Vol 45, No 2 (2017)


On the 80th anniversary of Gennadiy Alekseevich Onoprienko


Almanac of Clinical Medicine. 2017;45(2):78
pages 78 views


Сurrent concepts in physiological and reparative osteogenesis

Onoprienko G.A., Voloshin V.P.


Studies conducted in the recent years by biologists strongly suggest that physiological and reparative osteogenesis, as well as of the functional, adaptive, and post-traumatic reconstruction of bone tissues are based on common and stereotypical molecular and cellular mechanisms. Our experimental studies have shown that all stages of the bone microstructure morphogenesis are synchronously and continuously associated with focal and stereotypical angiogenesis (capillarogenesis). A powerful factor in the implementation of reparative osteogenesis is the osteoinductive interaction of the ends of the damaged bone segments, which positively shows itself even in cases of large diastasis between the fragments (provided that the fragments are steadily fixed). After any kind of stable osteosynthesis, by ensuring the stability of the bone fragments for the entire period of consolidation, an endosteal cortical bone regeneration by direct osteogenesis (i.e. without fibro-cartilaginous tissue) is observed in the minimum amount at the shortest time period. Periosteal bone formation in this case is actually a reserve source of bone formation, which becomes effective during insufficiently stable conditions. The instability of the bone damage area particularly that of the metal implants results in the most severe destructive consequences. 

Almanac of Clinical Medicine. 2017;45(2):79-79
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Matrix metalloproteinases 2, 7, 8, 9 and their type 1 tissue inhibitor in serum of renal cancer patients: clinical and pathologic correlations

Gershtein E.S., Mushtenko V.V., Korotkova E.A., Bezhanova S.D., Morozov A.A., Alferov A.A., Kazantseva I.A., Kushlinskii N.E.


Background: The cause of late diagnosis of renal cancer lies in its durable, almost asymptomatic course. Due to the use of antiangiogenic therapies much progress has been made in its treatment in recent years. Yet, many questions concerning the diagnosis, prognosis and prediction of the efficiency of targeted therapy remain unsolved. Therefore, exploration of new renal cancer molecular markers, especially those related to its angiogenic and invasive activities, are still on the agenda. Such markers include the family of matrix metalloproteinases (MMPs) that degrade the majority of extracellular matrix components and are involved at all stages of tumor progression. Aim: Comparative evaluation of MMP2, 7, 8, 9 and type 1 tissue inhibitor (TIMP-1) levels in serum of healthy individuals and patients with renal cancer or benign renal tumors, analysis of their associations with the main clinical and pathologic characteristics of the disease. Materials and methods: We examined 99  renal cancer patients (of those 94 with primary tumor and 5 at progression) and 10 patients with benign renal tumors. The control group included 97 healthy individuals. Levels of the proteins studied were measured using respective direct ELISA kits (Quantikine®, R&D Systems, USA). Results: MMP-7, MMP-8 and TIMP-1 levels in the sera of renal cancer patients were significantly higher than in the control group and in benign renal tumor patients. MMP-2 and MMP-9 levels did not differ significantly between the study and control groups. At MMP-7 cut-off level of 3.0  ng/mL, its diagnostic sensitivity for primary renal cancer was 84%, specificity in relation to “healthy” control – 87.5%, in relation to the pathologic control (healthy donors+benign renal tumor patients) – 73%. The best sensitivity: specificity ratio for TIMP-1 was 67 and 65% at the cut-off level of 315 ng/ml. No cut-off value with acceptable sensitivity: specificity ratio was found for MMP-8. Serum levels of all these 3 markers were positively associated with disease stage and TNM indices; MMP-7 and TIMP-1 levels also increased with lower differentiation grade. In 5 patients evaluated at disease progression the levels of all the markers studied were markedly higher than in the primary patients, and exceeded the estimated cut-off values. Conclusion: MMP-7 should be regarded as the most promising serological renal cancer marker; its serum levels exceed the cut-off value even in 84% stage I patients. TIMP-1 has acceptable sensitivity (70% and above) only from stage II renal cancer onwards, while MMP-8 levels are increased only at stage III–IV of the disease.

