The impact of social determinants on health outcomes in a region in the North of England: a structural equation modelling analysis

OBJECTIVES

The aim of this study was to identify the impact of social determinants of health on physical and mental health outcomes in a UK population.

STUDY DESIGN

Structural equation modelling was used to hypothesise a model of relationships between health determinants and outcomes within a region in the North of England using large-scale population survey data (6208 responses).

METHODS

We analysed responses from a population survey to assess the influence of a deprivation-based index at the environmental level, education and income on a behaviour index (smoking, alcohol consumption, physical activity, and dietary habits) and the influence of all these factors on self-reported physical health and the influence of the behaviour index and income on mental wellbeing.

RESULTS

The proposed model was well supported by the data. Goodness-of-fit statistics, most notably a low value of the root mean square error of approximation (RMSEA), supported the validity of the proposed relationships (RMSEA = 0.054). The model revealed all examined paths to be statistically significant. Income and education were influential in determining an individual's behaviour index score, which, with income was the most important predictor of both the correlated outcomes of physical health and mental wellbeing (P < 0.001 in all cases).

CONCLUSIONS

Findings challenge the traditional view of singular causal pathways, emphasising that interventions should consider the underlying influencing socio-economic conditions, which would influence behaviour and therefore physical and mental wellbeing. The extent to which the model is supported by the data, and the statistical significance of individual relationships accentuates the imperative for comprehensive public health strategies that integrate multiple socio-economic factors.

Radiation protection measures used in Portuguese interventional radiology departments: A national survey

INTRODUCTION

This study aimed to characterise radiation protection (RP) measures used in interventional radiology (IR) departments in Portugal with respect to European and national recommendations.

METHODS

An online national survey was created to characterise the fluoroscopy technology as well as analyse the frequency of body fluoroscopy-guided intervention procedures (FGIP), RP education and training of the staff, and RP measures used daily.

RESULTS

In Portugal, most equipment for FGIP are single-sourced and have a flat panel detector (70%). The most commonly FGIP are percutaneous biliary drainage, percutaneous arterial and venous thrombolysis/thrombectomy, arteriovenous malformations embolization, and percutaneous transluminal balloon angioplasty for arteriovenous fistulas. Only a few staff members had received postgraduate education and training in RP (30%), with most nurses having not received RP education and training (40%). Some of the recommended RP measures lacked harmonisation. Additionally, >50% of the IR departments do not consider examination dose values to identify patients eligible for tissue reactions follow-up.

CONCLUSION

This is the first study to examine the characteristics of IR departments in Portugal. We observed a lack of RP education and training among staff members; further, there was a need to update some RP measures in some IR departments according to the recommendations.

IMPLICATIONS FOR PRACTICE

Our findings will be presented to the participating IR departments in order to update and promote RP best practices. Moreover, our findings will be presented to the national societies of the different professional groups in order to inform strategies for harmonising RP education and training of the staff.

POS0908 AUDIOLOGICAL DISTURBANCES IN PATIENTS WITH SYSTEMIC SCLEROSIS: ASSOCIATION WITH CLINICAL MANIFESTATIONS AND NAILFOLD CAPILLARY MICROSCOPIC ABNORMALITIES

Background

Systemic Sclerosis (SSc) is a rare connective tissue disease with several systemic and organ specific manifestations, characterized by immune dysfunction, vascular abnormalities, and fibrosis. The microvascular damage is a prominent feature of SSc, being easily assessed by nailfold video-capillaroscopy (NVC). These vascular changes may result in the involvement of the inner ear as the cochlea is highly sensitive to these changes. Blood changes and hypoxia seem to culminate with necrosis of the cochlear tissue, which is clinically expressed as hypoacusis and tinnitus. Hearing loss and auditory symptoms have been reported in 20 to 40% of SSc patients. The prominence of other symptoms may be a reason for audiovestibular symptoms being neglected in these patients, but this can negatively affect patient’s quality of life (QoL) and social interaction.

Objectives

The aim of this study is to assess the prevalence of audiological disturbances in patients with SSc and to evaluate its relationship with the duration, characteristics, and severity of the disease.

