Experiments and Modeling on the Stain-Controlled Time- and Temperature-Dependent Cyclic Ratchetting Plasticity of the Nickel-Based Superalloy IN100

In this paper, the time- and temperature-dependent cyclic ratchetting plasticity of the nickel-based alloy IN100 is experimentally investigated in strain-controlled experiments in the temperature range from 300 °C to 1050 °C. To this end, uniaxial material tests are performed with complex loading histories designed to activate phenomena as strain rate dependency, stress relaxation as well as the Bauschinger effect, cyclic hardening and softening, ratchetting and recovery from hardening. Plasticity models with different levels of complexity are presented that consider these phenomena, and a strategy is derived to determine the multitude of temperature-dependent material properties of the models in a step-by-step procedure based on sub-sets of experimental data of isothermal experiments. The models and the material properties are validated based on the results of non-isothermal experiments. A good description of the time- and temperature-dependent cyclic ratchetting plasticity of IN100 is obtained for isothermal as well as non-isothermal loading with models including ratchetting terms in the kinematic hardening law and the material properties obtained with the proposed strategy.

A flexion osteotomy for correction of a distal tibial recurvatum deformity

Aims

There is little information about how to manage patients with a recurvatum deformity of the distal tibia and osteoarthritis (OA) of the ankle. The aim of this study was to evaluate the functional and radiological outcome of addressing this deformity using a flexion osteotomy and to assess the progression of OA after this procedure.

Patients and Methods

A total of 39 patients (12 women, 27 men; mean age 47 years (28 to 72)) with a distal tibial recurvatum deformity were treated with a flexion osteotomy, between 2010 and 2015. Nine patients (23%) subsequently required conversion to either a total ankle arthroplasty (seven) or an arthrodesis (two) after a mean of 21 months (9 to 36). A total of 30 patients (77%), with a mean follow-up of 30 months (24 to 76), remained for further evaluation. Functional outcome, sagittal ankle joint OA using a modified Kellgren and Lawrence Score, tibial lateral surface (TLS) angle, and talar offset ratio (TOR) were evaluated on pre- and postoperative weight-bearing radiographs.

Results

Postoperatively, the mean score for pain, using a visual analogue scale, decreased significantly from 4.3 to 2.5 points and the mean American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score improved significantly from 59 to 75 points (both p < 0.001). The mean TLS angle increased significantly by 6.6°; the mean TOR decreased significantly by 0.24 (p < 0.001). Radiological evaluation showed an improvement or no progression of sagittal ankle joint OA in 32 ankles (82%), while seven ankles (18%) showed further progression.

Conclusion

A flexion osteotomy effectively improved the congruency of the ankle joint. In 30 patients (77%), the joint could be saved, whereas in nine patients (23%), the treatment delayed a joint-sacrificing procedure. Cite this article: Bone Joint J 2019;101-B:682–690.

Arthroscopically assisted fixation of Hawkins type II talar neck fractures: a case series

Aims

Arthroscopically controlled fracture reduction in combination with percutaneous screw fixation may be an alternative approach to open surgery to treat talar neck fractures. The purpose of this study was thus to present preliminary results on arthroscopically reduced talar neck fractures.

Patients and Methods

A total of seven consecutive patients (four women and three men, mean age 39 years (19 to 61)) underwent attempted surgical treatment of a closed Hawkins type II talar neck fracture using arthroscopically assisted reduction and percutaneous screw fixation. Functional and radiological outcome were assessed using plain radiographs, as well as weight-bearing and non-weight-bearing CT scans as tolerated. Patient satisfaction and pain sensation were also recorded.

Results

Primary reduction was obtained arthroscopically in all but one patient, for whom an interposed fracture fragment had to be removed through a small arthrotomy to permit anatomical reduction. The quality of arthroscopic reduction and restoration of the talar geometry was excellent in the remaining six patients. There were no signs of talar avascular necrosis or subtalar degeneration in any of the patients. In the whole series, the functional outcome was excellent in five patients but restricted ankle movement was observed in two patients. All patients had a reduction in subtalar movement. At final follow-up, all patients were satisfied and all but one patient were pain free.

Conclusion

Arthroscopically assisted reduction and fixation of talar neck fractures was found to be a feasible treatment option and allowed early functional rehabilitation. Cite this article: Bone Joint J 2018;100-B:461-7.

