The Role of Oxygen in the Priming of Neutrophils on Exposure to a Weak Magnetic Field

A preliminary mild partial degassing of a neutrophil suspension at an atmospheric gas pressure of 640 mm Hg was accompanied by a decrease in oxygen to 412 ng-atom O/mL and was shown to cause a significant (fourfold) decrease in neutrophil priming index on exposure to combined weak magnetic fields (a static magnetic field of 42 μT and a low-frequency collinear alternating magnetic field of 860 nT; 1, 4.4, and 16.5 Hz) but did not affect the cell potential to generate a respiratory burst in response to an activator (the peptide N-formyl–Met–Leu–Phe) in the control. A partial replacement of the air mixture with carbogen, xenon, or sulfur hexafluoride reduced the intensity of luminol-dependent chemiluminescence of the samples.     

Effect of weak and ultraweak static magnetic fields on the intensity of fission of the planarian Dugesia tigrina

It has been shown that, in the range of 03000 nT, a biological system differently responds to the treatment with a weak static magnetic field. Thus, at a practically complete compensation of the field (induction 5 nT), the intensity of fission of planarian does not differ from control values. As the field intensity is successively increased to 300 nT, a marked and statistically significant stimulating effect is observed (SC 1.51.8), which disappears in the intensity range of 400 and 600 nT. At intensities from 800 to 1500 nT, the stimulating effect manifests itself again. Further increase of field intensity to 3000 nT leads to the disappearance of the effect.     

Effect of weak and superweak combined permanent and low-frequency alternating magnetic fields and low-intensity millimeter waves on regeneration of planaria Dugesia tigrina

It has been shown that exposure to weak combined collinear magnetic fields (permanent component 42 mT; amplitude of alternating component 40 nT, frequency 3.7 Hz) or millimeter waves with a frequency of 36 GHz and power density of 100 mT/cm2 substantially stimulates the growth of the regeneration blastema in the tail fragment of planaria when the exposure to fields precedes the cutting of the planaria body. This effect is more clearly pronounced during the treatment of planaria with magnetic field. If the treatment with weak physical factors is carried out after the cutting of planaria, the effect of the field is two times less pronounced (exposure to magnetic waves) or is not evident at all (exposure to electromagnetic radiation).     

Study of the quaternary structure of rat 1-Cys peroxiredoxin

Peroxiredoxins (Prx) are a family of antioxidant proteins with peroxidase activity. The ability of 1-Cys Prx to self-associate was studied with the use of native PAGE and Western blotting. Two protein bands corresponding to monomeric and dimeric forms were detected in the preparation of the recombinant 1-Cys Prx subjected to native PAGE, with dimers being more abundant. The third band corresponding to the oligomeric form was detected after incubation of the recombinant 1-Cys Prx with DTT, although monomers and dimers were also observed. These results indicate that monomeric, dimeric, and oligomeric states of the protein are likely to be interchangeable. Native PAGE in combination with Western blot analysis revealed that self-association of 1-Cys Prx also occurred at physiologically relevant concentrations in vivo. The native 1-Cys Prx existed in the monomeric and dimeric forms in rat olfactory epithelium, with monomers being more common. The structural sensitivity of the recombinant 1-Cys Prx to imidazole was shown.     

A novel 45 kDa secretory protein from rat olfactory epithelium: primary structure and localisation.

cDNA clones encoding the 45 kDa protein were isolated from a rat olfactory epithelium cDNA library and their inserts were sequenced. The reconstructed protein sequence comprises 400 amino acids with a calculated molecular mass of 46,026 Da. A homology was revealed between the amino acid sequence of the 45 kDa protein and the proteins involved in the transfer of hydrophobic ligands. Using in situ hybridisation, the 45 kDa protein mRNA expression was detected in the layer of supportive cells of olfactory epithelium, apical region of trachea, surface layer of the ciliated bronchial epithelium in lung and in skin epidermis.     

Repercussions of the COVID-19 pandemic on athletes: a cross-sectional study

The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes’ characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports.     

Seasonal changes in proteolytic activity of calpains in striated muscles of long-tailed ground squirrel <Emphasis Type="Italic">Spermophilus undulatus</Emphasis>

Seasonal changes in proteolytic activity and content of calpains in striated muscles of the longtailed ground squirrel Spermophilus undulatus were studied by casein zymography and Western blotting analysis. The results testify to hyperactivation of calpain proteases in the skeletal muscles of awakened animals during the “winter” activity. The observed changes are discussed in the context of adaptation of skeletal muscles of long-tailed ground squirrels to hibernation.     

Three-dimensional ultrastructural and immunohistochemical study of immature neurons in the subgranular zone of the rat dentate gyrus

The present study is devoted to three-dimensional ultrastructural organization of mitotically dividing immature neurons in dentate gyrus using biophysical approaches. In adult vertebrate brain, cell proliferation persists throughout life mainly in dentate gyrus of the hippocampus (DG) and olfactory bulb. Neurogenesis has been demonstrated using tagged thymidine analogues incorporated into the S phase of the cell cycle, but these may also detect repaired DNA in postmitotic neurons. Recent retroviral labelling has shown that neuronal progenitors/neuroblasts divide and produce functional neurons. Providing ultrastructural evidence of mitotically active cells has proven problematical, not only because of technical issues of identifying dividing cells at electron microscope level, but also because it is difficult to demonstrate unequivocally that neurons identified in the electron microscope are really post mitotic. However by characterising post mitotic cells labelled with BrdU and doublecortin and comparing these with post mitotic cells reconstructed in 3-dimensions from ultrathin serial sections, we have been able to illustrate individual mitotic elements and phases of cells within the GC layer of adult rat dentate gyrus. Here we show dividing cells in metaphase within clusters of immature GCs in subgranular zone (SGZ). These reconstructions provide ultrastructural confirmation that cells expressing doublecortin (DCX), a microtubule-associated protein expressed in migrating neurons, localize as clusters in the subgranular zone (SGZ) of dentate gyrus (DG) in the hippocampus during all animal life. Such DG cells with clear synaptic specializations, somatic spines and basal dendrites are exclusive to immature GC that appear to re-enter the cell cycle, suggesting the possibility that newly generated neurons within the DG might arise not only from precursors, but also from clusters of immature GC.     

马鹿茸血酶解肽体内免疫功能及抗氧化功能关系的研究

本文分别选用由木瓜蛋白酶水解天山马鹿茸血获得的肽Ⅰ、肽Ⅱ以及原血为受试样品,研究天山马鹿茸血及其酶解肽对小鼠免疫功能和抗氧化功能的影响,其中肽Ⅰ、肽ⅡDH分别为18．1％、12．2％时,清除OH&#183;能力最强,清除率为50．8％。分别测定了脏器指数,脾细胞增殖实验,血清中溶血素和抗体生成细胞的含量以及小鼠血清总抗氧化能力、SOD活力和MDA含量。结果表明：与对照组相比较,肽Ⅱ组能极显著提高小鼠体液和细胞免疫功能,加强小鼠的抗氧化功能（P〈0．01或P〈0．05）。此外,具有较强抗氧化活性的肽显示出了很强的免疫活性（P〈0．05）。