes combined with advanced optogenetic fluorescent protein sensors are shown to enable a quantitative multisite time-resolved study of oxidative-stress and acidosis buildup dynamics as the key markers, correlates and possible drivers of ischemic stroke. The fiber probes designed for this work provide a wavelength-multiplex forward-propagation channel for a spatially localized, dual-pathway excitation of genetically encoded fluorescence-protein sensors along with a back-propagation channel for the fluorescence return from optically driven fluorescence sensors. We show that the spectral analysis of the fiber-probe-collected fluorescence return provides means for a high-fidelity autofluorescence background subtraction, thus enhancing the sensitivity of real-time detection of stroke-induced transients and significantly reducing measurement uncertainties in in vivo acute-stroke studies as inherently statistical experiments operating with outcomes of multiply repeated measurements on large populations of individually variable animal stroke models.

Eliminating Orbital Selectivity from the Metal-Insulator Transition by Strong Magnetic Fluctuations

The orbital-selective electronic behavior is one of the most remarkable manifestations of strong electronic correlations in multiorbital systems. A prominent example is the orbital-selective Mott transition (OSMT), which is characterized by the coexistence of localized electrons in some orbitals, and itinerant electrons in other orbitals. The state-of-the-art theoretical description of the OSMT in two- and three-dimensional systems is based on local nonperturbative approximations to electronic correlations provided by dynamical mean-field theory or slave spin method. In this work we go beyond this local picture and focus on the effect of spatial collective electronic fluctuations on the OSMT. To this aim, we consider a half-filled Hubbard-Kanamori model on a cubic lattice with two orbitals that have different bandwidths. We show that strong magnetic fluctuations that are inherent in this system prevent the OSMT and favor the Néel transition that occurs at the same critical temperature for both orbitals.

Orbital Isotropy of Magnetic Fluctuations in Correlated Electron Materials Induced by Hund's Exchange Coupling

Characterizing nonlocal magnetic fluctuations in materials with strong electronic Coulomb interactions remains one of the major outstanding challenges of modern condensed matter theory. In this Letter, we address the spatial symmetry and orbital structure of magnetic fluctuations in perovskite materials. To this aim, we develop a consistent multiorbital diagrammatic extension of dynamical mean-field theory, which we apply to an anisotropic three-orbital model of cubic t_{2g} symmetry. We find that the form of spatial spin fluctuations is governed by the local Hund's coupling. For small values of the coupling, magnetic fluctuations are anisotropic in orbital space, which reflects the symmetry of the considered t_{2g} model. Large Hund's coupling enhances collective spin excitations, which mixes orbital and spatial degrees of freedom, and magnetic fluctuations become orbitally isotropic. Remarkably, this effect can be seen only in two-particle quantities; single-particle observables remain anisotropic for any value of the Hund's coupling. Importantly, we find that the orbital isotropy can be induced both at half filling and for the case of four electrons per lattice site, where the magnetic instability is associated with different, antiferromagnetic and ferromagnetic, modes, respectively.

In vivo dynamics of acidosis and oxidative stress in the acute phase of an ischemic stroke in a rodent model

Ischemic cerebral stroke is one of the leading causes of death and disability in humans. However, molecular processes underlying the development of this pathology remain poorly understood. There are major gaps in our understanding of metabolic changes that occur in the brain tissue during the early stages of ischemia and reperfusion. In particular, it is generally accepted that both ischemia (I) and reperfusion (R) generate reactive oxygen species (ROS) that cause oxidative stress which is one of the main drivers of the pathology, although ROS generation during I/R was never demonstrated in vivo due to the lack of suitable methods. In the present study, we record for the first time the dynamics of intracellular pH and H2O2 during I/R in cultured neurons and during experimental stroke in rats using the latest generation of genetically encoded biosensors SypHer3s and HyPer7. We detect a buildup of powerful acidosis in the brain tissue that overlaps with the ischemic core from the first seconds of pathogenesis. At the same time, no significant H2O2 generation was found in the acute phase of ischemia/reperfusion. HyPer7 oxidation in the brain was detected only 24 h later. Comparison of in vivo experiments with studies on cultured neurons under I/R demonstrates that the dynamics of metabolic processes in these models significantly differ, suggesting that a cell culture is a poor predictor of metabolic events in vivo.

