Sensitive physiological readouts to evaluate countermeasures for lipopolysaccharide-induced lung alterations in mice

Despite decades of research, studies investigating the physiological alterations caused by an acute bout of inflammation induced by exposing the lung to lipopolysaccharide have yielded inconsistent results. This can be attributed to small effects and/or a lack of fitted physiological testing. Herein, a comprehensive investigation of lung mechanics was conducted in 270 male C57BL/6 mice at 24, 48 or 96 h after an intranasal exposure to saline or lipopolysaccharide at either 1 or 3 mg/kg (30 mice per group). Traditional techniques that probe the lung using small-amplitude perturbations (i.e., oscillometry) were used, together with less conventional and new techniques that probe the lung using maneuvers of large amplitudes. The latter include a partial and a full-range pressure-volume maneuvers to measure quasi-static elastance, compliance, total lung volume, vital capacity and residual volume. The results demonstrate that lung mechanics assessed by oscillometry was only slightly affected by lipopolysaccharide, confirming previous findings. In contradistinction, lipopolysaccharide markedly altered mechanics when the lung was probed with maneuvers of large amplitudes. With the dose of 3 mg/kg at the peak of inflammation (48 h post-exposure), lipopolysaccharide increased quasi-static elastance by 26.7% (p<0.0001), and decreased compliance by 34.5% (p<0.0001). It also decreased lung volumes, including total lung capacity, vital capacity and residual volume by 33.3%, 30.5% and 43.3%, respectively (all p<0.0001). These newly reported physiological alterations represent sensitive outcomes to efficiently evaluate countermeasures (e.g., drugs) in the context of several lung diseases.

Effects of airway smooth muscle contraction and inflammation on lung tissue compliance

There are renewed interests in using the parameter K of Salazar-Knowles' equation to assess lung tissue compliance. K either decreases or increases when the lung's parenchyma stiffens or loosens, respectively. However, whether K is affected by other common features of respiratory diseases, such as inflammation and airway smooth muscle (ASM) contraction, is unknown. Herein, male C57BL/6 mice were treated intranasally with either saline or lipopolysaccharide (LPS) at 1 mg/Kg to induce pulmonary inflammation. They were then subjected to either a multiple or a single-dose challenge with methacholine to activate ASM to different degrees. A quasi-static pressure-driven partial pressure-volume maneuver was performed before and after methacholine. The Salazar-Knowles' equation was then fitted to the deflation limb of the P-V loop to obtain K, as well as the parameter A, an estimate of lung volume (inspiratory capacity). The fitted curve was also used to derive the quasi-static elastance (E_st) at 5 cmH₂O. The results demonstrate that LPS and both methacholine challenges increased E_st. LPS also decreased A, but did not affect K. In contradistinction, methacholine decreased both A and K in the multiple-dose challenge, while it decreased K but not A in the single-dose challenge. These results suggest that LPS increases E_st by reducing the open lung volume (A) and without affecting tissue compliance (K), while methacholine increases E_st by decreasing tissue compliance with or without affecting lung volume. We conclude that lung tissue compliance, assessed using the parameter K of Salazar-Knowles' equation, is insensitive to inflammation but sensitive to ASM contraction.

Intranasal versus intratracheal exposure to lipopolysaccharides in a murine model of acute respiratory distress syndrome

Due to frequent and often severe lung affections caused by COVID-19, murine models of acute respiratory distress syndrome (ARDS) are increasingly used in experimental lung research. The one induced by a single lipopolysaccharide (LPS) exposure is practical. However, whether it is preferable to administer LPS intranasally or intratracheally remains an open question. Herein, female C57Bl/6 J mice were exposed intranasally or intratracheally to one dose of either saline or 3 mg/kg of LPS. They were studied 24 h later. The groups treated with LPS, either intranasally or intratracheally, exhibited a pronounced neutrophilic inflammation, signs of lung tissue damage and protein extravasation into the alveoli, and mild lung dysfunction. The magnitude of the response was generally not different between groups exposed intranasally versus intratracheally. However, the variability of some the responses was smaller in the LPS-treated groups exposed intranasally versus intratracheally. Notably, the saline-treated mice exposed intratracheally demonstrated a mild neutrophilic inflammation and alterations of the airway epithelium. We conclude that an intranasal exposure is as effective as an intratracheal exposure in a murine model of ARDS induced by LPS. Additionally, the groups exposed intranasally demonstrated less variability in the responses to LPS and less complications associated with the sham procedure.

