Factor XII Structure-Function Relationships

Factor XII (FXII), the zymogen of the protease FXIIa, contributes to pathologic processes such as bradykinin-dependent angioedema and thrombosis through its capacity to convert the homologs prekallikrein and factor XI to the proteases plasma kallikrein and factor XIa. FXII activation and FXIIa activity are enhanced when the protein binds to a surface. Here, we review recent work on the structure and enzymology of FXII with an emphasis on how they relate to pathology. FXII is a homolog of pro-hepatocyte growth factor activator (pro-HGFA). We prepared a panel of FXII molecules in which individual domains were replaced with corresponding pro-HGFA domains and tested them in FXII activation and activity assays. When in fluid phase (not surface bound), FXII and prekallikrein undergo reciprocal activation. The FXII heavy chain restricts reciprocal activation, setting limits on the rate of this process. Pro-HGFA replacements for the FXII fibronectin type 2 or kringle domains markedly accelerate reciprocal activation, indicating disruption of the normal regulatory function of the heavy chain. Surface binding also enhances FXII activation and activity. This effect is lost if the FXII first epidermal growth factor (EGF1) domain is replaced with pro-HGFA EGF1. These results suggest that FXII circulates in blood in a "closed" form that is resistant to activation. Intramolecular interactions involving the fibronectin type 2 and kringle domains maintain the closed form. FXII binding to a surface through the EGF1 domain disrupts these interactions, resulting in an open conformation that facilitates FXII activation. These observations have implications for understanding FXII contributions to diseases such as hereditary angioedema and surface-triggered thrombosis, and for developing treatments for thrombo-inflammatory disorders.

Emotional and Behavioral Problems of Children with ASD-The Lessons That We Learned from the Pandemic

The data available for changes in the behavior and emotional state of children with ASD (autism spectrum disorder) in lockdown situations are controversial and scarce. In our research, we compare results before the first COVID-19 lockdown of 21 children with ASD and 21 typically developing children, four to five years of age with those obtained immediately after. The study attempts to answer the question of whether there are changes in the levels of emotional and behavioral problems in children with ASD after the lockdown and how these new living conditions affect some aspects of their functioning. The instruments used for data analysis are the Childhood Autism Spectrum Test (CAST); Child Behavior Checklist (CBCL); Survey on the consequences of COVID-19 on the life and development of the participants. No significant differences in the emotional and behavioral state of the participants were found, except for attention deficit/hyperactivity problems where ASD children showed lower levels after the lockdown. ASD group parents' answers to the survey pointed towards more positive consequences of staying at home. Some reported they had more time for learning together, communicating, playing, and assisting the learning process through online therapy. As negatives, the parents of ASD children reported low physical activity, increased time with electronic devices, and time spent with the same people. Caregivers of typically developing children agreed that the lockdown had only negative effects. To conclude, for children with ASD in the study, the lockdown period demonstrated that more time spent with parents in structured everyday activities is an opportunity that can lead to positive results in their behavior.

Mechanisms involved in hereditary angioedema with normal C1-inhibitor activity

Patients with the inherited disorder hereditary angioedema (HAE) suffer from episodes of soft tissue swelling due to excessive bradykinin production. In most cases, dysregulation of the plasma kallikrein-kinin system due to deficiency of plasma C1 inhibitor is the underlying cause. However, at least 10% of HAE patients have normal plasma C1 inhibitor activity levels, indicating their syndrome is the result of other causes. Two mutations in plasma protease zymogens that appear causative for HAE with normal C1 inhibitor activity have been identified in multiple families. Both appear to alter protease activity in a gain-of-function manner. Lysine or arginine substitutions for threonine 309 in factor XII introduces a new protease cleavage site that results in formation of a truncated factor XII protein (Δ-factor XII) that accelerates kallikrein-kinin system activity. A glutamic acid substitution for lysine 311 in the fibrinolytic protein plasminogen creates a consensus binding site for lysine/arginine side chains. The plasmin form of the variant plasminogen cleaves plasma kininogens to release bradykinin directly, bypassing the kallikrein-kinin system. Here we review work on the mechanisms of action of the FXII-Lys/Arg309 and Plasminogen-Glu311 variants, and discuss the clinical implications of these mechanisms.

