O-005 Reducing inter-observer and intra-observer variability of embryo quality assessment using deep learning

Study question

Does deep learning for embryo quality assessment reduce inter-observer variability?

Summary answer

An AUC of 87.65% was obtained for predicting blastocyst quality with a deep-learning algorithm trained by five embryologists who had good agreement between themselves

What is known already

Time-Lapse (TL) allows continuous observation of embryo development in a controlled and stable environment. Recently the use of deep learning, in particular convolutional neural networks have been introduced to enhance blastocyst image classification using the growing TL image and video data.

Study design, size, duration

A total of 409 embryos (5 images per embryo for a total of 2 045 images) were included in this retrospective study between 2016 and 2020.

Participants/materials, setting, methods

A machine-learning algorithm (Retinanet) was trained to recognize 2 045 blastocyst images from 409 embryos on 2560x1928 images and output 500x500 images with the blastocyst centered on the image. Five embryologists classified the blastocysts using Gardner’s grading system. Each image was associated with one final grade using a majority voting system. The dataset was split into a training and validation set (1 640 images plus data augmentation) and a testing set (405 images).

Main results and the role of chance

Fair agreement was found between the 5 embryologists when grading the embryo using Gardner’s grading system, with a maximum weighted kappa score of 39.60% reached.

As for the intra-observer variability, we show that for the same embryologist grading the same embryo after a 3 month “wash out” period, in 12% of the cases the embryologist changes the grade and the fate of the embryo, meaning that an embryo that was transferred/frozen during the first annotation period was discarded during the second one, or an embryo that was discarded during the first annotation period was transferred/frozen during the second one.

An Area Under the Curve (AUC) of 87.65% was obtained when testing the quality of 81 embryos (405 images) after training our algorithm on 54 038 images.

For external validation we tested the algorithm with annotations of the test set from embryologists coming from another fertility center. An AUC of 82.72% was obtained.

Limitations, reasons for caution

The scarce number of images available in our training set compared with data sets from other more consequent clinics, and the fact that the algorithm was trained by embryologists does not suppress variability entirely. The GoogLeNet algorithm was not fined tune and was used as is.

Wider implications of the findings

AI is showing precious value the field of embryology, from enhancing blastocyst quality prediction to removing inter-observer subjectivity. A possible evolution to our framework would be to predict the Gardner’s grading system for each morphological parameter.

Trial registration number

not applicable

P–793 Validation of French in vitro fertilization (IVF) guideline during Covid–19 pandemic by the research of Sars-Cov–2 RNA in the follicular fluid (FF) after egg retrieval

Study question

Is it possible to find viral Sars-Cov–2 RNA in FF of women undergoing treatment during Covid–19 pandemic that may compromise gamete and embryo safety?

Summary answer

No viral RNA was detected in tested FF of women undergoing IVF in compliance with recommendations. This was reassuring and supported good medical practice.

What is known already

Risks due to SARS-CoV–2 during IVF remain difficult to assess despite the screening recommended by French health authorities based on a symptom questionnaire of the couple (systematic testing by RT-PCR for the virus before egg retrieval (ER) is not mandatory). In this context, this is a real challenge for IVF laboratory to guarantee procedure, patients, gametes and embryos safety. Most studies have reported the absence of virus in sperm. No data are available for FF and only one study looked for the presence of the virus in oocytes of Covid-affected patients (Barragan M et al, 2020).

Study design, size, duration

Between June 17 and September 24, 2020, FF of consenting women were prospectively collected and symptom questionnaire recorded. During this period, women undergoing IVF in our center did not benefit from systematic PCR testing for the virus within 72 hours prior to ER through our health authorities’ recommendations. All collected FF were retrospectively tested to research viral RNA by RT-PCR and patients were recalled to answer an epidemiological follow-up questionnaire.

Participants/materials, setting, methods

For all couples, symptom questionnaires were prospectively recorded and verified at each step of IVF procedure. For all consenting women, a sample of 1 ml of FF was collected the day of ER and stored at –80 °C. After thawing, a Sars-Cov2 multiplex RT-PCR using CFX96 (Biorad*) was performed, after RNA extraction using Nimbus (Seegene*). A comprehensive epidemiological evaluation was made afterwards by phone interview and data were recorded and analyzed.

