Health professionals and students encounter multi-level barriers to implementing high-value osteoarthritis care: a multi-national study.

OBJECTIVE: Consistent evidence-practice gaps in osteoarthritis (OA) care are observed in primary care settings globally. Building workforce capacity to deliver high-value care requires a contemporary understanding of barriers to care delivery. We aimed to explore barriers to OA care delivery among clinicians and students. DESIGN: A cross-sectional, multinational study sampling clinicians (physiotherapists, primary care nurses, general practitioners (GPs), GP registrars; total possible denominator: n = 119,735) and final-year physiotherapy and medical students (denominator: n = 2,215) across Australia, New Zealand and Canada. Respondents answered a survey, aligned to contemporary implementation science domains, which measured barriers to OA care using categorical and free-text responses. RESULTS: 1886 clinicians and 1611 students responded. Items within the domains 'health system' and 'patient-related factors' represented the most applicable barriers experienced by clinicians (25-42% and 20-36%, respectively), whereas for students, 'knowledge and skills' and 'patient-related factors' (16-24% and 19-28%, respectively) were the most applicable domains. Meta-synthesis of qualitative data highlighted skills gaps in specific components of OA care (tailoring exercise, nutritional/overweight management and supporting positive behaviour change); assessment, measurement and monitoring; tailoring care; managing case complexity; and translating knowledge to practice (especially among students). Other barriers included general infrastructure limitations (particularly related to community facilities); patient-related factors (e.g., beliefs and compliance); workforce-related factors such as inconsistent care and a general knowledge gap in high-value care; and system and service-level factors relating to financing and time pressures, respectively. CONCLUSIONS: Clinicians and students encounter barriers to delivery of high-value OA care in clinical practice/training (micro-level); within service environments (meso-level); and within the health system (macro-level).

Psychological status in female carriers of premutation FMR1 allele showing a complex relationship with the size of CGG expansion.

We utilized a sample of 299 adult females aged between 19 and 86 years, carrying fragile X mental retardation (FMR1) alleles with small CCG expansions ranging from 50 to 141 repeats to analyse the relationships between psychological symptoms as assessed by the Symptom Checklist-90-Revised (SCL-90-R) and the size of the CGG repeat in the FMR1 gene. There were highly significant (negative) correlations between the size of the CGG repeat and a great majority of SCL-90-R subscale scores and all the global indices, suggesting that carriers of premutations in the mid-size CGG repeat range may be at greatest risk for the development of psychiatric disorder.

New evidence for, and challenges in, linking small CGG repeat expansion FMR1 alleles with Parkinson's disease.

We recently reported a significant increase in the frequency of carriers of grey zone (GZ) alleles of FMR1 gene in Australian males with Parkinson's disease (PD) from Victoria and Tasmania. Here, we report data comparing an independent sample of 817 PD patients from Queensland to 1078 consecutive Australian male newborns from Victoria. We confirmed the earlier finding by observing a significant excess of GZ alleles in PD (4.8%) compared to controls (1.5%). Although both studies provided evidence in support of an association between GZ-carrier status and increased risk for parkinsonism, the existing evidence in the literature from screening studies remains equivocal and we discuss the need for alternative approaches to resolve the issue.

Meeting the challenge of interpreting high-resolution single nucleotide polymorphism array data in prenatal diagnosis: does increased diagnostic power outweigh the dilemma of rare variants?

