Changes in Anti-SARS-CoV-2 IgG Subclasses over Time and in Association with Disease Severity

IgG is the most prominent marker of post-COVID-19 immunity. Not only does this subtype mark the late stages of infection, but it also stays in the body for a timespan of at least 6 months. However, different IgG subclasses have different properties, and their roles in specific anti-COVID-19 responses have yet to be determined. We assessed the concentrations of IgG1, IgG2, IgG3, and IgG4 against different SARS-CoV-2 antigens (N protein, S protein RBD) using a specifically designed method and samples from 348 COVID-19 patients. We noted a statistically significant association between severity of COVID-19 infection and IgG concentrations (both total and subclasses). When assessing anti-N protein and anti-RBD IgG subclasses, we noted the importance of IgG3 as a subclass. Since it is often associated with early antiviral response, we presumed that the IgG3 subclass is the first high-affinity IgG antibody to be produced during COVID-19 infection.     

Estimating Low- and High-Cyclic Fatigue of Polyimide-CF-PTFE Composite through Variation of Mechanical Hysteresis Loops

The fatigue properties of neat polyimide and the “polyimide + 10 wt.% milled carbon fibers + 10 wt.% polytetrafluoroethylene” composite were investigated under various cyclic loading conditions. In contrast to most of the reported studies, constructing of hysteresis loops was performed through the strain assessment using the non-contact 2D Digital Image Correlation method. The accumulation of cyclic damage was analyzed by calculating parameters of mechanical hysteresis loops. They were: (i) the energy losses (hysteresis loop area), (ii) the dynamic modulus (proportional to the compliance/stiffness of the material) and (iii) the damping capacity (calculated through the dissipated and total mechanical energies). On average, the reduction in energy losses reached 10–18% at the onset of fracture, whereas the modulus variation did not exceed 2.5% of the nominal value. The energy losses decreased from 20 down to 18 J/m³ (10%) for the composite, whereas they reduced from 30 down to 25 J/m³ (17%) for neat PI in the low-cycle fatigue mode. For high-cycle fatigue, energy losses decreased from 10 to 9 J/m³ (10%) and from 17 to 14 J/m³ (18%) for neat PI and composite, respectively. For this reason, the changes of the energy losses due to hysteresis are of prospects for the characterization of both neat PI and the reinforced PI-based composites.     

Autoimmune Effect of Antibodies against the SARS-CoV-2 Nucleoprotein

COVID-19 caused by SARS-CoV-2 is continuing to spread around the world and drastically affect our daily life. New strains appear, and the severity of the course of the disease itself seems to be decreasing, but even people who have been ill on an outpatient basis suffer post-COVID consequences. Partly, it is associated with the autoimmune reactions, so debates about the development of new vaccines and the need for vaccination/revaccination continue. In this study we performed an analysis of the antibody response of patients with COVID-19 to linear and conformational epitopes of viral proteins using ELISA, chip array and western blot with analysis of correlations between antibody titer, disease severity, and complications. We have shown that the presence of IgG antibodies to the nucleoprotein can deteriorate the course of the disease, induce multiple direct COVID-19 symptoms, and contribute to long-term post-covid symptoms. We analyzed the cross reactivity of antibodies to SARS-CoV-2 with own human proteins and showed that antibodies to the nucleocapsid protein can bind to human proteins. In accordance with the possibility of HLA presentation, the main possible targets of the autoantibodies were identified. People with HLA alleles A01:01; A26:01; B39:01; B15:01 are most susceptible to the development of autoimmune processes after COVID-19.     

Videothoracosopy in diagnosis and surgical treatment of tuberculosis

From 1993 to May 2001, 795 psychiatric patients were treated including 563 with pleural effusion, 98 with multiple or solitary tuberculoma, 69 with tuberculous empyema, 14 with fibrotic-cavitary tuberculosis, 51 with disseminated tuberculosis. Mean age of the patients was 32 years. Survey of pleural cavity with pleural or lung biopsy was performed in 691 patients. In tuberculoma 14 lobectomies were performed, 23 patients underwent atypical lung resection without stapler (including with precise technique). Bilateral on-stage interventions were made in 32 patients. In empyema necrectomy and lung decortication were performed. 14 patients underwent videocavernoscopy with sequestrectomy and cavity drainage. In disseminated tuberculosis lung biopsy without staplers was usually performed. Aerohemostasis was achieved with plasma stream. One patient with empyema and one patient with pleural effusion died (lethality was 0.25%). Rate of postoperative complications was 7.5% in tuberculoma and 1.5% in disseminated tuberculosis. Conversion to thoracotomy was necessary in 3 (3%) patients with tuberculoma and 12 (17%) patients with empyema. Mean hospital stay was 4 days after diagnostic surgery and 7 days after lung resection. In pleural effusion diagnosis was verified in 98% cases, in disseminated tuberculosis--in 100%. Videothoracoscopy is the best diagnostic method for pleural effusion and disseminated forms of lung tuberculosis and operation of choice in tuberculoma and empyema. Videothoracoscopy in tuberculosis is highly effective and associates with low rate of postoperative complications and lethality.     

Natural orifice surgery with an endoluminal mobile robot

Natural orifice transgastric endoscopic surgery promises to eliminate skin incisions and reduce postoperative pain and discomfort. Such an approach provides a distinct benefit as compared with conventional laparoscopy, in which multiple entry incisions are required for tools and camera. Endoscopy currently is the only method for performing procedures through the gastrointestinal tract. However, this approach is limited by instrumentation and the need to pass the entire scope into the patient. In contrast, an untethered miniature robot inserted through the mouth would be able to enter the abdominal cavity through a gastrotomy for exploration of the entire peritoneal cavity. In this study, the authors developed an endoluminal robot capable of transgastric abdominal exploration under esophagogastroduodenoscopic (EGD) control. Under EGD control, a gastrotomy was created, and the miniature robot was deployed into the abdominal cavity under remote control. Ultimately, future procedures will include a family of robots working together inside the gastric and abdominal cavities after their insertion through the esophagus. Such technology will help to reduce patient trauma while providing surgical flexibility.     

Vascular density is highest in the proximal region of the mouse prostate

BACKGROUND: The proximal region of the prostatic ducts harbor the prostatic epithelial stem cells. As stem cell niches in other organs are highly vascularized, we determined if the proximal region is more highly vascularized than the remaining regions of the prostate. The effect of androgen on vascular density in the different prostatic regions was also examined. METHODS: Sections from prostates were immunostained with antibodies to CD31, and the vascular density in proximal, intermediate, and distal regions was calculated by image analysis software. Vascular density was compared in prostates from castrated mice that received daily inoculations of testosterone or vehicle alone for 3 days. To examine the role of angiogenic factors in the response to androgen, some animals were also treated with soluble VEGF receptor-2-Fc or Tie-2--Fc fusion proteins, which inhibit the activities of VEGF and angiopoietins, respectively. The endothelial proliferative response to androgen was determined by double staining sections with antibodies to CD31 and Ki-67. RESULTS: In prostates from intact mice, vascular density was highest in the proximal region and lowest in the distal region. Administration of testosterone to castrated mice increased vascular density to the greatest extent in the distal and intermediate regions. The increase in vascular density required VEGF and the angiopoietins. Endothelial cell proliferation was less sensitive to androgen in the proximal region than the remainder of the prostate. CONCLUSIONS: Vascular density is highest in the proximal region of the prostate, but the proximal vessels are less responsive to testosterone.