Main results and the role of chance

A total of 183 women was included out of the 214 treated during this period (85.5%). Retrospective epidemiological evaluation showed that 8 patients contracted Covid more than 2 months before the ER, 6 more than 2 months after and only one patient 1 month after ER (diagnosis based on pathognomonic signs as agueusia and anosmia or/and positive PCR ). We observed a prevalence of symptomatic Covid forms in our IVF population of 8.2% during a 6-month period surrounding their IVF cycle. Moreover, until the introduction of systematic testing by RT-PCR for the virus before ER since the end of September 2020, 3 patients have been cancelled out of the 403 planned for positive PCR despite a negative questionnaire, which represents a prevalence of asymptomatic forms on the day of the ER at 0.7%. All the 183 FF tested did not reveal any viral RNA detection, which was reassuring concerning our medical practice and patient compliance and transparency. The absence of detected viral RNA may be due to several reasons: 1) women were not infected the day of ER 2) women had an asymptomatic form of the disease with low viral load 3) FF is not a virus reservoir.

Limitations, reasons for caution

Not all patients were included (85.5%). Post-diagnosis stays uncertain because PCR tests at the beginning of the epidemic were not mandatory and hardly available.

Wider implications of the findings: The absence of viral RNA in FF of women only screened through a symptom questionnaire is reassuring concerning the safety of IVF during Covid pandemic.

Trial registration number

Not applicable

Arterial aging mediates the effect of TNF-α and ACE polymorphisms on mental health in elderly individuals: insights from IKARIA study

BACKGROUND

Aging is characterized by an insidious decline in cognitive function. Several genetic and lifestyle factors have been implicated in the increased risk or early onset of dementia.

AIM

We sought to assess the role of tumor necrosis factor (TNF) and angiotensin-converting enzyme (ACE) polymorphisms on the development of impaired mental health in respect to indices of arterial aging in nonagenarian individuals.

DESIGN

178 consecutive subjects above 75 years that permanently inhabit in the island of IKARIA, Greece were recruited.

METHODS

Aortic distensibility (AoD) was calculated and genetic evaluation was performed on the ACE Insertion/Deletion gene polymorphism (intron 16) and the G/A transition (position -308) of the TNF gene. Cognitive function was evaluated using the Mini-mental State Examination (MMSE).

RESULTS

The DD genotype for ACE was independently associated ( b  = -0.44, P = 0.007) with AD while AoD remained an independent determinant of mental status (OR = 1.82, P = 0.036). Interestingly though, when a combined genetic index (GI) was calculated for both genes (ACE and TNF), subjects being double homozygous (DD for ACE and GG for TNF) for these loci presented significantly decreased MMSE (adjusted OR = 0.259, P = 0.033). This GI independently associated with AD (beta coefficient = -0.785, P = 0.002). When AoD was included, GI lost its predictive role (OR = 0.784, P = 0.783) towards MMSE. AoD has marginal indirect mediating effect in the association of the GI with MMSE ( P = 0.07).

CONCLUSION

Vascular aging may modulates the genetic substrate of elderly subjects on the risk for developing dementia.

Similar in vitro maturation rates of oocytes retrieved during the follicular or luteal phase offer flexible options for urgent fertility preservation in breast cancer patients

STUDY QUESTION

Are in vitro maturation (IVM) rates of cumulus-oocyte complexes (COCs), retrieved from breast cancer patients seeking urgent fertility preservation (FP) before neoadjuvant chemotherapy, different between those recovered in the follicular or in the luteal phase of the cycle?

SUMMARY ANSWER

The present investigation reveals no major difference in the number of COCs recovered or their IVM rates whatever the phase of the cycle at which egg retrieval is performed, suggesting that IVM is a promising tool for breast cancer patients seeking urgent oocyte cryopreservation.

