Changes in the spectral characteristics of biological tissues depending on temperature

This work was aimed at determining the optical characteristics of biological samples at different temperatures. The work investigated the change in the intensity and shape of the absorption spectra of various biological tissues in vitro, depending on the sample temperature

Phototoxicity and luminescence of the upconversion nanoparticles embedded in the cells

The present work demonstrates the visualization of the intracellular distribution of upconversion nanoparticles (UCNPs) by microscopy with excitation in the NIR spectral range and detection of upconversion luminescence in the VIS range. The cell viability is scored for cytotoxic effects of UCNPs at dark and light exposed conditions. Non-functionalized UCNPs incubated with the cells are found to be endocytosed by cells. The obtained results confirm a high sensitivity of the luminescent UCNPs to the concentration variations within cells. UCNPs are promising alternatives to traditional fluorescent labels for cell imaging and possess prominent potentials in biological and clinical applications

Effect of luminescence transport through adipose tissue on measurement of tissue temperature by using ZnCdS nanothermometers

The spectra of luminescence of ZnCdS nanoparticles (ZnCdS NPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the signal of luminescence of ZnCdS NPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. It is shown that the presence of a phase transition in adipose tissue upon its heating (polymorphic transformations of lipids) leads to a nonmonotonic temperature dependence of the intensity of luminescence for the nanoparticles introduced into adipose tissue. This is due to a change in the light scattering by the tissue. The light scattering of adipose tissue greatly distorts the results of temperature measurements. The application of these nanoparticles is possible for temperature measurements in very thin or weakly scattering samples

Temperature sensing of adipose tissue heating with the luminescent upconversion nanoparticles as nanothermometer: In vitro study

The luminescence spectra of upconversion nanoparticles (UCNPs) imbedded in fat tissue were measured in a wide temperature range, from room to human body and further to hyperthermic temperatures. The two types of synthesized UCNP [NaYF4:Yb3+, Er3+] specimens, namely, powdered as-is and embedded into polymer film, were used. The results show that the luminescence of UCNPs placed under the adipose tissue layer is reasonably good sensitive to temperature change and reflects phase transitions of lipids in tissue cells. The most likely, multiple phase transitions are associated with the different components of fat cells such as phospholipids of cell membrane and lipids of fat droplets. In the course of fat cell heating, lipids of fat droplet first transit from a crystalline form to a liquid crystal form and then to a liquid form, which is characterized by much less scattering. The phase transitions of lipids were observed as the changes of the slope of the temperature dependence of UCNP luminescence intensity. The obtained results confirm a high sensitivity of the luminescent UCNPs to the temperature variations within tissues and show a strong potential for providing a controllable tissue thermolysis

The study of spectral changes in THz range in normal and pathological skin in vivo depending on the dehydration methods used

The terahertz (THz) attenuated total reflectance (ATR) imaging of normal and pathological skin under the action of various dehydration agents was carried out in vivo. Studies were conducted on animal models (the mouse), patients with diabetes, and healthy volunteers. For measurements, each animal was leaned against the ATR prism of the skin surface, and several locations in the skin of each animal were analyzed. Places on the skin for analysis were chosen so that the intensity spectra of the THz signal were practically the same for selected points. THz spectra measurements were carried out every 10 minutes within 45 minutes interval under the action of a dehydration agent. 40% glucose was shown to provide the most effective improving tissue optical clearing effect in the THz range

Delivery and reveal of localization of upconversion luminescent microparticles and quantum dots in the skin in vivo by fractional laser microablation, multimodal imaging, and optical clearing

Delivery and spatial localization of upconversion luminescent microparticles [Y 2 O 3 ;Yb, Er] (mean size ~1.6 μm) and quantum dots (QDs) (CuInS 2 ZnS nanoparticles coated with polyethylene glycol-based amphiphilic polymer, mean size ~20 nm) inside rat skin was studied in vivo using a multimodal optical imaging approach. The particles were embedded into the skin dermis to the depth from 300 to 500 μm through microchannels performed by fractional laser microablation. Low-frequency ultrasound was applied to enhance penetration of the particles into the skin. Visualization of the particles was revealed using a combination of luminescent spectroscopy, optical coherence tomography, confocal microscopy, and histochemical analysis. Optical clearing was used to enhance the image contrast of the luminescent signal from the particles. It was demonstrated that the penetration depth of particles depends on their size, resulting in a different detection time interval (days) of the luminescent signal from microparticles and QDs inside the rat skin in vivo. We show that luminescent signal from the upconversion microparticles and QDs was detected after the particle delivery into the rat skin in vivo during eighth and fourth days, respectively. We hypothesize that the upconversion microparticles have created a long-time depot localized in the laser-created channels, as the QDs spread over the surrounding tissues