Direct Observation of Incommensurate-Commensurate Transition in Graphene-hBN Heterostructures via Optical Second Harmonic Generation

Commensurability effects play a crucial role in the formation of electronic properties of novel layered heterostructures. The interest in these moiré superstructures has increased tremendously since the recent observation of a superconducting state (Nature 2018, 556, 43-50) and metal-insulator transition (Nature 2018, 556, 80-84) in twisted bilayer graphene. In this regard, a straightforward and efficient experimental technique for detection of the alignment of layered materials is desired. In this work, we use optical second harmonic generation, which is sensitive to the inversion symmetry breaking, to investigate the alignment of graphene/hexagonal boron nitride heterostructures. To achieve that, we activate a commensurate-incommensurate phase transition by a thermal annealing of the sample. We find that this structural change in the system can be directly observed via a strong modification of a nonlinear optical signal. Unambiguous interpretation of obtained results reveals the potential of a second harmonic generation technique for probing of structural changes in layered systems.

Chirp-controlled high-harmonic and attosecond-pulse generation via coherent-wake plasma emission driven by mid-infrared laser pulses

Coherent-wake plasma emission induced by ultrashort mid-infrared laser pulses on a solid target is shown to give rise to high-brightness, high-order harmonic radiation, offering a promising source of attosecond pulses and a probe for ultrafast subrelativistic plasma dynamics. With 80-fs, 0.2-TW pulses of 3.9-μm radiation used as a driver, optical harmonics up to the 34th order are detected, with their spectra stretching from the mid-infrared region to the extreme ultraviolet region. The harmonic spectrum is found to be highly sensitive to the chirp of the driver. Particle-in-cell analysis of this effect suggests, in agreement with the generic scenario of coherent-wake emission, that optical harmonics are radiated as trains of extremely short, attosecond ultraviolet pulses with a pulse-to-pulse interval varying over the pulse train. A positive chirp of the driver pulse can partially compensate for this variation in the interpulse separation, allowing harmonics of the highest orders to be generated in the plasma emission spectrum.

Heisenberg-exchange-free nanoskyrmion mosaic

Isotropic Heisenberg exchange naturally appears as the main interaction in magnetism, usually favouring long-range spin-ordered phases. The anisotropic Dzyaloshinskii-Moriya interaction arises from relativistic corrections and is a priori much weaker, even though it may sufficiently compete with the isotropic one to yield new spin textures. In this work, we challenge this well-established paradigm, and propose to explore a Heisenberg-exchange-free magnetic world. In this case, the Dzyaloshinskii-Moriya interaction induces magnetic frustration in two dimensions, from which the competition with an external magnetic field results in a new mechanism producing skyrmions of nanoscale size. A single nanoskyrmion can already be stabilized in a few-atom cluster, and may then be used as LEGO^® block to build a large magnetic mosaic. The realization of such topological spin nanotextures in sp- and p -electron compounds or in ultracold atomic gases would open a new route toward robust and compact magnetic memories.

High-order harmonic analysis of anisotropic petahertz photocurrents in solids

Polarization maps of high-order harmonics are shown to enable a full vectorial characterization of petahertz electron currents generated in a crystalline solid by an ultrashort laser driver. As a powerful resource of this methodology, analysis of energy-momentum dispersion landscapes, defined by the electron band structure, can help identify, as our analysis shows, special directions within the Brillouin zone that can provide a preferable basis for polarization-sensitive high-harmonic mapping of anisotropic petahertz photocurrents in solids.

Effective Heisenberg Model and Exchange Interaction for Strongly Correlated Systems

We consider the extended Hubbard model and introduce a corresponding Heisenberg-like problem written in terms of spin operators. The derived formalism is reminiscent of Anderson's idea of the effective exchange interaction and takes into account nonlocal correlation effects. The results for the exchange interaction and spin susceptibility in the magnetic phase are expressed in terms of single-particle quantities. This fact not only can be used for realistic calculations of multiband systems but also allows us to reconsider a general description of many-body effects in the most interesting physical regimes, where the physical properties of the system are dominated by collective (bosonic) fluctuations. In the strongly spin-polarized limit, when the local magnetic moment is well defined, the exchange interaction reduces to a standard expression of the density functional theory that has been successfully used in practical calculations of magnetic properties of real materials.