WHAT IS KNOWN ALREADY

FP now represents a standard of care for young cancer patients having to undergo gonadotoxic treatment. Mature oocyte cryopreservation after IVM of COCs has been proposed for urgent FP, especially in women, who have no time to undergo ovarian stimulation, or when it is contraindicated.

STUDY DESIGN, SIZE, DURATION

From January 2011 to December 2014, we prospectively studied 248 breast cancer patients awaiting neoadjuvant chemotherapy, aged 18-40 years, candidates for oocyte vitrification following IVM, either at the follicular or the luteal phase of the cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Serum anti-Müllerian hormone and progesterone levels and antral follicle count (AFC) were measured prior to oocyte retrieval. Patients were sorted into two groups according to the phase of the cycle during which eggs were harvested (Follicular phase group, n = 127 and Luteal phase group, n = 121). Number of COCs recovered, maturation rates after 48 h of culture and total number of oocytes cryopreserved were assessed. Moreover, the oocyte retrieval rate (ORR) was calculated by the number of COCs recovered ×100/AFC.

MAIN RESULTS AND THE ROLE OF CHANCE

In the Follicular and the Luteal phase groups, women were comparable in terms of age, BMI and markers of follicular ovarian status. There was no significant difference in the number of COCs recovered (mean ± SEM), 9.3 ± 0.7 versus 11.1 ± 0.8, and ORR (median (range)) 43.1 (1-100) versus 47.8 (7.7-100)%. Moreover, maturation rates after 48 h of culture (median (range)) were comparable in the follicular and luteal phase groups, 66.7 (20-100) versus 64.5 (0-100)%. Finally, the total number of oocytes cryopreserved (mean ± SEM) was similar in both groups (6.2 ± 0.4 versus 6.8 ± 0.5).

LIMITATIONS, REASONS FOR CAUTION

Despite the intact meiotic competence of immature oocytes recovered during the follicular or the luteal phase, there is a dramatic lack of data regarding the outcome of IVM oocytes cryopreserved in cancer patients.

WIDER IMPLICATIONS OF THE FINDINGS

IVM of oocytes may be an interesting method of FP in urgent situations. Improving the culture conditions will be needed to increase the maturation rates and the overall potential of in vitro matured oocytes.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

N/A.

Lifestyle and nutrition related to male longevity in Sardinia: an ecological study

BACKGROUND AND AIMS

A demographic analysis in the Mediterranean island of Sardinia revealed marked differences in extreme longevity across the 377 municipalities and particularly identified a mountain inner area where the proportion of oldest subjects among male population has one of the highest validated value worldwide. The cause(s) of this unequal distribution of male longevity may be attributed to a concurrence of environmental, lifestyle and genetic factors.

METHODS AND RESULTS

In this study we focussed on some lifestyle and nutrition variables recorded in the island's population in early decades of 20th century, when agricultural and pastoral economy was still prevalent, and try to verify through ecological spatial models if they may account for the variability in male longevity. By computing the Extreme Longevity Index (the proportion of newborns in a given municipality who reach age 100) the island's territory was divided in two areas with relatively higher and lower level of population longevity. Most nutritional variables do not show any significant difference between these two areas whereas a significant difference was found with respect to pastoralism (P = 0.0001), physical activity estimated by the average slope of the territory in each municipality (P = 0.0001), and average daily distance required by the active population to reach the usual workplace (P = 0.0001).

CONCLUSION

Overall, these findings suggest that factors affecting the average energy expenditure of male population such as occupational activity and geographic characteristics of the area where the population mainly resides, are important in explaining the spatial variation of Sardinian extreme longevity.

Metabolic and inflammatory profile in obese patients with chronic obstructive pulmonary disease

BACKGROUND

Overweight and obesity have been associated with better survival in patients with chronic obstructive pulmonary disease (COPD). On the other hand, excess body weight is associated with abnormal metabolic and inflammatory profiles that define the metabolic syndrome and predispose to cardiovascular diseases. This study was undertaken to evaluate the impact of overweight and obesity on the prevalence of the metabolic syndrome and on the metabolic and inflammatory profiles in patients with COPD.

