Spliceosome malfunction causes neurodevelopmental disorders with overlapping features

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.

Recurrent pneumothorax after cesarean delivery in the critically ill pregnant with severe COVID-19 ARDS: a case report

OBJECTIVE

Few data are available on the ICU management and on the possible respiratory complications of invasively ventilated pregnant patients affected by COVID-19 pneumonia, especially in the early phase of pregnancy. Tension pneumothorax has been previously described as a rare cause of respiratory failure after delivery, but its occurrence in the postpartum of COVID-19 patient has not been reported yet. We hereby describe the ICU management of a 23rd gestational week pregnant woman who underwent invasive mechanical ventilation, prone positioning, and cesarean delivery during her ICU stay for COVID-19 related pneumonia. Moreover, we focused on the occurrence and management of recurrent tension pneumothorax after the cesarean delivery.

CASE REPORT

A 23rd gestational week pregnant woman was admitted to the ICU for a COVID-19 bilateral pneumonia and underwent invasive mechanical ventilation and prone positioning. Cesarean delivery was planned during the ICU stay, while the patient was receiving invasive mechanical ventilation. After delivery, the patient experienced a recurrent pneumothorax that required the positioning of multiple chest drains.

CONCLUSIONS

In pregnant critically ill COVID-19 patients, mechanical ventilation management is particularly challenging, especially in the postpartum period. Prone positioning is feasible and can improve oxygenation and respiratory system compliance, while tension pneumothorax must be suspected if the respiratory function suddenly deteriorates after delivery.

Role of the cytopathologist during the procedure of fine-needle aspiration biopsy of thyroid nodules

Purpose

This study aimed to conduct a diagnostic and cost-effective analysis of the cytopathology assistance in the ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) for characterising thyroid nodules.

Materials and methods

We reviewed the reports relative to 9061 US-guided FNABs for the histologic definition of the nature of thyroid nodules: 45.4% completed with the cytopathologist assistance and 54.6% by the radiologist alone.

We also performed the cost-effectiveness analysis (CEA) of the procedure with and without the cytopathologist assistance.

Results

We found a significant positive correlation between the adoption/non-adoption of cytopathologist assistance and the number of indeterminate (TIR1) (Chi-square; z-score, Z = 10.22; critical value 5%, C = 1.96; p < 0.001). The cytopathologist's absence was correlated with the number of TIR 1 (Pearson correlation, product–moment correlation r = 0.059; critical value 5%, C = 0.008; p < 0.001).

The total cost of the model's cytopathologist-assistance branch is 109.87€, while the total cost of the non-cytopathologist-assistance branch is 95.08€.

Conclusion

The cytopathologist assistance resulted in fewer nondiagnostic results, thus excluding the procedure's repetition but involved a higher expense, mainly due to the professional cost of the pathologist's participation. These data may provide decision-makers in healthcare with a practical evidence based on the opportunity to include the cytopathologist assistance in the thyroid nodule's FNAB depending on the available resources and the population's expectance.

Supplementary information

The online version contains supplementary material available at 10.1186/s13244-021-01053-y.

A tool to predict survival in stage IV entero-pancreatic NEN

PURPOSE

Well-differentiated stage IV neuroendocrine neoplasms (NEN) have an extremely heterogeneous, unpredictable clinical behavior. Survival prognostic markers, such as the recently proposed NEP-Score, would be very useful for better defining therapeutic strategies. We aim to verify NEP-Score applicability in an independent cohort of stage IV well-differentiated (WD) gastroentero-pancreatic (GEP) NEN, and identify a derivate prognostic marker taking into account clinical and pathological characteristics at diagnosis.

METHODS

Age, site of primary tumor, primary tumor surgery, symptoms, Ki67, timing of metastases of 27 patients (10 females; mean age at diagnosis 60.2 ± 2.9 years) with stage IV WD GEP NEN were evaluated to calculate the NEP-Score at the end of follow-up (NEP-T). We calculated the NEP-Score at diagnosis (NEP-D), which does not consider the appearance of new metastases during follow-up. Patients were subdivided according to whether they were alive or not at the end of follow-up (EOF) and an NEP-Score threshold was investigated to predict survival.

RESULTS

Mean NEP-T and mean NEP-D were significantly lower in 15 live patients as compared to 12 deceased patients (p < 0.01) at EOF. We identified an NEP-D = 116 as the cutoff that significantly predicts survival. No gender differences were identified.

CONCLUSIONS

In our series, we confirmed NEP-Score applicability. In addition, we propose NEP-D as a simple, quick and cheap prognostic score that can help clinicians in decision making. NEP-D threshold can predict NEN aggressiveness and may be used to define the best personalized therapeutic strategy.

POS1406 DEVELOPMENT OF A DIAGNOSTIC ALGORITHM FOR THE DIFFERENTIAL DIAGNOSIS OF INTERSTITIAL LUNG DISEASE: PRELIMINARY DATA FROM A MULTICENTER RETROSPECTIVE CASE-CONTROL STUDY

Background:

Interstitial lung diseases (ILDs) represent a heterogeneous group of disorders with different treatment and prognosis. ILD may be the presenting or the dominant manifestation of a connective tissue disease (CTD). Multidisciplinary team (MDT) discussion is currently the diagnostic standard. However, there is no consensus on how MDT diagnosis is validated and on the core elements of discussion.