Methods

Cross-sectional study included 24 patients with SSc, who fulfilled ACR/EULAR criteria followed at outpatient rheumatology clinic between 2012 and 2020 and 20 healthy controls. Socio-demographic, clinical data and pattern of NVC were collected. Both groups underwent a complete ear-nose-throat physical examination, pure-tone audiometry, speech audiometry and impedance. QoL was assessed by the European Quality of Life–5 Dimensions (EQ-5D) questionnaire. Descriptive analysis was performed, p-value <0.05 was statistically significant.

Results

Clinical characteristics and audiometric findings of all patients are listed in Table 1. 13% of patients with SSc reported hearing loss and 38% reported tinnitus and vertigo. Similar values were reported in control group with exception to vertigo symptoms (20%). 37.5% patients presented abnormal hearing loss in the pure-tone audiometry compared with 5% of the controls (p=0.02). Sensorineural hearing loss and abnormal speech reception threshold were more common in SSc patients compared to controls (p=0.03; p=0.04). Auditory recruitment was found in 1 SSc patient. There was no correlation between objective hearing loss and type of scleroderma, duration of disease, type of antibodies, skin score, NVC patterns and organ involvement but there were statistically significant differences with history of digital ulcers. We also found middle ear dysfunction: absence of stapedius reflex (20.8%) and abnormal tympanometry (45.8%) in patients with SSc versus control group (p=0.001). The mean value of EQ-VAS was lower in SSc group (63.8±13.1) compared to controls (71.1±11.0) (p=0.04), but without significant differences with the changes in the pure-tone or speech audiometry.

Table 1.

Clinical characteristics and audiometric findings of all patients

SSc n=24Controls n=20pAge, years (mean±SD)58.4±11.455.3±10.30.63Sex (M/F), n5/196/140.49Duration disease (mean±SD)50.3±41.2-Diffuse cutaneous, n (%)7 (29.2)-Anti-Scl70 antibody, n (%)6 (25.0)-Anticentromere antibody, n (%)14 (58.3)-Anti-RNA polymerase III antibody, n (%)3 (12.5)-Pulmonary involvement, n (%)7 (29.2)-Gastrointestinal involvement, n (%)8 (33.3)-Articular involvement, n (%)2 (8.3)-Nailfold video-capillaroscopy pattern-- Nonspecific1 (4.2) Early11 (45.8) Active8 (33.3) Late4 (16.7)Subjective hearing loss, n (%)3 (12.5)3 (15)0.58Tinnitus, n (%)9 (37.5)4 (20)0.41Objective hearing loss, n (%)9 (37.5)1 (5)0.02Sensorineural hearing loss (%)7 (29.2)1 (5)0.03EQ-VAS (mean±SD)63.8±13.171.1±11.00.04

Conclusion

Our study found higher prevalence of inner and middle ear pathologies in SSc patients. It is also important to emphasize the relationship found with history of digital ulcer. In these patients, this type of involvement should be considered both during diagnostic and therapeutic procedures. Further investigation is needed for a better understanding of ear damage in these patients.

Disclosure of Interests

None declared

Assessing the effects of PMM2 variants on protein stability

Phosphomannomutase 2 deficiency, PMM2-CDG, is the most frequent disorder of protein N-glycosylation. It is an autosomal recessive disease with a broad clinical and biochemical phenotype. Trying to predict the impact of novel variants is often a challenge due to the high number of variants and the difficulty to establish solid genotype-phenotype correlations. A potential useful strategy is to use computational chemistry calculations as a tool from which relevant information on the structural impact of novel variants may be deduced. Here we present our analyses based on four well-known PMM2 deleterious variants (p.(Leu32Arg), p.(Asp65Tyr), p.(Phe119Leu), p.(Arg141His)) and the polymorphic p.(Glu197Ala) for which we have predicted the effect on protein stability. Our work predicts the effect of different amino acid residues on the conformation and stability of PMM2. These computational simulations are, therefore, an extremely useful methodology which, in combination with routinely used in silico methods of pathogenicity prediction, may help to reveal the structural impact of novel variants at the protein level, potentially leading to a better understanding of target biological molecules.

