Defective complex I assembly due to C20orf7 mutations as a new cause of Leigh syndrome

Background: Leigh syndrome is an early onset, progressive, neurodegenerative disorder with developmental and motor skills regression. Characteristic magnetic resonance imaging abnormalities consist of focal bilateral lesions in the basal ganglia and/or the brainstem. The main cause is a deficiency in oxidative phosphorylation due to mutations in an mtDNA or nuclear oxidative phosphorylation gene. Methods and results: A consanguineous Moroccan family with Leigh syndrome comprise 11 children, three of which are affected. Marker analysis revealed a homozygous region of 11.5 Mb on chromosome 20, containing 111 genes. Eight possible mitochondrial candidate genes were sequenced. Patients were homozygous for an unclassified variant (p.P193L) in the cardiolipin synthase gene (CRLS1). As this variant was present in 20% of a Moroccan control population and enzyme activity was only reduced to 50%, this could not explain the rare clinical phenotype in our family. Patients were also homozygous for an amino acid substitution (p.L159F) in C20orf7, a new complex I assembly factor. Parents were heterozygous and unaffected sibs heterozygous or homozygous wild type. The mutation affects the predicted S-adenosylmethionine (SAM) dependent methyltransferase domain of C20orf7, possibly involved in methylation of NDUFB3 during the assembly process. Blue native gel electrophoresis showed an altered complex I assembly with only 30-40% of mature complex I present in patients and 70-90% in carriers. Conclusions: A new cause of Leigh syndrome can be a defect in early complex I assembly due to C20orf7 mutations

Clinical and arthroscopic findings in recreationally active patients

<p>Abstract</p> <p>Objective</p> <p>To examine the diagnostic accuracy of standard clinical tests for the shoulder in recreational athletes with activity related pain.</p> <p>Design</p> <p>Cohort study with index test of clinical examination and reference standard of arthroscopy.</p> <p>Setting</p> <p>Sports Medicine clinic in Sheffield, U.K.</p> <p>Participants</p> <p>101 recreational athletes (82 male, 19 female; mean age 40.8 ± 14.6 years) over a six year period.</p> <p>Interventions</p> <p>Bilateral evaluation of movements of the shoulder followed by standardized shoulder tests, formulation of clinical diagnosis and shoulder arthroscopy conducted by the same surgeon.</p> <p>Main Outcome Measurements</p> <p>Sensitivity, specificity, likelihood ratio for a positive test and over-all accuracy of clinical examination was examined retrospectively and compared with arthroscopy.</p> <p>Results</p> <p>Isolated pathology was rare, most patients (72%) having more than one injury recorded. O'Brien's clinical test had a mediocre sensitivity (64%) and over-all accuracy (54%) for diagnosing SLAP lesions. Hawkins test and Jobe's test had the highest but still not impressive over-all accuracy (67%) and sensitivity (67%) for rotator cuff pathology respectively. External and internal impingement tests showed similar levels of accuracy. When a positive test was observed in one of a combination of shoulder tests used for diagnosing SLAP lesions or rotator cuff disease, sensitivity increased substantially whilst specificity decreased.</p> <p>Conclusions</p> <p>The diagnostic accuracy of isolated standard shoulder tests in recreational athletes was over-all very poor, potentially due to the majority of athletes (71%) having concomitant shoulder injuries. Most likely, this means that many of these injuries are missed in general practice and treatment is therefore delayed. Clinical examination of the shoulder should involve a combination of clinical tests in order to identify likely intra articular pathology which may warrant referral to specialist for surgery.</p

High frequency of Polio-like Enterovirus C strains with differential clustering of CVA-13 and EV-C99 subgenotypes in a cohort of Malawian children

Enteroviruses (EVs) are among the most commonly detected viruses infecting humans worldwide. Although the prevalence of EVs is widely studied, the status of EV prevalence in sub-Saharan Africa remains largely unknown. The objective of our present study was therefore to increase our knowledge on EV circulation in sub-Saharan Africa. We obtained 749 fecal samples from a cross-sectional study conducted on Malawian children aged 6 to 60 months. We tested the samples for the presence of EVs using real time PCR, and typed the positive samples based on partial viral protein 1 (VP1) sequences. A large proportion of th