METHODS

Twenty-eight male patients with COPD were divided into an overweight/obese group [ n = 16, body mass index (BMI) = 33.5 +/- 4.2 kg/m(2)] and normal weight group (n = 12, BMI = 21.1 +/- 2.6 kg/m(2)). Anthropometry, pulmonary function and body composition were assessed. The metabolic syndrome was diagnosed according to waist circumference, circulating levels of triglyceride and high-density lipoprotein cholesterol levels, fasting glycemia and blood pressure. C-reactive protein, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), leptin and adiponectin plasma levels were measured.

RESULTS

Airflow obstruction was less severe in overweight/obese compared with normal weight patients (forced expiratory volume(1): 51 +/- 19% versus 31 +/- 12% predicted, respectively, P < 0.01). The metabolic syndrome was diagnosed in 50% of overweight/obese patients and in none of the normal weight patients. TNF-alpha, IL-6 and leptin were significantly higher in overweight/obese patients whereas the adiponectin levels were reduced in the presence of excess weight.

CONCLUSIONS

The metabolic syndrome was frequent in overweight/obese patients with COPD. Obesity in COPD was associated with a spectrum of metabolic and inflammatory abnormalities.

[Incidence of individualized training on exercise-induced desaturation in COPD patients]

BACKGROUND

Exercise-induced desaturation is a well-described phenomenon in COPD patients during exercise assessments such as the six minute walk test (6MWT). Some of the pathophysiological mechanisms involved in this O2 desaturation could be modified by individualized exercise training as part of a pulmonary rehabilitation programme. The aim of this study was to determine the effect of pulmonary rehabilitation on O2 desaturation exhibited by COPD patients during a 6MWT.

METHODS

Twenty COPD patients (FEV1=61.1 +/- 3.2% predicted) who exhibited O2 desaturation before rehabilitation (mean 7.3 +/- 0.7% with a mean duration of 5.3 +/- 0.1 min) participated. They performed four weeks of RP including individualized whole-body exercise training achieving a mean 9.3 +/- 0.27 hours per week of exercise tailored to their ventilatory threshold.

RESULTS

Dyspnoea at the end of the test, ventilatory threshold and FEV1 were retained as correlates of desaturation before rehabilitation. After rehabilitation, 6MWT distance increased (p<0.01) with reduced dyspnoea (p<0.05). Two sub-groups were identified: persistent desaturaters (DS, n=13) and non-desaturaters group (NDS, n=7). There were no baseline differences between the two groups. After rehabilitation only the persistent desaturaters showed a significant increase in distance achieved during 6MWT associated with a reduced dyspnea (p<0.05). This group showed a mean O2 desaturation equal to 8.1 +/- 0.9% which persisted to 5 +/- 0.3 min. A tendency to a lower dyspnoea at the end of 6MWT performed before rehabilitation was observed in NDS compared with DS (p<0.058).

CONCLUSION

It seems that responses to a pulmonary rehabilitation programme including individualized exercise training could act on O2 desaturation. Indeed 7 of 20 (35%) COPD patients exhibiting O2 desaturation during a 6MWT showed no O2 desaturation after rehabilitation programme while 13 on 20 (65%) do it.

Sexuality and Chronic Respiratory Disease

Background: At the admission in rehabilitation program, some patients with chronic respiratory disease were asked by a health professional to to answer a questionnaire about their sexuality. The objectives of the study were 1) to determine if sexual problems occurred in patients with respiratory chronic disease ; 2) to assess if these survey problems were linked to respiratory disease; 3) to explore the motivation to speak about sexuality during rehabilitation program. Methods: 52 consecutive respiratory disease subjects (58.3 ± 9 yr; FEV1 = 65.5 ± 21 % predicted, mean ± SD) answered a sexuality questionnaire survey with rehabilitation team (psychologists, nurses, physiotherapists). This group comprised 26 men and 26 women. Results: 70% of patients estimated that respiratory disease had an impact on their sexuality. A visual analog scale showed that 62% of patients were not satisfied. The severity of obstruction (FEV1) was not correlated to satisfaction (r=.017, P=0.90), or frequency (r=.08, P=0.55). Breathlessness was the most important factor of discomfort in sexual activity (61.5%). Tiredness and cough came second (32% and 21% respectively). 63% of respiratory patients never spoke about their sexuality with a health professional. 60% would like the health professional to begin to talk about their sexuality. 36% of patients spoke about it with a professional. In this group, 94% of patients told the professional about their sexual activity on their own initiative. Conclusion: More than one of two chronic respiratory disease patients (77%) participating in a rehabilitation program want sexuality to be taken into consideration during their program.

