Imaging in osteogenesis imperfecta: Where we are and where we are going

Osteogenesis imperfecta (OI) is a rare phenotypically and genetically heterogeneous group of inherited skeletal dysplasias. The hallmark features of OI include bone fragility and susceptibility to fractures, bone deformity, and diminished growth, along with a plethora of associated secondary features (both skeletal and extraskeletal). The diagnosis of OI is currently made on clinical grounds and may be confirmed by genetic testing. However, imaging remains pivotal in the evaluation of this disease. The aim of this article is to review the current role played by the various radiologic techniques in the diagnosis and monitoring of OI in the postnatal setting as well as to discuss recent advances and future perspectives in OI imaging. Conventional Radiography and Dual-energy X-ray Absorptiometry (DXA) are currently the two most used imaging modalities in OI. The cardinal radiographic features of OI include generalized osteopenia/osteoporosis, bone deformities, and fractures. DXA is currently the most available technique to assess Bone Mineral Density (BMD), specifically areal BMD (aBMD). However, DXA has important limitations and cannot fully characterize bone fragility in OI based on aBMD. Novel DXA-derived parameters, such as Trabecular Bone Score (TBS), may provide further insight into skeletal changes induced by OI, but evidence is still limited. Techniques like Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) can be useful as problem-solvers or in specific settings, including the evaluation of cranio-cervical abnormalities. Recent evidence supports the use of High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) as a promising tool to improve the characterization of bone fragility in OI. However, HR-pQCT remains a primarily research technique at present. Quantitative Computed Tomography (QCT) is an alternative to DXA for the determination of BMD at central sites, with distinct advantages but considerably higher radiation exposure. Quantitative Ultrasound (QUS) is a portable, inexpensive, and radiation-free modality that may complement DXA evaluation, providing information on bone quality. However, evidence of usefulness of QUS in OI is poor. Radiofrequency Echographic Multi Spectrometry (REMS) is an emerging non-ionizing imaging method that holds promise for the diagnosis of low BMD and for the prediction of fracture risk, but so far only one published study has investigated its role in OI. To conclude, several different radiologic techniques have proven to be effective in the diagnosis and monitoring of OI, each with their own specificities and peculiarities. Clinicians should be aware of the strategic role of the various modalities in the different phases of the patient care process. In this scenario, the development of international guidelines including recommendations on the role of imaging in the diagnosis and monitoring of OI, accompanied by continuous active research in the field, could significantly improve the standardization of patient care.

Antarctic permafrost degassing in Taylor Valley by extensive soil gas investigation

Ongoing studies conducted in northern polar regions reveal that permafrost stability plays a key role in the modern carbon cycle as it potentially stores considerable quantities of greenhouse gases. Rapid and recent warming of the Arctic permafrost is resulting in significant greenhouse gas emissions, both from physical and microbial processes. The potential impact of greenhouse gas release from the Antarctic region has not, to date, been investigated. In Antarctica, the McMurdo Dry Valleys comprise 10 % of the ice-free soil surface areas in Antarctica and like the northern polar regions are also warming albeit at a slower rate. The work presented herein examines a comprehensive sample suite of soil gas (e.g., CO₂, CH₄ and He) concentrations and CO₂ flux measurements conducted in Taylor Valley during austral summer 2019/2020. Analytical results reveal the presence of significant concentrations of CO₂, CH₄ and He (up to 3.44 vol%, 18,447 ppmv and 6.49 ppmv, respectively) at the base of the active layer. When compared with the few previously obtained measurements, we observe increased CO₂ flux rates (estimated CO₂ emissions in the study area of 21.6 km² ≈ 15 tons day^-1). We suggest that the gas source is connected with the deep brines migrating from inland (potentially from beneath the Antarctic Ice Sheet) towards the coast beneath the permafrost layer. These data provide a baseline for future investigations aimed at monitoring the changing rate of greenhouse gas emissions from Antarctic permafrost, and the potential origin of gases, as the southern polar region warms.