Quality by design (QbD) optimization of diazepam-loaded nanostructured lipid carriers (NLC) for nose-to-brain delivery: Toxicological effect of surface charge on human neuronal cells

Diazepam is commonly used in the management of epileptic seizures, although it has limitations that can be overcome by using formulations that are easier to administer and capable of directing the drug to the brain. In this field, it has been reported that the use of nanostructured lipid carriers (NLC) via intranasal (or via nose-to-brain) promotes the targeting of drugs to the brain, improving the effectiveness of therapy. The aim of this work was to optimize two diazepam-loaded NLC formulations for nose-to-brain delivery, one with positive surface charge and one with negative surface charge. The quality by design (QbD) approach was used to design the experiments, where the quality target product profile (QTPP), the risk assessment and the critical quality attributes (CQAs) were defined to ensure safety, efficacy and quality of the final formulations. The experiments started with the optimization of critical material attributes (CMAs), related to the ratios of lipids and emulsifiers, followed by the selection of critical process parameters (CPPs), related to the production methods of the diazepam-loaded NLC formulation (ultrasound technique and high-pressure homogenization - HPH). Afterwards, the positive surface charge of the diazepam-loaded NLC was optimized. Finally, the biocompatibility with human neuronal cells of the formulation with a negative surface charge and of the formulation with a positive surface charge was evaluated. The results of the optimization of the CMAs showed that the ratios of lipids and emulsifiers more adequate were 6.7:2.9 and 4.2:0.3 (% w,w), respectively. Regarding the CPPs, HPH was considered the most suitable production method, resulting in an optimized diazepam-loaded NLC formulation (F1C15) with negative surface charge, showing particle size of 69.59 ± 0.22 nm, polydispersity index (PDI) of 0.19 ± 0.00, zeta potential (ZP) of -23.50 ± 0.24 mV and encapsulation efficiency (EE) of 96.60 ± 0.03 %. The optimized diazepam-loaded NLC formulation (F2A8) with positive surface charge had particle size of 124.40 ± 0.84 nm, PDI of 0.17 ± 0.01, ZP of 32.60 ± 1.13 mV and EE of 95.76 ± 0.24 %. In addition, the incorporation of diazepam in NLC resulted in a sustained release of the drug. No significant changes in particle size, PDI, ZP and EE were observed for the formulation F1C15, after 3 months of storage, whereas for formulation F2A8, particle size increased significantly. Biocompatibility studies showed that the formulation F2A8 was more cytotoxic than the formulation F1C15. Thereby, we conclude that the formulation F1C15 is more suitable for targeting the brain, when compared with the formulation F2A8. From the results of these studies, it can be confirmed that the QbD approach is an adequate and central tool to optimize NLC formulations.

Spatially variable pesticide application in olive groves: Evaluation of potential pesticide-savings through stochastic spatial simulation algorithms

Site-specific management using spatial crown volume characterization can greatly reduce the amount of pesticides applied in agricultural treatments performed with air-assisted sprayers, while helping farmers achieve the European legislation on safe use of pesticides. Nevertheless, variable rate treatments in olive groves have received little attention. Thus, field research was conducted in a 20.6-ha traditional olive grove. Two attributes of the trees - tree crown volume (V) and tree projected area - were determined, using 67 samples for V and all trees of the field (1433) for tree projected area. Spatial continuity of both attributes was modelled with exponential variograms. To gain a measure of local uncertainty, stochastic simulation algorithms were applied. One hundred simulated images were obtained for tree projected area using direct sequential simulation. Tree projected area simulations were used to improve spatial prediction of V, more difficult and more expensive to obtain, taking advantage of the high linear correlation between both variables (r_xy = 0.72,p < 0.001). Thus, direct sequential cosimulation was employed to predict the spatial distribution of V, obtaining 100 geostatistical realizations of V. In order to estimate the potential reduction of pesticide use in the farm with variable rate treatments, two cut-off values of V were considered (50 and 100 m³_{crown volume}). Local uncertainty, understood as the probability of each tree belonging to a given crown volume interval was determined. Probability maps were further transformed to morphological maps and finally to variable prescription maps. Two scenarios with 2 and 3 management zones (MZs) were obtained. In comparison with a conventional phytosanitary application, the variable rate treatments could reduce the pesticide amounts by 21.3% with 2 MZs, and by 38% with 3 MZs. The joint use of V and tree projected area in stochastic sequential simulation algorithms has shown to be useful to determine MZs in olive groves.

