455 research outputs found

    Management and visual outcome of endophthalmitis in Pakistan.

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    Background Many cases of post-operative and posttraumatic endophthalmitis are being managed at the Khyber Institute of Ophthalmic Medical Sciences, Peshawar in Pakistan but no study has been doneto ascertain the magnitude of the disease and to also evaluate the visual outcome after management. Methods The case notes of 39 patients diagnosed with posttraumatic and postoperative endophthalmitis between May 2006 and April 2007 were analyzed and clinical characteristics obtainedwere documented and tabulated Results During the study period, 2474 patients were admitted in both the male and female wards. Ofthese, 39 (1.6%) had endophthalmitis due to surgical and traumatic complications. In all, 6 (12.4%) patients had evisceration, while 21 (53.8%) patients who had topical antibiotics consisting of ofloxacin,0.1% corticosteroids, fortified cetazoline and 1% atropine along with intravitreal antibiotics, a combination of 0.1mg vancomycin and 0.4mg amikacin, were discharged home with a visual acuity of counting fingers to light perception. Conclusion Endophthalmitis is a serious ocular complication of open globe injury and intraocular surgery. The frequency in this center has been noted to be very high as compared to other places. Its management is very challenging and often leads to devastating structural and functional damage to the eye; causing severe frustration to both the patient and the attending physician. Efforts must be made toprevent the condition

    Dental plaque as a biofilm and a microbial community – implications for health and disease

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    Dental plaque is a structurally- and functionally-organized biofilm. Plaque forms in an ordered way and has a diverse microbial composition that, in health, remains relatively stable over time (microbial homeostasis). The predominant species from diseased sites are different from those found in healthy sites, although the putative pathogens can often be detected in low numbers at normal sites. In dental caries, there is a shift toward community dominance by acidogenic and acid-tolerating species such as mutans streptococci and lactobacilli, although other species with relevant traits may be involved. Strategies to control caries could include inhibition of biofilm development (e.g. prevention of attachment of cariogenic bacteria, manipulation of cell signaling mechanisms, delivery of effective antimicrobials, etc.), or enhancement of the host defenses. Additionally, these more conventional approaches could be augmented by interference with the factors that enable the cariogenic bacteria to escape from the normal homeostatic mechanisms that restrict their growth in plaque and out compete the organisms associated with health. Evidence suggests that regular conditions of low pH in plaque select for mutans streptococci and lactobacilli. Therefore, the suppression of sugar catabolism and acid production by the use of metabolic inhibitors and non-fermentable artificial sweeteners in snacks, or the stimulation of saliva flow, could assist in the maintenance of homeostasis in plaque. Arguments will be presented that an appreciation of ecological principles will enable a more holistic approach to be taken in caries control

    Identifying the Origins of Microstructural Defects Such as Cracking within Ni‐Rich NMC811 Cathode Particles for Lithium‐Ion Batteries

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    The next generation of automotive lithium‐ion batteries may employ NMC811 materials; however, defective particles are of significant interest due to their links to performance loss. Here, it is demonstrated that even before operation, on average, one‐third of NMC811 particles experience some form of defect, increasing in severity near the separator interface. It is determined that defective particles can be detected and quantified using low resolution imaging, presenting a significant improvement for material statistics. Fluorescence and diffraction data reveal that the variation of Mn content within the NMC particles may correlate to crystallographic disordering, indicating that the mobility and dissolution of Mn may be a key aspect of degradation during initial cycling. This, however, does not appear to correlate with the severity of particle cracking, which when analyzed at high spatial resolutions, reveals cracking structures similar to lower Ni content NMC, suggesting that the disconnection and separation of neighboring primary particles may be due to electrochemical expansion/contraction, exacerbated by other factors such as grain orientation that are inherent in such polycrystalline materials. These findings can guide research directions toward mitigating degradation at each respective length‐scale: electrode sheets, secondary and primary particles, and individual crystals, ultimately leading to improved automotive ranges and lifetimes

    Bacterial community development in experimental gingivitis.

