Distal Arm Research Articles

A Rare Cause of Diffuse Forearm Swelling in an Infant.

1. Matthew Baker, MD* 2. Stephanie Todd, MD, FAAP†,‡ 3. Narendra S. Shet, MD†,‡ 1. *Children’s Hospital Los Angeles, Los Angeles, CA 2. †George Washington University School of Medicine, Washington, DC 3. ‡Children’s National Hospital, Washington, DC A 10-month-old previously healthy girl presents to the emergency department with new-onset fevers and progressive right forearm swelling, pain, and irritability after a diagnosis of a distal forearm fracture in the same arm 2 weeks earlier. Per the parents’ report, they initially sought care 2 weeks earlier when the child refused to bear weight with the right arm while crawling without any known history of trauma. Outside imaging was reported to be notable for nondisplaced distal radial and ulnar fractures, for which the patient was splinted. Although the family denied a history of trauma, due to the unclear etiology of the fractures, an evaluation for possible nonaccidental trauma was performed that was unrevealing, except for the noted radius and ulna fractures. Follow-up 1 week later had revealed a swollen forearm with repeated plain radiographs that demonstrated abundant periosteal reaction along the distal radius and ulna, presumably representing evidence of healing nondisplaced fractures given the duration since the initial injury (Fig 1). The arm remained swollen but compressible and nontender on examination. Due to the fever, as well as continued swelling of the right distal arm with decreased mobility and worsening pain and irritability, the parents present to …

Correlates of Fatigability in Patients With Spinal Muscular Atrophy.

To determine the associations between fatigability and muscle strength, motor function, neuromuscular junction (NMJ) function, and perceived fatigue in spinal muscular atrophy (SMA), we assessed 61 patients with SMA. Fatigability was defined as the inability to continue a 20-minute submaximal repetitive task of either walking or proximal or distal arm function and expressed as drop-out on the Endurance Shuttle Test Combined Score (ESTCS). We assessed muscle strength with the Medical Research Council (MRC) sum score, motor function with the Hammersmith Functional Motor Scale Expanded (HFMSE) and Motor Function Measure (MFM), NMJ function with repetitive nerve stimulation of the accessory and ulnar nerve, and perceived fatigue with the PROMIS Fatigue Short Form questionnaire in 61 children and adults with SMA types 2-4. We applied Cox regression analysis to explore the associations between fatigability and these factors. The hazard of drop-out on the ESTCS decreased 0.8%, 2%, and 1.3% for each point increase in the MRC sum score, the HFMSE score, and the MFM percentual score, respectively. However, we observed prominent fatigability with preserved muscle function and vice versa in 13%-16% of patients. We did not find an association between NMJ dysfunction of the accessory (p = 0.37) and ulnar nerve (p = 0.063) and fatigability, which could be due to a large number of missing values. Perceived fatigue in SMA was comparable to reference values and was not associated with fatigability (p = 0.52). Fatigability in SMA is associated with, yet not equivalent to, muscle strength and motor function.

Intelligent difficulty scoring and assistance system for endoscopic extraction of common bile duct stones based on deep learning: multicenter study.

The study aimed to construct an intelligent difficulty scoring and assistance system (DSAS) for endoscopic retrograde cholangiopancreatography (ERCP) treatment of common bile duct (CBD) stones. 1954 cholangiograms were collected from three hospitals for training and testing the DSAS. The D-LinkNet34 and U-Net were adopted to segment the CBD, stones, and duodenoscope. Based on the segmentation results, the stone size, distal CBD diameter, distal CBD arm, and distal CBD angulation were estimated. The performance of segmentation and estimation was assessed by mean intersection over union (mIoU) and average relative error. A technical difficulty scoring scale, which was used for assessing the technical difficulty of CBD stone removal, was developed and validated. We also analyzed the relationship between scores evaluated by the DSAS and clinical indicators including stone clearance rate and need for endoscopic papillary large-balloon dilation (EPLBD) and lithotripsy. The mIoU values of the stone, CBD, and duodenoscope segmentation were 68.35 %, 86.42 %, and 95.85 %, respectively. The estimation performance of the DSAS was superior to nonexpert endoscopists. In addition, the technical difficulty scoring performance of the DSAS was more consistent with expert endoscopists than two nonexpert endoscopists. A DSAS assessment score ≥ 2 was correlated with lower stone clearance rates and more frequent EPLBD. An intelligent DSAS based on deep learning was developed. The DSAS could assist endoscopists by automatically scoring the technical difficulty of CBD stone extraction, and guiding the choice of therapeutic approach and appropriate accessories during ERCP.

