Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Overcoming pain thresholds with multilevel models : an example using quantitative sensory testing (QST) data

The assessment of somatosensory function is a cornerstone of research and clinical practice in neurology. Recent initiatives have developed novel protocols for quantitative sensory testing (QST). Application of these methods led to intriguing findings, such as the presence lower pain-thresholds in healthy children compared to healthy adolescents. In this article, we (re-) introduce the basic concepts of signal detection theory (SDT) as a method to investigate such differences in somatosensory function in detail. SDT describes participants’ responses according to two parameters, sensitivity and response-bias. Sensitivity refers to individuals’ ability to discriminate between painful and non-painful stimulations. Response-bias refers to individuals’ criterion for giving a “painful” response. We describe how multilevel models can be used to estimate these parameters and to overcome central critiques of these methods. To provide an example we apply these methods to data from the mechanical pain sensitivity test of the QST protocol. The results show that adolescents are more sensitive to mechanical pain and contradict the idea that younger children simply use more lenient criteria to report pain. Overall, we hope that the wider use of multilevel modeling to describe somatosensory functioning may advance neurology research and practice

Small-fiber neuropathy and pain sensitization in survivors of pediatric acute lymphoblastic leukemia

Background: Chemotherapy-induced Peripheral Neuropathy (CIPN) of large-fibers affects up to 20% of survivors of pediatric acute lymphoblastic leukemia (ALL). We aimed to describe small-fiber toxicity and pain sensitization in this group. Methods: In a cross-sectional, bicentric study we assessed 46 survivors of pediatric ALL (Mean age: 5.7 ± 3.5 years at diagnosis, median 2.5 years after therapy; males: 28). Inclusion criteria: ≥6 years of age, ≥3 months after last administration of Vincristine, and cumulative dose of Vincristine 12 mg/m2. We used a reduced version of the Pediatric-modified Total Neuropathy Score (Ped-mTNS) as bedside test and Quantitative Sensory Testing (QST) for assessment of small- and large-fiber neuropathy as well as pain sensitization. We employed Nerve Conduction Studies (NCS) as the most accurate tool for detecting large-fiber neuropathy. Results: Fifteen survivors (33%) had abnormal rPed-mTNS values (≥4 points) and 5 survivors (11%) reported pain. In QST, the survivor group showed significant (p < 0.001) inferior large-fiber function and pain sensitization when compared to healthy matched peers. We identified deficits of vibration in 33 (72%) and tactile hypoesthesia in 29 (63%), hyperalgesia to blunt pressure in 19 (41%), increased mechanical pain sensitivity in 12 (26%) and allodynia in 16 (35%) of 46 survivors. Only 7 survivors (15%) had pathologic NCS. Conclusion: QST is a sensitive tool that revealed signs of large-fiber neuropathy in two thirds, small-fiber neuropathy and pain sensitization in one third of survivors. Prospective studies using QST in pediatric oncology may help to elucidate the pathophysiology of small-fiber neuropathy and pain sensitization as well as their relevance for quality of survival

Quantitative sensory testing profiles in children, adolescents and young adults (6–20 years) with cerebral palsy : Hints for a neuropathic genesis of pain syndromes

Introduction: Many patients with cerebral palsy (CP) suffer chronic pain as one of the most limiting factors in their quality of life. In CP patients, pain mechanisms are not well understood, and pain therapy remains a challenge. Quantitative sensory testing (QST) might provide unique information about the functional status of the somatosensory system and therefore better guide pain treatment. Objectives: To understand better the underlying pain mechanisms in pediatric CP patients, we aimed to assess clinical and pain parameters, as well as QST profiles, which were matched to the patients' cerebral imaging pathology. Patients and methods: Thirty CP patients aged 6–20 years old (mean age 12 years) without intellectual impairment underwent standardized assessments of QST. Cerebral imaging was reassessed. QST results were compared to age- and sex-matched controls (multiple linear regression; Fisher's exact test; linear correlation analysis). Results: CP patients were less sensitive to all mechanical and thermal stimuli than healthy controls but more sensitive to all mechanical pain stimuli (each p < 0.001). Fifty percent of CP patients showed a combination of mechanical hypoesthesia, thermal hypoesthesia and mechanical hyperalgesia; 67% of CP patients had periventricular leukomalacia (PVL), which was correlated with mechanic (r = 0.661; p < 0.001) and thermal (r = 0.624; p = 0.001) hypoesthesia. Conclusion: The combination of mechanical hypoesthesia, thermal hypoesthesia and mechanical hyperalgesia in our CP patients implicates lemniscal and extralemniscal neuron dysfunction in the thalamus region, likely due to PVL. We suspect that extralemniscal tracts are involved in the original of pain in our CP patients, as in adults

The development and psychometric assessment of a questionnaire to assess sleep and daily troubles in parents of children and young adults with severe psychomotor impairment