Family Pediatrician and Public Health collaboration, an alliance to increase vaccination coverage: an experience with MenB vaccination in Italy

BACKGROUND

Invasive Meningococcal Disease is a severe disease mainly affecting infants and young children. Most infections are caused by serogroups A, B, C, W, X, and Y. In the last 10 years, serogroup B has been the main cause of Invasive Meningococcal Disease in Europe. Recent data resulting from an observational study conducted in Italy show a significant reduction in the number of Invasive Meningococcal Disease cases due to Neisseria meningitidis B after the introduction of vaccine 4CMenB. Thus, the Naples Team of Federation of Italian Primary Care Pediatricians and the Public Health Department started an active collaboration focused on vaccination process management (named "Progetto Via") with the aim of increasing Meningococcal B vaccination coverage.

STUDY DESIGN

Source of data is the regional platform "GE.VA.". Every Primary care Pediatrician uses daily to record vaccination activity. This platform is integrated with data entered by operators of the District/Vaccination Center.

METHODS

Time: January 2019 - December 2019. The Federation of Italian Primary Care Pediatricians/Naples organized a meeting to identify six coordinators. The pediatricians could choose to counsel in their own offices and send children to the vaccination center or to counsel and vaccinate directly in their own clinics.

RESULTS

A total of 78 pediatricians took part in the project: 46 did only counseling and 32 did both counseling and vaccination in their medical clinic. Data obtained show an overall average vaccination coverage growth of about 13% in the first 4 months of the survey, and a further growth of about 11% in the following seven months, with a total growth in the entire period of 24%. The pediatricians' counseling is essential to recover non-compliant subjects, considering both the relationship of trust with the families and the visits already scheduled as an ideal moment for vaccinations' status check.

CONCLUSIONS

The project highlights how an effective collaboration between family pediatricians and the Local Health Authority becomes valuable in getting closer to reach the Ministerial goal of 95%. Vaccination coverage increased significantly when family pediatricians supported the activity of vaccine centers in distress in many regional situations. The trust relationship, the hourly availability and the capillary network of family pediatricians' clinics were key elements for the success of this project and were also recognized by parents.

Non-Invasive Identification of Atrial Fibrillation Driver Location Using the 12-lead ECG: Pulmonary Vein Rotors vs. other Locations

Atrial fibrillation (AF) is an irregular heart rhythm due to disorganized atrial electrical activity, often sustained by rotational drivers called rotors. In the present work, we sought to characterize and discriminate whether simulated single stable rotors are located in the pulmonary veins (PVs) or not, only by using non-invasive signals (i.e., the 12-lead ECG). Several features have been extracted from the signals, such as Hjort descriptors, recurrence quantification analysis (RQA), and principal component analysis. All the extracted features have shown significant discriminatory power, with particular emphasis to the RQA parameters. A decision tree classifier achieved 98.48% accuracy, 83.33% sensitivity, and 100% specificity on simulated data.Clinical Relevance-This study might guide ablation procedures, suggesting doctors to proceed directly in some patients with a pulmonary veins isolation, and avoiding the prior use of an invasive atrial mapping system.

236Automatic classification of 20 different types of atrial tachycardia using 12-lead ECG signals

Funding Acknowledgements

Supported by the European Union"s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.766082 (MY-ATRIA)

Background

 Atrial Flutter (AFl) as a common reentrant atrial tachycardia is driven by self-sustainable mechanisms that cause excitation to propagate along pathways different from sinus rhythm. Intracardiac electrophysiological mapping and catheter ablation is often performed without prior knowledge of the mechanism perpetuating AFl in a given patient, likely prolonging the procedure time of these invasive interventions. We investigated the feasibility of automatically identifying 20 different AFl types based on the non-invasive 12-lead electrocardiogram (ECG) using machine learning. 

