In the article are presented classifications, causes and epidemiology of acute kidney injury (AKI) in newborns, unsolved problems. Neonatal AKI classifications proposed by Acute Kidney Injury Network (2007), JG Jetton, DJ Askenazi (2012), modifications from NKC, KDIGO, and AWAKEN (2016), AKI Workshop (2017) are discussed. The results of the international assessment Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN), JG Jetton et al (2016, 2017) are discussed. Of the 2022 babies, 605 (30 %) had the status of AKI: in 48 % of the 273 preterm neonates with gestatoinal age 22-29 weeks; 18 % of 916 preterm neonates with gestatoinal age 29-36 weeks; in 37 % of 833 neonates with gestatoinal age after 36 weeks. The risk factors for the development of early AKI in preterm infants include low gestational age and very low birth weight. According to international epidemiological studies, the development of AKI in premature newborns is the main and independent risk factor for mortality and the formation of chronic kidney disease. The absence of multicenter epidemiological studies of acute kidney damage in newborns in our country is still an unsolved problem. The solution of the problem facing the national neonatology should be aimed at ensuring a unified approach to the classifications of acute kidney damage, on studying epidemiology, features of development, course, and outcome of acute kidney damage of various etiologies, on developing algorithms for prevention, diagnosis and treatment in term and preterm infants.

In the literature review are presented the etiology, clinical and genetic features of congenital and infantile nephrotic syndrome (NS) in children, as of isolated and with extra-renal manifestations. Congenital NS is diagnosed in children from birth to 3 months, infantile NS – from 4 to 12 months. Clinical and genetic features of hereditary variants of congenital and infantile NS in children caused by mutations of genes encoding the main components of slit diaphragm, glomerular basement membrane and the cytoskeleton of the podocyte feet are described. R. Preston et al (2019) believe that clinical phenotyping combined with targeted genetic analysis is effective in diagnosing steroid-resistant congenital and infantile NS in children. Currently, genetic testing is recommended before initiating immunosuppressive therapy and performing a biopsy of the kidney. Mutational screening of genes is shown in hereditary variants of congenital (NPHS1, NPHS2, WT1, LAMB2, PLCE1, LMX1B) and infantile (NPHS2, NPHS1, WT1, PLCE1, TRPC6, ACTN4, ADCK4, COQ2, COQ6) NS in children. The NPHS1 mutation detection rate remains high amongst non–Finnis cases of congenital NS. In international practice, with the aim of early diagnosis and treatment of steroid-resistant congenital and infantile NS in children, modern methods of mutational screening are used. Renal biopsy fades into the background. The literature review presents a modern strategy of drug and early renal replacement therapy. Recommendations for the management of Finnish-type congenital NS in children followed by many teams include daily albumin infusions, early bilateral nephrectomy, dialysis, and transplantation. The 5-years survival of patients with congenital and infantile nephrotic syndrome after kidney transplantation is more than 90 %, the survival rate of the renal allograft is more than 80 %.

The goal is to discuss the criteria for the early diagnosis of chronic kidney disease (CKD) in children. The article presents data from modern literature on the epidemiology, classification, and criteria for the diagnosis of CKD, own scientific results on clinical and paraclinical characteristics of CKD and regional characteristics of CKD in children of the Orenburg region. Modern approaches to the early diagnosis of CKD in children, the identification of risk factors for the progression of nephropathy and the algorithm for the diagnosis of CKD in childhood, taking into account unfavorable regional factors, are scientifically substantiated. A set of measures for the prevention of nephropathy and a scheme of follow-up observation of children at high risk has been developed. The ways to improve the children's nephrology service are substantiated. Modern pathogenetic approaches to the diagnosis of CKD in children are presented. An algorithm for diagnosing the initial stages of CKD in children at risk for CKD and children with renal pathology without CKD with a preliminary selection of anamnestic and clinical and paraclinical indicators is proposed.