Enhanced Error Decoding from Error-Related Potentials using Convolutional Neural Networks

Error-related potentials are considered an important neuro-correlate for monitoring human intentionality in decision-making, human-human, or human-machine interaction scenarios. Multiple methods have been proposed in order to improve the recognition of human intentions. Moreover, current brain-computer interfaces are limited in the identification of human errors by manual tuning of parameters (e.g., feature/channel selection), thus selecting fronto-central channels as discriminative features within-subject. In this paper, we propose the inclusion of error-related potential activity as a generalized two-dimensional feature set and a Convolutional Neural Network for classification of EEG-based human error detection. We evaluate this pipeline using the BNCI2020 - Monitoring Error-Related Potential dataset obtaining a maximum error detection accuracy of 79.8% in a within-session 10-fold cross-validation modality, and outperforming current state of the art.

[DIC-syndrome-related mortality in acute necrotic pancreatitis]

AIM

To improve the results of acute necrotic pancreatitis management via an analysis of changes in the main causes of mortality in patients with this disease over the last decade.

MATERIAL AND METHODS

We have analyzed medical records of patients with acute necrotic pancreatitis followed by lethal outcome for the period 2015-2016. In all cases autopsy was performed in order to determine morbidity and mortality. Complications of pancreatic necrosis significant for tanatogenesis, treatment and prevention strategy were compared with those for 2005-2006.

RESULTS

It was shown that not only significantly decreased mortality in acute necrotic pancreatitis but also important changes in its structure occurred for the last ten years. At present time DIC-syndrome and its organ complications are the most significant causes of death.

CONCLUSION

Prevention of DIC-syndrome and its complications is necessary to improve the outcomes. Endothelial protectors' administration in early period, timely diagnosis and adequate treatment of DIC-syndrome are advisable.

Excitonic Instability and Pseudogap Formation in Nodal Line Semimetal ZrSiS

Electron correlation effects are studied in ZrSiS using a combination of first-principles and model approaches. We show that basic electronic properties of ZrSiS can be described within a two-dimensional lattice model of two nested square lattices. A high degree of electron-hole symmetry characteristic for ZrSiS is one of the key features of this model. Having determined model parameters from first-principles calculations, we then explicitly take electron-electron interactions into account and show that, at moderately low temperatures, ZrSiS exhibits excitonic instability, leading to the formation of a pseudogap in the electronic spectrum. The results can be understood in terms of Coulomb-interaction-assisted pairing of electrons and holes reminiscent of that of an excitonic insulator. Our finding allows us to provide a physical interpretation of the unusual mass enhancement of charge carriers in ZrSiS recently observed experimentally.

Dynamical and Reversible Control of Topological Spin Textures

Recent observations of topological spin textures brought spintronics one step closer to new magnetic memories. Nevertheless, the existence of Skyrmions, as well as their stabilization, require very specific intrinsic magnetic properties which are usually fixed in magnets. Here we address the possibility to dynamically control their intrinsic magnetic interactions by varying the strength of a high-frequency laser field. It is shown that drastic changes can be induced in the antiferromagnetic exchange interactions and the latter can even be reversed to become ferromagnetic, provided the direct exchange is already non-negligible in equilibrium as predicted, for example, in Si doped with C, Sn, or Pb adatoms. In the presence of Dzyaloshinskii-Moriya interactions, this enables us to tune features of ferromagnetic Skyrmions such as their radius, making them easier to stabilize. Alternatively, such topological spin textures can occur in frustrated triangular lattices. Then, we demonstrate that a high-frequency laser field can induce dynamical frustration in antiferromagnets, where the degree of frustration can subsequently be tuned suitably to drive the material toward a Skyrmionic phase.

Solid-State Source of Subcycle Pulses in the Midinfrared

We demonstrate a robust, all-solid-state approach for the generation of microjoule subcycle pulses in the midinfrared through a cascade of carefully optimized parametric-amplification, difference-frequency-generation, spectral-broadening, and chirp-compensation stages. This method of subcycle waveform generation becomes possible due to an unusual, ionization-assisted solid-state pulse self-compression dynamics, where highly efficient spectral broadening is enabled by ultrabroadband four-wave parametric amplification phase matched near the zero-group-velocity wavelength of the material.

