Extreme Serum Titanium Concentration Induced by Acetabular Cup Failure: Unveiling a Unique Scenario of Titanium Alloy Debris Accumulation

The majority of contemporary total hip arthroplasty (THA) implants are constructed from Ti alloys, which are generally believed to generate fewer adverse local tissue reactions (ALTRs) compared to CoCr alloys. This study presents a case of unusual primary THA failure where a substantial release of Ti alloy debris was observed. A 52-year-old active male underwent THA after post-traumatic aseptic necrosis of the femoral head in 2006. Seventeen years after the procedure, the patient presented with groin pain and a restricted range of motion. X-rays revealed the protrusion of the alumina ceramic head through the Ti6Al4V acetabular cup. Trace element analysis indicated significantly elevated levels of serum Ti, Al, and V. CT and MRI confirmed Ti alloy cup failure and a severe ALTR. During revision surgery, it was found that the worn-out ceramic head was in direct contact with the acetabular cup, having protruded through a central hole it had created over time. No acetabular liner was found. Histological analysis of his tissue samples showed wear-induced synovitis with areas of multinucleated foreign body giant cells and the accumulation of numerous metal particles but no acute inflammatory response. Six months after the revision THA, the patient has experienced favourable outcomes. This case provides an instructive illustration for studying the consequences of the substantial release of Ti alloy debris from orthopedic implants.

Total Knee Replacement with an Uncemented Porous Tantalum Tibia Component: A Failure Analysis

Porous tantalum has been extensively used in orthopaedic surgery, including uncemented total knee arthroplasty (TKA). Favourable results were reported with earlier monobloc tibial components and the design evolved to modular implants. We aimed to analyse possible causes for extensive medial tibia bone loss, resulting in modular porous tantalum tibia baseplate fracture after primary TKA. Retrieved tissue samples were scanned with 3 MeV focused proton beam for Proton-Induced X-ray Emission (micro-PIXE) elemental analysis. Fractographic and microstructural analysis were performed by stereomicroscopy. A full 3D finite-element model was made for numerical analysis of stress-strain conditions of the tibial baseplate. Histological examination of tissue underneath the broken part of the tibial baseplate revealed dark-stained metal debris, which was confirmed by micro-PIXE to consist of tantalum and titanium. Fractographic analysis and tensile testing showed that the failure of the tibial baseplate fulfilled the criteria of a typical fatigue fracture. Microstructural analysis of the contact surface revealed signs of bone ingrowth in 22.5% of the surface only and was even less pronounced in the medial half of the tibial baseplate. Further studies are needed to confirm the responsibility of metal debris for an increased bone absorption leading to catastrophic tibial tray failure.

Electronic structure analysis of riboflavin: OVGF and EOM-CCSD study

The computational simulation of the photoelectron spectrum of active form of vitamin B2 is reported in the gas phase. In this work, we determine relative stability of eight riboflavin conformers by conformational search first with molecular mechanics AMMP potential in VEGA software at 553 K. Relative abundance of conformers was deduced from Boltzmann population weighting method (BPW). The three most stable conformers were then selected for computing valence, vertical ionization energies. We used high-level Equation-of-Motion Coupled-Cluster (EOM-IP-CCSD) method to obtain valence ionization energies (IP). In order to characterize the nature of ionization processes pertaining to different spectral bands, natural bonding orbital (NBO) method and molecular electrostatic potentials (MEP) were used to obtain orbital electron densities. The influence of the electronic structure of riboflavin on its biological activity is manifested via reduction of ionization energies of outermost orbitals which makes electron densities of these orbitals more readily available to participate in ligand-receptor bonding.

Epidemiology and pathogenesis of stroke in preterm infants: A systematic review

BACKGROUND:

Perinatal stroke is one of the principal causes of cerebral palsy (CP) in preterm infants. Stroke in preterm infants is different from stroke in term infants, given the differences in brain maturation and the mechanisms of injury exclusive to the immature brain. We conducted a systematic review to explore the epidemiology and pathogenesis of periventricular hemorrhagic infarction (PVHI), perinatal arterial ischemic stroke (PAIS) and cerebral sinovenous thrombosis (CSVT) in preterm infants.