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    Current knowledge of the microbial composition of dental plaque in early gingivitis is based largely on microscopy and cultural methods, which do not provide a comprehensive description of oral microbial communities. This study used 454-pyrosequencing of the V1-V3 region of 16S rRNA genes (approximately 500 bp), and bacterial culture, to characterize the composition of plaque during the transition from periodontal health to gingivitis. A total of 20 healthy volunteers abstained from oral hygiene for two weeks, allowing plaque to accumulate and gingivitis to develop. Plaque samples were analyzed at baseline, and after one and two weeks. In addition, plaque samples from 20 chronic periodontitis patients were analyzed for cross-sectional comparison to the experimental gingivitis cohort. All of the healthy volunteers developed gingivitis after two weeks. Pyrosequencing yielded a final total of 344,267 sequences after filtering, with a mean length of 354 bases, that were clustered into an average of 299 species-level Operational Taxonomic Units (OTUs) per sample. Principal coordinates analysis (PCoA) plots revealed significant shifts in the bacterial community structure of plaque as gingivitis was induced, and community diversity increased significantly after two weeks. Changes in the relative abundance of OTUs during the transition from health to gingivitis were correlated to bleeding on probing (BoP) scores and resulted in the identification of new health- and gingivitis-associated taxa. Comparison of the healthy volunteers to the periodontitis patients also confirmed the association of a number of putative periodontal pathogens with chronic periodontitis. Taxa associated with gingivitis included Fusobacterium nucleatum subsp. polymorphum, Lachnospiraceae [G-2] sp. HOT100, Lautropia sp. HOTA94, and Prevotella oulorum, whilst Rothia dentocariosa was associated with periodontal health. Further study of these taxa is warranted and may lead to new therapeutic approaches to prevent periodontal disease.BBSRC Industrial Case Studentship ref no. BB/G01714X/1 in collaboration with GlaxoSmithKline

    Ancestral bias in the Hras1 gene and distal Chromosome 7 among inbred mice

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    Inbred strains of mice vary in their frequency of liver tumors initiated by a mutation in the Hras1 (H-ras) proto-oncogene. We sequenced 4.5 kb of the Hras1 gene on distal Chr 7 in a diverse set of 12 commonly used laboratory inbred strains of mice and detected no sequence variation to account for strain-specific differences in Hras1 mutation prevalence. Furthermore, the Hras1 sequence is essentially monoallelic for an ancestral gene derived from the M. m. domesticus species. To determine if the monoallelism and associated low rate of polymorphism are unique to Hras1 or representative of the general chromosomal locale, we extended the sequence analysis to 12 genes in the final 8 Mb of distal Chr 7. A region of at least 2.5 Mb that encompasses several genes, including Hras1 and the H19/Igf2 loci, demonstrates virtually no sequence variation. The 12 inbred strains share one dominant haplotype derived from the M. m. domesticus allele. Chromosomal regions flanking the monoallelic segment exhibit a significantly higher rate of variation and multiple haplotypes, a majority of which are attributed to M. m. domesticus or M. m. musculus ancestry

    Ferritins: furnishing proteins with iron

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    Ferritins are a superfamily of iron oxidation, storage and mineralization proteins found throughout the animal, plant, and microbial kingdoms. The majority of ferritins consist of 24 subunits that individually fold into 4-α-helix bundles and assemble in a highly symmetric manner to form an approximately spherical protein coat around a central cavity into which an iron-containing mineral can be formed. Channels through the coat at inter-subunit contact points facilitate passage of iron ions to and from the central cavity, and intrasubunit catalytic sites, called ferroxidase centers, drive Fe2+ oxidation and O2 reduction. Though the different members of the superfamily share a common structure, there is often little amino acid sequence identity between them. Even where there is a high degree of sequence identity between two ferritins there can be major differences in how the proteins handle iron. In this review we describe some of the important structural features of ferritins and their mineralized iron cores and examine in detail how three selected ferritins oxidise Fe2+ in order to explore the mechanistic variations that exist amongst ferritins. We suggest that the mechanistic differences reflect differing evolutionary pressures on amino acid sequences, and that these differing pressures are a consequence of different primary functions for different ferritins