The review contains materials on the course of chronic kidney disease (CKD) in children with arterial hypertension (AH). The relationship between CKD and AH was shown, where hastening of CKD progression to end-stage renal failure in the presence of AH was established. The regulation of AH in children is necessary for the treatment of CKD, because AH is not established on time, is not well controlled and is often masked. Impaired vascular regulation, fluid overload, increased cardiac output, and peripheral vascular resistance, alone or in combination, can lead to hypertension in CKD. The use of modern methods for monitoring and controlling blood pressure is crucial to improve the management of AH and prevent damage to target organs in children. 24-hour blood pressure measurements are an important tool in determining the prognosis and treatment of children with CKD. To identify impaired renal function in CKD, a large number of biomarkers are used. Glomerular filtration rate (GFR), serum creatinine and cystatin C are currently used as biomarkers for renal failure. Recently, biomarkers, including KIM-1, LFABP, NGAL, and IL-18 have been proposed as markers of acute kidney injury, and they may be useful in the future for early detection of CKD progression in children. In newborns and children of early and older age, hypertension occurs due to renovascular and parenchymal diseases.

AH is considered a marker of CKD severity and is a risk factor for progressive deterioration of kidney function, as well as thedevelopment of cardiovascular diseases. Sympathetic hyperactivity, excessive formation of free radicals, reduced bioavailability of nitric oxide (NO) and excessive production of angiotensin II leads to an increase in blood pressure. Obesity or an increase in body mass index (BMI) is currently considered as a risk factor not only for cardiovascular diseases and diabetes but also for CKD. Hyperuricemia and CKD are closely related, as the accumulation of uric acid is associated with hypertension, metabolic syndrome and microalbuminuria, which are also risk factors for the progression of CKD. AH has a detrimental effect on target organs, including the kidneys, eyes, and heart. Lifestyle modifications, weight control, healthy eating, reduced sodium intake, maintenance exercises and basic drug therapy using angiotensin-converting enzyme inhibitors (ACE inhibitors), angiotensin receptor blockers can slow the progression of CKD in children.

The article presents current information on the pathogenetic role of lipid metabolism disorders and the value of lipotoxicity in renal pathology, contributing to the progression of nephropathy. The detected increase in cholesterol level, TAG, LDL, decrease in plasma HDL concentration in chronic kidney disease (CKD) is accompanied by significant changes in the composition of various lipoproteins caused by changes in the expression and activity of key proteins and enzymes involved in the biosynthesis, transport, remodeling and catabolism of lipids and lipoproteins. It has been proven that dyslipidemia in CKD affects the morphological and functional state of the kidneys, contributing to the development of renal lipotoxicity processes, affecting the structural and functional state of the kidneys, initiating oxidative stress, systemic inflammation, vascular damage, and dysregulation. To date, research on the significance of dyslipidemia as a pathogenetic factor in the formation of chronic kidney disease remains insufficiently studied. Dysregulation of lipid metabolism, leading to dyslipidemia, is often an undervalued complication of CKD.

Analyzed the current status of chronic glomerulonephritis (CGN) in children, listed the known aspects of pathogenesis and what remains to be studied. In particular, data on the burden of disease (incidence, prevalence, rate of progression) are missing or limited; available information on the relationship of known risk factors regarding morbidity, prevalence and progression are limited; insufficient data on the importance of maternal health factors and fetal risk factors. Genetic causes of CGN vary in different places and knowledge remains limited. CGN is characterized by genetically determined immuno-mediated inflammation of the renal glomeruli, accompanied by the integration of all the structures of the kidneys into the pathological process. The data on the association of NPHS1 and NPHS2 polymorphisms that play an important role in the molecular mechanisms of nephrotic syndrome in various populations are presented. It is noted that in the European population the most frequent polymorphism associated with steroid-resistant nephrotic syndrome (NS) is R138Q (rs74315342). NPHS1 and NPHS2 are common among Iranian children with steroid-resistant NS, and p.R229Q mutations are not registered. In contrast to Iranian adolescents, in the Russian population in children with this pathology, a frequent association of the polymorphic marker R229Q in the heterozygous state was revealed. A low mutation rate in NPHS1 and NPHS2 was found in Pakistani children with NS, whereas in children with NA, from the Iranian population, NPHS1 rs437168, but not NPHS2 rs61747728, was associated with NA. Several studies have shown that mutations in the NPHS2 gene occur in 20 % to 30 % of sporadic cases of steroid-resistant NS. Attention is drawn to the lack of knowledge of the polymorphism of these genes in Azerbaijani children with CGN.

BACKGROUND. Studies on the problem of IgM nephropathy in children in the world literature are few. Data on the disease in adults and children In Belarus have not previously been presented.

THE AIM: to analyze the clinical, immunological, morphological characteristics, treatment regimen and prognostic factors of IgM nephropathy in children.

PATIENTS AND METHODS. The study included 153 patients during the 6 years observed in the Republican Center for Pediatric Nephrology, among whom 21 were diagnosed with IgM nephropathy.

