Sarcoplasmic reticulum function: comparison of atrial and ventricular myocardium

http://www.ester.ee/record=b1053410~S1*es

Veebipõhise tiimiõppe võtsid arstiüliõpilased entusiastlikult vastu

Eesti Arst 2021; 100(5):323 &nbsp

FANCMi immunohistokeemiline ekspressioon väheneb eesnäärmevähi stroomas sõltuvalt diferentseerumisastme rühmast

Eesti Arst 2021; 100(5):324 &nbsp

Mesothelioma: Overview of Technical, Immunochemical and Pathomorphological Diagnosing Aspects

For the clinicians with non-pathology background, first encountering the patients with pleural or peritoneal effusions, mesothelioma is only one statistically rare but clinically significant option of many differential diagnoses. This review aims to help the clinicians and broad life science audiences to understand step by step the possibilities and shortcomings of pathological diagnosing of mesothelioma, including the basic technical requirements. The first cytomorphology evaluation of pleural and peritoneal effusions in routinely stained smears enables in most cases only to identify cells suspicious for malignancy. The recent guidelines of epithelioid mesothelioma cytologic diagnosis and reporting emphasize immunochemistry (IC) in the cell blocks is mandatory whenever a diagnosis of malignancy is clinically entertained and/or cytologically suspected. The IC workup is challenging, since there is no fixed antibody panel, but multiple questions must be solved, such as 1) confirm the mesothelial or epithelial origin of isolated atypical cells and cell clusters; 2) delineate their benign or malignant nature; and 3) discriminate mesothelioma from other malignancies and metastatic disease. The rationale of the most widely clinically used IC markers is given and illustrated by the examples. The final confirmation of mesothelioma diagnosis and establishing its subtype and grade is possible only in the histological samples

Impact of sustainable tillage on biophysical properties of Planosol and on faba bean yield

Decreased tillage intensity can contribute to a reduced agro-technological footprint and stabilise the negative impact of climate change, especially in leguminous crop cultivation. For this reason, a long-term (since 1988) stationary field experiment has been performed on silty loam Planosol (in Lithuania). The main objective of this study was to establish the influence of sustainable tillage and no-tillage systems on soil aggregate stability to water, penetration resistance, enzymatic activity, abundance of earthworm and faba bean grain yield. Five different tillage systems were investigated: conventional deep and shallow mouldboard ploughing, deep chiselling, shallow disking and no-tillage. No-tillage in faba bean cultivation significantly increased soil structural stability by 40–97%, saccharase content by 0.7–2.0 times, urease activity by 3–4 times, the average quantity of earthworm by 55% and the biomass by 3.6 times. The impact of other ploughless tillage systems on soil properties was positive but not as significant. Faba bean grain yield was more influenced by growing seasons than by different tillage methods

Patohistoloogilise diagnostika digilahendused Eestis

Eesti Arst 2020; 99(5):320–32

The immediate effects of two manual therapy techniques on ankle musculoarticular stiffness and dorsiflexion range of motion in people with chronic ankle rigidity: A randomized clinical trial

OBJECTIVE: Ankle rigidity is a common musculoskeletal disorder affecting the talocrural joint, which can impair weight-bearing ankle dorsiflexion (WBADF) and daily-life in people with or without history of ankle injuries. Our objective was to compare the immediate effects of efficacy of Mulligan Mobilization with Movement (MWM) and Osteopathic Mobilization (OM) for improving ankle dorsiflexion range of motion (ROM) and musculoarticular stiffness (MAS) in people with chronic ankle dorsiflexion rigidity. DESIGN: A randomized clinical trial with two arms. METHODS: Patients were recruited by word of mouth and via social network as well as posters, and analyzed in the neuro musculoskeletal laboratory of the “Université Catholique de Louvain-la-Neuve”, Brussels, Belgium. PARTICIPANTS: 67 men (aged 18–40 years) presenting with potential chronic non-specific and unilateral ankle mobility deficit during WBDF were assessed for eligibility and finally 40 men were included and randomly allocated to single session of either MWM or OM. INTERVENTIONS: Two modalities of manual therapy indicated for hypothetic immediate effects in chronic ankle dorsiflexion stiffness, i.e. MWM and OM, were applied during a single session on included patients. MAIN OUTCOME MEASURES: Comprised blinding measures of MAS with a specific electromechanical device (namely: Lehmann’s device) producing passive oscillatory ankle joint dorsiflexion and with clinical measures of WBADF-ROM as well. RESULTS: A two-way ANOVA revealed a non-significant interaction between both techniques and time for all outcome measures. For measures of MAS: elastic-stiffness (p= 0.37), viscous-stiffness (p= 0.83), total-stiffness (p= 0.58). For WBADF-ROM: toe-wall distance (p= 0.58) and angular ROM (p= 0.68). Small effect sizes between groups were determined with Cohen’s d ranging from 0.05 to 0.29. One-way ANOVA demonstrated non-significant difference and small to moderate effects sizes (d= 0.003–0.58) on all outcome measures before and after interventions within both groups. A second two-way ANOVA analyzed the effect of each intervention on the sample categorized according to injury history status, and demonstrated a significant interaction between groups and time only for viscous stiffness (p= 0.04, d=-0.55). CONCLUSION: A single session of MWM and OM targeting the talocrural joint failed to immediately improve all measures in subjects with chronic ankle dorsiflexion stiffness. Despite this, there was an increase in viscous stiffness in people with history of ankle injury following both manual techniques, the value of which remains unclear even if it might help to prevent future abnormal ankle joint movements

