POS0161-HPR BARRIERS AND FACILITATORS RELATED TO SELF-MANAGEMENT OF SHOULDER PAIN: A SYSTEMATIC REVIEW AND QUALITATIVE SYNTHESIS

Background:

Shoulder pain is a significant cause of pain and disability in the general population.1 Current research suggests that shoulder pain can be resistant to treatment and is often recurrent.2 Systematic review-level evidence shows modest short-term benefits for most current treatments.3 Effective self-management strategies that equip patients with the necessary tools to self-manage their condition are urgently required. However, engagement with self-management is poor, potentially compromising treatment outcomes and contributing to ongoing disability.4

Objectives:

The objectives of this review were to:

•Systematically identify and appraise relevant qualitative evidence on barriers and facilitators relating to self-management from the perspectives of people with shoulder pain and healthcare professionals.

•Collate and synthesise this evidence, to gain an understanding of factors that influence self-management of shoulder pain.

•Develop evidence-based recommendations to inform the implementation and delivery of self-management programmes for shoulder pain.

Methods:

A meta-aggregative approach to the synthesis of qualitative evidence was used. Twelve databases were searched, from inception to 13 July 2020, to identify studies exploring barriers and facilitators related to self-management of shoulder pain from the perspectives of people with shoulder pain and clinicians involved in the care of such patients. Two independent reviewers identified eligible articles, extracted the data and conducted critical appraisal. Two reviewers independently identified and developed categories, with validation by two further researchers. Categories were discussed among the wider research team and a comprehensive set of synthesized findings was derived.

Results:

Sixteen studies were included in the review, exploring several shoulder conditions: shoulder instability; rotator cuff-related pain; dysfunction post rotator cuff surgery; and degenerative rotator cuff tears. From the perspective of patients, three synthesized findings were identified that influenced self-management: (1) support for self-management, including subthemes related to patient-centred support, knowledge, time, access to equipment, and patient digital literacy; (2) personal factors, including patient beliefs, patient expectations, patient motivation, pain, and therapeutic response; and (3) external factors, including influence of the clinician and therapeutic approach. From the perspective of clinicians, two synthesized findings were identified that influenced adherence to self-management: (1) support for self-management, including education, patient-centred support, patient empowerment, time, and clinician digital literacy; and (2) preferred management approach, including clinician beliefs, expectations, motivation, therapeutic approach, and therapeutic response.

Conclusion:

Patients and clinicians identified several barriers and facilitators that influenced self-management of shoulder pain. Clinicians’ awareness of these factors could positively influence patient management, enhance patients’ ability to self-manage, and improve treatment outcomes.

References:

[1]Walker-Bone K, Palmer KT, Reading I, Coggon D, Cooper C. Prevalence and impact of musculoskeletal disorders of the upper limb in the general population. Arthritis and Rheumatism. 2004;51(4): 642-651.

[2]Croft P, Pope D, Silman A. The clinical course of shoulder pain: prospective cohort study in primary care. Primary Care Rheumatology Society Shoulder Study Group. British Medical Journal. 1996;313(7057): 601-602.

[3]Littlewood C, May S, Walters S. A review of systematic reviews of the effectiveness of conservative interventions for rotator cuff tendinopathy. Shoulder & Elbow. 2013;5(3): 151-167.

[4]Littlewood C, Malliaras P, Mawson S, May S, Walters S. Patients with rotator cuff tendinopathy can successfully self-manage, but with certain caveats: a qualitative study. Physiotherapy. 2014;100(1): 80-85.

Disclosure of Interests:

Aidan O’Shea: None declared, Jonathan Drennan: None declared, Chris Littlewood: None declared, Helen Slater Speakers bureau: AbbVie PTY LTD 2018, Julius Sim: None declared, Joseph McVeigh: None declared

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

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.

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.

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.

Offering fragile X syndrome carrier screening: a prospective mixed-methods observational study comparing carrier screening of pregnant and non-pregnant women in the general population

INTRODUCTION

Fragile X syndrome (FXS) is the leading cause of inherited intellectual and developmental disability. Policy development relating to carrier screening programmes for FXS requires input from large studies examining not only test uptake but also psychosocial aspects. This study will compare carrier screening in pregnant and non-pregnant populations, examining informed decision-making, psychosocial issues and health economics.