RESULTS. Analysis of clinical, morphological features, the participation of markers of activation of T- and B-lymphocytes, pro-inflammatory and profibrotic molecules was performed.

CONCLUSIONS. In most cases, IgM nephropathy is characterized by steroid dependence or resistance, or frequent relapses, which dictates the need to join cytostatic agent. In childhood is characterized by a benign course with no signs of progression.

THE AIM: to characterize the features of the course of autosomal dominant (ADPKD) and autosomal recessive (ARPKD) polycystic kidney disease detected in the prenatal, neonatal and thoracic periods.

PATIENTS AND METHODS: ADP was diagnosed in 28 and ARPP in 12 of 40 children and adolescents. The dynamics of the diameter of renal cysts (mm), total kidney volume (TKV, cm3) by ultrasound were evaluated; Constructed trend lines for average TKV and diameter of renal cysts. The glomerular filtration rate is determined by the Schwartz formula. Liver fibrosis was detected by ultrasound / MRI / CT / biopsy.

RESULTS: ADPKD was detected prenatally and during the first year of life in 19.1 %, ARPKD in 70.6 %. Stable arterial hypertension was diagnosed with an ADPKD with “very early detection” in 7 % (among adolescents), with ARPKD in 100 % (under 3 years of age). The diameter of the renal cysts increases with ADPKD. Renal cysts are multiple, bilateral since birth with ARPKD, the diameter of the cysts does not increase. TKV increased at birth in 3.6 % of children with ADPKD, in 100 % with ARPKD. The trend line of average TKV with ADPKD is exponential, with ARPKD – linear. Extrarenal location of cysts was diagnosed with ADPKD in 3.6 % (in the testes), with ARPKD in 67 % (in the liver). Liver fibrosis with portal hypertension syndrome was detected in children with ARPKD in 33.3 %; performed ligation of the veins of the esophagus. Acute kidney damage was found in newborns with ADPKD in 3.6 %, with ARPKD in 33.3 %. Fatal outcome was ascertained in 3 (25 %) children with ARPKD. In the follow-up, the outcome in HBPS3 is in 2 children with ADPKD and 3 children with ARPP, in HBPS4 in 1 child with ARPKD.

CONCLUSION: features of the course of ADPKD and ARPKD revealed in the prenatal, neonatal and thoracic periods are shown.

THE AIM: to compare the parameters of physical development (PD) in children with idiopathic nephrotic syndrome (INS), depending on the treatment with prednisone.

PATIENTS AND METHODS. The effect of treatment with prednisone on PD was analyzed in 60 children with INS aged from 2 to 17 years. The children were divided into 2 groups: 30 children who did not receive prednisone, and 30 children who received it during the last 6 months before the study (1st and 2nd group, respectively). The groups compared the anamnestic parameters and the risk factors of children in terms of length, weight, and body mass index.

RESULTS. When comparing the characteristics of the risk factors of children of the above 2 groups, differences in body mass and BMI were established. In children who received prednisone for the last 6 months, body weight and BMI were significantly exceeded compared to WHO standards and similar patients who did not receive prednisone for the last 6 months. We have established a reliable association of the Z-BMI criterion with the cumulative dose of prednisone in the last 6 months: r = 0.49, p <0.05. At the same time, no reliable association of body weight with a cumulative dose of prednisone, which the child received before 6 months, has been identified. When analyzing the effectiveness of different doses of prednisone therapy for stopping relapses in children with steroid-sensitive INS, it was found that the onset and duration of remission did not significantly differ when taking standard (60mg/m²/day or 2 mg/kg/day) and half as much (1mg/kg/day) doses of prednisone.

CONCLUSION. The relationship of the body mass of children with INS and the cumulative dose of prednisone in the last 6 months has been established. When treating a recurrent steroid-sensitive non-relapsing INS, a decrease in the daily dose of prednisone from 2 mg/kg/day to 1 mg/kg/day is possible in adolescents who are afraid of steroid obesity or who have had severe complications during previous courses of prednisone therapy.

THE AIM: to study changes in the NO-mediated dilatation mechanism in the pial arteries of the brain of nephrectomized rats.

MATERIALS AND METHODS: The study was conducted on Wistar-Kyoto rats. At 4 months of age, a two-stage nephrectomy was performed. After 3 months, the reaction of the arteries of the pial membrane of the brain to agonists and antagonists was investigated by in vivo microscopy (the diameter of the arteries was measured against the action of acetylcholine, sodium nitroprusside and methylene blue). Besides, the perfusion of the brain tissue was measured for subsequent calculations of the values of the components of the vascular tone.