Blood pressure lowering treatment for prevention of cardiovascular events in patients with atrial fibrillation: an individual-participant data meta-analysis

Background

Randomised evidence showing that pharmacological blood pressure (BP) lowering can reduce cardiovascular risk of patients with atrial fibrillation (AF) is limited.

Purpose

This study aimed to compare the effect of BP-lowering treatment on fatal and non-fatal cardiovascular outcomes in patients with and without AF overall and by major drug classes.

Methods

We extracted individual participant data from all trials with over 1,000 person-years of follow-up that had randomly assigned patients to different classes of BP-lowering drugs, BP-lowering drugs vs placebo, or to more vs less intensive BP-lowering regimens. We investigated the effects of BP-lowering treatment on a composite endpoint of major cardiovascular events (stroke, ischaemic heart disease or heart failure) according to AF status at baseline using fixed-effect one-stage individual participant data meta-analyses based on Cox proportional hazards models stratified by trial.

Findings

Twenty-two trials were included with 188,570 patients, of whom 13,266 (7%) had AF at baseline. Patients with AF had lower BP at baseline than patients without AF (143/84 mmHg, SD 21/12mmHg) versus 155/88 mmHg, SD 21/13 mmHg, respectively). Meta-regression showed that relative risk reductions were proportional to trial-level intensity of BP lowering, both in patients with and without AF. The hazard ratio for major cardiovascular events was 0.91 in patients with AF (95% confidence interval [0.83–1.00]) and 0.91 without AF (95% confidence interval [0.88–0.93]) for each 5-mmHg reduction in systolic BP, with no difference between subgroups (p=0.91) (Figure 1). Similar patterns were observed for individual components of the composite primary outcome. In patients with AF, there was no evidence that treatment effects varied according to baseline systolic BP or use of specific drug classes.

Conclusion

This study demonstrated that BP-lowering treatment reduces the risk of major cardiovascular events in patients with AF to a similar extent to that of patients without AF, even when baseline BP is below recommended treatment thresholds. Owing to their higher absolute cardiovascular risk, treatment in patients with AF is likely to result in greater absolute risk reduction than in patients without AF. Guidelines should be updated to clearly recommend pharmacological BP lowering for prevention of cardiovascular events in patients with AF.

Figure 1. Forest plot

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Effect of blood pressure lowering treatment on the risk of atrial fibrillation: an individual-participant data meta-analysis

Background

Although observational studies have suggested an association between elevated blood pressure (BP) and increased risk of atrial fibrillation (AF), randomised evidence on the effects of pharmacological blood pressure lowering on the risk of new-onset AF remains limited.

Purpose

To investigate the effects of pharmacological BP lowering on the risk of AF overall and stratified by baseline risk of AF and by drug class.

Methods

We extracted individual participant data from trials with over 1,000 person-years of follow-up that had randomly assigned patients to different classes of BP-lowering drugs, BP-lowering drugs vs placebo, or to more vs less intensive BP-lowering regimens. We investigated the effects of BP lowering on the risk of new-onset AF using fixed-effect one-stage individual participant data meta-analyses based on Cox proportional hazards models stratified by trial.

Results

Twenty-one trials were included with a total of 194,041 patients, in whom 6,357 new-onset and 516 recurrent AF events were recorded. The hazard ratio for new-onset AF was 1.01, 95% CI [0.95–1.07] per each 5-mmHg reduction in systolic BP, and meta-regression suggested that treatment effects were similar irrespective of the intensity of systolic BP reduction. Patients were overall at low risk of AF at baseline (median 2.3%, IQR [1.2–3.4%] at 5 years), and there was no evidence of heterogeneity in treatment effects across thirds of risk and 10-mmHg strata of baseline systolic BP (Figure). There was also no clear evidence that treatment effects differed between drug classes when renin-angiotensin-aldosterone system inhibitors and calcium channel blockers were compared with placebo and/or standard treatment.