OBJECTIVE: Several studies have already shown the superiority of chromosomal microarray analysis (CMA) compared with conventional karyotyping for prenatal investigation of fetal ultrasound abnormality. This study used very high-resolution single nucleotide polymorphism (SNP) arrays to determine the impact on detection rates of all clinical categories of copy number variations (CNVs), and address the issue of interpreting and communicating findings of uncertain or unknown clinical significance, which are to be expected at higher frequency when using very high-resolution CMA. DESIGN: Prospective validation study. SETTING: Tertiary clinical genetics centre. POPULATION: Women referred for further investigation of fetal ultrasound anomaly. METHODS: We prospectively tested 104 prenatal samples using both conventional karyotyping and high-resolution arrays. MAIN OUTCOME MEASURES: The detection rates for each clinical category of CNV. RESULTS: Unequivocal pathogenic CNVs were found in six cases, including one with uniparental disomy (paternal UPD 14). A further four cases had a 'likely pathogenic' finding. Overall, CMA improved the detection of 'pathogenic' and 'likely pathogenic' abnormalities from 2.9% (3/104) to 9.6% (10/104). CNVs of 'unknown' clinical significance that presented interpretational difficulties beyond results from parental investigations were detected in 6.7% (7/104) of samples. CONCLUSIONS: Increased detection sensitivity appears to be the main benefit of high-resolution CMA. Despite this, in this cohort there was no significant benefit in terms of improving detection of small pathogenic CNVs. A potential disadvantage is the high detection rate of CNVs of 'unknown' clinical significance. These findings emphasise the importance of establishing an evidence-based policy for the interpretation and reporting of CNVs, and the need to provide appropriate pre- and post-test counselling.

Pathogenic aberrations revealed exclusively by single nucleotide polymorphism (SNP) genotyping data in 5000 samples tested by molecular karyotyping.

BACKGROUND: Several recent studies have demonstrated the use of single nucleotide polymorphism (SNP) arrays for the investigation of intellectual disability, developmental delay, autism or congenital abnormalities. In addition to LogR 'copy number' data, these arrays provide SNP genotyping data for gene level autozygosity mapping, estimating low levels of mosaicism, assessing long continuous stretches of homozygosity (LCSH), detection of uniparental disomy, and 'autozygous' regions. However, there remains little specific information on the clinical utility of this genotyping data. METHODS: Molecular karyotyping, using SNP array, was performed on 5000 clinical samples. RESULTS: Clinically significant 'LogR neutral' genotyping abnormalities were detected in 0.5% of cases. Among these were a single case of chimerism, 12 cases with low level chromosome mosaicism, and 11 cases with an LCSH associated with uniparental disomy. In addition, the genotyping data revealed several LCSH associated with clinically relevant 'recessive type' genetic defects. CONCLUSIONS: These results demonstrate the utility of SNP genotyping data for detection of clinically significant abnormalities, including chimerism/mosaicism and recessive Mendelian disorders associated with autozygosity. The incidence of clinically significant low level mosaicism inferred from these cases suggests that this has hitherto been underestimated and chromosome mosaicism frequently occurs in the absence of indicative clinical features. The growing appreciation among clinicians and demand for SNP genotyping data poses significant challenges for the interpretation of LCSH, especially where there is no detailed phenotypic description to direct laboratory analysis. Finally, reporting of unexpected or hidden consanguinity revealed by SNP array analysis raises potential ethical and legal issues.

White matter changes in basis pontis in small expansion FMR1 allele carriers with parkinsonism.

Examples of white matter hyperintensities (wmh) on magnetic resonance images in a basis pontis are presented in two male carriers, each of whom carry a small CGG expansion fragile X mental retardation (FMR1) allele. One carried a premutation (PM) allele of 85 CGG repeats and the other, a gray zone (GZ) allele of 47 repeats. Both were originally diagnosed with idiopathic Parkinson's disease (iPD). Similar changes are also shown in one PM carrier of 99 repeats affected with mild tremor and imbalance, who was ascertained through a fragile X syndrome family. These examples draw attention to the occurrence of wmh in a basis pontis in the carriers of small CGG expansions presenting with tremor and ataxia. Moreover, the presence of this change in GZ, as well as PM, allele carriers originally diagnosed with iPD supports our earlier suggestion that both these alleles may contribute to the neurodegenerative changes in this disorder which, in the examples presented, have been reflected by wmh, most prominent in the cerebellar peduncles and/or pontine area.

Detection of cryptic pathogenic copy number variations and constitutional loss of heterozygosity using high resolution SNP microarray analysis in 117 patients referred for cytogenetic analysis and impact on clinical practice.