In vivo optical monitoring of transcutaneous delivery of calcium carbonate microcontainers

We have developed a method for delivery of biocompatible CaCO3 microcontainers (4.0 ± 0.8 µm) containing Fe3O4 nanoparticles (14 ± 5 nm) into skin in vivo using fractional laser microablation (FLMA) provided by a pulsed Er:YAG laser system. Six laboratory rats have been used for the microcontainer delivery and weekly monitoring implemented using an optical coherence tomography and a standard histological analysis. The use of FLMA allowed for delivery of the microcontainers to the depth about 300 μm and creation of a depot in dermis. On the seventh day we have observed the dissolving of the microcontainers and the release of nanoparticles into dermis

Two years of experience in hospital surveillance for the severe influenza like illnesses in St. Petersburg: etiology, clinical characterization of diseases, antigenic and genetic properties of isolated influenza viruses

In this paper, we analyze the etiology of the diseases occurring during two consecutive influenza epidemic seasons in St. Petersburg, Russian Federation. The analysis is based on the results of the PCR diagnostics of the clinical samples collected from patients hospitalized in three St. Petersburg hospitals with influenza like illnesses (ILI). It was shown that the influenza virus A(H1N1)pdm09 was the dominant causative agent during the 2012-2013 epidemic season while, in the 2013-2014 season, A(H3N2) virus was predominant among adults and children. The influenza B virus activity was high in the 2012-2013 season and low in the 2013-2014 season. During both seasons, the main causative agent for the hospitalization of young children was respiratory syncytial virus (RSV), followed by rhinovirus and influenza virus. The rate of involvement of parainfluenza, adenovirus, metapneumovirus and coronavirus was low and was negligible for bocavirus. Children 0-2 and 3-6 years old formed the group of patients that was affected by acute respiratory infection agents the most. Children younger than 3 months old were the major group of the intensive care unit (ICUs) patients and only 27.5% of them were adults. RSV and rhinovirus were the leading cause of ILI among the children admitted to ICU. Among the adult patients admitted to the ICU, only influenza A(H1N1)pdm09, A(H3N2) and B viruses were detected during both influenza seasons.According to the results of the antigenic and genetic analysis, most influenza A(H1N1)pdm09 and A(H3N2) viruses circulating in St. Petersburg matched the vaccine strains recommended by the WHO for vaccine composition in the 2012-2013 and 2013-2014 seasons.In this paper, we analyze the etiology of the diseases occurring during two consecutive influenza epidemic seasons in St. Petersburg, Russian Federation. The analysis is based on the results of the PCR diagnostics of the clinical samples collected from patients hospitalized in three St. Petersburg hospitals with influenza like illnesses (ILI). It was shown that the influenza virus A(H1N1)pdm09 was the dominant causative agent during the 2012-2013 epidemic season while, in the 2013-2014 season, A(H3N2) virus was predominant among adults and children. The influenza B virus activity was high in the 2012-2013 season and low in the 2013-2014 season. During both seasons, the main causative agent for the hospitalization of young children was respiratory syncytial virus (RSV), followed by rhinovirus and influenza virus. The rate of involvement of parainfluenza, adenovirus, metapneumovirus and coronavirus was low and was negligible for bocavirus. Children 0-2 and 3-6 years old formed the group of patients that was affected by acute respiratory infection agents the most. Children younger than 3 months old were the major group of the intensive care unit (ICUs) patients and only 27.5% of them were adults. RSV and rhinovirus were the leading cause of ILI among the children admitted to ICU. Among the adult patients admitted to the ICU, only influenza A(H1N1)pdm09, A(H3N2) and B viruses were detected during both influenza seasons. According to the results of the antigenic and genetic analysis, most influenza A(H1N1)pdm09 and A(H3N2) viruses circulating in St. Petersburg matched the vaccine strains recommended by the WHO for vaccine composition in the 2012-2013 and 2013-2014 seasons

Особенности этиологической структуры ОРВИ в отдельных возрастных и профессиональных группах населения Санкт-Петербурга в эпидемический сезон 2013-2014 гг .

