Bisphosphonate therapy associated with bilateral atypical femoral fracture and delayed union.

OBJECTIVES: The aim of this study was to identify the risk factors for developing atypical femoral fractures (AFF) and to examine the effect of bisphosphonate (BP) therapy on delayed bone union and bilateral fractures. PATIENTS AND METHODS: Between January 1st, 2012 and December 31st, 2020, a total of 74 AFF patients (8 males, 66 females; mean age: 75.4±7.2 years; range, 51 to 94 years) were recorded in two centers and retrospectively analyzed. A control fragility fracture group (n=143) was compared to the AFF group according to fracture characteristics, surgical fixation methods, comorbidities, and medications. The AFF patients were selected and subdivided according to their BP therapy: Group 1 (without BP) and Group 2 (with BP). Group 2 was further classified into Group 2a (<5 years of BP) and Group 2b (<5 years of BP). RESULTS: The multivariate logistic regression model showed that, BP drug use was the most significant risk factor in development of AFF (p<0.001, odds ratio= 10.749, 95% confidence interval: 3.886-29.733). The patients on BP showed longer bone union (Group 2 - 8.3±3.5 vs. Group 1 - 6.4±3.1 months, p=0.02; Group 2b - 9±3.8 vs. Group 2a - 7.3 ±3.9 months, p=0.09). Of all 19 cases of bilateral fractures, 14 were in Group 2 with BP use (p=0.11). Of 74 cases, 26 (35%) contralateral femoral X-rays were taken on admission and 24 (92%) showed AFF minor criteria signs. Of these 24 patients, 10 (42%) developed contralateral AFF. CONCLUSION: The most significant risk factor in development of AFF was BP drug use. Longer BP therapy (>5 years) showed longer delayed bone union, which was not significant. There was a relatively high risk of developing AFFs and bilateral fractures on BP therapy. In case of an AFF, a contralateral femoral X-ray must be always performed for signs of an impending fracture.

VIZSLA-Versatile Ice Zigzag Sublimation Setup for Laboratory Astrochemistry.

In this article, a new multi-functional high-vacuum astrophysical ice setup, VIZSLA (Versatile Ice Zigzag Sublimation Setup for Laboratory Astrochemistry), is introduced. The instrument allows for the investigation of astrophysical processes both in a low-temperature para-H2 matrix and in astrophysical analog ices. In the para-H2 matrix, the reaction of astrochemical molecules with H atoms and H+ ions can be studied effectively. For the investigation of astrophysical analog ices, the setup is equipped with various irradiation and particle sources: an electron gun for modeling cosmic rays, an H atom beam source, a microwave H atom lamp for generating H Lyman-α radiation, and a tunable (213-2800 nm) laser source. For analysis, an FT-IR (and a UV-visible) spectrometer and a quadrupole mass analyzer are available. The setup has two cryostats, offering novel features for analysis. Upon the so-called temperature-programmed desorption (TPD), the molecules, desorbing from the substrate of the first cryogenic head, can be mixed with Ar and can be deposited onto the substrate of the other cryogenic head. The efficiency of the redeposition was measured to be between 8% and 20% depending on the sample and the redeposition conditions. The well-resolved spectrum of the molecules isolated in an Ar matrix serves a unique opportunity to identify the desorbing products of a processed ice. Some examples are provided to show how the para-H2 matrix experiments and the TPD-matrix-isolation recondensation experiments can help understand astrophysically important chemical processes at low temperatures. It is also discussed how these experiments can complement the studies carried out by using similar astrophysical ice setups.

Atypical periprosthetic femoral fracture associated with long-term bisphosphonate therapy.

BACKGROUND: Atypical femoral fracture is one of the many complications after the long-term use of bisphosphonates. The American Society for Bone and Mineral Research has officially excluded periprosthetic femoral fractures (PFFs) from the definition of atypical femoral fractures (AFFs). Several case reports found that PFFs can occur with characteristics similar to those of AFFs. The purpose of our study was to evaluate the proportion of atypical fractures among Vancouver type B1 fractures, and to determine the association between the long-term use of bisphosphonates and the occurrence of atypical periprosthetic femoral fractures (APFFs). METHODS: In this retrospective study, we reviewed 41 patients with Vancouver type B1 periprosthetic fractures between January 1, 2011 and December 31, 2018. We classified them into two groups, namely atypical and typical PFFs, based on the fracture morphology. We noted the proportion of atypical periprosthetic fractures among B1 fractures and identified risk factors. RESULTS: Among the 41 PFFs, 5 (13%) fractures were classified as atypical PFF based on the radiological characteristics. The longer duration of bisphosphonate use was probably the only independent risk factor that significantly increases the occurrence of APFF (p = 0.03, 0.08 (CI 0.008 - 0.16)). There were no significant differences in age, gender, body mass index, comorbidities, corticosteroid use, positioning of the femoral stem, the method of fixation (cemented or cementless) and time lapse from before the primary prosthesis implantation to the PFF in the development of atypical fracture type. CONCLUSIONS: There seems to be a correlation between the long-term intake of bisphosphonates and the atypical periprosthetic fracture. Atypical femoral fracture can also occur in the periprosthetic form. TRIAL REGISTRATION: Study number: 22/2019-SZTE, http://www.klinikaikutatas.hu/hu/kutatasetika/jovahagyott-vizsgalatok-koezerdeku-adatai/category/25-jovahagyott-vizsgalatok-kozerdeku-adatai-rkeb-2019.html?download=985:22-2019 .