Custom-made total ankle arthroplasty for the salvage of major talar bone loss

Aims

A failed total ankle arthroplasty (TAA) is often associated with much bone loss. As an alternative to arthrodesis, the surgeon may consider a custom-made talar component to compensate for the bone loss. Our aim in this study was to assess the functional and radiological outcome after the use of such a component at mid- to long-term follow-up.

Patients and Methods

A total of 12 patients (five women and seven men, mean age 53 years; 36 to77) with a failed TAA and a large talar defect underwent a revision procedure using a custom-made talar component. The design of the custom-made components was based on CT scans and standard radiographs, when compared with the contralateral ankle. After the anterior talocalcaneal joint was fused, the talar component was introduced and fixed to the body of the calcaneum.

Results

At a mean follow-up of 6.9 years (1 to 13), 11 ankles were stable with no radiological evidence of loosening. Only one was lost to follow-up. The mean arc of movement was 21° (10° to 35°). A total of nine patients (75%) were satisfied or very satisfied with the outcome, two (17%) were satisfied but with reservations and one (8%) was not satisfied. All but one patient had an improvement in the American Orthopaedic Foot and Ankle Society hindfoot score (p = 0.01). Just one patient developed deep infection, leading to arthrodesis.

Conclusion

A custom-made talar component yielded satisfactory results with regard to function, stability and satisfaction. This should encourage the use of such components as an alternative to arthrodesis of the ankle in patients with a failed TAA. Cite this article: Bone Joint J 2017;99-B:231–6.

Spin Pumping and Measurement of Spin Currents in Optical Superlattices

We report on the experimental implementation of a spin pump with ultracold bosonic atoms in an optical superlattice. In the limit of isolated double wells, it represents a 1D dynamical version of the quantum spin Hall effect. Starting from an antiferromagnetically ordered spin chain, we periodically vary the underlying spin-dependent Hamiltonian and observe a spin current without charge transport. We demonstrate a novel detection method to measure spin currents in optical lattices via superexchange oscillations emerging after a projection onto static double wells. Furthermore, we directly verify spin transport through in situ measurements of the spins' center-of-mass displacement.

[Ultrasound appearance of the area of uterine closure in asymptomatic patients at 48 hours of uneventful cesarean section]

OBJECTIVE

It seeks to assess the appearance of the hysterorrhaphy area and seeks hematoma in asymptomatic patients at 48hours of their cesarean.

METHOD

It is common to see, ultrasound or CT scan, collection of images next to the hysterorrhaphy area in symptomatic patients after cesarean. Their interpretation remains difficult which led us to propose a prospective study looking for an evocative image collection or hematoma in asymptomatic patients at 48hours of their cesarean. It was directed suprapubic and transvaginal pelvic ultrasound with study area hysterorrhaphy and inter-uterine bladder space.

RESULTS

The suprapubic ultrasound examination was performed in 31 asymptomatic patients after collecting their written consent. Twenty-eight patients also received an endovaginal examination. The studied area was easily identified by visualizing the path of hysterotomy and hyperechoic aspect of the hysterorrhaphy. In 28 cases there were no abnormal image in front of the hysterorrhaphy area. In 3 cases, an evocative image of a haematic collection was displayed and measured a maximum of only 49mm long axis with a weak Doppler signal. The exam was very well tolerated by patients, especially by transvaginal route. Also the duration of ultrasound never exceeded 58seconds and remained fastest vaginally.

CONCLUSION

This preliminary work to a prospective double cohort (symptomatic patients and asymptomatic patients) has clarified the technique to use and focus in the search for a collection next to the hysterorrhaphy area. Ultrasound examination postoperatively, especially vaginally, is very fast, well tolerated with satisfactory image quality. Finally in this cohort of asymptomatic patients, it was very unusual for a collection, confirming the credit to be given to this type of image in case of symptoms after cesarean.

