3-Nitrotyrosine shortens axons of non-dopaminergic neurons by inhibiting mitochondrial motility

3-Nitrotyrosine (3-NT), a byproduct of oxidative and nitrosative stress, is implicated in age-related neurodegenerative disorders. Current literature suggests that free 3-NT becomes integrated into the carboxy-terminal domain of α-tubulin via the tyrosination/detyrosination cycle. Independently of this integration, 3-NT has been associated with the cell death of dopaminergic neurons. Given the critical role of tyrosination/detyrosination in governing axonal morphology and function, the substitution of tyrosine with 3-NT in this process may potentially disrupt axonal homeostasis, although this aspect remains underexplored. In this study, we examined the impact of 3-NT on the axons of cerebellar granule neurons, which is used as a model for non-dopaminergic neurons. Our observations revealed axonal shortening, which correlated with the incorporation of 3-NT into α-tubulin. Importantly, this axonal effect was observed prior to the onset of cellular death. Furthermore, 3-NT was found to diminish mitochondrial motility within the axon, leading to a subsequent reduction in mitochondrial membrane potential. The suppression of syntaphilin, a protein responsible for anchoring mitochondria to microtubules, restored the mitochondrial motility and axonal elongation that were inhibited by 3-NT. These findings underscore the inhibitory role of 3-NT in axonal elongation by impeding mitochondrial movement, suggesting its potential involvement in axonal dysfunction within non-dopaminergic neurons.

Tubulin Polyglutamylation by TTLL1 and TTLL7 Regulate Glutamate Concentration in the Mice Brain

As an important neurotransmitter, glutamate acts in over 90% of excitatory synapses in the human brain. Its metabolic pathway is complicated, and the glutamate pool in neurons has not been fully elucidated. Tubulin polyglutamylation in the brain is mainly mediated by two tubulin tyrosine ligase-like (TTLL) proteins, TTLL1 and TTLL7, which have been indicated to be important for neuronal polarity. In this study, we constructed pure lines of Ttll1 and Ttll7 knockout mice. Ttll knockout mice showed several abnormal behaviors. Matrix-assisted laser desorption/ionization (MALDI) Imaging mass spectrometry (IMS) analyses of these brains showed increases in glutamate, suggesting that tubulin polyglutamylation by these TTLLs acts as a pool of glutamate in neurons and modulates some other amino acids related to glutamate.

A model for generating differences in microtubules between axonal branches depending on the distance from terminals

In the remodeling of axonal arbor, the growth and retraction of branches are differentially regulated within a single axon. Although cell-autonomously generated differences in microtubule (MT) turnover are thought to be involved in selective branch regulation, the cellular system whereby neurons generate differences of MTs between axonal branches has not been clarified. Because MT turnover tends to be slower in longer branches compared with neighboring shorter branches, feedback regulation depending on branch length is thought to be involved. In the present study, we generated a model of MT lifetime in axonal terminal branches by adapting a length-dependent model in which parameters for MT dynamics were constant in the arbor. The model predicted that differences in MT lifetime between neighboring branches could be generated depending on the distance from terminals. In addition, the following points were predicted. Firstly, destabilization of MTs throughout the arbor decreased the differences in MT lifetime between branches. Secondly, differences of MT lifetime existed even before MTs entered the branch point. In axonal MTs in primary neurons, treatment with a low concentration of nocodazole significantly decreased the differences of detyrosination (deTyr) and tyrosination (Tyr) of tubulins, indicators of MT turnover. Expansion microscopy of the axonal shaft before the branch point revealed differences in deTyr/Tyr modification on MTs. Our model recapitulates the differences in MT turnover between branches and provides a feedback mechanism for MT regulation that depends on the axonal arbor geometry.

Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Focal Hand Dystonia: A Pilot Study

Background

The efficacy of magnetic resonance‐guided focused ultrasound (MRgFUS) thalamotomy for the treatment of focal hand dystonia (FHD) is not well known.

Objective

We aimed to prospectively investigate the efficacy of MRgFUS thalamotomy for the treatment of FHD.

Methods

We performed MRgFUS thalamotomy of the ventro‐oral (Vo) nucleus in 10 patients with FHD. We evaluated the scores of the Writer's Cramp Rating Scale (WCRS, 0–30; higher scores indicating greater severity), Tubiana Musician's Dystonia Scale (TMDS, 0–5; lower scores indicating greater severity), and Arm Dystonia Disability Scale (ADDS, 0%–100%; lower scores indicating greater disability) at baseline and 3 and 12 months post‐treatment.

