Intestinal microbiome changes in an infant with right atrial isomerism and recurrent necrotizing enterocolitis: A case report and review of literature

BACKGROUNDNecrotizing enterocolitis (NEC) is a multifactorial disease that predominantly affects premature neonates. Intestinal dysbiosis plays a critical role in NEC pathogenesis in premature neonates. The main risk factor for NEC in term infants is mesenteric hypoperfusion associated with ductal-dependent congenital heart disease (CHD) that eventually leads to intestinal ischemia. The incidence of NEC in neonates with critical CHD is 6.8%-13%. However, the role of the intestinal microbiome in NEC pathogenesis in infants with ductal-dependent CHD remains unclear.CASE SUMMARYA male term neonate with right atrial isomerism underwent modified Blalock-Taussig shunt placement on the 14^th day of life and had persistent mesenteric hypoperfusion after surgery. The patient had episodes of NEC stage IIA on the 1^st and 28^th days after cardiac surgery. Fecal microbial composition was analyzed before and after cardiac surgery by sequencing region V4 of the 16S rRNA gene. Before surgery, species belonging to genera Veillonella and Clostridia and class Gammaproteobacteria were detected, Bifidobacteriaceae showed a low abundance. The first NEC episode was associated with postoperative hemodynamic instability, intestinal ischemia-reperfusion injury during cardiopulmonary bypass, and a high abundance of Clostridium paraputrificum (Clostridium sensu stricto I) (56.1%). Antibacterial therapy after the first NEC episode resulted in increased abundance of Gammaproteobacteria, decreased abundance of Firmicutes, and low alpha diversity. These changes in the microbial composition promoted the growth of Clostridium sensu stricto I (72.0%) before the second NEC episode.CONCLUSIONA high abundance of Clostridium sensu stricto I and mesenteric hypoperfusion may have contributed to NEC in the present case.     

Ladder-like amplification of the type I interferon gene cluster in the human osteosarcoma cell line MG63

The organization of the type I interferon (IFN) gene cluster (9p21.3) was studied in a human osteosarcoma cell line (MG63). Array comparative genomic hybridization (aCGH) showed an amplification of ∼6-fold which ended at both ends of the gene cluster with a deletion that extended throughout the 9p21.3 band. Spectral karyotyping (SKY) combined with fluorescence in-situ hybridization (FISH) identified an arrangement of the gene cluster in a ladder-like array of 5–7 ‘bands’ spanning a single chromosome termed the ‘IFN chromosome’. Chromosome painting revealed that the IFN chromosome is derived from components of chromosomes 4, 8 and 9. Labelling with centromeric probes demonstrated a ladder-like amplification of centromeric 4 and 9 sequences that co-localized with each other and a similar banding pattern of chromosome 4, as well as alternating with the IFN gene clusters. In contrast, centromere 8 was not detected on the IFN chromosome. One of the amplified centromeric 9 bands was identified as the functional centromere based on its location at the chromosome constriction and immunolocalization of the CENP-C protein. A model is presented for the generation of the IFN chromosome that involves breakage–fusion–bridge events. Electronic supplementary material   The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Contact dermatitis to white petrolatum

A 31-year-old Caucasian woman presented with a 20-year history of presumed atopic dermatitis. She complained of severe pruritus and the presence of extensive patches of erythema and scale. Her previous treatments included: multiple topical corticosteroids, tacrolimus 0.1% ointment, pimecrolimus 1% cream, and cyclosporine with no improvement of her symptoms. Her past medical history was unremarkable and she was on no other oral medications, including over-the-counter products. On physical examination, multiple erythematous, scaly patches were present on the chest, abdomen,back, and upper extremities. Lichenification of both antecubital fossa was present. Extensive excoriations on her arms and abdomen were also noted. Although the patient had a long-standing history of presumed atopic dermatitis, she had never undergone a skin biopsy. A skin biopsy was performed which demonstrated a perivascular lymphocytic infiltrate with eosinophils and dermal edema (Figures 1, 2). The biopsy was suggestive of possible hypersensitivity dermatitis. The patient then underwent patch testing. The following patch tests were applied to normal back skin using IQ chambers:North American Contact Dermatitis Group (NACDG) expanded standard, textile, fragrance trays, and ingredients found in her products (Chemotechnique, Malmo, Sweden). A total of 89 patches were applied, removed at 48 hours, and read both at 48 and 96 hours. At 48 hours, a total of 70 allergens were positive, 69 of those allergens were in a petrolatum vehicle. There were 50, 3+ reactions to sites of allergens in petrolatum (Figure 3). There were only two sites with petrolatum that were negative: budesonide (a corticosteroid) and melamine formaldehyde. In contrast, all of the sites where there were allergens in liquid vehicles were negative, with the exception of a 1+ reaction to cocamidopropyl betaine. At 48 hours,four additional patch tests were applied to plain petrolatum. Two of these patches were in plastic IQ chambers and two in aluminum Finn Chambers. At 48 hours, all four of the sites showed 3+ reactions (Figure 4). By 96 hours, all of the patch test sites that were positive at 48 hours, and much of the surrounding skin, showed a diffuse "angry back" reaction, which made an accurate 96-hour reading impossible.     