Treatment of extended osteochondral lesions of the talus with a free vascularised bone graft from the medial condyle of the femur

Large osteochondral lesions (OCLs) of the shoulder of the talus cannot always be treated by traditional osteochondral autograft techniques because of their size, articular geometry and loss of an articular buttress. We hypothesised that they could be treated by transplantation of a vascularised corticoperiosteal graft from the ipsilateral medial femoral condyle. Between 2004 and 2011, we carried out a prospective study of a consecutive series of 14 patients (five women, nine men; mean age 34.8 years, 20 to 54) who were treated for an OCL with a vascularised bone graft. Clinical outcome was assessed using a visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. Radiological follow-up used plain radiographs and CT scans to assess graft incorporation and joint deterioration. At a mean follow-up of 4.1 years (2 to 7), the mean VAS for pain had decreased from 5.8 (5 to 8) to 1.8 (0 to 4) (p = 0.001) and the mean AOFAS hindfoot score had increased from 65 (41 to 70) to 81 (54 to 92) (p = 0.003). Radiologically, the talar contour had been successfully reconstructed with stable incorporation of the vascularised corticoperiosteal graft in all patients. Joint degeneration was only seen in one ankle. Treatment of a large OCL of the shoulder of the talus with a vascularised corticoperiosteal graft taken from the medial condyle of the femur was found to be a safe, reliable method of restoring the contour of the talus in the early to mid-term.

Profiling of steroid metabolites after transdermal and oral administration of testosterone by ultra-high pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

The screening of testosterone (T) misuse for doping control is based on the urinary steroid profile, including T, its precursors and metabolites. Modifications of individual levels and ratio between those metabolites are indicators of T misuse. In the context of screening analysis, the most discriminant criterion known to date is based on the T glucuronide (TG) to epitestosterone glucuronide (EG) ratio (TG/EG). Following the World Anti-Doping Agency (WADA) recommendations, there is suspicion of T misuse when the ratio reaches 4 or beyond. While this marker remains very sensitive and specific, it suffers from large inter-individual variability, with important influence of enzyme polymorphisms. Moreover, use of low dose or topical administration forms makes the screening of endogenous steroids difficult while the detection window no longer suits the doping habit. As reference limits are estimated on the basis of population studies, which encompass inter-individual and inter-ethnic variability, new strategies including individual threshold monitoring and alternative biomarkers were proposed to detect T misuse. The purpose of this study was to evaluate the potential of ultra-high pressure liquid chromatography (UHPLC) coupled with a new generation high resolution quadrupole time-of-flight mass spectrometer (QTOF-MS) to investigate the steroid metabolism after transdermal and oral T administration. An approach was developed to quantify 12 targeted urinary steroids as direct glucuro- and sulfo-conjugated metabolites, allowing the conservation of the phase II metabolism information, reflecting genetic and environmental influences. The UHPLC-QTOF-MS(E) platform was applied to clinical study samples from 19 healthy male volunteers, having different genotypes for the UGT2B17 enzyme responsible for the glucuroconjugation of T. Based on reference population ranges, none of the traditional markers of T misuse could detect doping after topical administration of T, while the detection window was short after oral TU ingestion. The detection ability of the 12 targeted steroids was thus evaluated by using individual thresholds following both transdermal and oral administration. Other relevant biomarkers and minor metabolites were studied for complementary information to the steroid profile, including sulfoconjugated analytes and hydroxy forms of glucuroconjugated metabolites. While sulfoconjugated steroids may provide helpful screening information for individuals with homozygotous UGT2B17 deletion, hydroxy-glucuroconjugated analytes could enhance the detection window of oral T undecanoate (TU) doping.

Pre- and post-synaptic mechanisms regulating the clustering of type A gamma-aminobutyric acid receptors (GABAA receptors)

Postsynaptic clustering of GABAA (type A gamma-aminobutyric acid) receptors is essential to ensure proper function of GABAergic synapses. This process is initiated during synapse formation and is maintained throughout life. The tubulin-associated protein gephyrin is required for clustering of GABAA receptors, but its specific role in this process is not understood. A second protein associated selectively with GABAA receptors at postsynaptic sites is dystrophin. It is present in a subset of GABAergic synapses along with several partners, forming the dystrophin-associated protein complex. In this review, we discuss recent advances in the role of neuronal activity and trans-synaptic signaling for the clustering of gephyrin and dystrophin during synaptogenesis and on the role of these proteins for plasticity and maintenance of mature synapses.