Methods

 Electrophysiological fast marching computer simulations of 20 different atrial tachycardia scenarios (micro-/macro-reentry, scar-related/anatomical/functional, figure-of-eight, focal, different locations) were performed and propagated to the standard 12-lead ECG based on the Courtemanche atrial action potential model. The virtual study population comprised combinations of 8 different anatomical bi-atrial models with 2 orientational variants each and 8 different torso models yielding a total of 2512 ECGs. From each ECG, we extracted 114 features from different domains (e.g., time, frequency, entropy, wavelet, non-linear recurrence analysis). The dataset was randomly split into 1256 training samples, 628 validation samples and 628 test samples while maintaining a balanced AFl type distribution. A radial basis neural network (RBNN) was trained as a classifier after selection of the most informative features. 

Results

The RBNN yielded a test set accuracy of 90% regarding the identification of the AFl mechanism using 10 features (from different domains). The most discriminative single feature was the cycle length that alone led to a test set accuracy of 74%, while the remaining feature set without cycle length (9 features) reduced the test set accuracy to 33%. The machine learning approach generalized well regarding unseen torso geometries (90% accuracy if training was performed on only 7 torso models) but rather poor regarding atrial anatomies (23% if the atrial anatomical model was not seen during training) indicating that more than the currently used 8 atrial models should be included during training to cover the relevant anatomical variability. 

Conclusions

Our results show that a machine learning classifier can potentially identify a high number of different AFl types using the 12-lead ECG. This non-invasive method can aid in planning and tailoring AFl treatment for patients. Application to clinical data is necessary as a next step to pave the way for clinical translation.

Abstract Figure.

Automated cortical thickness and skewness feature selection in bipolar disorder using a semi-supervised learning method

BACKGROUND

Bipolar disorder (BD) broadly affects brain structure, in particular areas involved in emotion processing and cognition. In the last years, the psychiatric field's interest in machine learning approaches has been steadily growing, thanks to the potentiality of automatically discriminating patients from healthy controls.

METHODS

In this work, we employed cortical thickness of 58 regions of interest obtained from magnetic resonance imaging scans of 41 BD patients and 34 healthy controls, to automatically identify the regions which are mostly involved with the disease. We used a semi-supervised method, addressing the criticisms on supervised methods, related to the fact that the diagnosis is not unaffected by uncertainty.

RESULTS

Our results confirm findings in previous studies, with a classification accuracy of about 75% when mean thickness and skewness of up to five regions are considered. We obtained that the parietal lobe and some areas in the temporal sulcus were the regions which were the most involved with BD.

LIMITATIONS

The major limitation of our work is the limited size or our dataset, but in line with other recent machine learning works in the field. Moreover, we considered chronic patients, whose brain characteristics may thus be affected.

CONCLUSIONS

The automatic selection of the brain regions most involved in BD may be of great importance when dealing with the pathogenesis of the disorder. Our method selected regions which are known to be involved with BD, indicating that damage to the identified areas can be considered as a marker of disease.

-643C > T RANKL gene polymorphism is associated with osteoporosis in Tunisian postmenopausal women

OBJECTIVES

The dynamic nature of the skeleton is achieved by a remodeling process. Receptor activator of nuclear factor kappa B (RANK) ligand (RANKL) stimulates bone resorption by activating RANK signaling. Therefore it is considered as a candidate gene regulating susceptibility to osteoporosis. In the current study, we have investigated the association between the RANKL gene -693G > C and -643 C > T polymorphisms and bone mineral density (BMD) in a population of postmenopausal Tunisian women.

METHODS

Polymorphic sites in RANKL gene (rs9533155 -693G > C and rs9533156 -643 C > T polymorphisms) were determined using PCR-RFLP analysis in 566 postmenopausal Tunisian women. All statistical analysis were examined by SPSS software.

RESULTS

We have detected a significant difference in lumbar spine and hip BMD for -643C > T genotypes. For -693G > C genotypes, a significant difference was detected only in hip BMD. The distribution of -643C > T genotypes and alleles between three groups (osteoporotic, osteopenic and normal women) revealed a significant association of the TT genotype with development of osteoporosis (p = 0.01; odds ratio 2.15), although for the -693G > C polymorphism, no significant results were found.

