In 2002 a group of Acute Dialysis Quality Initiative (ADQI) experts developed definition of acute renal failure (ARF) and created the system of stratification of its severity (RIFLE-criteria). In 2004 the concept of «acute kidney injury» (AKI) was offered, and in 2007 study group of Acute Kidney Injury Network (AKIN) presented a system of criteria for diagnostics and assessment of the injury severity (AKIN-criteria), this system is a modified RIFLE classification. Both systems have proved in practice their use to predict the AKI development and its outcome for the critical-ill patients. However, initially either RIFLE scheme, or AKIN scheme were not intended to include patients with acute primary parenchymatous kidney diseases what cannot meet the demands of nephrological society. We have offered modification of AKIN system which could help to eliminate this restriction. Nevertheless, results of some latest works, including ours, give the reason to suggest, that available RIFLE or AKIN criteria should be essentially revised. When diagnosing and estimating the AKI severity special attention should be paid to the initial state of kidneys function and, what is most important, to absolute but not relative changes in concentration of serum creatinine.

The elaboration of a method and evaluation of the influence of changes in the function of nephron on the final phase of urine formation in collecting ducts is of great theoretical and practical importance. In experiments performed in female Wistar rats the features of urine formation in water diuresis were studied (peroral water load of 5 ml/100 g body weight), in saluresis (furosemide 1.0 mg/100 g body weight i/m, 1-deamino-arginine vasotocin (1d-AVT) 0.05 μg/100 g body weight i/m), and in osmotic diuresis (i/v 0.75 ml/100 g body weight of 40% polyethylene glycol-400 (PEG) solution). Urine and blood serum osmolality was determined by cryoscopic method, Na⁺ and K⁺ concentration – by flame photometry, Mg²⁺ and Ca²⁺ concentration – by atomic absorption spectrometry. In all cases, except ones with water diuresis, polyuria was caused by increased excretion of osmotic-active substances and was accompanied by a rise of reabsorption of free water after PEG and 1d-AVT administration. Calculation of the ratio of the solute-free water clearance (T^c_H2O) and osmotic clearance (C_Osm) has revealed the similarity of values following 1d-AVT and PEG administration (0.55±0.09 and 0.49±0.09, respectively), in contrast to furosemide injection (-0.03±0.04) that decreased free water reabsorption. The data obtained show that in saluresis and osmotic diuresis the volume of the reabsorbed free water depends on the rate of the fluid flow into the collecting duct against a background of high osmotic permeability of its wall. On the contrary, furosemide reduces osmotic permeability and free water reabsorption. Thus, characteristics of renal function in various forms of diuresis and the use of new approach in calculation of T^c_H2O/C_Osm allow to provide complete conception of the processes in renal medulla depending on the state of the system of urine osmotic concentration.

The article presents the data on pathogenesis of endothelial dysfunction in metabolic syndrome. Clinical and pathogenetic features of endothelial dysfunction are described. The problem of methods for diagnostics of endothelial dysfunction is covered. The role of microalbuminuria is shown. Probable approaches to the treatment of endothelial dysfunction are submitted.

Diagnostics of chronic kidney disease (CKD) can be based on the revealing of any morphological and clinical markers of kidney injury depending on a clinical situation. Proneinuria, changes in the urinary sediment, results of blood and urine analyses, changes observed with the use of functional and visualizing methods of examination could be considered as routine laboratory markers of kidney injury. In clinical practice in the absence of any other signs of chronic kidney injury the severity of albuminuria is the only and comparatively early indicator, allowing to exclude or to confirm the presence of subclinical CKD course, especially in conditions of remaining glomerular filtration rate. The rise of remote renal and cardiovascular risks also associates with microalbuminuria (30-299 mg/days). Nevertheless, the available data allow to consider it expedient to decrease the upper level of normal urinary albumin to 15 mg/day, instead of 30 mg/days as it is now in usual clinical practice. The necessity of use of CKD stages indexation in clinical practice depending on the level of albuminuria/proteinuria is discussed; it allows getting important information ina compact form to estimate the longterm prognosis for the kidney dysfunction and to plan preventive measures.