Method for confirmation of synthetic corticosteroids in doping urine samples by liquid chromatography-electrospray ionisation mass spectrometry

In this study, we report on the development of a method to confirm simultaneously nine of the most commonly abused synthetic corticosteroids in urine based on liquid chromatography-electrospray ionisation mass spectrometry. A considerable simplified sample preparation procedure, including liquid-liquid phase extraction with Extrelut-NT3 columns, provided both excellent sample purification and high overall recoveries. Complete HPLC separations were obtained on a reversed-phase column with 1 mM ammonium acetate-acetonitrile (60:40, v/v) as mobile phase. Mass spectral acquisition was done in the negative ion, and selected ion monitoring modes to identify the drugs with at least three characteristic ions. Detection limits were determined at < or =1 ng/ml and the confirmation limits at 1 to 5 ng/ml.

Test methods: anabolics

In the International Olympic Committee (IOC) accredited laboratories, specific methods have been developed to detect anabolic steroids in athletes' urine. The technique of choice to achieve this is gas-chromatography coupled with mass spectrometry (GC-MS). In order to improve the efficiency of anti-doping programmes, the laboratories have defined new analytical strategies. The final sensitivity of the analytical procedure can be improved by choosing new technologies for use in detection, such as tandem mass spectrometry (MS-MS) or high resolution mass spectrometry (HRMS). A better sample preparation using immuno-affinity chromatography (IAC) is also a good tool for improving sensitivity. These techniques are suitable for the detection of synthetic anabolic steroids whose structure is not found naturally in the human body. The more and more evident use, on a large scale, of substances chemically similar to the endogenous steroids obliges both the laboratory and the sports authorities to use the steroid profile of the athlete in comparison with reference ranges from a population or with intraindividual reference values.

The N-terminal domain of gamma-aminobutyric Acid(B) receptors is sufficient to specify agonist and antagonist binding

The recently identified gamma-aminobutyric acid type B receptors (GABA(B)Rs) share low sequence similarity with the metabotropic glutamate (mGlu) receptors. Like the mGlu receptors, the N-terminal extracellular domain (NTED) of GABA(B)Rs is proposed to be related to bacterial periplasmic binding proteins (PBPs). However, in contrast to the mGlu receptors, the GABA(B)Rs lack a cysteine-rich region that links the PBP-like domain to the first transmembrane domain. This cysteine-rich region is necessary for the PBP-like domain of mGlu receptors to bind glutamate. To delimit the ligand-binding domain of GABA(B)Rs, we constructed a series of chimeric GABA(B)R1/mGluR1 and truncated GABA(B)R1 receptor mutants. We provide evidence that despite the lack of a cysteine-rich region, the NTED of GABA(B)Rs contains all of the structural information that is necessary and sufficient for ligand binding. Moreover, a soluble protein corresponding to the NTED of GABA(B)Rs reproduces the binding pharmacology of wild-type receptors. This demonstrates that the ligand-binding domain of the GABA(B)Rs can correctly fold when dissociated from the transmembrane domains.

Detection of human growth hormone doping in urine: out of competition tests are necessary

The misuse of human growth hormone (hGH) in sport is deemed to be unethical and dangerous because of various adverse effects. Thus, it has been added to the International Olympic Committee list of banned substances. Until now, the very low concentration of hGH in the urine made its measurement difficult using classical methodology. Indeed, for routine diagnosis, only plasma measurements were available. However, unlike blood samples, urine is generally provided in abundant quantities and is, at present, the only body fluid allowed to be analysed in sport doping controls. A recently developed enzyme-linked immunosorbent assay (Norditest) makes it now possible, without any extraction, to measure urinary hGH (u-hGH) in a dynamic range of 2-50 ng hGH/l. In our protocol, untreated and treated non-athlete volunteers were followed. Some of them received therapeutical doses of recombinant hGH (Norditropin) for one week either intramuscularly (three increasing doses) or subcutaneously (12 i.u. every day). The u-hGH excretion after treatment showed dramatic increases of 50-100 times the basal values and returned to almost the mean normal level after 24 h. u-hGH was also measured in samples provided by the anti-doping controls at major and minor competitions. Depending on the type of efforts made during the competition, the hGH concentration in urine was dramatically increased. Insulin-like growth factor binding proteins and beta 2-microglobulins in urine and/or in blood could be necessary for the correct investigation of any hGH doping test procedure.