CONCLUSION

We have demonstrated the association of the -643C > T polymorphism with BMD variation and osteoporosis risk in postmenopausal Tunisian women.

Vitamin D levels and cytokine profiles in patients with systemic lupus erythematosus

OBJECTIVES

To evaluate the expression of Th1, Th2, and Th17 cytokines in patients with systemic lupus erythematosus (SLE), and verify the association between serum cytokine levels and vitamin D concentration.

METHODS

The sample consisted of 172 patients with SLE. 25-Hydroxyvitamin D (25(OH)D) levels were measured by chemiluminescence and 25(OH)D levels <20 ng/mL were considered to reflect vitamin D deficiency. Serum cytokine levels were measured in once-thawed samples, using a Th1/Th2/Th17 CBA (cytometric beads array) kit.

RESULTS

One hundred and sixty-one (93.6%) patients were women and 128 (74.4%) were of European descent. Mean patient age was 40.5 ± 13.8 years, and mean age at diagnosis was 31.5 ± 13.4 years. At the time of study entry, patients had a median (IQR) SLEDAI of 2 (1-4) and SLICC of 0 (0-1). Mean 25(OH)D concentration was 25.4 ± 11.04 ng/mL. Fifty-nine (34.3%) patients had a vitamin D deficiency. No statistically significant associations were identified between cytokine and vitamin D levels. The most significant finding was a positive correlation between INF-α levels and SLEDAI (r(s) = 0.22, p = 0.04).

CONCLUSION

Although vitamin D deficiencies are highly prevalent in patients with SLE, vitamin D levels were not significantly associated with patient cytokine profiles. The positive correlation between IFN-α levels and SLEDAI showed in this study corroborates other findings in the literature. The present results did not replicate those of in vitro studies of the effect of vitamin D levels on cytokine profiles. Placebo-controlled intervention trials of the effect of vitamin D on cytokine profiles are still required before any definitive conclusions can be drawn regarding the association between these variables.

Quantification of ventricular repolarization heterogeneity during moxifloxacin or sotalol administration using [Formula: see text]-index

Drug-induced alterations of ventricular heterogeneity must be limited to avoid induction of lethal ventricular arrhythmias. In here, a new parameter called [Formula: see text]-index, able to measure the standard deviation of myocites' repolarization times, was evaluated after moxifloxacin and sotalol administration. The two drugs are known to provide different alteration of the QT interval length ranging from subtle (moxifloxacin) to evident (sotalol). In fact, while the former is employed as active-comparator in thorough QT studies, the latter might induce torsades de pointes. 24 h Holter ECGs of 39 (sotalol) and 68 (moxifloxacin) healthy subjects were retrospectively analyzed. The recordings were performed after infusion of the drugs and after the placebo (moxifloxacin) or at baseline (sotalol). The corrected QT interval (QTc) was included as well in the study, for a direct comparison. In both populations, [Formula: see text]-index and QTc increased along with the drugs' serum concentration and were statistically different from values in the placebo arm or at baseline (p < 0.05).With sotalol, the maximum value of [Formula: see text]-index occurred, on average, after 5.64 h from the infusion, whereas for QTc after about 4.27 h. The two metrics displayed evident changes ([Formula: see text]-index: 27.79 ms ± 4.89 ms versus 60.13 ms ± 18.52 ms; QT corrected: 387.07 ms ± 19.84 ms versus 437.76 ± 32.05 ms; p < 0.05). Regarding moxifloxacin, maximum values were reached, on average, 5.01 h after administration for [Formula: see text]-index (30.70 ms ± 8.32 ms versus 40.48 ms ± 7.61 ms; p < 0.05), and 4.37 h for QTc (404.29 ms ± 29.05 ms versus 426.77 ± 36.67 ms; p < 0.05). They were statistically different from baseline values. With both drugs, the maximal percent variation after administration was higher for [Formula: see text]-index than QTc (moxifloxacin: 34.56% ± 24.60% versus 5.56% ± 2.98% ; sotalol: 114.77% ± 33.15% versus 12.13% ± 2.85% ; p < 0.05).The study suggests that the standard deviation of the ventricular repolarization times, as quantified by the [Formula: see text]-index, might be an effective measure of spatial heterogeneity.