Mid-infrared-to-mid-ultraviolet supercontinuum enhanced by third-to-fifteenth odd harmonics

A high-energy supercontinuum spanning 4.7 octaves, from 250 to 6500 nm, is generated using a 0.3-TW, 3.9-μm output of a mid-infrared optical parametric chirped-pulse amplifier as a driver inducing a laser filament in the air. The high-frequency wing of the supercontinuum spectrum is enhanced by odd-order optical harmonics of the mid-infrared driver. Optical harmonics up to the 15th order are observed in supercontinuum spectra as overlapping, yet well-resolved peaks broadened, as verified by numerical modeling, due to spatially nonuniform ionization-induced blue shift.

Multioctave, 3-18 μm sub-two-cycle supercontinua from self-compressing, self-focusing soliton transients in a solid

Strongly coupled nonlinear spatiotemporal dynamics of ultrashort mid-infrared pulses undergoing self-focusing simultaneously with soliton self-compression in an anomalously dispersive, highly nonlinear solid semiconductor is shown to enable the generation of multioctave supercontinua with spectra spanning the entire mid-infrared range and compressible to subcycle pulse widths. With 7.9 μm, 150 fs, 2 μJ, 1 kHz pulses used as a driver, 1.2 cycle pulses of mid-infrared supercontinuum radiation with a spectrum spanning the range of wavelengths from 3 to 18 μm were generated in a 5 mm GaAs plate. Further compression of these pulses to subcycle pulse widths is possible through compensation of the residual phase shift.

Frequency-tunable sub-two-cycle 60-MW-peak-power free-space waveforms in the mid-infrared

A physical scenario whereby freely propagating mid-infrared pulses can be compressed to pulse widths close to the field cycle is identified. Generation of tunable few-cycle pulses in the wavelength range from 4.2 to 6.8 μm is demonstrated at a 1-kHz repetition rate through self-focusing-assisted spectral broadening in a normally dispersive, highly nonlinear semiconductor material, followed by pulse compression in the regime of anomalous dispersion, where the dispersion-induced phase shift is finely tuned by adjusting the overall thickness of anomalously dispersive components. Sub-two-cycle pulses with a peak power up to 60 MW are generated in the range of central wavelengths tunable from 5.9 to 6.3 μm.

A pseudopotential model for Dirac electrons in graphene with line defects

We consider electron transport in a planar fermion model containing various types of line defects modeled by δ-function pseudopotentials with different matrix coefficients. After determining the necessary boundary conditions, the transmission probability for electron transport through the defect line is obtained for various types of pseudopotentials. For the schematic model considered, which may describe a graphene structure with different types of linear defects, the valley polarization is obtained.

[Endoscopic retrograde cholangiopancreaticography for the treatment of necrotic pancreatitis]

40 patients with the acute necrotic pancreatitis and verified biliary hypertension were included in the study. During the endoscopic retrograde cholangiopancreaticography we avoided the main pancreatic duct contrast enhancement. The canulation during papillosphincterotomy (PST) was not used if the concrement was infringed in the ampulla. The use of these methods led to fast relief of the biliary hypertension and truthworthy positive dynamics of the disease course. The negative consequences were usually limited to transitory amilasemia and the pancreonecrosis progression was registered in only 4±4% cases. In comparison with cholecystostomy, the ERCP with PST showed better prognosis considering the frequency of septic complications and terms of hospital stay. The statistical analysis proved the the ERCP with PST are preferable to cholecystostomy in cases of pancreonecrosis with choledochlithiasis and biliary hypertension and the overall severity of pancreonecrosis is not higher than 11 by the physiological condition scale.

