Inhibition in the somatosensory system: An integrative neuropharmacological and neuroimaging approach

The presented study investigates the functional role of GABA in somatosensory processing, using a combined neuropharmacological-neuroimaging approach. Three different GABA agonists (GABA_A: alprazolam, ethanol; GABA_B: baclofen) were investigated in a double blind cross-over design in 16 male participants, accomplishing a tactile perception task. Somatosensory evoked magnetic fields modulated by GABAR-agonists and placebo were recorded using whole-head magnetoencephalography. Peak latencies and amplitudes of primary (SI) and secondary (SII) somatosensory cortex source activities confirmed the previously reported role of GABA as a modulator of somatosensory processing. Significant inhibitory effects on the latency of SII and on the amplitude of SI and SII were found exclusively for alprazolam, a positive allosteric modulator at GABA_A receptors. The GABA_B agonist baclofen did not have any modulatory effect. Moreover, we investigated whether the observed effects of alprazolam on the level of SII were explainable by the mere propagation of activity from SI to SII modulated by GABA_A receptors, independently from any further GABA_A-mediated inhibition in SII. By estimating the transfer function between SI and SII activation under placebo conditions, we were able to predict SII activity for the administration of GABA receptors agonists under the assumption that GABA exclusively acts at the level of SI. By comparing measured and predicted data, we propose a model in which the initial activation of SI is modulated through GABA_A receptors and subsequently propagated to SII, without any significant further inhibition. In addition, initial GABA_A effects in SI appear to be strongly potentiated with time, selectively in SI but not in SII.

Medical and gynecological comorbidities in adult women with Turner syndrome: our multidisciplinary clinic experience

Objective: Women with Turner syndrome (TS) are at increased risk for chronic health conditions. Reports describing the presence of comorbidities in older adult women with TS are limited. This study aimed to examine the prevalence of endocrine, gynecological, and other chronic medical conditions in a cohort of adult TS patients.Methods: A retrospective chart review was conducted on patients seen between 1 February 2015 and 1 July 2018 in a multidisciplinary TS clinic at a university-based ambulatory hospital in Toronto, Canada. All women seen at the TS clinic with a diagnosis of TS aged >18 years were included. The prevalence of diseases was determined overall and stratified by age (<40 and ≥40 years). Statistical comparisons were done using the chi-square test. The main study outcomes included the presence of comorbidities.Results: Of 122 adult women with TS, 24.5% had hypothyroidism, 16% had dysglycemia, and 27.9% had decreased bone mass. Hypothyroidism and dysglycemia were more common among older women (respectively age ≥40 years vs. age <40 years: 36.7% vs. 17.8%, p = 0.018; and 24.5% vs. 5.5%, p = 0.023). Gynecological conditions were identified in 35% of patients and were more common among older women (42.8% age ≥40 years vs. 13.7% age <40 years, p = 0.003). Overall, 41% had hearing impairment, 36.1% had cardiac abnormalities, 14.8% had hypertension, 18.8% had renal abnormalities, and 9% had celiac disease.Conclusions: The results of this study indicate a high prevalence of medical conditions in women with TS, especially those ≥40 years of age. Our study underscores the importance of multidisciplinary adult TS clinics for ongoing screening and management of comorbidities.

Photon Subtraction by Many-Body Decoherence

We experimentally and theoretically investigate the scattering of a photonic quantum field from another stored in a strongly interacting atomic Rydberg ensemble. Considering the many-body limit of this problem, we derive an exact solution to the scattering-induced spatial decoherence of multiple stored photons, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis reveals a correlated coherence-protection process in which the scattering from one excitation can shield all others from spatial decoherence. We discuss how this effect can be used to manipulate light at the quantum level, providing a robust mechanism for single-photon subtraction, and experimentally demonstrate this capability.

A direct access to heterobimetallic complexes by roll-over cyclometallation

Complexes of the type [Cp*Ir(N,N')Cl]⁺ (N,N' = 2-(2-dialkylaminopyrimidin-4-yl)pyrimidine) can undergo roll-over cyclometallation leading to a novel N,N'-donor site. Following this strategy heterobimetallic complexes including iridium(iii) and a Group X metal centre in the oxidation state +II were achieved.