METHODS AND ANALYSIS

Pregnant and non-pregnant women are being recruited from general practices and obstetric services. Women receive study information either in person or through clinic mail outs. Women are provided pretest counselling by a genetic counsellor and make a decision about testing in their own time. Data are being collected from two questionnaires: one completed at the time of making the decision about testing and the second 1 month later. Additional data are gathered through qualitative interviews conducted at several time points with a subset of participating women, including all women with a positive test result, and with staff from recruiting clinics. A minimum sample size of 500 women/group has been calculated to give us 88% power to detect a 10% difference in test uptake and 87% power to detect a 10% difference in informed choice between the pregnant and non-pregnant groups. Questionnaire data will be analysed using descriptive statistics and multivariate logistic regression models. Interview data will be thematically analysed. Willingness-to-pay and cost effectiveness analyses will also be performed. Recruitment started in July 2009 and data collection will be completed by December 2013.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Universities of Melbourne and Western Australia and by recruiting clinics, where required. Results will be reported in peer-reviewed publications, conference presentations and through a website http://www.fragilexscreening.net.au. The results of this study will make a significant contribution to discussions about the wider introduction of population carrier screening for FXS.

The effect of massage on heart rate variability in preterm infants

OBJECTIVE

To test the hypothesis that massage would improve autonomic nervous system (ANS) function as measured by heart rate variability (HRV) in preterm infants.

STUDY DESIGN

Medically stable, 29- to 32-week preterm infants (17 massage, 20 control) were enrolled in a masked, randomized longitudinal study. Licensed massage therapists provided the massage or control condition twice a day for 4 weeks. Weekly HRV, a measure of ANS development and function, was analyzed using SPSS generalized estimating equations.

RESULTS

Infant characteristics were similar between groups. HRV improved in massaged infants but not in the control infants (P<0.05). Massaged males had a greater improvement in HRV than females (P<0.05). HRV in massaged infants was on a trajectory comparable to term-born infants by study completion.

CONCLUSION

Massage-improved HRV in a homogeneous sample of hospitalized, medically stable, preterm male infants and may improve infant response to exogenous stressors. We speculate that massage improves ANS function in these infants.

Low back pain-related beliefs and likely practice behaviours among final-year cross-discipline health students

BACKGROUND

Evidence points to clinicians' beliefs and practice behaviours related to low back pain (LBP), which are discordant with contemporary evidence. While interventions to align beliefs and behaviours with evidence among clinicians have demonstrated effectiveness, a more sustainable and cost-effective approach to positively developing workforce capacity in this area may be to target the emerging workforce. The aim of this study was to investigate beliefs and clinical recommendations for LBP, and their alignment to evidence, in Australian university allied health and medical students.

METHODS

Final-year students in chiropractic, medicine, occupational therapy, pharmacy and physiotherapy disciplines in three Western Australian universities responded to a survey. Demographic data, LBP-related beliefs data [modified Health Care Providers Pain and Impact Relationship Scale (HC-PAIRS) and the Back Pain Beliefs Questionnaire (BBQ)] and activity, rest and work clinical recommendations for an acute LBP clinical vignette were collected.

RESULTS

Six hundred two students completed the survey (response rate 74.6%). Cross-discipline differences in beliefs and clinical recommendations were observed (p > 0.001). Physiotherapy and chiropractic students reported significantly more helpful beliefs compared with the other disciplines, while pharmacy students reported the least helpful beliefs. A greater proportion of chiropractic and physiotherapy students reported guideline-consistent recommendations compared with other disciplines. HC-PAIRS and BBQ scores were strongly associated with clinical recommendations, independent to the discipline of study and prior experience of LBP.

CONCLUSIONS

Aligning cross-discipline university curricula with current evidence may provide an opportunity to facilitate translation of this evidence into practice with a focus on a consistent, cross-discipline approach to LBP management.