Objective Evaluation of Proprioceptive Perception of Single-Joint Arm Movements in Patients with Hemiparesis of Central Genesis

Aim. Objective evaluation of proprioceptive perception of single-joint movements of the paretic arm in patients with unilateral brain damage using the method developed by us. Materials and Methods. Proprioceptive perception of pronation-supination of the forearm, flexion-extension in the shoulder, elbow and wrist joints and abduction-adduction in the shoulder and wrist joints was tested in 23 patients with right-sided and 17 patients with left-sided brain damage. The subject with his eyes closed was made to perform a series of passive cyclical test movements, during which he had to copy them with active movements of the other arm. Joint angles were recorded in the test joint and the same joint ofthe other arm. The integrity of proprioceptive sensitivity was judged by the degree of similarity between “active” and “passive” movements estimated by means of objective qualitative and quantitative indicators. Results. Proprioceptive deficiency was detected in 83% of patients with lesion in the right and in 71% of patients with lesion inthe left hemisphere, while the proportion of test movements that revealed a violation of proprioceptive perception was 1.4 times higher in the right-hemisphere patients than in the left-hemisphere patients. A significant part of proprioceptive impairments, – 80% when testing movements of more distal and 29% – proximal segments of the arm, was detected by the presence of qualitative copying errors. Conclusions. The method used made it possible to identify proprioceptive deficits in more than half of patients with damage to both the right and left hemispheres. Proprioceptive perception of movements of the distal arm segment suffered more often and was more pronounced than the proximal one. A significant part of distal segment proprioception disorders manifested themselves in the form of gross qualitative copying errors, which can be detected visually during testing, even without the use of recording equipment.

Gains Across WHO Dimensions of Function After Robot-Based Therapy in Stroke Subjects

Background Studies examining the effects of therapeutic interventions after stroke often focus on changes in loss of body function/structure (impairment). However, improvements in activities limitations and participation restriction are often higher patient priorities, and the relationship that these measures have with loss of body function/structure is unclear. Objective This study measured gains across WHO International Classification of Function (ICF) dimensions and examined their interrelationships. Methods Subjects were recruited 11 to 26 weeks after hemiparetic stroke. Over a 3-week period, subjects received 12 sessions of intensive robot-based therapy targeting the distal arm. Each subject was assessed at baseline and at 1 month after end of therapy. Results At baseline, subjects (n = 40) were 134.7 ± 32.4 (mean ± SD) days poststroke and had moderate-severe arm motor deficits (arm motor Fugl-Meyer score of 35.6 ± 14.4) that were stable. Subjects averaged 2579 thumb movements and 1298 wrist movements per treatment session. After robot therapy, there was significant improvement in measures of body function/structure (Fugl-Meyer score) and activity limitations (Action Research Arm Test, Barthel Index, and Stroke Impact Scale–Hand), but not participation restriction (Stroke Specific Quality of Life Scale). Furthermore, while the degree of improvement in loss of body function/structure was correlated with improvement in activity limitations, neither improvement in loss of body function/structure nor improvement in activity limitations was correlated with change in participation restriction. Conclusions After a 3-week course of robotic therapy, there was improvement in body function/structure and activity limitations but no reduction in participation restriction.

Fraternal twins with Phelan-McDermid syndrome not involving the SHANK3 gene: case report and literature review

BackgroundPhelan-McDermid syndrome (PMS, OMIM#606232), or 22q13 deletion syndrome, is a rare genetic disorder caused by deletion of the distal long arm of chromosome 22 with a variety of clinical features that display considerably heterogeneous degrees of severity. The SHANK3 gene is understood to be the critical gene for the neurological features of this syndrome.Case presentationWe describe one pair of boy-girl twins with a 22q13 deletion not involving the SHANK3 gene. Interestingly, the clinical and molecular findings of the two patients were identical, likely resulting from germline mosaicism in a parent. The boy-girl twins showed intellectual disability, speech absence, facial dysmorphism, cyanosis, large fleshy hands and feet, dysplastic fingernails and abnormal behaviors, and third-generation sequencing showed an identical de novo interstitial deletion of 6.0 Mb in the 22q13.31-q13.33 region.ConclusionsOur case suggests that prenatal diagnosis is essential for normal parents with affected children due to the theoretical possibility of parental germline mosaicism. Our results also indicated that other genes located in the 22q13 region may have a role in explaining symptoms in individuals with PMS. In particular, we propose that four candidate genes, CELSR1, ATXN10, FBLN1 and WNT7B, may also be involved in the etiology of the clinical features of PMS. However, more studies of smaller interstitial deletions with 22q13 are needed to corroborate our hypothesis and better define the genotype-phenotype correlation. Our findings contribute to a more comprehensive understanding of PMS.