Fentanyl in an Infant: Taking Our Breath Away

Pediatric respiratory failure carries a wide differential diagnosis. Toxic ingestion should remain on the differential even at very young ages. There have been increasing reports of fentanyl overdoses among adults; however, this should be considered for accidental pediatric ingestion, especially considering its high potential for mortality. A nine-month-old female presented to the pediatric emergency department with respiratory failure. The patient was noted to be bradypneic with miotic pupils, and therefore, naloxone was given intravenously (IV) with a positive response. The patient required numerous boluses of intravenous naloxone, which ultimately saved her from intubation. The patient's laboratory results were later positive for fentanyl and cocaine. Fentanyl ingestion has a high mortality rate, especially in pediatrics. With increasing fentanyl use, there is a potential for exposure due to not only child abuse and intentional toxicity but also exploratory ingestions.

Not Your Typical Thunderclap Headache

We present the case of a young adult female who presented to the emergency department with headache and vomiting. After treatment with intravenous fluids, diphenhydramine and metoclopramide the headache completely resolved. Because of the patient's persistent symptoms and past medical history of systemic lupus erythematosus, a noncontrast head CT scan was done. In this case, the patient had a subarachnoid hemorrhage with edema and mass effect, detected on a noncontrast head CT scan. The patient required a nicardipine drip for blood pressure control. The patient recovered well and was discharged at her normal state of health. This case demonstrates the importance of maintaining high clinical suspicion for life-threatening emergencies even in patients with unremarkable physical exams who experience symptomatic improvement after treatment.

Short-chain fatty acid production in accessible and inaccessible body pools as assessed by novel stable tracer pulse approach is reduced by aging independent of presence of COPD

BACKGROUND

Production rates of the short-chain fatty acids (SCFA) acetate, propionate, and butyrate, which are beneficial metabolites of the intestinal microbiota, are difficult to measure in humans due to inaccessibility of the intestine to perform measurements, and the high first-pass metabolism of SCFAs in colonocytes and liver. We developed a stable tracer pulse approach to estimate SCFA whole-body production (WBP) in the accessible pool representing the systemic circulation and interstitial fluid. Compartmental modeling of plasma enrichment data allowed us to additionally calculate SCFA kinetics and pool sizes in the inaccessible pool likely representing the intestine with microbiota. We also studied the effects of aging and the presence of Chronic Obstructive Pulmonary Disease (COPD) on SCFA kinetics.

METHODS

In this observational study, we designed a two-compartmental model to determine SCFA kinetics in 31 young (20-29 y) and 71 older (55-87 y) adults, as well as in 33 clinically stable patients with moderate to very severe COPD (mean (SD) FEV₁, 46.5 (16.2)% of predicted). Participants received in the fasted state a pulse containing stable tracers of acetate, propionate, and butyrate intravenously and blood was sampled four times over a 30 min period. We measured tracer-tracee ratios by GC-MS and used parameters obtained from two-exponential curve fitting to calculate non-compartmental SCFA WBP and perform compartmental analysis. Statistics were done by ANCOVA.

RESULTS

Acetate, propionate, and butyrate WBP and fluxes between the accessible and inaccessible pools were lower in older than young adults (all q < 0.0001). Moreover, older participants had lower acetate (q < 0.0001) and propionate (q = 0.019) production rates in the inaccessible pool as well as smaller sizes of the accessible and inaccessible acetate pools (both q < 0.0001) than young participants. WBP, compartmental SCFA kinetics, and pool sizes did not differ between COPD patients and older adults (all q > 0.05). Overall and independent of the group studied, calculated production rates in the inaccessible pool were on average 7 (acetate), 11 (propionate), and 16 (butyrate) times higher than non-compartmental WBP, and sizes of inaccessible pools were 24 (acetate), 31 (propionate), and 55 (butyrate) times higher than sizes of accessible pools (all p < 0.0001).

CONCLUSION

Non-compartmental production measurements of SCFAs in the accessible pool (i.e. systemic circulation) substantially underestimate the SCFA production in the inaccessible pool, which likely represents the intestine with microbiota, as assessed by compartmental analysis.