Tactile/kinesthetic stimulation (TKS) increases tibial speed of sound and urinary osteocalcin (U-MidOC and unOC) in premature infants (29-32weeks PMA)

Preterm delivery (<37 weeks post-menstrual age) is associated with suboptimal bone mass. We hypothesized that tactile/kinesthetic stimulation (TKS), a form of infant massage that incorporates kinesthetic movement, would increase bone strength and markers of bone accretion in preterm infants. Preterm, AGA infants (29-32 weeks) were randomly assigned to TKS (N=20) or Control (N=20). Twice daily TKS was provided 6 days per week for 2 weeks. Control infants received the same care without TKS treatment. Treatment was masked to parents, health care providers, and study personnel. Baseline and week two measures were collected for tibial speed of sound (tSOS, m/sec), a surrogate for bone strength, by quantitative ultrasound (Sunlight8000) and urine markers of bone metabolism, pyridinium crosslinks and osteocalcin (U-MidOC and unOC). Infant characteristics at birth and study entry as well as energy/nutrient intake were similar between TKS and Control. TKS intervention attenuated the decrease in tSOS observed in Control infants (p<0.05). Urinary pyridinium crosslinks decreased over time in both TKS and CTL (p<0.005). TKS infants experienced greater increases in urinary osteocalcin (U-MidOC, p<0.001 and unOC, p<0.05). We conclude that TKS improves bone strength in premature infants by attenuating the decrease that normally follows preterm birth. Further, biomarkers of bone metabolism suggest a modification in bone turnover in TKS infants in favor of bone accretion. Taken together, we speculate that TKS improves bone mineralization.

The use of esmarch exsanguination for the treatment of extremity wound burns

Tourniquets are routinely used during the excising and grafting of burn wounds located on the limbs in order to decrease blood loss. It has been postulated that the exsanguination of extremities by using Esmarch bandages might further reduce blood loss. However, there are concerns about a decrease in graft quality when Esmarch bandages are applied. The purpose of this prospective, double-blinded randomized study was to compare Esmarch application in addition to tourniquet (exsanguinated extremities) with the application of tourniquet alone. Thirty-eight excisions of bilateral extremity wounds were performed. Both limbs were tangentially excised after tourniquet application with one limb randomly chosen for prior Esmarch exsanguination. Blood loss was estimated during this procedure. Graft take was assessed twice: on post-operative days 3 and 7. The burn surface area and total area grafted were equivalent in the extremities with Esmarch bandages when compared to the extremities without them. Total blood loss was less in the extremities where Esmarch was applied. Graft take was similar in the two groups. Statistical analysis was performed with a two-tailed paired T-test. It is concluded that the use of Esmarch exsanguination in addition to tourniquet further reduces blood loss without affecting the quality of the engraftment.

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.

Analysis of deep vein thrombosis in burn patients

OBJECTIVE

Deep vein thrombosis (DVT) represents a major cause of morbidity in surgical patients. Controversial reports exist on the incidence of DVT in burn patients. We report our experience over a 10-year period.

METHODS

Patients admitted to our Burn Unit over the period 1991-2001 and diagnosed with DVT were identified. Their records were retrospectively reviewed for demographic factors, extent and severity of burn injury and outcome.

RESULTS

A total of 4102 patients were admitted to the WPH Burn unit during the study period. All patients received routine subcutaneous heparin prophylaxis. Ten patients were diagnosed with DVT (0.25%). Compared to our total burn population, these patients were older (mean age 47 +/- 22.7 years versus 35 +/- 22 years P = 0.14) and had more extensive burns (mean total body surface area (TBSA) 34.7 +/- 25.3% versus 12 +/- 15.7% P = 0.02). Two patients developed non-fatal pulmonary embolism (PE). There were three deaths, none due to thromboembolic disease. There were no complications from the routine administration of subcutaneous heparin.

CONCLUSION

The incidence of DVT in our study is much less than the incidence reported in other critically ill patients and less than that of most reports on burn patients. In our experience, routine heparin prophylaxis is effective for the prevention of DVT in burn patients.

Effect of diagnosis and treatment of sinusitis in critically ill burn victims

The purpose of this study was to assess the incidence of diagnosed sinusitis and the effect of diagnosis and treatment on the outcome in critically ill burn victims. Chart analysis of 84 consecutive burn victims requiring mechanical ventilation for greater than 7 days was performed. Sinusitis was diagnosed in 13/84 patients (15%). There was no difference in age or total body surface area burned, or the incidence of inhalation injury, ARDS, pneumonia and sepsis (P>0.05). Co-morbid disease was similar in both the groups. The number of ventilator-dependent days and hospital length of stay were higher in the sinusitis group (P<0.05). The hospital mortality in those diagnosed and treated for sinusitis was 23% (3/13) as opposed to 48% (34/71) in those not diagnosed with sinusitis (P<0.05). Increased number of ventilator-dependent days and longer hospital stay are associated with the diagnosis of sinusitis. Our findings suggest an improved survival in those diagnosed and treated for sinusitis.

