Using Machine Learning Algorithms to Determine the Post-COVID State of a Person by Their Rhythmogram.

This study introduces a novel method for detecting the post-COVID state using ECG data. By leveraging a convolutional neural network, we identify "cardiospikes" present in the ECG data of individuals who have experienced a COVID-19 infection. With a test sample, we achieve an 87 percent accuracy in detecting these cardiospikes. Importantly, our research demonstrates that these observed cardiospikes are not artifacts of hardware-software signal distortions, but rather possess an inherent nature, indicating their potential as markers for COVID-specific modes of heart rhythm regulation. Additionally, we conduct blood parameter measurements on recovered COVID-19 patients and construct corresponding profiles. These findings contribute to the field of remote screening using mobile devices and heart rate telemetry for diagnosing and monitoring COVID-19.

Fisheye piezo polymer detector for scanning optoacoustic angiography of experimental neoplasms.

A number of optoacoustic (or photoacoustic) microscopy and mesoscopy techniques have successfully been employed for non-invasive tumor angiography. However, accurate rendering of tortuous and multidirectional neoplastic vessels is commonly hindered by the limited aperture size, narrow bandwidth and insufficient angular coverage of commercially available ultrasound transducers. We exploited the excellent flexibility and elasticity of a piezo polymer (PVDF) material to devise a fisheye-shape ultrasound detector with a high numerical aperture of 0.9, wide 1-30 MHz detection bandwidth and 27 mm diameter aperture suitable for imaging tumors of various size. We show theoretically and experimentally that the wide detector's view-angle and bandwidth are paramount for achieving a detailed visualization of the intricate arbitrarily-oriented neovasculature in experimental tumors. The developed approach is shown to be well adapted to the tasks of experimental oncology thus allows to better exploit the angiographic potential of optoacoustics.

Noninvasive optoacoustic microangiography reveals dose and size dependency of radiation-induced deep tumor vasculature remodeling.

Tumor microvascular responses may provide a sensitive readout indicative of radiation therapy efficacy, its time course and dose dependencies. However, direct high-resolution observation and longitudinal monitoring of large-scale microvascular remodeling in deep tissues remained challenging with the conventional microscopy approaches. We report on a non-invasive longitudinal study of morphological and functional neovascular responses by means of scanning optoacoustic (ОА) microangiography. In vivo imaging of CT26 tumor response to a single irradiation at varying dose (6, 12, and 18 Gy) has been performed over ten days following treatment. Tumor oxygenation levels were further estimated using diffuse optical spectroscopy (DOS) with a contact fiber probe. OA revealed the formation of extended vascular structures on the whole tumor scale during its proliferation, whereas only short fragmented vascular regions were identified following irradiation. On the first day post treatment, a decrease in the density of small (capillary-sized) and medium-sized vessels was revealed, accompanied by an increase in their fragmentation. Larger vessels exhibited an increase in their density accompanied by a decline in the number of vascular segments. Short-lasting response has been observed after 6 and 12 Gy irradiations, whereas 18 Gy treatment resulted in prolonged responses, up to the tenth day after irradiation. DOS measurements further revealed a delayed increase of tumor oxygenation levels for 18 Gy irradiations, commencing on the sixth day post treatment. The ameliorated oxygenation is attributed to diminished oxygen consumption by inhibited tumor cells but not to the elevation of oxygen supply. This work is the first to demonstrate the differential (size-dependent) nature of vascular responses to radiation treatments at varying doses in vivo. The OA approach thus facilitates the study of radiation-induced vascular changes in an unperturbed in vivo environment while enabling deep tissue high-resolution observations at the whole tumor scale.

Raster-scan optoacoustic angiography of blood vessel development in colon cancer models.

Raster-scan optoacoustic angiography at 532 nm wavelength with 50 µm lateral resolution at 2 mm diagnostic depth was used for quantitative characterization of neoangiogenesis in colon cancer models. Two tumor models of human colon adenocarcinoma (HT-29) and murine colon carcinoma (CT26) different in their histology and vascularization were compared. Tumors of both origins showed an inhomogeneous distribution of areas with high and low vascularization. Rapidly growing CT26 tumor demonstrated a higher rate of vessel growth from the periphery to the center. Peculiarities of the vascularity of tumor models revealed by optoacoustic imaging were confirmed by fluorescent microscopy with FITC-dextran and morphological analysis. The obtained results may be important for the investigation of tumor development and for improvement of colon cancer treatment strategies.

Controlled release of goserelin from microporous polyglycolide and polylactide.

Two microporous biodegradable polyesters, i.e., PGA and PDLLA, were obtained by solid-state polymerization reaction from the sodium salts of the corresponding alpha-hydroxycarboxylic acids after washing out the by-product sodium chloride. The polymers were shaped by cold uniaxial pressing, by hot uniaxial pressing, and by extrusion at elevated temperature. Due to the special microporosity of the polymers, the introduction of drugs is possible at moderate temperature. The release kinetics of the model drug Phe and of the anti-tumor drug goserelin (an LH-RH agonist) from compacted polymer samples were fast (approx. 2 d). The release kinetics of goserelin were corrected for the decomposition of the drug. External coatings with PDLLA or PLLA obtained by immersion in polymer solution strongly slowed down the release kinetics in the case of the PDLLA coating, giving an almost linear release during 100 d. A coating with PLLA was unsuitable to slow down the release kinetics.