How much of the effect of exercise and advice for subacute low back pain is mediated by depressive symptoms?

BACKGROUND

Exercise and advice can reduce pain and disability in patients with subacute low back pain. However, the mechanisms by which this combined intervention works are unclear. Our objective was to estimate how much of the effect of a physiotherapist-directed exercise and advice intervention on pain and disability is mediated via changes in depressive symptoms.

METHODS

Causal mediation analysis of a randomized controlled trial. We measured our hypothesized mediator - depressive symptoms (Depression, Anxiety, Stress Scale-21) at 6 weeks, and the outcomes - pain (numerical rating scale) and disability (Roland Morris Disability Questionnaire) at 3 months, estimating the average causal mediation effect (ACME), average direct effect (ADE), and total effect. We pre-specified a causal model to identify potential confounders of the mediator-outcome effect and conducted sensitivity analyses to assess the robustness of the ACME under varying levels of unknown confounding.

RESULTS

Data from 240 patients were analyzed (average age 50.5 (SD 15.6) years, 52% male, median depressive symptoms score 4). The effect of exercise combined with advice was not mediated via depressive symptoms: ACME on pain (0.05, 95%CI -0.24 to 0.15), ACME on disability (-0.10, 95%CI -0.59 to 0.38). However depressive symptoms were associated with pain (regression coefficient 0.06; SE 0.03)) and disability (regression coefficient 0.17; SE 0.05).) CONCLUSIONS: Depressive symptoms did not mediate the effect of exercise and/or advice in this sample. However, depressive symptoms were associated with pain and disability.

Evaluation of neodymium isotope analysis of human dental enamel as a provenance indicator using 1013 Ω amplifiers (TIMS)

Human provenance studies employing isotopic analysis have become an essential tool in forensic and archaeological sciences, with multi-isotope approaches providing more specific location estimates compared to single isotope studies. This study reports on the human provenancing capability of neodymium isotopes (¹⁴³Nd/¹⁴⁴Nd), a relatively conservative tracer in the environment. Neodymium isotope ratios have only recently been determined on human remains due to low concentrations in human dental enamel (ppb range), requiring thermal ionisation mass spectrometry (TIMS) using 10¹³ Ω resistors. Dental elements (third molars) from 20 individuals born and raised in the Netherlands were analysed for Nd concentration (n = 12) and Nd isotope ratios (n = 15). The geological control on Nd isotope composition was examined using coupled Nd-Sr isotope analysis of the same third molar. Teeth from different geological environments were also analysed (Caribbean, Columbian, and Icelandic, n = 5). Neodymium elemental concentrations in dental elements ranged between 0.1 and 7.9 ppb (median 0.5 ppb). The Dutch ¹⁴³Nd/¹⁴⁴Nd ratios of the provinces of Limburg and Friesland were between 0.5118 and 0.5121, with Dutch ⁸⁷Sr/⁸⁶Sr ratios in agreement with the previously established local range (0.708–0.710). The current findings were compared to previously published results on Nd concentration and composition from Dutch individuals. The concentration of Nd and ¹⁴³Nd/¹⁴⁴Nd ratios were weakly correlated (R² = 0.47, n = 17) in Dutch human dental enamel. The majority (n = 25, 83.3%) of individuals had Nd and Sr isotope values isotopically indistinguishable from the geological environment in which their third molars formed and mineralised. However, the Nd isotope ratios of the Icelandic individual and several Dutch individuals (n = 4) suggested that Nd in enamel is not solely influenced by geological environment. In order for neodymium isotopes to be quantitatively applied in forensic and archaeological settings further analyses of individuals from various geographical regions with well-defined dietary Nd isotope data are required.

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First evaluation of the potential of neodymium isotopes for human provenancing

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Provides insight in Nd concentration and isotope ratios in human dental enamel

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First study presenting Nd isotope ratios from multiple geological settings

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First study combining ¹⁴³Nd/¹⁴⁴Nd and ⁸⁷Sr/⁸⁶Sr ratios of the same dental element

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The use of 10¹³ Ω resistors allows for greater precision analysis of small samples

Parents' actions, challenges, and needs while enabling participation of children with a physical disability: a scoping review

Background

Pediatric rehabilitation considers Family-centered service (FCS) as a way to increase participation of children with a physical disability in daily life. An important principal is that parents greatly contribute to their child’s participation at school, at home, and in the community. However, it is unclear what kind of information is available from literature about what parents actually do to support their child’s participation and what problems and needs they experience? Hence, the aim of this study was to provide an overview of the actions, challenges, and needs of parents in enabling participation of their child with a physical disability that is neurological and non-progressive in nature.

Methods

Scoping review with extensive literature search (September 2011) and a thematic analysis to synthesize findings.

Results

Fourteen relevant articles revealed two major themes: ‘parents enable and support performance of meaningful activities’ and ‘parents enable, change and use the environment’. Each theme holds a number of actions (e.g. choosing the right type of meaningful activities for facilitating social contacts) and challenges (e.g. negative attitudes of other people). Less information is available about the needs of parents.