BACKGROUND: Microarray genome analysis is realising its promise for improving detection of genetic abnormalities in individuals with mental retardation and congenital abnormality. Copy number variations (CNVs) are now readily detectable using a variety of platforms and a major challenge is the distinction of pathogenic from ubiquitous, benign polymorphic CNVs. The aim of this study was to investigate replacement of time consuming, locus specific testing for specific microdeletion and microduplication syndromes with microarray analysis, which theoretically should detect all known syndromes with CNV aetiologies as well as new ones. METHODS: Genome wide copy number analysis was performed on 117 patients using Affymetrix 250K microarrays. RESULTS: 434 CNVs (195 losses and 239 gains) were found, including 18 pathogenic CNVs and 9 identified as "potentially pathogenic". Almost all pathogenic CNVs were larger than 500 kb, significantly larger than the median size of all CNVs detected. Segmental regions of loss of heterozygosity larger than 5 Mb were found in 5 patients. CONCLUSIONS: Genome microarray analysis has improved diagnostic success in this group of patients. Several examples of recently discovered "new syndromes" were found suggesting they are more common than previously suspected and collectively are likely to be a major cause of mental retardation. The findings have several implications for clinical practice. The study revealed the potential to make genetic diagnoses that were not evident in the clinical presentation, with implications for pretest counselling and the consent process. The importance of contributing novel CNVs to high quality databases for genotype-phenotype analysis and review of guidelines for selection of individuals for microarray analysis is emphasised.

Small CGG repeat expansion alleles of FMR1 gene are associated with parkinsonism.

Fragile X-associated tremor/ataxia syndrome (FXTAS) affects older males carrying premutation, that is, expansions of the CGG repeat (in the 55-200 range), in the FMR1 gene. The neurological changes are linked to the excessive FMR1 messenger RNA (mRNA), becoming toxic through a 'gain-of-function'. Because elevated levels of this mRNA are also found in carriers of the smaller expansion (grey zone) alleles, ranging from 40 to 54 CGGs, we tested for a possible role of these alleles in the origin of movement disorders associated with tremor. We screened 228 Australian males affected with idiopathic Parkinson's disease and other causes of parkinsonism recruited from Victoria and Tasmania for premutation and grey zone alleles. The frequencies of either of these alleles were compared with the frequencies in a population-based sample of 578 Guthrie spots from consecutive Tasmanian male newborns (controls). There was a significant excess of premutation carriers (Fisher's exact test p = 0.006). There was also a more than twofold increase in grey zone carriers in the combined sample of the Victorian and Tasmanian cases, with odds ratio (OR ) = 2.36, and 95% confidence intervals (CI): 1.20-4.63, as well as in Tasmanian cases only (OR = 2.33, 95% CI: 1.06-5.13), compared with controls. The results suggest that the FMR1 grey zone alleles, as well as premutation alleles, might contribute to the aetiology of disorders associated with parkinsonism.

A low symptomatic form of neurodegeneration in younger carriers of the FMR1 premutation, manifesting typical radiological changes.

Fragile X-associated tremor/ataxia (FXTAS) is a late onset disorder caused by a premutation in the FMR1 gene, in which neurological symptoms are associated with white matter (wm) changes, especially within the middle cerebellar peduncles (MCP sign), seen on magnetic resonance images (MRIs). We report a discrepancy between obvious radiological presentations and minimal clinical involvement in two younger male premutation carriers. These carriers, aged 52 and 39 years, showed distinct MCP sign, but reported no neurological symptoms. If this discrepancy represents the initial stage of FXTAS, our findings suggest the possibility of early diagnosis from MRI scans.

Acute peroneal tendon tears.