Cutaneous nerve-conscious surgical repair of vascular access-related aneurysm assisted by anatomical ultrasonography in hemodialysis patients.

Background:The superficial runoff veins anatomically run alongside the cutaneous nerves in the volar forearm. Consequently, the surgical repair of vascular access (VA)-associated venous aneurysms attached to the cutaneous nerves could cause intraoperative nerve injury. Therefore, we proposed a cutaneous nerve-conscious VA-related aneurysmal repair assisted by nerve ultrasonography. This ultrasonography aids in the preoperative examination of the courses of the nerves neighboring the aneurysm.Methods:Sixteen consecutive patients who underwent surgical revisions of VA-related aneurysms (14 venous aneurysms and two arterial pseudoaneurysms) were enrolled. The locations of aneurysms derived from preexisting arteriovenous fistulas included 11 radiocephalic arteriovenous fistulas in the wrist or distally, three radiocephalic arteriovenous fistulas at the antecubital fossa, and two brachiocephalic arteriovenous fistulas at the antecubital fossa or in the distal upper arm. A preoperative ultrasonographic scan of the cutaneous nerve trunks that ran peripherally toward and along the aneurysms was attempted to avoid nerve injuries during operations. Basically, the aneurysms were resected from the proximal to the distal ends after being separated from the preserved adjacent nerves.Results:The cutaneous nerve trunks that coursed toward and along the aneurysm could be identified by preoperative ultrasonography and could be preserved intraoperatively based on ultrasonographic findings in all patients. In four patients, the cutaneous nerve branch was unexpectedly or intentionally severed for a seamless surgical process because the nerve branch that divided from the cutaneous nerve trunk was strongly attached to the aneurysm. They subsequently suffered from hypoesthesia, but did not experience neuropathic pain.Conclusion:Preoperative ultrasonographic examination of the cutaneous nerve facilitated the intraoperative prevention of cutaneous nerve injury in VA-related aneurysmectomy. Nerve-sparing VA surgery assisted by preoperative nerve ultrasonography based on the understanding of topological anatomy might contribute to the reduction in postoperative neuropathy and enhance comfort in the daily life of hemodialysis patients.

Amyloid Myopathy as an Inclusion Body Myositis Mimic

Introduction: Amyloid myopathy is a rare presentation of systemic amyloidosis. Amyloid myopathy can be initially misdiagnosed as sporadic inclusion body myositis (IBM).
 Methods: We report 4 cases of amyloid myopathy clinically mimicking inclusion body myositis and initially thought to be phenotypically IBM by neuromuscular experts.
 Results: Case 1 is an 81-year-old woman who presented with distal arm and proximal leg asymmetric weakness (myopathy pattern 4). Case 2 is a 76-year-old man with primary systemic amyloidosis who presented with myopathy pattern 4 and progressive dysphagia for four years. Case 3 is an 82-year-old man with progressive myopathy pattern 4 weakness and swallowing difficulty. Case 4 is a 62-year-old man with progressive bilateral finger flexor weakness. Muscle biopsies in all 4 cases showed perivascular amyloid deposits
 Discussion: Amyloid myopathy may be clinically indistinguishable from IBM. Muscle biopsy is of critical importance in the evaluation of patients suspected to have IBM.

Ultrasound-guided supraclavicular vs. retroclavicular block of the brachial plexus: comparison of ipsilateral diaphragmatic function: A randomised clinical trial.