METHODS:

Studies were identified based on predefined study criteria from MEDLINE, EMBASE, SCOPUS and WEB OF SCIENCE electronic databases from 2000 –2019. Results were combined using descriptive statistics.

RESULTS:

Fourteen studies encompassed 546 stroke cases in preterm infants between 23 –36 weeks gestational ages and birth weights between 450 –3500 grams. Eighty percent (436/546) of the stroke cases were PVHI, 17%(93/546) were PAIS and 3%(17/546) were CSVT. Parietal PVHI was more common than temporal and frontal lobe PVHI. For PAIS, left middle cerebral artery (MCA) was more common than right MCA or cerebellar stroke. For CSVT partial or complete thrombosis in the transverse sinus was universal. All cases included multiple possible risk factors, but the data were discordant precluding aggregation within a meta-analysis.

CONCLUSION:

This systematic review confirms paucity of data regarding the etiology and the precise causal pathway of stroke in preterm infants. Moreover, the preterm infants unlike the term infants do not typically present with seizures. Hence high index of clinical suspicion and routine cUS will assist in the timely diagnosis and understanding of stroke in this population.

An idea to explore: Visualization of ionization of amino acids using Mathematica

Ionization of amino acids (AA) is very important concept in biochemistry. We integrate the mathematical concept of probability with biochemically relevant process of AA ionization. We visualize the ionization process with Mathematica software discussing intramolecular interactions between weakly acidic/basic functional groups and charge-pH variation of amino acids in water solution. The visualizations rely on the notion of probability of ionization of functional groups and demonstrate how the extent of ionization and charge varies with pH of the solution. The examples described include amino acids and weak diprotic acids and bases. The aim is to help students better appreciate the importance and consequences of AA ionization and correct some misconceptions.

Vibrationally resolved valence and core photoionization and photoexcitation spectra of an electron-deficient trivalent boron compound: the case of catecholborane

Compounds containing trivalent boron (TB) as the electron-deficient site(s) find numerous practical uses ranging from Lewis bases in organic synthesis to high-tech industry, with a number of novel applications anticipated. We present an experimental and theoretical study of the gas-phase valence photoionization (VUV-PES), core photoionization (XPS) and photoexcitation (NEXAFS) spectra of a representative TB compound catecholborane (CB). For modelling and assigning the spectra we used the ΔDFT and restricted single excitation space TD-DFT methods for the XPS and NEXAFS, and OVGF and EOM-CCSD for the VUV-PES. The vibrationally resolved structure was computed in the Franck-Condon (FC) and Herzberg-Teller (FCHT) approximations generally resulting in a good agreement with the observed spectral features. For the prediction of core-electron binding energies (CEBEs) several density functionals were tested. The best performance overall was furnished by ωB97X-D suggesting that including the dispersion correction is beneficial. The FCHT vibronic intensities are in clear discrepancy with the B 1s NEXAFS spectrum if the harmonic approximation is used for the B-H wagging mode both in the ground and in the first core-excited state. Instead, a much better agreement is obtained if the excited state potential is approximated to a symmetric double-well. The observed vibronic pattern could be a general fingerprint of the presence of TB centre(s), specifically, the transfer of the (core) density to the vacant boron p-orbital in the excited state.

Polyetheretherketone (PEEK) cages for anterior column reconstruction in pyogenic vertebral osteomyelitis

The objective of study was to evaluate a case series of patients in whom polyetheretherketone (PEEK) cages were used for anterior column reconstruction in vertebral osteomyelitis. Fifteen patients underwent clinical and radiological evaluation with average follow-up of 26 months. Parameters assessed were time of surgery, blood loss, segmental kyphosis or lordosis angle, time to solid bony fusion, ambulatory status, and functional outcome. Mean time of surgery was 150 min with mean blood loss of 530 ml. One patient died in early postoperative period. All patients without preoperative neurologic deficit were walking unaided first day postoperatively. Solid bony fusion was demonstrated in 14 patients, on average 7.1 months postoperatively. Functional outcome at the latest follow-up was excellent, good, or fair in 86%. Two failures with recurrent infection were treated with PEEK cage removal and reinstrumentation. High success rate could be expected when PEEK cages are used for anterior column support in pyogenic vertebral osteomyelitis.