Acute peroneal tendon tears lay at one end of a spectrum of peroneal tendon pathology. Because a tear represents a mechanical abnormality, surgical treatment is frequently required. Anatomical variants need to be considered as potential causes of lateral ankle pain. Most acute peroneus brevis tears are longitudinal, occur adjacent to the tip of the fibula, and require surgical treatment. Acute peroneus longus tears more commonly occur at the level of the cuboid tunnel and may initially be managed nonoperatively, but, if associated with stenosing tendonitis, may require debridement and tenodesis. Rarely, complete ruptures of both peronei occur and, if there is a significant defect, reconstructive procedures are required.

Reliability of the English version of the painDETECT questionnaire.

BACKGROUND: The painDETECT questionnaire (PD-Q) has been used widely for the identification of neuropathic pain (NeP); however, the reliability of the English version of the PD-Q has never been investigated. OBJECTIVE: This study aimed to determine the reliability of the PD-Q pre- (T0) and immediately post- (T1) clinical consultation and at one-week follow-up (T2). METHODS: We recruited 157 patients attending a Neurosurgery Spinal Clinic and Pain Management Department. Minor changes to PD-Q instructions were made to facilitate patient understanding; however, no changes to individual items or scoring were made. Intraclass correlation coefficients (ICCs) were used to assess the reliability of PD-Q total scores between T0-T1 and T0-T2; weighted kappa (κ) was used to assess the agreement of PD-Q classifications (unlikely NeP, ambiguous, likely NeP) between all time-points. To ensure stability of clinical pain, patients scoring ≤2 or ≥6 on the Patient Global Impression Scale (PGIC) at T2 were excluded from the T0-T2 analysis. RESULTS: Accounting for missing data and exclusions (change in PGIC score), data for 136 individuals (mean [SD] age: 56.8 [15.2]; 54% male) was available, of whom n = 129 were included in the T0-T1 and n = 69 in the T0-T2 comparisons. There was almost perfect agreement between the PD-Q total scores at T0-T1 time-points (ICC 0.911; 95% CI: 0.882-0.941) and substantial agreement at T0-T2 (ICC 0.792; 95% CI: 0.703-0.880). PD-Q classifications demonstrated substantial agreement for T0-T1 (weighted κ: 0.771; 95% CI: 0.683-0.858) and for T0-T2 (weighted κ: 0.691; 95% CI: 0.553-0.830). Missing data was accounted in 13% of our cohort and over 42% of our patients drew multiple pain areas on the PD-Q body chart. CONCLUSION: The English version of the PD-Q is reliable as a screening tool for NeP. The validity of the questionnaire is still in question and has to be investigated in future studies.

Quorum-sensing in Gram-negative bacteria.

It has become increasingly and widely recognised that bacteria do not exist as solitary cells, but are colonial organisms that exploit elaborate systems of intercellular communication to facilitate their adaptation to changing environmental conditions. The languages by which bacteria communicate take the form of chemical signals, excreted from the cells, which can elicit profound physiological changes. Many types of signalling molecules, which regulate diverse phenotypes across distant genera, have been described. The most common signalling molecules found in Gram-negative bacteria are N-acyl derivatives of homoserine lactone (acyl HSLs). Modulation of the physiological processes controlled by acyl HSLs (and, indeed, many of the non-acyl HSL-mediated systems) occurs in a cell density- and growth phase-dependent manner. Therefore, the term 'quorum-sensing' has been coined to describe this ability of bacteria to monitor cell density before expressing a phenotype. In this paper, we review the current state of research concerning acyl HSL-mediated quorum-sensing. We also describe two non-acyl HSL-based systems utilised by the phytopathogens Ralstonia solanacearum and Xanthomonas campestris.

ß-glucuronidase mRNA levels are correlated with gait and working memory in premutation females: understanding the role of FMR1 premutation alleles.