The ultrasound-guided retroclavicular block (RCB) is a recently described alternative approach to brachial plexus blockade at the level of the cords. Although more distal blockade of the brachial plexus is thought to be associated with a lower incidence of phrenic nerve block, the impact of RCB on ipsilateral diaphragmatic function has not been formally investigated. To compare the effects of supraclavicular and retroclavicular brachial plexus block on diaphragmatic function. A single tertiary hospital, study period from December 2017 to May 2019. Double-blinded, randomised study. A total of 40 patients undergoing upper extremity surgery below the axilla. Exclusion criteria included significant pulmonary disease, BMI more than 40 and contra-indication to peripheral nerve block. Patients were randomised to supraclavicular or retroclavicular brachial plexus block with ropivacaine 0.5%. Phrenic block was assessed by measuring changes in diaphragmatic excursion using M-mode ultrasound, and maximum inspiratory volume on incentive spirometry from baseline, at 15 and 30 min postblock, and postoperatively. Comparative assessment of block characteristics included timing and distribution of sensory and motor block onset in the upper extremity, and scanning and block performance times. The incidence of phrenic block in the supraclavicular group was higher by ultrasound imaging (70 vs. 15%) and also by pulmonary function testing (55 vs. 5%), with both diaphragmatic excursion and maximum inspiratory volume decreasing to a greater extent after supraclavicular block (SCB) compared with RCB at 15, 30 min and postoperative time points (repeated measures analysis of variance, P < 0.001). There was no difference in timing and extent of distal arm block, but suprascapular and axillary nerves were more consistently blocked after SCB than after RCB. The current study confirms the hypothesis that a RCB is significantly less likely to affect ipsilateral diaphragmatic function than a SCB. Clinicaltrials.gov identifier: NCT02631122.

Evaluation of the ulnar nerve with shear-wave elastography: a potential sonographic method for the diagnosis of ulnar neuropathy.

PurposeThis study was designed to verify whether shear-wave elastography (SWE) can be used to differentiate ulnar neuropathy at the cubital tunnel from asymptomatic ulnar nerve or medial epicondylitis. An additional aim was to determine a cut-off value to identify patients with ulnar neuropathy.MethodsThis study included 10 patients with ulnar neuropathy at the cubital tunnel as confirmed with electromyography (three women and seven men; mean age, 51.9 years), 10 patients with medial epicondylitis (nine women and one man; mean age, 56.1 years), and 37 patients with asymptomatic ulnar nerve and lateral epicondylitis (21 women and 16 men; mean age, 54.0 years). Each patient underwent SWE of the ulnar nerve at the cubital tunnel, distal upper arm, and proximal forearm.ResultsPatients with ulnar neuropathy at the cubital tunnel exhibited significantly greater mean ulnar nerve stiffness at the cubital tunnel (66.8 kPa) than controls with medial epicondylitis (21.2 kPa, P=0.015) or lateral epicondylitis (33.9 kPa, P=0.040). No significant differences were observed between patients and controls with regard to ulnar nerve stiffness at the distal upper arm or the proximal forearm. A stiffness of 31.0 kPa provided 100% specificity, 80.0% sensitivity, 100% positive predictive value, and 83.3% negative predictive value for the differentiation between ulnar neuropathy and medial epicondylitis.ConclusionCubital tunnel syndrome is associated with a stiffer ulnar nerve than lateral or medial epicondylitis. SWE seems to be a new, reliable, and simple quantitative diagnostic technique to aid in the precise diagnosis of ulnar neuropathy at the cubital tunnel.

Effect of COVID-19 pandemic on the fracture demographics: Data from a tertiary care hospital in Turkey.

The purpose of this study was to evaluate the types and the frequency of fractures, both in the pediatric and adult population during the COVID-19 pandemic and to find out the differences in comparison to the non-pandemic period. Patients who were admitted to the hospital with a new fracture during pandemic period (March 16 to May 22, 2020) were evaluated. Control group consisted of patients with new fractures admitted to the hospital in the same date range in 2018 and 2019. The patients were divided into two groups as ≤16 years old (group 1) and >16 years old (group 2). The evaluation was based on the age and gender of the patients and localization of the fractures. Hospitalized and surgically treated patients were evaluated as well. A total of 1794, 1747, and 670 fractures were observed in 2018, 2019, and 2020, respectively. Mean age of the patients in group 1 was found to have decreased in the pandemic period (p<0.001). The most common fracture sites in the pediatric population were the distal forearm and distal arm, whereas hand, distal forearm, and foot were most common fracture sites in adults, in both pandemic and non-pandemic periods. The proportional increase in femoral and tibial shaft fractures in group 1, and toe, tibial shaft, and metacarpal fractures in group 2 was found to be statistically significantly (p<0.05). In group 1; 6.8%, 7.7%, and 14.6% of the fractures were treated surgically in 2018, 2019, and 2020, respectively (p<0.001). For group 2, these rates were 20.1%, 18.6%, and 18.1%, respectively (p=0.67). There were 48, 29, and 26 open fractures in 2018, 2019 and 2020, respectively (p=0.066). In pandemic period, duration of the hospital stay was significantly shorter for distal humerus and proximal femur fractures (p values= 0.001 and 0.017, respectively). We observed that the frequency of fractures decreased by approximately one-third during the pandemic period compared with that in the non-pandemic period. The mean age of the patients with a fracture in the pediatric group was found to have decreased also. Finger fractures in pediatric patients and metatarsal fractures in adult patients were found to have significantly decreased during the pandemic. Level III, Diagnostic study.