Best practice guidelines for communicating to parents the diagnosis of disability

Conveying a diagnosis of a disability to the parents of young children is difficult both for the parent and the clinician, however there is an ethical and medical imperative to do so. However, the process and manner of disclosure needs to be done well. When communication between parent and clinicians fails, parental mental health can be adversely affected. This paper adapts and explains how to use the SPIKES protocol to deliver "bad news" about a developmental disability diagnosis with families of infants <12-months old, using cerebral palsy as an example. Next, the range of responses parents experience to the delivery of bad news from "watchful waiting" to "acceptance" are outlined and explained. The knowledge needs of parents range from causes and prognosis to treatments and outcomes. Using clinical scenarios of recently diagnosed infants, commonly asked questions and suggested answers are tabled.

Electronic Structure of Biotin Conformers Studied with SAC-CI and OVGF Methods

In this work, the study was performed with 37 gas-phase conformers of biotin and two biologically active conformers of biotin in the ligand-receptor complexes with astavidin and streptavidin. The ionization energies and photoelectron spectra of conformers were calculated by two methods: the general-R symmetry-adapted cluster-configuration interaction (general-R-SAC-CI) method and the outer-valence Green's function (OVGF) method. The photoelectron spectrum of each conformer was calculated using basis set D95 (df,pd) for both methods. The simulated photoelectron spectra of free molecules and bioactive conformers calculated by the two methods were compared. Natural bonding orbital (NBO) calculations were also performed for the assignment of ionization bands of each conformer. NBO calculation indicated that the first to five ionization bands correspond to ionizations from orbitals localized in the two rings. The most important point about the ionization of all conformers is that the removal of an electron from the σ-bonding orbital (C-S) takes place above 10.0 eV.

Photoelectron spectra and biological activity of cinnamic acid derivatives revisited

The electronic structures of several derivatives of cinnamic acid have been studied by UV photoelectron spectroscopy (UPS) and Green's function quantum chemical calculations. The spectra reveal the presence of dimers in the gas phase for p-coumaric and ferulic acids. The electronic structure analysis has been related to the biological properties of these compounds through the analysis of some structure-activity relationships (SAR).

Characterisation of the electronic structure of galvinoxyl free radical by variable energy UPS, XPS and NEXAFS spectroscopy

UPS, XPS and NEXAFS spectra of persistent free radical galvinoxyl are assigned using theoretical ΔDFT and TDDFT methods.

Segmentation in cohesive systems constrained by elastic environments

The complexity of fracture-induced segmentation in elastically constrained cohesive (fragile) systems originates from the presence of competing interactions. The role of discreteness in such phenomena is of interest in a variety of fields, from hierarchical self-assembly to developmental morphogenesis. In this paper, we study the analytically solvable example of segmentation in a breakable mass-spring chain elastically linked to a deformable lattice structure. We explicitly construct the complete set of local minima of the energy in this prototypical problem and identify among them the states corresponding to the global energy minima. We show that, even in the continuum limit, the dependence of the segmentation topology on the stretching/pre-stress parameter in this problem takes the form of a devil's type staircase. The peculiar nature of this staircase, characterized by locking in rational microstructures, is of particular importance for biological applications, where its structure may serve as an explanation of the robustness of stress-driven segmentation.This article is part of the themed issue 'Patterning through instabilities in complex media: theory and applications.'

Funding for cerebral palsy research in Australia, 2000-2015: an observational study

OBJECTIVES

To examine the funding for cerebral palsy (CP) research in Australia, as compared with the National Institutes of Health (NIH).

DESIGN

Observational study.