Sternoclavicular Septic Arthritis: A Case Report

We report a case of a 47-year-old male who presented with concerns for a "mass" on the right side of his chest and low-grade fevers for the last month. The patient was found to have an induration, erythema, and warmth at the right sternoclavicular joint, with tenderness to palpation and pain in the movement of the right arm. The patient was found to have septic arthritis of the sternoclavicular joint based on CT imaging. Sternoclavicular joint septic arthritis is a rare diagnosis and accounts for very few diagnosed septic joints. Most patients have some sort of risk factors, such as diabetes, immunosuppression, rheumatoid arthritis, or intravenous drug use. The most common pathogen is Staphylococcus aureus. Our patient did not consent to joint aspiration for a definitive diagnosis of the causative organism and was therefore empirically treated for S. aureus with trimethoprim-sulfamethoxazole. The patient also did not consent to any surgical management. Septic arthritis has been successfully treated with antibiotic therapy alone in the past, and in conjunction with the patient's choices, this was the treatment plan that was chosen for the patient. The patient responded to antibiotic therapy and followed up with a thoracic surgery clinic outpatient. This case depicts the importance of retaining a high index of suspicion for a rare diagnosis in the emergency department (ED). This case also depicts the successful treatment of sternoclavicular septic arthritis with outpatient oral trimethoprim-sulfamethoxazole, which, to the best of our knowledge, has not been done previously.

Aryl Hydrocarbon Receptor (AhR) Signaling in Colonic Cells and Tumors

The aryl hydrocarbon receptor (AhR) is overexpressed in many tumor types and exhibits tumor-specific tumor promoter and tumor suppressor-like activity. In colon cancer, most but not all studies suggest that the AhR exhibits tumor suppressor activity which is enhanced by AhR ligands acting as agonists. Our studies investigated the role of the AhR in colon tumorigenesis using wild-type and AhR-knockout mice, the inflammation model of colon tumorigenesis using mice treated with azoxymethane (AOM)/dextran sodium sulfate (DSS) and APCS580/+; KrasG12D/+ mice all of which form intestinal tumors. The effects of tissue-specific AhR loss in the intestine of the tumor-forming mice on colonic stem cells, organoid-initiating capacity, colon tumor formation and mechanisms of AhR-mediated effects were investigated. Loss of AhR enhanced stem cell and tumor growth and in the AOM/DSS model AhR-dependent suppression of FOXM1 and downstream genes was important for AhR-dependent anticancer activity. Furthermore, the effectiveness of interleukin-22 (IL22) in colonic epithelial cells was also dependent on AhR expression. IL22 induced phosphorylation of STAT3, inhibited colonic organoid growth, promoted colonic cell proliferation in vivo and enhanced DNA repair in AOM/DSS-induced tumors. In this mouse model, the AhR suppressed SOCS3 expression and enhanced IL22-mediated activation of STAT3, whereas the loss of the AhR increased levels of SOCS3 which in turn inhibited IL22-induced STAT3 activation. In the APCS580/+; KrasG12D/+ mouse model, the loss of the AhR enhanced Wnt signaling and colon carcinogenesis. Results in both mouse models of colon carcinogenesis were complemented by single cell transcriptomics on colonic intestinal crypts which also showed that AhR deletion promoted expression of FOXM1-regulated genes in multiple colonic cell subtypes. These results support the role of the AhR as a tumor suppressor-like gene in the colon.

A Mathematical Model for Rationality in Timetable Planning

The preparation of a study timetable (or schedule) depends on the school or university for which it is made and on the specific work practices applied in this educational institution. The preparation of a school timetable in a school or university aims to plan for the conduct of classes in certain academic disciplines for a certain period of time, while optimally engaging the classrooms and professors available for the relevant period. The aim of this paper is to provide a mathematical model for rationality in planning a study timetable. This mean to make forecast on whether the accepted number of students, organised in groups, could be instructed during defined period of time in the available classrooms in the educational institution. The developed model aims to make better use of available classrooms and places for students in them. Calculating a rationality ratio will give the educational institution an idea of the:  Need for more classrooms;  Need to extend the study period (number of days for the planned semester)  Need for more optimal planning of the study timetable and better use to the rooms. The prepared model also includes a coefficient of specific rationality, in case the educational institution has classrooms of different capacities - for lectures and practical exercises. The developed mathematical model can be useful to higher education institutions for the purpose of planning their educational activity and it can be applied before the actual process of planning a study schedule. The data used and calculations results serve as the basis for an in-depth analysis related to the requirements for the educational process and the opportunities provided by the educational institution.