Objectives:

To explore the performance of a diagnostic algorithm for the differential diagnosis of ILD based on clinical, serological and radiological data, supporting clinician decision-making.

Methods:

In this retrospective study, analysis was performed on clinical, serological and radiological features at diagnosis and 1-year follow-up in 71 patients, including 41 with CTD-ILD and 30 with idiopathic interstitial pneumonias (IIPs). In order to identify robust hallmarks, we conducted the Receiver Operating Characteristic (ROC) curve analyses in logistic regression, to discriminate significantly different features between CTD-ILD and non-CTD-ILD groups.

Results:

Out of 71 patients 46% were women, with a mean age of 66±11 years. History of smoking (8.8% current and 39.8% former smokers), was more associated with IIPs. 54% of patients had dyspnea on exertion and 39% dry cough, both more frequently associated with IIPs (p = 0.016). Among radiological features, NSIP pattern was more frequent in CTD-ILD, while UIP was associated with IIP. Lung fibrosis extent was greater in IIP (p = 0.063), in which CT is generally performed in symptomatic patients at diagnosis and rarely for screening purpose. Baseline features with good performance (OR p-value ≤ 0.05) were eligible as potential candidate discriminators: age, sex, smoking habit, rheumatological signs and symptoms, autoantibodies, ILD patterns were selected, to build a multivariate model with high discrimination accuracy (AUC 0.971). The model has a sensitivity of 100% and specificity of 89.7%. The most relevant correlations between population features and CTD-ILD are presented in Table 1.

Table 1.

Correlation analysis of the most significant discriminative features.

FeaturesOdds ratioP valueArea under ROC curveSex (female)3.290.019*0.643Age0.910.001*0.736Smoke0.12<0.001*0.738Respiratory symptoms (dyspnea and/or dry cough)0.260.016*0.644Rheumatological symptoms (any)28.8<0.001*0.839 • Raynaud’s phenomenon15.040.0110.654 • Cutaneous manifestations8.160.0530.593Autoantibodies (ANA, ENA, RF, ACPA, myositis-specific antibodies or aPL) positivity33.68<0.001*0.792Lung function test • Forced vital capacity (%FVC)0.970.1750.638 • Diffusing capacity of carbon monoxide (%DLCO)0.960.0720.665High-resolution computed tomography (HRCT) imaging • Honeycombing0.340.0680.593 • Emphysema0.140.005*0.647 • Extent of lung involvement (%)0.970.0630.668HRCT pattern • NSIP vs UIP30.033*0.625

Abbreviations: ANA, antinuclear antibody; ENA, extractable nuclear antigen; RF, rheumatoid factor; ACPA, anti-citrullinated peptide antibody; aPL, antiphospholipid antibody; NSIP, nonspecific interstitial pneumonia; UIP, usual interstitial pneumonia.

Conclusion:

Our study shows that the most important variables in the differential diagnosis between CTD-ILD versus IIPs include, as expected, autoimmune features (rheumatological symptoms and serological data). Questionnaire tool containing these specific hallmarks may be relevant during MDT discussion, limiting the number of misdiagnosed CTD-ILDs and potentially avoiding further unnecessary investigations. However, only prospective cohort studies of early onset ILD are needed to fully validate the relative importance of clinical, serological, functional and radiological data.

References:

[1]Furini F. et al, The Role of the Multidisciplinary Evaluation of Interstitial Lung Diseases: Systematic Literature Review of the Current Evidence and Future Perspectives. Front Med (Lausanne). 2019; 6: 246.

Disclosure of Interests:

None declared

Absence of iron-responsive element-binding protein 2 causes a novel neurodegenerative syndrome

Disruption of cellular iron homeostasis can contribute to neurodegeneration. In mammals, two iron-regulatory proteins (IRPs) shape the expression of the iron metabolism proteome. Targeted deletion of Ireb2 in a mouse model causes profoundly disordered iron metabolism, leading to functional iron deficiency, anemia, erythropoietic protoporphyria, and a neurodegenerative movement disorder. Using exome sequencing, we identified the first human with bi-allelic loss-of-function variants in the gene IREB2 leading to an absence of IRP2. This 16-year-old male had neurological and haematological features that emulate those of Ireb2 knockout mice, including neurodegeneration and a treatment-resistant choreoathetoid movement disorder. Cellular phenotyping at the RNA and protein level was performed using patient and control lymphoblastoid cell lines, and established experimental assays. Our studies revealed functional iron deficiency, altered post-transcriptional regulation of iron metabolism genes, and mitochondrial dysfunction, as observed in the mouse model. The patient's cellular abnormalities were reversed by lentiviral-mediated restoration of IRP2 expression. These results confirm that IRP2 is essential for regulation of iron metabolism in humans, and reveal a previously unrecognized subclass of neurodegenerative disease. Greater understanding of how the IRPs mediate cellular iron distribution may ultimately provide new insights into common and rare neurodegenerative processes, and could result in novel therapies.