Almanac of Clinical Medicine. 2017;45(2):94-101
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Free light chains of immunoglobulins in the diagnosis and prognosis of multiple myeloma

Lyubimova N.V., Timofeev Y.S., Votyakova O.M., Kushlinskii N.E.


Background: Analysis of free light chains of immunoglobulins (FLC) in the serum is an effective method in the diagnosis of multiple myeloma. Plasma cells produce two types of FLC: κand λ-FLC. FLC, which are not incorporated into monoclonal intact immunoglobulins, are released into circulation, and then are filtered and reabsorbed in kidneys depending on their molecular weight. Circulating FLC commonly form homodimers, known as Bence-Jones protein, which is a biomarker of Bence-Jones multiple myeloma. According to the international guidelines, the ratio κ/λ FLC is an important diagnostic criterion of multiple myeloma. Aim: To evaluate the diagnostic and prognostic value of serum FLC in multiple myeloma patients. Materials and methods: We examined 118 patients with multiple myeloma, admitted to the Department of Hemoblastosis Chemotherapy of N.N. Blokhin Russian Cancer Research Center from 2010 to 2016, and 68 healthy men and women. Serum concentrations of FLC were measured with an immunoturbidimetric method using the test-system Freelite Human Lambda and Freelite Human Kappa (Binding Site Inc.). Results: The levels of monoclonal κor λ-FLC in patients with G-, A-myeloma and Bence-Jones multiple myeloma were significantly higher than those in the control group (p < 0.005). The diagnostic sensitivity of quantification of FLC and their ratio was 87.3% and 89.8%, and in combination with the use of immune electrophoresis it was close to 100%. Analysis of progression free survival and overall survival showed significant differences (p < 0.04) between the groups of patients according their κ/λ FLC ratio. The basal value of κ/λ FLC ratio of less than 0.04 and more than 140 was a  predictor of unfavorable outcome. Conclusion: The inclusion of the determination of serum FLC into the assessment plan of patients with suspected monoclonal gammapathy makes it possible to increase diagnostic sensitivity of the available methods for paraprotein determination, as well as to monitor patients with non-secreting multiple myeloma. FLC analysis in multiple myeloma patients acquires special significance in the prognosis of remission, since the antitumor response based on their measurement is seen earlier than that based on the results of standard immunochemistry studies.

Almanac of Clinical Medicine. 2017;45(2):102-108
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Evaluation of the lymphocyte interphase nuclei phenotype by quantitative phase imaging (QPI) in patients with endometrial ovarian cysts

Gasparyan S.A., Popova O.S., Vasilenko I.A., Khripunova A.A., Metelin V.B.