Polymorphisms in VDR gene in Tunisian postmenopausal women are associated with osteopenia phenotype

OBJECTIVES

Osteopenia is characterized by intermediate values of bone mineral density (BMD) as compared to normal and osteoporotic subjects. BMD, a surrogate phenotype for osteoporosis, is influenced in part by genetic factors. Among the genes associated with BMD, the vitamin D receptor (VDR) was the first gene studied as a potential candidate associated with BMD in adult and postmenopausal bone loss. However, results are controversial.

METHODS

To determine whether VDR polymorphisms ApaI and TaqI are associated with BMD, osteopenia, osteoporosis and low-impact fracture risk in North Africans, these genotypes were analyzed in 566 postmenopausal Tunisian women.

RESULTS

In postmenopausal Tunisian women, the GT ApaI genotype seems to be protective against osteoporosis development (p = 0.02; odds ratio = 0.54). Moreover, the presence of the combined GT/TT genotype of ApaI and TaqI polymorphisms is more frequent in normal BMD women than in osteoporotic women (p = 0.00; odds ratio = 0.41). Interestingly, the GG ApaI genotype is associated with osteopenia development (p = 0.02; odds ratio = 1.86) and also the TT TaqI polymorphism (p = 0.02; odds ratio = 1.53). The GG ApaI genotype is associated with a three times risk of vertebral fracture.

CONCLUSIONS

The ApaI polymorphism showed an association with osteopenia and low-impact vertebral fracture incidence but not with osteoporosis. The TaqI polymorphism is associated specifically with the osteopenia phenotype. The presence of the two polymorphisms increases the risk to develop osteopenia in postmenopausal Tunisian women. Osteopenia seems to be genetically determined. However, osteoporosis is the result of interaction between genetic and environmental factors.

Accuracy of GPS devices for measuring high-intensity running in field-based team sports

We compared the accuracy of 2 GPS systems with different sampling rates for the determination of distances covered at high-speed and metabolic power derived from a combination of running speed and acceleration. 8 participants performed 56 bouts of shuttle intermittent running wearing 2 portable GPS devices (SPI-Pro, GPS-5 Hz and MinimaxX, GPS-10 Hz). The GPS systems were compared with a radar system as a criterion measure. The variables investigated were: total distance (TD), high-speed distance (HSR>4.17 m·s(-1)), very high-speed distance (VHSR>5.56 m·s(-1)), mean power (Pmean), high metabolic power (HMP>20 W·kg(-1)) and very high metabolic power (VHMP>25 W·kg(-1)). GPS-5 Hz had low error for TD (2.8%) and Pmean (4.5%), while the errors for the other variables ranged from moderate to high (7.5-23.2%). GPS-10 Hz demonstrated a low error for TD (1.9%), HSR (4.7%), Pmean (2.4%) and HMP (4.5%), whereas the errors for VHSR (10.5%) and VHMP (6.2%) were moderate. In general, GPS accuracy increased with a higher sampling rate, but decreased with increasing speed of movement. Both systems could be used for calculating TD and Pmean, but they cannot be used interchangeably. Only GPS-10 Hz demonstrated a sufficient level of accuracy for quantifying distance covered at higher speeds or time spent at very high power.

Spatial repolarization heterogeneity and survival in Chagas disease

OBJECTIVES

We investigated if cardiac spatial repolarization heterogeneity might be associated with an increased risk of death in patients with chronic Chagas disease.

METHODS

Repolarization heterogeneity was assessed using the V-index, a recently introduced metric founded on a biophysical model of the ECG. This metric provides an estimate of the standard deviation of the repolarization times across the heart. We analyzed 113 patients (aged 21- 67 years) enrolled between 1998 and 1999 who had a known serological status showing positive reactions to Trypanosoma cruzi. Fourteen subjects died during a 10-year follow-up period.