An assessment of burn prevention knowledge in a high burn-risk environment: restaurants

Our facility has seen an increase in the number of cases of children burned in restaurants. Fieldwork has revealed many unsafe serving practices in restaurants in our tristate area. The current research targets what appears to be an underexamined burn-risk environment, restaurants, to examine server knowledge about burn prevention and burn care with customers. Participants included 71 local restaurant servers and 53 servers from various restaurants who were recruited from undergraduate courses. All participants completed a brief demographic form as well as a Burn Knowledge Questionnaire. It was found that server knowledge was low (ie, less than 50% accuracy). Yet, most servers reported that they felt customer burn safety was important enough to change the way that they serve. Additionally, it was found that length of time employed as a server was a significant predictor of servers' burn knowledge (ie, more years serving associated with higher knowledge). Finally, individual items were examined to identify potential targets for developing prevention programs.

Use of a token reinforcement system to promote appropriate behavior at a pediatric burn summer camp

Child behavior management can be an important concern in conducting summer camps for pediatric burn patients, because many of these patients have a history of significant behavioral difficulties. To be efficient, a flexible camp-wide behavior management system, such as a token economy, would be ideal. In this article we discuss the concept and principles of a token reinforcement system and outline how this intervention was applied to our pediatric burn summer camp across 2 consecutive years. We also provide a description of modifications made for the second camp, based on counselor ratings of and our experience with the token system during the first camp. Results from counselor assessments indicated that after using the token system, counselors' perceptions of its utility (eg, effective in decreasing problem behavior in campers, useful in making behavior management easier) increased significantly across both years.

Helicopter transportation of burn patients

Analysis of 437 consecutive acute burn patients transported to our burn center revealed 339 transported by ground and 98 by helicopter. There were 18 air transport patients from within a 25-mile-radius, and 80 flown further than 25 miles. Mean age was the same in all groups (P>0.05). Percent total body surface area (TBSA) burned was 8.26% in ground transport patients, significantly less than the 20.35% (within 25 miles) and 21.40% (greater than 25 miles) seen in helicopter transports (P<0.0001). Three percent of ground transport patients and 28% of helicopter patients had inhalation injury (P<0.0001). There was no difference in incidence of inhalation injury among helicopter groups (28 vs. 29%, P=0.8). In patients with coexistent inhalation injury, the mean TBSA burned was significantly larger when compared with the TBSA of burns without inhalation injury (P<0.001). Air transported groups contained patients whose status was not critical based upon lack of inhalation injury and small burn size, and who could have been transported by ground. Non clinical factors such as insurance status, desire to keep ground ambulances in their community, and competing helicopter services reluctant to refuse to transport a patient appears to be factors in choosing air ambulance transportation. Regional single helicopter services and regional cooperative ground ambulance services should reduce use of helicopter transport of burn patients when it is not clinically indicated.

Karyotype, phenotype and parental origin in 19 cases of triploidy

The parental origin of triploidy in 19 cases was examined by inheritance of DNA microsatellites and by methylation patterns of SNRPN or PW71 (where parents' blood was unavailable). The fetal and placental morphology on these cases was reviewed. The phenotype of the fetuses with non-mosaic triploidy was assessed in relation to the two types described by McFadden and Kalousek. Of the diandric fetuses three of the six showed mild-to-moderate symmetrical growth retardation and the other three had growth characteristics in accordance with their gestational ages. This study would suggest the fetal triploid 'Type 1' definition be modified to 'well grown to moderate symmetrical IUGR' to allow for such variation. In the digynic fetuses (McFadden/Kalousek Type 2) there were poor growth characteristics with IUGR being more severe and asymmetrical. The diandric fetuses were as common as digynic fetuses in this series. The ratio of diandric to digynic specimens was 11:8 but if only fetal specimens (not embryos or mosaic children) were included the ratio was 6:5. Many diandric conceptions end as partial moles but later in gestation diandric fetuses may be well grown. It is proposed that there may be a survival barrier for diandric fetuses early in gestation (possibly based on the proportion of vascularised placental villi), although once this is passed the diandric fetuses are comparatively more viable and better grown than digynic fetuses. In the XXY triploid fetuses, 5/6 had hypoplastic or ambiguous external genitalia (two were recorded as of female phenotype) as has been reported previously. In these, the gonadal histology was testicular in all the diandrics but in the single digynic XXY case, sex reversal was complete with normal uterus and Fallopian tubes and the gonads were histologically ovaries. Two triploid/diploid mosaics were proven to be due to digyny. The probable cause is delayed incorporation of the second polar body into a blastomere and there was evidence of identical alleles from the same sperm being present in both diploid and triploid cells. In one of these triploid/diploid mosaics in which there was a termination of pregnancy (TOP) after prenatal karyotyping the diploid cell line had trisomy 16 which was not evident in the triploid line. This trisomy was probably of post-zygotic origin and we suggest the fetus was rescued by the prominence of the triploid line.