SETTING

For Australia, philanthropic funding from Cerebral Palsy Alliance Research Foundation (CPARF) (2005-2015) was compared with National Health and Medical Research Council (NHMRC, 2000-2015) and Australian Research Council (ARC, 2004-2015) and CPARF and NHMRC funding were compared with NIH funding (USA).

PARTICIPANTS

Cerebral Palsy researchers funded by CPARF, NHMRC or NIH.

RESULTS

Over 10 years, total CPARF philanthropic funding was $21.9 million, including people, infrastructure, strategic and project support. As competitive grants, CPARF funded $11.1 million, NHMRC funded $53.5 million and Australian Research Council funded $1.5 million. CPARF, NHMRC and NIH funding has increased in real terms, but only the NIH statistically significantly increased in real terms (mean annual increase US$4.9 million per year, 95% CI 3.6 to 6.2, p<0.001). The NHMRC budget allocated to CP research remained steady over time at 0.5%. A network analysis indicated the relatively small number of CP researchers in Australia is mostly connected through CPARF or NHMRC funding.

CONCLUSIONS

Funding for CP research from the Australian government schemes has stabilised and CP researchers rely on philanthropic funding to fill this gap. In comparison, the NIH is funding a larger number of CP researchers and their funding pattern is consistently increasing.

In silico analysis of the transportome in human pancreatic ductal adenocarcinoma

The altered expression and/or activity of ion channels and transporters (transportome) have been associated with malignant behavior of cancer cells and were proposed to be a hallmark of cancer. However, the impact of altered transportome in epithelial cancers, such as pancreatic ductal adenocarcinoma (PDAC), as well as its pathophysiological consequences, still remains unclear. Here, we report the in silico analysis of 840 transportome genes in PDAC patients' tissues. Our study was focused on the transportome changes and their correlation with functional and behavioral responses in PDAC tumor and stromal compartments. The dysregulated gene expression datasets were filtered using a cut-off of fold-change values ≤-2 or ≥2 (adjusted p value ≤0.05). The dysregulated transportome genes were clearly associated with impaired physiological secretory mechanisms and/or pH regulation, control of cell volume, and cell polarity. Additionally, some down-regulated transportome genes were found to be closely linked to epithelial cell differentiation. Furthermore, the observed decrease in genes coding for calcium and chloride transport might be a mechanism for evasion of apoptosis. In conclusion, the current work provides a comprehensive overview of the altered transportome expression and its association with predicted PDAC malignancy with special focus on the epithelial compartment.

A systematic review of upper extremity casting for children and adults with central nervous system motor disorders

Objective: To summarize evidence on the use of upper extremity casting designed to achieve reductions in contracture, tone, pain, function, oedema or spasticity in the elbow, wrist or hand of adults and children with neurological conditions.

Data sources: A search was conducted of the Cochrane Database of Systematic Reviews; the electronic databases MEDLINE, EMBASE, CINAHL, PEDro, OT-Seeker; Google Scholar; reference lists of retrieved trial reports and review articles.

Review methods: Two independent reviewers determined whether retrieved study abstracts met inclusion criteria: human subjects; >50% of participants children or adults described as having brain injury, cerebral palsy or stroke. Methodological quality of randomized controlled trials was rated using the PEDro scale (1—10 highest).

Results: Thirty-one papers were retrieved and 23 studies appraised: three were randomized controlled trials and four were systematic reviews. Over three-quarters of the studies, excluding systematic reviews, were lower level evidence (n = 4 level V; n = 4 level IV; n = 1 level III). Methodological quality of randomized controlled trials was high (PEDro 8, 8 and 9) and there were modest positive short-term outcomes for two trials, although they did not include no-stretch comparison conditions. Safety issues typically included pain or skin breakdown; two adverse events were not cast related.

Conclusion: While theoretical rationales suggest upper limb casting should be effective there is insufficient high-quality evidence regarding impact or long-term effects to either support or abandon this practice. High variability in casting protocols indicates little consistency or consensus in practice. As maximum or low-load stretch are rationales for cast application, the absence of no-stretch conditions in existing trials is a major weakness in current evidence.