RESULTS

The V-index was significantly lower in survivor (S) than in non-survivor (NS) subjects (S: 31.2 ± 13.3 ms vs NS: 41.2 ± 18.6 ms, single-tail t-test: p = 0.009, single-tail Wilcoxon rank sum test: p = 0.029). A V-index larger than 36.3 ms was related to a significantly higher risk of death in a univariate Cox proportional-hazards analysis (hazard ratio, HR = 5.34, p = 0.0046). In addition, V-index > 36.3 ms retained its prognostic value in a multivariate Cox proportional-hazards analysis after adjustment for other three clinical variables (left ventricular ejection factor < 0.50, QRS duration > 133 ms, ventricular tachycardia during stress testing or 24 hours Holter) and for T-wave amplitude variability > 30 μV, even using shrinkage, a statistical procedure that protects against over-fitting due to small sample size.

CONCLUSIONS

The study showed that an increased dispersion of repolarization times in patients with Chagas disease, as measured by the V-index, is significantly correlated with the risk of death in a univariate survival analysis. The V-index captures prognostic information not immediately available from the analysis of other established risk factors.

WITHDRAWN: Effect of TCF7L2 polymorphism on the genetic susceptibility to obesity in the Tunisian population

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Effect of ENPP1/PC-1-K121Q and PPARgamma-Pro12Ala polymorphisms on the genetic susceptibility to T2D in the Tunisian population

Diabetes mellitus is the most common chronic metabolic disease. The raising diabetes epidemic is unfolding as an interaction between several environmental factors and a genetic predisposition. The aim of the current study was to evaluate the role of the PPARgamma-Pro12Ala and ENPP1-K121Q polymorphisms on type 2 diabetes (T2D) risk in a case-control study in the Tunisian population. To assess for any association of ENPP1-K121Q and PPARgamma-Pro12Ala polymorphisms with T2D risk, we analysed the genotypic and allelic distributions of each variant in the studied cohort. Our results support that the genetic variation at ENPP1-K121Q predisposes to T2D in the Tunisian population after adjustment on gender, age and BMI status (OR=1.55, 95%CI [1.11-2.16], p=0.007). Conversely, the PPARgamma-Pro12Ala variant seems not to have a significant effect on T2D risk in our Tunisian cohort. However, the minor A-allele would convey protection against overweight in the Tunisian population. In fact, the over weighted subjects showed a significantly lower frequency of A-allele than lean controls (OR=0.49, 95%CI [0.25-0.97], p=0.02). In conclusion, our findings support the hypothesis that ENPP1-121Q is involved in the genetic susceptibility of T2D in the Tunisian population, while the PPARgamma-12Ala allele may confer protection against overweight.

Variation in Top Level Soccer Match Performance

This study examined the influence of the opposing team, seasonal variations and the influence of first half activity on match performance in top-level soccer players. Physical performance measures were collected using the ProZone match analysis system from 20 professional soccer players from the same team and their opponents (n = 188) during a season. Match activities (standing, walking, jogging, running, high-speed running and sprinting), distances (total distance [TD], high-intensity running [HIR] and very high-intensity running [VHIR]) and other measures including involvement with the ball and peak running speed were collected. The influence of opponent team, the level of opposition, first half physical activities on second half activities, and playing position were analysed. The main finding was that TD (r = 0.62, p < 0.05), HIR (r = 0.51, p < 0.05), and VHIR (r = 0.65, p < 0.05) of the reference team was influenced by the activity profile of the opponent teams. The TD and HIR was higher against Best opponent teams compared to Worst opponent teams (p < 0.05), and the TD, HIR and VHIR travelled in the first half significantly influenced the distances covered in the second half. TD, HIR and VHIR were greater at the end of the season. These results may be used to interpret meaningful changes in match performance in top level soccer.