MSTO1 mutations cause mtDNA depletion, manifesting as muscular dystrophy with cerebellar involvement

MSTO1 encodes a cytosolic mitochondrial fusion protein, misato homolog 1 or MSTO1. While the full genotype–phenotype spectrum remains to be explored, pathogenic variants in MSTO1 have recently been reported in a small number of patients presenting with a phenotype of cerebellar ataxia, congenital muscle involvement with histologic findings ranging from myopathic to dystrophic and pigmentary retinopathy. The proposed underlying pathogenic mechanism of MSTO1-related disease is suggestive of impaired mitochondrial fusion secondary to a loss of function of MSTO1. Disorders of mitochondrial fusion and fission have been shown to also lead to mitochondrial DNA (mtDNA) depletion, linking them to the mtDNA depletion syndromes, a clinically and genetically diverse class of mitochondrial diseases characterized by a reduction of cellular mtDNA content. However, the consequences of pathogenic variants in MSTO1 on mtDNA maintenance remain poorly understood. We present extensive phenotypic and genetic data from 12 independent families, including 15 new patients harbouring a broad array of bi-allelic MSTO1 pathogenic variants, and we provide functional characterization from seven MSTO1-related disease patient fibroblasts. Bi-allelic loss-of-function variants in MSTO1 manifest clinically with a remarkably consistent phenotype of childhood-onset muscular dystrophy, corticospinal tract dysfunction and early-onset non-progressive cerebellar atrophy. MSTO1 protein was not detectable in the cultured fibroblasts of all seven patients evaluated, suggesting that pathogenic variants result in a loss of protein expression and/or affect protein stability. Consistent with impaired mitochondrial fusion, mitochondrial networks in fibroblasts were found to be fragmented. Furthermore, all fibroblasts were found to have depletion of mtDNA ranging from 30 to 70% along with alterations to mtDNA nucleoids. Our data corroborate the role of MSTO1 as a mitochondrial fusion protein and highlight a previously unrecognized link to mtDNA regulation. As impaired mitochondrial fusion is a recognized cause of mtDNA depletion syndromes, this novel link to mtDNA depletion in patient fibroblasts suggests that MSTO1-deficiency should also be considered a mtDNA depletion syndrome. Thus, we provide mechanistic insight into the disease pathogenesis associated with MSTO1 mutations and further define the clinical spectrum and the natural history of MSTO1-related disease.

Fetal exposure to polybrominated diphenyl ethers and the risk of hypospadias: focus on the congeners involved

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and their endocrine-disrupting properties have focused growing attention regarding their teratogenic potential. We have recently documented that mothers of children born with hypospadias had been exposed to statistically higher levels of PBDE during pregnancy than mothers of healthy controls. However, it is not known which congeners of PBDE are associated with this putative teratogenic effect.

OBJECTIVES

To identify PBDE congeners associated with increased risk for hypospadias.

STUDY METHODS

Hair samples from mothers were analyzed and compared between hypospadias cases and healthy controls for eight PBDE congeners using gas chromatography mass spectrometry (GC/MS). Polybrominated diphenyl ether levels were measured in the 0- to 3-cm segment closest to the skull of maternal hair as a proxy for in utero exposure of mothers who lived in the same environment for the duration of their pregnancy.

RESULTS

Median maternal hair levels of five PBDE congeners (28, 47, 99, 153, and 154) and of total PBDE (∑PBDE) were significantly higher among mothers of infants with hypospadias (n = 152) than among controls (n = 64). Apparent greater differences in the lower brominated congeners, especially in BDE-47 and BDE-99, may be due to the fact that they had been used in larger amounts, and their persistence properties confer longer exposure.

CONCLUSIONS

The majority of the lower brominated PBDE congeners measured in maternal hair exhibited higher PBDE body burden during pregnancy in mothers of infants who were born with hypospadias.

Triple A syndrome presenting as complicated hereditary spastic paraplegia

BACKGROUND

Hereditary spastic paraplegia (HSP) is a group of rare disorders characterized by spastic paraparesis and other symptoms. Often, other diseases can mimic HSP, which may delay diagnosis and treatment.

METHODS

Whole exome sequencing was performed in families with clinically suspected HSP without a genetic diagnosis.

RESULTS

We report three patients from two families who presented with lower limb spasticity, muscular atrophy, and other neurological symptoms, who were clinically diagnosed with complicated HSP. Whole exome sequencing revealed bi-allelic AAAS nonsense mutations; one individual was homozygous for the p.(Arg478*) mutation, and two siblings were homozygous for the p.(Arg286*) mutation, leading to the diagnosis of triple A syndrome. This rare syndrome is typically characterized by a triad of symptoms: achalasia, adrenal insufficiency, and alacrima, and is often accompanied by other neurological abnormalities.

CONCLUSIONS

Our findings suggest that triple A syndrome should be suspected in complicated HSP patients without a known genetic cause, especially if at least one of the main triad of triple A syndrome symptoms is present.

Association of In Utero Exposure to Polybrominated Diphenyl Ethers With the Risk of Hypospadias

IMPORTANCE

Polybrominated diphenyl ethers (PBDEs) are added to many consumer products as flame retardants, and their endocrine-disrupting properties are a growing health concern in pregnancy.

OBJECTIVE

To investigate whether in utero PBDE exposure as measured in maternal hair is associated with increased risk for hypospadias.

DESIGN, SETTING, AND PARTICIPANTS

In this case-control study, the setting was the urology clinic of a tertiary pediatric hospital between January 3, 2011, and April 1, 2013. Participants were children diagnosed as having hypospadias and their mothers and a control group of children without hypospadias and their mothers. Dates of data analysis were September 3, 2017, to December 28, 2017.