Ultrasound arterial anomalies in patients exposed to nilotinib therapy for chronic myeloid leukemia

INTRODUCTION

Patients exposed to nilotinib for chronic myeloid leukemia (CML) appear to be at risk of arterial complication. The prevalence and aspect of ultrasound asymptomatic arterial lesions are unknown.

OBJECTIVE

To describe prevalence and characteristics of ultrasound arterial anomalies in patients treated with nilotinib for CML.

METHODS

Patients treated with nilotinib from 2006 to 2015 in the department of the Paoli-Calmettes Institute, Marseille, were included retrospectively. A vascular ultrasound screening was carried out from 2010. The arterial lesions at the first examination were described: plaque and its echogenicity, stenosis or occlusion. A vascular arterial anomaly (VAA) was defined by the presence of a clinical and/or ultrasound anomaly. Patients with or without VAA at initial vascular examination were compared using bivariate and multivariate analysis.

RESULTS

74 patients were included (51.4% men, mean age 54.5 years); 25 patients had ultrasound arterial anomalies (33.8%). Carotid bulb was the most involved territory (44%). Arterial anomalies were: 88% plaques, 44%>50% stenosis and 12% occlusion. 72.7% plaques were echolucent or hypoechogenic. A VAA was present in 25 patients with initial vascular evaluation (33.8%). Patients with VAA at baseline were significantly older (64.9 vs 49.3, P<0.001), older at nilotinib initiation (60.8 vs 46.5, P<0.001), with more arterial hypertension (40% vs 12.2%, P=0.01), with more cardiovascular risk factors (P=0.03). In patient with no cardiovascular risk factor 12.5% had VAA (n=24).

CONCLUSION

Nilotinib seems to be associated to arterial lesions of unstable lipid-like appearance. The most involved arterial territory was the carotid bulb and the most common lesion was echolucent or hypoechogenic plaque. VAA can occur in patients without cardiovascular risk factors. This result encourages us to systematically screen and follow all patients exposed to nilotinib even those without cardiovascular risk factors.

Coronary lesion complexity in patients with familial hypercholesterolemia hospitalized for an acute myocardial infarction: data from the French RICO Survey

Background

Although patients with familial heterozygous hypercholesterolemia (FH) are at high risk of early myocardial infarction (MI), coronary artery disease (CAD) burden of FH patients with acute MI remains to be investigated.

Methods

All consecutive patients hospitalized for an acute MI in a multicenter database (RICO) from 2012–2017 who underwent coronary angiography were considered. FH (n=86) was diagnosed using Dutch Lipid Clinic Network criteria (score ≥6). The angiographic features of FH patients were compared with patients without FH (score 0–2) (n=166), after matching for age, sex and diabetes (1:2).

Results

When compared with patients without FH, patients with FH had higher prevalence of personal and familial history of CAD (17 vs 5%, and 74 vs 5%, p=0.002 and p&lt;0.001, respectively), and hypertension (54 vs 36%, p=0.006). Chronic statin treatment was used in only 45% of FH patients. At coronary angiography, FH had increased extent of CAD (SYNTAX score 11 (4–21) vs 8 (3–16), p=0.049) and multivessel disease (58% vs 43%, p=0.021). Significant stenosis was more frequent in left and right marginal coronary arteries. FH patients showed a trend toward more complex lesions, with less thrombus (28 vs 39%, p=0.076), but a 2 times higher rate of bifurcation lesions and calcifications (23 vs 12% and 20 vs 10%, p=0.021 and p=0.036).

