SURGICAL TREATMENT OF HYPERTENSION-DUCTAL TYPE OF CHRONIC PANCREATITIS, IN COMBINATION WITH BILIARY OBSTRUCTION SYNDROME

Background. The frequency of chronic pancreatitis and its complications is steadily increasing, which makes the problem of treating this pathology one of the most urgent and significant. Objective. Improvement of the results of surgical treatment of patients with hypertension-ductal type of chronic pancreatitis with extended stricture of the intrapancreatic part of the common bile duct. Material and methods. During the period 2006–2021, 328 operations were performed in the Grodno University Clinic due to chronic pancreatitis with pathology of the ductal system in combination with pancreatic cysts. The total number of complications was 5,1%. 18 patients with chronic recurrent pancreatitis, ductal hypertension in combination with a cyst of the head pancreas, also with extended stricture of the terminal part common bile duct and mechanical jaundice were operated on according to the methods developed in the clinic: 12 patients underwent choledochopancreatoejunostomy, 5 patients underwent choledochocystopancreatoejunostomy, choledochocystoduodenostomy was performed in 1 case. Results. The developed methods make it possible to perform adequate internal drainage of the ductal system of the pancreas and bile ducts, as well as cystic formations. Conclusions. The application of the developed methods improves the results of surgical treatment complicated chronic pancreatitis.

Nematode CDC-37 and DNJ-13 form complexes and can interact with HSP-90

The molecular chaperones Hsc70 and Hsp90 are required for proteostasis control and specific folding of client proteins in eukaryotic and prokaryotic organisms. Especially in eukaryotes these ATP-driven molecular chaperones are interacting with cofactors that specify the client spectrum and coordinate the ATPase cycles. Here we find that a Hsc70-cofactor of the Hsp40 family from nematodes, DNJ-13, directly interacts with the kinase-specific Hsp90-cofactor CDC-37. The interaction is specific for DNJ-13, while DNJ-12 another DnaJ-like protein of C. elegans, does not bind to CDC-37 in a similar manner. Analytical ultracentrifugation is employed to show that one CDC-37 molecule binds to a dimeric DNJ-13 protein with low micromolar affinity. We perform cross-linking studies with mass spectrometry to identify the interaction site and obtain specific cross-links connecting the N-terminal J-domain of DNJ-13 with the N-terminal domain of CDC-37. Further AUC experiments reveal that both, the N-terminal part of CDC-37 and the C-terminal domain of CDC-37, are required for efficient interaction. Furthermore, the presence of DNJ-13 strengthens the complex formation between CDC-37 and HSP-90 and modulates the nucleotide-dependent effects. These findings on the interaction between Hsp40 proteins and Hsp90-cofactors provide evidence for a more intricate interaction between the two chaperone systems during client processing.

Hereditary Xerocytosis: Differential Behavior of PIEZO1 Mutations in the N-Terminal Extracellular Domain Between Red Blood Cells and HEK Cells

Hereditary Xerocytosis, a rare hemolytic anemia, is due to gain of function mutations in PIEZO1, a non-selective cation channel activated by mechanical stress. How these PIEZO1 mutations impair channel function and alter red blood cell (RBC) physiology, is not completely understood. Here, we report the characterization of mutations in the N-terminal part of the protein (V598M, F681S and the double mutation G782S/R808Q), a part of the channel that was subject of many investigations to decipher its role in channel gating. Our data show that the electrophysiological features of these PIEZO1 mutants expressed in HEK293T cells are different from previously characterized PIEZO1 mutations that are located in the pore or at the C-terminal extracellular domain of the protein. Although RBC with PIEZO1 mutations showed a dehydrated phenotype, the activity of V598M, F681S or R808Q in response to stretch was not significantly different from the WT channels. In contrast, the G782S mutant showed larger currents compared to the WT PIEZO1. Interestingly, basal activity of all the mutated channels was not significantly altered at the opposite of what was expected according to the decreased water and cation contents of resting RBC. In addition, the features of mutant PIEZO1 expressed in HEK293 cells do not always correlate with the observation in RBC where PIEZO1 mutations induced a cation leak associated with an increased conductance. Our work emphasizes the role of the membrane environment in PIEZO1 activity and the need to characterize RBC permeability to assess pathogenicity to PIEZO1 mutants associated with erythrocyte diseases.