Design of the Building Research in CRC prevention (BRIDGE-CRC) trial: a 6-month, parallel group Mediterranean diet and weight loss randomized controlled lifestyle intervention targeting the bile acid-gut microbiome axis to reduce colorectal cancer risk among African American/Black adults with obesity

BACKGROUND

Among all racial/ethnic groups, people who identify as African American/Blacks have the second highest colorectal cancer (CRC) incidence in the USA. This disparity may exist because African American/Blacks, compared to other racial/ethnic groups, have a higher prevalence of risk factors for CRC, including obesity, low fiber consumption, and higher intakes of fat and animal protein. One unexplored, underlying mechanism of this relationship is the bile acid-gut microbiome axis. High saturated fat, low fiber diets, and obesity lead to increases in tumor promoting secondary bile acids. Diets high in fiber, such as a Mediterranean diet, and intentional weight loss may reduce CRC risk by modulating the bile acid-gut microbiome axis. The purpose of this study is to test the impact of a Mediterranean diet alone, weight loss alone, or both, compared to typical diet controls on the bile acid-gut microbiome axis and CRC risk factors among African American/Blacks with obesity. Because weight loss or a Mediterranean diet alone can reduce CRC risk, we hypothesize that weight loss plus a Mediterranean diet will reduce CRC risk the most.

METHODS

This randomized controlled lifestyle intervention will randomize 192 African American/Blacks with obesity, aged 45-75 years to one of four arms: Mediterranean diet, weight loss, weight loss plus Mediterranean diet, or typical diet controls, for 6 months (48 per arm). Data will be collected at baseline, mid-study, and study end. Primary outcomes include total circulating and fecal bile acids, taurine-conjugated bile acids, and deoxycholic acid. Secondary outcomes include body weight, body composition, dietary change, physical activity, metabolic risk, circulating cytokines, gut microbial community structure and composition, fecal short-chain fatty acids, and expression levels of genes from exfoliated intestinal cells linked to carcinogenesis.

DISCUSSION

This study will be the first randomized controlled trial to examine the effects of a Mediterranean diet, weight loss, or both on bile acid metabolism, the gut microbiome, and intestinal epithelial genes associated with carcinogenesis. This approach to CRC risk reduction may be especially important among African American/Blacks given their higher risk factor profile and increased CRC incidence.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04753359 . Registered on 15 February 2021.

Protein Amadoriase Activity of the Escherichia coli K-12 Glycolytic Enzyme Phosphoglucose Isomerase

The Maillard reaction (glycation) is a spontaneous non-enzymatic reaction between primary amines and carbonyl compounds, which affects proteins and DNA of both pro- and eukaryotes. In recent studies, we have shown that the glycolytic enzyme of Escherichia coli phosphoglucose isomerase (PGI) catalyzes in vitro the deglycation of DNA modified with glucose 6-phosphate (G6P)-derived Amadori products (APs). APs are early products of the Maillard reaction, which are formed not only on DNA but also on other amines including proteins. The aim of the current study was to test the E. coli PGI for protein deglycation (amadoriase) activity. To this end, we used chicken lysozyme glycated with G6P as a model protein. Treatment of the glycated lysozyme with protein extract from an E. coli PGI proficient but not deficient strain resulted in the release of G6P, which was indicative of PGI protein amadoriase activity. G6P-derived APs represent fructose 6-phosphate (F6P) residues bound to free amino groups of the model protein and because of that we compared the kinetic constants of the E. coli PGI for the glycated lysozyme and for free F6P. PGI demonstrated nearly two times higher affinity to the glycated lysozyme (Km' = 0.06 mM) than to free F6P (Km' = 0.1 mM). However, the apparent catalytic constant of the enzyme with the glycated lysozyme (Kcat' = 93 s–1) was eight times lower than with F6P (Kcat' = 736 s–1). Future studies are expected to shed light on the physiological relevance of the PGI protein amadoriase activity we report here.

Hypomyelination with Atrophy of Basal Ganglia and Cerebellum (HABC) Due to UFM1 Mutation in Roma Patients - Severe Early Encephalopathy with Stridor and Severe Hearing and Visual Impairment. A Single Center Experience

BACKGROUND

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a neurodegenerative disease with neurodevelopmental delay, motor, and speech regression, pronounced extrapyramidal syndrome, and sensory deficits due to TUBB4A mutation. In 2017, a severe variant was described in 16 Roma infants due to mutation in UFM1.

OBJECTIVE

The objective of this study is to expand the clinical manifestations of H-ABC due to UFM1 mutation and suggest clues for clinical diagnosis.

