Large vessel vasculitis in elderly patients: early diagnosis and steroid-response evaluation with FDG-PET/CT and contrast-enhanced CT

Large vessel vasculitis (LVV) is an often-reported cause of inflammation of unknown origin (IUO) in elderly people. The objective of this study was to describe the usefulness of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and contrast-enhanced CT in early diagnosis and treatment follow-up of patients with LVV presenting as elderly onset IUO. We retrospectively compared contrast-enhanced CT findings and FDG-PET/CT findings of the patients diagnosed with LVV and 11 controls; all subjects were 50 years of age or older. We evaluated maximum standardised uptake value (SUV_max) and PET score of the aortic wall for quantitative comparison of FDG-PET/CT findings. We measured the aortic wall thickness (W) and its ratio against the radius (W/R) for quantitative comparison of aortic wall thickening by contrast-enhanced CT. After steroid treatment, we compared these values with those pre-treatment. Of 124 patients who were hospitalised due to advanced age and IUO, 88 underwent FDG-PET/CT and contrast-enhanced CT. Abnormal findings were observed on images from 78 patients. The findings were indicative of LVV in 13 patients (10.5 %), of whom more than half had only non-specific symptoms. Patients with LVV had significantly higher aortic wall SUV_max (3.85 vs. 1.95), PET scores by FDG-PET/CT, and aortic wall thicknesses by contrast-enhanced CT (3.8 vs. 2.6 mm) than controls. Significant improvement in aortic wall thickening was evidenced by reduced PET scores and by contrast-enhanced CT findings in patients who were followed up after treatment. LVV is an important cause of IUO with non-specific symptoms in elderly patients. Imaging examination comprising contrast-enhanced CT and FDG-PET/CT is useful for early diagnosis and early treatment evaluation of LVV, allowing for amelioration of reversible aortic wall thickening.     

Conformational alterations in unidirectional ion transport of a light-driven chloride pump revealed using X-ray free electron lasers

Light-driven chloride-pumping rhodopsins actively transport anions, including various halide ions, across cell membranes. Recent studies using time-resolved serial femtosecond crystallography (TR-SFX) have uncovered the structural changes and ion transfer mechanisms in light-driven cation-pumping rhodopsins. However, the mechanism by which the conformational changes pump an anion to achieve unidirectional ion transport, from the extracellular side to the cytoplasmic side, in anion-pumping rhodopsins remains enigmatic. We have collected TR-SFX data of Nonlabens marinus rhodopsin-3 (NM-R3), derived from a marine flavobacterium, at 10-µs and 1-ms time points after photoexcitation. Our structural analysis reveals the conformational alterations during ion transfer and after ion release. Movements of the retinal chromophore initially displace a conserved tryptophan to the cytoplasmic side of NM-R3, accompanied by a slight shift of the halide ion bound to the retinal. After ion release, the inward movements of helix C and helix G and the lateral displacements of the retinal block access to the extracellular side of NM-R3. Anomalous signal data have also been obtained from NM-R3 crystals containing iodide ions. The anomalous density maps provide insight into the halide binding site for ion transfer in NM-R3.