    Clinical effectiveness and cost-effectiveness of physiotherapy and occupational therapy versus no therapy in mild to moderate Parkinson’s disease: a large pragmatic randomised controlled trial (PD REHAB)

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    Background Cochrane reviews of physiotherapy (PT) and occupational therapy (OT) for Parkinson’s disease found insufficient evidence of effectiveness, but previous trials were methodologically flawed with small sample size and short-term follow-up. Objectives To evaluate the clinical effectiveness and cost-effectiveness of individualised PT and OT in Parkinson’s disease. Design Large pragmatic randomised controlled trial. Setting Thirty-eight neurology and geriatric medicine outpatient clinics in the UK. Participants Seven hundred and sixty-two patients with mild to moderate Parkinson’s disease reporting limitations in activities of daily living (ADL). Intervention Patients were randomised online to either both PT and OT NHS services (n = 381) or no therapy (n = 381). Therapy incorporated a patient-centred approach with individual assessment and goal setting. Main outcome measures The primary outcome was instrumental ADL measured by the patient-completed Nottingham Extended Activities of Daily Living (NEADL) scale at 3 months after randomisation. Secondary outcomes were health-related quality of life [Parkinson’s Disease Questionnaire-39 (PDQ-39); European Quality of Life-5 Dimensions (EQ-5D)], adverse events, resource use and carer quality of life (Short Form questionnaire-12 items). Outcomes were assessed before randomisation and at 3, 9 and 15 months after randomisation. Results Data from 92% of the participants in each group were available at the primary time point of 3 months, but there was no difference in NEADL total score [difference 0.5 points, 95% confidence interval (CI) –0.7 to 1.7; p = 0.4] or PDQ-39 summary index (0.007 points, 95% CI –1.5 to 1.5; p = 1.0) between groups. The EQ-5D quotient was of borderline significance in favour of therapy (–0.03, 95% CI –0.07 to –0.002; p = 0.04). Contact time with therapists was for a median of four visits of 58 minutes each over 8 weeks (mean dose 232 minutes). Repeated measures analysis including all time points showed no difference in NEADL total score, but PDQ-39 summary index (curves diverging at 1.6 points per annum, 95% CI 0.47 to 2.62; p = 0.005) and EQ-5D quotient (0.02, 95% CI 0.00007 to 0.03; p = 0.04) showed significant but small differences in favour of the therapy arm. Cost-effective analysis showed that therapy was associated with a slight but not significant gain in quality-adjusted life-years (0.027, 95% CI –0.010 to 0.065) at a small incremental cost (£164, 95% CI –£141 to £468), resulting in an incremental cost-effectiveness ratio of under £4000 (£3493, 95% –£169,371 to £176,358). There was no difference in adverse events or serious adverse events. Conclusions NHS PT and OT did not produce immediate or long-term clinically meaningful improvements in ADL or quality of life in patients with mild to moderate Parkinson’s disease. This evidence does not support the use of low-dose, patient-centred, goal-directed PT and OT in patients in the early stages of Parkinson’s disease. Future research should include the development and testing of more structured and intensive PT and OT programmes in patients with all stages of Parkinson’s disease