EXPOSURES

Gestational exposure to 8 PBDEs as measured in the 3-cm segment closest to the skull of maternal hair by gas chromatography-mass spectroscopy as a proxy for in utero exposure. The mothers resided in the same household for the duration of their pregnancy.

MAIN OUTCOMES AND MEASURES

Difference in total maternal hair PBDE levels between the hypospadias and control groups.

RESULTS

Total PBDE levels were significantly higher among mothers of infants with hypospadias (n = 152) (total PBDE level, 51.4 pg/mg; interquartile range, 35.8-78.5 pg/mg) than among controls (n = 64) (total PBDE level, 35.8 pg/mg; interquartile range, 18.1-69.9 pg/mg) (P = .02). Of the 152 women with sufficient hair samples for analysis in the case group, 89 completed a questionnaire and were included in a multivariable analysis, and of the 64 women with sufficient hair samples for analysis in the control group, 54 completed a questionnaire and were included in a multivariable analysis. Adjusting for potential confounders, hypospadias was associated with a relative 48.2% (95% CI, 23.2%-65.4%) higher maternal level of total PBDE levels in the multivariable analysis.

CONCLUSIONS AND RELEVANCE

In this analysis, mothers of children with hypospadias were exposed during pregnancy to significantly higher levels of PBDEs. The results of this study suggest that level of exposure to PBDEs during gestation may have a role in the etiology of hypospadias.

Impact of Mobility Device Use on Quality of Life in Children With Friedreich Ataxia

OBJECTIVE

To determine how mobility device use impacts quality of life in children with Friedreich ataxia.

STUDY DESIGN

Data from 111 pediatric patients with genetically confirmed Friedreich ataxia were collected from a prospective natural history study utilizing standardized clinical evaluations, including health-related quality of life using the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Module.

RESULTS

Mobility device use was associated with worse mean PedsQL total, physical, emotional, social, and academic subscores, after adjusting for gender, age of disease onset, and Friedreich Ataxia Rating Scale score. The magnitude of the difference was greatest for the physical subscore (-19.5 points, 95% CI = -30.00, -8.99, P < .001) and least for the emotional subscore (-10.61 points, 95% CI = -20.21, -1.02, P = .03). Transition to or between mobility devices trended toward worse physical subscore (-16.20 points, 95% CI = -32.07, -0.33, P = .05).

CONCLUSIONS

Mobility device use is associated with significant worsening of all domains of quality of life in children with Friedreich ataxia.

Erratum: "A Case-Control Study of Maternal Polybrominated Diphenyl Ether (PBDE) Exposure and Cryptorchidism in Canadian Populations"

[This corrects the article DOI: 10.1289/EHP522.].

A Case-Control Study of Maternal Polybrominated Diphenyl Ether (PBDE) Exposure and Cryptorchidism in Canadian Populations

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are flame retardants found in North American household products during the past four decades. These chemicals leach out in dust as products age, exposing individuals daily through inhalation and ingestion. Animal studies suggest that PBDEs disrupt sex hormones and adversely affect development of the reproductive system.

OBJECTIVES

In the present study, we examined whether there is a link between maternal hair PBDE concentrations and the risk of cryptorchidism (undescended testes) in male infants; testis descent is known to be dependent on androgens.

METHODS

Full-term male infants were recruited through clinics in Montreal, Toronto, and London, Canada. Boys with cryptorchidism at 3-18 months of age (n=137) were identified by pediatric urologists and surgeons; similar-aged controls (n=158) had no genitourinary abnormalities as assessed by pediatricians. Eight BDE congeners (BDE-28, -47, -99, -100, -153, -154, -183, -209) were measured by GC-MS (gas chromatography-mass spectrometry) in maternal hair samples collected at the time of recruitment.

RESULTS

The ∑PBDE geometric mean for maternal hair was 45.35 pg/mg for controls and 50.27 pg/mg for cases; the concentrations of three BDEs (BDE-99, -100, and -154) were significantly higher in cases than controls in unadjusted models. In adjusted models, every 10-fold increase in the concentration of maternal hair BDE-99 [OR=2.53 (95% CI: 1.29, 4.95) or BDE-100 [OR=2.45 (95% CI: 1.31, 4.56)] was associated with more than a doubling in the risk of cryptorchidism. BDE-154 [OR=1.88 (95% CI: 1.08, 3.28) was also significant.

CONCLUSIONS

Our results suggest that maternal exposure to BDE-99, -100, and -154 may be associated with abnormal migration of testes in the male fetus. This may be due to the anti-androgenic properties of the PBDEs. https://doi.org/10.1289/EHP522.

Hair as a biomarker of systemic exposure to polybrominated diphenyl ethers

The efficacy of using hair as a biomarker for exposure to polybrominated diphenyl ether (PBDE) flame retardants was assessed in humans and an animal model. Paired human hair and serum samples were obtained from adult men and women (n = 50). In parallel, hair, serum, liver, and fat were collected from adult male Sprague-Dawley rats exposed to increasing doses of the PBDE mixture found in house dust for 70 days via the diet. All samples were analyzed by GC-MS for eight common PBDEs: BDE-28, -47, -99, -100, -153, -154, -183, and -209. Paired human hair and serum samples had five congeners (BDE-28, -47, -99, -100, and -154) with significant individual correlations (0.345-0.566). In rat samples, BDE-28 and BDE-183 were frequently below the level of detection. Significant correlations were observed for BDE-47, -99, -100, -153, -154, and -209 in rat hair, serum, liver, and fat across doses, with r values ranging from 0.803 to 0.988; weaker correlations were observed between hair and other tissues when data from the lowest dose group or for BDE-209 were analyzed. Thus, human and rat hair PBDE measurements correlate strongly with those in alternative matrices, validating the use of hair as a noninvasive biomarker of long-term PBDE exposure.