Proteome Sampling by the HLA Class I Antigen Processing Pathway

The peptide repertoire that is presented by the set of HLA class I molecules of an individual is formed by the different players of the antigen processing pathway and the stringent binding environment of the HLA class I molecules. Peptide elution studies have shown that only a subset of the human proteome is sampled by the antigen processing machinery and represented on the cell surface. In our study, we quantified the role of each factor relevant in shaping the HLA class I peptide repertoire by combining peptide elution data, in silico predictions of antigen processing and presentation, and data on gene expression and protein abundance. Our results indicate that gene expression level, protein abundance, and rate of potential binding peptides per protein have a clear impact on sampling probability. Furthermore, once a protein is available for the antigen processing machinery in sufficient amounts, C-terminal processing efficiency and binding affinity to the HLA class I molecule determine the identity of the presented peptides. Having studied the impact of each of these factors separately, we subsequently combined all factors in a logistic regression model in order to quantify their relative impact. This model demonstrated the superiority of protein abundance over gene expression level in predicting sampling probability. Being able to discriminate between sampled and non-sampled proteins to a significant degree, our approach can potentially be used to predict the sampling probability of self proteins and of pathogen-derived proteins, which is of importance for the identification of autoimmune antigens and vaccination targets

Anemia and growth failure among HIV-infected children in India: a retrospective analysis

<p>Abstract</p> <p>Background</p> <p>Anemia and poor nutrition have been previously described as independent risk factors for death among HIV-infected children. We sought to describe nutritional status, anemia burden and HIV disease correlates among infected children in India.</p> <p>Methods</p> <p>We analyzed retrospective data from 248 HIV-infected children aged 1–12 years attending three outpatient clinics in South India (2004–2006). Standard WHO definitions were used for anemia, HIV staging and growth parameters. Statistical analysis included chi square, t tests, univariate and multivariate logistic regression analyses.</p> <p>Results</p> <p>The overall prevalence of anemia (defined as hemoglobin < 11 gm/dL) was 66%, and 8% had severe anemia (Hb < 7 gm/dL). The proportion of underweight and stunted children in the population was 55% and 46% respectively. Independent risk factors of anemia by multivariate analysis included the pre-school age group (age younger than 6 years) (OR: 2.87; 95% CI: 1.45, 5.70; p < 0.01), rural residence (OR: 12.04; 95% CI: 5.64, 26.00; p < 0.01), advanced HIV disease stage (OR: 6.95; 95% CI: 3.06, 15.79; p < 0.01) and presence of stunting (Height-for-age Z Score < -2) (OR: 3.24; 95% CI: 1.65, 6.35; p < 0.01). Use of iron/multivitamin supplementation was protective against risk of anemia (OR: 0.44; 95% CI: 0.22, 0.90; p = 0.03). Pulmonary tuberculosis was an independent risk factor in multivariate analysis (OR: 3.36; 95% CI: 1.43, 7.89; p < 0.01) when correlated variables such as HIV disease stage and severe immunodeficiency, and nutritional supplement use were not included. Use of antiretroviral therapy (ART) was associated with a reduced risk of anemia (OR: 0.29; 95% CI: 0.16, 0.53; p < 0.01). No significant association was found between anemia and gender, cotrimoxazole, or ART type (zidovudine versus stavudine).</p> <p>Conclusion</p> <p>The high prevalence and strong interrelationship of anemia and poor nutrition among HIV-infected children in India, particularly those living in rural areas underscores the need for incorporating targeted nutritional interventions during national scale up of care, support and treatment among HIV-infected children.</p

Psychosocial aspects of feeding children with neurodisability

The psychosocial support needs of parents considering a gastrostomy feeding tube for their disabled child are often overlooked, yet there is a growing body of evidence that attests to the decisional conflicts parents, often mothers, experience. This may be in addition to the stress associated with feeding a disabled child. The support needs of families and caregivers should be assessed, including the values parents attach to oral and tube feeding. Structured support should be embedded within the care pathway and both professionals, and service users, with appropriate training should be identified to ensure parental information needs, and any emotional, practical and financial issues are addressed