Selective conformational control by excitation of NH imino vibrational antennas.

An imino group was used for the first time as a vibrational antenna to manipulate molecular conformations. Imino-thiol isomers of thioacetamide were generated upon UV-irradiation of its amino-thione tautomer isolated in argon matrices at 11 K. Selective and reversible conformational isomerizations were induced by narrowband near-IR irradiation tuned at the frequencies of the 2ν(NH) first stretching overtone of each imino-thiol isomer. The conformational isomerization concerns the change in the orientation of a remote -SH group, while the orientation of the imino (C[double bond, length as m-dash]NH) group remains the same. Supported by quantum chemical anharmonic computations, this allowed for a reliable, isomer-selective vibrational assignment of the four imino-thiol isomers extending now over the full mid-IR and near-IR ranges. It was found that the experimental IR intensities of the 2ν(NH) first stretching overtones (computed 4-5 km mol-1) of the imino-thiol forms are comparable to those of the ν(NH) stretching fundamentals (computed 2-4 km mol-1). This is the first time such a phenomenon is reported for an imine molecule. The kinetics of conformational isomerization was monitored in situ, indicating that the irradiation-induced processes are significantly faster than the tunneling-driven spontaneous cis-trans rotamerization of the -SH group. Quantum yields for the rotamerizations of the -SH group resulting from the vibrational excitation of a remote -NH group were estimated and found to be comparable to those observed for matrix-isolated carboxylic acids and amino acids, where conformational changes of the -OH group were induced by the direct vibrational excitation of 2ν(OH) first stretching overtones.

[The prognostic value of the hip screw position in intertrochanteric fractures]. / A combfejcsavar helyzetének prognosztikai jelentosége a csípotáji törések esetén.

INTRODUCTION: In our study, we analyzed one of the Hungarian population's most frequent injuries, the hip fracture, focusing mainly on the lateral femoral neck and the pertrochanteric fractures. According to the classification of the Swiss Association for Ostheosynthesis (AO), we focused on 31-A1 and 31-A2 fractures, the incidence of which increases by ageing. METHOD: Between 2010 and 2016, we analyzed the data of 1179 patients. All of the fractures were stabilized with intramedullary nails. 992 patients received Stryker Gamma3®, whereas 187 patients' fractures were solved with Synthes PFNA® nail. In all cases, closed reduction method was used with fluoroscopy on an extension table. The surgeries were done in general or epidural anesthesia and performed by traumatology residents or specialists using standard lateral exploration. Data were collected using GEPACS software and statistical analysis was done with MS Excel. RESULTS: Cut-out occurred in 33 cases (2,79%): out of that 21 (1.78%) were left sided and 12 were (1,01%) right sided. 29 (87.87%) patients were treated with Gamma3 nail, and in 4 (12,12%) cases PFNA nail was used. The average TAD-index was 18 mm. CONCLUSION: According to recommendations of the TAD-index value, when using dynamic hip screw, it should be 20 mm or lower. The average index value was 18 mm which was equal in the complicated and non-complicated groups. Our study shows that the cut-out is independent from the TAD-index value, thus this recommendation cannot be applied for intramedullary nails. Orv Hetil. 2019; 160(9): 338-342.

[Drainage data analysis of chest-injured patients]. / Mellkasi sérültek drenázsadatainak vizsgálata.

INTRODUCTION: Chest injuries cause a significant number of pneumothorax (PTX) and hemothorax (HTX). The most commonly used treatment is chest-tube drainage. The position of the tube is a prime necessity to achieve adequate drainage. AIM: To analyze the duration of chest drainage at the occurrence of PTX and HTX. To find what the underlying cause of drainage insufficiency is and whether there is any relation between the surgical qualification needed to the procedure. METHOD: Clinical data of 110 injured patients from 2011 to 2015 were collected and retrospectively analyzed. In the case of tube breaking or drainage insufficiency it was investigated if repositioning, usage of new tubes or insertion of additional tubes resolved the drainage insufficiency. Authors investigated the location of the tube on x-ray and CT, and the connection between the drainage insufficiency and the surgical qualifications needed to the procedure. RESULTS: The average duration of chest drainage was 6.5 days. The duration of drainage was shorter by 1.9 days regarding the tube inserted in the middle section of the chest compared to the upper one and shorter by 1.2 days regarding the tube inserted in the lower section of the chest compared to the upper one. In the case of HTX, the duration of drainage was shorter by 2.8 days regarding the lower and by 3.6 days regarding the middle section compared to the upper position. Drainage insufficiency occurred in 30% of all cases. The duration of chest drainage was shorter after application of new tubes (9.5 days) than after reposition (10.2 days), but there was no significant difference. CONCLUSION: Chest injury is a wide entity, thus one standard protocol cannot be developed on the management of these injuries. Authors concluded that drainage duration decreases significantly if the position of the tube is in the middle or lower section of the chest. The high occurrence of drainage insufficiency was caused by inadequate tube positioning and tube breaking. The practical qualification of trauma surgeons did not play a significant role regarding the prevalence of drainage insufficiency rather if the tube positioning was appropriate. Orv Hetil. 2019; 160(5): 172-178.