Rationale: Ovarian endometriosis is a progressive disease with growing prevalence and severity. Therefore, the development of robust non-invasive laboratory screening methods for early diagnosis on the out-patient basis seems quite relevant. Aim: To assess a potential of the quantitative phase imaging technique for early diagnosis of ovarian endometrial cysts and post-operative relapses of the disease. Materials and methods: We analyzed 1578 nuclei of the peripheral blood lymphocytes from 82 patients with ovarian endometrial cysts, aged 21 to 37 years (mean age 26.4 ± 3.6 years). The patients were follow-up in a gynecology out-patient clinic (the town of Yessentuki, Russia). Assessments were made longitudinally, i.e., before a laparoscopic cystectomy, at 6 and 12 months in the post-operative period with or without treatment with dienogest-containing agents. Morphological and functional status of the nuclei from the peripheral blood lymphocytes was assessed in the real-time mode by quantitative phase imaging (QPI) with the phase-interference microscopy module of the Bioni hardware and software complex (Westgrade Ltd., Moscow) for clinical and laboratory diagnostics, and the morphodensitometric segmentation technology. Results: The comparative analysis of morphometric parameters of CD3+ cells taken from peripheral blood of healthy non-pregnant women and patients with ovarian endometrial cysts before surgery showed a significant increase of the calculated functional activities of the lymphocyte nuclei (0.898 vs 0.783, p < 0.05). Assessment of changes overt time in the differential diagnostic criteria of the nuclear response in the peripheral blood lymphocytes from patients with endometrial ovarian cysts showed the following. Compared to the parameters obtained before treatment, at 6 and 12 months of the post-operative period the relative intensity of nuclear segments (ΔI) decreased by 10.3 and 14.7, 10.6 and 12.9% in the group treated with and without dienogest, respectively. Relative distance between the centers of the nuclear segments (ΔL) demonstrated a trend towards an increase by 0.6 and 0.9, 4.2 and 2.1%. The numbers of nuclear segments increased by 18.3 and 13.4, 27.4 and 16.9%, whereas the nuclear perimeter decreased by 13.9 and 12.6, 11.9 and 7.8%, respectively. In the patients treated with dienogest, the rate of non-relapse at 6 and 12 months of the follow-up was 100%, whereas in the patients without dienogest therapy, 97.5 and 93.5%, respectively. Discussion: Interphase chromatin is a unique biosensor of the early abnormalities in a lymphoid cell. Modification of its structure and packaging density not only indicate changes of the morphofunctional status of the lymphocyte, but can be projected to the body as a whole and used for early pre-clinical diagnosis, assessment of severity of the pathological process and prediction of the outcome in various critic states. Conclusion: Practical implementation of QPI for clinical monitoring of patients with ovarian endometrial cysts makes it possible to obtain important information on the cell immunity in real time. It opens new opportunities to assess the efficacy of treatment and rehabilitation activities, as well as for early pre-clinical diagnosis of relapsing disease.


Almanac of Clinical Medicine. 2017;45(2):109-117
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Seborrheic keratosis: clinical characteristics and an association with the β-genus human papillomavirus

Pisklakova T.P., Kostenko E.I., Telesheva L.F.


Background: Seborrheic keratosis is a  common benign tumor of unclear etiology. Aim: To study associations between clinical characteristics of seborrheic keratosis and its course with quantitative parameters of the β-genus human papillomavirus (β-HPV). Materials and methods: The main study group included 91 patients with seborrheic keratosis (29 male and 62 female), aged 40 to 75  years (mean ± SD, 59.2 ± 6.4 years). The control group included 30 healthy individuals persons aged 40 to 70 years (mean 57.6 ± 4.1 years). The diagnosis of seborrheic keratosis was confirmed by dermoscopy and pathomorphological assessment, with 100% of patients having the acanthotic type of seborrheic keratosis. HPV was identified by polymerase chain reaction with hybridization fluorescent detection in real time mode with use of three oligonucleotide systems for detection of HPV genus β1 (subtypes 5, 8, 12, 14, 19, 21, 25, 36, 47); β2 (subtypes 9, 15, 17, 22, 23, 37, 38, 80), and β3 (subtypes 49, 75, 76). Results: The most frequent clinical type of seborrheic keratosis was the maculopapular one (61/91 patients, 67%) localized mainly on head, neck, anterior and posterior trunk. β-HPV was found in 88.8% biopsy samples taken from the seborrheic keratosis areas in 24 of 27 patients and in 66.6% biopsy samples taken from the normal skin areas of the same patients (р = 0.04). This is significantly more frequent that the HPV contamination among healthy individuals, which was 28.7% (р = 0.02). Mixed association of β-HPV was also more frequent in the HPV-positive patients (21/24, or 83.3%; compared to the control group, р = 0,00001). The maximal (significant) viral load was found in the subgroup of seborrheic keratosis patients with the number of proliferative lesions of 10 and more (4.08 ± 0.3 lg/105 tо 5.7 ± 0,3 lg/105). Conclusion: The maculopapular type of seborrheic keratosis is characterized by mixed HPV β1, β2, β3 infection found in 77.7% of cases irrespective of the number of proliferative lesions. It could be hypothesized that multiple seborrheic keratosis (more than 10 lesions) develops in simultaneous presence of HPV β1, β2, β3 and is associated with a  higher probability of new seborrheic keratosis lesions on intact skin. 