Effect of weight reduction on quality of life and eating behaviors in obese women

OBJECTIVE

To examine the impact of a 3-week weight-reducing program on body composition, physical condition, health-related quality of life, and eating behaviors of sedentary, obese (body mass index, 29-35 kg/m) women, according to menopausal status and menopause duration (<5, >or=5, and >or=10 y).

DESIGN

Thirteen premenopausal and 27 postmenopausal women received a dietary plan of 1,400 +/- 200 kcal/day and completed 110-minute endurance exercise 6 days per week. Body mass index, fat mass, lean mass, distance walked in the Six-Minute Walk Test, health-related quality of life estimated by the 36-item Short Form Health Survey (SF-36), and eating behaviors (restriction, disinhibition, and susceptibility to hunger) assessed by the Three-Factor Eating Questionnaire were determined before and after weight reduction.

RESULTS

Body mass index and fat mass decreased (P < 0.0001), whereas distance walked increased in both groups after weight reduction (P < 0.001). Although the SF-36 mental component score increased after weight loss in both groups (P < 0.0001), the SF-36 physical component score increased in postmenopausal women only (P < 0.001). Restriction increased (P < 0.0001), whereas disinhibition and susceptibility to hunger decreased after weight reduction (P < 0.001 and P < 0.01, respectively) in both groups. Distance walked and SF-36 physical component score after weight loss were higher in women whose menopause ranged between 5 and 9 years and exceeded 10 years, respectively (P < 0.01).

CONCLUSIONS

Our study shows that a short-term weight-reducing program combining caloric restriction and physical activity has a favorable impact on women's body composition, physical condition, health-related quality of life, and eating behaviors irrespective of their menopausal status.

The effect of obesity on chronic respiratory diseases: pathophysiology and therapeutic strategies

Sedentary lifestyles and increased pollution brought about by industrialization pose major challenges to the prevention of both obesity and chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, obstructive sleep apnea and obesity hypoventilation syndrome. Obesity has emerged as an important risk factor for these respiratory diseases, and in many instances weight loss is associated with important symptomatic improvement. Moreover, obesity may influence the development and presentation of these diseases. In this article, we review the current understanding of the influence of obesity on chronic respiratory diseases and the clinical management of obesity concurrent with asthma, COPD, obstructive sleep apnea or obesity hypoventilation syndrome.

Gender difference in coping strategies among patients enrolled in an inpatient rehabilitation program

BACKGROUND

Previous research has not addressed gender differences in coping strategies among patients with mild to moderate chronic obstructive pulmonary disease (COPD) who are enrolled in inpatient and multidisciplinary rehabilitation programs.

METHODS

The coping strategies of 182 consecutive patients (61 women aged 61.1 years; 121 men aged 62.7 years) with mild to moderate COPD were assessed on admission and then at discharge after 29 days of pulmonary rehabilitation, using the Coping Inventory for Stressful Situations. A one-way analysis of variance for repeated measures was used to test the differences in coping scores.

RESULTS

During the rehabilitation program, problem-focused strategies increased (+2.54 [95% confidence interval: 1.41-3.67] with F=23.77, P<.0001), emotion-focused strategies decreased (-2.75 [95% confidence interval: -4.06, -1.45], F=15.37, P<.001), and avoidance strategies were differently (t=2.97, P<.05) influenced in women (+2.43 [95% confidence interval: .66-4.19]) compared with men (-1.30 [95% confidence interval: -2.82-.22]). The prevalence of COPD in women is increasing, and rehabilitation professionals need a greater awareness of how women cope differently than men with this disease.