METHODOLOGY

Retrospective analysis of all 9 cases with H-ABC due to c.-273_-271delTCA mutation in UFM1 treated during 2013-2020 in a Neuropediatric Ward in Plovdiv, Bulgaria.

RESULTS

Presentation is no later than 2 months with inspiratory stridor, impaired sucking, swallowing, vision and hearing, and reduced active movements. By the age of 10 months, a monomorphic disease was observed: microcephaly (6/9), malnutrition (5/9), muscle hypertonia (9/9) and axial hypotonia (4/9), progressing to opisthotonus (6/9), dystonic posturing (5/9), nystagmoid ocular movements (6/9), epileptic seizures (4/9), non-epileptic spells (3/9). Dysphagia (7/9), inspiratory stridor (9/9), dyspnea (5/9), bradypnea (5/9), apnea (2/9) were major signs. Vision and hearing were never achieved or lost by 4-8 mo. Neurodevelopment was absent or minimal with subsequent regression after 2-5 mo. Brain imaging revealed cortical atrophy (7/9), atrophic ventricular dilatation (4/9), macrocisterna magna (5/9), reduced myelination (6/6), corpus callosum atrophy (3/6) and abnormal putamen and caput nuclei caudati. The age at death was between 8 and 18 mo.

CONCLUSION

Roma patients with severe encephalopathy in early infancy with stridor, opisthotonus, bradypnea, severe hearing and visual impairment should be tested for the Roma founder mutation of H-ABC in UFM1.

Surgical treatment of endo-periodontal lesion - а case report

The interrelationship between periodontium and pulp makes the treatment of combined endo-periodontal lesions (EPL) more challenging. It involves successful elimination of both periodontal and endodontic lesion. The current case report represents the efficacy of regenerative potential of enamel matrix derivates (Emdogain®) in endo-periodontal lesion after successful endodontic treatment. A 39-year-old woman presented with EPL on a left first mandibular molar. After the initial 3 months of healing, the clinical examination showed that the furcation involvement still prevailed. A decision was made to use a regenerative procedure using Emdogain®. Fourteen months after the procedure, full periodontal regeneration can be seen on the X-ray. The results demonstrated the synergetic effect of the endodontic and periodontal therapy that changed the prognosis for the tooth.

Thermochemical Study of CH3NH3Pb(Cl1-xBrx)3 Solid Solutions

Hybrid organic-inorganic perovskite halides, and, in particular, their mixed halide solid solutions, belong to a broad class of materials which appear promising for a wide range of potential applications in various optoelectronic devices. However, these materials are notorious for their stability issues, including their sensitivity to atmospheric oxygen and moisture as well as phase separation under illumination. The thermodynamic properties, such as enthalpy, entropy, and Gibbs free energy of mixing, of perovskite halide solid solutions are strongly required to shed some light on their stability. Herein, we report the results of an experimental thermochemical study of the CH₃NH₃Pb(Cl_1-xBr_x)₃ mixed halides by solution calorimetry. Combining these results with molecular dynamics simulation revealed the complex and irregular shape of the compositional dependence of the mixing enthalpy to be the result of a complex interplay between the local lattice strain, hydrogen bonds, and energetics of these solid solutions.

APPLICATION OF PLATELET RICH FIBRIN IN SURGICAL PERIODONTAL THERAPY: A CONTROLLED CLINICAL TRIAL

Purpose: The current study investigates the effectiveness of two surgical protocols for the treatment of periodontitis (Stage III or Stage IV) in the presence of angular bone defects. Materials and methods: Twenty patients diagnosed with periodontitis were randomly divided into two groups, each of 10 patients with radiographically proven infraosseous defects. The first group delivered surgical treatment with bone graft and platelet rich fibrin, the second group – only with bone graft. Clinical and radiographic parameters were assessed before and 6 months after the surgical procedure. Results: Statistically significant differences were found between both groups in the following parameters: probing pocket depth, clinical attachment gain, bone filling, and radiographic depth of the bone defect before and after periodontal surgery, described as bone filling in millimeters. Conclusion: The results show platelet rich fibrin as an autogenous material with promising potential. Its additional application to bone replacement materials can improve the clinical parameters and the expected filling of the vertical bone defects.