History-Dependent Mechanical Properties of Permeabilized Rat Soleus Muscle Fibers

AbstractPermeabilized rat soleus muscle fibers were subjected to repeated triangular length changes (paired ramp stretches/releases, 0.03 l0,±0.1 l0 s−1 imposed under sarcomere length control) to investigate whether the rate of stiffness recovery after movement increased with the level of Ca2+ activation. Actively contracting fibers exhibited a characteristic tension response to stretch: tension rose sharply during the initial phase of the movement before dropping slightly to a plateau, which was maintained during the remainder of the stretch. When the fibers were stretched twice, the initial phase of the response was reduced by an amount that depended on both the level of Ca2+ activation and the elapsed time since the first movement. Detailed analysis revealed three new and important findings. 1) The rates of stiffness and tension recovery and 2) the relative height of the tension plateau each increased with the level of Ca2+ activation. 3) The tension plateau developed more quickly during the second stretch at high free Ca2+ concentrations than at low. These findings are consistent with a cross-bridge mechanism but suggest that the rate of the force-generating power-stroke increases with the intracellular Ca2+ concentration and cross-bridge strain

Low-force transitions in single titin molecules reflect a memory of contractile history

Titin is a giant elastomeric muscle protein that has been suggested to function as a sensor of sarcomeric stress and strain, but the mechanisms by which it does so are unresolved. To gain insight into its mechanosensory function we manipulated single titin molecules with high-resolution optical tweezers. Discrete, step-wise transitions, with rates faster than canonical Ig domain unfolding occurred during stretch at forces as low as 5 pN. Multiple mechanisms and molecular regions (PEVK, proximal tandem-Ig, N2A) are likely to be involved. The pattern of transitions is sensitive to the history of contractile events. Monte-Carlo simulations of our experimental results predicted that structural transitions begin before the complete extension of the PEVK domain. High-resolution atomic force microscopy (AFM) supported this prediction. Addition of glutamate-rich PEVK domain fragments competitively inhibited the viscoelastic response in both single titin molecules and muscle fibers, indicating that PEVK domain interactions contribute significantly to sarcomere mechanics. Thus, under non-equilibrium conditions across the physiological force range, titin extends by a complex pattern of history-dependent discrete conformational transitions, which, by dynamically exposing ligand-binding sites, could set the stage for the biochemical sensing of the mechanical status of the sarcomere

Conformation-regulated mechanosensory control via titin domains in cardiac muscle

The giant filamentous protein titin is ideally positioned in the muscle sarcomere to sense mechanical stimuli and transform them into biochemical signals, such as those triggering cardiac hypertrophy. In this review, we ponder the evidence for signaling hotspots along the titin filament involved in mechanosensory control mechanisms. On the way, we distinguish between stress and strain as triggers of mechanical signaling events at the cardiac sarcomere. Whereas the Z-disk and M-band regions of titin may be prominently involved in sensing mechanical stress, signaling hotspots within the elastic I-band titin segment may respond primarily to mechanical strain. Common to both stress and strain sensor elements is their regulation by conformational changes in protein domains