Conclusions

This study addressing the coronary lesions features of FH patients with acute MI shows that FH patients had more severe CAD burden, and were characterized by complex anatomy features.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): ARS Bourgogne Franche Comté, CHU Dijon Bourgogne

Descriptive study of the general practitioners' perception of direct oral anticoagulants and the risk of genital bleeding in women of childbearing age

AIM OF THE STUDY AND PATIENTS

Direct oral anticoagulants (DOA) tend to replace antivitamins K (VKA). The incidence of major and minor hemorrhages is higher in women, a difference potentially linked to genital hemorrhages. The objective is to assess the practices and perception of general practitioners of the use of oral anticoagulant therapy in women of childbearing age.

MATERIALS AND METHODS

Descriptive, observational, transversal and monocentric study. An 11-items questionnaire was sent to 900 randomized general practitioners, assessing the type of patient, the type of anticoagulant prescribed, the management of genital bleeding, and the assessment of the quality of life of anticoagulated patients.

RESULTS

DOA were the most prescribed anticoagulants. Genital hemorrhage was the second leading cause of minor hemorrhage. Most doctors (60.6%) believed they were due to VKAs. 25% reported an alteration in the quality of life of patients following these genital hemorrhages and 47.5% addressed this subject in consultation.

CONCLUSION

Our study suggests that, according to the general practitioners interviewed, genital hemorrhage is more frequent on VKA than on DOA in women of reproductive age, which is contradictory with the data in the literature. The probably taboo subject is rarely mentioned in consultation and is responsible for a deterioration in the quality of life in these young patients. No recommendation exists on the management of this type of genital hemorrhage in these women. An algorithm is proposed for their management.

Variations in coil temperature/power and e-liquid constituents change size and lung deposition of particles emitted by an electronic cigarette

Electronic cigarette uses propylene glycol and glycerol to deliver nicotine and flavors to the lungs. Given the hundreds of different brands, the thousands of flavors available and the variations in nicotine concentrations, it is likely that electronic cigarette settings and e-liquid composition affect the size distribution of particles emitted and ultimately pulmonary deposition. We used the inExpose e-cigarette extension to study two separate modes of operation of electronic cigarettes, namely power-controlled and the temperature-controlled. We also assessed several e-liquids based on propylene glycol and glycerol concentrations, nicotine content, and selected monomolecular flavoring agents (menthol, vanillin, and maltol). Particle size distribution was measured using a Condensation Particle Counter and a Scanning Mobility Particle Sizer spectrometer. Lung deposition was predicted using the International Commission on Radiological Protection model. For all resistance coils, increase in power delivery generated larger particles while maintaining a higher coil temperature generated smaller particles. Increase in glycerol concentration led to the generation of larger particles. With regard to flavors, we showed that despite minor effect of menthol and maltol, vanillin dramatically increased particle size. Presence of nicotine also increased particle size. Finally, particles emitted by the electronic cigarette were predicted to mainly deposit in the alveoli and conditions generating larger particle sizes led to a reduction in predicted lung deposition. This study shows that coil temperature, propylene glycol and glycerol concentrations, presence of nicotine, and flavors affect the size of particles emitted by an electronic cigarette, directly affecting predicted lung deposition of these particles.

New Direct Assay of Free Protein S Antigen Applied to Diagnosis of Protein S Deficiency

Congenital deficiencies of protein S (PS) are associated with thrombophilia. Their characterization and classification have been hampered by the complex physiology of the protein C-protein S system and the poor standardization and reliability of laboratory assays. The free active form of protein S is usually determined by immunoassay using polyclonal antibodies in the plasma supemate after polyethyleneglycol (PEG) precipitation. A new one step ELISA using two monoclonal antibodies specific for distinct epitopes of the free form of protein S has been developed for the direct measurement of free PS in untreated plasma.