Electronic structure of antibiotic erythromycin

The electronic structure of erythromycin A (ERYMA) molecule has been studied by UV photoelectron spectroscopy and assigned (in the low ionization energy region only) by empirical arguments. The two orbitals with highest energy (lowest ionization energy) are localized on the nitrogen of the desosamine sugar functional group and on the ester group of macrolide (lactone) ring. We discuss how these orbital energies can help to rationalize the known mode of binding of ERYMA to their biological receptors.

The study of the electronic structure of some N-heterocyclic carbenes (NHCs) by variable energy photoelectron spectroscopy

UV and X-ray photoelectron spectra of three N-heterocyclic carbenes under synchrotron radiation reveal details of their electronic structure and are used as a benchmark to test computational methods for treating core ionizations in systems with unusual electronic structures.

The Gibbs free energy of formation of halogenated benzenes, benzoates and phenols and their potential role as electron acceptors in anaerobic environments

The sequence of redox reactions in the natural environment generally follows the electron affinity of the electron acceptors present and can be rationalized by the redox potentials of the appropriate half-reactions. Answering the question how halogenated aromatics fit into this sequence requires information on their Gibbs free energy of formation values. In 1992 Gibbs free energy data for various classes of halogenated aromatic compounds were systematically explored for the first time based on Benson’s group contribution method. Since then more accurate quantum chemical calculation methods have become available. Here we use these methods to estimate enthalpy and Gibbs free energy of formation values of all chlorinated and brominated phenols. These data and similar state-of-the-art datasets for halogenated benzenes and benzoates were then used to calculate two-electron redox potentials of halogenated aromatics for standard conditions and for pH 7. The results underline the need to take speciation into consideration when evaluating redox potentials at pH 7 and highlight the fact that halogenated aromatics are excellent electron acceptors in aqueous environments.

ANO1 (TMEM16A) in pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) has one of the worst survival rates of all cancers. ANO1 (TMEM16A) is a recently identified Ca²⁺-activated Cl⁻ channel (CaCC) that is upregulated in several tumors. Although ANO1 was subject to extensive studies in the recent years, its pathophysiological function has only been poorly understood. The aim of the present study is to establish the significance of ANO1 in PDAC behavior and demarcate its roles in PDAC from those of the volume-regulated anion channel (VRAC). We performed qPCR and Western blot measurements on different PDAC cell lines (Panc-1, Mia PaCa 2, Capan-1, AsPC-1, BxPC-3) and compared the results to those obtained in a human pancreatic ductal epithelium (HPDE) cell line. All cancer cell lines showed an upregulation of ANO1 on mRNA and protein levels. Whole-cell patch-clamp recordings identified large Ca²⁺ and voltage-dependent Cl⁻ currents in PDAC cells. Using siRNA knockdown of ANO1 and three ANO1 inhibitors (T16A_inh-A01, CaCC_inh-A01, and NS3728), we found that ANO1 is the main constituent of CaCC current in PDAC cells. We further characterized these three inhibitors and found that they had unspecific effects on the free intracellular calcium concentration. Functional studies on PDAC behavior showed that surprisingly inhibition of ANO1 did not influence cellular proliferation. On the other hand, we found ANO1 channel to be pivotal in PDAC cell migration as assessed in wound healing experiments.

Photoelectron Spectroscopy of Heterocycles. Phenyloxiranes

The Hel photoelectron spectra of 2-phenyloxirane, 2,2-diphenyloxirane, trans-2.3-diphenyloxirane, 2,2,3-triphenyloxirane, and 2,2,3,3-tetraphenyloxirane are reported. Comparison with the spectra of ethylene oxide (oxirane), benzene, and the following phenylethenes-styrene (1). I,1-diphenylethene (2), cis-stilbene (3), trans-stilbene (4), triphenylethene (5), and tetraphenylethene (6) - allowed to assign the lower ionization energies of the phenyloxiranes. Splitting of the lowest energy benzene π-orbitals is qualitatively the same in both classes of compounds. Because of the perpendicular orientation of the oxygen lone-pair in comparison to the π-electrons of the ethylene double bond this splitting is considerably smaller in phenyloxiranes.