Almanac of Clinical Medicine. 2017;45(2):118-126
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Phenotypic characterization of the biological properties of coagulase-negative staphylococci isolated in a cardiac surgery department

Granichnaya N.V., Zaitseva E.A., Bondar V.Y.


Rationale: A  significant proportion of post-operative infectious complications in cardiovascular surgery is caused by Staphylococcus spp, with an increasing role of Staphylococcus epidermidis. Aim: To identify biological characteristics of coagulase-negative staphylococci isolated from various biotopes in a cardiac surgery department, in order to assess their pathogenic potential. Materials and methods: The study was performed with Staphylococcus isolates (n = 73) obtained in a cardiac surgery department in 2015–2016. Biochemical identification of the cultures was done with the use of Vitek 2  compact microbiological analyzer (BioMerieux, France) and test systems Staphytest (ERBA Lachema, Czech Republic). The biological properties of staphylococci were assessed by classical microbiological techniques. Statistical analysis was done with the Microbe-2  software package. Results: S. aureus and 6 strains of coagulase-negative staphylococci with predominance of S.  epidermidis were isolated in the department of cardiac surgery. In most cases S.  epidermidis was isolated from post-operative wounds (n = 16, 30.8 ± 6.4%) and environmental swabs (n = 11, 21.1 ± 5.7%). All S.  epidermidis studied (n = 52) hydrolyzed maltose with formation of the acid without gas, could ferment glucose and tregalose, and were lacking β-galactosidase (except the cultures isolated from post-operative wounds). They also could not degrade mannitol in aerobic environment (excluding staphylococci isolated from the environmental objects and from the medical staff). S.  epidermidis displayed variable biochemical activity towards lactose and saccharose. Hemolytic activity (more often of the β-type) was characteristic for 69.2 ± 6.4%  of S.  epidermidis cultures. The majority of cultures (92.4 ± 3.6%) displayed proteolytic activity irrespective of the type of staphylococci and the source of isolation. Lipolytic activity was more frequent in staphylococci isolated from clinical materials (airway secretions of the medical personnel [9/10  cultures], patients [9/10  cultures] and post-operative wounds [16/20 cultures]), than in those isolated from the environmental objects. There was a direct significant correlation between the lipase activity and the presence of β-galactosidase (φ=0.40), lipase and proteolytic activities (φ=0.33), β-galactosidase and gelatin liquation (φ=0,65), hemolytic and proteolytic activities (φ=0.37). Conclusion: S. epidermidis was the most prevalent pathogen in all ecotopes of the department of cardiac surgery. Biochemical properties of coagulase-negative staphylococci and their fermentative activity related to factors of pathogenicity were different depending on the site of isolation. This illustrates their contribution in the development of inflammation in a given biotope.

Almanac of Clinical Medicine. 2017;45(2):127-132
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Iron-dependency of biological properties of Candida albicans

Leonov V.V., Mironov A.Y.