Regulation of the synthesis of cyclic glucan in Xanthomonas campestris by a diffusible signal molecule

The rpf gene cluster of Xanthomonas campestris pv. campestris is involved in the co-ordinate positive regulation of the production of extracellular enzymes and the extracellular polysaccharide xanthan. Several of the rpf genes are involved in a regulatory system involving the small diffusible molecule DSF (for diffusible signal factor). Synthesis of DSF requires RpfF, and a two-component sensory transduction system involving RpfC has been implicated in the perception of the signal and signal transduction. Here we show that mutations in both rpfF and rpfC lead to reductions in the levels of cyclic glucan. The levels of cyclic glucan synthetase in membrane preparations from rpfF and rpfC mutants were, however, unaltered from the wild-type. Similar alterations in the level of cyclic glucan without changes in cyclic glucan synthetase activity were seen when wild-type bacteria were exposed to osmotic stress. These results extend the range of cellular functions subject to regulation by the rpf genes and DSF system.

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.

Mosaic inv dup(8p) marker chromosome with stable neocentromere suggests neocentromerization is a post-zygotic event

Marker chromosomes containing active human neocentromeres have been described in individuals where the chromosomes are non-mosaic, suggesting that they are mitotically stable, but also in individuals where there is mosaicism, raising the possibility of neocentromere instability. We report two independently ascertained individuals who are mosaic for a supernumerary marker chromosome, shown by reverse chromosome painting to have an 8p origin, resulting in mosaicism for tetrasomy 8p23.1-->pter in the patient. The markers have a primary constriction but show no detectable centromeric alpha-satellite DNA. The marker in Patient 1 demonstrated no centromere protein CENP-B binding, but associated with nine different functionally critical centromere proteins. Investigation of peripheral blood lymphocytes from this patient on five separate occasions over a 13-year period showed 23-46% mosaicism for the marker chromosome with no decrease in incidence. In vitro investigation of primary and secondary sub-clones of a lymphoblast cell line derived from the patient demonstrated 100% stability of the marker chromosome indicating that neocentromere instability is unlikely to be responsible for the mosaicism in the patient. This and other available data support a general model of neocentromerization as a post-zygotic event, irrespective of whether the supernumerary chromosome fragment has arisen during meiosis or post-fertilization at mitosis.

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.

A two-component system involving an HD-GYP domain protein links cell-cell signalling to pathogenicity gene expression in Xanthomonas campestris

The synthesis of extracellular enzymes and extracellular polysaccharide (EPS) in Xanthomonas campestris pv. campestris (Xcc) is regulated by a cluster of genes called rpf (for regulation of pathogenicity factors). Two of the genes, rpfF and rpfB, have previously been implicated in the synthesis of a diffusible regulatory molecule, DSF. Here, we describe a screen of transposon insertion mutants of Xcc that identified two DSF-overproducing strains. In each mutant, the gene disrupted is rpfC, which encodes a hybrid two-component regulatory protein in which the sensor and regulator domains are fused and which contains an additional C-terminal phosphorelay (HPt) domain. We show that rpfC is in an operon with rpfH and rpfG. The predicted protein RpfG has a regulatory input domain attached to a specialized version of an HD domain, previously suggested to function in signal transduction. The predicted protein RpfH is structurally related to the sensory input domain of RpfC. We show that RpfC and RpfG act positively to regulate the synthesis of extracellular enzymes and EPS, but that RpfC acts negatively to regulate the synthesis of DSF. We propose that RpfGHC is a signal transduction system that couples the synthesis of pathogenicity factors to sensing of environmental signals that may include DSF itself.