Association of NGF and Mitochondrial Respiration with Autism Spectrum Disorder

Background: NGF is a molecule with a pleiotropic role, affecting neuro-immune functions, energy homeostasis, and synaptic plasticity. The mechanisms of NGF-induced neuronal differentiation are well established, but its effect on mitochondria in autism spectrum disorder (ASD) is still unclear. We hypothesize that NGF-induced neuronal development requires large amounts of energy, and mitochondria in ASD are overloaded to meet the new functional requirements. Method: The study includes primary diagnosed ASD children. Peripheral blood mononuclear cells (PBMCs) and plasma were obtained from both patients and typically developing children (TDC). PBMCs were analyzed with Seahorse XFp, and plasma NGF protein levels were measured. Results: We detected nearly 50% higher NGF levels and approximately 40% elevation in spare respiratory capacity in ASD compared to TDC. These findings are consistent with the observed difference in maximal respiration, which was also significantly higher in the patient group. Both mitochondrial respiration and NGF plasma levels exhibit a strong potential to discriminate children with ASD from TDC. Conclusions: This study is the first to link elevated NGF with mitochondrial respiration and altered energy homeostasis in ASD. High NGF correlates with basic bioenergetic signatures that may be used as a screening tool to improve early diagnosis and clinical follow-up in ASD.

Hetero-Multivalent Targeted Liposomal Drug Delivery to Treat Pseudomonas aeruginosa Infections

Pseudomonas aeruginosa is the leading nosocomial and community-acquired pathogen causing a plethora of acute and chronic infections. The Centers for Disease Control and Prevention has designated multidrug-resistant isolates of P. aeruginosa as a serious threat. A novel delivery vehicle capable of specifically targeting  P. aeruginosa, and encapsulating antimicrobials, may address the challenges associated with these infections. We have developed hetero-multivalent targeted liposomes functionalized with host cell glycans to increase the delivery of antibiotics to the site of infection. Previously, we have demonstrated that compared with monovalent liposomes, these hetero-multivalent liposomes bind with higher affinity to P. aeruginosa. Here, compared with nontargeted liposomes, we have shown that greater numbers of targeted liposomes are found in the circulation, as well as at the site of P. aeruginosa (PAO1) infection in the thighs of CD-1 mice. No significant difference was found in the uptake of targeted, nontargeted, and PEGylated liposomes by J774.A1 macrophages. Ciprofloxacin-loaded liposomes were formulated and characterized for size, encapsulation, loading, and drug release. In vitro antimicrobial efficacy was assessed using CLSI broth microdilution assays and time-kill kinetics. Lastly, PAO1-inoculated mice treated with ciprofloxacin-loaded, hetero-multivalent targeted liposomes survived longer than mice treated with ciprofloxacin-loaded, monovalent targeted, or nontargeted liposomes and free ciprofloxacin. Thus, liposomes functionalized with host cell glycans target P. aeruginosa resulting in increased retention of the liposomes in the circulation, accumulation at the site of infection, and increased survival time in a mouse surgical site infection model. Consequently, this formulation strategy may improve outcomes in patients infected with P. aeruginosa.

Lymphoepithelioma-like Carcinoma of the Breast Synchronous with a High-Grade Invasive Ductal Carcinoma and Ductal Carcinoma in Situ in a Different Quadrant of the Same Breast: A Case Report

Lymphoepithelioma-like breast carcinoma (LELC) is a rare type of malignant breast tumor that is not included in the current edition of the World Health Organization (WHO) classification of breast tumors. Currently, there are no clearly defined therapeutic strategies, and the general information on breast LELC is based on sporadic clinical cases described in the medical literature. We present a clinical case that describes a 49-year-old woman with a tumor formation in the right breast, histologically verified as LELC, together with a non-palpable, synchronous high-grade invasive ductal carcinoma and ductal carcinoma in situ Grade 2 (DCIS G2) in a different quadrant of the same breast. To our knowledge, this is the first case described in the literature that combines a LELC with a synchronous carcinoma in the same breast.

Initial introduction and spread of the SARS-CoV-2 AY.4.2.1 Delta variant in Bulgaria, a genomic insight

The evolution of the emerging SARS-CoV-2 variants carrying mutations in the spike protein raises concerns about the possibility of accelerated transmission in the ever-evolving COVID-19 pandemic worldwide. AY.4.2, a sublineage of the Delta variant, was considered a variant under investigation (VUI) and also gained the nickname "Delta Plus," due to its extra mutations, Y145H and A222V. In this study, using genomic epidemiology, we provide the first insights into the introduction of AY.4.2 in Bulgaria and the AY.4.2.1 sublineage that found larger dissemination only in Bulgaria and the United Kingdom.