Background: Children with severe psychomotor impairment (SPMI) often experience sleep disturbances that severely distress both the child and his or her parents. Validated questionnaires for the assessment of parents’ distress related to their child’s sleep disturbances are lacking. Methods: We developed and validated a new questionnaire, the HOST (holistic assessment of sleep and daily troubles in parents of children with SPMI) to assess the effect of the sleep disturbances in children with SPMI on their parents. The questionnaire was developed based on published data and expert opinion, and it was refined via direct consultation with affected parents. Its psychometric characteristics were assessed in a sample of parents of 214 children with SPMI. It was retested using a random subsample of the participants. Results: Explorative factor analysis revealed that the HOST was composed of four scales. Fit indices, item analysis, and convergent validity (coherence with preexisting instruments of sleep disturbances and health status) were adequate. Retest analysis (n = 62) revealed high stability of the HOST questionnaire and adequate replication validity. Conclusion: Sleep-related difficulties significantly impact the sociomedical characteristics of the parents of children with complex neurologic diseases. Typically, parents are severely affected in various aspects of daily life (i.e., medical health, social life, professional life). The HOST proved to be a valid, reliable and economical assessment tool of sleep-related difficulties in parents and relatives of children with SPMI. The HOST is capable of identifying individuals and specific areas requiring intervention

Difficulties in screening for peripheral neuropathies in children with diabetes

Aims: To assess the diagnostic utility of a novel abbreviated monofilament test in comparison with the tuning fork test to detect diabetic peripheral neuropathy in children. Methods: A total of 88 children with Type 1 diabetes mellitus were screened for diabetic peripheral neuropathy using the monofilament test and the tuning fork. Nerve conduction studies were performed according to the ‘gold standard’ for neuropathy. We assessed the diagnostic utility and inter-rater agreement of the two screening methods. Results: A total of 43 (49%) children (aged 6–18 years) had at least one abnormal nerve conduction study result. Diagnostic utility and inter-rater agreement were very low for both screening methods. The monofilament test yielded a sensitivity of 18% and a specificity of 80%. The tuning fork yielded a sensitivity of 0% and a specificity of 98%. Conclusion: The present study found that an abbreviated monofilament test has low diagnostic utility for the detection of early diabetic peripheral neuropathy because of its low reliability. The problem of reliability needs to be more thoroughly addressed in order to improve the screening procedures in diabetes management in childhood and adolescence

Towards bio-based tapered block copolymers: the behaviour of myrcene in the statistical anionic copolymerisation

To explore the potential of myrcene (Myr) as a bio-based monoterpene comonomer for styrenic copolymers and to establish its general applicability for the carbanionic copolymerisation, several statistical copolymerisations of myrcene and common monomers like isoprene (I), styrene (S) and 4 methylstyrene (4MS) were carried out in cyclohexane and monitored by in situ 1H NMR spectroscopy. Real-time NMR kinetic studies permitted the determination of the reactivity ratios and the composition profile for each monomer combination. While the copolymerisation of Myr/I yielded a gradient copolymer and reactivity ratios of moderate disparity (rMyr = 4.4; rI = 0.23), the statistical copolymerisation of Myr/S and Myr/4MS afforded block-like, tapered copolymers due to highly diverging reactivity ratios (rMyr = 36; rS = 0.028 and rMyr = 140; r4MS = 0.0074). Furthermore, a terpolymerisation of Myr/I/4MS was studied by real-time NMR kinetics, revealing an alteration of the composition profile of 4MS towards a more block-like structure. Based on the kinetic studies, a series of Myr/I/4MS terpolymers and Myr/S copolymers was prepared by statistical living anionic copolymerisation. All copolymers showed narrow molecular weight distributions (SEC) and two glass transition temperatures (Tg,1 = -51 to¬ 62 °C; Tg,2 = 93 ¬to 107 °C), suggesting phase segregation. TEM and SAXS measurements revealed highly ordered lamellar morphologies for all copolymers with long range correlation and confirmed the block-like structure and behaviour of Myr/S and Myr/4MS copolymers prepared by statistical carbanionic copolymerisation

A Massive Expansion of Effector Genes Underlies Gall-Formation in the Wheat Pest Mayetiola destructor

Gall-forming arthropods are highly specialized herbivores that, in combination with their hosts, produce extended phenotypes with unique morphologies [1]. Many are economically important, and others have improved our understanding of ecology and adaptive radiation [2]. However, the mechanisms that these arthropods use to induce plant galls are poorly understood. We sequenced the genome of the Hessian fly (Mayetiola destructor; Diptera: Cecidomyiidae), a plant parasitic gall midge and a pest of wheat (Triticum spp.), with the aim of identifying genic modifications that contribute to its plant-parasitic lifestyle. Among several adaptive modifications, we discovered an expansive reservoir of potential effector proteins. Nearly 5% of the 20,163 predicted gene models matched putative effector gene transcripts present in the M. destructor larval salivary gland. Another 466 putative effectors were discovered among the genes that have no sequence similarities in other organisms. The largest known arthropod gene family (family SSGP-71) was also discovered within the effector reservoir. SSGP-71 proteins lack sequence homologies to other proteins, but their structures resemble both ubiquitin E3 ligases in plants and E3-ligase-mimicking effectors in plant pathogenic bacteria. SSGP-71 proteins and wheat Skp proteins interact in vivo. Mutations in different SSGP-71 genes avoid the effector-triggered immunity that is directed by the wheat resistance genes H6 and H9. Results point to effectors as the agents responsible for arthropod-induced plant gall formation