Results

WCRS, TMDS, and ADDS scores significantly improved from 6.3 ± 2.7, 1.4 ± 0.5, and 58.7% ± 14.3% at baseline to 1.6 ± 3.1 (P = 0.011), 5.0 ± 0 (P = 0.0001), and 81.6% ± 22.9% (P = 0.0229) at 12 months, respectively. There was one prolonged case of dysarthria at 12 months.

Conclusion

We show that MRgFUS Vo‐thalamotomy significantly improved FHD. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Reliability of Residual Tumor Estimation Based on Navigation Log

The mass of residual tumors has previously been estimated using time-series records of the position of surgical instruments acquired from neurosurgical navigation systems (navigation log). This method has been shown to be useful for rapid evaluation of residual tumors during resection. However, quantitative analysis of the method’s reliability has not been sufficiently reported. The effect of poor log coverage is dominant in previous studies, in that it did not highlight other disturbance factors, such as intraoperative brain shift. We analyzed 25 patients with a high log-acquisition rate that was calculated by dividing the log-available time by the instrument-use time. We estimated the region of resection using the trajectory of surgical instrument that was extracted from the navigation log. We then calculated the residual tumor region and measured its volume as log-estimation residual tumor volume (RTV). We evaluated the correlation between the log-estimation RTV and the RTV in the post-resection magnetic resonance (MR) image. We also evaluated the accuracy of detecting the residual tumor mass using the estimated residual tumor region. The log-estimation RTV and the RTV in the post-resection MR image were significantly correlated (correlation coefficient = 0.960; P <0.001). The presence of patient-wise residual tumor mass was detected with a sensitivity of 81.8% and a specificity of 92.9%. The individual residual tumor mass was detected with a positive predictive value of 72%. Estimation of residual tumor with adequate log coverage appears to be a suitable method with a high reliability. This method can support rapid decision-making during resection.

Correlation between fractional anisotropy changes in the targeted ventral intermediate nucleus and clinical outcome after transcranial MR-guided focused ultrasound thalamotomy for essential tremor: results of a pilot study

OBJECTIVE

This study evaluated changes of fractional anisotropy (FA) in the ventral intermediate nucleus (VIM) of the thalamus after transcranial MR-guided focused ultrasound (TcMRgFUS) thalamotomy and their associations with clinical outcome.

METHODS

Clinical and radiological data of 12 patients with medically refractory essential tremor (mean age 76.5 years) who underwent TcMRgFUS thalamotomy with VIM targeting were analyzed retrospectively. The Clinical Rating Scale for Tremor (CRST) score was calculated before and at 1 year after treatment. Measurements of the relative FA (rFA) values, defined as ratio of the FA value in the targeted VIM to the FA value in the contralateral VIM, were performed before thalamotomy, and 1 day and 1 year thereafter.

RESULTS

TcMRgFUS thalamotomy was well tolerated and no long-term complications were noted. At 1-year follow-up, 8 patients demonstrated relief of tremor (improvement group), whereas in 4 others persistent tremor was noted (recurrence group). In the entire cohort, mean rFA values in the targeted VIM before treatment, and at 1 day and 1 year after treatment, were 1.12 ± 0.15, 0.44 ± 0.13, and 0.82 ± 0.22, respectively (p < 0.001). rFA values were consistently higher in the recurrence group compared with the improvement group, and the difference reached statistical significance at 1 day (p < 0.05) and 1 year (p < 0.01) after treatment. There was a statistically significant (p < 0.01) positive correlation between rFA values in the targeted VIM at 1 day after thalamotomy and CRST score at 1 year after treatment. Receiver operating characteristic curve analysis revealed that the optimal cutoff value of rFA at 1 day after thalamotomy for prediction of symptomatic improvement at 1-year follow-up is 0.54.

CONCLUSIONS

TcMRgFUS thalamotomy results in significant decrease of rFA in the targeted VIM, at both 1 day and 1 year after treatment. Relative FA values at 1 day after treatment showed significant correlation with CRST score at 1-year follow-up. Therefore, FA may be considered a possible imaging biomarker for early prediction of clinical outcome after TcMRgFUS thalamotomy for essential tremor.

5965Perimatrial inflammation measured by fluoine-18-fluorodeoxyglucose-positron emission tomography/computed tomography to predict new-onset atrial fibrillation

Background

Fluoine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is a useful modality of inflammatory disease. Epicardial adipose tissue (EAT) contains abundant ganglionated plexi, therefore EAT inflammation may cause atrial arrhythmia, such as atrial premature contraction (APC) and atrial fibrillation (AF). Previous studies have shown that inflammatory activity of EAT has relation to the presence of AF. However, it is unknown whether EAT inflammation contributes to the occurrence of AF.