Mutations du gène HFE chez des β-thalassémiques majeurs tunisiens et surcharge en fer

OBJECTIVES

In this study we have determined the allele frequency of HFE mutations H63D and C282Y in a group of Tunisian beta-thalassemia major patients. These two mutations are implicated in hereditary hemochromatosis among Caucasians. In this study we wanted to correlate these mutations with the iron status in major beta-thalassemia patients.

DESIGN AND METHODS

Fifty Tunisian major beta-thalassemia were screening for the C282Y and H63D by digestion of polymerase chain reaction products (RFLP). Serum ferritin level was measured by immunoenzymatic microparticular essay.

RESULTS

The allele frequency of H63D mutation was 17%. C282Y mutation was not present in our studied patients. No statistically significant difference of serum ferritin level was found between major beta-thalassemia with and without HFE mutations.

CONCLUSION

Our results suggest that H63D mutation is so frequent in Tunisian major beta-thalassemia patients than in the general population and that the coinheritance of H63D mutation does not influence the severity of iron overload in these patients.

Validity of simple field tests as indicators of match-related physical performance in top-level professional soccer players

The aim of this study was to examine the construct validity of selected field tests as indicators of match-related physical performance. During the competitive season, eighteen professional soccer players (age 26.2 +/- 4.5 yrs, mass 80.8 +/- 7.8 kg, and height 181.9 +/- 3.7 cm) completed an incremental running field test to exhaustion, a vertical-jump and a repeated-sprint ability (RSA) test. Match physical performance was quantified during official matches using a video-computerized, semi-automatic, match analysis image recognition system, (ProZone, Leeds, UK). The selected measures of match physical performance were: total distance covered (TD), high intensity running (HIR: > 14.4 km . h (-1)), very high intensity running (VHIR:> 19.8 km . h (-1)), sprinting (> 25.2 km . h (-1)) and top running speed. Significant correlations were found between peak speed reached during the incremental field test and TD (r = 0.58, R (2) = 0.34; p < 0.05), HIR (r = 0.65, R (2) = 0.42; p < 0.01) and VHIR (r = 0.64, R (2) = 0.41; p < 0.01). Significant correlations were also found between RSA mean time and VHIR (r = - 0.60, R (2) = 0.36; p < 0.01) and sprinting distance (r = - 0.65, R (2) = 0.42; p < 0.01). Significant differences were found between the best and worst group as defined by the median split technique for peak speed (TD = 12 011 +/- 747 m vs. 10 712 +/- 669, HIR = 3192 +/- 482 m vs. 2314 +/- 347 m, and VHIR = 1014 +/- 120 vs. 779 +/- 122 m, respectively; p < 0.05) and RSA mean time (VHIR = 974 +/- 162 m vs. 819 +/- 144 m, and sprinting = 235 +/- 56 vs. 164 +/- 58 m, respectively; p < 0.05). In conclusion, this study gives empirical support to the construct validity of RSA and incremental running tests as measures of match-related physical performance in top-level professional soccer players.

Prevalence of C282Y and H63D mutations in the haemochromatosis (HFE) gene in Tunisian population

The studies of the HFE mutations: H63D and C282Y in North African populations have revealed the extreme rarity or even the absence of the C282Y mutation. We have examined 1140 chromosomes (570 Tunisian people) for the presence of the two HFE mutations by PCR-RFLP analysis. We have found that the allele frequencies are, respectively, 15.17% (+/-2.1%) for the H63D and 0.09% (+/-0.17%) for the C282Y. These results are consistent with the worldwide spread of the H63D mutation and the north European restriction of the C282Y. This study will be completed by determining whether homozygote trait for H63D and associated risk factors (beta thalassémia) can lead to iron overload in Tunisia.

Allergy to local anaesthetics in dentistry. Myth or reality?

BACKGROUND

Local anesthetics (LA) are frequently used in dentistry. Although these drugs are usually well-tolerated, they can sometimes provoke adverse reactions of various types and severity. The true incidence of LA allergic reactions is unknown. The objectives of this study were (i) to evaluate the incidence of immediate adverse events in subjects requiring local anesthetic injection in order to receive dental treatment; (ii) to assess the incidence of anaphylactic allergic reactions among those recorded as adverse events and (iii) to analyze the relationship between the atopic antecedents of these patients and documented allergic reactions.