Legal aspects in implantable defibrillator extraction

At the Institute of Legal Medicine in Chieti, a case of iatrogenic superior vena cava perforation was observed during laser extraction of an infected biventricular implantable cardiac defibrillator. The presentation of this particular case represented a starting point for studying the occurrence of similar complications in literature, since their knowledge and understanding should induce resolution of any organisation problems, aid in increasing physicians' training and impose the availability of cardiac surgeons during such operations.

Persistent genomic instability in peripheral blood lymphocytes from Hodgkin lymphoma survivors

Advances in cancer treatment have led to an increase in patient survival. However, exposure to genotoxic chemotherapeutic agents and ionizing radiation may induce persistent genetic damage in cancer survivors. In this study, we detected genomic instability in chromosomes of peripheral blood lymphocytes from Hodgkin lymphoma patients, 2-17 years after MOPP (nitrogen mustard, Oncovin, procarbazine, and prednisone) chemotherapy with or without radiotherapy. Samples were obtained from 11 healthy individuals, 5 pretreatment patients, and 20 posttreatment patients. Cytogenetic analysis with GTG banding was performed on 1,000 lymphocyte metaphases per donor to identify genomic instability, including numerical and structural chromosomal aberrations, at a resolution of 10 Mb across the entire genome. Our results showed that anticancer treatment did not induce significant differences in the frequency of aneuploidy among the three study groups. However, 1 of the 11 healthy individuals, and 13 of the 20 posttreatment patients had a high frequency of chromosomal breaks and gross chromosomal rearrangements. The types of aberrations observed were random and complex, consistent with persistent genomic instability that was induced by cancer treatment. Clonal expansion of cells with chromosomal lesions was observed in one posttreatment patient only. These findings show that anticancer treatments induce persistent genomic instability, but not aneuploidy. Chemotherapy may affect genes with a role in DNA damage surveillance or repair, which in turn allows the accumulation of nontargeted structural chromosomal damage in future generations of cells. This genomic instability may facilitate the development of second malignancies in Hodgkin lymphoma survivors.

Detection of polybrominated biphenyl ethers (PBDEs) in pediatric hair as a tool for determining in utero exposure

INTRODUCTION

Cryptorchidism, or undescended/maldescended testis, is the most common birth defect of male genitalia. Its prevalence has been increasing over the past few decades. This may be due to an increase in the prevalence of anti-androgenic chemicals such as polychlorinated biphenyls, organochloride pesticides, plasticizers and fungicides. A newer group of chemicals, brominated flame retardants (BFRs), are being implicated as endocrine-disrupting chemicals. These chemicals are used worldwide in polymers that are incorporated into a variety of consumer products (e.g., textile, computers and televisions, insulating foam, electrical equipment and kitchen appliances). In order to quantify BFRs we introduce the use of hair levels of polybrominated diphenyl esters (PBDEs) as biomarkers of systemic exposure. This approach will allow for the estimation of in utero BFR exposure, in the process of evaluating the potential link between the incidence of cryptorchidism in newborn males and level of exposure of the pregnant mother to environmentally relevant BFRs. For that end we have developed a GC/MS assay in which children's hair is analyzed for the presence of polybrominated biphenyl ethers (PBDEs).

METHODS

In this pilot, 10-40mg of hair from 24 children (12 newborn and 12 from children 1 to 15 years) was extracted overnight at 40°C with 4N HCl and hexane (4:1). The samples were eluted from 2g NaSO(4):2g Florisil SPE columns with 8mL hexane. Dried samples are reconstituted with anhydrous isooctane and injected onto a GC/MS and analyzed for BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183 and BDE-209.

RESULTS

PBDEs were detected in all of the newborn and child hair. The ΣPBDE ranged from 0.038 to 1.01pg/mg newborn hair and from 0.208 to 2.695ng/mg child hair. The most abundant PBDE in newborn hair was BDE-153 while in child hair the variable PBDEs were BDE-47 and BDE-99. The highest molecular weight congener BDE-209 was detected in 10/24 pediatric hair samples. The LOQ is 0.0625pg/mg (BDE-209 0.625pg/mg) and the efficiency of extraction was between 70 and 90%.

CONCLUSION

This GC/MS method is sufficiently sensitive to detect the presence of all 8 PBDE congeners tested in as little as 10mg of pediatric hair. The results show that PBDEs are present in newborn hair, making this matrix useful in examining in utero exposure to PBDEs and linking it to cryptorchidism.

First report of an acute purulent maxillary sinusitis caused by Pseudomonas aeruginosa secondary to dental implant placement in an immunocompetent patient

STUDY DESIGN

In this case report, we present maxillary Pseudomonas aeruginosa sinusitis in an immunocompetent patient who underwent an autologous bone transplant for the insertion of dental implants.

RESULTS

The infection was eradicated after removal of the dental implants and long-term antibiotic therapy.