Methods

Out of 20720 examinees who underwent FDG-PET/CT for screening of cancer in the years 2012–2018, 151 (aged 65.6±12.0 years old, 62 females) had ambulatory electrocardiographic monitoring (Holter ECG) within a year and non-detection of AF. Standardized uptake value (SUV) was measured in fat adjacent to roof of left atrium (ROOF), atrioventricular groove (AV), left main coronary artery (LMT), and right ventricular blood pool (RV). In order to correct for blood pool activity, SUV of ROOF, AV, and LMT were divided by SUV of RV respectively, yielding target-to-background ratio (TBR). As regards to arterial inflammation, measurements were performed with SUV in ascending aorta (A-Ao) and in superior vena cava (SVC) as blood pool. In the same way, SUV of A-Ao was divided by SUV of SVC, yielding TBR.

Results

According to Holter ECG, APC≥100 beats per day was seen in 60 patients (Group A), but not in the other 91 (Group B). In Group A, TBR of ROOF, AV, and LMT were all significantly higher than Group B (p<0.001, p=0.004, and p=0.008, respectively). During a median follow-up of 179 days, new-onset AF was diagnosed in 7 patients (4 in Group A (6.7%), 3 in Group B (3.3%), p=0.046). There was significant difference in TBR of ROOF between patients with and without new-onset AF (p<0.001), but not in TBR of AV and LMT. In addition, no significant difference was observed in TBR of A-Ao between these two groups. In the Cox proportional hazard analysis, TBR of ROOF was found to be an independent predictor of new-onset AF (odds ratio 40.1, 95% confidence interval 6.05 to 265.9, p<0.001).

Conclusions

Although EAT inflammation evaluated by SUV is related to frequent APCs, only in fat adjacent to roof of left atrium is associated with and predicts future occurrence of AF. Arterial inflammation measured by SUV has no relation to atrial arrhythmia.

A single case of MRI-guided focused ultrasound ventro-oral thalamotomy for musician's dystonia

Musician's dystonia (MD) is a type of focal hand dystonia that develops only while playing musical instruments and interferes with skilled and fine movements. Lesioning of the ventro-oral (Vo) nucleus of the thalamus (Vo-thalamotomy) using radiofrequency can cause dramatic improvement in MD symptoms. Focused ultrasound (FUS) can make intracranial focal lesions without an incision. The authors used MRI-guided FUS (MRgFUS) to create a lesion on the Vo nucleus to treat a patient with MD. Tubiana's MD scale (TMDS) was used to evaluate the condition of musical play ranging from 1 to 5 (1: worst, 5: best). The patient was a 35-year-old right-handed man with involuntary flexion of the right second, third, and fourth fingers, which occurred while playing a classical guitar. Immediately after therapeutic sonications of FUS Vo-thalamotomy, there was dramatic improvement in the MD symptoms. The TMDS scores before; at 0 and 1 week after; and at 1, 3, 6, and 12 months after MRgFUS Vo-thalamotomy were 1, 4, 4, 5, 5, 5, and 5, respectively. No complications were observed. Focused ultrasound Vo-thalamotomy can be an effective treatment for MD.

Sonodynamic Therapy With Anticancer Micelles and High-Intensity Focused Ultrasound in Treatment of Canine Cancer

Sonodynamic therapy (SDT) is a minimally invasive anticancer therapy involving a chemical sonosensitizer and high-intensity focused ultrasound (HIFU). SDT enables the reduction of drug dose and HIFU irradiation power compared to those of conventional monotherapies. In our previous study, mouse models of colon and pancreatic cancer were used to confirm the effectiveness of SDT vs. drug-only or HIFU-only therapy. To validate its usefulness, we performed a clinical trial of SDT using an anticancer micelle (NC-6300) and our HIFU system in four pet dogs with spontaneous tumors, including chondrosarcoma, osteosarcoma, hepatocellular cancer, and prostate cancer. The fact that no adverse events were observed, suggests the usefulness of SDT.