Effectiveness and prognostic value of intravscular imaging in patients with left main coronary artery stenosis and heart failure

Aims A comparative analysis and evaluate the effectiveness and prognostic value of optical coherence tomography (OCT) and fractional flow reserve (FFR) guiding measurement in patients with stenosis of the terminal part of the left main coronary artery (LMCA). Methods 222 patients were selected in the study. Inclusion criteria: true bifurcation stenosis of the LMCA according to quantitative coronary angiography (QCA) and classification by A. Medina. Criteria for determining the hemodynamic significance of stenosis: according OCT - minimal lumen area (MLA) in the terminal part of LMCA <6 mm2; according FFR guiding – <0.8 (in LCx or LAD or both). Patients, who have not been diagnosed hemodynamically significant stenosis, were further subjected to the dynamic observation. All received optimal medical therapy. The study continued to participate patients whose compliance to receive drugs was not lower than 80%. Primary endpoints: frequency of MACE (death, myocardial infarction, revascularizations). The follow-up were 12, 24, 36 months. Results The OCT was performed in 110 patients and FFR guiding measurement – in 112 patients. According to the OCT, were hemodynamically significant stenoses are determined in 36 (32.7%) patients and after FFR-guiding measurement – in 32 (28.6%) of patients (χ2=2.184 p>0.05). Patients without hemodynamically significant stenoses distributed into 2 groups: group 1 (n=74) – according to the OCT and group 2 (n=80) – according to the FFR. The long-term results were monitored in all patients. The frequency of myocardial infarction in group 1 were 1.4% and in group 2 – 7.5% (p<0.05).The frequency of revascularization in group 1 were 5.4% and in group 2 – 15% (p<0.05). The total frequency of major cardiac events were 6.75% in group I and 22.5% in group II (χ2=6.435; p<0.001). The survival without major cardiac events (Kaplan-Maier analysis) were significantly differ between the groups, of 93.25% in group 1 and 77.5% – in group 2 (χ2=7.162 p<0.001). Conclusions The effectiveness of the OCT imaging and the FFR-guiding measurement in determining the hemodynamic significance of the bifurcation stenosis of the LMCA, not different. However, in the long term period, patients with insignificant stenosis identified by the FFR, have a worse prognosis and are distinguished by a major cardiac events, compared with the OCT, which does not allow us to recommend the FFR method as the main one for determining the hemodynamic significance of LMCA. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russian academic excellence project 5-100

Identifying key determinants and dynamics of SARS-CoV-2/ACE2 tight interaction

SARS-CoV-2 virus, the causative agent of Covid-19, has fired up a global pandemic. The virus interacts with the human receptor angiotensin-converting enzyme 2 (ACE2) for an invasion via receptor binding domain (RBD) on its spike protein. To provide a deeper understanding of this interaction, we performed microsecond simulations of the RBD-ACE2 complex for SARS-CoV-2 and compared it with the closely related SARS-CoV discovered in 2003. We show residues in the RBD of SARS-CoV-2 that were mutated from SARS-CoV, collectively help make the RBD anchor much stronger to the N-terminal part of ACE2 than the corresponding residues on RBD of SARS-CoV. This would result in a reduced dissociation rate of SARS-CoV-2 from human receptor protein compared to SARS-CoV. The phenomenon was consistently observed in simulations beyond 500 ns and was reproducible across different force fields. Altogether, our study adds more insight into the critical dynamics of the key residues at the virus spike and human receptor binding interface and potentially aids the development of diagnostics and therapeutics to combat the pandemic efficiently.

An unusual combined chromosomal rearrangement in a newborn with multiple congenital malformations due to a balanced parental translocation

Представлен случай сочетанной хромосомной патологии - частичной трисомии по субтеломерному участку длинного плеча хромосомы 5 и по протяжённому участку хромосомы 9 у новорождённого ребёнка с множественными врождёнными пороками развития и кариотипом 47,XY,t(5;9)(q35;q31),+der(9)t(5;9)(q35;q31)pat. Причиной хромосомного дисбаланса явилось редкое нарушение формирования гамет в мейозе II отца, являющегося носителем аутосомной реципрокной транслокации t(5;9)(q35;q31). Здоровые носители идентичной транслокации t(5;9)(q35;q31) были выявлены в трёх поколениях этой семьи. В статье описаны клинические проявления у пациента, обсуждаются возможные пути формирования такой хромосомной перестройки, а также проводится сравнительная характеристика фенотипических признаков на основе данных литературы. We report on a case of combined chromosomal pathology - partial trisomy on the terminal part of the long arm of chromosome 5 and partial trisomy on chromosome 9 in a newborn with multiple congenital malformations and karyotype 47,XY,t(5;9)(q35;q31),+der(9)t(5;9)(q35;q31)pat. The cause of the chromosomal pathology was a rare abnormality of the formation of gametes in the father’s meiosis II. He is the carrier of the autosomal reciprocal translocation t(5;9)(q35;q31). Healthy carriers of the identical t(5;9)(q35;q31) translocation were identified in three generations of this family. The clinical manifestations of the patient, the possible ways of forming the rearrangement of chromosomes, and the comparison of phenotypes based on the literature data are discussed.