Tb-based silicate apatites showing slow magnetization relaxation with identical parameters for the Tb3+ and Dy3+ counter ions

Tb-diluted and Tb-rich apatite-type silicates with compositions Y_7.75Tb_0.25Ca₂(SiO₄)₆O₂ and Tb₈Ca₂(SiO₄)₆O₂, respectively, exhibit field induced multiple slow relaxation of magnetization. The former reveals two slow relaxation paths, the latter only one with a longer relaxation time of several seconds. The relaxation features of the Tb-diluted one are comparable with those of analogue compounds, where Tb is replaced by Dy, as well as with those of a Tb-doped calcium phosphate apatite. The relaxation parameters of the Tb-rich compound virtually match those of the Dy-based analogue Dy₈Ca₂(SiO₄)₆O₂. The latter represents the first instance of independence of magnetization relaxation on the nature of a paramagnetic rare-earth metal ion in single ion magnet like materials.

Replacing Dy³⁺ with Tb³⁺ in the apatite-type silicate (Dy,Y)₈Ca₂(SiO₄)₆O₂ preserves the character of the magnetization slow relaxation.     

Synthesis and Properties of SrTiO3 Ceramic Doped with Sm2O3

The aim of this work was to study the effect of samarium oxide doping on a SrTiO₃ perovskite ceramic. After analyzing the data obtained on the morphological features of the synthesized structures, it was found that an increase in the dopant concentration led not only to a change in the morphological features, but also in the density of the ferroelectrics. Using the X-ray diffraction method, it was found that doping with Sm₂O₃ led to the formation of a multiphase system of two cubic phases of SrTiO₃ and Sm₂O₃. At the same time, an increase in the concentration of Sm₂O₃ dopant led to a change in the crystallinity degree, as well as deformation of the structure. Evaluation of the efficiency of use of synthesized ferroelectrics as catalysts for purification of aqueous media from manganese showed that an increase in the concentration of Sm₂O₃ dopant led to an increase in purification efficiency by 50–70%.     

The Theory of Similarity and Analysis of Dimensions for Determining the State of Operation of Structures under Difficult Loading Conditions

A simulation mathematical model of the state of operability of metal structures under difficult operating conditions without stopping the equipment was developed in the form of similarity criteria found on the basis of the laws of conservation of data obtained experimentally during tensile and four-point bending tests. Criteria are proposed for the similarity of the state of the material of the samples and the products in service, in which the kinetics of destruction are determined through the rate of damage accumulation and the movement of the structural components of the material. The residual life of the equipment under conditions of complex deformation effects was determined based on the theory of similarity and the analysis of the dimensions of the parameters of acoustic emission in real time. The use of concepts and models of fracture mechanics when creating methods and criteria for assessing the results of diagnostics and monitoring allows important information about the technical state of objects to be obtained.     

Re(i)-nitroxide complexes

Spin-labeled cyrhetrenes [(NNCp)Re(CO)₃] and [(INCp)Re(CO)₃], where NNCp is nitronyl nitroxide 2-(η⁵-cyclopentadienyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl and INCp is the corresponding imino nitroxide, were synthesized and characterized by EPR, CV, XRD, magnetochemistry and quantum chemistry methods. The correlations between different arrangements of paramagnetic centers and the magnetic exchange interactions for three polymorphs of [(NNCp)Re(CO)₃] were studied. It was concluded that high kinetic stability of nitroxide-substituted cyrhetrenes is a promising feature of compounds for the creation of multifunctional contrast agents.

Stable nitroxide-substituted cyrhetrenes were synthesized and characterized by EPR, CV, XRD, magnetochemistry and quantum chemistry methods.     

Reduced wall compliance suppresses Akt-dependent apoptosis protection stimulated by pulse perfusion

Reduced arterial compliance and increased pulse pressure are common and major risk factors for cardiovascular disease. Here, we reveal a novel mechanism whereby loss of wall distensibility blunts endothelial cell protection to oxidant stress-induced apoptosis. Bovine aortic endothelial cells cultured in compliant or stiff silastic tubes were pulse perfused by arterial pressure/flow waveforms generated by a servo-pump. Pulse perfusion induced time-dependent Akt activation peaking >6-fold after 2 hours in compliant tubes and a similar time course but half the magnitude in stiff tubes. This was accompanied by quantitatively similar disparities in phosphoinositide-3 kinase activation and in Akt-stimulated suppressors of apoptosis: glycogen synthase kinase-3beta, forkhead, and Bad. Cells perfused in compliant tubes had twice the protection against H2O2-stimulated apoptosis than those in stiffer tubes. This protection was lost by pretreatment with an Akt inhibitor and restored in cells transfected with myristoylated Akt yet perfused in stiff tubes. Shear and stretch Akt signaling coupled to different upstream pathways as inhibition of vascular endothelial growth factor receptor 2 (VEGF2R) or disruption of caveolae blocked steady and pulse flow-mediated activation, yet did not suppress phosphorylated Akt induced by pulse perfusion in compliant tubes (concomitant stretch). Unlike Akt, reactive oxygen species, activated nuclear factor kappaB, and suppression of H2O2-stimulated c-Jun-N-terminal kinase activity were similar in pulse-perfused compliant and stiff tubes. Thus, cyclic endothelial cell stretch by pulse perfusion enhances Akt-dependent antiapoptosis above that induced by steady or phasic shear stress and, unlike the latter, signals via a VEGF2R/caveolae-independent pathway. Enhancing this stretch pathway may prove useful for improving endothelial function in stiff arteries.