[Laparoscopic surgery in children--current possibilities and perspectives]

Experience in use of different laparoscopic methods in 6046 children who needed urgent and elective surgeries are analyzed. Urgent surgeries were performed in 3292 children for acute appendicitis and it complications, acute adhesive intestinal obstruction, invagination, trauma of abdominal organs, pathological changes of Meckel diverticulum, urgent inflammatory and non-inflammatory gynecological diseases. In this group endosurgery was successful in 3120 (94.8%) patients, conversion to open surgery was necessary in 5.2% cases (172 patients). Laparoscopic cholecystectomy, splenectomy, nephrectomy, surgeries for cysts of parenchymatous organs, benign cysts and tumors of abdominal cavity and retroperitoneal space, varicocele, syndrome of unpalpable testes and abdominal cryptorchism were performed as elective surgeries in 2754 patients. Endosurgical methods to minimized number of complications (1.1% or 29 patients in the whole group), conversion to open surgery was necessary in 10 (0.4%) cases. Laparoscopic methods in many cases are the "gold standard" in elective and urgent surgery in children.

[Artificial esophagus in children]

The aims of the study were: 1) to formulate up-to-date principles of coloesophagoplasty (CEP) and to compare methods of CEP; 2) to determine the optimal age for esophagoplasty in children with esophageal atresia; 3) to evaluate quality of life and long term results after esophagoplasty performed in childhood; 4) to present results of surgical treatment of pharynx stenosis in children. Over the last 50 years more than 2 thousand surgeries on the esophagus in children were performed including more than 600 operations of artificial esophagus creation. From 1995 in some patients we carried out extirpation of the esophagus with one-stage plastic operation coloesophagoplasty taken the transplant in the posterior mediastinum. From 1992 on the pharynx with free revascularized intestinal segment was performed in isolated stenosis of the pharynx. Case histories of 54 children aged from 3 months to 15 years were analyzed to compare methods of esophagoplasty when the esophagus was taken behind the sternum and in posterior mediastinum. Case histories of 27 children with atresia of the esophagus were analyzed for determination of optimal age for coloesophagoplasty. Responses to questionnaires were analyzed to evaluate quality of life. From 1980 ive hase operated 28 patients with scarry stenosis of the pharynx (isolated or in combination with esophageal stenosis). Current policy of surgical treatment of pharyngeal stenosis which is considered as surgery of choice-pharyngoplasty with a free intestinal transplant--is described. Development and clinical appliance of up-to-date principles of CEP permitted to reduce the number of complications and to decrease lethality from 3 to 0.5%. After introduction of antireflux cologastroanastomosis the number of complications due to reflux reduced. Extirpation of the esophagus may be valid in peptic stenosis, Barrett's metaplasia, tumors, portal hypertension or angiodisplasia, and in the majority of cases of scarry stenosis of the esophagus.

[Thoracoscopic and video-assisted surgeries on thoracic organs of children]

Forty-seven video-surgical thoracic operations performed in children are analyzed. Age of children ranged from 4 days to 14.5 years, body weight--from 700 g to 54 kg. Two types of surgeries are singled out--thoracoscopic and video-assisted (when minithoracotomy was performed in addition to thoracoscopic technique). There were no severe complications during surgery. One child died due to non-diagnosed penumothorax on the 4th day after surgery. Problems of anesthesia and surgical technique in children are considered.

[Preoperative care and surgical treatment of small-intestinal fistulas in children]

Experience in using complex treatment in 42 children with unformed small-intestinal fistulas, generalized defects of the anterior abdominal wall and severe disorders of alimentary status is presented. Their preoperative preparation included parenteral alimentation, enteral probe feeding with special elementary milk formulas, correction of metabolic disorders. Intestinoplication during surgery was carried out with the medicinal glue MK-7 to prevent intestinal obstruction and formation of interloop abscesses. The use of portions of the tendinous part of the musculus tensor fasciale late was one the simple and effective methods for plasty of anterior abdominal wall defects.

