Characterization of biocenoses in the storage reservoirs of liquid radioactive wastes of Mayak PA. Initial descriptive report

As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for (90)Sr and (137)Cs, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007-2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure.

Short-period multilayer X-ray mirrors

Multilayer structures with short periods have been systematically investigated using a tunable soft X-ray synchrotron, BESSY II, and X-ray tube radiation. Multilayer X-ray mirrors of W/B(4)C, W/Sc, Mo/B(4)C, Mo/C, La/B(4)C, Cr/C and Cr/Sc, with periods from 0.8 nm to 3.5 nm and number of periods up to 300-400, were constructed and investigated. The high reflectivity and spectral resolution of the mirrors allow them to be used to create multimirror systems for X-ray diagnostics of high-temperature plasma, for X-ray astronomy and microscopy.

[Phytoplankton in reservoir R-11 of Techa reservoir cascade of Industrial Association "Maiak"]

Phytoplankton of reservoir R-11 was investigated at vegetative seasons of 2007 and 2008. R-11 is a locking reservoir in the cascade of Mayak PA reservoirs. The specific activity in water of R-11 ranged from 0.9 to 1.8 kBq/dm for 90Sr and from 0.98 to 3.97 kBq/dm3 for 137Cs; in bottom sediments it ranged from 20 to 400 kBq/kg for 90Sr and from 0.35 to 220 kBq/kg for 137Cs. Concentration of SO4- exceeded the maximum permissible concentration for fishing reservoirs in 5-7 times. The content of 90Sr in the phytoplankton has made 400 kBq/kg (for dry weight), and 137Cs--2.20 kBq/kg (for dry weight). The absorbed dose of irradiation for the phytoplankton calculated under the content of 137Cs and 90Sr in water and in phytoplankton (the external irradiation from activity of bottom sediments was not considered) has made 901 mGy per year. Altogether the phytoplankton of reservoir R-11 included 107 species. Such species of Cyanobacteriae as Oscillatoria agardhii Gom. was the dominant in phytoplanktonic community. Another Cyanobacteriae, Lyngbya limnetica Lemm. and Aphanizomenonflos-aquae (L.) Ralfs. acted the most important part in a complex of species-subdominants. According to quantitative development of the phytoplankton the reservoir R-11 can be classified as P-mezosaprobe waters.

Basic therapeutic approaches to the management of hematology/oncology patients with new coronavirus infection (COVID-19)

In December 2019, cases of severe respiratory infection were reported in Wuhan, China. The disease was caused by a new, previously undescribed coronavirus, structurally similar to the then known SARS-CoV virus. The World Health Organization has named the new virus SARS-CoV-2 and the disease it causes COVID-19. The problem of COVID-19 is exacerbated by the rapid spread of the SARS-CoV-2 virus and the development of life-threatening complications, the main of which is pneumonia. Due to the severity of the condition, from 5 to 10 % of patients are treated in intensive care units.

SARS-CoV-2 initially attacks the respiratory system and causes symptoms such as fever, vomiting, headache, dizziness, general weakness, and diarrhea. Then these symptoms intensify in different directions, and the disease can often lead to death.

Initially, only a few methods of symptomatic treatment were available and clinical trials of drugs that had previously shown their effectiveness against infection with the MERS-CoV and SARS-CoV viruses began. Temporary recommendations have appeared suggesting the use of some drugs both in monotherapy and in combination.

In patients with hematologic malignancies, the immune response to the SARS-CoV-2 coronavirus is significantly reduced, which explains the high mortality rate (up to 38 %) of these patients hospitalized for SARS-CoV-2 infection. Recently, antiviral drugs and monoclonal antibodies have become available for pre- or post-exposure prophylaxis, as well as for early treatment of COVID-19. These treatments should be offered to patients at high risk of severe COVID-19 and to those who have not responded to vaccination. However, as changes in the genetic structure of the virus accumulate, some treatments may lose their clinical effectiveness against new variants.

The combination of hematological malignancies and new coronavirus infection causes a more severe course of COVID-19 compared to the population and high mortality. Factors for an unfavorable prognosis for new coronavirus infection in patients with hematological malignancies include age over 60 years, a high comorbidity index, diagnoses such as acute leukemia, especially acute myeloid leukemia and myelodysplastic syndrome, disease status (relapse, progression, as well as newly diagnosed acute leukemia), severe COVID-19, agranulocytosis (myelotoxic or tumor).