Photoelectron Spectroscopy of Heterocycles 1-(Diazinyl)-2-(Pyridyl)-ethenes (Triazastilbenes)

The photoelectron (PE) spectra of 1-(4-pyrimidyl)-2-(3-pyridyl)-ethene 1, 1-(2-pyrimidyl)-2- (3-pyridyl)-ethene 2, 1-(4-pyridazinyl)-2-(3-pyridyl)-ethene 3, 1-(3-pyridazinyl)-2-(3-pyridyl)- ethene 4 and 1-(2-pyrazinyl)-2-(3-pyridyl)-ethene 5 all in their trans conformations have been recorded using Hel radiation. Comparisons with the PE spectra of styrylpyridines, dipyridylethenes and diazabenzenes allowed the assignment of all ionization energies, Ei, corresponding to π- and nitrogen lone pair ionizations in the region of Ei < 12 eV. The variations in PE spectra of five isomeric triazastilbenes studied are due to different nitrogen atom positions in the diazinyl ring.

Das Photoelektronenspektrum von Pyridin-N-Oxid anhand von Hel/Hell- Intensitäten [1] / Assignment of the Pyridine-N-oxide Photoelectron Spectrum on the Basis of Hel/Hell Intensities [1]

Comparison of Hel and Hell photoelectron (PE) spectra of pyridine-N-oxide enables the completion of the assignment of its electronic structure

Photoelectron Spectroscopy of Heterocycles. Polypyridines

The photoelectron (PE) spectra of 2,2′-bipyridine 1, 2,2′:6′,2″-terpyridine 2, and 2,2′,2″,2‴-tetrapyridine 3 have been measured using He I radiation. For 1-3 standard SCF LCAO MO calculations wer also performed. Comparison of PE spectra and these calculations allowed the assignment of π-ionizations and indirectly also the nitrogen lone pair ionizations in 1-3. Factors influencing the conformations of 1-3 in the gas phase are also mentioned.

Notiz: Quantification of Symmetry

A new mathematical criterion is suggested for symmetry ranking, i.e. determination of an “absolute symmetry scale” for discrete, finite groups. The criterion is based on both, the periods (orders) of each group element and the order of the group itself. This is different from the current criteria which consider only the orders of the groups themselves. The symmetry ranking, based on the new criterion, is applied to the symmetry point groups.

Role of vesicular nucleotide transporter VNUT (SLC17A9) in release of ATP from AR42J cells and mouse pancreatic acinar cells

ATP is released from cells in response to various stimuli. Our previous studies on pancreas indicated that pancreatic acini could be major stores of secreted ATP. In the present study, our aim was to establish the role of the vesicular nucleotide transporter (VNUT), SLC17A9, in storage and release of ATP. Freshly prepared acini from mice and AR42J rat acinar cells were used in this study. We illustrate that in AR42J cells, quinacrine (an ATP store marker) and Bodipy ATP (a fluorescent ATP analog) co-localized with VNUT-mCherry to vesicles/granules. Furthermore, in acini and AR42J cells, a marker of the zymogen granule membranes, Rab3D, and VNUT co-localized. Dexamethasone treatment of AR42J cells promoted formation of acinar structures, paralleled by increased amylase and VNUT expression, and increased ATP release in response to cholinergic stimulation. Mechanical stimulus (pressure) and cell swelling also induced ATP release, but this was not influenced by dexamethasone, most likely indicating different non-zymogen-related release mechanism. In conclusion, we propose that VNUT-dependent ATP release pathway is associated with agonist-induced secretion process and downstream purinergic signalling in pancreatic ducts.

Characterisation of the electronic structure of some stable nitroxyl radicals using variable energy photoelectron spectroscopy

Core and valence ionizations of three stable nitroxyl radicals studied using synchrotron radiation reveal strong intramolecular interactions in amide derivatives.