Diagnostic value of exhaled nitric oxide to detect interstitial lung disease in systemic sclerosis

BACKGROUND AND AIM

Increased alveolar concentration of nitric oxide (CA(NO)) is related to the severity of interstitial lung disease (ILD) in systemic sclerosis (SSc). However, cut-off levels of CA(NO) to rule out, or to rule in, the presence of ILD in individual patients are unknown. We aimed to assess the validity of CA(NO) for the diagnosis of ILD in SSc and to determine the thresholds of CA(NO) that can be used in clinical practice to predict the likelihood of ILD in SSc.

METHODS

Lung HRCT scan, PFTs and partitioned exhaled NO measurements were performed in 65 consecutive SSc patients. ILD was diagnosed on pulmonary HRCT according to the presence of ground glass or reticular opacities. Diagnostic performance of CANo for ILD diagnosis was assessed using ROC curves.

RESULTS

38 out of 65 SSc patients had ILD. CA(NO), at a cut-off level of 4.3 ppb, had a sensitivity and specificity for the diagnosis of ILD of 87% (95% CI: 77 to 99) and 59% (95% CI: 41 to 78), respectively. The same cut-off level of CA(NO) could detect impairment of gas exchange with a sensitivity and specificity of 78% (95% CI: 67 to 90) and 73% (95% CI: 46 to 99), respectively. Moreover, ILD could be ruled in (positive predictive value > 95%) when CA(NO) > or = 10.8 ppb, and ruled out C(ANO) values < or = 3.8 ppb (negative predictive value > 95%).

CONCLUSION

CA(NO) could be a valid non-invasive biological marker of ILD in SSc, and be of use in clinical practice.

A Role For Wind-Up in Trigeminal Sensory Processing: Intensity Coding of Nociceptive Stimuli in the Rat

Wind-up is a progressive, frequency-dependent increase in the excitability of trigeminal and spinal dorsal horn wide dynamic range (WDR) nociceptive neurons evoked by repetitive stimulation of primary afferent nociceptive C-fibres. The correlate of wind-up in humans is temporal summation, which is an increase in pain perception to repetitive constant nociceptive stimulation. Although wind-up is widely used as a tool for studying the processing of nociceptive information, including central sensitization, its actual role is still unknown. Here, we recorded from trigeminal WDR neurons using in vivo electrophysiological techniques in rats and assessed the wind-up phenomenon in response to stimuli of different intensities and frequencies. First, we found that the amplitude of C-evoked responses of WDR neurons to repetitive stimulation increased progressively to reach a peak, then consistently showed a stable or slightly decreasing plateau phase. Only the first phase of this time course fitted in with the wind-up description. Therefore, to assess wind-up, we measured a limited number of initial responses. Second, we showed that wind-up, i.e. the slope of the frequency-dependent increase in the response to C-fibre stimulation, was linearly correlated to the stimulus intensity. Intensities of brief C-fibre inputs were thus coded into frequencies of action potentials by second-order neurons through frequency-dependent potentiation of the evoked responses. Third, wind-up also occurred at stimulation intensities below the threshold for C-evoked responses in WDR neurons, suggesting that wind-up can amplify subthreshold C-fibre inputs to WDR neurons. This might account for the observation that sparse, subliminal, neuronal activity in nociceptors can become painful via central integration of neural responses. Altogether, the present results show that wind-up can provide trigeminal WDR neurons with the capability to encode the intensity of short-duration orofacial nociceptive stimuli and to detect subthreshold nociceptive input. Thus, not only may wind-up play a physiological role in trigeminal sensory processing, but its enhancement may also underlie the pathophysiology of chronic orofacial pain conditions.

The p.Val66Met polymorphism in the BDNF gene protects against early seizures in Rett syndrome

OBJECTIVE

X chromosome inactivation and the MECP2 genotype do not provide the full explanations for the clinical differences between patients with Rett syndrome (RTT), suggesting the involvement of other factors. One MeCP2 target is the brain-derived neurotrophic factor (BDNF) gene. We investigated, according to the MECP2 genotype, the role of the BDNF functional polymorphism (Val66Met) on the severity of RTT.

METHODS

This polymorphism in BDNF was analyzed by PCR and dHPLC in 81 patients with RTT. We studied the association between the MECP2 and BDNF genotypes and the clinical features in each patient.

RESULTS

We found that some RTT features can be correlated with MECP2 genotypes. Missense mutations are associated with a more severe epileptic phenotype (early onset and drug resistance) than other mutations. Non-sense and late truncating mutations lead to a less severe phenotype regarding walking. The distribution of the Val66Met polymorphism was not significantly different between the different groups in regard to the severity of all tested symptoms. However, girls with RTT bearing the Val66Val genotype tend to present earlier seizures than girls with RTT bearing the Met66 allele. No girls with RTT with the Met66 allele presented early seizures.

CONCLUSIONS

Early onset of seizures is linked to the combined MECP2 and BDNF genotypes. The BDNF Met66 allele may protect against seizures, whereas missense mutations in the MBD of MECP2 are more frequently associated with early seizures.

The leucotriene receptor antagonist montelukast and the risk of Churg-Strauss syndrome: a case-crossover study

BACKGROUND

There has been some concern that leucotriene receptor antagonists might precipitate the onset of Churg-Strauss syndrome (CSS). A study was undertaken to investigate the relationship between the leucotriene receptor antagonist montelukast and the onset of CSS.