Conclusions

This study indicates that parents apply a broad range of strategies to support participation of their children. They experience many challenges, especially as a result of constraints in the social and physical environments. However, this review also shows that little is known about needs of parents in facilitating participation. As Family-centered service (FCS) philosophy is all about the needs of the child and the family, it is essential to further investigate the needs of the parents and to understand if and to what extent they wish to be supported in enabling their child’s participation in daily life.

Combined enzymatic complex I and III deficiency associated with mutations in the nuclear encoded NDUFS4 gene

Combined OXPHOS-system enzyme deficiencies are observed in approximately 25% of all OXPHOS-system disturbances. Of these, combined complex I and III deficiency is relatively scarce. So far, only mtDNA and thymidine phosphorylase (TP) mutations have been associated with combined OXPHOS-system disturbances. In this report we show, for the first time, that a nuclear gene mutation in a structural, nuclear encoded complex I gene is associated with combined complex I and III deficiency. After our initial report we describe mutations in the NDUFS4 gene of complex I in two additional patients. The first mutation is a deletion of G at position 289 or 290. Amino acid 96 changes from a tryptophan to a stop codon. The mutation was found homozygous in the patient; both parents are heterozygous for the mutation. The second mutation is a transition from C to T at cDNA position 316. Codon is changed from CGA (arginine) to TGA (stop). The patient is homozygous for the mutation; both parents are heterozygous. Both mutations in the NDUFS4 gene led to a premature stop in Leigh-like patients with an early lethal phenotype. We hypothesise that the structural integrity of the OXPHOS system, in mammal supermolecular structures, may be responsible for the observed biochemical features.

A device to facilitate donning and cleaning of a roll-on socket in a trans-tibial amputee with a non-functional arm

Rehabilitation of a person with a non-functional arm and a trans-tibial amputation with a short stump with fragile skin, multiple scars and a limited knee function presents a considerable problem. The best prosthesis was considered to be one with a roll-on socket. Donning and cleaning of the socket however could not be done by the patient himself and it was therefore necessary to develop a device to permit the patient to perform these tasks independently. A case history is presented and the new device described.

Leigh syndrome associated with a mutation in the NDUFS7 (PSST) nuclear encoded subunit of complex I

Leigh syndrome is the phenotypical expression of a genetically heterogeneous cluster of disorders, with pyruvate dehydrogenase complex deficiency and respiratory chain disorders as the main biochemical causes. We report the first missense mutation within the nuclear encoded complex I subunit, NDUFS7, in 2 siblings with neuropathologically proven complex I-deficient Leigh syndrome.

cDNA of eight nuclear encoded subunits of NADH:ubiquinone oxidoreductase: human complex I cDNA characterization completed

NADH:ubiquinone oxidoreductase (complex I) is an extremely complicated multiprotein complex located in the inner mitochondrial membrane. Its main function is the transport of electrons from NADH to ubiquinone, which is accompanied by translocation of protons from the mitochondrial matrix to the intermembrane space. Human complex I appears to consist of 41 subunits of which 34 are encoded by nDNA. Here we report the cDNA sequences of the hitherto uncharacterized 8 nuclear encoded subunits, all located within the hydrophobic protein (HP) fraction of complex I. Now all currently known 41 proteins of human NADH:ubiquinone oxidoreductase have been characterized and reported in literature, which enables more complete mutational analysis studies of isolated complex I-deficient patients.

Nuclear genes of human complex I of the mitochondrial electron transport chain: state of the art

The mitochondrial electron transport chain (mtETC) consists of four multi-subunit enzyme complexes. Complex I or NADH:ubiquinone oxidoreductase, the largest mtETC multisubunit complex, consists of approximately 41 subunits. Seven of these subunits are encoded by the mitochondrial genome, the remainder by the nuclear genome. Among the mitochondriocytopathies, complex I deficiencies are encountered frequently. Although some complex I deficiencies have been associated with mitochondrial DNA mutations, the genetic defect has not been elucidated in the majority of complex I-deficient patients. It is expected that many of these patients have mutations in the nuclear-encoded subunits of this complex, so vital for cellular energy production. After a brief summary of the current knowledge of complex I from cow, bacteria and fungi, this review presents the state of the art of the knowledge of the human nuclear-encoded complex I genes which, in the last 18 months, has made enormous progress. At present, the complete gene structure of four subunits and the cDNA structure of 18 of the 34 complex I nuclear-encoded subunits are known. Mapping of these subunits shows a random distribution over the chromosomes. The chromosomal localization is known for 14 complex I genes. Recently, the first mutation, a 5 bp duplication in the 18 kDa (AQDQ) subunit, has been reported. We expect that within 1 year all human nuclear-encoded complex I subunits will be cloned. Mutational analysis of these subunits is warranted in complex I-deficient patients and will not only be important for genetic counselling but will also extend the knowledge regarding the functional properties of the individual human complex I subunits.