A community based field research project investigating anaemia amongst young children living in rural Karnataka, India: a cross sectional study

<p>Abstract</p> <p>Background</p> <p>Anaemia is an important problem amongst young children living in rural India. However, there has not previously been a detailed study of the biological aetiology of this anaemia, exploring the relative contributions of iron, vitamin B12, folate and Vitamin A deficiency, inflammation, genetic haemoglobinopathy, hookworm and malaria. Nor have studies related these aetiologic biological factors to household food security, standard of living and child feeding practices. Barriers to conducting such work have included perceived reluctance of village communities to permit their children to undergo venipuncture, and logistical issues. We have successfully completed a community based, cross sectional field study exploring in detail the causes of anaemia amongst young children in a rural setting.</p> <p>Methods and design</p> <p>A cross sectional, community based study. We engaged in extensive community consultation and tailored our study design to the outcomes of these discussions. We utilised local women as field workers, harnessing the capacity of local health workers to assist with the study. We adopted a programmatic approach with a census rather than random sampling strategy in the village, incorporating appropriate case management for children identified to have anaemia. We developed a questionnaire based on existing standard measurement tools for standard of living, food security and nutrition. Specimen processing was conducted at the Primary Health Centre laboratory prior to transport to an urban research laboratory.</p> <p>Discussion</p> <p>Adopting this study design, we have recruited 415 of 470 potentially eligible children who were living in the selected villages. We achieved support from the community and cooperation of local health workers. Our results will improve the understanding into anaemia amongst young children in rural India. However, many further studies are required to understand the health problems of the population of rural India, and our study design and technique provide a useful demonstration of a successful strategy.</p

Rapid Probing of Biological Surfaces with a Sparse-Matrix Peptide Library

Finding unique peptides to target specific biological surfaces is crucial to basic research and technology development, though methods based on biological arrays or large libraries limit the speed and ease with which these necessary compounds can be found. We reasoned that because biological surfaces, such as cell surfaces, mineralized tissues, and various extracellular matrices have unique molecular compositions, they present unique physicochemical signatures to the surrounding medium which could be probed by peptides with appropriately corresponding physicochemical properties. To test this hypothesis, a naïve pilot library of 36 peptides, varying in their hydrophobicity and charge, was arranged in a two-dimensional matrix and screened against various biological surfaces. While the number of peptides in the matrix library was very small, we obtained “hits” against all biological surfaces probed. Sequence refinement of the “hits” led to peptides with markedly higher specificity and binding activity against screened biological surfaces. Genetic studies revealed that peptide binding to bacteria was mediated, at least in some cases, by specific cell-surface molecules, while examination of human tooth sections showed that this method can be used to derive peptides with highly specific binding to human tissue

Controlled Release of Octreotide and Assessment of Peptide Acylation from Poly(D,L-lactide-co-hydroxymethyl glycolide) Compared to PLGA Microspheres

# The Author(s) 2011. This article is published with open access at Springerlink.com Purpose To investigate the in vitro release of octreotide acetate, a somatostatin agonist, from microspheres based on a hydrophilic polyester, poly(D,L-lactide-co-hydroxymethyl glycolide) (PLHMGA). Methods Spherical and non-porous octreotide-loaded PLHMGA microspheres (12 to 16 μm) and loading efficiency of 60–70% were prepared by a solvent evaporation. Octreotide release profiles were compared with commercial PLGA formulation (Sandostatin LAR ®); possible peptide modification with lactic, glycolic and hydroxymethyl glycolic acid units was monitored. Results PLHMGA microspheres showed burst release (~20%) followed by sustained release for 20–60 days, depending on the hydrophilicity of the polymer. Percentage of released loaded peptide was high (70–90%);&gt;60 % of released peptide was native octreotide. PLGA microspheres did not show peptide release for the first 10 days, after which it was released in a sustained manner over the next 90 days;&gt;75 % of released peptides were acylated adducts. Conclusions PLHMGA microspheres are promising controlled systems for peptides with excellent control over release kinetics. Moreover, substantially less peptide modification occurred in PLHMGA than in PLGA microspheres. KEY WORDS acylation. aliphatic polyester. controlle