Fragile X tremor ataxia syndrome (FXTAS) is a late-onset disorder manifesting in a proportion of FMR1 premutation individuals (PM: 55-199 CGG triplet expansions). FXTAS is associated with elevated levels of FMR1 mRNA which are toxic. In this study, relationships between neurocognitive and intra-step gait variability measures with mRNA levels, measured in blood samples, were examined in 35 PM and 35 matched control females. The real-time PCR assays measured FMR1 mRNA, and previously used internal control genes: ß-Glucuronidase (GUS), Succinate Dehydrogenase 1 (SDHA) and Eukaryotic Translation Initiation Factor 4A (EI4A2). Although there was significant correlation of gait variability with FMR1 mRNA levels (p = 0.004) when normalized to GUS (FMR1/GUS), this was lost when FMR1 was normalized to SDHA and EI4A2 (2IC). In contrast, GUS mRNA level normalized to 2IC showed a strong correlation with gait variability measures (p < 0.007), working memory (p = 0.001) and verbal intelligence scores (p = 0.008). PM specific changes in GUS mRNA were not mediated by FMR1 mRNA. These results raise interest in the role of GUS in PM related disorders and emphasise the importance of using appropriate internal control genes, which have no significant association with PM phenotype, to normalize FMR1 mRNA levels.

Brain structure and intragenic DNA methylation are correlated, and predict executive dysfunction in fragile X premutation females.

DNA methylation of the Fragile X mental retardation 1 (FMR1) exon 1/intron 1 boundary has been associated with executive dysfunction in female carriers of a FMR1 premutation (PM: 55-199 CGG repeats), whereas neuroanatomical changes have been associated with executive dysfunction in PM males. To our knowledge, this study for the first time examined the inter-relationships between executive function, neuroanatomical structure and molecular measures (DNA methylation and FMR1 mRNA levels in blood) in PM and control (<44 CGG repeats) females. In the PM group, FMR1 intron 1 methylation was positively associated with executive function and cortical thickness in middle and superior frontal gyri, and left inferior parietal gyrus. By contrast, in the control group, FMR1 intron 1 methylation was negatively associated with cortical thickness of the left middle frontal gyrus and superior frontal gyri. No significant associations were revealed for either group between FMR1 mRNA and neuroanatomical structure or executive function. In the PM group, the lack of any significant association between FMR1 mRNA levels and phenotypic measures found in this study suggests that either FMR1 expression is not well conserved between tissues, or that FMR1 intron 1 methylation is linked to neuroanatomical and cognitive phenotype in PM females via a different mechanism.

The reticuloendothelial system and low density lipoprotein metabolism in the rabbit.

This study examines the role of the reticuloendothelial system in the metabolism and tissue uptake of chemically modified human low density lipoprotein (LDL) in rabbits. Treatment with 1,2-cyclohexanedione or HCHO/NaBH4 abolishes receptor-mediated catabolism of the lipoprotein and restricts its clearance to receptor-independent pathways. When the plasma clearances of the two modified lipoproteins were measured in rabbits the 1,2-cyclohexanedione-treated LDL was removed 19% faster (P less than 0.001) than HCHO/NaBH4-treated LDL. This was associated with an increased uptake of 1,2-cyclohexanedione-treated LDL over HCHO/NaBH4-treated LDL into tissues, particularly the liver and spleen, suggesting that their differential clearance may have involved the reticuloendothelial system. To examine this possibility the experiment was repeated in animals whose reticuloendothelial activity had been suppressed by injections of an ethyl oleate emulsion. This reduced the difference in the plasma clearance rates of 1,2-cyclohexanedione-treated LDL and HCHO/NaBH4-treated LDL and virtually abolished their differential tissue uptakes, adding weight to the proposal that the reticuloendothelial system may be involved in the receptor-independent catabolism of LDL.

Receptor-mediated catabolism and tissue uptake of human low density lipoprotein in the cholesterol-fed, atherosclerotic rabbit.