Conclusion

In a low-risk population, pharmacological BP lowering did not reduce the risk of new-onset AF. Further research is needed to understand whether the effects would be different in high-risk individuals, and to better clarify the existence of class-specific effects.

Figure 1. Forest plot

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

P5732Effects of blood pressure lowering drugs in heart failure: a systematic review and meta-analysis of randomised controlled trials

Background

Observational studies have reported a J-shaped relationship between blood pressure (BP) and all-cause and cardiovascular mortality in patients with heart failure (HF). Although decreasing BP significantly reduces the risk of fatal and non-fatal cardiovascular outcomes in the general population across a range of baseline BP categories, the extent to which those findings are applicable to HF patients and whether the relationship holds true when baseline BP is very low remain unclear. Therefore, it is yet to be established whether the observed J-shaped relationship between BP and clinical outcomes in patients with HF is causal and/or modified by antihypertensive treatment.

Purpose

We aimed to combine evidence from all HF trials that have investigated the effects of drugs with BP-lowering properties to assess (1) the extent to which such drugs reduce BP in HF, (2) the association between the net change in BP between treatment arms and cause-specific outcomes, and (3) whether treatment effects (including benefits and potential harms) vary according to baseline BP.

Methods

We conducted a systematic review and meta-analysis including randomised clinical trials of drugs with BP-lowering properties conducted in patients with chronic HF with at least 300 patient-years follow-up.

Results

We included a total of 37 trials (91,950 patients) and showed that treatment with drugs with BP-lowering properties significantly reduced SBP by 2.0 mmHg in all trials and by 2.4 mmHg in placebo-controlled trials (Figure 1). There was no evidence that BP reduction in placebo-controlled trials varied across strata of baseline BP, but there was suggestive evidence for differential effects by drug class, with renin-angiotensin-aldosterone system inhibitors reducing SBP by 3.2 mmHg (95% CI [−4.0, −2.4]), whilst BB appeared to have a neutral effect on BP. There was no evidence that the relative risk reduction afforded by treatment with BP-lowering drugs on all-cause mortality, cardiovascular mortality and HF hospitalisation was significantly different across categories of baseline BP. There was also no strong evidence for heterogeneity of treatment effect on adverse events leading to treatment discontinuation by baseline BP. Meta-regression did not show significant associations between the magnitude of BP reduction achieved in each trial and risk of those clinical outcomes.

Figure 1

Conclusions

Treatment with drugs with BP-lowering properties resulted in a small but significant decrease in SBP in patients with HF irrespective of baseline BP. There was no evidence that the effects of those drugs differed across the range of baseline SBP, thus supporting the efficacy and safety of those drugs in patients with low baseline BP. Data from published reports was insufficient to adequately investigate whether BP-dependent mechanisms contribute to the effect of BP-lowering drugs on clinical outcomes in patients with HF.

Acknowledgement/Funding

None

RFT1-CDG: Absence of Epilepsy and Deafness in Two Patients with Novel Pathogenic Variants

This report is on two novel patients with RFT1-CDG. Their phenotype is characterized by mild psychomotor disability, behavioral problems, ataxia, and mild dysmorphism. Neither of them shows signs of epilepsy, which was observed in all RFT1-CDG patients reported to date (n = 14). Also, deafness, which is often associated with this condition, was not observed in our patients. Molecular analysis of RFT1 showed biallelic missense variants including three novel ones: c.827G > A (p.G276D), c.73C > T (p.R25W), and c.208T > C (p.C70R).