Background: Candidal infections occur in individuals with humoral or cell immunity deficiency. Any disorders of iron metabolism promote immune deficiency and abnormal sensitivity to infections. Potential modification of biological properties of Candida spp. in disorders of iron metabolism has not been discussed. Aim: To clarify the effects of iron metabolism disorders on the modification of biological properties of C.  albicans. Materials and methods: Growth kinetics of reference strain (24433 АТСС) and clinical isolates of C.  albicans (n = 20) depending on the concentration of Fe2+ ions in the broth and serum of blood donors with various types of iron metabolism (n = 2) was studied by turbidimetry. We also assessed the expression of the adhesion gen (als3), hemolytic phospholipase C genes (plb1, plb2, plс) and aspartic protease gene (sap1) in serum of donors with various iron levels. Results: Growth parameters of all C. albicans strains studied depends on the iron levels in the medium. The calculated constant of affinity to Fe2+ (Ks) for C. albicans strains was in the range from 179.5 to 1863.3 μM. Clinical isolates are more iron-dependent (179.5 < K< 1000 μM), compared to the reference strain ATCC 24433 (K= 1199.5 ± 28.3 μM). The optimal concentration of iron for the growth in the broth is 30 to 50 μM. The serum from individuals with normal iron metabolism inhibits the growth activity of C. albicans and is associated with overexpression of all virulence genes studied. Incubation of C.  albicans with iron-deficient and iron-loaded sera results in an increase in the growth rate up to 0.017 h-1 and 0.012 h-1, respectively, but is associated with a  reduction in expression of the major virulence genes. Conclusion: Biological properties of C. albicans are modified depending on the iron metabolism of the host. In those with normal iron metabolism, immune system suppresses Candida growth. Excess iron levels may promote candidiasis, whereas in iron deficient states the outcome of infection depends on the immune status of the host.

Almanac of Clinical Medicine. 2017;45(2):133-137
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Antibacterial resistance of Enterococcus spp. isolated from commercial poultry of the Russian Federation farms in 2013–2016, and identification of vancomycin resistance genes

Svetoch E.A., Teymurazov M.G., Tazina O.I., Abaimova A.A., Lev A.I., Astashkin E.I., Leonova E.S., Kartsev N.N., Detushev K.V., Eruslanov B.V., Dyatlov I.A., Fursova N.K.


Rationale: Enterococci are the leading cause of a number of nosocomial and community-acquired human diseases. In the last decade, these pathogens are becoming resistant to antibacterials, including vancomycin. Multidrug-resistant enterococci have been also isolated from agricultural animals in many countries worldwide, which raises concern of scientists because of possible horizontal transfer of resistance genes. Aim: To assess antibacterial sensitivity of Enterococcus spp. isolates collected from the poultry in the Russian Federation from 2013 to 2016, and to identify vancomycin-resistance genes in their genomes. Materials and methods: Eighty-seven enterococci isolates belonging to E.  faecalis (n = 47, 54%), E.  faecium (n = 25, 28.7%) and other species (n = 15, 17.2%) were collected from clinical samples of 297 heads of poultry (liver, lungs, heart, spleen, contents of the nasal and sinus cavities) from 17  poultry farms of the Northwest, Central, Volga, Ural and Southern Federal districts of the Russian Federation. Sensitivity of enterococci to antibacterials was determined by disk-diffusion and broth microdilution methods. Vancomycin resistance genes van was detected by polymerase chain reaction with specific primers. Results: Most enterococci isolates were resistant to erythromycin (74/87, 85.1%), gentamicin (70/87, 80.5%), ceftriaxone (61/87, 70.1%), ciprofloxacin (56/87, 64.4%), tetracycline (57/87, 65.5%), and rifampicin (48/87, 55.2%), fewer ones to trimethoprim (38/87, 43.7%), ampicillin (28/87, 32.2%), linezolid (15/87, 17.2%) and chloramphenicol (5/87, 5.7%). The vanC type genes (vanC1 and vanC2/3) were identified in 10  isolates. Vancomycin minimal inhibitory concentrations for these isolates were 2 to 8  mg/L. E. faecium with vanC1 gene was isolated from poultry probably for the first time ever. Conclusion: Commercial poultry in the Russian poultry farms is an important reservoir and source of antibiotic-resistant enterococci populations, including enterococci carrying vanC1 and vanC2/3 vancomycin resistance genes. 

Almanac of Clinical Medicine. 2017;45(2):138-146
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Specific biological properties of Listeria innocua spp. isolated in Primorye Territory

Zaitseva E.A.