Vascular calcification in patients with chronic kidney disease (CKD) progresses much faster and essentially worsens their survival rate. Calcification is an active process similar to bone formation, caused by transformation of smooth muscle cells in osteoblast-like ones under the influence of the adverse factors connected with CKD. The extent of calcification can be evaluated quantitatively by means of simple and informative X-ray examination of abdominal aorta. According to our data the severity of abdominal aorta calcification (AAC) in patients with CKD of 1-5 stages increases along with a decrease of glomerular filtration rate and is connected with progressive atherosclerosis and its risk factors, which in their turn, are associated with phosphorus-calcium imbalance. These factors dominate in calcification genesis in patients with CKD of 5d stage being on a hemodialysis. For the first time it is revealed, that more expressed AAC is interrelated with a decrease of mineral bone density. The long-term treatment by active forms of vitamin D is associated with the lessening of AAC extent in the patients receiving a hemodialysis.

Definition of a concept of «oxidative stress» is presented in the article, the most important oxidants and mechanisms of their injuring action are listed. Patterns of disorders connected with oxidative stress are discussed. Special attention is given to lipids as the main targets of oxidative processes in the organism, the markers of oxidative stress are named. General characteristic of the system of antioxidant protection of the organism, as well as characteristic of oxidants of different origin and mechanism of action is given. The importance of oxidative stress in pathogenesis of chronic kidney disease is discussed. The own findings of the authors are presented.

The risk of development of cardiovascular pathology increases in early stages of chronic kidney disease (CKD) and probably is connected with phosphorus-calcium metabolic disorder - an early diminution in concentration of the active form of vitamin D – 1.25 (OH)₂D (calcitriol) and a rise of parathormone serum level. Pathogenesis of secondary heperparathyroidism, a decrease of calcitriol serum concentration is discussed in the review. The own data confirm an early disorder of hormonal regulation of phosphorus-calcium metabolism (from the 2^nd stage of CKD). It is found for the first time, that the curve of phosphate serum level has the U-shaped form, i.e. phosphate values decrease in the 2^nd stage of CKD and then quickly rise from the 4^th stage. As CKD progresses there is a decrease of calcium and phosphate excretion with urine, possibly caused by a decreased calcitriol blood level.

Despite an active development of experimental pharmacology, studying the influences of medicinal preparations on the renal functions is still rather uneasy problem. It is connected with unique physiology of a kidney, as well as with complexity and uncoordination of methodical technologies. Therefore we have tried to originate the unified methodical aids that, in our opinion, could be of use in the research work. The given article presents methods of screening investigations of drug renal effects, as well as methodical approaches to deeper studying kidneys functions - activity of glomerular filtrations, tubular secretion and tubular reabsorption; water diuresis; study of the renal elimination of medicinal agents; experimental modelling of renal diseases (oxalic nephrolithiasis, Masugi’s nephritis).

Development of biopsy methods and modern means of visualization (spiral computer and magnetic-resonance tomography, ultrasonic examination) allow to define more precisely the character of tumor growth and its localization, in this connection the possibilities of local intervention in the prostate neoplasm foci are of growing interest. At present the intervention is carried out on the whole prostate, including radical prostatectomy, though in 10-50% of patients it is more expedient to influence only a half of the prostate or to perform local therapy of particular tumor foci. The main arguments against local treatment: possibly not revealed multi-focal neoplasm, insufficient accuracy in staging procedure, unpredictable aggressivity of the secondary foci and the absence of common technological standards for these methods. Potential developing technologies of local treatment include focused ultrasonic radiation of high intensity, cryotherapy, radio-frequency ablation and photodynamic therapy. Further study of indications, efficiency and follow-up results of available methods will permit to introduce them into clinical practice, and itwill become possible in some cases to refuse radical prostatectomy when treating patients with localized forms of the prostate gland cancer.

Retroperitoneal fibrosis – is a nonspecific non-purulent inflammation of a fibroadipose tissue that causes symptoms owing to a gradual compression of tubular structures of retroperitoneal spaces. There are primary (idiopathic) and secondary retroperitoneal fibroses (RPF) are distinguished. In the development of idiopathic RPF the leading part belongs to autoimmune mechanisms. The secondary RPF is a consequence of various causes with medication among them. Intravenous urography is traditionally used to confirm the diagnosis of retroperitoneal fibrosis. The triad showing the presence of retroperitoneal fibrosis includes: 1) hydronephrosis with dilated gyrose upper segment of the ureter, 2) medial deviation of the ureter and 3) external compression of the ureter. Idiopathic retroperitoneal fibrosis is often curable when treated with corticosteroids and/or with additional immunosuppressive agents. At the same time for patients, especially for those with diffuse disease, surgical intervention is often required in order to release ureters and other structures with the aim to reduce obstruction.