The intricate network between the p34 and p44 subunits is central to the activity of the transcription/DNA repair factor TFIIH

The general transcription factor IIH (TFIIH) is a multi-protein complex and its 10 subunits are engaged in an intricate protein-protein interaction network critical for the regulation of its transcription and DNA repair activities that are so far little understood on a molecular level. In this study, we focused on the p44 and the p34 subunits, which are central for the structural integrity of core-TFIIH. We solved crystal structures of a complex formed by the p34 N-terminal vWA and p44 C-terminal zinc binding domains from Chaetomium thermophilum and from Homo sapiens. Intriguingly, our functional analyses clearly revealed the presence of a second interface located in the C-terminal zinc binding region of p34, which can rescue a disrupted interaction between the p34 vWA and the p44 RING domain. In addition, we demonstrate that the C-terminal zinc binding domain of p34 assumes a central role with respect to the stability and function of TFIIH. Our data reveal a redundant interaction network within core-TFIIH, which may serve to minimize the susceptibility to mutational impairment. This provides first insights why so far no mutations in the p34 or p44 TFIIH-core subunits have been identified that would lead to the hallmark nucleotide excision repair syndromes xeroderma pigmentosum or trichothiodystrophy.

Children and adolescents with cystic fibrosis display moderate bone microarchitecture abnormalities: data from high-resolution peripheral quantitative computed tomography

We investigated whether bone microstructure assessed by high-resolution peripheral quantitative tomography (HR-pQCT) could be altered in children and teenagers with cystic fibrosis (CF). In comparison to their healthy counterparts, bone microstructure was mildly affected at the tibial level only.

INTRODUCTION

Cystic fibrosis-related bone disease (CFBD) may alter bone health, ultimately predisposing patients to bone fractures. Our aim was to assess bone microstructure using high-resolution peripheral quantitative tomography (HR-pQCT) in a cohort of children and teenagers with CF in comparison to age-, puberty-, and gender-matched healthy volunteers (HVs).

METHODS

In this single-center, prospective, cross-sectional study, we evaluated the HR-pQCT bone parameters of CF patients and compared them to those of the healthy volunteers.

RESULTS

At a median age of 15.4 [range, 10.5-17.9] years, 37 CF patients (21 boys) with 91% [range, 46-138%] median forced expiratory volume in 1 s were included. At the ultradistal tibia, CF patients had a smaller bone cross-sectional area (579 [range, 399-1087] mm²) than HVs (655 [range, 445-981] mm²) (p = 0.027), related to a decreased trabecular area, without any significant differences for height. No other differences were found (trabecular number, separation, thickness, or distribution) at the radial or tibial levels. Bone structure was different in patients receiving ursodeoxycholic acid and those bearing two F508del mutations.

CONCLUSION

In our cohort of children and teenagers with good nutritional and lung function status, bone microstructure evaluated with HR-pQCT was not severely affected. Minimal microstructure abnormalities observed at the tibial level may be related to the cystic fibrosis transmembrane conductance regulator defect alone; the long-term consequences of such impairment will require further evaluation.

Clinical outcome after alternative treatment of scaphoid fractures and nonunions

PURPOSE

Achieving stable fixation of scaphoid fractures and nonunions continues to be a challenge. Compression screw fixation has been the current standard surgical procedure. However, in some cases, bone healing cannot be achieved and requires further revision. Recent series reintroduced volar plating as valid option for stable fixation. The aim of the study was to review clinical outcome of alternative scaphoid treatment.

METHODS

From 2011 to 2014, nine patients with scaphoid fracture were treated by Headless Compression Screw (HCS) and seven patients with scaphoid nonunion by HCS or volar mini condylar plate with bone graft. The average age was 34.4 years and the average time to follow-up was 19.3 months. From 1996 to 1998, 38 patients with scaphoid nonunion were treated using compression screw (S-group) or volar mini condylar plate (P-group) with bone graft. The average age was 39.6 years and the average time to follow-up was 26.2 months.

RESULTS

The union rate was 100%. For scaphoid fractures, the mean Modified Mayo Wrist Score (MMWS) was 94.1 and the DASH score 7.4. From 2011 to 2014, the MMWS was 87.9 and the DASH score 7 in scaphoid nonunions. In the period between 1996 and 1998, the MMWS was 67.2 in the P-group and 58.6 in the S-group, and the DASH score 16.8 and 28.2.

CONCLUSIONS

Our study demonstrated that appropriate application of the HCS was able to produce very satisfactory results in scaphoid fractures and nonunions. In our opinion, however, the method of scaphoid plate osteosynthesis can achieve a higher degree of stability, particularly rotational stability, in case of multifragmentary avascular scaphoid nonunions.