MATERIALS AND METHODS

A prospective, open-label, non-comparative study including 5,018 subjects who received LA during dental treatment, despite their age, was carried out in 7 private or public odontological centers. All the possible reactions that could appear during the first hour of anesthetic administration were assessed.

RESULTS

Twenty-five adverse reactions were diagnosed, representing 0.5 % of the study population. None of these reactions was due to an allergic cause. Most (22/25) were mild, quickly reversible psychogenic or vasovagal reactions. One case was related to defects in the anesthetic technique. In two further cases, allergic etiology was ruled out after skin and dose provocative challenge tests with the anesthetic. In conclusion, allergic reactions to LA are very rare. Most adverse reactions are psychogenic or vasovagal. Physicians and dentists should be aware of these facts in order to minimize the frequent fears and myths concerning the use of LA in the dentist's office.

MRI study of thalamic volumes in bipolar and unipolar patients and healthy individuals

The thalamus is a key structure in brain anatomic circuits potentially involved in the pathophysiology of mood disorders. Available findings from studies that examined this brain region in mood disorder patients have been conflicting. To examine the hypothesis of anatomical abnormalities in the thalamus in patients with mood disorders, we conducted a magnetic resonance imaging (MRI) study in 25 bipolar patients (mean age+/-S.D.=34.4+/-9.8 years), 17 unipolar patients (mean age+/-S.D.=42.8+/-9.2 years), and 39 healthy control subjects (mean age+/-S.D.=36.6+/-9.7 years). Thalamic volumes Gray Matter were measured blindly with a semi-automated technique. Multivariate analysis of variance, with age and gender as covariates, revealed no significant differences in left or right thalamic volumes among bipolar patients, unipolar patients and healthy individuals. There were no significant effects of gender, age at illness onset, episode type, number of episodes, length of illness, or family history of mood disorders on thalamic measurements. Although functional abnormalities in the thalamus are likely to be implicated in the pathophysiology of mood disorders, no abnormalities in thalamic size appear present in bipolar or unipolar individuals.

A method for the evaluation of the change in volume of retrieved acetabular cups

Studies on retrieved hip prostheses are currently performed in order to assess the wear mechanisms and the overall wear rate of such artificial joints. Several reported studies on the survival of artificial hips have been based on the measurement of the amount of worn material directly on retrieved acetabular cups. The estimation of the change in volume, V, of the cup cavity is particularly difficult in the case of slight wear due to several factors of which the most critical is the lack of information on the unworn geometry of the cup. This paper presents a new measuring technique, which is described in detail and has been applied to estimate the wear of 65 acetabular cups harvested from revised hip arthroplasty. The coordinate data of several points on the articular surface are sampled using a coordinate measuring machine (CMM). The value of V is calculated mathematically from the measurements by using the hypothesis that the actual shape of both slightly worn and highly worn surfaces has a small departure from a truly spherical shape. The wear volume is estimated with reasonable accuracy mainly on those cups showing penetration depths greater than 0.2 mm, corresponding to an amount of wear greater than 100 mm3 for a 32 mm cup. The uncertainty in the results is estimated for each cup. The repeatability of the technique is studied for a case showing very slight wear. The advantages, disadvantages and limitations of the method are presented and discussed.

Image analysis to improve diagnosis of exfoliation

PURPOSE

To improve visualization of exfoliation material in standard colour photographs by image analysis.

METHODS

Standard anterior segment colour photographs taken from 17 patients with known exfoliation were subjected to film scanning with a maximum accuracy of 3175 dpi.

RESULTS

Before image scanning, visualization of exfoliation was classified as barely visible in 10 (59%) patients and clearly visible in 7 (41%) patients. After the image scanning, exfoliation material became clearly visible in 13 (76%) patients and could easily be demonstrated.

CONCLUSION

Diagnosis of exfoliation material can be improved by standard film scanning.