[Evaluation of the toxic properties of cyanobacteriae of the Shershnevo water storage basin in the Chelyabinsk Region]

The toxic properties of cyanobacteriae of the Shershnevo water storage basin have been studied. Over almost the whole vegetative period of 2005, the cyanobacteriae of the Shershnevo water storage basin may be characterized as high toxic (when intraperitoneally injected to male CBA mice, LD50 was less than 100 mg/kg). There were no interspecific differences between the noninbred animals in cyanotoxin susceptibility. Gender differences were revealed in cyanotoxin susceptibility in CBA and noninbred albino mice: quantitative differences in LD50 (males/females) were 1.34 in CBA mice and 1.3 times in noninbred albino mice. The cyanobacteriae of the Shershnevo water storage basin were found to have an irritating effect on the skin and ocular mucosa. It is suggested that the toxins of Shershnevo water storage basin cyanobacteriae may have a damaging effect on human beings.

[Functional state of a solitary kidney after nephrectomy for renal cancer]

INTRODUCTION

The outcome of surgical treatment of renal cancer depends not only on cancer-specific survival, but also on the degree of loss of renal function, which often develops after surgery, especially radical nephrectomy.

AIM

To study the features of functional changes in a solitary kidney as a compensation mechanism after radical nephrectomy for renal cancer.

MATERIALS AND METHODS

The functional state of a solitary kidney in 36 patients with renal cancer who undergone to radical nephrectomy was evaluated. There were 20 and 16 women. The mean age was 59.0+/-10.8 years (from 39 to 76 years). The size of the tumor was in the range of 7.0-12.0 cm. All patients with a solitary kidney underwent a follow-up examination 3 months after surgery, including measurement of peripheral blood pressure with calculation of mean dynamic pressure, renal ultrasound, calculation of glomerular filtration rate (GFR), renal doppler ultrasound, determination of serum fibrinogen and fibrin monomers, and microscopy of the bulbar conjunctiva. Patients who had pathological abnormalities during the examination were prescribed reno-cardioprotective drugs, including perindopril in a titrated dose, apixaban 5 mg a day as thromboprophylaxis and for improvement of the flow properties of blood for a period of 3 months with re-evaluation of the above parameters.

RESULTS

In 61.1% of patients after radical nephrectomy, on 2-4 postoperative days, there was a tendency to increase blood pressure compared to baseline values (p<0.05). By the seventh day after the procedure, the volume of the contralateral kidney increased on average by 16% (from 110.4+/-11.2 cm3 to 132.4+/-4.8 cm3, p<0.05). After radical nephrectomy, a decrease in GFR was detected in 33 cases (91.7%; p<0.05). Renal doppler ultrasound showed a moderate increase in linear blood flow, the resistance index in the main renal artery, and a decrease in the pulse index in the segmental and arcuate arteries. The microscopy of the bulbar conjunctiva in 83.3% of patients revealed changes in the microcirculatory bed, including narrowing of arterioles, dilation of venules, a decrease in venular and capillary blood flow. After 3 months of reno-cardioprotective therapy, it was revealed that the target values of blood pressure (<130/85 mm Hg) were achieved with an average dynamic blood pressure of 93.4+/-2.6 mm Hg. In addition, a decrease in creatinine to an average of 106.2+/-6.4, fibrinogen and fibrin monomers to subnormal values of 3.2+/-0.2 g/l and up to 8.1+/-0.5x10-2 g/l, respectively were seen. Renal hypertrophy according to ultrasound examination was preserved with a mean kidney volume 119.7+/-3.6 cm3. Disturbances in peripheral microcirculation according to the microscopy of the bulbar conjunctiva was assessed as moderate.

CONCLUSION

The development of CKD in patients with a solitary kidney is accompanied by a structural reorganization of the organ with an increase in blood pressure, an increase in its volume, a decrease in function, microcirculatory disorders and hypertensive nephropathy. Considering the prognostic significance of changes in the solitary kidney, it is important not only to control the functional parameters, but also to include reno- cardioprotective therapy as a standard, since it contributes to the preservation of the renal function and prevents the rapid progression of CKD. Thus, medical and social rehabilitation of patients with a solitary kidney is required. However, it is currently cannot be considered comprehensive.

Antibiotic Resistance of Klebsiella Pneumoniae Strains Isolated from the Blood of Patients with COVID-19

A retrospective analysis of case histories and the results of microbiological blood tests of patients with coronavirus infection COVID-19 who were treated in the infectious diseases hospital of the city clinical hospital №52 in Moscow in 2020 was carried out. The sensitivity to the main antibacterial agents was determined for each isolate of Klebsiella pneumoniae, the phenotype of each pathogen was characterized (MDR, XDR, PDR). The results of the study were statistically processed and presented in the form of a register of bacteremia cases. Most pathogens (79%) were isolated from the blood of patients who were treated in intensive care units. Klebsiella pneumoniae ranked first in the structure of bacteremias, the frequency of occurrence of the pathogen was 41,1% (282/686). Only 4% of Klebsiella pneumoniae isolates were sensitive to antibiotics; the phenotypes of antibiotic-resistant strains were MDR – 16%, XDR – 76%, PDR – 4%. Most of the isolated Klebsiella pneumoniae strains were carbapenem-resistant (85,4%), 11,1% were colistin-resistant, 10,6% of the isolates were extended spectrum β-lactamase producers.