CONCLUSION

Despite the infection resolution, severe complications were observed with important legal consequences.

Diagnostic failure of ciprofloxacin-induced spontaneous bilateral Achilles tendon rupture: case-report and medical-legal considerations

Rare side-effects of fluoroquinolone therapy are tendinitis and tendon rupture. Many reports have demonstrated that the concomitant use of corticosteroids, in patients aged 60 years or older, increase the risk substantially. We present a case of spontaneous bilateral Achilles tendon rupture induced by ciprofloxacin and methylprednisolone. A 61-year-old woman was diagnosed with Bronchiolitis Obliterans with Organizing Pneumonia (BOOP) and was started on oral ciprofloxacin 500 mg twice daily for 3 weeks and on oral methylprednisolone 16 mg twice daily for 2 weeks. The diagnosis was made after doctors, rather than stop drug therapy and advise complete rest, had mistakenly prescribed for the woman to undergo physiotherapy and local NSAIDs, thus favoring the onset of tendon ruptures and resulting in surgical and legal implications. Inspired by this case, we also submit a brief review on professional liability in Orthopaedics.

The neural cell adhesion molecule (NCAM) present in the cerebrospinal fluid of multiple sclerosis patients is unsialylated

The neural cell adhesion molecule (NCAM) is a glycoprotein localised in the plasma membrane of neural and glial cells, which plays a role in myelination and remyelination. It increases in the cerebrospinal fluid (CSF) of acute multiple sclerosis (MS) patients treated with corticosteroids who are improving after an attack, but it has not been shown if it appears in its sialylated (PSA) or unsialylated form. We studied the NCAM and the PSA-NCAM in serum and CSF samples of 16 acute and non-acute MS patients and in the sera of 10 non-neurological controls. The NCAM and the PSA-NCAM were dosed by two different ELISA previously set-up. The NCAM in the serum and in the CSF of the control group presented mean levels similar to those shown in previous papers: 1620 +/- 216 and 970 +/- 210 ng/ml. In the MS patient group the means were 1700 +/- 546 in the sera and 926 +/- 285 in the CSFs. All the sera were PSA-NCAM-positive: the mean PSA-NCAM concentration in the control group was 3150 +/- 950 ng/ml, while in the MS patient group it was 3570 +/- 905 ng/ml. The correlation between serum levels of NCAM and PSA-NCAM was highly significant (p < 0.001). Student's "t" test did not show any significant difference between serum levels of the two groups, both for the NCAM and for the PSA-NCAM. CSF samples did not show any positive results for the PSA-NCAM, in either controls or in MS patients. These results demonstrate that the high levels of NCAM we previously found in the CSF of improving MS patients treated with steroids did not contain a quota of PSA-NCAM, but only the unsialylated soluble form of the molecule.

A case of accidental aspiration of a dental cutter into the bronchopulmonary tree: clinical implications and legal considerations

Though rare, aspiration of foreign bodies into the lower airway during dental procedures may have sequelae that endanger the patient's health. This article discusses the risks associated with routine dental procedures, patient safety precautions during endodontal therapy, and the medicolegal aspects of professional liability in dentistry. The case concerns a 31-year-old man who inhaled a dental cutter which impacted in the left posterior basal lobe. Bronchoscopy failed to retrieve the object; a magnetic resonance imaging study was performed and the object was removed by video-assisted thoracic surgery. Procedure-related criticalities, precautionary measures for patient safety, and medicolegal implications of professional negligence were identified from dentistry protocols and a review of the literature. Professional liability hinges on scrupulous exercise of care and adoption of safety precautions even in routine ''low risk'' dental procedures.

BCR-ABL, ETV6-RUNX1 and E2A-PBX1: prevalence of the most common acute lymphoblastic leukemia fusion genes in Mexican patients

This study was conducted to determine the frequency of the most common fusion genes in Mexican pediatric patients with acute lymphoblastic leukemia (ALL). Molecular analysis using RT-PCR was carried out in 53-blood samples: 52 patients with de novo ALL and one with relapsed ALL. The ETV6-RUNX1 fusion was found in 7 cases (13.5%), BCR-ABL fusion was detected in 2 cases (3.8%), and 6 patients (11.5%) expressed the chimeric gene E2A-PBX1. The prevalence of E2A-PBX1 is one of the highest that has been described thus far in childhood ALL. Furthermore, we detected both the BCR-ABL, and E2A-PBX1 fusion in the relapsed patient. With regards to the immunophenotype, ETV6-RUNX1 was expressed in both pre-B and T-cell cases, while the presence of E2A-PBX1 and BCR-ABL was associated with the pre-B ALL phenotype. The prevalence of E2A-PBX1 in Mexican pediatric cases supports the existence of ethnic differences in the frequency of molecular markers of ALL.