Identification of small FRAXA premutations

BACKGROUND

Diagnosis of fragile X syndrome in mentally retarded individuals is satisfactorily achieved using a Southern blot test that detects the typical triplet repeat expansion (>200 repeats) within the FMR1 gene. All such individuals inherit the mutation from a carrier, who usually shows a lower triplet repeat number and may be asymptomatic. Having identified a fragile X proband, it is necessary to identify related carriers of this familial X-linked dominant mutation to provide family counseling and testing.

METHODS AND RESULTS

For one family in which a fragile XA repeat expansion occurs, Southern blot hybridization did not give accurate sizing data because of the very small premutation associated with the unstable allele. PCR sizing methods and linkage analysis were adapted to identify family members with the premutation.

CONCLUSION

Although most carriers can be detected using Southern blot and/or direct PCR sizing tests, very small expansions (55-70 repeats) are difficult to distinguish from larger, normal alleles. We have used linkage analysis in combination with direct allele analysis to identify carriers of very small expansions of a fragile X chromosome in a four-generation family.

Chromosome analysis of blastomeres from human embryos by using comparative genomic hybridization

Karyotypic studies of aborted fetuses have been used to draw the inference that the proportion of conceptuses with chromosome abnormalities is very high. Fluorescent in situ hybridization (FISH) studies of blastomeres from early cleavage embryos have provided some support for this inference but they are limited to the study of a few chromosomes. We describe the novel application of comparative genomic hybridization (CGH) to the study of numerical and structural abnormalities of single blastomeres from disaggregated 3-day-old human embryos. CGH results were obtained for 63 blastomeres from 12 embryos. Identification of all chromosomes with the exception of chromosomes 17, 19, 20 and 22 was possible. The embryos divided into four groups: (1) embryos with a normal CGH karyotype seen in all blastomeres; (2) embryos with consistent aneuploidy suggesting meiotic non-disjunction had occurred; (3) embryos that were mosaic generally with one or more cells showing aneuploidy for one or two chromosomes but some with cells showing extensive aneuploidy; and (4) one embryo with extensive aneuploidy in all blastomeres. The extensive aneuploidy in group 4 is interpreted as corresponding to the random aneuploidy seen in "chaotic" embryos reported by using interphase FISH. Partial chromosome loss and gain following chromosome breakage was observed in one embryo. Our analysis provides basic biological information on the occurrence of constitutional and post-zygotic chromosome abnormalities in early human embryos. Used in conjunction with embryo biopsy, diagnostic CGH should allow the exclusion of a proportion of embryos that appear normal but that have a poor probability of survival and, therefore, may improve the implantation rate after in vitro fertilization.

Detection of aneuploidy in single cells using comparative genomic hybridization

The ability of comparative genomic hybridization (CGH) to detect aneuploidy following universal amplification of DNA from a single cell, or a small number of cells, was investigated with a view to preimplantation diagnosis following in vitro fertilization, and prenatal diagnosis using fetal erythroblasts obtained from maternal blood. The DNA obtained from lysed single cells was amplified using degenerate oligonucleotide-primed PCR (DOP-PCR). This product was labelled using nick translation and hybridized together with normal reference genomic DNA. The CGH fluorescent ratio profiles obtained could be used to determine aneuploidy with cut-off thresholds of 0.75 and 1.25. Deviation in the profiles in the heterochromatic regions was reduced by using, as a reference sample, normal genomic DNA that had also undergone DOP-PCR. Single cells known to be trisomic for chromosomes 13, 18 or 21 were analysed using this technique. The resolution of CGH with amplified DNA from a single cell is of the order of 40 Mb, sufficient for the diagnosis of trisomy 21, and possibly segmental aneuploidy of equivalent size. These results, and those of others, demonstrate that diagnosis of chromosomal aneuploidy in single cells is possible using CGH with DOP-PCR amplified DNA.

