Cardiac troponins: current information on the main analytical characteristics of determination methods and new diagnostic possibilities

The methods used to diagnose cardiovascular diseases are constantly being improved, leading to an expanded perception of the diagnostic value of biomarkers and their new diagnostic possibilities. One striking example are the main biomarkers used to diagnose acute myocardial infarction: cardiac troponins. The first methods for determining cardiac troponins (proposed 30 years ago) were characterized by extremely low sensitivity. Therefore, they could only detect large acute myocardial infarctions. These methods were also characterized by low specificity, expressed as a high probability of cross-reactivity with skeletal troponin isoforms, which generated false-positive results in the presence of skeletal myopathies and skeletal muscle lesions. With the introduction of high-sensitivity cardiac troponins into clinical practice, the possibility of early diagnosis and exclusion of acute myocardial infarction by assessing troponin concentrations in the first few hours (from admission to the first hour, second hour, or third hour) has become more specific. Our knowledge about cardiac troponins has changed over the years and promising new medical uses have emerged. This paper reviews current data on the diagnostic value of cardiac troponins, the main methods used for their determination, and their analytical characteristics from historical and modern insights.

Interferon-gamma mediates skeletal muscle lesions through JAK/STAT pathway activation in inclusion body myositis

Dysimmune and Inflammatory Myopathies (DIMs) are acquired idiopathic myopathy associated with immune response dysregulation. Inclusion Body Myositis (IBM), the most common DIMs, is characterized by endomysial infiltrates of cytotoxic T lymphocytes CD8, muscle type II-interferon (IFNγ) signature, and by the lack of response to immunomodulatory therapies. We showed that IBM was pathologically characterized by the presence of chronic degenerative myopathic features including myofiber atrophy, fibrosis, adipose involution, and the altered functions of skeletal muscle stem cells. Here, we demonstrated that protracted systemic exposure to IFNγ delayed muscle regeneration and led to IBM-like muscular degenerative changes in mice. In vitro, IFNγ treatment inhibited the activation, proliferation, migration, differentiation, and fusion of myogenic progenitor cells and promoted their senescence through JAK-STAT-dependent activation. Finally, JAK-STAT inhibitor, ruxolitinib abrogated the deleterious effects of IFNγ on muscle regeneration, suggesting that the JAK-STAT pathway could represent a new therapeutic target for IBM.

Pain-Induced Impact on Movement: Motor Coordination Variability and Accuracy-Based Skill

Studies on pain are generally conducted for two purposes: first, to study patients with pain who have physical changes due to nerve and muscle lesions, and second, to regain the appropriate kinematic post-pain pattern. The present study aimed to investigate the effect of pain on the coordination variability pattern and throw accuracy. Participants included 30 people with a mean age of 18-25 years who volunteered to participate in the study. Individuals were randomly divided into three groups of local pain, remote pain, and control group. Without pain, participants practiced and acquired skills in 10 blocks of 15 trials. In the retention and transition phase, which were associated with pain, in their respective groups, included 1 hour, 24- hour, and 1- week acquisition; they were re-tested twice in a 15-block trial, which was once with and without pain. The results revealed that pain did not affect the throwing accuracy (p = 0.469). Besides, in the phase of decreasing acceleration in throwing, movement variability pattern in the pain-related groups in the shoulder and elbow joints (p = 0.000), elbow and wrist (p = 0.000), were more than the painless groups. Based on the results, it can be said that the increase in variability in pain-related groups is due to the different strategies and patterns that individuals use to avoid pain. Also, despite the pain, the nervous system attempts to increase the variability find the least painful pattern of movement and reduces this variability over time and using a repetitive pattern.

Study of stimulation impedance myography contractions predictive indicators in occlusion lesions of lower extremities vessels

As a predictive indicator of tissue viability in multiple muscle lesions used the percentage of high-, medium- and low amplitude contracting reactions (СR) or their absence, recorded by stimulation impedance myography contraction (SIMC). After examining the boundaries of the scattering of amp-omic muscle curves of the limbs, the patients determined the distribution of maximum contractile reactions (MSRs) by the angles of tilt curves in the coordinate plane. After examining the boundaries of the scattering of amp-omic muscle curves of the limbs, the patients determined the distribution of maximum contractile reactions (MCRs) by the angles of tilt curves in the coordinate plane. Average sectoral values of MSR were distributed in reverse dependence of amplitudes on the amount of stimulus in the form of hyperbole containing high-, medium-, and low-amplitude MSD, the percentage of which were based on the profiles of histograms of patients with known clinical diagnoses. Comparison of histogram profiles of different stages of chronic ischemic syndrome among themselves showed their high distinguishing ability and correlation of histograms with diagnoses.

Pain-Induced Impact on Movement: Motor Coordination Variability and Accuracy-Based Skill

Studies on pain are generally conducted for two purposes: first, to study patients with pain who have physical changes due to nerve and muscle lesions, and second, to regain the appropriate kinematic post-pain pattern. The present study aimed to investigate the effect of pain on the coordination variability pattern and throw accuracy. Participants included 30 people with a mean age of 18-25 years who volunteered to participate in the study. Individuals were randomly divided into three groups of local pain, remote pain, and control group. Without pain, participants practiced and acquired skills in 10 blocks of 15 trials. In the retention and transition phase, which were associated with pain, in their respective groups, included 1 hour, 24- hour, and 1- week acquisition; they were re-tested twice in a 15-block trial, which was once with and without pain. The results revealed that pain did not affect the throwing accuracy (p = 0.469). Besides, in the phase of decreasing acceleration in throwing, movement variability pattern in the pain-related groups in the shoulder and elbow joints (p = 0.000), elbow and wrist (p = 0.000), were more than the painless groups. Based on the results, it can be said that the increase in variability in pain-related groups is due to the different strategies and patterns that individuals use to avoid pain. Also, despite the pain, the nervous system attempts to increase the variability find the least painful pattern of movement and reduces this variability over time and using a repetitive pattern.

Neurological diseases in the context of the COVID-19 pandemic (review of the literature)

Currently, there is a world-wide pandemic of a new viral infection — COVID-19. The Russian Federation ranks third in the world in the number of detected cases. In the context of the current pandemic, neurological departments are reassigned to infectious diseases departments, the routing of patients is changing, and patients with neurological symptoms are less likely to seek medical help because of the fear of SARS-CoV-2 infection. At the same time, early diagnosis of neurological diseases, including acute cerebrovascular accident, becomes even more complicated, and treatment standards are not always fully applicable. This situation further emphasizes the medical and social significance of neurological diseases. There is evidence that acute cardiovascular diseases can develop as a complication of SARS-CoV-2 infection and vice versa — preexisting cardiovascular diseases aggravate the course of COVID-19. The direct and indirect effects of the virus on the central and peripheral nervous system are discussed. Cases of necrotizing encephalopathy, Guillain-Barr syndrome, a clinical picture of skeletal muscle lesions associated with the COVID-19 infection are described. This article provides an overview of the available world literature on this topic.