Trisomy of the short arm of chromosome 5 due to a de novo inversion and duplication (5)(p15.3 p13.3)

Partial trisomies of the short arm of chromosome 5 are uncommon. The first description was made by Lejeune et al., in 1964. It has been suggested that the critical region for 5p trisomy syndrome lies between 5p10 and 5p13. We report on a Mexican girl who developed severe mental retardation and generalized tonic clonic seizures at age 1 year. On physical examination at age 5 years, she had macrodolichocephaly, upslanted palpebral fissures, bilateral inner epicanthic folds, low nasal root, and malformed ears with posterior rotation which are clinical characteristics of 5p trisomy syndrome. The cytogenetic study with G bands and FISH with painting for chromosome 5 and with the cri-du-chat 5p15 unique sequence probe showed a duplication and inversion of 5p [46,XX, dup(5)(p15.3 p13.3)] which overlaps with the critical region for 5p trisomy syndrome. Our patient shares clinical characteristics with the patients described in the literature with involvement of this critical region. Both parents have normal karyotypes indicating the rearrangement is de novo. Only one patient has been reported in the literature with the same cytogenetic rearrangement as our patient, but this patient had a different phenotype. Since they only performed conventional cytogenetics and we performed FISH to confirm the diagnosis, the differences in the phenotypes could be explained by the presence of other genes involved in the rearrangement. The combined use of conventional and molecular cytogenetics in this case allows a more precise diagnosis and furthers knowledge in phenotype/genotype correlation.

Antithyroid antibodies in the CSF: their role in the pathogenesis of Hashimoto's encephalopathy

Antithyroid antibodies and circulating immune complexes (CIC) were found in the CSF of six patients with Hashimoto's encephalopathy (HE) but not in the CSF of 21 controls. The synthesis of autoantibodies and CIC was intrathecal and their titers were independent of the patients' clinical status or therapy. Their presence in the CSF of patients with acute or subacute encephalopathy may be useful in diagnosing HE.

XV-2c/KM-19 haplotype analysis of cystic fibrosis mutations in Mexican patients

We analyzed 97 unrelated Mexican cystic fibrosis (CF) patients and their first-degree relatives to study the association of XV2C/TaqI/KM19/PstI haplotypes with CF mutations in this population. Haplotype phases could be established in 148 CF and 110 normal chromosomes, and haplotype distributions of normal and CF chromosomes differed significantly (P < 0.001). DeltaF508 and G542X mutations accounted for 56% of CF chromosomes and were found to be associated with haplotype B in 97.2% and 72.7% of chromosomes, respectively. The haplotype distribution of CF chromosomes carrying other rare and unknown mutations was similar to that of normal chromosomes (P > 0.05), haplotypes A and C being the most frequent. This is in accordance with the extensive heterogeneity and the spectrum of mutations reported in Mexican CF patients. We also report the haplotype distribution of all informative chromosomes bearing rare mutations; some were found to be associated with previously reported haplotypes, whereas others were found on different haplotypes. Recombination or recurrence of mutations may explain these different associations, although other intragenic markers must be used to better understand the origin and dispersion of CF mutations in our country. XK haplotype analysis allowed carrier detection among sibs in 24.3% of families, showing that this method may be useful for carrier detection in populations with high allelic heterogeneity.

Carrier detection and prenatal molecular diagnosis in a Duchenne muscular dystrophy family without any affected relative available

In this paper we report a family where the affected DMD patients were not available for study and a molecular strategy was used for female carriers detection and for prenatal diagnosis. Linkage analysis was performed with two markers within the DMD gene, in all family members screened. DMD markers used (pERT87.8/Taq1 and pERT87.15/Xmn1) seemed not to be informative because the propositas mother (II-2) was homozygous for the minor allele at each marker (T2 and X2), however, the proposita and one sister carried only the major allele, which was inherited from the father. These results suggested that a deletion involving both markers could be present, and was inherited from the mother to both daughters. Quantitative multiplex PCR confirmed the deletion in female carriers, involving at least exons 12 to 17. DNA studies of cultured amniotic fluid cells at 14 weeks gestation, by amplification of specific Y-chromosome sequences, followed by multiplex PCR, lead to the diagnosis of a male fetus affected by DMD.

Cytogenetics in acute lymphoblastic leukemia in Mexican children: an institutional experience

BACKGROUND

Cytogenetic studies in acute lymphoblastic leukemia (ALL) have identified numerical and structural chromosomal abnormalities related to the disease's pathophysiologic characteristics. These findings correlate with prognosis and response to treatment in ALL patients. The purpose of this study was to define the frequency of chromosomal abnormalities in a group of Mexican children with ALL and to compare these data with those reported in the literature.

METHODS

Bone marrow chromosome studies with GTG bands were performed in 150 pediatric patients with ALL who were naive to antileukemic treatment and aged from 5 months to 16 years; the majority was diagnosed as L1.

RESULTS

Among 131 patients, 30 (22.9%) karyotypes were normal and the remaining 101 (77.1%) had abnormal karyotypes with numerical and/or structural abnormalities. Among patients with numerical abnormalities, the most frequent karyotypes were hyperdiploidy with 51-65 chromosomes (30 patients) and hyperdiploidy with 47-50 chromosomes (18 patients). Among recurrent, non-random, and primary structural abnormalities, the most frequent was t(9;22), followed by t(1;19). Aberrations involving band 11q23 were not detected, and only one of two patients with L3 had the t(8;14). Of the secondary non-random abnormalities, dup(1q), del(6q), and i(7)(q10) were found.

CONCLUSIONS

The frequency and type of chromosomal abnormalities found was comparable to those reported in the literature with similar methodology and pediatric populations; however, the number of cases analyzed should be increased to create a database of Mexican children with ALL, and several patients require molecular analysis to identify chromosomal abnormalities not detected through conventional cytogenetic studies.