Pharmacokinetics and pharmacodynamics of benazepril hydrochloride in patients with major proteinuria

We have investigated whether the pharmacokinetics and pharmacodynamics of the ACE inhibitor benazepril hydrochloride are altered with proteinuria by studying 8 patients with major proteinuria of different causes who were given a single dose of 10 mg p.o. The maximum plasma concentration of benazepril was found between 0.5 and 2 h after dosing (median 1 h). Its elimination was almost complete within 6 h. Peak plasma levels of benazeprilat, the active metabolite of benazepril, were observed between 1 and 6 h (median 2.5 h). The elimination of benazeprilat from plasma was biphasic, with mean initial and terminal half-lives of 3.0 and 17.3 h, respectively. On average, the pharmacokinetic parameters of benazepril and benazeprilat in the patients did not differ from those in a historical control group of healthy volunteers, but intersubject variability in the AUC and half-lives of benazeprilat was greater in the patients. Plasma ACE was completely inhibited from 1.5 to 6 h after dosing, and at 48 h the mean inhibition was still 42%. Plasma renin showed substantial intersubject variation. Mean supine blood pressure (systolic/diastolic) was reduced from baseline by a maximum of 18/13 mm Hg at 6 h. Proteinuria was diminished after benazepril in 7 patients. In conclusion, the results of this study suggest that proteinuria in the nephrotic range does not require a change in benazepril dosage.

[Inversion 8 and consecutive trisomy of region 8q22----qter]

A girl with severe mental retardation and conspicuous phenotype features is described. The chromosomal aberration consists of a partial trisomy 8q of the region 8q22----qter. Minor deletion of the terminal part of the region 8p23 must be presumed, resulting in partial monosomy of this region. Inversion of chromosome 8 was found in the father and his mother.

Assessment of vibration induced white finger: reliability and validity of two tests

The reliability and validity of two tests (cold water and reactive hyperaemia) designed to confirm a patient's history of vibration induced white finger were studied. The cold water test is a measure of digital rewarming after hand immersion in cold water. Reactive hyperaemia consists of measuring digital rewarming after cold water immersion plus temporary ischaemia imposed on the hand. For ten weeks, ten healthy male volunteers were submitted once a week to both tests to study their reliability. The results showed a strong inter and intraindividual scattering. The mean value for the whole group, however, did not differ significantly from one week to the next. Fifty two subjects exposed to hand/arm vibration were submitted to both tests to estimate their validity. They were classified, according to their medical history, into three groups: A = no symptoms, B = tingling or numbess, or both, C = Raynaud's phenomenon. Both tests agreed with the clinical staging. For reactive hyperaemia, however, the differences between the groups were statistically significant only when the test was performed at 10 degrees C. These tests are more useful to study a group than an individual case. Time has no significant effect on the mean result of a group.

Valproic acid in childhood epilepsy: anticonvulsive efficacy in relation to its plasma levels

Plasma levels of valproic acid were monitored for two years in 90 epileptic children. From 34 patients receiving sodium valproate as monotherapy, complete seizure control could be achieved in 28 children (82%) with a mean (+/- SD) plasma level of 65.1 +/- 20.3 micrograms/ml. In 6 patients (18%) seizures recurred. Since their plasma levels were significantly (p = 0.008) higher (91.7 +/- 35.2 micrograms/ml) than in the controlled patients, their disorder might be regraded as resistant to therapy with sodium valproate. The drug seems to be effective in patients with absences, tonic-clonic seizures and partial epilepsy. The most common combination of anticonvulsants administered was valproate/phenobarbital (n = 22). In 14 children of this group (64%) seizures were completely controlled with plasma levels of 54.6 +/- 26.5 micrograms/ml. In the 5 uncontrolled patients (23%) valproate concentrations were lower (33.8 +/- 28.2 micrograms/ml; p = 0.08). 20 children were treated with more than two anticonvulsants. This population probably represents the most severe cases. Therefore it was not surprising that only 7 patients (35%) exhibited complete seizure control with valproate plasma concentrations of 63.1 +/- 51.9 micrograms/ml. In the uncontrolled patients these levels were slightly lower (43.8 +/- 24.8 micrograms/ml). Side effects were observed in 7 patients (21%) receiving sodium valproate alone. Most common effects were increase in appetite (n = 4), and gastrointestinal disturbances (n = 2). Additionally, one patient complained about transient hair loss and one felt tired. In most cases their plasma concentrations were above 70 micrograms/ml. A therapeutic range of 40--90 micrograms/ml is postulated.