RESULTS: It was shown that the application of acetylcholine to the pial membrane led to a change in the diameter of the arteries. In nephrectomized rats under the action of acetylcholine, a significantly larger number of arteries in the constriction state was registered compared to the control group. The effect of sodium nitroprusside in the control group was accompanied by a dilatation of 100 % of the pial arteries; in the nephrectomized rat group, dilatation was detected in 83.2 ± 4.7 % of the arteries. When methylene blue was used in a group of nephrectomized rats, a smaller number of arteries in the constriction state was detected as compared to the control group.

CONCLUSION: In nephrectomized rats, pronounced disorders of the NO-mediated mechanism of the pial arteries of the brain were found, leading to an increase in the endothelial component of the vascular tone. The endothelium of the pial arteries of nephrectomized rats produces less NO both spontaneously and when stimulated with acetylcholine. In nephrectomized rats, abnormalities in the signal cascade of NO →sGC → cGMP in the smooth muscle cells of the pial arteries were revealed, which is confirmed by their lesser ability to dilate to the use of exogenous NO.

THE AIM: to show a rare combination and possible pathogenetic relationship of thrombotic microangiopathy and acute lymphoblastic leukemia in a child.

PATIENTS AND METHODS. The analysis of the history and clinical laboratory data of the patient.

RESULTS. 9 months after the debut of thrombotic microangiopathy with damage to the central nervous system, acute lymphoblastic leukemia was diagnosed in the form of transient attacks of cerebral circulation and kidneys with the development of the nephrotic syndrome. The literature data show that in rare cases secondary thrombotic microangiopathy precedes the unfolded picture of hematologic disease, pathogenetic therapy of leukemia leads to remission of thrombotic microangiopathy. The article discusses the possible relationship between the two states in a child.

CONCLUSION. Although the relationship of thrombotic microangiopathy and acute leukemia in the present case is not obvious, the authors believe that it is necessary to remember about the possibility of developing secondary microangiopathy on the background of oncohematological diseases, and in doubtful cases to conduct a study of the bone marrow in patients.

The article presents the terminology and classification in accordance with the International Сhapel Hill Сonsensus Сonference nomenclature of vasculitides (2012), clinical, immunological and morphological manifestations, therapy strategy and outcome of Antineutrophil cytoplasmic antibody vasculitides (ANCA) renal associated vasculitis (microscopic polyanghiitis, granulomatosis with Wegener's polyangiitis, eosinophilic granulomatosis with polyangiitis Churg-Strauss) in children and adolescents. IgG class antibodies to MPO and PR3, histopathological changes in renal biopsy specimens are considered the gold standard in the diagnosis of ANCA-glomerulonephritis. Following the recommendations of The European Vasculitis Study Group (EUVAS) in adult patients, ANCA-associated vasculitis describes the categories of disease severity: localized, early systemic, severe, generalized, refractory. An algorithm for the treatment of ANCA-associated vasculitis, recommended by EULAR (2009) for adult patients and adapted for children of L.A. Plumb et al (2018), which provides for a differentiated approach to the induction of remission in localized, early systemic, severe, generalized, refractory categories of severity and supportive therapy in localized, early systemic, generalized categories, second-line therapy. In most cases of ANCA-associated renal vasculitis in children and adolescents, it is kidney damage that manifests rapidly progressive glomerulonephritis with acute kidney damage, determines the severity and prognosis of outcome in terminal uremia. It seems important and necessary in the treatment protocols of ANCA-associated vasculitis to include a strategy for pre-dialysis and dialysis of rapidly progressive glomerulonephritis with acute kidney damage in children and adolescents.

This article is the continuation of analysis and discussion from the book by Professor AI Nevorotin "Matrix phraseological collection: a manual for writing a scientific article in English". The Matrix phraseological collection is a kind of catalog of text samples. The samples were from articles selected from the leading English-language scientific journals and were systematized in such away that when writing an article in English, a Russian researchers are able easy to find examples suitable for his/her own work. Furthermore, the selected samples can be transformed accordingly saving the semantic and syntactic relations between the elements and, finally, be inserted into the text. The second part of this work is devoted to the detailed analysis of the English scientific literature and also the section "Legality of the provisions of the problem".