Undiagnosed exercise-induced bronchoconstriction in ski-mountaineers

Because the practise conditions put the ski-mountaineering athletes potentially at risk for exercise-induced bronchoconstriction (EIB), this study was conducted to estimate the prevalence of EIB in this population. Thirty-one highly-trained ski-mountaineers with racing experience participating in the race were evaluated. EIB was determined after a European race at high altitude and frigid conditions. Pre-race investigations included pulmonary function measurements and a questionnaire enquiring about i) training habits, ii) respiratory history during training and/or competition. Pulmonary function was also tested after the race. None of the athletes reported a basal airway obstruction. Two groups were determined after post-race airway response: i) EIB (+) group exhibiting a fall in FEV (1) > or = 10 % (n = 15) and ii) EIB (-) without fall in FEV (1) or fall < 10 % (n = 16). Neither training habits nor baseline lung function were associated with the post-race airway response. Six of the 31 ski-mountaineers had a previous physician-made diagnosis of asthma and/or EIB, nevertheless 23 of our athletes complained about at least one characteristic symptom of asthma during practise. Four of our 15 EIB (+) had a previous physician-made diagnosis of asthma/EIB indicating that 73 % of EIB (+) athletes were undiagnosed for EIB. The proportion of allergic athletes was not significantly different between EIB (+) and EIB (-). This study showed that approximatively half of highly-trained ski-mountaineers with racing experience can develop EIB after a race and that 73 % of them are unaware of the problem.

Effect of acute hyperoxia during exercise on quadriceps electrical activity in active COPD patients

AIMS

This study investigated whether acute hyperoxia improves electrical muscle activity in active chronic obstructive pulmonary disease (COPD) patients with mild hypoxemia (rest PaO(2) = 9.1 +/- 0.4 kPa).

METHODS

Two identical incremental exercise tests were performed by nine patients while breathing either air or 30% oxygen. Pulmonary gas exchanges, venous concentrations of lactate and pyruvate, and the electromyographic signal of the quadriceps muscle (vastus lateralis and vastus medialis) were sampled each minute.

RESULTS

Peak working capacity increased significantly in hyperoxia (94.4 +/- 5.2W) compared with normoxia (85.4 +/- 5.8W, P < 0.01). During hyperoxic exercise and for a given work load, oxygen uptake was increased (P < 0.001) and ventilation decreased (P < 0.05). Lactate concentration was significantly decreased (P < 0.01) at isowork level and during recovery (respectively - 26% and at least - 15%). In the quadriceps muscle, M-wave amplitude (P < 0.05), root mean square (P < 0.01) and root mean square/oxygen uptake ratio (P < 0.001) were significantly increased during hyperoxic exercise compared with room air. Although median frequency values did not differ between conditions, the median frequency was significantly decreased for higher exercise intensity in hyperoxic condition. These modifications reflected better aerobic metabolism, later emergence of muscle fatigue, and greater muscle excitability and activation for the same level of exercise under hyperoxic condition.

CONCLUSION

These data suggest that the acute addition of oxygen in active COPD patients improves their muscle electrical activity during dynamic exercise. Hypoxemia-induced skeletal muscle dysfunction most probably acts through mechanisms based on oxygen availability.

Endurance training improves skeletal muscle electrical activity in active COPD patients

The effect of endurance training on muscle electrical activity during general exercise testing was investigated in physically active patients with chronic obstructive pulmonary disease (COPD). Before and after rehabilitation, patients performed identical incremental exercise tests. Pulmonary gas exchange, venous lactate and pyruvate concentrations, and the quadriceps electromyographic signal were sampled every minute throughout exercise testing. Three weeks of rehabilitation increased exercise capacity without modifying pulmonary function. M-wave amplitude, root mean square (RMS) of electromyographic activity, and RMS/oxygen uptake were increased significantly during post-rehabilitation testing at the same exercise intensity compared to pre-rehabilitation. Median frequency was significantly lower after training. These modifications reflect greater muscle excitability, greater muscle activation for the same level of exercise, and higher recruitment of slow-twitch fibers. Pulmonary rehabilitation in active COPD patients may normalize the electrical activity of skeletal muscles during incremental dynamic exercise. The electromyographic signal confirms neuromuscular changes after endurance training.