HEREDITARY ENDOCRINE TUMOURS: CURRENT STATE-OF-THE-ART AND RESEARCH OPPORTUNITIES: GPR101, an orphan GPCR with roles in growth and pituitary tumorigenesis.

We recently described X-linked acrogigantism (X-LAG) in sporadic cases of infantile gigantism and a few familial cases of pituitary gigantism in the context of the disorder known as familial isolated pituitary adenomas. X-LAG cases with early onset gigantism (in infants or toddlers) shared copy number gains (CNG) of the distal long arm of chromosome X (Xq26.3). In all patients described to date with Xq26.3 CNG and acro-gigantism, the only coding gene sequence shared by all chromosomal defects was that of GPR101. GPR101 is a class A, rhodopsin-like orphan guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) with no known endogenous ligand. We review what is known about GPR101, specifically its expression profile in human and animal models, the evidence supporting causation of X-LAG and possibly other roles, including its function in growth, puberty and appetite regulation, as well as efforts to identify putative ligands.

Monitoring muscle over three orders of magnitude: Widespread positive allometry among locomotor and body support musculature in the pectoral girdle of varanid lizards (Varanidae).

There is a functional trade-off in the design of skeletal muscle. Muscle strength depends on the number of muscle fibers in parallel, while shortening velocity and operational distance depend on fascicle length, leading to a trade-off between the maximum force a muscle can produce and its ability to change length and contract rapidly. This trade-off becomes even more pronounced as animals increase in size because muscle strength scales with area (length2 ) while body mass scales with volume (length3 ). In order to understand this muscle trade-off and how animals deal with the biomechanical consequences of size, we investigated muscle properties in the pectoral girdle of varanid lizards. Varanids are an ideal group to study the scaling of muscle properties because they retain similar body proportions and posture across five orders of magnitude in body mass and are highly active, terrestrially adapted reptiles. We measured muscle mass, physiological cross-sectional area, fascicle length, proximal and distal tendon lengths, and proximal and distal moment arms for 27 pectoral girdle muscles in 13 individuals across 8 species ranging from 64g to 40kg. Standard and phylogenetically informed reduced major axis regression was used to investigate how muscle architecture properties scale with body size. Allometric growth was widespread for muscle mass (scaling exponent >1), physiological cross-sectional area (scaling exponent >0.66), but not tendon length (scaling exponent >0.33). Positive allometry for muscle mass was universal among muscles responsible for translating the trunk forward and flexing the elbow, and nearly universal among humeral protractors and wrist flexors. Positive allometry for PCSA was also common among trunk translators and humeral protractors, though less so than muscle mass. Positive scaling for fascicle length was not widespread, but common among humeral protractors. A higher proportion of pectoral girdle muscles scaled with positive allometry than our previous work showed for the pelvic girdle, suggesting that the center of mass may move cranially with body size in varanids, or that the pectoral girdle may assume a more dominant role in locomotion in larger species. Scaling exponents for physiological cross-sectional area among muscles primarily associated with propulsion or with a dual role were generally higher than those associated primarily with support against gravity, suggesting that locomotor demands have at least an equal influence on muscle architecture as body support. Overall, these results suggest that larger varanids compensate for the increased biomechanical demands of locomotion and body support at higher body sizes by developing larger pectoral muscles with higher physiological cross-sectional areas. The isometric scaling rates for fascicle length among locomotion-oriented pectoral girdle muscles suggest that larger varanids may be forced to use shorter stride lengths, but this problem may be circumvented by increases in limb excursion afforded by the sliding coracosternal joint.

