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Currently, the attention of the medical community to a non-invasive method of laboratory diagnostics - the study of oral fluid (oral, saliva, saliva test) in various fields of clinical medicine and mainly in adult patients has been updated. Saliva testing has shown good results, especially in the areas of genomics, microbiomics, proteomics, metabolomics, and transcriptomics. The review presents the possibilities of using a non-invasive method for infectious and non-infectious diseases in children. Saliva contains a wide range of protein DNA and RNA biomarkers that help detect many viral infections in children. Oral fluid tests for human immunodeficiency virus, hepatitis B virus have improved access to diagnostics for infants. Both serological and molecular analyzes of the oral fluid are suitable for routine examination and early detection of measles virus RNA, polyomaviruses. Angiotensin-converting enzyme-2 receptor expression was found in the saliva of children with COVID-19, which can be used to diagnose SARS-CoV-2. The saliva test is as effective as the standard test at identifying asymptomatic individuals in contact tracing. The possibilities of saliva diagnostics are positively assessed in transplantology. New biomarkers in saliva have been identified for the diagnosis of many somatic diseases in children. The role of oral fluid as an alternative to blood serum in patients with terminal renal failure, chronic kidney disease (determination of creatinine, urea) in both adults and children is shown. The data obtained may influence the recommendations for the treatment of patients. As a non-invasive method, the study of oral fluid is promising for the diagnosis, prognosis, monitoring of diseases, large-scale typing of children, and the search for new biomarkers.

Purpose of the Study: assessment of the course and outcomes of the lupus nephritis in children; determination of the efficiency of use of the angiotensin-converting enzyme inhibitors for the lupus nephritis. Children Characteristics and Study Methods. Over a 20-year period, we analyzed the data of 36 children with the systemic lupus erythematosus and lupus nephritis at the ages from 5 to 17 years. Results. In 72.2% of the cases, the kidney damage was noted at the disease onset, and the severe, recurrent course of the lupus nephritis was registered. The nephrotic syndrome has developed in 47.2% of cases. All patients received the comprehensive treatment: corticosteroids, cyclophosphamide, azathioprine, selective immunosuppressants. A study was conducted for 23 children to determine the efficiency of the enalapril treatment prescribed for the purpose of the nephroprotection. It was revealed that this drug improves the long-term results. There was registered the twofold decrease in the disease recurrence rate, fivefold decrease in the level of daily proteinuria. Five-year survival rate was observed in 100% of the patients, 10-year – in 91.6%, end-stage renal failure was diagnosed in 8.4% of the children. 5 patients died in adult life (mortality rate is 13.9%). Conclusion. The children with the lupus nephritis require the continuation maintenance therapy. The use of the selective immunosuppressants and nephroprotectors has contributed to the renal survival.

Different modifications of acousto-optic modulators (AOMs) based on KG(WO4)2 (KGW) and KY(WO4)2 (KYW) crystals, designed for Q switching of high-power pulsed lasers, is developed and investigated. It is shown that AOMs based on these crystals are universal, can be combined with different lasers in the wavelength range of 1 – 3 μm, and have a high radiation resistance in the absence of antireflection coatings and light input at Brewster’s angle. The operation efficiency of KGW-based AOMs is experimentally demonstrated. Solid-state lasers based on Cr : Er : YSGG (λ = 2.78 μm), Cr : Yb : Ho : YSGG (λ = 2.87 μm), Cr : Tm : Ho : YSGG (λ = 2.09 μm), and Nd : YAG (λ = 1.064 μm) crystals with active acousto-optic Q switching, operating in the repetitively pulsed regime with a high beam quality and without surface destruction, are investigated. Lasing pulses (30 – 60)-ns long with energy up to 32 mJ at a repetition rate from 1 to 1000 Hz are obtained.

Diagnostics of Iron deficiency anemia (IDA) in outpatient pediatric practice is often based on decreased hemoglobin level. Latent iron deficiency diagnostic is not a part of current routine practice.Objective. To study the diagnostic value of red blood cell indices and reticulocyte hemoglobin equivalent in diagnostics of iron deficiency in full-term infants.Children characteristics and research methods. A prospective cohort study of healthy full-term children aged from 6 to 12 months at the children hospitals of Samara and Tolyatti. The laboratory examination included a general blood test to determine the concentration of hemoglobin, the number of red blood cells, red blood cell indices, and reticulocyte hemoglobin equivalent (Ret-He); to determine serum ferritin and C-reactive protein. The AUC (area under the curve) was used to determine the diagnostic value of quantitative indicators. The children with anemia without iron deficiency and children who received iron supplements within 1 month prior to laboratory examination were excluded from the analysis.Results. The study involved 207 children. When diagnosing iron deficiency in children, the highest AUC was found in Ret-He: 0.747 [0.679; 0.816] in 6-months-old children and 0.790 [0.708; 0.871] in 1-year-old children. The Ret-He diagnostic value was higher in children with iron deficiency: AUC 0.826 [0.754; 0.898] in 6- months-old children and 0.865 [0.809; 0.920] in 1-year-old children.Conclusion. Ret-He is a better predictor of iron deficiency in children under 1 year as compared to the red blood cell indices. The diagnostic value of red blood cell indices and Ret-He is higher in case of iron deficiency anemia than in case of iron deficiency conditions.