We have tested two ELISA assays for free PS. One assay was based on the PEG precipitation (Asserachrom PS®, Stago, Asnières, France) whereas the other was a one step ELISA assay (Asserachrom® free PS, Stago). Values were obtained in 35 PS deficient patients recruited among 500 consecutive patients evaluated by the laboratory for diagnosis of congenital disorders of coagulation. Values were compared to those obtained in 50 patients with no PS deficiency matched for age and sex with the PS deficient patients as well as in 33 normal subjects and in 12 pregnant women. Strong correlation was found between the two tests (r = 0.81, p<10-5) in the entire population (n = 130), as well as in the separate groups. The new one step ELISA was more accurate than the PEG free PS determination. Determination of PS activity and antigens allowed us to separate quantitative and qualitative deficiencies. Among the qualitative deficiencies, isolated decrease in PS activity was the most frequent defect observed (66%). This fact questions the substitution of PS activity assays by the one step antigenic free PS ELISA assay.

Assessment of Respiratory Function in Conscious Mice by Double-chamber Plethysmography

Air volume changes created by a conscious subject breathing spontaneously within a body box are at the basis of plethysmography, a technique used to non-invasively assess some features of the respiratory function in humans as well as in laboratory animals. The present article focuses on the application of the double-chamber plethysmography (DCP) in small animals. It provides background information on the methodology as well as a detailed step-by-step procedure to successfully assess respiratory function in conscious, spontaneously breathing animals in a non-invasive manner. The DCP can be used to monitor the respiratory function of multiple animals in parallel, as well as to identify changes induced by aerosolized substances over a chosen time period and in a repeated manner. Experiments on control and allergic mice are used herein to demonstrate the utility of the technique, explain the associated outcome parameters, as well as to discuss the related advantages and shortcomings. Overall, the DCP provides valid and theoretically sound readouts that can be trusted to evaluate the respiratory function of conscious small animals both at baseline and after challenges with aerosolized substances.

Risk assessment of venous thrombosis in families with known hereditary thrombophilia: the MARseilles-NImes prediction model

BACKGROUND

Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible.

OBJECTIVES

To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia.

PATIENTS/METHODS

1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score.

RESULTS

The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method.

CONCLUSIONS

With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

Risk assessment of venous thrombosis in families with known hereditary thrombophilia: the MARseilles-NImes prediction model

BACKGROUND

Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible.

OBJECTIVES

To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia.

PATIENTS/METHODS

1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score.

RESULTS

The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method.

CONCLUSIONS

With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

Clozapine augments delta, theta, and right frontal EEG alpha power in schizophrenic patients

Objective. To explore the Quantitative EEG (QEEG) effects of established clozapine therapy regimes compared to those of previous ineffective antipsychotic regimes among 64 chronic (DSM-IV) schizophrenic patients. Methods. Data from 20 EEG channels referenced to linked ears were collected before and during maintenance clozapine therapy (mean duration 1.4 years). Absolute power was calculated in six frequency bands: delta (0.4–3.6 Hz), theta (4.2–7.8 Hz), alpha (8.2–11.8 Hz), beta1 (12.2–15.8 Hz), beta2 (16.2–19.8 Hz), and beta3 (20.2–23.8 Hz). Results. Clozapine augments power globally in the delta and theta bands, but this effect is more pronounced over frontal areas. Beta3 power was reduced. Alpha showed a frontal increase, more pronounced in the right, coupled with a posterior decrease with no net change in overall power. Conclusion. The demonstration of a significant clozapine-induced alpha topographic shift frontally and to the right is a novel discovery that may serve to encourage further investigations of subcortical structures in attempts to better understand the diverse aetiologies and optimal treatments of the schizophrenias.

Antiepileptic drugs modify power of high EEG frequencies and their neural generators

BACKGROUND

The clinical and molecular effects of antiepileptic drugs (AEDs) have been extensively investigated. Much less is known about their effects on human electrophysiology.