Reconstructing the Climate Variability During the Last 5000 Years From the Banni Plains, Kachchh, Western India

The climatic conditions during the beginning of the last 5,000 years have been discussed, debated, and documented from various parts of the Indian subcontinent, due to the human–climate interrelationship. In the present study, we report a multi-proxy dataset encompassing the widely used ∼ geochemical and mineral magnetic proxies supported by radiocarbon and optical chronologies from the Banni Plains of the Rann of Kachchh, western India. Our results support the earlier observations of the prolonged wetter climatic condition synchronous with the mature phase of Harappan era which witnessed a short and intense arid condition at the terminal part of the mature Harappan phase. The climate system dramatically fluctuated during the last five millennia from pulsating between relatively arid (4,800–4,400 years BP, 3,300–3,000 years BP, and at 2,400 years BP) and relatively humid phases (>4,800 years BP, 4,000–3,300 years BP, 1900–1,400 years BP, and 900–550 years BP). The multi-proxy dataset shows a gradual strengthening of the monsoonal conditions from the Banni Plains during the late Harappan phase. Apart from this, the high sedimentation rate (>1 mm/yr) recorded from the Banni Plains suggests it can be tapped as a robust archive to reconstruct multi-decadal to centennial climatic events spanning the Holocene epoch.

Catalytic cycling of human mitochondrial Lon protease

The mitochondrial Lon protease homolog (LonP1) hexamer controls mitochondrial health by digesting proteins from the mitochondrial matrix that are damaged or must be removed. Understanding how it is regulated requires characterizing its mechanism. Here, we show how human LonP1 functions, based on eight different conformational states that we determined by cryo-EM with a resolution locally extending to 3.6 Å for the best ordered states. LonP1 has a poorly ordered N-terminal part with apparent threefold symmetry, which apparently binds substrate protein and feeds it into its AAA+ unfoldase core. This translocates the extended substrate protein into a proteolytic cavity, in which we report an additional, previously unidentified Thr-type proteolytic center. Threefold rocking movements of the flexible N-terminal assembly likely assist thermal unfolding of the substrate protein. Our data suggest LonP1 may function as a sixfold cyclical Brownian ratchet controlled by ATP hydrolysis.

A bacteriocin-based treatment option for Staphylococcus haemolyticus biofilms

Bacteriocins are ribosomally-synthesized antimicrobial peptides, showing great potential as novel treatment options for multidrug-resistant pathogens. In this study, we designed a novel hybrid bacteriocin, Hybrid 1 (H1), by combing the N-terminal part and the C-terminal part of the related bacteriocins enterocin K1 (K1) and enterocin EJ97 (EJ97), respectively. Like the parental bacteriocins, H1 used the membrane-bound protease RseP as receptor, however, it differed from the others in the inhibition spectrum. Most notably, H1 showed a superior antimicrobial effect towards Staphylococcus haemolyticus—an important nosocomial pathogen. To avoid strain-dependency, we further evaluated H1 against 27 clinical and commensal S. haemolyticus strains, with H1 indeed showing high activity towards all strains. To curtail the rise of resistant mutants and further explore the potential of H1 as a therapeutic agent, we designed a bacteriocin-based formulation where H1 was used in combination with the broad-spectrum bacteriocins micrococcin P1 and garvicin KS. Unlike the individual bacteriocins, the three-component combination was highly effective against planktonic cells and completely eradicated biofilm-associated S. haemolyticus cells in vitro. Most importantly, the formulation efficiently prevented development of resistant mutants as well. These findings indicate the potential of a bacteriocins-based formulation as a treatment option for S. haemolyticus.

Mapping of Functional Subdomains in the atALKBH9B m6A-Demethylase Required for Its Binding to the Viral RNA and to the Coat Protein of Alfalfa Mosaic Virus

N6-methyladenosine (m6A) modification is a dynamically regulated RNA modification that impacts many cellular processes and pathways. This epitranscriptomic methylation relies on the participation of RNA methyltransferases (referred to as “writers”) and demethylases (referred to as “erasers”), respectively. We previously demonstrated that the Arabidopsis thaliana protein atALKBH9B showed m6A-demethylase activity and interacted with the coat protein (CP) of alfalfa mosaic virus (AMV), causing a profound impact on the viral infection cycle. To dissect the functional activity of atALKBH9B in AMV infection, we performed a protein-mapping analysis to identify the putative domains required for regulating this process. In this context, the mutational analysis of the protein revealed that the residues between 427 and 467 positions are critical for in vitro binding to the AMV RNA. The atALKBH9B amino acid sequence showed intrinsically disordered regions (IDRs) located at the N-terminal part delimiting the internal AlkB-like domain and at the C-terminal part. We identified an RNA binding domain containing an RGxxxRGG motif that overlaps with the C-terminal IDR. Moreover, bimolecular fluorescent experiments allowed us to determine that residues located between 387 and 427 are critical for the interaction with the AMV CP, which should be critical for modulating the viral infection process. Finally, we observed that atALKBH9B deletions of either N-terminal 20 residues or the C-terminal’s last 40 amino acids impede their accumulation in siRNA bodies. The involvement of the regions responsible for RNA and viral CP binding and those required for its localization in stress granules in the viral cycle is discussed.