Rationale: Most cases of listeriosis are caused by the pathogenic Listeria monocytogenes. Some cases of isolation of L.  innocua with pathogenicity factors from foods have been published, as well as on the cases of the disease in humans caused by this species. Aim: To assess biological properties including potential pathogenicity of L.  innocua, isolated from food and environmental objects. Materials and methods: We performed microbiological study of L. innocua cultures isolated from foods (n = 35) and environmental objects (n = 15) on the territory of Primorye Territory (Russian Federation), as well as assessment of their sensitivity to antibiotics. Results: The studied L.  innocua cultures showed stable phenotypic features of their biological properties, such as morphology, typical colony growth on the medium with characteristic odor of fermented milk, blue or blue-green luminescence induced by inclined light, presence of catalase activity and absence of the oxidase activity. Only 38 ± 6.9% of L.  innocua demonstrated movements at T 22 °С. L.  innocua cultures did not ferment mannitol (100% of cultures); they degraded ramnose to its acid without gas (70 ± 6.5%) and degraded xylose (42.8 ± 7%). Listeria isolated from vegetables and environmental objects could ferment ramnose (92.8 ± 7.2% of the studied cultures) and xylose (28.5 ± 12.5%) more frequently than L. innocua isolated from meat and fish foods. L.  innocua demonstrated variable biochemical activities towards mannose (92 ± 3.8%), saccharose (85.7 ± 7.8%) and melesitose (76.2 ± 9.5%). L. innocua cultures with hemolytic activity (34 ± 6.7%) (α or β  type) were isolated, more commonly from fish products. All Listeria irrespective of their isolation source showed lipase activity. L.  innocua cultures from foods and environmental objects were highly sensitive to antimicrobials from the following classes: penicillins (ampicillin, carbenicillin, combined amoxicillin and clavulanic acid), aminoglycosides (gentamycin, amikacin), carbapenems (meropenem), and fluoroquinolones (ofloxacin). Conclusion: Some biological properties of L. innocua were variable depending on the source of isolation. Isolation of Listeria with atypical properties in theterritory of Primorye Territory requires that these microorganisms should be studied in more detail. 

Almanac of Clinical Medicine. 2017;45(2):143-159
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Adhesivity оf standard and biofilm cultures of toxigenic Corynebacterium diphtheriaе strains

Kharseeva G.G., Alieva A.A., Sylka O.I., Tyukavkina S.Y., Alekseeva L.P.


Background: Adhesion and ability to form a  biofilm are considered among the leading pathogenicity factors of Corynebacterium diphtheriaе, responsible for bacterial carriage. It is exactly bacterial carriage that ensures the circulation of diphtheria pathogen strains in the inter-epidemic periods. Aim: To assess and compare adhesivity of standard and biofilm cultures of toxigenic C. diphtheriae strains. Materials and methods: We studied standard and biofilm (120  and 720  hour) cultures of C.  diphtheriae strains. Their ability to form a  biofilm was tested according to P. Watnick (2000). Adhesivity was assessed in the pharyngeal epithelial carcinoma Hep-2 cell culture with various time exposures (2, 8, and 18  hours). The amounts of C. diphtheriae adhered to Нер-2 cells were measured by culturing the swabs in the 20% serum agar with subsequent calculation of mean numbers of colony-forming units (CFU) per 1  mL. Results: All standard and biofilm cultures of the studied toxigenic strains of C. diphtheriae had adhesive properties of various degrees. The highest adhesivity was found in a  circulating strain C.  diphtheriae gravis tox+ (from 0.26 ± 0.01 to 203.3 ± 3.3 CFU/mL), which differed from the same parameters in other strains studied (from 0.03 ± 0.003 to 0.20 ± 0.01  CFU/mL). The lowest adhesivity after a 2-hour exposure was found both in the standard and biofilm cultures of C.  diphtheriae gravis tox+ 6765, whereas after the exposure of 8 and 18  hours, the lowest adhesion properties were demonstrated by C.  diphtheriae gravis with a “silent” tox gene and C. diphtheriae mitis tox+ 269. All cultures of toxigenic C. diphtheriae strains showed a  statistically significant increase in their adhesivity (р ≤ 0.05) by 8 and 18  hour of cultivation. Conclusion: Circulating C.  diphtheriae gravis tox+ strain demonstrated the highest adhesivity among all toxigenic strains of the diphtheria pathogens studied. 