[Treatment policy for children with gastroesophageal reflux complicated by Barrett esophagus]

Barret's esophagus (BE) is a rare disease in children. It is caused by gastroesophageal reflux (GER). From 1996 to 1999 seventy-eighth children with GER were treated. Twenty-four-hour pH-metry and manometry of the esophagus, scintigraphy and contrast roentgenoscopy of the esophagus were used for diagnosis of GER. All the children underwent biopsy of mucosa membrane of distal esophagus. Morphologic examinations revealed BE in 16 (20.5%) children. Metaplasia of esophageal epithelium by intestinal type (IT) in combination with one by gastric type (GT) were revealed in 8 children, metaplasia by gastric type alone (epithelium of gastric and fundal parts of the stomach)--in 8 children. Six children with IT metaplasia of the esophagus with long strictures underwent extirpation of the esophagus with one-stage esophagoplasty. It esophageal stenosis is not long or is absent, fundoplication by Nissen (4 children) and drug therapy (6 children) are performed. It is concluded that in IT metaplasia of the esophagus with long peptic esophageal strictures resistant to bouginage extirpation of the esophagus with one-stage coloesophagoplasty is desirable. Other methods of treatment do not exclude probability of esophageal adenocarcinoma. These children should be followed up with esophageal biopsy each 6-12 months.

[Quality of life in patients after coloesophagoplasty, performed in childhood]

Based on questionnaire, the authors analyze long-term results of coloesophagoplasty in 32 patients operated from 1990 to 2000. At the moment of operation age of the children ranged from 3 months to 14 years (5 years, on the average). 1 (3.1%) patient died at the age of 15 years, 9 years after esophageal plasty. Long-term results were evaluated in 31 respondents. Most respondents (81.3%) evaluate their state late after coloesophagoplasty as good and satisfactory. All the respondents take meal without assistance 74% patients don't keep a diet. Respondents with severe concomitant diseases (VACNERL--syndrome, bullous epidermolisis, CNS disorders) evaluate their state as unsatisfactory. In children after coloesophagoplasty falling behind growth (48%) and weight (62%) was revealed due to disease and low living standard. 89.5% respondents evaluate their quality of life as satisfactory.

[Surgical treatment of fecal incontinence in children]

The experience of the faeces incontinence treatment in 295 children (age ranged from 1 to 15 years) is presented. Several original operations for surgical correction of the sphincter ani asthenia are proposed. The authors think that radical correction of faeces incontinence in children is necessary as early as at the age 6 to 7 years that is at the beginning of social activity. Efficient use of the above methods of the rectum closing apparatus creation allowed to achieve good results in 77.3-85.7% of the children.

[Development of methods of esophagoplasty in children]

In the Clinic of Pediatric Surgery of the Russian State Medical University 310 operations for esophagoplasty were performed using segments of the small and large intestine. The 50-year progress in the creation of an artificial esophagus is characterized by gradual advancement from prethoracic plasty after Roux-Herzen-Yudin to the refined method of retrosternal coloesophagoplasty. The incidence of the characteristic postoperative complications reduced by 3 to 10 times, necrosis of the transplant was practically not encountered, the mortality reduced to 1.2%, and the functional results improved significantly.

[Hirschsprung's disease in newborns]

The authors examined and treated 52 newborn babies and infants with Hirschsprung's disease. The total form was encountered in 25%, the subtotal in 23.1%, the rectosigmoid in 36.5%, the rectal in 9.6%, and the supraanal in 5.8% of cases. The clinical picture was characterized by retention of meconium (94.2%), regurgitation or vomiting (75%), abdominal distention (100%). Irrigography with calculation of the rectosigmoid ratio was conducted in 35 children, histochemical examination in 46, and histological examination in 38 children. Twenty-four (68.5%) children had the third phase of disturbed proportion of the intestinal bacteria with clinical manifestations of enterocolitis. Emergency decompression of the intestine for low acute intestinal obstruction was carried out in 27 newborn babies. Twenty children were subjected to radical surgery in the first 2-4 months of life. The choice of the operative method was guided by the form of the disease and the length of the aganglionic zone.

[Kidney autotransplantation in ureter injuries and diseases children]

Six operations for kidney autotransplantation into the ipsilateral iliac fossa were conducted on children aged from 2 to 14 years. In 2 children the operation was performed for a posttraumatic defect in the ureter of a considerable length. Severe neuromuscular dysplasia of the ureter in maintained function of the kidney was the indication for operating on 4 children. No complications occurred in 5 operations. One transplanted kidney had to be removed because of renal artery thrombosis resulting from damage inflicted to the endothelium during washing of the kidney. Operation for autotransplantation of the kidney is a permissible alternative of the traditional methods of replacement or plastics in long posttraumatic strictures and congenital developmental anomalies of the ureter.