METHODS

Medication histories of 78 patients with CSS from France and Germany were retraced by questioning the patients, treating physicians and dispensing pharmacists, and from medical records. Using a case-crossover research design, exposures to montelukast and other asthma medications during the 3-month "index" period immediately preceding the onset of CSS were compared with those of four previous 3-month "control" periods. Odds ratios (ORs) were computed by conditional logistic regression.

RESULTS

The ORs for CSS onset were 4.5 (95% CI 1.5 to 13.9) for montelukast, 3.0 (95% CI 0.8 to 10.5) for inhaled long-acting beta(2) agonists, 1.7 (95% CI 0.5 to 5.4) for inhaled corticosteroids and 4.0 (95% CI 1.3 to 12.5) for oral corticosteroids. Montelukast exposure during control periods increased temporally over three consecutive calendar periods of CSS onset from 1999 to 2003 (p(trend) <0.0001).

CONCLUSION

Montelukast use was associated with a 4.5-fold higher risk of CSS onset within 3 months. However, the positive estimates obtained for other long-term asthma control medications suggest that this link might be confounded by a general escalation of asthma therapy before CSS onset. The association between montelukast and CSS observed in this study is probably also explained by the increasing use of this medication over time.

[Benefit of hip ultrasound in management of the limping child]

OBJECTIVE

To evaluate the contribution of sonography of the hip in the management of nontraumatic limping in children.

PATIENTS AND METHODS

Prospective study including children consulting for nontraumatic limping (n=93). These children had a clinical examination, a biological and imaging workup (pelvis x-rays (n=88), initial sonograph of the hip (n=93), and follow-up sonograph of the hip (n=29)).

RESULTS

Ninety-three children (69 boys, 24 girls) aged from 10 months to 13 years (median, 4 years) were included and divided into two groups: The sensitivity and specificity of sonography in establishing a serious diagnosis was 57% and 59%, respectively.

CONCLUSION

The advantage of systematic hip sonography is challenged in this study because of low sensitivity and specificity. Its main advantage seems to be in its negative results, which prompt other investigations.

[A strategy for therapy of depressive disorders and anxiety disorders by a health education intervention in medical consultations: the results of the APRAND program]

BACKGROUND

Studies devoted to the detection and treatment of anxiety and depression in adult populations show that at least 10% meet ICD10 criteria for an anxiety or a depressive disorder, but only half are diagnosed as such and only one third of those receive appropriate treatment. The goal of the APRAND program was to explore the possibility of improving management strategies via health education during doctors' visits.

METHODS

In 2001, EDF-GDF conducted an experimental program in which 21 physicians from its in-house health insurance program used the MINI mental state examination to screen for ICD10 criteria for anxiety and depressive disorders in 9743 employees on sick leave. A "here-elsewhere" epidemiologic study evaluated the program, recording the initial diagnoses and studying a year later the outcome of the persons identified with these disorders in 8 active centers (with prevention activities) and in 13 control centers (without prevention activities). The activities consisted of explanations of the disorders identified, delivery of the test results, delivery of leaflets based on the WHO guidelines, and strong recommendations to see a general practitioner, or a psychiatrist, or the occupational physician, if necessary. Logistic regressions compared the two groups, taking into account sex, age, geographic region, comorbidity, and medical care at screening.

RESULTS

Preventive activities were significantly associated with the disappearance at 1 year of depressive episodes (OR=1.93; CI 95%; 1.3-2.84) and of phobic or panic disorders (OR=1.98; CI 95%; 1.14-3.44). The only other variables affecting prognosis were age and sex. The probability of recovery or remission increased by 10 to 20% at active centers, according to age, sex and disorder. Moreover, the physicians reported that they learned a great deal from the program, which thus also improved their practices.

CONCLUSION

Diagnosis and prognosis of depressive episodes and phobic and panic disorders in adult populations can be improved by a preventive diagnostic and educational approach of the type used by APRAND during doctor's visits.

Fitting new technologies into the safety paradigm: use of microarrays in transfusion

Until the late 1990s, mandatory blood screening for transmissible infectious agents depended entirely on antigen/antibody-based detection assays. The recent emergence of Nucleic acid Amplification Technologies (NAT) has revolutionised viral diagnosis, not only by increasing the level of sensitivity but also by facilitating the detection of several viruses in parallel by multiplexing specific primers. In more complex biological situations, when a broad spectrum of pathogens must be screened, the limitations of these first generation technologies became apparent. High throughput systems, such as DNA Arrays, permit a conceptually new approach. These miniaturised micro systems allow the detection of hundreds of different targets simultaneously, inducing a dramatic decrease in reagent consumption, a reduction in the number of confirmation tests and a simplification of data interpretation. However, the systems currently available require additional instrumentation and reagents for sample preparation and target amplification prior to detection on the DNA array. A major challenge in the area of DNA detection is the development of methods that do not rely on target amplification systems. Likewise, the advances of protein microarrays have lagged because of poor stability of proteins, complex coupling chemistry and weak detection signals. Emerging technologies like Biosensors and nano-particle based DNA or Protein Bio-Barcode Amplification Assays are promising diagnostic tools for a wide range of clinical applications, including blood donation screening.