Characterization and fine mapping of a leaf yellowing mutant in common wheat

Creation of leaf color mutants is the options in the study of photosynthesis, chloroplast development and Chlorophyll biosynthesis. In this study, a leaf color mutant NAU31 was identified from tissue culture of common wheat. In general, the mutant exhibited whole plant yellowing, fewer tillering, dwarfing and interestingly, improved resistance to wheat powdery mildew. Photosynthetic physiological analysis showed that the chloroplast inner structure varied in the mesophyll cells of the mutant, and this may lead to reduced chlorophyll content (chlorophyll “a”, Chlorophyll “b”, total chlorophyll and carotenoid), as well as decreased maximum quantum efficiency of photosystem II (Fv/Fm) and net photosynthetic rate. Transcriptome analysis indicated that the impairing of photosynthesis may be responsible for plant yellowing of NAU31. Inheritance analysis showed that NAU31 was a gain-of-function mutant and the yellowing trait was controlled by a dominant gene, namely Taymg (yellow mutant gene). SSR markers analysis preliminarily mapped Taymg to the distal short arm of chromosome 2D using an F2 population from the cross between NAU31 and W7984, a synthesized wheat. The mapping result was confirmed by BSA using a 55 K wheat SNP array. Through recombinants screening, the Taymg was finely mapped to the terminal region of 2DS, flanked by markers ZH47 and gwm296 and corresponding to a physical interval of 0.76 Mb. The cloning of Taymg will facilitate the dissection of the mechanism involved in chloroplast development of wheat and the coordinating of plant development and disease resistance.

The Branching and Innervation Pattern of the Radial Nerve in the Forearm: Clarifying the Literature and Understanding Variations and Their Clinical Implications.

Background: This study attempted to clarify the innervation pattern of the muscles of the distal arm and posterior forearm through cadaveric dissection. Methods: Thirty-five cadavers were dissected to expose the radial nerve in the forearm. Each muscular branch of the nerve was identified and their length and distance along the nerve were recorded. These values were used to determine the typical branching and motor entry orders. Results: The typical branching order was brachialis, brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, supinator, extensor digitorum, extensor carpi ulnaris, abductor pollicis longus, extensor digiti minimi, extensor pollicis brevis, extensor pollicis longus and extensor indicis. Notably, the radial nerve often innervated brachialis (60%), and its superficial branch often innervated extensor carpi radialis brevis (25.7%). Conclusions: The radial nerve exhibits significant variability in the posterior forearm. However, there is enough consistency to identify an archetypal pattern and order of innervation. These findings may also need to be considered when planning surgical approaches to the distal arm, elbow and proximal forearm to prevent an undue loss of motor function. The review of the literature yielded multiple studies employing inconsistent metrics and terminology to define order or innervation.

Histone H3K9 methylation promotes formation of genome compartments in Caenorhabditis elegans via chromosome compaction and perinuclear anchoring

Genomic regions preferentially associate with regions of similar transcriptional activity, partitioning genomes into active and inactive compartments within the nucleus. Here we explore mechanisms controlling genome compartment organization in Caenorhabditis elegans and investigate roles for compartments in regulating gene expression. Distal arms of C. elegans chromosomes, which are enriched for heterochromatic histone modifications H3K9me1/me2/me3, interact with each other both in cis and in trans, while interacting less frequently with central regions, leading to genome compartmentalization. Arms are anchored to the nuclear periphery via the nuclear envelope protein CEC-4, which binds to H3K9me. By performing genome-wide chromosome conformation capture experiments (Hi-C), we showed that eliminating H3K9me1/me2/me3 through mutations in the methyltransferase genes met-2 and set-25 significantly impaired formation of inactive Arm and active Center compartments. cec-4 mutations also impaired compartmentalization, but to a lesser extent. We found that H3K9me promotes compartmentalization through two distinct mechanisms: Perinuclear anchoring of chromosome arms via CEC-4 to promote their cis association, and an anchoring-independent mechanism that compacts individual chromosome arms. In both met-2 set-25 and cec-4 mutants, no dramatic changes in gene expression were found for genes that switched compartments or for genes that remained in their original compartment, suggesting that compartment strength does not dictate gene-expression levels. Furthermore, H3K9me, but not perinuclear anchoring, also contributes to formation of another prominent feature of chromosome organization, megabase-scale topologically associating domains on X established by the dosage compensation condensin complex. Our results demonstrate that H3K9me plays crucial roles in regulating genome organization at multiple levels.