The impact of laboratory chow for rats in the experiments: Chemical and biological evaluation of nine grain-based diet options

Cereal-based diets formulated as semi-purified diets can provide flexibility for researchers, enabling open controlled formulas, besides being cheaper than purified diets. Seeking to widen the researchers’ options in their experimental design developments, we aimed at assaying the chemical score, growth performance and protein utilization of nine semi-purified experimental chows. These diets were formulated at 17.8%, 12% and 8% protein contents, using three variations of ingredients for each one, as follows: casein (C), casein+soybean meal (C+S, 1:1 w/w protein) and casein+soybean meal+corn gluten meal (C+S+G, 1:1:1 w/w protein), without cysteine supplementation and setting casein 17.8% (AIN-93G) as reference diet. The diets C and C+S (17.8%) had the Cys as the limiting amino acid once the addition of gluten turns the Lys as second limiting. All diets had the potential for promoting growth with body mass gain, feed conversion ratio (FCR; chow consumed per body weight gain, average 3.12) and feed efficiency ratio (FER; body weight gain per chow consumed, average 0.3), except for C+S+G 8% (FCR = 6 g; FER = 0.13). These variations were mainly due to the protein amounts independently from the protein ingredient used and could characterize the C+S+G 8% as unable to support growth. For the other parameters (digestibility, net protein ratio, net protein utilization and protein efficiency ratio), there were no relevant differences between the diets. We can conclude that 17.8%, 12% and 8% chows (C and C+S) allowed a proper combination of ingredients from the point of view of palatability, nutrient availability/utilization, metabolic processes, growth performance and feed utilization parameters.

Validation of a questionnaire (CARAT10) to assess rhinitis and asthma in patients with asthma

BACKGROUND AND AIM

The Control of Allergic Rhinitis and Asthma Test (CARAT) was developed to be used in the concurrent management of these diseases, as recommended by the Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines. However, it was necessary to statistically identify and remove redundant questions and to evaluate the new version's factor structure, internal consistency and concurrent validity.

METHODS

In this cross-sectional study 193 adults with allergic rhinitis and asthma from 15 outpatient clinics in Portugal were included. The CARAT questionnaire was reduced using descriptive analysis, exploratory factor analysis and internal consistency. Spearman's correlations were used to compare the CARAT scores with a medical evaluation and other measures of control, including the Asthma Control Questionnaire and symptoms' visual analogue scales. The performance against physician rating of control was summarized using the area under the curve (AUC) from receiver operating characteristic analysis. In addition, CARAT was compared with the physician's decision to reduce, maintain or increase treatment.

RESULTS

The reduced version has 10 questions and 2 factors (CARAT10). The Cronbach's alpha was 0.85. All correlation coefficients of CARAT10 and factors with the different measures of control met the a priori predictions, ranging from 0.58 to 0.79. The AUC was 0.82. For the physician's decision groups of reduce, maintain or increase treatment, the mean (IC95%) scores of CARAT10 were 24 (21.4;26.6), 21 (19.4;21.9) and 15 (13.6;16.5), respectively.

CONCLUSION

CARAT10 has high internal consistency and good concurrent validity, making it useful to compare groups in clinical studies.

Molecular mechanisms underlying large genomic deletions in ornithine transcarbamylase (OTC) gene

Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle error causing hyperammonemia and orotic aciduria. Clinical diagnosis is generally confirmed by mutation detection. However, in approximately 20% of the patients, no mutation is found by conventional mutation-searching strategies, which fail to detect deletions spanning at least a whole exon, large rearrangements, or mutations at non-coding regions. To detect large deletions or duplications, we have applied the multiplex ligation-dependent probe amplification (MLPA) methodology to three OTCD patients (two females and one male). MLPA revealed copy number alterations of OTC exons in all of them. The two females were found to be heterozygous for deletions of either exon 2 or exons 6-9, and the male was confirmed to lack all OTC exons. Females' characterization of the deletion breakpoints by long polymerase chain reaction and sequencing revealed the mutations c.78-3544_217-129del5921 and c.541-600_1005 + 1880del10862 corresponding to exon 2 and exon 6-9 deletions, respectively. Examination of the deletion-flanking regions suggests that exon 2 deletion probably resulted from replication slippage facilitated by a secondary structure formed by two inverted Alu repeats, whereas an Alu-Alu homologous recombination was probably responsible for the exon 6-9 deletion. This work contributes to the identification of novel disease-causing mutations in OTCD and increases the knowledge on possible mutational mechanisms generating deletions in OTC.