[Effect of toxins of cyanobacteria of the Microcystis genus from the Shershnevo Reservoir on DNA, cell cycle, and apoptosis of bone marrow cells in CBA mice]

The effect of toxins of a Cyanobacterium sample of the Shershnevo Reservoir on DNA, which was presented by cyanobacteria of the Microcystis genera, on the bone marrow of male CBA mice (whose age was 3 months and weight 24 g) was evaluated. With intraperitoneal administration, LD50 and LD16 of this sample for male CBA mice were 48.4 and 42.1 mg/kg, respectively. Administration of Microcystis cyanobacterial sample from the Shershnevo Reservoir in doses of 1/10 of LD16 and 1/2 of LD16, and LD16 was found to cause a dose-dependent reduction in the number of bone marrow nucleated cells, a dose-dependent increase in the rate of cell apoptotic death, a reduction in the duration of a cell cycle (within the first 12 hours), which gave way to an increase in the duration of the cycle 24 hours after administration, a dose-dependent increase in the frequency of micronuclei in the murine bone marrow eryphrocytes, and a dose-dependent decrease in the polychromatophil/normochromatophil ratio in the murine bone marrow.

[The assessment of modulated radiofrequence electromagnetic radiation on cognitive function in rats of different ages]

The modulated radiofrequence electromagnetic radiation influence on cognitive function of male uninbred Wister rat exposed at the age of sexual maturation (2 months) and at the age of morphofunctional maturity (3.5 months) was examined. Animals were subjected to pulse electromagnetic radiation (925 MHz) modulated as a GSM standard with the power density 1.2 mW/cm2 for 10 minutes every day for 12 days. At day 8 of exposure the cognitive function were examined with the Morris water maze. In the result of investigation it was determines that modulated radiofrequence electromagnetic radiation at the sexual maturation age did not affect the spatial learning and improve the visual orientation performance. Modulated radiofrequence electromagnetic exposure of animals at the sex maturity age did not affect the visual performance and improve the spatial performance of male rats.

[Assessment of radiation exposure level for hydrobionts in some special industrial ponds at the "Mayak" PA]

Evaluation of the radionuclide content in the ecosystem components (water, sediments, aquatic organisms) of industrial reservoirs-storages of liquid radioactive waste of the "Mayak" PA (reservoirs R-4, R-10, R-11, R-17, R-9) and the estimation of the absorbed dose rate in aquatic organisms of these reservoirs using the software package ERICA Assessment Tool 1.0 May 2009 have been performed. Gradient of the absorbed dose rate for the detected taxonomic groups of hydrobionts in the series of the studied reservoirs R-11 --> R-10 --> R-4 --> R-17 --> R-9 was almost equal to one order of magnitude. The estimated absorbed dose rate for phytoplankton ranged from 5.4 x 10(0) mGy/day (R-11) to 4.0 x 10(4) mGy/day (R-9), for zooplankton--from 6.4 x 10(-1) mGy/day (R-11) to 3.8 x 10(3) mGy/day (R-9), for zoobenthos (chironomids)--from 5.6 x 10(0) mGy/day (R-11) to 1.1 x 10(3) mGy/day (R-17), for fish (roach)--from 8.0 x 10(-1) mGy/day (R-11) to 1.9 x 10(1) mGy/day (R-4).

Benefits of early antifungal therapy in hematology patients

Invasive fungal infections (IFIs) are a serious threat to patients with hematological diseases. These infections are characterized by high mortality and lead to significant financial costs for treatment. The most common pathogens of IFIs are Aspergillus spp. and Candida spp., but in recent years, cases of infections caused by rare pathogens have become more frequent. Diagnosis of IFIs and choice of treatment remain challenging due to the nonspecificity of symptoms and the diversity of clinical cases. In this regard, the problem of start time and choice of antifungal therapy remains of current interest. This review briefly describes diagnostic criteria, challenges associated with IFIs diagnosing, provides evidence for empiric and preventive strategies as two early treatment approaches, and examines the impact of therapy initiation on patient outcomes. Treatment of IFIs in hematologic patients should be individualized. At the same time, early administration of therapy with broad-spectrum drugs for febrile neutropenia and parallel diagnostic measures can improve treatment outcomes. There is a lack of current data on the benefits of specific treatment strategies, highlighting the need for further research.

Humanized Mice as a Model to Assess the Response of Human Hematopoietic Stem Cells to Irradiation

NOD SCID mice were humanized by transplanting human hematopoietic cells isolated from umbilical cord blood. A dose-dependent death of hematopoietic cells and their subsequent recovery were shown after acute external γ-irradiation in the model of humanized mice. The proposed approach can be used for preclinical studies of radioprotective agents and for assessment of the impact of adverse factors on the survival rate and functional properties of human hematopoietic stem cells in vivo.