Postoperative cognitive dysfunction after sevoflurane or propofol general anaesthesia in combination with spinal anaesthesia for hip arthroplasty

It is unknown if the type of general anaesthetic used for maintenance of anaesthesia affects the incidence of postoperative cognitive dysfunction (POCD). The aim of this study was to compare the incidence of POCD in patients administered either sevoflurane or propofol for maintenance of anaesthesia during total hip replacement surgery. Following administration of a spinal anaesthetic, patients received either sevoflurane (n=121) or propofol (n=171) at the discretion of the anaesthetist for maintenance of general anaesthesia to maintain the processed electroencephalogram (bispectral index, BIS) under 60. POCD was assessed postoperatively at day 7, three months, and 12 months using a neurocognitive test battery. There was no statistically significant difference between the incidence of POCD at any timepoint with sevoflurane compared to propofol. The mean BIS was significantly lower in the sevoflurane group than in the propofol group (mean BIS 44.3 [standard deviation, SD 7.5] in the sevoflurane group versus 53.7 [SD 8.1] in the propofol group, <i>P</i>=0.0001). However, there was no statistically significant association between intraoperative BIS level and the incidence of POCD at any timepoint. Our results suggest that the incidence of POCD is not strongly influenced by the type of anaesthesia used in elderly patients.

PCLO rs2522833-mediated gray matter volume reduction in patients with drug-naive, first-episode major depressive disorder

Major depressive disorder (MDD) has been linked to differences in the volume of certain areas of the brain and to variants in the piccolo presynaptic cytomatrix protein (PCLO), but the relationship between PCLO and brain morphology has not been studied. A single-nucleotide polymorphism (SNP) in PCLO, rs2522833, is thought to affect protein stability and the activity of the hypothalamic-pituitary-adrenal axis. We investigated the relationship between cortical volume and this SNP in first-episode, drug-naive patients with MDD or healthy control subjects. Seventy-eight participants, including 30 patients with MDD and 48 healthy control subjects, were recruited via interview. PCLO rs2522833 genotyping and plasma cortisol assays were performed, and gray matter volume was estimated using structural magnetic resonance images. Among the individuals carrying the C-allele of PCLO rs2522833, the volume of the left temporal pole was significantly smaller in those with MDD than in healthy controls (family-wise error-corrected, P=0.003). No differences were detected in other brain regions. In addition, the C-carriers showed a larger volume reduction in the left temporal pole than those in the individuals with A/A genotype (P=0.0099). Plasma cortisol levels were significantly higher in MDD-affected C-carriers than in the healthy control C-carriers (12.76±6.10 vs 9.31±3.60 nm, P=0.045). We conclude that PCLO SNP rs2522833 is associated with a gray matter volume reduction in the left temporal pole in drug-naive, first-episode patients with MDD carrying the C-allele.

Anterior cruciate ligament reconstruction does not induce further gamma loop abnormalities on the intact side of the quadriceps femoris: A longitudinal study

This study aimed to investigate the effect of surgery on the gamma loop of the quadriceps on the side with an intact knee in patients with anterior cruciate ligament (ACL) injuries. We compared longitudinally the response of alpha motor neurons to vibration stimulation of the quadriceps on the side with an intact knee before and after ACL reconstruction. To evaluate alpha motor neuron response, we measured the maximal knee extension strength and integrated electromyography of the vastus medialis, vastus lateralis, and rectus femoris. After obtaining pre-vibration data from each subject, vibration stimulation was applied to the infrapatellar tendon, and the same measurements were performed immediately after stimulation. The results of this study showed that the response to prolonged vibration stimulation on the intact side of the quadriceps did not differ pre- and post-surgery. As vibration stimuli normally elicit a decrease in alpha motor neuron activity in normal individuals, abnormal responses to prolonged vibration stimulation of the quadriceps on the side with an intact knee might be observed in patients with ACL injuries. The abnormality of the gamma loop of the quadriceps on the side with an intact knee was probably induced by the rupture. Based on these results, we conclude that surgery does not induce further gamma loop abnormalities on the intact side of the quadriceps.

TENS Alleviates Muscle Weakness Attributable to Attenuation of Ia Afferents

Quadriceps weakness is a notable problem following knee damage. Research has shown effectiveness of TENS in improving Quadriceps weakness associated with arthrogenic muscle inhibition. However, these studies were not focused upon short term delivery of TENS, nor did they examine the potential mechanism(s). The present study examined the effect of 25-30 s of TENS upon weakness induced temporarily by a prolonged vibration. Subjects performed eccentric MVCs under 2 conditions (TENS and no-TENS). First, MVC was measured at baseline. For the TENS condition, TENS was applied to each subject's knee joint during a second MVC measurement after vibration. For no-TENS condition, TENS was not applied during the 2^nd MVC measurement. MVC between pre-and post-vibration stimulation were compared across the 2 conditions. The results showed that MVC and EMG of TENS-condition was larger than that of no-TENS condition. Our results suggest that TENS could partially restore α-motoneuron activation, despite the induced dysfunctional γ-loop. These results suggest that mechanisms independent of the γ-loop such as a direct facilitation of the QF α-motoneuron pool by a long latency spinal-reflex and/or supraspinal mechanisms appear more likely to be responsible. The findings provide further support for utilizing TENS, even when γ-loop dysfunction is present following joint damage.