Congenital Disorder of Glycosylation Type Ia: Searching for the Origin of Common Mutations inPMM2

Congenital Disorders of Glycosylation (CDG) are a group of recessive genetic disorders characterized by hypoglycosylation of glycoproteins. CDG-Ia, the most common type, is caused by mutations in the PMM2 gene, coding for a phosphomannomutase (PMM2; EC 5.4.2.8). The mutational spectrum of PMM2 comprises more than 80 different mutations but one of them, R141H, is particularly interesting due to its high frequency among CDG-Ia patients worldwide. In contrast, other mutations are ethnically or geographically restricted, such as D65Y which is only found in patients of Iberian ancestry. In the present study a population genetic approach was used in an attempt to clarify the origins of two important disease causing mutations: R141H and D65Y. Based on SNP and STR genotypic analysis, we ascertained an association between the R141H substitution and a particular haplotype, suggesting a common origin for all the mutated chromosomes. Similar results were found for D65Y, although the associated haplotype was different from that of R141H, suggesting independent origins for these two mutations. Our results enable us to infer an Iberian origin for the D65Y mutation.

Mutational Spectrum and Linkage Disequilibrium Patterns at the Ornithine Transcarbamylase Gene (OTC)

Ornithine transcarbamylase (OTC; EC 2.1.3.3) is a hepatic enzyme involved in ammonia elimination via the urea cycle. Since the sequence of the OTC gene was reported many types of mutations continue to be found in OTC deficiency patients, continuing to increase the already wide mutational spectrum known for this gene. In this study we present the clinical, biochemical and molecular features of thirteen late-onset OTC deficiency patients. Mutations were identified in all these patients, among which six were novel point substitutions (L59R, A137P, L148S, Y176L, L186P, and K210N) and one was a 2-bp deletion at exon 4 (341-342delAA). In addition, a de novo genomic deletion of maternal origin encompassing exons 1 to 5 was also identified by the analysis of LD patterns using intragenic polymorphic markers. This work exemplifies the potential value of population genetic studies for the detection of large deletions.

Doença de Dupuytren. Revisão de 100 doentes operados

A Doença de Dupuytren observa-se com frequência nesta região. Dada a sua incidência, a diminuição da capacidade de trabalho que pode provocar e o elevado número de casos tratados cirurgicamente, decidimos reavaliar os pacientes, tentando identificar factores etiológicos e o resultado do tratamento.

Foi efectuado um estudo de revisão clínico e de registos em processo de 100 casos, operados entre Fevereiro de 2002 e Dezembro de 2005 no Serviço de Ortopedia do Hospital do Vale do Sousa.

Após discussão com os ortopedistas assistentes, todos os dados relevantes recolhidos foram tratados estatisticamente em colaboração com o Serviço de Bioestatística da Faculdade de Medicina do Porto.

Os resultados são precedidos de uma perspectiva histórica e um sumário da etiologia, evolução, estadiamento, classificação e opções de tratamento da doença de Dupuytren.

Novel L2HGDH mutations in 21 patients with L-2-hydroxyglutaric aciduria of Portuguese origin

We studied 21 patients, from 18 families, with L-2-hydroxyglutaric aciduria (L-2-HGA), a rare neurometabolic disorder with a homogeneous presentation: progressive neurodegeneration with extrapyramidal and cerebellar signs, seizures, and subcortical leukoencephalopathy. Increased levels of L-2-hydroxyglutaric acid in body fluids proved the diagnosis of L-2-HGA in all 21 patients. We analyzed the L-2-HGA gene (L2HGDH), recently found to be mutated in consanguineous families with L-2-HGA, and identified seven novel mutations in 15 families. Three mutations appeared to be particularly prevalent in this Portuguese panel: a frameshift mutation (c.529delC) was detected in 12 out of 30 mutant alleles (40%), a nonsense mutation (c.208C>T; p.Arg70X) in 7/30 alleles (23%), and a missense mutation (c.293A>G; p.His98Arg) in four out of 30 mutant alleles (13%), suggesting that common origin may exist. Furthermore, two novel missense (c.169G>A; p.Gly57Arg, c.1301A>C; p.His434Pro) and two splice error (c.257-2A>G, c.907-2A>G) mutations were found. All the mutations presumably lead to loss-of-function with no relationship between clinical signs, progression of the disease, levels of L-2-HGA and site of the mutation. In the three remaining families, no pathogenic mutations in the L-2-HGA were found, which suggests either alterations in regulatory regions of the gene or of its intervening sequences, compound heterozygosity for large genomic deletion and, or further genetic heterogeneity.