The LDL receptor pathway, which was delineated in cultured cells, is now known to operate in vivo. In this study we have measured the plasma clearances and tissue uptakes of native and chemically modified (1,2-cyclohexanedione-treated or reductively methylated) LDL in rabbits in order to determine the response of the pathway to a high-cholesterol diet. 1 week on the diet increased circulating LDL and suppressed its receptor-mediated plasma clearance and uptake into all tissues. The fractional catabolic rate of the lipoprotein via the receptor-independent route also fell. Continuation of the feeding program for 12 weeks accentuated these changes and virtually eliminated receptor uptake into all tissues so that the plasma decay curves of native and cyclohexanedione-treated LDL were superimposable. Lipoprotein assimilation by the aorta, however, did not follow this general trend. This tissue, after 12 weeks, was variably infiltrated by atheromatous deposits and the appearance of these lesions was associated with a substantial increase in the relative uptakes of both native and chemically modified (cyclohexanedione-treated and reductively methylated) LDL. We concluded (a) that expansion of tissue cholesterol pools virtually abolishes LDL receptor activity in rabbits; and (b) that LDL assimilation (both apparently receptor-mediated and receptor-independent) paradoxically increases at sites where the aorta is affected by atheromatous lesions.

Receptor-independent low-density lipoprotein catabolism. Evaluation of 2-hydroxyacetaldehyde-treated lipoprotein as a probe for its measurement.

This study examines the protein modification procedures available for inhibiting receptor recognition of low-density lipoprotein (LDL). Glycosylation with glucose, idose or ribose blocks the interaction of the lipoprotein with the high-affinity LDL receptor on cultured fibroblast membranes and delays its clearance from the plasma of rabbits. However, the prolonged incubation required in the process also changes the metabolic properties of the lipoprotein. An alternative approach using 2-hydroxyacetaldehyde-treated LDL completely blocks receptor recognition. This modified tracer has the same metabolic properties as the reductively methylated lipoprotein in rabbits and appears to be a suitable probe for the measurement of the receptor-independent LDL catabolic pathway in humans.

Preinjury behavioral and emotional problems among pediatric burn patients.

Standardized behavior rating scales have been used in the routine care of children during medical visits because they provide an objective, norm-based index for the child's behavioral functioning. The purpose of this study was to examine behavior problems among children (aged 2.5-18 years) with burn injuries using the Behavioral Assessment System for Children, a multi-informant system of standardized rating scales that assesses clinical and adaptive behavior areas. Parents and youth (ages 8-18) completed the Behavioral Assessment System for Children with reference to the pediatric patient's behavioral functioning before hospital admission for a burn injury. In total, data were collected on 94 children. Results suggested that a substantial portion of the sample endorsed significantly elevated levels of behavioral difficulties across a broad range of problem behaviors. On the basis of parent report, preschoolers exhibited concerns related to hyperactivity, anxiety, aggression, and attention problems, whereas school-aged children were reported to have these same concerns as well as depression and conduct problems. Twenty percent of our adolescent sample (ages 12-18 years) were described to be experiencing even more internalizing and externalizing behavior problems relative to the two groups of their younger counterparts. Boys were found to contribute to the cause of their burn injury significantly more often than girls. The strengths, limitations, and clinical implications of our findings are discussed.

Expression of the gum operon directing xanthan biosynthesis in Xanthomonas campestris and its regulation in planta.

The gum gene cluster of Xanthomonas campestris pv. campestris comprises 12 genes whose products are involved in the biosynthesis of the extracellular polysaccharide xanthan. These genes are expressed primarily as an operon from a promoter upstream of the first gene, gumB. Although the regulation of xanthan synthesis in vitro has been well studied, nothing is known of its regulation in planta. A reporter plasmid was constructed in which the promoter region of the gum operon was fused to gusA. In liquid cultures, the expression of the gumgusA reporter was correlated closely with the production of xanthan, although a low basal level of beta-glucuronidase activity was seen in the absence of added carbon sources when xanthan production was very low. The expression of the gumgusA fusion also was subject to positive regulation by rpfF, which is responsible for the synthesis of the diffusible signal factor (DSF). The expression of the gumgusA fusion in bacteria recovered from inoculated turnip leaves was maximal at the later phases of growth and was subject to regulation by rpfF. These results provide indirect support for the operation of the DSF regulatory system in bacteria in planta.