Almanac of Clinical Medicine. 2017;45(2):154-158
pages 154-158 views

The method for calculation of the energy density of culture media based on stoichiometrical patterns of the biological oxidative process

Khokhlova O.B., Kuznetsova E.D., Sapozhnikova N.G.


The proposed method for calculation of the energy value of culture media is based on stoichiometric properties of biological oxidative reactions in the cell and allows for assessment of the nutritional value of organic substrates with consideration of their elemental composition. Three organogen elements (carbon, hydrogen and oxygen) participate in the third stage of catabolism, which is the universal way of biological oxidation of organic nutritive substrate compounds. Their content in the composition of an organic compound (or food substrate) allows for calculation of the amount of energy converted into work during cellular metabolism. The idea to calculate the energy value of a food substrate is based on the principle of energetic conjugation, according to which the useful energy of food substrates within the cell is accumulated in the energy-rich adenosine triphosphate (ATP) bonds formed by biological oxidation of the substrate. Calculation of the energy values of organic substrate is traditionally based on the energy of the abiotic oxidation. The proportion of the useful energy converted into work is not considered in this case. The inherent problem of this approach is that the amount of ATP has been calculated only for several universal metabolites with known oxidative pathways, such as pyruvate and acetate. The proposed method is based on stoichiometric patterns and makes it possible to calculate the amount of ATP from the elemental composition of compounds and the mass fractions of carbon, hydrogen and oxygen. The results of calculation of biological oxidation energy obtained by this method coincide with the published data on biological oxidation metabolites in the citric acid cycle. The presented method, based on the composition of the compounds, allows for calculation of the energy value of any food substrate or culture medium containing a variety of organic compounds, including the case when their metabolic pathway of biological oxidation is unknown and the calculation of the bioenergetic value seems impossible. 

Almanac of Clinical Medicine. 2017;45(2):159-162
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Analysis of luminescence in turbid biological media

Guseva I.A., Rogatkin D.A., Buvalaya E.S.


Background: Quantitative luminescent analysis is widely used in biology, laboratory diagnostics and clinical medicine to study objects at various levels. However, the existing simplified algorithms for calculation of the luminophore concentration in diluted linear solutions cannot be applied to the turbid media with strong light scattering, which include the majority of living biological tissues. Today, the development of luminescence analysis in medicine goes towards the creation of non-destructive and non-invasive methods of in vivo monitoring. Therefore, the urgent question is about a formulation of the research purpose and the development of algorithms to compute the luminophore concentration based on the luminescence spectra recorded in the turbid media. Objective: To formulate and justify the tasks of elaboration of the algorithms to compute the luminophore concentration based on the luminescence spectra recorded under conditions of the optically turbid media. Materials and methods: We looked upon the physico-mathematical simulation of the process of formation of the induced fluorescence emission in the light-scattering medium based on the modified 2-flux Kubelka-Munch model. We conducted a series of laboratory experiments with macro-homogenous light-scattering model media to determine characteristics of the dependence of the fluorescence intensity detected from the surface of an optically turbid biological medium upon the factor of light scattering and the concentration of the fluorophore in the medium. Results: Both theoretical and experimental results demonstrate complex nonlinear dependence of the fluorescence intensity detected upon the optical properties and a  concentration of a  fluorophore in the turbid media. This dependence is very different from the known linear  C.  Parker's solution for transparent media, which makes it impossible to use it in the optically turbid media. Conclusion: Further studies searching a  closed-form analytical solution of the inverse optical problem for light-scattering and fluorescent media are necessary to calculate the luminophore concentration in a light-scattering media based on the recorded luminescence spectra.

Almanac of Clinical Medicine. 2017;45(2):163-169
pages 163-169 views

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