Microbial ion-pumping rhodopsins are integral membrane proteins that actively transport ions across membranes upon light stimulation (1). Bacteriorhodopsin (bR) and halorhodopsin (HR) are well-known microbial ion-pumping rhodopsins found in halophilic archaea (2, 3). bR is a light-driven outward proton pump and HR is a light-driven inward anion pump, specific for chloride ion. Microbial ion-pumping rhodopsins possess common structural features consisting of seven α-helices with an all-trans retinal covalently bound to a lysine residue as the chromophore, despite the transport of different ions (4). The retinal undergoes photoisomerization from the all-trans to 13-cis configuration, which initiates the photocycle accompanied by several intermediates to export ions (4, 5). Its light-controllable function is suitable for optogenetics applications for manipulating cells, such as neurons, by changing the ion concentration inside or outside the membrane (6, 7). In fact, microbial rhodopsins, including channelrhodopsins and HRs, are employed as optogenetic tools (8–10).Nonlabens marinus rhodopsin-3 (NM-R3) is a light-driven chloride pump recently discovered in a marine flavobacterium (11). It is a distinct chloride pump from HRs and shows low amino acid sequence homology with HRs (11). To date, HR-type chloride pumps have been found in haloarchaea, marine bacteria, and cyanobacteria, including Halobacterium salinarum, Natronomonas pharaonis, and Mastigocladopsins repens, with sequence identities of 20%, 21%, and 20% to NM-R3, respectively (3, 12–15). Interestingly, NM-R3 has higher sequence identity (36%) to Krokinobacter rhodopsin 2 (KR2), a sodium pump found in Krokinobacter eikastus (16). NM-R3 possesses a unique NTQ motif (Asn98, Thr102, Gln109) in the third helix (helix C), which corresponds to key residues (DTD motif, Asp85, Thr89, Asp96) for proton transport in bR (11, 17, 18) (SI Appendix, Table S1). Asp85 acts as the primary proton acceptor of bR from the protonated Schiff-base (PSB), with assistance from Thr89 and Asp96, which is the proton donor (5, 17, 18). HRs from haloarchaea have a highly conserved TSA (Thr, Ser, Ala) motif, while the Ala residue is replaced by Asp in HR from cyanobacteria (19). In the X-ray crystal structure of NM-R3 (SI Appendix, Fig. S1A), a chloride ion located between the PSB and Asn98 (SI Appendix, Fig. S1B) is stabilized by the positive charge of the PSB (20). The position of this chloride ion is similar to those in the H. salinarum HR and N. pharaonis HR (NpHR) structures except for Thr and Ser, which correspond to Asn98 and Thr102 in NM-R3, respectively (20–22). Several amino acid residues around the retinal, including Arg95, Trp99, Trp201, and Asp231, are highly conserved among ion-pumping rhodopsins. Previous spectroscopic studies suggested that NM-R3 displays a similar sequence of intermediates, with K-, L-, N-, and O-like species, as in other HRs (23) (Fig. 1A). Recently, intermediate structures of NM-R3 obtained by low-temperature trapping X-ray crystallography and serial femtosecond crystallography (SFX) have been reported (24, 25). However, the detailed ion-pump mechanism still remains unclear, due to the lack of dynamic structures of anion transport at atomic resolution.Open in a separate windowFig. 1.TR-visible absorption spectroscopy for microcrystals. (A) Photocycle model of NM-R3 in the 1 M NaCl buffer solution (23). (B) TR difference spectra ΔA upon the 532-nm excitation. The difference was calculated by subtracting the spectrum of NM-R3. (C) Global fitting analysis with two exponentials. The A₁ and A₂ amplitude spectra correspond to the differences of [ΔA_O – ΔA_{10 µs}] and [ΔA_{200 ms} − ΔA_O], respectively. Here, ΔA_O represents the difference spectrum of the O intermediate minus NM-R3. (D) The isomeric forms of the retinal chromophore in bacterial-type rhodopsins.Time-resolved serial femtosecond crystallography (TR-SFX) is a powerful tool for visualizing reactions and motions in proteins at the atomic level (26–28). In SFX, myriads of microcrystals are continuously injected by a sample injector into an irradiation point of X-ray free electron lasers (XFELs) at room temperature, thus providing diffraction patterns before the onset of radiation damage by the intense X-ray pulse. Combined with a visible-light pump laser for reaction initiation, TR-SFX has been applied to light-driven ion pumps to observe the structural dynamics during the ion transfer. While TR-SFX has revealed femto-to-millisecond structural dynamics in light-driven cation pumps, including bR and KR2 (29–31), TR-SFX studies of anion pumps have been limited to early-stage structures adopted at picoseconds after light illumination (32). In addition, although NM-R3 pumps a chloride ion (Cl⁻) as a physiological substrate, it can also transport bromide (Br⁻), iodide (I⁻), and other anions from the extracellular side to the cytoplasmic side (23). I⁻ or Br⁻ serves as a marker for tracking the positions of ions, due to the greater number of electrons, whereas Cl⁻ is less distinguishable in X-ray crystallography. Therefore, TR-SFX experiments using I⁻ or Br⁻ are expected to directly visualize the process of ion transport.Here, we report the conformational alterations in NM-R3 during Br⁻ or I⁻ pumping, obtained by both TR-SFX and time-resolved spectroscopy of crystals. The resulting sequence of movements in NM-R3 demonstrates how the chloride pump transports anions with a large ionic radius and prevents the backflow of anions from the cytoplasmic side.     

Monitoring and switching of cortico-basal ganglia loop functions by the thalamo-striatal system

Recent physiological and tract tracing studies revealed tight coupling of the centre médian and parafascicular nuclei (the CM-Pf complex), which are posterior intralaminar nuclei (ILN) of the thalamus, with basal ganglia circuits. These nuclei have previously been classified as part of the ascending reticulo-thalamo-cortical activating system, with studies of single neuron activity and of interruption of neuronal activity suggested that they participate in the processes of sensory event-driven attention and arousal, particularly in the context of unpredicted events or events contrary to predictions. In this article, we propose a hypothetical model that envisions that the CM-Pf complex functions in two different modes depending on the predictability of external events, i.e., one for monitoring 'top-down' biased control through the cortico-basal ganglia loop system for selecting signals for action and cognition and the other for switching from biased control to 'bottom-up' control based on the signals of salient external events. This model provides a new insight into the function of the CM-Pf complex and should lead to a better understanding of this important brain system.     