6-minute walk testing is more sensitive than maximal incremental cycle testing for detecting oxygen desaturation in patients with COPD

STUDY OBJECTIVES

Some respiratory patients exhibit oxygen desaturation during rehabilitative walking but not during maximal cardiopulmonary exercise testing (CPET). We evaluated exercise-induced desaturation during 6-min walk testing (6MWT) in comparison with CPET in patients with COPD and determined the reproducibility of the phenomenon.

PATIENTS

We tested 80 consecutive patients with COPD (FEV(1), 62.4 +/- 2% predicted) and 10 patients with supplementary COPD (FEV(1), 59.1 +/- 5% predicted) [mean +/- SEM] to determine the reproducibility.

MEASUREMENTS AND RESULTS

First, patients with COPD performed cycle CPET (first CPET [CPET-1]). Three days later, they performed two 6MWTs (first 6MWT [6MWT-1] and second 6MWT [6MWT-2]). Pulse oximetric saturation (SpO(2)) was recorded every minute in both tests. Three groups emerged: desaturation at 6MWT not observed at CPET (DND) [n = 23], desaturation in both tests (n = 16), and no desaturation in either test (n = 41). Second, to evaluate reproducibility, 10 additional subjects with COPD who exhibited desaturation during two successive 6MWTs but not in CPET performed a second CPET (CPET-2) and a single-bout 6MWT (6MWT-3) in a supplementary trial. When two CPETs were performed, lack of O(2) desaturation was noted in both. O(2) desaturation was confirmed in 6MWT-2 and 6MWT-3 (7.4 +/- 1% and 7.4 +/- 1.5%, respectively).

CONCLUSION

Twenty-eight percent of patients with COPD presented DND. The phenomenon was reproducible and not protocol dependent, emphasizing the clinical interest of the 6MWT.

Electrophysiologic changes during exercise testing in patients with chronic obstructive pulmonary disease

To determine whether skeletal muscle is involved in the exercise limitation of chronic obstructive pulmonary disease (COPD), we investigated electrical adaptations in muscle during incremental cycling exercise testing. Changes in quadriceps activity were compared using surface electromyography (SEMG) and motor point stimulation in ten COPD patients and ten healthy subjects. Patients showed significantly lower exercise capacity, and M-wave duration was increased from exercise onset (P < 0.05) with a parallel decrease in amplitude (P < 0.05). The SEMG power spectrum median frequency was always higher (P < 0.04) in patients and its decline was earlier (P < 0.01). The ratio of the root mean square of the SEMG to oxygen uptake was decreased (P < 0.001) during exercise in patients, although it remained constant in controls. Electromyographic parameters were significantly more involved in the exercise limitation than ventilatory factors. Thus, modified electrical activity in muscle appeared in COPD patients from exercise onset, indicating that skeletal muscle function is clearly implicated in the exercise intolerance of these patients.

[Confronting the statistics on intra-European migration: toward greater harmonization?]

"Each international migration stream can be enumerated twice: at the time of departure from the country of emigration and at the time of arrival in the country of immigration. In practice, errors in international migration statistics are a major obstacle to the accurate analysis of migration flows. In connection with the process of harmonization set in train by Eurostat several years ago, a method of correcting defective migration data is proposed here, which makes use of this double enumeration. The method is applied to available data in a preliminary analysis. The correction factors presented here through this mathematical approach should turn out to be useful in more than one respect: to illuminate substantial problems of incompatibility of migration data and to follow the progress of the harmonization of those data." (SUMMARY IN ENG)

[Migratory flows in the Mediterranean Basin]

Recent trends in international migration in the Mediterranean region are analyzed, with the focus on South-North migration to Europe. "This migration towards Western Europe has taken various forms, from labour force migration, in a first phase, to family reunification, and more recently, asylum requests and irregular immigration. These migratory flows must be understood within the context of a severe imbalance--demographic and economic--between the Southern and Northern banks of the Mediterranean. Europe and especially the European Union is directly confronted by this persistent migratory pressure coming from the other Mediterranean countries. Its future can only be conceived of through new and innovative forms of cooperation with its Mediterranean partners." (SUMMARY IN ENG)