The objective. To study etiological structure of acute respiratory viral diseases in the hospitalized patients of different age groups and to reveal their peculiarities in children and adults, as well as in adults of draft age (18–26 years) among civilians and military recruits.Materials and methods. 2202 in patients with acute respiratory diseases of moderate and severe degree, including 1123 patients (51.0%) aged up to 18 years and 1079 patients (49,0%) aged 18 years and above, were examined during the epidemic season since September 2013 till July 2014. RNA or DNA of influenza A(H1N1)pdm09 and A(H3N2), influenza B, types 1–4parainfluenza, adenoviruses, respiratory syncytial virus, rino-, metapneumo-, corona-, entero- and boca- viruses were determinedin nasopharyngeal swabs, sputum and brohchoalveolar lavage by real time PCR method. Significance of differences (p<0,05) in cases incidence of compared independent groups were assessed by the Pearson,s χ2 (chi-squared) test.Results. Genetic material of viruses causing ARD was revealed in 1343 cases (61,0%). Influenza viruses A and B (30,3%), RS viruses (23,6%), rinoviruses (22,8%) and adenoviruses (12,5%) prevail among ARD viral pathogens. The parainfluenza virus infection was laboratory confirmed in 8,7%, coronavirus – in 4,4%, bocavirus – in 1,2%, enterovirus – in 0,7% of cases. Assessment of age-related features of ARD etiologic structure showed that RS virus (37,6%, p<0,05) and parainfluenza virus (11,3%, p<0,05) infections were registered significantly often among children. Influenza viruses (46,4%, p<0,05), adenovirus (26,3%, p<0,05) and rinovirus (25,7%, p<0,05) were verified significantly often among adults. Etiologic ARD structure of military personnel 18–26 years old was characterized by significant prevalence of adenovirus infection (53,9%, p<0,05).Conclusion. The study has shown that acute respiratory diseases caused by RS and parainfluenza viruses predominated among children, by influenza viruses – among adults (civilians) and by adenovirus – among military personnel.Цель. Исследовать этиологическую структуру острых респираторных вирусных заболеваний у госпитализированных больных в разных возрастных и профессиональных группах и выявить ее особенности у детей и взрослых, а также у взрослых призывного возраста (18– 26 лет) из числа гражданских лиц и военнослужащих.Материалы и методы. В эпидемический сезон с сентября 2013 г. по июль 2014 г. обследовано 2202 стационарных больных острыми респираторными заболеваниями средней и тяжелой степенями тяжести, в том числе в возрасте до 18 лет – 1123 пациента (51,0%), 18 лет и старше – 1079 пациентов (49,0%). РНК или ДНК вирусов гриппа А(H1N1)pdm09 и А(H3N2), гриппа В, парагриппа 1–4 типов, аденовирусов, респираторно-синцитиального вируса, рино-, метапневмо-, корона-, бока- и энтеровирусов определяли в носоглоточных смывах, мокроте и бронхоальвеолярном лаваже методом ПЦР. Достоверность различия (p<0,05) частоты встречаемости случаев в сравниваемых независимых группах оценивали по критерию χ2 (хи-квадрат) Пирсена.Результаты. При обследовании больных генетический материал вирусов, вызывающих ОРЗ, выявлен в 1343 случаях (61,0%). Среди респираторных вирусов в качестве возбудителей ОРЗ доминируют вирусы гриппа А и В (30,3%), РС-вирусы (23,6%), риновирусы (22,8%) и аденовирусы (12,5%). Парагриппозная инфекция установлена в 8,7%, коронавирусная – в 4,4%, бокавирусная – в 1,2%, энтеровирусная – в 0,7% случаев. При оценке возрастных особенностей этиологической структуры ОРЗ выявлено, что среди детей достоверно чаще регистрировали РС-вирусную (37,6%, p<0,05) и парагриппозную (11,3%, p<0,05) инфекции. У взрослых достоверно чаще верифицировали грипп (46,4%, p<0,05), аденовирусную (26,3%, p<0,05) и риновирусную (25,7%, p<0,05) инфекции. Особенностью этиологической структуры ОРЗ у военнослужащих в возрасте 18–26 лет является достоверное преобладание аденовирусной инфекции (53,9%, p<0,05).Заключение. Исследование показало, что в структуре ОРЗ среди детей достоверно чаще регистрируют РС-вирусные заболевания и парагрипп, среди взрослых –грипп (у гражданских лиц) и аденовирусную инфекцию (у военнослужащих)