Black bean (Phaseolus vulgaris L.) as a protective agent against DNA damage in mice

This study was designed to evaluate the toxicogenetic or protective effect of cooked and dehydrated black beans (Phaseolus vulgaris L.) in bone marrow and peripheral blood cells of exposed mice. The frequency of micronuclei detected using the bone marrow erythrocyte micronucleus test and level of DNA lesions detected by the comet assay were chosen as end-points reflecting mutagenic and genotoxic damage, respectively. Initially, Swiss male mice were fed with a 20% black bean diet in order to detect mutagenic and genotoxic activity. However, no increase in the frequency of bone marrow micronucleated polychromatic erythrocytes (MN PCEs) or DNA lesion in leukocytes was observed. In contrast, received diets containing 1, 10 or 20% of black beans, a clear, but not dose-dependent reduction in the frequency of MN PCEs were observed in animals simultaneously treated with cyclophosphamide, an indirect acting mutagen. Similar results were observed in leukocytes by the comet assay. Commercial anthocyanin was also tested in an attempt to identify the bean components responsible for this protective effect. However, instead of being protective, the flavonoid, at the highest dose administered (50 mg/kg bw), induced primary DNA lesion, as detected by the comet assay. These data indicate the importance of food components in preventing genetic damage induced by chemical mutagens, and also reinforce the role of toxicogenetic techniques in protecting human health.

Study on the mutagenicity and antimutagenicity of a natural food colour (annatto) in mouse bone marrow cells

Most manufactured foods contain chemicals added as a deliberate part of the manufacturing process. The aims of the present study were to evaluate the mutagenicity and antimutagenicity of annatto, a natural pigment extracted from the Bixa orellana L. and widely used as a colorant in foods. The micronucleus test was performed in bone marrow cells from Swiss male mice treated with one of the three concentrations of annatto (1330, 5330 and 10,670 ppm), incorporated into the diet. The animals were fed with the diets for 7 days and sacrificed 24 h after the last treatment. For the evaluation of the antimutagenic potential of annatto, at day 7, the animals received an intraperitoneal injection of cyclophosphamide (50 mg/kg body weight). Under the concentrations tested annatto did not present mutagenic or antimutagenic activities on the mice bone marrow cells. However, an increased frequency of micronucleated cells was observed when the highest concentration (10,670 ppm) was administered simultaneously with cyclophosphamide. In conclusion, the data indicate that annatto colour, for the conditions used, is neither mutagenic nor an inhibitor of induced mutations, although it should be used carefully since high doses may increase the effect of a mutagen.

Haplotype analysis and phylogeny of ornithine transcarbamylase polymorphisms

Ornithine transcarbamylase (OT2, EC 2.1.3.3) deficiency, the most common inborn error of urea cycle, is caused by a vast number of point mutations, deletions and insertions in the respective gene. Furthermore, 12 single nucleotide polymorphisms (NSPs) have been described in the OTC gene, four of them causing an amino acid change. We have studied the frequency of these markers in two populations: Portuguese and Mozambican. No significant differences were observed between populations, except for Lys --> Arg in codon 46. Allelic associations between polymorphisms were used to define haplotypic patterns. The three common haplotypes (H1, H2 and H3) show a combined frequency of 95% in Portugal and 87% in Mozambique. One haplotype was found only in Portugal and three are only present in Mozambique, resulting in a higher haplotype diversity. The combined information from the SNPs and the DXS1068 (CA)n repeat was used to outline OTC haplotype phylogeny, which, in conjunction with the population data, allowed us to sketch possible evolutionary pathways although some haplotypes could have arisen by either repeated mutation or recombination.