Gas-phase structure and fragmentation pathways of singly protonated peptides with N-terminal arginine.

The gas-phase structures and fragmentation pathways of the singly protonated peptide arginylglycylaspartic acid (RGD) are investigated by means of collision-induced-dissociation (CID) and detailed molecular mechanics and density functional theory (DFT) calculations. It is demonstrated that despite the ionizing proton being strongly sequestered at the guanidine group, protonated RGD can easily be fragmented on charge directed fragmentation pathways. This is due to facile mobilization of the C-terminal or aspartic acid COOH protons thereby generating salt-bridge (SB) stabilized structures. These SB intermediates can directly fragment to generate b(2) ions or facilely rearrange to form anhydrides from which both b(2) and b(2)+H(2)O fragments can be formed. The salt-bridge stabilized and anhydride transition structures (TSs) necessary to form b(2) and b(2)+H(2)O are much lower in energy than their traditional charge solvated counterparts. These mechanisms provide compelling evidence of the role of SB and anhydride structures in protonated peptide fragmentation which complements and supports our recent findings for tryptic systems (Bythell, B. J.; Suhai, S.; Somogyi, A.; Paizs, B. J. Am. Chem. Soc. 2009, 131, 14057-14065.). In addition to these findings we also report on the mechanisms for the formation of the b(1) ion, neutral loss (H(2)O, NH(3), guanidine) fragment ions, and the d(3) ion.

Donor-acceptor properties of isonitriles studied by photoelectron spectroscopy and electron transmission spectroscopy.

Some alkyl and aryl isonitriles, considered as CO analogue sigma-donor and pi-acceptor ligands in transition metal chemistry, were studied by means of HeI photoelectron spectroscopy and electron transmission spectroscopy, in order to evaluate their donor-acceptor properties from the measured ionization energies (IE) and vertical electron attachment energies (VAE). The investigated molecules were 2-propyl, 1-butyl, tert-butyl, 1-pentyl, cyclohexyl, 2,6-dimethylphenyl, 4-methoxyphenyl and 4-chorophenyl isonitrile. By interpreting the spectra on the basis of literature data and quantum chemical calculations, the spectral features associated with the molecular orbitals mainly involved in coordination and back-donation were identified. The results show that the IE (10.62-10.95 eV) of the sigma electron pair (n(c)) responsible for the sigma-donor capability is substantially lower than that of CO. The VAEs of the empty pi* orbitals involved in the d/pi* back-donation indicate that aryl isonitriles are better acceptors (VAE <0.3 eV) than their aliphatic counterparts (VAE >2.7 eV). In the case of aryl derivatives, the pi-donor ability could also play some role in metal-ligand bonding (IE 8.74-9.34 eV). Isonitrile coordination characteristics are also compared with those of CO, N(2) and CH(3)CN.

Modeling of the gas-phase ion chemistry of protonated arginine.

Arginine is often involved at the C-terminus of peptides obtained from tryptic digests of proteins. The very basic guanidine group of the side-chain of arginine has a large effect on the backbone fragmentation of protonated peptides. Furthermore, arginine exhibits specific fragmentation reactions involving its side-chain. Various tautomerization states, conformers and side-chain dissociation channels of protonated arginine were studied using theoretical methods. The guanidine loss of protonated arginine is proved to be an S(N)2 substitution on the delta-carbon of the side-chain, starting from species containing the N(epsilon)H-C(+)(N(eta)H(2))(N(eta')H(2)) or -N(epsilon) (+)H(2)-C(N(eta)H)(N(eta')H(2)) moieties and leads to formation to either protonated guanidine or protonated proline. In the corresponding transition structures the proline moiety is protonated. Under low-energy collision conditions the extra proton transfers to the guanidine moiety, leading to the formation of C(+)(NH(2))(3). On the other hand, the lifetime of the fragmenting species under high-energy collision conditions is shorter, resulting in enhanced formation of protonated proline and its dissociation products. The first step of ammonia loss is the leaving of a preformed NH(3) from tautomers containing the -N(epsilon)H-C(N(eta)H(3) (+))(N(eta')H) or -N(epsilon)-C(N(eta)H(3) (+))(N(eta')H(2)) moieties. The resulting protonated carbodiimide group can be stabilized by intramolecular nucleophilic attack, leading to ring formation. Overall, reactions involved in the ammonia loss from protonated arginine can be considered as an S(N)1 substitution on the central zeta-carbon of the guanidine group.