[Portal hypertension in children: venous shunting in the early childhood]

Operations were carried out on 98 children with extrahepatic portal hypertension and on 6 with intrahepatic block and no signs of hepatocellular insufficiency. Mesenterico-caval H-shunt was formed in 78 children with the use of the internal jugular vein as the insert. The remaining children underwent formation of mesocaval anastomosis (8), distal spleno-renal shunt (4), portocaval anastomosis (1), Sugiura's operation (7). Among the operations 68 were planned, 12 emergency, and 18 preventive. The average age of the children was 6.5 years; 31 were under the age of 5 years and 19 under 3 years of age. The youngest child was aged 10 months, the H-shunt was successful. The results of the operation: thrombosis of the shunt 0%, portosystem encephalopathy 0%, recurrent hemorrhage 0%, lethality 1%. This is evidence of the expediency of performing shunting operations in early childhood.

[The treatment of intestinal fistulae in children by applying a by-pass anastomosis using magnetic devices]

A new method is suggested for the exclusion of intestinal fistulas by the formation of by-pass anastomoses by means of a permanent magnet. The variants of the techniques of magnet by-pass anastomoses are discussed. The results of treatment of 46 children with external intestinal fistulas are shown. With the formation of a by-pass compression anastomosis the mortality rate among children with intestinal fistulas reduced from 31 to 13%.

[The surgical treatment of congenital hydronephrosis in children]

Available are the results of surgical treatment (Andersen-Hynes operation and its modifications) of 85 children with hydronephrosis bor the period 1981-1987. The patients' age ranged from 6 months to 14 years. Anastomotic stenosis occurred in 12% of the procedures as a result of: urethral or pelvic trauma when suturing, wound channels due to the needle perforating puncture, catgut unwanted properties, tissue strain at the anastomosis site, inadequate renal drain. This necessitates modification of the operative technique: surgical manipulations restricted to the operated on pelvic part and pelvic-urethral segment, optical amplification, microsurgical instruments, synthetic suture. An original pyelostoma made of silicon rubber was used in draining. Out of 34 surgical cases, good results were achieved in 31, satisfactory in 3. No complications were recorded.

[A way to improve the quality of compression anastomoses of the urethra in children]

The paper presents the analysis of compression anastomosis establishment in surgical treatment of children with posttraumatic strictures of the posterior urethra. It is noticed that quality of the anastomoses deteriorates with enlargement of the interpolated tissues layer. Anastomosis is suggested to be formed between submucous layers. The new variant was tried in experiment on 9 dogs and in 5 patients with posttraumatic urethral strictures. As a result of more advanced anastomoses the thickness of the interpolated tissues reduced 2-3-fold. The techniques of the above surgery are discussed as well as the advantages of the proposed submucous compression anastomosis in posttraumatic strictures of the posterior urethra.

[Cysts of the common bile duct in children]

From 1975 to 1989 operations were carried out in the clinic by various methods on 30 children with cysts of the common bile duct. Hepaticoor choledochojejunostomy after Roux is the operation of choice in cysts of the choledochus. However, recurrent cholangitis caused by jejunobiliary reflux was encountered in some patients in the postoperative period. The accumulated clinical experience has also shown that the Roux type operation does not guarantee a successful functional result. To prevent reflux of the intestinal contents into the biliary tract after Roux's anastomosis, the authors used an antireflux valve on the excluded loop of the jejunum. Experimental study was undertaken of the theoretically substantiated antireflux valve on an excluded loop of the type of a "nonspilling inkpot" with a shortened loop. The creation of an antireflux valve in the form of an invaginated segment prevents jejunobiliary reflux and therefore provides the possibility for reducing significantly the length of the excluded loop in Roux's biliodigestive anastomoses. The obtained positive results confirm the rationality of this construction which does not need additional time for the operation. Since 1987 four children have been operated on by this method in the clinic. The length of the excluded loop was reduced from 30 to 15 cm. Postoperative complications linked with reflux into the biliary system were not encountered.