Trisomy 20p resulting from inverted duplication and neocentromere formation

Normal human centromeres contain large tandem arrays of alpha-satellite DNA of varying composition and complexity. However, a new class of mitotically stable marker chromosomes which contain neocentromeres formed from genomic regions previously devoid of centromere activity was described recently. These neocentromeres are fully functional yet lack the repeat sequences traditionally associated with normal centromere function. We report here a supernumerary marker chromosome derived from the short arm of chromosome 20 in a patient with manifestations of dup(20p) syndrome. Detailed cytogenetic, FISH, and polymorphic microsatellite analyses indicate the de novo formation of the marker chromosome during meiosis or early postzygotically, involving an initial chromosome breakage at 20p11.2, followed by an inverted duplication of the distal 20p segment due to rejoining of sister chromatids and the activation of a neocentromere within 20p12. This inv dup(20p) marker chromosome lacks detectable centromeric alpha-satellite and pericentric satellite III sequences, or centromere protein CENP-B. Functional activity of the neocentromere is evidenced by its association with 5 different, functionally critical centromere proteins: CENP-A, CENP-C, CENP-E, CENP-F, and INCENP. Formation of a neocentromere on human chromosome 20 has not been reported previously and in this context represents a new mechanism for the origin of dup(20p) syndrome.

Syndromal obesity due to paternal duplication 6(q24.3-q27)

The likelihood of a paternally expressing imprinted gene in chromosome region 6(q23-24) has been highlighted by cases of transient neonatal diabetes mellitus (TNDM) in which paternal uniparental disomy (UPD) for chromosome 6 or paternal duplication 6(q23-qter) was detected. We present the case of a 38-year-old man with moderate to severe intellectual delay, short stature, small hands and feet, eye abnormality, small mouth, and obesity (without hyperphagia) beginning in mid-childhood. The perinatal and neonatal histories were normal. The patient had a duplication within 6q. Fluorescence in situ hybrisation studies were performed with single and dual hybridisations using a chromosome 6 library probe, short and long arm subregional probes, 6q23-24, 6q25.3-6qter locus-specific probes, and a 6q telomere probe. The hybridisation results defined an inverted duplication of 6q24.3 to 6q27. DNA studies with microsatellite markers from 6p and 6q showed regular biparental inheritance of chromosome 6 and confirmed that the duplication was paternal in origin. Our patient appears to be the first one known to have paternal duplication of chromosome area 6(q24-q27) who did not have TNDM as an infant. He has remained nondiabetic, although obesity, without hyperphagia, has been a constant problem since its onset in mid-childhood.

The fragile X syndrome

Fragile X syndrome (FXS) is the most common cause known of inherited developmental disability. New and widely available techniques in DNA analysis allow both affected individuals and carriers to be tested from a simple blood sample. It is now recognised that a wide range of clinical severity occurs in both sexes. Specific treatment and interventional strategies are now available and of great benefit to individuals, families and carers. Genetic counselling allows families to make informed decisions. General practitioners can play a central role in detection and management of this syndrome.

Screening for diabetic retinopathy in primary care: retinal photography alone can be used efficiently and effectively to exclude those with sight threatening lesions

BACKGROUND

Good screening performance of retinal photography and ophthalmoscopy together in screening for diabetic retinopathy in primary care have been reported. This study reanalysed the data to evaluate the screening performance of photography alone.

METHODS

One thousand and ten patients screened by fundal photography and ophthalmoscopy were studied retrospectively. Fundal photographs were quality graded with poor quality pictures being excluded from the analysis. Each patient was reviewed initially by both retinal photographs and ophthalmoscopy by an ophthalmologist, the "gold standard". Six months later the fundal photographs were reviewed and reported in a blinded manner by the ophthalmologist.

RESULTS

Two thousand and fourteen photographs were obtained, of which 162 (8%) had to be excluded because of poor quality. On review of the remaining 1852 photographs in isolation, of 77 cases of severe retinopathy as determined by the "gold standard", 67 had severe changes on photography--detection rate 87%. Of the 1775 cases without sight threatening retinopathy only five were judged to have sight threatening changes on photography--false positive rate 0.3%. Considering sight threatening and background retinopathy together, the detection rate was 69% (257 of 375) and the false positive rate 1.6% (23 of 1477).

CONCLUSION

Good quality fundal photographs alone seem specific enough to screen for sight threatening diabetic retinopathy, but will underdetect background retinopathy.