Prediction of VO(2peak) in wheelchair-dependent athletes from the adapted Léger and Boucher test

PURPOSE

:The purpose of this study was to provide a predictive peak oxygen uptake ([V]O(2) peak) equation in wheelchair-dependent athletes using the Adapted Léger and Boucher test. SUBJECTS AND PROTOCOL: :Fifty-six wheelchair-dependent athletes, 47 males and nine females (30.3+/-4 years), underwent a clinical examination to assess their anthropometric characteristics: height, mass, body mass index (BMI), lean body mass, arm length, and muscular arm volume. They performed a deceleration field test to assess the subject-wheelchair resistance defined as a mechanical variable, and they then performed the Adapted Léger and Boucher test to assess physiological data at maximal exercise ([V]O(2) peak, heart rate max) concomitantly with biomechanical (number of pushes) and performance variables (maximal aerobic velocity Va(max) and maximal distance). The [V]O(2) peak was measured directly using a portable telemetric oxygen analyzer. Subjects were then randomly assigned to an experimental group (n=49) to determine the predictive equation, and a validation group (n=7) to check the external validity of the equation.

RESULTS

A stepwise multiple regression with [V]O(2) peak (l min(-1)) as the dependent variable led to the following equation: [V]O(2) peak=0.22 Va(max) - 0.63 log(age)+0.05 BMI 0.25 level+0.52, with r(2)=0.81 and SEE=0.01. Paraplegic subjects with high and low lesion level spinal injuries were attributed the coefficient of 1 and 0, respectively. The external validity of the equation was positive since the predicted [V]O(2) peak values did not significantly differ from directly measured [V]O(2) peak (P>0.05).

CONCLUSION

We concluded that [V]O(2) peak in wheelchair-dependent athletes was predictable using the equation of the present study and the described incremental test.

[Daltonism and the genetics of aging]

In order to test whether mutations giving rise to color vision deficiencies are more frequently inherited from older fathers, an exhaustive screening of births in the Namur region has allowed to isolate a sample of 225 descending sons of maternal grandfathers who were older than 45 years at their daughter's birth. The incidence of color vision defects was compared between this set of cases and three control groups totalling 959 boys from independent families. While these comparisons were not conclusive, we propose new hypotheses concerning the population dynamics of color vision deficiencies. Neomutations in X-linked pigment genes may be a marker of the overall genetic load borne by the X chromosome. Selection against such loaded X chromosomes may occur in the second generation, either in the course of embryogenesis, or during female gametogenesis. The future assessment of these novel hypotheses relies on the arbitration of molecular genetics.

Reproducibility of the Adapted Leger and Boucher Test for wheelchair-dependent athletes

STUDY DESIGN

This study analyzed the reproducibility of a field test. In a previous study, we showed that this test, the Adapted Leger and Boucher Test (ALBT), was progressive and maximal. The Leger and Boucher predictive equation for able-bodied subjects was not accurate for WD athletes, however, and a new predictive equation is needed.

OBJECTIVES

To determine the reproducibility of an adapted incremental field test for wheelchair-dependent (WD) athletes.

SETTING

France at Montpellier.

METHODS

The proposed protocol was conducted on a 400 m track. Eight male paraplegics (mean age: 30.8+/-5.1 years) performed the test three times in the same conditions, ie same time of day, same wheelchair, same material. Maximal heart rate (HRmax) and maximal speed (Smax) were measured.

RESULTS

We found no significant differences (P>0.05) between tests for either variable. The Bland and Altman graphic analyses showed a good reproducibility for both variables. Lastly, the reproducibility coefficients of HRmax and Smax were very low (2% and 1%, respectively).

CONCLUSION

The ALBT is reproducible concerning measurements of HRmax and Smax. A valid predictive equation of maximal oxygen uptake from the Smax is now needed for WD athletes during this field test.