    Bacterial 16S rRNA/rDNA Profiling in the Liquid Phase of Human Saliva

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    Human saliva can be separated by centrifugation into cell pellet and cell-free supernatant, which are called cellular phase and liquid phase in this study. While it is well documented that the cellular phase of saliva contains hundreds of oral bacteria species, little is known whether the liquid phase of saliva contains any information related to oral microbiota. In this study, we analyzed the bacterial nucleic acid contents of the liquid phase of saliva. Using primers universal to most eubacterial 16S rDNA, we detected large amounts of bacterial 16S rRNA and rDNA in the cell-free phase of saliva. Random sequencing analysis of forty PCR amplicons from the cell-free phase of saliva led to 15 operational taxonomic unit (OTU) groups. Furthermore, using denaturing gradient gel electrophoresis (DGGE), we compared 16S rRNA/rDNA profiles derived from liquid phases and cellular phases of saliva samples, and found positive correlations (Pearson Correlation=0.822, P<0.001) between these sample groups. These findings indicate that the liquid phase of saliva contains numerous bacterial 16S rRNA/rDNA molecules that have correlations with bacteria existing in the cellular phase

    Seasonal changes in patterns of gene expression in avian song control brain regions.

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Photoperiod and hormonal cues drive dramatic seasonal changes in structure and function of the avian song control system. Little is known, however, about the patterns of gene expression associated with seasonal changes. Here we address this issue by altering the hormonal and photoperiodic conditions in seasonally-breeding Gambel's white-crowned sparrows and extracting RNA from the telencephalic song control nuclei HVC and RA across multiple time points that capture different stages of growth and regression. We chose HVC and RA because while both nuclei change in volume across seasons, the cellular mechanisms underlying these changes differ. We thus hypothesized that different genes would be expressed between HVC and RA. We tested this by using the extracted RNA to perform a cDNA microarray hybridization developed by the SoNG initiative. We then validated these results using qRT-PCR. We found that 363 genes varied by more than 1.5 fold (>log(2) 0.585) in expression in HVC and/or RA. Supporting our hypothesis, only 59 of these 363 genes were found to vary in both nuclei, while 132 gene expression changes were HVC specific and 172 were RA specific. We then assigned many of these genes to functional categories relevant to the different mechanisms underlying seasonal change in HVC and RA, including neurogenesis, apoptosis, cell growth, dendrite arborization and axonal growth, angiogenesis, endocrinology, growth factors, and electrophysiology. This revealed categorical differences in the kinds of genes regulated in HVC and RA. These results show that different molecular programs underlie seasonal changes in HVC and RA, and that gene expression is time specific across different reproductive conditions. Our results provide insights into the complex molecular pathways that underlie adult neural plasticity

    In Vitro Cultivation of 'Unculturable' Oral Bacteria, Facilitated by Community Culture and Media Supplementation with Siderophores

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    Over a third of oral bacteria are as-yet-uncultivated in-vitro. Siderophores have been previously shown to enable in-vitro growth of previously uncultivated bacteria. The objective of this study was to cultivate novel oral bacteria in siderophore-supplemented culture media. Various compounds with siderophore activity, including pyoverdines-Fe-complex, desferricoprogen and salicylic acid, were found to stimulate the growth of difficult-to-culture strains Prevotella sp. HOT-376 and Fretibacterium fastidiosum. Furthermore, pyrosequencing analysis demonstrated increased proportions of the as-yet-uncultivated phylotypes Dialister sp. HOT-119 and Megasphaera sp. HOT-123 on mixed culture plates supplemented with siderophores. Therefore a culture model was developed, which incorporated 15 μg siderophore (pyoverdines-Fe-complex or desferricoprogen) or 150 μl neat subgingival-plaque suspension into a central well on agar plates that were inoculated with heavily-diluted subgingival-plaque samples from subjects with periodontitis. Colonies showing satellitism were passaged onto fresh plates in co-culture with selected helper strains. Five novel strains, representatives of three previously-uncultivated taxa (Anaerolineae bacterium HOT-439, the first oral taxon from the Chloroflexi phylum to have been cultivated; Bacteroidetes bacterium HOT-365; and Peptostreptococcaceae bacterium HOT-091) were successfully isolated. All novel isolates required helper strains for growth, implying dependence on a biofilm lifestyle. Their characterisation will further our understanding of the human oral microbiome
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