Carpal tunnel syndrome due to amyloidosis

A 72-year-old man presented to the emergency department with 5-year history of progressive bilateral distal arm weakness. There was bilateral atrophy of the thenar eminences (figure 1) and weakness of...

Increased oxygenation in the non-contracting forearm muscle during contralateral skilful hand movement.

What is the central question of this study? When performing skilful hand movement, motor command descends especially towards distal arm muscles. Does central command evoke a vascular response selectively in the distal arm muscles during skilful hand movement? What is the main finding and its importance? We found, using near-infrared spectroscopy, that unilateral skilful hand movement evoked a greater increase in oxygenation of the contralateral forearm muscle compared with that of the upper arm muscles. Mental imagery of the hand movement also increased oxygenation of the forearm muscle. These findings suggest that central command might contribute to the vasodilator response in the non-contracting forearm muscle during contralateral skilful hand movement. The human hand is a special organ to perform skilful movement in daily life. To meet metabolic demands of the working distal arm muscles, central command might evoke neurogenic vasodilatation in the muscles. Based on our previous demonstration that a centrally generated vasodilator signal is transmitted bilaterally to skeletal muscles during exercise, centrally induced vasodilatation might occur in the non-contracting distal arm muscles during contralateral skilful hand movement. To examine this possibility, we used near-infrared spectroscopy to measure the relative concentrations of oxygenated haemoglobin (Oxy-Hb; as an index of regional blood flow) in the non-contracting arm muscles during skilful hand movement (two-ball rotation) in 22 subjects. Two-ball rotation increased Oxy-Hb of both forearm and upper arm muscles, with little changes in perfusion pressure and cardiac output. The increased Oxy-Hb was greater in the forearm muscle than in the upper arm muscles. The increased Oxy-Hb of the forearm muscle during two-ball rotation was greater than that during one-armed cranking performed with no load. Mental imagery of two-ball rotation increased Oxy-Hb of the forearm and biceps muscles. The increases in Oxy-Hb of both forearm and upper arm muscles during two-ball rotation were reduced by decreasing the level of task difficulty. Intravenous administration of atropine attenuated the increases in Oxy-Hb of the arm muscles during two-ball rotation. It is likely that contralateral skilful hand movement evokes a selective increase in Oxy-Hb of the non-contracting forearm muscle via a sympathetic cholinergic mechanism and that the increase in oxygenation might be mediated, at least in part, by central command.

Heat stress-induced transposon activation correlates with 3D chromatin organization rearrangement in Arabidopsis

In higher eukaryotes, heterochromatin is mainly composed of transposable elements (TEs) silenced by epigenetic mechanisms. But, the silencing of certain heterochromatin-associated TEs is disrupted by heat stress. By comparing genome-wide high-resolution chromatin packing patterns under normal or heat conditions obtained through Hi-C analysis, we show here that heat stress causes global rearrangement of the 3D genome in Arabidopsis thaliana. Contacts between pericentromeric regions and distal chromosome arms, as well as proximal intra-chromosomal interactions along the chromosomes, are enhanced. However, interactions within pericentromeres and those between distal intra-chromosomal regions are decreased. Many inter-chromosomal interactions, including those within the KNOT, are also reduced. Furthermore, heat activation of TEs exhibits a high correlation with the reduction of chromosomal interactions involving pericentromeres, the KNOT, the knob, and the upstream and downstream flanking regions of the activated TEs. Together, our results provide insights into the relationship between TE activation and 3D genome reorganization.

Hip displacement in Wolf-Hirschhorn syndrome: Report on three cases and review of associated musculoskeletal pathologies.

Wolf-Hirschhorn syndrome is a rare genetic disease caused by a chromosomal deletion of the distal short arm of Chromosome 4. It is associated with multisystem abnormalities, including delayed growth, characteristic facial features, epilepsy, and skeletal abnormalities. We report three patients who developed hip displacement, and describe the occurrence of delayed and nonunion in patients who underwent corrective proximal femoral osteotomy for hip displacement. We also performed a literature review identifying common musculoskeletal presentations associated with the condition. Patients with Wolf-Hirschhorn Syndrome are at risk of hip displacement (subluxation), and we would advocate annual hip surveillance in this patient group.