Temporal characterization of a two-color laser field using tunneling ionization

The superposition of a fundamental laser pulse and its second harmonic can form an asymmetric laser field that is useful in many applications. The temporal characterization of the two-color laser field becomes necessary. However, the temporal characterization of the two-color laser pulse is a challenging task due to its broad bandwidth and a spectral gap between the two frequency components. Here we demonstrate the temporal characterization of the two-color laser field using multiple ionization yield measurements near the laser focus. This new approach enables the complete temporal characterization of the two-color laser field, including the relative phase between the two frequency components.

Transcriptomic Profiling of Gene Expression Associated with Granulosa Cell Tumor Development in a Mouse Model

Ovarian granulosa cell tumors (GCTs) are rare sex cord-stromal tumors, accounting for ~5% ovarian tumors. The etiology of GCTs remains poorly defined. Genetically engineered mouse models are potentially valuable for understanding the pathogenesis of GCTs. Mice harboring constitutively active TGFβ signaling (TGFBR1-CA) develop ovarian GCTs that phenocopy several hormonal and molecular characteristics of human GCTs. To determine molecular alterations in the ovary upon TGFβ signaling activation, we performed transcriptomic profiling of gene expression associated with GCT development using ovaries from 1-month-old TGFBR1-CA mice and age-matched controls. RNA-sequencing and bioinformatics analysis coupled with the validation of select target genes revealed dysregulations of multiple cellular events and signaling molecules/pathways. The differentially expressed genes are enriched not only for known GCT-related pathways and tumorigenic events but also for signaling events potentially mediated by neuroactive ligand-receptor interaction, relaxin signaling, insulin signaling, and complements in TGFBR1-CA ovaries. Additionally, a comparative analysis of our data in mice with genes dysregulated in human GCTs or granulosa cells overexpressing a mutant FOXL2, the genetic hallmark of adult GCTs, identified some common genes altered in both conditions. In summary, this study has revealed the molecular signature of ovarian GCTs in a mouse model that harbors the constitutive activation of TGFBR1. The findings may be further exploited to understand the pathogenesis of a class of poorly defined ovarian tumors.

In vitro Investigation of Antibiotic Combinations against Multi- and Extensively Drug-Resistant Klebsiella pneumoniae

Objectives: Community and hospital acquired K. pneumoniae infections have become a ubiquitous medical issue due to the limited treatment options and high mortality rate therefore the aims of this study are in vitro investigation of double antimicrobial combinations against multidrug resistant (MDR) and extensively drug resistant (XDR) isolates. Materials and Methods: Antimicrobial susceptibility of twelve isolates from eight Bulgarian hospitals was determined to study the interaction effect of selected double combinations in accordance to fractional inhibitory concentration (FIC) method. Furthermore, the isolates were subjected to genotyping by Multilocus sequence typing (MLST) and detection of carbapenemase genes by multiplex PCR. The results were assessed by groups of strains with either NDM or KPC carbapenemase. Results: Nine antimicrobial combinations: meropenem-colistin, meropenem-fosfomycin, meropenem-gentamicin, meropenem-rifampicin, meropenem-tigecycline, colistin-fosfomycin, colistin-gentamicin, colistin-rifampicin and colistin-tigecycline were tested for synergism on twelve K. pneumoniae, producing either KPC-2 (KPC-KP, 41.7%, 5/12) or NDM-1 (NDM-KP, 58.3%, 7/12). The isolates were distributed in three sequence types: ST11 (58.3%, 7/12), ST15 (25%, 3/12) and ST258 (16.7%, 2/12). All KPC-KP (ST258 and ST15) originated from three hospitals. The rest were NDM-1 carriers isolated from six hospitals and belonged to ST11. The highest synergistic effect was determined for MER-GEN (83.3%, 10/12) and COL-RIF (83.3%, 10/12). The MER-FOS combination was most efficient against NDM-KP, opposite to the KPC strains. Antagonism was not observed for any combinations. Conclusions: The evaluated joint synergistic effect of the MER-GEN and COL-RIF may facilitate the treatment options for patients infected with NDM- and KPC-KP, whereas MER-FOS is highly synergetic against NDM-KP.