[Formation of a urinary reservoir from a small intestinal graft in children with exstrophy of the urinary bladder]

The authors suggest a new approach to the treatment of patients with exstrophy of the urinary bladder-the formation of an urinary reservoir from a detubulerized intestinal graft after II Kocks' method. This method, as well as its analogues, is mainly used in adults after radical cystectomy. Improved surgical techniques have been suggested on the basis of experimental works which allow the age features and the peculiarities of the functional condition of the formed reservoir to be taken into account. Analysis of the results of clinical use of the suggested method showed it to be effective in solving the problem of rehabilitation of patients with exstrophy of the urinary bladder, which allows it to be recommended as the operation of choice in the management of this developmental anomaly.

[Use of heterogenous materials in the surgical treatment of fecal incontinence in children]

Operations were carried out on 40 male and female patients with stage III incontinence of feces from 1970 and through 1980. Their ages ranged from 8 to 14 years. The disease was caused by unsuccessful correction of anorectal developmental anomalies. The following operations were performed: after Wreden on 16 patient, after Faerman on 12, after Makhov on 8 and after Thiersch on 4 patients. The follow-up periods ranged from 2 to 6 years. A recurrence was found in all of the children. Y-shaped sphincteroplasty and a modified Wreden's operation with the use of heterogeneous material have been developed and introduced into practice in the clinic since 1983. Twenty two patients with stage III incontinence of feces were operated on, the result was positive in the majority of cases.

[Diagnosis and treatment of adhesive intestinal obstruction in children]

The work analyses 455 patients with acute adhesive intestinal obstruction (194 children with the early and 261 with the advanced stage of the disease). The most common causes of the obstruction were acute appendicitis, developmental anomalies of the intestine, and intestinal intussusception. Complete viscerolysis and horizontal intestinoplication by means of medical glue without application of sutures were performed in a total adhesion process, even in the acute period (34 cases). Severe paresis or paralysis of the gastrointestinal tract is an indication for its decompression. Laparoscopy was conducted in 90 children (from 3 months to 14 years of age) in suspected acute adhesive intestinal obstruction. The diagnosis was confirmed or defined more exactly in 64 patients. As the result of endoscopic operations intestinal obstruction was corrected and laparotomy was avoided in almost half of the patients. The total mortality was 1.3%.

[Diagnostic and therapeutic tactics in various forms of cholangiopathies in children]

Seventy children with obstructive cholangopathy were examined in the clinic in the recent 15 years: 48 children had "cholangiopathy of the newborn" and 22 had a cyst of the common bile duct. A total of 44 operations were carried out: on 22 infants with cholangiopathy of the newborn and on 22 with cysts of the common bile duct. The most informative methods for the diagnosis of cholangiopathy in children are as follows: ultrasonic scanning, laparoscopy, ERCPG, aspiration biopsy of the liver, and aspiration cholangiography under control of a laparoscope. Kasai's operation is the operation of choice in obstructive cholangiopathy of the newborn. The operation of choice in cysts of the common bile duct is cystectomy with choledocho- or hepaticojejunostomy on an isolated loop after Roux.

[Treatment of short urethral strictures in children using magnets]

In 20-35 per cent of short (up to 05 cm) urethral stenosis or cicatricial obliterations of urethra it was found advisable to start the treatment with nonoperative technique. Before 1982 bouginage or tunneling of urethra were commonly used. In 5 out of 6 children the strictures relapsed. Since 1983 when permanent magnets were employed, in 4 out of 5 patients normal urination recovered. 1 child was exposed to preventive 5-months bouginage to ensure constant patency of urethra. Long-term results in all the children satisfied the investigators. But out of 3 magnet-treated children with longer strictures (more than 1 cm) the disease relapsed in 2. It was concluded that in patients with longer stenosis the method was a failure, but in those with short ones the technique was more effective than routine methods. Besides, technical availability, safety and shorter terms of the treatment could also be regarded as the benefits of the aforementioned therapy.

[Surgical treatment of urethral strictures in children]

Under analysis were results of treatment of posttraumatic strictures of the urethra in 34 children. A method of treatment of the urethra structures has been developed in experiments in dogs with the use of permanent magnet. Comparison of results of treatment of 2 groups of patients treated by traditional methods (19 patients) and by the proposed method (15 patients) has shown that using the new method is followed by two times less amount of recurrences and complications.