Transforming growth factor beta 1 and interleukin 4 induced alpha smooth muscle actin expression and myofibroblast-like differentiation in human synovial fibroblasts in vitro: modulation by basic fibroblast growth factor

OBJECTIVE

To discover if alpha smooth muscle actin expression and myofibroblastic differentiation are induced in synovial fibroblasts by cytokines found in the inflamed RA joint.

METHODS

Immunofluorescent microscopy and western blotting were used to examine different cultures of human synovial fibroblasts for expression of alpha actin in the presence of the cytokines transforming growth factor beta (TGF beta 1), interleukin 1 alpha (IL1 alpha), IL4, IL6, tumour necrosis factor alpha (TNF alpha), and basic fibroblast growth factor (FGF).

RESULTS

A small but significant population of cells (14.4 +/- 12.9%) expressed alpha actin under standard culture conditions. Upon treatment with TGF beta 1 there was a pronounced increase in the number of cells expressing alpha actin (68.1 +/- 5.49%), accompanied by a change in morphology to a myofibroblast-like phenotype. Other cytokines found within the inflamed joint such as IL1, TNF alpha, IL6, and basic FGF failed to induce alpha actin expression. However, IL4, which is normally absent or only present at low concentrations in the RA joint had a similar effect to TGF beta 1. It was also found that basic FGF inhibited the induction of alpha actin expression by TGF beta 1 and IL4.

CONCLUSION

In the presence of TGF beta 1 or IL4, fibroblasts derived from synovial tissue or synovial fluid are induced to differentiate into myofibroblast-like cells containing the alpha smooth muscle form of actin. This differentiation is inhibited by basic FGF. It is suggested that the balance between these particular cytokines may be important in the modulation of fibroblast behaviour, which could have significant effects on joint repair mechanisms and the generation of fibrous tissue within the rheumatoid joint.

A novel regulatory system required for pathogenicity of Xanthomonas campestris is mediated by a small diffusible signal molecule

Mutations in the seven clustered rpf genes cause downregulated synthesis of extracellular enzymes and reduced virulence of Xanthomonas campestris pathovar campestris (Xcc). The phenotype of mutants in one of the genes, rpfF, can be restored by a diffusible extracellular factor (DSF) produced by all Xcc strains tested, apart from rpfF and rpfB mutants. DSF accumulates in early stationary phase (when synthesis of enzymes is maximal), but levels decline subsequently. Addition of DSF to exponentially-growing wild-type bacteria does not cause precocious enzyme synthesis. rpfB and rpfF are expressed throughout growth, but the rate increases in early stationary phase. RpfB is predicted to be a long-chain fatty acyl CoA ligase, and RpfF shows some relatedness to enoyl CoA hydratases. The properties of DSF suggest that it may be a fatty-acid derivative, and certain lipid preparations possess DSF activity at higher concentrations. These include lipid extracts and acid-hydrolysed lipoplysaccharide and lipid A from Xcc, and purified dodecanoic and hydroxydodecanoic acid. DSF production is confined to certain xanthomonads. We propose a model for the DSF system, which represents a novel mechanism for regulating virulence factor synthesis in response to physiological or environmental changes.

Prader-Willi syndrome

People with Prader-Willi syndrome (PWS) and their families provide a unique challenge to the general practitioner. This article provides an outline of the key information and management issues for general practitioners who care for people with PWS and their families.

"Reduction" of CGG trinucleotide expansion from mother to offspring in seven fragile-X families

Apparent reduction in the size of the CGG repeat is reported from seven fragile-X mothers to nine offspring in seven extended families. The overall frequency of the reduction amongst 121 fragile-X mother-fragile-X child transmissions was 7.4%, compared with an 18% reduction in fragile-X father-fragile-X daughter transmissions, but ascertainment bias may account for some underestimation of the frequency of reductions, especially between mothers and their offspring. In one mother-son transmission, a premutation present in the son (with a full mutation present in the mother) was unmethylated. This may be the result of either demethylation with reduction, or undetected mosaicism in the mother. There was no obvious increase in the level of intellectual performance in female offspring who received a reduced fragment from their mothers. Several mechanisms leading to apparent reduction, such as germline mosaicism, deletion or replication slippage, should be considered.