METHODS

Topographic analysis in the frequency domain has been used to analyze 104 electroencephalogram (EEG) epochs of 52 patients presenting with first-ever generalized seizure, with normal MRI and EEG. Patients were treated with valproate, arbamazepine, or lamotrigine in monotherapy (each group n = 13). Thirteen patients without medication served as a control group.

RESULTS

Carbamazepine and lamotrigine, both sodium-channel modulators, altered brain topography in the gamma range in the same frequency bands (50-60 Hz). Valproate, which has multiple actions on sodium and calcium channels as well as GABA turnover, modified brain topography in the low gamma range (30-40 Hz). No such changes were found in the control group. For all AEDs, the neural generators were shifted more anteriorly in medial temporal through to inferior frontal regions.

CONCLUSION

Decreased gamma-power and anterior shift of neural generators after AED introduction reflect AED influence on human electrophysiology.

[Aortic bioprosthesis implanted percutaneously: three year follow up]

Percutaneous implantation of a bioprosthesis for the treatment of degenerative aortic stenosis ushered in a new era for interventional cardiology, and now represents the best therapeutic option for a growing number of patients for whom surgical aortic replacement would be too risky. This is the case in about a third of symptomatic patients affected. Between 2003 and 2005, we performed initial feasibility studies (I-REVIVE and RECAST) in Rouen, on non-operable patients in a critical state, included for purely compassionate reasons. The valve used was a pericardial bioprosthesis mounted in an expandable balloon stent. The mean age of the patients was 80 years, all had multiple co-morbidity and had been turned down by the cardiac surgeons. In 33 of the 36 included patients, the technique was attempted by the anterograde trans-septal approach (n=27, success rate 80%) or by the retrograde arterial route (n=7, success rate 57%). Echocardiography following implantation revealed a final aortic surface area of 1.70 cm2 and a transvalvular gradient of 9 mmHg. A significant paravalvular aortic leak was noted in 5 cases. There were 6 deaths by 1 month, related to the procedure, and 10 deaths by 6 months, from non-cardiac causes and not related to the procedure. There was no occurrence of coronary occlusion, secondary displacement or dysfunction of the prosthesis. In December 2006, 8 patients reached 2 years of follow up, and two others reached 3 years, symptom free and still with an unchanged valvular function. Significant technological improvements have made the technique simpler, quicker and safer, with very much improved short and long term results. The new trans-apical approach is under evaluation with some promising initial results. More than 280 patients have been implanted to date. Other implantable prostheses are under evaluation. This therapeutic modality looks likely to develop rapidly, and in the near future it should offer a new and optimal solution for all high surgical risk or non-operable patients.

[Revascularisation of unprotected left main coronary artery disease: an update]

Coronary bypass grafting is the reference treatment of unprotected left main coronary disease. Nevertheless, the experience of invasive cardiologists and the introduction of active stents make angioplasty possible in selected cases. Only the results of controlled clinical trials (SYNTAX trial currently under way) will enable physicians to choose the most appropriate method of revascularisation for their patients.

A founder haplotype for autosomal dominant sensory ataxia in Eastern Canada

We present phenotypic and genotypic data for an additional family with autosomal dominant sensory ataxia, a disease characterized by gait difficulties associated with diminished sensation in the limbs and areflexia. The same disease haplotype spanning the entire SNAX1 locus is observed in affected members of this second family, enabling the locus to be reduced to a 7.3-cM interval.