Surgical outcome of radial osteotomy for Kienböck's disease-minimum 10 years of follow-up

PURPOSE: Long-term results of radial osteotomy for Kienb?ck's disease seldom are seen in the literature. The purpose of this study was to report the minimum 10-year results and to compare them with the 5-year results to determine whether the favorable intermediate-term results were maintained. METHODS: Twenty-five patients who underwent radial osteotomy were followed-up for a mean period of 14.5 years. They were examined for pain, grip strength, and wrist range of motion (ROM). Through a review of clinical records, 5-year postoperative results were collected. The carpal height ratio and St?hl's index were measured and the x-rays were inspected for osteoarthritic changes. We devised an original lunate grade to evaluate radiologic improvement of the ischemic lunate. Overall results were evaluated using Cooney's wrist function score and Nakamura's scoring system for Kienb?ck's disease. The long-term results were compared with both the preoperative status and the 5-year results. RESULTS: Pain, ROM, and grip strength were improved significantly after surgery, and the results were maintained for a long period. Carpal height ratio and St?hl's index did not show significant improvements but ischemic lunate showed certain radiologic improvements with time by the lunate grade system. Osteoarthritic changes were observed in 54% of patients at 5 years and in 73% of patients at the final follow-up evaluation, but the arthrosis generally was mild and did not affect the clinical results. Cooney's wrist function score was excellent or good in 96% of the patients, and the results with Nakamura's scoring system for Kienb?ck's disease were excellent or good in 68% of the patients at the final follow-up evaluation. The percentages were the same 5 years after surgery. CONCLUSIONS: Radial osteotomy for Kienb?ck's disease is a reasonable treatment option and clinical improvement lasts for a long period of time. Although radiologic improvement was not drastic, the inner structure such as sclerotic change or bone cysts of the lunate improved with time, indicating healing of the ischemic lunate. Severe osteoarthritic change or proximal migration of the capitate can be avoided.     

Sonographic diagnosis of acute injuries of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb

PURPOSE: To evaluate the significance of the ultrasonographic appearance of the aponeurosis for deciding the best treatment for ulnar collateral ligament (UCL) injuries of the thumb metacarpophalangeal joint. METHODS: Fourteen patients (11 men, 3 women; mean age, 41 years; range, 15-66 years) who had an acute UCL tear were included. All patients were examined by ultrasonography (US) with a 7.5-MHz transducer and subsequently underwent surgery. The ultrasonographic findings were compared to the intraoperative findings. RESULTS: UCL injuries were classified into two types by US according to the appearance of aponeurosis and its spatial relationship with the UCL: the intra-aponeurosis type (5 patients) and the extra-aponeurosis type (9 patients). In the 5 patients with intra-aponeurosis, ultrasonographic findings were well consistent with intraoperative findings. In contrast, extra-aponeurosis cases contained two different pathologies: of the 9 patients, 7 had so-called 'Stener lesions', one showed folding of a ruptured capsule, and one showed a ruptured aponeurosis. CONCLUSIONS: Because US is highly reliable in differentiating intra-aponeurosis from extra-aponeurosis types of injuries, the aponeurosis is a more reliable reference than Stener lesion for treatment decision by US.     

Axonal regeneration from the spinal cord to peripheral nerve induced by end-to-side neurorrhaphy Evidence from acetylcholinesterase staining and Fluorogold retrograde tracing

BACKGROUND： In recent years, surgeons have advocated root or trunk repair of avulsed nerve roots for overall recovery. However, donor nerves pose a major problem, because they do not contain adequate numbers of axons. Moreover, the procedures lead to nerve deficits in the donor nerve following transplantation. OBJECTIVE： To observe whether axonal regeneration occurs by end-to-side neurorrhaphy in the peripheral nerve and spinal cord. DESIGN, TIME AND SETTING： A neuroanatomical, randomized, controlled, animal study was performed at Functional Anatomy Lab in Nagoya University School of Medicine from May 2002 to July 2003. MATERIALS： Fluorogold was purchased from Fluorochrome, LLC, USA. BX50 light microscope and fluorescent microscope were purchased from Olympus, Japan. METHODS： A total of 21 rats were randomly divided into three groups, and the posterior avulsion injury model （C6-8） of the brachial plexus was performed. In the ventral root graft group, the avulsed C7 ventral roots were reanastomosed to the small anterior lateral aspect window of the spinal cord via nerve grafts. In the dorsal root graft group, the C7 dorsal roots were reanastomosed at the small pia mater window of the posterior lateral aspect of the spinal cord via nerve grafts. In the control group, the avulsed nerve roots were not repaired. MAIN OUTCOME MEASURES： The nerve grafts were collected from the ventral and dorsal root graft groups, and the C7 proximal nerve end was collected from the control group. Acetylcholinesterase staining was performed on the tissue. Fluorogold retrograde tracing technique was applied to determine the origin of the regenerating axons. RESULTS： Results showed that acetylcholine-positive axons existed in nerve grafts of the ventral and dorsal root graft groups. However, axons were not found in the avulsed nerve roots of the control group. Fluorogold retrograde tracing confirmed the presence of fluorogold-containing neurons in the ventral and dorsal horn of the ventral and dorsal root graft groups. Fluorogold-positive neurons were not observed in the control group. CONCLUSION： End-to-side neurorrhaphy induced axonal regeneration from the spinal cord to the peripheral nervous system.