Purpose. To identify the effects of gestational iron deficiency anemia after treatment with iron-containing drugs during the perinatal period on the health status of full-term children during their 1st year of life.Patients and methods.The authors carried out a prospective observational cohort study of full-term infants of I & II health group from their birth to twelve months. The course of pregnancy and labor was analyzed retrospectively. Hemoglobin, serum ferritin and C-reactive protein were measured in the six and twelve months old children and their mothers in 6 months after giving birth. We examined 140 couples of mother-child with gestational anemia (Group 1) and 166 couples without anemia during pregnancy (Group 2) in 6 months after giving birth, and in 12 months – 103 and 131 couples respectively. All women with iron deficiency anemia (Group 1) received therapy during pregnancy. Results. Gestational anemia is associated with threatened miscarriage (Odds Ratio (OR) 3.496; 95% CI 2.013–6.072), chronic placental insufficiency (OR 1.907; 95% CI 1.025–3.548), delivery by cesarean section (OR 2.729; 95% CI 1.651–4.502), increased infectious morbidity in pregnant women (OR 1.079; 95% CI 1.025–3.548) and insufficient lactation (OR 1.990; 95% CI 1.209– 3.277). Treated anemia during pregnancy is not associated with low birth weight and low weight of 6 and 12 months old children. 8.6% of 6 months old children suffered from iron deficiency anemia, which is two times lower than in the group without anemia (p=0.007). The frequency of iron deficiency anemia did not differ in 12 months old children (р=0.543). Conclusion: Iron supplementation reduces the negative impact of anemia on child’s health, including anthropometric indicators, iron stores, and risk of infectious diseases. The indirect effect is maintained through the adverse course of the perinatal period and the low duration of lactation.

A two-crystal fibre-pigtailed acousto-optic frequency shifter has been developed and investigated. An optimal configuration of acousto-optic cells is chosen. A two-crystal acousto-optic frequency shifter of 785-nm laser radiation in the range from 156 to 196 MHz, with single-mode polarisation maintaining fibres at the input and output, is described. Some recommendations are given how to improve the shifter transmission coefficient and increase the frequency shift range.

An angular aperture of an acousto-optical filter upon a linear frequency-modulated (chirp) control signal has been experimentally studied for the first time. The results of studying the spectral and angular dependences of the spectral transmission function of a filter upon a frequency modulation have shown the possibility of an efficient increase of the output optical signal. The value of the optical signal was increased by 2000 times using the selected design of the acousto-optical filter. This makes it possible to obtain a gain in the measurement time or in the value of the detected optical signal. Such an increase of the output signal upon a chirp control signal is provided by the increase of the angular aperture and broadening of the spectral transmission bandwidth together with the required proportional increase of the control signal power.

Acousto-optic modulators/frequency shifters based on TeO2 crystals with single-mode optical fibers supporting and not supporting polarization for collimated and focused light beams at radiation wavelengths of 785, 1064, 1550 nm have been developed, produced and experimentally investigated. The mechanisms of formation and methods of expanding the working band of the modulator are determined. A double-crystal acousto-optic laser emission frequency shifter with an working bandwidth of ≈40 MHz has been created. Single-crystal modulators based on collimated beams with a frequency band of ≈10 MHz are considered. A single-crystal modulator with a focused light beam with a switching time of ≈ 18 ns and an extended reception band of ≈ 40 MHz is investigated. It is shown that a light beam focusing makes it possible to implement a modulator with a minimum switching time of ≈ (2-3) ns. This value is limited by electrical breakdown of the ultrasonic wave transmitter.

A two-crystal high-transmission acousto-optic monochromator is developed and studied. The transmittance of the monochromator can substantially be increased and the scheme can be simplified using the reflection from a face of the acousto-optic cell as a separating polarizer. The intervals of parameters of acousto-optic interaction (angles and wavelengths) that correspond to high efficiency of the monochromator are found. Characteristics of two high-transmission monochromators with different parameters of the acousto-optic interaction are determined.

Iron-deficiency anemia is a common and, despite the available wide range of iron preparations, unsolved problem in pediatric practice. This is often associated with inadequate diagnosis in primary health care, which is due to both objective problems and underestimation of the seriousness of sequels of iron deficiency. This review gives data on the epidemiology of iron-deficiency anemia in the Russian Federation and worldwide, existing approaches to denning concepts, such as anemia, iron deficiency, and iron deficiency anemia in children, and possible diagnostic methods from the simplest to high-tech.

Urinary tract infections remain a common childhood disease. Whether furamag (furazidine potassium) potassium might be used as starting monotherapy for uncomplicated urinary tract infection in an outpatient setting was assessed. The investigation enrolled 122 children aged 3 to 15 years with an established diagnosis of urinary tract infection, who were followed up in the outpatient setting, and divided into two groups. Group 1 (n=62) received oral antibiotic therapy with protected penicillin with subsequent switch to uroseptics. Group 2 (n=60) had furamag monotherapy. After 10 days of treatment the therapeutic efficiency had no significant difference in both groups, the disappearance rates of clinical and laboratory markers for the infection were comparable. The use of furamag as monotherapy for uncomplicated urinary tract infection can be an alternative to antibiotics in children older than 3 years of age.

Potassium-yttrium tungstate is analyzed as material for modulation of high power laser beams. It is found two promising AO modulator configurations: first of them provides the highest diffraction efficiency for linear polarized radiation, while the second one is capable to modulate random polarized radiation.