Genetic susceptibility to MS: a second stage analysis in Canadian MS families

Four published genome screens have identified a number of markers with increased sharing in multiple sclerosis (MS) families, although none has reached statistical significance. One hundred and five markers previously identified as showing increased sharing in Canadian, British, Finnish, and American genome screens were genotyped in 219 sibling pairs ascertained from the database of the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). No markers examined met criteria for significant linkage. Markers located at 5p14 and 17q22 were analyzed in a total of 333 sibling pairs and attained mlod scores of 2.27 and 1.14, respectively. The known HLA Class II DRB1 association with MS was confirmed (P<0.0001). Significant transmission disequilibrium was also observed for D17S789 at 17q22 (P=0.0015). This study highlights the difficulty of searching for genes with only mild-to-moderate effects on susceptibility, although large effects of specific loci may still be present in individual families. Future progress in the genetics of this complex trait may be helped by (1) focussing on more ethnically homogeneous samples, (2) using an increased number of MS families, and (3) using transmission disequilibrium analysis in candidate regions rather than the affected relative pair linkage analysis.

Water and soil pollution in vineyards of central Thailand

Very intensive cultivation systems have been developed in the delta of the Chao Phraya River for about a century. The objective of the study was to determine the fate of the fertilisers and pesticides applied to vineyards grown on raised beds. Water samples were collected from the outlet of a vineyard to determine the discharge of pollutants in the canal. The accumulation of elements in the soil was investigated by analysing soil samples from different fields. Fertilisation was estimated at 670 kg N, 300 kg P, and 560 kg K year(-1) ha(-1). Insecticides and fungicides were applied every four days on average, using up to 23 different molecules. Little N and no P were discharged in the canals in solution and discharge in suspension was minor. Pesticides were detected in 36% of the water samples. The topsoil contained 1600 mg kg(-1) Bray II P, 936 mg kg(-1) exchangeable K, 170 mg kg(-1) total Cu, and 167 mg kg(-1) total Zn. Pesticides were detected in 62% of the fruits after peeling. Overuse of fertilisers did not lead to water pollution, but overuse of pesticides resulted in pollution of the water bodies and of the fruits. Most applied elements accumulated in the soil, resulting in high values of P, K, Cu, and Zn.

Electrical dose and seizure threshold: relations to clinical outcome and cognitive effects in bifrontal, bitemporal, and right unilateral ECT

In patients allocated blindly and randomly to receive bitemporal, right unilateral, or bifrontal electroconvulsive therapy, seizure length, electrophysiologic characteristics (dynamic impedance, seizure threshold, and changes in threshold), and the degree of suprathreshold stimulation were recorded. The relations of these variables to clinical outcome and cognitive effects were determined. There were no differences in seizure length between groups, and there were no significant correlations between seizure length and any measure of clinical response. There were substantial differences between the groups in mean charge per treatment, with the right unilateral group receiving lower doses than either bilateral group. Convulsion time was inversely related to applied charge and the rate of increase in charge. There were no significant correlations between impedance, charge, energy, or rate of increase in charge on the one hand, and clinical improvement on the other. The increase in threshold during the course of treatment was not related to clinical change. Cognitive impairment was related to electrical dose only in the bifrontal group, which showed the least degree of treatment-induced intellectual dysfunction. Compared with bitemporal or right unilateral treatment, bifrontal electroconvulsive therapy yields the best ratio of benefits to side effects and should be given at threshold level to minimize cognitive loss.

Clinical and electrophysiological study in French-Canadian population with Charcot-Marie-tooth disease type 1A associated with 17p11.2 duplication

BACKGROUND

The aim of the present study was to examine the frequency and the phenotypic manifestations in a French-Canadian population with a chromosome 17p11.2 duplication (Charcot-Marie-Tooth type 1A, CMT-1A).

METHODS

Molecular analysis were performed by Southern blot using pVAW409R3a probe. Clinical evaluation was carried out according to the scale defined by the European HMSN Consortium.

RESULTS

The frequency of duplication was found to be similar in the adult (70.8%) and pediatric (72.7%) populations. Onset of symptoms occurred before 20 years of age in 85.7% of adult cases and before the age of 5 in 80% of the pediatric cases. The classical CMT syndrome was observed in 77% of the cases and the syndrome was associated with additional features in 15% of cases in the adult population. All the children presented with classical CMT syndrome with no additional features. There was a significant correlation between the disability score and the duration of the disease but no correlation was found between median nerve conduction velocity and the functional handicap, the age at onset or the duration of the disease. In one family, there was a very conspicuous anticipation over five observed generations.