Can seizures be the only manifestation of transient ischemic attacks? A report of four cases

Several studies have investigated the frequency of epileptic seizures following ischemic strokes and transient ischemic attacks (TIAs). Little attention has been paid to the possibility that seizures may be precipitated by TIAs. We examined if seizures can be the only symptom of a TIA and how often this might occur. We performed a retrospective analysis of clinical charts and electroencephalograms of 160 consecutive patients evaluated for a first-ever seizure from January 1997 to December 1999 at Belluno General Hospital. From January to May 2000, 19 more first-ever seizure patients were evaluated directly. Four patients (2%) had seizures in the presence of important risk factors for ischemic stroke (atrial fibrillation in two patients, atrial fibrillation and ventricular mural thrombus in one patient, hemodynamically significant left carotid stenosis in one patient). Seizures were not accompanied by other neurological deficits or brain lesions on CT or MRI. As risk factors for brain ischemia are frequent in the general population not developing seizures, our results do not prove that the occurrence of seizures was more than casual in these patients. Yet they indicate that in a small percentage of patients, seizures can occur in a context highly suggestive of TIA, with no other focal deficits.

Spectrum of CFTR mutations in Mexican cystic fibrosis patients: identification of five novel mutations (W1098C, 846delT, P750L, 4160insGGGG and 297-1G-->A)

We have analyzed 97 CF unrelated Mexican families for mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Our initial screening for 12 selected CFTR mutations led to mutation detection in 56.66% of the tested chromosomes. In patients with at least one unknown mutation after preliminary screening, an extensive analysis of the CFTR gene by single stranded conformation polymorphism (SSCP) or by multiplex heteroduplex (mHET) analysis was performed. A total of 34 different mutations representing 74.58% of the CF chromosomes were identified, including five novel CFTR mutations: W1098C, P750L, 846delT, 4160insGGGG and 297-1G-->A. The level of detection of the CF mutations in Mexico is still lower than that observed in other populations with a relatively low frequency of the deltaF508 mutation, mainly from southern Europe. The CFTR gene analysis described here clearly demonstrated the high heterogeneity of our CF population, which could be explained by the complex ethnic composition of the Mexican population, in particular by the strong impact of the genetic pool from southern European countries.

Ataxia-pancytopenia syndrome

We report on a Mexican girl who developed cerebellar ataxia at age 3 years and pancytopenia at age 13 years. Cerebral computed tomography scan and magnetic resonance imaging showed evidence of severe cerebellar atrophy. Telangiectasias were not present; immunoglobulins and alpha-fetoprotein levels were normal. Cytogenetic studies showed no evidence of spontaneous chromosome aberrations, a normal rate of diepoxybutane (DEB) and mitomycin C (MMC)-induced chromosome aberrations, but an increased response to bleomycin. The phenotype support the diagnosis of ataxia-pancytopenia syndrome, although monosomy of chromosome 7 was not found in bone marrow. The cytogenetic studies suggest that this may be a chromosomal instability disorder.

[The content and limits of consent to a medical procedure]

The bases of legality for any medical-surgical activity aimed at a therapeutical-diagnostic purpose is the consent of the patient. Such a consent must comply with some requirements of validity, first of all the owner of this right must be able to realize the significance of the assertion of his will. Besides, the awareness of the consent assumes that the surgeon should make a complete and detailed planning of the operation, with a clear reference to any possible hazard, as well as to any possible after-effects, as far as either the intellectual level or the motivity of the patient are concerned. After having examined the various laws covering, the legal, doctrinal and jurisprudential views, authors defines the aspects of the therapeutical treatment. The differences between a free decision and a true informed consent are outlined as well as the extension and the expression of same. It is particularly analysed the relationship between capacity and competence to get the juridical right. The question of understanding which is the best way to respect individual freedom, often reduced to a virtual level form a pathological restriction of individual autonomy, is still open. Moreover, the consent may really be effective only if it is specific, the is aimed at a well definite and accurate therapeutical act. Authors agrees with the criminalist interpretation that the medical surgical activity, out of consent of the patient, can give form to personal voluntary injury. In case of medical surgical treatment different from that previously agreed and out of a situation of therapeutic flagrant necessity, the authors are of the opinion that the inquiry has to concern the medical behaviour in order to estimate the medical surgical treatment as personal voluntary injury or as personal negligent injury. Some reasoned evaluations on the problem were considered at the end of the article.

Mexican geneticists' views of ethical issues in genetics testing and screening. Are eugenic principles involved?

Herein we discuss Mexican geneticists' views of ethical issues in genetic testing and screening, analyzing whether eugenic principles are involved in this activity. The information was obtained from a comprehensive survey on genetics, ethics, and society organized by Wertz and Fletcher in 1993, in which 37 nations participated. The responses to 21 questions from 64 out of 89 (72%) geneticists invited to participate are analyzed in this paper. The questions were practically the same as those answered recently by a group of Chinese geneticists (Mao X. Chinese geneticists' views of ethical issues in genetic testing and screening: evidence for eugenics in China. Am J Hum Genet 1998: 63: 688-695), who work in a country where the furtherance of eugenic principles is considered to be the goal of human genetics. We concluded that although there are many similarities in the answers from both countries, this is not indicative of Mexican geneticists pursuing eugenic goals because: a) there is no coercion involved; and b) there is no intention of improving the gene pool.