Study of local intracellular signals regulating axonal morphogenesis using a microfluidic device

The establishment and maintenance of axonal patterning is crucial for neuronal function. To identify the molecular systems that operate locally to control axonal structure, it is important to manipulate molecular functions in restricted subcellular areas for a long period of time. Microfluidic devices can be powerful tools for such purposes. In this study, we demonstrate the application of a microfluidic device to clarify the function of local Ca²⁺ signals in axons. Membrane depolarization significantly induced axonal branch-extension in cultured cerebellar granule neurons (CGNs). Local application of nifedipine using a polydimethylsiloxane (PDMS)-based microfluidic device demonstrated that Ca²⁺ entry from the axonal region via L-type voltage-dependent calcium channels (L-VDCC) is required for branch extension. Furthermore, we developed a method for locally controlling protein levels by combining genetic techniques and use of a microfluidic culture system. A vector for enhanced green fluorescent protein (EGFP) fused to a destabilizing domain derived from E. coli dihydrofolate reductase (ecDHFR) is introduced in neurons by electroporation. By local application of the DHFR ligand, trimethoprim (TMP) using a microfluidic device, we were able to manipulate differentially the level of fusion protein between axons and somatodendrites. The present study revealed the effectiveness of microfluidic devices to address fundamental biological issues at subcellular levels, and the possibility of their development in combination with molecular techniques.

Kinesin-1 sorting in axons controls the differential retraction of arbor terminals

The ability of neurons to generate multiple arbor terminals from a single axon is crucial for establishing proper neuronal wiring. Although growth and retraction of arbor terminals are differentially regulated within the axon, the mechanisms by which neurons locally control their structure remain largely unknown. In the present study, we found that the kinesin-1 (Kif5 proteins) head domain (K5H) preferentially marks a subset of arbor terminals. Time-lapse imaging clarified that these arbor terminals were more stable than others, because of a low retraction rate. Local inhibition of kinesin-1 in the arbor terminal by chromophore-assisted light inactivation (CALI) enhanced the retraction rate. The microtubule turnover was locally regulated depending on the length from the branching point to the terminal end, but did not directly correlate with the presence of K5H. By contrast, F-actin signal values in arbor terminals correlated spatiotemporally with K5H, and inhibition of actin turnover prevented retraction. Results from the present study reveal a new system mediated by kinesin-1 sorting in axons that differentially controls stability of arbor terminals.

Treatment of vasospasm by balloon angioplasty: experimental studies and clinical experiences

The vasodilation mode and degree of the invasion caused by balloon angioplasty were experimentally examined. Assessment by light microscopy and scanning electron microscopy demonstrated that the invasion to the implanted arterial wall, taken from a patient who died from vasospasm, was minimized by the use of the balloon under the condition at 1 atm, 10 times for 10 seconds. Furthermore, we applied angioplasty to eight patients who developed severe vasospasm after subarachnoid haemorrhage, and five showed improvement in neurophysiological (transcranial Doppler sonography), neuroradiological, and clinical examinations. In addition, blood vessels obtained from one patient who died 10 days after angioplasty, demonstrated similar findings to those of the experimental studies. It can be said that angioplasty will be one of the effective therapeutic methods to manage vasospasm when it is applied under the conditions mentioned above.

Ttll9-/- mice sperm flagella show shortening of doublet 7, reduction of doublet 5 polyglutamylation and a stall in beating

Nine outer doublet microtubules in axonemes of flagella and cilia are heterogeneous in structure and biochemical properties. In mammalian sperm flagella, one of the factors to generate the heterogeneity is tubulin polyglutamylation, although the importance of the heterogeneous modification is unclear. Here, we show that a tubulin polyglutamylase Ttll9 deficiency (Ttll9(-/-)) causes a unique set of phenotypes related to doublet heterogeneity. Ttll9(-/-) sperm axonemes had frequent loss of a doublet and reduced polyglutamylation. Intriguingly, the doublet loss selectively occurred at the distal region of doublet 7, and reduced polyglutamylation was observed preferentially on doublet 5. Ttll9(-/-) spermatozoa showed aberrant flagellar beating, characterized by frequent stalls after anti-hook bending. This abnormal motility could be attributed to the reduction of polyglutamylation on doublet 5, which probably occurred at a position involved in the switching of bending. These results indicate that mammalian Ttll9 plays essential roles in maintaining the normal structure and beating pattern of sperm flagella by establishing normal heterogeneous polyglutamylation patterns.