CONCLUSION

This study reveals that the age at onset, the clinical and electrophysiological variability as well as the functional disability variations in a French-Canadian population did not differ from those reported in other populations.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay

A form of autosomal recessive spastic ataxia unique to the Charlevoix-Saguenay area was clinically identified 20 years ago in patients from that region. This region of Québec, Canada, was once considered a genetic isolate. First noted at gait initiation, signs of ataxia slowly progress along with spasticity of the four limbs, slurred speech, and followed by distal amyotrophy. Early diagnosis relies on the presence of prominent myelinated fibers embedding retinal blood vessels at funduscopy and marked saccadic alteration of ocular smooth pursuit. Imaging of the posterior fossa shows cerebellar vermis atrophy and nerve conduction studies reveal loss of sensory and reduced motor conduction velocities. The clinical features are consistent with a developmental defect in myelination of both retinal and peripheral nerve fibers. The cause of this defect and the progressive axonal degeneration in the corticospinal and spinocerebellar tracts, as well as in the peripheral nerves is still unknown. Results of recent molecular genetic linkage analysis have located the gene locus to chromosome 13q12. Further research is needed to define where this hereditary spastic ataxia stands in the classification of the early onset spinocerebellar degenerations.

Recent studies on oculopharyngeal muscular dystrophy in Québec

In 1990, we launched a major study to ascertain the clinical picture of OPMD in Québec and to identify large families for linkage analysis. In 14 patients, the chromosomes were karyotyped to eliminate any deletion or translocation. Relevant family information and clinical data were computerized and correlations were sought for the age of onset, the identification of the first symptom and the distribution of weakness. A simple test to detect dysphagia was validated. Twenty-one families have taken part in the study, which led to our localization of the gene in 1995 [Brais B, Xie Y-G, Sanson M, et al. Hum Mol Genet 1995; 4:429-434]. At least one case in each family underwent muscle biopsy to confirm the presence of the typical nuclear filaments found in OPMD. Electrodiagnostic and pathologic studies were also conducted to better understand the disease process. An illustrative case is presented.

A full genome search in multiple sclerosis

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

New direct assay of free protein S antigen applied to diagnosis of protein S deficiency

Congenital deficiencies of protein S (PS) are associated with thrombophilia. Their characterization and classification have been hampered by the complex physiology of the protein C-protein S system and the poor standardization and reliability of laboratory assays. The free active form of protein S is usually determined by immunoassay using polyclonal antibodies in the plasma supernate after polyethyleneglycol (PEG) precipitation. A new one step ELISA using two monoclonal antibodies specific for distinct epitopes of the free form of protein S has been developed for the direct measurement of free PS in untreated plasma. We have tested two ELISA assays for free PS. One assay was based on the PEG precipitation (Asserachrom PS, Stago, Asnières, France) whereas the other was a one step ELISA assay (Asserachrom free PS, Stago). Values were obtained in 35 PS deficient patients recruited among 500 consecutive patients evaluated by the laboratory for diagnosis of congenital disorders of coagulation. Values were compared to those obtained in 50 patients with no PS deficiency matched for age and sex with the PS deficient patients as well as in 33 normal subjects and in 12 pregnant women. Strong correlation was found between the two tests (r = 0.81, p < 10(-5)) in the entire population (n = 130), as well as in the separate groups. The new one step ELISA was more accurate than the PEG free PS determination. Determination of PS activity and antigens allowed us to separate quantitative and qualitative deficiencies. Among the qualitative deficiencies, isolated decrease in PS activity was the most frequent defect observed (66%). This fact questions the substitution of PS activity assays by the one step antigenic free PS ELISA assay.